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   Science & Technology Review
2016, Vol.34, No. 2
28 January 2016

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Science & Technology Review. 2016, 34 (2): 3-3.
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Abstract ( 475 )

Science & Technology Review. 2016, 34 (2): 9-10.
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Science & Technology Review. 2016, 34 (2): 12-12.
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Science & Technology Review. 2016, 34 (2): 14-15.
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Abstract ( 569 )

Science & Technology Review. 2016, 34 (2): 323-323.
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Abstract ( 665 )

Science & Technology Review. 2016, 34 (2): 324-324.
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Abstract ( 694 )

Science & Technology Review. 2016, 34 (2): 332-332.
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Abstract ( 652 )
Foreword

Science & Technology Review. 2016, 34 (2): 1-1.
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Abstract ( 684 )
News Around

Science & Technology Review. 2016, 34 (2): 11-11.
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Abstract ( 626 )
News Focus

Science & Technology Review. 2016, 34 (2): 13-13.
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Abstract ( 643 )
Suggestion

Science & Technology Review. 2016, 34 (2): 16-16.
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Abstract ( 550 )

Science & Technology Review. 2016, 34 (2): 17-17.
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Abstract ( 636 )
Exclusive

Progress of applications of the Prussian blue in cancer diagnosis and therapy

CAI Xiaojun, MA Ming, CHEN Hangrong, SHI Jianlin
Science & Technology Review. 2016, 34 (2): 18-26. ;  doi: 10.3981/j.issn.1000-7857.2016.2.001
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Abstract ( 1244 )
With good biocompatibility and biological safety, the Prussian blue (PB) is used as a clinical medicine for the treatment of radioactive exposure, which is approved by the USA Food and Drug Administration. Owing to the easiness of the control of size, structure, surface modification and its other good performances, the PB nanoparticles (PB NPs) play an important role in the biomedical field including the drug delivery system (DDS), the molecular imaging, the gene therapy, and the photothermal therapy. This paper reviews the most recent research advances and discusses the future development trends of the applications of the PB-based nanotheranostics in the diagnosis including the photoacoustic imaging (PA), the magnetic resonance imaging (MRI), the ultrasonic imaging (US) and the multimodal imaging, as well as in the therapy including the photothermal therapy, the gene therapy and the chemotherapy.

Progress in preparation of Janus nanoparticles by self-assembly of block copolymers

LIU Shanqin, ZHANG Yijun, DENG Renhua, MEI Luping
Science & Technology Review. 2016, 34 (2): 27-32. ;  doi: 10.3981/j.issn.1000-7857.2016.2.002
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Abstract ( 815 )
The Janus particles of two compositions or properties distinctly compartmentalized have important applications in stabilizing emulsion, drug carriers, interfacial catalysis, and building superstructures. Especially, the Janus nanoparticles of block copolymers with covalently linked compartments are strong in structure, and have attracted growing interests due to their nano-size, the flexible structures, and the response to solvent, pH value, temperature or other stimuli. It is important to develop new methods for a large-scale synthesis of Janus nanoparticles with tunable morphology, structure and chemical composition. This review summarizes the recent progress in the preparation of block copolymer Janus nanoparticles. Some important methods are discussed and compared in detail, which is conducive to the design and the preparation of the Janus nanoparticles for potential applications.

Design of dispatching rules in dynamic job shop scheduling problem

FAN Huali, XIONG Hegen, JIANG Guozhang, LI Gongfa
Science & Technology Review. 2016, 34 (2): 33-38. ;  doi: 10.3981/j.issn.1000-7857.2016.2.003
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Abstract ( 811 )
The dispatching rule is an effective tool for solving the dynamic job shop scheduling problem in practical productions. However, no single rule can outperform others under various scheduling circumstances, as the effectiveness of the dispatching rule depends on the shop configurations, the operating conditions and the performance measures. To study the dynamic job shop scheduling problem in practical productions, the methods for the development and the design of dispatching rules are reviewed in this paper. The development, the classification and the characteristics of dispatching rules are discussed, and the research hotspots of dispatching rules and the design methods are summarized. The design methods of dispatching rules include the popular manually performed method and the effective artificial intelligence method. In addition, the research results and the conclusions of the evolutionary algorithm, the genetic programming and the data mining methods for the design of dispatching rules are presented. The advantages and disadvantages of these methods are analyzed and compared. Finally the direction of future researches is pointed out.

In-situ fabrication and device simulation of molybdenum disulfidesilicon heterojunction solar cell

LI Shenghao, DAN Yi, SHEN Hui
Science & Technology Review. 2016, 34 (2): 39-42. ;  doi: 10.3981/j.issn.1000-7857.2016.2.004
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Abstract ( 736 )
Heterojunction solar cells formed by two-dimensional materials and crystalline silicon are one of the research highlights in the field of solar cells. Most researches focus on the graphene-silicon Schottky junction solar cells. To refine the band-gap structure of these devices, we have fabricated the two-dimensional semiconductor material of n-MoS2, which has a band-gap, on the surface of p-Si to form heterojunction solar cells. Our experiment has revealed the effect of annealing time on the synthesis of MoS2. Dark and light current-voltage curves of MoS2-Si heterojunction are measured and discussed. The heterostructure simulation software wx-AMPS is applied for the efficiency calculation and the energy band analysis. The effects of MoS2 thin film thickness and carrier concentration on the open-circuit voltage are studied.

Fabrication of CIS thin film by sputtering one ternary target

WU Zhao, HONG Ruijiang
Science & Technology Review. 2016, 34 (2): 43-45. ;  doi: 10.3981/j.issn.1000-7857.2016.2.005
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Abstract ( 1070 )
The CIGS solar cells have drew much attention recently because of its specific advantages such as high efficiency, good performance under low illumination, resistance to radiation and flexible bandgap. The CIGS absorber layer can be fabricated by coevaporation, sputtering, electrical deposition and many other methods and sputtering is considered to be the most suitable way for large scale fabrication. In this paper CIS thin films were deposited on both SLG and Mo coated SLG substrates by sputtering one ternary target followed by post annealing. CIS thin film with good crystallinity under optimal process parameters was obtained. The effects of different substrate temperatures in deposition process and annealing temperature on the crystallization of the thin films were investigated. We found that the crystallinity of the CIS thin film deposited at 150℃ was improved after post annealing while the annealing temperature had slight effect on the crystallization of CIS thin film on Mo coated SLG substrate. The result also shows that density of the target has significant influence while sputtering ternary target.

Optimization of the extraction conditions of Elaeagnus mollis kernel oil by response surface methodology

ZHU Yahong, WANG Junqi, SU Yinquan, HUANG Xiaohua, ZHU Mingqiang
Science & Technology Review. 2016, 34 (2): 46-52. ;  doi: 10.3981/j.issn.1000-7857.2016.2.006
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Abstract ( 658 )
In this paper, an experimental method of the central composite design is used to determine the kernel oil content in the Elaeagnus mollis preparation. Based on the Design Expert software, a quadratic model is established with independent variables of the kernel oil content, such as the extraction time, the extraction temperature and the material-liquid ratio. The response values satisfying all expectations are optimized, and the most excellent extraction conditions of the Elaeagnus mollis kernel oil are 45 min for the extraction time, 88℃, for the extraction temperature and 1:5 for the material-liquid ratio. Under these conditions, the actual extraction rate of the kernel oil is 92.44%. The result of the verification experiment for the formulation is consistent with the prediction. The fatty acids in the Elaeagnus mollis kernel oil are analyzed by GC-MS. The results show that 28 kinds of fatty acids and 9 kinds of unsaturated fatty acids are identified. They are mainly composed of 12.86% methyl oleic, 10% methyl palmitate, pentadecanoic, 9.78% acid methyl ester, and 16.57% linoleic acid methyl. This extraction method is an environmentally benign and advantageous scheme for the production of kernel oil from Elaeagnus mollis, which will be further transformed into the value-added biomaterials and bioethanol.

Impacts of renewable energy generations on the safety of the distribution system

LI Rui, WANG Wei, WU Xuezhi, HE Yongjing
Science & Technology Review. 2016, 34 (2): 53-58. ;  doi: 10.3981/j.issn.1000-7857.2016.2.007
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Abstract ( 1091 )
The fluctuation and the randomness of REG's output have severe impacts on the safety and stability of the operation. To guarantee a stable operation of the distribution system, the important impacts of the REGs on the safety operation of the distribution system are analyzed in six aspects, including the power transmission, the power quality, the frequency stability, the islanding effects, the protection, and the planning. To cope with these impacts, the corresponding suggestions, such as the formulation of a comprehensive safety and stabilization guide, the optimization of the network structure, and the improvement of the REGs' stability and controllability, are proposed. Particularly, the coordinated planning method for the distribution network is discussed in detail. The in-depth analysis of the planning model is presented.

Method for wind turbine blade FSI numerical simulation

WANG Weilong, TIAN De, DENG Ying, LIN Junjie
Science & Technology Review. 2016, 34 (2): 59-64. ;  doi: 10.3981/j.issn.1000-7857.2016.2.008
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Abstract ( 962 )
Taking a 5 MW wind turbine blade as an example in our research, a rotor rotation simulation for the fluid-structure interaction is made. The combination of the wind rotation speed and the inflow velocity is simulated by considering the wind shear effect, and the torsion angles of the blade airfoil at different cross sections are modified, to establish the rotation simulation model of a wind turbine blade. The wind tunnel test of the wind turbine blade is simulated through a finite element software. The air pressure and the flow speed under the rotation effect around the blade together with the blade surface pressure are simulated. Using a data exchange platform to exchange the blade structure displacement and the surface pressure data, obtained through structure and fluid calculations, respectively, the fluidstructure interaction results are obtained. The results are compared with those at the rated wind speed and the reference experiment, and the rotation simulation method is verified.

A comprehensive error modeling method for numerical control machine tools based on time-varying characteristics

LI Jie, LIU Xinjun, XIE Fugui, LI Weidong, ZHU Shaowei
Science & Technology Review. 2016, 34 (2): 65-70. ;  doi: 10.3981/j.issn.1000-7857.2016.2.009
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Abstract ( 967 )
Based on the time-varying characteristics of the error components, a comprehensive error modeling method for a B-A swiveling head 5-axis machine tool is proposed. First, the dynamic error components are expressed as the Fourier series that are associated with the speed and the acceleration of the moving platform. Then, joint error transformation matrixes are modeled as the synthesis of the static and dynamic error transformation matrixes. Subsequently, the error mapping between the trajectory errors of the cutting tool and the joint error sources are constructed based on the MBS method. Finally, a theoretical analysis is made and the results show that both the kinematic and dynamic accuracy impacting factors are considered in this method, which can reflect the machining errors of the machine tools more accurately and also provide a solid foundation for the error compensation and the control parameter modulation.

Analysis of contributing factors on heavy-duty truck accidents in long downgrade road sections

LI Haoran, PENG Liqun, WU Chaozhong, CHU Duanfeng
Science & Technology Review. 2016, 34 (2): 71-75. ;  doi: 10.3981/j.issn.1000-7857.2016.2.010
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Abstract ( 716 )
Long downgrade road sections are dangerous parts for heavy-duty truck accidents. Most of current researches on heavy-duty truck accidents are focused on the speeding of truck, which ignore other factors (weather, vehicle types, driver attribute, etc.). Through analysis of accident data in long downgrade sections of Luofu Freeway in Yunnan Province, the effects of weather, vehicle types, driver attribute, etc. on heavy-duty truck accidents are studied in this paper. First, descriptive statistical analysis method is used to study the accident distribution of different factors. Then using K-mean clustering method, the factors are divided into three clusters based on their effects on accident severity (accident number, occupant injuries, and deaths). The study results show that non-local trucks, 6-axle trucks and 00:00-07:59 are the most important factors on accident severity in long downgrade road sections; fog, rain and low temperature have little effects on accidents in long downgrade road sections. The study results may be used as a reference basis to improve heavy-duty truck transportation safety in long downgrade road sections.
Reviews

Research progress of left ventricular function in metabolic syndrome

ZHOU Qinghua
Science & Technology Review. 2016, 34 (2): 76-80. ;  doi: 10.3981/j.issn.1000-7857.2016.2.011
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Abstract ( 1355 )
The definition and clinical diagnostic criteria of metabolic syndrome (MS) are elaborated in this paper. The feature of left ventricular cardiac function changes of MS is identified through understanding of the relationships between hypertension, dyslipidemia, obesity, blood glucose abnormalities and left ventricular cardiac function. Decreased left ventricular function in patients with MS is caused by a number of cardiovascular risk factors, which lead to a number of complex metabolic reactions, affect the structure and metabolism of the myocardial environment and change the cardiac function and myocardial energy. Therefore, prior to development of symptomatic heart failure, MS patients may experience a period of subclinical left ventricular dysfunction.

Recent progress of biological imaging based on noble nanomaterials

DONG Xiawei, WANG Xuemei
Science & Technology Review. 2016, 34 (2): 81-85. ;  doi: 10.3981/j.issn.1000-7857.2016.2.012
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Abstract ( 1374 )
Noble metal nanomaterials, with the unique characteristics including light stability, strong optical signal, good bio-compatibility and so on, have incomparable advantages over other materials. They have been successfully utilized in various scientific and living areas, with broad application prospects in the area of life science and biological medicine, attracting more and more attention all over the world. This article simply summarizes the advantages and disadvantages of fluorescence imaging, Raman imaging, and the imaging principle of dark field imaging. The dark field imaging detecting scattered light of nanomaterials can eliminate effectively the background interference of sample, which has a lot of incomparable advantages. We review the latest research progress and prospect in biological imaging of noble metal nanomaterials. With the rapid development of nanometer composite technology and the improvement of detection means, noble metal nanomaterials will be brought from fundamental scientific research into practical application. And single molecular spectroscopy and optical microscopic imaging technology has made great progress, which is likely to bring new revolution in biological imaging characterization.

Copper corrosion behavior in the disposal of highly radioactive nuclear waste

KONG Decheng, MAO Feixiong, DONG Chaofang, XIAO Kui, LI Xiaogang
Science & Technology Review. 2016, 34 (2): 86-93. ;  doi: 10.3981/j.issn.1000-7857.2016.2.013
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Abstract ( 1473 )
With the rapid development of nuclear industry, the disposal of highly radioactive waste becomes a major safety and environmental issue, and the deep geological disposal is a generally accepted solution. For the reduction and the anaerobic disposal repository of granite, the suitable canister material is the high-purity copper. This paper reviews the domestic and foreign researches of the electrochemical behavior of the copper corrosion in the high-level waste environment, including the geological environment of the repository, the mechanism and the process of the copper corrosion and the life prediction of the copper canister. This paper provides a theoretical basis for better assessment of the corrosion resistance of the copper and precise prediction of the disposal canister life in the repository environment.

Review of experimental researches on concrete beams shear-strengthened with fiber reinforced polymer

LIU Huaxin, LIU Genjin, KONG Xiangqing, WANG Xuezhi
Science & Technology Review. 2016, 34 (2): 94-98. ;  doi: 10.3981/j.issn.1000-7857.2016.2.014
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Abstract ( 1341 )
This paper summarizes three different FRP shear reinforcement methods based on the available research results of FRP shear reinforcement beams. The experimental investigation history of externally bonded method and near surface mounted method is introduced and the advantages and disadvantages of each method are discussed. The article also points out that the ETS technique is a blank in domestic research and application. The experimental study history and status of the embedded through-section method are summarized and expounded according to the existing foreign literature in this field, in order to provide a reference for relevant domestic research and application. Finally, some suggestions of experimental study on FRP shear-strengthened are presented, and the research direction is also prospected.

Research progress of blast-resistant performance of reinforced concrete beams under blast loads and reinforcement technology

QU Yandong, LI Xin, KONG Xiangqing, SUN Conghuang
Science & Technology Review. 2016, 34 (2): 99-103. ;  doi: 10.3981/j.issn.1000-7857.2016.2.015
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Abstract ( 1419 )
Explosion may lead to severe damage to buildings, even catastrophic collapse, consequently, loss of lives and property. Dynamic response and strengthening techniques of reinforce concrete structure under blast loads are one of the hot topics in structure safety. As one of the main bearing components of building structure, the damage of reinforced concrete beams may cause the collapse of the whole structure under blast loads. A comprehensive overview of research progress of dynamic response, failure modes and strengthening technology of reinforced concrete beams is presented, meanwhile, the research emphasis and main development trend are put forward.

LA-ICP-MS zircon U-Pb dating of the rhyolite from the Zhonglü Group, northwestern Zhejiang Province, and its chronostratigraphic significance

HAN Yao, ZHANG Chuanheng, JIANG Xianqiang, YOU Guoqing, LIU Zihui
Science & Technology Review. 2016, 34 (2): 104-109. ;  doi: 10.3981/j.issn.1000-7857.2016.2.016
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Abstract ( 1394 )
The Zhonglü Group, outcropped in the northwestern part of Zhejiang Province, is a sequence of strongly-deformed, low-grade metamorphic clastic and volcanic rocks. It is overlaid unconformably by the Xiuning Formation, Nanhua period. Traditionally it is compared to the Shuangqiaoshan Group in the northeastern part of Jiangxi Province. This paper reports the LA-ICP-MS zircon U-Pb age of the rhyolite from the Zhonglü Group. The age of the Zhonglü Group is important to remodeling stratigraphic classification and correlation of Precambrian, and the mineralization geological background and conditions in the east part of South China are important as well. Sample A120408-4, collected from the north of Suzhuang fault, the middle-upper part of the Zhonglü Group, is massive rhyolite, which had been heavily foliated. Thirty-eight of the zircons were analyzed with LA-ICP-MS, and a weighed-mean U-Pb age of (777.1±3.6) Ma was obtained. Considering the stratum and metamorphic deformation characteristics, we draw the following conclusion: The main part of the Zhonglü Group is equivalent to the Shangshu Formation, Heshangzhen Group. Both of them belong to different facies of the same period, and they developed under the global tectonic background of Rodinia supercontinent cracking. The Zhonglü Group represents the cracking of the Yangtze ancient continent in the late neoproterozoic.

Sedimentary environments and sandbody distribution in member 2 of Permian Shanxi formation in mid-eastern Ordos Basin

YANG Wei, WANG Feng
Science & Technology Review. 2016, 34 (2): 110-115. ;  doi: 10.3981/j.issn.1000-7857.2016.2.017
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Abstract ( 1280 )
The member 2 of Lower Permian Shanxi formation is a main gas-producing reservoir and an important layer for exploration in the mid-eastern Ordos Basin. Outcrop analysis, core observation, comprehensive logging data interpretation and geochemical analysis suggest that the study area was affected by Marine facies at the early-middle stage of member 2 of Shanxi formation. It developed a rivertide controlled delta at the 2 and 3 sub-member of member 2 of Shanxi formation. The delta plain included distributary channel, abandoned channel, peat swamps and interdistributary depression. The delta front included sedimentary micro-facies, such as underwater distributary channel, mouth bar, distal bar, tide sand dam, and interdistributary bay. Seawater pushed out along the southeast Ordos Basin in the age of the 1 sub-member of member 2 of Shanxi formation. The study area developed a river controlled-lake delta on the background of terrestrial lakes. The differences of ancient geographical conditions lead to the different types of sand and reservoir properties. The reservoir sand in the 3 sub-member of member 2 of Shanxi formation was changed by the marine facies completely in the Mizhi-Zizhou and Tawan-Gaoqiao area. It has more advantages in lithologic characteristics, sand thickness and reservoir performance, which are favorable for gas exploration.

Reservoir control of contemporaneous faults in Qihuan Area of Western Slope in the western depression of Liaohe River Rifted Basin

CAO Tong, WANG Yanbin
Science & Technology Review. 2016, 34 (2): 116-120. ;  doi: 10.3981/j.issn.1000-7857.2016.2.018
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Abstract ( 1210 )
The contemporaneous faults are well-developed in the Qihuan Area of the Western Slope in the western depression of the Liaohe River Rifted Basin. Therefore, one should study the development characteristics and the control of these faults in order to make clear how these faults can influence the structures and reservoirs. These contemporaneous normal faults, characterized by the north-east strike listric faults tilting and sliding in the direction of sag, control the regional structure patterns. Furthermore, from the 3D seismic data, the contemporaneous fault growth index is computed. The relations between the fault growth index and the trap types are analyzed. Finally the general conclusion for this area is that the more intense the fault tectonic activity is, the more advantageous for the formation of local structures. The rollover anticline and the fault nose always develop in a down-dropped block of contemporaneous faults, and these areas are in favour of the hydrocarbon accumulation because of the fine sand distribution in these structures. The conventional well pattern of the oil development is not effective near the contemporaneous faults as their down-dropped block may be overlooked. The research of the contemporaneous faults shows that the areas near these fault down-dropped block have also the potential prospects of the existence of residual oil.

Karst development and reservoir characterization of Lower Cambrian Shilongdong Formation in Western Hunan-Hubei area

FENG Jufang, LIN Juanhua, TIAN Haiqin, WO Yujin, ZHU Dongya
Science & Technology Review. 2016, 34 (2): 121-128. ;  doi: 10.3981/j.issn.1000-7857.2016.2.019
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Abstract ( 1247 )
Significant gas discovery in the Lower Cambrian Longwangmiao Formation in Sichuan basin has received wide attention on the time-equivalent Shilongdong Formation in Western Hunan-Hubei area. In order to provide guidance to the regional evaluation of reservoir in Western Hunan-Hubei area, detailed research has been carried out with methods including observation of outcrop, thin section, casted thin section, and cathode luminescence analysis. Based on the research of several outcrops in Eastern Hubei-Chongqing and Western Hunan-Hubei area, typical weathering crust karst features have been observed. Miaoliangzi-Dingzhai cross section has been chosen as the typical section in Enshi Xianfeng area for detailed research. The surface karstificated zone is 3 meters in thickness, composed of weathering layer and collapse breccia layer. The underlying strata have been affected by meteoric water leaching and dissolution due to faults and fracture system. And the meteoric water dissolution reaches as far as hundreds meters. According to the cement types and dissolution features, the vertical seepage flow zone and horizontal subsurface flow zone have been distinguished. Lithology is overall dense in the research area, but high quality reservoir with high porosity and permeability exists in some area, especially in the surface karstificated zone. In the vertical seepage flow zone and horizontal subsurface flow zone, pore space is lost due to late silicification, and only minor pore space is preserved. According to the discussion of diagenesis process and reservoir development, high quality reservoir is mainly controlled by supergene karstification, burial dissolution, and dolomitization. It is speculated that regional unconformity karsts are present in the research area, which are related to Xingkai movement during early Cambrian. This research is important to the regional evaluation of reservoir in Eastern Hubei-Chongqing and Western Hunan-Hubei area.

Biomarker characteristics and oil-source correlation of the Yanchang crude oil in Fuxian area, Ordos Basin

LUO Yinshan, ZHANG Shaonan, LUO Xiaoming, DENG Nantao, WANG Li
Science & Technology Review. 2016, 34 (2): 129-134. ;  doi: 10.3981/j.issn.1000-7857.2016.2.020
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Abstract ( 1224 )
Samples of the Mesozoic source rock, crude oil and oil-bearing sands from Fuxian area in the southern Ordos Basin were collected systematically. Gas chromatography-mass spectrometry (GC-MS) was performed on the saturated hydrocarbon fractions extracted from these samples for discussing their biomarker characteristics and crude oil origin. The results show that on the basis of biomarker source parameter distribution, the Mesozoic source rock can be divided into five types (type A1、A2、A3、A4 and B), and the crude oil can be grouped into three types (I, II and III). Type I crude oil is derived from type A1 source rock (Chang 7 oil shale deposited in a reducing, deep lacustrine facies environment). Type II crude oil is sourced from type A2 source rock (Chang 7 dark mudstone deposited in subreducing to reducing, deep or semi-deep lacustrine facies environments). Type III crude oil is sourced from type A3 source rock (Chang 7 dark mudstone deposited in a sub-reducing to reducing, semi-deep lacustrine facies environment).

Geological condition evaluation for establishing gas storage in Pingdingshan salt cavern

CHEN Bo, SHEN Xueming, WANYAN Qiqi, SUN Chunliu
Science & Technology Review. 2016, 34 (2): 135-141. ;  doi: 10.3981/j.issn.1000-7857.2016.2.021
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Abstract ( 1176 )
In this paper, research is taken on the characteristics of fault, structure and salt layer distribution both on horizontal and vertical surfaces in Pingdingshan area, based on previous achievement such as three-dimensional seismic interpretation, drilling well and old well data. The sealing ability of the cap and the mezzanine is assessed by indoor experiment. Through the above comprehensive evaluation on geological condition, the underground gas storage construction is considered feasible. The study shows the followings. Firstly, the overall structure of the study field salt ore is simple with a small amount of faults and a large thickness of salt layer in the center of deposition. Secondly, the salt is thick and the lateral distribution is stable, where the average thickness of 14 to 20 salt groups is more than 200 meters. What's more, the salt ore content is high and the mezzanine number is little. Therefore, the object layer can be chosen to be there for database building. Thirdly, the sealing ability is also good enough to establish the gas storage, as the lithology of cap and mezzanine is mainly mudstone, with small microscopic pore throat in size, poor connectivity and permeability and bad transportation ability of gas.

Formation, sedimentary characteristics and natural gas enrichment control factors in the 3rd member of Xujiahe formation in Yuanba area

JIA Shuang, XIAO Kaihua, LI Hongtao, WEI Xiuping
Science & Technology Review. 2016, 34 (2): 142-146. ;  doi: 10.3981/j.issn.1000-7857.2016.2.022
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Abstract ( 1074 )
This paper analyzes the sequence stratigraphy feature, lithology facies distribution, reservoir features and the distribution and control factors of the 3rd member of Xujiahe formation in Yuanba area, on the basis of the theory of high resolution sequence stratigraphy and core observation results. The target zone has been divided into one long sequence and five short sequences, corresponding to five sand groups. The experimental analysis of cores reveals that the reservoir belongs to low porosity and low permeability tight sandstone reservoir due to its poor physical properties, and this type of tight sandstone reservoir belongs to secondary tight reservoir because the efficient pores were formed during diagenesis procedure. Well test data confirm that the gas wells' productivities are very different and the upper three sand groups of the 3rd member of Xujiahe formation are relatively rich areas for natural gas. However, the distribution of gas in these three sand groups is still not uniform, which indicates that even in the same sand group, the gas performance varies dramatically from well to well. In order to find the reasonable explanation for this phenomenon, we conducted careful calibration between wells and logging curves to identify the reservoir features such as fissures and dissolution pores as well as analysis of influences of microfacies, lithologic belt, and sand body thickness. We draw a conclusion that favorable lithologic belt and sand body thickness are basic conditions for natural gas accumulation, and fissures combined with dissolution pores are key factors.

Effect of nonlinear percolation on recovery factor of low permeability gas reservoirs

WANG Yining, WANG Hui, CAO Shuhui, NI Jun, MEI Shisheng, OUYANG Jingyun
Science & Technology Review. 2016, 34 (2): 147-151. ;  doi: 10.3981/j.issn.1000-7857.2016.2.023
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Abstract ( 1126 )
Non-linear seepage generally exists in the development of low permeability gas reservoirs. It is meaningful to study the effect of non-linear seepage on recovery factors for reasonably exploiting these low permeability gas reservoirs. Cores from the Tarim gas field are adopted and non-linear seepage experiments are conducted under different permeabilities and different water saturations. The experiment results show that low permeability gas reservoirs exhibit a start-up pressure gradient and strong stress sensitivity. The lower the permeability and the higher the water saturation, the larger the start-up pressure gradient, the stronger the stress sensitivity, and the more obvious the non-linear seepage behavior. Non-linear seepage impacts the recovery factor of low permeability gas reservoirs strongly. With the increase of start-up pressure gradient and stress sensitivity, the abandonment pressure of the gas field rises, and the recovery factor declines. During the development and deployment of low permeability gas reservoirs, the area with high permeability and low water saturation should be exploited firstly. Furthermore, well pattern infilling, reservoir stimulation and reducing water saturation are the effective methods to improve the recovery factor of low permeability reservoirs.

Productivity model of fractured gas well considering stress sensitivity in low permeability gas reservoirs

HOU Yong, TANG Rui
Science & Technology Review. 2016, 34 (2): 152-155. ;  doi: 10.3981/j.issn.1000-7857.2016.2.024
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Abstract ( 1133 )
The low permeability gas reservoir exists stress sensitivity due to the tight pore throat, and the gas well is generally fractured before starting production. It is essential to establish the productivity model of gas well considering stress sensitivity in low permeability gas reservoirs. The cores from Tarim low permeability gas field were adopted for stress sensitivity experiments. The experiment results show that the low permeability cores present strong stress sensitivity. With the decline of permeability, the stress sensitivity coefficient rises, and the stress sensitivity becomes strongly. The seepage area of fractured gas well is divided into two parts: One part is the radial flow around the two ends of fractures; The other part is the linear flow along fractures. Then the gas well productivity model considering stress sensitivity is deduced. The stress sensitivity has a significant impact on the productivity of fractured gas well. The stronger the stress sensitivity of gas reservoirs is, the higher the productivity loss rate is. With the decline of flowing bottom hole pressure, the productivity loss increases due to the stress sensitivity. Fracturing is an effective method for improving the productivity of gas well affected by stress sensitivity in low permeability reservoirs.

Characterization and performance evaluation for nano/micron-sized polymer particles flooding agent

LONG Yunqian, ZHU Weiyao, WANG Ming, HAN Hongyan, HUANG Xiaohe
Science & Technology Review. 2016, 34 (2): 156-161. ;  doi: 10.3981/j.issn.1000-7857.2016.2.025
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Abstract ( 1150 )
AM/AA/MMA nano/micron-sized polymer particles are prepared by distillation precipitation polymerization method and characterized using Fourier transform infrared spectroscopy, scanning electron microscopy and laser particle size instrument. The effect of NaCl mass concentration on the hydration expansion property of polymer particles and the effect of hydration time on the migration plugging property of polymer particles are investigated. The oil displacement experiments are carried out in different permeability cores. The experimental results show that AM/AA/MMA polymer particles are regular spherical and the dry particle size is about 500 nm. The polymer particle size gradually increases with the increase of hydration time; But after 200 h, the size of the particle is no longer increased. The expansion ratio of polymer particles decreases gradually with the increase of NaCl mass concentration; when the NaCl mass concentration increases from 5 g/L to 20 g/L, the expansion ratio is reduced by 1.01. The pugging effect of polymer particles on core may enhance with the increase of hydration time; From 24 h to 120 h, the core plugging rate is increased by 40.62%. The injection of 0.5 times pore volume polymer particles solution with 1.5 g/L mass concentration can increase by an average of more than 9% of the recovery rate. With the increase of permeability, the enhanced oil recovery increases gradually. But the enhanced oil recovery will remain constant when the permeability is higher than 50×10-3 μm2.

Influencing factors for particles settling velocity in vertical pipes

ZHAO Guoyan, LIN Chunping, HONG Changshou
Science & Technology Review. 2016, 34 (2): 162-166. ;  doi: 10.3981/j.issn.1000-7857.2016.2.026
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Abstract ( 1186 )
For the issue of "greater well depth" faced by deep mining activities, the influencing factors on the settling velocity of particle in the hydraulic lifting system have been studied. Based on the settlement mechanism of spherical particle in water, the settling velocity expressions of laminar area, transition area and turbulent area are respectively determined. A sensitivity analysis is carried out in terms of particle size, particle density and water temperature, and the influence of particle shape and its concentration on the settling velocity is discussed. The results show that in the laminar area and transition area, the sensitivities of particle size, particle density and water temperature to the settling velocity vary with the ratio of particle density to the water's; That in the turbulent area, the sensitivities of those influencing factors exhibit as particle density >particle size >water temperature; And that the actual settling velocities of irregular particles are less than those theoretical values of the spheroidal particle of same size. To make the results better fit engineering practice, the particle shape factor is employed to amend the differences between the theoretical values and the actual ones, and Richardson-Zaki formula is adopted in the hindered settling process.

A crossing criterion of hydraulic fracture in shale gas reservoir with consideration of stress interference

TIAN Leng, XIAO Cong, LIU Mingjin, GU Daihong, LI Xianglong, SONG Guangyu, DING Daoquan
Science & Technology Review. 2016, 34 (2): 167-172. ;  doi: 10.3981/j.issn.1000-7857.2016.2.027
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Abstract ( 1120 )
Based on the formation mechanisms of stress interference of multi-fractures induced by network fracturing in shale gas reservoirs, this paper establishes a crossing criterion with consideration of remote stress, stress intensity near the tip of fracture and stress interference of multi-fractures. The results of model analysis illustrate that the ability of hydraulic fractures to cross natural fractures decreases under impact of stress interference of multi-fractures; Meanwhile, the net fracture pressure was higher when the fracture was longer, the distance between fractures was shorter, and the natural fracture was closer to the intermediate fracture, leading to larger interference stress between fractures. With decrease of the intersection angle between the hydraulic fractures and natural fractures, the ability of the former to cross the latter decreased within a certain range of stress ratio and friction coefficient, and increased when the stress ratio and friction coefficient were beyond this range. The crossing ability is not affected by the intersection angle under high stress ratios. These results may provide references for practical fracturing stimulation of shale gas reservoirs.

Pipeline transportation of CO2-rich mixture

LI Jiangfei, DUAN Xinghua, LI Yanfang, ZHANG Kang, ZOU Zhenchun, WU Changchun, CHEN Yingchao, LU Guoqiang
Science & Technology Review. 2016, 34 (2): 173-177. ;  doi: 10.3981/j.issn.1000-7857.2016.2.028
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Abstract ( 1094 )
Pipeline transportation is regarded as an economical and effective way to transport CO2. The captured CO2 generally contains such impurities as N2, O2, CH4, Ar, and H2O. The type and content of impurities will impact the properties of CO2-rich mixture and subsequently the flow characteristics. The physical properties of pure CO2 were calculated and analyzed using Matlab based on Span Wagner EOS. Then the uniformly most accurate EOS for CO2-rich mixture was selected by comparing the calculation accuracy of the BWRS, SRK and PR EOS. Based on PR EOS, which has been proved to be the most proper EOS for CO2-rich mixture, a one-dimensional compressible flow model was developed to describe the steady and transient flow characteristics of CO2-rich mixture in the pipeline. Finally, the steady simulation under different flow states (supercritical state, dense phase, liquid state, gaseous state), impurities (type and content), and pipe parameters was conducted. The results show that PR EOS is the most proper EOS for CO2-rich mixture. Compared with gas transportation of CO2 pipeline, the pressure drop of dense phase and supercritical state transportation is relatively small, while the pressure drop of dense phase transportation is the least. Different types of impurities have different effects on broadening the gas-liquid two-phase region of CO2-rich mixture. Compared with that of natural gas pipeline, laws of steady flow of CO2-rich mixture pipeline are revealed, which may provide theoretical guidance for efficient operation and safe control of CO2 pipeline.

A new production operation simulation system and its application to oil companies based on the big data theory

QU Haixu, ZHANG Hujun, CUI Haiqing
Science & Technology Review. 2016, 34 (2): 178-183. ;  doi: 10.3981/j.issn.1000-7857.2016.2.029
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Abstract ( 1204 )
This paper analyzes the demand and the characteristics of oil companies in the big data era on basis of summarizing the background of the big data era. Combining with the information system of the CNPC, the production and operation simulation system of oil companies is developed. The overall framework, the technology roadmap, the data connotation, the function and the application prospect of the upstream business production and operation simulation system on the big data platform are demonstrated. The system will play a demonstrative and instructive role for the business information platform construction of oil companies in the big data era.

An automatic P-and S-wave onset-picking designed for single-component microseismic signals

WANG Liguan, WANG Hui, ZHAO Junjie
Science & Technology Review. 2016, 34 (2): 184-189. ;  doi: 10.3981/j.issn.1000-7857.2016.2.030
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Abstract ( 1285 )
The geophone can daily detect a large amount of microseismic signals and it is time consuming for manual picking the arrival times of P-S waves. We propose an automatic P-and S-wave onset picking method based on single-component geophone, which is widely used in mines. Firstly, we filter the original signal with a Butterworth bandpass filter in order to increase the SNR. The mine microseismic signal frequency ranges from 10 Hz to 2000 Hz, so we choose the band-pass filter interval to be 3-2400 Hz. Secondly, we need to locate the P-S wave phases in the signal. An improved characteristic function can strengthen the change of frequency and amplitude. We define two neighboring windows of different sizes, with the short time window lying in the end of the long time window. Then we compute the average value of the characteristic function within the window, which is also called STA/LTA (short-term average value/long-term average value). With the sliding of the long-short time window, we can get the positions of the P-S wave onset windows. The ratio of STA/LTA will have two peaks because the arrivals of P wave and S wave. Through a preset threshold, we can locate two time windows including P wave onset time and S wave onset time, respectively. In the last step, Akaike's information criterion(AR-AIC criterion) is used in the two time windows, the global minimum of AIC in the window is the arriving time. We have tested this method with one thousand single-component microseismic signals, the result has shown that 71% of P-wave arrival time picking is correct and 79% of S-wave picking is correct.

Research on multi-field coupling process of coalfield fire area development and evolution

MA Li, LIU Geng, XIAO Yang, LU Junhui, HE Yongjun
Science & Technology Review. 2016, 34 (2): 190-194. ;  doi: 10.3981/j.issn.1000-7857.2016.2.031
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Abstract ( 1164 )
Aiming at the multi-field coupling process of coalfield fire area development and evolution, this paper analyzes the thermalhydrological-mechanical coupling mechanism and states together with products of coal combustion in different periods. This paper also reveals the disaster mechanism of development and evolution of coalfield fire area as a series of activities: Heat releasing originated from coal oxygen complex chemical reactions and overlying strata collapse made by burn out area, followed by the fracture network formed by cracks in coal and rock mass, which provide circulation channel for oxygen and combustion products, ultimately the expansion of the fire disaster mechanism extending to the deep. Thus, the coupling of the coal fire thermal hydrological mechanical and chemical field is an accelerating nonlinear dynamic cycle process of coal combustion. The results provide a scientific basis for the prevention and control of coalfield fire.

Heat transfer characteristics of seasonal ventilation and surrounding rock in deep mines

YUE Gaowei, LI Minmin, XU Mengfei
Science & Technology Review. 2016, 34 (2): 195-199. ;  doi: 10.3981/j.issn.1000-7857.2016.2.032
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Abstract ( 1077 )
There exists large seasonal difference in entrance airflow temperature in mine ventilation. This paper tested temperature variation in roadway ventilation in different seasons, and established a mathematical heat transfer model of the surrounding rock and airflow to numerically simulate their heat transfer characteristics. The results show that the airflow exchanges heat with the surrounding rock along its path in the roadway, leading to continuous increase of the airflow temperature, which increases slowly in the working face. The numerical simulation results are consistent with the measured results. The variation of airflow temperature is significantly affected by seasonal difference, and the lower the airflow temperature at the entrance is, the larger the temperature change is under the same airflow distance in the roadway. This study reveals the heat transfer characteristics of mine ventilation and may provide references for ventilation cooling technologies.

Optimization of content determination of monoester-type alkaloids in aconite

ZHANG Chao, YANG Xinxin, LIU Ya'nan, CAI Lu, WANG Shuai, PENG Xue, LI Chaoying
Science & Technology Review. 2016, 34 (2): 200-204. ;  doi: 10.3981/j.issn.1000-7857.2016.2.033
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Abstract ( 1053 )
This paper aims to optimize the method for content determination of monoester-type alkaloids in aconite by HPLC in the Chinese Pharmacopoeia (2010 edition). By comparing the methods mentioned in the Chinese Pharmacopoeia and in the literature, we found that there are defects in the extraction method of samples, preparation methods of sample solution, chromatographic conditions, detection methods and determination results in content determination of monoester alkaloids in aconite by HPLC. Therefore, we established a new determination method and compared it with the one stated in the Chinese Pharmacopeia. The established method had better performance than the previous one. This simple method greatly shortened the testing time, reduced the cost, and improved column efficiency, providing a safe, effective, and quality-controllable detection method for aconite.

Corrosion behavior of new low alloy corrosion resistance rebar

LIU Ming, CHENG Xuequn, LI Xiaogang, XING Pei, HONG Yuanyuan, WEI Zibo
Science & Technology Review. 2016, 34 (2): 205-209. ;  doi: 10.3981/j.issn.1000-7857.2016.2.034
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Abstract ( 993 )
The electrochemical methods of the potentiodynamic polarization, the electrochemical impendence spectroscopy and the dry/wet cycle corrosion test are employed to investigate the corrosion behavior of the Cr modified HRB400 carbon steel rebar in 0.01 mol/L NaHSO3 solution. The open circuit potential of the Cr modified steel shifts in the positive direction as compared with the HRB400 carbon steel; The results of the polarization curve show that the corrosion current density of the Cr modified steel is decreased, the polarization resistance is increased and the corrosion rate is declined. After the dry/wet cycle corrosion test for 72 h, the corrosion morphologies of the HRB400 steel and the Cr modified steel see a uniform corrosion, the addition of the Cr element can significantly reduce the corrosion rate of the HRB400 steel rebar.

Optimization of mix proportion of paste based on uniform design

AI Chunming, WU Aixiang, WANG Hongjiang, LIU Sizhong
Science & Technology Review. 2016, 34 (2): 210-214. ;  doi: 10.3981/j.issn.1000-7857.2016.2.035
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Abstract ( 870 )
The retarding phenomenon appeared in the paste filling of a lead-zinc mine and it was ameliorated after adding coagulants. To optimize the paste material ratio under addition of coagulants, we carried out a uniform design experiment. The effects of paste concentration and sand-cement ratio on bleeding rate, fluidity, backfill gradient and paste strength were investigated. The results show that the paste bleeding rate, fluidity and backfill gradient were mainly influenced by concentration, and they were negatively correlated with the concentration. The sand-cement radio had a small impact on fluidity but a major impact on paste concentration. The smaller the sandcement ratio was, the larger the intensity of paste was. Based on the ratio ranges corresponding to the four indices of bleeding rate, fluidity, backfill gradient, and paste strength, the recommended ratio is 75% to 76% and the sand-cement ratio is 7:1 to 8:1.

Molecular cloning and sequence analysis of sodium-bile acid cotransporter from Echinococcus granulosus in Xinjiang, China

YANG Mei, LIANG Xiaodi, LI Jun, LI Liang, ZHANG Fuchun, ZHANG Wenbao
Science & Technology Review. 2016, 34 (2): 215-220. ;  doi: 10.3981/j.issn.1000-7857.2016.2.036
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Abstract ( 292 )
Sodium-bile acid cotransporter (EgSBACT) functions in the sodium-bile acid transportation in Echinococcus granulosus (Eg) Protoscolex and the sequence is unknown. The specific primers for EgSBACT mRNA are designed and the EgSBACT gene is amplified by RT-PCR from Eg protoscolex total RNA. Then the EgSBACT gene fragment is cloned into pET30a vector which is a prokaryotic expression vector for sequencing and analyzing by bioinformatics method. The PCR products of EgSBACT is about 650 bp whose length is 654 bp and encodes a protein containing 217 amino acids and the pI of this protein is predicted as 9.28. Homology analysis shows that there is 43% of similarity between EgSBACT and the trematode SBACT (GenBank: GAA57409.1). Phylogenetic analysis shows that EgSBACT is clustered with Fluke, and has a lower homology to other species. EgSBACT gene is cloned from protoscolex of Echinococcus granulosus in Xinjiang, which lays a foundation for further study of EgSBACT function in the development and differentiation of PSCs into adult worms. This research provides a way to express the EgSBACT protein in vitro and taking advantage of this protein further research can reveal the exact functions of EgSBACT in the sodium-bile acid transportation in Echinococcus granulosus.

Effects of TGF-β1 on myocardial fibrosis due to different reasons

DING Wenjin, AO Bifeng, OUYANG Weiwei, SU Shengfa, LU Bing
Science & Technology Review. 2016, 34 (2): 221-225. ;  doi: 10.3981/j.issn.1000-7857.2016.2.037
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Abstract ( 248 )
Myocardial fibrosis (MF) is a complex pathological process, involving multiple systems, many different mechanisms and a variety of cytokines. Among those cytokines transforming growth factor β1 (TGF-β1) is an important pro-fibrotic factor. In the pathological conditions by classical TGF-β1/smads pathways myocardial fibrosis may be induced and developed eventually to heart failure. In this paper, high blood pressure, diabetes, radiation damage and viral myocarditis mechanisms leading to MF are reviewed, with a focus on the role of TGF-β1 signaling pathway in the MF, so as to provide more specific and effective targets for the prevention and treatment of myocardial fibrosis and heart failure due to different reasons.

Genetic characteristics of Uyghur from different sample locations in Xinjiang

ZHOU Canlin, MA Qi, YAO Hua, WANG Li, WANG Tingting, MA Yan, SU Yinxia, WANG Zhiqiang, CHEN Kaixu
Science & Technology Review. 2016, 34 (2): 226-230. ;  doi: 10.3981/j.issn.1000-7857.2016.2.038
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Abstract ( 192 )
To understand the genetic characteristics of Uyghur, 300 Uyghur that were born before 1955 were collected from 10 Uyghur residence locations for generations, and 30 SNP loci were employed for genetics research. Bayesian analysis was applied for their genetic structure by STRUCTURE 2.1. The results show that it was reasonable to divide the Uyghurs in Xinjiang into seven groups. UPGMA method was used for phylogenetic research by MEGA 5 based on the Fst date form between different regions in Xinjiang. Both results show that each population from 10 locations was different except those from Urumqi and Ili, Turpan and Attash, and Hami and Kashgar. In other words, almost every population of the Uyghurs in Xinjiang was independent from the genetic view, and this phenomenon may be explained by the historical effect of the silk road and geographic factors.

Isolation of a para-nitrophenol degrading bacterium and characterization of its plant growth-promoting properties

REN Hejun, WANG Cong
Science & Technology Review. 2016, 34 (2): 231-236. ;  doi: 10.3981/j.issn.1000-7857.2016.2.039
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Abstract ( 270 )
A para-nitrophenol (PNP) degrading strain, named PN-1, was isolated from the PNP-contaminated soil. PN-1 utilized PNP as the sole carbon and nitrogen source during the cultivation. Based on the result of 16S rDNA gene sequence, the strain was preliminarily designated as Pseudomona. Experiments were carried out to investigate the degradation of PNP, heavy metal, antibiotic, plant growthpromoting (PGP) properties and GFP-tagging of PN-1. The results showed that the maximum tolerant dose of TM to PNP was 200 mg/L, and the MICs for the following four heavy metals were 700 mg/L for Cd2+, 500 mg/L for Pb2+, 800 mg/L for Zn2+, and 100 mg/L for Cr6+. What is more, PN-1 could grow in media with chloromycetin and ampicillin. PGP traits of PN-1 included IAA, siderophore production, ACC deaminase activity and phosphate solubilizing activity. GFP-tagged PN-1 could survive and bioremediate PNP-contaminated soil with plants.

Enhanced denitrifying phosphorus removal to treat low carbon source sewage in sequencing batch moving bed biofilm reactor

ZOU Donglei, LI Ping, YANG Zhuoyue, DING Wei, ZHANG Haojie, LIU Meijun
Science & Technology Review. 2016, 34 (2): 237-240. ;  doi: 10.3981/j.issn.1000-7857.2016.2.040
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Abstract ( 198 )
SBMBBR is used to investigate the performance of denitrifying phosphorus removal from the low carbon source sewage. The effects on denitrifying phosphorus removal of the COD, the pH in the anaerobic process and the NO3--N, NO2--N in the anoxic stage are studied. The results show that the removal rates of the COD, the NH4+-N, the TP are more than 95%, 90%, 90%, the effluent concentrations are 8.07, 3.67, 0.46 mg/L in the operation of a cycle of 8 h, and the urban sewage A standard is satisfied. Compared with NO2--N as the electron acceptor, NO3--N of 60 mg/L as the electron acceptor can achieve the best result of the anoxic phosphorus absorption. More than 20 mg/L of NO2--N will inhibit the activity of denitrifying phosphorus removal bacteria. The researches show that the denitrifying phosphorus removal can achieve good results when NO3--N is used as the electron acceptor in the SBMBBR.

Phytoremediation of cadmium/zinc contaminated agricultural soil by long term application of sewage sludge manure using Sedum plumbizincicola

GAO Wenya, DENG Lin, LI Zhu, WU Longhua, LIU Hongyan, LUO Yongming
Science & Technology Review. 2016, 34 (2): 241-246. ;  doi: 10.3981/j.issn.1000-7857.2016.2.041
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Abstract ( 189 )
To compare with the conventional maize-wheat-carrot crop rotation model, a two-year field plot experiment of planting Sedum plumbizincicola, cadmium and zinc hyperaccumulator,has been carried out to study the safe agricultural production and repeated phytoremediation efficiency of a Zn/Cd contaminated soil as resulted from long-term application of sewage sludge containing manure. The results show that crops and S. plumbizincicola grow well in the soil under long-term application of sewage sludge manure. Compared with the control, the Zn and Cd concentrations in corn-wheat-carrots crop rotation system are all increased, but the Cd concentrations in wheat and carrots exceed and fail to meet the National Food Quality Standard. The Zn and Cd concentrations in soil under S. plumbizincicola treatments decreas markedly. The phytoremediation efficiency of Cd by S. plumbizincicola is 56.0%, while for the treatment of“continuous application of sewage sludge manure”, the phytoremediation efficiency is still as high as 48.4%. So under conditions of application of sewage sludge, planting with S. plumbizincicola and corn, the triple objectives of safe handling of sludge, promoting crop growth, and high phytoextraction efficiency could be achieved altogether.

Analysis on influence factors of soil organic carbon density using a geographically weighted regression model

LI Long, YAO Yunfeng, QIN Fucang, ZHANG Meili, GAO Yuhan, CHANG Weidong
Science & Technology Review. 2016, 34 (2): 247-254. ;  doi: 10.3981/j.issn.1000-7857.2016.2.042
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Abstract ( 186 )
This research was conducted in Huanghuadianzi watershed in Aohan Chifeng, Inner Mongolia. The influence factors of soil organic carbon density were mainly divided into human factors and natural factors; altitude, slop, normalized differential vegetation index (NDVI) and the shortest distance from path or the village (DIST) were selected as the influence factors. Based on field data samples of the study area, both remote sensing and geographic information system were applied. A geographically weighted regression model was used to study the spatial variations of soil organic carbon density and the different environmental factors. The results showed that the soil organic carbon density changed in the study area from 1.91 to 16.63 kg/m2, with an average density 7.42 kg/m2. The influence degrees of soil organic carbon density in different driving factors ranked as altitude >slop >NDVI >DIST. The influence of each factor on the soil organic carbon changed with spatial difference. Altitude and slope respectively showed a positive and negative correlation with soil organic carbon density. In general soil organic carbon density decreased with the increasing of altitude and slope in most of the study area and the correlation coefficients were -0.436 and -0.223, while positive effect were only in a few areas. On the other hand, the NDVI and DIST showed a positive correlation with soil organic carbon density, with the correlation coefficients of NDVI being from 1.37 to 1.45 and DIST being from 0.15 to 0.47. In order to analyze the spatial variation of each influence factor, a map of the regression coefficient distribution of the environmental factors and soil organic carbon density in the study area was provided, which provided a scientific basis for the efficient utilization of soil and the development of precision agriculture according to the local conditions.

Hazard assessment of geological disaster after "4·20" earthquake in Lushan County

CHEN Li, CHEN Tingfang, ZOU Qiang
Science & Technology Review. 2016, 34 (2): 255-259. ;  doi: 10.3981/j.issn.1000-7857.2016.2.043
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Abstract ( 174 )
After the "4·20" earthquake in Lushan County, secondary geological disasters such as landslides, collapses and debris flows occurred frequently. There are 365 new geological hazard spots which seriously impact local economic construction and post-disaster reconstruction. This paper selects lithology, fault zone, slope, relative elevation, annual rainfall, peak ground acceleration, and the type of land use based on geological disasters environmental conditions to build up a geological disasters hazard evaluation methodology of entropy, which has been applied to Lushan's geological disasters risk assessment. The results show that 49.89% of Lushan's area belong to a medium and high dangerous region, among which 29.99% are in high dangerous region situated in Zheng River, Yuxi River and Lingguan River drainage basin. Impacted by terrain, human activities and earthquake, the geological disasters always damage heavily, so we should pay more attention to it during subsequent construction and disaster prevention and mitigation.

Stress and deformation response in reinforced concrete beam under static and dynamic loads based on meshless method

LIN Hang, XIONG Wei, HUANG Liang, LIU Qunyi
Science & Technology Review. 2016, 34 (2): 260-264. ;  doi: 10.3981/j.issn.1000-7857.2016.2.044
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Abstract ( 409 )
The nonlinear large deformation has always been a difficulty in the numerical analysis of reinforced concrete beams, and the mesh distortion will greatly reduce solution accuracy in the finite element method (FEM), while grid points in the meshless method are not constrained by the grids, so this method can well handle the nonlinear large deformation problem in reinforced concrete beams. To solve the problem of nonlinear large deformation accurately, we establish a numerical model of reinforced concrete beam on the basis of the meshless method, and the static and dynamic loads are applied on the model to analyze the stress, deformation and failure mode of the reinforced concrete beam. The results show that either under the static or dynamic loads, the maximum stress varies with the change of load, and the stress and deformation of the reinforced concrete beam are consistent with the actual law, demonstrating the meshless method can be used for the nonlinear large deformation problem.

Effects of connections of exposed steel anchor boxes on the mechanical behavior of pylon anchorage system

LU Wenru, ZHAO Yi, ZHAO Min, TAN Donglian
Science & Technology Review. 2016, 34 (2): 265-270. ;  doi: 10.3981/j.issn.1000-7857.2016.2.045
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Abstract ( 142 )
This paper aims to study the mechanical characteristics and load transfer mode of pylon anchor system with steel anchor boxes. Taking the north navigable bridge of Hangzhou Bay cross-sea bridge as an example, we analyzed the mechanical behavior and cable force distribution pattern influenced by the connections of steel anchor boxes using finite element analysis (ANSYS 11.0). The results show that when the connection of the steel anchor box is transformed, the transferring force of the anchorage segment and its components are changed slightly, the vertical force transmitted by the anchorage segment has no change, while the vertical force transmitted by the steel anchorage box and pylon wall are changed evidently. Whether the steel anchor box is connected has a great influence on the distribution laws of the stress on the steel plate and concrete pylon wall and the shear force on studs. The stress on the steel plate and concrete pylon wall and the shear force on studs are more evenly distributed in connected steel anchor boxes than those in separated ones. The stress distribution pattern of the side plate and diaphragm are impacted slightly by the connection of steel anchor boxes, while that of the end plate and pylon wall are impacted significantly.

An analytical method for jacking force of middle span closure for high pier and long-span continuous rigid frame bridge

YANG Guojun, HAO Xianwu, DUAN Ruifang, LI Ziqing
Science & Technology Review. 2016, 34 (2): 271-276. ;  doi: 10.3981/j.issn.1000-7857.2016.2.046
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Abstract ( 175 )
In order to determine the jacking force of middle span closure for the high-pier and long-span continuous rigid frame bridge reasonably, an analytical method for jacking force of continuous rigid frame bridge with single pier under closure sequences is developed based on the force method. Taking the construction work of a three span continuous rigid frame bridge as an example, the jacking force and displacement of the middle span closure are calculated by the analytical method, then numerical simulation method is applied to establish the finite element model. The jacking force and displacement are calculated and compared with the principle of eliminating the horizontal displacement of pier top caused by the five-year shrinkage and creep of concrete and closure temperature difference. Monitoring records in practical engineering have shown that the calculating results by the proposed analytical method are basically the same as those by the finite element method (FEM) and the real measurements, and that the error between calculating results by the analytical method and FEM is less than 10%, which indicates that the analytical method has a relatively high calculation accuracy and can meet the requirement of practical engineering.

Load effect analysis of PC slab bridges under extra-heavy trucks

HAN Wanshui, ZHAO Shiliang, LI Yanwei, ZHAO Fu'an, LIU Libin, YUAN Yangguang, LIU Xiangru
Science & Technology Review. 2016, 34 (2): 277-281. ;  doi: 10.3981/j.issn.1000-7857.2016.2.047
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Abstract ( 92 )
For the purpose of studying the load effect of PC slab bridges under extra-heavy trucks, 883 extra-heavy truck scenarios were extracted based on WIM data from Xuanda highway in Hebei Province. The "bridge dynamic analysis system" was used to calculate the most unfavorable sagging moment of each slab and the maximum sagging moment effect of the bridge. The lateral performance of the slabs was investigated using statistics about the most unfavorable sagging moment of each slab. In addition, the overrun of sagging moment of PC slab bridges was analyzed based on comparison of the maximum sagging moment effect and design value. The results show that owing to the apparent distribution characteristics of extra-heavy trucks, the extreme unfavorable sagging moment of slab 1 was the highest, and the average unfavorable sagging moment of slab 5 was the highest. Under extra-heavy truck load, the overrun problem of sagging moment was universal. Besides, the maximum sagging moment of some scenarios was 1.8 times of the design value. Both the quantity of overrun scenarios and overrun level decreased slightly with the increase of bridge span.

Weibo topic detection based on improved TF-IDF algorithm

CHEN Shuoying, JIN Zhensheng
Science & Technology Review. 2016, 34 (2): 282-286. ;  doi: 10.3981/j.issn.1000-7857.2016.2.048
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Abstract ( 349 )
The topic detection and tracking (TDT) is an issue of natural language processing, which concerns with solving the problem of information explosion. The Weibo TDT is a central issue in recent years. A bad performance is usually achieved for Weibo with a short text, while the topic detection of a long text is widely used in the industry with better results. Weibo's features of short text and not very clear meaning make the clustering algorithms' effect not ideal in topic detection. So this paper focuses on finding a new way to improve the effect of clustering for Weibo. Weibo features fast renewal and strong timeliness. Hot topics produced by Weibo show burstiness, and their representative words increase in a great extent. With this feature in mind, improving the representative word's weight to a certain degree is a good way to give a prominence to the feature of short text. The burstiness of the words is a thing to consider, similar to the kinetic theory of the object. The formula of the kinetic energy theorem is used in this paper. Then an improved feature extraction algorithm named the TFIDF-KE (term frequency-inverse document frequency-kinetic energy) is proposed. The new algorithm consists of the kinetic energy and the TF-IDF (term frequency-inverse document frequency). The formula of the kinetic energy theorem is used to evaluate the burstiness of the words and add the value to the formula. Then, the weight of some important words can be improved when extracting features. Finally, the implementation of the CURE (clustering using representatives) algorithm completes the Weibo topic detection task. The method presented in this paper describes burstiness of text and feature and solves the problem that the feature of bursty hot topics is not obvious, when clustering in a certain extent. The experimental results show that the method can effectively improve the effect of topic detection in some degree and a better accuracy rate P can be achieved, as well as the R and F values of the recall rate. So TF-IDF-KE is an effective optimization method and can well be used for the task of the TDT.

Hydro-dynamics theory for long-rod projectile penetrating semi-infinite target: reviews and studies

GAO Guangfa,
Science & Technology Review. 2016, 34 (2): 287-298. ;  doi: 10.3981/j.issn.1000-7857.2016.2.049
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Abstract ( 231 )
Taking the behavior of long-rod projectile vertically penetrating semi-infinite metal target as the subject, this paper deduces and reviews a series of modified penetration theories based on the hydro-dynamic theory of penetration (HTP). A large quantity of published experimental data and numerical simulation results are employed for discussion of the theoretical analysis results. The assumptions and premises for the establishment of HTP model are presented. Based on these experimental data, the numerical results and theoretical analysis results, the connotation, scope of application and limitation of HTP model are discussed. The nine application preconditions for the HTP model are proposed. If the strength of the target is taken into account, the Allen-Rogers model is available. On the basis of analysis of the Allen-Rogers model and considering the strength of the projectile, this paper developed a modified Allen-Rogers model, provided solutions for it and made comparative analysis. In view of the deceleration of the projectile in the process of penetration, the numerical simulation of the penetration was conducted. The derivation and evolution of the theoretical model from the modified Allen-Rogers model to Alekseevskii-Tate model are discussed.

Control system for AC/DC hybrid microgrid interface convertor based on SMC

SU Xiaoling, HAN Minxiao, Josep M. Guerrero, ZHAO Xin
Science & Technology Review. 2016, 34 (2): 299-304. ;  doi: 10.3981/j.issn.1000-7857.2016.2.050
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Abstract ( 196 )
This paper first analyzes the AC/DC hybrid microgrid operating characteristics and the mathematical model of the interface convertor according to the operation mode. Then it develops a control system for the interface convertor based on sliding-mode control (SMC). A reaching law is designed to ensure the performance of this control system. An experimental setup is developed based on dSPACE 1006. Simulation and experimental results illustrate that the control system is insensitive to parametric uncertainty or external disturbances. The fast dynamic response and robust control performance of the interface convertor can ensure the stable operation of the microgrid.
Report

Science & Technology Review. 2016, 34 (2): 305-306. ;  doi: 10.3981/j.issn.1000-7857.2016.2.051
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Abstract ( 129 )
Focus

Biosafety issue on researches and applications of Synthetic Biology

LIANG Huigang, HUANG Cui, SONG Donglin, CHEN Zongsheng, YUAN Zhiming
Science & Technology Review. 2016, 34 (2): 307-312. ;  doi: 10.3981/j.issn.1000-7857.2016.2.052
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Abstract ( 626 )
Synthetic biology refers to artificial design and construction of genetic parts and biology systems, which is based on genetic engineering of systematic biology. We firstly review the development status of synthetic biology, the ethical issue, and the safety issue it may cause to the environment and public health. Europe and America support the development of synthetic biology while continuing to improve their management mechanisms. In view of the fact that domestic synthetic biology is still in its infancy, we recommend some corresponding countermeasures in the development of systematic biology based on the lessons from others countries, including strengthening risk assessment in the application and research of synthetic biology, improving supervision and management systems, strengthening biosafety and bioethics education, and promoting exchanges with the international community.

Comparative analysis of railway energy consumption between China and other countries

WU Xiaoping, LI Yusi, LIU Jiangwei
Science & Technology Review. 2016, 34 (2): 313-317. ;  doi: 10.3981/j.issn.1000-7857.2016.2.053
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Abstract ( 647 )
The railway energy consumption accounts for a major portion of the total energy consumption in the world. Because of the difference of the railway development level and national conditions,the characteristics of the railway energy consumption are different in different countries. According to the analysis of the railway consumption in representative countries and associated railway energy situations, a conclusion is drawn that, the railway energy consumption and the passenger/freight traffic volume are directly related to the energy consumption intensity. It is important in the railway transportation to use the limited energy to transport more passengers and freight. In order to reduce the railway energy consumption, it is necessary to improve the railway technical equipment and the traction proportion of electric locomotives, the transport organization and the transport organization forms.

Local dynamics of social balance in the triangle-growing networks

LIU Wei
Science & Technology Review. 2016, 34 (2): 318-322. ;  doi: 10.3981/j.issn.1000-7857.2016.2.054
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Abstract ( 780 )
A network with a large number of triangular relations, whose cluster coefficient could be controlled, was constructed in this study. The local dynamics of social balance in the triangle-growing networks was studied through computer simulations. The results show that the statistical features of the networks are approximately the same as the complete graph when the adding-link probability pa≥0.5, and the evolution of the social balance is independent on the initial conditions; moreover, the system undergoes a dynamic phase transition when the transition probability p≥1/2. However, when the network is sparse, i.e. pa<0.5, the final state of the system depends on the initial state and the system does not experience the dynamic phase transition.
Scientific Community Promotion

Science & Technology Review. 2016, 34 (2): 325-325.
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Abstract ( 669 )
Perspectives

Science & Technology Review. 2016, 34 (2): 326-326.
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Abstract ( 430 )
Scientists

Science & Technology Review. 2016, 34 (2): 327-327.
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Abstract ( 573 )
Careers

Science & Technology Review. 2016, 34 (2): 328-328.
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Abstract ( 768 )
Special Column of Science

Science & Technology Review. 2016, 34 (2): 329-330.
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Abstract ( 444 )
Book Reviews

Science & Technology Review. 2016, 34 (2): 331-331.
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Abstract ( 609 )

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