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   Science & Technology Review
2014, Vol.32, No. 14
18 May 2014

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Science & Technology Review. 2014, 32 (14): 0-0.
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Science & Technology Review. 2014, 32 (14): 1-1.
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Science & Technology Review. 2014, 32 (14): 11-11.
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Science & Technology Review. 2014, 32 (14): 84-84.
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Science & Technology Review. 2014, 32 (14): 87-87.
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Science & Technology Review. 2014, 32 (14): 88-88.
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Science & Technology Review. 2014, 32 (14): 89-89.
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Science & Technology Review. 2014, 32 (14): 89-89.
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Science & Technology Review. 2014, 32 (14): 6-6.
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Science & Technology Review. 2014, 32 (14): 8-8.
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Science & Technology Review. 2014, 32 (14): 10-10.
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Science & Technology Review. 2014, 32 (14): 12-12.
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Science & Technology Review. 2014, 32 (14): 13-13.
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Science & Technology Review. 2014, 32 (14): 14-14.
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Science & Technology Review. 2014, 32 (14): 85-85.
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Science & Technology Review. 2014, 32 (14): 86-86.
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Science & Technology Review. 2014, 32 (14): 90-92.
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Science & Technology Review. 2014, 32 (14): 93-95.
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Articles

Adsorption Behavior of Citric Acid Modified Soybean Straw for Cu2+

ZHANG Ruzhuang, ZHOU Yanbo, GU Xiaochen, LU Jun
Science & Technology Review. 2014, 32 (14): 15-18. ;  doi: 10.3981/j.issn.1000-7857.2014.14.001
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Abstract ( 411 )
Soybean straw (SS) was modified with citric acid (CA) to prepare a new adsorbent (CA-SS) to study the heavy metal adsorption efficiency of SS. The morphological and chemical characteristics of the adsorbent were evaluated through SEM and FTIR analysis. The copper ion (Cu2+) adsorption capability of SS and CA-SS were compared, the effects of initial Cu2+ concentration, contact time and competitive ions were studied, and the adsorption dynamics and thermodynamicswereanalyzed. The results show that the porous structure of SS was preserved after modification, but the carboxyl groups were introduced onto SS. The pseudo-second-order model and Langmuir equation were suited to describe the dynamics and thermodynamics data. The maximum adsorption capacity increased from 10.44 mg/g to 19.14 mg/g according to the Langmuir model. The reason for the increase was that the introduced carboxyl groups increase the net negative charge on the SS, thereby increasing its binding potential for metal ions. Furthermore, Cu2+ exhibits better competiveness than Ni2+; the competitive adsorption in the binary system is related to the chemical properties of each element. CA-SS may be used as a lowcost alternative adsorbent for the decontamination of metal-containing effluent.

Application of SBA-15 Immobilized Ionic Liquid in Hydrolysis of Propylene Carbonate

GUO Jianping, TANG Binyan, CHEN Xin, ZENG Hailang, MAO Liqiu
Science & Technology Review. 2014, 32 (14): 19-23. ;  doi: 10.3981/j.issn.1000-7857.2014.14.002
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Abstract ( 294 )
With introduction of basic groups in the imidazole cation, the imidazole functional ionic liquid with an alkaline site was synthesised, which was immobilized on mesoporous molecular sieve SBA-15, and functionalized triethylamine immobilized ionic liquid material was obtained. The catalyst was characterized by FT-IR, TG-DTG, X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption methods. Analysis by characterization showed that the immobilized catalyst surface area, pore volume and pore diameter decreased compared with those of pure silica SBA-15. The catalytic activity of the catalyst was investigated in the hydrolysis reaction of propylene carbonate, under conditions of enough water, reaction temperature of 140℃, the amount of catalyst 3%, and reaction time 2 h, where the best catalytic effect was obtained. The selectivity and yield were more than 99%, and the catalyst was reusable.

Attenuation Mechanism of Parsley Rotten Root Extract on Fusarium oxysporum f. sp. cucumerinum

LI Jie, YUN Xingfu, GAO Xiaomin, WANG Yong, QIAN Cheng, MA Liguo
Science & Technology Review. 2014, 32 (14): 24-30. ;  doi: 10.3981/j.issn.1000-7857.2014.14.003
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Abstract ( 285 )
This paper investigates the attenuation mechanism of parsley rotten root extract on Fusarium oxysporum f. sp. cucumerinum (Foc.). Foc. was treated from the first to fifth generation with parsley rotten root extract prepared by ethanol, acetone, and distilled water. The excretive fusarium acid content and cell wall degradation enzyme activity were detected and their correlation with pathogenicity was studied. The results show that the pathogen's fusarium acid content and pectinase enzyme activity were significantly reduced with the increase of treated generations, the cellulose enzyme activity had no apparent change with the increase of treated generations, and the β-glycosidase enzyme activity increased with the increase of treated generations, but all were lower than those in the control group. Correlation analysis shows that there are significant or extremely significant positive correlation between pathogenicity and the pathogen's fusarium acid content, pectinase enzyme activity, and β-glycosidase enzyme activity, but there is no clear relationship between pathogenicity and the cellulose enzyme activity.

DNA Preparation of Toxigenic Aspergillus and PCR Detection of aflR Toxin Gene

JIANG Dan, JIN Weilin, SU Deshan, HUANG Yaojiang
Science & Technology Review. 2014, 32 (14): 31-34. ;  doi: 10.3981/j.issn.1000-7857.2014.14.004
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Abstract ( 292 )
This paper discusses the modified CTAB method for DNA extraction of toxigenic Aspergillus and compares it with the kit extraction method. The modified CTAB method successfully extracted DNA of toxigenic Aspergillus. The concentration and purity reached the standard of PCR amplification. Two pairs of primers were designed based on the aflR gene for aflatoxin biosynthesis regulation, and the toxigenic Aspergillus aflR gene was identified by using PCR amplification. The results show that the aflR gene is contained in the genome of Aspergillus flavus, Aspergillus parasitic and Aspergillus tamarii, Aspergillus fumigates and Aspergillus versicolor are not detected, realizing the purpose for identifying aflatoxin producing strains. This method provides a reference for rapid detection of toxigenic fungi.

Single and Double Energy Conversion of Geothermal Power Generation

LUO Chao, MA Weibin
Science & Technology Review. 2014, 32 (14): 35-41. ;  doi: 10.3981/j.issn.1000-7857.2014.14.005
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Abstract ( 181 )
Geothermal power is an important renewable energy source. China possesses complex geological conditions and geothermal resources. For better utilization of this energy, the performance of single and double geothermal power systems including single and two-stage flash system, binary power system and flash-binary power system is analyzed and compared on the basis of numerical calculation. The results show that the performance of direct cooling system is better than that of indirect cooling system; the power output of double energy conversion system is higher than that of single system. Double energy conversion system is a better choice when the geothermal temperature is high. The optimum flash temperature of the flash-binary system is higher than that of other systems, which is helpful to reducing equipment volume and keeping appropriate system pressure. The results of this study provide theoretical basis and simulation verification for applications of geothermal energy.

Impact of Water/CO2-Rock Interactions on Formation Physical Properties in EGS

BAO Xinhua, WU Yongdong, WEI Mingcong, JIN Xianpeng, WANG Shuyuan
Science & Technology Review. 2014, 32 (14): 42-47. ;  doi: 10.3981/j.issn.1000-7857.2014.14.006
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Abstract ( 392 )
The enhanced geothermal system (EGS) is an engineering technique that has been created to extract economical amounts of heat from geothermal resources of low permeability and porosity. After the heat-exchange fluid is injected into the deep geothermal reservoir, there will be a water-rock interaction in the fracture channel, causing the dissolution and precipitation of reservoir minerals and changing the physical properties of the fracture channel, influencing long-time running of EGS significantly. This paper concerns a typical granite in Soultz as a geothermal reservoir and builds up a one-dimensional MINC model. Then CO2 and water with identical temperatures and pressures are injected to contrast the effects of injected fluid water/CO2-rock interactions on the fractures in EGS. Results show that the effect of water-rock interaction of CO2-EGS on fracture channel properties is less obvious than that of H2OEGS on the same operation mode.

Application Research of Unascertained Clustering Theory in Prediction of Roof Settlement

LI Qiyue, ZHANG Ruihua, MA Shaowei, WU Zhibo, MA Chunde
Science & Technology Review. 2014, 32 (14): 48-53. ;  doi: 10.3981/j.issn.1000-7857.2014.14.007
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Abstract ( 152 )
The confidence criterion of the unascertained clustering theory is optimized on the basis of distance discriminant method, then this theory is applied to the prediction of roof settlement. Firstly, nine factors of roof settlement, such as the tensile strength of rock mass, stope depth, and exposed area, are selected to establish the model for unascertained clustering prediction. Then the unascertained measurement function is obtained based on fifteen groups of sample data, and the index weights of each factor are calculated by entropy theory. Finally, the results of the classification grade and prediction of roof settlement are obtained. According to the computing validation, the average prediction error of this method is controlled within 7.38%, which is improved greatly compared with other three methods including the fuzzy mathematics method, the grey relation method and the neutral network method. Taking Woxi mining area of Chenzhou mine for example, this optimized method is applied to the prediction of roof settlement of No.4142 stope in order to further inspect its practicability. The results show that the prediction results are consistent with the actual situation, and that the optimized method of roof settlement prediction is objective and reasonable and can provide a decision-making basis for the safety production on mine.

Proppant Embedment Model of High Rank Coal

ZHANG Suian, CAO Lihu, TAN Yangjun, LIU Yan, WANG Wei, HUANG Zhaoxin
Science & Technology Review. 2014, 32 (14): 54-58. ;  doi: 10.3981/j.issn.1000-7857.2014.14.008
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Abstract ( 271 )
The successful development of coalbed methane in China is essential to national energy security, coal mining safety and the environment. Creating high conductivity fracture within coal matrix using hydrofracture has been regarded as one of the most effective technologies for coalbed methane development. As a complicated procedure, however, the ability to create fractures with high conductivity is significantly influenced by flowing back, smashing and embedding of the proppant, which can be well represented by the operations in the study area Qinshui basin. The proppant is easily embedded into the surface around the fracture during hydrofracture in highly matured soft coal in Qinshui basin. Hence, conductivity of the generated fracture is dramatically reduced as a result of narrow fracture with embedded proppant. Currently, studies on proppant embedding are mainly conducted in physical experiments, lacking the corresponding numerical models. To analyze the influence of closure pressure and Protodyakonov coefficient on proppant embedding in a numerical method, width formulas and embedded pressure formulas for coal were deduced based on Langmuir law. Experiments for examining the model have been conducted as well. The results show that there is a critical pressure during insertion of the proppant into the coal surface. The smaller the protodyakonov coefficient is, the lower the critical pressure becomes, and the easier the insertion of the proppant is. When the closure pressure was lower than 30 MPa, and only half or even less of the proppant was inserted into the coal, relatively high similarity was obtained between the calculated results from the numerical model and the experimental results. Thereby, the deduced width formulas and embedded pressure formulas are valuable in the hydrofracture design for the high rank coal in Qinshui Basin.

Electrostatic Voltage Test of Coal Mine Gas Drainage Pipeline of PVC

YUE Gaowei, XU Mengfei, BI Wei
Science & Technology Review. 2014, 32 (14): 59-63. ;  doi: 10.3981/j.issn.1000-7857.2014.14.009
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Abstract ( 294 )
Electrostatic discharge caused by strong electrostatic voltage due to charge accumulation on the PVC pipe wall has potential damages to coal mine gas drainage. In this paper, a set of device is built to test the electrostatic voltage of the PVC pipe during coal mine gas drainage process, and effective ignition energy of electrostatic discharge is calculated. The test results show that with variation of the gas flow velocity, PVC pipe diameter, and gas concentration, the electrostatic voltage of the PVC pipe increases gradually with time at the beginning, and then tends to be stable. Due to friction between the gas and PVC pipe wall, charge accumulation on the wall causes strong electrostatic field of more than 20 kV/m. With the minimum ignition energy of 0.28 mJ for methane taken as the standard, the effective ignition energy for electrostatic discharge in PVC pipe is usually less than 0.28 mJ, which is under safe conditions. However, at some moments, the effective ignition energy is larger than the safe value, making the gas in the minimum ignition energy range of explosion. This study may provide scientific basis for anti-static measures during coal mine gas extraction.

Circumfluent Drag Torque Model for Pin Pulverizer Based on Dimensional Analysis

ZHAO Dongmei, HUANG Peng, DIAO Xiong
Science & Technology Review. 2014, 32 (14): 64-68. ;  doi: 10.3981/j.issn.1000-7857.2014.14.010
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Abstract ( 178 )
This paper investigates the mathematical model of circumfluent drag torque of pin pulverizers using computational fluid dynamics (CFD) method, orthogonal test method, and dimensional analysis. The drag torque of pins at two circles was studied based on validation of the computational model. The key structural parameters and operating parameters of the pin pulverizer were considered in the orthogonal test. The orthogonal test data were non-dimensionalized, and the dimensionless parameters' polynomials were used to fit the data, by which the mathematical model of drag torque of the pin pulverizer was established. The computational results show that errors between the predicted value and CFD calculations of the drag torque of pins at two circles under two different conditions were 9.832%, 28.914% and 10.321%, 5.442%, showing this model could satisfy engineering precision.

Lane Changing Intent Identification Based on Logistic Regression Model

PENG Jinshuan, FU Rui, SHAO Yiming, XU Lei
Science & Technology Review. 2014, 32 (14): 69-73. ;  doi: 10.3981/j.issn.1000-7857.2014.14.011
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Abstract ( 287 )
To reduce the risk of lane changes, a method for lane changing intent identification is proposed based on the logistic model. By using faceLAB visual tracking system, experiments were conducted under real road environment for the purpose of studying drivers' lane changing intent identification. On the basis of the drivers' fixation characteristics of the rearview mirrors before lane changing operation, the size of the time window for lane changing behavior is determined. Based on difference analysis of visual characteristics between lane keeping and lane changing intent stages, saccade numbers, visual search width in the horizontal direction, saccade amplitude, and standard deviation of head rotation angles in the horizontal direction are selected as the characteristic indice to identify drivers' lane changing intent. The logistic model is constructed based on the leaning samples'characteristics. The model is applied to the lane changing intent identification process after the validity test. The results show that the identification rate reached 90.24%. Compared with the lane changing intent identification based on turn signals, the logistic model has significant advantages in terms of time series and identification rate.

A Rat Model of Hepatocarcinoma Carrying Abnormal Savda and Its Morphological Study

WANG Yanjiao, UPUR Halmurat, MAMATIMIN Imam, HELIM Resalat, ABDURIYIM Ayupjan, BAKRI Iskandar
Science & Technology Review. 2014, 32 (14): 74-78. ;  doi: 10.3981/j.issn.1000-7857.2014.14.012
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Abstract ( 246 )
The effect of abnormal savda on the initiation and development of hepatocarcinoma was studied by establishing a rat model of hepatocarcinoma carrying abnormal savda. A rat model with abnormal savda disease was first established, and diethylnirtosamine (DEN) was used to further establish a model of hepatocarcinoma carrying abnormal savda under Uighur medicine treatment. The morphology and pathological changes of the liver were observed at the 11th, 15th and 20th week. After the 20th week, cancerization was induced both in the experimental group (hepatocarcinoma with abnormal savda) and the model control group (without abnormal savda syndrome but DEN treatment), but the pathological changes of the liver surface in the experimental group appeared faster than those in the model control group, and the incidence of hepatocellular carcinoma (100%) of the former was significantly higher than that of the latter (72%) (P<0.01). These findings indicate that abnormal savda hilit facilitates transformation of hepatocyte to hepatocellular carcinoma.
Reviews

Birth Oxidative Stress and the Development of Antioxidant System in Newborns

LI Tiejun, YIN Jie, DUAN Jielin, WU Li, YIN Yulong
Science & Technology Review. 2014, 32 (14): 79-83. ;  doi: 10.3981/j.issn.1000-7857.2014.14.013
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Abstract ( 313 )
Oxidative stress is considered to be an imbalance between oxidation and anti-oxidation and the tendencytowards theoxidative state. Many studieshave demonstrated that environmental changes (i.e. oxygen concentration) and other stresses induce a significant increase in generation of reactive oxygen species (ROS) in infants during birth process and disturb the oxidative balance. The antioxidant system of newborns is weak and insufficient to scavenge the excessive ROS, leading to birth oxidative injury. This review focuses on birth oxidative stress and development of the antioxidant system in newborns to provide corresponding reference for further research in this field.

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