28 June 2015, Volume 33 Issue 12
    

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  • Preparation of diethylamine-d10
    LIU Zijie, YU Wenjun, XIE Xilei, LIU Gang
    Science & Technology Review. 2015, 33(12): 15-18. https://doi.org/10.3981/j.issn.1000-7857.2015.12.001
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    Diethylamine, one of the important organic chemicals, is widely used in preparation of pharmaceutical intermediates, and is often an important candidate of active fragments of drugs. It is reported that replacing H atom of N-alkyl with D atom would improve drug pharmacokinetic properties. This paper further develops the diethylamine-d10 synthetic process which uses ethanol-d6 as the starting material, with an overall yield of more than 40% for the three reaction steps and the deuterium abundance of diethylamine-d10 being more than 98%. These results are useful for development of novel deuterium drug candidates containing diethylamine-d10 fragments.
  • A scheme of lunar surface nuclear reactor power
    YAO Chengzhi, HU Gu, XIE Jiachun, ZHAO Shouzhi, GUO Jian
    Science & Technology Review. 2015, 33(12): 19-23. https://doi.org/10.3981/j.issn.1000-7857.2015.12.002
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    To establish a lunar base, the energy supply is a first issue to be solved. The nuclear reactor power has the advantages of high power, long service life and environmental resistance ability. It is an ideal energy solution option for the lunar base and other deep space exploration missions. A brief analysis of the current status of the energy resources that can be used for a lunar base is made. The design idea of a 40 kWe nuclear reactor power for the lunar surface is proposed. After the preliminary optimization design, the scheme and the overall design parameters of the nuclear reactor power are given. Finally, the power scheme is analyzed and demonstrated from the aspects of the reactor physics, the shielding, the thermal performance and structure. It is shown that the nuclear reactor power scheme is reasonable and feasible. It can meet the requirements of safety and long life service.
  • The detection of aircraft conflicts based on video image processing
    XIA Zhenghong, WU Yuezhou, LU Guopan
    Science & Technology Review. 2015, 33(12): 24-28. https://doi.org/10.3981/j.issn.1000-7857.2015.12.003
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    The ASR (aerodrome surveillance radar) can not be applied for a medium and small airport due to its high cost, and multi cameras might be used instead of the ASR to monitor the aircraft's movements there. By using the image edge detection and morphological image process approaches, the moving targets are recognized. And the tracks of aircraft are extracted, as well as their motion parameters. The moving target tracking algorithms and the conflict detecting model based on the DCPA (distance of closest point of approach) and the TCPA (time of closest point of approach) are proposed, and a prototype system is developed and applied in one General Aviation Airport for the conflict detecting, which shows that the aircraft conflict is effectively detected by this model and the video image process approach, and the safety and the efficiency of the airport ground operation are enhanced.
  • Penetration rate model of roller bit based on revolving indentation theory
    FENG Fuping, AI Chi, LÜ Yuanyuan, XING Jun, XU Haisu, GAO Jian, YAN Maosen
    Science & Technology Review. 2015, 33(12): 29-32. https://doi.org/10.3981/j.issn.1000-7857.2015.12.004
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    The roller bit acts on the bottom hole rock jointly by a vertical indentation and a level shave shear during the rotary drilling. For its analysis, this paper establishes a prediction model for the rate of penetration based on the revolving indentation theory of the roller bit, and through the laboratory tests, obtains the influence coefficient for rock breaking caused by the chisel teeth true rolling pluridentate linkage. The prediction error for the rate of penetration is 4.1% in average. The model provides a theoretical basis for the accurate prediction of the rate of penetration of the roller bit in the rotary drilling. It is concluded that, taking the level shave shear force into consideration, the intrusive depth of the roller bit is increased as compared with the case of only vertical pressing. The difference is smaller for the case of small frictional coefficient and cutting tip angle. However, it becomes greater with the increase of the frictional coefficient and cutting tip angle, so the effect of the horizontal scrapping cannot be ignored.
  • Calculation of fracturing pressure during waterflooding with considerations of water temperature and reservoir plugging
    SUN Jin, PENG Chengyong, YU Baohua, DENG Jingen
    Science & Technology Review. 2015, 33(12): 33-37. https://doi.org/10.3981/j.issn.1000-7857.2015.12.005
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    The fracturing pressure is affected by the reservoir temperature change and the formation plugging during the long-term water injection. However, the two influencing factors have not been considered in the existing fracturing pressure calculation model. So it is necessary to incorporate the two factors into the model. Based on the poroelasticity theory, the stresses induced by the in-situ stress and the fluid flow are calculated. And the temperature stresses are calculated based on the theory of elasticity. According to the superposition principal, the effective stresses on the borehole wall are obtained. With the considerations of the reservoir temperature and the plugging, a fracturing pressure analytical model during the waterflooding is established. This analytical model is verified by the conventional calculation model. The influences of the reservoir temperature and the plugging are analyzed. It is shown that the fracturing pressure decreases linearly with the decrease of the water temperature. And with the increase of the elastic modulus and the coefficient of linear expansion, the change extent of fracturing pressure is getting larger. Compared with the formation plugging zone, the filter cake thickness and the permeability have a greater impact. With the increase of the filter cake thickness and the decrease of its permeability, the fracturing pressure would increase. If the filter cake exists, the fracturing pressure decreases with the increase of the plugging zone radius. However, the permeability of the plugging zone has little impact on the fracturing pressure. And the plugging zone in the formation would not affect the fracturing pressure if the filter cake does not exist.
  • Method of numerical simulations for inclined shaft freezing sinking
    YANG Renshu, WANG Qianxing
    Science & Technology Review. 2015, 33(12): 38-43. https://doi.org/10.3981/j.issn.1000-7857.2015.12.006
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    In order to improve the simulation accuracy of the initial stress field and the digging process in inclined shaft sinking with ANSYS, a new method combining the double-model method and the advanced overlapping-element method is put forward. With a freezing inclined shaft construction in mind, taking the frozen soil as an elastic-plastic medium, a plane model of the freezing sinking of the inclined shaft is established, and the simulation is carried out. The simulation results show that the distribution characteristics of the model initial stress and displacement qualitatively agree with the theoretical results of the original ground stress obtained by adopting the double-model for the initial stress-displacement field. An advanced overlapping-element is adopted in simulating the excavation and support process under the total unloading, and the hoop stress of the inner shaft lining below 10-6 MPa, and the lining displacement of below 10-7 m under different model depths are obtained, which are close to the theoretical values. It is shown that the new method is superior to the traditional method, and is more accurate.
  • Mechanical properties of prestressed high-intensity concrete pile and pile caps combined
    LI Yanyan, LI Zegao, LI Heqing, ZHAO Xiong
    Science & Technology Review. 2015, 33(12): 44-49. https://doi.org/10.3981/j.issn.1000-7857.2015.12.007
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    5 specimens of prefabricated pile combined with pile caps are tested under low cycle reciprocating loading. The failure patterns, the bearing capacity and the ductility, the forces in anchoring reinforcing bars, as well as the influence of different forms of the precast pile and pile cap anchoring reinforcing bars on the mechanical properties of the specimen are studied. It is shown that by anchoring reinforced connecting plate welded specimens, the inclined anchoring reinforcing bars can play a role in delaying the growth of cracks, increasing the bearing capacity of the specimen. The specimens with the pile body and the anchoring reinforcing bars can significantly improve the integrity of the pile cap assembly of the specimen and increase the bearing capacity, the ductility, and the deformation ability, and the bearing capacity of the anchoring reinforcing bars of oblique angle is better than that of the rectangular specimens.
  • Permeability characteristics of structurally anisotropic coal
    YUE Gaowei, WANG Hui, ZHAO Yu, LIANG Weimin
    Science & Technology Review. 2015, 33(12): 50-55. https://doi.org/10.3981/j.issn.1000-7857.2015.12.008
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    The coal permeability is a key parameter for the gas seepage characteristics and the migration law, and the structural anisotropy of the coal seam makes the permeability obvious orientation dependent. In this paper the gas permeability of raw coal specimens is measured in directions of face cleats and butt cleats under different gas pressures by a coal and rock permeability testing system. According to the equivalent displacement principle, the calculation model for the permeability of anisotropic coal is established and the directional characteristics of gas seepage are numerically simulated. It is shown that the structural anisotropy of coal has a great influence on the gas permeability of coal, the permeability in the direction of face cleats is larger than that in the direction of butt cleats, and the difference of coal permeability in the two directions reaches one order of the magnitude, and the more degraded the coal is, the greater the difference is. With the increase of the coal rank, the permeability decreases both in the directions of raw coal face cleats and butt cleats. With the increase of the gas pressure, the permeability decreases exponentially and the directionality coefficient peak increases and the directionality of gas seepage in the coal seam enhances. And under the same gas pressure, the lower the coal rank is, the weaker the directionality of gas seepage will be. This study provides some insight for optimizing the design and the layout of the gas drainage borehole in the coal seam, improving the gas drainage effect and achieving optimal extraction.
  • Self-flowing transportation of the large capacity super fine tailing slurry in overlength pipelines
    TIAN Minghua, WANG Xinmin, ZHANG Guoqing, ZHANG Qinli, LI Shuai
    Science & Technology Review. 2015, 33(12): 56-60. https://doi.org/10.3981/j.issn.1000-7857.2015.12.009
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    To solve the problem of poor self-flowing performance of the large capacity super fine tailing slurry in overlength pipeline transportation, this paper studies the self-flowing transportation, the hindered settling and the frictional resistance loss properties of the super fine tailing slurry. A pipeline model is built and the evaluation is made through the simulation software Fluent. It is revealed that the super fine tailings are easy to suspend and the large-tube pipeline transportation is beneficial to reducing the frictional resistance loss. With the working flow rate of 2.95 m·s-1, the pipeline's inner diameter of 155 mm, the vertical component of the fluctuating velocity reaches 0.24 m·s-1, which is far greater than the hindered settling rate of 0.034 m·s-1, and the maximum stowing gradient is up to 10.6.
  • Influence of molding process on the properties of packaging materials made from waste corrugated containers
    LI Chen, RONG Renhui, XIAO Shengling
    Science & Technology Review. 2015, 33(12): 61-66. https://doi.org/10.3981/j.issn.1000-7857.2015.12.010
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    Experiments are conducted to study the effects of the forming process on the properties of high strength packaging materials made from waste corrugated containers. The results are as follows. With the same degree of beating, increase of the hotpressing pressure can improve the tensile strength, elongation at break, and modulus of elasticity; Increase of the hot- pressing temperature can only improve the tensile strength and modulus of elasticity. When the hot-pressing temperature is 165℃, beating degree is 35°SR and hot pressing pressure is 2 MPa, the elongation at break is the largest. And the peak of burst degree appears at the condition of 150℃, 27°SR, and 5 MPa. The higher the hot press temperature, the smaller the pressure and, the better the stiffness. The results also show that in order to save energy and shorten the preparation cycle, a better molding process scheme uses 27°SR beating degree and 165℃ hot-pressing temperature, while 5 MPa hot pressing drying or 0.08 MPa vacuum drying condition can be selected according to the specific demand.
  • Influence of insulation technology by plastic greenhouse on working temperature in aeration tank in cold area in winter
    ZHAO Songying, ZHAN Naiyan
    Science & Technology Review. 2015, 33(12): 67-71. https://doi.org/10.3981/j.issn.1000-7857.2015.12.011
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    For the problem of low temperature in cold regions and low working temperature in aeration tanks in sewage works, the heat preservation technology in greenhouses of wastewater works is studied by means of simulation to analyze the temperature distribution and air flowing features in greenhouses. Results show that under the condition of -22℃ outdoors in winter, through the insulation of the canopy towards the aeration tank, the average air temperature remains at 4℃ or so, while the water temperature of the outlet of the aeration tank remains at about 11.2℃; The optimal material of insulation membrane of the outside aeration tank is PO, while the most undesirable material is PVC, And PE and EVA are mediate; and the aeration tank of the best heat preservation is the one that uses greenhouse of 2.5 meter height. The effect of double insulation membranes is better than that of a single membrane.
  • Clinical observation of BSD2000 deep hyperthermia combined with chemotherapy in patients with advanced pancreatic cancer
    DING Li, HU Xueqing, ZHAO Yunbo, AI Bin
    Science & Technology Review. 2015, 33(12): 72-76. https://doi.org/10.3981/j.issn.1000-7857.2015.12.012
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    This study aims to evaluate the short-term efficacy, pain reduction, quality of life (QQL) and toxicity of BSD2000 deep hyperthermia combined with chemotherapy in patients with advanced pancreatic cancer. All cases were diagnosed and treated in Beijing Hospital from October 2009 to October 2014. A total sixty patients with advanced pancreatic cancer were divided into two groups. Thirty patients in the combination therapy group received chemotherapy combined with BSD2000 deep hyperthermia(twice per week). Another thirty patients in the chemotherapy therapy group were only given chemotherapy. Twenty-one days were one cycle. The short-term efficacy, pain relief, QQL and toxicity were evaluated after two cycles. All sixty patients were assessable for response. The response rates for the combination therapy group and the chemotherapy therapy group were 10% and 6.7%, respectively, while the disease control rates for the two groups were 83% and 76%, respectively. There was no significant different between the two groups (P>0.05). The combination group showed significant improvement in pain relief and QQL compared to the control group (P<0.05). There were some mild side effects, such as gas trointestinal toxicities and myelosuppression, but no significant difference between the two groups (P>0.05). There was no severe side effect in the two groups. Even though there was no difference in efficacy, the combination group did show pain reduction, improved QQL and tolerable toxicity. BSD2000 deep hyperthermia combined with chemotherapy in patients with advanced pancreatic cancer is worthily recommended in the clinical application.
  • Intervention of Edaravone on expression of β amyloid and amyloid precursor protein after cerebral ischemia reperfusion
    REN Haiyan, ZHAO Hui, WANG Lei, XU Chenbo, MA Meilei, WEN Juan
    Science & Technology Review. 2015, 33(12): 77-82. https://doi.org/10.3981/j.issn.1000-7857.2015.12.013
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    This paper investigates the damage mechanism of rat hippocampal neurons induced by the ischemia reperfusion and the intervention of the Edaravone. An ischemia reperfusion model is built by the middle cerebral artery occlusion (MACO)-reperfusion method. The reperfusion is performed 2 hours after the ischemia and persists for 22 hours (24 h since surgery). According to the Zea Longa's 5 level evaluation method, the neurobehavioral score of rats is graded; The rats' tissue pathological morphological changes are observed by the HE staining; the expressions of amyloid β (Aβ) and its precursor (APP) in the hippocampus of rats are detected with the immunohistochemistry, the image analysis and the Western Blot. It is shown that the model group rats show obvious symptoms of the nerve function defect; By contrast, the Edaravone of 6 and 10 mg/kg could improve model rats' symptoms of the nerve defect in varying degrees; And the difference is more significant in 10 mg/kg group (P<0.01). The HE staining shows that the depigmentation of the model group rat hippocampal neurons is obvious, and the two treatment groups could reduce this kind of morphology change; The immunohistochemistry and Western Blot analysis results suggest that both levels of Aβ and APP in the model group are significantly higher than those in the sham group (P<0.01), however, in different concentrations of Edaravone groups, their expression is significantly reduced (P<0.05). It is concluded that the ischemia reperfusion could cause neuron cells' damage by increasing Aβ and APP, and the Edaravone might suppress their toxic effects and protect the neuron cells by decreasing their expression.
  • Newton iterative source localization search algorithm based on the time delay difference characteristic parameters discrimination
    FENG Lijie, FAN Yao
    Science & Technology Review. 2015, 33(12): 83-87. https://doi.org/10.3981/j.issn.1000-7857.2015.12.014
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    The positioning accuracy of the TDOA location system is mainly influenced by the time difference measurement and the sensor geometry distribution. For the real-time positioning, due to the mobility and the complexity caused by the environmental goal control, the reasonable, efficient and accurate determination of the measured time delay difference is a plagued issue for researchers. To solve this problem, this paper proposes a method to estimate the error signal delay discrimination based on characteristic parameters. The Newton iterative search algorithm is improved to search for the initial positioning and the end condition. Firstly, the signal characteristic value information is used to establish credibility, then the initial position of the source is found through three sensors of high reliability, its results are taken as the initial values of Newton iteration to avoid the complicated calculation of the traditional method. Finally, with the reliability of each sensor as the weight of the Newton iteration termination condition, the end condition is more reasonable, more close to reality. The experiment shows that this algorithm has high precision and strong robustness.
  • Evaluation of CN authority DNS mirror server distribution based on active measurement
    CHEN Wenyu, XIAO Zhongnan, XU Yanzhi
    Science & Technology Review. 2015, 33(12): 88-92. https://doi.org/10.3981/j.issn.1000-7857.2015.12.015
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    DNS(domain name server)is one of the most important basic facilities of Internet. The technique of DNS mirror is a key solution to improvinge DNS system's security, stability and analyticity. In this article, we develop a new solution to evaluation and optimization of the global CN DNS mirror distribution. We send a certain data package to the target server and calculate the response time for analysis of the scanned server's behavior. User's experiences that CN DNS servers' performances vary due to geographic differences are considered in our study. The solution can provide reliable suggestion to DNS distribution for a more efficient and orderly plan.
    • Reviews
  • Investigation of mercury- selenium interaction in bio- organisms using metallomics approach
    ZHAO Jiating, LI Yufeng, ZHU Nali, GAO Yuxi, CHAI Zhifang
    Science & Technology Review. 2015, 33(12): 93-100. https://doi.org/10.3981/j.issn.1000-7857.2015.12.016
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    As metallomics becomes a focus area in recent years, the related research approaches are getting a rapid development. Especially for the nuclear analysis techniques, such as isotope dilution (tracer) technique, synchrotron radiation X ray fluorescence analysis (SR-XRF), and synchrotron radiation X ray absorption spectroscopy (SR-XAS) techniques, combined with other biochemical separation and analysis techniques like electrophoresis, high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS), electrospray ionization mass spectrometry (ESI-MS) and so on, they have been widely used for the function and interaction research of Hg and Se in bio-organisms. Selenium (Se) is one of the essential trace elements for human and animals, and can apparently antagonize the toxicity of heavy metals such as mercury (Hg). To analyze the distribution and speciation of Se and Hg in organisms, to get a insight into their absorption, transformation and accumulation in different tissues, and to further explore the potential roles of Se on the bio- effects of Hg in organisms is quite crucial for the control of Hg pollution and the acquaintance with Hg-Se interaction in bio-organisms. Based on the previous reports and the results from our lab, the present work will give an informative review about the metallomics approaches as applied in the research of Hg, Se interaction in bio-organisms.
  • Novel air cleaners and their evaluation methods
    LU Li, HE Junhui, TIAN Hua, HE Pu, YANG Qiaowen
    Science & Technology Review. 2015, 33(12): 101-109. https://doi.org/10.3981/j.issn.1000-7857.2015.12.017
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    More and more frequent haze days increase the concern over indoor air quality. Traditional indoor air cleaners no longer satisfy the requirements of indoor air purification. Thus, development of novel multifunctional air cleaners and comprehensive air purification technologies become a major research direction toward improving indoor air quality and meeting new needs of current market. By summarizing recent researches on indoor air cleaners of both at home and abroad, herein we review several novel indoor air cleaners, including new adsorption materials, non- thermal plasma, photocatalytic, catalytic oxidation and multifunctional air cleaners, and analyze their advantages and disadvantages. The main evaluation indexes and methods of novel air cleaners are also summarized, including the evaluation methods for gas pollutants, solid particles and microbial contaminants. An outlook is also made toward the future research directions of indoor air cleaners.
  • Progress in studies of brazed diamond tools
    ZHANG Wenjiao, KONG Xiangqing, QU Yandong
    Science & Technology Review. 2015, 33(12): 110-115. https://doi.org/10.3981/j.issn.1000-7857.2015.12.018
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    The studies of brazed diamond tools are reviewed in this paper focusing on the brazing materials and the brazing processes, and how to use the brazing technology to improve the performance of the diamond tools is discussed. Problems in the current studies of brazed diamond tools are analyzed. Some suggestions for the future research directions, especially for the nickel based brazed impregnated diamond tools, are given.
    • Focus
  • Construction of a micro positioning navigation and timing system: A change of the pattern of PNT service
    YOU Zheng, MA Lin
    Science & Technology Review. 2015, 33(12): 116-119. https://doi.org/10.3981/j.issn.1000-7857.2015.12.019
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    The positioning navigation and timing (PNT) is a dual-use technology which concerns the national strategy. The traditional global navigation satellite system is susceptible to the interference and the shelter and the inertial navigation error is accumulated. Based on the MEMS technology, combining the chip-scale atomic clock and the MEMS inertial measurement unit with the receiver of the global navigation satellite system, a micro positioning navigation and timing unit is formed. The atomic clock of the unit provides the precision clock signal, the unit broadcasts the positioning navigation and timing signal and the PNT nets are constructed. The units can be carried by micro-satellites or UAVs. The number of the units for the micro positioning navigation and timing system can be freely chosen and the arrangement can be freely configured. The micro positioning navigation and timing system can overcome the problems of the traditional PNT methods and change the pattern of the PNT.

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