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The Removal and Remediation of Phenanthrene and Pyrene in Soil by Mixed Cropping of Alfalfa and Rape

Agricultural Sciences in China 2008年第11期7卷 1355-1364页

作者： PAN sheng-wang WEI Shi-qiang YUAN Xin CAO sheng-xian Key Laboratory of Agricultural Resources and Environment in Chongqing College of Resources and Environment Southwest University Chongqing 400716 P.R.China

The mechanisms and efficiencies of the removal and remediation of polycyclic aromatic hydrocarbons （PAHs） in soils by different planting patterns with rape （Brassica campestris） and alfalfa （Medicago sativa） were studied by pot experiments in a greenhouse. Results showed that the remediation efficiencies under mixed cropping of alfalfa and rape significantly exceeded those under single cropping when the initial concentrations of phenanthrene and pyrene were at 20.05-322.06 mg kg^-1 and 20.24-321.42 mg kg^-1, respectively. After 70 days plantation of crops, the contents of extractable PAHs in soils under mixed cropping were much lower than those under single cropping. About 65.17-83.52% of phenanthrene and 60.09%- 75.34% ofpyrene was removed from the soils under mixed cropping, respectively, which were averagely 43.26 and 40.38% for phenanthrene, and 11.03 and 16.29% for pyren higher than those under single cropping. Alfalfa or rape did absorb and accumulate PAHs from the soils apparently; the PAHs concentrations in plants monotonically increased with the increase of initial PAHs concentrations in soil; the accumulations of PAHs in plants showed following sequence as roots 〉 above parts, phenanthrene 〉 pyrene and single cropping 〉 mixed cropping at same contamination level. Despite the presence of vegetation significantly enhanced the remediation of PAHs in soils, contributions of abiotic loss, plant uptake, accumulation and microbial degradation was much lower than those of plant-microbial interactions in the process of phytoremediation. Thus plant-microbial interactions are the main mechanisms for the remediation enhancement of soil PAHs pollution under mixed cropping models. Results suggested a feasibility of the establishment of multi-species phytoremediation for the improvement of remediation efficiencies of PAHs, which may decrease accumulations of PAHs in crops and thus reduce their risks.

关键词： phytoremediation polycyclic aromatic hydrocarbons mixed cropping models plant-microbial interactions soil

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Access point selection in heterogeneous wireless networks using belief propagation

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Science China(Information Sciences) 2014年第6期57卷 103-112页

作者： HOU RongHui LI JianDong sheng Min YANG ChunGang State Key Lab of Integrated Service Networks Xidian University

The next generation wireless network will be composed by various heterogenous wireless access networks,such as cellular network,worldwide interoperability for microwave access(WiMAX),wireless local area network(WLAN),*** access networks cooperatively provide high-bandwidth connectivity with bandwidth *** paper proposes a utility-based access point selection scheme,which selects an accessible point for each user,such that the bandwidth requirement of each user is satisfied,and also the defined utility function is *** to the NP-complete nature of the problem,the existing proposals apply the greedy method to find a *** find that belief propagation is an efficient tool to solve this problem,and thus,we derive the same optimization objective in a new way,and then draw a factor graph representation which describes our combinatorial optimization ***,we develop the belief propagation algorithm,and show that our algorithm ***,we conduct numerical experiments to evaluate the convergency and accuracy of the belief propagation in load balancing problem.

关键词： heterogeneous wireless network QoS admission control belief propagation distributed algorithm

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Analysis of Frequency Characteristics and Sensitivity of Compliant Mechanisms

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Chinese Journal of Mechanical Engineering 2016年第4期29卷 680-693页

作者： LIU Shanzeng dai Jiansheng LI Aimin SUN Zhaopeng FENG Shizhe CAO Guohua School of Mechatronic Engineering China University of Mining and Technology King' s College University of London Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin University

Based on a modified pseudo-rigid-body model,the frequency characteristics and sensitivity of the large-deformation compliant mechanism are ***,the pseudo-rigid-body model under the static and kinetic conditions is modified to enable the modified pseudo-rigid-body model to be more suitable for the dynamic analysis of the compliant ***,based on the modified pseudo-rigid-body model,the dynamic equations of the ordinary compliant four-bar mechanism are established using the analytical ***,in combination with the finite element analysis software ANSYS,the frequency characteristics and sensitivity of the compliant mechanism are analyzed by taking the compliant parallel-guiding mechanism and the compliant bistable mechanism as *** the simulation results,the dynamic characteristics of compliant mechanism are relatively sensitive to the structure size,section parameter,and characteristic parameter of material on *** results could provide great theoretical significance and application values for the structural optimization of compliant mechanisms,the improvement of their dynamic properties and the expansion of their application range.

关键词： compliant mechanism pseudo-rigid-body model frequency characteristic sensitivity analysis finite element analysis

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Identification of candidate millisecond pulsars from Fermi LAT observations

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Research in Astronomy and Astrophysics 2016年第6期16卷 113-122页

作者： Xue-Jie dai Zhong-Xiang Wang Jithesh Vadakkumthani Yi Xing Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China University of Chinese Academy of Sciences Beijing 100049China

We report our detailed data analysis of 39 γ-ray sources selected from the 992 unassociated sources in the third Fermi Large Area Telescope Third Source Catalog. The selection criteria, which were set for finding candidate millisecond pulsars （MSPs）, are non-variables with curved spectra and 〉5° Galactic latitudes. From our analysis, 24 sources were found to be point-like sources not contaminated by back- ground or nearby unknown sources. Three of them, Jl544.6-1125, J1625.1-0021 and J1653.6-0158, have been previously studied, indicating that they are likely MSPs. The spectra of J0318.1＋0252 and J2053.9＋2922 do not have properties similar to known γ-ray MSPs, and we thus suggest that they are not MSPs. Analysis of archival X-ray data for most of the 24 sources was also conducted. Four sources were found with X-ray objects in their error circles, and 16 with no detection. The ratios between the γ-ray fluxes and X-ray fluxes or flux upper limits are generally lower than those of known γ-ray MSPs, suggesting that if the γ-ray sources are MSPs, none of the X-ray objects are their counterparts. Deep X-ray or radio observations of these sources are needed in order to identify their MSP nature.

关键词： stars pulsars -- stars binaries -- gamma rays stars

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Failure Mechanism and Stability Analysis of an Active Landslide in the Xiangjiaba Reservoir Area,Southwest China

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Journal of Earth Science 2018年第3期29卷 646-661页

作者： Javed Iqbal Fuchu dai Min Hong Xinbin Tu Qizhi Xie Institute of Geology and Geophysics Chinese Academy of SciencesBeijing 100029China Department of Earth Sciences Abbottabad University of Sciences and TechnologyAbbottabad 22500Pakistan Institute of Rock and Soil Mechanics Chinese Academy of SciencesWuhan 430071China Hydrochina Zhongnan Engineering Corporation Changsha 410014China

Dam construction for hydropower development is a very important subject all around the world, especially in developing countries due to energy crises. Filling of reservoir lakes may trigger or reactivate landslides in reservoir area. Active landslides in populated districts in the Xiangjiaba Reservoir area have become a striking problem for residents, local government and construction engineers. The key objective of this study is to analyze the role of reservoir filling and fluctuation in the activation/reactivation of the landslide as well as the mechanism of landslide from microstructures of pre-sheared slip surface. A large active landslide with a total volume of 1.25 Mm^3 at the left margin of Jinsha River in Pingshan County of Sichuan Province, Southwest China, was selected as a case study. Field investigation, field monitoring and laboratory tests were carried out to find out the failure mechanism and the stability of the active landslide. The shear strength test and stability analysis confirm that the water level fluctuations have an adverse effect on slope stability. It is obvious from microstructure analysis that the clay minerals contribute to down-slope movement at micro-scale as well as presence of expansive minerals （e.g., montmorillonite） decreases the strength of soil due to water level rise.

关键词： active landslide slope stability stability analysis microstructure montmorillonite.

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Michael addition reactions of cyclanones with acrylamides:Producing 2-carbamoylethyl derivatives or ene-lactams

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Science China Chemistry 2008年第11期51卷 1044-1050页

作者： dai WeiFeng WANG ChaoHua ZHANG Xi ZHANG JinMing LANG MeiDong Key Laboratory for Ultrafine Materials of Ministry of Education School of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China

The electron-withdrawing groups (EWGs) in the electrophilic alkenes employed in the Michael addition reaction are almost only CO2R, CN, COR, NO2, and SO2Ph. Although amides (CONR1R2) are also typical electron-withdrawing groups and are of great importance in organic synthesis, they are scarcely em-ployed as the EWGs of the electrophilic alkenes in the Michael addition reaction. In this work, the Mi-chael reactions of acrylamide and its derivatives with cyclanones were successfully carried out in the presence of enough radical inhibitors. The amide groups play a key role in producing the preferred products. The N-substituted acrylamides, including N-monosubstituted and N,N-disubstituted acryla-mides could react with cyclohexanone (CHn) to give the expected 2-carbamoylethyl derivatives; how-ever, acrylamide reacting with cyclohexanone only produced ene-lactam. Cyclanones also have effects on the products, while the ring size of cyclanones influences the reaction yield and the α-substituent decides the ratio of resulting isomeric ene-lactams.

关键词： Michael addition reaction cyclanone acrylamide ene-lactam 2-carbamoylethyl derivative

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Synchronous measurement of tribocharge and force at the footpads of freely moving animals

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Friction 2018年第1期6卷 75-83页

作者： Yi SONG Zhouyi WANG Jun ZHOU Yang LI Zhendong dai Institute of Bio-inspired Structure and Surface Engineering Nanjing University of Aeronautics and Astronautics College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics College of Astronautics Nanjing University of Aeronautics and Astronautics

Hypothesis on electrostatic attraction mechanisms involving the hairy adhesion of climbing animals has been a matter of controversy for several years. The detection of tribocharge and forces at attachment organs of animals is a practical method of clarifying the dispute with respect to electrostatic attraction in the attachment of animals. Nonetheless, the tribo-electrification is rarely examined in the contact-adhesion of animals(especially in their free and autonomous attachment) due to the lack of available devices. Therefore, the present study involves establishing a method and an apparatus that enables synchronous detection of tribocharge and contact forces to study tribo-electrification in the free locomotion of geckos. A type of a combined sensor unit that consists of a three-dimensional force transducer and a capacitor-based charge probe is used to measure contact forces and tribocharge with a magnitude corresponding to several nano-Coulombs at a footpad of geckos when they climb vertically upward on an acrylic oligomer substrate. The experimental results indicate that tribocharge at the footpads of geckos is related to contact forces and contact areas. The measured charge allows the expectation of an exact attraction with magnitude corresponding to dozens of newtons per square meter and provides a probability of examining tribo-electrification in animal attachment from a macro level.

关键词： tribocharge forces synchronous measurement animal free locomotion

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Effect of thermal shield and gas flow on thermal elastic stresses in 300mm silicon crystal

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Rare Metals 2006年第z2期25卷 45-50页

作者： GAO Yu XIAO Qinghua ZHOU Qigang dai Xiaolin TU Hailing General Research Institute for Nonferrous Metals Beijing 100088 China General Research Institute for Nonferrous Metals Beijing 100088 China General Research Institute for Nonferrous Metals Beijing 100088 China General Research Institute for Nonferrous Metals Beijing 100088 China General Research Institute for Nonferrous Metals Beijing 100088 China

The thermal elastic stresses induced in 300 mm Si crystal may be great troubles because it can incur the generation of dislocations and undesirable excessive residual stresses. A special thermal modeling tool, CrysVUn, was used for numerical analysis of thermal elastic stresses and stress distribution of 300 mm Si crystal under the consideration of different thermal shields and gas flow conditions. The adopted governing partial equations for stress calculation are Cauchy′s first and second laws of motion. It is demonstrated that the presence and shape of thermal shield, the gas pressure and velocity can strongly affect von Mises stress distribution in Si crystal. With steep-wall shield, however, the maximal stress and ratio of high stress area are relatively low. With slope-wall shield or without shield, both maximal stress and ratio of high stress area are increased in evidence. Whether thermal shields are used or not, the increase of gas flow velocity could raise the stress level. In contrast, the increase of gas pressure cannot result in so significant effect. The influence of thermal shield and gas flow should be attributed to the modification of heat conduction and heat radiation by them.

关键词： thermal elastic stress simulation 300 mm Si single crystal

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Azo dye degradation behavior of AlFeMnTiM(M = Cr, Co, Ni) high-entropy alloys

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International Journal of Minerals,Metallurgy and Materials 2019年第1期26卷 124-132页

作者： Shi-kai Wu Ye Pan Ning Wang Tao Lu Wei-ji dai School of Materials Science and Engineering Southeast University Jiangsu Key Laboratory for Advanced Metallic Materials

Because of the potential carcinogenic effects and difficult degradation of azo dyes, their degradation has been a longstanding problem. The degradation of azo dye Direct Blue 6(DB6) using ball-milled(BM) high-entropy alloy(HEA) powders was characterized in this work. Newly designed AlFeMnTiM(M = Cr, Co, Ni) HEAs synthesized by mechanical alloying(MA) showed excellent performance in the degradation of azo dye DB6. The degradation efficiency of AlFeMnTiCr is approximately 19 times greater than that of the widely used commercial Fe–Si–B amorphous alloy ribbons and more than 100 times greater than that of the widely used commercial zero-valent iron(ZVI) powders. The galvanic-cell effect and the unique crystal structure are responsible for the good degradation performance of the BM HEAs. This study indicates that BM HEAs are attractive, valuable, and promising environmental catalysts for wastewater contaminated by azo dyes.

关键词： high entropy alloy mechanical alloying AlFeMnTiM degradation performance azo dye

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Expert System for Accelerator Single-Freedom Nonlinear Components

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Chinese journal of nuclear physics 1995年第1期17卷 89-94页

作者： Wang, sheng Xie, Xi Liu, Chunliang Graduate School of Nuclear Industry Beijing China

An expert system by Arity Prolog is developed for accelerator single-freedomnonlinear *** automatically yields any order approximate analytical solu-tions for various accelerator single-freedom nonlinear *** an example,theeighth order approximate analytical solution is derived by this expert system for a gen-eral accelerator single-freedom nonlinear component,showing that the design of the ex-pert system is successful.

关键词： Accelerator single-freedom nonlinear component Expert system Any order approximate analytical solution

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