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1Molecular dynamics simulation of mechanical properties of TATB/fluorine-polymer PBXs along different surfaces显示文摘The mechanical properties of PBXs composed of the well-known insensitive explo-sive TATB (1,3,5-Triamino-2,4,6-trinitrobenzene) crystal and four kinds of typical fluo-rine-polymers, i.e. poly (vinylidene difluoride) (PVDF), polychlorotrifluoroethylene (PCTFE), fluo-rine rubber (F2311) and fluorine resin (F2314) individually, have been simulated by molecular dy-namics (MD) method. The results show that the mechanical properties of TATB can be effectively improved by blending with a small amount of fluorine-polymers. Different mechanical properties of PBXs are obtained by putting fluorine-polymer binders parallel to different crystalline surfaces. The whole effect of improving mechanical properties is found to be (010)?(100)>(001).XIAO Jijun1, HUANG Yucheng1, HU Yingjie1,2 & XIAO Heming1 1. Department of Chemistry, Nanjing University of Science and Technology, Nanjing 210094, China 2. Department of Chemistry, Nanjing Xiaozhuang College, Nanjing 210017, China Correspondence should be addressed to Xiao Heming (email: xiao@mail.njust.edu.cn) 2005Science China Chemistry2005,48,6:19
2Alekseevskii-Tate revisited:An extension to the modified hydrodynamic theory of long rod penetration显示文摘The modified hydrodynamic theory of long rod penetration into semi-infinite targets was established independently by Alek-seevskii and Tate over forty years ago and since then many investigators contributed much to the development of the high speed penetration mechanics.However,in all the models proposed so far,the target resistance Rt is not well defined and usually determined by adjusting it until the predicted depth of penetration comes to an agreement with experimental data.In this paper,assumptions are first made about particle velocity and pressure profiles together with response regions in the target and then an extension is made to the modified hydrodynamic theory of long rod penetration into semi-infinite targets,in which Rt has explicit form and is dependent on penetration velocity as well as thermo-mechanical properties of target material.The present model is compared with long rod penetration tests for different material combinations.It transpires that the present model predictions are in good agreement with the experimental data and numerical simulations in terms of penetration depth although many assumptions and simplifications are introduced into the paper.LAN Bin & WEN HeMing CAS Key Laboratory for Mechanical Behavior and Design of Materials,University of Science and Technology of China,Hefei 230027,China 2010Science China(Technological Sciences)2010,53,5:14
3Calculation of band structure in (101)-biaxially strained Si显示文摘The structure model used for calculation was defined according to Vegard's rule and Hooke's law. Calculations were performed on the electronic structures of(101)-biaxially strained Si on relaxed Si1-X GeX alloy with Ge fraction ranging from X = 0 to 0.4 in steps of 0.1 by CASTEP approach. It was found that [±100] and [00±1] valleys(-4) splitting from the [0±10] valley(-2) constitute the conduction b0and(CB) edge,that valence band(VB) edge degeneracy is partially lifted and that the electron mass is un-altered under strain while the hole mass decreases in the [100] and [010] directions. In addition,the fitted dependences of CB splitting energy,VB splitting energy and indirect bandgap on X are all linear.SONG JianJun ZHANG HeMing HU HuiYong FU Qiang 2009Science China(Physics,Mechanics & Astronomy)2009,52,4:12
4Molecular dynamics study on the relationships of modeling,structural and energy properties with sensitivity for RDX-based PBXs显示文摘In this paper,a primary model is established for MD(molecular dynamics) simulation for the PBXs(polymer-bonded explosives) with RDX(cyclotrimethylene trinitramine) as base explosive and PS as polymer binder.A series of results from the MD simulation are compared between two PBX models,which are represented by PBX1 and PBX2,respectively,including one PS molecular chain having 46 repeating units and two PS molecular chains with each having 23 repeating units.It has been found that their structural,interaction energy and mechanical properties are basically consistent between the two models.A systematic MD study for the PBX2 is performed under NPT conditions at five different temperatures,i.e.,195 K,245 K,295 K,345 K,and 395 K.We have found that with the temperature increase,the maximum bond length(L max) of RDX N N trigger bond increases,and the interaction energy(E N-N) between two N atoms of the N-N trigger bond and the cohesive energy density(CED) decrease.These phenomena agree with the experimental fact that the PBX becomes more sensitive as the temperature increases.Therefore,we propose to use the maximum bond length L max of the trigger bond of the easily decomposed and exploded component and the interaction energy E N-N of the two relevant atoms as theoretical criteria to judge or predict the relative degree of heat and impact sensitivity for the energetic composites such as PBXs and solid propellants.XIAO JiJun ZHAO Li ZHU Wei CHEN Jun JI GuangFu ZHAO Feng WU Qiang XIAO HeMing 2012Science China Chemistry2012,55,12:12
5Carbon neutrality needs a circular metal-energy nexus显示文摘Carbon neutrality requires systematic transformations of both energy and metal systems.These transformations are not isolated but rather interlinked and interdependent,such that trade-offs between different strategies exist.Herein,we explore the critical interlinkages between energy and metal systems and further propose a circular metal-energy nexus to advance global coordinated actions towards a carbon-neutral future.Peng Wang Heming Wang Wei-Qiang Chen Stefan Pauliuk 2022Fundamental Research2022,2,3:10
6Solution of an Inverse Problem of Heat Conduction of 45 Steel with Martensite Phase Transformation in High Pressure during Gas Quenching显示文摘In order to simulate thermal strains, thermal stresses, residual stresses and microstructure of the steel during gas quenching by means of the numerical method, it is necessary to obtain an accurate boundary condition of temperature field. The surface heat transfer coefficient is a key parameter. The explicit finite difference method, nonlinear estimation method and the experimental relation between temperature and time during gas quenching have been used to solve the inverse problem of heat conduction. The relationship between surface temperature and surface heat transfer coefficient of a cylinder has been given. The nonlinear surface heat transfer coefficients include the coupled effects between martensitic phase transformation and temperature.Heming CHENG, Tianchun HE and Jianbin XIEDepartment of Engineering Mechanics, Kunming University of Science and Technology, Kunming 650093, China 2002Journal of Materials Science & Technology2002,18,4:10
7Analytical model for cratering of semi-infinite metallic targets by long rod penetrators显示文摘Analytical model is presented herein to predict the diameter of crater in semi-infinite metallic targets struck by a long rod penetrator. Based on the observation that two mechanisms such as mushrooming and cavitation are involved in cavity expansion by a long rod penetrator, the model is constructed by using the laws of conservation of mass, momentum, energy, together with the u-v relationship of the newly suggested 1D theory of long rod penetration (see Lan and Wen, Sci China Tech Sci, 2010, 53(5): 1364–1373). It is demonstrated that the model predictions are in good agreement with available experimental data and numerical simulations obtained for the combinations of penetrator and target made of different materials.WEN HeMing, HE Yu & LAN Bin CAS Key Laboratory for Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei 230027, China 2010Science China(Technological Sciences)2010,53,12:9
8Valence band structure of strained Si/(111)Si_(1-x)Ge_x显示文摘The strained Si techique has been widely adopted in the high-speed and high-performance devices and circuits. Based on the valence band E-k relations of strained Si/(111)Si1-xGex, the valence band and hole effective mass along the [111] and [-110] directions were obtained in this work. In comparison with the relaxed Si, the valence band edge degeneracy was partially lifted, and the significant change was observed band structures along the [111] and [-110] directions, as well as in its corresponding hole effective masses with the increasing Ge fraction. The results obtained can provide valuable references to the investigation concerning the Si-based strained devices enhancement and the conduction channel design related to stress and orientation.SONG JianJun, ZHANG HeMing, HU HuiYong, DAI XianYing & XUAN RongXi Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi’an 710071, China 2010Science China(Physics,Mechanics & Astronomy)2010,53,3:9
9Experimental measurement of the electrical conductivity of single crystal olivine at high temperature and high pressure under different oxygen fugacities显示文摘At 1.0-4.0 GPa and 1123-1473 K and under oxygen fugacity-controlled conditions (Ni + NiO, Fe + Fe3O4, Fe + FeO and Mo+ M0O2 buffers), a YJ-3000t Model six-anvil solid high-pressure apparatus and a Sarltron-1260 Impedance/Gain-Phase analyzer were employed to conduct an in situ measurement of the electrical conductivity of single crystal olivine. Experimental results showed that: (1) within the range of experimentally selected frequencies (103-106 Hz), the electrical conductivity of the sample is of great dependence on the frequency; (2) with the rise of temperature ( T), the electrical conductivity (σ) will increase, and the Arrenhius linear relationship is established between lgσ and 1/T; (3) under the control of oxygen buffer Fe+ Fe3O4, with the rise of pressure, the electrical conductivity tends to decrease whereas the activation enthalpy and independent-of-temperature preexponential factor tend to increase, with the activation energy and activation volume of the sample estimated at (1. 25 ± 0.08) eV and (0.105 ±0.025) cm3/mol, respectively; (4) under given pressure and temperature conditions, the electrical conductivity tends to increase whereas the activation energy tends to decrease with increasing oxygen fugacity; and ( 5) the mechanism of electrical conduction of small polarons can provide insight into the behavior of electrical conduction of olivine under high pressure and high temperature.DAI Lidong LI Heping LIU Congqiang CUI Tongdi SHAN Shuangming YANG Changjun LIU Qingyou DENG Heming 2006Progress in Natural Science:Materials International2006,16,4:9
10下投式探空资料对数值预报初始场影响的个例分析显示文摘通过对2000年8月加勒比海地区飓风Debby活动期间,连续2个时次中使用下投式探空资料同化分析后,利用英国气象局全球数值预报系统的数值预报分析场和背景场的对比分析,阐明了由于下投式探空资料的引入,较好地描述了实际大气的情况,为数值预报提供了较为接近实际的初始场,从而提高了数值预报的精度。其中以湿度场和风场的贡献为最大。曲晓波 Julian Heming 2006气象与环境学报2006,22,2:8
11Speech endpoint detection in low-SNRs environment based on perception spectrogram structure boundary parameter显示文摘The Perception Spectrogram Structure Boundary(PSSB)parameter is proposed for speech endpoint detection as a preprocess of speech or speaker recognition.At first a hearing perception speech enhancement is carried out.Then the two-dimensional enhancement is performed upon the sound spectrogram according to the difference between the determinacy distribution characteristic of speech and the random distribution characteristic of noise.Finally a decision for endpoint was made by the PSSB parameter.Experimental results show that,in a low SNR environment from-10 dB to 10 dB,the algorithm proposed in this paper may achieve higher accuracy than the extant endpoint detection algorithms.The detection accuracy of 75.2%can be reached even in the extremely low SNR at-10 dB.Therefore it is suitable for speech endpoint detection in low-SNRs environment.WU Di ZHAO Heming HUANG Chengwei XIAO Zhongzhe ZHANG Xiaojun XU Yishen TAO Zhi 2014Chinese Journal of Acoustics2014,33,4:8
12Oral immune regulation using colitis extracted proteins for treatment of Crohn's disease: Results of a phase Ⅰ clinical trial显示文摘AIM: To evaluate safety and possible efficacy of induction of oral immune regulation using colitis extracted proteins(CEP) in Crohn's disease (CD) subjects.METHODS: Ten CDs were treated orally with autologous CEP thrice weekly for 16 wk. Subjects were monitored for CDAI and IBDQ. Immune modulatory effect was assessed by T-lymphocyte FACS analysis, CEP-specific IFNγ ELISPOT assay and cytokine levels.RESULTS: Induction of oral immune regulation significantly ameliorated disease activity. All (10/10) subjects had clinical response (CDAI≤70) and 7/10 achieved clinical remission (CDAI≤150). Significant increase in mean IBDQ score was noted (134±9vs 164±12). No treatment-related adverse events were noted. High levels of CEP-specific IFNγ spot forming colonies were detected in five subjects prior to treatment and in all five, a marked decrease was observed. The CD4+/CDS+ lymphocyte ratio and peripheral NKT cell numbers increased significantly, in 7/10 and in 5/10 subjects, respectively. Significant increase in serum IL-10 and IL-4 levels was observed in 7/10 subjects during treatment period.CONCLUSION: Immune regulation via oral administration of CEP is a safe and possibly effective treatment for subjects with moderate CD and may provide means of antigen-specific immune modulation.Eran Israeli Eran Goldin Oren Shibolet Athalia Klein Nilla Hemed Dean Engelhardt Elazar Rabbani Yaron Ilan 2005World Journal of Gastroenterology2005,11,20:8
13A New Species of the Genus Protobothrops(Squamata:Viperidae:Crotalinae) from the Dabie Mountains,Anhui,China显示文摘During a biological survey in July 2011, a pit viper was collected from the Yaoluoping Nature Reserve in the Dabie Mountains, Anhui, China. The pit viper's the total length measured 836 mm with a dorsal ground color of yellowbrown, decorated by 56 dark-brown transverse bands. The 4thsupralabial squama of the new species is separated from subocular by two squamae, and the tip of tail is orange; this combination of characters distinguish it from other species of the genus Protobothrops. Based on the body proportions, number of squamae, body color pattern, and comparing the data of its life history with those of other species of Protobothrops, we herein describe it as a new species, belonging to the genus of Protobothrops.Xin HUANG Tao PAN Demin HAN Liang ZHANG Yinxu HOU Lei YU Heming ZHENG Baowei ZHANG 2012Asian Herpetological Research2012,3,3:7
14Anomaly and geochemistry of rare earth elements and yttrium in the late Permian coal from the Moxinpo mine,Chongqing,southwestern China显示文摘The rare earth elements and yttrium(REY)of the K2 coal from the Moxinpo mine,Chongqing,were determined using inductively coupled plasma mass spectrometry(ICP-MS).The results show that REY are enriched in the K2 coal,with the average content up to 462 lg/g,much higher than average values of most coals in the world.The REY distribution patterns indicate that the light REY is enriched and show a well-pronounced Eu minimum.The fractionation of individual light-REY is higher than that of the heavy-REY.The REY distribution through the K2 coal seam shows that the top and bottom portion of the coal seam have a lower content of REY than the middle portion.Goyazite and rhabdophane were identified with a scanning electron microscope equipped with an energy-dispersed X-ray spectrometer(SEM-EDX).The REY distributions through the coal seam,SEM-EDX data and the correlation analysis between ash yields and the concentrations have revealed that the REY mainly occurs in the organic matter.The K2 coal is a potential rare-metal resource due to its high REY contents,and the coal ash could be regarded as a new and promising raw material for recovery of REY as a by-product.Jianhua Zou Dong Liu Heming Tian Tian Li Feng Liu Lin Tan 2014International Journal of Coal Science & Technology2014,1,1:7
15Combinative Algorithms for the Multidisciplinary Collaborative Simulation of Complex Mechatronic Products Based on Major Step and Convergent Integration Step显示文摘Multidisciplinary collaborative simulation (MCS) is an important area of research in the domain of multidisciplinary design optimization (MDO).Although previous research for MCS has to some extent addressed some issues like using of multiple tools,integration stability,control of step size,data synchronization,etc,further work is still necessary to study how to achieve improved precision.A theoretical model is formulated to describe and analyze the integration process of MCS.A basic algorithm with equal major steps is proposed based on the model,along with two methods of implementation for the model,namely the serial method and the parallel method.A further algorithm based on convergent integration step is proposed,which has a more flexible strategy for run-time integration.The influence of interpolation techniques on simulation performance is studied as well.Simulations of the performance of various algorithms with different interpolation techniques are performed for both a simple numerical example and a complex mechatronic product.The novel algorithm based on convergent integration step,when used with a high-order interpolation technique,has better performance in terms of precision and efficiency.The innovation of this paper is mainly on the validation of high precision of the proposed convergent integration step algorithm.LIANG Silue ZHANG Heming WANG Hongwei 2011Chinese Journal of Mechanical Engineering2011,24,3:6
16Predicting the penetration of long rods into semi-infinite metallic targets显示文摘Analytical equations are presented herein to predict the penetration of semi-infinite metallic targets struck normally by long rods at high velocities for YpHE Yu WEN HeMing 2013Science China(Technological Sciences)2013,56,11:6
17Fiber Bragg grating monitors for thermal and stress of the composite insulators in transmission lines显示文摘Running composite insulators are prone to failure due to their harsh surrounding work environment, which directly affects the safe operation of transmission lines. This paper puts forward the method of using fiber Bragg grating(FBG) as the monitors to parameters correlated with thermal and stress of the composite insulators in transmission lines at working status. Firstly, monitoring points are found out by the mechanical test on composite insulator samples. Secondly, based on the monitoring theory, this paper introduces the feasibility design frame of the composite insulator with FBG implanted in the rod and the online monitor system. At last, it describes applications of this monitor system in the field of transmission lines.Heming Deng Wei Cai You Song Jinsong Liu Christopher Redman Qiandong Zhuang 2018Global Energy Interconnection2018,1,3:6
18Longitudinal,transverse,density-of-states,and conductivity masses of electrons in(001),(101) and(111) biaxiallystrained-Si and strained-Si_(1-x)Ge_x显示文摘In this study,the electron effective masses,including longitudinal,transverse,density-of-states and conductivity effective masses,have been systematically investigated in(001),(101) and(111) biaxially strained Si and Si1-xGex.It is found that the effect of strain on the longitudinal and transverse masses can be neglected,that the density-of-states masses in(001) and(110) biaxially strained Si and Si1-xGex materials decrease significantly with increasing Ge fraction(x),and that the conductivity masses along typical orientations in(001) and(110) strained Si and Si1-xGex.are obviously different from those in relaxed Si.The quantitative results obtained from this work may provide valuable theoretical references to understanding strained materials physics and studying conduction channel design related to stress and orientations in the strained devices.SONG JianJun YANG Chao ZHANG HeMing HU HuiYong ZHOU ChunYu WANG Bin 2012Science China(Physics,Mechanics & Astronomy)2012,55,11:5
19PDMS microchannel fabrication technique based on microwire-molding显示文摘Micro-flow channel is basic functional component of microfluidic chip,and every step-forward of its construction technique has been receiving concern all over the world.This article presents a not-complicated but flexible method for fabrication of micro-flow channels.This method mainly utilizes the conventional molding capability of polydimethylsiloxane(PDMS) and widespread commercial microwires as templates.We have fabricated out some conventional types of microchannels with different topological shapes,as examples for the demonstration of this flexible fabrication route which was not dependent on the stringent demands of photolithographical or microelectromechanical system(MEMS) techniques.The smooth surface,high-intensity,and high flexibility of the wires made it possible to create many types of topological structures of the two-dimensional or three-dimensional microchannel or channel array.The geometric shape of the cross-section of thus forming microchannel in PDMS was the negative of that of embedded-in microwire,in high-fidelity if suitable measures were taken.More-over,such a microchannel fabrication process can easily integrate the conductivity and low resistivity of the metal wire to create micro-flow devices that are suitable for the electromagnetic control of liquid or the temperature regulation in the microchannel.Furthermore some preliminary optical analysis was provided for the observation of thus forming rounded microchannel.Based on this molding strategy,we even made some prototypes for functional microflow application,such as microsolenoids chip and temperature control gadgets.And an experiment of forming a droplet in the cross channel further confirmed the feasibility and applicability of this flexible microchannel forming technique.JIA YueFei JIANG JiaHuan MA XiaoDong LI Yuan HUANG HeMing CAI KunBao CAI ShaoXi WU YunPeng 2008Chinese Science Bulletin2008,53,24:5
20Preparation,crystal structure and quantum chemical investigation of[Li(NTO) (H_2O)_2]显示文摘[Li(NTO)(H2O2]was prepared by mixing the aqueous solution of 3-nitro-1,2,4-triazol-5-one (NTO) and lithium hydroxide. The crystal structure of [Li(NTO)(H2O)2] was determined by single crystal diffraction analysis. The crystal is monoclinic, space group P21/n with crystal parameters of α =0.7420(2) nm, b=0.344 9(1) nm, c=2.490 6(3) nm,β=94.89(1)°, Z=4, Dc=1.799 g.cm-3, V=0.635 nm3,μ= 1.591 cm-1, F(000) = 392. The final R is 0.051. The MNDO MO calculation shows that the coordinate bonds of title compound possess certain extent of covalent character. O2 atom of NTO anion is bonded to Li atom; the nitro group will be lost first when NTO is decomposed.SONG Jirong , CHEN Zhaoxu , XIAO Heming , HU Rongzu and LI Fuping Department of Chemical Engineering, Northwest University, Xi’ an 710069, China Department of Chemistry, Nanjing University of Science and Technology, Nanjing 210094, China Xi’an Modern Chemistry Research Institute, Xi’ an 710065, China 1999Chinese Science Bulletin1999,44,3:5
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