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Science China(Technological Sciences) 2008年第9期51卷 1530-1541页

作者： ZHAO ChengGang zhang xuedong School of Civil Engineering and Architecture Beijing Jiaotong UniversityBeijing 100044China

Based on the balance equations for mass, linear momentum, energy in porous media theory and some hypotheses in unsaturated soil mechanics, an expression of the total deformation work W is derived, and with the help of the specific ex-pression of the work, the effective stress conjugated with the displacement of the soil skeleton is suggested by the authors, which has the similar form as the expressions proposed by Wheeler (2003) and some other researchers according to their experience and intuition, but the effective stress presented in this paper is derived on the basis of porous media theory and its assumptions, whose premise and hypothesis are clear. It is also pointed out that due to the complexity of the physical mechanism and various influencing factors, it is impossible in unsatu-rated soil mechanics to determine the deformation of solid skeleton by the effective stress only, like in the saturated soil mechanics. Besides, by using the expression of the deformation work and the free energy Aα for each phase, the applicability of the Phase Separation Principle proposed by Passman (1984) in unsaturated soil is discussed, and it is considered that the principle should not strictly apply to un-saturated soil mechanics.

关键词： total deformation work effective stress unsaturated soil Phase Separation Principle porous media theory

Structure and electrochemical properties of low-cobalt La_(1-x)Li_xNi_(3.2)Co_(0.3)Al_(0.3) (0≤x≤0.2) hydrogen storage electrode alloys

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Rare Metals 2006年第Z1期25卷 1-6页

作者： WEI xuedong LIU Yongning zhang Peng State Key Laboratory for Mechanical Behavior of Materials School of Material Science and Engineering Xi''an Jiaotong University Xi''an 710049 China State Key Laboratory for Mechanical Behavior of Materials School of Material Science and Engineering Xi''an Jiaotong University Xi''an 710049 China State Key Laboratory for Mechanical Behavior of Materials School of Material Science and Engineering Xi''an Jiaotong University Xi''an 710049 China

The structure and electrochemical properties of a new low cobalt hydrogen storage electrode alloys La1-xLixNi3.2Co0.3Al0.3 (0≤x≤0.2) were investigated with a different additions of Li in replacement of La. With the increase of Li contents the maximum discharge capacity increases from 240 mAh·g-1(x=0) to 328.4 mAh·g-1(x=0.1) and the cycle stability is improved correspondingly. The capacity decay can remain 28.6% (x=0.2) after 230 charge/discharge cycles. The high rate discharge(HRD) ability of the alloys(x≤0.1) is improved and the best HRD is 34.1%(x=0.1) under the discharge current density 1200 mA·g-1. It is found that the prepared alloys are basically composed of LaNi5 as matrix phase and LaNi3 as second phase(x≤0.1). But the abundance of LaNi3 phase dramatically decreases with increasing x. When x=0.2, a new phase Al(NiCo)3 is formed.

关键词： hydrogen storage alloy microstructure high rate discharge ability cycling stability

In situ observation of the electrochemical behavior of Li–CO_(2)/O_(2)batteries in an environmental transmission electron microscope

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Carbon Energy 2024年第4期6卷 244-255页

作者： Peng Jia Yunna Guo Dongliang Chen Jingming Yao xuedong zhang Jianguo Lu Yuqing Qiao Liqiang zhang Hebei Key Laboratory of Applied Chemistry College of Environmental and Chemical EngineeringYanshan UniversityQinhuangdaoChina State Key Laboratory of Metastable Materials Science and Technology Clean Nano Energy CenterYanshan UniversityQinhuangdaoChina State Key Laboratory of Silicon and Advanced Semiconductor Materials School of Materials Science and EngineeringZhejiang UniversityHangzhouChina Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education School of Materials Science and EngineeringXiangtan UniversityXiangtanChina

Li–CO_(2)/O_(2)batteries,a promising energy storage technology,not only provide ultrahigh discharge capacity but also capture CO_(2)and turn it into renewable *** electrochemical reaction pathways'ambiguity,however,creates a hurdle for their practical *** study used copper selenide(CuSe)nanosheets as the air cathode medium in an environmental transmission electron microscope to in situ study Li–CO_(2)/O_(2)(mix CO_(2)as well as O_(2)at a volume ratio of 1:1)and Li–O_(2)batteries as well as Li–CO_(2)*** discharge reactions take place successively in the Li–CO_(2)/O_(2)–CuSe nanobattery:(I)4Li^(+)+O_(2)+4e^(−)→2Li_(2)O;(II)Li_(2)O+CO_(2)→Li_(2)CO_(3).The charge reaction proceeded via(III)2Li_(2)CO_(3)→4Li^(+)+2CO_(2)+O_(2)+4e^(−).However,Li–O_(2)and Li–CO_(2)nanobatteries showed poor cycling stability,suggesting the difficulty in the direct decomposition of the discharge *** fluctuations of the Li–CO_(2)/O_(2)battery's electrochemistry were also shown to depend heavily on O_(2).The CuSe‐based Li–CO_(2)/O_(2)battery showed exceptional electrochemical *** Li^–CO_(2)/O_(2)battery offered a discharge capacity apex of 15,492 mAh g^(−1) and stable cycling 60 times at 100 mA g^(−1).Our research offers crucial insight into the electrochemical behavior of Li–CO_(2)/O_(2),Li–O_(2),and Li–CO_(2)nanobatteries,which may help the creation of high‐performance Li–CO_(2)/O_(2)batteries for energy storage applications.

关键词： CuSe nanosheets electrochemical reaction in situ environmental transmission electron microscopy Li-CO_(2)battery Li-CO_(2)/O_(2)battery Li-O_(2)battery

Shallow water bathymetry based on a back propagation neural network and ensemble learning using multispectral satellite imagery

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Acta Oceanologica Sinica 2023年第5期42卷 154-165页

作者： Sensen Chu Liang Cheng Jian Cheng xuedong zhang Jie zhang Jiabing Chen Jinming Liu Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology Nanjing UniversityNanjing 210023China Collaborative Innovation Center of South China Sea Studies Nanjing UniversityNanjing 210093China School of Geography and Ocean Science Nanjing UniversityNanjing 210023China Jiangsu Center for Collaborative Innovation in Novel Software Technology and Industrialization Nanjing 210023China Zhejiang Institute of Hydraulics and Estuary Hangzhou 310020China Institute of Defense Engineering Academy of Military SciencesBeijing 100036China

The back propagation(BP)neural network method is widely used in bathymetry based on multispectral satellite ***,the classical BP neural network method faces a potential problem because it easily falls into a local minimum,leading to model training *** study confirmed that the local minimum problem of the BP neural network method exists in the bathymetry field and cannot be ***,to solve the local minimum problem of the BP neural network method,a bathymetry method based on a BP neural network and ensemble learning(BPEL)is ***,the remote sensing imagery and training sample were used as input datasets,and the BP method was used as the base learner to produce multiple water depth inversion ***,a new ensemble strategy,namely the minimum outlying degree method,was proposed and used to integrate the water depth inversion ***,an ensemble bathymetric map was *** Reef,northeastern Jiuzhang Atoll,and Pingtan coastal zone were selected as test cases to validate the proposed *** with the BP neural network method,the root-mean-square error and the average relative error of the BPEL method can reduce by 0.65–2.84 m and 16%–46%in the three test cases at *** results showed that the proposed BPEL method could solve the local minimum problem of the BP neural network method and obtain highly robust and accurate bathymetric maps.

关键词： bathymetry back propagation neural network ensemble learning local minimum problem multispectral satellite imagery

Overview of key operation factors and strategies for improving fermentative volatile fatty acid production and product regulation from sewage sludge

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Journal of Environmental Sciences 2020年第1期32卷 93-111页

作者： Wei Fang xuedong zhang Panyue zhang Jijun Wan Hongxiao Guo Dara S.M.Ghasimi Xavier Carol Morera Tao zhang State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China School of Environmental Science and Engineering Beijing Forestry UniversityBeijing 100083China Department of Water Management Section Sanitary EngineeringDelft University of TechnologyPO Box 50482600 GA Delftthe Netherlands Department of Civil Engineering University of Kurdistan HewlerErbilKurdistan RegionIraq Institut Quimic de Sarria Uniuersitat Ramon LlullVia Augusta 390E-08017 BarcelonaSpain Key Laboratory of Northwest Water Resource Environment and EcologyMOEXi'an University of Architecture and TechnologyXi'an 710055China

In recent years,volatile fatty acid(VFA)production through anaerobic fermentation of sewage sludge,instead of methane production,has been regarded as a high-value and promising roadmap for sludge stabilization and resource *** review first presents the effects of some essential factors that influence VFA production and *** the second part,we present an extensive analysis of conventional pretreatment and co-fermentation strategies ultimately addressed to improving VFA production and ***,the effectiveness of these approaches is summarized in terms of sludge degradation,hydrolysis rate,and VFA production and *** to published studies,it is concluded that some pretreatments such as alkaline and thermal pretreatment are the most effective ways to enhance VFA production from sewage *** possible reasons for the improvement of VFA production by different methods are also ***,this review also highlights several current technical challenges and opportunities in VFA production with spectrum control,and further related research is proposed.

关键词： Sewage sludge Anaerobic digestion VFA production Pretreatment Co-fermentation

In-situ imaging the electrochemical reactions of Li-CO_(2) nanobatteries at high temperatures in an aberration corrected environmental transmission electron microscope

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Nano Research 2022年第1期15卷 542-550页

作者： Peng Jia Meiqi Yu xuedong zhang Tingting Yang Dingding Zhu Tongde Shen Liqiang zhang Yongfu Tang Jianyu Huang Clean Nano Energy Center State Key Laboratory of Metastable Materials Science and TechnologyYanshan UniversityQinhuangdao 066004China Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education School of Materials Science and EngineeringXiangtan UniversityXiangtan 411105China Hebei Key Laboratory of Applied Chemistry College of Environmental and Chemical EngineeringYanshan UniversityQinhuangdao 066004China

Rechargeable lithium-carbon dioxide(Li-CO_(2))batteries have attracted much attention due to their high theoretical energy densities and capture of C0_(2).However,the electrochemical reaction mechanisms of rechargeable Lo-CO_(2) batteries,particularly the decomposition mechanisms of the discharge product Li_(2)CO_(3) are still unclear,impeding their practical *** electrochemistry of Li_(2)CO_(3) is critical for improving the performance of Li-C0_(2) ***,in-situ environmental transmission electron microscopy(ETEM)technique was used to study electrochemistry of Li_(2)CO_(3) in Li-C0_(2) batteries during discharge and charge *** discharge,Li_(2)CO_(3) was nucleated and accumulated on the surface of the cathode media such as carbon nanotubes(CNTs)and Ag nanowires(Ag NWs),but it was hard to decompose during charging at room *** promote the decomposition of Li2C03,the charge reactions were conducted at high temperatures,during which Li_(2)CO_(3) was decomposed to lithium with release of *** functional theory(DFT)calculations revealed that the synergistic effect of temperature and biasing facilitates the decomposition of Li_(2)CO_(3).This study not only provides a fundamental understanding to the high temperature Li-C0_(2) nanobatteries,but also offers a valid technique,i.e.,discharging/charging at high temperatures,to improve the cyclability of Li-CO_(2) batteries for energy storage applications.

关键词： in-situ environmental transmission electron microscopy high temperature Li-C0_(2)nanobatteries electrochemistry Li2CO3

In-situ imaging electrocatalysis in a solid-state Li-O_(2) battery with CuSe nanosheets as air cathode

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Chinese Chemical Letters 2024年第5期35卷 466-470页

作者： Peng Jia Yunna Guo Dongliang Chen xuedong zhang Jingming Yao Jianguo Lu Liqiang zhang Hebei Key Laboratory of Applied Chemistry College of Environmental and Chemical EngineeringYanshan UniversityQinhuangdao 066004China Clean Nano Energy Center State Key Laboratory of Metastable Materials Science and TechnologyYanshan UniversityQinhuangdao 066004China State Key Laboratory of Silicon and Advanced Semiconductor Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou 310058China Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education School of Materials Science and EngineeringXiangtan UniversityXiangtan 411105China

The development of highly efficient catalysts in the cathodes of rechargeable Li-O_(2) batteries is a considerable *** enhance the electrochemical performance of the Li-O_(2) battery,it is essential to choose a suitable catalyst *** selenide(CuSe)is considered as a more promising cathode catalyst material for Li-O_(2) battery due to its better conductivity and rich electrochemical active ***,its electrochemical reaction and fundamental catalytic mechanism remain unclear till ***,in-situ environmental transmission electron microscopy technique was used to study the catalysis mechanism of the CuSe nanosheets in Li-O_(2) batteries during discharge and charge *** is found that Li_(2)O was formed and decomposed around the ultrafine-grained Cu during the discharge and charge processes,respectively,demonstrating excellent *** indicate that the freshly formed ultrafine-grained Cu in the conversion reaction catalyzed the latter four-electron-transfer oxygen reduction reaction,leading to the formation of Li_(2)*** study provides important understanding of the electrochemistry of the LiO_(2) nanobatteries,which will aid the development of high-performance Li-O_(2) batteries for energy storage applications.

关键词： In-situ environmental transmission electron microscopy Lithium oxygen batteries CuSe nanosheets Oxygen reduction reaction Oxygen evolution reaction

Centrifuge modelling of tunnelling below existing twin tunnels with different types of support

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Underground Space 2022年第6期7卷 1125-1138页

作者： Qian Fang Xiang Liu Kehan Zeng xuedong zhang Mozhen Zhou Jianming Du Key Laboratory of Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijing 100044China College of Transportation Engineering Dalian Maritime UniversityDalian 116026China Western Investment Co. Ltd.of CCTEBChengdu 610041China China Institute of Water Resources and Hydropower Research Beijing 100038China

Tunnel excavation below existing tunnels produces ultimate and serviceability problems to the existing *** behaviours of induced stresses on the existing tunnels haven’t yet been fully *** this study,a centrifuge model test was adopted to investigate the effects of new tunnelling on two existing overlying *** existing tunnel model simulated a prototype composite lining tunnel and the other simulated a prototype segmental lining *** volume loss produced by new tunnel excavation was modelled by an in-flight actuator *** surface settlements,the existing tunnels settlements,the soil pressures on existing tunnels,the bending movements of existing tunnels,and the joint behaviours of existing tunnels were *** volume of surface settlement trough was much smaller than the soil volume moving into the tunnel,due to the heave of the tunnel bottom and the dilation of sand during *** maximum settlement of the segmental lining model was larger than that of the composite lining model as the equivalent bending stiffness of the composite lining model was larger than that of the *** to new tunnel excavation,the soil pressures on different positions of the existing tunnel behaved differently,and the bending movements of the existing tunnels ***,the joint deformation of existing tunnel caused by new tunnel excavation could be classified into three types:(1)translation,(2)rotation,and(3)combination of both.

关键词： Centrifuge model test Tunnelling below existing tunnel Settlement Joint deformation

Centrifuge Model Tests and Numerical Simulations of the Impact of Underwater Explosion on an Air-Backed Steel Plate

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Computer Modeling in Engineering & Sciences 2019年第1期118卷 139-155页

作者： Zhijie Huang Zuyu Chen Xiaodan Ren Jing Hu xuedong zhang Lu Hai MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Zhejiang UniversityHangzhou310058China Institute of Geotechnical Engineering Zhejiang UniversityHangzhou310058China China Institute of Water Resources and Hydropower Research Beijing100048China School of Civil Engineering Tongji UniversityShanghai200092China.

Damage and threats to hydraulic and submarine structures by underwater explosions(UNDEXs)have raised much *** centrifuge model test,compared to prototype test,is a more promising way to examine the problem while reducing cost and satisfying the similitude requirements of both Mach and Froude numbers *** study used a systematic approach employing centrifuge model tests and numerical simulations to investigate the effects of UNDEXs on an air-backed steel *** methodical centrifuge tests of UNDEXs were *** shock wave pressure,bubble oscillation pressure,acceleration and the strain of the air-backed steel plate were recorded and compared with numerical studies using the finite element analysis(FEA)commercial software *** implementing empirically derived and physically measured pressures into the numerical models,the effects of the shock wave and bubble oscillation on the steel plate were ***,the numerical results were in agreement with the experimental *** results showed that the peak pressure of an UNDEX has a significant effect on the peak acceleration of the steel plate and that the impulse of the UNDEX pressure governs the peak strain of the steel plate.

关键词： Centrifuge model tests numerical simulation underwater explosion shock wave bubble oscillation.

Boosting the energy density of sulfide-based all-solid-state batteries at low temperatures by charging to high voltages up to 6 V

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Nano Research 2023年第8期16卷 10966-10975页

作者： Lun zhang xuedong zhang Zhaoyu Rong Tao Wang Zhenyu Wang Zaifa Wang Longchen zhang Qiao Huang Lingyun Zhu Liqiang zhang Yongfu Tang Jianyu Huang Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education School of Materials Science and EngineeringXiangtan UniversityXiangtan 411105China Clean Nano Energy Center State Key Laboratory of Metastable Materials Science and TechnologyYanshan UniversityQinhuangdao 066004China Guilin Electrical Equipment Scientific Research Institute Co. LtdGuilin 541004China GRINM(Guangdong)Institute for Advanced Materials and Technology Foshan 528000China Hebei Key Laboratory of Applied Chemistry College of Environmental and Chemical EngineeringYanshan UniversityQinhuangdao 066004China School of Materials Science&Engineering Anhui UniversityHefei 230601China

Sulfide electrolyte-based all-solid-state batteries(ASSBs)are potential next generation energy storage technology due to the high ionic conductivity of sulfide electrolytes and potentially improved energy density and ***,the performance of ASSBs at/below subzero temperatures has not been explored ***,low temperature(LT)performance of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)|Li_(9.54)Si_(1.74)P_(1.44)S11.7Cl_(0.3)(LiSPSCl)|Li_(4)Ti_(5)O_(12)(LTO)ASSBs was *** charging the ASSB to 6 V at−40℃,a capacity of 100.7 mAh∙g^(−1)at 20 mA∙g^(−1)was achieved,which is much higher than that charged to 4.3 V(4.6 mAh∙g^(−1))at−40℃.Moreover,atomic resolution microscopy revealed that the NCM811 remained almost intact even after being charged to 6 *** contrast,NCM811 was entirely destructed when charged to 6 V at room *** sharp difference arises from the large internal charge transfer resistance at LT which requires high voltage to ***,such high voltage is not harmful to the active material but beneficial to extracting most energy out of the ASSBs at *** also demonstrated that thinner electrolyte is favorable for LT operation of ASSBs due to the reduced ion transfer *** work provides new strategies to boost the capacity and energy density of sulfide-based ASSBs at LT for dedicated LT applications.

关键词： all-solid-state lithium batteries sulfide solid electrolyte low temperature Li_(4)Ti_(5)O_(12)(LTO)