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Estimation of earth pressure against retaining walls with different limited displacement modes based on elastic theory

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Journal of Mountain Science 2022年第1期19卷 289-304页

作者： zhang le DANG Fa-ning WANG Xu DING Jiu-long GAO Jun zhang Yu School of Civil Engineering and Architecture Xi’an University of TechnologyXi’an 710048China State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi’an University of TechnologyXi’an 710048China Shaanxi Key Laboratory of Loess Mechanics and Engineering Xi’an University of TechnologyXi’an 710048China

The earth pressure acting on retaining walls due to creep and consolidation is under limited equilibrium conditions(limited displacement). Linear elastic constitutive theory can be applied to determine earth pressure distribution along retaining walls under limited displacement condition. In addition,tangent modulus in Duncan-Chang nonlinear elastic model was introduced to reflect the variations of soil modulus with confining pressure, and boundary strains were derived from Rankine active earth pressure, Rankine passive earth pressure, static earth pressure and principal stress direction *** to the above four boundary strains, earth pressure on retaining walls was divided into five state zones. By comparing the calculation results obtained from the equations proposed in this paper with those of experimental tests, the following conclusions can be drawn: earth pressure distribution was always nonlinear along retaining walls for translation displacement(T mode), rotation displacement around wall base(RB mode), and translation + rotation displacement around wall base(RBT mode). Also,calculated earth pressure distributions along with the depth of wall were found to be consistent with measured values under three displacement ***, a parametric study was carried out to evaluate the effects of internal friction angle and backfill soil cohesion on earth pressure. It could be seen from the above series of studies that the earth pressure equations derived in this work could be well applied in practical engineering in designing retaining walls.

关键词： Linear elasticity Limited earth pressure Translation displacement Rotation displacement around wall base Rotation displacement Earth pressure state zone

Improving schedule adherence based on dynamic signal control and speed guidance in connected bus system

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Journal of Intelligent and Connected Vehicles 2020年第2期3卷 79-88页

作者： Mingjie Hao Yiming Bie le zhang Chengyuan Mao School of Transportation Jilin UniversityChangchunChina School of Economics and Management Nanjing University of Science and TechnologyNanjingChina College of Engineering Zhejiang Normal UniversityJinhuaChina

Purpose–The purpose of this paper is to develop a dynamic control method to improve bus schedule adherence under connected bus ***/methodology/approach–The authors developed a dynamic programming model that optimally schedules the bus operating speed at road sections and multiple signal timing plans at intersections to improve bus schedule ***,the bus route was partitioned into three types of sections:stop,road and ***,transit agencies can control buses in real time based on all collected information;*** bus operating speed on road sections and adjust the signal timing plans through signal controllers to improve the schedule adherence in connected bus ***,bus punctuality at the downstream stop and the saturation degree deviations of intersections were selected as the evaluation criteria in optimizing signal control plans and bus speeds ***–An illustrative case study by using a bus rapid transit line in Jinan city was performed to verify the proposed *** revealed that based on the proposed strategy,the objective value could be reduced by 73.7%,which indicated that the punctuality was highly improved but not to incur excessive congestion for other vehicular trafﬁ***/value–In this paper,the authors applied speed guidance and the adjustment of the signal control plans for multiple cycles in advance to improve the scheduled stability;furthermore,the proposed control strategy can reduce the effect on private trafﬁcs to the utmost extend.

关键词： Dynamic programming Speed guidance Connected bus Schedule adherence Signal control

The Impact of Pregnancy Termination before 28 Weeks of Gestation on the Overall Prevalence of Birth Defects-Shaanxi Province,China,2014-2020

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China CDC weekly 2022年第43期4卷 967-973页

作者： Min Li le zhang Lu Gan Zhiwen Li Northwest Women’s and Children's Hospital Xi’an CityShaanxi ProvinceChina Institute of Reproductive and Child Health Peking UniversityBeijingChina Key Laboratory of Reproductive Health National Health Commission of the People’s Republic of ChinaBeijingChina

Introduction:The prevalence of birth defects(BDs)at≥28 gestational weeks in China has declined significantly in recent ***,a few studies have implied that the prevalence is underestimated due to pregnancies with severe BDs often being terminated before 28 weeks of *** study sought to contribute to this data conflict by determining the total prevalence of BDs throughout the entirety of pregnancies,depicting the epidemiological distribution of BDs in Shaanxi Province,and examining the impact of pregnancy termination before 28 weeks of gestation on overall BD ***:Based on data extracted from the provincial Birth Defects Surveillance Network in Shaanxi Province,from 2014 to 2020,the trends of 18 frequent,major BDs at any gestational age were ***:The total prevalence of BDs throughout pregnancy in Shaanxi Province increased significantly from 2014 to 2020,partly due to the inclusion of slight congenital heart *** was also shown that the prevalence of all major types of BD had been previously underestimated,particularly severe external BDs,anywhere from 10%to 100%due to the previous sole measurement of terminations after 28 gestational *** tube defects,however,remained one of the top five BDs with the highest total ***:The exclusion of pregnancy terminationslence of BDs,particularly severe external *** estimate the true population-level prevalence of BD better,the current BD surveillance system should include pregnancy terminations before 28 weeks of gestation.

关键词： termination Impact Defects

Vehicle and charging scheduling of electric bus fleets:A comprehensive review

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Journal of Intelligent and Connected Vehicles 2023年第3期6卷 116-124页

作者： le zhang Yu Han Jiankun Peng Yadong Wang School of Economics and Management Nanjing University of Science and TechnologyNanjing 210094China School of Transportation Southeast UniversityNanjing 211189China

Transit electrification has emerged as an unstoppable force,driven by the considerable environmental benefits it ***,the adoption of battery electric buses is still impeded by their limited flexibility,a constraint that necessitates adjustments to current bus scheduling ***,this study aspires to offer a thorough review of articles focused on battery electric bus ***,we provide a comprehensive review of 42 papers on electric bus scheduling and related studies,with a focus on the most recent developments and trends in this research *** this extensive review,our findings reveal a paucity of research that takes into account the robustness of electric bus ***,we highlight the critical areas of considering diverse charging modes in electric bus scheduling and integrated planning of electric buses,which have not been adequately explored but hold the potential to greatly boost the effectiveness of electric bus *** this synthesis,we hope that readers could acquire a thorough comprehension of the studies in this field and be motivated to address the identified research gaps,thus propelling the progress of transit electrification.

关键词： electric bus vehicle scheduling charging scheduling literature review pptimization

Building the bridge of small organic molecules to porous carbons via ionic solid principle

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Nano Research 2023年第1期16卷 80-87页

作者： lei Tong Qian-Qian Yang Shuai Li le-le zhang Wei-Jie Zeng Yan-Wei Ding Liangdong Fan Hai-Wei Liang Department of New Energy Science and Technology College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060China Hefei National Research Center for Physical Sciences at the Microscale Department of ChemistryUniversity of Science and Technology of ChinaHefei 230026China

Replacing traditional polymer-based precursors with small molecules is a promising pathway toward facile and controllable preparation of porous carbons but remains a prohibitive challenge because of the high volatility of small ***,a simple,general,and controllable method is reported to prepare porous carbons by converting small organic molecules into organic molecular salts followed by *** robust electrostatic force holding organic molecular salts together leads to negligible volatility and thus ensures the formation of carbons under high-temperature ***,metal moieties in organic molecular salts can be evolved into in-situ templates or activators during pyrolysis to create *** modular nature of organic molecular salts allows easy control of the porosity and chemical doping of carbons at a molecular *** sulfur-doped carbon prepared by the ionic solid strategy can serve as robust support to prepare small-sized intermetallic PtCo catalysts,which exhibit a high mass activity of 1.62 A·mgPt^(−1)in catalyzing oxygen reduction reaction for fuel cell applications.

关键词： porous carbon small organic molecules organic molecular salts ionic solid oxygen reduction reaction

Moving research direction in the field of metallic bioresorbable stents-A mini-review

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Bioactive Materials 2023年第6期24卷 20-25页

作者： Xiehui Chen Rong Chang Hongtao Liu le zhang Yufeng Zheng Shenzhen Longhua District Central Hospital&The Affiliated Central Hospital of Shenzhen Longhua District Guangdong Medical UniversityShenzhen518110China School of Materials Science and Engineering Peking UniversityBeijing100871China International Research Organization for Advanced Science and Technology Kumamoto University2-39-2Kumamoto860-8555Japan

In contrast to polymer bioresorbable stents(BRS)that exhibited suboptimal performance in clinical trials due to their deficient mechanical properties,metallic BRS with improved mechanical strength have made their way into the clinic and have demonstrated more promising *** the roadmap of research and development of metallic BRS,magnesium and iron based biodegradable metal stents had been clinically used,and the zinc based biodegradable metal stents had been trailed in *** this mini-review paper,we demonstrate the current technology levels and point out the future R&D direction of metallic *** based BRS should target for decreasing struct thickness meanwhile balancing with enough supporting *** based BRS should move towards high efficient absorption,conversion,metabolism,elimination of its degradation *** based BRS should strive to improve mechanical stability,creep resistance and *** R&D directions of metallic BRS should move towards new materials such as Molybdenum,intelligent stent integrated with degradable biosensors,and new stent with multiple biofunctions,such as NO release.

关键词： Bioresorbable stents Magnesium Iron Zinc Molybdenum

Dissolution-regrowth synthesis of SiO_2 nanoplates and embedment into two carbon shells for enhanced lithium-ion storage

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Chinese Journal of Chemical Engineering 2018年第7期26卷 1522-1527页

作者： Zhijun Yan Xiangcun Li Xiaobin Jiang le zhang Yan Dai Gaohong He State Key Laboratory of Fine Chemicals Chemical Engineering Department Dalian University of Technology

In this work, SiO2 nanoplates with opened macroporous structure on carbon layer （C-mSiO2） have been obtained by dissolving and subsequent ingrowing the outer solid SiO2 layer of the aerosol-based C-SiO2 double-shell hollow spheres. Subsequently, triple-shell C-mSiO2-C hollow spheres were successfully prepared after coating the C- mSiO2 templates by the carbon layer from the carbonization of sucrose. When being applied as the anode material fur lithium-ion batteries, the C-mSiO2-C triple-shell hollow spheres deliver a high capacity of 501 mA. h.g- 1 after 100 cycles at 500 mA.g-1 （based on the total mass of silica and the two carbon shells）, which is higher than those of C-mSiO2 （391 mA.h.g 1） spheres with an outer porous SiO2 layer, C-SiO2-C （370 mA-h.g-1） hollow spheres with a middle solid Si02 layer, and C-SiO2 （319.8 mA·h-g-1） spheres with an outer solid SiO2 layer. In addition, the battery still delivers a high capacity of 403 mA· h· g- 1 at a current density of 1000 mA· g- 1 after 400 cycles. The good electrochemical performance can be attributed to the high surface area （246.7 m2·g- 1 ） and pore volume （0.441 cm3· g-1） of the anode materials, as well as the unique structure of the outer and inner carbon layer which not only enhances electrical conductivity, structural stability, but buffers volume change of the intermediate SiO2 layer during repeated charge-discharge processes. Furthermore, the SiO2 nanoplates with opened macroporous structure facilitate the electrolyte transport and electrochemical reaction.

关键词： Silica nanoplates Carbon shell Macroporous Lithium-ion battery

Synthesis and characterization of Fe_3O_4@SiO_2 magnetic composite nanoparticles by a one-pot process

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International Journal of Minerals,Metallurgy and Materials 2016年第9期23卷 1112-1118页

作者： le zhang Hui-ping Shao Hang Zheng Tao Lin Zhi-meng Guo Institute for Advanced Materials and Technology University of Science and Technology Beijing

Fe3O4@SiO2 core–shell composite nanoparticles were successfully prepared by a one-pot process. Tetraethyl-orthosilicate was used as a surfactant to synthesize Fe3O4@SiO2 core–shell structures from prepared Fe3O4 nanoparticles. The properties of the Fe3O4 and Fe3O4@SiO2 composite nanoparticles were studied by X-ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, and Fourier transform infrared spectroscopy. The prepared Fe3O4 particles were approximately 12 nm in size, and the thickness of the SiO2 coating was approximately 4 nm. The magnetic properties were studied by vibrating sample magnetometry. The results show that the maximum saturation magnetization of the Fe3O4@SiO2 powder（34.85 A·m^2·kg^–1） was markedly lower than that of the Fe3O4 powder（79.55 A·m^2·kg^–1）, which demonstrates that Fe3O4 was successfully wrapped by SiO2. The Fe3O4@SiO2 composite nanoparticles have broad prospects in biomedical applications; thus, our next study will apply them in magnetic resonance imaging.

关键词： composite materials magnetite nanoparticles iron oxides silicon dioxide one-pot process

A Review on Swarm Intelligence and Evolutionary Algorithms for Solving Flexible Job Shop Scheduling Problems

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IEEE/CAA Journal of Automatica Sinica 2019年第4期6卷 904-916页

作者： Kaizhou Gao Zhiguang Cao le zhang Zhenghua Chen Yuyan Han Quanke Pan IEEE the Macao Institute of Systems Engineering at Macao University of Science and Technology 999078 China School of Computer at Liaocheng Univeristy Liaocheng252059China the Department of Industrial Systems Engineering and Management National University of SingaporeSingapore Centre for Maritime Studies National University of SingaporeSingapore the Institute for Infocomm Research(I2R) the Agency for ScienceTechnology and Research(A*STAR)Singapore the School of Computer at Liaocheng Univeristy Liaocheng 252059China School of Mechatronic Engineering and Automation Shanghai UniversityShanghai 200072China

Flexible job shop scheduling problems(FJSP)have received much attention from academia and industry for many *** to their exponential complexity,swarm intelligence(SI)and evolutionary algorithms(EA)are developed,employed and improved for solving *** than 60%of the publications are related to SI and *** paper intents to give a comprehensive literature review of SI and EA for solving ***,the mathematical model of FJSP is presented and the constraints in applications are ***,the encoding and decoding strategies for connecting the problem and algorithms are *** strategies for initializing algorithms?population and local search operators for improving convergence performance are ***,one classical hybrid genetic algorithm(GA)and one newest imperialist competitive algorithm(ICA)with variables neighborhood search(VNS)for solving FJSP are ***,we summarize,discus and analyze the status of SI and EA for solving FJSP and give insight into future research directions.

关键词： Evolutionary algorithm flexible job shop scheduling review swarm intelligence