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Few-layer Tellurium:one-dimensional-like layered elementary semiconductor with striking physical properties

science Bulletin 2018年第3期63卷 159-168页

作者： Jingsi Qiao Yuhao Pan Feng yang Cong Wang yang Chai Wei Ji Beijing Key laboratory of Optoelectronic Functional Materials & Micro-Nano Devices Department of Physics Renmin University of China Department of Applied Physics The Hong Kong Polytechnic University

Few-layer Tellurium, an elementary semiconductor, succeeds most of striking physical properties that black phosphorus(BP) offers and could be feasibly synthesized by simple solution-based methods. It is comprised of non-covalently bound parallel Te chains, among which covalent-like feature *** feature is, we believe, another demonstration of the previously found covalent-like quasi-bonding(ClQB) where wavefunction hybridization does occur. The strength of this inter-chain ClQB is comparable with that of intra-chain covalent bonding, leading to closed stability of several Te allotropes. It also introduces a tunable bandgap varying from nearly direct 0.31 eV(bulk) to indirect 1.17 eV(2l) and four(two) complex, highly anisotropic and layer-dependent hole(electron) pockets in the first Brillouin *** also exhibits an extraordinarily high hole mobility(~10~5 cm^2/Vs) and strong optical absorption along the non-covalently bound direction, nearly isotropic and layer-dependent optical properties, large ideal strength over 20%, better environmental stability than BP and unusual crossover of force constants for interlayer shear and breathing modes. All these results manifest that the few-layer Te is an extraordinary-high-mobility, high optical absorption, intrinsic-anisotropy, low-cost-fabrication, tunable bandgap, better environmental stability and nearly direct bandgap semiconductor. This ‘‘one-dimen sion-like" few-layer Te, together with other geometrically similar layered materials, may promote the emergence of a new family of layered materials.

关键词： Two-dimensional systems First-principles calculations Tellurium High carrier mobility Covalent-like quasi-bonding One-dimension-like layered materials

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Physiological mechanism underlying spikelet degeneration in rice

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Journal of Integrative Agriculture 2018年第7期17卷 1475-1481页

作者： WANG Zhi-qin ZHANG Wei-yang yang Jian-chang Key laboratory of Crop Genetics and Physiology of Jiangsu Province/Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province Yangzhou University

The phenomenon of degenerated spikelets is very common in cereals, and considered as a serious physiological defect and a main constraint to grain production. Understanding the physiological mechanism in which spikelet degeneration occurs would have great significance in enhancing yield potential in grain crops. Taking rice as an example, the paper reviewed the physiological mechanism underlying spikelet degeneration, with focus on the roles of phytohormones in regulating the process. There are several hypotheses for the spikelet degeneration, such as resource limitation, self-organization, and primigenic dominance. However, convincing evidences are not enough to support the assumptions. Phytohormones including auxins, cytokinins, gibberellins, abscisic acid, and ethylene are involved in regulating spikelet degeneration in cereals. The new phytohormones of brassinosteroids and polyamines have been observed to suppress spikelet degeneration in rice. The interactions among or between plant hormones may play a more important role in regulating spikelet degeneration. However, the information on such interactions is very limited. some agronomic practices, especially proper water and nitrogen management, could reduce spikelet degeneration but the mechanism underlying remains unclear. Further research is needed to understand the cross-talk among/between phytohormones on spikelet degeneration, to reveal the physiological and molecular mechanism in which phytohormones and their interactions regulate the degeneration of spikelets, to exploit approaches to decrease spikelet degeneration and to elucidate their mechanism.

关键词： rice(Oryza safiva) spikelet degeneration phytohormones brassinosteroids polyamines

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Epidemiology and natural history of hepatitis C virus infection

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World Journal of Gastroenterology 2014年第28期20卷 9270-9280页

作者： Mei-Hsuan lee Hwai-I yang Yong Yuan Gilbert l’Italien Chien-Jen Chen the Institute of Clinical Medicine National Yang-Ming University the Genomics Research Center Academia Sinica the Graduate Institute of Clinical Medical science China Medical University the Molecular and Genomic Epidemiology Center China Medical University Hospital the Global Health Economics and Outcomes Research Bristol-Myers SquibbPrincetonNJ 08543United States the Yale University school of Medicine the Graduate Institute of Epidemiology and Preventive Medicine College of Public HealthNational Taiwan University

Hepatitis C virus(HCV)affects 130-210 million people worldwide and is one of the major risk factors for hepatocellular ***,at least one third of hepatocellular carcinoma cases are attributed to HCV infection,and 350000 people died from HCV related diseases per *** is a great geographical variation of HCV infection globally,with risk factors for the HCV infection differing in various *** progression of chronic hepatitis C to end-stage liver disease also varies in different study populations.A long-term follow-up cohort enrolling participants with asymptomatic HCV infection is essential for elucidating the natural history of HCV-caused hepatocellular carcinoma,and for exploring potential seromarkers that have high predictability for risk of hepatocellular ***,prospective cohorts comprising individuals with HCV infection are still *** risk evaluation of viral load elevation and associated liver disease/cancer in HCV(REVEAl-HCV)study has followed a cohort of 1095 residents seropositive for antibodies against hepatitis C virus living in seven townships in Taiwan for more than fifteen *** of them have acquired HCV infection through iatrogenic transmission *** the participants in the REVEAlHCV study rarely receive antiviral therapies,it provides a unique opportunity to study the natural history of chronic HCV *** this review,the prevalence,risk factors and natural history of HCV infection are comprehensively *** study cohort,data collection,and findings on liver disease progression of the REVEAl-HCV study are described.

关键词： Hepatitis C virus Epidemiology Risk evaluation of viral load elevation and associated liver disease/cancer long-term liver progression

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A new landing impact attenuation seat in manned spacecraft biologically-inspired by felids

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Chinese Journal of Aeronautics 2015年第2期28卷 434-446页

作者： Yu Hui Zhang Zhiqiang liu Hua yang Jialing Wang lili yang liming Institute of solid Mechanics School of Aeronautic Science and Engineering Beihang University Mechanics and Materials science Research Center Faculty of Mechanical Engineering and Mechanics Ningbo University

When manned spacecraft comes back to the earth, it relies on the impact attenuation seat to protect astronauts from injuries during landing phase. Hence, the seat needs to transfer impact load, as small as possible, to the crew. However, there is little room left for traditional seat to improve further. Herein, a new seat system biologically-inspired by felids＇ landing is proposed. Firstly, a series of experiments was carried out on cats and tigers, in which they were trained to jump down voluntarily from different heights. Based on the ground reaction forces combined with kinematics, the experiment indicated that felids＇ landing after self-initial jump was a multi-step impact attenuation process and the new seat was inspired by this. Then the construction and work process of new seat were redesigned to realize the multi-step impact attenuation. The dynamic response of traditional and new seat is analyzed under the identical conditions and the results show that the new concept seat can significantly weaken the occupant overload in two directions compared with that of traditional seat. As a consequence, the risk of injury evaluated for spinal and head is also lowered, meaning a higher level of protection which is especially beneficial to the debilitated astronaut.

关键词： Astronautics Bionics Impact attenuation landing Overload seat

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Effect of Heat Treatment on Prior Grain size and Mechanical Property of a Maraging stainless steel

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Journal of Materials science & Technology 2006年第6期22卷 769-774页

作者： Kai lIU Yiyin sHAN Zhiyong yang Jianxiong lIANG lun lU Ke yang Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Graduate school of Chinese Academy of sciences Beijing 100039 China General Research Institute for Iron and steel Beijing 100081 China Technical Center Dongbei Special Steel Group Co. Fushun 113001 China

Effect of the heat treatment, including solution treatment （sT） and aging treatment （AT）, on the prior austenite grain （PAG） size, microstructure and mechanical properties of a precipitation hardening maraging stainless steel was investigated. The results indicate that the relations between PAG size and yield strength （σy） under both sT and AT conditions obey the HalI-Petch relationship. Furthermore, after sT at 1050℃ for 1 h＋cryogenic treated （CT） at -70℃ for 8 h＋AT at 535℃ for 4 h, the tested steel showed its ultimate tensile strength （σb） and σy over 1900 MPa and 1750 MPa, respectively.

关键词： Martensite Microstructure Precipitation hardening Heat treatment

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Numerical simulation and Experimental Verification of the stiffness and stability of Thrust Pad Aerostatic Bearings

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Chinese Journal of Mechanical Engineering 2018年第2期31卷 186-197页

作者： Hai-long Cui yang Wang Bao-Rui Wang Hong yang Huan Xia Institute of Mechinery Manufacturing Technology China Academy of Engineering Physics

Many researchers concentrate on improving the stiffness and stability of aerostatic bearings, however the contradiction between stiffness and stability is still existed. Therefore, orifice, multiple, and porous restrictors are designed to illustrate the influence of restrictor characteristics on the stability and stiffness of the aerostatic circular pad bearings. Because both the stiffness and stability of aerostatic bearings are determined by the internal pressure distribution, the full Navier?stokes(N?s) equations are applied to solve internal pressure distribution in bearing film by using computational fluid dynamics(CFD) method. simulation results present that the stiffness and stability of aerostatic circular pad bearings are influenced significantly by geometrical and material parameters, such as film thickness, orifice diameters, and viscous resistance coe cient. Verified by the experimental data, the micro vibration of orifice restrictor is almost the same as multiple restrictors with amplitude of 0.02 m/s~2, but it is much stronger than the porous restrictors with acceleration of 0.006 m/s~2. The optimal stiffness of multiple restrictors increased by 46%, compared to only 30.2 N/μm of orifice restrictor, and the porous restrictors had obvious advantage in the small film thickness less than 6 μm where the optimal stiffness increased to 38.3 N/μm. The numerical and experimental results provide guidance for improving the stiffness and stability of aerostatic bearings.

关键词： Aerostatic bearings CFD Restrictor characteristics stability and stiffness

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A new fluorocarbon adhesive:Inhibiting agglomeration during combustion of propellant via efficient F-Al_(2)O_(3) preignition reaction

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Carbon Energy 2024年第6期6卷 292-305页

作者： Qifa Yao Min Xia Chao Wang Fanzhi yang Wei yang Yunjun luo school of Materials science and Engineering Beijing Institute of TechnologyBeijingChina Key laboratory of High Energy Density Materials Ministry of EducationBeijing Institute of TechnologyBeijingChina school of Aerospace Engineering Beijing Institute of TechnologyBeijingChina Advanced Research Institute of Multidisciplinary science Beijing Institute of TechnologyBeijingChina

Inhibiting the agglomeration of molten aluminum particles packed in the binder network is a promising scheme to achieve efficient combustion of solid *** this investigation,the hydroxyl-terminated structured fluorinated alcohol compound(PFD)was introduced to modify the traditional polyethylene glycol/polytetrahydrofuran block copolymerization(HTPE)binder;that is,a unique fluorinated polyether(FTPE)binder was synthesized by embedding fluorinated organic segments into the HTPE binder via crosslinking *** FTPE was applied in aluminum-based propellants for the first *** to the complete release of fluorinated organic active segments in the range of 300℃to 400℃,the burning rate of FTPEbased propellant increased from 4.07(0%PFD)to 6.36 mm/s(5%PFD),increased by 56.27%under 1 *** reaction heat of FTPE propellants increased from 5.95(0%PFD)to 7.18 MJ/kg(5%PFD)under 3.0 MPa,indicating that HTPE binder modified with PFD would be conducive to inhibiting the D90 of condensed combustion products(CCPs)dropped by 81.84%from 75.46(0%PFD)to 13.71μm(5%PFD)under 3.0 MPa,in consistent with the significant reduction of aluminum agglomerates observed on the quenched burning surface of the *** results demonstrated that a novel FTPE binder with PFD can release fluorinated organic active segments,which motivate preignition reaction with the alumina shell in the early stage of aluminum combustion,and then enhance the melting diffusion effect of aluminum to inhibit the agglomeration.

关键词： agglomeration characteristics aluminum particles combustion fluorine alcohol compounds HTPE propellants

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区域对外服务能力、要素流动与经济协调发展

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工业技术经济 2025年第3期44卷 120-129页

作者：陈丽娴阳扬广东外语外贸大学经济贸易学院广州510006 广东外语外贸大学粤港澳大湾区研究院广州510006 中共广西区委党校(广西行政学院)经济学教研部南宁530021

区域对外服务能力提高是否有助于区域间生产要素的相互协调和高效配置,进而显著推动了区域经济协调发展。为回答这一问题,本文从理论分析和实证检验两方面探究区域对外服务能力对区域经济协调发展的影响效应和作用机制。研究结果显示:... 详细信息

区域对外服务能力提高是否有助于区域间生产要素的相互协调和高效配置,进而显著推动了区域经济协调发展。为回答这一问题,本文从理论分析和实证检验两方面探究区域对外服务能力对区域经济协调发展的影响效应和作用机制。研究结果显示:区域对外服务能力对区域经济协调发展的影响呈现倒“U”型。影响机制分析发现,区域对外服务能力通过提高区域间劳动力要素流动和资本要素流动对区域经济协调发展发挥正向作用。异质性分析发现,东部、中西部地区对外服务能力对区域经济协调发展的影响均为倒“U”型,且不存在组间差异;区域对外供给高端服务要素对区域经济协调发展的作用效果显著大于区域对外供给低端服务要素的作用效果。

关键词：区域对外服务能力劳动力要素流动资本要素流动区域经济协调发展产业结构地理位置生产性服务业

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Model and application of bidirectional pedestrian flows at signalized crosswalks

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Chinese Physics B 2018年第7期27卷 606-618页

作者： Tao Zhang Gang Ren Zhi-Gang Yu yang yang Jiangsu Key laboratory of Urban ITs Southeast UniversityNanjing 210096China

This research of bidirectional pedestrian flows at signalized crosswalks is divided into two parts： model and applica- tion. In the model part, a mixed survey including the questionnaire investigation and tracking investigation is conducted to gain the basic data about walking tendentiousness of a pedestrian crossing. Then, the forward, right-hand, outstripping, and influential coefficients are outlined to quantize walking tendentiousness of pedestrian crossing and estimate transition probabilities of pedestrians. At last, an improved cellular automation model is proposed to describe walking tendentious- ness and crossing behaviors of pedestrians. In the application part, channelization research of bidirectional pedestrian flows is presented for real signalized crosswalk. In this process, the effects of right-side-walking and conformity behaviors on the efficiency of pedestrian crossing are thoroughly analyzed based on simulations and experiments to obtain a final channelization method to raise the efficiency of a pedestrian crossing at the crosswalk.

关键词： pedestrian flows right-side-walking behavior conformity behavior simulation

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sediment loads response to climate change:A preliminary study of eight large Chinese rivers

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International Journal of sediment Research 2013年第1期28卷 1-14页

作者： X.X.lU l.s.RAN s.lIU T.JIANG s.R.ZHANG J.J.WANG Department of Geography National University of Singapore117570Singapore Global Change and Watershed Management Center Yunnan University of Finance and EconomicsYunnan National Climate Centre China Meteorological AdministrationBeijingChina College of Water sciences Beijing Normal UniversityChina

Climate change characterized by increasing temperature is able to affect precipitation regime and thus surface ***,the manner in which river sediment loads respond to climate change is not well understood,and related assessment regarding the effect of climate change on sediment loads is *** present a quantitative estimate of changes in sediment loads(from 1.5 Gt yr-1pre-1990 to 0.6 Gt yr-1from 1991-2007) in response to climate change in eight large Chinese *** the past decades,precipitation change coupled with rising temperatures has played a significant role in influencing the sediment delivery dynamics,although human activities, such as reservoir construction,water diversion,sand mining and land cover change,are still the predominant forces. lower precipitation coupled with rising temperatures has significantly reduced sediment loads delivered into the sea in semi-arid climates(4-61%).In contrast,increasingly warmer and wetter climates in subtropical zones has yielded more sediment(0.4-11%),although the increase was offset by human *** results indicate that,compared with mechanical retention by reservoirs,water reduction caused by climate change or human withdrawals has contributed more sediment reduction for the rivers with abundant sediment supply but limited transport capacity(e.g.,the Huanghe).Furthermore,our results indicate that every 1%change in precipitation has resulted in a 1.3%change in water discharge and a 2%change in sediment *** addition,every 1%change in water discharge caused by precipitation has led to a 1.6%change in sediment loads,but the same percentage of water discharge change caused largely by humans would only result in a 0.9%change in sediment *** figures can be used as a guideline for evaluating the responses of sediment loads to climate change in similar climate zones because future global warming will cause dramatic changes in water and sediment in river basins worldwide at rates previou

关键词： sediment load Climate change Human activity Water withdrawal Chinese rivers

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