检索结果-南通市图书馆

Independent directors' board networks and controlling shareholders' tunneling behaviorq

在线全文

学校读者我要写书评

暂无评论

China Journal of Accounting Research 2014年第2期7卷 101-118页

作者： Yunsen Chen Yutao Wang Le Lin School of Accountancy Central University of Finance and EconomicsChina School of Economics and Management Tsinghua UniversityChina

As one of the channels by which board directors build important relationships,board networks can affect the governance role of independent directors. Defining director board networks as their connections based on direct ties they establish when serving on at least one common board, this paper explores the role of the network centrality of independent directors in restraining tunneling behavior by controlling shareholders in the Chinese capital market.Our empirical evidence shows that tunneling behavior by controlling shareholders is negatively related to the network centrality of independent directors and that this relationship is stronger when non-operating fund occupation is used as the measure of tunneling. The results of our study show that board networks can help independent directors to restrain tunneling behavior by large shareholders, which plays a positive role in corporate governance.ó 2013 Production and hosting by Elsevier B.V. on behalf of China Journal of Accounting Research. Founded by Sun Yat-sen University and City University of Hong Kong.

关键词： Network Independent director Tunneling Socialnetwo

Microstructure and mechanical properties of Fe/NbC composite layer prepared by in-situ reaction

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Foundry 2023年第4期20卷 356-364页

作者： le Chen Ji-lin Li Meng-jun Wang Jie Zheng Yao Zhu Zhuo-lin Liu Bing-gui Lü School of Materials Science and Engineering Central South UniversityChangsha 410083China School of Materials Science and Engineering Xi'an University of TechnologyXi'an 710048China Institute of New Materials Guangdong Academy of SciencesGuangzhou 510650China Guangdong Provincial Key Laboratory of Metal Toughening Technology and Application Guangzhou 510650China Guangdong Guangyun New Material Co. Ltd.Yunfu 527527GuangdongChina Yunfu Guangyun Technology R&D Co. Ltd.Yunfu 527527GuangdongChina

NbC ceramic surface-reinforced steel matrix composites were prepared by an in-situ reaction method at different temperatures(1,050℃,1,100℃and 1,150℃)for different times(1 h,2 h and 3 h).The phase constitution,microstructure and fracture morphology of NbC ceramic surface-reinforced steel matrix composites were analyzed by XRD,SEM and EDS,and the effects of the in-situ reaction temperature and time on the mechanical properties were systematically studied.The results indicate that the NbC reinforcement layer is formed through the reaction between Nb atoms and carbon atoms diffused from the steel matrix to the Nb plate.The thickness of this reinforcement layer increases as the reaction time prolongs.Additionally,an increase in reaction temperature results in a thicker reinforcement layer,although the rate of increase gradually decreases.The relationship among the thickness of the Nb C reinforcement layer,the reaction time and temperature was established by data fitting.The optimal tensile performance is achieved at 1,100℃for 1 h,with a tensile strength of 228 MPa.It is also found that the defects between the reinforcement layer and the steel matrix are related to reaction temperature.At 1,100℃,these defects are minimal.Fracture mostly occurs in the NbC reinforced layer of the composites,and the fracture mode is characterized by typical intergranular brittle fracture.

关键词： in-situ reaction NbC reinforcement layer microstructure mechanical property

A novel modification method for the dynamic mechanical test using thermomechanical analyzer for composite multi-layered energetic materials

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2023年第3期21卷 125-132页

作者： le Qi Shi-lin Zhang Hao Yuan Zhong-liang Ma Zhong-liang Xiao School of Environment and Safety Engineering The North University of ChinaTaiyuan030051China School of Chemical Engineering The Nanjing University of Science and TechnologyNanjing210094China

Herein,we present a thermo-mechanical analyzer(TMA)and dynamic mechanical analyzer(DMA)of composite multi-layered gun propellant,focusing on thermal expansion coefficients and dynamic thermomechanical properties.The linear thermal expansion coefficient of the prepared energetic material is determined as approx.0.1800×10^(-4)-0.2081×10^(-4)K^(-1).According to DMA test and dynamic thermomechanical properties,the glass transition temperature is also obtained.The tested value is within the range of 223.01-223.50 K,which indicates the lower limit of the energetic material.However,DMA tests reveal temperature changes,which occur due to thermal expansion.Moreover,the geometrical factor decreases with increasing temperature.Therefore,thermal expansion significantly affects the storage modulus and loss modulus.Additionally,the thermal expansion coefficient can be used to modify the storage and loss modulus.The results show that the proposed method provides effective and reliable modified results.

关键词： composite dynamic expansion

Effect of shrub encroachment on leaf nutrient resorption in temperate wetlands in the Sanjiang Plain of Northeast China

在线全文

学校读者我要写书评

暂无评论

Ecological Processes 2022年第1期11卷 968-975页

作者： le‑lin Yu Xin‑Hou Zhang Fu‑Xi Shi Rong Mao Key Laboratory of National Forestry and Grassland Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed College of ForestryJiangxi Agricultural UniversityNo.1101 Zhimin RoadNanchang 330045China Key Laboratory of Wetland Ecology and Environment Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102China School of Environment Nanjing Normal UniversityNanjing 210046China

Background:Nutrient resorption is an important plant nutrient conservation strategy in wetlands.However,how shrub encroachment alters plant nutrient resorption processes is unclear in temperate wetlands.Here,we collected green and senesced leaves of common sedge,grass,and shrub species in wetlands with high(50–65%)and low(20–35%)shrub covers in the Sanjiang Plain of Northeast China,and assessed the impact of shrub encroachment on leaf nitrogen(N)and phosphorus(P)resorption efficiency and proficiency at both plant growth form and community levels.Results:The effects of shrub cover on leaf nutrient resorption efficiency and proficiency were identical among shrubs,grasses,and sedges.Irrespective of plant growth forms,increased shrub cover reduced leaf N resorption efficiency and proficiency,but did not alter leaf P resorption efficiency and proficiency.However,the effect of shrub cover on leaf nutrient resorption efficiency and proficiency differed between plant growth form and community levels.At the community level,leaf N and P resorption efficiency decreased with increasing shrub cover because of increased dominance of shrubs with lower leaf nutrient resorption efficiency over grasses and sedges.Accordingly,community‑level senesced leaf N and P concentrations increased with elevating shrub cover,showing a decline in leaf N and P resorption proficiency.Moreover,the significant relationships between leaf nutrient resorption efficiency and proficiency indicate that shrub encroachment increased senesced leaf nutrient concentrations by decreasing nutrient resorption efficiency.Conclusions:These observations suggest that shrub encroachment reduces community‑level leaf nutrient resorp‑tion efficiency and proficiency and highlight that the effect of altered plant composition on leaf nutrient resorption should be assessed at the community level in temperate wetlands.

关键词： Biodiversity Freshwater marsh Nutrient conservation strategy Plant growth form Species composition

Behavioral interventions to eliminate fear responses

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2018年第6期61卷 625-632页

作者： Jingli Yue le Shi Xiao lin Muhammad Zahid Khan Jie Shi lin Lu Peking University Sixth Hospital Peking University Institute of Mental Health Key of Mental Health Ministry of Health (Peking University)National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital) National Institute on Drug Dependence Peking University Peking-Tsinghua Center for Life Sciences and PKU-IDG/Mc Govern Institute for Brain Research Peking University

Fear memory underlies anxiety-related disorders, including posttraumatic stress disorder(PTSD). PTSD is a fear-based disorder,characterized by difficulties in extinguishing the learned fear response and maintaining extinction. Currently, the first-line treatment for PTSD is exposure therapy, which forms an extinction memory to compete with the original fear memory. However,the extinguished fear often returns under numerous circumstances, suggesting that novel methods are needed to eliminate fear memory or facilitate extinction memory. This review discusses research that targeted extinction and reconsolidation to manipulate fear memory. Recent studies indicate that sleep is an active state that can regulate memory processes. We also discuss the influence of sleep on fear memory. For each manipulation, we briefly summarize the neural mechanisms that have been identified in human studies. Finally, we highlight potential limitations and future directions in the field to better translate existing interventions to clinical settings.

关键词：除害行为活跃状态神经机制记忆扑灭存储器操作

Extraction of Cr(Ⅵ) from chromite ore processing residue via hydrothermal-assisted phase transformation

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical letters 2020年第7期31卷 1956-1960页

作者： Xiaofeng Mo Jin Zhou Le Lin Zuqi Zhong Shaohua Yang Xueming Liu Zhenqing Shi Dongye Zhao Zhang lin The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters(Ministry of Education) School of Environment and EnergySouth China University of TechnologyGuangzhou 510006China Sino-Singapore International Joint Research Institute Sino-Singapore Guangzhou Knowledge CityGuangzhou 510006China Environmental Engineering Program Department of Civil EngineeringAuburn UniversityAuburn AL 36849United States

The effective extracting Cr(Ⅵ) from chromite ore processing residue(COPR) is the key to achieve COPR detoxification and recovery.We developed an effective method to extract Cr(Ⅵ) from COPR via controlling the phase transformation of Cr(Ⅵ)-containing minerals.Characteristic analysis showed that Cr(Ⅵ) was mainly incorporated in the hydrocalumite(NaCa4Al2O6(SO4/CrO4)1.5-15H2O) in COPR,which was a layered-double hydroxide(LDH) with multilayer structure.In the hydrothermal treatment experiments,the Na2CO3 solution showed significant extraction effect of Cr(Ⅵ) and detoxification effect of COPR.After treatment,95% of Cr(Ⅵ) was removed and the Cr(Ⅵ) concentration in the leachate was decreased to 1.6 mg/L by the toxicity characteristic leaching procedure(TCLP),within the regulatory limit disposal standard(HJ/T 301-2007,3 mg/L).Further study revealed that,during the treatment,hydrocalumite transformed into calcite(CaCO3) under the effect of mineralizer,therefore,the layered structure collapsed and the incorporated Cr(Ⅵ) was released to the supernatant.Meanwhile,the Cr(Ⅵ)desorbed from calcite with the calcite particles grew into large size with smooth surface.Stir-flow experiment revealed that the amount of chromium released from CORP to the environment was significantly reduced after treatment,and it is safer for landfill disposal.This work will provide an instructive guidance for the detoxification and recovery of COPR.

关键词： Chromite ore processing residue Hexavalent chromium extraction Hydrothermal mineralization Phase transformation

Vagus nerve stimulation is a potential treatment for ischemic stroke

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2023年第4期18卷 825-831页

作者： Yi-lin Liu San-Rong Wang Jing-Xi Ma le-Hua Yu Gong-Wei Jia Department of Rehabilitation The Second Affiliated Hospital of Chongqing Medical UniversityChongqingChina The Second Clinical College Chongqing Medical UniversityChongqingChina Department of Neurology Chongqing General HospitalChongqingChina Chongqing Key Laboratory of Neurodegenerative Diseases ChongqingChina

Microglia are the brain’s primary innate immune cells,and they are activated and affect pro-inflammatory phenotype or regulatory phenotype after ischemic stroke.Vagus nerve stimulation was shown to activate microglial phenotypic changes and exhibit neuroprotective effects in ischemia/reperfusion injury.In this study,we established rat models of ischemic stroke by occlusion of the middle cerebral artery and performed vagus nerve stimulation 30 minutes after modeling.We found that vagus nerve stimulation caused a shift from a pro-inflammatory phenotype to a regulatory phenotype in microglia in the ischemic penumbra.Vagus nerve stimulation decreased the levels of pro-inflammatory phenotype markers inducible nitric oxide synthase and tumor necrosis factorαand increased the expression of regulatory phenotype markers arginase 1 and transforming growth factorβthrough activatingα7 nicotinic acetylcholine receptor expression.Additionally,α7 nicotinic acetylcholine receptor blockade reduced the inhibition of Toll-like receptor 4/nuclear factor kappa-B pathwayassociated proteins,including Toll-like receptor 4,myeloid differentiation factor 88,I kappa B alpha,and phosphorylated-I kappa B alpha,and also weakened the neuroprotective effects of vagus nerve stimulation in ischemic stroke.Vagus nerve stimulation inhibited Toll-like receptor 4/nuclear factor kappa-B expression through activatingα7 nicotinic acetylcholine receptor and regulated microglial polarization after ischemic stroke,thereby playing a role in the treatment of ischemic stroke.Findings from this study confirm the mechanism underlying vagus nerve stimulation against ischemic stroke.

关键词： cerebral ischemia microglia neuroprotection nuclear factor kappa-B pro-inflammatory phenotype regulatory phenotype reperfusion Toll-like receptor 4 vagus nerve stimulation α7 nicotinic acetylcholine receptor

Effect of Al_(2)O_(3)/Na_(2)O ratio and MnO on high-temperature properties of mold flux for casting peritectic steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2022年第1期29卷 53-60页

作者： le-jun Zhou Hao Luo Wan-lin Wang Xiong Yan Hou-fa Wu School of Metallurgy and Environment Central South UniversityChangsha 410083HunanChina National Center for International Cooperation of Clean Metallurgy Changsha 410083HunanChina

The influences of Al_(2)O_(3)/Na_(2)O ratio and MnO content on high-temperature properties,such as melting,crystallization,heat transfer,and viscosity of mold flux for casting peritectic steel,have been investigated.The results show that the melting temperatures of mold flux decrease,whereas the ratio of crystalline layers increases with the decrease in Al_(2)O_(3)/Na_(2)O ratio and increase in MnO content.The average response temperatures of the three mold fluxes decrease from 566,525,to 512℃,respectively,which indicates that the heat transfer controlling ability of mold flux is promoted due to the increase in crystallization ability and addition of transition metal oxide MnO.Furthermore,the viscosity-temperature curves suggest that the viscosity at 1300℃ decreases,but the break temperature increases with the reduction in Al_(2)O_(3)/Na_(2)O and addition of MnO.

关键词： Mold flux Peritectic steel Melting Crystallization Heat transfer Viscosity

Real-time and visible monitoring of stress distribution using organic mechanoresponsive luminogen

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2021年第12期64卷 2586-2594页

作者： ZHANG le ZHANG Zhe lin Hong CHEN Gang CHEN Xu School of Chemical Engineering and Technology Tianjin UniversityTianjin 300350China Tianjin Key Laboratory of Chemical Process Safety and Equipment Technology Tianjin 300350China

A real-time and visible stress monitoring method based on a pure organic mechanoresponsive luminogen(MRL)was proposed in this work.1,1,2,2-tetrakis(4-nitrophenyl)ethene(TPE-4 N)could produce ultrasensitive and visible mechanoresponsive fluorescence.Metal specimens were coated with a uniform TPE-4 N film,wherein mechanical deformation was transformed into visible fluorescence.Tensile tests were conducted to determine the calibration relationship between the stress value and fluorescence intensity.The accuracy of stress measured using the organic MRL method was investigated on single-edge notched tension specimens.Results show that the stress distribution obtained using the proposed method agrees well with that calculated using ANSYS simulation.The organic MRL method may open up new opportunities for large-scale,full-field,on-site monitoring of stress distribution in complicated structural components.

关键词： stress measurement real-time monitoring organic mechanoluminescence