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Electrochemical borylation of nitroarenes

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Science China Chemistry 2023年第2期66卷 534-539页

作者： Linlin Du Binfeng zhang Shuohan Ji Hu Cai hua zhang Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education&Hubei Key Laboratory of Catalysis and Materials Science School of Chemistry and Materials ScienceSouth-Central Minzu UniversityWuhan430074China School of Chemistry and Chemical Engineering Nanchang UniversityNanchang330031China

A simple electrochemically mediated method for the conversion of nitroarenes to aryl boronic esters is *** borylation of a diverse range of nitroarenes,including the late-stage borylation of bioactive molecules,is furnished at room temperature under simple conditions,thereby demonstrating the broad utility and functional-group tolerance of this *** transformation provides a convenient and practical access to aryl boronic esters from widely available nitroarenes,which would significantly streamline the synthetic process of diverse functionalized arenes.

关键词： electrochemistry borylation nitroarenes arylboronic esters organic synthesis

Enriched environment upregulates growth-associated protein 43 expression in the hippocampus and enhances cognitive abilities in prenatally stressed rat offspring

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Neural Regeneration Research 2012年第25期7卷 1967-1973页

作者： Zhengyu zhang hua zhang Baoling Du Zhiqiang Chen Department ofHistologyand Embryology Guangzhou Medical University Guangzhou 510185 Guangdong Province China Department of Stomatology First Affiliated Hospital Jinan University Guangzhou 510630 Guangdong Province China Department of Orthopedics Surgery Liaocheng People's Hospital Liaocheng 252000 Shandong Province China

In our previous study, we reported that prenatal restraint stress could induce cognitive deficits, which correlated with a change in expression of growth-associated protein 43 in the hippocampus. In this study, we investigated the effects of enriched environment on cognitive abilities in prenatally stressed rat offspring, as well as the underlying mechanisms. Reverse transcription-PCR and western blot assay results revealed that growth-associated protein 43 mRNA and protein levels were upregulated on postnatal day 15 in the prenatal restraint stress group. Growth-associated protein 43 expression was significantly lower in the prenatal restraint stress group compared with the negative control and prenatal restraint stress plus enriched environment groups on postnatal days 30 and 50. Morris water maze test demonstrated that cognitive abilities were noticeably increased in rats from the prenatal restraint stress plus enriched environment group on postnatal day 50. These results indicate that enriched environment can improve the spatial learning and memory ability of prenatally stressed offspring by upregulating growth-associated protein 43 expression.

关键词： prenatal restraint stress growth-associated protein 43 hippocampus Morris water maze enrichedenvironment cognition neural regeneration

Thermal analysis of walls in a new-type billet caster tundish with a vacuum shell

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Journal of Iron and Steel Research International 2017年第5期24卷 501-507页

作者： Jian-bo Xie Jian-an Zhou Lan-hua Zhou Bao Wang hua zhang State Key Laboratory of Refractories & Metallurgy Wuhan University of Science & Technology Wuhan 430081 Hubei China Key Laboratory of Ferrous Metallurgy and Resources Utilization Ministry of Education Wuhan University of Science & Technology Wuhan 430081 Hubei China School of Resources and Environmental Engineering Panzhihua University Panzhihua 617000 Sichuan China

To reduce thermal loss from molten steel in a tundish during continuous casting production, a new tundish fabricated by welding radiation-proof steel plates onto the steel plates of the exterior walls of a billet caster tundish was proposed. This new tundish was used to investigate the effect of pressures inside the vacuum chamber on the uniformity of the temperature of molten steel and the thermal conditions of the vacuum layer. The results show that the conversion radiation coefficient is not sensitive to pressure and its value at high temperatures is merely 1.5 times greater than that at low temperatures. Pressure is the key factor af- fecting additional factor of conversion convection. This factor is more than 100 times greater at 10-5 Pa than at 10-2 Pa, and the temperature at inner points at 10-2 Pa is, on average, 4 K higher than that at 10-5 Pa. Meanwhile, the local temperature difference of the inlet at 10-2 Pa is 1 K higher than that at 10-5 Pa. Thus, the proposed vacuum billet caster tundish can achieve low superheat teeming of steel because of the ther- mal preservation capability of the vacuum, which helps to reduce the tapping temperature and improve the uniformity of the temperature of steel.

关键词： Tundish Vacuum chamber Pressure Thermal preservation Superheat

Piezoelectric Actuator Placement Optimization and Active Vibration Control of a Membrane Structure

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Acta Mechanica Solida Sinica 2018年第1期31卷 66-79页

作者： Xiang Liu Guoping Cai Fujun Peng hua zhang Department of Engineering Mechanics State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai 200240 China Shanghai Institute of Aerospace System Engineering Shanghai 201109 China

The placement optimization of piezoelectric actuators and active vibration control of a membrane structure are studied in this paper. The classical linear quadratic regulator con- trollers are designed to suppress the unwanted vibration. Simulation results indicate that the optimal locations of piezoelectric actuators are affected deeply by the additional mass and stiff- ness of actuators, the computational efficiency of particle swarm optimizer is higher than that of genetic algorithm for this particular problem, and the control performance of optimally placed actuators is better than that of non-optimally placed actuators.

关键词： Membrane Smart structure Vibration control

Cooperative output feedback consensus control of second-order nonlinear multi-agent systems under Markovian switching topologies

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Journal of Control and Decision 2023年第4期10卷 476-483页

作者： Chuanrui Wang hua zhang Shuai zhang Shanghai Zhongchuan SDT-NERC Co. Ltd.ShanghaiPeople’s Republic of China Marine Design and Research Institute of China ShanghaiPeople’s Republic of China

This paper deals with the leader-following consensus problem for a class of second-order nonlinear multi-agent systems by output *** communication topology is characterized by a Markovian switching ***,an input-driven observer is introduced to estimate the consensus error of each follower ***,a cooperative nonlinear control law is constructed using the relative output information between neighboring agents by employing the backstepping methodology,which achievesleader-following consensusin mean square *** with the existing results,the nonlinear functions are required to satisfy polynomial growth condition rather than globally Lipschitz growth or Lipschitz-like growth condition.A numerical example is given to illustrate the theoretical results.

关键词： Multi-agent systems nonlinear systems Markovian switching topology output feedback

Transverse Bending Characteristics in U-channel Forming of Tailor Rolled Blank

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Journal of Iron and Steel Research International 2016年第12期23卷 1249-1254页

作者： hua-wei zhang Ying-ping GUAN Jia-lu WU Xiang-hua LIU School of Control Engineering Northeastern University at Qinhuangdao College of Mechanical Engineering Yanshan University Research Institute of Science and Technology Northeastern University

Research on the formability of tailor rolled blank （TRB） is of good practical significance and application value because of the enormous potential of TRB in the aspect of automobile lightweight. However, the forming of TRB is problematic because of the varying properties; especially, springback is a main challenge. The transverse bending （bending axis is perpendicular to the rolling direction） of TRB U channel was studied through simulation and experiment. The forming characteristics of TRB U channel during transverse bending were analyzed. The mechanisms of forming defects, including bending springback and thickness transition zone （TTZ） movement, were revealed. On this basis, effects of blank geometric parameters on springbaek and TTZ movement were discussed. The results indicate that springback and TTZ movement happen during transverse bending of TRB U-channel. Nonuni form stress distribution is the most fundamental reason for the occurrence of springback of TRB during transverse bending. Annealing can eliminate nonuniform stress distribution, and thus diminish springbaek of TRB, especially springback on the thinner side. Therefore, springback of the whole TRB becomes more uniform. However, annealing can increase the TTZ movement. Blank thickness and TTZ position are the main factors affecting the formability of TRB U-channel during transverse bending.

关键词： tailor rolled blank transverse bending springback U-channel annealing thickness transition zone

Algebraic dynamics solution and algebraic dynamics algorithm of Burgers equations

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Science China(Physics,Mechanics & Astronomy) 2008年第11期51卷 1647-1652页

作者： zhang hua LU WeiTao WANG ShunJin Center of Theoretical Physics Sichuan UniversityChengdu 610064China

Algebraic dynamics solution and algebraic dynamics algorithm of nonlinear partial differential evolution equations in the functional space are applied to Burgers equation. The results indicate that the approach is effective for analytical solutions to Burgers equation, and the algorithm for numerical solutions of Burgers equation is more stable, with higher precision than other existing finite difference algo-rithms.

关键词： algebraic dynamics solution in functional space algebraic dynamics algorithm for Burgers equation

Equilibrium Climate Response of the East Asian Summer Monsoon to Forcing of Anthropogenic Aerosol Species

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Journal of Meteorological Research 2017年第6期31卷 1018-1033页

作者： Zhili WANG Qiuyan WANG hua zhang State Key Laboratory of Severe Weather/Key Laboratory of Atmospheric Chemistry of China Meteorological Administration Chinese Academy of Meteorological Sciences Beijing 100081 Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044 Laboratory for Climate Studies National Climate CenterChina Meteorological AdministrationBeijing 100081

We used an online aerosol-climate model to study the equilibrium climate response of the East Asian summer monsoon （EASM） to increases in anthropogenic emissions of sulfate, organic carbon, and black carbon aerosols from 1850 to 2000. Our results show that each of these aerosol species has a different effect on the EASM as a result of changes in the local sea-land thermal contrast and atmospheric circulation. The increased emission of sulfate aerosol leads to a decrease in the thermal contrast between the land and ocean, a southward shift of the East Asian subtropical jet, and significant northerly wind anomalies at 850 hPa over eastern China and the ambient oceans, markedly dampening the EASM. An increase in organic carbon aerosol results in pronounced surface cooling and the forma- tion of an anomalous anticyclone over the oceans north of 30°N. These effects cause a slight increase in the sea-land thermal contrast and southerly flow anomalies to the west of the anticyclonic center, strengthening the northern EASM. An increase in organic carbon emission decreases the sea-land thermal contrast over southern China, which weakens the southern EASM. The response of the summer 850-hPa winds and rainfall over the East Asian monsoon region to an increase in black carbon emission is generally consistent with the response to an increase in organic carbon. The increase in black carbon emission leads to a strengthening of the northern EASM north of 35°N and a slight weakening of the southern EASM south of 35°N. The simulated response of the EASM to the increase in black carbon emission is unchanged when the emission of black carbon is scaled up by five times its year 2000 levels, although the intensities of the response is enhanced. The increase in sulfate emission primarily weakens the EASM, whereas the increases in black carbon and organic carbon emissions mitigate weakening of the northern EASM.

关键词： East Asian summer monsoon sulfate black carbon organic carbon equilibrium climate response

Stability of Functional Equations in Several Variables

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Acta Mathematica Sinica,English Series 2007年第2期23卷 321-326页

作者： Deng hua zhang huai Xin CAO College of Mathematics and Information Science Shaanxi Normal University

We prove a generalization of Hyers＇ theorem on the stability of approximately additive mapping and a generalization of Badora＇s theorem on an approximate ring homomorphism. We also obtain a more general stability theorem, which gives the stability theorems on Jordan and Lie homomorphisms. The proofs of the theorems given in this paper follow essentially the D. H. Hyers-Th. M. Rassias approach to the stability of functional equations connected with S. M. Ulam＇s problem.

关键词： stability functional equation, Jordan homomorphism, Lie homomorphism