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Nickel-Catalyzed Dicarbofunctionalization of Alkenes

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Chinese Journal of Chemistry 2020年第11期38卷 1371-1394页

作者： Yun-cheng Luo chang Xu Xingang Zhang Key Laboratory of Organofluorine Chemistry Center for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of Sciences345 Lingling LuShanghai 200032China

As a straightforward strategy for rapidly increasing molecular complexity,dicarbofunctionalization of alkenes has attracted substantial interests of organic synthesis,medicine chemistry,and materials ***-catalyzed cascade dicarbofunctionalizations have been flourished in this area recently,and nickel-mediated radical pathways particularly offer new opportunities in conjunctive cross-couplings with alkyl coupling ***,we give a comprehensive review of nickel-catalyzed dicarbofunctionalization of alkenes through a historical perspective,including intermolecular three-component reactions and intramolecular cascade *** the pathways discussed in this review,the carbometallation/cross-coupling process and the radical addition/cross-coupling process are the two major pathways for the nickel-catalyzed dicarbofunctionalization of *** oxidative cyclization and 1,2-metallate shift processes are also selectively *** methods overcome the limitations associated with the reactions using noble metals in the field,providing an efficient and straightforward access to structurally diversified molecules.

关键词： nickel straight catalyzed

Effect of sintering parameters on the microstructure and thermal conductivity of diamond/Cu composites prepared by high pressure and high temperature infiltration

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international Journal of Minerals,Metallurgy and Materials 2013年第2期20卷 180-186页

作者： Hui Chen cheng-chang Jia Shang-jie Li School of Materials Science and Engineering University of Science and Technology Beijing Shenzhen Haimingrun industrial Co. Ltd.

Pure Cu composites reinforced with diamond particles were fabricated by a high pressure and high temperature （HPHT） infiltration technique. Their microstructural evolution and thermal conductivity were presented as a function of sintering parameters （temperature, pressure, and time）. The improvement in interfacial bonding strength and the maximum thermM conductivity of 750 W/（m.K） were achieved at the optimal sintering parameters of 1200℃, 6 GPa and 10 min. it is found that the thermal conductivity of the composites depends strongly on sintering pressure. When the sintering pressure is above 6 GPa, the diamond skeleton is detected, which greatly contributes to the excellent thermal conductivity.

关键词： metallic matrix composites particle reinforced composites copper diamonds infiltration microstructuralevolution thermal conductivity

Lithiation-enhanced charge transfer and sliding strength at the silicon-graphene interface:A first-principles study

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Acta Mechanica Solida Sinica 2017年第3期30卷 254-262页

作者： cheng chang Xiaoyan Li Zhiping Xu Huajian Gao Applied Mechanics Laboratory Department of Engineering Mechanics Center for Nano and Micro MechanicsCenter for Advanced Mechanics and Materials Tsinghua University School of Engineering Brown University

The application of silicon as ultrahigh capacity electrodes in lithiumion batteries has been limited by a number of mechanical degradation mechanisms including fracture, delamination and plastic ratcheting, as a result of its large volumetric change during lithiation and delithiation. Graphene coating is one feasible technique to mitigate the mechanical degradation of Si anode and improve its conductivity. in this paper, first-principles calculations are performed to study the atomic structure, charge transfer and sliding strength of the interface between lithiated silicon and graphene. Our results show that Li atoms segre- gate at the （lithiated） Si-graphene interface preferentially, donating electrons to graphene and enhancing the interfacial sliding resistance. Moreover, the interfacial cohesion and sliding strength can be further enhanced by introducing single-vacancy defects into graphene. These findings provide insights that can guide the design of stable and efficient anodes of silicon/graphene hybrids for energy storage applications.

关键词： Lithium-ion batteries Silicon anode Graphene coating interracial sliding strength First-principles calculations

Effect of heavy metals on soil microbial activity and diversity in a reclaimed mining wasteland of red soil area

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Journal of Environmental Sciences 2005年第5期17卷 832-837页

作者： LiAO Min CHEN cheng-li HUANG chang-yong College of Environmental and Resources Sciences Zhejiang University Hangzhou 310029 China

The microbial biomass, basal respiration and substrate utilization pattern in copper mining wasteland of red soil area, southern China, were investigated. The results indicated that soil microflora were obviously different compared with that of the non-mine soil. Microbial biomass and basal respiration were negatively affected by the elevated heavy metal levels. Two important microbial ecophysiological parameters, namely, the ratio of microbial biomass C（ Cmic ）/organic C（ Corg ） and metabolic quotient（qCO2 ） were closely correlated to heavy metal stress. There was a significant decrease in the Cmic/Corg ratio and an increase in the metabolic quotient with increasing metal concentration. Multivariate analysis of Biolog data for sole carbon source utilization pattern demonstrated that heavy metal pollution had a significant impact on microbial community structure and functional diversity. All the results showed that soil microbiological parameters had great potential to become the early sensitive, effective and liable indicators of the stresses or perturbations in soils of mining ecosystems.

关键词： reclaimed mining wasteland soil microorganism soil microbial diversity

integration-centric approach to system readiness assessment based on evidential reasoning

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Journal of Systems Engineering and Electronics 2012年第6期23卷 881-890页

作者： Leilei chang Mengjun Li Ben cheng Ping Zeng School of information System and Management National University of Defense Technology Changsha 410073 P. R. China

An integration-centric approach is proposed to handle inadequate information in the system readiness level （SRL） assessment using the evidential reasoning （ER） algorithm. Current SRL assessment approaches cannot be applied to handle inadequate information as the input. The ER-based approach is proposed to synthesize inadequate input information and an integration-centric perspective is applied to reduce the computational complexity. Two case studies are performed to validate the efficiency of the proposed approach. And these studies are also performed to study how the inadequate information will affect the assessment result. And the differences caused by the system＇s structure. The importance of the system＇s structure in the SRL assessment is demonstrated and the contributions made in this study are summarized as conclusions.

关键词： system readiness level (SRL) technology readinesslevel (TRL) integration readiness level (iRL) evidential reasoning(ER) integration-centric.

A transient model integrating the nanoconfinement effect and pore structure characteristics of oil transport through nanopores

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Petroleum Science 2023年第6期20卷 3461-3477页

作者： cheng Cao Bin chang Zhao Yang Chao Gao School of Mathematics and Computer Science Shaanxi University of TechnologyHanzhong723001ShaanxiChina State Key Laboratory of Continental Dynamics Department of GeologyNorthwest UniversityXi'an710069ShaanxiChina Shaanxi Polytechnic institute Sch Civil EngnXianyang712000ShaanxiChina Research institute of Shanxi Yanchang Petroleum(Group)Co.Ltd Xi'an710075ShaanxiChina

Understanding the integrated transport behavior of oil in shale nanopores is critical to efficient shale oil development. in this paper, based on the time-dependent Poiseuille flow momentum equation, we present a novel transient model to describe oil transport in unsteady and steady states. The model incorporates the effect of the critical shift density, apparent viscosity, slip length, and alkane property, as well as pore tortuosity and surface roughness. We evaluated our model through a comparison with other models, experiments, and molecular dynamics simulations. The results show that the development rates of the volume flows of C_(6)–C_(12) alkane confined in inorganic nanopores and C_(12) alkane confined in organic nanopores were faster than that of the corresponding bulk alkane. in addition, the critical drift density positively promoted the volume flow development rate in the unsteady state and negatively inhibited the mass flow rate in the steady state. This effect was clearest in pores with a smaller radius and lower-energy wall and in alkane with shorter chain lengths. Furthermore, both the nanoconfinement effect and pore structure determined whether the volume flow enhancement rate was greater than or less than 1. The rate increased or decreased with time and was controlled mainly by the nanoconfinement effect. Moreover, as the wall energy increased, the flow inhibition effect increased;as the carbon number of alkane increased, the flow promotion effect increased. The results indicate that the proposed model can accurately describe oil transport in shale nanopores.

关键词： Nanopores Transient transport Nanoconfinement effect Tortuosity Roughness Allkane properties

Extended-state-observer-based robust torsional vibration suppression for rolling mill main drive system with input saturation

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Journal of iron and Steel Research international 2023年第5期30卷 985-993页

作者： Jia-qiang Chen Shu-zong Chen chang-chun Hua cheng Jia cheng Qian institute of Electrical Engineering Yanshan UniversityQinhuangdao 066004HebeiChina National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao 066004HebeiChina

A robust torsional vibration suppression strategy is proposed for the main drive system of the rolling mill subject to uncertainties,disturbances and input *** given model information incorporated into observer design,an extended state observer that relies only on roller speed measurements is developed to estimate the system states and lumped uncertainties of the rolling mill main drive *** handle the motor torque saturation,an auxiliary signal system with the same order as the plant is *** error between the control input and plant input is taken as the input of the constructed auxiliary system,and a number of signals are generated to compensate for the effect of the motor torque ***,a robust output feedback controller is introduced to obtain better transient and steady-state performance of the rolling mill main drive system and the stability of the closed-loop system is strictly proved via Lyapunov ***,comparative simulations are performed to verify the effectiveness and superiority of the proposed control strategy.

关键词： Rolling mill Main drive system Vibration suppression Extended state observer input saturation

Augmented Lagrangian Methods for p-Harmonic Flows with the Generalized Penalization Terms and Application to image Processing

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Numerical Mathematics(Theory,Methods and Applications) 2013年第1期6卷 1-20页

作者： Huibin chang Xue-cheng Tai School of Mathematical Sciences Tianjin Normal UniversityTianjin 300387 Department of Mathematics East China Normal UniversityShanghai 200241China Department of Mathematics University of BergenJohaness Brunsgate 12Bergen 5007Norway

in this paper,we propose a generalized penalization technique and a convex constraint minimization approach for the p-harmonic flow problem following the ideas in[Kang&March,iEEE *** Process.,16(2007),2251–2261].We use fast algorithms to solve the subproblems,such as the dual projection methods,primal-dual methods and augmented Lagrangian *** a special penalization term,some special algorithms are *** experiments are given to demonstrate the performance of the proposed *** successfully show that our algorithms are effective and efficient due to two reasons:the solver for subproblem is fast in essence and there is no need to solve the subproblem accurately(even 2 inner iterations of the subproblem are enough).it is also observed that better PSNR values are produced using the new algorithms.

关键词： p-harmonic flows denoising generalized penalization terms saddle-point problem image processing augmented Lagrangian methods

Numerical investigation of alleviation of undesirable effect of inter-blade vortex with air admission for a low-head Francis turbine

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Journal of Hydrodynamics 2020年第6期32卷 1151-1164页

作者： Long-gang Sun Peng-cheng Guo Luo-chang Wu State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi’an University of TechnologyXi’an710048China

in order to compensate for the stochastic nature of the power grid due to the tremendous development and the integration of renewable energy resources and meet its other requirements,the hydraulic turbines are forced to operate more frequently under partial load conditions with singular and misaligned flows inevitably excited by the inter-blade *** paper presents numerical investigations of the unsteady characteristics of the inter-blade vortex for a low-head model Francis *** SST k-ωturbulent model is used to close the unsteady Reynolds-averaged Navier-Stokes(RANS)*** flow structure of the inter blade vortex predicted by the numerical simulation is confirmed by experimental *** is shown that the total vortex volume in the runner sees a quasi-periodical oscillation,with significant flow separations created on the suction side of the runner blade.A counter measure by using the air admission into the water from the head cover is implemented to alleviate the undesirable effect of the inter-blade *** analyses show that the development of the inter-blade vortex is significantly mitigated by the injecting air that controls and changes the spatial distribution of ***,the flow aeration with a suitable air flow rate can reduce the energy dissipation caused by the inter-blade vortex and plays a critical role in preventing the excessive amplitudes of the pressure fluctuation on the suction side of the runner *** investigation provides an insight into the flow mechanism underlying the inter-blade vortex and offers a reference to alleviate and mitigate the adverse consequences of the inter-blade vortex for the Francis turbine.

关键词： Numerical simulation inter-blade vortex air admission energy dissipation pressure fluctuation Francis turbine