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The Method of A-Harmonic Approximation and Boundary Regularity for Nonlinear Elliptic Systems under the Natural Growth Condition

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Acta Mathematica Sinica,English Series 2009年第1期25卷 133-156页

作者： Shu Hong chen Zhong tan School of Mathematical Science Xiamen University Xiamen 361005 P. R. China

We consider the questions of boundary regularity for weak solutions of second-order nonlinear elliptic systems under the natural growth condition. We obtain a general criterion for a weak solution to be regular in the neighborhood of a given boundary point. The proof yields directly the optimal regularity for the solution in this neighborhood. This result is new for the situation under the natural growth conditions.

关键词： nonlinear elliptic systems natural growth condition A-harmonic approximation technique,boundary partial regularity

Styrene-containing Phosphine-sulfonate Ligands for Nickel-and Palladium-catalyzed Ethylene Polymerization

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Chinese Journal of Polymer Science 2021年第4期39卷 447-454,I0006页

作者： Shabnam Behzadi chen Zou Bang-Pei Yang chen tan Chang-Le chen Chinese Academy of Sciences Key Laboratory of Soft Matter Chemistry Hefei National Laboratory for Physical Sciences at the MicroscaleDepartment of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationAnhui UniversityHefei230026China

A series of phosphine-sulfonate ligands bearing 2-,3-and 4-vinylphenyl on the phosphorus atom were designed,synthesized,characterized and investigated in Ni-and Pd-catalyzed ethylene *** structure of the phosphine-sulfonate Pd complex bearing 2-vinylphenyl on the phosphorus atom showed 2,1-insertion for the 2-vinyl *** phosphine-sulfonate Ni complex bearing 2-vinylphenyl resulted in significantly increased thermal stability and polyethylene molecular weights(Mn=3.69×10^(4)g·mol^(-1) at 80℃)versus the counterparts bearing 3-/4-vinyl groups as well as previously reported phosphine-sulfonate Ni complexes bearing bulky biaryl substituents.

关键词： Phosphine-sulfonate Ethylene polymerization Steric effect Palladium Nickel

Advancements in the development of liquid organic hydrogen carrier systems and their applications in the hydrogen economy

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Progress in Natural Science:Materials International 2024年第5期34卷 825-839页

作者： Alexis Munyentwali Khai chen tan Teng He Dalian Institute of Chemical Physics Chinese Academy of Sciences Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences

The transition towards sustainable and clean energy systems has become a significant concern in the modern world. Hydrogen has the potential to meet the growing energy demands while addressing greenhouse gas emissions. However, one major obstacle in utilizing hydrogen as a fuel is the lack of efficient and cost-effective storage methods. In this regard, liquid organic hydrogen carriers(LOHCs) offer several advantages, including high hydrogen storage capacity, improved safety compared to traditional storage methods, and the ability to transport hydrogen using existing liquid fuels' infrastructure. This review summarizes advancements in the development of LOHC systems for hydrogen storage, with a focus on the latest and innovative systems such as those based on dehydrogenative coupling reactions, renewable LOHCs from lignocellulosic biomass, and the development of LOHCs from plastic waste recycling. In addition to the material aspect, this contribution also discusses various applications of LOHCs in the broader context of the hydrogen economy, including a recently proposed concept of mixed gas hydrogenation of LOHCs for realizing hydrogen purification and storage in a single process step. By highlighting the main advantages and challenges of each LOHC system and providing future directions in the development of efficient LOHC systems, this review aims to contribute to an extensive understanding and advancement of LOHCs in the evolving hydrogen-based economy.

关键词： Dehydrogenation Hydrogen economy Hydrogen storage Hydrogenation Liquid organic hydrogen carriers (LOHCs)

Positional Electronic Effects in Iminopyridine-N-oxide Nickel Catalyzed Ethylene Polymerization

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Chinese Journal of Chemistry 2021年第6期39卷 1683-1689页

作者： Mingjun Chi Ao chen Wenmin Pang chen tan Changle chen CAS Key Laboratory of Soft Matter Chemistry Hefei National Laboratory for Physical Sciences at the MicroscaleDepartment of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefeiAnhui 230026China Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationAnhui UniversityHefeiAnhui 230026China

A series of dibenzhydryl-based iminopyridine-N-oxide ligands bearing a range of electron-donating or-withdrawing substituents(OMe,H;and NO_(2))and corresponding nickel pre-catalysts are prepared and *** substituents are installed at different positions on the ligand structure,including 4-position of the pyridine-N-oxide moiety(position X)and 4-position of the aniline moiety(position Y).These nickel pre-catalysts are highly active in ethylene polymerization with the addition of very little amount of aluminum cocatalysts,leading to the formation of polyethylenes with molecular weights of well above one ***-donating substituents make the catalysts sensitive to polymerization *** contrast,the catalysts bearing electron-withdrawing NO_(2) substituents show relatively steady performances at different *** importantly,we demonstrate that different substituents and different positions both play important roles in determining the properties of nickel *** provides an alternative strategy for the future design of high-performance polymerization catalyst.

关键词： Ethylene Polymerization Nickel lminopyridine-N-oxide Substituent effects

SuperFlow:A Reliable and Scalable Architecture for Large-Scale Enterprise Networks

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Chinese Journal of Electronics 2016年第6期25卷 1134-1140页

作者： HU Guangwu JIANG Yong chen Wenlong chen tan WU Jianping School of Computer Science Shenzhen Institute of Information Technology Graduate School at Shenzhen Tsinghua University Information Engineering College Capital Normal University College of Computer Science Beijing University of Technology Department of Computer Science and Technology Tsinghua University

With the increasing number of users, enterprise networks have become more and more important, but it also faced new challenges in various *** OpenF low, the promising de facto Software defined networking(SDN) scheme which can provide finegrained and flow-level control for enterprise networks, yet it still has a few undesirable designs in credibility and scalability. Inspired by OpenF low-included many excellent studies, we have proposed a reliable and scalable architecture—Super Flow for large-scale enterprise networks in this paper. It inherits the merits of OpenF low, and overcomes OpenF lows limitations by introducing some novel *** prototype experiment has proved that Super Flow possesses these features with desirable performance.

关键词： Enterprise network SuperFlow OpenFlow Source address validation improvement(SAVI) Software defined networking(SDN)

Single machine scheduling with semi-resumable machineavailability constraints

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Applied Mathematics(A Journal of Chinese Universities) 2011年第2期26卷 177-186页

作者： chen Yong ZHANG An tan Zhi-yi Department of Mathematics Zhejiang University Hangzhou 310027 China

This paper considers the semi-resumable model of single machine scheduling with anon-availability period. The machine is not available for processing during a given time interval.A job cannot be completed before the non-availability period will have to partially restartafter the machine has become available again. For the problem with objective of minimizingmakespan, the tight worst-case ratio of algorithm LPT is given, and an FPTAS is also *** the problem with objective of minimizing total weighted completion time, an approximationalgorithm with worst-case ratio smaller than 2 is presented. Two special cases of the latterproblem are also considered, and improved algorithms are given.

关键词： Scheduling Machine maintenance Approximation algorithm Worst-case analysis.

Heterogeneousα-Diimine Nickel Catalysts with Improved Catalytic Performance in Ethylene Polymerization

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Chinese Journal of Chemistry 2023年第10期41卷 1155-1162页

作者： Zhanshan Ma Mengli Xu Ningning Zhu chen tan Changle chen CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefeiAnhui 230026China Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationKey Laboratory of Environment-Friendly Polymeric Materials of Anhui ProvinceAnhui UniversityHefeiAnhui 230601China

Heterogenization can improve the thermal tolerance of olefin polymerization catalysts and result in good product morphology con-trol,which are two important parameters for industrial polyethylene *** this work,α-diimine nickel catalysts bearing-OH or-ONa anchoring groups were designed and *** anchoring groups can enable facile heterogenization of the cata-lysts on *** heterogeneous catalysts demonstrated enhanced thermal stabilities,along with high catalytic activity at 120℃(up to 5.5×10^(6)g·PE·mol·Ni^(-1)·h^(-1)).Furthermore,the heterogenization process results in the improvements of many other parame-ters,including polymer morphology control,catalytic activity(up to 1.9×10^(7)g·PE·mol·Ni^(-1)·h^(-1))and polyethylene molecular weight(Mn up to 2.3×10^(6)g·mol^(-1)).More importantly,the structure and properties of the polymer products can be controlled by catalyst structures,polymerization conditions and heterogenization to achieve good mechanical properties and elasticity.

关键词： Ethylene polymerization Mechanical properties Nickel Supported catalysts Heterogeneous catalysis Polymerization Morphology

Simulation of the T-jump triggered unfolding and thermal unfolding vibrational spectroscopy related to polypeptides conformation fluctuation

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Science China Chemistry 2017年第8期60卷 1115-1129页

作者： Xian chen Tianmin Wu Zhe-Ning chen tan Jin Wei Zhuang Yisong Zheng State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matte~ Chinese Academy of Sciences Fuzhou 350002. China

We review in this article our recent simulation works on modeling peptide T-jump and thermal unfolding Fourier transform infrared spectroscopy(FTIR) and two-dimensional infrared(2DIR) spectra. The theoretical and computational techniques used,including Markov state model(MSM), integrated tempering sampling(ITS) and nonlinear exciton propagation(NEP), are first briefly introduced. The protocols for simulating the thermal unfolding as well as T-jump unfolding are then summarized in details. The simulated spectral features, such as the intensity and ellipticity, are demonstrated to agree well with the experimental observations.

关键词： polypeptides amide vibration nonlinear response MSMs T-jump implicit solvent model ITS 2DIR folding landscape

Integrating Conjugate Gradients Into Evolutionary Algorithms for Large-Scale Continuous Multi-Objective Optimization

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IEEE/CAA Journal of Automatica Sinica 2022年第10期9卷 1801-1817页

作者： Ye Tian Haowen chen Haiping Ma Xingyi Zhang Kay chen tan Yaochu Jin the Information Materials and Intelligent Sensing Laboratory of Anhui Province Institutes of Physical Science and Information TechnologyAnhui UniversityHefei 230601China the Institute of Artificial Intelligence Hefei Comprehensive National Science CenterHefei 230601China IEEE the Key Laboratory of Intelligent Computing and Signal Processing of Ministry of Education School of Artificial IntelligenceAnhui UniversityHefei 230601China the Department of Computing The Hong Kong Polytechnic UniversityHong Kong SARChina the Faculty of Technology Bielefeld UniversityBielefeld 33619Germany

Large-scale multi-objective optimization problems(LSMOPs)pose challenges to existing optimizers since a set of well-converged and diverse solutions should be found in huge search *** evolutionary algorithms are good at solving small-scale multi-objective optimization problems,they are criticized for low efficiency in converging to the optimums of *** contrast,mathematical programming methods offer fast convergence speed on large-scale single-objective optimization problems,but they have difficulties in finding diverse solutions for ***,how to integrate evolutionary algorithms with mathematical programming methods to solve LSMOPs remains *** this paper,a hybrid algorithm is tailored for LSMOPs by coupling differential evolution and a conjugate gradient *** the one hand,conjugate gradients and differential evolution are used to update different decision variables of a set of solutions,where the former drives the solutions to quickly converge towards the Pareto front and the latter promotes the diversity of the solutions to cover the whole Pareto *** the other hand,objective decomposition strategy of evolutionary multi-objective optimization is used to differentiate the conjugate gradients of solutions,and the line search strategy of mathematical programming is used to ensure the higher quality of each offspring than its *** comparison with state-of-the-art evolutionary algorithms,mathematical programming methods,and hybrid algorithms,the proposed algorithm exhibits better convergence and diversity performance on a variety of benchmark and real-world LSMOPs.

关键词： Conjugate gradient differential evolution evolutionary computation large-scale multi-objective optimization mathematical programming