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Regioselectivity Study on Propylene Polymerization Catalyzed by Neutral Salicyladiminato Pd(II) Model Complex with DFT Method

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Chinese Journal of Structural Chemistry 2005年第6期24卷 723-728页

作者： YANGZhao-Di LIUYue liuying ChemicalandEnvironmentalEngineeringCollege HarbinUniversityofScienceandTechnology Harbin150080 China SchoolofChemicalEngineeringandTechnology ChinaUniversityofMiningandTechnologyXuzhou221008China

Many attempts have been made to control the regioselectivity for olefin poly- merization by varying the structures of ligands in catalysts. The regioselectivity of propylene polymerization was investigated by replacing a nitrogen atom in the Pd(II) diimine catalyst with an oxygen atom from density functional theory method at the B3LYP/LANL2DZ level. The results show that the 1,2-insertion becomes a rival mechanism to the 2,1-insertion when the nitrogen atom is replaced by the oxygen atom leading to an asymmetric environment in the catalyst, and that the steric effect in the asymmetrical catalyst plays an important part in the polymerization. The insertion barrier from 2-O is much higher than that from 2-N. A pyramid transition state was characterized for the catalyst to convert 2-O back to 2-N through internal rotation. The propylene prefers to coordinate at the opposite side of O in the catalyst. This is the driving force for the internal rotation. The results are significant for isotactic and syndiotactic polymerization.

关键词： regioselectivity salicyladiminato-Pd(II) catalyst propylene polymerization density functional theory method (DFT)

A CHARACTERIZATION OF EMBEDDABILITY OF GRAPHS ON SURFACES

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Applied Mathematics(A Journal of Chinese Universities) 1998年第2期13卷 159-164页

作者： liuying LIUYANPEI DepartmentofMathematics NorthernJiaotongUniversityBeijing100044 RUTCOR RutgersUniversityNewBrunswickNJ08903USA

In this article the C n graphs are introduced, by which a characterization of the embeddability of a graph on either an orientable surface or a non orientable surface is provided.

关键词： Jordan curve polyhedron C-graph surface

Ionization of Atoms and the Thomas－Fermi Model for the Electric Field in Crystal Planar Channels

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Communications in Theoretical Physics 2002年第9期37卷 361-364页

作者： liuying－Tai ZHANGQi－Ren DepartmentofPhysics PekingUniversityBeijing100871China CCAST（WorldLaboratory） P.O.Box8730Beijing100080China

The electric field in the crystal planar channels is studied by the Thomas-Fermi method. The Thomas-Fermi equation and the corresponding boundary conditions are derived for the crystal planar channels. The numerical solution for the electric field in the channels between (110) planes of the single crystal silicon and the critical angles of channelling protons in them arc shown. Reasonable agreements with the experimental data are obtained. The results show that the Thomas-Fermi method for the crystal works well in this study, and a microscopic research of the channel electric field with the contribution of all atoms and the atomic ionization being taken into account is practical.

关键词： ionization of atoms Thomas-Fermi method for the crystal electric field in channels

Energy Sharing and Frequency Regulation in Energy Network via Mixed H_(2)/H_(∞) Control with Markovian Jump

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CSEE Journal of Power and Energy Systems 2021年第6期7卷 1302-1311页

作者： Haochen Hua Yuchao Qin Zicheng He liuying Li Junwei Cao the College of Energy and Electrical Engineering Hohai UniversityNanjing 211100China Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China Institute of Information Technology Fudan UniversityShanghai 200433China International Automotive Research Centre WMGUniversity of WarwickCoventryCV47ALUK

In this paper,the problem of mixed optimization for energy sharing and frequency regulation in a typical energy network scenario where energy routers(ERs)interconnected AC microgrids(MGs)is ***-time Markov chains are introduced to describe the switching paths in the power dynamics of *** that the modelling of considered energy network system could be closer to the real-world engineering *** parameter estimation techniques are integrated into the proposed method to achieve better modelling accuracy and controlling *** on the parameters of MG power dynamics,the mixed H_(2)/H_(∞) controllers are obtained via stochastic control *** feasibility and efficacy of the proposed approach are evaluated in numerical examples.

关键词： Energy network microgrids H_(2)/H_(∞)control markov jump

Residue Theorem based soft sliding mode control for wind power generation systems

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Protection and Control of Modern Power Systems 2018年第1期3卷 256-267页

作者： Mohammed Alsumiri liuying Li Lin Jiang Wenhu Tang University of Liverpool LiverpoolUK

This paper proposes a residue theorem based soft sliding mode control strategy for a permanent magnet synchronous generator(PMSG)based wind power generation system(WPGS),to achieve the maximum energy conversion and improved in the system dynamic *** main idea is to set a soft dynamic boundary for the controlled variables around a reference *** the controlled variables would lie on a point inside the *** convergence of the operating point is ensured by following the Forward Euler *** proposed control has been verified via simulation and experiments,compared with conventional sliding mode control(SMC)and proportional integral(PI)control.

关键词： Maximum power point tracking Sliding mode control Residue theorem Wind power generation system Permanent magnet synchronous generator

DBU-Promoted Trifluoromethylation of Aryl Iodides with Difluoromethyltriphenylphosphonium Bromide

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Chinese Journal of Chemistry 2016年第5期34卷 481-484页

作者： Yun Wei liuying Yu Jinhong Lin Xing Zheng Jichang Xiao Institute of Pharmacy and Pharmacology University of South China 28 Western Changsheng Road Hengyang Hunan 421001 China Key Laboratory of Organofluorine Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study Institute of Pharmacy and Pharmacology University of South China 28 Western Changsheng Road Hengyang Hunan 421001 China

DBU-promoted trifluoromethylation of aryl iodides with difluoromethyltriphenylphosphonium bromide （DFPB） in the presence of copper source is described. In this transformation, DBU not only acts as base to deprotonate the difluoromethyl group in DFPB to generate difluoromethylene phosphonium ylide Ph3P＋CF2 , but also converts the difluorocarbene generated from ylide Ph3P＋CF2- into trifiuoromethyl anion, finally resulting in the trifluoromethy- lation of aryl iodides. The reactions proceeded smoothly to afford expected products in moderate to good yields.

关键词： difluorocarbene trifluoromethylation difluoromethyltriphenylphosphonium bromide copper

Are public‒private partnerships still an answer for social infrastructure?A systematic literature review

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Frontiers of Engineering Management 2023年第3期10卷 467-482页

作者： Liang MA Yangyang HU liuying ZHU Yongjian KE School of Management Shanghai UniversityShanghai 200444China Institute of Regional and Urban Development of Shanghai University Shanghai 200444China School of Built Environment University of Technology SydneySydney 2007Australia

Social infrastructure has become an important element for measuring national economic development and social benefits that are usually financed in the form of government grants,private investment,and public‒private partnerships(PPPs).However,social infrastructure PPPs have attracted considerable public debate due to their low profitability and complex operational *** study aims to answer the question,“are PPPs still an answer for social infrastructure?”,from the perspectives of the body of knowledge,application status,and ***,an iterative search and review procedure and a scientometric analysis were performed to systematically screen the literature and to structure the body of knowledge of the social infrastructure PPPs ***,the application status and trends were analyzed to further explore the studied countries/regions,application sectors,and research *** show that PPPs still have valuable application potential for delivering social infrastructure despite their mixed results across different *** main research themes and the corresponding research trends were also identified,namely,financing and economics viability,risk management,performance management,contract and relationship management,governance and regulation,and facilitating and hindering *** findings offer practitioners and researchers a comprehensive overview and constructive guidance on social infrastructure PPPs.

关键词： public‒private partnerships social infrastructure scientometric analysis systematic review

Combined immunity of DNA vector and recombinant vaccinia virus expressing Gag proteins of equine infectious anemia virus

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Chinese Science Bulletin 2004年第21期49卷 2272-2276页

作者： DAIChunming ZHANGXiaoyan WANGShuhui liuying DUANDanli SHEN-Rongxian SHAOYiming DivisionofResearchonVirologyandImmunology NationalCenterforAIDS/STDControlandPreventionCDCBeijing100050China DivisionofResearchonEIAV HarbinVeterinaryResearchInstituteHarbin150001China

In order to develop a new vaccine candidate for equine infectious anemia virus (EIAV), gag gene of Chinese donkey leukocyte attenuated strain (EIAV DLV) and its pa- rental virulent strain (EIAV LN) were inserted respectively into the TK region of the Tiantan strain (VV) of vaccinia virus by homologous recombination and the positive clone was confirmed by blue plaque assay. Protein expression was examined by Western blot. Prime and prime-boost proce- dures were used to immunize mice with two DNA vectors and two recombinant vaccinia viruses expressing EIAV Gag pro- teins. The results showed that the specific lysis of CTL re- sponses in the DNA+rVV groups was stronger than those in the DNA groups, amounting to 31%. Although the levels of specific antibodies were not significantly different, we could conclude that the recombinant vaccinia virus could boost the cellular responses following DNA vector priming. There was no detectable difference between the immune responses in- duced by DLV and LN Gag proteins. This data demonstrates that the combined immunity of DNA vector and recombinant vaccinia virus expressing EIAV gag proteins, utilizing the prime-boost procedure, can drive immunized mice to pro- duce powerful cellular responses. These results lay an im- portant foundation for the development of a new EIAV ge- netic engineering vaccine.

关键词： DNA VV LN CTL

Synergistic Effect and Electrochromic Mechanism of Nanoflake Li-doped NiO in LiOH Electrolyte

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Energy & Environmental Materials 2023年第3期6卷 66-73页

作者： Kejun Xu liuying Wang Gu Liu Chaoqun Ge Long Wang Weichao Wang Mengzhou Chen Xi’an Research Institute of High Technology Xi’an 710025China

Inorganic metal oxide electrochromic materials have good application prospects for energy-saving windows in buildings and smart display ***,the development of electrochromic films with good cycling stabilities,fast color-change response times,and high coloring efficiencies has attracted considerable *** this study,nanoflake Li-doped NiO electrochromic films were prepared using a hydrothermal method,and the films exhibited superior electrochromic performances in the LiOH ***^(+)ions doping increased the ion transmission rates of the NiO films,and effectively promoted the transportation of ions from the electrolyte into NiO ***,the nanoflake microstructure caused the NiO films to have larger specific surface areas,providing more active sites for electrochemical *** was determined that the NiO-Li20%film exhibited an ultra-fast response in the LiOH electrolyte(coloring and bleaching times reached 3 and 1.5 s,respectively).Additionally,the coloration efficiency was 62.1 cm^(2)C^(−1),and good cycling stability was maintained beyond 1500 ***,the simulation calculation results showed that Li doping weakened the adsorption strengths of the NiO films to OH^(−),which reduced the generation and decomposition of NiOOH and helped to improve the cycling stabilities of the ***,the research presented in this article provides a strategy for designing electrochromic materials in the future.

关键词： electrochromic materials Li-doped NiO films LiOH electrolyte nanoflake