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Synergetic effect of polydopamine particles and in-situ fabricated gold nanoparticles on charge-dependent catalytic behaviors

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Particuology 2019年第3期17卷 63-70页

作者： xia han xiaolu Chen Mengfei Yan Honglai Liu Key Laboratory for Advanced Materials and School of Chemistry & Molecular Engineering East China University of Science and Technology Shanghai 200237 China

The versatile catechol unit of polydopamine (PDA) endows this molecule with a broad ranging adhesive properties and *** prepared free-standing PDA particles by a simple self-polymerization and these particles served as both an effective reductant and scaffold for a hybrid *** raspberrylike nanocomposites featured a high density of AuNPs uniformly deposited on PDA particles (PDA@Au).This system was prepared in-situ with assistance from the active catechol and amine groups of the PDA *** quantify the effect of the PDA carriers,we studied the catalytic activity of the PDA and PDA@Au *** PDA particles showed a pronounced charge-dependent catalytic activity for reduction of cationic methylene blue,negatively-charged 4-nitrophenolate,and zwitterionic rhodamine B in the presence of borohydride,whereas PDA@AuNPs showed catalytic activity with a less pronounced charge-dependence of the catalytic efficiency of the *** PDA particles served as a redox mediator and adsorbent accelerator in degradation of the dyes owing to its unique chemical structure.

关键词： Poiydopamine Gold nanoparticle Hybrid catalyst Adsorbent Redox mediator

Calculation Model and Allocation Strategy of Network Usage Charge for Peer-to-peer and Community-based Energy Transaction Market

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Journal of Modern Power Systems and Clean Energy 2023年第1期11卷 144-155页

作者： Dong han Lei Wu Xijun Ren Shiwei xia Electrical Engineering Department University of Shanghai for Science and TechnologyShanghai 200093China State Grid Anhui Electric Power Economic Research Institute Hefei 230022China Electrical Engineering Department North China Electric Power UniversityBeijing 102206China

The emergence of prosumers in distribution systems has enabled competitive electricity markets to transition from traditional hierarchical structures to more decentralized models such as peer-to-peer(P2P)and community-based(CB)energy transaction ***,the network usage charge(NUC)that prosumers pay to the electric power utility for network services is not adjusted to suit these energy transactions,which causes a reduction in revenue streams of the *** this study,we propose an NUC calculation method for P2P and CB transactions to address holistically economic and technical issues in transactive energy markets and distribution system operations,*** on the Nash bargaining(NB)theory,we formulate an NB problem for P2P and CB transactions to solve the conflicts of interest among prosumers,where the problem is further decomposed into two convex subproblems of social welfare maximization and payment *** then build the NUC calculation model by coupling the NB model and AC optimal power flow *** also employ the Shapley value to allocate the NUC to consumers fairly for the NUC model of CB ***,numerical studies on IEEE 15-bus and 123-bus distribution systems demonstrate the effectiveness of the proposed NUC calculation method for P2P and CB transactions.

关键词： Electricity market network usage charge distribution locational marginal prices Shapley value Nash bargaining transactive energy peer-to-peer transaction community-based transaction

The EM algorithm for ML Estimators under nonlinear inequalities restrictions on the parameters

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Applied Mathematics(A Journal of Chinese Universities) 2019年第4期34卷 393-402页

作者： SHEN Qi-xia MIAO Peng LIANG yin-shuang Department of Basic Course Zhengzhou University of Science and TechnologyZhengzhou 450064China Information Engineering School of Zhengzhou Institute of Technology Zhengzhou 450044China

One of the most powerful algorithms for obtaining maximum likelihood estimates for many incomplete-data problems is the EM ***,when the parameters satisfy a set of nonlinear restrictions,It is difficult to apply the EM algorithm *** this paper,we propose an asymptotic maximum likelihood estimation procedure under a set of nonlinear inequalities restrictions on the parameters,in which the EM algorithm can be *** this kind of estimation problem is a stochastic optimization problem in the *** make use of methods in stochastic optimization to overcome the difficulty caused by nonlinearity in the given constraints.

关键词： Linear regression Maximum likelihood estimation Nonlinear constraints Asymptotic properties

Study on the model of an insurer's solvency ratio in Markov-modulated Brownian markets

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Applied Mathematics(A Journal of Chinese Universities) 2011年第1期26卷 23-28页

作者： xia Deng-feng FEI Wei-yin LIANG Yong School of Mathematics and Physics Anhui Polytechnic University Wuhu 241000 China

In this paper the insurer＇s solvency ratio model with or without jump diffusion process in the presence of financial distress cost is constructed, where an insurer＇s solvency ratio is characterized by a Markov-modulated dynamics. By Girsanov＇s theorem and the option pricing formula, the expected present value of shareholders＇ terminal payoff is provided.

关键词： Markov-modulated market jump diffusion process solvency ratio Girsanov's theorem financialdistress cost.

Effect of thermal treatment on structural change of anode electrocatalysts for direct methanol fuel cells

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Particuology 2014年第4期12卷 45-50页

作者： Mingjia han Jianhuang Zeng Jianwei xia Shijun Liao School of Chemistry and Chemical Engineering South China University of TechnologyKey Laboratory of Fuel Cell Technology of Guangdong Province

Commercially available carbon-supported Pt, PtCo and PtRu catalysts from E-TEK are heat-treated in turn at 600℃ and 800℃ each for an hour. The as-received and as-heated catalysts are used as anode catalysts for direct methanol fuel cells. Structural and surface composition changes induced by heating are analyzed by X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS）, respectively. For the Pt catalyst, heating the catalysts caused only the mass activity decrease due to particle sintering, whereas the specific activity and CO tolerance remained unchanged. The performance of the PtCo and PtRu catalysts is affected differently by heating. Heating the PtRu catalyst adversely affects its catalytic activity and its CO tolerance due to Pt depletion at the surface. In contrast, although Pt depletion also takes place for the heated PtCo catalysts, these catalysts show an even higher specific activity and approximately the same CO tolerance. The observed difference is likely due to the optimum atomic ratio difference for Ru/Pt and Co/Pt; an increased atomic ratio on the surface for Co/Pt results in an activity enhancement, which is contrary to the effect of the increase of Ru/Pt atomic ratio.

关键词： Structural changesMethanol electrooxidationCO tolerancePt depletion

An Empirical Study on Chinese City Network Pattern Based on Producer Services

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Chinese Geographical Science 2013年第3期23卷 274-285页

作者： ZHEN Feng WANG xia yin Jun ZhanG Min School of Architecture and Urban Planning Nanjing University Center of Human Geography Research Nanjing University School of Geography and Ocean Sciences Nanjing University

Globalization and informatization have accelerated city networking process over the world, which makes research on city network a hot topic in the fields of urban geography and economic geography. With Chinese economic structure adjustment and city economic growth, producer services have begun to play an increasingly important role in city-region networking. This paper employs the methodology of world city network to analyze and explain the spatial development characteristics of China's urban network system based on the data of nationwide producer services enterprise network. The research result indicated that the distribution of producer services network has a positive effect on the development of Chinese city networks. City network connectivity is closely related to the significance of city in producer services development, and the former will gradually decline with the drop of the latter. Accordingly, the 64 cities can be divided into the national central cities, regional central cities, sub-regional central cities and local central cities in accordance with their position and role in the nationwide producer services network. It is concluded that high-grade cities with quality producer services dominate the pattern of Chinese city networks and there emerges three spatial agglomerations of producer services enterprises in Changjiang (Yangtze) River Delta, Zhujiang (Pearl) River Delta and Beijing-Tianjin-Tangshan Economical Region. Moreover, the distribution of different producer services industry varies from city to city, which also affects the characteristics of network development.

关键词： world city network producer services urban hierarchy network connectivity Chinese city network

A single-cell transcriptome atlas reveals the trajectory of early cell fate transition during callus induction in Arabidopsis

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Plant Communications 2024年第8期5卷 18-31页

作者： Ruilian yin Ruiying Chen Keke xia Xun Xu College of Life Sciences University of Chinese Academy of SciencesBeijing 10049China BGI Research Beijing 102601China Guangdong Provincial Key Laboratory of Genome Read and Write BGI-ShenzhenShenzhen 518120GuangdongChina

The acquisition of pluripotent callus from somatic cells plays an important role in plant development studies and crop genetic *** developmental process incorporates a series of cell fate transitions and ***,our understanding of cell heterogeneity and mechanisms of cell fate transition during callus induction remains quite ***,we report a time-series single-cell transcriptome experiment on Arabidopsis root explants that were induced in callus induction medium for 0,1,and 4 days,and the construction of a detailed single-cell transcriptional atlas of the callus induction *** identify the cell types responsible for initiating the early callus:lateral root primordium-initiating(LRPI)-like cells and quiescent center(QC)-like ***-like cells are derived from xylem pole pericycle cells and are similar to lateral root *** delineate the developmental trajectory of the dedifferentiation of LRPI-like cells into QC-like ***-like cells are undifferentiated pluripotent acquired cells that appear in the early stages of callus formation and play a critical role in later callus development and organ *** also identify the transcription factors that regulate QC-like cells and the gene expression signatures that are related to cell fate ***,our cell-lineage transcriptome atlas for callus induction provides a distinct perspective on cell fate transitions during callus formation,significantly improving our understanding of callus formation.

关键词： callus induction single-cell RNA-seq cell fate transition developmental trajectory transcriptional regulation pluripotency

An approach to grading coalbed methane resources in China for the purpose of implementing a differential production subsidy

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Petroleum Science 2019年第2期16卷 447-457页

作者： Liangyu xia Yujie yin Xin Yu Yuhua Zheng School of Economic and Management China University of Petroleum-Beijing Information Technology Center BGP CNPC

The heterogeneity of coalbed methane(CBM) resources was not taken into account when the current indiscriminate subsidy policy was developed. In it, limited subsidy funds are given first to high-quality resources and even to subsidize profitable projects. Thus, the policy has had less than the intended effect in improving CBM production. To implement a new type of differential subsidy, it is necessary to grade the CBM resources, as will be discussed in this paper. After the factors affecting the resources value are systemically examined, sorted and merged, the relationship between the key factors and economic value is analyzed by an engineering economics method, and the production profile type, peak production(or stable production) and buried depth are used as grading factors. The production profile type is used to categorize, and peak production and buried depth are used to grade resources within the same category. The grading method is as follows: use subsidy levels at the economic critical point(NPV = 0) to identify the grades of resources, and determine the combination of peak production and buried depth for different resources grades base on indifference curves drawn according to the relationship between the economic value and peak production and buried depth.

关键词： Coalbed methane Production profile type Peak production Buried depth Differential subsidies

Ultrathin ZnO membranes a few atomic layers in thickness

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Science China(Technological Sciences) 2014年第2期57卷 315-321页

作者： yin JianBo xia HuaRong LIANG Jia ZhanG GengMin Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics Peking University Academy for Advanced Interdisciplinary Studies Peking University

For the first time we fabricated ZnO membranes with thicknesses of 2.4 nm by a facile one-pot synthesis in aqueous *** crystal analysis revealed that the hexagonal ZnO membranes were about 10 atomic layers in *** ZnO membranes bent,scrolled,intersected with each other,and self-assembled to particles in micrometre *** hierarchical assemblies showed sponge-like structures with room *** the growth process,a cationic polyelectrolyte was utilized to modulate growth behavior of the ZnO *** a result,the preferred growth direction of ZnO membranes is along 0110,which was perpendicular to[0001]growth direction in a typical hydrothermal *** growth mechanism of the membranes was also discussed.

关键词： ZnO 2D materials nanosheets hierarchical structures