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Structural recognition of ancient Chinese ideographic characters

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仪器仪表学报 2014年第S2期35卷 233-237页

作者： Li Ning chen dan Computer School Beijing Information Science and Technology University

Ancient Chinese characters, typically the ideographic characters on bones and bronze before Shang Dynasty(16th—11th century B.C.), are valuable culture legacy of history. However the recognition of Ancient Chinese characters has been the task of paleography experts for long. With the help of modern computer technique, everyone can expect to be able to recognize the characters and understand the ancient inscriptions. This research is aimed to help people recognize and understand those ancient Chinese characters by combining Chinese paleography theory and computer information processing technology. Based on the analysis of ancient character features, a method for structural character recognition is proposed. The important characteristics of strokes and basic components or radicals used in recognition are introduced in detail. A system was implemented based on above method to show the effectiveness of the method.

关键词： ideographic character recognition structural recognition Chinese information processing

中国竞技体育实力区域空间集聚及溢出效应分析

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体育学刊 2016年第6期23卷 14-19页

作者：陈丹华南理工大学体育学院广东广州510640

利用空间计量技术探讨中国竞技体育实力区域分布格局,发现中国竞技体育实力具有空间依赖性,且已形成两大稳定的竞技体育实力区域,即以新疆自治区为核心区域的竞技体育实力低低集聚区和以四川省为核心区域的竞技体育实力高低集聚区。通... 详细信息

利用空间计量技术探讨中国竞技体育实力区域分布格局,发现中国竞技体育实力具有空间依赖性,且已形成两大稳定的竞技体育实力区域,即以新疆自治区为核心区域的竞技体育实力低低集聚区和以四川省为核心区域的竞技体育实力高低集聚区。通过传统回归模型(OLS)、空间滞后模型(SLM)和空间误差模型(SEM)对比分析发现:中国区域竞技体育实力空间溢出效应明显,呈现出"空间剥夺"现象;"地区GDP"、"居民消费水平"、"运动员发展人数"和"教练员发展人数"4个因素对竞技体育实力区域差异具有较强的解释力度。考虑到空间溢出效应后,"运动员发展人数"和"教练员发展人数"这两个因素的边际效应有所下降。

关键词：体育社会学竞技体育实力实力区域空间集聚空间溢出效应中国

Heterogeneous reactions of sulfur dioxide on dust

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Science China Chemistry 2006年第3期49卷 273-280页

作者： GAO Yunchuan chen dan Department of Environmental Engineering Shanghai Normal University Shanghai 200234 China Department of Environmental Engineering Shanghai Normal University Shanghai 200234 China

The source of urban atmospheric particles is broad, and the major source is the building dust from urban construction. Calcium is the tagged element and Portland cement is the major com- ponent of building dust. In this study, CaO was regarded as the representative oxide of building dust, and mixtures were synthesized in terms of the major element ingredients of building dust. The het- erogeneous uptake of SO2 on CaO, mixtures, Portland cement and building dust samples was inves- tigated. In situ FTIR and X-ray photoelectron spectroscopy (XPS) were used to identify the products of the reactions. In addition, the crystal phases and the surface properties of the samples were charac- terized by XRD patterns and BET specific surface area. The results show that in the presence of oxygen, sulfur dioxide can be adsorbed to sulfite and further catalytically oxidized to sulfate on the surface of CaO, the mixtures, Portland cement and building dust. The reactivity of SO2 on the surface of dust and oxides is basically a first order. The main ingredient of building dust sample is SiO2, and the one of Portland cement is Ca3SiO5.

关键词： sulfur dioxide, heterogeneous reaction, oxides, building dust, atmospheric aerosol, in situ FTIR.

Platinum catalysts supported on Nafion functionalized carbon black for fuel cell application

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Journal of Energy Chemistry 2013年第1期22卷 87-92页

作者： Fan Luo Shijun Liao dan chen Key Laboratory for Fuel Cells of Guangdong School of Chemistry and Chemical Engineering South China University of Technology

We report a high performance supported Pt catalyst, in which a perfluorosulfonic acid （Nation） functionalized carbon black is used as support. The catalyst is characterized by infrared spectroscopy （IR）, transmission electron microscopy （TEM） and X-ray diffraction （XRD）. The TEM image shows that the active Pt component is in nanoparticles and highly dispersed on the carbon black with an average particle size of 1.9 nm. The catalyst shows improved activity towards the methanol anodic oxidation and oxygen reduction reaction （ORR）, resulting from the high dispersion of active Pt component. It leads to increases in electrochemically accessible surface areas and ion channels, as well as easier charge- transfer at polymer/electrolyte interfaces. The high platinum utilization and high performance of Pt/Nafion-C catalyst make it a promising electrocatalyst for fuel cell application.

关键词： Nation functionalized highly dispersed Pt ORR

Observations of nitrous acid and its relative humidity dependence in Shanghai

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Journal of Environmental Sciences 2006年第5期18卷 910-915页

作者： HAO Nan ZHOU Bin chen dan chen Li-min Department of Environmental Science and Engineering Fudan University Shanghai 200433 China

Nitrous acid, HNO2, is an important precursor of OH radicals in the troposphere. Measurements of HNO2 and NO2, using differential optical absorption spectroscopy （DOAS）, were performed in Shanghai, China for a period from October 22, 2004 to January 4, 2005. The mean （and median） hourly concentrations of HNO2 and NO2 during this period were 1.1 （0.7） ppb and 24 （21.4） ppb respectively. A correlation between HNO2/NO2 and PM10 mass concentrations was obtained. This correlation suggests that significant heterogeneous chemical production of HNO2 may occur through NO2 reactions on aerosol surfaces. This hypothesis was further supported by detailed analysis of selected pollution episodes in this study. At the same time, the water dependence of HNO2 formation was studied by analysis of relative humidity （RH）. It showed that the maximum HNO2/NO2 ratio was increased along with RH below 70% and inhibited at RH〉70%.

关键词： DOAS heterogeneous formation nitrous acid PM,o aerosol relative humidity

Progress and major themes of research on urban shrinkage and its eco-environmental impacts

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Journal of Geographical Sciences 2023年第5期33卷 1113-1138页

作者： chen dan FANG Chuanglin LIU Zhitao Institute of Geographic Sciences and Natural Resources Research CASBeijing100101China School of Resources and Environment University of Chinese Academy of SciencesBeijing100049China

Urban shrinkage is the process of population loss,industrial and functional decline,and eco-environmental deterioration due to various natural and human factors that occur once a city’s development reaches a certain *** is an external manifestation of positive or negative changes in an urban economy,society,culture,resource use,and *** shrinkage is a new feature of global urbanization as well as a frontier of international and Chinese *** has attracted widespread attention from academics in China and overseas,becoming an emerging trend that has spread from developed countries to underdeveloped *** on and responses to urban shrinkage have also become new tasks of China’s new urbanization *** review of the existing literature reveals that there are significant temporal and spatial differences in research by Chinese and overseas scholars on urban *** shrinkage studies have paid scant attention to interactions with the eco-environment,with analyses of urban shrinkage mechanisms and factors largely focusing on economic and social development factors;and urban shrinkage index analyses have tended not to include eco-environmental quality and environmental pollution *** key tasks for future urban shrinkage research include the following:to conduct in-depth research on the mechanisms and driving factors of urban shrinkage to reveal the essence of urban shrinkage;to discover the principles behind interactions between urban shrinkage and the eco-environment,as well as to analyze the eco-environmental effects of urban shrinkage;to construct an index system for evaluating the extent,monitoring and providing warnings of,and containing urban shrinkage;and to research urban shrinkage coping strategies under different circumstances and carry out experiments and demonstrations according to local conditions.

关键词： urban shrinkage driving mechanisms eco-environmental effects research progress major themes

Improved normalization method for ductile fracture toughness determination based on dimensionless load separation principle

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Acta Mechanica Solida Sinica 2015年第2期28卷 168-181页

作者： chen Bao Lixun Cai Kaikai Shi chen dan Yao Yao School of Mechanics and Engineering Southwest Jiaotong University

This study successfully deals with the inhomogeneous dimension problem of load separation assumption, which is the theoretical basis of the normalization method. According to the dimensionless load separation principle, the normalization method has been improved by intro- ducing a forcible blunting correction. With the improved normalization method, the J-resistance curves of five different metallic materials of CT and SEB specimens are estimated. The forcible blunting correction of initial crack size plays an important role in the J-resistance curve estima- tion, which is closely related to the strain hardening level of material. The higher level of strain hardening leads to a greater difference in JQ determined by different slopes of the blunting line. If the blunting line coefficient recommended by ASTM E1820-11 is used in the improved nor- realization method, it will lead to greater fracture resistance than that processed by the blunting line coefficient recommended by ISO 12135-2002. Therefore, the influence of the blunting line on the determination of JQ must be taken into full account in the fracture toughness assessment of metallic materials.

关键词： dimensionless load separation improved normalization method dimension inho-mogeneous J-resistance curve forcible blunting correction

Extensions of Breiman’s Theorem of Product of Dependent Random Variables with Applications to Ruin Theory

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Communications in Mathematics and Statistics 2019年第1期7卷 1-23页

作者： Yu chen dan chen Wenxue Gao Department of Statistics and Finance School of ManagementUniversity of Science and Technology of ChinaHefei 230026AnhuiPeople’s Republic of China

We consider the tail behavior of the product of two dependent random variables X andΘ.Motivated by Denisov andZwart(JAppl Probab 44:1031-1046,2007),we relax the condition of the existing α+ε th moment ofΘin Breiman’s theorem to the existingαth moment and obtain the similar result as Breiman’s theorem of the dependent product XΘ,while X andΘfollow a copula *** applications,we consider a discrete-time insurance risk model with dependent insurance and financial risks and derive the asymptotic tail behaviors for the(in)finite-time ruin probabilities.

关键词： Copula Dependent product Regular variation Ruin probabilities

Bounding the sum of powers of the Laplacian eigenvaluesof graphs

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Applied Mathematics(A Journal of Chinese Universities) 2011年第2期26卷 142-150页

作者： chen Xiao-dan QIAN Jian-guo School of Mathematical Sciences Xiamen University Xiamen 361005 Fujian P.R. China

For a non-zero real number α, let sα（G） denote the sum of the αth power of thenon-zero Laplacian eigenvalues of a graph G. In this paper, we establish a connection betweensα（G） and the first Zagreb index in which the H¨older’s inequality plays a key role. By usingthis result, we present a lot of bounds of sα（G） for a connected （molecular） graph G in terms ofits number of vertices （atoms） and edges （bonds）. We also present other two bounds for sα（G）in terms of connectivity and chromatic number respectively, which generalize those results ofZhou and Trinajsti′c for the Kirchho？ index [B Zhou, N Trinajsti′c. A note on Kirchho？ index,Chem. Phys. Lett., 2008, 455： 120-123].

关键词： Laplacian eigenvalues the first Zagreb index Kirchhoff index connectivity chromatic number.