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Metamaterials and Metamaterial-Based Antenna Technology

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上海大学学报（自然科学版） 2014年第5期20卷 531-540页

作者： chen zhi-ning Department of Electrical and Computer Engineering National University of Singapore Singapore117576 Singapore Institute for Infocomm Research Agency of Science Technology and Research Singapore 138632 Singapore

The study of metamaterials is among the most important and attractive topics of the electromagnetic field theory and applications in the past 15 *** effort has been devoted to scientific research into the new physical phenomena with great *** paper presents the thoughts about the applications of metamaterials in innovative antenna designs from an engineering *** new understanding of metamaterials offers us great possibility to translate the physical concepts of metamaterials in laboratories to innovative antenna designs in practical engineering *** technologies have been successfully developed,significantly improving key performances of antennas at microwave and millimeter-wave *** recently invented metamaterial-based antennas demonstrate not only wide operating bandwidth,high antenna efficiency,high gain,but also significantly reduced volume with simple mechanical structures.

关键词：材料科技探究声明

The construction and approximation of some neural networks operators

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Applied Mathematics(A Journal of Chinese Universities) 2012年第1期27卷 69-77页

作者： chen zhi-xiang CAO Fei-long ZHAO Jian-wei Department of Mathematics Shaoxing UniversityShaoxing 312000China Department of Mathematics China Jiliang UniversityHangzhou 310018China

In this paper, the technique of approximate partition of unity is used to construct a class of neural networks operators with sigmoidal functions. Using the modulus of continuity of function as a metric, the errors of the operators approximating continuous functions defined on a compact interval are estimated. Furthmore, Bochner-Riesz means operators of double Fourier series are used to construct networks operators for approximating bivariate functions, and the errors of approximation by the operators are estimated.

关键词： approximation sigmoidal function neural network operator Bochner-Riesz mean.

Quadrilaterals, extremal quasiconformal extensions and Hamilton sequences

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Applied Mathematics(A Journal of Chinese Universities) 2010年第2期25卷 217-226页

作者： chen zhi-guo ZHENG Xue-liang YAO Guo-wu Department of Mathematics Zhejiang University Hangzhou 310028 China Department of Mathematics Taizhou College Linhai 317000 China Department of Mathematical Sciences Tsinghua University Beijing 100084 China

The relationship between Strebel boundary dilatation of a quasisymmetric function h of the unit circle and the dilatation indicated by the change in the modules of the quadrilaterals with vertices on the circle intrigues many mathematicians. It had been a conjecture for some time that the dilatations Ko（h） and K1（h） of h are equal before Anderson and Hinkkanen disproved this by constructing concrete counterexamples. The independent work of Wu and of Yang completely characterizes the condition for Ko（h） = K1 （h） when h has no substantial boundary point. In this paper, we give a necessary and sufficient condition to determine the equality for h admitting a substantial boundary point.

关键词： Extremal quasiconformal mapping quasisymmetric mapping Hamilton sequence substantial boundary point.

Activation and afterheat analysis for CH HCSB TBM

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核聚变与等离子体物理 2006年第3期26卷 176-180页

作者： chen zhi FENG Kai-ming ZHANG Guo-shu YUAN Tao Southwestern Institute of Physics Chengdu 610041

With an activation calculation code FDKR and decay chain data library AF-DCDLIB, the radioactivity, afterheat decay and Biological Hazard Potential (BHP) from activation products have been analyzed in the CH HCSB TBM. The calculation results show that the total radioactivity inventory, heat decay and BHP are 2.10×1016Bq、5.06×10?3 MW、68.6 km3·(kW)?1, respectively, at shutdown after a continuous irradiation over 0.53 years with 500 MW fusion power. It shows that there isn’t seriously environmental safety issue in the TBM.

关键词： TBM 激化残热 BHP 热核反应

Study on the failure mechanism of Ag-Ce contacts in DC level

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第3期8卷 449-452页

作者： MENG Fan-bin LU Jian-guo LU Ning-yi chen zhi-chao chen Qi School of Materials Science and Engineering Hebei Univertity of Technology Tianjin 300130 China Hongfa Electroacoustic Co. Ltd Xiamen 361021 China

Nominal contact resistance, minimum erosion and material transfer are required with low cost materials working in a wide currents range for DC relays. Ag-Ni contact materials have low contact resistance, but the erosion and material transfer are large at high current level. Ag-SnO2 contact materials have good anti-welding properties and resistance to arc erosion, but they have large contact resistance during working and are easily block SnO2 from flocking together on the surface at low current level. In this paper, the failure mechanisms of Ag-Ce contact material were studied. The surface morphologies of the contacts after electrical endurance test for Ag-Ce contact material were compared with that of Ag-Ni and Ag-SnO2 contact materials. The effect of Ce on the surface morphologies of the contacts after electrical endurance test was analyzed.

关键词： Relays Electric contact Failure analysis

Effect of coagulation pretreatment on the fouling of ultrafiltration membrane

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Journal of Environmental Sciences 2007年第3期19卷 278-283页

作者： DONG Bing-zhi chen Yan GAO Nai-yun FAN Jin-chu State Key Laboratory of Pollution Control and Resource Reuse Tongji University Shanghai 200092 China

The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）. A relatively higher molecular weight （MW） of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.

关键词： drinking water treatment ultrafiltration coagulation fouling

Sedimentary paleoenvironment and its control on organic matter enrichment in the Mesoproterozoic hydrocarbon source rocks in the Ordos Basin,southern margin of the North China Craton

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Petroleum Science 2024年第4期21卷 2257-2272页

作者： zhi-chen Wu Ju-Ye Shi Tai-Liang Fan Ming Jiang School of Energy Resources China University of Geosciences(Beijing)Beijing100083China Key Laboratory of Marine Reservoir Evolution and Hydrocarbon Enrichment Mechanism Ministry of EducationChina University of Geosciences(Beijing)Beijing100083China

The black shale of the Mesoproterozoic Cuizhuang Formation in the Changcheng System in Yongji city,North China Craton,is a potential source *** the organic matter enrichment mechanism is crucial for evaluating source rock resources and understanding oil and gas accumulation *** this study,we evaluated the sedimentary paleoenvironment and organic matter enrichment mechanisms of shale using thin section observations,mineral composition analysis,organic geochemistry,and elemental *** found significant differences in the sedimentary paleoenvironment and organic matter enrichment mechanisms between the lower Cuizhuang Formation and the Beidajian Formation *** Cuizhuang Formation was deposited in a late-stage,restricted basin environment during the rift phase,and elemental and geochemical indicators showed that the Cuizhuang Formation was in a suboxic-anoxic water environment,that was influenced by a warm and humid paleoclimate and submarine hydrothermal activities,which promoted the accumulation of organic ***,the enrichment of organic matter in the Cuizhuang Formation was mainly controlled by redox *** formation of suboxic-anoxic water environments may be closely related to the warm and humid paleoclimate and submarine hydrothermal *** conditions promote continental weathering and increase marine productivity,thereby consuming oxygen in the bottom ***,acidic hydrothermal activity also helps to establish an anoxic *** results reveal the effects controlling various coupled mechanisms dominated by redox conditions,which may explain the development of source rocks in the Cuizhuang Formation.

关键词： Cuizhuang formation Paleoproterozoic source rocks Marine productivity Paleoenvironments Submarine hydrothermal activity Organic matter enrichment

RO-heparin Inhibits L-Selectin-mediated Neutrophils Adhesion to Vascular Endothelium Under Flow Conditions

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Chemical Research in Chinese Universities 2006年第3期22卷 302-307页

作者： chen zhi-hong XU Li BA Xue-qing ZENG Xian-lu Institute of Genetics and Cytology Northeast Normal University Changchun 130024 P. R. China School of Life Science Mudanjiang Medical University Mudanjiang 157011 P. R. China Biology Section College of Changchun Traditional Chinese Medicine Changchun 130017 P. R. China

Selectins are carbohydrate-binding cell adhesion molecules that play a major role in the initiation of inflammatory responses. Accumulaed evidence has suggested that heparin＇s anti-inflammatory effects are mainly mediated by blocking L-or P-selectin-initiated cell adhesion. Recently, we have reported that periodate-oxidized, borohydridereduced heparin （RO-heparln） can inhibit P-selectin-mediated acute inflammation. Here we further examined the effect of RO-heparin on the adhesion of L-selectin-mediated leukocytes to vascular endothelium under flow conditions in vivo and in vitro. The results show that RO-heparin with a low anticoagulant activity can effectively reduce leucocyte roiling on thioglycoUate-induced rat mesenterlc venules and L-selectin-metadiated neutrophil roiling on TNF-α-induced human umbilical vein endothelial cells（HUVECs） under flow conditions. Our findings suggest that the effect of RO-heparin on inflammatory responses is mainly a result of its inhibiting the interaction between P- or L-selectin and its ligands. The findings also suggest that RO-heparin may be useful in preventing inflammation diseases.

关键词： RO-heparin Neutrophils adhesion L-selectin Human umbilical vein endothelial cells (HUVECs)

Progress in organic photocatalysts

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Rare Metals 2018年第1期37卷 1-12页

作者： Ying-zhi chen Wen-Hao Li Ling Li Lu-Ning Wang School of Materials Science and Engineering University of Science and Technology Beijing State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing

Organic materials have advantages of diversity,ease of functionality, self-assembly, etc. The varied mechanistic pathways also make it conceivable to design an appropriate photocatalyst for an identical reaction. From this perspective, organic photocatalysts find wide applications in homogeneous, heterogeneous photocatalysis and photoelectrochemical（PEC） solar cells. In this review, the form of the employed organic photocatalysts ranging from molecules, supported molecules, to nanostructures or thinfilm aggregates will be firstly discussed. Rational design strategies relating to each form are also provided, aiming to enhance the photoenergy conversion efficiency. Finally,the ongoing directions for future improvement of organic materials in high-quality optoelectronic devices are also proposed.

关键词： Organic photocatalysts Homogeneous photocatalysis Heterogenization Organic nanostructures Photoelectrochemical water splitting