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The ε-Complexity of the Approximate Solution of Integral Equations with Isotropic Kernels

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Acta Mathematica Sinica,English Series 2002年第4期18卷 679-686页

作者： Wan MA Gen Sun FANG college of Mathematics & Information science of Wenzhou university, Wenzhou 325027, P. R. china Department of Mathematics, beijing normal university, beijing 100875, P. R. china college of Mathematics & Information science of Wenzhou university Wenzhou 325027 P. R. China Department of Mathematics Beijing Normal University Beijing 100875 P. R. China

The exact order of s-complexity is determined in L_p (2≤p≤∞) spaces for the second kind of Fredholm integral equations with kernels belonging to an isotropic Sobolev class.

关键词： Fredholm equation ε-complexity Sobolev classes

Singularity detection of the rabbit electrocardiogram:An evolutionary spectral method

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Progress in Natural science:Materials International 2009年第10期19卷 1317-1326页

作者： Xinyuan Liua,Dingwu He a,Liuqing Pei b,Suming Zhanga a School of Electronics Engineering and Computer science,Peking university,beijing 100871,china b college of Information science and Engineering,beijing normal university,beijing 100875,china [a]School of Electronics Engineering and Computer science Peking University Beijing 100871 China [b]college of Information science and Engineering Beijing Normal University Beijing 100875 China

The time-frequency characteristics of the spectral density of non-stationary signals(NSS) in the neighborhood of an instant time point can be determined using the evolutionary spectral *** experimental rabbit model involving ligation of the left anterior descending coronary artery to simulate the physiology of early phase myocardial ischemia(EPMI) has been previously ***,EPMI derived from left coronary artery stenosis is the main symptom of coronary heart diseases including acute myocardial ***,we propose a new algorithm for estimating the evolutionary spectral density functions,which is an effective approach to determine the instantaneous frequency spectra(IFS) of NSS under the uncertainty principle in the time-frequency *** localization singularity information in the data recorded from a living system could be detected by means of the ***(ECG) data recorded from experimental rabbits were analyzed with the new *** showed that the Q’s value of the evolutionary spectral quality number of the QRS-complex data was the characteristic parameter of ECG,and there was a matched connection between the time-frequency characteristics of QRS-complex data and the myocardial ischemia symptoms of the *** results provide valuable information regarding features of the EPMI for use in clinical diagnoses.

关键词： Non-stationary signals Electrocardiogram(ECG) Evolutionary spectrum Instantaneous frequency spectrum(IFS) Myocardial ischemia

Cu(Ⅱ) Potentiation of Alzheimer Aβ1-40 Cytotoxicity and Transition on its Secondary Structure

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Acta Biochimica et Biophysica Sinica 2006年第11期38卷 765-772页

作者： Xue-Ling DAI~1 Ya-Xuan SUN~2 Zhao-Feng JIANG~2* 1 college of Life science,Capital normal university,beijing 100037,china 2 college of Applied sciences and Humanities,beijing Union university,beijing 100083,china college of Life science Capital Normal UniversityBeijing 100037 China college of Applied sciences and Humanities Beijing Union UniversityBeijing 100083 China

Mounting evidence has shown that dyshomeostasis of the redox-active biometals such as Cuand Fe can lead to oxidative stress,which plays a key role in the neuropathology of Alzheimer's disease（AD）.Here we demonstrate that with the formation of Cu（Ⅱ）·Aβ1-40 complexes,copper markedly potentiatesthe neurotoxicity exhibited by β-amyloid peptide （Aβ）.A greater amount of hydrogen peroxide was releasedwhen Cu（Ⅱ）·Aβ1-40 complexes was added to the xanthine oxidase/xanthine system detected by potassiumiodide *** bound to Aβ1-40 was observed by electron paramagnetic resonance（EPR） *** dichroism （CD） studies indicated that copper chelation could cause a structuraltransition of Aβ.The addition of copper to Aβ introduced an increase on β-sheet as well as α-helix,whichmay be responsible for the aggregation of Aβ.We hypothesized that Aβ aggregation induced by copper maybe responsible for local injury in *** interaction between Cu2+and Aβ also provides a possible mechanismfor the enrichment of metal ions in amyloid plaques in the AD brain.

关键词： Alzheimer’s disease Cu(Ⅱ)·Aβ1-40 complex neuron injury Aβ secondary structure

Structural and mechanical properties of amorphous carbon films deposited by the dual plasma technique

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Journal of university of science and technology beijing 2008年第5期15卷 622-626页

作者： Yaohui Wang,Xu Zhang,Xianying Wu,Huixing Zhang,and Xiaoji Zhang Key Laboratory of the Ministry of Education of china for Beam technology and Material Modification,Institution of Low Energy Nuclear Physics,beijing normal university beijing Radiation Center,beijing 100875,china [a]Key Laboratory of the Ministry of Education of china for Beam technology Material Modification Institution of Low Energy Nuclear Physics Beijing Normal University beijing Radiation Center Beijing 100875 China

Direct current metal filtered cathodic vacuum arc （FCVA） and acetylene gas （C2H2） were wielded to synthesize Ti-containing amorphous carbon films on Si （100）. The influence of substrate bias voltage and acetylene gas on the microstructure and mechanical properties of the films were investigated. The results show that the phase of TiC in the （111） preferential crystallographic orientation exists in the film,and the main existing pattern of carbon is sp2. With increasing the acetylene flow rate,the contents of Ti and TiC phase of the film gradually reduce; however,the thickness of the film increases. When the substrate bias voltage reaches -600 V,the internal stress of the film reaches 1.6 GPa. The micro-hardness and elastic modulus of the film can reach 33.9 and 237.6 GPa,respectively,and the friction coefficient of the film is 0.25.

关键词： metal containing amorphous carbon amorphous carbon films filtered arc acetylene flow rate bias voltage structure and properties

Characteristics and origins of primary fluids and noble gases in mantle-derived minerals from the Yishu area,Shandong Province,china

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science china Earth sciences 2006年第1期49卷 77-87页

作者： MA Jinlong1,2, TAO Mingxin2,3 & YE Xianren2 1. resources and Environmental School, Lanzhou university, Lanzhou 730000, china 2. Key Laboratory of Gas Geochemistry, Institute of Geology and Geophysics, Chinese Academy of sciences, Lanzhou 730000, china 3. college of resources science & technology, beijing normal university, beijing 100875, china 1. resources and Environmental School Lanzhou University Lanzhou 730000 China 2. Key Laboratory of Gas Geochemistry Institute of Geology and Geophysics Chinese Academy of Sciences Lanzhou 730000 China 3. college of resources science & technology Beijing Normal University Beijing 100875 China

Fluids and noble gases of mantle-derived materials are important tracers forthe mantle information. Compositions of primary fluids and noble gases in mantle-derived mineralsfrom the Yishu area, Shandong Province, china, were tested by the methods of heat-bursting andheat-melting respectively. The fluids are mainly composed of CO_2, CO and H_2, which account forabout 90% of the total, and are similar to the mantle-derived rocks from other areas of easternchina; ratios of ~3He/~4He in almost all samples range from 0.82 Ra to 2.74 Ra, whereas^(40)Ar/^(36)Ar from 299.5 to 758.8. Both ranges are much lower than those of the typical oceanmantle-derived samples (such as MORB) and primarily reflect the influences of the atmosphericcomponents and the radiogenic isotopes. Ratios of C/~3He range from 27.6 x 10~9 to 1050 x 10~9,N_2/Ar from 927 to 56612, and N_2/~3He from 2.5 x 10~9 to 27 x 10~9, similar to those in westernUnited States and New Zealand which belong to the tectonic plate collision regions. The ratios fallin the intersect of mantle-crust-atmosphere in the comprehensive tracer-charts, reflecting theinfluences of the atmosphere and the crusts with organic components. Our results suggest that thecomposition of the primary fluids and the isotopic ratios of the noble gases may either reflect theevolution process of mantle-derived rocks connected with the rise and eruption of magma, or theinfluence of the ancient subduction-plate on the continental mantle of this region.

关键词： noble gases, primary fluids, mantle-derived minerals, Yishu area.

Theoretical studies on the mechanism of the thermal decarboxylation and decarbonylation of a number of α-keto-acids

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Chinese Journal of Chemistry 1995年第6期13卷 487-492页

作者： CHEN,Li-Tao CHEN,Guang-Ju FU,Xiao-YuanChemistry Department,beijing normal university,beijing 100875,china Chemistry Department Beijing Normal University Beijing 100875 China

Both processes of decarboxylation and decarbonylation of a number of acids including RCOCO2H,R=H,CH3,CH2F,CF3,CH=CH2,Ph,OH have been studied by semi-empirical MO theory AMI method to verify the reaction mechanism of each process and the effect of different substituents on *** calculated results are consistent with the experimental reports and can be summed up as follows:(1) The decarboxylation of these acids to form aldehydes and carbon dioxide is concerted and takes place through a 4-membered ring transition state in which a partial negative charge develops on the carbon of the α-carbonyl group,so that the inductive effect of some substituents is favourable for this process.(2) Their decarbonylation into carboxylic acids and carbon monoxide however is the attack of the OH on the carbon of the alkyl portion of the acid,forming a 3-membered ring transition state.(3) The activation energy of decarbonylation is lower than that of decarboxylation,since oxygen is more nucleophilic than hydrogen and also the strong OH bond need not to be broken.

关键词： Decarboxylation decarbonylation a-keto-acid

Landscape Change and its effect on the environment of Daqing City

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Progress in Natural science:Materials International 2005年第7期15卷 641-649页

作者： ZANG Shuying, ZHANG Jing and JIA Li ( college of Life and Environment science, Harbin normal university, Harbin 150080, china college of resources Environment & Tourism, Capital normal university, beijing 100037, china college of Economics and Management, Northeast Agricultural university, Harbin 150030, china) college of Life and Environment science Harbin Normal University Harbin 150080 China. college of resources Environment & Tourism Capital Normal University Beijing 100037 China. college of Economics and Management Northeast Agricultural University Harbin 150030 China

In this paper, we will study the temporal-spatial landscape change from 1978 to 2001 in Daqing City, based on the mul- ti spectral scanner (MSS) and thematic mapper (TM) images of remote sensing (RS) of 1978, 1988, 1992, 1996 and 2001. In order to explain the effects of the component change on the whole landscape, we make a statistic analysis about the transfer probability matrix of the component types of the landscape by using the ARCGIS platform through the overlay analysis of different landscape components. Based on the transfer probability matrix, we calculate the in-transfer ratio, the out-transfer ratio and the contributor ratio of the special transfer process of the main landscape components. The results illustrate that the cultivated-land, grassland, swamp, and alkaline land are the main contributors resulting in the landscape change: the out-transfer ratios of grassland and swamp are much higher than the in-transfer ones; the in-transfer ratio of alkaline land is much higher than the out-transfer one; the in-transfer ratio of the land-lot is always higher than its out-transfer with the highest rate per year, although there is a small difference among the in-transfers and the out-transfers per year. The main landscape changing processes are the salination of cultivated-land, salination or desertification of grassland, salination and degeneration of swamp. Results in this paper can provide scientific basis for investigating the landscape change mechanism of resources-based city.

关键词： landscape change environmental effect transfer probability resources-based city.

Molecular and quantum mechanical studies on the monomer recognition of a highly-regular β-helical antifreeze protein

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science china Chemistry 2004年第1期47卷 34-40页

作者： YANG Zuoyin, JIA Zongchao, LIU Ruozhuang & CHEN GuangjuDepartment of Chemistry, beijing normal university, beijing 100875, china Faculty of science, beijing university of Chemical technology, beijing 100029, china Department of Biochemistry, Queen’s university, Kingston, Ontario K7L 3N6, Canada 1. Department of Chemistry Beijing Normal University 100875 Beijing China 2. Faculty of science Beijing University of Chemical Technology 100029 Beijing China 3. Department of Biochemistry Queen? University K7L 3N6 Kingston Ontario Canada

The possible interaction models for an antifreeze protein from Tenebrio molitar (TmAFP) have been systematically studied using the methods of molecular mechanics, molecular dynamics and quantum chemistry. It is hoped that these approaches would provide insights into the nature of interaction between protein monomers through sampling a number of interaction possibilities and evaluating their interaction energies between two monomers in the course of recognition. The results derived from the molecular mechanics indicate that monomer? β-sheets would be involved in interaction area and the side chains on two p-faces can match each other at the two-dimensional level. The results from molecular mechanics and ONIOM methods show that the strongest interaction energy could be gained through the formation of H-bonds when the twoβ-sheets are involved in the interaction model. Furthermore, the calculation of DFT and analysis of van der Waals bond charge density confirm further that recognition between the two TCTs mainly depends on inter-molecular hydroxyls. Therefore, our results demonstrate that during the course of interaction the most favorable association of TmAFPs is via their β-sheets.

关键词： antifreeze protein, recognition, dynamics simulation, molecular mechanics, quantum chemistry.

Using remote sensing to research beijing wetlands dynamics

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science china(Technological sciences) 2006年第z2期49卷 97-107页

作者： ZHAO Wenji, GONG Zhaoning, GONG Huili, LI Xiaojuan, ZHANG Songmei & LI Jing Key Lab of Resource Environment and GIS of beijing, Capital normal university, beijing 100037, china Northeast Institute of Geography and Agroecology, Chinese Academy of sciences, Changchun 130012, china college of resources science and technology, beijing normal university, beijing 100875, china Capital normal Univ Key Lab Resource Environm Beijing 100037 Peoples R China Capital normal Univ GIS Beijing Beijing 100037 Peoples R China Chinese Acad Sci NE Inst Geog & Agroecol Changchun 130012 Peoples R China beijing normal Univ Coll Resources Sci & Technol Beijing 100875 Peoples R China

In beijing, where wetlands are important to municipal freshwater conservation and biodiversity retention, three different types of wetlands were identified: riverside wetlands, wetlands surrounding lakes and reservoirs, and wetlands in municipal *** sensing technology was applied in combination with field investigations to monitor and analyze the changes in these wetlands, and a combination of fusion technologies,Landsat TM/ETM+ and IKONOS imaging, was used to investigate and map them. This study indicates that not only have wetland areas been reduced by half, but also their ecological environments have been degraded because of rapid economic development and population increase. Suggestions based on this research are made to reconstruct the ecological environment of the wetlands and return them to their previous state.

关键词： beijing, wetland resource, remote sensing technology, ecological environment, dynamics.