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Theoretical study of bifurcated bent blue-shifted hydrogen bonds CH_2…Y

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Science china Chemistry 2008年第7期51卷 623-631页

作者： LI AnYong school of Chemistry and Chemical Engineering, southwest university, chongqing 400715, china school of Chemistry and Chemical Engineering Southwest University Chongqing China

Ab initio quantum chemistry methods were applied to study the bifurcated bent hydrogen bonds Y… H2CZ (Z = O, S, Se) and Y…H2CZ2 (Z = F, Cl, Br) (Y = Cl-, Br-) at the MP2/6-311++G(d,p) and MP2/6-311++G(2df,2p) levels. The results show that in each complex there are two equivalent blue-shifted H-bonds Y…H—C, and that the interaction energies and blue shifts are large, the energy of each Y…H—C H-bond is 15-27 kJ/mol, and Δr(CH) = -0.1 - -0.5 pm and Δv(CH) = 30 - 80 cm-1. The natural bond orbital analysis shows that these blue-shifted H-bonds are caused by three factors: large rehybridization; small direct intermolecular hyperconjugation and larger indirect intermolecular hy- perconjugation; large decrease of intramolecular hyperconjugation. The topological analysis of elec- tron density shows that in each complex there are three intermolecular critical points: there is one bond critical point between the acceptor atom Y and each hydrogen, and there is a ring critical point inside the tetragon YHCH, so these interactions are exactly H-bonding.

关键词： bifurcated bent H-bonds blue-shifted H-bonds topological property of electron density intramolecular hyperconjugation

Size effect of fullerene cages and encaged clusters in M3N@C2n

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Science china Chemistry 2009年第5期52卷 584-589页

作者： GAN LiHua school of Chemistry and Chemical Engineering, southwest university, chongqing 400715, china school of Chemistry and Chemical Engineering Southwest University Chongqing China

Based on the calculated findings that the sizes of encaged clusters determine the structures and the stability of C80-based trimetallic nitride fullerenes (TNFs), more extensive density functional theory calculations were performed on M3N@C68, M3N@C78 and M3N@C80 (M=Sc, Y and La). The calculated results demonstrated that the structures and stability undergo a transition with the increasing of the sizes of the cages and clusters. Sc3N is planar inside the three considered cages, Y3N is slightly pyramidal inside C68-6140 and C78-5 and planar inside I h C80-7, however, La3N is pyramidal inside all the three cages. Those cages with pyramidal clusters inside deformed considerably, compared with their parent cages. In these cases, the bonding of metallic atoms toward the cages does not play an impor-tant role, and the encaged cluster tends to be located inside the cages with the largest M-M and M-C distances so that the strain energy can be released mostly. These calculations revealed the size effect of fullerene cages and encaged clusters, and can explain the position priority of M3N inside fullerene cages and the differences in yield of M3N@C2n.

关键词： trimetallic nitride fullerenes (TNFs) density functional theory (DFT) size effect stability

How to Protect the Karst Aquifers?

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地学前缘 2009年第S1期16卷 32-33页

作者： Junbing Pu,Daoxian Yuan,Yongjun Jiang school of geographical sciences,southwest university,chongqing 400715,china.

The karst aquifers are the most important water resources in southwest china,where displays the most continuous bare karst around the world and hold about 100 million *** the rapid expansion of the urbanization,development of the industry and agriculture,the groundwater quality has been *** of the karst groundwater increases because of development of intensive *** of nitrate and sulphate increase notably as a result of the large amount of chemical fertilizer used in *** gas, waste water and waste residues produced in the processes of industrialization and urbanization cause groundwater acidification and an increase of pollutants such as nitrogen,phosphate,chloride,

关键词： karst aquifers groundwater quality -contamination protection measures

Construction and cross-correlation analysis of the affective physiological response database

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Science china(Information sciences) 2010年第9期53卷 1774-1784页

作者： WEN WanHui1,QIU YuHui2,LIU GuangYuan1*,CHENG NanPu3 & HUANG XiTing4 1school of Electronic and Information Engineering,southwest university,chongqing 400715,china 2College of Computer and Information Science,southwest university,chongqing 400715,china 3school of Materials Science and Engineering,southwest university,chongqing 400715,china 4school of Psychology,southwest university,chongqing 400715,china school of Electronic and Information Engineering Southwest University College of Computer and Information Science Southwest University

Six kinds of emotions,namely joy,surprise,disgust,grief,anger and fear,are elicited from 300 ordinary college students by means of high-rated movie *** signals of galvanic skin response(GSR),heart rate(HR),blood volume pulse(BVP),electrocardiogram(ECG),respiration(Rsp.),facial electromyography(EMG) and two channels of electroencephalography(EEG) from the frontal lobe were recorded while the subjects were watching the affective eliciting *** samples of each kind of signals are analyzed by using random matrix theory(RMT).From the distribution of the eigenvalues and eigenvectors of the correlation matrices of BVP,facial EMG and two EEGs,we find that the statistical properties of these four kinds of signals coincide with the RMT ***,the largest eigenvalue and the corresponding eigenvector component distribution of the correlation matrices of GSR,HR,ECG and *** deviated significantly from the RMT *** experiments also reveal that the correlations between two arbitrary samples of BVP,facial EMG or EEGs does not result from affective response but from random noises,whereas the amplitude variations of GSR,HR,ECG and *** the correlated affective physiological response *** to the data analysis results of RMT,110 features are firstly extracted from the GSR and HR signals,and then a subset of the initial features is selected by using the Backward Selection *** affective data samples each of which is a vector of the features are classified by using a Fisher classifier,and furthermore,the user-independent emotion recognition systems with good prediction performance are constructed during the model selection process.

关键词： affective computing emotion recognition affective physiological response database correlation analysis random matrix theory

An isoperimetric deficit upper bound of the convex domain in a surface of constant curvature

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Science china Mathematics 2010年第8期53卷 1941-1946页

作者： LI Ming & ZHOU JiaZu school of Mathematics and Statistics,southwest university,chongqing 400715,china school of Mathematics and Statistics Southwest University

In this paper,we give a reverse analog of the Bonnesen-style inequality of a convex domain in the surface X of constant curvature,that is,an isoperimetric deficit upper bound of the convex domain in *** result is an a... 详细信息

关键词： Kinematic formula the surface of constant curvature isoperimetric deficit convex set

The resonance Rayleigh scattering of the interaction of copper(Ⅱ)-bleomycinA2 with DNA and its analytical application

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Science china Chemistry 2010年第3期53卷 618-624页

作者： LIU JiangTao1,LIU ShaoPu2 & LIU ZhongFang2 1school of Chemistry,chongqing Normal university,chongqing 400300,china 2school of Chemistry and Chemical Engineering,southwest university,chongqing 400715,china school of Chemistry Chongqing Normal University Chongqing China school of Chemistry and Chemical Engineering Southwest University Chongqing China

The forming of bleomycinA2-Cu(Ⅱ) cationic chelate and the interaction of the chelate with DNA have been investigated by using resonance Rayleigh scattering(RRS),molecular absorption and fluorescence *** result shows that in aqueous solution,bleomycinA2(BLMA2) can react with Cu(Ⅱ) to form 1:1 cationic chelate which contributes to the changes of the absorption spectra and the quenched fluorescence of *** the cationic chelate further bound with DNA to form ternary ion-association complexes,the remarkable enhancement of the RRS intensity was *** this work,the optimum conditions for the coordination reaction of BLMA2 with Cu(Ⅱ) and some influencing factors have been *** reaction mechanism of BLMA2-Cu(Ⅱ) binding with DNA was suggested and a binding model was *** addition,the fluorescence quenching type of BLMA2 was investigated.A highly sensitive,simple and rapid new method for the determination of DNA by using BLMA2-Cu(Ⅱ) as RRS probe has been *** detection limits(3σ) are 7.2 ng/mL for ctDNA,7.1 ng/mL for sDNA and 18 ng/mL for *** method can be applied to the determination of trace amounts of DNA.

关键词： bleomycinA2 Cu(Ⅱ) DNA resonance Rayleigh scattering fluorescence quenching

Nitrogen content features of several indigenous evergreen and decidous tree species in chongqing region

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西南师范大学学报(自然科学版) 1999年第5期24卷 586-593页

作者： Zeng\ Bo school of Life Science,southwest china Normal university,chongqing 400715 西南师范大学重庆

To aid to reveal the basic physiological differences existing between evergreen and deciduous plants, so as to facilitate our understanding of relationships between physiological features of evergreen & deciduous plants and their corresponding growth and biomass production, nitrogen content patterns of four indigenous tree species in chongqing region including evergreen and deciduous plants growing in optimal conditions were analyzed. It is shown that leaf nitrogen content of deciduous tree species was significantly higher than that of evergreen tree species. Based on this result, it can be inferred that researched evergreen and deciduous tree species had basic differences in their leaf nitrogen content. There were no significant differences appeared between studied evergreen and deciduous tree species on nitrogen content of branches and stems. Compared with branch and stem, leaves had highest nitrogen content unexceptionally for all researched plants regardless of species. Nitrogen content of stems decreased with the age of stem for all investigated evergreen and deciduous species.

关键词： evergreen deciduous tree species nitrogen content chongqing

Memristive crossbar array with applications in image processing

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Science china(Information sciences) 2012年第2期55卷 461-472页

作者： HU XiaoFang,DUAN ShuKai,WANG LiDan & LIAO XiaoFeng school of Electronics and Information Engineering,southwest university,chongqing 400715,china school of Electronics and Information Engineering Southwest University

A memristor is a kind of nonlinear resistor with memory *** resistance changes with the amount of charge or flux passing through *** the fourth fundamental circuit element,it has huge potential applications in many fields,and has been expected to drive a revolution in circuit *** numerical simulations and circuitry modeling,the basic theory and properties of memristors are analyzed,and a memristor-based crossbar array is then *** array can realize storage and output for binary,grayscale and color images.A series of computer simulations demonstrates the effectiveness of the proposed *** to the advantage of the memristive crossbar array in parallel information processing,the proposed method is expected to be used in high-speed image processing.

关键词： memristor crossbar array modeling and simulation image storage image output

The Willmore functional and the containment problem in R^4

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Science china Mathematics 2007年第3期50卷 325-333页

作者： Jia-zu ZHOU school of Mathematics and Statistics, southwest university, chongqing 400715, china Department of Mathematics, Polytechnic university, Brooklyn, NY 11201, USA school of Mathematics and Statistics Southwest University Chongqing China Department of Mathematics Polytechnic University Brooklyn USA

Let∑be a convex hypersurface in the Euclidean space R4 with mean curvature H. We obtain a geometric lower bound for the Willmore functional∫∑H2dσ. This bound is an invariant involving the area of∑, the volume and Minkowski quermassintegrals of the convex body that∑bounds. We also obtain a sufficient condition for a convex body to contain another in the Euclidean space R4.

关键词： mean curvature scalar curvature kinematic formula Minkowski quermassintegrals convex body convex hypersurface 52A22 53C65 51C16