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Nano Research 2009年第12期2卷 966-974页

作者： Daesoo Kim Paresh Shimpi pu-xian Gao Department of Chemical Materials and Biomolecular Engineering&Institute of Material ScienceUniversity of ConnecticutStorrsCT 06269-3136USA

Large scale zigzag zinc blende single crystal ZnS nanowires have been successfully synthesized during a vapor phase growth process together with a small yield of straight wurtzite single crystal ZnS *** alloy nanoparticles were utilized to catalyze a vapor-solid-solid growth process of both types of ZnS nanowires,instead of the more common vapor-liquid-solid growth ***,the vapor-phase grown zigzag zinc blende ZnS nanowires are metastable under high-energy electron irradiation in a transmission electron microscope,with straight wurtzite nanowires being much more *** exposure to electron irradiation,a wurtzite ZnO nanoparticle layer formed on the zigzag zinc blende ZnS nanowire surface with concomitant displacement *** electron inelastic scattering and surface oxidation as a result of electron-beam heating occur during this structure evolution *** prolonged higher-voltage electron irradiation was applied,local zinc blende ZnS nanowire bodies evolved into ZnS-ZnO nanocables,and dispersed ZnS-ZnO nanoparticle *** AuPd nanoparticles were observed distributed on zigzag ZnS nanowire surfaces,which might be responsible for a catalytic oxidation effect and speed up the surface oxidation-induced structure evolution.

关键词： ZnS nanowire polymorph vapor-solid-solid growth transmission electron microscopy electron irradiation structure evolution

Is the “One Province One Rate” premium policy reasonable for Chinese crop insurance? The case in Jilin Province

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Journal of Integrative Agriculture 2018年第8期17卷 1900-1911页

作者： ZHOU xian-hua LIAO pu WANG Ke China Institute for Actuarial Science Central University of Finance and Economics Agricultural Information Institute Chinese Academy of Agricultural Sciences

Crop insurance in China is currently adopting the premium pricing strategy of "One Province One Rate", which appears to be in line with the systematic risk characteristics within crop insurance. This research aims to investigate the theoretical rationalization of this pricing strategy and its implications using the spatial lag model and the county-level data from the 45 corn plant counties of Jilin Province, China. Results corroborate that:(1) the spatial spillover effect of the corn yield risk is significant in Jilin but decreases rapidly when the risk unit includes more than eight counties; and(2) separating Jilin Province into eight risk zones for corn insurance will significantly reduce the high cross-subsidy phenomenon arising from the "One Province One Rate" strategy and shall benefit poor peasants in the region as well. This paper not only proves the existence of a systematic risk of crop insurance but also reveals that the spatial correlation and systemic features of the crop yield risk do not create a solid foundation for the current pricing strategy of "One Province One Rate". These conclusions will undoubtedly provide important references and empirical evidence for the role of China’s crop insurance in poverty alleviation.

关键词： crop insurance premium spatial correlation spatial lag model

On spectral theory of the Riemann zeta function

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Science China Mathematics 2019年第11期62卷 2317-2330页

作者： xian-jin Li Department of Mathematics Brigham Young University

Every nontrivial zero of the Riemann zeta function is associated as eigenvalue with an eigenfunction of the fundamental differential operator on a Hilbert-P′olya space. It has geometric multiplicity one. A relation between nontrivial zeros of the zeta function and eigenvalues of the convolution operator is given. It is an analogue of the Selberg transform in Selberg’s trace formula. Elements of the Hilbert-P′olya space are characterized by the Poisson summation formula.

关键词： Hilbert-Pólya space spectrum of operators zeros of zeta function

On Weil's explicit formula

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Science China Mathematics 2015年第5期58卷 915-982页

作者： LI xian-jin Department of Mathematics Brigham Young University

A program of proving the Riemann hypothesis by using the Fourier analysis on global fields is given by Connes(1999). The difficulty for realizing the program lies in proving the validity of Connes' global trace formula on an L2-space. In this paper, a new global trace formula is obtained on a Fr′echet space which gives the Weil distribution △(h).

关键词： global trace formula nuclear locally convex space Riemann hypothesis

A Hilbert-Schmidt integral operator and the Weil distribution

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Science China Mathematics 2023年第1期66卷 91-114页

作者： xian-jin Li Department of Mathematics Brigham Young UniversityProvoUT 84602USA

In this paper,a positive operator is *** is shown that the product of this positive operator and the convolution operator is a trace class Hilbert-Schmidt integral operator and has nonnegative eigenvalues.A formula is given for the trace of this product *** seems that this product operator is the closest trace class integral operator which has nonnegative eigenvalues and is related to the Weil distribution in the context of Connes’program for the Riemann hypothesis.A relation is given between the trace of the product operator and the Weil distribution.

关键词： eigenvalue explicit formula positivity trace of the operator

Checkerboard Colourable Twuals

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Acta Mathematica Sinica,English Series 2022年第3期38卷 612-622页

作者： Qi YAN xian An jin School of Mathematics China University of Mining and TechnologyXuzhou221116P.R.China School of Mathematical Sciences Xiamen UniversityXiamen361005P.R.China

In this article we show that any embedded graph has a checkerboard colourable twual,which is equivalent to having a bipartite *** also obtain that any Eulerian embedded graph has a checkerboard colourable partial Petr... 详细信息

关键词： Embedded graphs twuals twisted dual partial duality petrie dual medial graphs direction checkerboard colourable

Eulerian and Bipartite Binary Delta-matroids

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Acta Mathematicae Applicatae Sinica 2022年第4期38卷 813-821页

作者： Qi YAN xian-an jin School of Mathematics China University of Mining and TechnologyXuzhou 221116China School of Mathematical Sciences Xiamen UniversityXiamen 361005China

Delta-matroid theory is often thought of as a generalization of topological graph *** is well-known that an orientable embedded graph is bipartite if and only if its Petrie dual is *** this paper,we first introduce the concepts of Eulerian and bipartite delta-matroids and then extend the result from embedded graphs to arbitrary binary *** dual of any bipartite embedded graph is *** also extend the result from embedded graphs to the class of delta-matroids that arise as twists of binary *** related results are also obtained.

关键词： matroid delta-matroid binary bipartite Eulerian

Monoclinicβ-AgVO_(3) coupled with CdS formed a 1D/1D p-n heterojunction for efficient photocatalytic hydrogen evolution

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Rare Metals 2023年第5期42卷 1494-1507页

作者： Xuan-pu Wang Zhi-Liang jin Xin Li School of Chemistry and Chemical Engineering North Minzu UniversityYinchuan750021China Institute of Biomass Engineering Key Laboratory of Energy Plants Resource and UtilizationMinistry of Agriculture and Rural AffairsSouth China Agricultural UniversityGuangzhou510642China

Improving the separation of photogenerated carriers and suppressing the rapid complication of electron-hole pairs are essential ways to improve photocatalytic hydrogen production *** high recombination rate of the photogenerated carriers is an issue encountered when developing CdS as a promising photocatalytic *** work allowed to accelerate the separation of photogenerated electrons and holes by loading monoclinicβ-AgVO_(3)on hexagonal CdS nanorods to construct a one-dimensional(1D)/1D p-n *** introduction of monoclinicβ-AgVO_(3)with a narrow band gap effectively improves the light absorption of CdS,which is conducive to improving the use of visible *** integrated electric field of the p-n heterojunction can effectively transfer electrons and holes in the direction suitable to hydrogen *** photoluminescence and electrochemical characterization of the catalysts showed that the p-n heterojunction formed after loadingβ-AgVO_(3)greatly improved the separation efficiency of *** hydrogen evolution experiments show that the composite catalyst has good photocatalytic hydrogen evolution capability and *** composite catalyst with the best photocatalytic performance was obtained by studyingβ-AgVO_(3)with different *** composite catalyst reached 581.5μmol of hydrogen amount within 5 h,which is 3.8 times higher than that of CdS alone and its apparent quantum efficiency reaches8.02%.The present work provides a possible solution for the development of perovskite and the extensiveness of CdS in photocatalytic hydrogen evolution.

关键词： Photocatalysis Hydrogen evolution p-n heterojunction AgVO_(3)

Expression and hypermethylation of p27^(kip1) in hepatocarcinogenesis

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World Journal of Gastroenterology 2005年第29期11卷 4587-4591页

作者： pu-Ping Lei Zong-Ji Zhang Li-Juan Shen jin-Yun Li Qiong Zou Hua-xian Zhang Department of Pathology Kunming Medical College Kunming 650031 Yunnan Province China Department of Pathology the Second Affiliated Hospital Kunming Medical College Kunming 650032 Yunnan Province China

AIM： To study the expressions of p27^kip1 protein and p27mRNA, the hypermethylation of p27^kip1 and the relation between them in various stages of hepatocarcinogenesis. METHODS： p27 protein and p27mRNA were detected by immunohistochemical staining and in situ hybridization respectively in 68 cases of normal liver, liver cirrhosis, pericancerous cirrhosis and hepatocellular carcinoma （HCC）. The hypermethylation of p27^kip1 was detected by methylation-specific PCR （MSP） in 44 cases of normal liver, liver cirrhosis, and HCC. RESULTS： The positive rate of p27 protein was 66.7% （4/6） in normal liver, 60.0% （6/10） in liver cirrhosis, 50.0% （12/24） in pericancerous cirrhosis and 21.4% （6/28） in HCC. There were no statistical differences in normal liver, liver cirrhosis and pericancerous cirrhosis, but the positive rate of p27 protein significantly decreased in HCC compared to that in the other groups （P = 0.006, %2 = 7.664）. The positive rate of p27^kip1 mRNA was 83.3% （5/6） in normal liver, 70.0% （7/10） in liver cirrhosis, 75.0% （18/24） in pericancerous cirrhosis and 25.0% （7/28） in HCC. There were no statistical differences in normal liver, liver cirrhosis and pericancerous cirrhosis, but the positive rate of p27^kip1 mRNA also significantly decreased in HCC compared to that in the other groups （P = 0.000, %2 = 16.600）. In addition, there was a significant correlation between the expression of p27 protein and p27mRNA in the integrated group of normal liver and liver cirrhosis. However, no significant correlation was found between pericancerous cirrhosis and HCC. Using MSP, we found that 1 HCC in 44 cases （including 6 cases of normal liver, 10 cases of liver cirrhosis and 28 cases of HCC） was methylated, whose p27 protein and p27mRNA were negative. CONCLUSION： The reduction or loss of p27 protein and p27mRNA are potentially involved in hepatocarcinogenesis. The hypermethylation of p27 might lead to the loss of p27mRNA transcription.

关键词： Hepatocellular carcinoma p27^kip1 Immunohistochemical staining In situ hybridization Hypermethylation

Renewed investigation on Power System Stabilizer design

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Science China(Technological Sciences) 2011年第10期54卷 2687-2693页

作者： MA jin WANG Haojing ZHANG pu School of Electrical and Electronic Engineering North China Electric Power University Beijing 102206 China Beijing Power Company Beijing 100031 China

Power System Stabilizer (PSS) was proposed during 1960s to solve the low frequency oscillation problem raised by the wide application of the high-gain fast-response exciters. The fundamentals of PSS design lie in the angle compensation to increase the damping torque, which, since then, has become an important principle in designing the various power system dampers, such as SVC, TCSC, UPFC. Although many papers have been dedicated to the application of this principle, it is interesting to note that in the real industry applications PSS parameters have to be carefully tuned on site in spite of its mature design theory. So does the classical PSS design theory really meet the PSS design demand? By combining the frequency domain and the time domain analysis, this paper reinvestigates the basic idea behind the classical PSS design theory. The paper clarifies the con-cepts of the synchronous torque as well as the damping torque and proves that the classical PSS design principles based on these concepts are not theoretically sound. Then the paper discusses the Linear Optimal Controller Design method and ana-lyzes its relations with the conventional PID design. By doing so the paper reveals the real mechanism of the PSS and proposes to use more systematic and advanced control tools to enhance the controller performance.

关键词： power system stabilizer low frequency oscillation power system dynamics