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On the Index of Fredholm Pairs of Idempotents

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Acta Mathematica Sinica,English Series 2009年第4期25卷 679-686页

作者： Yue Qing WANG Hong Ke DU Yan Ni DOU Department of mathematics and {1. Chongqing University of Science and Technology Chongqing 400042 P. R. China college of {1. and Information Science Shaanxi Normal University Xi'an 710062 P. R. China

Using the technique of block-operators, in this note, we prove that if P and Q are idempotents and （P - Q）^2n＋1.is in the trace class, then （P - Q）^2m＋1.is also in the trace class and tr（P - Q）^2m＋1.= dim（k（P） ∩ k（Q）^⊥） -dim（k（P）^⊥ N k（Q））, for all m ≥ n. Moreover, we prove that dim（k（P）∩ k（Q）^⊥） = dim（k（P）^⊥ ∩k（Q）） if and only if there exists a unitary U such that UP = QU and PU = UQ, where k（T） denotes the range of T. Keywords Fredholm, orthogonal projection, positive operator

关键词： Fredholm orthogonal projection positive operator

Doubly contracted CI method and applications

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Science China Chemistry 2004年第4期47卷 276-282页

作者： WANG Yubin1. HAN Huixian1. ZHAI Gaohong2 ,SUO Bin1.& WEN Zheny1.2 1. Institute of Modern physics, Northwest University, Xian 71.069, China 2. Laboratory of Physico-Inorganic Chemistry, Department of Chemistry, Northwest University, Xian 71.069,China Correspondence should be addressed to Wen Zhenyi 1. Institute of Modern physics Northwest University 710069 Xian China 2. Laboratory of Physico-Inorganic Chemistry Department of Chemistry Northwest University 710069 Xi’an China

Based on the hole-particle correspondence an approximate so-called doubly contracted CI scheme is proposed. Examples calculated based on the doubly contracted CI (DCCI) scheme show that the number of configurations after contraction is reduced by three orders of magnitude, and the computation time is reduced by an order of magnitude. The examples also show that compared with experiments the DCCI and uncontracted CI have similar and reasonable accuracy to some spectroscopic parameters.

关键词： doubly contracted CI hole-particle symmetry approximate MRCI

A Conceptual Model of Somali Jet Based on the Biot-Savart Law

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Chinese physics Letters 2008年第12期25卷 4321-4324页

作者：冯士德董平钟霖浩 LACS and LASG Institute of Atmospheric Physics Chinese Academy of Sciences PO Box 9804 Beijing 100029 School of Engineering Physics and Mathematics University of Dundee Dundee DD1 4HN United Kingdom

We study the relationship between thermal conditions on the earth bottom boundary and the formation of Somali jet based on the Biot-Savart law and the data from National Centres for Environmental Prediction （NCEP）. As the radiation from the Sun gradually moves from the southern meridian, the temperature on the surface of Somali Peninsular and Arabic Peninsular gradually increases. During the same period the surface temperature of the Northern Indian Ocean increases much slower. It is shown that this increase of the temperature difference between the land and sea is inductive to the formation and development of Rayleigh-Benard convection and leads to the increasing relative vorticity strength between positive and negative vertical vortices over the land and sea. According to the Biot-Savart law, increase of vorticity strength will correspondingly induce the horizontal velocity. A pair of positive and negative vorticity fields over the two Peninsulars and the sea surface is effective in forming and maintaining this current. This mechanism is referred to as the ＇Somali suction pump＇. It draws air continually from the Southern hemisphere and releases it at the coastal area of Somali.

关键词： EARTH temperature OCEAN temperature SOLAR radiation RAYLEIGH-Benard convection VORTEX motion ELECTRIC currents

High-Pressure Preparation of High-Density Cu_2ZnSnS_4 Materials

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Chinese physics Letters 2016年第7期33卷 113-116页

作者：李一鸣邱利霞丁战辉李永峰姚斌肖振宇朱品文 State Key Laboratory of Superhard Material and college of {1. Jilin University Key Laboratory of physics and Technology for Advanced Batteries(Ministry of Education) College of PhysicsJilin University

High-density Cu2ZnSnS4 （CZTS） materials are prepared via the mechanical alloying and high pressure sintering method using Cu2S, ZnS and SnS2 as the raw materials. The morphological, structural, compositional and electrical properties of the materials are investigated by using x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectroscopy, as well as by the Raman scattering and the Hall EFfect measurements. The CZTS synthesized under 5 GPa and 800℃ shows a p-type conductivity, with a resistivity of 9.69 × 1.^-2 Ω.cm and a carrier concentration of 1.45 × 1.^20 cm-3. It is contributed to by the large grains in the materials reducing the grain boundaries, thus effectively reducing the recombination of the charge carriers.

关键词： of in ZnS it CZTS High-Pressure Preparation of High-Density Cu2ZnSnS4 Materials Cu

Lighting up aggregate emission of perylene diimide by leveraging polymerization-mediated through-space charge transfer and π-π stacking

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Science China Chemistry 2024年

作者： Suiying Ye Désirée Füglistaller Tian Tian Anjay Manian Sudhir Kumar Celine Nardo Andrew J.Christofferson Salvy P.Russo Chih-Jen Shih Jean-Christophe Leroux Yinyin Bao Institute of Pharmaceutical Sciences Department of Chemistry and Applied Biosciences ETH Zurich Vladimir-Prelog-Weg 3 Institute for Chemical and Bioengineering Department of Chemistry and Applied Biosciences ETH Zurich Vladimir-Prelog-Weg 1-5 ARC Centre of Excellence in Exciton Science School of Science RMIT University School of Science STEM College RMIT University

The molecular engineering of fluorescent organic/polymeric materials, specifically those emitting in the deep red to near-infrared spectrum, is vital for advancements in optoelectronics and biomedicine. Perylene diimide(PDI), a well-known fluorescent scaffold, offers high thermal and photophysical stability but suffers from fluorescence quenching in solid or aggregate states due to intense π-π interactions. To mitigate this, simple and versatile methods for strong PDI aggregate emission without extensive synthetic demands are highly desirable but still lacking. Here, we report a straightforward strategy to enhance the solid-state emission of PDI by introducing certain degree of through-space charge transfer(TSCT) via controlled radical polymerization,which can efficiently distort the typical face-to-face PDI stacking, enabling greatly enhanced deep red emission. This is achieved by growing electron-donating star-shape styrenic(co)polymers from a multidirectional electron-accepting PDI initiator. The incorporation of polycyclic aromatic monomers further shifted the emission into the near-infrared region, albeit with a reduced intensity. Overall, the emission of the PDI-based TSCT polymers can be systematically manipulated by leveraging the balance between PDI stacking and the TSCT degree, as confirmed by both experimental study and theoretical calculations. Our approach circumvents complex synthetic procedures, offering highly emissive materials with large Stokes shifts and showing broad potential for optoelectronic technology.

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UNIFORM ESTIMATE ON FINITE TIME RUIN PROBABILITIES WITH RANDOM INTEREST RATE

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Acta Mathematica Scientia 2010年第3期30卷 688-700页

作者：明瑞星何晓霞胡亦钧刘娟 School of mathematics and Information Sciences Jiangxi Normal University School of mathematics and Statistics Wuhan University college of Science Wuhan University of Science and Technology college of {1. and Statistics Hubei Normal University

We consider a discrete time risk model in which the net payout （insurance risk） {Xk, k = 1. 2,...} are assumed to take real values and belong to the heavy-tailed class L∩ D and the discount factors （financial risk） {Yk, k = 1.2,...} concentrate on [θ, L], where 0 〈 0 〈 1. L 〈 ∞, {Xk, k = 1.2,...}, and {Yk, k=1.2,...} are assumed to be mutually independent. We investigate the asymptotic behavior of the ruin probability within a finite time horizon as the initial capital tends to infinity, and figure out that the convergence holds uniformly for all n ≥ 1. which is different from Tang Q H and Tsitsiashvili G （Adv Appl Prob, 2004, 36： 1.78-1.99）.

关键词： Random interest rate finite time ruin probability uniformity

Applying Hybrid Clustering in Pulsar Candidate Sifting with Multi-modality for FAST Survey

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Research in Astronomy and Astrophysics 2024年第3期24卷 283-296页

作者： Zi-Yi You Yun-Rong Pan Zhi Ma Li Zhang Shuo Xiao Dan-Dan Zhang Shi-Jun Dang Ru-Shuang Zhao Pei Wang Ai-Jun Dong Jia-Tao Jiang Ji-Bing Leng Wei-An Li Si-Yao Li School of physics and Electronic Science Guizhou Normal UniversityGuiyang 550025China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550025China college of Big Data and Information Engineering Guizhou UniversityGuiyang 550025China CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Key Laboratory of Information and Computing Guizhou Province Guizhou Normal UniversityGuiyang 550001China School of Big data and Computer Science Guizhou Normal UniversityGuiyang 550025China Guizhou Software Engineering Research Center Guiyang 550000China

Pulsar search is always the basis of pulsar navigation,gravitational wave detection and other research ***,the volume of pulsar candidates collected by the Five-hundred-meter Aperture Spherical radio Telescope(FAST)shows an explosive growth rate that has brought challenges for its pulsar candidate filtering ***,the multi-view heterogeneous data and class imbalance between true pulsars and non-pulsar candidates have negative effects on traditional single-modal supervised classification *** this study,a multi-modal and semi-supervised learning based on a pulsar candidate sifting algorithm is presented,which adopts a hybrid ensemble clustering scheme of density-based and partition-based methods combined with a feature-level fusion strategy for input data and a data partition strategy for *** on both High Time Resolution Universe SurveyⅡ(HTRU2)and actual FAST observation data demonstrate that the proposed algorithm could excellently identify pulsars:On HTRU2,the precision and recall rates of its parallel mode reach0.981.and 0.988 *** FAST data,those of its parallel mode reach 0.891.and 0.961.meanwhile,the running time also significantly decreases with the increment of parallel nodes within ***,we can conclude that our algorithm could be a feasible idea for large scale pulsar candidate sifting for FAST drift scan observation.

关键词： methods data analysis-surveys-methods numerical

Experimental study on the non-specularly reflected ultrasonic beam on a liquid-solid interface

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Science China mathematics 2001年第2期44卷 225-233页

作者：诸国桢刘亮傅德永 1. Department of physics Tsinghua University 100084 Beijing China 2. State Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences 100080 Beijing China

The reflected fields of a slightly divergent ultrasonic beam on a liquid-solid interface are recorded by a Schlieren system, and the lateral beam displacements on the interface are measured. The range of the incident anglei is around the Rayleigh anglec. The displacements are found to decrease as the incident angle increases. Theoretical calculation reveals that the displacements decrease with the increase in the incident angle for a divergent incident beam, but increase with that for a convergent one. The calculated curve of- i are in agreement with the experimental results.

关键词： ultrasonic beam liquid-solid interface

钼活化ZnIn_(2)S(4)光催化剂促进光催化析氢耦合苯甲醇氧化

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Science China Materials 2024年第8期67卷 2645-2652页

作者：俞杨帆尤晓萌张阳彭玉王雪璐刘鹏飞杨化桂 Key Laboratory for Ultrafine Materials of Ministry of Education Shanghai Engineering Research Center of Hierarchical NanomaterialsSchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China physics Department&Shanghai Key Laboratory of Magnetic Resonance School of Physics and Electronic ScienceEast China Normal UniversityShanghai 200062China

光催化水裂解制氢为解决能源危机提供了一条可行的途径.然而,四电子的水氧化反应迟缓严重制约了水的分解效率.本文中,掺杂Mo的ZnIn_(2)S(4);(Mo-ZIS)光催化剂通过与动力学上有利的苯甲醇(BA)的氧化反应协同整合,显著促进了析氢反应,高... 详细信息

光催化水裂解制氢为解决能源危机提供了一条可行的途径.然而,四电子的水氧化反应迟缓严重制约了水的分解效率.本文中,掺杂Mo的ZnIn_(2)S(4);(Mo-ZIS)光催化剂通过与动力学上有利的苯甲醇(BA)的氧化反应协同整合,显著促进了析氢反应,高价和不饱和Mo不仅促进光生载流子的分离,还促进BA的活化,从而加速BA的氧化.此外,Mo掺杂调节了ZIS的能带结构,增强了光催化剂的氧化能力,而不会引起BA的过度氧化.结果表明,Mo-ZIS光催化剂在不需要贵金属助催化剂的情况下,具有较高的析氢速率(1.,353μmol g^(-1.h^(-1.)和苯甲醛产率(1.,942μmol g^(-1.h^(-1.),显著优于ZIS光催化剂.引人注意的是,通过调节BA与溶剂之间的氢键网络强度来调节中间体在Mo-ZIS表面的解吸过程,Mo-ZIS的BAD产率为23,068μmol g^(-1.h^(-1.,相比于乙腈溶液中的反应速率提高了65%.本研究提出了一种有价值的将光催化制氢与选择性有机产物转化相结合的策略,为开发新型光催化剂,实现高效太阳能转化提供了新的见解.

关键词：光催化剂氢键网络析氢反应光生载流子过度氧化反应迟缓能源危机解吸过程