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Study on the atmospheric photochemical reaction of CF_3.radicals using ultraviolet photoelectron and photoionization mass spectrometer

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Science china Chemistry 2008年第4期51卷 316-321页

作者： YAO Li1,2. DU Lin1,2. YIN Shi1,2.& GE MaoFa1 1 {3. National Laboratory for Molecular sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, {2. of Chemistry, Chinese academy of sciences, beijing 100080, china 2.Graduate University of Chinese academy of sciences, beijing 100080, china beijing National Laboratory for Molecular sciences (BNLMS) State Key Laboratory for Structural Chemistry of Unstable and Stable Species Institute of Chemistry Chinese Academy of Sciences Beijing China Graduate University of Chinese academy of sciences Beijing China

A study of the atmospheric photochemical reaction of CF3.radical with CO and O2.was performed by using a homemade ultraviolet photoelectron spectrometer-photoionization mass spectrometer (PES- PIMS). The electronic structures and mechanism of ionization and dissociation of CF3.C(O)OOC(O)- OCF3.were investigated. It was indicated that the two bands on the photoelectron spectrum of CF3.C(O)OOC(O)OCF3.are the result of ionization of an electron from a lone pair of oxygen and a fluo- rine lone pair of CF3.group. The outermost electrons reside in the oxygen lone pair. The experimental and theoretical first vertical ionization energy is 13.2. and 13.178 eV, respectively, with the PES and OVGF method. They are in good agreement. The photo ionization and dissociation processes were discussed with the help of theoretical calculations and PES-PIMS experiment. After ionization, the parent ions prefer the dissociation of the C-O bond and giving the fragments CF3.CO+ and CF3.. It demonstrated that the ultraviolet photoelectron and photoionization mass spectrometer could be ap- plied widely in the study of atmospheric photochemical reaction.

关键词： photochemical reaction CF3 radical ultraviolet photoelectron and photoionization mass spectroscopy transient species

GAUSS-SEIDEL-TYPE MULTIGRID METHODS

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Journal of Computational Mathematics 2003年第4期21卷 421-434页

作者： Zhao-hui Huang Qian-shun Chang (academy of Mathematics and System sciences, Chinese academy of sciences, beijing 100080, china) academy of Mathematics and System sciences Chinese Academy of Sciences 北京 100080

By making use of the Gauss-Seidel-type solution method, the procedure for computing the interpolation operator of multigrid methods is simplified. This leads to a saving of computational time. Three new kinds of interpolation formulae are obtained by adopting different approximate methods, to try to enhance the accuracy of the interpolatory operator. A theoretical study proves the two-level convergence of these Gauss-Seidel-type MG methods. A series of numerical experiments is presented to evaluate the relative performance of the methods with respect to the convergence factor, CPU-time(for one V-cycle and the setup phase) and computational complexity.

关键词： Multigrid methods Gauss-Seidel solution Interpolation formula Convergence.

Solving the input data in error correc-tion of optical fabrication by finite Fourier coefficient algorithm

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Science china(Technological sciences) 2006年第1期49卷 50-60页

作者： CHENG Haobo1,2. SUN Guozheng3.& FENG Zhijing2.1. Department of Optical Engineering, beijing {3. of {2., beijing 100081, china 2. Department of Precision Instruments and Mechanology, Tsinghua University, beijing 100084, china 3. china North Industries Group Corporation, beijing 100089, china Department of Optical Engineering Beijing Institute of Technology Beijing China Department of Precision Instruments and Mechanology Tsinghua University Beijing China china North Industries Group Corporation Beijing China

A free-form lens (FFL) is a special surface that is difficult to be fabricated. FFL are usually fabricated by computer-controlled optical surfacing (CCOS) technique. During CCOS, the material removal amount is determined by the unit removal function (URF) convoluting with the input data――the dwell time. When the removal amount and the URF are known, how to solve the input data involves the special algorithm――deconvolution. Usually, the input data are solved by virtue of low pass filter or iterative methods. However, an approximation solution would destroy the machining stability nec-essary to perform precisely CCOS. In this paper, to solve the input data, a new method that is based on the finite Fourier coefficient is put forward. It can give a continuous and accurate solution for fabricating choice. Several parameters are simulated, which influ-ence the process of CCOS, and evaluating on the effect of the method is also carried out. Experimental results verify that this method is suitable for guiding the manufacturing of high precision FFL.

关键词： optical fabrication, computer controlled optical surfacing, free-form lens, finite Fourier coefficient, error correction.

A shortest path algorithm for moving objects in spatial network databases

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Progress in Natural Science:Materials International 2008年第7期18卷 893-899页

作者： Xiaolan Yin a,b,*, Zhiming Ding c, Jing Li a a technology Center of Software Engineering, institute of Software, Chinese {2. of Science, P.O. Box 8718,{3., china b Graduate University, Chinese {2. of sciences, beijing 100049, china c technology Center of Basic Software, institute of Software, Chinese {2. of sciences,{3., china technology Center of Software Engineering Institute of Software Chinese Academy of Science P.O. Box 8718 Beijing 100080 China Graduate University Chinese Academy of Sciences Beijing 100049 China technology Center of Basic Software Institute of Software Chinese Academy of Sciences Beijing 100080 China

One of the most important kinds of queries in Spatial Network Databases (SNDB) to support location-based services (LBS) is the shortest path query. Given an object in a network, e.g. a location of a car on a road network, and a set of objects of interests, e.g. hotels, gas station, and car, the shortest path query returns the shortest path from the query object to interested objects. The studies of shortest path query have two kinds of ways, online processing and preprocessing. The studies of preprocessing suppose that the interest objects are static. This paper proposes a shortest path algorithm with a set of index structures to support the situation of moving objects. This algorithm can transform a dynamic problem to a static problem. In this paper we focus on road networks. However, our algorithms do not use any domain specific information, and therefore can be applied to any network. This algorithm’s complexity is O(klog2.), and traditional Dijkstra’s complexity is O((i + k)2..

关键词： Moving object Spatial network databases Shortest path index Shortest path

Photogeneration of the free radicals and singlet oxygen by chrysophanol from rheum

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Science china Chemistry 2004年第5期47卷 381-387页

作者： RAO Jing1,2. XIE Jie1, ZHAO Jingquan1 & ZHU Teng2.1. Key Laboratory of Photochemistry, Center for Molecular Science, institute of Chemistry, The Chinese {3. of {2., beijing 100080, china 2. University of Science and technology beijing, beijing 10083. china Key Laboratory of Photochemistry Center for Molecular Science Institute of Chemistry The Chinese Academy of Sciences Beijing China University of Science and technology beijing Beijing China

In the current work, chryosphanol (MHAQ) was isolated and purified from rheum, and the photosensitization activities were studied. In nitrogen-saturated DMSO solution, irradia- tion of chryosphanol (MHAQ) with visible light (>43. nm) produced the semiquinone radical anions (MHAQ??), which was intensified significantly by an electron donor NADH, suggesting electron transfer between the excited and ground state photosensitizer molecules. In an air-saturated DMSO solution, superoxide radical anions (O2.), trapped by DMPO, were detected. ?? It was proved that O2.was not originated from the singlet oxygen (1O2. but dependent on DMPO, ?? chrysophanol, oxygen and the irradiation time. The singlet oxygen and OH could also be pro- ? duced by the photosensitization of the photosensitizer. These suggest that chrysophanol pos- sesses the photosensitization activity via Type I mechanism and Type II mechanism. To evaluate the photosensitization activities of MHAQ, emodin and mixed anthraquinone derivatives ex- tracted from rheum, the relative productivities of O2.were estimated to be 1.8, 1.1 and 1.0 re- ?? spectively and the quantum yields for singlet oxygen to be 0.3., 0.53.and 0.14 respectively. Therefore, these low-cost pigments may be potentially used as phototherapeutic medicine for some kind of vascular diseases or photo-activated pesticides.

关键词： chrysophanol, ESR, semiquinone radical anions, superoxide radical anions, hydroxyl radical, singlet oxygen.

Flow Instability and Its Control in Compression Systems

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Journal of Thermal Science 2003年第1期12卷 1-9页

作者： Jingyi Cheninstitute of Engineering Thermophysics, Chinese academy of {2.,{3., china institute of Engineering Thermophysics Chinese Academy of Sciences Beijing China

This paper reviews the development in the research of flow instability and its control over the recent ten or more years. This development was largely stimulated by the novel idea of active control of the aerodynamic instability in compressors. Three topics are covered in the paper, which appeared as the major themes towards the goal of stability enhancement. The first topic is the pre-stall behavior of rotating stall, which plays a vital role in designing the control scheme and discovering the convenient route to find the causal factors of flow disturbances potentially leading to stall. The second topic is the mechanism of blade passage flow during stall and its inception, which is the basic knowledge needed to manipulate the blade design for the stability improvement and eventually to predict the unsteady performance of the compressor system. The third topic is the recent trend of the control strategy based on the learning of active vs. passive methods. To introduce to the discussion of these topics, a brief description of the history of the recent development is given at the beginning of the paper. In discussing each topic, future works are also highlighted to enhance the further development of this long-standing problem in turbomachinery research and application.

关键词： compressors rotating stall pre-stall active/passive control wavelet.

Phase relationship of complex multi-component system in chromate cleaner production

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Progress in Natural Science:Materials International 2007年第7期17卷 845-850页

作者： Ge Xinlei~1 Wang Xidong~(1,3.*) Zheng Shili~2.Zhang Mei~1 Zhang Yi~2.(1.Department of Physical Chemistry,University of Science and technology {3.,{3. 100083.china 2.institute of Process Engineering,Chinese academy of sciences,{3. 100080,china 3.College of Engineering,Peking University,{3. 100871,china) Department of Physical Chemistry University of Science and Technology Beijing Beijing 100083 China College of Engineering Peking University Beijing 100871 China institute of Process Engineering Chinese Academy of Sciences Beijing 100080 China

The phase relationships of the complex multi-component systems in the liquid-phase oxidization and separation process related with the chromate cleaner production are investigated theoretically and *** phase diagram of main system Fe- Cr2.4-KOH-O2.f oxidization process and the relationship of its standard Gibbs free energy change with temperature are calculated.A se- ries of phase diagrams of the separation process at different temperatures,such as K（Na）OH-K（Na）2.rO4-H2.,KOH-KAlO2.H2., K（Na）OH-K（Na）2.O3.H2.,K（Na）OH-K（Na）HCO3.H2. and K（Na）HCO3.K（Na）2.rO4-H2. have also been *** ex- periments are carried out to verify the calculated *** results showed that the sub-molten salt media are suitable for the oxidization and separation processes;FeCr2.4can be oxidized across a wide range of temperature;K（Na）2.rO4can be separated from K（Na）AlO2.ystem at appropriate temperature and proper concentration;the crystallization of carbonate is easier than that of K（Na）2.rO4.

关键词： chromite chromate system thermodynamics calculation phase diagram

Optimal reactions for the synthesis of superheavy nucleus ^(2.0)Hs

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Science china(Physics,Mechanics & Astronomy) 2006年第6期49卷 641-648页

作者： LIU Zuhua1,3.& BAO Jingdong1,2.1. Key Laboratory of Beam technology and Material Modification of Ministry of Education, beijing Normal University, beijing 100875, china 2. Physics Department, beijing Normal University, beijing 100875, china 3. china institute of Atomic Energy, beijing 102.13. china Key Laboratory of Beam technology and Material Modification of Ministry of Education Beijing Normal University Beijing China china institute of Atomic Energy Beijing China Physics Department Beijing Normal University Beijing China

The superheavy nucleus 2.0Hs is expected to be a “double-magic” deformed nucleus. We have calculated its cross sections of evaporation residue for the reactions 2.8Cm(2.Mg,4n)2.0Hs, 2.4Pu(3.Si,4n)2.0Hs, 2.8U(3.S,4n)2.0Hs and 2.6Ra(48Ca,4n)2.0Hs using a two-parameter Smoluchowski equation. It is found from our results that 2.6Ra(48Ca,4n)2.0Hs and 2.8U(3.S,4n)2.0Hs are two optimal reactions for the synthesis of the superheavy nucleus 2.0Hs due to their large negative Q-values.

关键词： diffused fusion barrier,Smoluchowski equation,superheavy nuclei.

ON THE EXPLICIT COMPACT SCHEMES II: EXTENSION OF THE STCE/CE METHOD ON NONSTAGGERED GRIDS ON THE EXPLICIT COMPACT SCHEMES II: EXTENSION OF THE STCE/CE METHOD ON NONSTAGGERED GRIDS

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Journal of Computational Mathematics 2000年第5期18卷 467-480页

作者： Hua-zhong Tang , Hua-mu Wu (State Key Laboratory of Scientific and Engineering computing, institute of Computational Mathematics, Chinese {2. of {3., beijing 100080, china) 中科院计算数学所科学与工程计算国家重点实验室北京 100080

This paper continues to construct and study the explicit compact (EC) schemes for conservation laws. First, we axtend STCE/SE method on non-staggered grid, which has same well resolution as one in [1], and just requires half of the computational works. Then, we consider some constructions of the EC schemes for two-dimensional conservation laws, and some 1D and 2. numerical experiments are also given.

关键词： Conservation laws Compact scheme Shock-Capturing method Euler equations.