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Synthesis, separation and identification of dinitropyrene isomers

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Journal of Environmental sciences 1993年第1期5卷 54-62页

作者： Wang Hai, Li Baoqin, xu Weibing, Jin Zuliang xu XiaobaiResearch Center for Eco-Environmental sciences, chinese academy of sciences, beijing 100085, china

Dinitropyrenes (DNP) were prepared by nitration of pyrene, and the product was characterized by MS and elemental analysis. Three isomers of DNP were separated by HPLC and identified by 1H-NMR. The eating sequence on the normal phase column is 1, 3-DNP, 1, 6-DNP and 1, 8-DNP, whereas is 1, 6-DNP, 1. 8-DNP and 1. 3-DNP on the reversed phase column. The separation of three DNP isomers under different chromatographic conditions was also discussed.

关键词： dinitropyrenes environmental pollutant mutagen polycyclic aromatic hydrocarbon nitro-polycyclic aromatic hydrocarbon.

Nonlinear interactions between gravity waves and background winds

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Progress in Natural Science:Materials International 2007年第6期17卷 639-644页

作者： Liu Xiao1,2 and xu Jiyao1(1. State Key Laboratory for Space Weather, Center for Space Science and Applied Research, chinese academy of sciences, beijing 100080, china 2. Graduate University of chinese academy of sciences, beijing 100039, china) [a]State Key Laboratory for Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China [b]Graduate University of chinese academy of sciences Beijing China

Using the nonlinear propagating gravity waves (GW) model in the two-dimensional compressible atmosphere and the linear GW theory, the process of GW propagation in different background winds, e.g. the direction of the background wind is opposite to (dead wind) or the same as (tail wind) the direction of the horizontal phase velocity of GW, is studied. The results show that the dead wind prolongs the vertical wavelength and accelerates GW propagation. Therefore, GW propagates up to a higher height becomes instable in a short time and eventually induces an inverse jet flow. Then, the vertical wavelength is becoming short due to the nonlinear interactions between GW and the inverse jet flow. The vertical wavelength and group velocity decrease after GW propagates into the tail wind. The initial instable time is delayed. Although most of GW is trapped in the instable region, some of GW propagates above the instable region. Compared with GW propagation in the tail wind, the nonlinear interactions between GW and the dead wind are also strong. In contrast, the linear GW theory predicts that GW can propagate freely in the dead wind. The vertical wavelength simulated by the nonlinear numerical model is different from that predicted by the linear theory greatly after GW propagates into the dead wind.

关键词： gravity waves background winds vertical group velocity vertical wavelength nonlinear interactions.

GIS-based analysis of forest degradations in Baihe Forestry Bureau,northeast china

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Science china(Technological sciences) 2006年第z1期49卷 167-176页

作者： ZHOU Li, DAI Limin , Guofan Shao, xu Dong, WANG Hui & BAI Jianwei Institute of Applied Ecology, chinese academy of sciences, Shenyang 110016, china Graduate University of chinese academy of sciences, beijing 100101, china Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907, USA Department of City Development, Jinan University, Jinan 250002, china academy of Forest Inventory and Planning, State Forestry Administration, beijing 100714, china 1. Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 China 2. Graduate University of chinese academy of sciences Beijing 100101 China 3. Department of Forestry and Natural Resources Purdue University West Lafayette IN 47907 USA 4. Department of City Development Jinan University Jinan 250002 China 5. academy of Forest Inventory and Planning State Forestry Administration Beijing 100714 China

Forests in the Changbai Mountains are important timber sources for economic development of the society and provide ecological services in northeast china. In order to strengthen forest resource management, this paper analyzed management-induced changes in forest structure, tree species composition and forest landscape pattern from 1987 to 2000 for Baihe Forestry Bureau in Jilin Province based on digitized forest parcel maps and forest survey data. The results suggested that the area of Mature, High-Stocking, and Close-Canopy Forests decreased by 31.4%, 55.9% and 10.7% respectively; volume of Mixed Forest, the native forest vegetation type, decreased by 17.8%;the number of patches increased tremendously but the mean patch density decreased sharply for Mature, High-Stocking, Close-Canopy, and Mixed Forests. All the changes in forest structure, species composition, and landscape pattern indicated severe degradations going on with the forests in Baihe Forestry Bureau. Because of the effect of degradation to forest services, restoring forest resources and protecting biodiversity has become urgently important. The strategies of sustainable forest management need to be worked out and implemented.

关键词： geographic information system, forest management, Changbai Mountains, forest change, forest decline.

Input function and simulated distributions of tritium in the North Pacific

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Science china Earth sciences 2010年第3期53卷 441-453页

作者： BA Qi1,2 & xu YongFu1 1 State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, chinese academy of sciences, beijing 100029, china 2 Graduate University of chinese academy of sciences, beijing 100049, china 1. State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China

An ocean general circulation model (OGCM) of the North Pacific with a southern open boundary condition is used to simulate the distribution and transport of tritium in the North Pacific. First, the observed tritium in precipitation dataset of GNIP/ISOHIS is chosen, and used to develop an input function of tritium for the model domain from 1951 to 1997 in terms of the triangulation for interpolation. Then, the input function is used as an upper flux for the tritium model. The OGCM with tritium is integrated for 47 years with the initial condition of zero tritium concentrations. Compared with the observations from GEOSECS and WOCE, the model generates a meridional gradient of surface tritium concentrations and the high tritium concentrations in the subsurface layer, which is consistent with that indicated in the observations. The simulated time series of total tritium fluxes from the atmosphere to the ocean shows a spike in 1963. The total inventory of tritium in the ocean changes slowly with time after 1975. Tritium enters the higher-latitude region, and then is mainly transported by the subsurface process towards the equatorial region, which is well simulated in the model. However, the difference mainly occurs at 30°N–40°N, which can be seen also in the simulation of CFCs. This difference may partly originate from the insufficient description of physical processes in the OGCM. Nevertheless, some uncertainties exist in the development of the tritium input function, which can also influence the simulated results.

关键词： North Pacific basin-wide ocean general circulation model tritium input function tritium distributions

Effects of fundamental structure parameters on dynamic responses of submerged floating tunnel under hydrodynamic loads

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Acta Mechanica Sinica 2009年第3期25卷 335-344页

作者： xu Long Fei Ge Lei Wang Youshi Hong State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, chinese academy of sciences, beijing 100190, china State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China

This paper investigates the effects of structure parameters on dynamic responses of submerged floating tunnel （SFT） under hydrodynamic loads. The structure parameters includes buoyancy-weight ratio （BWR）, stiffness coefficients of the cable systems, tunnel net buoyancy and tunnel length. First, the importance of structural damp in relation to the dynamic responses of SPT is demonstrated and the mechanism of structural damp effect is discussed. Thereafter, the fundamental structure parameters are investigated through the analysis of SFT dynamic responses under hydrodynamic loads. The results indicate that the BWR of SFT is a key structure parameter. When BWR is 1.2, there is a remarkable trend change in the vertical dynamic response of SFT under hydrodynamic loads. The results also indicate that the ratio of the tunnel net buoyancy to the cable stiffness coefficient is not a characteristic factor affecting the dynamic responses of SFT under hydrodynamic loads.

关键词： Submerged floating tunnel Structural dampBuoyancy-weight ratio Cable stiffness coefficient ,Tunnel net buoyancy - Hydrodynamic load

Quenching of zinc phthalocyanine excited states by viologen surfactant assemblies——The influence of microenvironment

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chinese Journal of Chemistry 1993年第2期11卷 120-125页

作者： LIU,Ji-Xiang ZHOU,Qing-Fu xu,Hui-Jun Institute of Photoyraphic Chemistry,chinese academy of sciences,beijing 100101 Institute of Photographic Chemistry Chinese Academy of Sciences Beijing 100101

A series of functional surfactants of N-alkyl-N'-butyl viologens has been synthesized. The quenching of excited singlet and triplet states of zinc phthalocyanine was studied in DMSO and in mixed micelles containing the functional surfactant as one and cationic cetyl trimethylam- monium bromide(CTAB),anionic sodium dodecylsulfate(SDS)and neutral TX-100 surfactant as the other *** quenching and laser photolysis studies indicate that the functional surfactants are solubilized at different sites in micelles,the process depends on chain length and exerts great influence on the quenching of zinc phthalocyanine excited states.

关键词： CTAB nm Quenching of zinc phthalocyanine excited states by viologen surfactant assemblies The influence of microenvironment

Synthesis and Effect of Cation Binding on Photophysical Properties of 1,8-Anthraceno-18-Crown-5

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chinese Chemical Letters 1999年第12期10卷 0-0,0-0页

作者： Hua JIANG Hui Jun xu Pei Jie XIA Qing Fu ZHOU(Laboratory of Photochemistry, Institute of Photographic Chemistry,chinese academy of sciences, beijing 100101) chinese Acad Sci Inst Photog Chem Lab Photochem Beijing 100101 Peoples R China

A new type of anthracene crown ether 1, 8-anthraceno-18-crown-5 has been synthesizedand the photophysical properties upon complexation with alkali and alkaline-earth metal canonswere investigated. The fiuorescence quantum yield and lifetime are appreciably enhanced, and thestability constant Ks were determined by fluorometric titration. It was found that the magnitude ofKs is controlled by the size and charge density of the complexed canons.

关键词： Crown ether photophysical property canon-binding.

Multi-dimensional versions of a formula of Popoviciu

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Science china Mathematics 2007年第2期50卷 285-291页

作者： Zhi-qiang xu Institute of Computational Math and Sci/Eng Computing, academy of Mathematics and Systems Science, chinese academy of sciences, beijing 100080, china 1. Institute of Computational Math and Sci/Eng Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China

In this paper, an explicit formulation for multivariate truncated power functions of degree one is given firstly. Based on multivariate truncated power functions of degree one, a formulation is presented which counts the number of non-negative integer solutions of s×(s + 1) linear Diophantine equations and it can be considered as a multi-dimensional versions of the formula counting the number of non-negative integer solutions of ax + by = n which is given by Popoviciu in 1953.

关键词： multivariate splines discrete truncated power linear Diophantine equations 41A15 05A15

Production of β-1,3-glucanase and chitinase of two biocon-trol agents and their possible modes of action

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chinese Science Bulletin 2002年第4期47卷 292-296页

作者： FAN Qing, TIAN Shiping, LIU Haibo & xu YongInstitute of Botany, chinese academy of sciences, beijing 100093, china Institute of Botany Chinese Academy of Sciences Beijing China

Pichia membranefaciens Hansen and Candida guilliermondii (Cast) Langeronet Guerra are two antagonists of R. stolonifer on harvested nectarine and peach fruits. In this study, β-1,3-glucanase and chitinase activities of the antagonists were induced in vitro and in vivo. The highest β-1, 3-glucanase activity was detected in Lilly-Barnett minimal salt medium supplemented with glucose in combination with CWP of R. stolonifer as a carbon source. The β-1,3-glucanase activity of P. membranefaciens reached the maximum level, being 114.0 SU (specific activity unit), and that of C. guilliermondii reached 103.2 SU. The lowest β-1,3-glucanase activity was observed in the medium containing glucose as sole car-bon source. P. membranefaciens was able to produce signifi-cantly higher levels of chitinase (exochitinase and endochiti-nase) in vitro than C. guilliermondii grown in Czapeck mini-mal medium. An increase in β-1,3-glucanase and chitinase activity was also triggered by wounding, adding of carbon sources

关键词： biological control yeast rhizopus rot β-1 3-glucanase chitinase.