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排序方式: 共有114条查询结果,搜索用时 15 毫秒
31.
Raevsky O Andreeva E Raevskaja O Skvortsov V Schaper K 《SAR and QSAR in environmental research》2005,16(1-2):191-202
32.
WANG Yue BI Xiao-Jun CUI Shu-Wang DING Lin-Kai DAN Zeng-Luo-Bu DING Xiao-Hong FAN Chao FENG Cun-Feng FENG Zhao-Yang FENG Zhen-Yong GAO Xiao-Yu GENG Qing-Xi GUO Hong-Wei HE Hui-Hai HE Mao HU Hai-Bing HU Hong-Bo HUANG Qing JIA Huan-Yu LA Ba-Ci-Ren LE Gui-Ming LI Ai-Feng LI Jin-Yu LOU Yu-Qing LU Hong LU Sui-Ling MENG Xian-Ru MU Jun REN Jing-Ru TAN You-Heng WANG Bo WANG Hui WANG Yong-Gang WU Han-Rong XUE Liang YANG Xian-Chu YE Zong-Hai YU Guang-Ce YUAN Ai-Fang ZHANG Hui-Min ZHANG Ji-Long ZHANG Nai-Jian ZHANG Xue-Yao ZHANG Yong ZHANG Yi ZHA Xi-Sang-Zhu ZHOU Xun-Xiu YUAN Qiang 《中国物理C(英文版)》2008,32(11)
Using the data taken from Tibet Ⅱ High Density (HD) Array (1997 February--1999 September) and Tibet-Ⅲ array (1999 November--2005 November), our previous northern sky survey for TeV γ-ray point sources has now been updated by a factor of 2.8 improved statistics. From 0.0° to 60.0° in declination (Dec) range, no new TeV γ-ray point sources with sufficiently high significance were identified while the well-known Crab Nebula and Mrk421 remain to be the brightest TeV T-ray sources within the field of view of the Tibet air shower array. Based on the currently available data and at the 90% confidence level (C.L.), the flux upper limits for different power law index assumption are re-derived, which are approximately improved by 1.7 times as compared with our previous reported limits. 相似文献
33.
D. W. Scheuch U. Schaper W. Förster H. Kühn T. Schewe 《Fresenius' Journal of Analytical Chemistry》1986,324(3-4):368-369
Conclusions The data presented in this paper together with the findings of Hagmann et al. [4] suggest an important role of metabolites of the lipoxygenase pathway in the pathogenesis of endotoxin shock. Selective inhibition of lipoxygenase by FLM 5011 prevented the development of irreversible shock state nearly completely decreasing the mortality rate to 0.05. p ]Further investigations on the precise mechanism of the action of lipoxygenase metabolites are necessary to evaluate their actual significance in the complex pathogenesis of circulatory shock.
Hemmung des Lipoxygenase-Weges erhöht die Überlebensrate im Endotoxin-Schock相似文献
34.
Abstract This paper is devoted to investigate extinction and nonextinction conditions of the extended Beverton–Holt equation (BHE) for dynamics of populations in Ecology when potential discontinuities at sampling points are included in the model. The proposed model is described by means of four sequences of parameters. Two of them are the intrinsic growth rate and the carrying capacity sequences which are included in the basic BHE model. The other two ones, namely, the harvesting (i.e., the hunting or fishing quota) and the internal consumption (which can include positive and negative migrations in the considered population habitat) sequences are included to parameterize the model discontinuities. Such discontinuities are related to impulses in the corresponding continuous‐time logistic equation. The obtained results establish how the harvesting quota and/or the internal consumption has to be fixed to guarantee the population nonextinction or, eventually, its extinction. Finally, some controllability results related to the search of a carrying capacity sequence such that the solution of the proposed impulsive BHE tracks a reference one are obtained. 相似文献
35.
Biemann L Häber T Maydt D Schaper K Kleinermanns K 《The Journal of chemical physics》2011,134(11):115103
We investigated the self-aggregation of 2'-deoxy-3',5'-bis(tert-butyldimethylsilyl)-cytidine dC(TBDMS)(2) in CDCl(3) solutions by Fourier transform infrared (FT-IR) spectroscopy and report the formation of larger aggregates than dimers in this solvent for the first time. The hydrogen bonding patterns in these complexes, which occur with increasing concentration may serve as a model for DNA super-structures such as triplexes. From the IR spectra, wavelength dependent absolute extinction coefficients of the monomer, dimer as well as a contribution from larger clusters which are supposedly trimers are deduced on the basis of a simple deconvolution method. Our results are supported by RI-B3LYP/TZVP calculations within the conductorlike screening model framework, to account for solvent effects in the ab initio calculations. 相似文献
36.
37.
R. Dersch Taiqi Liu A. K. Schaper A. Greiner J. H. Wendorff 《Journal of polymer science. Part A, Polymer chemistry》2003,41(4):545-553
Electrospinning gives rise to polymer nanofibers. The spinning process is characterized by strong deformations of the polymer material taking place during the spinning process and a very rapid structure formation process happening within milliseconds. We were interested in the influence of the peculiar spinning process on the structures of nanofibers. For this purpose, we analyzed the internal structures of nanofibers spun from polyamide‐6 and polylactide with an average diameter of about 50 nm. The fibers were partially crystalline, with degrees of crystallinity not significantly smaller than those found for less rapidly quenched and much thicker melt‐extruded fibers. The annealing of polyamide fibers at elevated temperatures resulted in a transformation from the disordered γ modification to the more highly ordered α modification, and this again was in close agreement with the response of melt‐extruded fibers. The orientation of the crystals along the fiber axis was strongly inhomogeneous: it was, on average, very weak, yet it could be quite pronounced locally. Small elongations of approximately 10% resulted in well‐developed homogeneous crystal orientations. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 545–553, 2003 相似文献
38.
Schaper K 《Magnetic resonance in chemistry : MRC》2008,46(12):1163-1167
The synthesis of o-nitrosobenzoic acid 2 has been known for more than 100 years, and the photochemical preparation from o-nitrobenzaldehyde 1 became a textbook example for [1,5]-hydrogen shifts. However, neither the (1)H-NMR spectra nor the (13)C--{(1)H}-NMR of this compound have been reported so far. This fact can most likely be attributed to the monomer-dimer equilibrium of the nitrosobenzoic acid, which leads to rather complex, concentration-dependent NMR spectra. In this paper, we report a thorough investigation of these spectra. In the (13)C-{(1)H}-NMR spectra, all 21 lines could be assigned to the monomeric form, the E-dimer, and the Z-dimer. 相似文献
39.
40.
Gerrit Schaper Dr. Marco Wenzel Dr. Felix Hennersdorf Prof. Dr. Leonard F. Lindoy Prof. Dr. Jan J. Weigand 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(33):8484-8491
The reaction of UO2(OAc)2 ⋅ 2H2O with the biologically inspired ligand 2-salicylidene glucosamine (H2 L1 ) results in the formation of the anionic trinuclear uranyl complex [(UO2)3(μ3-O)( L1 )3]2− ( 1 2−), which was isolated in good yield as its Cs-salt, [Cs]2 1 . Recrystallization of [Cs]2 1 in the presence of 18-crown-6 led to formation of a neutral ion pair of type [M(18-crown-6)]2 1 , which was also obtained for the alkali metal ions Rb+ and K+ (M=Cs, Rb, K). The related ligand, 2-(2-hydroxy-1-naphthylidene) glucosamine (H2 L2 ) in a similar procedure with Cs+ gave the corresponding complex [Cs(18-crown-6)]2[(UO2)3(μ3-O)( L2 )3 ([Cs(18-crown-6)]2 2 ). From X-ray investigations, the [(UO2)3O( Ln )3]2− anion (n=1, 2) in each complex is a discrete trinuclear uranyl species that coordinates to the alkali metal ion via three uranyl oxygen atoms. The coordination behavior of H2 L1 and H2 L2 towards UO22+ was investigated by NMR, UV/Vis spectroscopy and mass spectrometry, revealing the in situ formation of the 1 2− and 2 2−dianions in solution. 相似文献