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排序方式: 共有366条查询结果,搜索用时 15 毫秒
1.
Lijuan Shen Li Li Sheng Lu Xiaohan Zhang Jie Liu Junlin An Guojun Zhang Bo Wu Fei Wang 《中国颗粒学报》2015,(3):10-15
We conducted measurements of black carbon(BC) aerosol in Jiaxing,China during autumn from September 26 to November 30,2013.We investigated temporal and diurnal variations of BC,and its correlations with meteorological parameters and other major pollutants.Results showed that hourly mass concentrations of BC ranged from 0.2 to 22.0 μg/m3,with an average of 5.1 μg/m3.The diurnai variation of BC exhibited a bimodal distribution,with peaks at 07:00 and 18:00.The morning peak was larger than the evening peak.The mass percentages of BC in PM2.5 and PM10 were 7.1%and 4.8%,respectively.The absorption coefficient of BC was calculated to be 44.4 Mm-1,which accounted for 11.1%of the total aerosol extinction.BC was mainly emitted from local sources in southwestern Jiaxing where BC concentrations were generally greater than 11 μg/m3 during the measurement period.Correlation analysis indicated that the main sources of BC were motor vehicle exhaust,and domestic and industrial combustion. 相似文献
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板壳塑性屈曲中的佯谬及其研究进展 总被引:6,自引:0,他引:6
本文详细论述了板壳塑性屈曲中的佯谬及其研究进展。并对现有的各种观点作了分析讨论。 相似文献
4.
CUI YuanQing & YANG Wei School of Aerospace Engineering Applied Mechanics Tongji University Shanghai China University Office Zhejiang University Hangzhou 《中国科学:物理学 力学 天文学(英文版)》2011,(5)
Experimental results indicate three regimes for cracking in a ferroelectric double cantilever beam (DCB) under combined electromechanical loading. In the loading, the maximum amplitude of the applied electric field reaches almost twice the coercive field of ferroelectrics. Thus, the model of small scale domain switching is not applicable any more, which is dictated only by the singular term of the crack tip field. In the DCB test, a large or global scale domain switching takes place instead, which is driven... 相似文献
5.
We propose a new analytical edge spread function (ESF) fitting model to measure the modulation transfer function (MTF).The ESF data obtained from a slanted-edge image are fitted to our model through the non-linear least squares (NLLSQ) method.The differentiation of the ESF yields the line spread function (LSF),the Fourier transform of which gives the profile of two-dimensional MTF.Compared with the previous methods,the MTF estimate determined by our method conforms more closely to the reference.A practical application of our MTF measurement in degraded image restoration also validates the accuracy of our model. 相似文献
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Lihua Chen Dept.of Math. Computer Science Fuqing Branch of Fujian Normal University Fuqing Fujian Jiaqi Mo Dept.of Math. Anhui Normal University Wuhu Anhui Faculty of Science Huzhou Teacher College Huzhou Zhejiang 《Annals of Differential Equations》2011,(4):434-439
An initial boundary value problem of semilinear nonlocal reaction diffusion equations is considered.Under some suitable conditions,using the asymptotic theory,the existence and asymptotic behavior of the interior layer solution to the initial boundary value problem are studied. 相似文献
7.
Jiang Mingxiao Zhu Weiqiu Zhejiang University Hangzhou P. R. China 《Acta Mechanica Solida Sinica》1996,9(2):169-178
Two stochastic models of fatigue crack growth under constant amplitude cyclic loadingare proposed and studied by using the stochastic averaging method and total probability theorem to ac-count for high frequency component and low frequency component, respectively, of the irregular na-ture of fatigue crack growth observed in Virkler's experiment. Particular attention is paid to the predic-tion performance of the models under a change in the initial crack length. It is shown that the modelsproposed in the present paper yields better agreement with experimental data than other models avail-able in literature. 相似文献
8.
Jie Ju Yu Jin Li Jian Rong Gao Jian Hong Jia Liang Han Wei Jian Sheng Yi Xia Jia 《中国化学快报》2011,22(4):382-384
An aqueous solution of hydrogen peroxide and hydrogen bromide illuminated by a 60 W incandescent light bulb serves as a source of bromine radicals.Various substituted toluenes(NO2,Cl,Br,H,CH3) were high selectively brominated at the benzyl position for monobromination in CH2C12 at ice water with catalyst free.This simple but effective bromination of toluene derivatives with an aqueous H2O2-HBr system is characterized with the use of inexpensive reagents and a lower impact on the environment, which make it a good alternative to the existing bromination methods. 相似文献
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ZHAO Xiao-ping JIN Ye-cheng ZENG Xing ZHANG Bo-li ZHANG Yu-feng .Tianjin State Key Laboratory of Modern Chinese Medicine Tianjin University of Traditional Chinese Medicine Tianjin P.R.China .College of Preclinical Medicine Zhejiang Chinese Medical University Hangzhou .College of Pharmaceutical Sciences Zhejiang University Hangzhou 《高等学校化学研究》2011,(4):562-565
In order to identify the potential nephrotoxic compounds in traditional Chinese medicine Lithospermum erythrorhizon,it was separated into serial fractions according to their polarities.An in vitro method was utilized to determine the nephrotoxicity of these fractions with the help of fluorescence image analysis.As a result,the primary fraction A05 and its secondary fractions C06 C09 and C12 C14 were found to have significant toxicity to LLC-PK1 cell line,as determined by the survive rate less than 20% after... 相似文献
10.
FU JunDan TANG ZhiWei FENG Xia & WEN YiHang Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces 《中国科学:化学》2010,(5)
Three d10 tetranuclear complexes,Cd 4(1,8-nap) 4(2,2′-bipy) 4(H2O) 8·6H2O(1,8-nap=naphthalene-1,8-dicarboxylate and 2,2′bipy=2,2′-bipyridine)(1),Cd4(1,8-nap) 4(2,2′-bipy) 4(H2O) 8·6H2O(2) andZn4(1,8-nap) 4(2,2′-bipy) 4(H2O) 4·2H2O(3),have been synthesized under hydrothermal conditions and characterized by elemental analyses,IR and X-ray diffraction techniques. Complexes 1 and 2 are isomers showing one-dimensional ribbon-like structures connected by O-H···O hydrogen bonds,and the one-dimensional ribbons are ... 相似文献