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961.
对一类边界条件是非线性的Laplace方程的Signorini问题,提出了基于投影不动点方程的边界元迭代算法。由于Signorini边界条件 * 等价于的不动点问题 *,因此可以通过投影迭代格式 * 来满足Signorini边界条件,从而每一次迭代只需要求解一个标准的椭圆型混合边值问题。由于该算法是在Signorini边界上进行迭代,因此边界元方法很适合用于数值求解。然后利用投影性质和Green公式证明了算法的收敛性。最后,算例的数值结果表明了该算法的可行性和有效性。(注:*表示公式,见正文) )
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962.
FY-3 satellite Ultraviolet Total Ozone Unit 总被引:4,自引:0,他引:4
WANG YongMei WANG YingJian WANG WeiHe ZHANG ZhongMou Lü JianGong FU LiPing JIANG Fang CHEN Ji WANG JiHong GUAN FengJun HUANG FuXiang & ZHANG XingYingCenter for Space Science Applied Research Chinese Academy of Sciences Beijing China National Satellite Meteorological Center Beijing 《科学通报(英文版)》2010,55(1):84-89
FY-3 satellites are Chinese second-generation polar orbit meteorological satellite series. Ultraviolet Total Ozone Unit (TOU) is one of the main payloads on FY-3 satellite and the first instrument for daily global coverage of total ozone monitoring in China. The main purpose of TOU is to measure the Earth backscatter ultraviolet radiation for retrieving daily global map of atmospheric ozone. TOU will provide the important parameters for environmental monitoring, climate forecasting and global climate changi... 相似文献
963.
YU Huan WANG PuCai ZONG XueMei LI Xin & Lü DaRen LAGEO Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Graduate University of Chinese Academy of Sciences Beijing Beijing Municipal Environmental Protection Bureau Beijing 《科学通报(英文版)》2010,55(3):308-313
The effect of the air quality ensuring measures for the Beijing 2008 Olympic Games in reducing air pollution during the game period is assessed using the tropospheric NO2 column density retrieved from Ozone Monitoring Instrument onboard AURA satellite. The basic method of the assessment is the comparison of the NO2 column densities during the game period with that during the corresponding period of 2005−2007 for the Beijing area, and the comparison among Beijing and neighbouring cities Tianjin and Tangshan, which are of similar situation in air pollution of NO2 in recent years. The images of tropospheric NO2 column densities over Northern China during the Beijing 2008 Olympic Games show the remarkable effect of the air quality ensuring measures in reducing NO2 pollution: the tropospheric NO2 column density in Beijing is much lower than that in Tianjin and Tangshan, while there were very similar values in the three large cities during the same period of the last three years. About 40% reduction in tropospheric NO2 column density over the Beijing area is obtained from the assessment during July to August, 2008, a key period of air quality ensuring measures for the Beijing 2008 Olympic Games. 相似文献
964.
WANG ShanShan LI Qin Lü XueFei LIU Tong ZHANG WeiBo GENG LiNa & DENG YuLin School of Life Science Technology Beijing Institute of Technology Beijing China Analysis Test Center Sh ong Academy of Sciences Jinan 《科学通报(英文版)》2010,55(10):910-914
In the present study,a new enzymatic microreactor is developed by immobilizing trypsin on the matrix-HILIC (hydrophilic interaction chromatography).The influences of different types of buffer solutions (borate,Tris·HCl,and phosphate),their concentrations and pH values on the immobilizing rate and the activity of immobilized trypsin were investigated.The optimal condition for off-line immobilization of trypsin on matix-HILIC was Tris·HCl buffer (20 mmol/L,pH 8.0),and then,under the optimal condition,an enzym... 相似文献
965.
YAO ZhengQuan XIAO GuoQiao & LIANG MeiYan State Key Laboratory of Loess Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China Graduate University of the Chinese Academy of Sciences Beijing Institute of Geology Geophysics Beijing 《科学通报(英文版)》2010,55(9):787-790
Major element concentrations were analyzed on the sediments of a 203.6-m core from the North China Plain near Tianjin. The chemical index of alteration (CIA), Al2O3-(CaO+Na2O)-K2O diagram and elemental ratios, such as Al/K and Ti/Na, were used to reveal information of chemical weathering in the source regions since the late Pliocene. Results show that the fluvial materials in the North China Plain were derived from vast regions, which were in the early Na and Ca removal stage and underwent numerous upper-crustal recycling processes. Proxies of chemical weathering show a decreasing trend, in parallel with the global cooling since the late Pliocene, suggesting a strong role of the global cooing in controlling the continental chemical weathering intensity. 相似文献
966.
ZHENG JianJun ZHANG ZhiYuan HUANG ZuoHua HU ErJiang TANG ChengLong & WANG JinHua State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an China 《科学通报(英文版)》2010,55(9):882-889
The effect of nitrogen dilution on the premixed combustion characteristics and flame structure of laminar premixed methanol-air-nitrogen mixtures are analyzed numerically based on an extended methanol oxidation mechanism. The laminar burning velocities, the mass burning fluxes, the adiabatic flame temperature, the global activation temperature, the Zeldovich number, the effective Lewis number and the laminar flame structure of the methanol-air-nitrogen mixtures are obtained under different nitrogen dilution ratios. Comparison between experiments and numerical simulations show that the extended methanol oxidation mechanism can well reproduce the laminar burning velocities for lean and near stoichiometric methanol-air-nitrogen mixtures. The laminar burning velocities and the mass burning fluxes decrease with the increase of nitrogen dilution ratio and the effect is more obvious for the lean mixture. The effective Lewis number of the mixture increases with the increase of nitrogen dilution ratio, and the diffusive-thermal instability of the flame front is decreased by the nitrogen addition. Nitrogen addition can suppress the hydrodynamic instability of methanol-air-nitrogen flames. The decrease of the mole fraction of OH and H is mainly responsible for the suppressed effect of nitrogen diluent on the chemical reaction in the methanol-air-nitrogen laminar premixed flames, and the NOx and formaldehyde emissions are decreased by the nitrogen addition. 相似文献
967.
研究了如下高阶半线性抛物型方程的Cauchy问题{ut+(-Δ)mu=│u│p-1u,(x,t)∈Rn×R1+ u(x,0)=u0(x),x∈Rn的解的整体存在性,其中m是正整数,p1+2m/n,n≥2。首先将该问题转化为与之等价的积分方程,然后通过引入该问题的一个自相似核构造了一个积分方程,该积分方程的解控制了原问题的等价积分方程的解,最后通过证明构造的积分方程的解有界,从而得到等价积分方程的解有界,因此,当m≥2且初值u0(x)满足u0(x)≤α/(1+x2m/(p-1))时,该问题有整体强解。另外在条件lim|x|→∞ inf│x│2m/(p-1)u0(x)0下,利用弱解的定义和试验函数的紧支性证明了该问题的弱解的负部相对于正部是不能忽略的。 相似文献
968.
三峡水库消落带生态友好型利用途径探索———以基塘工程为例 (三峡地区资源环境生态研究)
总被引:1,自引:0,他引:1
总被引:1,自引:0,他引:1
三峡水库水位的反季节变动给消落带带来了一些不可避免的生态环境问题,同时也为消落带的利用提供了机遇。如何才能既对消落带土地资源进行有效利用,同时又能解决消落带内产生的生态环境问题,这是本文研究的主要目的。本文探讨了基塘工程这一基于三峡水库季节性水位变动和消落带地形特征而设计的湿地生态友好利用途径,并从作物产量和生物多样性改变两个方面对其生态经济效益进行了评价。结果表明,基塘工程具有可观的经济效益,同时基塘工程区域植物种类组成与对照区植物种类组成有明显差别。与对照区相比,基塘工程区拥有较多的水生植物和较少的陆生植物。研究表明,基塘工程是一种适合三峡水库消落带的生态友好型利用途径,有助于改善消落带湿地环境,保护和恢复消落带动植物多样性。
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969.
"近20年来,随着旅游业的快速发展和社会经济人口的压力,以生态环境可持续发展为基础的可持续旅游成为人类关注的热点。三峡是我国最著名的旅游区之一,近年来其旅游生态环境问题日益凸显。科学分析三峡地区脆弱的旅游生态环境及三峡工程引发的生态问题是促进库区可持续旅游发展的前提。调查分析表明,库区目前主要的旅游生态环境问题有:自然灾害、水土流失、蓄水引发的地质灾害、旅游资源消失、水质恶化、库岸消落带“、三废”排放及移民所产生的生态压力等。基于这种旅游生态环境条件及可持续旅游的系统性要求,提出促进库区可持续旅游的建议:1)推进库区旅游生态环境建设;2)创新旅游开发理念;3)开展旅游区旅游生态环境保护的科研工作;4)加强环保教育、转变观念等。"
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970.
结合径向线性组合的定义给出了凸体的Lp-径向线性组合的定义,并探讨出了该组合下凸体的对偶混合体积之间的大小关系,重点研究了凸体的Lp-径向线性组合的平均宽度的相关性质,同时还给出了凸体的Lp-径向线性组合和它的极体的平均宽度的下界。在充分研究凸体的Lp-径向线性组合性质的基础上,得到凸体的Lp-径向线性组合和它的Firey线性组合之间的一些关系式。最后,在这些定理的支撑下,得到了关于凸体的Firey线性组合的平均宽度的下界的一般性结论,若K,L∈K0n实数p≥1,λ,μ≥0,λ+μ=1,则M((λK*+pμL*)+(λK+pμL))≥4,等号成立当且仅当K与L都为单位球时。 相似文献