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1.
Emission inventories of primary particles and pollutant gases for China   总被引:12,自引:0,他引:12  
Detailed high-resolution emission inventories of primary particles(PM2.5,BC and OC) and pollutant gases(SO2,NOx,NH3,CO and VOCs) for China in 2007 were constructed on the basis of the latest fuel consumption data,mostly at the county level,and from socio-economic statistics and data on fossil and biomass fuels obtained from government agencies.New emission factors reflecting local features were also used.The calculated emissions were 13.212 Mt PM2.5,1.4 Mt BC,2.946 Mt OC,31.584 Mt SO2,23.248 Mt NOx,16.017 Mt NH3,164.856 Mt CO and 35.464 Mt VOCs.The national and regional emissions were gridded with 0.5°× 0.5° resolution for use in air quality models.Larger emissions were found in eastern and central China than in western China.The emissions estimated here are roughly equal to those obtained in previous studies,but with different contributions from because of seasonal changes in residential heating and biomass combustion.Finally,uncertainties in inventories were analyzed.  相似文献   
2.
本文详述智能型全固态100WFM发射机研制中的技术问题,总结了研制过程中获得的一些实际经验,并就一些技术难点提出了自己的解决方法。  相似文献   
3.
单分散苯乙烯-马来酸酐共聚物微球增长方式探究   总被引:1,自引:1,他引:0  
以丁酸乙酯为溶剂,AIBN为引发剂,采用自稳定沉淀聚合法于80℃下制备了单分散苯乙烯-马来酸酐(St-MAH)共聚物微球。对反应过程中不同反应时间的单体转化率、共聚物分子量、微球形貌及粒径进行了研究。结果表明,St-MAH共聚物微球粒径的3次方与转化率成直线关系,说明共聚物微球的聚合反应属于活性增长机理;同时提出自稳定沉淀聚合体系制备单分散St-MAH共聚物微球成核过程为AIBN在溶剂中引发苯乙烯和马来酸酐共聚生成寡居物,当寡居物链达到临界长度时从溶剂中沉淀出来,沉淀出来的寡聚物链相互缠绕形成球核;成核后单个微球所含St-MAH共聚物分子链数与时间的关系和转化率、微球粒径与时间的关系趋势大体一致,证实了自稳定沉淀聚合法制备St-MAH共聚物微球的增长主要是溶剂中形成的寡居物沉积于微球表面而实现的。  相似文献   
4.
该文考虑具有时变块对角参数不确定性的线性连续系统的鲁棒H∞滤波问题,即设计线性状态估计器,使得对所有可允的时变块对角参数扰动.估计系统二次稳定且估计误差满足预先给定的H∞干扰衰减的约束.基于关于干扰衰减二次稳定的概念,将一个不确定系统的鲁棒H∞滤波问题转化为一个标准的确定性系统的H∞滤波问题。匿文利用Riccati代数方程方法解决了上述问题,并导出了状态估计器存在的充分必要条件及合乎要求的估计器的表达式。  相似文献   
5.
采用密度泛函B3LYP/6—311G^**和高级电子相关耦合簇CCSD(T)/6-311G^**。方法计算并研究了SiH3与O2(^3∑g)反应的机理,全参数优化了反应势能面上各驻点的几何构型,并用频率分析方法和内禀反应坐标(IRC)进行了计算,对过渡态进行了验证.结果表明:SiH3+O2(^3∑g)反应可经多条路径和多个步骤,经缔合、氢转移和离解得到SiH3O2,SiH2O2+H,SiH2O+OH,SiH3O+O,SiHO2+H2等产物.  相似文献   
6.
As an important tool for heuristic design of NP-hard problems, backbone analysis has become a hot spot in theoretical computer science in recent years. Due to the difficulty in the research on computa- tional complexity of the backbone, many researchers analyzed the backbone by statistic ways. Aiming to increase the backbone size which is usually very small by the existing methods, the unique optimal solution instance construction (UOSIC) is proposed for the graph bi-partitioning problem (GBP). Also, we prove by using the UOSIC that it is NP-hard to obtain the backbone, i.e. no algorithm exists to obtain the backbone of a GBP in polynomial time under the assumption that P ≠ NP. Our work expands the research area of computational complexity of the backbone. And the UOSIC provides a new way for heuristic design of NP-hard problems.  相似文献   
7.
Wei  GuoLiang  Cui  BaoShan  Yang  ZhiFeng  Bai  JunHong  Wang  Juan  Hu  Bo 《科学通报(英文版)》2007,52(2):262-272

Land use changes of river segment ecosystems from the Lancang River and Yuanjiang River were studied from 1985 to 2000 in order to compare their changes of service values and analyze the driving mechanisms based on eco-economic and GIS methods. Results showed that forest areas in both the river segment ecosystems were reduced. The reduced forest in the Lancang River (LR) segment ecosystem was mostly transformed into glebe with the conversion rate of 56.0%, while the reduced forest in the Yuanjiang River (YR) segment ecosystem was mostly transformed into residence land with the conversion rate of 42.5%. Both change amount and change rate of areas of each land use type in the LR segment ecosystem were much larger than those in the YR segment ecosystem. The total service value of the LR segment ecosystem was decreased with the change rate of 15.3%, while that of YR segment ecosystem was increased with the change rate of 0.6%. Manwan Hydropower development was the major anthropogenic driving factor which led to the change of service value of the LR segment ecosystem with the contribution rate of 93%. Agricultural activities were the most important driving factors in the YR segment ecosystem with the contribution rate of 59%. The loss of value of Sediment transportation service resulting from Manwan Hydropower Project construction should take responsibility for the significant decrease of service value of waters, even for the whole LR segment ecosystem. The ecosystem service coefficients of forest and grassland in the study area were much higher than the average level in China, so were the ratios of indirect value to direct value of both the river segment ecosystems. Under the impacts of human activities, the capacity of river ecosystem for providing products was enhanced, while it was weakened to maintain natural ecosystem health.

  相似文献   
8.
Wang  Juan  Cui  BaoShan  Liu  ShiLiang  Dong  ShiKui  Wei  GuoLiang  Liu  Jie 《科学通报(英文版)》2007,52(2):180-191

Based on the land use (LU) (in 1985 and 2000) and road networks (RN) data in the Longitudinal Range-Gorge Region (LRGR), ecosystem services value (ESV) loss under the disturbance of road networks was estimated by using landscape degradation index (LDI) to clarify the effects of human activities on ecosystem service function (ESF). Results show that the ESV decreased more than 65×108 Yuan (RMB) due to the transformation of ecosystems in the study area during the past 16 years. The ecosystems influenced by road networks of different grades account for 5.4% of the total land in the study area. The ecosystems lost their ESV of 1900×108 Yuan (RMB) by the disturbance of RN. The effect of RN on the ESV decreased exponentially. The forecast shows that ESV will be decreased 1.2%/a on average in 2010 and 2020 due to RN projects. The effect of ecosystem structure change on ESV was complex and nonlinear. The disturbance of RN, one of the human activities influencing ESF is considered, further study and new method should be developed to accurately estimate the loss of ESV and the ecosystem function.

  相似文献   
9.
Organometallics are a family of useful organic chemicals because they play important roles in organic synthesis as reagents and as catalysts.They can be classified according to the number of metals they contain.Bimetallic compounds are important organometallics and they are either homobimetallic or heterobimetallic depending on whether the two metals are the same or different.In this paper,we focus on homobimetallic compounds.Homobimetallic compounds are generally used as dianions to react with electrophiles in organic synthesis.Recently,homobimetallics have also been used as catalysts in organic reactions such as in asymmetric reactions.  相似文献   
10.
The spin-forbidden reaction 1HNO(^1A+OH^-→3NO^-(^3∑^-)+H2O has been extensively explored using vari- ous CASSCF active spaces with MP2 corrections in several basis sets. Natural bond orbital (NBO) analysis, together with the NBO energetic (deletion) analysis, indicates that the two isomers have nearly equal total energy and could compete with each other in the title reaction. More significantly, the singlet/triplet surface crossing regions have been examined and the spin-orbit coupling (SOC) and energetics have been computed. The computational results indicate that the SOC is very large at the crossing point T1/S0 trans (ca. 40.9 cm^-1). Moreover, the T1/S0 trans has a low energy of 10.67 kcal/mol relative to that of trans-So. Therefore, the surface crossing to the triplet state seems much more efficient at the T1/S0 trans region along the minimum energy path (MEP), However, The values of single (P1^ISC) and double (P2^ISC) passes estimated at T1/S0 trans show that the ISC occurs with a little probability.  相似文献   
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