检索结果-南通市图书馆

Comparison of temporal and Spatial Characteristics of Ozone Pollution at Ground Level in the Eastern china

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Population,Resources and Environment 2006年第3期4卷 51-57页

作者： Liu Houfeng1,2.1. Shandong normal university, {2. 2.0014, china 2. Chinese Research Academe of Environmental Sciences, Beijing 100012. china Shandong normal university Jinan 250014 China Chinese Research Academe of Environmental Sciences Beijing 100012 China

Monitoring data from ozone（O3） automatic stations in three typical cities with different climatic areas in the southern and northern parts of eastern china are used to analyze temporal and spatial characteristics of ozone pollution at ground level. The results show that ozone pollution level has distinct regional differences and the concentration in the suburbs is higher than that in the urban areas. The seasonal variation of ozone concentration in different climatic areas is greatly affected by the variation of precipitation. Ozone concentration in Shenyang and Beijing , in the temperate zone, has one perennial peak concentration, occurring in early summer, May or June. Ozone concentration in Guangzhou, in sub-tropical zone, has two peak values year round. The highest values occur in October and the secondary high value in June. The ozone season in the south is longer than that in the north. The annual average daily peak value of ozone concentrations in different climates usually occur around 3 pm. The diurnal variation range of ozone concentration declines with the increase of latitude. Ozone concentration does not elevate with the increase of traffic flow. Ozone concentration in Guangzhou has a distinct reverse relation to CO and NOx. This complicated non-linearity indicates that the equilibrium of ozone photochemical reaction has regional differences. Exceeding the rate of Beijing＇s lh ozone concentration is higher than that of Guangzhou, whereas the average 8h ozone level is lower than that of Guangzhou, indicating that areas in low latitude are more easily affected by moderate ozone concentrations and longer exposure. Thus, china should work out standards for 8h ozone concentration.

关键词： ozone temporal and spatial characteristics 8h concentrations weekly variation

Density functional study on enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2006年第4期49卷 296-307页

作者： LI Ming1, ZHENG Wenxu2.& TIAN Anmin2.1. Department of Chemistry, Southwest-china normal {2., Chongqing 400715, china 2. Department of Chemistry, Sichuan {2., Chengdu 610064, china 1. Department of Chemistry Southwest-China Normal University Chongqing 400715 China 2. Department of Chemistry Sichuan University Chengdu 610064 China

The enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine is discussed by the density functional theory (DFT) method. The main intermediates and transition states for this reaction are optimized completely at the B3LYP/6-31g(d) level, and the transition states are verified by vibrational modes. As shown, the chirality-controlled steps for this re- action are the hydride transfer from borane to carbonyl carbon and oxime carbon of keto oxime ether, and the chirality for the reduced products is determined in these two reaction steps. In all examined reaction paths, the first hydride is transferred via a six-membered ring and the second hydride via a five-membered ring or a four-membered ring.

关键词： keto oxime ether, oxazaborolidine, enantioselective reduction, DFT.

Diffusion and Oxidation Wear of PCBN Tool based on Thermodynamics

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of Technology(Materials Science) 2010年第2期25卷 265-271页

作者：邵芳 Binzhou Vacational College School of Mechanical Engineering Shandong University

The rules of diffusion wear and oxidation wear for PCBN cutting tools were analyzed based on thermodynamics theory. Dissolution concentrations in typical normal workpice materials of PCBN tool material at different temperature were then calculated. Diffusion reaction rules in high temperature were developed and analyzed using the Gibbs free energy criterion. The machining tests were conducted using the PCBN tools at different cutting speeds of 50, 95,100 and 180 m/min, feed of 0.1, 0.2.and depth of cut of 0.1, 0.8, 1, and 1.5 mm respectively on a PUMA300LM numerically-controlled lathe. It was found that the theoretical results were uniform with the experimental data, and the results will provide useful references for tool material design and selection.

关键词： thermodynamics PCBN tool diffusion wear oxidation wear

Fuzzy controllers based on some fuzzy implication operators and their response functions

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2004年第1期14卷 16-21页

作者： LI Hongxing 1*, YOU Fei 1 and PENG Jiayin 2.1. Department of Mathematics, Beijing normal university, Beijing 100875,{2. 2. Department of Mathematics, Neijiang Teacher's College, Neijiang 641112.{2.) Beijing normal Univ Dept Math Beijing 100875 Peoples R China

The fuzzy controllers constructed by 2. fuzzy implication operators based on CRI algorithm and their response functions are discussed. The conclusions show that the fuzzy controllers constructed by 9 fuzzy implication operators are universal approximators to continuous functions and can be used in practical fuzzy control systems. And these 9 fuzzy implication operators except for Einstein operator intersection are all the adjoint pairs of some fuzzy implication operators. Besides, there are 3 other fuzzy controllers formed by fuzzy implication operators being regarded approximately as fitted functions.

关键词： fuzzy implication operators CRI algorithm fuzzy controllers response functions universal approximators

Exploration of Science Parks

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Population,Resources and Environment 2005年第1期3卷 55-59页

作者： Xiong Huibing & Sun Nengli 1 2.1. Huazhong Agricultural university, Wuhan Hubei 430079, china 2. Shandong {2. university, jinan Shandong 2.0014, china Huazhong Agricultural university Wuhan Hubei 430079 China Shandong normal university Jinan Shandong 250014 China

Science parks have developed greatly in the world, whereas empirical researches have showed that science parks based on linear model cannot guarantee the creation of innovation. Hi-tech innovation is derived from flow and management of information. The commercial and social interactions between in-parks and off-park firms and research institutions act as the key determinant for innovation. Industrial clustering is the rational choice for further developing Chinese science parks and solving some problems such as the lack of clear major industries and strong innovation sense, etc.

关键词： science parks hi-tech industry industrial clusters

The kink-soliton and antikink-soliton in quasi-one-dimensional nonlinear monoatomic lattice

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2005年第2期48卷 150-157页

作者： XU Quan1 & TIAN Qiang2.1. Scientific and Technological Office, Daqing Teacher College, Daqing 163712. china 2. Department of Physics , Beijing normal {2., Beijing 100875, china Scientific and Technological Office Daqing Teacher College Daqing 163712 China Department of Physics Beijing Normal University Beijing 100875 China

The quasi-one-dimensional nonlinear monoatomic lattice is analyzed. The kink-soliton and antikink-soliton are presented. When the interaction of the lattice is strong in the x-direction and weak in the y-direction, the two-dimensional (2.) lattice changes to a quasi-one-dimensional lattice. Taking nearest-neighbor interaction into account, the vibration equation can be transformed into the KPI, KPII and MKP equation. Considering the cubic nonlinear potential of the vibration in the lattice, the kink-soliton solution is presented. Considering the quartic nonlinear potential and the cubic interaction potential, the kink-soliton and antikink-soliton solutions are presented.

关键词： two-dimensional nonlinear lattice, quasi-one-dimensional nonlinear lattice, kink-soliton, antikink-soliton.

K-uniformly rotund spaces and k-uniformly smooth spaces

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第2期43卷 92-95页

作者： Suyalatu 1 and WU Congxin 2.1. Department of Mathematics,Inner Mongolia normal university, Huhhot 01002.,{2. 2. Department of Mathematics, Harbin Institute of Technology, Harbin 150006,{2. Department of Mathematics Inner Mongolia Normal University Huhhot China Department of Mathematics Harbin Institute of Technology Harbin China

The conception of k_uniform smoothness (KUS) is introduced. It is the extension of the conception of uniform smoothness. It is proved that the k_uniform smoothness and Sullivan’s K_uniform rotundity (KUR) are the daul notions. X+* is a KUR space if and only if X is a KUS space, X+* is a KUS space if and only if X is a KUR space. If X is a KUS space, then X is a (K+1)US space. It is also proved that the KUS space includes the Nan’s k_strongly smooth space.

关键词： K_uniform smoothness K_uniform convexity.

The optical near-field speckles and their first order statistics on the basis of the integral equations of electromagnetic field

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2004年第3期47卷 365-380页

作者： CHENG Chuanfu1, 2. SONG Hongsheng2. LIU Chunxiang2. REN Xiaorong2. ZHANG Ningyu3, TENG Shuyun1 & XU Zhizhan1 1. Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P. O. Box 800-2.1, Shanghai 2.1800, china 2. Department of Physics, Shandong normal {2., jinan 2.0014, china 3. Shandong Institute of Architecture and Engineering, jinan 2.0014, china 1. Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences P. O. Box 800-211 201800 Shanghai China 2. Department of Physics Shandong Normal University 250014 Jinan China 3. Shandong Institute of Architecture and Engineering 250014 Jinan China

From Helmholtz equation of the harmonic electromagnetic waves, the integral equations of the light field at the medium boundaries are obtained by use of the Green's theorem and are discretized into linear equation set with the values of the light field and its derivative as the unknowns. On solving the linear equation set, we realize the rigorous computations of the light fields at the boundaries. Then the intensities of the light waves scattered by the random self-affine fractal surfaces in the optical near-field are calculated, and the propagation characteristics, the evolutions of the contrast and the intensity probability density function of the near-field speckles are studied in detail. The near-field speckles are much different from the conventional speckles in the diffraction regions and in the imaging systems. There are obvious local fluctuations in the intensity distributions of the near-field speckles and such fluctuations disappear after propagating a distance of one wavelength from the medium surfaces. For the random surfaces with smaller lateral correlation lengths, the speckle contrasts approach the saturation values and the speckle fields approach Gaussian distribution within the near-field, while for the random surfaces with larger lateral correlation lengths, such evolutions become comparatively slow.

关键词： speckle, near-field optics, first order statistics, Green's function.

Existence of the solutions and the attractors for the large-scale atmospheric equations

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2006年第6期49卷 650-660页

作者： HUANG Haiyang1 & GUO Boling2.1. Department of Mathematics, Beijing normal university, Beijing 100875,{2. 2. Institute of Applied Physics and Computational Mathematics, Beijing 100080,{2. 1. Department of Mathematics Beijing Normal University Beijing 100875 China 2. Institute of Applied Physics and Computational Mathematics Beijing 100080 China

In this paper, firstly, the proper function space is chosen, and the proper expression of the operators is introduced such that the complex large-scale atmospheric motion equations can be described by a simple and abstract equation, by which the definition of the weak solution of the atmospheric equations is made. Secondly, the existence of the weak solution for the atmospheric equations and the steady state equations is proved by using the Galerkin method. The existence of the non-empty global attractors for the atmospheric equations in the sense of the Chepyzhov-Vishik’s definition is obtained by constructing a trajectory attractor set of the atmospheric motion equations. The result obtained here is the foundation for studying the topological structure and the dynamical behavior of the atmosphere attractors. Moreover, the methods used here are also valid for studying the other atmospheric motion models.

关键词： atmosphere equations, weak solution, trajectory attractor, global attractor, equilibrium.