检索结果-南通市图书馆

Weak Morrey spaces and strong solutions to the Navier-Stokes equations

在线全文

学校读者我要写书评

暂无评论

Science China mathematics 2007年第10期50卷 1401-1417页

作者： Chang-xing MIAO~(1+) Bao-quan YUAN~2.~1 Institute of Applied Physics and Computational mathematics,P.O.Box 8009,Beijing 100088,China ~2.college of mathematics and informatics,{2.,jiaozuo 454000,China 1. Institute of Applied Physics and Computational mathematics P.O. Box 8009 Beijing 100088 China 2. college of mathematics and {2. Henan Polytechnic University Jiaozuo 454000 China

We consider the Cauchy problem of Navier-Stokes equations in weak Morrey *** first define a class of weak Morrey type spaces M_(p,λ)~*(R^n)on the basis of Lorentz space L_(p,∞)=L_p~*(R^n) (in particular,M_(?)~*(R^n)=L_(p,∞),if p>1),and study some fundamental properties of them;Second, we prove that the heat operator U(t)= e^(tΔ)and Calderón-Zygmund singular integral operators are bounded linear operators on weak Morrey spaces,and establish the bilinear estimate in weak Morrey ***,by means of Kato's method and the contraction mapping principle,we prove that the Cauchy problem of Navier-Stokes equations in weak Morrey spaces M_(p,λ)~*(R^n)(1

关键词： Navier-Stokes equations, weak Morrey spaces, Lorentz spaces, Cauchy problem,time-global well-posedness, self-similar solutions

Extraction of vegetation fraction information from CBERS images based on VBSI vegetation index in Kaixian county

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2011年第S3期21卷 712-716页

作者： GAO Zhi-fang1, NIU Hai-peng1, LIU Jin-ping2.1. college of Surveying and Land Information Engineering, henan polytechnic university, {2., China 2. college of Geographic Sciences, Chongqing Normal university, Chongqing 400047, China [a] college of Surveying and Land Information Engineering Henan Polytechnic University Jiaozuo 454000 China [b] college of Geographic Sciences Chongqing Normal University Chongqing 400047 China

Based on the mixed pixel model, the vegetation fraction of Kaixian county, China, was extracted with three free CBERS images. VBSI vegetation index suitable for CBERS images constructed with FCD (forest canopy density) model principle was put forward by ITTO (International Tropical Timber Organization) was used, considering the underestimation of vegetation fraction using NDVI in low mountain-hill region influenced by soils and shadows. And vegetation fraction was divided into five categories from low to high in order to study the special variation of vegetation cover. The results show that the vegetation cover of the region is overall good, with an average of 50%. The area of vegetation fraction below 30% accounts for 11.7% of the entire studied area, mainly concentrates in central eastern Kaixian county, where is the major development zone of cities and towns; that between 30% and 60% accounts for 62.; and that higher than 60% accounts for 2.%, and mostly locates in northern middle-mountain area.

关键词： VBSI vegetation index mixed pixel model FCD model CBERS

Suitability evaluation for land reclamation in mining area:A case study of Gaoqiao bauxite mine

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2011年第S3期21卷 506-515页

作者： WANG Shi-dong1, 2. LIU Chang-hua2. ZHANG He-bing2.1. college of Resources Science and Technology, Beijing Normal university, Beijing 100875, China 2. School of Surveying and Land Information Engineering, {2., jiaozuo 454000, China [a] college of Resources Science and Technology Beijing Normal University Beijing 100875 China [b] School of Surveying and Land Information Engineering Henan Polytechnic University Jiaozuo 454000 China

Suitability evaluation plays an important role in land reclamation because the choice of evaluation methods affects the accuracy and objectivity of the suitability evaluation results. Furthermore, it influences the decision-making related to land reclamation. An improved method, which is called limit comprehensive conditions method, was developed after different suitability evaluation methods were studied. Based on this method, the reclaimed land of the Gaoqiao bauxite mining area was evaluated. The Gaoqiao mining area was divided into seven evaluation units that were evaluated respectively by selecting evaluation factors and establishing grade standards. The results show that the proposed method is more applicable and easier to handle. Moreover, its evaluation results are more scientific compared with the traditional evaluation methods. The improved method can be beneficial to the rapid monitoring and the effective management of reclaimed land in the opencast mine area.

关键词： mining area land reclamation suitability evaluation Gaoqiao bauxite mine

Relationship between surface subsidence factor and mining depth of strip pillar mining

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2011年第S3期21卷 594-598页

作者： GUO Wen-bing1, 2. HOU Quan-lin 1, ZOU You-feng2.1. college of Earth Science, Graduate university of Chinese Academy of Sciences, Beijing 100049, China 2. School of Energy Science and Engineering, {2., jiaozuo 454000, China Chinese Acad Sci Coll Earth Sci Grad Univ Beijing 100049 Peoples R China henan Polytech Univ Sch Energy Sci & Engn Jiaozuo 454000 Peoples R China

Strip pillar mining is one of the most important technical measures to control mining subsidence in China. Mining depth is one of the most important factors that can affect the mining subsidence in strip pillar mining. Six numerical simulation models were set up to simulate the surface subsidence of strip pillar mining in different mining depths. The mining depth in these six models ranges from 300 to 800 m. The simulated results were compared and analyzed. The formula was established based on the simulated results. It demonstrated that the subsidence of strip pillar mining method is related to mining depth. While the other conditions are the same, the subsidence of strip pillar mining increases with the increase of mining depth by logarithmic relationship.

关键词： subsidence factor strip pillar mining mining depth numerical simulation

Electronic Structure and Thermoelectric Properties of Ca_3Co_4O_9

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) 2006年第1期21卷 13-15页

作者：闵新民 Department of Applied Chemistry Wuhan University of TechnologyWuhan 430070China

The relation among electronic structure, chemical bond and thermoelectric property of Ca3 Co4 O9 was studied using density function and discrete variation method （DFT-DVM）. The gap between the highest valence band （HVB） and the lowest conduction band （LCB） shows a semiconducting property. Ca3 Co4 O9 consists of CoO2.and Ca2.CoO3 two layers. The HVB and LCB near Fermi level are only mainly from O（ 2.） 2. and Co （2. 3d in Ca2.CoO3 layer. Therefore, the semiconducting or thermoelectric property of Ca3 Co4 O9 should be mainly from Ca2.CoO3 layer, but it seems to have no direct relation to the CoO2.layer, which is consistent with that binary oxides hardly have a thermoelectric property, but trinary oxide compounds have quite a good thermoelectric property. The covalent and ionic bonds of Ca2.CoO3 layer are both weaker than those of CoO2.layer. Ca plays the role of connections between CoO2.and Ca2.CoO3 layers in Ca3 Co4 O9, decrease the ionic and covalent bond strength, and improve the thermoelectric property.

关键词： cobaltite electronic structure chemical bond thermoelectric property

Vision navigation algorithm for mine agent based on quaternion

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2011年第S3期21卷 610-615页

作者： LI Ke-zhao1, 4, LEI Wei-wei1, 2. GUO Zeng-zhang1, 2. WU Li-xin3, ZHANG Qin4 1. School of Survey and Land Information Engineering, henan polytechnic university, jiaozuo 454003, China 2. Key Laboratory of Mine Spatial Information Technologies of State Bureau of Surveying and Mapping, henan polytechnic university, jiaozuo 454003, China 3. college of Resources and Civil Engineering, Northeastern university, Shenyang 110819, China 4. college of Geology Engineering and Geomatics, Chang’an university, Xi’an 710054, China [a] School of Survey and Land Information Engineering Henan Polytechnic University Jiaozuo 454003 China [b] Key Laboratory of Mine Spatial Information Technologies of State Bureau of Surveying and Mapping Henan Polytechnic University Jiaozuo 454003 China [c] college of Resources and Civil Engineering Northeastern University Shenyang 110819 China [d] college of Geology Engineering and Geomatics Chang'an University Xi'an 710054 China

Autonomous relative navigation is the key technology in mining or rescuing. On the basis of mine requirement and the theories of machine vision, an autonomous relative navigation algorithm for mine agent based on quaternion was proposed. In rotation transformation, this algorithm was represented by using quaternion. Because the Jacobi matrix of this method is lower than that of Hall algorithm, the calculation efficiency is improved by using this algorithm. The results of these experiments show that the computation burden of this algorithm based on quaternion is about half that of Hall algorithm. This algorithm based on quaternion is improved as a valid way to solve the problem of mine real-time navigation.

关键词： quaternion mine agent vision navigation

Digital close-range photogrammetric application to small-scale physical simulation experiment

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2011年第S3期21卷 681-685页

作者： LI Chun-yi1, CUI Xi-min2. YU Yi-ju3 1. School of Surveying and Landing Information Engineering, henan polytechnic university, jiaozuo 454003, China 2. {2. of Geoscience and Surveying Engineering, China university of Mining and Technology, Beijing 100083, China 3. Surveying and Mapping Press, Beijing 100045, China [a] School of Surveying and Landing Information Engineering Henan Polytechnic University Jiaozuo 454003 China [b] college of Geoscience and Surveying Engineering China University of Mining and Technology Beijing 100083 China [c] Surveying and Mapping Press Beijing 100045 China

In order to research the possibility of digital close-range photogrammetric surveying in small scale physical simulation experiment, physical model coinciding with engineering practice was constructed based on similar theory. The datum processing method and surveying precision of digital close-range photogrammetric were analyzed. And the function relationship between overburden subsidence factor qr and the ratio z/H of stratum horizon z and mining depth H was researched. The results show that surveying points position mean error along horizontal direction is ±0.131 mm and vertical direction is ±0.192.mm. Therefore, multi-taking station cross direction digital close-range photogrammetric can completely satisfy the precision need of physical simulation experiment. And the empirical formula can be utilized to represent evolution law of stratum subsidence factor.

关键词： close-range photogrammetric physical simulation light-rays adjustment surveying precision subsidence factor

Expansive Behaviors of Self-stressing Concrete under Different Restraining Conditions

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) 2011年第4期26卷 780-785页

作者：常旭 college of Civil Engineering Henan Polytechnic University

The expansive behaviors of the expensive concrete under different restraining conditions were systemically studied. The experimental results indicate that expansive deformation obviously increases before 10 days and tends to be constant after 2. days regardless of the restraining conditions. The mixture ratio of expansive cement and restraining conditions are the main factors affecting expansive deformation. Self-stress can be obtained when the expansive deformation is restrained. The higher self-stress could be obtained when the expensive concrete is restrained by steel tube. For specimens under steel tube restraining, the wall thickness and the length of the steel tube have important influence on self-stress. Both the radial self-stress and axial self-stress in concrete core increase when wall thickness or length of the steel tube increases.

关键词： self-stress expansive concrete restraining condition

Site design with regard to climatic elements

在线全文

学校读者我要写书评

暂无评论

Site design with regard to climatic elements