检索结果-南通市图书馆

NUMERICAL SIMULATION OF CAVITATION FLOW UNDER HIGH PRESSURE AND TEMPERATURE

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2011年第3期23卷 289-294页

作者： ZHAO Wei-guo ZHANG Ling-xin SHAO Xue-ming department of Mechanics Zhejiang University Hangzhou 310027 China State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China

The numerical simulation of cavitation flow on a 2D NACA0015 hydrofoil under high pressure and temperature is performed. The Singhal＇s cavitation model is adopted combined with an improved RNG k-ε turbulence model to study the cavitation flow. The thermal effect in the cavitation flow is taken into account by introducing the energy equation with a source term based on the latent heat transfer. The code is validated by a case of a hydrofoil under two different temperatures in a comparison between the simulation and the experiment. Computational results show that the latent heat of vaporization has a significant impact on the cavitation process in the high temperature state, and the cavity in the high temperature state is thinner and shorter than that in a normal state with the same cavitation number, due to the fact that the heat absorption in the cavitation area reduces the local temperature and the saturated vapor pressure. This numerical study provides some guidance for the design of machineries in the High Pressure and Temperature （HPT） state.

关键词： cavitation NACA0015 thermodynamic CFD high pressure and temperature

ON F-z-SUPPLEMENTED SUBGROUPS OF FINITE GROUPS

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2011年第1期31卷 22-28页

作者：郭文彬唐娜李保军 department of mathematics University of Science and Technology of China department of mathematics Xuzhou Normal University department of mathematics Huaiyin Teachers College School of mathematics Chengdu University of Information Technology

A subgroup H of a group G is called F-z-supplemented in G if there exists a subgroup K of G, such that G = HK and H∩K≤ Z∞F（G）, where Z∞F（G） is the F-hypercenter of G. We obtain some results about the F-z-suppl... 详细信息

关键词： Finite groups local formations F-z-supplemented subgroups supersoluble groups p-nilpotent groups

Histidine enhances carbamazepine action against seizures and improves spatial memory deficits induced by chronic transauricular kindling in rats

在线全文

学校读者我要写书评

暂无评论

Acta Pharmacologica Sinica 2005年第11期26卷 1297-1302页

作者： Qing LI~(2,3), Chun-lei JIN~2, Li-sha XU~2, Zheng-bin ZHU-GE~2, Li-xia YANG~2, Lu-ying LIU~2, Zhong CHEN~(2,4) ~2 department of Pharmacology, Zhejiang University, hangzhou 310031, china ~3 department of Physiology, Zhejiang Medieal college, hangzhou 310053, china department of Pharmacology Zhejiang University Hangzhou China department of Physiology Zhejiang Medical College Hangzhou China

Aim: To investigate whether histidine can enhance the anticonvulsant efficacy of carbamazepine (CBZ) and simultaneously improve the spatial memory impairment induced by transauricular kindled seizures in Sprague-Dawley rats. Methods: Chronic transauricular kindling was induced by repeated application of initially subconvulsive electrical stimulation through ear-clip electrodes once every 24 h until the occurrence of 3 consecutive clonic-tonic seizures. An 8-arm radial maze (4 arms baited) was used to measure spatial memory, and histamine and γ-amino-butyric acid levels were measured by high performance liquid chromatography (HPLC). Results: Chronic transauricular kindling produced a significant impairment of spatial memory and a marked decrease in histamine content in the hypothalamus, the brainstem, and the hippocampus. Injection of histidine (1000 mg/kg or 1500 mg/kg, ip) significantly inhibited transauricular kindled seizures. Injection of histidine at lower doses (200 mg/kg or 500 mg/kg, ip) had no appreciable anticonvulsant effect when administered alone, whereas it significantly potentiated the protective effects of CBZ against kindled seizures. CBZ had no ameliorative effect on memory deficit, but, in contrast, histidine (200 mg/kg or 500 mg/kg, ip) alone or co-administered with CBZ significantly ameliorated the memory deficits induced by the seizures. Conclusion: Chronic transauricular kindling is a very useful animal model for evaluating memory deficits associated with epilepsy, and histidine has both a potentiate effect on the anticonvulsant efficacy of CBZ and an ameliorative effect on the spatial memory deficits induced in this model. Histidine at a specific dosage range might serve as a beneficial adjuvant for the clinical treatment of epilepsy, especially when accompanied by impaired spatial memory.

关键词： histidine carbamazepine memory disorders transauricular kindled seizures epilepsy

Goodness-of-fit tests for vector autoregressive models in time series

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china mathematics 2010年第7期53卷 187-202页

作者： WU JianHong 1,& ZHU LiXing 21 college of Statistics and mathematics,Zhejiang Gongshang University,hangzhou 310018,china 2 department of mathematics,Hong Kong Baptist University,Hong Kong,china college of Statistics and mathematics Zhejiang Gongshang University Hangzhou China department of mathematics Hong Kong Baptist University Hong Kong China

The paper proposes and studies some diagnostic tools for checking the goodness-of-fit of general parametric vector autoregressive models in time series. The resulted tests are asymptotically chi-squared under the null hypothesis and can detect the alternatives converging to the null at a parametric rate. The tests involve weight functions,which provides us with the flexibility to choose scores for enhancing power performance,especially under directional alternatives. When the alternatives are not directional,we construct asymptotically distribution-free maximin tests for a large class of alternatives. A possibility to construct score-based omnibus tests is discussed when the alternative is saturated. The power performance is also investigated. In addition,when the sample size is small,a nonparametric Monte Carlo test approach for dependent data is proposed to improve the performance of the tests. The algorithm is easy to implement. Simulation studies and real applications are carried out for illustration.

关键词： goodness-of-fit test maximin test nonparametric Monte Carlo test score type test time series vector autoregressive model

A CLASS OF NONLINEAR SINGULARLY PERTURBED INITIAL BOUNDARY VALUE PROBLEMS FOR REACTION DIFFUSION EQUATIONS WITH BOUNDARY PERTURBATION

在线全文

学校读者我要写书评

暂无评论

Applied mathematics(A Journal of Chinese Universities) 2007年第2期22卷 201-206页

作者： Mo Jiaqi department of mathematics, Anhui normal University, Wuhu 241000, china department of mathematics, Huzhou Teachers college, Huzhou 313000, china Division of Computational Science, E-Institutes of Shanghai Universities at SJTU, Shanghai 200240, china. department of mathematics Anhui Normal University Wuhu China department of mathematics Huzhou Teachers College Huzhou China Division of Computational Science E-Institutes of Shanghai Universities at SJTU Shanghai China

A class of nonlinear initial boundary value problems for reaction diffusion equations with boundary perturbation is considered. Under suitable conditions and using the theory of differential inequalities the asymptoti... 详细信息

关键词： nonlinear reaction diffusion singular perturbation boundary perturbation

EQUIVALENT CONDITIONS FOR THE FINITENESS OF GAUGE

在线全文

学校读者我要写书评

暂无评论

Systems Science and Mathematical Sciences 1997年第4期10卷 299-308页

作者： YIN Chuancun(department of mathematics, Qufu normal University, Shandong 273165, china)JIANG Zhaolin(department of mathematics, Linyi Teacher,college, Shandong 276005, china)

Some equivalent conditions for the finiteness of gauge on a class of unboundeddomains in Rd are given.

关键词： Gauge additive functional Brownian motion.

Rose solutions with three petals for planar 4-body problems

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2010年第12期53卷 3085-3094页

作者： DENG ChunHua 1,2 , ZHANG ShiQing 1, & ZHOU Qing 3 1 Yangtze Center of mathematics and college of mathematics, Sichuan University, Chengdu 610064, china 2 Faculty of mathematics and Physics, Huaiyin Institute of Technology, Huai’an 223001, china 3 department of mathematics, East china normal University, Shanghai 200062, china Yangtze Center of mathematics and college of mathematics Sichuan University Chengdu China Faculty of mathematics and Physics Huaiyin Institute of Technology Huai’an China department of mathematics East China Normal University Shanghai China

For planar Newtonian 4-body problems with equal masses, we use variational methods to prove the existence of a non-collision periodic choreography solution such that all bodies move on a rose-type curve with three pet... 详细信息

关键词： 4-body problems with Newtonian potentials rose solutions with three petals winding numbers variational minimization methods

Carbendazim induces a temporary change in soil bacterial community structure

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2009年第12期21卷 1679-1683页

作者： WANG Xiuguo, SONG Min, GAO Chunming, DONG Bin, ZHANG Qun, FANG Hua, YU Yunlong department of Plant Protection, college of Agriculture and Biotechnology, Zhejiang University, hangzhou 310029, china. department of Plant Protection College of Agriculture and Biotechnology Zhejiang University Hangzhou 310029 China

The effect of carbendazim applications on the diversity and structure of a soil bacterial community was studied under field conditions using temperature gradient gel electrophoresis （TGGE） and partial sequence analysis of PCR-amplified 16S rRNA gene. After four successive introductions of carbendazim at a level of 0.94 kg active ingredient （a.i.）/ha, the genetic diversity （expressed as Shannon index, H′） decreased from 1.43 in the control to 1.29 in treated soil. This harmful effect seems to increase with the concentration of carbendazim. The value of H＇ in the soil treated with carbendazim at 4.70 kg a.i./ha was reduced to 1.05 （P ≤ 0.05）. The structure of soil bacterial community was also affected after four repeated applications of carbendazim at levels of 0.94, 1.88 and 4.70 kg a.i./ha, as seen in the relative intensities of the individual band. However, the bacterial community in carbendazim-treated soil recovered to that in the control 360 d after the first treatment. The results indicated that repeated applications of carbendazim could reduce soil microbial diversity and alter the bacterial community structure temporarily.

关键词： carbendazim bacterial diversity temperature gradient gel electrophoresis phylogenetic analysis

Genetic analysis and gene mapping of a new rolled-leaf mutant in rice (Oryza sativa L.)

在线全文

学校读者我要写书评

暂无评论

Science china(Life Sciences) 2009年第9期52卷 885-890页

作者： SHI YongFeng1,2,CHEN Jie1,LIU WenQiang1,HUANG QiNa1,2,SHEN Bo2,LEUNG Hei3 & WU JianLi1 1 Chinese National Center for Rice Improvement/National key Laboratory for Rice Biology,china National Rice Research Institute,hangzhou 310006,china 2 college of Life and Environmental Sciences,hangzhou normal University,hangzhou 310016,china 3 International Rice Research Institute,Metro Manila DAPO Box 7777,Philippines Chinese National Center for Rice Improvement/National key Laboratory for Rice Biology China National Rice Research Institute Hangzhou China college of Life and Environmental Sciences Hangzhou Normal University Hangzhou China International Rice Research Institute Manila Philippines

To understand the development of rice leaf blades,we identified a new rolled-leaf mutant,w32,from indica cultivar IR64 through EMS mutagenesis. The mutant showed a stable rolled-leaf phenotype throughout the life cycle. Two F2 populations were developed by crossing w32 to cultivar IR24 and PA64. Genetic analysis showed that the rolled-leaf phenotype was controlled by a single recessive gene. To determine the location of the gene,bulked segregant analysis was carried out using mutant and wild-type DNA pools and 1846 mutant-type F2 individuals derived from the cross w32/PA64 were genotyped to locate the gene on the short arm of chromosome 7. The rolled-leaf gene,tentatively named rl11(t),is likely a new gene as no other rolled-leaf genes have been identified near the region. By developing new SSR and InDel markers,the gene was delimited to a 52 kb region near the end of the short chromosome arm. Further fine mapping and cloning of the gene are currently underway.

关键词： rice (Oryza sativa L.) chemical mutagenesis molecular marker rolled-leaf gene physical map