检索结果-南通市图书馆

Controlled Fabrication of Cd-Bi Nanoparticles via Sonochemical Method

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2005年第6期21卷 646-649页

作者： CHEN Hong-jie li Sheng li zhi-wei WU zhi-shen ZHANG Ping-yu ZHANG zhi-jun Key Laboratory for Special Functional Materials College of Medical Henan Univerity Kaifeng 475001 P. R. China

A sonochemical method for the direct controlled synthesis of Cd-Bi nanoparticles from a bulk Cd-Bi alloy is introduced. The nanoparticles were found to be monodispersed and the size distribution can be easily controlled by adjusting the ultrasonic power. The formation and the constituent of the as-prepared Cd-Bi nanoparticles were revealed by means of X-ray diffraction, differential thermal analysis and thermogravimetry, transmission electron microscopy, and electron diffraction. It was found that the Cd-Bi eutectic alloy nanoparticles are made of the hexagonal phase of metal cadmium and the rhombohedral phase of metal bismuth. In addition, we also found through tribological tests that the powder has an excellent antiwear property.

关键词： Sonochemistry Nanoalloy Controlling fabrication Tribology

在线全文

学校读者我要写书评

暂无评论

I Love My Motherland

上海翻译 1990年第3期 48-49页

作者： li wei-zhi

1989年12月,徐汇区教育局举行第二届社会力量办学英语演讲竞赛。沪江业余进修学院英语高级口语班学员李维智、高中俊荣获竞赛高级组第一、第三名。兹将李维智的讲稿I loveMy Motherland刊登如下。该讲稿文情并茂,充分表达一个科技工作... 详细信息

1989年12月,徐汇区教育局举行第二届社会力量办学英语演讲竞赛。沪江业余进修学院英语高级口语班学员李维智、高中俊荣获竞赛高级组第一、第三名。兹将李维智的讲稿I loveMy Motherland刊登如下。该讲稿文情并茂,充分表达一个科技工作者对祖国的热爱,值得一读。

关键词：英语演讲社会力量办学进修学院沪江科技工作者 doing mother college speak remember

Heterosis and heterotic patterns of maize germplasm revealed by a multiple-hybrid population under well-watered and drought-stressed conditions

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2022年第9期21卷 2477-2491页

作者： SANG zhi-qin ZHANG Zhan-qin YANG Yu-xin li zhi-wei liU Xiao-gang XU Yun-bi li wei-hua Key Laboratory of Oasis Eco-Agriculture Xinjiang Production and Construction Corps/Agricultural CollegeShihezi UniversityShihezi 832003P.R.China Xinjiang Academy of Agricultural and Reclamation Science Shihezi 832000P.R.China Institute of Crop Sciences Chinese Academy of Agricultural SciencesBeijing 100081P.R.China International Maize and Wheat Improvement Center(CIMMYT) El Batan Texcoco 56130Mexico

Understanding the heterosis in multiple environments between different heterotic groups is of fundamental importance in successful maize breeding. A total of 737 hybrids derived from 41 maize inbreds were evaluated over two years, with the aim of assessing the genetic diversity and their performance between heterotic groups under drought-stressed(DS) and well-watered(WW) treatments. A total of 38 737 SNPs were employed to assess the genetic diversity. The genetic distance(GD) between the parents ranged from 0.05 to 0.74, and the 41 inbreds were classified into five heterotic groups. According to the hybrid performance(high yield and early maturity between heterotic groups), the heterosis and heterotic patterns of Iowa Stiff Stalk Synthetic(BSSS)×Non-Stiff Stalk(NSS), NSS×Sipingtou(SPT) and BSSS×SPT were identified to be useful options in China’s maize breeding. The relative importance of general and specific combining abilities(GCA and SCA) suggests the importance of the additive genetic effects for grain yield traits under the WW treatment, but the non-additive effects under the DS treatment. At least one of the parental lines with drought tolerance and a high GCA effect would be required to achieve the ideal hybrid performance under drought conditions. GD showed a positive correlation with yield and yield heterosis in within-group hybrids over a certain range of GD. The present investigation suggests that the heterosis is due to the combined accumulation of superior genes/alleles in parents and the optimal genetic distance between parents, and that yield heterosis under DS treatment was mainly determined by the non-additive effects.

关键词： maize drought stress heterosis heterotic group heterotic pattern genetic distance

LARGE EDDY SIMULATION OF THE INTERACTION BETWEEN WALL JET AND OFFSET JET

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2011年第5期23卷 544-553页

作者： li zhi-wei HUAI Wen-xin HAN Jie State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan 430072 China

The interaction between a plane wall jet and a parallel offset jet is studied through the Large Eddy Simulation （LES）. In order to compare with the related experimental data, the offset ratio is set to be 1.0 and the Reynolds number Re is 1.0× 104 with respect to the jet height L and the exit velocity U0. The Finite Volume Method （FVM） with orthogonal-mesh （6.17× 106 nodes） is used to discretize governing equations. The large eddies are obtained directly, while the small eddies are simulated by using the Dynamic Smagorinsky-lily Model （DSLM） and the Dynamic Kinetic energy Subgrid-scale Model （DKSM）. Comparisons between computational results and experimental data show that the DKSM is especially effective in predicting the mean stream-wise velocity, the half-width of the velocity and the decay of the maximum velocity. The variations of the mean stream-wise velocity and the turbulent intensity at several positions are also obtained, and their distributions agree well with the measurements. The further analysis of dilute characteristics focuses on the tracer concentration, such as the distributions of the concentration （i.e., C / C0 or C / C,,）, the boundary layer thickness 6c and the half-width of the concentration b., the decay of the maximum concentration （ C / Co） along the downstream direction. The turbulence mechanism is also analyzed in some aspects, such as the coherent structure, the correlation function and the Probability Density Function （PDF） of the fluctuating velocity. The results show that the interaction between the two jets is strong near the jet exit and they are fully merged after a certain distance.

关键词： wall jet offset jet dilute characteristic coherent structure

Modelling of the behavior of marine oil spills: applications based on random walk techniques

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2000年第1期12卷 3-8页

作者： li, zhi-wei Mead, Christopher T. Zhang, Shu-Shen Dept. of Environ. Sci. and Technol. Dalian University of Technology Dalian 116012 China HR Wallingford Howbery Park Wallingford Oxon OX10 8BA United Kingdom

A numerical model has been developed to simulate the transport and fate of oil spilled at sea. The model combines the transport and fate processes of spilled oil with the random walk technique. Oil movement under the influence of tidal currents, wind driven currents, and turbulent eddies is simulated by the PLUME RW dispersion model developed by HR Wallingford. The weathering processes in the model represent physical and chemical changes of soil slicks with time, and comprise mechanical spreading, dispersion, evaporation and emulsification. Shoreline stranding is determined approximately using a capacity method for different shoreline types. This paper presents details of the model, and describe the results of various sensitivity tests. The model is suitable for oil spill contingency planning.

关键词： oil spill modelling random walk technique CLC number: TQ021 4 Document code: A

A new formula of recovery factor for non-equilibrium transport of graded suspended sediment in the Middle Yangtze River

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2023年第1期20卷 87-100页

作者： li lin-lin XIA Jun-qiang ZHOU Mei-rong DENG Shan-shan li zhi-wei State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China School of Civil Engineering Architecture and EnvironmentHubei University of TechnologyWuhan430068China

Suspended sediment concentrations in the Middle Yangtze River(MYR)reduced greatly after the Three Gorges Project operation,causing the composition of bed material to coarsen ***,little is known about the non-equilibrium transport of graded suspended sediment owing to different bed material compositions(BMCs)along the MYR,and it is necessary to determine the magnitude of recovery *** the Markov stochastic process in conjunction with the hiding-exposure effect of non-uniform bed-material,a new formula is proposed for calculating the recovery factor including the effect of different BMCs,and it is incorporated into the non-equilibrium transport equation to simulate the recovery processes of suspended load in both sand-gravel bed and sand bed reaches of the *** results show that:(i)the recovery rate of graded sediment concentrations at zhicheng was slower than that at Shashi during the period 2003-2007;(ii)the mean recovery factors of the coarse,medium,and fine sediment fractions in the zhichengShashi reach were 0.152,0.0012,and 0.0005,respectively,and the coarse sediment recovered up to the maximum sediment concentration of 0.138 kg/m3over a distance of 15 km;and(iii)the results of the new formula that can consider the effect of bed material composition are in general agreement with the field observations,and the spatial and temporal delay effects are inversely related to particle size and ***,the BMC effect on the nonequilibrium sediment transport in different reaches of the MYR needs to be considered for higher simulation accuracy.

关键词： non-equilibrium sediment transport bed material composition transition probability recovery factor Middle Yangtze River

Evaluation of five antibiotics on larval gut bacterial diversity of Plutella xylostella （Lepidoptera： Plutellidae）

在线全文

学校读者我要写书评

暂无评论

Insect Science 2015年第5期22卷 619-628页

作者： Xiao-li lin zhi-wei Kang Qin-Jian Pan Tong-Xian liu State Key Laboratory of Crop Stress Biology in Arid Areas and Key Laboratory of Northwest Loess Plateau Crop Pest Managementof Ministry of Agriculture Northwest A&F University Yangling Shaanxi 712100 China

Larvae of the diamondback moth, Plutella xylostella L. （Lepidoptera： Plutelli- dae）, have rich microbial communities inhabiting the gut, and these bacteria contribute to the fitness of the pest. In this study we evaluated the effects of five antibiotics （rifampicin, ampicillin, tetracycline, streptomycin sulfate and chloramphenicol） on the gut bacterial di- versity ofP xylostella larvae. We screened five different concentrations for each antibiotic in a leaf disc assay, and found that rifampicin and streptomycin sulfate at 3 mg/mL signif- icantly reduced the diversity of the bacterial community, and some bacterial species could be rapidly eliminated. The number of gut bacteria in the rifampicin group and strepto- mycin sulfate group decreased more rapidly than the others. With the increase of antibiotic concentration, the removal efficiency was improved, whereas toxic effects became more apparent. All antibiotics reduced larval growth and development, and eventually caused high mortality, malformation of the prepupae, and hindered pupation and adult emergence. Among the five antibiotics, tetracycline was the most toxic and streptomycin sulfate was a relatively mild one. Some dominant bacteria were not affected by feeding antibiotics alone. Denaturing gradient gel electrophoresis graph showed that the most abundant and diverse bacteria in P xylostella larval gut appeared in the cabbage feeding group, and diet change and antibiotics intake influenced gut flora abundance. Species diversity was significantly reduced in the artificial diet and antibiotics treatment groups. After feeding on the artificial diet with rifampicin, streptomycin sulfate and their mixture for 10 days, larval gut bacteria could not be completely removed as detected with the agarose gel electrophoresis method.

关键词： antibiotics endosymbiont gut bacteria microbes PCR-DGGE

Improved Goldstein filter for InSAR noise reduction based on local SNR

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Central South University 2013年第7期20卷 1896-1903页

作者： SUN Qian li zhi-wei ZHU Jian-jun DING Xiao-li HU Jun XU Bing School of Geosciences and Info-Physics Central South University Changsha 410083 China Department of Land Surveying and Geo-Informatics The Hong Kong Polytechnic University Hong Kong China

Although the modified Goldstein filter based on the local signal-to-noise （SNR） has been proved to be superior to the classical Goldstein and Baran filters with more comprehensive filter parameter, its adaptation is not always sufficient in the reduction of phase noise. In this work, the local SNR-based Goldstein filter is further developed with the improvements in the definition of the local SNR and the adaption of the filtering patch size. What＇s more, for preventing the loss of the phase signal caused by the excessive filtering, an iteration filtering operation is also introduced in this new algorithm. To evaluate the performance of the proposed algorithm, both a simulated digital elevation model （DEM） interferogram and real SAR deformation interferogram spanning the L＇ Aquila earthquake are carried out. The quantitative results from the simulated and real data reveal that up to 79.5% noises can be reduced by the new filter, indicating 9%-32% improvements over the previous local SNR-based Goldstein filter. This demonstrates that the new filter is not only equipped with sufficient adaption, but also can suppress the phase noise without the sacrifice of the phase signal.

关键词： interferometric synthetic aperture radar (InSAR) Goldstein filter signal-to-noise (SNR) adaptivity

Interventional treatment of acute hepatic artery occlusion after liver transplantation

在线全文

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2007年第5期6卷 474-478页

作者： li, zhi-wei Wang, Mao-Qiang Zhou, Ning-Xin liu, Zhe Huang, zhi-Qiang Dongguan Kanghua Hosp Dept Gen Surg Dongguan 523080 Peoples R China PLA Gen Hosp Dept Hepatobiliary Surg Beijing 100853 Peoples R China

BACKGROUND: With the development of the associated technology, interventional treatment has become an important method for the treatment of hepatic artery occlusion in some countries. This study was undertaken to evaluate the role of interventional methods in the diagnosis and treatment of acute hepatic artery occlusion after liver transplantation. METHODS: The diagnosis and treatment of 9 cases of acute hepatic artery occlusion after liver transplantation were retrospectively analyzed. RESULTS: In 109 cases of liver transplantation, 9 were diagnosed by angiography. Among them, 7 were diagnosed by Doppler ultrasound. After transcatheter thrombolysis, the hepatic arteries were partially or totally patent again in 6 cases of hepatic artery occlusion after liver transplantation, and stent placements in the hepatic artery were performed in 5 cases. All stents proved patent and no patient required another liver transplantation. CONCLUSIONS: Angiography plays an important role in diagnosing hepatic artery complications after liver transplantation. Interventional therapy is a valuable method in the treatment of acute hepatic artery occlusion after liver transplantation.

关键词： liver transplantation interventional treatment hepatic artery occlusion