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Search Results: 1 - 10 of 73287 matches for " XU Tian-hua "
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Existence and Stability Periodic Solution for Prey-Predator System with Functional Response
XU Tian-hua
Journal of Chongqing Normal University , 2010,
Abstract: The existence and stability of periodic solution in Prey-Predator system with diffusion, time-delay and Holing type Ⅱ are invertigated by using the method of upper and lower solutions and comparison principle. It is shown that the globally asymptotically stale trivial solution (0,0) when *, the globally asymptotically stale semi-trival periodic solutions *, of the system by construction of a pair of upper and lower solution of parabolic periodic system *. It was obtained that the system have a pair of T-periodic quasi-solutions and the sector between the quasi-solutions is an attractor of the system with respect to very nonnegative initial function.(* Indicates a formula, please see the full text)
Stability and Periodic Solution to Competitive Lotka-Volterra System with diffusion and Infinite Distributed Delay
XU Tian-hua
Journal of Chongqing Normal University , 2009,
Abstract: A competitive Lotka-volterra systemwith diffusion and infinite distributed delays is investigated. It is shown that the globally asymptotically stable trivial solution, when r1(ai)>=0,(i=1,2),the globally asymptotically stable semi-trivial periodic solution(r1(t,x),),and 0,r2(t,x)) when p1(a1)<0,p1(a2)>=0,p1(a2)<0 of the models byconstruction of a pair of upper and lower solution (u1,u2),(0,0)of parabolic periodic system (aui(t,x)/at-Aiui(t,x)=ui(t,x)[ai(t,x)-bi(t,x)ui(t,x)],and in the use of eigenvalue theory and comparison principle. A T-periodic series are established by using the monotone iteration technique. It was obtained that the systems have a pair of periodic positive solutions with respect to every nonnegative initial function.
Spatial Heterogeneity and Classified Control of Agricultural Non-Point Source Pollution in Huaihe River Basin
淮河流域农业非点源污染空间特征解析及分类控制

ZHOU Liang,XU Jian-gang,SUN Dong-qi,NI Tian-hua,
周亮
,徐建刚,孙东琪,倪天华

环境科学 , 2013,
Abstract: Agricultural non-point source pollution is of importance in river deterioration. Thus identifying and concentrated controlling the key source-areas are the most effective approaches for non-point source pollution control. This study adopts inventory method to analysis four kinds of pollution sources and their emissions intensity of the chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) in 173 counties (cities, districts) in Huaihe River Basin. The four pollution sources include livestock breeding, rural life, farmland cultivation, aquacultures. The paper mainly addresses identification of non-point polluted sensitivity areas, key pollution sources and its spatial distribution characteristics through cluster, sensitivity evaluation and spatial analysis. A geographic information system (GIS) and SPSS were used to carry out this study. The results show that: the COD, TN and TP emissions of agricultural non-point sources were 206.74×104 t, 66.49×104 t, 8.74×104 t separately in Huaihe River Basin in 2009; the emission intensity were 7.69, 2.47, 0.32 t·hm-2; the proportions of COD, TN, TP emissions were 73%, 24%, 3%. The paper achieves that: the major pollution source of COD, TN and TP was livestock breeding and rural life; the sensitivity areas and priority pollution control areas among the river basin of non-point source pollution are some sub-basins of the upper branches in Huaihe River, such as Shahe River, Yinghe River, Beiru River, Jialu River and Qingyi River; livestock breeding is the key pollution source in the priority pollution control areas. Finally, the paper concludes that pollution type of rural life has the highest pollution contribution rate, while comprehensive pollution is one type which is hard to control.
A Sensitive and Rapid Assay for Investigating Vertical Transmission of Hepatitis B Virus via Male Germ Line Using EGFP Vector as Reporter
Mohamed Morsi M. Ahmed,Tian-Hua Huang,Qing-Dong Xie
Journal of Biomedicine and Biotechnology , 2008, DOI: 10.1155/2008/495436
Abstract: Hepatitis B virus (HBV) constitutes a serious menace to man. DNA recombination and sequencing, interspecific in vitro fertilization, single-embryo PCR and RT-PCR were employed to establish a sensitive and rapid assay for exploring the vertical transmission of viruses via male germ line. Plasmid pIRES2-EGFP-HBs which expressed enhanced green fluorescent protein as reporter for the expression of hepatitis B virus S gene was successfully constructed and confirmed by PCR, EcoR I and Sal I digestion, and DNA sequencing. After exposure to the plasmid, human spermatozoa were used to fertilize with zona-free hamster ova. Two-cell embryos were collected and classified into group A with green fluorescence and group B without green fluorescence under fluorescence microscope. The results showed that HBs DNA positive bands were detected in the embryos with green fluorescence (PCR and RT-PCR) and positive control (PCR) indicating expression of pIRES2-EGFP-HBs, and not observed in the embryos without green fluorescence and negative controls (PCR and RT-PCR) indicating no pIRES2-EGFP-HBs in the cells. The advantages and application foreground of this assay for study on vertical transmission of viruses such as HCV, HIV, HPV, and SARS via germ line were discussed.
MATING SYSTEM, PATERNITY ANALYSIS AND GENE FLOW IN PLANT POPULATIONS
植物种群交配系统、亲本分析以及基因流动研究

HE Tian-Hua,GE Song,
何田华
,葛颂

植物生态学报 , 2001,
Abstract: In the past two decades, the field of study of mating system and dispersal processes in plants has greatly expanded. Attention has particularly focused on the use of maternal progeny arrays to estimate short-term rates of outcrossing and selfing frequencies, and to examine patterns of pollen dispersal and male fertility variation within populations. Earlier studies relied on exclusion methods but realized that many gene flow events were not being detected by these techniques and that unique parentage could not be determined for a large proportion of the non-immigrant offspring in most natural populations. Consequently, methods for maximum-likelihood estimation of gene flow and male fertility have been introduced. Estimations of relative frequencies of outcrossing and selfing in populations and families based on single-locus and multi-locus models are discussed in this paper. Attention is given to the method of parentage analysis and the estimation of the level of gene flow. As an example, we present our studies of mating system and paternity analysis on Ophiopogon xylorrhizus, an endangered plant in China.
Infrared Image Denoising Based on Wavelet Transform
基于小波变换的红外图像去噪

YU Guo-qiao,LIU Tian-hua,
于国桥
,刘天华

红外 , 2007,
Abstract: Wavelet image denoising has become an important method for image denoising. In this paper, the basic principle of wavelet threshold denoising and the application of the wavelet threshold denoising algorithm to infrared noisy images are presented. Experimental results have shown that the algarithm is better than the traditional methods. It can effetively reduce the noise in images and can be used for the further analysis and processing of infrared images.
Bis(μ-2-phenylquinoline-4-carboxylato)bis[aqua(1,10-phenanthroline)(2-phenylquinoline-4-carboxylato)manganese(II)] dihydrate
Wei-Wei Li,Yue Bing,Mei-Qin Zha,Tian-Hua Li
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536811039341
Abstract: In the centrosymmetric dinuclear title complex, [Mn2(C16H10NO2)4(C12H8N2)2(H2O)2]·2H2O, the MnII cation is in a distorted octahedral coordination geometry defined by two N atoms from a 1,10-phenanthroline ligand, one water O atom and three O atoms from three 2-phenylquinoline-4-carboxylate anions. A pair of 2-phenylquinoline-4-carboxylate anions bridge two Mn cations, forming the dinuclear molecule. An intramoleculr O—H...O hydrogen bond occurs. Intermolecular O—H...O and O—H...N hydrogen bonds are present in the crystal structure.
4,4′-Dimethyl-2,2′-[1,2-phenylenebis(nitrilomethylidyne)]diphenol
Ke-Wei Lei,Hai-Mei Feng,Tian-Hua Zhou
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536807064768
Abstract: In the title Schiff base, C22H20N2O2, the benzene ring forms dihedral angles of 53.92 (1) and 3.62 (1)° with the two salicylaldimine groups. There are two strong O—H...N intramolecular hydrogen bonds. The crystal packing is stabilized by weak intermolecular C—H...O hydrogen bonds and π–π stacking interactions (average distance 3.39 ).
Differentiation of Bacillus thuringiensis and Escherichia coli by the Randomly Amplified Polymorphic DNA Analysis
Halima Hassan Salem,Tian-Hua Huang,Bahy Ahmed Ali,Qing-Dong Xie
Journal of Applied Sciences , 2006,
Abstract: Random Amplified Polymorphic DNA (RAPD) is a method of producing a biochemical fingerprint of a particular species. This study involved the isolation of DNA from three Bacillus thuringiensis (B. thuringiensis) [B. thuringiensis tenebrionis (tt4) and B. thuringiensis israelensis (i977)] as reference strains and new isolate B. thuringiensis strain (66) using the DNeasy Mini Kit (Qiagen, Inc. protocol). Two Escherichia coli (E. coli BL21 and E. coli C1a) DNAs are provided as components of RAPD Analysis Kit. RAPD analysis was performed using Ready-To-GoTM Analysis Beads and nine primers. Bands were then analyzed using a binary system and a phylogenetic tree created. The five strains segregated into two major clusters. The maximum linkage distance between the two major clusters was 103 units. First cluster consisted of two E. coli strains and the second cluster consisted of the three B. thuringiensis strains based on genetic similarity in their RAPD profiles. The B. thuringiensis reference strains were located in subcluster showing high similarity. Genetic similarities estimated as band sharing were calculated and all comparisons among bacterial strains have been done. The results showed that RAPD-PCR is powerful method for differentiation between B. thuringiensis and E. coli.
Genetic Similarity Among Four Bacillus thuringiensis subspecies Based on Random Amplified Polymorphic DNA (RAPD)
Halima Hassan Salem,Tian-Hua Huang,Bahy Ahmed Ali,Qing-Dong Xie
Journal of Biological Sciences , 2006,
Abstract: The aim of this study was to evaluate the genetic similarity and phylogenetic relationship among four Bacillus thuringiensis subspecies (new isolate and three reference strains). Random amplified polymorphic DNA (RAPD) technique was used in this study. Based on RAPD pattern obtained with total of seventeen random primers, the similarity index was calculated for each primer separately and the average for all primers was carried out with each comparison. Moreover, the scored band data was subjected to cluster analysis using Statistica/W5.0 Software package. Based on RAPD data obtained with all primers, the average of genetic similarities between the new isolate (66) and ACCC 10061, tt4 and i977 was 42.47; 51.10; and 45.90, respectively. The four strains are grouped into two major clusters A and B. Cluster A consisted of B. thuringiensis Berliner (ACCC 10061) strain and cluster B consisted of the three B. thuringiensis (66, tt4 and i977) strains. RAPD-PCR could be used extensively to study phylogenetic relationship among B. thuringiensis strains from different subspecies as well as for identification new isolate bacterial strains.
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