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Search Results: 1 - 10 of 99066 matches for " YANG Tian-hong "
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Diversity of Ground-Dwelling Beetles (Coleoptera) in Larch Plantation with Different Stages of Reforestation in Wolong Natural Reserve, Southwestern China

YU Xiao-dong,LUO Tian-hong,YANG Jian,ZHOU Hong-zhang,

动物学研究 , 2006,
Abstract: 在四川卧龙国家自然保护区,以落叶松种植林邻近的天然落叶阔叶林(100年生,5块样地)为对照,分别选择刚种植(5年生)、幼年期(15年生)和成熟期(45年生)的3种落叶松林各4块样地,每个样地4个重复,研究森林不同恢复阶段地表甲虫的多样性。通过巴氏罐诱法取样,采集甲虫标本共7444号。步甲科、隐翅虫科和拟步甲科分别占总数的40·2%、38·3%和6·4%,共同构成本研究地区的优势类群。甲虫的科丰富度、多样性和均匀度在3种落叶松林内显著高于天然林,且在3种落叶松林中,刚种植的最高,幼年期的最低;个体数量正相反,天然林显著高于落叶松林,而且3种落叶松林内,幼年期最高,刚种植的最低。主坐标分析排序和聚类分析表明,不同树龄的落叶松林和天然阔叶林间的地表甲虫群落组成存在显著差异,成熟期落叶松林与幼年期落叶松林和天然阔叶林有较高的相似性。甲虫个体数量的季节变化在3种落叶松林内相似性很高,与天然阔叶林差异显著,而科丰富度、多样性和均匀度的季节变化在3种落叶松林以及天然阔叶林间相似性都很低。多元回归分析表明,林冠层、草本层及枯落物的高(厚)度和覆盖率是决定科丰富度、个体数量、多样性和均匀度的决定因素。以上结果表明,在科级水平上,地表甲虫群落组成在不同树龄的落叶松林以及天然落叶阔叶林内存在显著差异,虽然成熟期的落叶松林已经具有了部分天然阔叶林的甲虫群落特点,但仍无法完全恢复到天然林的群落水平。因此,在鼓励森林恢复的同时,保留大面积的天然落叶阔叶林免受破坏和干扰仍然是保护地表甲虫群落的必要措施。
The Application of Compressed Sensing to Stepped-frequency Ground Penetrating Radar Migration Imaging

Qu Le-le,Fang Guang-you,Yang Tian-hong,

电子与信息学报 , 2011,
Abstract: With the sparistiy of the target space, a novel migration imaging algorithm for the stepped-frequency GPR based on compressive sensing is proposed in this paper. The new imaging algorithm removes the direct wave in frequency domain in advance, estimates the regulation parameter with cross validation algorithm, and images the subsurface with sparistiy constraint. The simulation and experimental data show that the new imaging algorithm is effective and practical.

ZHANG Yong-bin,TANG Chun-an,ZHANG Huai,LIANG Zheng-zhao,MA Tian-hui,YANG Tian-hong,
,唐春安,张 怀,梁正召,马天辉,杨天鸿

岩石力学与工程学报 , 2006,
Abstract: Powerful and accurate computation is becoming one of the most important tools for rock failure process analysis and related rock engineering problems.It demands supercomputer or large-scale parallel computer and related software that can be run on them.Common personal computers(PC) and workstations are incapable when they are facing the accurate simulation of micro-scale crack formation and evolution in rocks and other different typs of materials,which requires terascale computing,even petascale super-computing in future.A parallel model of rock failure process analysis is proposed.This model is developed from serial version of rock failure process analysis(RFPA) directly,which has been presented before.Parallelism of finite element method(FEM) in stress module has been completed using discontinuous finite element method and domain decomposition parallel algorithms for parallelization of RFPA.Numerical test shows that the program is robust and possesses good scalability and pocketability.Stress analysis of tens of millions order linear equations has been finished within twenty five minutes on 32-node PC-cluster.
Purification of the antimicrobial compounds from Streptomyces xinghaiensis

ZHANG Shan-Shan,ZHAO Xin-Qing,CHEN Liang-Yu,YANG Tian-Hong,ZHANG Feng-Hua,

微生物学通报 , 2011,
Abstract: Streptomyces xinghaiensis is a novel Streptomyces species isolated from marine sediment sample collected in Xinghai Bay, Dalian, China, and wide spectrum of antimicrobial activities of its fermentation broth has been observed. In this study, the antibacterial activities of the fermentation broth of S. xinghaiensis against drug-resistant clinical isolates were investigated, and inhibitory activities against Acinetobacter baumannii and Staphylococcus aureus (MRSA) strains were revealed. Purification of the active compound (s) against methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates was performed and the properties of the active compounds were studied. Active fractions were obtained after treatments of the broth with macroporous adsorptive resin HP-20 and Sephadex LH-20. The active components were weak alkaloid compounds with no specific UV adsorption, and ninhydrin coloration further supported the hypothesis that the active compounds likely belong to aminoglycoside antibiotics. The draft genomic sequence of S. xinghaiensis was searched and a ribostamycin-related gene cluster was identified. However, Thin Layer Chromatography (TLC) analysis indicated that the major components of the active compounds are different from ribostamycin.

XU Tao,TANG Chun-an,SONG Li,YANG Tian-hong,LIANG Zheng-zhao,
徐 涛
,唐春安,宋 力,杨天鸿,梁正召

岩石力学与工程学报 , 2005,
Abstract: 根据煤岩体介质变形与瓦斯渗流的基本理论,考虑到煤岩介质材料力学性质的非均匀性特点以及煤岩介质变形破裂过程中透气性的非线性变化特性以及煤岩体变形破裂过程中瓦斯渗流与煤岩体变形间的耦合作用,在岩石破裂过程分析系统(RFPA2D)的基础上,建立了含瓦斯煤岩破裂过程流固耦合作用的RFPA2D–Flow耦合模型,并给出了RFPA2D–Flow耦合模型的数值求解方法。并应用该模型对石门掘进诱发煤与瓦斯的延期突出进行了数值模拟,模拟结果再现了含瓦斯煤岩在瓦斯压力、地应力及煤岩力学性质共同作用下渐进损伤破裂诱致突出的全过程,模拟结果进一步表明延期突出与瞬时突出都是地应力、瓦斯压力和煤体物理力学性质3个因素综合作用的结果,都具备突出的4个阶段,即应力集中阶段、应力诱发煤岩破裂阶段、瓦斯动力驱动裂纹扩展阶段和突出阶段,为进一步深入理解煤与瓦斯突出机理及瓦斯抽放防治突出等提供理论基础和科学依据。
Study of stone detection method based on edge extraction and track

WANG Rong-ben,YU Tian-hong,JIA Yang,GU Bai-yuan,GUO Lie,
,余天洪,贾 阳,顾柏园,郭 烈

计算机应用 , 2006,
Abstract: In order to realize a stone detection based on machine vision, SUSAN operator was used to segment an original image. The areas where stones may exist could be obtained by using edge track filter in the segmented image. The area in the original image could be dwindled by using a segmentation method based on invariable moments. A grads image could be obtained by using Sobel operator to enhance the edge of this area. The grads image was segmented and filtered by using edge track. The stone position in the original image could be acquired by coordinating projection for the grads image. Experiment results show that the proposed method is characterized by a definite adaptability to environment and real-timeness.
Radiative E1 decays of X(3872)
Tian-Hong Wang,Guo-Li Wang
Physics , 2010, DOI: 10.1016/j.physletb.2011.02.014
Abstract: Radiative E1 decay widths of $\rm X(3872)$ are calculated through the relativistic Salpeter method, with the assumption that $\rm X(3872)$ is the $\chi_{c1}$(2P) state, which is the radial excited state of $\chi_{c1}$(1P). We firstly calculated the E1 decay width of $\chi_{c1}$(1P), the result is in agreement with experimental data excellently, then we calculated the case of $\rm X(3872)$ with the assignment that it is $\chi_{c1}$(2P). Results are: ${\Gamma}({\rm X(3872)}\rightarrow \gamma \sl J/\psi)=33.0$ keV, ${\Gamma}({\rm X(3872)}\rightarrow \gamma \psi(2S))=146$ keV and ${\Gamma}({\rm X(3872)}\rightarrow \gamma \psi(3770))=7.09$ keV. The ratio ${{\rm Br(X(3872)}\rightarrow\gamma\psi(2{\rm S}))}/{{\rm Br(X(3872)}\rightarrow \gamma {\sl J}/\psi)}=4.4$ agrees with experimental data by BaBar, but larger than the new up-bound reported by Belle recently. With the same method, we also predict the decay widths: ${\Gamma}(\chi_{b1}(1\rm P))\rightarrow \gamma \Upsilon(1\rm S))=30.0$ keV, ${\Gamma}(\chi_{b1}(2\rm P))\rightarrow \gamma \Upsilon(1\rm S))=5.65$ keV and ${\Gamma}(\chi_{b1}(2\rm P))\rightarrow \gamma \Upsilon(2S))=15.8$ keV, and the full widths: ${\Gamma}(\chi_{b1}(1\rm P))\sim 85.7$ keV, ${\Gamma}(\chi_{b1}(2\rm P))\sim 66.5$ keV.
Well-posedness for two-dimensional steady supersonic Euler flows past a Lipschitz wedge
Gui-Qiang Chen,Tian-Hong Li
Mathematics , 2006,
Abstract: For a supersonic Euler flow past a straight wedge whose vertex angle is less than the extreme angle, there exists a shock-front emanating from the wedge vertex, and the shock-front is usually strong especially when the vertex angle of the wedge is large. In this paper, we establish the $L^1$ well-posedness for two-dimensional steady supersonic Euler flows past a Lipschitz wedge whose boundary slope function has small total variation, when the total variation of the incoming flow is sufficiently small. In this case, the Lipschitz wedge perturbs the flow and the waves reflect after interacting with the strong shock-front or the wedge boundary. We first obtain the existence of solutions in $BV$ when the incoming flow has small total variation by the wave front tracking method and then study the $L^1$ stability of the solutions. In particular, we incorporate the nonlinear waves generated from the wedge boundary to develop a Lyapunov functional between two solutions, which is equivalent to the $L^1$ norm, and prove that the functional decreases in the flow direction. Then the $L^1$ stability is established, so is the uniqueness of the solutions by the wave front tracking method. Finally, we show the uniqueness of solutions in a broader class, i.e. the class of viscosity solutions.
A Simple Lower Bound on the Noncoherent Capacity of Highly Underspread Fading Channels
Steven Herbert,Ian Wassell,Tian-Hong Loh
Mathematics , 2014,
Abstract: Communication channels are said to be underspread if their coherence time is greater than their delay spread. In such cases it can be shown that in the infinite bandwidth limit the information capacity tends to that of a channel with perfect receiver Channel State Information (CSI). This paper presents a lower bound on the capacity of a channel with finite bandwidth, expressed in a form which is mathematically elegant, and computationally simple. The bounding method exploits the fact that most actual channels are highly underspread; and that typically more is known about their impulse response than the channel time variation. The capacity is lower bounded by finding an achievable rate for individual time blocks which are shorter than the channel coherence time, in an orthogonal frequency division multiplexing system model. A highly underspread channel of particular interest is the invehicle channel, and a numerical example is given to verify that the capacity is indeed approximately that of a channel with perfect receiver CSI. The resulting lower bound is shown to be tighter than those previously derived.

LI Yuan-hui,NAN Shi-qing,ZHAO Xing-dong,YANG Tian-hong,TANG Chun-an,ZHANG Yong-bin,TAN Zhi-hong,

岩石力学与工程学报 , 2005,
Abstract: The stability of boundary pillar,which can be found across in mine shifting from open-pit to underground mining,is very important for safe production of underground mine. Based on the practice of Shirengou ore mine from open-pit to underground mining,the stabilities of boundary pillar at representative sections are calculated and analyzed by using the methods of limit equilibrium and numerical simulation. With the application of the limit equilibrium method and consideration of the thickness,span of boundary pillar,height of deposed rock,and obliquity of ore mine,the safety coefficients of all sections of boundary pillar are calculated, respectively. The safe thickness for boundary pillar has been modeled by the RFPA2D (rock failure process analysis)system,including deformation and failure of boundary pillar during caving. At the same time,the failure process of the different sections is simulated. By calculation,the safety and danger section of the boundary pillar is predicted. It validates the designed boundary pillar thickness and offers references to construction.
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