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Search Results: 1 - 10 of 36935 matches for " Zhao Yuelong "
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Liu Yanhu,Li Juzhang,Zhao Yuelong,

地理研究 , 1995,
Abstract: Natural disaster is a dynamic phenomenon varying from region to region and changingover time. The impacts of disasters to a region is usually described by the extent of disasteraffecting the region in general,and also by the grading of disaster for particular purposes.This paper deals with the regional characters of natural disaster of China by using informa-tion from l989 to 1993.It aims at analyzing interactions between disaster and regional devel-opment,identifying indicators used as tools for decision making in disaster reduction,and dis-cussing regional differences of disaster impacts in China. The paper fiistly reviews information available to describe disasters,and then dibcussesthe importance of differefit items of information in relation to various types of disasters. Based on the sigfiificance and the implication,an indicator system of disaster impacts is estab-lished.This system covers 8 basiic indicators as:disaster losses in absolute sense; disasterlosses in relativp sense;fluctuation in absolute sense;fluctuation in relative sense;disasterlosses per capita;disaster losses per unit area;affected population per unit area;and affectedland per unit area. In addition,the grading systems for each indicator are also developed. Adopting the indicator systein of ditqaster impacts,the paper concluded that the easternpart of China is the seriously affected area by natural disasters, which is the well developedarea in terms of economy,and the niost populated area of China. Within the easterii part ofChina,some regions:uch as the lower reach of the Yellow River,the Haihe River Basin,andthe lower reach of the Yangzi River siiffer tremcndously from natural disasters in the last fewyears. With,regards to the sustaining capacity to Withstand disasters,the paper emphasized thataregion could not be seH- reliant when disaster impact indictor a6ove 4.0in terms of absolutedisaste losses,or up to 30%in terins of relative disaster losses.

Zhao Yuelong,Zhang Lingjuan,

地理科学进展 , 1998,
Abstract: In this paper, a set of index and method on assessment of fragile environment is separately established. This is a systematic, complete, objective and flexible method of assessment of Fragile Environment. And it can be easily used in practice. At last, its practicality and accuracy are tested by using it to assess fragile degrees of environment within 26 provinces of China.
Coherent manipulation of spin wave vector for polarization of photons in an atomic ensemble
Shujing Li,Zhongxiao Xu,Haiyan Zheng,Xingbo Zhao,Yuelong Wu,Hai Wang,Changde Xie,Kunchi Peng
Physics , 2011, DOI: 10.1103/PhysRevA.84.043430
Abstract: We experimentally demonstrate the manipulation of two-orthogonal components of a spin wave in an atomic ensemble. Based on Raman two-photon transition and Larmor spin precession induced by magnetic field pulses, the coherent rotations between the two components of the spin wave is controllably achieved. Successively, the two manipulated spin-wave components are mapped into two orthogonal polarized optical emissions, respectively. By measuring Ramsey fringes of the retrieved optical signals, the \pi/2-pulse fidelity of ~96% is obtained. The presented manipulation scheme can be used to build an arbitrary rotation for qubit operations in quantum information processing based on atomic ensembles.
Quantum Interference of Stored Coherent Spin-wave Excitations in a Two-channel Memory
Hai Wang,Shujing Li,Zhongxiao Xu,Xingbo Zhao,Lijun Zhang,Jiahua Li,Yuelong Wu,Changde Xie,Kunchi Peng,Min Xiao
Physics , 2010, DOI: 10.1103/PhysRevA.83.043815
Abstract: Quantum memories are essential elements in long-distance quantum networks and quantum computation. Significant advances have been achieved in demonstrating relative long-lived single-channel memory at single-photon level in cold atomic media. However, the qubit memory corresponding to store two-channel spin-wave excitations (SWEs) still faces challenges, including the limitations resulting from Larmor procession, fluctuating ambient magnetic field, and manipulation/measurement of the relative phase between the two channels. Here, we demonstrate a two-channel memory scheme in an ideal tripod atomic system, in which the total readout signal exhibits either constructive or destructive interference when the two-channel SWEs are retrieved by two reading beams with a controllable relative phase. Experimental result indicates quantum coherence between the stored SWEs. Based on such phase-sensitive storage/retrieval scheme, measurements of the relative phase between the two SWEs and Rabi oscillation, as well as elimination of the collapse and revival of the readout signal, are experimentally demonstrated.
License plate recognition technology based on PSO-BP neural network

WU Zhipan
,ZHAO Yuelong,LUO Zhongliang,DU Huaying

- , 2017,
Abstract: 针对传统BP神经网络在车牌识别的应用领域中,存在经常性陷入局部最优,而导致识别效果不理想事实。提出一种基于PSOBP神经网络的车牌号码识别技术方法,该方法首先构建一个8-25-1的BP神经网络,再通过提取车牌的8像素比特征值作为BP神经网络的输入向量,然后采用粒子群算法(PSO)对该BP神经网络的权值和阈值进行优化,使其适应值达到最小。通过300副不同光照环境和污损的车牌识别仿真实验,验证了所提出的算法相对于传统的模板匹配算法和BP算法,具有输出误差小、全局收敛速度快和识别率高的特征,具有一定的应用价值
Di-μ-chlorido-bis{bis[3,5-dimethylpyrazol-1-yl-κN2)methane]iron(II)} bis[tetrachloridoferrate(III)]
HongYing Xia,YueLong Liu
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536808035253
Abstract: In the title complex, [Fe2Cl2(C11H16N4)4][FeCl4]2, the asymmetric unit is composed of one and a half units of [Fe(bdmpm)2Cl]2(FeCl4)2(bdmpm = bis(bis(3,5-dimethylpyrazol-1-yl)methane). The three independent FeII atom have a distorted octahedral coordination geometry comprising two bridging chloride anions and four N atoms from two bis(3,5-dimethylpyrazol-1-yl)methane ligands. The FeIII atom has a tetrahedral coordination geometry comprising four chloride anions.
On the Inviscid Limit of the 3D Navier-Stokes Equations with Generalized Navier-slip Boundary Conditions
Yuelong Xiao,Zhouping Xin
Mathematics , 2013,
Abstract: In this paper, we investigate the vanishing viscosity limit problem for the 3-dimensional (3D) incompressible Navier-Stokes equations in a general bounded smooth domain of $R^3$ with the generalized Navier-slip boundary conditions (\ref{VSg}). Some uniform estimates on rates of convergence in $C([0,T],L^2(\Omega))$ and $C([0,T],H^1(\Omega))$ of the solutions to the corresponding solutions of the idea Euler equations with the standard slip boundary condition are obtained.
On 3D Lagrangian Navier-Stokes $α$ model with a Class of Vorticity-Slip Boundary conditions
Yuelong Xiao,Zhouping Xin
Mathematics , 2012, DOI: 10.1007/s00021-012-0110-5
Abstract: This paper concerns the 3-dimensional Lagrangian Navier-Stokes $\alpha$ model and the limiting Navier-Stokes system on smooth bounded domains with a class of vorticity-slip boundary conditions and the Navier-slip boundary conditions. It establishes the spectrum properties and regularity estimates of the associated Stokes operators, the local well-posedness of the strong solution and global existence of weak solutions for initial boundary value problems for such systems. Furthermore, the vanishing $\alpha$ limit to a weak solution of the corresponding initial-boundary value problem of the Navier-Stokes system is proved and a rate of convergence is shown for the strong solution.
On the boundary of Tethyan tectonic domain on northeastern margin of the Tibetan Plateau

,] 赵志丹[,] 张本仁 张宏飞 张利 陈岳龙

岩石学报 , 2006,
Abstract: 东特提斯构造域北界的确定不仅可以约束构造域的范围及演化,而且对于约束中国各陆块的原始构造归属也有着非常重要的意义.本文将从地球化学角度对这一科学问题进行探讨.祁连造山带早古生代蛇绿岩单元内枕状玄武岩的元素、Sr-Nd-Pb同位素组成系统研究表明:其地幔源区的Nd和Pb同位素组成均表现出印度洋MORB型同位素组成特征;枕状玄武岩(△^207Pb/^204Pb)t变化范围为9.1~24.3(平均值为14.7),(△^208/^204Pb)t变化范围为9.1~101.1(平均值55.3);与古特提斯和新特提斯蛇绿岩具有一致的同位素组成.因此,祁连造山带古洋幔应属于原特提斯构造域.纵观中国境内的特提斯构造域蛇绿岩的分布特征可知:该构造域表现出自北而南变年轻的时空演化规律,从而说明中央造山带的动力学过程也应纳入冈瓦纳大陆裂解和亚洲增生的总动力学系统之中.
Discussion on the tectonic affinity of ancient oceanic mantle in Western Qinling-Songpan continental tectonic node, China: From elemental and Sr-Nd-Pb isotopic evidences

,] 赵志丹[,] 张宏飞 张本仁 张利 陈岳龙

岩石学报 , 2006,
Abstract: 西秦岭-松潘构造结是中国大陆中重要的构造转换域,为探讨不同陆块及古洋幔的构造归属提供了非常有利的条件。该构造结早古生代蛇绿岩单元内变质玄武岩的地球化学特征表明:其源区不具有高场强元素(HFSE)相对于大离子亲石元素(LILE)亏损的特征;稀土元素(REE)及其它不活泼元素特征表明蛇绿岩形成于与岛弧无关的环境。变质玄武岩的 Sr 同位素组成受到海水热液蚀变或后期变质作用的影响而有所改变。Nd-Pb 同位素组成特征表明其地幔源区具有典型的印度洋MORB 型同位素组成特征(传统意义上的"Dupal"异常),从而说明其地幔源区属于原特提斯构造域。西秦岭-松潘构造结古洋幔构造归属的研究不仅为研究该构造结内各微陆块构造归属提供重要的约束,也为研究有关陆块间造山带的性质、发展与演化提供了动力学背景。
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