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Search Results: 1 - 10 of 81040 matches for " Xinping Liu "
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Simulation Analysis of Car Front Collision Based on LS-DYNA and Hyper Works  [PDF]
Chunke Liu, Xinping Song, Jiao Wang
Journal of Transportation Technologies (JTTs) , 2014, DOI: 10.4236/jtts.2014.44030
Abstract: Based on the basic principle of vehicle crash analysis using the finite element method, a car finite element model was built by using Hypermesh software. To simulate the front collision test of the car, the LS-DYNA software is adopted to calculate the deformation of the car and the acceleration time history curves during the crashing process; the anti-impact capability of the car is evaluated from this simulation. The results demonstrate that the improvement of local structure can promote the crashworthiness of the car, but the further improvement needs a major change of the car structure.
A novel configuration model for random graphs with given degree sequence
Xinping Xu,Feng Liu
Physics , 2007, DOI: 10.1088/1009-1963/16/2/002
Abstract: Recently, random graphs in which vertices are characterized by hidden variables controlling the establishment of edges between pairs of vertices have attracted much attention. Here, we present a specific realization of a class of random network models in which the connection probability between two vertices (i,j) is a specific function of degrees ki and kj. In the framework of the configuration model of random graphs, we find analytical expressions for the degree correlation and clustering as a function of the variance of the desired degree distribution. The expressions obtained are checked by means of numerical simulations. Possible applications of our model are discussed.
Continuous-time quantum walks on one-dimension regular networks
Xinping Xu,Feng Liu
Physics , 2008, DOI: 10.1103/PhysRevE.77.061127
Abstract: In this paper, we consider continuous-time quantum walks (CTQWs) on one-dimension ring lattice of N nodes in which every node is connected to its 2m nearest neighbors (m on either side). In the framework of the Bloch function ansatz, we calculate the spacetime transition probabilities between two nodes of the lattice. We find that the transport of CTQWs between two different nodes is faster than that of the classical continuous-time random walk (CTRWs). The transport speed, which is defined by the ratio of the shortest path length and propagating time, increases with the connectivity parameter m for both the CTQWs and CTRWs. For fixed parameter m, the transport of CTRWs gets slow with the increase of the shortest distance while the transport (speed) of CTQWs turns out to be a constant value. In the long time limit, depending on the network size N and connectivity parameter m, the limiting probability distributions of CTQWs show various paterns. When the network size N is an even number, the probability of being at the original node differs from that of being at the opposite node, which also depends on the precise value of parameter m.
Phase space patterns of quantum transport on ordered and disordered networks
Xinping Xu,Feng Liu
Physics , 2008, DOI: 10.1103/PhysRevA.77.062318
Abstract: In this paper, we consider the quantum-mechanical phase space patterns on ordered and disordered networks. For ordered networks in which each node is connected to its 2m nearest neighbors (m on either side), the phase space quasi-probability of Wigner function shows various patterns. In the long time limit, on even-numbered networks, we find an asymmetric quasi-probability between the node and its opposite node. This asymmetry depends on the network parameters and specific phase space positions. For disordered networks in which each edge is rewired with probability p>0, the phase space displays regional localization on the initial node.
Mechanism for linear preferential attachment in growing networks
Xinping Xu,Feng Liu,Lianshou Liu
Physics , 2007, DOI: 10.1016/j.physa.2005.04.005
Abstract: The network properties of a graph ensemble subject to the constraints imposed by the expected degree sequence are studied. It is found that the linear preferential attachment is a fundamental rule, as it keeps the maximal entropy in sparse growing networks. This provides theoretical evidence in support of the linear preferential attachment widely exists in real networks and adopted as a crucial assumption in growing network models. Besides, in the sparse limit, we develop a method to calculate the degree correlation and clustering coefficient in our ensemble model, which is suitable for all kinds of sparse networks including the BA model, proposed by Barabasi and Albert.
Oxygen-18 in different waters in Urumqi River Basin

ZHANG Xinping,YAO Tandong,LIU Jingmiao,

地理学报 , 2003,
Abstract: The variations of the stable oxygen isotope in different water mediums in Urumqi River Basin, China, are analyzed. The stable oxygen isotope in precipitation has marked temperature effect either under synoptic or seasonal scale at the head of Urumqi River. The linear regression equations of δ18O against temperature are δ18O=0.94T-12.38 and δ18O=1.29T-13.05 under the two time scales, respectively. The relatively large δ18O/temperature slopes show the strong sensitivity of δ18O in precipitation to temperature variation at the head of Urumqi River. According to the analyses on the δ18O in precipitation sampled at three stations with different altitudes along Urumqi River, altitude effect is notable in the drainage basin. The δ18O/altitude gradients have distinct differences: the gradient from Urumqi to Yuejinqiao is merely -0.054‰/hm, but -0.192‰/hm from Yuejinqiao to Daxigou, almost increasing by 2.6 times over the former. No altitude effect is found in surface firn in the east branch of Glacier No.1 at the head of Urumqi River, showing that precipitation in the glacier is from the cloud cluster with the same condensation level. Influenced by strong ablation and evaporation, the δ18O in surface firn increases with increasing altitude sometimes. Survey has found that the δ18O in meltwater at the terminus of Glacier No.1 and in stream water at Total Control have the similar change trend with the former all smaller than the latter, which displays the different runoff recharges, and all mirror the regime of temperature in the same term basically.
Fractionation mechanism of stable isotope in evaporating water body

ZHANG Xinping,TIAN Lide,LIU Jingmiao,

地理学报 , 2005,
Abstract: Under Rayleigh equilibrium condition, stable isotopic ratio in residual water increases with the decrease of the residual water proportion f exponentially, and the fractionation rate of stable isotopes is inversely proportional to temperature. However, under kinetic evaporation condition, the fractionation of stable isotopes is not only related to the phase temperature but also influenced by the atmospheric humidity and the mass exchange between liquid and vapor phases. The ratio δ in residual water will not change with f after undergoing evaporation of a long time for great relative humidity. The rate that the evaporating water body reaches isotopic steady state is mainly dependent on the relative humidity in atmosphere. The analysis shows that the actual mean linear variety rates, about -30.0, of the δ18O in residual water versus the residual water proportion at Nagqu and Amdo stations are consistent with the simulated process under temperature of 20 oC and relative humidity of 50%. The distillation line simulated under Rayleigh equilibrium condition is analogous to the global meteoric water line (MWL) as the temperature is about 20 oC. Under non-equilibrium condition, the slope and constant values of distillation line are directly proportional to temperature and relative humidity. According to the basic data, the simulated distillation line is very consistent with the actual distillation line of Qinghai Lake.
Twenty-Year Reform of Teaching Biochemistry and Molecular Biology at Fourth Military Medical University in China  [PDF]
Jing Zhao, Yan Li, Bo Yan, Lintao Jia, Xia Li, Lifeng Wang, Xinping Liu, Libo Yao
Open Journal of Social Sciences (JSS) , 2014, DOI: 10.4236/jss.2014.24029
Abstract: Higher medical education in China is dually challenged by inadequate understanding of career motivation among high school graduates and by insufficient self-directed learning capability as a result of long-term exam-based education. Biochemistry and Molecular Biology is one of the most essential basic courses at Fourth Military Medical University (FMMU), but students usually feel torn to deal with it. We have been making efforts to improve teaching efficiency for over twenty years. Our teaching reform involves design of students-centered experimental course, reorganization of theoretical course and attempt to evoke critical thinking in class. A few tips are shared with regards to how to make the course of Biochemistry and Molecular Biology more rewarding.
Growing small-world networks based on a modified BA model
Xinping Xu,Feng Liu,Wei Li
Physics , 2007, DOI: 10.1088/0256-307X/23/3/062
Abstract: We propose a simple growing model for the evolution of small-world networks. It is introduced as a modified BA model in which all the edges connected to the new nodes are made locally to the creator and its nearest neighbors. It is found that this model can produce small-world networks with power-law degree distributions. Properties of our model, including the degree distribution, clustering, and the average path length are compared with that of the BA model. Since most real networks are both scale-free and small-world networks, our model may provide a satisfactory description for empirical characteristics of real networks.
Empirical analysis of the ship-transport network of China
Xinping Xu,Junhui Hu,Feng Liu
Physics , 2007, DOI: 10.1063/1.2740564
Abstract: Structural properties of the ship-transport network of China (STNC) are studied in the light of recent investigations of complex networks. STNC is composed of a set of routes and ports located along the sea or river. Network properties including the degree distribution, degree correlations, clustering, shortest path length, centrality and betweenness are studied in different definition of network topology. It is found that geographical constraint plays an important role in the network topology of STNC. We also study the traffic flow of STNC based on the weighted network representation, and demonstrate the weight distribution can be described by power law or exponential function depending on the assumed definition of network topology. Other features related to STNC are also investigated.
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