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Search Results: 1 - 10 of 49483 matches for " Wen He "
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Study on Distribution Coefficient of Traction Return Current in High-Speed Railway  [PDF]
Wen Huang, Zhengyou He, Zhengyou He, Haitao Hu, Qi Wang
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B238
Abstract:

The distribution coefficient of return current network is an important method to decrease the rail potential. In order to resolve the problem of high rail potential in high-speed railway based on EN50122-1 and Pr EN50170 the distribution coefficient of longitudinal traction return current conductors is calculated through changing the interval of transverse connection. Based on field data and theoretical analysis, the parameters of longitudinal traction return current conductors are calculated. Results indicate that the best distance of the transverse connection is 400 m600 m.

Building Requirements Semantics for Networked Software Interoperability  [PDF]
Bin Wen, Keqing He, Jian Wang
Journal of Software Engineering and Applications (JSEA) , 2010, DOI: 10.4236/jsea.2010.32016
Abstract: Naturally, like the web, integrated software systems in Internet will have to be distributed and heterogeneous. To im-prove the interoperability of services for SAAS, it is crucial to build requirements semantics that will cross the entire lifecycle of services especially on requirements stage. In this paper, a requirements semantics interoperability extend-ing approach called Connecting Ontologies (CO) that will act as semantics information carrier designing to facilitate the requirements identification and services composition is proposed. Semantic measurement of Chinese scenario is explored. By adopting the approach, a series of tools support for transport domain are developed and applied based on CO and DPO (Domain Problem Ontology) to enforce requirements engineering of networked software efficiently.
A Love Wave Reflective Delay Line with Polymer Guiding Layer for Wireless Sensor Application
Wen Wang,Shitang He
Sensors , 2008, DOI: 10.3390/s8127917
Abstract: This paper presents an optimal design for a Love wave reflective delay line on 41o YX LiNbO3 with a polymer guiding layer for wireless sensor applications. A theoretical model was established to describe the Love wave propagation along the larger piezoelectric substrate with polymer waveguide, and the lossy mechanism from the viscoelastic waveguide was discussed, which results in the optimal guiding layer thickness. Coupling of modes (COM) was used to determine the optimal design parameters of the reflective delay line structured by single phase unidirectional transducers (SPUDTs) and shorted grating reflectors. Using the network analyzer, the fabricated Love wave reflective delay line was characterized, high signal noise ratio (S/N), sharp reflection peaks, and few spurious noise between the peaks were found, and the measured result agrees well with the simulated one. Also, the optimal guiding layer thickness of 1.5~1.8μm was extracted experimentally, and it is consistent with the theoretical analysis.
Effect of Ice-Temperature and Spermidine on Chilling Sensitivity of Pepper  [PDF]
Dongjie Liu, Guoliang Sui, Yongzhou He, Wen Qin, Ji Liu
Food and Nutrition Sciences (FNS) , 2013, DOI: 10.4236/fns.2013.42022
Abstract:

The peppers which were treated at ice-temperature for 6 hours and 1 mmol/L spermidine for 10 min, followed by cold storage (4 ± 1) respectively were investigated. The results indicated that the chilling injury was delayed and reduced by ice-temperature and spermidine treatments. Comparing with control group, ice-temperature and spermidine exerted significant effects on reduction of ascorbic acid (Vc) and chlororphyll contents, relatively high activity of superoxide dismutase (SOD), accumulation of malondialdehyde (MDA) as well as the increase of cell membrane penetrability. The results indicated that the spermidine and ice-temperature induced the activity of antioxidant enzyme SOD and maintained higher defence-related compound Vc as well as lower levels of membrane lipid peroxidation, which may be associated with chilling injury alleviation. There was a difference between ice-temperature treatment and spermidine treatment after 30 days. The results suggested that spermidine was more effective in reducing chilling sensitivity and prolonging storage of peppers.

Analysis on Effect of Parameters of Different Wind Generator on Power Grid Transient Stability  [PDF]
Zhi-wei Wen, Li Ding, Shi-en He
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B070
Abstract: To analyze the factors which affecting transient stability of power system, the dynamic model of doubly-fed induction generator and direct-drive PM synchronous generator has been built using PSCAD. Impact of different wind farm integration on grid typically in China has been presented. The influence of the variations of transient reactance, negative sequence reactance and rotary inertia on critical clearing time of power system transient stability is analyzed by time-domain simulation. Mixture operation of DFIG and PMSG to optimize the stability of system has been analyzed firstly. The digital simulation results show that doubly-fed induction wind turbines is a better choice to meet the requirement of system instability due to large wind farm integration in comparison with direct-drive PM synchronous wind turbines. With a rather large rotary inertia, the proper ratio of direct-drive PM synchronous wind turbines used in wind farm could be comprehensive planning by optimized the stability of system. Analysis of this paper should be provided as academic reference for improving design of wind farm system.

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Mathematical Statistics Method of Evaluating Application Effects of a New Type of Gas Anchor  [PDF]
Jun Wang, Wen-He Li, Rong Zhong
Energy and Power Engineering (EPE) , 2015, DOI: 10.4236/epe.2015.77029
Abstract: Based on the basic formula of the confidence interval and the sampling error of mathematical statistics, the mathematical statistics method of evaluating application effects of a new type of gas anchor was given in this paper. By the method mentioned above, the confidence interval and the sampling errors of the relevant mean value differences of Daqing Oilfield S block’s 150 wells, according to the mean value differences of the liquid producing capacity per day, the oil production per day, the submergence depth of the 10 sampling test wells, in which before and after a new type of gas anchor were laid down, were calculated. The calculation results show that a new type of gas anchor has a better effect of increasing oil production of oil well and enhancing pump efficiency. Through the real value differences analysis of the liquid producing capacity per day, the oil production per day, the submergence depth of 150 wells mentioned above, in which before and after a new type of gas anchor were laid down, it was verified. By using the confidence interval and the sampling errors of the liquid producing capacity per day, the oil production per day, the submergence depth mentioned above, in which before and after a new type of gas anchor were laid down, the application effects of a new type of gas anchor could be evaluated. And a mathematical statistics method of evaluation application effects of a new type of gas anchor is presented.
Sedimentary Environment of the Early Ordovician in Danzhai, Guizhou  [PDF]
Yu Pei, Youbin He, Jinxiong Luo, Yantao Zeng, Zhan Wen
Open Journal of Yangtze Oil and Gas (OJOGas) , 2017, DOI: 10.4236/ojogas.2017.23009
Abstract: This study analyzes the variations in trace element contents and ratios, the distribution patterns of rare earth elements, and the sedimentary environment and its evolution in the Early Ordovician. In particular, the analysis is based on measured section of the Qingjiang Village located in Nangao Town, Danzhai County, Guizhou Province. The analysis also considers thin sections and the characteristics of C, O isotopes. The lower part of the Tongzi Formation has a simple lithology and mainly consists of light gray to gray thin-medium bedded muddy dolomite and dolomicrite with a few dolarenites and dolorudites. The upper part of this formation includes gray thin-medium bedded fine crystalline dolomite and gray massive bioclastic limestone. Only a fraction of gray massive fine crystalline limestone, sparry calcarenite, and calcirudite are on top of the upper part. The Honghuayuan Formation is generally composed of light gray to gray medium-thick bedded or massive bioclastic limestone, reef limestone, and calcarenite with a few sandstones at the bottom. The δ18OPDB values of 18 samples are less than -11‰; in addition, the Pr/Pr* and Ce/Ce* ratios are greater and less than 1, respectively. These data reflect a sedimentary environment. The lower part of the Tongzi Formation might have been formed in an evaporite platform, which was then transformed into a restricted one, which featured a dry climate, a shallow water depth, and an insufficient amount of oxygen. By contrast, the upper part of the formation was deposited in an open platform, which featured a humid climate and relatively increased water depth and reducibility. During the sedimentary period of the Honghuayuan Formation, the water energy further increased, the climate became humid, the water depth increased, and the reducibility increased. Correspondingly, the sedimentary environment, which originally comprised littoral facies that slowly developed into an open platform and into a platform marginal bank, gradually evolved into a platform marginal reef.
Coupled Spin and Pseudo-magnetic Field in Graphene Nanoribbons
Wen-Yu He,Lin He
Physics , 2013, DOI: 10.1103/PhysRevB.88.085411
Abstract: Pseudo-magnetic field becomes an experimental reality after the observation of zero-field Landau level-like quantization in strained graphene, but it is not expected that the time-reversal symmetric pseudo-magnetic fields will have any effect on the spin degree of freedom of the charge carriers. Here, we demonstrate that spin-orbit coupling (SOC) could act as a bridge between pseudo-magnetic field and spin. In quantum spin Hall (QSH) states, the direction of the spin of edge states is tied to their direction of motion because of the SOC. The pseudo-magnetic field affects the clockwise and counter-clock-wise edge currents of the QSH states, and consequently lifts the degenerate edge states of opposite spin orientation. Because of opposite signs of the pseudo-magnetic field in two valleys of graphene, the one-dimensional charge carriers at the two opposite edges have different group velocities, and in some special cases the edge states can only propagate at one edge of the nanoribbon and the group velocity at the other edge becomes zero.
Distribution of c-erbB2 Antisense Probe Labeled with Superparamagnetic Iron Oxide Nanoparticles in the Major Organs of Mice on MR Imaging  [PDF]
Zhipeng Wen, Haiyan Liu, Hairong He, Shude Tan, Ming Wen, Shaolin Li
Advances in Nanoparticles (ANP) , 2013, DOI: 10.4236/anp.2013.21004
Abstract:

Background: The aim of this study was to investigate the distribution of the c-erbB2 antisense probe labeled with superparamagnetic iron oxide nanoparticles in the major organs of mice by MR imaging. Methods: Sixty BALB/c mice were randomly divided into experimental and control groups. MR scans were performed in each mouse of the experimental group at five different time points (10, 30, 60, 180 and 360 min) after injection of the antisense probe. The signal from each major organ (liver, spleen, heart, kidney and muscle tissue) in comparison with the background signal (signal to noise ratio) was determined at each time point as a measure of the distribution of the antisense probe. Six control mice were killed at each of the same time points and the organs immediately removed for determination of their iron content. Results: After injection of the antisense probe, the highest enrichment of the probe was seen in the spleen, reaching a peak at 180 min, followed by the liver, muscle, heart and kidney. Conclusions: MR imaging can visualize the distribution of c-erbB2 antisense probe labeled with superparamagnetic iron oxide nanoparticles in the major organs of mice, and this may provide the basis for further in vivo studies of MR imaging time and dose selection.

The status and progress of intraoperative ultrasonography
术中超声临床应用现状及进展

HE Wen,
何文

中华医学超声杂志(电子版) , 2010,
Abstract: 术中超声(intraoperative ultrasonography,IOUS)是在超声显像基础上为进一步满足临床外科诊断和治疗的需要发展起来的一门新技术,已发展成为超声医学的一个重要分支.
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