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高线速状态湿式离合器带排转矩特性研究
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作者 李杰 马超 王晓燕 《中国机械工程》 EI CAS CSCD 北大核心 2023年第22期2693-2703,2710,共12页
为研究湿式离合器空载状态下摩擦片高线速工况带排转矩产生回升变化的机理与规律,基于流体动力学模型,考虑润滑油膜表面张力与高线速油-气两相流的影响,建立了带排转矩数学模型和带排间隙油膜VOF两相流仿真模型,对油膜的变化进行分析验... 为研究湿式离合器空载状态下摩擦片高线速工况带排转矩产生回升变化的机理与规律,基于流体动力学模型,考虑润滑油膜表面张力与高线速油-气两相流的影响,建立了带排转矩数学模型和带排间隙油膜VOF两相流仿真模型,对油膜的变化进行分析验证。对模型进行分析获知,摩擦片高线速下油-气两相流产生部分带排转矩是带排转矩回升的主要原因。在摩擦元件高速带排试验系统中进行了带排转矩试验,分析了旋转方向、润滑油温度、流量、带排间隙、摩擦片尺寸对湿式离合器带排转矩的影响规律。 展开更多
关键词 湿式离合器 摩擦片 带排转矩 高线速
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高线速预涂卷材涂料
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作者 常霞俊 杨春娣 +1 位作者 胡宗留 徐徐 《涂料技术与文摘》 2008年第8期20-22,共3页
介绍了鸿业公司HY-E系列高线速预涂卷材涂料,包括底漆、面漆、背漆在固化时间22~25S范围内(板温224-241℃)的性能和特点。
关键词 预涂卷材涂料 高线速 底漆 背漆 面漆
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高速直齿轮齿面有限元网格精准离散方法 被引量:1
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作者 黄一伦 陈旭 胡玉梅 《重庆理工大学学报(自然科学)》 CAS 北大核心 2023年第3期129-137,共9页
为解决航空高速直齿圆柱齿轮齿面有限元网格精准离散的问题,提出一种可以适应轮齿啮合过程中齿面滚滑速度以及曲率半径变化的确定齿面网格尺寸的方法。根据齿轮啮合过程中的几何关系和主从动轮齿廓速度矢量关系,通过理论推导得出主从动... 为解决航空高速直齿圆柱齿轮齿面有限元网格精准离散的问题,提出一种可以适应轮齿啮合过程中齿面滚滑速度以及曲率半径变化的确定齿面网格尺寸的方法。根据齿轮啮合过程中的几何关系和主从动轮齿廓速度矢量关系,通过理论推导得出主从动轮齿廓上任意啮合点处的切向速度、相对滑移速度、曲率半径以及法向载荷的计算公式。以某航空发动机中的传动齿轮为例,利用公式计算得出航空发动机高速齿轮齿面曲率半径、切向速度、相对滑移速度以及载荷的大致范围。基于此范围,建立多组曲率半径适宜,转速和接触面网格尺寸不同且转速低及载荷恒定的圆柱滚子曲面接触有限元模型。利用两圆柱滚子曲面接触摩擦产生的滑移能损失模拟轮齿接触产生的滑移能损失,最终以滑移能损失仿真值与理论值之间的误差小于10%为前提,对比分析得出在不同齿面切向速度下,齿面网格尺寸与齿面曲率半径之间的最佳倍数关系。研究结果表明:选用合理的齿面网格尺寸能大大提高高速直齿圆柱齿轮有限元仿真结果的准确性。 展开更多
关键词 高线速 直齿圆柱齿轮 齿面网格离散 有限元仿真 滑移能
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离合器摩擦副摩滑过程轴向振动特性研究 被引量:8
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作者 王晓燕 李杰 +2 位作者 张志凯 王志勇 邢庆坤 《振动与冲击》 EI CSCD 北大核心 2017年第4期81-87,共7页
通过对摩擦副表面结构特征和接触力学等理论的应用,建立了热变形微观法向单元接触数学模型。采用数理统计和归一化方法,将微观模型转换成宏观数学模型,分析了摩擦副法向弹性接触特性,并引入Kelvin-Voigt(KV)模型,增加黏弹性接触微分算子... 通过对摩擦副表面结构特征和接触力学等理论的应用,建立了热变形微观法向单元接触数学模型。采用数理统计和归一化方法,将微观模型转换成宏观数学模型,分析了摩擦副法向弹性接触特性,并引入Kelvin-Voigt(KV)模型,增加黏弹性接触微分算子,构建了包含有应力和应变关系的黏弹性接触属性的数学模型,得到了摩擦副轴向振动数学模型。经仿真分析,获得了摩擦副摩滑过程的振动特性,同时对不同转速条件下的摩擦副摩滑过程轴向振动特性进行了实验测试。经对比分析,结果表明,仿真模型精度达到87%,仿真结果准确。这为进一步深入研究振动特性对摩擦副使用性能和寿命,具有理论研究和工程设计指导意义。 展开更多
关键词 摩擦片 振动特性 实验测试 高线速
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AN ANALYSIS METHOD FOR HIGH-SPEED CIRCUIT SYSTEMS 被引量:2
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作者 Dou Lei Wang Zhiquan 《Journal of Electronics(China)》 2006年第3期467-470,共4页
A new method for analyzing high-speed circuit systems is presented. The method adds transmission line end currents to the circuit variables of the classical modified nodal approach. Then the matrix equation describing... A new method for analyzing high-speed circuit systems is presented. The method adds transmission line end currents to the circuit variables of the classical modified nodal approach. Then the matrix equation describing high-speed circuit system can be formulated directly and analyzed conveniently for its normative form. A time-domain analysis method for transmission lines is also introduced. The two methods are combined together to efficiently analyze high-speed circuit systems having general transmission lines. Numerical experiment is presented and the results are compared with that calculated by Hspice. 展开更多
关键词 Transmission lines High-speed circuit system MacCormack method Circuit analysis
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Longitudinal type-line optimization of high-speed train for low aerodynamic noise 被引量:4
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作者 肖友刚 杨群 +1 位作者 孙亮 时彧 《Journal of Central South University》 SCIE EI CAS 2014年第6期2494-2500,共7页
The basic head shape of high-speed train is determined by its longitudinal type-line(LTL),so it is crucial to optimize its aerodynamic performance.Based on the parametric modeling of LTL constructed by non-uniform rel... The basic head shape of high-speed train is determined by its longitudinal type-line(LTL),so it is crucial to optimize its aerodynamic performance.Based on the parametric modeling of LTL constructed by non-uniform relational B-spline(NURBS)and the fluctuation pressure obtained by large eddy simulation(LES),the Kriging surrogate model(KSM)of LTL was constructed for low aerodynamic noise,and the accuracy of the KSM was improved gradually by adding the sample point with maximum expected improvement(EI)and the optimal point from optimization.The optimal objective was searched with genetic algorithm(GA).The results show that the total fluctuation pressure level(FPL)of the optimal LTL can be 8.7 dB less than that of original one,and the shape optimization method is feasible for low aerodynamic noise design. 展开更多
关键词 longitudinal type-line non-uniform relational B-spline (NURBS) aerodynamic noise fluctuation pressure level (FPL) shape optimization
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Influence of surface roughness on flotation kinetics of quartz 被引量:6
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作者 M.Rahimi M.R.Aslani B.Rezai 《Journal of Central South University》 SCIE EI CAS 2012年第5期1206-1211,共6页
Surface roughness of quartz particles was determined by measuring the specific surface area of particles.The wettability characteristics of particles were determined by measuring the flotation rate using a laboratory ... Surface roughness of quartz particles was determined by measuring the specific surface area of particles.The wettability characteristics of particles were determined by measuring the flotation rate using a laboratory flotation cell.Experimental results show that the rod mill product has higher roughness than the ball mill product.For the particles with larger surface roughness,the flotation kinetics constant is also higher.Finally,empirical relationships between surface roughness(r) and the flotation kinetics constant(k) of quartz particles as k=A+Br+Cr0.5lnr+D/lnr+E/r and k=A+Br are presented,in which A,B,C,D and E are constants related to experimental conditions and mineralogical properties of mineral. 展开更多
关键词 GRINDING flotation kinetics surface roughness ball mill rod mill
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Invited Paper: Antenna Selection in Energy Efficient MIMO Systems: A Survey 被引量:7
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作者 Zhou Xingyu Bai Bo Chen Wei 《China Communications》 SCIE CSCD 2015年第9期162-173,共12页
With the explosive growth and need for high-speed wireless communications, more and more energy is consumed to support the required quality of service. Therefore, energy efficient or green communication has become a v... With the explosive growth and need for high-speed wireless communications, more and more energy is consumed to support the required quality of service. Therefore, energy efficient or green communication has become a very hot topic under the ground of limited energy resource and environmentally friendly transmission schemes. MIMO technique is capable of reducing the transmission power thanks to its diversity and multiplexing gain. Moreover, antenna selection(AS) is an alternative to extract many of the benefits in MIMO systems with a reduced cost of complexity and power. Although many works including several survey papers have investigated AS in MIMO systems, the goal of these works is only the capacity maximization or error rate minimization, which fails to guarantee the optimality of the energy efficiency in MIMO systems. In this paper, we overview the state of the art in the AS schemes in energy efficient MIMO systems, the goal of which is to optimize the energy efficiency of the whole system. Specifically, we introduce energy efficient AS in point-to-point MIMO, cooperative MIMO, multiuser MIMO and largescale MIMO systems, respectively. Several challenging and practical issues in this area are also addressed. 展开更多
关键词 antenna selection energy efficient holistic power model MIMO
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Performance Evaluation of IEEE 1394b Serial Bus with Deterministic and Stochastic Petri Nets 被引量:4
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作者 王明 张春熹 伊小素 《China Communications》 SCIE CSCD 2013年第2期121-133,共13页
IEEE 1394b is a high-speed data bus that is widely used in local area networks and consumer electronics. To best utilize this data bus, we need to fully understand its per- formance. To evaluate its performance for bo... IEEE 1394b is a high-speed data bus that is widely used in local area networks and consumer electronics. To best utilize this data bus, we need to fully understand its per- formance. To evaluate its performance for both isochronous and asynchronous data transfers, we model the IEEE 1394b bus using Deterministic and Stochastic Pelri Nets (DSPNs), and conduct simulations using TimeNET 4.0. Using the DSPNs model, we simulate both the average waiting times of isochronous and asynchronous packets. From the simulation results, we determine the factors that influence performance, such as throughput, size of packets, arrival rate of packets, number of isochronous channels, and bus configuration. 展开更多
关键词 performance evaluation IEEE1394B isochronous data transfer asynchro-nous data transfer
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Route evaluation indexes of Changsha-Jishou freeway for protecting cultural heritages and natural environment 被引量:1
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作者 ZHANG Ying-xue LIU Zhao-hui 《Journal of Environmental Science and Engineering》 2009年第3期56-63,共8页
The highway construction inevitably may cause certain influence to the cultural heritage and the natural environment along the route, particularly in design stage; if the route selection is unreasonable, it will certa... The highway construction inevitably may cause certain influence to the cultural heritage and the natural environment along the route, particularly in design stage; if the route selection is unreasonable, it will certainly impact the natural resource seriously along the route. On the contrary, good design can reasonably develop, use, protect and promote the value of cultural heritage and natural environment. Changsha to Jishou (Chang-Ji) freeway is one section of Changsha to Chongqing freeway, which is one of the eight big west channels as planned in China; two cities of Changde and Huaihua and one autonomous region of Xianxi in western Hunan province, along which the cultural heritage and the natural resource are rich, and the natural landscape is exquisite. This paper investigates and analyzes the natural resources along the route of Chang-Ji freeway, puts forward some protection design evaluation indexes for mountain area freeway by the thought of context sensitive design. At last, the paper introduces the effect of applying the indexes to select route of Chang-Ji freeway. 展开更多
关键词 FREEWAY context sensitive design cultural heritage natural environment route selection
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DEVELOPMENT OF 50MW S-BAND KLYSTRON 被引量:1
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作者 Wang Yong Xie Jingxin Ding Yaogen Liu Pukun 《Journal of Electronics(China)》 2006年第3期471-472,共2页
This letter reports the development of a 50MW S-band klystron in the Institute of Electronics, Chinese Academy of Sciences (IECAS). It adopted a structure of six-cavity and single output window. Under conditions of ... This letter reports the development of a 50MW S-band klystron in the Institute of Electronics, Chinese Academy of Sciences (IECAS). It adopted a structure of six-cavity and single output window. Under conditions of an RF (Radio Frequency) pulse width of 4t, ts, a beam voltage of 305,9kV and a beam current of 368A, the peak output power has achieved 51.4MW with an efficiency of 45.6% and a gain of 54dB. 展开更多
关键词 50MW S-band klystron High peak power Design ideas
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Cluster-Based Content Download and Forwarding Scheme for Highway VANETs 被引量:3
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作者 mingsi zhang changle li +1 位作者 tao guo yuchuan fu 《China Communications》 SCIE CSCD 2018年第4期110-120,共11页
The recent advances in wireless communication technology enable high-speed vehicles to download data from roadside units(RSUs). However, the data download volume of individual vehicle is rather restricted due to high ... The recent advances in wireless communication technology enable high-speed vehicles to download data from roadside units(RSUs). However, the data download volume of individual vehicle is rather restricted due to high mobility and limited transmission range of vehicles, bringing users poor performance. To address this issue, we exploit the combination of both clustering and carry-and-forward schemes in this paper. Our scheme coordinates the cooperation of multiple infrastructures, cluster formation in the same direction and data forwarding of reverse vehicles to facilitate the target vehicle to download large-size content in dark areas. The process of data dissemination and achievable data download volume are then derived and analyzed theoretically. Finally, we conduct extensive simulations to verify the performance of the proposed scheme. Results show significant benefits of the proposed scheme in terms of increasing data download volume and throughput. 展开更多
关键词 clustering carry-and-forward^data dissemination data download volume
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Super-harmonic resonance of gear transmission system under stick-slip vibration in high-speed train 被引量:4
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作者 HUANG Guan-hua XU Si-si +1 位作者 ZHANG Wei-hua YANG Cai-jin 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第3期726-735,共10页
This work deals with super-harmonic responses and the stabilities of a gear transmission system of a high-speed train under the stick-slip oscillation of the wheel-set.The dynamic model of the system is developed with... This work deals with super-harmonic responses and the stabilities of a gear transmission system of a high-speed train under the stick-slip oscillation of the wheel-set.The dynamic model of the system is developed with consideration on the factors including the time-varying system stiffness,the transmission error,the tooth backlash and the self-excited excitation of the wheel-set.The frequency-response equation of the system at super-harmonic resonance is obtained by the multiple scales method,and the stabilities of the system are analyzed using the perturbation theory.Complex nonlinear behaviors of the system including multi-valued solutions,jump phenomenon,hardening stiffness are found.The effects of the equivalent damping and the loads of the system under the stick-slip oscillation are analyzed.It shows that the change of the load can obviously influence the resonance frequency of the system and have little effect on the steady-state response amplitude of the system.The damping of the system has a negative effect,opposite to the load.The synthetic damping of the system composed of meshing damping and equivalent damping may be less than zero when the wheel-set has a large slippage,and the system loses its stability owing to the Hopf bifurcation.Analytical results are validated by numerical simulations. 展开更多
关键词 stick-slip vibration super-harmonic resonance Hopf bifurcation gear transmission system high-speed train
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Dependence of Quantum Yields on Size of Ag Nano-particle Embedded in BaO Thin Film
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作者 CAIWu-de YANGYi-bing 《Semiconductor Photonics and Technology》 CAS 2002年第1期27-31,共5页
Theoretical dependence of the quantum yields on the size of Agnano-particle distribution from 0.8 nm to 37 nm embedded in BaOsemiconductor is discussed. The calculation results show that theincrease in Ag nano-particl... Theoretical dependence of the quantum yields on the size of Agnano-particle distribution from 0.8 nm to 37 nm embedded in BaOsemiconductor is discussed. The calculation results show that theincrease in Ag nano-particle diameter leads to the increase of thequantum yield threshold and the emergence of the rough Gaussian form,the results also shown that the greater increase in Ag nano-particlediameter causes the emergence of the exact Gaussian form and makesthe peaks rise up. 展开更多
关键词 quantum yield ag nano-prticles ultrafast nonlinear response
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High quality-performance by changing parameters of antenna array
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作者 XU Xue-mei WEN Jun +3 位作者 CHENG Wei SUN Ke-hui DING Yi-peng JIANG Zhao-hui 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第1期146-156,共11页
Several antennas based on cylindrical array and uniform hexagonal array are designed and fabricated on flexible substrate-Teflon.To validate the designed prototypes,the antennas are fabricated and their performance is... Several antennas based on cylindrical array and uniform hexagonal array are designed and fabricated on flexible substrate-Teflon.To validate the designed prototypes,the antennas are fabricated and their performance is analyzed.The highlight scheme is to improve the signal performance and electromagnetic field distribution by appropriately changing the parameters of the antennas array,signal frequencies,and steering angles.The proposed antennas array is capable of applying shaping radiation band technique to generate tunable power and radiation domain.The distribution of the field,and the bit-error-rate transmigration coefficient characteristics are measured.The results show that the proposed scheme can achieve better performance by searching the optimal parameters of antenna array. 展开更多
关键词 array antenna structure BIT-ERROR-RATE electromagnetic beam antenna parameters high speed frequencies
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Wireless Relay Communication on High Speed Railway:Full Duplex or Half Duplex? 被引量:3
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作者 Jia You Zhangdui Zhong +2 位作者 Zhongzhao Dou Jing Dang Gongpu Wang 《China Communications》 SCIE CSCD 2016年第11期14-26,共13页
In this paper,we introduce one full-duplex(FD) relaying transmission scheme for high speed railway and compare its ergodic capacity and outage performance with half-duplex(HD) relaying scheme. Both decode-and-forward(... In this paper,we introduce one full-duplex(FD) relaying transmission scheme for high speed railway and compare its ergodic capacity and outage performance with half-duplex(HD) relaying scheme. Both decode-and-forward(DF) amplify-and-forward(AF) relay modes are considered. Moreover,the carriage penetration loss(CPL) and the self-interference(SI) cancellation ratio are investigated. We derive the closed-form expressions for the outage probability and ergodic capacity of both HD and FD relay transmission schemes. It is shown that when CPL is larger than a certain level,the FD relay can achieve better performance in terms of capacity and keep the outage probability in a low level. It is also found that three factors: AF or DF modes,CPL and SI cancellation ratio,can have impact on capacity performance,and that CPL is one decisive factor. Our results can provide theoretical supports for development and deployment of future wireless communication systems on high speed railways. 展开更多
关键词 full duplex relay high speed railway mobile relay outage probability channel capacity
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Study on the Servo Drive of PM-LSM to Be Used in Parallel Synchronous Drive 被引量:1
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作者 Hiroyuki Takai Suzuki Kenji Hideo Dohmeki 《Journal of Mechanics Engineering and Automation》 2015年第10期580-584,共5页
Recently, linear motors can have high speed control, high acceleration-deceleration. So linear motors are widely used in industrial applications such as precision machine tools. In our laboratory focusing on transport... Recently, linear motors can have high speed control, high acceleration-deceleration. So linear motors are widely used in industrial applications such as precision machine tools. In our laboratory focusing on transport system, we propose parallel synchronous drive of used the PM-LSM (permanent magnet linear synchronous motor). It can pass luggage without having to stop the working. When you establish "parallel synchronous drive", a motor follows the other motor. In our laboratory, one of the motors is called "master motor" and the other motor called "slave motor". The master motor's speed and position pass slave motor then establish parallel synchronous drive. Therefore, slave motor requires high-responsive and precision that follows the master motor. This paper focuses on the control of the slave motor. 展开更多
关键词 PM-LSM master-slave motor PI control parallel synchronous drive method.
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A NOVEL PHYSICAL-LAYER TRANSCEIVER USED IN USB2.0 SERIAL DATA LINK 被引量:1
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作者 Li Haoliang He Lenian Wang Zi Yan Xiaolang 《Journal of Electronics(China)》 2006年第5期736-740,共5页
The paper proposes a novel transceiver in physical layer for high-speed serial data link based upon Universal Serial Bus (USB) 2.0, comprising transmitter and receiver. In the design, transmitter contains pre-and-main... The paper proposes a novel transceiver in physical layer for high-speed serial data link based upon Universal Serial Bus (USB) 2.0, comprising transmitter and receiver. In the design, transmitter contains pre-and-main driver to satisfy slew rate of output data, receiver includes optimized topology to improve preci- sion of received data. The circuit simulation is based on Cadence’s spectre software and Taiwan Semiconduc- tor Manufacture Corporation’s library of 0.25μm mixed-signal Complementary Metal-Oxide Semiconductor (CMOS) model. The front and post-simulation results reveal that the transceiver designed can transmit and re- ceive high-speed data in 480Mbps, which is in agreement with USB2.0 specification. The chip of physi- cal-layer transceiver has been designed and implemented with 0.25μm standard CMOS technology. 展开更多
关键词 Complementary Metal-Oxide Semiconductor(CMOS) transceiver Physical layer High-speed Universal Serial Bus (USB) 2.0
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Adaptive Antenna-Activation Based Beamforming for Large-Scale MIMO Communication Systems of High Speed Railway 被引量:3
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作者 Meng Cheng Shaoshi Yang Xuming Fang 《China Communications》 SCIE CSCD 2016年第9期12-23,共12页
Large-scale array aided beamforming improves the spectral efficiency(SE) as a benefit of high angular resolution.When dual-beam downlink beamforming is applied to the train moving towards cell edge,the inter-beam ambi... Large-scale array aided beamforming improves the spectral efficiency(SE) as a benefit of high angular resolution.When dual-beam downlink beamforming is applied to the train moving towards cell edge,the inter-beam ambiguity(IBA) increases as the directional difference between beams becomes smaller.An adaptive antenna activation based beamforming scheme was proposed to mitigate IBA.In the district near the base station(BS),all antenna elements(AEs) were activated to generate two beams.As the distance from the train to the BS increased,only the minimum number of AEs satisfying the resolution criterion would be activated.At the cell edge,one beam was switched off due to intolerable IBA.The proposed scheme can achieve SE gain to the non-adaptive scheme and show more robustness against the direction-of-arrival(DOA) estimation error. 展开更多
关键词 wireless communications adap- tive antenna activation large-scale antenna array downlink beamforming high speed railway
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A Study on the Structure of Linear Synchronous Motor for 600 km/h Very High Speed Train
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作者 Chan-Bae Park Byung-Song Lee 《Journal of Energy and Power Engineering》 2014年第2期374-378,共5页
Recently, an interest in a hybrid system combining only the merits of the conventional wheel-rail system and Maglev propulsion system is growing as an alternative to high-speed maglev train. This hybrid-type system is... Recently, an interest in a hybrid system combining only the merits of the conventional wheel-rail system and Maglev propulsion system is growing as an alternative to high-speed maglev train. This hybrid-type system is based on wheel-rail method, but it enables to overcome the speed limitation by adhesion because it is operated through a non-contact method using a linear motor as a propulsion system and reduce the overall construction costs by its compatibility with the conventional railway systems. Therefore, a comparative analysis on electromagnetic characteristics according to the structural combinations on the stator-mover of LSM (linear synchronous motor) for VHST (very high speed train) maintaining the conventional wheel-rail method is conducted, and the structure of coreless superconducting LSM suitable for 600 km/h VHST is finally proposed in this paper. 展开更多
关键词 Very high speed train linear synchronous motor CORELESS SUPERCONDUCTIVITY wheel-rail.
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