摘要：This paper presents a systematic approach of optimal design and control of a surface-mount, permanent-magnet synchronous torque motor for the next-generation machine tools. A step-by-step procedure of optimization integrates multiple performance objectives and constraints to help the designer make the best decision on the final motor geometry from both design and control perspectives. In the perspective of design, a torque motor with concentrated windings and similar numbers of slots and poles may achieve the desired performance after optimization for multiple objectives, leading to a sinusoidal flux density for a nearly ripple-free torque distribution. From the control perspective, an optimal current waveform with an ideal shift angle is determined for each phase by aligning the current excitation with the back electromotive force. Both design and control of the surface-mount, permanent magnet machine are verified by the finite element method, and a prototype is fabricated for performance validation.

摘要：目的为了解新疆北疆地区猪群中torque teno virus（TTV）感染流行情况。方法以TTV非编码区保守序列设计引物，采用PCR方法对猪源TTV进行检测，挑选部分阳性样品进行序列分析。结果共检测了该地区109份猪血样，检测结果表明，TTV1的感染率为56．88％（62／109）；TTV2的感染率为22．01％（24／109）；TTV1和TTV2混合感染率为18．34％（20／109）。同时，获得TTV1序列3个，TTV2序列4个，与参考序列相互比对，新疆北疆地区猪TTV1同源性为89．4％～95．2％；TTV2同源性为81．1％～99．2％。结论TTV在新疆北疆猪群中广泛存在，说明猪TTV是一个不容忽视的病原。

摘要：高性能计算已成为继理论研究和实验科学之后的第三种科研方法。如何高效地利用高性能计算平台上众多的设备为科研提供有效服务是管理者需要面对的主要问题。主要介绍基于开源软件torque的高性能计算平台记账系统的设计与实现,包括计算算法、系统架构、主要功能模块、数据设计及代码实现。通过归纳法分析torque日志记录模式,给出从作业角度和资源角度进行资源使用率的计算方法。该记账系统架构划分为五层,系统具有很好的灵活性和开放性,可以很容易地移植到其他平台或者其他类型的作业调度系统上。该系统更着重于当前资源的使用情况、用户资源使用情况、任务等待时间,而非简单的费用计算和账单打印,所以它更能为管理者和决策者提供有效且强大的数据支撑。

摘要：为了简化虚拟海战场构建方法,提高构建效率,提出了一种基于torque 3D引擎的虚拟海战场构建方法。与传统的方法相比,该方法采用torque 3D引擎自带的功能模块,通过导入3D模型形成战斗实体,结合粒子系统的思想,实现对真实数据地形的构建以及雨、闪电等自然天气和爆炸、烟雾等不规则形状物体的模拟。实验表明,利用该方法可以简单、快速的构建出虚拟海战场场景。

摘要：AC motors, especially the squirrel cage induction motors have the advantages of simple structure, good reliability and low cost. They are more suitable to be used as electrical dynamometers to provide dynamic load for bench test systems. But, the speed and torque of induction motors are not easy to be controlled accurately. In this work, an electrical dynamometer based on the induction motor is proposed. In order to get better control performance of torque and speed of induction motor, an improved direct torque control method(DTC) is also developed based on the space vector modulation(SVM) technique. The performance of the proposed dynamometer system is validated in the Matlab/Simulink platform. The simulation results show that the new dynamometer has good torque and stator flux response. And the torque and stator current ripples of it are reduced significantly compared with using the conventional DTC method.

摘要：Biomimetic blades for soil-rototilling and stubble-breaking were designed learning from the geometrical structure of the tips of toes of mole rat （Scaptochirus moschatus）. The orientation, the number and the central angle of the biomimetic structure were taken as the testing factors. The optimal structure of the biomimetic blade was determined through the tests of soil-rototilling and stubble-breaking operation in an indoor soil bin. The optimal combination of the biomimetic structure pa- rameters is that three arc concave teeth are equally arranged on the front cutting edge with a central angle of 60°. The results of comparative tests between the optimal biomimetic blade and a conventional universal blade show the torque acting on the biomimetic blade is lower during soil-rototilling and stubble-breaking operations. The results of field tests show that the working quality of the biomimetic blades meets the requirements of the national standard of China. Tests of soil-rototilling show that, when the orientation of the biomimetic structure was at low and middle levels, the torque ofbiomimetic blades decreased from 34.17 N·m to 31.03 N·m. The torque also decreased with the increase of the number of biomimetic structure. The average torques were 34.57 N·m, 33.44 N·m and 31.37 N·m, respectively. The maximum different value between two levels of central angle was 0.41 N·m. Tests in field indicate that for soil-rototilling operation, the tillage depth is deeper than 80 mm, the soil-crushing rate （length of soil block less than 40 mm） is over 50 %, and the vegetation coverage rate is over 55 %. For stubble-breaking operation, the stubble-breaking depth is deeper than 70 ram, the stubble-breaking rate （length of stubble less than 40 mm） is over 60%, and the stubble coverage rate is over 80%, which can meet the stubble-breaking requirement of corn.

摘要：Large diameter fans with low solidity are widely used in automotive application for engine cooling. Their designs with small chord length help reducing the torque on the electrical motor and providing a good aerodynamic compromise between several operating conditions, some of these being at high flow rate. Their global performances are measured according to the ISO standard DP 5801, which allows comparison of results from different facilities. However, some variations in global performances are observed when considering results from two different test rigs. On a fan selected for the purpose of this study, up to 6 % of efficiency is lost on the worst case. As efficiency is more than ever a key factor to select a component, some experimental and numerical investigations were conducted to analyze the fan behavior on each facility. Two sets of measurement and simulation are performed and compared. Geometries considered for the domain of computation include the test rig plenum, the torquemeter, the ground and a large domain for the atmospheric conditions. The exact fan geometry with tip clearance and under-hub ribs is also considered. Numerical results show a good agreement with experiment in both cases when convergence is reached and for low flow rate when computations are switched to unsteady mode. Comparisons show that simulations are able to capture the different fan behaviors depending on the confguration and those efficiency losses previously observed are correctly predicted. These results are further analyzed to perform some post-processing. Blade loading remains identical for both cases but disparities appear in the wake and its interaction with the surrounding. Tiny details that are often neglected during experiment and/or simulation appear to be the cause of slight variations. Position of the torquemeter and shape of the plenum are among the parameters that various and that have cumulative effects. Efficiency being a ration of pressure and torque, variations ar

摘要：简述了分布式文件元数据管理系统的应用环境和设计目标。目标系统设定应用于高能物理数据分析,关联torque作业批处理系统;在这些条件的限制下,详细分析了各种限制因素,并以此为基础给出了目标系统的总体结构及模块化设计。详细阐述了目标系统的数据库设计、访问接口设计以及数据同步要点,给出了设计思路,并结合目标系统的记录新增操作、查询操作的测试性能,讨论了进一步的工作。

摘要：为了解西南地区猪群中torque teno virus(TTV)感染流行情况,以TTV 5′非编码区(5′UTR)保守序列设计引物,建立了猪TTV检测的巢式PCR(nPCR)方法,并对该地区22个规模化养猪场363份血清进行了检测。结果表明,在被检血清样品中TTV1和TTV2感染率为79.6%、87.1%,两者的混合感染率为68.3%。证实TTV在西南地区猪群中广泛存在,提示人们应当重视防止TTV感染的进一步流行。

摘要：针对四轮轮毂电机电动汽车转向时四轮差速问题,进行了电子差速控制研究。设计了电子差速控制策略,建立差速运动参考模型,根据四轮轮毂电机电动汽车四轮驱动力矩独立可控的优势,通过驱动力矩分配器对四轮驱动力矩进行合理分配,实现了实际轮速跟踪参考轮速,并在Matlab/Simulink里搭建了四轮轮毂电机电动汽车电子差速系统模型,通过CarSim与Matlab/Simulink联合仿真进行了验证。结果表明:电子差速差速控制策略能够有效实现转向时四轮差速控制,提高电动汽车的操纵稳定性。