基于PMM8731和SI-7300的步进电机驱动电路

PMM8731是日本三洋电机公司生产的步进电机脉冲分配器。而SI-7300则是日本三青公司生产的高性能步进电机集成功率放大器。它们和单片机一起可构成一种高效电机控制驱动电路。文中介绍了PMM8713与SI-7300的功能 ,给出了由它们组成的功率驱动电路及其在步进电机上的应用方法     

平面运动机构试验的数值模拟

获取水动力导数是预报船舶操纵性的关键,平面运动机构试验是主要的测量方法.该文通过商业软件FLUENT提供的动网格功能对DTMB5415模型的平面运动机构试验进行了数值模拟,忽略了自由面兴波,计算得到的侧向力及转首力矩的变化与实验结果吻合良好,为使用CFD预报船舶操纵性提供了相关经验.     

一种实用的三相步进电机驱动器的设计

利用PMM8713和LM331设计了一种实用的步进电机驱动器,着重介绍了驱动器系统电路及控制原理。     

An integration system for investment casting mould design of aeroengine turbine blade

An integration system was developed to satisfy the need of information integration in the process of designing, investment casting and monitoring aero-engine＇s turbo blade. The general architecture is detailed presented in this paper. The system mainly comprises of product master model, design information management, anti-deformation design of mould cavity, intelligence mould design and blade testing. The developed system can manage mould design and blade test data flow, optimize mould design process and achieve the goal of integration design.     

NUMERICAL PREDICTION OF SUBMARINE HYDRODYNAMIC COEFFICIENTS USING CFD SIMULATION

The submarine Hydrodynamic coefficients are predicted by numerical simulations.Steady and unsteady Reynolds Averaged Navier-Stokes(RANS) simulations are carried out to numerically simulate the oblique towing experiment and the Planar Motion Mechanism(PMM) experiment performed on the SUBOFF submarine model.The dynamic mesh method is adopted to simulate the maneuvering motions of pure heaving,pure swaying,pure pitching and pure yawing.The hydrodynamic forces and moments acting on the maneuvering submarine are obtained.Consequently,by analyzing these results,the hydrodynamic coefficients of the submarine maneuvering motions can be determined.The computational results are verified by comparison with experimental data,which show that this method can be used to estimate the hydrodynamic derivatives of a fully appended submarine.     

基于PMM OR03＋EPl83探头组合的环境电场检测仪设计

摘要i提出了一种基于意大利PMM公司的PMM01103＋EPl83探头组合的新型环境电场测试仪的设计方案。硬件由主机和探头2大模块组成,主机利用LPC2478作为MCU,实现按键操作,屏幕显示,数据存储,数据处理运算等功能,并完成探头的测量数据接收。     

基于重叠网格技术数值模拟船舶纯摇首运动

该文采用基于非定常RANS方程的黏性数值模拟方法,对标准船模DTMB5512裸船体在平面运动机构(PMM)控制作用下的纯摇首运动进行了数值模拟。文中数值计算采用基于开源CFD工具包Open FOAM和重叠网格技术开发的多功能水动力学求解器naoe-FOAM-SJTU。根据SIMMAN2014提供的标准算例,对同一运动频率下,在Fn=0.28工况下的3种不同运动幅值的纯摇首运动进行了数值计算,得出了船舶不同工况下的阻力、侧向力和转首力矩的历时曲线。并且根据操纵性数学模型(MMG)推导出相应的水动力导数值,所有计算结果同模型试验数据吻合较好,验证了采用当前处理方法数值求解纯摇首运动的可靠性。     

复配缓蚀剂(PMM)对银缓蚀效果的电化学研究

采用极化曲线测量和交流阻抗法比较研究了1－苯基－5－巯基四氮唑（PMTA），2－巯基苯并恶唑（MBO）和2－硫基苯并咪唑（MBI）以及复配缓蚀剂（PMM）在Na2S 和HSCH2COOH溶液中对银的缓蚀性能，结果表明，PMM对银具有很好的缓蚀效果，表现出协同效应。     

Revisiting Persistent Indexing Structures on Intel Optane DC Persistent Memory

Persistent indexing structures are proposed in response to emerging non-volatile memory(NVM)to provide high performance yet durable indexes.However,due to the lack of real NVM hardware,many prior persistent indexing structures were evaluated via emulation,which varies a lot across different setups and differs from the real deployment.Recently,Intel has released its Optane DC Persistent Memory Module(PMM),which is the first production-ready NVM.In this paper,we revisit popular persistent indexing structures on PMM and conduct comprehensive evaluations to study the performance differences among persistent indexing structures,including persistent hash tables and persistent trees.According to the evaluation results,we find that Cacheline-Conscious Extendible Hashing(CCEH)achieves the best performance among all evaluated persistent hash tables,and Failure-Atomic ShifT B+-Tree(FAST)and Write Optimal Radix Tree(WORT)perform better than other trees.Besides,we find that the insertion performance of hash tables is heavily influenced by data locality,while the insertion latency of trees is dominated by the flush instructions.We also uncover that no existing emulation methods accurately simulate PMM for all the studied data structures.Finally,we provide three suggestions on how to fully utilize PMM for better performance,including using clflushopt/clwb with sfence instead of clflush,flushing continuous data in a batch,and avoiding data access immediately after it is flushed to PMM.     

Telechelic polymers by living and controlled/living polymerization methods

Telechelic polymers, defined as macromolecules that contain two reactive end groups, are used as cross-linkers, chain extenders, and important building blocks for various macromolecular structures, including block and graft copolymers, star, hyperbranched or dendritic polymers. This review article describes the general techniques for the preparation of telechelic polymers by living and controlled/living polymerization methods; namely atom transfer radical polymerization, nitroxide mediated radical polymerization, reversible addition-fragmentation chain transfer polymerization, iniferters, iodine transfer polymerization, cobalt mediated radical polymerization, organotellurium-, organostibine-, organobismuthine-mediated living radical polymerization, living anionic polymerization, living cationic polymerization, and ring opening metathesis polymerization. The efficient click reactions for the synthesis of telechelic polymers are also presented.