纤维共晶生长界面前沿三维扩散场解析

修正Ｊａｃｋｓｏｎ和Ｈｕｎｔ关于在垂直生长方向截面上溶质扩散各向同性假设，求解三维Ｌａｐｏｌａｃｅ方程，获得纤维共晶生长界面前沿三维稳态扩散场，并证明Ｊａｃｋｓｏｎ和Ｈｕｎｔ的二维模型是实际生长的二维简化和一阶近似，并用丁二腈（ＳＣＮ）一梓脑（ＣＡＭ）纤维共晶系统计算生长界面前沿溶质分布。     

A newly robust controller design for the position control ofpermanent-magnet synchronous motor

A robust controller which is designed by employing variable-structure control and linear-quadratic method is presented for a permanent-magnet synchronous motor (PMSM) position control system. It is to achieve accurate control performance in the presence of plant parameter variation and load disturbance. In addition, it possesses the design flexibility of the conventional state feedback control. It is applied to the position control of a PMSM. Simulation and experimental results show that the proposed approach gives a better position response and is robust to parameter variations and load disturbance     

Resonant snubber-based soft-switching inverters for electricpropulsion drives

This paper summarizes recently developed soft-switching inverters and proposes two possible options for electric propulsion motor drive applications. The newly developed soft-switching inverter employs an auxiliary switch and a resonant inductor per phase to produce a zero voltage across the main switch, so that the main switch can turn-on at the zero-voltage condition. Both the auxiliary switch and the resonant inductor are operating at a fractional duty and, thus, are small in size as compared to the main inverter circuit components. Operation modes in a complete zero-voltage switching cycle for the single-phase soft-switching inverter are described in detail, with graphical explanations. The circuit operation was first verified by a computer simulation, and then further tested with a 1 kW single-phase and a 100 kW three-phase inverter. Both simulation and experimental results are presented to show the superior performance in efficiency improvement, EMI reduction and dv/dt reduction of the proposed soft-switching inverters     

铁电体尺寸对其开关特性的影响

应用铁电体极化反转的Orihara Ishibashi理论 ,讨论了圆形铁电薄膜和球形铁电体的开关电流以及开关时间对系统尺寸的依赖性。数值计算表明 ,不论是二维还是三维铁电系统 ,其铁电畴反转过程中产生的开关电流都随系统尺寸减少而下降 ,开关时间随系统尺寸减少而缩短     

FEATURE SOLID MODELING TOOL SYSTEM:FSMTS

In conformity with the principle of Design for Manufacture,feature-based design strate-(?)es have been developed.As the“feature”is relevant to the“macro process plan”and“macro NCprograms”,obviously,“feature”is beyond the power of conventional solid modellers.Neverthe-less,substantial breakthrough has not been made in the solid modeling field,except“feature at-taching”or“feature recognizing”methods have been taken on.In this paper,the theory,concepts,system architecture,and algorithm principles of solid modeling tool system have beenrepresented.The practice of Feature Solid Modeling Tool System (FSMTS) developed atHuazhong University has proved that the tool may be a new foundation of Feature-Based Design.     

掺杂染料的向列相液晶微粒材料的非线性光学研究

对布满液晶微粒的聚合物(PDLC)进行了简并四波混频及光学双稳态的研究,并在文中对相关的PDLC中的分子重取向和热效应的非线性光学效应进行了讨论.     

片式多层电容电阻复合元件的研制

采用低温共烧陶瓷(LTCC)技术将电容、电阻元件集成在多层陶瓷基板里,构成了一种新型的片式多层复合元件,并研究了其制造工艺性能和频率特性。结果表明,片式多层电容电阻复合元件制造工艺适合批量化生产,并为片式多层LC滤波器、LTCC基板及器件的研发提供了极好的参考价值。     

Continuous Separation of Inclusions from Aluminum Melt Flowing in a Circular Pipe using a High Frequency Magnetic Field

The continuous separation of inclusions from aluminum melt flowing in a circular pipe using a high frequency magneticfield was investigated both theoretically and experimentally The separation efficiency was calculated based on thetrajectory method and compared with experimental results. It is found that the separation efficiency is a functilnondimensional parameters t_i·d_p~2B_e~2/μ_fμ_eα~2 and α/δ.The effective way to improve the separation efficiency is to increasethe effective magnetic flux density and decrease the pipe radius. and the value of α/δ should be kept about 2 in orderto obtain the optimum separation efficiency.     

新理念催生新结构——IMTS2006观后感之三

自上世纪90年代以来,机床出现了许多新结构,其中绝大多数没有知识产权问题,也即没有专利的约束。在需要时,任何人均可采用。每一种结构均来自