半导体厂超净供气系统

介绍了集成电路制造用的电子气体中粒子控制规范,供气系统用的材料及其处理技术,供气管路和配件技术,粒子过滤及计数技术。     

Developing a Simple NMR Interface: WWNMR

We have designed and implemented an automated walkup NMR computer application for use by synthetic chemists. The Wyeth Walkup NMR (WWNMR) application is a TCL/TK graphical user interface front-end to Varian's NMR automation routines. The key feature of WWNMR is that the chemists are isolated from the spectrometer's control program (VNMR) and only enter information to WWNMR windows for a sample to be run. The resulting data can be printed out on paper, or stored on disk for easy access by all users at their desktops. Proton and carbon NMR experiments are available. An overview of the WWNMR application will be presented.     

ADAPTIVE CONTROLLER AND ITS APPLICATION IN FORCE SYSTEM OF ASYMMETRIC CYLINDER CONTROLLED BY SYMMETRIC VALVE

Partial pressure, system vibration and asymmetric system dynamic performance exit in asymmetric cylinder controller by symmetric valve hydraulic system. To solve this problem in the force control system, model reference adaptive controller is designed using equilibrium point stability theory and output error equation polynomial. The reference model is selected in such a way that it meets the system dynamic performance. Hardware configuration of asymmetric cylinder controlled by asymmetric valve hydraulic system is replaced by intelligent control algorithm, thus the cost is lowered and easy to application. Simulation results demonstrate that the proposed adaptive control sheme has good adaptive ability and well solves asymmetric dynamic performance problem. The designed adaptive controller is fairly robust to load disturbance and system parameter variation.     

ADAPTIVE RIGID-PLASTIC MESHLESS GALERKIN METHOD AND ITS APPLICATION IN ANALYSIS OF EXTRUSION PROCESSES

Under the hypothesis of the rigid-plastic material,specific efforts are placed on the deve-lopments of the key simulation techniques of the meshless Galerkin method because of the complexity of the deformation process as well as the generality and atomization of the simulation procedures for non-steady state large deformation plastic processes,therefore,an adaptive rigid meshless Galerkin method is developed. The influence domain control method is used in the least square approximation by dynamic evaluation of the magnitude of the influence domain and the effective control of the amount and the positions of the points in the least square approximation in order to improve approxi-mation precision. The amount of the Gauss integration points in the discrete domain is maintained in a considerable magnitude in order to ensure the integration precision in the discrete domain. The length of the frictional boundary of the plastic deformation process may be getting longer when its deforma-tion is getting severe. Thus,the densities of the boundary points of some places get lower. The adap-tive boundary points setting method is employed to improve the approximation precision of the boundary points and enhance the constraint of the boundary condition by adaptive control of boun-dary point density. Some typical extrusion processes are analyzed,detail simulation results such as the deformation field,velocity field,effective strain field,effective strain rate field,the volume loss curve and load-stroke curve are obtained. The effectiveness of the method developed is demonstrated and the precision of the meshless simulation is proved by overall comparison with the results obtained by using the commercial software deform.     

Reinforced thermoplastic pipe using recycled PET reinforcement

Abstract

The present study describes the results of a pilot study to carry out the initial development and testing of a new class of high-pressure all thermoplastic pipe, using recycled PET as reinforcement. A prototype pipe design has been manufactured and initial qualification testing carried out demonstrating a new high added value product application for recycled materials.     

MULTI-LAYER PIEZOELECTRIC ACTUATOR AND ITS APPLICATION IN CONTROLLABLE CONSTRAINED DAMPING TREATMENT

A kind of novel multi-layer piezoelectric actuator is proposed and integrated with control- lable constrained damping treatment to perform hybrid vibration control.The governing equation of the system is derived based on the constitutive equations of elastic,viscoelastic and piezoelectric materials,which shows that the magnitude of control force exerted by multi-layer piezoelectric actua- tor is the quadratic function of the number of piezoelectric laminates used but in direct proportion to control voltage.This means that the multi-layer actuator can produce greater actuating force than that by piezoelectric laminate actuator with the same area under the identical control voltage.The optimal location placement of the multi-layer piezoelectric actuator is also discussed.As an example,the hybrid vibration control of a cantilever rectangular thin-plate is numerically simulated and carried out experimentally.The simulated and experimental results validate the power of multi-layer piezoelectric actuator and indicate that the present hybrid damping technique can effectively suppress the low fre- quency modal vibration of the experimental thin-plate structure.     

PLC在转炉风机煤气回收中的应用与研究

介绍转炉一次除尘风机及煤气回收系统中应用的可编程控制器(简称PLC)系统，对系统调试生产过程中遇到的几个问题进行分析与研究，并提出建议和改进方法。     

通风在粮食储藏中应用的探讨

叙述了通风技术在粮食储藏中的作用及其在粮食储藏中的应用情况，对粮食通风方式及风网布置形式进行了比较分析，并提出了在粮食储藏中应用通风技术的几点建议。     

Fabrication of dc–dc converter using nanocrystalline Mn–Zn ferrites

Abstract

The microwave–hydrothermal method has been successfully used for synthesis of nanocrystalline Mn–Zn ferrites which are used for high frequency applications. The nanopowders were characterised using X-ray diffraction and TEM. The nanopowders were annealed using microwaves at 600°C/10 min. The frequency dependence of dielectric constant ?′ was measured in the range from 10 Hz to 1·3 GHz, and initial permeability μ _i was measured in the range from 10 Hz to 1 MHz. The total power loss was measured at 100 kHz and 200 mT on the annealed samples. Conductor embedded ferrite transformers were fabricated, and output power P _o, efficiency η and temperature increase ΔT were measured at sinusoidal voltage of 25 V with frequency 1 MHz. The transformer efficiency η was found to be high, and surface rise of temperature ΔT is very low.     

Development of nanocrystalline Mn–Zn ferrites for forward type DC–DC converter for switching mode power supplies

Abstract

Nanocrystalline Mn–Zn ferrites have been successfully synthesised using the microwave–hydrothermal method for high frequency applications. The nanopowders were characterised using X-ray diffraction (XRD) and transmission electron microscopy (TEM). They were annealed using the microwave sintering method at 900°C for 20 min. The frequency dependence of the dielectric constant ?′ and and the initial permeability μ _i were measured in the range 10 Hz to 1·3 GHz. The saturation magnetisation M _s and coercive force H _c were obtained using a vibration sample magnetometer (VSM) in the field of 20 kOe. The total power loss was measured in the range of 100 kHz to 1 MHz with a flux density of 50 mT on the annealed samples. Conductor-embedded ferrite transformers were fabricated and the output power P _o and efficiency η were measured; 80% efficiency was obtained for a forward-type multilayered transformer.