Table of Content

31 December 1998, Volume 16 Issue 4

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Articles

One Type of B₁₄ Mode Standing Wave Ultrasonic Motor Using Ring Plate

LIU JINGQUAN, WU BODA, YANG ZHIGANG, CHENG GUANGMING

1998, 16(4):  379-384. 

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A new type of standing -wave ultrasonic motor which consists of a ring plate with projections is only excited by one group of piezoelectric ceramics. The tops of the projections form the oblique displacement motion, so the projections provide the driving force for the motor. The driving principle of this type of motor is introduced. The curves about the main dimensions of the elastic body versus its natural frequency of the vibrator by FEM are given. The B₁₄ mode natural frequency of the vibrator is also calculated. Moreover the characteristics of the prototype in speed are measured and its feasibility is verified.

Application of the Hidden Curve Removal Algorithm in Interference Detecting of 5 -Axis NC Machining

YANG YONGSHENG, ZUO DUNWEN, WANG MIN, WANG LENGGAN

1998, 16(4):  385-391. 

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Proposed in this paper an approach that the hidden curve removal algorithm is used to determine the 5-axis millable areas of interference-free, which reduces the accessibility problem of 5-axis milling using a flat-end tool to a 3-axis accessibility problem based on the Gaussian mapping. That is, using the M^S mapping of a point q above surface S(u,v) and of constraining surfaces K(s,t), the surface S(u,v) regions that are hidden by constraining surfaces K(s,t) can be computed in the orthogonal space D, then the domain of the surfaces S(u,v) that can be milled using 5-axis flat-end tool without interference to constraining surface K(s,t) can be calculated by trimming away the hidden regions Back

An Optimization Method for the Direct Position Kinematic Problem of a General Parallel Manipulator

LIU DONGSHENG, GONG ZHENBANG, WANG QINQUE

1998, 16(4):  392-396. 

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This paper deals with the direct position kinematic problem of a general pa rallel manipulator using an optimization method. Without complex formular deduction and without restricting starting -point, this method is effective to all parallel manipulators. This new theoretical result is confirmed by numerical examples.

A Novel Associative Memory Based on the Architecture of Recurrent Correlation Associative Memory

WANG BAOYUN, HE ZHENYA, YANG LÜ XI

1998, 16(4):  397-402. 

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The main difference between the recall rule of recurrent correlation associative memory and that of Hopfield network is that RCAM operates a nonlinearity upon the correlations between input and stored patterns. In this paper, it proposes to improve the performance of RCAM by truncating the insignificant correlations, produce a novel associative memory based on the architecture of RCAM, noted as TRCAM. The theoretical analysis shows that the method raises the signal-to-noise ratio greatly. The simulations illustrate that this model enjoys a high capacity Back

Neural Network Beamforming Technique for Cyclostationary Signals

CHEN YUXIN, HE ZHENYA

1998, 16(4):  403-408. 

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Most of the communication signals have the cyclostationary character. SCORE is an excellent algorithm based on cyclostationary. However, main disadvantage of this algorithm is the huge calculation of the matrix compution and the matrix inverse compution. A neural network beamforming technique which can solve this problem successfully is proposed in this paper. The experiment results have shown that this algorithm has better performance and can reject noise strongly.

The Research of FM Signal Demodulation Based on DSP

YANG PING, SHENG ZHIJIE

1998, 16(4):  409-415. 

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Two methods of FM Signal demodulation, phase shift discrimination and looking up arcsine table, are discussed and verified by using TMS 320C50 DSK. Experimental results show that these methods have a good effect on the demodulation under certain conditions.

Study of Displace Matrix in Asynchronous Displace System

CAO XIUYING

1998, 16(4):  416-420. 

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This paper analyses the displace effect of asynchronous displace matrix, and shows how to select the displace matrix and estimate the effective key-space.

Application of Volterra Series to Intermodulation Distortion Simulation of a Beeper High-Frequency Amplifier

LIAO XIAOPING, WEI TONGLI

1998, 16(4):  421-426. 

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This paper studies how to analyze a weakly nonlinear circuit using Volterra series, make a nonlinear Volterra model of a high-frequency transistor, and calculate the third order intermodulation in a Beeper high-frequency amplifier. This way can be used in designing other weakly nonlinear circuits in order to have highly linear high frequency amplifier.

Direct Numerical Calculation For Permanent Magnetic Circuit

HU HONGMEI

1998, 16(4):  427-433. 

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In this paper, a method of direct calculation using FEM is described for the permanent magnet design, including proceesing method of calculating model, work zone, variable element, automatic adjusting of network and interchanging of data. The calculated results agree with the measurements.

Study on the Magnetic Anisotropy and Magnetic Viscosity of γ-Fe₂O₃ Powders

HOU DENGLU, NIE XIANGFU, TANG GUIDE, LUO HELIE

1998, 16(4):  434-442. 

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The granular γ-Fe₂O₃ powders, the acicular γ-Fe₂O₃ and CoFe γ-Fe₂O₃ powders are prepared. The particle shapes and mean particle sizes of the samples are determined by transmission electron microscopy. The phases are determined by X ray diffraction. By using vibrating sample magnetometer, the magnetic parameters are measured at different temperatures. By the law of approach to saturation, the effective magnetic anisotropy constants of granular γ-Fe₂O₃ powders at different temperatures are obtained. By using magnetotorquemeter, the effective magnetic anisotropy constants of acicular γ-Fe₂O₃ and CoFe γ-Fe₂O₃ powders are measured. It is found for the first time that variation tendency of effective magnetic anisotropy of granular γ-Fe₂O₃ with the temperature is about the same as that of the magnetic anisotropy with the temperature. The fluctuation field H_f and the activation volume of the samples at different temperatures are measured. The theoretical expression of activation volume is derived, For the granular γ-Fe₂O₃ powders, the calculated activation volumes at different temperatures are consistent with the experimental ones. But for acicular γ-Fe₂O₃ powders, the calculated activation volumes at different tempera tures is different from the experimental ones. It is found experimentally, for the first time, that magnetization reversal of granular γ-Fe₂O₃ at different temperatures is close to the uniform rotation.

Spatially Integrating Fiber Optic Strain Sensor For Vibration Monitoring In Smart Structure

HAN LEI, A. VOLOSHIN, J. COULTER

1998, 16(4):  443-450. 

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During the present study, a spatially integrating fiber optic sensor (FOS) was used for vibration monitoring. It is based on that the optimal placement of the sensing element can be sought by using a prior knowledge of the mode shapes of the structure. The applicability of this approach to polarimetric optical fibers is described. The acquired integrating FOS signal was used to sense and control the vibration of an electrorheological structure subjected to external excitations.

Research on Measuring the Diameter of Well by Utilizing Sideways Look Bore-Hole TV System

WANG DEFU, YU JINGLIANG, SUN DINGJUN

1998, 16(4):  451-456. 

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Comply with the constant principle of angle of view of sideway look bore-hole TV system, the diameter of well is measured directly and simply by utilizing the television system, which is analyzed theoretically and at the same time has been proved through experiments.

Real Time Performance Evaluation for Dynamic Scheduling Algorithm

LEI HANG, XIONG GUANGZE

1998, 16(4):  457-462. 

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On the basis of the dynamic scheduling algorithm of real time multitasking and the factors that be closely concerned with real time performance, a evaluation model is proposed. The model can point out that which tasks will produce time out fault and estimate the probability.

Performance Analysis for a Regenerated Air Heat Pump Cycle with the Consideration of Heat Transfer Effect

CHEN LINGEN, NI NING, LIU JIUQI, SUN FENGRUI, GONG JIANZHENG

1998, 16(4):  463-468. 

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Performance analysis of a real heat pump is carried out using the methods of finite time thermodynamics. Accounting to the irreversibilities of heat resistances in the hotand cold-side heat exchangers and the regenerator and the irreversible compression and expansion losses in the compressor and expander, this paper derives the analyticalrelation between heating load, COP and the pressure ratio for an irreversible closed regenerated air heat pump coupled to variabl temperature heat reservoirs. Detailed numerical examples are given also.

New Variants of the Generalized Synchronous and Asynchronous Parallel Matrix Multisplitting Relaxation Methods

BAI ZHONGZHI, SU YANGFENG

1998, 16(4):  469-478. 

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New variants of the existing synchronous and asynchronous parallel matrix multisplitting forward and backward relaxation methods for parallely solving the large sparse system of linear equations on the SIMD and MIMD multiprocessor systems are proposed, and their convergence theories are established under the ordinary conditions.

The Construction of the Efficient Points Set for 1/r,p_j≡1/L_max with Controllable Due Dates

SUN SHIJIE, R. J. KIBET

1998, 16(4):  479-485. 

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This paper considers the machine sequencing problem 1/r,p_j≡1/L_max with controllable due dates.Taking L_max as F₁ and the total delaies of due dates as F₂,for the minimizing the F₁ and F₂ simultaneously,the paper constructs a pseudopolynomial time algorithm for finding out its efficient point set.

Design Principles of Moment Actuator Vibrating Systems

SU QITAI, QIU SHUYE

1998, 16(4):  486-490. 

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In this paper,the equivalent circuit method is used in analyzing the performance of the vibrating system of the moment actuator,and the relations are given among moment,system parameters and load,and it's correctness is attested experimentally.A type of large moment actuator is designed to improve the low frequency performance.It is shown that our calculated results agree with the experimental ones.

A Microstrip Isolator in Ka Band

ZENG SHENGQUAN, CHEN JUNLIAN, FENG SHUANGJIU

1998, 16(4):  491-494. 

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A microstrip isolator in Ka band,which has a advantage of utilizing soft substrate to fabricate devices is described in this paper.The ferrite disk can be embeded into the hole of soft substrate conveniently.The forward loss with less than 1 2dB and the backward loss with greater than 20dB over a 2GHz absolute bandwidth can be achieved with this device configuration.

Relationship between Reference Value of Chinese Healthy Adult and Young People's Whole Blood Contrast Viscosity and Geographical Factors

GE MIAO

1998, 16(4):  495-498. 

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In order to supply a basis for uniting the reference value standard of Chinese healthy adult and young people's whole blood contrast viscosity,a research is made about relationship between the reference value and five geographical factors.It is found that altitude is the main factor affecting this reference value.As the altitude increase gradually,the reference value also increase gradually,the correlation is quite obvious.Applying the method of mathematical regression analysis,two regression equations are given out.If geographical values are obtained in some areas,the reference value of Chinese healthy adult and young people's whole blood contrast viscosity of this area can be reckoned using regression equations.