JOURNAL OF BEIJING INSTITUTE OF TECHNOLOGY

On Univalent Functions in Multiply Connected Domains

Yan Weiqi

1994, 3(2): 99-113.

[Abstract](204)

Abstract:
The present article is an account of results on univalent functions in multiply connected domains obtained by the author. It contains two rery simple proofs of Villat's formula; Schwarz's formula, Poisson's formula and Poisson-Jensen formula in multiply connected domains; the differentiability theorem with respect to the parameter of analytic function family containing one parametric variable on multiply connected domains; variation theorem and parametric representation theorem of univalent functions in multiply connected domains; the solution of an extremal problem of differentiable functionals.

Modelling and Solution of a Ablation-Transpiration Cooling Control Systems

Guo Baozhu, Hao Yong

1994, 3(2): 114-121.

[Abstract](282)

Abstract:
A controlled model of thermal shield of ablation with trapspiration cooling is develoed. The existence and uniqueness of the classical solution can be obtained by Friedman and Jiang's methods. The positivity of the solution is proved and the conditions for the coolant flux under which the abladtion process will complete in finite time are also determined. Finally, we show the existence of critical coolant flux beyond which the ablation material begin melting.

On the Motion of Controllable Mechanical Systems Having Variable Mass

Zhu Haiping, Wu Huibin, Mei Fengxiang

1994, 3(2): 122-130.

[Abstract](237)

Abstract:
The differential equations of motion of a comtlaint system with parameters and variable mass, of a system with variable mass and servo constraints and those for the control problem on the forced motion of constraint systems with variable mass are given respectively. Finally, an example is presented.

Nonequilibrium Statistical Physics Subject to the Anomalous Langevin Equation in Liouville Space

xing xiusan

1994, 3(2): 131-143.

[Abstract](149)

Abstract:
Considering that thermodynarmic irreversibility and hydrodynamic equations can not be derived rigorously and unifiedly from the Liouville equations, the anomalous Langevin equation in the Liouville space is proposed as a fundamental equation of statistical physics. This equation reflects that the law of motion of particles obeying reversible, deterministic laws in dynamics becomes irreversible and stochastic in thermodynamics. From this the fundamental equations of nonequilibrium thermodynamics, the principle of entropy increase and the theorem of minimum entropy production have been derived. The hydrodynamic equations, such as the generalized Navier-Stokes equation and the mass drift-diffusion equation etc. have been derived rigorously from the kinetic kinetic equation which is reduced from the anomalous Langevin equation in Liouville space. All these are unified and self consistent. But it is difficult to prove that entropy production density σ can never be negative everywhere for all the isolated inhomogeneous systems far from equilibrium.

Synthesis and Characterization of Peralkylated β-Cyclodextrins Used as Gas Chromatographic Stationary Phasest

Dai Rongji, Fu Ruonong, Feng Zongcai, Zhou Wei

1994, 3(2): 144-154.

[Abstract](167)

Abstract:
Six peralkylated β- cyclodec\xtrins used as capillary gas chromatographic stationary phases were prepared and characterized by differential by differential scannning calorimetry(DSC) and pyrolysis gas chromatography (PyGC). The DSC profiles illustrated that the peralkylated β-cyclodextrins synthesized possess the supercoooled state and the glass state below their melting point The PYGC results showed that the long-chain alkylated β-cyclodextrins are more thermostable than the short-chain. one All ofthese peralkylated β-cyclodextrins are suitable for use as capillary column gas chromatographic stationary phases,which can easily be coatal on the fused silica capilary columns and have nice chromatographic retention behaviour. For example, the capillary colunns coated with these materials can excellently separate three methylphenol isomers and six dimehylphenol isomers.

Separation of Nucleotides in Swine Tissues Using Capillary Zone Electrophoresis

Gu Junling, Liu Yu, Fu Ruonong, Lu Hongjun, Zhang Yanwan

1994, 3(2): 155-161.

[Abstract](166)

Abstract:
Capillary zone electrophoresis has been applied to the analysis of nucleotides. The effects of buffer concentration. pH and other operating conditions on the separation were investigated and optimized. By using the method, separation and identification of nuclotides in swine tissues were completed.

A Computer-Controlled Polishing Machine

Xin Qiming

1994, 3(2): 162-169.

[Abstract](264) [PDF 368KB](3)

Abstract:
Describes a computer controlled polishing machine utilizing a small polisher with specified movement to figure optical surfces having strict dimensional requirements. The system is especially applicable in figuring aspherical surfaces, beginning with the best fit sphere if the departure from the desired surface is not large. An interferometric measuring system is desiigned to form a closed loop control during processing.

Advanced Digital Techniques and Tendencies in the Development of Modem Digital Satellite Broadcasting

Dong Lizhen

1994, 3(2): 170-175.

[Abstract](125)

Abstract:
The fundamental aspects of digital broadcasting are its service flexibility and power savings, which make all-digital satellite broadcasting a viable and economic propositon compared with analog broadcasting. Tendencies in the development of digital television broadcasting are: (1) Stereophonic or two-language sound transmission with television in existing analog TV system, (2) Digital direct satellite broadcasting (D-DBS); (3)Digital high definition television (HDTV) Broadcasting.

The Development of Dynamic Compliant Wrist for Robots

Zhang Jianmin, Chen Yusheng

1994, 3(2): 176-182.

[Abstract](211)

Abstract:
Based on an analysis of the relative shaft-to-hole position and attiude errors, as well as of the mechanics and Kinematics in the process of automatic assembly of industrial robots, the paper studies the principle of construction of dynamic wrists. Type I-3 and Ⅱ-6 dynamic compliant wrists have been designed and made. Prblems in the production of compliant elements and the connection between compliant elements and wrists were also solved. A study on the results of tests of the function of two kinds of dynamic compliant wrists shows that the dynamic compliant wrist's compliancy function can be improved by adding metallic materials having higher longitudinal and transverse rigidity into the softer elstomer. And the design Principle is proved to be feasible and practicable. It can be expected that the use of dynamic compliant wrist will greatly lower the technical requirements of the shaft-hole assembly and the requirements in the resetting accuracy.

Fault Diagnosis of Mechanical Equipments Through Spectrometric oil Analysis for Worn Off Metallic Elements

Wang Wenqing, Wan Yaoqing, Ma Lu, Wan Xiaodong

1994, 3(2): 183-192.

[Abstract](155)

Abstract:
In the fault prediction of mechanical equipments through spectromectric oil analysis for worn off debris, a method for the determination of the limiting value of wear is proposed and discussed. In order to diagnose the impending failure and to predict the fault modes and locate the fault spots, a comprehensive approach is studied and outlined on the basis of methods of discriminative analysis and fuzzy logic. A fault diagnosis expert system OAFDS developed by the authors for the nonitoring of working conditions of the ND5 locomotive diesel engine Nd5 is briefly introduced.

1994 Vol. 3, No. 2