Table of Content

30 June 1987, Volume 8 Issue 2

Previous Issue    Next Issue

Paper

A Gasdynamic Study on Grenades Fired by Blank Ammimitions

Jin Zhiming,Son Ming

1987, 8(2):  1-9.  doi:10.3969/j.issn.1000-1093.1987.02.001

Asbtract ( )   PDF (9681KB) ( )  

References | Related Articles | Metrics

A set of quasi-one-dimentional gasdynamic equations of interior ballistic two-phase flow is presented，based on an analysis of the experimental re?sults of firing grenades by blank ammunition. A complete method of calcu?lation is described with difference grids on whicb. variables are located un- conforrnably and difference form with the second-order accuracy. A program is developed using Fortran 77. Some comparisons between theoretical and experimental results show that the mathematical-physkal model established is reasonable for predicting the in terior ballisticphexiomena. of firing grenades.

Study of Lagrange's Profclem Using the Ballistic Method and Some of Its Applications

Qiu Wenjian,Chen Jianzhong

1987, 8(2):  10-19.  doi:10.3969/j.issn.1000-1093.1987.02.002

Asbtract ( )   PDF (9801KB) ( )  

References | Related Articles | Metrics

In this paper the general analytical solution of lagrangeˊs problem is derived through the hydro-dynamic fundamental equation. It is found that there exists an approximate similar criterion that is adequate for it. Based on tke sets of P-t curves actully measured in gun bore the authors have obtained a linear function of l/lc to express the ratio of Pt/Pd appro-ximately. The interior ballistic solving method has shown that such a so?lution using this Pt/Pd function gives higher precision than is obtainable using lagrangeˊs approximation.

Two Step Pressufe Oscillations in capillary Rheology of Two Polyethylenes

Li Hongyiao

1987, 8(2):  20-26.  doi:10.3969/j.issn.1000-1093.1987.02.003

Asbtract ( )   PDF (7955KB) ( )  

References | Related Articles | Metrics

The phenomena of two step pressure oscillations in capillary rheology of HDPE Alathon and LDPE Lotrex and the typical curves of them are presented, The features of the phenomena and the factors liaving effects on them are described, Finally a brief discussion on the experimental re-sults is given,

The Synthesis and Electronic Structure of 1, 3，3,5，7，7-Hexanitro-1,5-Diazacyclooctane

Chen Boren, Xiao Heming, Li Yongfu

1987, 8(2):  27-32.  doi:10.3969/j.issn.1000-1093.1987.02.004

Asbtract ( )   PDF (6369KB) ( )  

References | Related Articles | Metrics

This paper describes the synthesis of a new energetic compound 1,3，3. 5, 7, 7-hexanitro-l, 5-diazacyclooctane. We give its electronic structure, by computation，in experimental configuration，by the SCF-CNDO/2 met?hod with Slaterˊs and standard orbital exponents . The computed results are in accordance with the experimental facts based on its thermal decom?position and the mass spectra.

The M T.F.of Human Visual System With Monochromatic Light for Two Age Groups

Wu Xinnian, Chen Yijun, Du Lianfang

1987, 8(2):  33-37.  doi:10.3969/j.issn.1000-1093.1987.02.005

Asbtract ( )   PDF (5358KB) ( )  

References | Related Articles | Metrics

Contrast thresholds of human visual system were measured with mo?nochromatic gratings for two age groups utilizing an apparatus developed in the laboratory, taken as a function of spatial frequencies. The results show that the contrast threshold curves of young people for a set of gra?tings illuminated constantly by various monochromatic light are similar to each other at a luminace of 5 cd/m2。The contrast thresholds for yellow gratings are the lowest and the next one is for blue gratings. For white light gratings with two levels of luminances 10, 100cd/m2,the contrast thre?sholds of young people are lower than that of middle-aged oyer a wide rang of spatial frequencies, except for lower frequencies at a luminance of 10 cd/m2 .

On the Jump of Lined Spherical Shell

Cheng Zhaoxiong

1987, 8(2):  38-45.  doi:10.3969/j.issn.1000-1093.1987.02.006

Asbtract ( )   PDF (8571KB) ( )  

References | Related Articles | Metrics

Structures with thin lined are widely used in enginering, In the lined thin shells, instability under thermal sterss may occur. The problems which define the critical value and buckling form of the thin shell are concer?ned. This paper will state the distinction of the stability of general struc?tures and those structures such as. lined spherical shell. In the later case the influence of disturbance force must be considered. Whether jump will appear and at which state it will stand depends upon the value and form of the disturbance force. The nigher the thermal stress the larger the dis?turbance force which will lead to the jump，i. e. the more difficult the instability of the shell to occur. Moreover, the jump is not sensitive to the imperfection of the shell itself. The conclusion of this paper is suitable for all lined thin shells winch have non-negative Gauss curvature.

Optimal Assigumeiit of Fire Power When Heavy Weapons Fire at Large Area Target

Pan Chengpan

1987, 8(2):  46-55.  doi:10.3969/j.issn.1000-1093.1987.02.007

Asbtract ( )   PDF (9560KB) ( )  

References | Related Articles | Metrics

The problem of the optimal assignment of fire powel when heavy weapons fire at small area target has been resolved by A. N. Kolmogorov and his stu?dents. When the target area is large, this problem used to be discussed under the condition of uni-form assignment of fire power. In this paper, it is shown that the uniform assignment of fire power is not optimal in the case of large area target and some available approximate schemes of fire power assignment are given.

Classical, Fiducial and Bayesian Limits for One-Sided ReliaDinty of Normal Distribution

Zhou Yuanquan

1987, 8(2):  56-62.  doi:10.3969/j.issn.1000-1093.1987.02.008

Asbtract ( )   PDF (7126KB) ( )  

References | Related Articles | Metrics

In this paper，the exact Bayesian limits taking the conjugated prior distrib?ution, Classical limits and Fiducial limits for one-sided reliability of the nor?mal distribution are given. They can be expressed by the nonlinear equation for the Cdf (cumulative distribution function )of generalized noncentral t-distribu- tion. When the nonimformative prior distrbution on the normal parameters is tak?en, the Bayesian limits are equal to the Classical and Fiducial limits. In order to decrease the computation time and for the convenience of engineering app?lication,the approximate Bayesian and Classical limits 这re given.

Experimental Techniques and Analysis

High Speed, Multiple-Frame Transient Interferometer in Its Apjjlications to Rocket Engine Exhaust Plumes

He Anzhi, Yan Dapeng, Ni Xiaowu, Lai Tianshu

1987, 8(2):  63-66.  doi:10.3969/j.issn.1000-1093.1987.02.009

Asbtract ( )   PDF (5137KB) ( )  

References | Related Articles | Metrics

The paper presents the operational principles of high speed, multiple- frame transient interferometer in the visualization of flow field. The inter—ferogram of serial-time-resolution interferograms for flow field processes can be taken with it. Used in the visualization of exhaust plumes of a rocket engine，multiple-：frame interferograms of the shock wave development processes and of the near field structure can be obtained. It provides power?ful experimental means for studying the fundamental characteristics of the whole flow field,

Research Notes

UV Photo Electrnic Method for the Measurement of MCP'S Gain

Tian Jingquan, Zhu Baoren, Jiang Delong, Wu Kui

1987, 8(2):  67-71.  doi:10.3969/j.issn.1000-1093.1987.02.010

Asbtract ( )   PDF (5130KB) ( )  

References | Related Articles | Metrics

An ultraviolet photo-electronic method for the measurment of MCPˊS electron gain is intrduced in the paper. The experiment set-up procedure and some results are given. The advantages of the method are explaned and des- cribed，pointing out the possibility of realizing MCPˊscomprehensive param eters test，and the image tube simulation simultaneously by the method proposed.

A Physical Explanation for the Dynamic Stability of Pirbjeetiles

Song Peiji

1987, 8(2):  72-75.  doi:10.3969/j.issn.1000-1093.1987.02.011

Asbtract ( )   PDF (4409KB) ( )  

References | Related Articles | Metrics

This paper seeks to explain physically how the Magnus and damping moments cause the dynamic instability of tne projectiles, in accordance with the force system applied on the projectile, and its state of motion.