When the armor plate is compared with the tightly arrayed corundum spheres, and penetrated by the same long-rod projectile, we find that the anti-penetration performance of corundum spheres is better than that of the armor plate when the unit area mass is uniform, the penetration depth of the unit energy for long-rod projectiles reduced by 8.73% for average.

Results showed that the stretch recovery,the compression recovery and the unit area mass of fabrics had more influence on the vertical rising size of turn-over collar than the other properties.

Examples show that the piston velocity and compressed-gas property depend strongly on the unit area mass of the piston,σ,and the initial pressure on both sides of the piston ,p0 and p1,but the effect of the sliding friction between the piston and compress tube on the piston motion is very small in the range of sliding friction coefficients from 0.4 to 1.2.

The result showed that the linear correlation lay between particulates numerial concentration, total surface area, mass concentration and particle diameters, and the peak value of airborne particulate concentration lay between 1 and 2 μ m.

(4) For Model MSIS 90, we found that the value of adjusted area mass ratio was 1.09 times that of it's theoretical one, we thought that at the altitude about 120km, the value of density given by MSIS 90 might be less than that of real density.

Balance laws connected with "area" mass and momentum transportation for δ-shocks are derived.

New York area mass transit systems were also set to receive $17.5 million to improve security.

In this paper, a new method to compute the air-drag perturbation of artificial earth satellite is proposed, and the air density model is exponential. The main points are: (1) The orbital eccentricity e is replaced by parameter β, (2) The radicals appeared in the integrand are expanded in terms of Legendre polynomials: Where E is the orbital eccentric anomaly. (3) Based on the properties of legendre polynomial and the definition of Bessel function: The integral results can be written in the form of linear combination...

In this paper, a new method to compute the air-drag perturbation of artificial earth satellite is proposed, and the air density model is exponential. The main points are: (1) The orbital eccentricity e is replaced by parameter β, (2) The radicals appeared in the integrand are expanded in terms of Legendre polynomials: Where E is the orbital eccentric anomaly. (3) Based on the properties of legendre polynomial and the definition of Bessel function: The integral results can be written in the form of linear combination of I_m~*(v). (4) According to the demand that the relative error must be less than 1%, and order of magnitude analysis of terms appeared in the integral results, the simplified computational formulae of the secular term coefficient σ_(22) for semi-major axis a and eccentricity e are obtained as following: Where b is the product of the resistance coefficient C_D and the area-mass ratio s/m; ρ_0~* is the product of exp [-(a(1-e)-a_0(1-e_0)/H)]and ρ_0 which is the air density at the perigee r_0=a_0(l—e_0) of satellite initial orbit; H_1 is the scale height at the same point; and I*_m is the simplified form of I*_m(v). Those formulae are applicable to compute the orbit with any eccentricity. With those formulae, the computational results of satellites with any eccentricity shows: the relative errors for satellite with perigee heights of 160, 250, 400, and 1000 km are no more than 0.08%, 0.16%, 0.21% and 0.72% respectively. The method proposed in this paper can be not only easily extended to the more complicated exponential model of air densi ty, but also used to save storage and machine time as well. Therefore, it is significant both in theory and practice. The effect is obvious.

Design of a turbocharger compressor stage was formulated as a multiobjective nonlinear mathematical programming problem with the objectives of miniming aerodynamic losses and maximizing specific area (mass flow rate / flow path area of impeller inlet). Aerodynamic as well as mechanical constraints were considered in the problem formulation. A prediction method for performances of compressor stage was presented. Examples for maximum efficiency, maximum specific area, and weighted optimum...

Design of a turbocharger compressor stage was formulated as a multiobjective nonlinear mathematical programming problem with the objectives of miniming aerodynamic losses and maximizing specific area (mass flow rate / flow path area of impeller inlet). Aerodynamic as well as mechanical constraints were considered in the problem formulation. A prediction method for performances of compressor stage was presented. Examples for maximum efficiency, maximum specific area, and weighted optimum between efficiency and specific area were given and showed the presented optimization technique is valid and practical.

A new method of calculating exactly Performance parameters of a heavy piston compressor has been investigated in this paper. From the theory of unsteady flow,the processes of the heavy piston motion and the variation of the compressed gas property have been obtained under various circumstances. The numerical method is a development from the operating principle of a heavy piston compressor and the utility program is very important to the design and calibration of a free-piston shock tunnel.Examples show that...

A new method of calculating exactly Performance parameters of a heavy piston compressor has been investigated in this paper. From the theory of unsteady flow,the processes of the heavy piston motion and the variation of the compressed gas property have been obtained under various circumstances. The numerical method is a development from the operating principle of a heavy piston compressor and the utility program is very important to the design and calibration of a free-piston shock tunnel.Examples show that the piston velocity and compressed-gas property depend strongly on the unit area mass of the piston,σ,and the initial pressure on both sides of the piston ,p0 and p1,but the effect of the sliding friction between the piston and compress tube on the piston motion is very small in the range of sliding friction coefficients from 0.4 to 1.2.