The threshold for the coastal system to climate change,over which irreversible degradation will occur,is still beyond our present knowledge,considering human proactive adaptability,and multi-factors with their complex relationship with the deltaic environments.

Whether China should liberalize capital account evokes a lot of controversies, mainly on whether the benefits of capital account liberalization exceed its costs and risks.

As the material basis of life, if the pollution of soilis beyond its selfpurification capability, the ability of soil living will decrease, even die away,which is harmful for human's health, social economy and ecosystem.

At present, when structure designers are doing optimization design, they only consider structure optimization of design phase and initial cost, and don't consider change of structure performance from design to failure and corresponding cost, but structure performance is descending during the structure's service time, and in some cases, the whole maintenance cost during it's service time can exceed initial cost.

The article discusses the laminar boundary layer on the vaporizing surface of liquid hydrogen over which there is a flow of molecular hydrogen.

The theory of short waves assumes that the jump in pressure at the wave front and the region over which the parameters vary are small.

Braking of the gas flow produced by the end currents is determined at two fixed sections of the magnetogasdynamic channel from the value of the isolated shock wave formed in the vicinity of the hemispherical model over which the flow passes.

In [4] an expression is given for the diffusional flux to the surface of a solid ellipsoidal particle over which a uniform Stokes stream flows.

A study is made of the nonstationary laminar boundary layer on a sharp wedge over which a compressible perfect gas flows; the wedge executes slow harmonic oscillations about its front point.

The method of functions of complex variable is used in solving the problem of small amplitude surface waves on water generated by a vibrating side wall, the general formula for the complex velocity is given, and three different types of wall vibrations are discussed in some detail.Two different methods were used for the measurements and recording of surface waves. The experimental results in the case of small amplitude agree well with theory. Some observation and recording were made with large amplitudes. Second...

The method of functions of complex variable is used in solving the problem of small amplitude surface waves on water generated by a vibrating side wall, the general formula for the complex velocity is given, and three different types of wall vibrations are discussed in some detail.Two different methods were used for the measurements and recording of surface waves. The experimental results in the case of small amplitude agree well with theory. Some observation and recording were made with large amplitudes. Second subharmonic vibrations were observed in the surface waves when the driving frequency is above a certain critical value. This phenomenon is yet to be accounted for theoretically.

In the present paper,we study the boundedness and stability of solutions of the following n-dimensional system of differential equations: dx/dt=A(t)x+f(t,x) x(t_0)=x_0 (1.1) where A(t)is a contiouous n×n matrix for t≥t_0≥0 and f(t,x)is a con- tinuous vector function for t≥t_0,x∈D={x||x|

In the present paper,we study the boundedness and stability of solutions of the following n-dimensional system of differential equations: dx/dt=A(t)x+f(t,x) x(t_0)=x_0 (1.1) where A(t)is a contiouous n×n matrix for t≥t_0≥0 and f(t,x)is a con- tinuous vector function for t≥t_0,x∈D={x||x|0 is a certain constant or+∞.Then the solution of(1.1)passing through(t_0,x_0)can be continued to the interval(t_0,t_0+α)and |x(t)|≤y(t) for t∈[t_0,t_0+α In §3,§4,we use the fundamental theorem to obtain some ratiher general criteria for boundedness and stability of solutions of(1.1)which include a series of results concerned [1] [2] [3] [6],and in this manner one may see the internal relation between these results.In this paper we also come to a similar result obtained by Stokes [16]which relies on a fixed point theorem for locally convex topological linear space due to Tychonoff.

The effect of the monochromaticity of relativistic electron beam's energy on the small signal gain of free electron lasers is analyzed. For a certain pumping field, there is a critical energy divergency, over which the small signal gain will become negative. The shorter the wavelength and the longer the magnification length, the higher is the requirement of energy monochromaticity of electron beam for laser amplifiers. But the requirement of monochromaticity of electron beam for laser oscillators is much lower....

The effect of the monochromaticity of relativistic electron beam's energy on the small signal gain of free electron lasers is analyzed. For a certain pumping field, there is a critical energy divergency, over which the small signal gain will become negative. The shorter the wavelength and the longer the magnification length, the higher is the requirement of energy monochromaticity of electron beam for laser amplifiers. But the requirement of monochromaticity of electron beam for laser oscillators is much lower.