奇摄动非线性边值问题

The singularly perturbed nonlinear boundary value problems are considered. Using the stretched variable and the method of boundary layer correction,the formal asymptotic expansion of solution is obtained. And then the uniform validity of solution is proved by using the differential inequalities.     

Separation of mixed gases through porous polymeric membranes

The separation of a gas from a two component gas system was studied both theoretically and experimentally. Helium and argon as an inorganic gas pair, ethylene and butane as an organic gas pair, and air were used. The theory based on the free molecular flow could not be applied to all the combinations of the gases experimentally studied. Experiments showed that the permeability coefficient of each component in the mixture was very close to that of each single component, when the pressure in the low pressure side became zero, but those of the mixture approached one another rapidly as the pressure increased. In the case of the separation of one inorganic gas from another, there exists most suitable pressures both in the high and low pressure sides for the most efficient separation, as considered from the selectivity and permeability. In the cases of the mixed organic gases and the organic-inorganic gas combination, a rather high separation efficiency is expected for a very high pressure on the high pressure side.     

Ultraintense lasers: relativistic nonlinear optics and applications

Traditional optics and nonlinear optics are related to laser–matter interaction with eV characteristic energy. Recent progresses in ultrahigh intensity makes it possible to drive electrons with relativistic energy opening up the field of relativistic nonlinear optics. In the last decade, lasers have undergone orders-of-magnitude jumps in peak power, with the invention of the technique of chirped pulse amplification (CPA) and the refinements of femtosecond techniques. Modern CPA lasers can produce intensities greater than 10²¹ W/cm², one million times greater than previously possible. These ultraintense lasers give researchers a tool to produce unprecedented pressures (terabars), magnetic fields (gigagauss), temperatures (10¹⁰ K), and accelerations (10²⁵ g) with applications in fusion energy, nuclear physics (fast ignition), high-energy physics, astrophysics, and cosmology. They promote the optics field from the eV to the GeV.     

金属桥联双二茂铁配合物的结构与三阶非线性光学性质研究

三种金属桥联双二茂铁的三核配合物的合成、结构、电化学及三阶非线性光学性质,通过四圆X射线衍射测定,确定了铜配合物的晶体结构。铜配合物为高度畸变的平面四边形构型。双二茂铁处于顺式结构,这种结构由茂环间的π-π相互作用而变得稳定。研究表明,它们的结构、电化学性质及三阶非线性光学性质三者有密切的内在联系。平面型金属配合物桥联双二茂铁体系中电子离域程度高,在电化学上表现为两步连续单电子氧化过程,其三阶非线性光学效应较强,变形四面体型铜配合物桥联双二茂铁只有一个氧化还原过程,其三阶效应也较低。     

Interval-valued preference structures

Different languages that are offered to model vague preferences are reviewed and an interval-valued language is proposed to resolve a particular difficulty encountered with other languages. It is shown that interval-valued languages are well defined for De Morgan triples constructed by continuous triangular norms, conorms and a strong negation function. A new transitivity condition for vague preferences is suggested and its relationships to known transitivity conditions are established. A complete characterization of interval-valued preference structures is also provided.     

非正截曲率的完备Riemann流形在无穷远截曲率趋于零的条件

本文给出并证明了定理;设Ｍ为具非正截曲率的完备Ｒｉｅｍａｎｎ流形,Ｔ：［０,＋∞）→Ｍ为Ｍ上的正规测地线,Ｕ是沿Ｔ且初值为零的非平凡正常Ｊａｃｏｂｉ场,若存在ａ＞０,ｔ_０＞０,使得当ｔ≥ｔ_０时．