窄带光纤光栅的写入

改进相位掩模法写入光栅的装置,提高其机械稳定性和温度稳定性,不仅提高了光纤光栅的反射率,而且降低了带宽,特别是能在国产的光敏光纤上写出了大于99%反射率和小于02nm带宽的高质量的光纤光栅.这种光栅特别适用于光纤光栅传感方面的应用。     

利用超声测量水中含沙量垂线分布的方法

本文根据超声反射式测沙的原理，跟踪超声波在水中的传播，实时采集并获沙量沿垂线的分布规律，测量发射的一次超声脉冲，可得沙量分的瞬时特性；多次发射并取平均法。     

激光等离子体软X射线接近式光刻术初步研究

描述了用高功率脉冲激光打靶产生的等离子体作为软Ｘ射线源而进行的接近式软Ｘ射线光刻研究，采用负性辐射线光刻胶聚氯甲基苯乙烯，得到了一些新的实验结果。     

强激光在高Z等离子体中吸收的波长关系

利用“神光Ⅰ”输出的～５００Ｊ、１．０５μｍ，～２００Ｊ、０．５３μｍ激光和“星光Ⅱ”输出的～７０Ｊ、０．３５１μｍ激光，实验研究了激光与金圆盘靶作用产生的等离子体对激光的吸收，获得了激光１０°、４５°入射Ａｕ盘靶吸收的波长关系。实验结果与一维平面等离子体吸收模型计算的结果基本相符。     

Some Theorems for Hypersurface of Randers Spaces

In this paper, we consider the hypersurfaces of Randers space with constant flag curvature. (1) Let (Mⁿ⁺¹, F) be a Randers-Minkowski space. If (Mⁿ, F) is a hypersurface of (Mⁿ⁺¹, F) with constant flag curvature K=1, then we can prove that M is Riemannian. (2) Let (Mⁿ⁺¹, F) be a Randers space with constant flag curvature. Assume (M, F) is a compact hypersurface of (Mⁿ⁺¹, F) with constant mean curvature|H|. Then a pinching theorem is established, which generalizes the result of[Proc. Amer. Math. Soc., 120, 1223-1229 (1994)] from the Riemannian case to the Randers space.     

A novel cyclodimerization of 3-methyl-3-butenenitrile. An efficient synthesis of 4-cyanoisophorone

Dimerization of 3-methyl-3-butenenitrile (1) by lithium dialkylamide gave selectively 3,5,5-trimethyl-1-amino-4-cyanocyclohexa-1,3-diene (2), which was easily hydrolyzed by aqueous acid to afford 4-cyanoisophorone (3,5,5-trimethyl-4-cyano-cyclohex-2-enone) (3) quantitatively.     

Antisymmetrization effects on the effective internuclear potential

The effects of internuclear antisymmetrization in nucleus-nucleus scattering are studied by examining the structure of the exchange-Hamiltonian kernel function in the resonating group formulation. By investigating the features of the effective local potentials which are constructed to yield the same Born scattering amplitudes as the various nucleon-exchange terms in this kernel function, it is found that, among all exchange terms, the one-exchange and core-exchange terms have the largest influence. In addition, this investigation shows that the one-exchange terms, giving rise to a Wigner-type effective potential, are generally important in all scattering systems and over a wide energy range, while the core-exchange terms, giving rise to a Majorana-type effective potential, are generally important only when the nucleon-number difference of the interacting nuclei is rather small. Based on these results, it can therefore be concluded that, if a local-potential model is adopted to analyze experimental scattering results, then the real central part of the effective potential in this model must, in general, contain a Majorana exchange component or an odd-even l-dependence. Explicit resonating-group calculations in ${}^3\text{He}\text{+ α}\text{and}\text{α +}{}^{16}\text{O}$ systems, where contributions from individual exchange terms are studied, have also been performed. From this study, one finds that the conclusions mentioned above, reached in the Born approximation, may in fact be valid even in the lower-energy region.     

卤磷酸钙荧光粉中锑酸钙的检测及其形成原因探讨

众所周知,在卤磷酸钙荧光粉(以下简称卤粉)烧制过程中常形成锑酸钙(CaSb2O6:Mn)、正磷酸钙(Ca3(PO4)2:Sb,Mn)、焦磷酸钙(Ca2P2O7:Sb,Mn)等杂质相.已有不少工作研究了这些杂质相对卤粉效率的影响.这些研究表明,上述杂质相的存在降低了卤粉的发光效率,从而用含有杂质相的卤粉制灯,使灯的光通降低和光衰增大.曾有人使用化学分析方法来检测卤粉中的锑酸钙,即通过分析测定卤粉中Sb5+的含量来对应计算出锑酸钙的含量.最近,А.Е.Скреблюков等人提出了通过改变激发光波长测量卤粉的发光光谱来检测锑酸钙的方法,这一方法的特点是简便、可靠、准确、快速.本工作应用这一方法对几种卤粉中的锑酸钙进行了检测,并就卤粉制备过程中锑酸钙生成的原因进行了初步探讨.     

The block decomposition of a vandermonde matrix and its applications

This paper presents a new algorithm for the solution of linear equations with a Vandermonde coefficient matrix. The algorithm can also be used to solve the dual problem. Since the algorithm uses a block decomposition of the matrix, it is especially suitable for parallel computation. A variation of the block decomposition leads to the efficient solution of the interpolation problem with complex-conjugate interpolation points where the coefficients of the interpolating polynomial are real. In addition the algorithm can be used to solve some kinds of confluent Vandermonde systems.W. P. Tang is a graduate student in the Computer Science Department at Stanford University, on leave from the Institute of Computing Technology of the Chinese Academy of Science in Peking.The work of Professor Golub was in part supported by NSF Grant No. MCS78-11985.