The ab initio quantum chemical calculation of MgH+ and Mg2H+

The potential energy curve of MgH+ and the potential energy surface of Mg₂H+ are calculated by quantum chemical ab initio SCF MO method with STO-3G basis set. The electronic wave functions and populations are obtained. The eqilibrium internuclear distance of MgH+ is 1.60 Å. There are two possible configurations of Mg₂H+: C and D . The former is (Mg-Mg-H)+, with bond length rM_g-M_g = 2.41Å and rM_g-H =1.63Å. The latter is (Mg-H-Mg)+, with bond length rM_g-H = 1.73Å. The cause of the stability of these species is discussed. The result of calculation about the bond length of MgH+ agrees reasonably well with experimental value. The conclusion about the stability of (Mg-Mg-H)+ ion supports the hypothesis proposed by Porter, based on thermodynamical calculation.     

从石英光纤废料中制备硅新工艺的实验研究

对石英光纤废弃物氢热还原过程进行了热力学分析,并利用X射线衍射分析法(XRD)、激光拉曼光谱(Laser Raman Spectroscopy)、X射线光电子能谱(XPS)及化学分析等对该新工艺进行了实验研究.产物中只检测到硅和氧两种元素且金属键硅质量含量在15%以上,说明该方法不仅可以实现该类危险废弃物的无害化处理,而且还可以作为高纯度太阳级硅的一个潜在的供给渠道,从而弥补太阳能电池硅光伏材料供应的不足.     

A relationship between the Berlekamp-Massey and the euclidean algorithms for linear feedback shift register synthesis

A relationship between the Berlekamp-Massey and the Euclidean algorithms for linear feedback shift register synthesis is established. In fact, by refining a sequence of polynomials appearing in the Euclidean algorithm, the sequence of characteristic polynomials computed by the Berlekamp-Massey algorithm will be achieved. A preliminary version of this paper was presented at the Oberwolfach Information Theory Meeting, May 12–16, 1986.     

Asymptotic behavior of solutions for a class of retarded difference equations

Consider the retarded difference equationx _n −x _n−1 =F(−f(x _n )+g(x _n−k )), wherek is a positive integer,F,f,g:R→R are continuous,F andf are increasing onR, anduF(u)>0 for allu≠0. We show that whenf(y)≥g(y) (resp. f(y)≤g(y)) fory∈R, every solution of (*) tends to either a constant or −∞ (resp. ∞) asn→∞. Furthermore, iff(y)≡g(y) fory∈R, then every solution of (*) tends to a constant asn→∞. Project supported by NNSF (19601016) of China and NSF (97-37-42) of Hunan     

The orbit method and the Virasoro extension of Diff(S): I. Orbital integrals

Using the finite dimensional example of , the universal covering of PSU(1,1), as a guide, we revisit the orbit method as it applies to , the universal central extension of . We clarify some aspects of the classification of coadjoint orbits, determine boundedness properties of the natural height function on these orbits, and calculate orbital integrals.     

关于电磁学教学的三点建议

本文就电磁学教学中常遇到的问题谈一点教学体会。