Classification of oxide glasses: A polarizability approach

A classification of binary oxide glasses has been proposed taking into account the values obtained on their refractive index-based oxide ion polarizability α_O2−(n₀), optical basicity Λ(n₀), metallization criterion M(n₀), interaction parameter A(n₀), and ion's effective charges as well as O1s and metal binding energies determined by XPS. Four groups of oxide glasses have been established: glasses formed by two glass-forming acidic oxides; glasses formed by glass-forming acidic oxide and modifier's basic oxide; glasses formed by glass-forming acidic and conditional glass-forming basic oxide; glasses formed by two basic oxides. The role of electronic ion polarizability in chemical bonding of oxide glasses has been also estimated. Good agreement has been found with the previous results concerning classification of simple oxides. The results obtained probably provide good basis for prediction of type of bonding in oxide glasses on the basis of refractive index as well as for prediction of new nonlinear optical materials.     

CO吸附在过渡金属铂表面的微观动力学研究

建立了处理双原子分子-表面相互作用的推广的LEPS势.借助推广的LEPS势,系统研究了一氧化碳分子在铂低指数表面吸附的动力学特性,重现了低指数表面的分子吸附热、吸附几何及本征振动等实验数据；鉴定了某些不合理的文献信息,预测了实验尚未探测到的重要信息:预测到Pt(100)表面四重洞位的C－O伸缩振动频率为1 962.60 cm－1;预测到Pt(110)表面吸附态的C－O及C－Pt键长分别为115.1、147 pm.     

Kubische Berechnung der Retentionsindices ohne Kenntnis der Totzeit tm

Zusammenfassung In der vorliegenden Arbeit wird eine Methode zur Retentionsindex-Bestimmung beschrieben, die von einem kubischen Zusammenhang zwischen Bruttoretentionszeit-Differenzen der Referenzhomologen und der Kohlenstoffzahl ausgeht. Hieraus ergeben sich direkt die Nettoretentionszeiten. Der Fehler der Totzeitbestimmung entfällt bei dieser Methode. Mit den so gewonnenen Nettoretentionszeiten erhält man über einen kubischen Zusammenhang zwischen 1g t_s=f(C) die Retentionsindices. Extrapolationen und Interpolationen sind über 300 Retentionsindexeinheiten mit einem mittleren Fehler von ±0,02 Retentionsindexeinheiten möglich. Das Verfahren bietet sich für eine automatische Berechnung der I-Werte mittels on-line-Datenverarbeitung an.

---

Cubic calculation of retention indices without determining the dead-time t_m

Summary The method for the calculation of retention indices described here is based on a third order relationship between the logarithm of differences of unadjusted retention times of homologues and the carbon number. From this adjusted retention times are directly calculated. A determination of the dead-time is not necessary thus avoiding the errors connected with this factor. A cubic equation for the logarithm of the adjusted retention time lg t_s as a function of carbon number C_n is used for the retention index calculation. Extrapolations and interpolations can be done over a range of 300 index units with an average deviation of ±0.02 i.u.. The method offers the possibility of an automated on-line calculation of retention indices by computer merely on the basis of unadjusted retention times.

     

Capillary gas chromatography of C1−C4 alkyl tert-butyl ethers

Summary The separation of C₁–C₄ alkyl tert-butyl ethers with the general formula (CH₃)₃C–O–R (R-alkyl substituent) on fused-silica capillary columns coated with dimethylsilicone and cyanopropylmethylsilicone stationary phases was investigated. Retention indices were determined at two temperatures in order to understand their chromatographic behaviour. The respective standard deviations were 0.3 and 0.5 i.u.     

Morse Index of Multiple Blow-up Solutions to the Two-Dimensional Sinh-Poisson Equation

In this paper we consider the Dirichlet problemwhere $\rho$ is a small parameter and $\Omega$ is a $C^2$ bounded domain in $\mathbb{R}^2$. In [1], the author proves the existence of a $m$-point blow-up solution $u_\rho$ jointly with its asymptotic behaviour. We compute the Morse index of $u_\rho$ in terms of the Morse index of the associated Hamilton function of this problem. In addition, we give an asymptotic estimate for the first $4m$ eigenvalues and eigenfunctions.     

Real-time onboard wind and windshear determination,part 2: Detection

This paper is concerned with windshear detection in connection with real-time wind identification (Ref. 1). It presents a comparative evaluation of two techniques, one based on the shear/downdraft factor and one based on the wind difference index. The comparison is done with reference to a particular microburst, that which caused the 1985 crash of Flight Delta 191 at Dallas-Fort Worth International Airport.The shear/downdraft factor has the merit of combining the effects of the shear and the downdraft into a single entity. However, its effectiveness is hampered by the fact that, in a real situation, the windshear is accompanied by free-stream turbulence, which tends to blur the resulting signal. In turn, this results in undesirable nuisance warnings if the magnitude of the shear factor due to free-stream turbulence is temporarily larger than that due to true windshear. Therefore, proper filtering is necessary prior to using the shear/downdraft factor in detection and guidance. One effective way for achieving this goal is to average the shear/downdraft factor over a specified time interval . The effect of on the average shear/downdraft factor is studied.     

Preparation and characterization of a viscosity index improver for naphthenic and paraffinic base oils

Copolymers of -methyl styrene and 2-ethylhexyl acrylate were prepared in a benzene solution. The presence of the copolymers were confirmed by solubility, IR and NMR tests. The molecular weight and the polydispersity of the polymers were estimated by GPC. The copolymers obtained were blended with paraffinic and naphthenic base oils. The viscosity, the viscosity index (VI) the Q value as well as the stability to shear and oxidation were obtained for these blends. The results are compared with the results obtained with an oil blend containing a commonly used high temperature additive. Two of the copolymers obtained have shown to be good alternatives for specific applications.Presented at the Symposium, 76^th CSC Congress, Sherbrooke, Quebec, May 30–June 3, 1993, honoring Professor Donald Patterson on the occasion of his 65^th birthday.     

CHAOS FOR MIXING TRANSFORMATIONS

ＣＨＡＯＳＦＯＲＭＩＸＩＮＧＴＲＡＮＳＦＯＲＭＡＴＩＯＮＳ￥ＬＩＡＯＧＯＮＧＦＵ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ,ＪｉｌｉｎＵｎｉｖｅｒｓｉｔｙ,Ｃｈａｎｇｃｈｕｎ１３００２３,Ｃｈｉｎａ．）Ａｂｓｔｒａｃｔ：Ｆｏｒａｃｌａｓｓｏｆｍ...     

Complete solutions of a family of quartic Thue and index form equations

Continuing the recent work of the second author, we prove that the diophantine equation

for has exactly 12 solutions except when , when it has 16 solutions. If denotes one of the zeros of , then for we also find all with .

     

Geometric indices and the Alexander polynomial of a knot

It is well-known that any Laurent polynomial satisfying and is the Alexander polynomial of a knot in . We show that can be realized by a knot which has the following properties simultaneously: (i) tunnel number 1; (ii) bridge index 3; and (iii) unknotting number 1.