垮越临界温度的分子筛吸附: 微孔体积填充理论的适用性

用高真空重量法测定了NaX分子筛对不同吸附质NH3, H2O, C2H5OH等的吸附等温线, 用微孔体积填充理论对吸附等温线进行非线性拟合, 得到满意结果。表明该理论不但可扩展到以静电场为主的吸附体系, 还可适用于吸附温度高于吸附质临界温度的吸附体系。计算结果表明, NaX吸附不同吸附质测得的极限空腔体积基本相同, 且与结构分析得到的空腔体积一致, 进一步表明微孔体积填充理论对该体系的适用性。计算了各种吸附质的极限吸附量, 以及某填充度下的蚊分吸附热随着温度的变化趋势。可为固体吸附式制冷系统的设计与制造提供理论依据及有关掺数。     

二维网状结构超分子化合物[Cu(dafo)2(H2O)2](Cl04)2的两种同分异构体的合成与表征

用4，5—二氮芴-9-酮（dafo）、邻苯二甲酸、高氯酸铜和4，5—二氯芴—9— 酮(dafo)、苯甲酸、高氯酸铜进行混和反应时分别得到亮蓝色和蓝绿色晶体，它们 的结构通过单晶X射线衍射法测定。其单晶结构表明，这两种化合物是同分异构体 ，组成都是C22H16Cl2CuN4O12。这两种化合物是通过氢键形成的具有二维网状结构 的超分子化合物，并通过元素分析、红外光谱、热分析对两种化合物进行了表征。     

Some Extremal Properties of Section Spaces of Banach Bundles and Their Duals,II

Let π : E → X be a real Banach bundle with section space Γ(π), where X is a compact Hausdorff space. We complete the characterization of weak-* and sequential weak-* points of continuity in the unit ball of Γ(π) ? for certain classes of bundles (which include the trivial ones), which was begun in an earlier paper. The proofs avoid the use of vector measures.     

Killing Pairs in Flat Space

In this paper the integrability conditions for Killing pairs in flat spaces are investigated and it is shown that only trivial Killing pairs exist.     

Activation and Facile Dealkylation of Monooxides of 1,8-Bis(alkylthio)naphthalene and 2,2′-Bis(alkylthio)biphenyl with Triflic Anhydride via Dithiadications

Abstract

Dithiadications bearing 1,8-bis(alkylthio)naphthalene 2A(a-e) and 2,2′-bis(alkylthio)biphenyl 2B(a-e) structure undergo either the facile deprotonation from the methyl group or dealkylation from the methylene groups by the triflate anion. Dications 2A(a) and 2B(a) having methyl groups were deprotonated readily to afford cyclic sulfonium salts 3A(a) and 3B(a). However, dithiadications 2A(b-e) and 2B(b-e) having ethyl, propyl, isopropyl and benzyl groups were readily dealkylated even at -45°C to give thiasulfonium salts 4A(b-e) and 4B(b-e) and alkyl triflates 5(a-e) in good yields. The intermediary formation of dithiadications 2A(a-e) and 2B(a-e) were confirmed by direct observation using NMR spectroscopy, D-labelled experiments and trapping experiments.     

Letter: A Potential for the Lanczos Spintensor in Kerr Geometry

We show a generator of the Lanczos spintensorfor a rotating black hole.     

On the Geometry of Generalized Robertson-Walker Spacetimes: Geodesics

The geometry and, especially, the geodesics of a class of spacetimes generalizing Robertson-Walker ones (without any assumption on the fiber) is studied, under a global point of view. Our study covers geodesic connectedness, geodesic completeness and stability of completeness.     

Gravity as a Source of Phase Transitions

After going through several distinguished examples, we argue that gravity is definitely a source of phase transitions of quite different nature: usual scalar effective potential ones, chiral symmetry transitions and even transitions involving the chromomagnetic vacuum. In such context, we emphasize the fact that curvature-induced phase transitions of those kinds—where an interplay between general relativity and elementary particle physics occurs—can be used in the construction of new models of the inflationary universe.     

Effect of Geometry,Loading and Elastic Moduli on Critical Parameters in a Nanoindentation Test in Polymeric Matrix Composites with a Nonhomogeneous Interphase

Fiber nanoindentation models are developed for polymeric matrix composites with nonhomogeneous interphases. Using design of experiments, the effects of geometry, loading and material parameters on the critical parameters of the indentation test such as the load–displacement curve, the maximum interfacial shear and normal stresses are studied. The sensitivity analysis shows that the initial load–displacement curve is dependent only on the indenter type, and not on parameters such as fiber volume fraction, interphase type, thickness of interphase, and boundary conditions. The interfacial tensile radial stresses are not sensitive to indenter type, or to type and thickness of interphase, while the interfacial compressive radial stresses are sensitive mainly to boundary conditions and thickness of interphase; however, the influence of these factors on the interfacial radial stresses can be large. In contrast, the interfacial shear stress is sensitive to all factors, but the influence of the factors is relatively small.     

Enhancement of adhesion between copper and vinyl ester in glass fiber–vinyl ester composites

The paper describes surface treatment methods to improve adhesion between copper and vinyl ester in glass fiber–vinyl ester composites. Surface treatment methods were developed for commercially available copper that was optimized for epoxies and adhesion performance was compared based on 90° peel strength measurements. Four surface treatments for copper were tested: (i) co-cured Epon/vinyl ester; (ii) fully cured Epon; (iii) epoxy film adhesive; and (iv) γ-MPS silane along with two baseline systems: copper/vinyl ester and copper/epoxy. Measured average peel strengths for the surface treatments were 21%, 101%, 110% and 91% of the baseline copper/vinyl ester system, respectively. Compared to the copper/epoxy system, fully cured Epon, epoxy film adhesive and the silane treatment generated comparable adhesion between copper and vinyl ester. For all samples tested, mixed cohesive/adhesive failure modes were observed. Overall, the surface treatment with the silane coupling agent is the most appropriate method for obtaining comparable and uniform performance compared to copper/glass fiber/epoxy system (FR4 materials).