A new type of two-dimensional packed + capillary column GC system. I. Theory

Summary To match the need of high efficiency capillary column (plate number N₂, Plate height H₂ and carrier gas linear velocity U₂), a new high efficiency packed column (N₁, H₁ and U₁) at high carrier gas velocity with small capacity factor has been developed in the light of theoretical discussion of factors effecting the column efficiency utilization ratio.     

Polyamide Layer Chromatography. VIII. Preparation of Polyamide Layer on Poly(ethylene terephthalate) Film and its Application to Aromatic Nitro Compounds

Poly(ethylene terephthalate) film was used as supporter for preparation of polyamide layer. The most convenient method of preparation was described. This layer can be cut into any size and its sensitivity is higher than the glass plate supported layer. Twenty aromatic nitro compounds were used to show the behavior of polyester film based polyamide layer.     

数均聚合度计算的教学方法

总结毛者提出的线型缩聚中当量系数的新定义及引入缩聚体系单体平均官能度的新方法，本文总结出了一套讲授数均聚合度计算问题的简单方法。     

On the second eigenfunctions of the Laplacian in R2

A conjecture about the nodal line of a second eigenfunction states that the nodal line of a second eigenfunction divides the domain by intersecting with the boundary of transversely, where is a bounded convex domain ofR ². We prove this conjecture provided has a symmetry. Also, we prove the multiplicity of the second eigenvalue is two at most provided is a bounded convex domain ofR ².Supported in part by NSF DMS 84-09447Home Institution: Department of Mathematics, University of California, San Diego, La Jolla, CA 92093, USA     

Characterization of the Phosphoryl-Nitrogen Linkages in Histone H4

In earlier work we nave described and partially characterized two histone kinases from regenerating rat liver and other tissues which catalyze the transfer of the γ-phosphoryl group from ATP to histones. The histone phosphates thus formed were observed to be acid-labile and base-stable. In the present study we report on the specificity of one of these enzymes, namely, the kinase which is optimally active at pH 9. This enzyme appears to be relatively specific for the two histidine residues of histone H4. These histidines occur at positions 18 and 75, and both are phosphorylated. However, when regenerating rat liver was the source of enzyme, the product was 1-phosphohistidine, whereas the enzyme from Walker-256 carcinosarcoma catalyzed the formation of 3-phosphohistidine.     

Chemistry of O-Benzoquinones and Masked O-Benzoquinones I. Diels-Alder Reactions of O-Benzoquinones with Dimethyl Acetylenedicarboxylate and Phenylacetylene

Diels-Alder reactions of six o-benzoquinones with dimethyl acetylenedicarboxylate has been examined. The yields of adducts vary with the natures of the o-benzoquinones, 3,4-Di-n-propyl-(1c), 3,6-di-n-propyl (1d). 3. 4-diallyl-(1e) and 3, 6-diallyl-o-benzoquinone (1f) are found to give bicyclic a-diketones exclusively without the formation of 1,4-dioxine derivatives, the yields ranging from 20 to 70%. In the case of 4, 5-dimethoxy-o-benzoquinone, dimethyl 4, 5-dimethoxyphthalate is produced in 42% yield, presumably derived from the decomposition of the corresponding initially formed α-diketone. 3, 6-Di-n-propyl-4, 5-dimethoxy-o-benzoquinone deteriorates without addition to dimethyl acetylenedicarboxylate upon heating. The additions of o-benzoquinones 1c , 1d and 1f to phenylacetylene are also studied. The yields of adducts, α-diketones, range from 23% to 82%.     

Thermal analysis of composites based on crystalline polymers and metals

Differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and infrared (IR) spectroscopy have been used to examine the chemical and physical changes (crystallinity, accumulation of oxygen-containing groups, etc.) during thermal oxidation of polyethylene, polypropylene and Penton contained in coatings and metalfilled films, taking into account the thickness of the polymer layer and catalytic activity of the metal.

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Zusammenfassung DSC, thermogravimetrische Analyse (TG) und infrarot (IR) Spektroskopie wurden zur Untersuchung der während der thermischen Oxidation von in Belägen und metallgefüllten Filmen enthaltenem Polyäthylen, Polypropylen und Penton stattfindenden chemischen und physikalischen Veränderungen (Kristallinität, Anhäufung stickstoffhaltiger Gruppen usw.) eingesetzt. Hierbei wurden die Stärke der Polymerschicht und die katalytische Aktivität des Metalls in Betracht genommen.

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Mechanical and electrochemical effects on surface convection and on emulsification new criteria

Theoretical and experimental studies of surface instability for charged and polarized interfaces between two immiscible liquids are reviewed. A linear analysis of stability shows the role of mechanical and electrochemical para meters for the onset of interfacial convection. Three cases are studied: 1) For the restored Boltzman distribution in bulk phases, the stability is only governed by the interfacial tension through the composition between mechano-chemicaland electrical contributions to the surface free energy; 2) for the non-restored Boltzman distribution, the stability is also governed by the discontinuity of mechanical quantities (density-viscosity) associated with the discontinuity of electrochemical and electrical quantities (dielectric constant-solute concentration-diffusion coefficient, potential drop); and 3) for concentrated charged and dipolar monolayers, the convection criteria of stability are directly related to the discontinuity of mechanical quantities (density-viscosity) associated with the discontinuity of electrochemical quantities (dielectric constant).Additional experiments on emilsification and demulsification were performed in order to verify this last theoretical prediction.