Ring-opening polymerization of cyclobutane adduct of dimethyl 1,1-dicyanoethylene-2,2-dicarboxylate and ethyl vinyl ether

For an extension of the work on the ring-opening polymerizations of cyclobutane adducts of strong donor olefins and strong acceptor olefins yielding novel alternating copolymers of those olefins, the ring-opening polymerization of the cyclobutane adduct 3 of dimethyl 1,1-dicyanoethylene-2,2-dicarboxylate (DDED) and ethyl vinyl ether (EVE) is investigated. Cyclobutane 3 reacted with methanol and acetic acid at ambient temperature to yield the corresponding ring-opened adducts. The polymerizations of 3 were carried out with anionic initiators, tertiary amines, ammonium halides, and Lewis acids, respectively, according to the polymerization methods of the cyclobutane adduct 1 of tetracyanoethylene (TCNE) and EVE. All these polymerization catalysts except for ammonium halides were effective for the polymerization of 3 , yielding alternating copolymers of DDED and EVE. The chain transfer reactions of the polymerization with anionic initiators are also discussed on the basis of a model reaction. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1563–1570, 1997     

Cavity ring‐down study of BrO radicals: Kinetics of the Br + O3 reaction and rate of relaxation of vibrationally excited BrO by collisions with N2 and O2

Cavity ring‐down (CRD) techniques were used to study the kinetics of the reaction of Br atoms with ozone in 1–205 Torr of either N₂ or O₂, diluent at 298 K. By monitoring the rate of formation of BrO radicals, a value of k(Br + O₃) = (1.2 ± 0.1) × 10⁻¹² cm³ molecule⁻¹ s⁻¹ was established that was independent of the nature and pressure of diluent gas. The rate of relaxation of vibrationally excited BrO radicals by collisions with N₂ and O₂ was measured; k(BrO(v) + O₂ → BrO(v − 1) + O₂) = (5.7 ± 0.3) × 10⁻¹³ and k(BrO(v) + N₂ → BrO(v − 1) + N₂) = (1.5 ± 0.2) × 10⁻¹³ cm³ molecule⁻¹ s⁻¹. The increased efficiency of O₂ compared with N₂ as a relaxing agent for vibrationally excited BrO radicals is ascribed to the formation of a transient BrO–O₂ complex. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 125–130, 2000     

Specht's ratio and complementary inequalities to Golden–Thompson type inequalities on the Hadamard product

As a converse of the arithmetic–geometric mean inequality, W. Specht [Math. Z. 74 (1960) 91–98] estimated the ratio of the arithmetic mean to the geometric one. In this paper, we shall show complementary inequalities to the matricial generalization of Oppenheim's inequality and the Golden–Thompson type inequalities on the Hadamard product by T. Ando [Linear Algebra Appl. 26 (1979) 203; Linear Algebra Appl. 241–243 (1996) 105], in which Specht's ratio plays an important role. As an application, we shall obtain a complementary inequality to the Hadamard determinant inequality.     

快速气相色谱法分析石油饱和烃

提出了一种快速分析原油和岩石抽提物中饱和烃组分的毛细管气相色谱(GC)方法。由于在该方法中采用了细内径毛细管柱,故饱和烃的GC分析周期由原来的80~90 min缩短至15 min,分析速度加快约5倍,大大提高了工作效率和仪器通量,使石油饱和烃得到了很好的分离分析。该方法符合中华人民共和国石油天然气行业标准SY/T5120-1997的要求。20万理论塔板数的细径柱的应用,可供石油中异构烷烃,尤其是甾烷、萜烷类的气相色谱/质谱(GC/MS)快速分析方法及芳烃的GC快速分析方法借鉴。     

Higher dimensional extensions of substitutions and their dual maps

Given a substitution σ ond letters, we define itsk-dimensional extension,E _k (σ), for 0≤k≤d. Thek-dimensional extension acts on the set ofk-dimensional faces of unit cubes inR ^d with integer vertices. The extensions of a substitution satisfy a commutation relation with the natural boundary operator: the boundary of the image is the image of the boundary. We say that a substitution is unimodular (resp. hyperbolic) if the matrix associated to the substitution by abelianization is unimodular (resp. hyperbolic). In the case where the substitution is unimodular, we also define dual substitutions which satisfy a similar coboundary condition. We use these constructions to build self-similar sets on the expanding and contracting space for an hyperbolic substitution.     

Preparation of poly(2,4-dichloro-6-vinyl-1,3,5-triazine-co-styrene)s as polymer supports containing two replaceable groups in monomer unit

Poly(2,4-dichloro-6-vinyl-1,3,5-triazine-co-styrene)s were prepared by the reaction of poly(2,4-diamino-6-vinyl-1,3,5-triazine-co-styrene)s with hydrochloric acid, and followed by treatment with thionyl chloride and N,N-dimethylformamide. The chlorine atoms in the resulted polymers were replaced readily by several nucleophiles such as amide, alkoxide, and mercaptide to afford the corresponding polymers in moderate yields. Among these, polymers containing oligo (oxyethylene) groups at both 2 and 4 positions of 1,3,5-triazine ring worked effectively as phase transfer catalysts for the reaction of n-octyl bromide with alkali metal thiocyanates in toluene–water systems. However, polystyrenes containing only one oligo (oxyethylene) group in monomer unit scarcely exhibited the activity under these conditions although the degree of loading of the functional group was almost the same. The activity depended on the number of oxyethylene units, and the selectivity to alkali metal ions was also observed. © 1992 John Wiley & Sons, Inc.     

Elucidation of Chemical Interactions between Crude Drugs Using Quantitative Thin-Layer Chromatography Analysis

To elucidate the interactions between crude drugs in Kampo medicines (traditional Japanese medicines), it is important to determine the content of the constituents in a cost-effective and simple manner. In this study, we quantified the constituents in crude drug extracts using thin-layer chromatography (TLC), an inexpensive and simple analytical method, to elucidate the chemical interactions between crude drugs. We focused on five crude drugs, for which quantitative high-performance liquid chromatography (HPLC) methods are stipulated in the Japanese Pharmacopoeia XVIII (JP XVIII) and compared the analytical data of HPLC and TLC, confirming that the TLC results corresponded with the HPLC data and satisfied the criteria of JP XVIII. (Z)-ligustilide, a major constituent in Japanese Angelica Root, for which a method of quantification has not been stipulated in JP XVIII, was also quantitatively analyzed using HPLC and TLC. Furthermore, Japanese Angelica Root was combined with 26 crude drugs to observe the variation in the (Z)-ligustilide content from each combination by TLC. The results revealed that combinations with Phellodendron Bark, Citrus Unshiu Peel, Scutellaria Root, Coptis Rhizome, Gardenia Fruit, and Peony Root increased the (Z)-ligustilide content. Quantifying the constituents in crude drug extracts using the inexpensive and simple TLC method can contribute to elucidating interactions between crude drugs in Kampo medicines, as proposed by the herbal-pair theory.     

Transition-Metal-Free Synthesis of Unsymmetrical Diaryl Tellurides via SH2 Reaction of Aryl Radicals on Tellurium

Although diaryl tellurides are parent organotellurium compounds, their synthesis methods, especially for unsymmetrical ones, are limited. This may be due to the instability of diaryl tellurides and their synthesis intermediates under reaction conditions. Radical reactions are known to exhibit excellent functional group selectivity; therefore, we focused on a bimolecular homolytic substitution (S_H2) reaction between the aryl radical and diaryl ditelluride. Aryl radicals are generated from arylhydrazines in air and captured by diaryl ditellurides, resulting in a selective formation of unsymmetrical diaryl tellurides with high yields. The electronic effects of the substituents on both arylhydrazines and diaryl ditellurides on the S_H2 reaction of tellurium are also discussed in detail.     

Application of High-Sensitivity UV photoemission Spectroscopy to Examine the Electronic Structure of Thermophilic Rhodopsin

Abstract

The electronic structures of materials such as HOMO and LUMO are essential information to understand their functions. Photoemission spectroscopy, which is the most standard technique to examine the electronic structures of various materials, has been not well applied to biomolecules mostly due to sample charging and poor sensitivity. Very recently, we have developed high-sensitivity photoemission spectroscopy (HS-PES) using low photon energy. In this study, HS-PES has been successfully applied to a thermophilic rhodopsin (TR) film. The high sensitivity of our technique enabled to observe the HOMO region of retinal part in TR without any problem due to sample charging. This technique is expected to explore the electronic structures of various proteins.     

Free Self-decomposability and Unimodality of the Fuss–Catalan Distributions

Journal of Statistical Physics - We study properties of the Fuss–Catalan distributions $$\mu (p,r)$$, $$p\ge 1$$, $$01$$ there exists $$r_{0}(p)$$, with $$p-1