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31.
Abe K Abt I Ahn CJ Akagi T Allen NJ Ash WW Aston D Baird KG Baltay C Band HR Barakat MB Baranko G Bardon O Barklow T Bazarko AO Ben-David R Benvenuti AC Bienz T Bilei GM Bisello D Blaylock G Bogart JR Bolton T Bower GR Brau JE Breidenbach M Bugg WM Burke D Burnett TH Burrows PN Busza W Calcaterra A Caldwell DO Calloway D Camanzi B Carpinelli M Cassell R Castaldi R Castro A Cavalli-Sforza M Church E Cohn HO Coller JA Cook V Cotton R Cowan RF Coyne DG D'Oliveira A Damerell CJ Daoudi M 《Physical review D: Particles and fields》1995,52(7):4240-4244
32.
We investigate the Ward identities of theW
symmetry in the super-Liouville theory coupled to the super-conformal matter of central charge
. The theory is classified into two chiralities. For the positive chirality, all gravitationally dressed scaling operators are generated from theq–1 gravitational primaries by one of the ring generators in the R-sector acting on them repeatedly. After fixing the normalizations of the dressed scaling operators, we find that the Ward identities are expressed in the form of theusual
W
q
algebra constraints as in the bosonic case:W
n
(k+1)
,=0, (k=1,...,q–1;nZ1–k), where the equations for even and oddn come from the currents in the NS- and the R-sector respectively. The non-linear terms come from the anomalous contributions at the boundaries of moduli space. The negative chirality is defined by interchanging the roles ofp andq. Then we get theW
p
algebra constraints. 相似文献
33.
Takeshi Wada Hiroshi Sekiya Sueo Machi 《Journal of polymer science. Part A, Polymer chemistry》1975,13(10):2375-2389
The effects of temperature, dose rate, and monomer concentration on the heterogeneous polymerization of acrylamide in acetone–water mixtures have been studied. Heterogeneous polymerization takes place in mixtures containing less than 60 vol-% water. The polymerization is steady in acetone and nonsteady in acetone an nonsteady in mixtures containing 10–50 vol-% water. The average rate of polymerization is highest in mixtures with about 20 vol-% water. Polymer molecular weight increases with the increasing water content in range 0–10 vol-% and does not change in the range of 30–70 vol-% water. For the polymerization in acetone and an acetone–water 60/40 mixture the activation energies are 2.3 and ?1.8 kcal/mole, the dose rate exponents of rate are 0.78 and 0.52, and the monomer concentration exponents of rate are 0.5 and 1.6, respectively. The polymer molecular weight increases with decreasing dose rate, decreasing temperature, and increasing monomer concentration. These results are discussed in connection with the mechanism of heterogeneous polymerization and the solvent effect. 相似文献
34.
Oxidative cleavage reactions of catechol with CuCI to give monoester of cis,cis-muconic acid in pyridine containing alcohol was investigated under various conditions. The same oxidation was carried out also with the systems of KO2/CuCl2 and KOH/CuCl2 in pyridine containing alcohol in the absence of oxygen. Phenol was oxidized with the same oxidizing systems to give the same monoester of muconic acid. 相似文献
35.
Yoshio Imai Hiroshi Koga 《Journal of polymer science. Part A, Polymer chemistry》1973,11(10):2623-2632
New thermally stable poly(imide-oxoisoindolobenzothiadiazine dioxides) (PIOD) have been prepared by the three-step cyclopolycondensation reaction of diaminobenzenesulfonamides with aromatic tetracarboxylic dianhydrides. The polymerization proceeded through the formation of poly(amic acid-sulfonamides) (PAAS), followed by cyclodehydration to yield polyimide-sulfonamides (PIS), which were subsequently converted to PIOD at 300°C. PAAS having inherent viscosities in the range of 0.1–0.5 in N-methyl-2-pyrrolidone (NMP) were obtained in approximately quantitative yield. PIOD were insoluble in most organic solvents, whereas PAAS and PIS were soluble in NMP and dimethyl sulfoxide. Differential thermal analysis and thermogravimetric analysis indicated that PIOD began to decompose at 460°C in air. The cyclodehydration of the model compounds was also investigated. 相似文献
36.
Hiroshi Sakurai Akira Tatematsu Hisao Nakata 《Journal of mass spectrometry : JMS》1973,7(9):1109-1110
A novel rearrangement reaction for a methyl group is found in doubly charged ion mass spectra of p-substituted acetophenone derivatives. The driving force for the reaction is discussed. 相似文献
37.
Mikio Hori Tadashi Kataoka Hiroshi Shimizu Eiji Imai Yukiharu Matsumoto Iwao Miura 《Tetrahedron letters》1981,22(13):1259-1262
The novel ring transformation reactions were found in the reactions of 1,3,7,9-tetra-alkyl-8,9-dihydroxanthines and acetylenic compounds. The reaction of the dihydroxanthine with DMAD gave a propellane type compound and with methyl propiolate afforded the similar type compound and a pyrimido[4,5-b]diazepine derivative. The mechanism of these reactions was also discussed. 相似文献
38.
Gas-phase ionization potentials of tetraphenylporphine and some metallotetraphenylporphines have been determined by the method of photocurrent measurements in nonpolar solvents reported previously [1]. The values obtained range from 5.9 to 6.3 eV, depending on the central metal ion, correlating well with the reported polarographic oxidation potentials. It has been concluded that photoelectron ejection from these complexes in isooctane occurs from the porphyrin π-system in all cases including Co(II) tetraphenylporphine, in which the electron is thought to be removed from the metal in polar solvents. 相似文献
39.
Kaoru Iwata Tsuneo Hagiwara Hiroshi Matsuzawa 《Journal of polymer science. Part A, Polymer chemistry》1986,24(5):1043-1051
The reciprocity effect under intense illumination was studied with photocrosslinkable polyesters of p-phenylenebis(α-cyanobutadiene carboxylic acid) (I), m-phenylenebis(α-cyanobutadiene carboxylic acid) (II), and p-phenylenebis(acrylic acid) (III), with an argon ion laser as a light source. The reciprocal sensitivities of I, II, and III were 5.0, 1800, and > 105 mJ/cm2, respectively. II and III required sensitization to enhance their sensitivities to a level at which reciprocity effects could be measured. I obeyed the reciprocity law over a wide range of exposure times from seconds to microseconds. Both II′, a copolyester of II, and III showed a dramatic decrease of sensitivity in high-intensity/short-time exposure when sensitized by 9,10-phenanthraquinone and pyrylium salts. 相似文献
40.
Summary The “chemical” relaxation of stress either in Amilan (6-Nylon) or polyvinyl alcohol caused by penetration of water vapor was
studied at 40% R. H. and temperatures 15, 30, and 50° C. A theory was presented of the chemical relaxation in a polymer which
comprises penetrant-sensitive bonds as the crosslinkages between the molecular chains. This theory assumes the diffusion coefficient
of penetrant in the polymer to he independent of concentration and any other factors. It was found that the system Amilan-water
behaves in exact conformity with the theory over the ranges of elongation and temperature studied. The diffusion coefficient,D, of water in Amilan could thus be evaluated from the chemical relaxation data, using the theory presented, as functions of
elongation and temperature. An ordinary sorption experiment was carried out for this system at 40% R. H. and 16.8° C and demonstrated
that the diffusion of water in Amilan was Fickian with a constant diffusion coefficient. Both diffusion coefficients from
the chemical relaxation data and the sorption. data were found to agree quite well when the former was extrapolated to zero-strain.
The chemical relaxation behavior in the system polyvinyl alcohol-water was markedly different from that expected from the
theory, suggesting primarily that the diffusion coefficient of water in this polymer was not constant. A parallel evidence
for this fact was obtained from sorption measurements on this system, which demonstrated the diffusion in this system to be
dependent both on concentration and time.
From these results it may be concluded that the chemical relaxation technique, when combined properly with an adequate theory,
can be used not only to evaluate the diffusion coefficient of penetrant in a given polymer solid but also to investigate,
at least qualitatively, the type of sorption behavior characteristic of the system under given experimental conditions.
Zusammenfassung Die chemische Spannungsrelaxation in Amilan (6-Nylon) und Polyvinylalkohol, verursacht durch Eindringen von Wasserdampf, wurde bei 40% r. F. und Temperaturen von 15, 30 und 50° C untersucht. Es wird eine Theorie der chemischen Relaxation von Polymeren vorgelegt, die als empfindliche Bindungen auf das eindringende Niedermolekulare die Vernetzungen zwischen den molekularen Ketten betrachtet. Diese Theorie setzt voraus, da? der Diffusionskoeffizient im Polymeren für die eindringende Substanz unabh?ngig von Konzentration und anderen Faktoren ist. Das System Amilan-Wasser benimmt sich vollkommen entsprechend dieser Theorie in den studierten Verstreckungs- und Temperaturbereiche. Der Diffusionskoeffizient von Wasser in Amilan konnte daher aus der chemischen Relaxation als Funktion von Dehnung und Temperatur ausgewertet werden. Ein normales Quellungsexperiment wurde für das System bei 40% r. F. und 16,8° C ausgeführt und zeigte, da? die Diffusion von Wasser in Amilan dem Fickschen Gesetz mit konstantem Diffusionskoeffizienten folgt. Beide Diffusionskoeffizienten, der aus chemischer Relaxation und der aus Quellungsdaten gewonnene, stimmten sehr gut überein, falls der erstere auf die Dehnung 0 extrapoliert wurde. Die chemische Relaxation des Systems Polyvinylalkohol-Wasser war merklich anders als nach der Theorie erwartet und lie? in erster Linie vermuten, da? der Diffusionskoeffizient von Wasser in diesem Polymeren nicht konstant ist. Eine entsprechende Andeutung wurde aus Quellungsmessungen an diesem System erhalten. Die Diffusion h?ngt von Konzentration und Zeit ab. Aus diesen Resultaten kann gefolgert werden, da? die Technik der Untersuchungen der chemischen Relaxation unter Verwendung einer geeigneten Theorie nicht nur dazu angewendet werden kann, Diffusionskoeffizienten von kleinen Molekülen in einem gegebenen festen Polymeren zu messen, sondern zumindest auch qualitativ den Typ des Quellungsverhaltens festzustellen, der das System unter den gegebenen experimentellen Bedingungen charakterisiert.相似文献