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61.
A new force approach is reported in which we improve the wavefunction so that the Hellmann-Feynman theorem is satisfied. A sufficient condition for the Hellmann-Feynman theorem to be satisfied is that the basis set includes AO derivatives ?xr/?xrfor any basis xr. Here we test a procedure in which only the first derivative AOs are added to the “parent” AOs. The results are very encouraging. 相似文献
62.
Hiroshi Tanaka Toru Masuko Keisuke Homma Saburo Okajima 《Journal of polymer science. Part A, Polymer chemistry》1969,7(7):1997-2006
Polypropylene films of various isotacticities and crystallinities were stretched biaxially in one step in air at 140–152°C or polyaxially in poly(ethylene glycol) at 130–160°C, and the morphological changes were studied by electron microscopy (replica). In the initial stage of stretching, with vA = 1.4, the spherulites of one of the films used for the experiment were broken both from the centers and boundaries, and those of another film were broken mainly from the center. This difference in the deformation behavior seems to be characteristic of the film properties and independent of the method of stretching, although the factors involved are still unknown. On further stretching (vA = 22), well annealed spherulites were broken into many small blocklike fragments with unfolded fibrils running among them, particularly at the low stretching temperature (140°C), and fibrillation proceeded at the expense of the residual fragments. In the case of quenched or slightly crystallized material, the fragments were dendritic and divided into finer and finer fibrils on stretching. At elevated temperature, however, even for well annealed spherulites, the deformation behavior resembles that of the quenched material, and at a high degree of stretching the spherulites take on the fibrillar net structure in every case. In films containing a high amount of atactic fraction, radial, tangential, and boundary cracking occurred more easily, and broad fibrils were observed across the cracks. 相似文献
63.
Hiroshi Mitsui Yuichi Shimizu 《Journal of polymer science. Part A, Polymer chemistry》1979,17(9):2805-2813
A kinetic study was made of the formation of hydrogen and trans-vinylene unsaturation in the radiolysis of polyethylene induced by γ rays with a dose rate of 6.35 × 105 rad/hr at 30–100°C in vacuo. The rates of the formation of hydrogen and trans-vinylene unsaturation were described by the zero-order formation kinetics with respect to each concentration combined with the first-order disappearance. The apparent rate constant for the formation of hydrogen increased gradually with rising irradiation temperature to give the activation energy of 0.6 kcal/mole. On the other hand, those for the disappearance of hydrogen and the formation and disappearance of trans-vinylene unsaturation were almost independent of temperature. The G values for crosslinking and main-chain scission were obtained from the gel data by using the Charlesby-Pinner equation, and the activation energy of 1.5 kcal/mole was given for both of them. On the basis of these results the reactions induced by γ rays in solid polyethylene were discussed. 相似文献
64.
2-Chlorotropone reacts with 6,6-dimethylfulvene to form a 1:1 adduct only. From kinetic data as well as from structural evidence the conclusion was drawn that the [6+4] cycloidditions between tropones and cyclopentadiene or fulvenes are highly disfavoured by substituents at the reaction center. 相似文献
65.
Tsuneki Ichikawa Ken-ichi Oyama Tatsu Kondoh Hiroshi Yoshida 《Journal of polymer science. Part A, Polymer chemistry》1994,32(13):2487-2492
Effect of irradiation temperature on the main-chain scission of poly (methyl methacrylate) (PMMA) caused by γ-irradiation was studied by means of gel permeation chromatography and ESR spectroscopy. Although no temperature dependency was observed on the scission efficiency for purified PMMA, the efficiency for crude or monomer-doped purified PMMA was decreased by decreasing the temperature below ca. 200 K. Above 200 K the efficiency was constant and did not depend on the purity of PMMA. ESR study of the irradiated PMMA revealed that the suppression of the scission below 200 K is induced by the addition of methyl methacrylate monomer to primary radical species, which otherwise cause the main-chain scission by warming the polymer above 200 K. The primary radical generated above 200 K immediately converts to the scission-type ? CH2 ? ?(CH3) COOCH3 radical through the β-scission of the polymer main chain, so that the efficiency of the scission does not depend on both the impurity and the irradiation temperature. © 1994 John Wiley & Sons, Inc. 相似文献
66.
Mavis M. Kadooka Mildred Y. Chang Hiroshi Fukami P.J. Scheuer Jon Clardy Barbara A. Solheim James P. Springer 《Tetrahedron》1976,32(8):919-924
From the bark of the endemic Hawaiian tree Sophora chrysophylla Seem. we have isolated two unprecedented quainolizidine alkaloids, mamanine (4) and pohakuline (5). Both bases are 1-hydroxymethylenequinolizidines which are linked at C-3 to α-pyridone or α-piperidone moieties. The alkaloids may be intermediates in a heretofore unknown biogenetic pathway of Sophora alkaloids. 相似文献
67.
Hiroshi Ueyama 《Journal of statistical physics》1980,22(1):1-26
Based on the assumption of a kinetic equation in space, a stochastic differential equation of the one-particle distribution is derived without the use of the linear approximation. It is just the Boltzmann equation with a Langevin-fluctuating force term. The result is the general form of the linearized Boltzmann equation with fluctuations found by Bixon and Zwanzig and by Fox and Uhlenbeck. It reduces to the general Landau-Lifshitz equations of fluid dynamics in the presence of fluctuations in a similar hydrodynamic approximation to that used by Chapman and Enskog with respect to the Boltzmann equation.This work received financial support from the Alexander von Humboldt Foundation. 相似文献
68.
Kaori Suzuki Takayoshi Kobayashi Hiroyuki Ohtani Hiroshi Yesaka Saburo Nagakura Yoshinori Shichida Tôru Yoshizawa 《Photochemistry and photobiology》1980,32(6):809-811
Difference spectra between squid rhodopsin and its bathorhodopsin at room temperature were measured ca. 150 ps and ca. 500 ps after the excitation at 347.2 nm by a double-beam picosecond time-resolved spectrometer. The spectra measured showed a red shift of the isosbestic point between squid rhodopsin and its bathorhodopsin and a lower ΔAmax/ΔAmin value compared with those measured at low temperatures by conventional spectrophotometry. 相似文献
69.
Takushi Kurihara Mariko Sugiyama Hiroshi Hirano Ken-Ichi Tomita Masayoshi Sakaki 《Journal of heterocyclic chemistry》1975,12(3):541-545
Reaction of o-nitrobenzylideneacetylacetone ( 1a ) with hydrazine dihydrochloride in methanol gave 4-(α-methoxy-o-nitrobenzyl)-3,5-dimethylpyrazole hydrochloride ( 4a ), whose structure was unambigously confirmed by an X-ray crystallographic analysis, via 4-(o-nitrobenzylidene)-3,5-dimethylisopyrazole ( 2a ). Compound 2a was synthesized by condensation of 1a with hydrazine dihydrochloride in acetonitrile. Analogously the corresponding o-chloro derivatives ( 2b, 4b ) were obtained. These were converted to N-methyl ( 6b ) and N-acetyl ( 7a,b ) derivatives and the behaviors on bromination and pyrolysis were investigated. 相似文献
70.
Masahiro Fujita Hiroshi Egawa Katsumi Chiba Jun-Ichi Matsumoto 《Journal of heterocyclic chemistry》1997,34(6):1731-1735
The one-pot reaction of ethyl 1-cyclopropyl-6,7,8-trifluoro-1,4-dihydro-4-oxoquinoline-3-carboxylate ( 6 ) with tert-butyl acetoacetate gave 3-tert-butyl 7-ethyl 9-cyclopropyl-4-fluoro-6,9-dihydro-2-methyl-6-oxofuro[3,2-h]quinoline-3,7-dicarboxylate ( 5 ). This regioselective cyclization was rationalized by the Hard and Soft Acids and Bases principle. By use of a similar furan-forming reaction, we prepared 2-(amino-methyl)furo[3,2-h]quinoline-7-carboxylic acid 4 . Compound 4 showed weak antibacterial activity. 相似文献