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61.
Novel synthesis of heterocyclic spirans by tandem cycloaddition to sulfur-containing heterocumulenes
Yoshiki Ohshiro Hitoshi Nanimoto Hiroyuki Tanaka Mitsuo Komatsu Toshio Agawa Noritake Yasuoka Yasushi Kai Nobutami Kasai 《Tetrahedron letters》1985,26(25):3015-3018
Novel Ni(C0)4-promoted tandem cycloadditions of diphenylcyclo- propenone to isothiocyanates and to CS2 were found to provide new heterocyclic spirans, pyrroline-2-one-5-spiro-5′-thiolene-4′-ones and a thiolene-2-one-5-spiro-5′-thiolene-4′-one, respectively, in moderate yields. 相似文献
62.
Summary The sorption property of water vapor by poly(vinyl acetate) (PVAc) of relatively low glass transition temperature (T
g) was studied at temperatures nearT
g.Tcg of humidity-controlled samples of various moisture contents was measured and its variation with the moisture content was determined.T
g of the dry sample was estimated by dilatometry and DSC methods, and to confirm the value, the temperature dependence of mutual diffusion coefficient of the system of water vapor + PVAc was determined. A difference between the sorption mechanisms of water vapor by PVAc at 20 and 30 °C was observed: two sorption mechanisms are involved at 30 °C, while three mechanisms at 20 °C are involved which include the above two and another intermediate one. In earlier stage of sorption, at both 20 and 30 °C, water molecules sorbed by PVAc showed a tendency towards aggregation, while a mixing effect was found at higher stage of the sorption.
With 7 figures 相似文献
Zusammenfassung In der Arbeit werden Wasserdampfsorptionseigenschaften von Polyvinylacetat mit relativ niedriger Glastemperatur (T g) in der Nähe vonT g untersucht. Es wurden Plastizitätseinflüsse und Veränderungen vonT g mit dem Wassergehalt studiert. Es wurde gefunden, daß bei 30 °C ein 2-Stufen-Sorptionsmechanismus, bei 20 °C ein 3-Stufen-Mechanismus existiert.
With 7 figures 相似文献
63.
The method proposed for the evaluation of statistical weights in paper I, and the three-state model [alpha-helical (alpha), extended (epsilon), and other (c) states] formulated in paper II, have been used to develop a procedure to predict the backbone conformations of proteins, based on the concept of the predominant role played by shortrange interactions in determining protein conformation. Conformational probability profiles, in which the probabilities of formation of three consecutive alpha-helical conformations (triad) and of four consecutive extended conformations (tetrad) have been defined relative to their average values over the whole molecule, are calculated for 19 proteins, of which 16 had been used in paper I to evaluate the set of statistical weights of the 20 naturally occurring amino acids. By comparing these conformational probability profiles to experimental x-ray observations, the following results have been obtained: 80% of the alpha-helical regions and 72% of the extended conformational regions have been predicted correctly for the 19 proteins. The percentage of residues predicted correctly is in the range of 53 to 90% for the alpha-helical conformation and in the range of 63 to 88% for the extended conformation for the 19 proteins in the two-state models [alpha-helical (alpha) and other (c) states, and extended (epsilon) and other (c) states]. In the three-state model, the percentage of residues predicted correctly is in the range of 47% to 77 for 19 proteins. These results suggest that the assumption of the dominance of short-range interactions, on which the predictive scheme is based, is a reasonable one. The present predictive method is compared with that of other authors. 相似文献
64.
The effects of self cooling on the apparent kinetics of the nonisothermal dehydration of crushed crystals of lithium sulfate monohydrate were investigated using TG accompanied by DTA and power-compensation type DSC. Linearity of the sample heating rate on the TG-DSC system is much better than that on the TG-DTA. Kinetic obedience and Arrhenius parameters obtained from the TG-DTA deviate considerably from those obtained from the TG-DSC; the latter are the more accurate due to the better linearity of the sample heating rate.
We thank Dr. A. K. Galwey for reading the text and for valuable comments. 相似文献
Zusammenfassung Mittels TG, ergänzt durch DTA und DSC mit Leistungskompensation wurde der Einfluß des Self-cooling-Effektes auf die scheinbare Kinetik der nichtisothermen Dehydratation von zerkleinerten Kristallen aus Lithiumsulfat-Monohydrat geschätzt. Die mittels TG-DTA erhaltene Kinetik und die Arrheniusschen Parameter weichen erheblich von denen ab, die mittels TG-DSC ermittelt wurden. DSC mit Leistungskompensation und TG-DSC haben gegenüber TG oder TG-DTA den großen Vorteil, das nichtisotherme kinetische Verhalten von Feststoffzersetzungen zu charakterisieren. Mittels Thermoanalyse nichtisotherm ermittelte kinetische Parameter sind ohne Anwendung von DSC eher unreell, besonders wenn sie bei größeren Aufheizgeschwindigkeiten und Probengrößen bestimmt wurden.
We thank Dr. A. K. Galwey for reading the text and for valuable comments. 相似文献
65.
Tanaka K Ding MY Helaleh MI Taoda H Takahashi H Hu W Hasebe K Haddad PR Fritz JS Sarzanini C 《Journal of chromatography. A》2002,956(1-2):209-214
In this preliminary study, a new approach to ion-exclusion chromatography is proposed to overcome the relatively poor conductivity detection response which occurs in ion-exclusion chromatography when acids are added to the eluent in order to improve peak shape. This approach, termed vacancy ion-exclusion chromatography, requires the sample to be used as eluent and a sample of water to be injected onto a weakly acidic cation-exchange column (TSKgel OApak-A). Vacancy peaks for each of the analytes appear at the retention times of these analytes. Highly sensitive conductivity detection is possible and sharp, well-shaped peaks are produced, leading to efficient separations. Retention times were found to be affected by the concentration of the analytes in the eluent, and also by the presence of an organic modifier such as methanol in the eluent. Detection limits for oxalic, formic, acetic, propionic, butyric and valeric acids were 0.1, 0.2, 0.3, 0.3, 0.4 and 0.5 microM, respectively, and linear ranges for some acids extended over two orders of magnitude. Precision values for retention times were 0.21% and for peak areas were <1.90%. The vacancy ion-exclusion chromatography method was found to give detection responses four to 10 times higher than conventional ion-exclusion chromatography using sulfuric acid eluent and two to five times higher than conventional ion-exclusion chromatography using benzoic acid eluent. 相似文献
66.
Tanaka T Teramura K Arakaki K Funabiki T 《Chemical communications (Cambridge, England)》2002,(22):2742-2743
Photoassisted selective catalytic reduction of NO with ammonia (photo-SCR) at low temperature over irradiated TiO2 in a flow reactor was confirmed to proceed efficiently and the adsorbed ammonia reacted with NO under irradiation of TiO2. 相似文献
67.
Koichi Tanaka Hideyuki Takano Zofia Urbanczyk-lipkowska 《Journal of inclusion phenomena and macrocyclic chemistry》2006,56(3-4):281-285
The host compounds 1,1’-binaphthyl-2,2′-dihydroxy-5,5′-dicarboxylic acid (1) and 1,1′-binaphthyl-2,2′-dihydroxy-6,6′-dicarboxylic acid (2) have been synthesized, and their inclusion properties have been studied. Inclusion complexes formed by 1 and 2 with volatile guests such as acetone and methanol release the guests only at much higher temperatures than their boiling
points. The crystal structures of the inclusion complexes have been determined from single crystal X-ray diffraction data
and show different host lattices. 相似文献
68.
Nobuyuki Tanaka 《Journal of Thermal Analysis and Calorimetry》1996,46(3-4):1021-1031
The instantaneous elastic moduli for a nylon-6 monofilament were derived on strain recoveries right after creep, stress relaxation, and rapid elongation,E
c
,E
s
andE
e
, respectively. It was found that during strain recoveryE
s
(>E
e
) andE
e increase monotonically with increasing load,m
1, on the sample. The extrapolated value of Es atm
1=0 g is almost equal to Young's modulus, 4.06 GPa. The value ofE
c also increased with increasingm
1, and atm
1=600 g (1.93 t cm–2) reached about 14 GPa. The endothermic heat change right after creep, stress relaxation or rapid elongation,Q, was negligibly small. For comparison,E
s
,E
c
andQ were also investigated for silicone rubber. It was found thatE
s (53.8 M Pa at the draw ratioD=1.2) decreased abruptly atD=1.3. In the range ofD=1.4–1.9,E
s was only 22.6 MPa. In the case of stress relaxation,Q increased with increasingD from 4 J mol–1 (atD=1.2) to 56 J mol–1 (atD=1.9). FurthermoreE
c (5.58 MPa atm
1=133.8 g (429.4 kg cm–2)) increased gradually with increasing m1 and attained 16.6 MPa atm
1=548.4 g (1.76 t cm–2). In the case of creep,Q was in the range of 0–11.5 J mol–1 and larger when larger loads,m
2 were removed during the later stages of creep.Dedicated to Professor Bernhard Wunderlich on the occasion of his 65th birthdayThe author wishes to thank Mr. Keizi Igarashi and Mr. Tetsuya Yasui for helping in the experiments. 相似文献
69.
I Kanamori S Nakano F Tanaka M Hurukawa M Yanase Y Shinozuka C Higuchi Y Okumura 《Radioisotopes》1988,37(6):347-350
An IgE RIA kit (Sandwich method; Dainabott), is used to obtain the following results. (1) Standard curve: Since the range of reproduction rate show 3.16-7.07% (C.V.), the curve become steep. (2) Incubations under controlled situation: Both of the incubations are controlled at 15-30 degrees C for 2 h. (3) Reproducibility test: Coefficients of variation (C.V.) of intra-assay and inter-assay variation are 2.32-3.94% and 2.92-3.92% respectively. (4) Recovery test: A result of the recovery test range between 100.1-101.7%. (5) Dilution test: Multiple dilution effects are observed. (6) Average counts of the serum IgE for the controlled and diseased groups: The average counts of the serum IgE for the controlled group, atopic diseased group, allergic rhinitis group and allergic bronchial asthma are 144.9 +/- 183.2 IU/ml, 1,099.0 +/- 2,782.4 IU/ml, 1,150.9 +/- 2,063.3 IU/ml and 600.7 +/- 686.4 IU/ml respectively. The value of the diseased groups have tendency to show higher averages than the controlled group. Since the controlled and diseased groups show wide distributions of the serum IgE level, there is no significant difference of two variations. However the diseased groups have tendency to show higher ratio of the serum IgE level in blood than the controlled groups. These basic researches are quite meaningful, because they are able to apply for a supplemental diagnosis of the atopic and parasitic disease. 相似文献
70.
Masaaki Sakakibara Yoko Yonemura Zenzo Tanaka Hiroatsu Matsuura Hiromu Murata 《Journal of Molecular Structure》1981
The Raman and IR spectra of 1,5-dichloro- and 1,5-dibromopentanes and 1,6-dichloro-and 1,6-dibromohexanes have been measured. The normal coordinates have been calculated for these molecules using a consistent set of force constants and the molecular conformations studied by analysing the spectra with reference to the results of the calculations. In the crystalline solid state, 1,5-dichloropentane assumes the trans-trans-trans-gauche form and 1,5-dibromopentane, 1,6-dichloro- and 1,6-dibromohexanes assume the all-trans form. The normal coordinate treatment with the well-established force field was of great help in determining the whole molecular form of the relatively large chain molecules. 相似文献