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251.
252.
Saito Kazuya Ikeda Mayumi Sorai Michio 《Journal of Thermal Analysis and Calorimetry》2002,70(2):345-352
Meaning of the alkyl chain-length dependence of transition entropy in liquid crystal is discussed and clarified in a long-chain
region. A method to deduce contributions of the alkyl chain and the molecular core is proposed. Application of the method
suggests that, in most smectic A (SmA) - nematic (N) phase transitions, not only a molecular core (modeled by a hard-rod)
but also a (terminal) alkyl chain is disordered upon the SmA→N transition.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
253.
Michio Kimura 《Journal of heterocyclic chemistry》1987,24(1):283-288
The reaction of 1-naphthol or phenol derivatives with oxalic and sulfuric acids yielded novel spirolactones. Eight examples ( 2a-h ) were synthesized by this reaction. The structures of the spirolactones were established from spectral evidence and the X-ray diffraction studies. Some of the spirolactones form the solvates with the aromatic solvent molecules, such as toluene, xylene and nitrobenzene, and the structure of the nitrobenzene solvate of 2a was determined by the X-ray analysis. 相似文献
254.
The Unanticipated Dimerization of Ce@C2v(9)‐C82 upon Co‐crystallization with Ni(octaethylporphyrin) and Comparison with Monomeric M@C2v(9)‐C82 (M = La,Sc, and Y) 下载免费PDF全文
Prof. Mitsuaki Suzuki Prof. Michio Yamada Prof. Yutaka Maeda Dr. Satoru Sato Prof. Yuta Takano Prof. Filip Uhlík Prof. Zdenek Slanina Prof. Yongfu Lian Prof. Xing Lu Prof. Shigeru Nagase Prof. Marilyn M. Olmstead Prof. Alan L. Balch Prof. Takeshi Akasaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(50):18115-18122
We report that Ce@C2v(9)‐C82 forms a centrosymmetric dimer when co‐crystallized with Ni(OEP) (OEP = octaethylporphyrin dianion). The crystal structure of {Ce@C2v(9)‐C82}2?2[Ni(OEP)]?4 C6H6 shows that a new C?C bond with a bond length of 1.605(5) Å connects the two cages. The high spin density of the singly occupied molecular orbital (SOMO) on the cage and the pyramidalization of the cage are factors that favor dimerization. In contrast, the treatment of Ni(OEP) with M@C2v(9)‐C82 (M = La, Sc, and Y) results in crystallization of monomeric endohedral fullerenes. A systematic comparison of the X‐ray structures of M@C2v(9)‐C82 (M = Sc, Y, La, Ce, Gd, Yb, and Sm) reveals that the major metal site in each case is located at an off‐center position adjacent to a hexagonal ring along the C2 axis of the C2v(9)‐C82 cage. DFT calculations at the M06‐2X level revealed that the positions of the metal centers in these metallofullerenes M@C2v(9)‐C82 (M = Sc, Y, and Ce), as determined by single‐crystal X‐ray structure studies, correspond to an energy minimum for each compound. 相似文献
255.
The phase transition behaviour of an optically isotropic, thermotropic cubic mesogen 1,2-bis-(4-n-octyloxybenzoyl)hydrazine, BABH(8), was investigated under pressures up to 200 MPa using a high pressure differential thermal analyser, wide-angle X-ray diffraction and a polarizing optical microscope equipped with a high pressure optical cell. The phase transition sequence, low temperature crystal (Cr2)-high temperature crystal (Cr 1)- cubic (Cub)-smectic C (SmC)-isotropic liquid (I) observed at atmospheric pressure, is seen in the low pressure region below about 30 MPa. The cubic phase disappears at high pressures above 30–40 MPa, in conjunction with the disappearance of the Cr1 phase. The transition sequence changes to Cr2-SmC-I in the high pressure region. Since only the Cub-SmC transition line among all the phase boundaries has a negative slope (dT/dP) in the temperature-pressure phase diagram, the temperature range for the cubic phase decreases rapidly with increasing pressure. As a result, a triple point was estimated approximately as 31.6 ±2.0 MPa, 147.0±1.0°C for the SmC, Cub and Cr1 phases, indicating the upper limit of pressure for the observation of the cubic phase. Reversible changes in structure and optical texture between the Cub and SmC phases were observed from a spot-like X-ray pattern and dark field for the cubic phase to the Debye-Sherrer pattern and sand-like texture for the SmC phase both in isobaric and isothermal experiments. 相似文献
256.
Tsuguto Imaeda Tamotsu Hashimoto Satoshi Irie Michio Urushisaki Toshikazu Sakaguchi 《Journal of polymer science. Part A, Polymer chemistry》2013,51(8):1796-1807
ABA‐type triblock copolymers and AB‐type star diblock copolymers with poly(2‐adamantyl vinyl ether) [poly(2‐AdVE)] hard outer segments and poly(n‐butyl vinyl ether) [poly(NBVE)] soft inner segments were synthesized by sequential living cationic copolymerization. Although both the two polymer segments were composed solely of poly(vinyl ether) backbones and hydrocarbon side chains, they were segregated into microphase‐separated structure, so that the block copolymers formed thermoplastic elastomers. Both the ABA‐type triblock copolymers and the AB‐type star diblock copolymers exhibited rubber elasticity over wide temperature range. For example, the ABA‐type triblock copolymers showed rubber elasticity from about ?53 °C to about 165 °C and the AB‐type star diblock copolymer did from about ?47 °C to 183 °C with a similar composition of poly(2‐AdVE) and poly(NBVE) segments in the dynamic mechanical analysis. The AB‐type star diblock copolymers exhibited higher tensile strength and elongation at break than the ABA‐type triblock copolymers. The thermal decomposition temperatures of both the block copolymers were as high as 321–331 °C, indicating their high thermal stability. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
257.
Akimaro Kawahara Michio Sadatomi Fuminori Matsuyama Hidetoshi Matsuura Mayo Tominaga Masanori Noguchi 《Experimental Thermal and Fluid Science》2009,33(5):883-894
This paper is concerned with the prediction of micro-bubble dissolution characteristics in water and seawater when microbubbles are generated by a Sadatomi-type micro-bubble generator (2003) with a spherical body in a flowing liquid tube. In the experiments, in order to know the effects of the salinity on the characteristics, tap water and an artificial seawater with different salt concentrations of 1 and 3 wt% were used as the test liquids. Parameters measured were the Sauter mean diameter of bubbles, dBS, the void fraction, α, the rising velocity of bubbles, uG, the interfacial area concentration, a, the volumetric mass transfer coefficient, KLa, and the liquid-side mass transfer coefficient, KL. In the analysis, for predicting α, KLa and KL, some correlations in the literatures were tested against the present data. Furthermore, in order to improve the predictability, new correlations were developed based on the present data. The prediction of KLa with the new correlation agreed well with Nishino et al.’s [T. Nishino, K. Terasaka, M. Ishida, Application for several micro-bubble generators for gas absorber, in: Proceedings of the Annual Meeting of the Japanese Society for Multiphase Flow, 2006, pp. 276–277 (in Japanese)] and Li and Tsuge’s [P. Li, H. Tsuge, Water treatment by induced air flotation using microbubbles, Journal of Chemical Engineering of Japan 39 (2006) 896–903; P. Li, H. Tsuge, Ozone transfer in a new gas-induced contactor with microbubbles, Journal of Chemical Engineering of Japan 39 (2006) 1213–1220] data for different aeration systems using several different micro-bubble generators. 相似文献
258.
Jacek Przepiórski Justyna Karolczyk Tomoki Tsumura Masahiro Toyoda Michio Inagaki Antoni W. Morawski 《Journal of Thermal Analysis and Calorimetry》2012,107(3):1147-1154
Mixtures of poly(ethylene terephthalate) (PET) with magnesium compounds including carbonate, hydroxide, and oxide, with different
weight ratios of the components, were subjected to thermogravimetric measurements up to 850 °C in argon atmosphere. For reference,
pure components of the examined mixtures were analyzed at the same conditions. During the heating, PET underwent carbonization
and magnesium carbonate and hydroxide decomposed to MgO with evolution of gaseous products (CO2 and/or H2O). As found, carbon yields calculated from the residual masses depended on the qualitative and quantitative composition of
the starting mixture. Yields of carbon obtained from PET mixed with MgO did not depend on MgO/PET ratio. However, yields of
carbon formed through pyrolysis of PET contained in the mixture with either magnesium carbonate or magnesium hydroxide were
in general higher and depended on the weight ratio of components in the starting material. Reasons of these inconsistent results
are discussed and explained. An influence of gasification of char on the carbon yield is explained. 相似文献
259.
Gerald R. Van Hecke Corresponding author Tadahiro Nakamoto Todd G. Clements Michio Sorai 《Liquid crystals》2013,40(7):831-837
The heat capacity of the metallomesogen purple cobalt stearate Co(O2CC17H35)2 has been measured by adiabatic calorimetry at temperatures between 16 and 420?K. This compound exhibits two crystalline phases (low temperature Cr2 and high temperature Cr1 phases), mesophase (M phase), and isotropic liquid (I phase). A third crystalline phase Cr3, which is entirely metastable with respect to all the others, is suggested by DSC studies. The Cr2-to-Cr1, Cr1-to-M, and M-to-I phase transitions occurred at 362.1, 380.9, and 400.4?K, respectively. The enthalpy and entropy gains at these phase transitions were determined. The mesophase is either smectic A or nematic. 相似文献
260.
Tamotsu Hashimoto Ayumi Takahashi Michio Urushisaki Toshikazu Sakaguchi 《Journal of polymer science. Part A, Polymer chemistry》2010,48(7):1641-1648
Hydroxy‐terminated telechelic poly(vinyl ether)s with pendant oxyethylene chains were synthesized by the reaction of the CH3CH(OCOCH3)? O[CH2]4O? CH(OCOCH3)CH3/Et1.5AlCl1.5/THF‐based bifunctional living cationic polymers of 2‐methoxyethyl vinyl ether (MOVE), 2‐ethoxyethyl vinyl ether (EOVE), and 2‐(2‐methoxyethoxy)ethyl vinyl ether (MOEOVE) with water and the subsequent reduction of the aldehyde polymer terminals with NaBH4. The obtained poly(vinyl ether) polyols were reacted with an equimolar amount of toluene diisocyanates [a mixture of 2,4‐ (80%) and 2,6‐ (20%) isomers] to give water‐soluble polyurethanes. The aqueous solutions of these polyurethanes caused thermally induced precipitation at a particular temperature depending on the sort of the thermosensitive poly(vinyl ether) segments containing oxyethylene side chains. These polyurethanes also function as polymeric surfactants, lowered the surface tension of their aqueous solutions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1641–1648, 2010 相似文献