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1.
D. Amutha Rani Y. Yamamoto S. Mohri M. Sivakumar Y. Tsujita H. Yoshimizu 《Journal of Polymer Science.Polymer Physics》2003,41(3):269-273
In this study, a novel stepwise extraction method has been examined. The guest molecules housed between the helices of the clathrate δ form of syndiotactic polystyrene can be removed completely with this method. A systematic study of the preparation of a solvent‐free mesophase (emptied clathrate) membrane, its helical and residual solvent contents, and its structural transformations has been performed. In this first attempt, an enhancement in the TTGG helical content has been observed in the extracted membrane, and a conceptual mechanism is proposed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 269–273, 2003 相似文献
2.
S. Mohri D. Amutha Rani Y. Yamamoto Y. Tsujita H. Yoshimizu 《Journal of Polymer Science.Polymer Physics》2004,42(2):238-245
Syndiotactic polystyrene (sPS) has various crystalline forms such as α, β, γ, and δ forms, and a mesophase depending on the preparation method. In this study, we focused on the mesophase with the molecular cavity of sPS, which is obtained by step‐wise extraction of the guest molecules from the sPS δ form. To prepare the mesophase containing different shapes and sizes of the cavity, two kinds of the sPS δ form membrane cast from either toluene or chloroform solution were first prepared and then the guest molecules were removed by a step‐wise extraction method using acetone and methanol. We could succeed in the preparation of two kinds of mesophase with different shapes and sizes of the molecular cavity. Either toluene or chloroform vapor sorption to the sPS mesophase membranes was examined at 25 °C. Sorption analysis indicates that the mesophase with large molecular cavities can mainly sorb large molecules; on the other hand, the mesophase with small cavities can sorb only the small molecules, and is unable to sorb a large amount of large molecule because the cavity was too small to sorb the large molecules. Therefore, the sPS mesophase membrane has sorption selectivity based on the size of the molecular cavity. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 238–245, 2004 相似文献
3.
Tomoko Nii Akira Takamura Kiminori Mohri Fumiyoshi Ishii 《Colloids and surfaces. B, Biointerfaces》2003,27(4):436-332
We examined hydrogenated purified egg yolk lecithins, having practical advantages over non-hydrogenated ones, as liposomal membrane materials. Liposomes were prepared by the microencapsulation vesicle (MCV) method in which liposomes are formed through two-step emulsification and dispersion. Three types of purified egg yolk lecithins with different iodine values were examined after being dissolved in one of three lipid solvents. The liposome size increased as the temperature during the second emulsification increased, being closer to the boiling temperature of the solvent. The preparation temperature in relation to the transition temperature of each lecithin was also a factor affecting liposome sizes. As for the encapsulation efficiencies of the model compound calcein in liposomes, they differed mainly depending on the solubility of each lecithin in a lipid solvent and it was more obvious in hydrogenated lecithins. A high preparation temperature resulted in lower encapsulation efficiencies, suggesting that leakage of encapsulated calcein was facilitated at high temperature in the MCV methods. There was a significant correlation between liposome sizes and encapsulation efficiencies in non-hydrogenated purified egg yolk lecithin but not in hydrogenated ones. When using hydrogenated purified egg yolk lecithins as liposomal membrane materials, it was suggested that a lipid solvent should be chosen so that a lecithin completely dissolves under the preparation condition in order to achieve a higher encapsulation efficiency. Smaller liposome particles were obtained when the second emulsification was performed at a lower temperature compared with the boiling point of the lipid solvent. These findings can be applied to control encapsulation efficiencies and particle sizes in each particular liposome preparation enclosing therapeutic agents. 相似文献
4.
Mohri K Yokoyama K Komiya H Watanabe Y Yoshida Y Isobe K Tsuda Y 《Chemical & pharmaceutical bulletin》2003,51(5):502-507
Two new dioxopyrrolines (1-aryl-4-methoxycarbonyl-1H-pyrrole-2,3-dione 6 and the 5-methoxycarbonyl isomer 8) behaved as good dienophiles to some kind of 1,3-dienes examined. In most cases, the products were explained by the reaction where the largest lobe of HOMO of dienes reacted to the larger LUMO of dienophiles in an expected cis-endo manner. However, in the reactions of 8 with alkylbutadienes, piperylene and isoprene, abnormality in the reaction was observed, which was well explained by taking account of steric factors. 相似文献
5.
In the Sc2O3---Ga2O3---CuO, Sc2O3---Ga2O3---ZnO, and Sc2O3---Al2O3---CuO systems, ScGaCuO4, ScGaZnO4, and ScAlCuO4 with the YbFe2O4-type structure and Sc2Ga2CuO7 with the Yb2Fe3O7-type structure were obtained. In the In2O3---A2O3---BO systems (A: Fe, Ga, or Al; B: Mg, Mn, Fe, Ni, or Zn), InGaFeO4, InGaNiO4, and InFe3+MgO4 with the spinel structure, InGaZnO4, InGaMgO4, and InAlCuO4 with the YbFe2O4-type structure, and In2Ga2MnO7 and In2Ga2ZnO7 with the Yb2Fe3O7-type structure were obtained. InGaMnO4 and InFe2O4 had both the YbFe2O4-type and spinel-type structures. The revised classification for the crystal structures of AB2O4 compounds is presented, based upon the coordination numbers of constituent A and B cations. 相似文献
6.
N. Kuroda S. Ulmer D. J. Murtagh S. Van Gorp Y. Nagata M. Diermaier S. Federmann M. Leali C. Malbrunot V. Mascagna O. Massiczek K. Michishio T. Mizutani A. Mohri H. Nagahama M. Ohtsuka B. Radics S. Sakurai C. Sauerzopf K. Suzuki M. Tajima H. A. Torii L. Venturelli B. Wünschek J. Zmeskal N. Zurlo H. Higaki Y. Kanai E. Lodi Rizzini Y. Nagashima Y. Matsuda E. Widmann Y. Yamazaki 《Hyperfine Interactions》2015,235(1-3):13-20
In order to test CPT symmetry between antihydrogen and its counterpart hydrogen, the ASACUSA collaboration plans to perform high precision microwave spectroscopy of ground-state hyperfine splitting of antihydrogen atom in-flight. We have developed an apparatus (“cusp trap”) which consists of a superconducting anti-Helmholtz coil and multiple ring electrodes. For the preparation of slow antiprotons and positrons, Penning-Malmberg type traps were utilized. The spectrometer line was positioned downstream of the cusp trap. At the end of the beamline, an antihydrogen beam detector was located, which comprises an inorganic Bismuth Germanium Oxide (BGO) single-crystal scintillator housed in a vacuum duct and surrounding plastic scintillators. A significant fraction of antihydrogen atoms flowing out the cusp trap were detected. 相似文献
7.
K. Yatsui M. Yatsuzuka T. Fujii M. Yokoyama M. Masuzaki T. Tsuzuki K. Narihara A. Mohri 《Physics letters. A》1979,73(4):321-323
We study experimentally the interaction of a current-modulated relativistic electron beam with a mirror-confined plasma. A high-power transmitter (500 MHz, 1 GW) is developed. Rapid heating takes place up to ≈ 900 eV, which is interpreted as a lower-hybrid parametric instability. 相似文献
8.
Fumihito Mohri Alexander A. Granovsky 《International journal of quantum chemistry》2008,108(3):544-557
A simple molecular orbital model has been applied to explanation of the B? N bond shortening in H3BNH3 on going from the gaseous to the solid state. In this model, the shortening is attributed to the bond order increase that is caused by the fact that each atom in the crystal experiences different external electrostatic potential to each other and thus the orbital energy level of each atom is changed. To illustrate this model, Effective Fragment Potential (EFP) method has been applied to the system consisting of a H3BNH3 molecule and 30 dipole moments whose magnitudes are determined by Lorentz's local field theory. This EFP computation has brought significant B? N bond shortening (1.668 → 1.623 Å), which is about 50% of the actual shortening. The factor of the remaining discrepancy has been analyzed by Morokuma decomposition under EFP and localized orbital analysis. These analyses have revealed that the remaining discrepancy is almost compensated by incorporating the dihydrogen bonds (B? H···H? N) that are formed by the orbital interaction between the bonding orbital of the B? H and the antibonding orbital of the N? H. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 相似文献
9.
An enantioselective total synthesis of sacrolide A, an antimicrobial and cytotoxic fourteen-membered macrolactonic oxylipin isolated from an edible freshwater cyanobacterium, has been accomplished from a known carboxylic acid in 20% overall yield by a concise ten-step sequence. The key transformations include chiral oxazolidinone-based diastereoselective installation of two hydroxy-bearing stereocenters, the Horner–Wadsworth–Emmons olefination to construct the full carbon skeleton, and the Shiina macrolactonization to establish the fourteen-membered macrolide structure. 相似文献
10.
Kazuyo Shigematsu Kiyohisa Imada Motowo Takayanagi 《Journal of Polymer Science.Polymer Physics》1975,13(1):73-86
Extrudates of solid linear polyethylene prepared under proper pressure and temperature conditions have a high c axis orientation along the extrusion direction, with lamellar crystals and amorphous layers stacked alternately along the extrusion direction. Kink bands were formed by compressing the oriented extrudate at room temperature along the extrusion direction. Inspection of the kink bands by wide-angle and small-angle x-ray diffraction and electron microscopy revealed that the fiber axis was rotated from the original axis direction by 70–75° and that the lamellar crystals were inclined to the fiber axis in the kink band by 55–60° and stacked nearly parallel to the kink boundary. The superstructural change during the formation of the kink band could not be interpreted in terms of uniform c axis shear alone. In addition to such a mechanism, it was necessary to take into account intermicrofibril and/or intercrystallite slip. 相似文献