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161.
Two polycatenar materials composed of a four-aromatic-ring core with a perfluorinated moiety attached in one terminal position through either butylene- or pentylene spacer groups, and three tetradecyloxy chains at the other end (abbreviated as 14PC4F and 14PC5F), were investigated to study the effect of pressure on the phase transition behaviour. A polarizing optical microscope equipped with a high pressure optical hot stage, was used for the purpose. The T vs. P phase diagrams of 14PC4F and 14PC5F were constructed in the pressure region up to 100 MPa. 14PC4F showed the stable crystal (Cr1)-columnar tetragonal (Coltet)-smectic A (SmA)-columnar hexagonal (Colh)-isoropic liquid (I) phase transition sequence under all pressures. 14PC5F exhibited the phase sequence metastable crystal (Cr2)-cubic (Cub)-Coltet-SmA-I in a melt-cooled sample on heating under pressure. But when the melt-cooled Cr2 sample was annealed at 52-54°C for 2-3 h, the stable crystal (Cr1) was formed slowly, giving a stable Cr1-Cub-Coltet-SmA-I phase sequence. The temperature region of the stable cubic phase broadened with increasing pressure. Furthermore a new mesophase of 14PC5F was pressure-induced between the I and SmA phases on cooling at pressures above about 16 MPa. Since the monotropic mesophase exhibited a texture very similar to that of the high temperature Colh phase of 14PC4F with planar orientation, the new phase was assigned at a high temperature columnar hexagonal phase of 14PC5F. 相似文献
162.
163.
164.
Yuichi Terui Chu YiwenLi Jun-ying Tsutomu AndoHaruaki Yamamoto Yoji KawamuraYasumitsu Tomishima Saeko UchidaTadayasu Okazaki Eiji MunetomoTakayuki Seki Koji YamamotoShigeru Murakami Akira Kawashima 《Tetrahedron letters》2003,44(29):5427-5430
In the course of our screening program to identify inhibitors of HSP47 gene expression, we obtained a novel aromatic substance from Streptomyces sp. named Xantholipin. Its structure was determined based on physicochemical data of Xantholipin and its derivatives. The absolute configuration was also established by the modified Mosher's method. 相似文献
165.
Yoji Miyajima Shin-ya Komatsu Masatoshi Mitsuhara Satoshi Hata Hideharu Nakashima Nobuhiro Tsuji 《哲学杂志》2015,95(11):1139-1149
Microstructural changes, such as the density of grain boundary (GB) and dislocation density, due to isochronal annealing in severely plastic-deformed commercial purity aluminium up to 523 K was evaluated using electrical resistivity measurements and scanning transmission electron microscopy. Eventually, the GB density decreases from about 7.2 × 106 to about 2 × 106 m?1, whilst the dislocation density decreases from an initial value of around 1.3 × 1014 m?2 down to around 4 × 1013 m?2. 相似文献
166.
Two polycatenar materials composed of a four‐aromatic‐ring core with a perfluorinated moiety attached in one terminal position through either butylene‐ or pentylene spacer groups, and three tetradecyloxy chains at the other end (abbreviated as 14PC4F and 14PC5F), were investigated to study the effect of pressure on the phase transition behaviour. A polarizing optical microscope equipped with a high pressure optical hot stage, was used for the purpose. The T vs. P phase diagrams of 14PC4F and 14PC5F were constructed in the pressure region up to 100 MPa. 14PC4F showed the stable crystal (Cr1)–columnar tetragonal (Coltet)–smectic A (SmA)–columnar hexagonal (Colh)–isoropic liquid (I) phase transition sequence under all pressures. 14PC5F exhibited the phase sequence metastable crystal (Cr2)–cubic (Cub)–Coltet–SmA–I in a melt‐cooled sample on heating under pressure. But when the melt‐cooled Cr2 sample was annealed at 52–54°C for 2–3 h, the stable crystal (Cr1) was formed slowly, giving a stable Cr1–Cub–Coltet–SmA–I phase sequence. The temperature region of the stable cubic phase broadened with increasing pressure. Furthermore a new mesophase of 14PC5F was pressure‐induced between the I and SmA phases on cooling at pressures above about 16 MPa. Since the monotropic mesophase exhibited a texture very similar to that of the high temperature Colh phase of 14PC4F with planar orientation, the new phase was assigned at a high temperature columnar hexagonal phase of 14PC5F. 相似文献
167.
Direct Synthesis of Chromium Perovskite Oxyhydride with a High Magnetic‐Transition Temperature 下载免费PDF全文
Dr. Cédric Tassel Yoshihiro Goto Yoshinori Kuno Dr. James Hester Prof. Mark Green Dr. Yoji Kobayashi Prof. Hiroshi Kageyama 《Angewandte Chemie (International ed. in English)》2014,53(39):10377-10380
We report a novel oxyhydride SrCrO2H directly synthesized by a high‐pressure high‐temperature method. Powder neutron and synchrotron X‐ray diffraction revealed that this compound adopts the ideal cubic perovskite structure with O2?/H? disorder. Surprisingly, despite the non‐bonding nature between Cr 3d t2g orbitals and the H 1s orbital, it exhibits G‐type spin ordering at TN≈380 K, which is higher than that of RCrO3 (R=rare earth) and any chromium oxides. The enhanced TN in SrCrO2H with four Cr‐O‐Cr bonds in comparison with RCr3+O3 with six Cr‐O‐Cr bonds is reasonably explained by the tolerance factor. The present result offers an effective strategy to tune octahedral tilting in perovskites and to improve physical and chemical properties through mixed anion chemistry. 相似文献
168.
Dr. Yoji Horii Dr. Marko Damjanović Dr. M. R. Ajayakumar Prof. Dr. Keiichi Katoh Prof. Dr. Yasutaka Kitagawa Prof. Dr. Liviu Chibotaru Dr. Liviu Ungur Prof. Dr. Marta Mas-Torrent Prof. Dr. Wolfgang Wernsdorfer Prof. Dr. Brian K. Breedlove Prof. Dr. Markus Enders Prof. Dr. Jaume Veciana Prof. Dr. Masahiro Yamashita 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(39):8621-8630
Presented here is a comprehensive study of highly oxidized multiple-decker complexes composed of TbIII and CdII ions and two to five phthalocyaninato ligands, which are stabilized by electron-donating n-butoxy groups. From X-ray structural analyses, all the complexes become axially compressed upon ligand oxidation, resulting in bowl-shaped distortions of the ligands. In addition, unusual coexistence of square antiprism and square prism geometries around metal ions was observed in +4e charged species. From paramagnetic 1H NMR studies on the resulting series of triple, quadruple and quintuple-decker complexes, ligand oxidation leads to a decrease in the magnetic anisotropy, as predicted from theoretical calculations. Unusual paramagnetic shifts were observed in the spectra of the +2e charged quadruple and quintuple-decker complexes, indicating that those two species are actually unexpected triplet biradicals. Magnetic measurements revealed that the series of complexes show single-molecule magnet properties, which are controlled by the multi-step redox induced structural changes. 相似文献
169.
Osamu Takahashi Katsuyoshi Yamasaki Youji Kurihara Yoji Umezawa Motohiro Nishio 《Tetrahedron》2009,65(27):2157-2168
170.
Liquid-phase Reductive Deposition as Novel Preparation Method for Highly Dispersive Nickel Catalysts
Hideyuki Takahashi Yoji Sunagawa Sarantuya Myagmarjav Atsushi Muramatsu 《Catalysis Surveys from Asia》2005,9(3):187-192
We have been developing the selective deposition method onto TiO2 nanoparticles, named as the liquid-phase selective-deposition method, where TiO2 plays a role of formation center of Ni nanoparticles as well as protection from the aggregative growth of the particles.
The concept of this method is to well disperse and stabilize Ni nanoparticles on TiO2 surface by specific adsorption of Ni precursory complexes and then heterogeneous nucleation on the adsorption sites. The
particle size was decreased with increasing the amount of Zn added, thus the catalytically active Ni surface area was increased.
The selective deposition onto TiO2 surface and addition of Zn to the nanoparticle promoted the catalytic activity of Ni–Zn nanoparticle, e.g. the catalytic
activity of Ni–Zn/TiO2 was ca. 10 times higher than that of the unsupported Ni nanoparticles. Ni in the nanocomposite was assigned as metallic,
although their surface was oxidized under the atmospheric condition, but Zn and B were deposited as their oxide. 相似文献