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101.
Toshikazu Kaise Hiroshi Yamauchi Yoshiya Horiguchi Takayuki Tani Shigenobu Watanabe Teruhisa Hirayama Shozo Fukui 《应用有机金属化学》1989,3(3):273-277
The acute toxicity of methylarsonic acid, CH3AsO(OH)2 (MAA), dimethylarsininc acid, (CH3)2AsO(OH) (DMAA), and trimethylarsine oxide, (CH3)3AsO (TMAO), were examined in mice with oral administration. The LD50 values of MAA, DMAA and TMAO were 1.8, 1.2 and 10.6 g kg?1 respectively. The toxicity of MAA and DMAA was very much lower than that for inorganic arsenic compounds. It was shown that TMAO has a similar acute toxicity to arsenobetaine. On the other hand, when the mice were administered 14.4 g kg?1 of TMAO once only orally, a garlic-like odor (trimethylarsine, (CH3)3As) was definitely detectable in the exhalation of the animals by the human olfactory sense within about a few minutes. 相似文献
102.
W. Heiss E. Kaufmann M. Bberl T. Schwarzl G. Springholz G. Hesser F. Schffler K. Koike H. Harada M. Yano R. Leitsmann L.E. Ramos F. Bechstedt 《Physica E: Low-dimensional Systems and Nanostructures》2006,35(2):241
Lattice-type mismatched heteroepitaxy is demonstrated as a novel concept for the fabrication of almost ideal, highly luminescent nanocrystal quantum dots that are coherently embedded in a single-crystalline matrix. In this approach, the formation of quantum dots is induced by transformation of a metastable epitaxial 2D quantum well into an array of isolated nanocrystals with-highly symmetric shape. This process is driven by the lattice-type mismatch between the constituent materials and the resulting miscibility gap. The investigated PbTe/CdTe heterosystem has a model character because it combines two compounds with different cubic lattice types but almost identical lattice constants. The obtained epitaxial nanocrystals exhibit outstanding properties such as a well-defined symmetric shape, the absence of strain, intermixing and a wetting layer, which is in contrast to the conventional Stranski–Krastanow quantum dots. The small-rhomboedric-cubo-octahedron PbTe/CdTe nanocrystals on GaAs substrates display intense room temperature mid-infrared luminescence as is crucial for device applications. Ab initio density functional theory is used to clarify the interface structure, indicating that the covalent and ionic bonding character of CdTe and PbTe is maintained across the interface. 相似文献
103.
Daisuke Sasaki Yoshihiro Suzuki Hagiwara Toshiki Shoichiro Yano Takashi Sawaguchi 《Journal of Analytical and Applied Pyrolysis》2007,80(2):312-318
The reactive end groups of nonvolatile oligomers obtained by controlled thermal degradation of poly(propylene-ran-ethylene) and poly(propylene-ran-1-butene) were determined by 1H and 13C NMR spectroscopy. The molar ratio of unsaturated to saturated end groups was found to be about 9:1. The average number of unsaturated end groups per molecule was between 1.6 and 1.8, indicating that 60–80 mol% of the oligomer molecules were telechelic, having two terminal unsaturated end groups. These oligomers had a lower polydispersity than the raw material, despite their lower molecular weight and melting temperature. Although the end groups resulting from each monomer unit could be detected by 13C NMR, the end group composition differed from that of the main chains of the raw materials. The end group composition was satisfactorily explained by the differences in bond dissociation energy and activation energy of elementary reactions that occurred during thermal degradation, based on the monomer composition of the raw materials. 相似文献
104.
S. Iwamoto A.N. Nakagaito H. Yano M. Nogi 《Applied Physics A: Materials Science & Processing》2005,81(6):1109-1112
The fibrillation of pulp fiber was attempted by two methods, a high-pressure homogenizer treatment and a grinder treatment. The grinder treatment resulted in the successful fibrillation of wood pulp fibers into nanofibers. The nanofibers demonstrate promising characteristics as reinforcement material for optically transparent composites. Due to the size effect, the nanofiber-reinforced composite retains the transparency of the matrix resin even at high fiber content such as 70 wt %. Since the nanofiber is an aggregate of semi-crystalline extended cellulose chains, its addition also contributes to a significant improvement in the thermal expansion properties of plastics while maintaining its ease of bending. Cellulose nanofibers have tremendous potential as a future resource since they are produced in a sustainable manner by plants, one of the most abundant organic resources on earth. PACS 81.05.Lg; 81.05.Qk 相似文献
105.
Toughness enhancement of cellulose nanocomposites by alkali treatment of the reinforcing cellulose nanofibers 总被引:1,自引:0,他引:1
Nanocomposites were produced with NaOH aqueous solution-treated microfibrillated cellulose (MFC) and phenolic resin, and the
mechanical properties were compared with their microcomposite counterparts based on pulp fiber. Tensile tests showed that
strong alkali-treated MFC nanocomposites with resin content around 20 wt.% achieved strain at fracture values two times higher
than those of untreated MFC nanocomposites and five times higher than those of untreated pulp microcomposites. The improvement
in work of fracture of alkali-treated MFC nanocomposites was attributed to the ductility of the nanofibers caused by transformations
in the amorphous regions along the cellulose microfibrils. 相似文献
106.
K. Yano 《Physics letters. A》1973,46(3):223-224
A consistent theory of thermo-luminescent process is developed, following Johnson's classical explanation. The situation before the thermal excitation is explained. Expressions for the transition rate and the frequency factor are led out. 相似文献
107.
108.
Takefumi Yano Shigeru Ikai Katsutoshi Washio 《Journal of polymer science. Part A, Polymer chemistry》1985,23(12):3069-3080
The catalyst system comprised of a heptane solution of magnesiumoctoate-H2O-Tetrabutoxytitanium/diethylaluminumchloride was highly active for ethylene polymerization at a high temperature. High productivity for the catalyst system at a low temperature was achieved by the aging of the catalyst components. The effect of different orders of addition of the catalyst components on productivity was investigated to assume the role of each components in the formation of active species. 相似文献
109.
Okimichi Yano Susumu Saito Yoshio Sato Toshifumi Takeda Atsushi Tanaka Yasaku Wada 《Journal of Polymer Science.Polymer Physics》1981,19(2):221-227
The dielectric loss of high-density polyethylene was measured from 1 kHz to 100 MHz with the improved calorimetric method at liquid-helium temperature for samples with different oxidation times t. Two loss peaks, centered at ca. 4 kHz and at 1 MHz, both increase in height with increasing t. On the bases of these results along with previously reported ones, the low-frequency and high-frequency losses are ascribed to the tunneling of protons of OH groups in crystalline and amorphous regions, respectively. 相似文献
110.
Izhar H. Qureshi Shaheen A. Husain Radia Noorani Najma Murtaza Yoichi Iitaka Shigeo Iwasaki Shigenobu Okuda 《Tetrahedron letters》1980,21(20):1961-1962
The complete structure of a unique tricyclic sesterterpene, stellatic acid, was established by X-ray diffraction of its p-bromophenacyl ester. 相似文献