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91.
Mixtures of styrene and n-butyl acrylate of various compositions were grafted onto cellulose and cellulose triacetate fibers preirradiated with γ-rays at 0°C in air. Monomer reactivity ratios of the grafted copolymers were found to be different from those of the nongrafted copolymers or those of AIBN-initiated copolymers. The active species initiating the graft copolymerization were trapped radicals for cellulose and peroxides for cellulose triacetate. Kinetic investigations of the graft copolymerization of styrene onto preirradiated cellulose triacetate fibers were also carried out, and it was found that the kinetic scheme for radical polymerization is also applicable to graft copolymerization in a heterogeneous system. 相似文献
92.
Shigenobu Kobayashi Tomiji Wakida Shouhua Niu Satoshi Hazama Taisuke Ito Yoshiyuki Sasaki 《Coloration Technology》1995,111(3):72-76
Three kinds of aramid fabrics, Technora (modified p-aramid), Conex (m-aramid) and Kevlar (p-aramid), were subjected to sputter etching and argon low-temperature plasma treatments after dyeing in black with disperse dyes. The depth of shade increased considerably on Technora and Kevlar with the sputter etching treatment, but not on Conex fabrics. Argon low-temperature plasma treatment had virtually no effect on the depth of shade on the aramid fabrics. 相似文献
93.
The local disturbances ahead of a running crack front in a viscoelastic solid were measured through noncontact electro-optical tools. It was observed that the very high local strain rate up to 200/sec exists even in the present quasistatic loading case. It may be concluded that the running crack propagation velocities, not the conventional average strain rates ranging from about 10?4/sec to 10?2/sec, govern the local disturbances, as the crack propagation velocities always exceed 200m/sec for both average strain rates, while the local strain rates observed do not show much differences between both average strain rate cases. 相似文献
94.
Tsuyoshi Hagio Kazuo Kobayashi Hisayoshi Yoshida Hiroaki Yasunaga Hiroshi Nishikawa 《Journal of the American Ceramic Society》1989,72(8):1482-1484
Pressureless sintering of hexagonal boron nitride (BN) was performed using a powder activated by mechano-chemical treatments. Physical properties of the sintered BN bodies depend on the type of starting powder and the conditions of the treatments. The BN body, which was obtained at 2000°C using an appropriate activated powder, was 99 wt% pure and was excellent in mechanical and physical properties, in spite of its low density (1.64 g/cm3 ). 相似文献
95.
Toshiaki Enoki Yousuke Kobayashi Chika Katsuyama Vladimir Yu. Osipov Marina V. Baidakova Kazuyuki Takai Ken-ichi Fukui Alexander Ya. Vul'' 《Diamond and Related Materials》2007,16(12):2029-2034
The structure, electronic and magnetic properties of nanodiamond and nanographite/nanographene are investigated. Detonation nanodiamond particles that are covered with amorphous graphitic composites are hydrothermally treated to remove the graphitic surface composites and to terminate the surface carbon atoms with hydrogen. The number of localized spins of dangling bonds and the hydrogen concentration increase upon the increase in the hydrothermal treatment time up to 40 h. Above 40 h, both drop discontinuously, a surface structural reconstruction was suggested. The creation of dangling bonds and an incomplete hydrogenation of the surface carbon atoms destabilize the surface, resulting in the structural reconstruction. Nanodiamond particles are thermally converted to nanographite/nanographene. A single nanographene sheet is successfully prepared by heat-treating nanodiamond particles. The edge of graphene sheet with its edge carbon atoms being hydrogen-terminated is investigated by UHV-STM/STS. Zigzag edges are found to have non-bonding π-state of edge origin, in good agreement with theoretical prediction. 相似文献
96.
Hidehiko Kobayashi Kenichi Shimosaka Miki Saitoh Takashi Mitamura 《Journal of the American Ceramic Society》1993,76(9):2389-2392
We investigated the conditions for low-temperature synthesis of ZrC fine powder from ZrO2 –Mg–CH4 . The synthesis utilizes a thermite-type reaction, with Mg as the reducing agent, and a reaction between Mg and CH4 gas as a carbon source. The Mg/ZrO2 molar ratio as well as the heating rate were varied. Because C can be continuously fed into the reaction group by the cyclic reaction of Mg through the formation and decomposition of Mg2 C3 (2Mg + 3CH4 → Mg2 C3 + 6H2 → 2Mg + 3C), a molar ratio of 2.2 for Mg/ZrO2 was sufficient for the synthesis of single-phase ZrC. ZrC powders were synthesized under the following conditions: Mg/ZrO2 molar ratio = 2.2, heating rate = 20°C/min, and temperature maintained at 750°C for 30 min. The amount of reaction heat produced in the reduction reaction of ZrO2 by Mg depended on the Mg/ZrO2 molar ratio, specifically, the amount of ZrO2 contained. Moreover, the cyclic reaction of Mg-Mg2 C3 –Mg was influenced by the amount of reaction heat described above and by the heating rate. The ZrC fine powder showed little aggregation and high dispersibility. 相似文献
97.
Lida T Nakamori R Yabuta R Yada S Takagi Y Mano N Ikegawa S Goto J Nambara T 《Lipids》2002,37(1):101-110
A facile and efficient synthesis of the carboxyl-linked glucosides of bile acids is described. Direct esterification of unprotected
bile acids with 2,3,4,6-tetra-O-benzyl-d-glucopyranose in pyridine in the presence of 2-chloro-1,3,5-trinitrobenzene as a coupling agent afforded a mixture of the
α- and β-anomers (ca. 1∶3) of the 1-O-acyl-d-glucoside benzyl ethers of bile acids, which was separated effectively on a C18 reversedphase chromatography column (isolated yields of α- and β-anomers are 4–9% and 12–19%, respectively). Subsequent hydrogenolysis
of the α- and β-acyl glucoside benzyl ethers on a 10% Pd−C catalyst in acetic acid/methanol/EtOAc (1∶2∶2, by vol) at 35°C
under atmospheric pressure gave the corresponding free esters in good yields (79–89%). Chemical specificities such as facile
hydrolysis and transesterification of the acyl glucosides in various solvents were also discussed. 相似文献
98.
The effect of the reaction kinetics on the ionic conductivity for a comblike‐type polyether (MEO) electrolyte with lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) was characterized by DSC, complex impedance measurements, and 1H pulse NMR spectroscopy. The ionic conductivity of these electrolytes was affected by the reaction condition of the methacrylate monomer and revealed by the glass transition temperature (Tg), spin–spin relaxation time (T2), steric effects of the terminal groups, and the number of charge carriers indicated by the VTF kinetic parameter. In this system, the electrolytes prepared by the reaction heating rate of 10°C/min of MEO–H and 15°C/min of MEO–CH3 showed maximum ionic conductivity, σi, two to three times higher in magnitude than that of the σi of the others at room temperature. As experimental results, the reaction kinetic rate affected the degree of conversion, the ionic conductivity, and the relaxation behaviors of polyether electrolytes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2149–2156, 2003 相似文献
99.
Summary This paper describes the so-called No Catalyst Copolymerization between dioxo-1,1-thiazetidine-1,2(Ethanesultam; ESm) and 2-methyl-2-oxazoline. The copolymerization took place without any added initiator to produce copolymers of MeOZO and ESm. The structure of the copolymer was determined by the IR and NMR spectra, elemental analysis, as well as by the result of an alkaline hydrolysis of the copolymer. The reaction scheme of the copolymerization via zwitterion mechanism (Eq 3–5) was proposed. 相似文献
100.
Keiji Kobayashi 《Journal of the American Ceramic Society》1990,73(11):3500-3502
F− - and OH− -free ZnO-B2 O3 -SiO2 -Al2 O3 -P2 O5 glasses used for semiconductor-device passivation or insulation are investigated with regard to compositional dependencies for thermal expansion, viscosity points, and metal oxide semiconductor (MOS) capacitor properties. The experimental data show that thermal expansion increases, and flow points decrease, when P2 O5 is substituted for B2 O3 . MOS capacitors passivated by OH− - and F− -free ZnO-based glasses exhibit normal capacitance-voltage curves. 相似文献