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41.
An indium triiodide-catalyzed substitution of the acetoxy group in alkyl acetates with thiosilanes provides access to a variety of thioethers. The method is efficient for a wide scope of acetates such as primary alkyl, secondary alkyl, tertiary alkyl, allylic, benzylic, and propargylic acetates. 相似文献
42.
Ternary austenitic model alloys were modified with 0.25?wt.% titanium and irradiated in the Fast Flux Test Reactor (FFTF) at dose rates ranging over more than two orders in magnitude. While lowering of the dose rate strongly increases swelling by shortening the incubation dose, the steady-state swelling rate is not affected by dose rate. Although titanium addition strongly alters the void microstructure, swelling at about 420°C does not change with titanium additions, but the sensitivity to dose rate is preserved. 相似文献
43.
Reforming of dimethyl ether with carbon dioxide into synthesis gas has been carried out over a mixed catalyst containing Cu-based methanol decomposition catalyst and alumina. The catalyst is found to show a high activity and selectivity. Catalyst stability and deactivation mechanism was also examined. 相似文献
44.
Masayoshi Itoh Kenji Iwata Jun‐Ichi Ishikawa Hiroshi Sukawa Hideaki Kimura Koichi Okita 《Journal of polymer science. Part A, Polymer chemistry》2001,39(15):2658-2669
Nine new kinds of thermosetting polymers with the Si(H)? C?C unit were synthesized by dehydrogenative polycondensation reactions between hydrosilanes and diethynyl compounds in the presence of a magnesia catalyst. Phenylsilane, silane, vinylsilane, and n‐octylsilane were used as the hydrosilanes, and 1,3‐diethynylbenzene, 1,4‐diethynylbenzene, 4,4′‐diethynyldiphenyl ether, and 1,3‐diethynyl‐1,1,3,3‐tetramethyldisiloxane were used as the diethynyl compounds. All the polymers were thermosetting, highly heat‐resistant, easily soluble in a solvent, and moldable. In particular, ? Si(R)H? C?C? C6H4? C?C? (R = H or CH?CH2) showed high thermal stability; the temperature of 5% weight loss was greater than 800 °C, and the residue at 1000 °C was over 90%. The thermal stabilities of the polymers were attributed to the crosslinking reaction of the Si? H and C?C bonds. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2658–2669, 2001 相似文献
45.
Koichi Sakamaki Joji Ohshita Atsutaka Kunai Hidenobu Nakao Akira Adachi Koichi Okita 《应用有机金属化学》2001,15(7):604-612
We have synthesized novel σ–π conjugated polymers with an alternating organosilanylene and π‐electron system, intending to utilize them for hole‐transporting materials of electroluminescent (EL) devices. 3,6‐Di(lithioethynyl)carbazoles were co‐polymerized with organodichlorosilanes to give the corresponding polymers with molecular weights of MW = 2000–5000. Another type of polymer with a thienylene unit was also synthesized by the nickel‐catalyzed reaction of the di‐Grignard reagent of 1,2‐bis[2‐(5‐bromothienyl)]tetraethyldisilane with 3,6‐dibromocarbazole, the molecular weight being Mn = 3100. The EL devices with a double‐layer system composed of tris(8‐quinolinolato)aluminum(III) and the present polymers as the emitting‐electron‐transporting and hole‐transporting layers, respectively, emit green EL with a maximum intensity of the order of 103 cd m?2. Of these, the device with the thienylene–carbazole polymers exhibited the highest luminance of 1480 cd m?2. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
46.
47.
M. Tanemura T. Okita J. Tanaka H. Yamauchi L. Miao S. Tanemura R. Morishima 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2005,34(1-3):283-286
Glassy carbon plates, a Ni mesh coated with a carbon film and mechanically
polished graphite plates were Ar+ ion-bombarded with and without a
simultaneous Mo supply at room temperature. Conical protrusions were formed
on the sputtered surfaces, and in some cases carbon nanofibers (CNFs) 0.2–10 μm in length and 10–50 nm in diameter grew on the tips. The growth of CNF-tipped-cones was optimized in terms of the ion-incidence angle and the rate-ratio of sputtering and seeding. Oblique sputtering was proved to
be quite effective to grow the CNF-tipped-cones. Thus, the redeposited massive carbon atoms onto cones were thought to diffuse toward the cone tips, resulting in CNF formation. This growth mechanism was confirmed by transmission electron microscope (TEM) observation disclosing the
boundary-less structure between conical bases and CNFs. TEM observation of
CNF-tipped-cones also revealed no-hollow structure and an amorphous nature
of CNFs. Since this sputtering method is a room-temperature process and
quite straightforward, ion-induced CNFs promise to have myriad applications,
such as field emission sources for flat panel displays. 相似文献
48.
Shuji Fujisawa Yusuke Okita Tsuguyuki Saito Eiji Togawa Akira Isogai 《Cellulose (London, England)》2011,18(5):1191-1199
A method for conversion of carboxyl groups present on the surface of TEMPO-oxidized cellulose nanofibrils to N-acylureas using carbodiimide was developed. A TEMPO-oxidized cellulose nanofibril with free carboxyl groups (TOCN–COOH) dispersed
in N,N-dimethylformamide (DMF) is prepared from a bleached kraft pulp, and then the TOCN–COOH is reacted with either N,N′-diisopropylcarbodiimide (DIC) or N,N′-dicyclohexylcarbodiimide (DCC) under apparently homogeneous conditions. FT-IR and solid-state 13C NMR analyses showed that the reaction products contained N-acylurea groups, and yields were >80%. Conversion ratios of carboxyl groups to N-acylureas are approximately 80 and 60%, when DIC and DCC, respectively, of 5 mol per mole of carboxyl groups are used as
the reagents. X-ray diffraction analysis demonstrated that neither crystallinity nor crystal width of the original wood cellulose
I structure was changed by the N-acylurea formation. The isolated and never-dried TOCN-N-acylureas are nano-dispersed in DMF but not in i-PrOH or dioxane. Pellets of the TOCN-N-acylureas had water-contact angles of >70°. 相似文献
49.
Solution of N-S equations based on the quadtree cut cell method 总被引:1,自引:0,他引:1
With the characteristic of the quadtree data structure, a new mesh generation method, which adopts square meshes to decompose
a background domain and a cut cell approach to express arbitrary boundaries, is proposed to keep the grids generated with
a good orthogonality easily. The solution of N-S equations via finite volume method for this kind of unstructured meshes is
derived. The mesh generator and N-S solver are implemented to study two benchmark cases, i.e. a lid driven flow within an
inclined square and a natural convection heat transfer flow in a square duct with an inner hot circular face. The simulation
results are in agreement with the benchmark values, verifying that the present methodology is valid and will be a strong tool
for two-dimensional flow and heat transfer simulations, especially in the case of complex boundaries.
Supported by Japan Society for the Promotion of Science (Grant No. C20560175) and the National Natural Science Foundation
of China (Grant Nos. 10872159 and 40675011) 相似文献
50.
Methyl (R)-o-chloromandelate ((R)-), which is an intermediate for a platelet aggregation inhibitor named clopidogrel, was obtained in >99% ee by the asymmetric reduction of methyl o-chlorobenzoylformate (2) (up to 1.0 M) with recombinant E. coli overproducing a versatile carbonyl reductase. 相似文献