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991.
A two-dimensional numerical simulation of natural convection in a rectangular enclosure heated from below and cooled from
above has been conducted with non-Newtonian phase-change-material (PCM) microcapsulate slurry with latent heat capacities.
The formulation of the mathematical model in dimensionless co-ordinates and discretization of the governing equations have
been done using the finite volume method. Both natural convection and heat transfer characteristics are discussed about natural
convection with PCM microcapsulate slurry, which exhibits the pseudoplastic non-Newtonian fluid behavior and a peak value
in the specific heat capacity with latent heat. The viscosity of the present PCM microcapsulate slurry is assumed to follow
the Ostwald-de Waele power law fluid model with the power-law index n and the consistency coefficient K. The effects of phase-change material, the mass concentration, and the aspect ratio Ar on the natural convection heat transfer
are described, respectively. By comparing with the results of microcapsule slurry without phase change, the enhancement in
heat transfer is found in microcapsule slurry with phase change during the phase change temperature range. Numerical simulations
are performed in the following parametric ranges: the width–height aspect ratio of the enclosure Ar from 2 to 20, the mass
concentrations C
m of the slurry from 10 to 40%, power law index n of the slurry from 0.89 to 1.0 and Rayleigh numbers Ra ranges from 103 to 107. 相似文献
992.
Ichihara Mai Inoue Kazumasa Fukushi Masahiro Shimizu Hideo Tsuruoka Hiroshi Veerasamy Nimelan Tsukada Mizuho Soyama Sho Hosokawa Shota Kato Tatsuki Sagara Hiroaki Taguchi Yoshiaki Natarajan Thennaarassan 《Journal of Radioanalytical and Nuclear Chemistry》2021,329(1):427-435
Journal of Radioanalytical and Nuclear Chemistry - Tokatsu area was on one pathway of the radioactive plumes released in the Fukushima Daiichi Nuclear Power Plant accident and absorbed dose rate in... 相似文献
993.
Dr. Kunihiko Okano Dr. Satoshi Aya Dr. Fumito Araoka Haruki Obara Shiori Sato Prof. Dr. Takashi Yamashita Prof. Dr. Hideo Takezoe Prof. Dr. Kouichi Asakura 《Chemphyschem》2015,16(1):95-98
A periodic stripe pattern is found in the nematic phase close to the smectic phase of photoresponsive achiral liquid‐crystalline compounds. The origin of the stripe patterns can be ascribed to an extremely large bent elastic constant K33. In addition, we succeeded in controlling the pattern by the following two methods: 1) the stripe disappears by a trans–cis photoisomerization upon UV light irradiation and reappears upon light termination, and 2) the stripe pattern is stabilized over the whole nematic phase, at approximately 10 °C, by polymerization of the compounds. 相似文献
994.
Takasaki M Motoyama Y Yoon SH Mochida I Nagashima H 《The Journal of organic chemistry》2007,72(26):10291-10293
Use of Ru/CNF-P, nanoruthenium particles dispersed on a nanocarbon fiber support, realizes highly efficient catalytic partial hydrogenation of 1,1'-bi-2-naphthol and -naphthyl-amine derivatives. The reactions proceed in high turnover numbers without racemization of the axial chirality, offering a practical procedure for the production of optically pure 5,5',6,6',7,7',8,8'-octahydro-1,1'-binaphthyls in good to high yields. 相似文献
995.
An intramolecular Friedel-Crafts reaction of N-methoxymethyl sulfoneamides 3e-j containing an acetylene dicobalt moiety was found to proceed smoothly to afford eight- and nine-membered cyclic amines 4e-j in high yields. 相似文献
996.
997.
Akisada H Kuwahara J Koga A Motoyama H Kaneda H 《Journal of colloid and interface science》2007,315(2):678-684
The critical micelle concentrations (CMC) of binary mixtures of alkyltrimethylammonium bromides (CnTAB) were measured by a conductivity method. The CMCs of C12TAB-C14TAB and C14TAB-C16TAB systems exhibit the usual behavior, namely a monotonic decrease of the CMC with the mole fraction of the longer chain surfactant. However, the CMC behaviors of C10TAB-C16TAB, C11TAB-C16TAB, C12TAB-C16TAB, and C11TAB-C14TAB are unusual. The behaviors of the CMCs with mole fraction for these systems consist of three regions, of which the first is characterized by a very small decrease of the CMC in the range of low mole fraction, followed by a second where there is an abrupt decrease of the CMC, and a third where the CMCs exhibit their usual behavior. The molecular interaction parameter omega is almost equal to zero for mixtures that have the usual CMC behavior, but is small and positive for those systems with unusual CMCs. We infer that for very low mole fractions of C16TAB, the C16TA ion in the C12TAB-C16TAB system penetrates imperfectly into the micelle and its two methylene groups exist outside the micelle. 相似文献
998.
999.
Normally disfavored 5-endo-trig cyclizations proceed in N-homoallylsulfonamides bearing a CF(3), CCl(3), CO(2)Et or CN group at the C-3 position, via an intramolecular S(N)2'-type or addition reaction to construct pyrrolidine rings, even though the system allows a more favorable 5-exo-trig pathway. 相似文献
1000.
Benten H Guo J Ohkita H Ito S Yamamoto M Sakumoto N Hori K Tohda Y Tani K 《The journal of physical chemistry. B》2007,111(37):10905-10914
Intermoiety electronic interactions in the singlet and triplet excimer states of triply bridged [3.3.n](3,6,9)carbazolophanes ([3.3.n]Cz, n=3-6) were studied by emission and transient absorption measurements. In these [3.3.n]Cz molecules, the dihedral angle and the separation distance r between fully overlapped two carbazole rings change systematically from nearly parallel (n=3, r=3.35 A) to oblique (n=6, r=4.03 A). In rigid glass at 77 K, [3.3.n]Cz (n=3, 4) (r<4 A) exhibited red-shifted and structureless excimer fluorescence and phosphorescence while [3.3.n]Cz (n=5, 6) (r>4 A) exhibited monomer-like vibrational fluorescence and phosphorescence. In solution at 130 K, all [3.3.n]Cz molecules exhibited an excimeric fluorescence band while [3.3.5]Cz still exhibited monomer-like phosphorescence. Transient absorption spectra measured at 294 K exhibited local excitation and charge-transfer bands for all [3.3.n]Cz molecules in the excited singlet and triplet states, suggesting that not only singlet but also triplet excimers of carbazole are formed at room temperature. Furthermore, the singlet-triplet energy gap decreased with the decrease in n, suggesting that electrons are effectively delocalized over the two carbazole moieties. These findings showed that both singlet and triplet excimers of carbazole are formed with a separation distance shorter than about 4 A and are most stable in the parallel-sandwich structure and that the configurational mixing between exciton resonance and charge resonance states plays an essential role in the formation of singlet and triplet excimers of carbazole. 相似文献