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991.
Application of a new azo‐polymer as a photo‐alignment material for liquid crystals (LCs) was demonstrated. 4‐(Vinyloxyethyloxy)azobenzene (VAZO), which has thermally reactive vinyl ether groups, reacted with the ? OH groups of poly(4‐hydroxystyrene) (PHS) during the baking process. The azo‐attached polymer (PHS‐VAZO) film showed anisotropic spectra after exposure to 365‐nm linear polarized light (LPL) unlike the VAZO‐doped poly(methylmethacrylate) (PMMA) film. The anisotropy of the film was small at high concentration of the azo‐chromophore because of thermal randomization of the polarized state. In the evaluation of photo‐alignment of the LC, the LC hybrid cell using the PHS‐VAZO film achieved high LC alignment. The azo‐attached polymer using the thermal reaction of vinyl ethers is useful for a photo‐alignment material. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
992.
Shigeru Mase 《Annals of the Institute of Statistical Mathematics》1996,48(2):201-213
The threshold method estimates the total rainfall F
G in a region G using the area B
G of the subregion where rainfall intensity exceeds a certain threshold value c. We model the rainfall in a region by a marked spatial point process and derive a correlation formula between F
G and B
G. This correlation depends not only on the rainfall distribution but also on the variation of number of raining sites, showing the importance of taking account of the spatial character of rainfall. In the extreme case where the variation of number of raining sites is dominant, the threshold method may work regardless of rainfall distributions and even regardless of threshold values. We use the lattice gas model from statistical physics to model raining sites and show a huge variation in the number of raining sites is theoretically possible if a phase transition occurs, that is, physically different states coexist. Also, we show by radar observation datasets that there are huge variations of raining sites actually. 相似文献
993.
994.
Photo-modulation voltammetry was applied to detecting the photolysis of tetraphenylborate (TPhB) at a water/1,2-dichloroethane (DCE) interface by using a He-Cd laser emitting a beam with a major 325-nm line and minor lines of shorter wavelengths. When the interface was irradiated from the water-phase side, a new wave appeared in the photomodulation voltammogram, suggesting that TPhB was photolyzed and the anionic product was transferred across the interface. The concentration dependence of the photocurrents was successfully explained by a theory based on the photolytic process at the interface. 相似文献
995.
Nickel complex catalysts, Ni(cod)2-2PPh3 and Ni(cod)2-dppb systems in particular, catalyze the addition reactions of phenyl allyl selenide to terminal alkynes to regioselectively afford 2-phenylseleno-1-allyl-1-alkenes in good to excellent yields. A mechanism that involves a η3-allyl-nickel complex is proposed on the basis of isolation, crystal structure determination and reactivity study of the complex. 相似文献
996.
N.S. Buenconsejo Jr. Tetsu Fujii Shigeru Koyama 《Experimental Thermal and Fluid Science》1990,3(6):603-612
Buoyancy-induced airflow in a box with one wall heated, an unheated inlet duct connected to its floor, and an exit duct with one side heated connected to its ceiling is experimentally investigated. A flow rate prediction method based on buoyancy and flow resistance balance is proposed and experimentally validated. The flow pattern and thermal stratification in the box; the flow resistance characteristics for low Reynolds numbers; the relationship among buoyancy, flow resistance, and pressure defect; the chimney effect caused by the exit duct; and the heat transfer characteristics of the heated walls are clarified. The flow rate, thermal stratification, and flow enhancement due to the chimney effect are considerably dependent on the size of the gap of the exit duct. 相似文献
997.
Local heat transfer and pressure drop measurements were made during condensation of a zeotropic CFC114-CFCll3 refrigerant mixture in the annulus of a double-tube coil consisting of three U-bends and four straight lengths. The inner tube is a 19.1-mm O.D. corrugated copper tube with wire fins soldered onto the outer surface and the inner diameter of the outer duct is 25.0 mm. The vapor-phase mass transfer coefficient exhibited a sawtooth behavior with the U-bends showing higher coefficients than the straight lengths. The frictional pressure gradient data agreed well with a previously developed empirical equation for the condensation of pure refrigerants. A prediction method for the condensation heat transfer rate was proposed on the basis of the correlations of the vapor-phase mass transfer coefficient and heat transfer coefficient of the condensate film. The heat transfer data were correlated by the present method to a mean absolute deviation of 12.9%. 相似文献
998.
This paper deals with steady-state response of a continuous system with nonlinear boundary conditions which are motion-limiting constraint. An analytical method of approximate solution for the continuous system with unsymmetrical collision characteristics in which the beam end collides with a stop once in one period of its vibration is presented. Some numerical results of the approximate solution are shown. Contrary to the case of continuous system with symmetrical collision characteristics, the resonance curves of nonlinear response of approximate solution are shown as discontinuous line. Some numerical results of a continuous system with no hysteresis damping are compared with those of a continuous system with hysteresis damping and a single-degree-of-freedom system. 相似文献
999.
Dr. Takahiro Tsuchiya M. Sc. Marc Rudolf Dr. Silke Wolfrum Dr. Shankara Gayathri Radhakrishnan Ryo Aoyama Yuya Yokosawa Azusa Oshima Prof. Dr. Takeshi Akasaka Prof. Dr. Shigeru Nagase Prof. Dr. Dirk M. Guldi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(2):558-565
For the first time, a C60 derivative ( 1 ) and two different lanthanum metallofullerene derivatives, La@C82Py ( 2 ) and La2@C80Py ( 3 ), that feature a pyridyl group as a coordination site for transition‐metal ions have been synthesized and integrated as electron acceptors into coordinative electron‐donor/electron‐acceptor hybrids. Zinc tetraphenylporphyrin ( ZnP ) served as an excited‐state electron donor in this respect. Our investigations, by means of steady‐state and time‐resolved photophysical techniques found that electron transfer governs the excited‐state deactivation in all of these systems, namely 1/ZnP , 2/ZnP , and 3/ZnP , whereas, in the ground state, notable electronic interactions are lacking. Variation of the electron‐accepting fullerene or metallofullerene moieties provides the incentive for fine‐tuning the binding constants, the charge‐separation kinetics, and the charge‐recombination kinetics. To this end, the binding constants, which ranged from log Kassoc=3.94–4.38, are dominated by axial coordination, with minor contributions from the orbital overlap of the curved and planar π systems. The charge‐separation and charge‐recombination kinetics, which are in the order of 1010 and 108 s?1, relate to the reduction potential of the fullerene and metallofullerenes, respectively. 相似文献
1000.
Dr. Mitsuaki Suzuki Dr. Naomi Mizorogi Tao Yang Prof. Dr. Filip Uhlik Prof. Dr. Zdenek Slanina Prof. Dr. Xiang Zhao Prof. Dr. Michio Yamada Prof. Dr. Yutaka Maeda Prof. Dr. Tadashi Hasegawa Prof. Dr. Shigeru Nagase Prof. Dr. Xing Lu Prof. Dr. Takeshi Akasaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(50):17125-17130
Although all the pure‐carbon fullerene isomers above C60 reported to date comply with the isolated pentagon rule (IPR), non‐IPR structures, which are expected to have different properties from those of IPR species, are obtainable either by exohedral modification or by endohedral atom doping. This report describes the isolation and characterization of a new endohedral metallofullerene (EMF), La2@C76, which has a non‐IPR fullerene cage. The X‐ray crystallographic result for the La2@C76/[NiII(OEP)] (OEP=octaethylporphyrin) cocrystal unambiguously elucidated the Cs(17 490)‐C76 cage structure, which contains two adjacent pentagon pairs. Surprisingly, multiple metal sites were distinguished from the X‐ray data, which implies dynamic behavior for the two La3+ cations inside the cage. This dynamic behavior was also corroborated by variable‐temperature 139 La NMR spectroscopy. This phenomenon conflicts with the widely accepted idea that the metal cations in non‐IPR EMFs invariably coordinate strongly with the negatively charged fused‐pentagon carbons, thereby providing new insights into modern coordination chemistry. Furthermore, our electrochemical and computational studies reveal that La2@Cs(17 490)‐C76 has a larger HOMO–LUMO gap than other dilanthanum‐EMFs with IPR cage structures, such as La2@D3h(5)‐C78 and La2@Ih(7)‐C80, which implies that IPR is no longer a strict rule for EMFs. 相似文献