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171.
Thao Thi Phuong Nguyen Rie Tanabe Yoshiro Ito 《Applied Physics A: Materials Science & Processing》2014,116(3):1109-1117
The effects of an absorptive coating on the dynamics of underwater laser-induced shock process have been observed from the end of laser pulse to hundreds of microseconds after irradiation by time-resolved imaging techniques. A laser pulse of 13 ns at 1,064 nm was focused by a 40-mm focal length lens onto the surface of epoxy-resin blocks immersed in water to induce the shock process in the confining regime. A custom-designed time-resolved photoelasticity imaging technique and a high-speed laser stroboscopic videography technique in photoelasticity mode were used to analyze the evolution of shock waves in the water phase, the strength of stress waves in the solid phase, the oscillation of cavitation bubbles, and the generation of bubble-collapse-induced shock waves. We showed that black paint coating enhances the strength of laser-induced stress wave inside the solid, drives faster shock waves traveling in the water phase, and produces higher-energy cavitation bubbles. We propose that even at power densities of 1 GW/cm2 and above, an absorptive coating can intensify the shock process by enhancing the absorption of laser energy by plasma. 相似文献
172.
Hexaorganosilylgermane (2) reacted with aldehydes and ketones (1) in the presence of catalytic amounts of fluoride ion in THF or HMPA to give 1-(triorgano-germyl)alkyl alcohols (3). 相似文献
173.
Eietsu Hasegawa Emi Tosaka Akira Yoneoka Yukinobu Tamura Shin-ya Takizawa Masaaki Tomura Yoshiro Yamashita 《Research on Chemical Intermediates》2013,39(1):247-267
Photoinduced electron-transfer reaction of α-bromomethyl-substituted benzocyclic β-keto esters with tertiary amines was investigated. Debrominated β-keto esters and ring-expanded γ-keto esters were obtained as major products. On the basis of mechanistic experiments it was concluded that these products are formed via a reaction sequence of selective carbon–bromine bond cleavage and subsequent competitive hydrogen abstraction and Dowd–Beckwith ring-expansion of the resulting primary alkyl radicals. The characteristic product distribution observed for the type of amine used is rationalized on the basis of selective reaction pathways of generated radical intermediates that depend on the nature of the amine radical cations. 相似文献
174.
The immobilization of Br4MoO? in both poly-p-vinyipyridine with a flexible backbone and silica as a rigid polymer support was carried out. The oxidation of alcohols by t-butyl hydroperoxide (t-BuOOH) was then studied in the presence of the polymer-supported complexes obtained. The differences of the reactivity between catalysts supported by organic and inorganic polymers are discussed. The best carrier for Br4MoO? as an oxidation catalyst is a silica modified with silane coupling reagent (dimethyloctadecyl-[3-(trimethoxysilyl)propyl] ammonium chloride). 相似文献
175.
176.
Dietmar Schomburg Yoshiro Kobayashi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):17-19
Abstract The results of an X-ray structure analysis show the strain which the cage system imposes on the bond parameters. Mean values of bond lengths are P[sbnd]Csp3 1.872 Å and P[sbnd]Csp2 1.840 Å. 相似文献
177.
We realize simultaneous quantum degeneracy in mixtures consisting of the alkali and alkaline-earth-like atoms Li and Yb. This is accomplished within an optical trap by sympathetic cooling of the fermionic isotope ?Li with evaporatively cooled bosonic 1??Yb and, separately, fermionic 1?3Yb. Using cross-thermalization studies, we also measure the elastic s-wave scattering lengths of both Li-Yb combinations, |a(?Li-1??Yb)| = 1.0 ± 0.2 nm and |a(?Li-1?3Yb)| = 0.9 ± 0.2 nm. The equality of these lengths is found to be consistent with mass-scaling analysis. The quantum degenerate mixtures of Li and Yb, as realized here, can be the basis for creation of ultracold molecules with electron spin degrees of freedom, studies of novel Efimov trimers, and impurity probes of superfluid systems. 相似文献
178.
We investigate low-frequency electron spin dynamics in a quantum Hall system with wire confinement by nuclear spin relaxation measurements. We developed a technique to measure the local nuclear spin relaxation rate T(1)(-1). T(1)(-1) is enhanced on both sides of the local filling factor ν(wire)=1, reflecting low-frequency fluctuations of electron spins associated with Skyrmions inside the wire. As the wire width is decreased, the fast nuclear spin relaxation is suppressed in a certain range of Skyrmion density. This suggests that the multi-Skyrmion state is modified and the low-frequency spin fluctuations are suppressed by the wire confinement. 相似文献
179.
With cat. PdCl2(PhCN)2 and SnCl2, 4-pentene-1,3-diol caused regioselective carbonyl allylation at 3-position in DMF to produce 2-substituted 3-vinyltetrahydrofurans and/or 1-substituted 2-vinylbutane-1,4-diols, and cyclic carbonate of 4-pentene-1,3-diol caused regioselective carbonyl allylation at terminal 5-position in THF to produce 1-substituted 3-hexene-1,6-diols. 相似文献
180.
Kikuo Komori Kenji Murai Shotaro Miyajima Takao Fujii Shino Mohri Yoshiro Ono Yasuyuki Sakai 《Analytical sciences》2008,24(8):957-962
To simply evaluate toxicity for various types of exhaust-gas samples collected in various locations, we developed a small-scale (150 mL) batch-type completely closed gas exposure device incorporated with an air-liquid interface culture of a human alveolar epithelial cell line, A549. On the basis of cell viability tests using an acid phosphatase assay after 48 h of gas exposure, the developed device was able to measure clear dose-response relationships for volatile organic and inorganic compounds, such as benzene, trichloroethylene (TCE), acetone, SO(2) and NO(2) gases, but not CO gas. Although the 50% effective concentration values in the device were much higher than 50% lethal concentration values reported in animal experiments, the tendency of the toxic intensity observed in the former was roughly consistent with that of the acute toxicity in the latter. We further applied the device to evaluate the toxicity of cigarette smoke as an example of actual environmental gases, and successfully measured acute cell death from the gas after 48 h of exposure. The present small device is expected to be one of good tools not only in simultaneously assessing various gaseous chemicals or samples, but also in studying acute toxicity expression mechanisms in human lung epithelia. 相似文献