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排序方式: 共有621条查询结果,搜索用时 10 毫秒
171.
Namihira T. Tsukamoto S. Wang D. Katsuki S. Hackam R. Okamoto K. Akiyama H. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2000,28(1):109-114
Nitric monoxide (NO) is widely used in medical treatment of acute respiratory distress syndrome (ARDS). The production of NO is of interest to the medical community. In the present work, NO is generated by pulsed discharges between two rod electrodes in a mixture of nitrogen and oxygen. An arc discharge having a temperature of about 10000 K was produced, which was sufficient to generate NO. Some of the important parameters affecting the production of NO have been investigated. These include the percentage of O2 (6-94%) in the mixture of Na and O2, the energy of the discharge (0.5-12 J/pulse), the pulse repetition rate (0.54.5 pps) and the flow rate (1.35-5.4 l/min) of the gas mixture. NO2 produced in the discharge was successfully changed to NO using a heated molybdenum tube, NO2 must be extracted from the gas before clinical inhalation. The concentration of ozone was completely eliminated by bubbling the gas mixture through water. A maximum of NO and a minimum of NO2 concentrations were generated when the proportion of O2 in the gas mixture was in the range of 20-27%. The concentrations of NO and NO2 increased with increasing pulse repetition rate and with decreasing flow rate of the mixture. In all cases, No2 was effectively removed using a heated molybdenum tube 相似文献
172.
173.
Naphthalene in the higher triplet excited state Np(Tn) was generated from the two-step excitation method using two-colour two-laser flash photolysis technique and the lifetime of Np(Tn) was estimated to be 4.5 ps from the triplet energy quenching by quenchers such as p-dichlorobenzene, o-dicyanobenzene and carbon tetrachloride. 相似文献
174.
Lagasse F Tsukamoto M Welch CJ Kagan HB 《Journal of the American Chemical Society》2003,125(25):7490-7491
The evaluation of a racemic catalyst was investigated in the case of oxazaborolidine (OAB)-catalyzed borane reduction of 1,5-diphenyl-1,5-pentanedione, giving the corresponding diol. On the basis of the diastereoselectivity of the diols, it is possible to estimate the enantioselectivity (ee) of the first step, which correlates well with the ee in the reaction of the structurally similar phenyl n-pentyl ketone with enantiopure OAB catalyst. The measure of diastereoselectivity could be a tool for screening racemic catalysts without the need for resolving the individual enantiomers, if in the second step of the process there is no substrate control and no catalyst scrambling. 相似文献
175.
Tachikawa T Tojo S Fujitsuka M Majima T 《Langmuir : the ACS journal of surfaces and colloids》2004,20(11):4327-4329
The formation of the dimer radical cation (D*+) of 4-(methylthio) benzoic acid on a TiO2 surface is demonstrated using the time-resolved diffuse reflectance technique. The observed time-resolved diffuse reflectance spectral shape significantly depends on the substrate concentrations. The substrate concentration dependences of the initial transient signal intensity (%abs.(t=0)) and the amount of adsorbates (n(ad)) clearly suggest that the formation of D*+ is attributableto the high local substrate concentration on the TiO2 surface. The electronic influence of substituents on the formation of D*+ is also discussed. 相似文献
176.
Juzo Nakayama Ayako Tai Sachiko Iwasa Tomohiro Furuya Yoshiaki Sugihara 《Tetrahedron letters》2005,46(9):1395-1397
It was found that tetracyanoethylene oxide not only oxidizes sulfides to sulfoxides but also reduces sulfoxides to sulfides with generation of two molecules of carbonyl cyanide. The reaction thus also functions as a new method for generation of carbonyl cyanide. 相似文献
177.
Abe M Orita M Yamazaki H Tsukamoto S Teshima Y Sakai T Ohkubo T Momozawa N Sakai H 《Langmuir : the ACS journal of surfaces and colloids》2004,20(12):5046-5051
An attempt was made to arrange polystyrene latex particles (2, 5, and 10 microm in diameter) dispersed in aqueous media making use of their dielectrophoresis and electrophoresis with a hyperbolic quadruple electrode system. Application of a high-frequency ac field enabled the particles to arrange themselves between the electrodes forming a particle monolayer due to the negative dielectrophoretic force. Simultaneous application of high-frequency ac and dc fields caused the particles to gather in the region surrounded by the electrodes to form particle multilayers. Appropriate choice of the way of applying an electric field thus allowed the reversible control of particle arrangements (monolayer, multilayer, dispersion). Reapplication of an ac field to the particle layers produced highly dense particle multilayers. 相似文献
178.
Yoshimitsu Nagao Kaoru Seno Kohji Kawabata Tadayo Miyasaka Sachiko Takao Eiichi Fujita 《Tetrahedron letters》1980,21(9):841-844
3-Acylthiazolidine-2-thiones () were easily prepared and they were treated with several amines in dichloromethane to give amides in very high yields within a short time. Aminoalcohols and aminophenols were selectively converted into acylaminoalcohols and acylaminophenols, respectively, by this reaction. One can monitor the reaction by disappearance of the yellow color of the starting material . Some amide alkaloids (–) have effectively been synthesized. 相似文献
179.
Rather E Gatlin JT Nixon PG Tsukamoto T Kravtsov V Johnson DW 《Journal of the American Chemical Society》2005,127(10):3242-3243
We report the single-crystal structure of an inorganic gallium cluster [Ga13(mu3-OH)6(mu2-OH)18(H2O)24](NO3)15.6H2O prepared using a simple organic reaction to drive the formation of the crystalline inorganic cluster. 相似文献
180.
Tadashi Uragami Kenji Tsukamoto Takashi Miyata Thomas Heinze 《Cellulose (London, England)》1999,6(3):221-231
Tosylcelluloses (TosCells) with different degrees of tosylation were synthesized as membrane materials for the separation of benzene/cyclohexane (Bz/Chx) mixtures. TosCell membranes showed a high benzenepermselectivity for the Bz/Chx mixtures in pervaporation (PV). An increase in the benzene concentration in the feed mixtures increased permeation rate but decreased the benzenepermselectivity of the TosCell membranes. The increase in the permeation rate was attributed to the increase of the degree of swelling of the TosCell membranes by the feed mixtures and the decrease in the benzenepermselectivity was mainly caused by the decrease of sorption selectivity. With low benzene concentrations in the Bz/Chx mixtures, the permeation rate of a TosCell membrane with a higher degree of tosylation was greater than that with a lower degree of tosylation, but was vice versa with a high benzene concentration. The benzenepermselectivity of the former TosCell membrane was higher than that of the latter membrane. Differences of the permeation rate and benzenepermselectivity with changes in the benzene concentration in the feed mixture and degree of tosylation of the TosCell membrane were significantly influenced by the degree of swelling of the TosCell membrane and the benzene concentration sorbed into the TosCell membrane. Mechanism of separation for the Bz/Chx mixtures through the TosCell membranes is discussed by the solution–diffusion model. 相似文献