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151.
Generation of sub-10-fs pulses with an average power of 1 W and a peak of 1.5 MW from a Kerr-lens mode-locked mirror-dispersion-controlled Ti:sapphire laser is demonstrated. A specially designed lens triplet focuses the output of this compact all-solid-state source to a peak intensity in excess of 5x10(13) W/cm (2) . Nonperturbative nonlinear optics is now becoming feasible by use of the output of a cw mode-locked laser. 相似文献
152.
153.
Designed ferromagnetic, ferroelectric Bi(2)NiMnO(6) 总被引:1,自引:0,他引:1
Azuma M Takata K Saito T Ishiwata S Shimakawa Y Takano M 《Journal of the American Chemical Society》2005,127(24):8889-8892
A newly designed ferromagnetic, ferroelectric compound, Bi(2)NiMnO(6), was prepared by high-pressure synthesis at 6 GPa. The crystal structure, as determined by synchrotron X-ray powder diffraction, is a heavily distorted double perovskite with Ni(2+) and Mn(4+) ions ordered in a rock-salt configuration. The presence of 6s(2) lone pairs of Bi(3+) ions and the covalent Bi-O bonds give ferroelectric properties with T(CE) of 485 K, while -Ni(2+)-O-Mn(4+)-O-Ni(2+)- magnetic paths lead to a ferromagnetism with T(CM) of 140 K. This simple material design to distribute two magnetic elements with and without e(g) electrons on B sites of Bi- and Pb-based perovkites can be applied to other Bi(2)M(2+)M'(4+)O(6) and Pb(2)M(3+)M'(5+)O(6) systems to search for newer ferromagnetic ferroelectrics. 相似文献
154.
Treatment of the acetylene-coordinated tetrairon cluster, [(eta5-C5H4Me)4Fe4(HCCH)2]+, with N-bromosuccinimide led to stepwise bromination of two acetylene ligands to form [(eta5-C5H4Me)4Fe4(HCCBr)(HCCH)]+, [(eta5-C5H4Me)4Fe4(HCCBr)2]+, [(eta5-C5H4Me)4Fe4(BrCCBr)(HCCBr)]+, and [(eta5-C5H4Me)4Fe4(BrCCBr)2]+. The reactivity of the bromoacetylene fragment in [(eta5-C5H4Me)4Fe4(HCCBr)(HCCH)]+ toward water, pyridine, and ZnMe2 was also investigated. 相似文献
155.
Lopes PS Kaneko TM Takano CY Lacerda AC Latorre LR Kato MJ 《Journal of AOAC International》2003,86(4):681-684
A validated method was developed for determination of diclofenac sodium, considered a model hydrophilic drug for in vitro permeation studies, in Eagle's Minimum Essential Medium (MEM) with Earle's balanced salt solution. Liquid chromatography was used to determine diclofenac sodium. This method was developed with a reversed-phase column Supercosil LC 18, DB 25 cm x 4.5 mm; the mobile phase was methanol with 3% (v/v) acetic acid-Milli-Q water (74 + 26), and detection was at 283 nm. The detection and quantitation limits were 2.41 x 10(-8) and 3.31 x 10(-5) microg/microL, respectively. The accuracy within-day (n = 3) and day-to-day (n = 7) was 98.83%; the mean variation coefficient for inter- (n = 7) and intraday precision (n = 3) was 12.20%, thus, not exceeding 15%. This method can be used as an analytical procedure for the determination of diclofenac sodium in MEM for in vitro permeation studies. 相似文献
156.
Fujio Mizukami Yoshimichi Kiyozumi Tsuneji Sano Shu-ich Niwa Makoto Toba Shigemitsu Shin 《Journal of Sol-Gel Science and Technology》1998,13(1-3):1027-1031
Amorphous alumina-silicas were prepared from a tetra-alkoxysilane and anhydrous aluminum trichloride or an aluminum alkoxide by a sol-gel process using 2-methyl-2,4-pentanediol, pinacol, 1,2-propanediol, 2,3-butanediol or ethylene glycol as the solvent or complexing agent, and the effect of diols and alkoxy groups on the physical and chemical properties of the alumina-silicas was examined. When the diol or the alkoxy group was bulky, the alumina-silicas had relatively larger micropores, a larger pore volume and higher surface areas. In the conversion of methanol catalyzed by the alumina-silicas, the bulkier diols and alkoxides gave catalysts that produced dimethyl ether in higher yield and hydrocarbons in lower yield. Thus, when ethylene glycol was used as the diol, the best catalyst for the production of hydrocarbons, especially the production of olefins such as ethylene, propylene and butene, was obtained. Furthermore, in comparison with alumina-silica prepared by a traditional kneading process, it was found that the sol-gel alumina-silica could efficiently convert methanol to dimethyl ether and hydrocarbons, but the material prepared by kneading had a very low conversion of methanol to other compounds. 相似文献
157.
Hidetsugu Wakabayashi Akifumi Takano Kimio Shindo Masafumi Yasunami Jhy-An Chen Paw-Wang Yang Tetsuo Nozoe 《中国化学会会志》1996,43(4):301-304
Oxidation of 1-ethyl-, 1-propylazulenes, and their 5-isopropyl derivatives with bromine gave 3-bromo-1,5- and 3-bromo-l,7-azulenequinones (Type A) together with 3-bromo-l-hydroxy-5-isopropyl-l-alkylazulen-7-one and its isomeric products (Type B), while the same reaction of 1-methylazulenes afforded Type B products along with many unidentified products. On the other hand, 1-phenylazulene gave 3-phenyl-1,5- and 3-phenyl-l,7-azulenequinones (Type C) and Type B products in high yie]ds. 1,2-Polymethyleneazulenes afforded a considerable amount of 3-bromo-2-(ω-formylalkyl)azulenequinones together with Type B products. Possible pathways for the extrusion of the alkyl substituent at C-l are discussed. 相似文献
158.
1-(2-Mercaptoethyl)phthalazine (VII) and its analogs such as S-2-(1-phthalazyl)ethyliso-thiuronium bromide (VI), sodium S-2-(1-phthalazyl)ethylthiosulfate (VIII), 1,3-bis-acetylthio-2-(1-phthalazyl)propane (XII), 2-(1-phthalazyl)-1,3-propanedithiol (XIII), disodium 2-(1-phthalazyl)-1,3-propanedithiosulfate (XIV), 3-dimethylamino-2-(1-phthalazyl)-1-propanethiol (XVII) and 3-(4-methyl-1-piperazinyl)-2-(1-phthalazyl)-1-propanethiol (XIX) have been prepared as potential radiation protection agents. 相似文献
159.
Yoshikatsu Akiyama Fujio Mizukami Yoshimichi Kiyozumi Kazuyuki Maeda Hiroyuki Izutsu Kengo Sakaguchi 《Angewandte Chemie (International ed. in English)》1999,38(10):1420-1422
Helices composed of stacked layers are present in the novel silicate obtained from a silica sol and NaOH by hydrothermal synthesis in the presence of tetramethylammonium (TMA) hydroxide and 1,4-dioxane. The helical morphology is evident in scanning electron micrographs (see picture). The TMA and sodium ions of the silicate are readily replaced by protons, and on heating to 200°C a reversible phase transition occurs in which water molecules are lost from between the layers. 相似文献
160.