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621.
622.
623.
The signal-to-noise ratio (SNR) in the photochromic super-resolution readout of optical disks was theoretically analyzed. The shot noise limited SNR, such as that in magnetooptical disks, was improved only for the short recorded mark. However, the media noise limited SNR, such as that in phase change disks, was greatly improved for both short and long recorded marks. 相似文献
624.
Trifluoromethyl trifluoromethanesulfonate () was synthesized by the reaction of silver trifluoromethanesulfonate with trifluoromethyl iodide in a benzene solution. Reaction of with an enamine gave trifluoromethanesulfonyl compound. This is the first example of SO2-O bond fission of alkyl trifluoromethanesulfonate. 相似文献
625.
Taizo Ono Yoshihisa Inoue Chikara Fukaya Yoshio Arakawa Youichiro Naito Kazumasa Yokoyama Kouichi Yamanouchi Yoshiro Kobayashi 《Journal of fluorine chemistry》1985,27(3):333-346
Electrochemical fluorination of 2-methoxy-1,1,1-trifluoro-2-(F-methyl) octane gave the corresponding perfluorinated ether in 27% yield, along with cyclic by-products in 9%. A mixture of partly fluorinated tertiary amines, consisting of 1-dipropylamino-F-1-propene and 1-dipropylamino-2-hydryl-F-propane, did not afford a superior yield of tri(F-propyl)amine compared to the unfluorinated tripropylamine. 1-Diethylamino-2-(F-methyl)-F-1-pentene was fluorinated to give the corresponding F-tertiary amine in fairly good yields, together with 1-di(F-ethyl)amino-2-hydryl-2-(F-methyl)-F-pentane and their fragmented products. The study indicates that blocking of the α-carbon atom of an ether with F-methyl groups seems to reduce fragmentation, resulting in good yields of an unrearranged product. However, partial fluorination of a tertiary amine prior to electrochemical fluorination rather allows high yields of undesired by-products, as far as our experiments were concerned. 相似文献
626.
627.
628.
Yoshiro Sato Shin-ichi Ninomiya Feng-Zhi Liu Naohiro Shirai Yutaka Kawazoe 《Tetrahedron letters》1985,26(45):5547-5550
The rate for hydrolysis, chemoselectivitly toward nucleophiles, and partition property of N-neopentyl-, N-trimethylsilylmethyl-, and N-trimethylgermylmethyl-N-nitrosoureas were compared. The latter two compounds are silicon and germanium analogues of the neopentyl derivative. The substitution effect of Ge in place of Si or C are discussed on the chemical and physicochemical properties. 相似文献
629.
We have experimentally observed and theoretically identified a novel class of purely long-range molecules. This novel purely long-range state is formed due to a very weak hyperfine interaction that is usually treated only as a small perturbation in molecular spectra. Photoassociation spectroscopy of ultracold ytterbium (171Yb) atoms with the 1S0-3P1 intercombination transition presents clear identification of molecular states and the shallowest molecular potential depth of about 750 MHz among the purely long-range molecules ever observed. 相似文献
630.
A diarylethene derivative bearing a phenylenediamine group formed radical ions with an electron acceptor molecule in solution, and the concentration of the radical ions was modulated by the photochromic reaction of the diarylethene, reflecting the difference in the electron-donating character between the open- and closed-ring isomers. 相似文献