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141.
G.W.C. Hung 《Microchemical Journal》1977,22(2):157-167
A gas Chromatographic method for a rapid, direct microquantitative determination of cyclohexanone in physiological solutions and biological fluids is described. The retention behavior of some volatile organic compounds is also presented. The effect of column temperature on the retention behavior of cyclohexanone is briefly discussed. Other Chromatographic factors which might affect the analytical results are mentioned. 相似文献
142.
The formation and evolution of the solid electrolyte interphase (SEI) film on the surface of natural graphite spheres in the electrolyte of 1 M LiPF6 in ethylene carbonate (EC) and dimethyl carbonate (DMC) (volume ratio 1:1) were investigated with use of focused ion beam (FIB) technology. Secondary electron FIB images clearly show the surface and cross-section morphology of the SEI film. The composition variation along the surface and cross section of the SEI film was also explored by the elemental line scan analysis (ELSA). The initial SEI film with an apparent thickness range of approximately 450 to approximately 980 nm is rough in morphology and nonuniform in composition, and contains small splits. After certain electrochemical cycles, the thickened SEI film displays microscale holes and obvious cracks on the surface, and the content of organic compounds increases. In addition, the concept of "internal SEI film" is first proposed based on the characterization of the cross section of the natural graphite spheres with the aid of FIB. Finally, the capacity fading mechanisms of the natural graphite spheres corresponding to different electrochemical stages are discussed. 相似文献
143.
Hung CH Chang FC Lin CY Rachlewicz K Stepień M Latos-Grazyński L Lee GH Peng SM 《Inorganic chemistry》2004,43(14):4118-4120
Iron and copper complexes of tetraphenyl-m-benziporphyrin (TPmBPH)H have been prepared and structurally characterized. The iron system, (TPmBPH)Fe(II)Br, contains a high-spin Fe(II) center. In the solid state the complex forms dimeric units linked by weak CH.Br hydrogen bonds. The Cu complex contains a tetrameric copper cluster with a Cu(2)Cl(4)(2)(-) unit bridging two [(TPmBPCl)Cu(II)](+) fragments. The formation of (TPmBPCl)H represents an example of copper-catalyzed chlorination on the internal carbon atom of (TPmBPH)H. 相似文献
144.
N-heterocyclic carbenes as highly efficient catalysts for the cyclotrimerization of isocyanates 总被引:2,自引:0,他引:2
[reaction: see text] A series of N-heterocyclic carbenes (NHCs) were evaluated as potential catalysts for the cyclotrimerization of isocyanates to afford isocyanurates. 1,3-Bis-(2,6-diisopropylphenyl)-4,5-dihydroimidazol-2-ylidene (SIPr) was found to be a highly efficient catalyst for the cyclotrimerization of a variety of isocyanates. 相似文献
145.
Huang YW Hu ST Yang SY Horng HE Hung JC Hong CY Yang HC Chao CH Lin CF 《Optics letters》2004,29(16):1867-1869
When an external magnetic field is applied parallel to the film surface of a magnetic fluid film, a high-quality one-dimensional periodic chain structure is formed when the field strength reaches a certain level. With a periodic chain structure in the magnetic fluid film, an incident light is diffracted onto the magnetic thin film. The results show that the one-dimensional periodic chain structure in the magnetic fluid film can serve as an optical grating. Further investigations reveal the feasibility of developing tunable coarse wavelength-division multiplexing by utilizing a periodic chain structure. 相似文献
146.
Liu CW Hung CM Haia HC Liaw BJ Liaw LS Tsai YF Wang JC 《Chemical communications (Cambridge, England)》2003,(8):976-977
The novel halide-centered Ag(I)8 cubic clusters containing diethyl diselenophosphato ligands are prepared and their solid state structures, a discrete unit or a one-dimensional chain, are dictated by the counter anions. 相似文献
147.
Fractionation of the ethanolic extract of the seeds of Calophyllum inophyllum L. has resulted in the isolation of four novel pyranocoumarin derivatives, designated as inocalophyllins A (1), B (2) and their methyl esters (3, 4) in addition to the known calophyllolide. The structures of these compounds have been determined on the basis of spectroscopic analysis including MS, heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond connectivity (HMBC) and two dimensional incredible natural abundance double quantum transfer experiment (2D-INADEQUATE). Two new methylated products, 5 and 6 were also prepared by methylation of compounds 1 and 2, respectively. 相似文献
148.
Protonation and bromination of an osmabenzyne: reactions leading to the formation of new metallabenzynes 总被引:1,自引:0,他引:1
Wen TB Ng SM Hung WY Zhou ZY Lo MF Shek LY Williams ID Lin Z Jia G 《Journal of the American Chemical Society》2003,125(4):884-885
The reactivities of benzynes and metal-carbyne complexes are normally associated with the triple bond units. However, we have now found that electrophiles do not attack the formal osmium-carbon triple bond of osmabenzyne complex 1. Instead, 1 undergoes electrophilic substitution reactions-the typical reactions of aromatic systems. 相似文献
149.
150.
Simultaneous writing and probing of photoinduced second-order susceptibility chi((2)) in an azo-dye polymer thin film is demonstrated. The method is based on the fact that tensor properties of chi((2)) provide different planes of polarization for seeding and signal second harmonics. Our technique allows the chi((2)) value to be monitored in real time, completely eliminating the distortion of optical poling that can occur in traditional probing configurations. The possibility of attaining high values of chi((2)) in a DR1-PMMA guest?host system under low seeding intensities is shown. 相似文献