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121.
采用大功率高重复频率准分子激光溅射热解石墨靶制备了类金刚石碳膜, 研究了实验条件对类金刚石膜光学性能的影响, 发现氢可以提高膜中sp3键的含量和膜的光学透过率. 在实验参数范围内, 膜的光学性能随着氢压的增加而提高. 根据类金刚石膜的反应沉积机理对上述结果进行了分析、解释. 相似文献
122.
The reaction between Cr(CO)5[C6H6] and ethyl diazoacetate (EDA) has been studied using the technique of laser flash photolysis. Results indicate that the Cr(CO)5 fragment reacts very rapidly with the EDA ligand. Low temperature spectroscopic studies suggest that in the case of W(CO)5, and by analogy also in the case of Cr(CO)5, the initial adduct between the pentacarbonyl fragment and EDA is one where the oxygen atom of the diazocarbonyl ligand is bound to the metal center. This kinetic product is then converted to a thermodynamically favored complex which is tentatively assigned as the nitrogen bound W(CO)5-EDA complex that appears to be stable at r.t. 相似文献
123.
用WAXD和SAXS方法研究了聚酰胺1010的聚集态结构和结晶结构的辐射损伤过程和机理。辐射交联与裂解主要在非晶区和结晶表面或中间相发生;辐射损伤并从这里开始,随辐射剂量增大,非晶化逐渐向晶区伸展,有氢键的(010)晶面损伤几率高于(100)晶面;辐射后效应导致新的交联与裂解生成,主要影响(010)晶面的形成与完善,使L100及Wc变小。 相似文献
124.
The study of curium iodate, Cm(IO3)3, was undertaken as part of a systematic investigation of the 4f- and 5f-elements’ iodates. The reaction of 248CmCl3 with aqueous H5IO6 under mild hydrothermal conditions results in the reduction of IO65− to IO3− anions, and the subsequent formation of Cm(IO3)3 single crystals. Crystallographic data are: (193 K, MoKα, ): monoclinic, space group P21/c, , , , β=100.142(2)°, V=811.76(14), Z=4, R(F)=2.11%, for 119 parameters with 1917 reflections with I>2σ(I). The structure consists of Cm3+ cations bound by iodate anions to form [Cm(IO3)8] units, where the local coordination environment around the curium centers can be described as a distorted dodecahedron. There are three crystallographically unique iodate anions within the structure; two iodates bridge between three Cm centers, and one iodate bridges between two Cm centers and has a terminal oxygen atom. The bridging of the curium centers by the iodate anions creates a three-dimensional structure. Three strong Raman bands with comparable intensities were observed at 846, 804, and 760 cm−1 and correspond to the I-O symmetric stretching of the three crystallographically distinct iodate ions. The Raman profile suggests a lack of inter-ionic vibrational coupling of the I-O stretching, while intra-ionic coupling provides symmetric and asymmetric components that correspond to each iodate site. Repeated collection of X-ray diffraction data for a crystal of Cm(IO3)3 over a period of time revealed a gradual expansion of the unit cell from self-irradiation. After 71 days, the new parameters were: , , , β=100.021(2)°, V=818.3(2). 相似文献
125.
Time-of-flight mass spectrum of C_nB~- has been recorded on a selfbuilt instrument with laser vaporization of tetraphenylboron sodium. By analysis of the com-position of the anions, it is found that number of the boron atoms in any of these ions equals to the number of the charges carried by the anion, and the sum of the numbers of the carbon and boron atoms in these species are always the odd numbers. The experimental results show that boron atom has a strong tendency to attract an electron so that those C_nB~- will have similar electronic structures as C_n, and carbon clusters with odd members are always more stable than their even neighbors. 相似文献
126.
Ferdous Khan Diana Kwek E. Kronfli S.R. Ahmad 《Polymer Degradation and Stability》2007,92(8):1640-1644
Excimer laser-induced crosslinking of ethylene-propylene-diene elastomer using a trace amount of photoinitiator, 1-hydroxy cyclohexyl phenyl ketone, was evaluated. Gel content measurements on irradiated samples showed that crosslinking was a natural consequence in all, which had undergone exposure to laser radiation. Degree of crosslinking was found to be linear with the laser exposure energy and was found to reach a saturation value of approximately 80% at about 100 J. However, for thicker samples the dependence of gel content i.e. crosslinking was found to be exponential over the range of laser exposure energy in excess of 200 J. As is expected, the tensile strength increased significantly with the increase of crosslinking. The band at 808 cm−1 in the infrared spectra was attributed to the 5-ethylidene-2-norbornene (ENB) content in the polymer. The ENB has a double bond which is considered to be consumed with a high radiochemical yield and thereby contributes to the increase in rate of the formation of intermolecular bridge density. 相似文献
127.
合成了E,E-1,4-二[2′,2″-(苯并(口恶)唑基乙烯基)]苯及衍生物共14种,测定了它们的熔点、红外光谱、核磁共振氢谱、紫外吸收光谱和荧光发射光谱、荧光量子产率及激光性能。 相似文献
128.
Over the past few years, a large number of studies have been prepared that describe the analysis of peptides and proteins using capillary electrophoresis (CE) and laser-induced fluorescence (LIF). These studies have focused on two general goals: (i) development of automatic, selective and quick separation and detection of mixtures of peptides or proteins; (ii) generation of new methods of quantitation for very low concentrations (nm and subnanomolar) of peptides. These two goals are attained with the use of covalent labelling reactions using a variety of dyes that can be readily excited by the radiation from a commonly available laser or via the use of noncovalent labelling (immunoassay using a labelled antibody or antigen or noncovalent dye interactions). In this review article, we summarize the works which were performed for protein and peptide analysis via CE-LIF. 相似文献
129.
130.