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41.
溴酸钾氧化亮绿SF催化光度法测定痕量亚硝酸根 总被引:27,自引:3,他引:27
本文基于亚硝酸根对溴酸钾氧化亮绿SF而使其褪色所起的催化作用,建立了高灵敏度催化吸光光度法测定痕量亚硝酸根的新方法,测定范围为0.05-20ng/ml,用于不同水样中亚硝酸根的测定,获得了满意结果。 相似文献
42.
Tonggang Jiu Yongjun Li Haiyang Gan Yuliang Li Huibiao Liu Shu Wang Weidong Zhou Chunru Wang Xiaofang Li Xiaofeng Liu Daoben Zhu 《Tetrahedron》2007,63(1):232-240
The oligo(p-phenylene vinylene)-porphyrin-oligo(p-phenylene vinylene) (P-OPVn, n=2, 4, where n is the number of phenyl rings) and the complex with Zn2+ based on P-OPVn were synthesized for investigating their photophysical properties via UV-vis, voltammetry, steady-state and time-resolved fluorescence spectra. In these molecules two OPV moieties as energy donors were linked to porphyrin center by virtue of Wittig reaction. The detailed studies of photophysical properties indicate that OPV group can act as an antenna unit for effective intramolecular energy transfer. 相似文献
43.
聚N,N-二乙基丙烯酰胺溶液粘度的温度依赖性 总被引:2,自引:0,他引:2
通过自由基聚合,合成了线型聚N,N-二乙基丙烯酰胺(PDEA),用乌氏粘度计测定并考察了该聚合物在四氢呋喃(THF)、H2O以及THF-H2O混合溶剂中粘度的温度依赖性.实验结果表明,PDEA 在上述三种溶剂中粘度的温度依赖性不同,PDEA-THF体系的相对粘度随温度升高而增大;PDEA-H2O体系以及PDEA-THF-H2O体系的相对粘度随温度升高而减小,且THF体积分数φTHF < 0.7时具有透明-白浊转变现象;对PDEA-THF-H2O体系,φTHF增加,透明-白浊转变温度升高,而当φTHF=0.7时,则观察不到透明-白浊转变现象. 相似文献
44.
Bian Y Wang R Jiang J Lee CH Wang J Ng DK 《Chemical communications (Cambridge, England)》2003,(10):1194-1195
Treatment of MIII(Pc)(acac) (M = Sm, Eu, Gd; Pc = phthalocyaninate; acac = acetylacetonate), generated in situ, with 3-(3-pentyloxy)phthalonitrile in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in n-pentanol affords racemic mixtures of the chiral double-deckers MIII(Pc)[Pc(OC5H11)4] [Pc(OC5H11)4 = 1,8,15,22-tetrakis(3-pentyloxy)phthalocyaninate], which have been spectroscopically and structurally characterised. 相似文献
45.
Thermodynamics and dynamics of metallic glass formers: their correlation for the investigation on potential energy landscape 总被引:3,自引:0,他引:3
Great progress has been made in basic features of the potential energy landscape (PEL) theoretically. The present work, however, attempts to cast new light on it from experimental aspects. By a survey of experimental data related to thermodynamics or dynamics of metallic glass-forming liquids, it is found that the increased rate of excitation of vibrational entropy at glass transition tends to increase the rate of generation of configurational part. Although for the type of metallic materials a generally positive relationship exists between the density of the energy minima at glass transition and the liquid fragility strength, just as expected, our main attention is paid to the phenomenon of the scattering of the slopes. Analysis shows that the phenomenon results from the different average height of energy barriers between minima near glass transition. Investigation on the PdNiP metallic system indicates that the mismatch entropy is a dominant factor in the barrier height: a large value of it results in low energy barriers. Our previous work on the AlNiCe system gives the support to this finding. 相似文献
46.
Prompted by samarium metal in DMF with TMSCl or iodine as an activator, or by SmI2/THF system, diarylmethanones react readily with DMF to afford benzoins in moderate to good yields via rearrangement of aryl groups. As for asymmetric diarylmethanones, products resulting from the migration of either aryl group were obtained, where the migration of aryl groups shows certain priority. 相似文献
47.
Li-an Bian Peiguo Liu Qihui Zhou Chenxi Liu Hanqing Liu Song Zha 《Optical and Quantum Electronics》2018,50(5):220
Total absorption is realized theoretically in a graphene-outside-cavity resonator. The structure is composed of the FP-Fano hybrid resonance cavity. Changing the thickness of grating exciting Fano resonance, the absorption-mode number can be tuned effectively. For the focused double-mode absorption, the resonances behave insensitively with the variation of chemical potential of graphene. Varying the geometry of grating can control the coupling extent of two modes. Also, by manipulating the period number of two-side multilayers around graphene, the absorption, shift and number of modes are governed. 相似文献
48.
Wang Kang Xingqiong Du Lanzhi Wang Lijuan HU Yuhuan Dong Yanqing Bian Yuan Li 《中国化学》2013,31(10):1305-1314
Our studies examined the structural features responsible for the antifungal activity of 2-ethoxycarbonyl-1,5- benzothiazepine (7a). Three series of 1,5-benzothiazepine derivatives were synthesized and screened for their antifungal activity. The results suggested that the ethoxycarbonyl group at the 2 position and the imine moiety on the seven-membered ring are essential for activity. The most potent of the synthesized analogues (7a, 7b) were further studied by evaluating their cytotoxicity and mode of action (for 7a). The results showed that compounds 7a and 7b were relatively safe for BV2 cells, but compound 7a interfered with Cryptococcus neoformans cell wall integrity by increasing the chitinase activity. Therefore, compound 7a was considered safe as an antifungal agent for animal cells. 相似文献
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