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851.
A procedure for the Raman spectra calculation of vitreous and molten silicates was presented in this paper. It includes molecular dynamics MD simulation for the generation of equilibrium configurations, Wilson's GF matrix method for the calculations of eigenfrequencies and corresponding vectors, electro-optical parameters method (EOPM) for the Raman intensity calculations, and the bond polarizability model (BPM) for the determination of polarizability and polarizability derivative. One of the most important characteristics of this procedure is the achievement of the partial Raman spectra of five tetrahedral units, as well as the total spectral envelope. In this paper, the calculation was carried out for the vitreous and molten calcium silicates with different compositions and at various temperatures. It is worthwhile to note that the calculation is based on statistical configurations distribution in the space and so it is not needed to artificially adjust the full width at half maximum (FWHM) of spectra. It was also tested through the good agreement of the calculated spectra with the experimental, including some regularity of spectral properties. According to the calculation, the symmetrical stretching of whole tetrahedral units, to which the stretching of Si-O(nb) bond gives the main contribution to intensity, is proven to be the dominance in the high-frequency range (800-1200 cm(-1)) and the symmetrical bending of Si-O(b)-Si, to which the stretching of Si-O(b) bond exhibits the main contribution, is the dominance in the medium-frequency range (400-700 cm(-1)). As the first theoretical results, the Raman scattering coefficient of each Q(i) was found little change along with the variation of composition and temperature. 相似文献
852.
The volatile chemical constituents of Artemisia capillaries (an important traditional Chinese medicine) were determined by gas chromatography-mass spectrometry (GC-MS) and sub-window factor analysis (SFA). Seventy-five components were separated and 43 of them were qualitatively and quantitatively determined, which represented about 89.03% of the total content. This profile was then used to identify and assess the consistency of the herb by using an orthogonal projection method. Four different sources of A. capillaries were analyzed and compared with each other. Among the components determined, there were 51 components coexisting in all samples although the relative peak areas of a few showed variations. It is the first time to apply orthogonal projection method to the comparison of different samples, and it reduces the burden of qualitative analysis as well as the subjectivity. The results showed a fair consistency in their GC-MS fingerprint. A. capillaris was distinguished from Artemisia sacrorum L., a possible substitute in traditional Chinese medicine by comparing the fingerprints with each other. 相似文献
853.
Zhang P Li J Liu D Qin Y Guo ZX Zhu D 《Langmuir : the ACS journal of surfaces and colloids》2004,20(4):1466-1472
A C60-pyrrolidine derivative with a hydrophobic-hydrophilic-hydrophobic structure (2-{3,4-di{2-[2-(2-decyloxyethoxy)ethoxy]ethoxy}}phenyl-3,4-fulleropyrrolidine, DTPF) has been synthesized and well-characterized. This compound could form stable nanospheres by simply injectingits tetrahydrofuran (THF) solution into water and then removing THF by purging gaseous nitrogen in sequence. Novel nanoassemblies of DTPF nanospheres and gold nanoparticles were obtained through in situ photoreduction of aqueous HAuCl4 in the presence of DTPF nanospheres, which were confirmed by UV-visible, transmission electron microscopy, X-ray powder diffraction, and X-ray photoelectron spectroscopy methods. It is proposed that the interaction between the positively charged nitrogen atom and the gold nanoparticles is the main driving force for the formation of the nanoassemblies. 相似文献
854.
Guo Zhijun Niu Yanning Zhang Weiguang Tan Minyu 《Journal of Radioanalytical and Nuclear Chemistry》2004,262(2):331-337
N,N,N',N',N',N'-Hexaethyl-2,2′,2'-(nitrilotrisethyleneoxy-2-benzyloxy)tris(acetamide) (L3) has been prepared and characterized
by using IR, 1H NMR and positive-ion FAB mass spectra. The extraction of Th4+ and UO2
2+ with N,N,N',N',N',N'-hexaethyl-2,2',2'- (nitrilo-trisethyleneoxy)tris(acetamide) (L1), N,N,N',N',N',N'-hexaisopropyl-2,2',2'-(nitrilotrisethyleneoxy)tris(acetamide)
(L2), and L3 was studied at 20±1 °C as a function of diluent, concentration of free extractant in organic phase and concentration
of picrate in aqueous phase. It was found that the extracting powers of L1 and L2 for Th4+ are almost identical. The extracting power of L2 for UO22+ was slightly higher than that of L1. The difference in terminal
groups (ethyl or isopropyl) of the extractants (L1 and L2) with same backbone has a little effect on the extracting power
for both Th4+ and UO22+. The extracting powers of L3 for both Th4+ and UO22+ were larger than those of L1 and L2. The extractants
(L1 and L3) having the same terminal group (ethyl) with different backbones have obviously different extracting powers for
Th4+ or UO22+. The extracting powers of all three extractants L1, L2, and L3 for Th4+ were larger than those for UO22+. The
compositions of extracted species in organic phase were predominantly ThL(Pic)3NO3 and UO2L(Pic)NO3, respectively (L denotes
L1, L2 and L3).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
855.
Guo Jin-xin Sun Si-xiu Zhu Rong-xiu Yin Zhi-lei Yu Hai-yun Li Da-zhi Zhang Wei-min Xu Xian-gang Sun Xuan Shao Hua 《Journal of Radioanalytical and Nuclear Chemistry》2004,261(1):221-224
The 222Rn emanation fraction (EF) released from the technically enhanced naturally occurring radioactive material (TE-NORM) wastes
at certain sites of petroleum and gas production was determined. The samples were analyzed by γ-ray spectrometry to determine
the activity concentration of the 226Ra content, of which the 222Rn emanation fraction was calculated. The results showed that the 222Rn emanation fraction differs in the oil and gas production sites and it is independent of the activity concentration of 226Ra.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
856.
The hydrogen bond is one of the most important intermolecular interactions playing an important role in intermolecular recognition processes essential to most biological systems. Adrenaline is an important catecholamine neurotransmitter in the mammalian central nervous system. Dimethyl sulphoxide can carry with it drugs across membranes. The geometries of adrenaline and six stable 1 : 1 complexes formed between adrenaline and dimethyl sulphoxide were optimized by Berny method at PM3 level and thus were optimized by density functional theory(B3LYP method)at the 6-31G,6-31G*,and 6-31+G* level respectively to obtain accurate structures. Single-point energies of all optimized molecular geometries were calculated to discuss the energies and structural parameters between reactants and products. All the binding energies have been corrected by the zero point vibrational energies(ZPVE)at varied basis set levels from 6-31G to 6-31 + G*. The results indicated that stronger hydrogen-bonded complexes were formed by molecular interaction between adrenaline and dimethyl sulphoxide. The calculation results can be better used to explain some experimental phenomena. 相似文献
857.
Shiliang He Hang Zhao Xiurong Guo Guang Xin Baozhan Huang Limei Ma Xinglong Zhou Rui Zhang Dan Du Xiaohua Wu Zhihua Xing Wen Huang Qianming Chen Yang He 《Tetrahedron》2013
J-AT nucleoside-based organogelators 1a and 1b were designed and synthesized. They were endowed with unparalleled superiority to natural nucleobase analogues 2–6 to gelate aromatic solvents due to their excellent self-assembly properties. The J-AT nucleoside-based organogelators showed a specific self-complementary base pair recognition characteristic. The gel stabilities of 1a and 1b were drastically influenced by adenine analogue 2, hardly affected by thymine analogue 3, uracil analogue 4, cytosine analogue 5, and mildly interrupted by guanine analogue 6. 相似文献
858.
Synthesis and Characterization of Dual Acidic Ionic Liquids 总被引:1,自引:0,他引:1
Xiao Hua WANG Guo Hong TAO Zi Yan ZHANG Yuan KOU 《中国化学快报》2005,16(12):1563-1565
Novel ionic liquids with dual acidity, of which the cation contains Brφnsted acidity and anions contain Lewis acidity were synthesized. These ionic liquids obtained were identified by NMR, FF-IR, SDT and FAB-MS. Their acidities were determined by pyridine probe on IR spectrography. 相似文献
859.
GuoQiangLI XiangLI ZhiWeiDENG HuaShiGUAN WenHanLIN 《中国化学快报》2005,16(4):494-496
Two new compounds, namely 7α, 10α-dimethyl-3β-isopropene-1, 2-ene-octahydro-naphthalene (1) and ethyl 5Z,8Z, 11Z, 14Z-nonadecatetraenoate (2) were isolated from the soft coralNephthea hainansis. Compound 1 was a pseutosesquiterpene and 2 was a polyunsaturated fattyacid ethylate. Their structures were established on the basis of spectroscopic methods. 相似文献
860.
WenFeiWANG QiangZHENG HongGuoHU WeiWeiLIN 《中国化学快报》2005,16(5):671-674
A novel organosilane, N-n-butyl-γ-aminopropylmethyldimethoxysilane was synthesized through aminization reaction and the chemical structure of resulting products was characterized by ^1HNMR, ^13CNMR, FT-IR and elemental analysis. The results of test on probation for this organosilane proved that it was effective to modify surface-paintability of organosiloxane sealants. 相似文献