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51.
电感耦合等离子体发射光谱法间接测定氯离子和硫酸根离子的探讨 总被引:6,自引:0,他引:6
本文探讨了加入过量Ag_1~+和Ba~(2+),使Cl~-和SO_4~(2-)分别以AgCl和BaSO_4沉淀后,用ICP-AES测定剩余的Ag~+和Ba~(2+),间接测定Cl~-和SO_4~(2-)的具体方法、光谱干扰及有关影响条件。本法测定一些实际样品,结果令人满意,具有简便、快速、可与其他元素同时测定等优点。 相似文献
52.
53.
Spectroscopic and theoretical study on the interaction between diperoxovanadate and oxazole 总被引:1,自引:0,他引:1
Zeng B Zhu X Yu X Cai S Chen Z 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,69(1):117-122
Detailed investigations were carried out to explore the interaction systems of NH(4)VO(3)/H(2)O(2)/oxazole in aqueous solution under physiological conditions by a combined use of multinuclear NMR ((1)H, (13)C, (14)N and (51)V), diffusion ordered spectroscopy (DOSY), variable temperature NMR, electrospray ionization mass spectrometry (ESI-MS), spin-lattice relaxation and density functional calculations. The results indicated the formation of a new peroxovanadate species [OV(O(2))(2)(oxazole)](-) with oxazole coordinating to vanadium through nitrogen atom. The solution structure of the new species was predicted from theoretical calculations. 相似文献
54.
Poly( N-vinyl-2-pyrrolidone) (PVP)-coated Fe3O4 nanocrystals were prepared by a "one-pot" synthesis through the pyrolysis of ferric triacetylacetonate (Fe(acac)3) in N-vinyl-2-pyrrolidone (NVP). The polymerization of NVP was followed by measuring the shear viscosity of the reaction mixture. The PVP molecules formed in the reaction mixture was investigated by gel permeation chromatography. As the resultant Fe3O4 nanocrystals presented superdispersibility in 10 different types of organic solvents and aqueous solutions with different pH, including 0.01 M phosphate-buffered saline buffer, their hydrodynamic properties in both organic and aqueous systems were investigated by dynamic light-scattering. The results indicated that the PVP-coated Fe3O4 nanocrystals can completely be dispersed forming stable colloidal solutions in both organic solvents and water. Fourier transform infrared spectroscopy results suggested that PVP interacted with Fe3O4 via its carbonyl groups. Further surface analysis by X-ray photoelectron spectroscopy revealed that there were both coordinating and noncoordinating segments of PVP on the particle surface; the molar ratio between them was of 1:2.6. 相似文献
55.
The title compound has been prepared in four steps from methyl isatin-7-carboxylate. Condensations with 1-indanone and analogs gave 11H-indeno[1,2-b]quinoline-6-carboxylic acids, and with cyclohexanones gave acridine-4-carboxylic acids. 相似文献
56.
The microstructures and phases of as-cast Mg-Zn-Y alloys were investigated by means of scanning electron microscopy (SEM), energy-dispersive spectrum (EDS), X-ray diffraction (XRD), and transmission electron microscopy (TEM) in this study. Stable icosahedral Mg30Zn60Y10 quasicrystals were obtained using common casting technique. With increasing Y content, the contents of quasicrystals increased, the distribution of quasicrystals was improved, and the morphologies of quasicrystal and other microstructures of Mg-Zn-Y alloys showed different characteristics. In addition, the solidification process of Mg-Zn-Y alloys was analyzed. Icosahedral Mg30Zn60Y10 quasicrystalline phase is easy to nucleate in slow cooling. 相似文献
57.
Guisheng Zeng Xianyong Wang Shenglian Luo Hui Li Xinman Tu Xubiao Luo Jianping Zou 《Acoustical Physics》2014,60(3):356-360
The effect of ultrasound vibrations on the cooling crystallization of sodium arsenate in supersaturated solutions was investigated. In particular, the effects of ultrasound vibrations on induction time and crystal size distribution were studied using a laser-based apparatus with relative supersaturation ranging from 1.3 to 1.8. The results show that ultrasound vibrations have a significant effect on reducing induction time and crystal size distribution. The application of ultrasound vibrations to the system resulted in a small change in surface tension; however, the induction time and crystal size significantly decreased. The mean size of sodium arsenate crystals decreased from 398.87 ± 3.27 to 168.68 ± 2.07 μm, as the ultrasound power increases from 26 to 130 W. Ultrasound vibrations significantly reduced the induction time in a highly supersaturated solution compared to that in a low supersaturated solution. 相似文献
58.
The total chromatic number χT(G) of a graph G is the least number of colors needed to color the vertices and the edges of G such that no adjacent or incident elements receive the same color. The Total Coloring Conjecture(TCC) states that for every simple graph G, χT(G)≤Δ(G)+2. In this paper, we show that χT(G)=Δ(G)+1 for all pseudo-Halin graphs with Δ(G)=4 and 5. 相似文献
59.
A new class of [1,2,4]oxadiazolo[4,5‐a]thiazolo[2,3‐b]pyrimidin‐9(10H)‐one was prepared in moderate yields by the reaction of nitrile oxide with 2‐arylmethylidene‐6,7‐dihydro‐5H‐thiazolo[3,2‐a]pyrimidin‐3‐one. The reaction site of dipolarphile is the C?N of thiazolo[3,2‐a]pyrimidin‐3‐one rather than the expected C?C of arylmethylidene. The structures of the products were characterized thoroughly by IR, elemental analysis, MS, and NMR analysis. 相似文献
60.
Cai S Yu X Chen Z 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,65(3-4):616-622
To understand the substituting effects of organic ligands on the reaction equilibrium, the interactions between diperoxovanadate complex [OV(O(2))(2)(H(2)O)](-) and a series of picoline-like ligands in solution were explored using 1D multinuclear ((1)H, (13)C, and (51)V) magnetic resonance, 2D diffusion ordered spectroscopy (DOSY), and variable temperature NMR in 0.15 mol/l NaCl ionic medium for mimicking the physiological conditions. The order of reactive capability of the picoline-like ligands with [OV(O(2))(2)(H(2)O)](-) is found to be picolinamide>N-methylpicolinamide>methyl picolinate>ethyl picolinate approximately propyl picoliniate>isopropyl picolinate. The substituting group influences the reactivity by either steric effect or electron-donating effect. Competitive coordination interactions result in a series of new seven-coordinated peroxovanadate species [OV(O(2))(2)L](-) (L=picoline-like ligands). Their coordination ways were confirmed by density functional calculations. 相似文献