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1.
By using ultrasonic and chemical liquid coprecipitation, the precursor was prepared with high purity In, SnCl 4·5H 2O and urea. The In 2O 3·SnO 2 nanonets were obtained from precursor by heating in microwave oven. The powders were characterized by XRD, TEM. The analyzed results show the sample is In 2O 3·SnO 2, and In 2O 3is rhombohedral system while SnO 2 is tetragonal system. The sample is in spherical grain shape, with average granularity of 35 nm, and the mesh diameter of 10~80 nm. The sample was with fluorescence and good photocatalytic performance for degradation of organic dyestuff. 相似文献
2.
Monodispersed superfine ZnO powders with particle size of about 200~400nm were successfully prepared by the decompressed distillation process with n-butyl alcohol as the solvent. The starting materials were Zn(NO 3)2·6H 2O and NH 3·H 2O. TG-DSC, XRD, TEM and BET surface areas techniques were used to characterize the precursor and as-prepared superfine ZnO powders. In the preparation process of superfine ZnO powders, two techniques including the decompressed distillation with n-butyl alcohol and washing with absolute ethanol were used to avoid agglomeration. It is showed that the decompressed distillation process has a better effect in avoiding ag-glomeration than washing with absolute ethanol. The precursor obtained by the decompressed distillation technique has a lower calcination temperature than the one obtained by washing with absolute ethanol. Zincite phase of ZnO with some impurities was obtained when the precursor was calcined at 200℃ for 2h. After it was calcined at 300℃ for 2h, pure superfine ZnO powder was obtained. 相似文献
3.
Nanometer SnO 2 powders were successfully prepared by non-hydrolytic sol-gel approach combined with heat treatments using tin tetrachloride as starting material and ethylene glycol as solvent. The reaction mechanism of the sol-gel process is proposed. Results indicate that the -OHCH 2CH 2OH- prevent Cl - ion from accessing to tin Sn 4+ due to steric effect, and hence increaseing the stability of the sol solution. Ethylene glycol functions not only as a complextion agent to form a polymer network but also as a “spacer” to modulate the distance between metal ions, preventing metal oxide particles from aggregation during desiccation of the sol. The effects of heat treatments on the evolution of structure and morphology of nanosized SnO 2 powders were studied. The powders with narrow size distribution around 15~20 nm could be obtained at 500 ℃ for 4 h. 相似文献
4.
Spinel LiMn 2O 4 powders were prepared using two-step synthesis method consisting of solid-state reaction method and citrate modified sol-gel method. The effects of the calcination temperature and the Li/Mn ratio of raw materials were studied on the physicochemical and electrochemical properties of the spinel LiMn 2O 4 powders, such as crystallinity, lattice constant and density. The title compound was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Polycrystalline LiMn 2O 4 powers calcined at 750 ℃ were found to be composed of very uniformly-sized microcrystal with an average particle size of 300 nm. The improvement in electrochemical properties was mainly attributed to the process of re-grinding by absolute alcohol. 相似文献
5.
Preparation of In 2O 3nano-scale powders by ultrasonic and homogeneous precipitation, using metal In and urea as raw materials, was reported for the first time, while the effects of reaction temperature, the ratio of the materials and the pH etc. on the preparation was dicussed. This method can be operated and industrialized easily with very low cost. The structural properties of precursor and In 2O 3were characterized by TG-DTA, XRD, ESCA and TEM. The results show that In 2O 3produced are very pure, monophase and spherical nano-scale powders with average size of 25 nm. 相似文献
6.
The Ti/SnO 2-Sb 2O 4 electrode has been prepared by the electroplate-sinter method. The effect of SbCl 3 adding amount and sintering temperature on its electrode lifetime and oxygen evolution potential were investigated by means of EDX, SEM and XRD analysis. The results indicated that the electrode appeared the best performance when the SbCl 3 adding amounts was 0.2g and the sintering temperature was 550℃. In optimized conditions Ti substrate was entirely covered by SnO 2-Sb 2O 4 and the combinations among them were tight. Due to the use of electroplate method, the electrical conductivity, the oxygen evolution potential and the electrode lifetime were increased, so the elec-tro-catalytic activity and the electrochemical stability of the prepared electrode were found to be superior. 相似文献
7.
The SnO 2 nanocrystaline powders were synthesized by citric acid dissolution-pyrolysis method. The medium products were analyzed by FTIR. The products were characterized by TG-DTA, XRD, TEM, SEM etc. The results showed that the Sn was coordinated with aconitase acid during the dissolution. The SnO 2 particles prepared by this method were with a mean size of 5~10 nm. The calcined products presented lacunose micro-arc structure, thus favoring the application as gas-sensitive materials. 相似文献
8.
Nanopowder of Y 1.84La 0.16O 3 was prepared by oxalate co-precipitation method. The powder was characterized by TG-DTA, XRD and TEM. The results show that the precursor is Re 2(NO 3) 2(C 2O 4) 2·2H 2O (Re=Y, La), and the Y 1.84La 0.16O 3 nanopowders produced by calcining the precursor at 1 000 ℃ for 4 h are 20~40 nm spherical particles and well dispersed. The powders were with high sintering activity and could be fabricated to transparent ceramic without additive at 1 450~1 550 ℃ in H 2 atmosphere for 3 hours. The total transmission of the transparent ceramic could reach 80%. 相似文献
9.
The precursor PbTi(OCH 2CH 3) 6-y(acac) y for the mixed oxide PbTiO 3was synthesized by electrochemical dissolution of Lead and Titanium with a 1∶2 electricity quality in ethanol and acetyl-acetone solution. Nano-sized PbTiO 3powder was prepared by drying and calcining the xerogel from a direct sol-gel hydrolyzation of the precursor solution under pH of 8.5. The FTIR, TG-DTA, XRD and TEM were employed to characterize the structure of the precursor and nano-sized PbTiO 3. The results showed that the optimized conditions for the preparation of nano-sized PbTiO 3 were the electrolysis of the Lead plate and Titanium plate at 50 ℃ and 40 ℃ respectively under 0.03mol·dm -3Bu 4NBr solution. The nano-sized PbTiO 3prepared by electrolysis exhibited a dispersive structure with an average diameter of 10 to 15 nm. 相似文献
10.
As a functional inorganic material, LiAlO 2 was focused on widely, especially in the field of tritium breeder of fusion reactor. In this article, the proper reaction conditions and mechanism to synthesis the γ-LiAlO 2 by solid state method are considered. In the experiments, it has been found that the phase of β- and γ-LiAlO 2 are only produced by the reaction of LiOH and Al 2O 3, while the α- and γ-LiAlO 2 can be obtained by the reaction of Li 2CO 3 and Al 2O 3. As compared with Li 2CO 3 and Al 2O 3 reacted at 900~1000℃ for the preparation of γ-LiAlO 2, the γ-LiAlO 2 can also be made by the reaction of LiOH and Al 2O 3 at some more lower temperatures that is due to the bulk diffuse mech-anism. But the former can get better crystal and have smaller particles for the mechanism of surface fast reaction. As a result, the sub-micron γ-LiAlO 2 powders with the diameter less than 0.3μm are obtained. 相似文献
11.
利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。 相似文献
13.
由于石化行业的生产需要,其材质的使用具有多样性和广泛性,经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识,根据光谱仪的测试能力及标样的采集,实现了一个或几个元素测量范围的扩展,并对其测量的影响因素进行了研究。 相似文献
14.
The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989. 相似文献
15.
The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted
indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator
model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was
established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing
analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom.
Translated from Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997. 相似文献
16.
The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness. 相似文献
17.
实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。 相似文献
18.
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins of Abies alba M., Larix decidua M., and Picea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins of Abies alba, Picea excelsa, and Picea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while in Larix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988. 相似文献
19.
Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases. 相似文献
20.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。 相似文献
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