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1.
用甘氨酸-硝酸盐燃烧合成法, 制备La xSr 1-xNi 1-yCo yO 3复合氧化物的陶瓷粉末, 对钙钛矿氧化物进行了XRD结构分析. 在通氧或不通氧下测试氧还原和氧析出的循环伏安曲线. 结果表明: 该氧电极具有双功能催化特性, 但不完全可逆. 利用汞灯作为激发光源, 进行几种水溶性染料和五种混合染料光解实验, 利用紫外-可见、红外以及人工神经网络光度法研究La xSr 1-xNi 1-yCo yO 3的催化性能. 结果表明: La xSr 1-xNi 1-yCo yO 3 ( x=0.7, 0.9, 1; y=0.3, 0.75)复合氧化物都具有较强光催化特性; La xSr 1-xNi 1-yCo yO 3的光催化活性高于La xSr 1-xNiO 3, 这与B位离子(Ni 2—, Co 2-)的电子构型有关; Co 2+的加入可使La xSr 1-xNiO 3的光催化活性有所提高. 相似文献
2.
采用高温固相法在空气中合成了Ba 1.97-yZn 1-xMg xSi 2O 7:0.03Eu, yCe 3+系列荧光粉。分别采用X-射线衍射和荧光光谱对所合成荧光粉的物相和发光性质进行了表征。在紫外光330~360 nm激发下,固溶体荧光粉Ba 1.97-yZn 1-xMg xSi 2O 7:0.03Eu的发射光谱在350~725 nm范围内呈现多谱峰发射,360和500 nm处有强的宽带发射属于Eu 2+离子的4 f65 d1-4 f7跃迁,590~725 nm红光区窄带谱源于Eu 3+的 5D0- 7FJ ( J=1,2,3,4)跃迁,这表明,在空气气氛中,部分Eu 3+在Ba 1.97-yZn 1-xMg xSi 2O 7基质中被还原成了Eu 2+;当 x=0.1时,荧光粉Ba 1.97Zn 0.9Mg 0.1Si 2O 7:0.03Eu的绿色发光最强,表明Eu 3+被还原成Eu 2+离子的程度最大。当共掺入Ce 3+离子后,形成Ba 1.97-yZn 0.9Mg 0.1Si 2O 7:0.03Eu, yCe 3+荧光粉体系,其发光随着Ce 3+离子浓度的增大由蓝绿区经白光区到达橙红区;发现名义组成为Ba 1.96Zn 0.9Mg 0.1Si 2O 7:0.01Ce 3+,0.03Eu的荧光粉的色坐标为(0.323,0.311),接近理想白光,是一种有潜在应用价值的白光荧光粉。讨论了稀土离子在Ba 2Zn 0.9Mg 0.1Si 2O 7基质中的能量传递与发光机理。 相似文献
3.
测定了三元系CeCl 3-CdCl 2-H 2O (25 ℃)和四元系CeCl 3-CdCl 2-HCl(~8.4%)-H 2O(25 ℃) 的相平衡溶度数据,绘制了相应的溶度图.该三元系是由5个固相区CdCl 2&;#8226;2.5H 2O(原始盐)、CdCl 2&;#8226;H 2O(原始盐)、6CdCl 2&;#8226;CeCl 3&;#8226;14H 2O、4CdCl 2&;#8226;CeCl 3&;#8226;12H 2O、CeCl 3&;#8226;7H 2O(原始盐)组成的复杂体系.该四元系是由5个固相区CdCl 2&;#8226;H 2O(原始盐)、9CdCl 2&;#8226;CeCl 3&;#8226;19H 2O、6CdCl 2&;#8226;CeCl 3&;#8226;14H 2O、4CdCl 2&;#8226;CeCl 3&;#8226;12H 2O、CeCl 3&;#8226;7H 2O(原始盐)组成的复杂体系.其中6CdCl 2&;#8226;CeCl 3&;#8226;14H 2O在该三元系是介稳化合物.9CdCl 2&;#8226;CeCl 3&;#8226;19H 2O 、6CdCl 2&;#8226;CeCl 3&;#8226;14H 2O和4CdCl 2&;#8226;CeCl 3&;#8226;12H 2O用X射线粉末衍射及TG-DTG和DSC等方法进行了研究,并对X射线粉末衍射进行了指标化. 相似文献
4.
用甘氨酸-硝酸盐燃烧合成法,制备La xSr 1-xFe 1-yCo yO 3复合氧化物的陶瓷粉末,对该钙钛矿型氧化物进行了XRD、IR、紫外漫反射光谱及循环伏安曲线分析。结果表明:该复合氧化物粉体平均晶粒为15.3~29.8 nm,为立方和正交晶系。该氧电极具有双功能催化特性,但不完全可逆。对水溶液染料进行光解实验,利用紫外-可见、人工神经网络光度法研究La xSr 1-xFe 1-yCo yO 3的催化性能。结果表明:CO 2+的加入可使La xSr 1-xFeO 3的光催化活性有所提高,B位离子(Fe 3+,CO 2+)改变与加入,使La xSr 1-xFe 1-yCo yO 3( x=0.7,0.3; y=0.3,0.9,1)光催化活性高于La xSr 1-xFeO 3。同时,对5种染料进行紫外光解,在0.75 h,脱色率大于91%,并为动力学一级反应。 相似文献
5.
在流动余辉装置上, 利用N 2空心阴极放电制备活性氮, 研究了活性氮与溴代烷烃(CHBr 3、CH 2Br 2、C 2H 5Br、C 4H 9Br) 反应的化学发光.上述所有反应中, 在550~750 nm波段均观察到了较强的NBr ( b1Σ+→X3Σ-)跃迁发射谱. 同时在活性氮与CHBr3和CH2Br2的反应中, 在流动管下游还观察到了CN (A2π, B2π→X2Σ+)的发射谱. 验证性的实验表明, 激发态NBr (b1Σ+)是由二步过程形成: N(4S)与溴代烷烃反应生成NBr (X3Σ-), 再通过N2 (A 3Σu+)分子能量转移到激发态NBr (b1Σ+); 而激发态的CN是通过N(4S) + CBr→CN(A, B) + Br过程形成的. 相似文献
6.
本文采用离子交换法分别制备了双复合锂锰氧化物Li 0.60[Mg xMn 1-x]O 2(0.05 ≤ x ≤ 0.15)和三复合锂锰氧化物Li 0.60[Mg xCo yMn 1-x-y]O 2( x=0.05,0.05 ≤ 相似文献
7.
报道了采用气相法对PbTiO 3陶瓷扩渗La-Ce混合稀土元素的研究. 在气相扩渗过程中, La, Ce与PbTiO 3陶瓷组元发生了复杂反应,生成了稀土化合物La 2Ti 6O 15和CeTi 21O 38, 制备出未见报道的La 2Ti 6O 15-CeTi 21O 38-PbTiO 3陶瓷材料, 经测试其导电性能发生了十分显著的变化. La 2Ti 6O 15-CeTi 21O 38-PbTiO 3陶瓷材料的室温电阻率从2.0 ×10 10 W·m下降为0.248 W·m,而且随着温度的变化, 晶粒电阻呈现明显的PTCR效应,而晶界电阻随着温度的升高,呈急剧连续降低状态,总电阻的变化规律与晶界电阻的变化相一致, 试样总电阻的PTCR效应已不存在, 近趋导体. 经XPS测试分析, 进一步证实了La 2Ti 6O 15-CeTi 21O 38-PbTiO 3陶瓷材料中铅、钛等元素均有变价, 因而导致了La 2Ti 6O 15-CeTi 21O 38-PbTiO 3陶瓷材料电阻率的降低, 测试结果还首次给出了La 2Ti 6O 15-CeTi 21O 38-PbTiO 3陶瓷材料中各元素结合能位置的峰值. TG-DTA热分析表明La 2Ti 6O 15-CeTi 21O 38-PbTiO 3陶瓷材料具有较好的高温热稳定性. 相似文献
8.
The luminescent properties of Pr 3+-doped LaB 3O 6, SrAl 12O 19, SrB 4O 7 and NaYF 4 in the vaccum ultraviol-et (VUV) range at different temperatures were investigated under the excitation of high-energetic synchrotron radiation. For Pr 3+ ions in LaB 3O 6, SrAl 12O 19 and SrB 4O 7, only the parity-forbidden 1S0→4 f2 transitions were observ-ed in the emission spectra at relatively low temperature; but the parity-allowed 4 f5 d→4 f2 transitions appeared simultaneously when the temperature was high enough. And the intensity of broad 4 f5 d→4 f2 emission increased relative to the intensity of 1S0→4 f2 emissions with increasing temperature. Then the thermal equilibrium model of energy levels was employed to the lowest 4 f5 d state and 1S0 state of Pr 3+ in the three hosts. The calculated curves were in good agreement with the experimental values, indicating the occurrence of the thermal excitation from 1S0 state to 4 f5 d states at high temperatures when the lowest 4 f5 d state lies higher than 1S0 state and the photon energy is high enough. 相似文献
9.
The precursor ZrW 1.6Mo 0.4O 7(OH) 2(H 2O) 2 was characterized by IR and XRD methods. δ′-ZrW 1.6Mo 0.4O 8 was prepared by careful controlling the annealing conditions from the precursor and was determined to have the formula as o-ZrW 1.6Mo 0.4O 8·H 2O by TG-DSC, IR, and XRD methods. The relation between o-ZrW 1.6Mo 0.4O 8·H 2O and o-ZrW 1.6Mo 0.4O 8 was discussed through variable temperature XRD patterns. Further more, the mechanism of the precursor dehydration was suggested. 相似文献
10.
测定了298.15 K下, 无液接电池Li-ISE│Li 2B 4O 7 (m A)(aq.), MgCl 2(m B)(aq.)│AgCl/Ag的电动势, 利用测定结果计算了Li 2B 4O 7-MgCl 2-H 2O体系离子强度在0.05~3 mol•kg -1范围内, 不同MgCl 2离子强度分数的溶液中LiCl的平均活度系数, 并给出了其随离子强度I, B 4O 72-和Mg 2+浓度的变化规律. 结合以往关于该体系和Li 2B 4O 7-LiCl-H 2O, Li 2B 4O 7-H 2O体系的等压研究结果, 用迭代和多元线性回归方法对Li +-Mg 2+-Cl --B 4O 72--H 2O体系的离子相互作用模型进行了研究. 具体方法为考虑了该体系在不同的总硼浓度范围H 3BO 3, B(OH) 4-, B 3O 3(OH) 4-和B 4O 5(OH) 42-四种含硼化合物的存在以及各硼化合物间的化学平衡, 以修正了的Pitzer渗透系数方程和活度系数方程为基础, 对该体系的等压法和电动势法研究结果进行最小二乘拟合, 拟合的标准偏差为0.0167, 用该模型计算的该体系的渗透系数、活度系数与实验值基本一致. 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
20.
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
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