共查询到20条相似文献,搜索用时 171 毫秒
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黄姜是制取皂素和柠檬酸的原料。黄姜中微量金属元素的含量对制取皂素和柠檬酸的收率有明显影响,工艺过程对黄姜中微量元素含量有一定的要求范围。 对植物灰分中微量的分析,有用等离子体发射光谱分析,也有用原子吸收光谱法分析,我们则根据工艺要求,采用低压火花溶液干渣法同时测定黄姜灰分中Fe、Zn、 相似文献
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等离子发射光谱法测定钒铁中的铜、硅、铝、磷、铬、镍、钨、锰 总被引:2,自引:0,他引:2
叙述采用等离子发射光谱法同时测定钒铁中的铜、硅、铝、磷、铬、镍、钨、锰等微量元素 ,试样用稀王水分解 ,选择适当的波长与背景校正进行分析测定 ,方法回收率在 95%~ 1 0 5%之间 ,相对标准偏差均小于 4% ,本方法快速准确 ,精密度良好。 相似文献
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XRF法测定磷石膏中磷、铁、铝、硫、钾、钠、硅时,克服了传统法耗时长、劳动强度大、所用试剂多的缺点,操作简便,测定结果与传统法一致,准确度高,精密度好,能满足生产工艺控制、磷石膏综合利用等磷石膏分析的需要。 相似文献
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采用DUO-ICP-AES同时测定精对苯二甲酸中钴、铬、铁、锰、钼、镍、钛,并对仪器的分析线选择、背景校正、入射功率、雾化器压力、辅助气流量、冷却气流量、蠕动泵转速的影响及共存元素的干扰、硝酸铯灰化助剂等因素进行了详细的研究。方法的检测限:钴0.0097 mg/L;铬0.0021 mg/L;铁0.0078 mg/L;锰0.0012 mg/L;钼0.0027 mg/L;镍0.016 mg/L;钛0.0027 mg/L,回收率和精密度分别为93.0%~99.5%和0.37%~3.2%。该方法快速简便,具有良好的精密度和准确度,适用于进出口精对苯二甲酸的日常检验。 相似文献
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Densities and viscosities of the binary systems of sulfolane + ethylbenzene, sulfolane + p-xylene have been experimentally determined in temperature interval 303.15—353.15 K and at atmospheric pressure for the whole composition range. The excess molar volumes and viscosity deviations were computed. The computed quantities have been fitted to Redlich-Kister equation. Excess molar volumes and viscosity deviation show a systematic change with increasing temperature. Two mixtures exhibit negative excess volumes with a minimum which occurs approximately at χ = 0.5. The effect of the size, shape and interaction of components on excess molar volumes and viscosity deviations is discussed. 相似文献
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Experimental data on density and viscosity at 303.15 K and 323.15 K are presented for the binary mixtures of p-xylene with cyclohexane, n-heptane, n-octane, sulfolane, N-methyl-S-pyrrolidone and acetic acid. From these data, the excess molar volume and deviations in viscosity have been calculated. The computed quantities have been fitted to the Redlich-Kister Equation to derive coefficients and estimate the standard error values. Results are discussed in terms of intermolecular interactions. 相似文献
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Experimental data on density and viscosity at 303.15K and 323.15K are presented for the binary mixtures of p-xylene with cyclohexane, n-heptane, n-octane, sulfolane, N-methyl-2-pyrrolidone and acetic acid. From these data, the excess molar volume and deviations in viscosity have been calculated. The computed quantities have been fitted to the Redlich-Kister Equation to derive coefficients and estimate the standard error values. Results are discussed in terms of intermolecular interactions. 相似文献
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Jareena Shaik Manukonda Gowri Sankar Dittakavi Ramachandran Chintala Rambabu 《Korean Journal of Chemical Engineering》2014,31(8):1460-1469
Experimental values of the density and viscosity have been measured for binary mixtures of N-ethylaniline with isomeric butanols (1-butanol, 2-butanol, 2-methyl-1-propanol and 2-methyl-2-propanol) at 303.15, 308.15 and 313.15 K over the entire mole fraction range. These data, the excess molar volumes, and deviation viscosity for the binary systems at the above-mentioned temperatures were calculated and fitted to Redlich-Kister equation to determine the fitting parameters and the root-mean-square deviations. The excess molar volumes, deviation viscosity and excess Gibbs energy of activation of viscous flow have been analyzed in terms of acid-base interactions, hydrogen bond, and dipole-dipole interaction between unlike molecules. The results obtained for dynamic viscosity of binary mixtures were used to test the semi-empirical relations of Grunberg-Nissan, Katti-Chaudhri, and Hind et al. equations. 相似文献
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巴豆酸乙酯与乙醇混合液密度和粘度的测定及关联 总被引:2,自引:0,他引:2
主要介绍了3-羟基丁酸乙酯合成过程中的相关物系的物性测定.在常压下采用U形振动管密度计测定了巴豆酸乙酯与乙醇的混合液在293.15~343.15 K下的密度,用乌氏粘度计测定了此混合溶液在293.15~343.15 K下的粘度,并由密度数据计算出超额体积V E、由粘度数据计算出了不同温度和组成下的混合粘度的变化Δη,V E和Δη这些值均为负值.同时对不同温度下的超额体积与组成的关系,粘度变化与组成的关系分别用Redlich-Kister方程进行了关联,最大标准偏差小于5%;说明此方程可适用于回归两相体系中上述的物性数据. 相似文献
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在常压下采用U形振动管密度计测定了碳酸二甲酯-甲醇的混合液在293.15~323.15K和碳酸二甲酯-氯苯的混和液在293.15~343.15K下的密度;用乌氏粘度计测定了这两个混合溶液在相应温度下的粘度,并由密度数据计算出超额体积V^E、由粘度数据计算出了不同温度和组成下的混合粘度的变化Δη,前者V^E、Δη均为负值。后者V^E为正值,Δη基本聚集在0附近。对不同温度下的超额体积、混合粘度变化与组成的关系按Redlich-Kister方程进行了关联,最大标准偏差小于5%;说明这两体系适合采用此方程回归。 相似文献
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Alejandro Estrada-Baltazar Micael Gerardo Bravo-Sanchez Gustavo Arturo Iglesias-Silva Juan Francisco Javier Alvarado Edgar Omar Castrejon-Gonzalez Mariana Ramos-Estrada 《中国化学工程学报》2015,23(3):559-571
Densities (ρ) and dynamic viscosities (η) for three binary mixtures of n-decane with 1-pentanol, 1-hexanol and 1-heptanol are presented at temperatures from 293.15 to 363.15 K and atmospheric pressure over the entire composition range. The density and viscosity are measured using a vibrating tube densimeter and a cylindrical Couette type rotating viscometer, respectively. Excess molar volumes (VE), viscosity deviations (Δη) and excess Gibbs energy of activation of viscous flow (ΔG*E) are calculated from the experimental measurements. Intermo-lecular and structural interactions are indicated by the sign and magnitude of these properties. Partial molar vol-umes and infinity dilution molar partial volumes are also calculated for each binary system. These results are correlated using Redlich–Kister type equations. 相似文献
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常压下测定了乙酸乙酯和1,2-丙二醇二元系在298.15~323.15 K下的密度、折射率和黏度,建立了混合液密度、黏度随组成和温度变化关系的方程。计算了过量摩尔体积VE,折射率偏差ΔnD,黏度偏差Δη和过量流动活化自由能ΔG*E。结果表明,过量摩尔体积低温时在全浓度范围内为负值,但随温度升高,在富酯区变为正值;而折射率偏差高温时在富醇区为微小正值,其他情况都是负值;黏度偏差和过量流动活化自由能显示了相同的变化关系,均为负值,且都随温度降低而偏差增大。 相似文献