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971.
合成了一系列磷酸和二元羧酸酯化交联改性的聚乙烯醇(PVA)膜,研究了它们用于水-乙醇混合液的渗透气化分离规律。磷酸改性的PVA膜具有较大的通量,当料液浓度为50%时,通量可达1200g/m~2·hr.,分离系数α_(H_2O/EtOH)=10。丙二酸改性PVA膜在料液浓度为50%时,通量可达800g/m~2·hr.,且α_(H_2O/EtOH)=18。并作了这两种膜的通量和分离系数随料液浓度的变化曲线。草酸交联的PVA膜具有较高的分离系数,但通量很小。求出了水、乙醇及总的表现渗透活化能。 相似文献
972.
A new fluorescent compound based on calix[4] arene skeleton was synthesized.Its complexation ability with transition metal ions,such as Fe^3 ,Co^2 ,Ni^2 ,Cu^2 ,Zn^2 and Ag^ ,Was investigated by UV-vis and fluorescent spectra. 相似文献
973.
An ordinary plating solution for indium hexacyanoferrate (InHCF) thin film deposition, mainly composed of equal concentrations
of In3+ and [Fe(CN)6]3–, usually forms precipitates rapidly when either concentration is higher than few millimolar. This contributes to the plating
solution's instability. Moreover, electrodeposited capacities are limited accordingly. In this work, the plating solution's
stability and the electrodeposition of InHCF were greatly enhanced by adding a large amount of K+ and/or H+. It was found that a 10-mM plating solution added with 1 M HCl and 1 M KCl could be stored as fresh over a one-week period,
whereas an unmodified plating solution became useless within a couple of minutes. Also, such cationic additions, especially
adding H+, increased the electrodeposited capacity ca. 18 times at least, as compared with that obtained from the unmodified plating
solution. Furthermore, related enhancing mechanisms were proposed and verified. To sum up, this study offers a means for better
InHCF electrodeposition and should promote the applications of InHCF films.
Electronic Publication 相似文献
974.
综述了1β-Methyl Carbapenem中间体的合成方法,重点强调了如何构筑1位β构型的甲基。参考文献37篇。 相似文献
975.
Comprehensive two-dimensional liquid chromatographic separation by means of a combination of ion-exchange chromatography (IEC)
and reversed-phase liquid chromatography (RPLC) has been realized and applied to the analysis of components of a traditional
Chinese medicine Flos Lonicera. In the first dimension the components of a Flos Lonicera extract is separated on strong anion-exchange (SAX) column according to the charge-exchange properties of the components.
In the second dimension the components are further fractionated by reversed-phase liquid chromatography (on ODS) on the basis
of their hydrophobicity. The RPLC effluent is desalted and split and the components are identified on-line by use of both
diode-array detection and mass spectrometry with atmospheric pressure chemical ionization (APCI–MS). In this way, the extract
of Flos Lonicera can be rapidly separated, desalted, and analyzed, with determination of molecular weight. More than 58 components of an extract
of Flos Lonicera were well resolved and six were tentatively identified from their UV and mass spectra. 相似文献
976.
Zhang YL Qin WW Liu WS Tan MY Tang N 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2002,58(10):2153-2157
An amide-based open-chain crown ether ligand and its complexes with europium and terbium were synthesized. The complexes were characterized by elemental analysis, infrared spectra and conductivity. The europium and terbium ions were found to coordinate to the C=O oxygen atoms and pyridine nitrogen atoms. The fluorescence properties of these complexes in DMF and CH3OH/CHCl3 were studied. Under the excitation of UV light, these complexes exhibit characteristic fluorescence of europium and terbium ions. The solvent factors influencing the fluorescent intensity are discussed. 相似文献
977.
978.
薯蓣皂甙元的分光光度法测定 总被引:41,自引:0,他引:41
本文以黄姜为主要对象研究了薯蓣皂甙元的定量测定方法,以香荚兰醛-高氯酸为显色剂,冰醋酸为溶剂,使皂甙元显色,用分光光度法在波长为530nm处测定薯蓣皂甙元的含量。从植物中提取的皂甙元不需分离可直接测定。在1.00~20.00mg/L范围内呈良好的线性关系。 相似文献
979.
980.
稀土对MoSi2力学性能和抗氧化性能的影响 总被引:2,自引:0,他引:2
采用自蔓延和真空烧结方法制备了掺杂0.9%La2O3的MoSi2基复合材料,利用热重分析法,SEM和X射线考察了La2O3颗粒对MoSi2力学性能、抗氧化特性以及循环氧化后力学性能的影响。结果表明,与纯MoSi2相比,RE/MoSi2材料的弯曲强度和断裂韧性分别提高了46%和78%;稀土对MoSi2材料的强韧化机制主要是细晶强化、弥散强化和细晶韧化。RE/MoSi2的氧化增重是纯MoSi2的2.5倍,稀土使MoSiz材料的抗氧化性能降低。由于纯MoSi2材料氧化后的晶粒长大,其抗弯强度比氧化前降低了17%。稀土对MoSi2氧化时的晶粒长大倾向有抑制作用,使得RE/MoSi2材料的抗弯强度基本不变。 相似文献