共查询到20条相似文献,搜索用时 140 毫秒
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本文用模式识别-人工神经网络结合化学键参数法,总结熔盐电导的半经验规律,在此基础上讨论了熔盐电导的主要影响因素及电导机理。 相似文献
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本文借助于DTA和X射线结构分析测定了LaCl3-SrCl2-MgCl2三元体系相图,发现它属简单低共熔型,体系内有对应于LaCl3,SrCl2和MgCl2的3个液相面、3条2次结晶线和1个三元低共熔点E(15.0wt%LaCl3,49.5wt%SrCl2,35.5wt%MgCl2;545℃),并且在固相下有一个不稳定的化合物生成,在约500℃时分解。 相似文献
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钇离子在氟化物体系中的电化学还原 总被引:1,自引:0,他引:1
用循环伏安法和卷积伏安法研究钇离子在LiF-NaF-YF_3熔融盐中的阴极还原过程。结果表明,在实验条件下钇离子的电化学反应为一步还原,阴极过程受扩散控制,产物钇与铂形成合金。 相似文献
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用Monte Carlo方法对La-LaCl_3-KC1体系在1223K时的结构进行了计算机模拟研究,得到了熔体中诸离子对的偏径向分布函数和体系在1223K的势能和内能。结果表明,在熔体中La(Ⅲ)有相当一部分以LaCl_6~3六配位形式存在,而La(Ⅱ)则主要以LaCl_4~2四配位形式存在。结果还表明,熔体中的自由体积分布不均匀,存在许多不规则的空孔和缝隙,其中XK~+·YC1~-集团内的缝隙比纯KC1熔体中的缝隙明显增多。 相似文献
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针对镧系元素钕,本文通过循环伏安、开路计时电位、方波伏安等方法研究了773 K时Nd(Ⅲ)在钼电极上在LiCl-KCl-ZnCl2熔盐体系中的电化学行为及Zn-Nd合金的形成过程. 结果表明:在LiCl-KCl-ZnCl2熔盐中,Nd(Ⅲ)在预先沉积的Zn 阴极上欠电位沉积形成三种Zn-Nd金属间化合物. 基于电化学行为研究,采用恒电位电解提取Nd并用方波伏安曲线测量来检测Nd(Ⅲ)离子浓度的变化,然后通过电解前后Nd(Ⅲ)离子浓度变化评估了Nd的电解提取效率. 实验结果表明:-1.84 V恒电位电解进行50 h后,Nd(Ⅲ)离子浓度接近于零,提取效率为99.67%. 在973 K时通过恒电流电解提取Nd并获得了Zn-Nd合金,通过X射线衍射(XRD)和扫描电子显微镜(SEM)附带能量散射谱(EDS)对合金的相组成和微观形貌进行了分析. XRD分析表明在Zn-Nd合金中存在Nd2Zn17,LiZn 和Zn相,EDS能谱分析表明Nd在合金中的原子分数高达14.99%. 相似文献
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The effect of molecular weight on the polymorphic transformation of isotactic poly(1-butene)(iPB) under room temperature had been investigated by fourier transform infrared spectroscopy(FT-IR). The phase transformation time, phase transformation rate and phase transformation time difference between phase I and phase II at a given transformation degree were used to analysis the phase transformation kinetics of iPB aging at room temperature. The results show that the reduction of phase II can occur quickly at room temperature and seem less dependent on the molecular weight. However, the molecular weight has great effect on the formation of phase I. When the phase transformation degree for phase I reach 90%, a distinct transformation time difference can be observed. In order to clearly explain the difference in the reduction of phase II and the growth of phase I, a phase transformation model from the chain conformation level for iPB with different molecular weight have been drawn. DSC analysis was used to support the proposed model. 相似文献
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在基于相位分析的三维测量系统中,为了准确地得到物体的高度,相位展开扮演着很重要的角色。传统的相位展开方法常常需要额外的投影图,而傅里叶变换轮廓术只需要采集一幅或两幅变形条纹图就可以实现对物体轮廓的测量,其方法速度快,易于实现。针对傅里叶变换轮廓术方法计算得到的截断相位分布,本文提出了一种利用截断相位与参考平面相位差值2π的整数倍数获得截断相位的正确级次,辅助相位展开的方法。当被测物体较复杂,或者相位截断次数较多时,该方法在已有参考平面相位的基础上虚拟新的相位平面,依次比较截断相位和虚拟相位,进行多次分级相位展开,结合多个展开相位结果,最终得到正确的展开相位。该方法展开速度快,展开错误不会蔓延传递。仿真和实物实验结果证明了该方法的可行性,说明该方法可用于傅里叶变换轮廓术中进行截断相位的快速展开。 相似文献
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This paper discusses the behaviour of angiotensin 1 and neurotensin together with their metabolites in a three-phase liquid phase microextraction under acidic conditions. Variations in donor phase, organic phase, and acceptor phase are studied with extraction recovery as response variable. It is proved that for all peptides the transport across the organic phase is mediated by heptane-1-sulphonic acid. n-Octanol gave overall best results as organic phase. A donor phase volume of 1.0 mL was chosen as a compromise between optimal recovery and robustness of the LPME device. The optimal pH of the donor phase (using acceptor phase of pH 2) was found to be different for the peptides, which opens opportunities for selective sample preparation. Decreasing the acceptor phase pH to 1.0 resulted in increased extraction recoveries. On using 1.0 mL of donor phase containing 50 mM heptane-1-sulphonic acid pH 3, n-octanol as organic phase immobilized in the pores of the fibre, and 20 microL of acceptor phase containing 0.1 mol/L HCl, extraction recoveries up to 82% (enrichment factor = 41) were achieved. To our knowledge this is the first report on liquid phase microextraction of angiotensins and neurotensins. 相似文献
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Masashi Haruki Kazuhiko MatsuuraYuichi Kaida Shin-ichi KiharaShigeki Takishima 《Fluid Phase Equilibria》2010
The microscopic phase behavior of the supercritical carbon dioxide (scCO2) + polyethylene oxide-2,6,8-trimethyl-4-nonyl ether (TMN) + water systems at about 3 wt% of TMN were investigated using a synthetic method with a microscope. The two types of TMN (TMN-3 and TMN-10) used in this work had molecular weight distributions caused by the distribution of the number of ethylene oxide groups. Two different types of phase transition were observed when pressure was decreased gradually at a constant temperature from the high pressure at which the transparent phase was observed to the low pressure at which the separate vapor–liquid phases were observed for the scCO2 + TMN-3 + water system at 3 wt% of TMN-3. The transparent phase was colorless under all experimental conditions and the phase transition from a transparent phase to a turbidity phase with small, dispersed droplets was observed at the higher side phase transition (higher phase transition pressure). As the pressure continued to decrease, another phase transition was observed from the phase with small droplets to a state with an accelerating aggregation of droplets (lower phase transition pressure). In the turbidity phase between the higher and the lower phase transition, the degree of turbidity became higher with decreasing pressure. On the other hand, in the phase observed below the lower phase transition, a new liquid phase adhered to the sapphire windows and the wall inside the optical cell. 相似文献
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Three-phase separation for Triton X-114 or Triton X-100 solutions with addition of hydrophobically modified hydroxyethyl cellulose was investigated experimentally. When the surfactant concentration was high enough, the solution slightly above the cloud point could separate into three macroscopic phases: a cloudy phase in between a clear phase and a bluish, translucent phase. The rate of phase separation was very low with the formation of the clear and cloudy phases followed by the emergence of the bluish phase. The volume fraction of the cloudy phase increases linearly with the global polymer concentration, whereas the volume fraction of the bluish phase increases linearly with the global surfactant concentration. Composition analyses found that most of the polymer stayed in the cloudy phase, as opposed to most of the surfactant in the bluish phase. The interesting phase behavior can be explained by an initial associative phase separation followed by a segregative phase separation in the cloudy phase. 相似文献
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The formation of lyotropic mesophases (liquid crystals) in four binary systems n-alkyl glycosides/water was examined in dependence on surfactant concentration, temperature and the chain lengths (alkyl = heptyl, octyl, nonyl, decyl). The binary phase diagrams were established and the enthalpies of phase transitions were measured. The following phase transitions were detected by texture observation and calorimetry: hexagonal phase H, lamellar phase L, cubic phase Q, gel phase G and crystalline phase C. The positions of the corresponding regions of these phases in the phase diagram were determined. Sequence of phases and the localization of the phase regions were depended on the chain length of the alkyl group. So in the binary system n-decyl-β-D-glucoside/water the H-phase was not observed. 相似文献
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Summary The chromatographic properties of an alkylphosphonate-modified magnesia-zirconia composite stationary phase have been investigated
by reversed-phase high-performance liquid chromatography with basic compounds as probes. The influence of organic modifier
composition and mobile phase pH was studied. The new stationary phase, similar to a silica-based reversed-phase stationary
phase, has hydrophobic properties, but greater pH stability. Use of the phase results in more symmetric peaks for basic compounds.
A possible mechanism of retention of basic solutes on the new stationary phase is discussed. The chromatographic behavior
of the basic solutes depends mainly on hydrophobic interactions between the solutes and the hydrophobic moiety of the stationary
phase. Br?nsted acidic and basic sites on the surface of the new stationary phase play an important role in the retention
of ionized solutes by ion-exchange interaction. Promising separations of some basic compounds have been achieved by use of
methanolic TRIS buffer, pH 10.0, as the mobile phase. 相似文献