On occurrence of multiple-site crystallization in undercooled mullite melts

Using a high-speed video, an interesting multiple-site crystallization phenomenon in undercooled mullite oxide is observed in situ in an aero-acoustic levitation apparatus when a laser heating system is incorporated. This crystallization behavior is discussed considering nucleation theory and growth analysis by defining conditions under which multiple-site crystallization can occur.     

Electrochemical Reduction of Yttrium Ions

The cathodic electrode process of Y~(3+) ions on the Mo electrode in the LiCl-KCl molten salt withYCl_3(3wt%) in the temperature range of 450～530℃ has been investigated using cyclic voltammetry andchronopotentiometry.The convolution technique has been applied to the treatment of cyclic voltammogram.Theresults show that the reduction mechanism of Y~(3+) ion is Y~(3+)+3e=Y,a simple one-step process.The cathodicprocess is very close to a reversible process under lower scanning rates,and is diffusion-controlled.The cathodicproduct is an insoluble product.     

Acidic‐basic interactions in tungstate melts based on tungsten electroplating out of them

Based on thermodynamic calculations of possible reactions of interaction between sodium tungstate and oxygen‐containing compounds of boron, carbon, phosphor, sulphur, metals of VI‐B group the probability of possible reactions was evaluated. The experimental verification of the assumptions was accomplished by the methods of potentiometry and IR‐spectroscopy. The possibility of existence of equilibrium (reversible) melted systems with the electrodes from metals of VI‐B group and their carbides was proved by the electrochemical measurements and thermodynamic calculations.     

浅析文教建筑与环境的自然融合——以湖南师范大学专业教学楼建筑设计为例

现代文教建筑设计时应兼顾建筑与环境的共融共生。本文结合具体实例,从总平面设计构思、建筑单体设计、园林景观设计等方面详细阐述了现代高校教学综合楼建筑设计要点,并着重于建筑与环境方面分析探讨了现代文教建筑与环境的自然融合具体设计思路。     

氯化物熔体中铁离子的平衡及其应用

为了更好地了解镁电解中及熔盐氯化中铁的行为,对铁离子在氯化物中的化学平衡作了研究。求出在PCl₃=101.325kPa和实验温度下,反应FeCl_₂(熔)+1/2Cl₂(气)=FeCl₃(熔)的表观平衡常数K。在PCl₂=0和实验温度下,FeCl₃完全分解。K的测量值与回归方程的预报值很吻合。熔盐体系、氯分压和温度对K值影响较大,总铁浓度的影响稍小一些。在其他条件相同时,体系3的K值最大,这表明,用光卤石作为电解质时,镁电解的电流效率会低一些,而氯化钾含量高时,在熔盐氯化中铁的催化作用较好。     

Schichtbildung beim Feuerverzinken zwischen 435°C und 620°C in konventionellen Zink‐Schmelzen – eine ganzheitliche Darstellung

Layer formation by hot dip galvanizing between 435°C and 620°C in conventional zinc melts – a general presentation For four typical constructional steels with different Si‐content and enamelling steel the layer growth and the structure of the forming coats is examined as a function of the dipping duration, the melt temperature and the thermal pretreatment. The results are discussed with regard to the experimentally determined hydrogen effusion of the steel. For the temperature range from 435°C to 620°C a pattern is presented, which is applicable for the daily work in the normal and high temperature range.     

LiCl-KCl熔盐体系中Ce（Ⅲ）在液态Ga电极上的电化学行为

采用循环伏安法（CV）、方波伏安法（SWV）和计时电位法（CP）等暂态电化学方法研究了LiCl-KCl熔盐体系中Ce（Ⅲ）在液池Ga和液膜Ga电极上的电化学行为。以高纯Al₂O₃包覆的石墨棒作对电极，以Ag/AgCl(x=2%)为参比电极，结果表明，在液池Ga电极上，Ce（Ⅲ）可一步还原为αGa₆Ce：Ce（Ⅲ）+3e+6Ga=αGa₆Ce，该反应为不可逆过程，并受扩散控制；Ce（Ⅲ）的扩散系数与温度的关系式为：ln D=2.88-10 118.4/T；Ce（Ⅲ）/αGa₆Ce的半波电位与温度的关系式为：E=-1.701+5.472×10^-4T。此外，在Ga液膜电极上，Ce（Ⅲ）可发生欠电位沉积，形成至少三种金属间化合物。     

Calculating Model of Mass Action Concentrations for Mn-C Melts and Optimization of Thermodynamic Parameters

Based on the phase diagram, the coexistence theory of the metallic melt structure involving compoundformation and the regularity of melts containing saturated phase, a calculating model of mass action concentrationsfor Mn-C melts was formulated. According to the activities (or activity coefficients AM. and γc.), obtained by theUnified Interaction Parameter Model (UIPM), the thermodynamic parameters G and G at higher temperatures (1628～1873 K) were optimized by the repeated try and error method. It is testified that G G(873～1273 K) and G (298～1623 K), obtained at lower temperatures, can also be used at the above-mentionedhigher temperatures. The calculated N. and N agree well with ac. and ac obtained by UIPM. This result showsthat the deduced model can reflect the structural reality of Mn-C melts.     

铌硼酸盐玻璃熔体的高温红外光谱

本文首次采用高温红外光谱及DSC—7差热分析技术研究了Nb₂O₅—B₂O₃—K₂O系统玻璃熔体结构,并建立了该系统玻璃和高温熔体结构模型。