问题式教学在二组分金属相图的绘制实验中的应用

以Pb-Sn二组分金属相图的绘制实验为例,将问题式教学法应用于物理化学实验-二组分金属相图的绘制实验教学中。用预设问题引导学生,使学生在实验前对实验结果有了一定的预期,然后通过实验进行验证,让学生有的放矢地将理论与实践相结合,培养学生运用物理化学知识思考分析解决实际问题的能力,从而提高学生的学习主动性,也会促进教师主动学习,不断更新知识,并深入实际,在教学中做到游刃有余,实现教学相长。     

多元醇PG-TAM二元体系相图

多元醇在固-固相变时能够可逆地吸收大量的热而被用做贮热材料,特别是三羟甲基乙烷(PG)和三羟氨基甲烷(TAM)构成的二元体系,有很宽的适宜于太阳能贮存的温度范围。为了材料的选择,现利用差热分析(DTA)、X-射线衍射及变温红外光谱技术测定了PG-TAM二元体系相图。确定后的相图表明,从室温升温至熔化的过程中,相图在一定的组成范围内出现了三个低共熔点,分别为71℃、111℃和165℃。由于多元醇分子中存在-OH,因而多元醇分子间能形成氢键。随着温度的升高,多元醇发生固-固相变,分子间存在的氢键逐渐受到破坏,-OH伸缩振动的特征吸收波数向高波数发生突跃。变温红外光谱测得的-OH特征吸收峰位移发生突跃的温度区间恰好与体系各自DTA测得的相转变温度相吻合,多元醇的晶体结构、分子的大小是影响二元体系不同相态间互溶度的重要因素。     

TEAN-H_2O 二元体系的 TX 和 HX 相图

用ＤＳＣ研究了ＴＥＡＮ－Ｈ２Ｏ二元体系的低温热行为，建立了该体系的液化温度与组成关系的ＴＸ－二元相图和低共熔物表观熔融焓与组成关系的ＨＸ－二元相图。发现该二元体系是一个典型的具有简单低共熔物的二元体系，其低共熔温度为－１６．２℃，低共熔物组成为ＴＥＡＮ－Ｈ２Ｏ＝１０／９０（ｍｏｌ／ｍｏｌ）。过冷体系在升温过程中有结晶现象，其结晶焓与ＴＥＡＮ浓度有线性关系。ＴＥＡＮ浓度小于２５ｍｏｌ％时，具有玻璃化转变过程，其转变温度不随试样浓度的改变而变化，平均值为－９１．２℃，而在ＴＥＡＮ浓度大于２５ｍｏｌ℃时，未发现玻璃化转变。     

LiNO_3-KNO_3二元相图的热力学优化和计算

引入短程有序—扩展似化学模型来描述Li NO3-KNO3二元体系液相的Gibbs自由能,根据实验测定的相图数据,运用CALPHAD(Calculation of Phase Diagram)技术对该体系进行了热力学优化和计算,优化计算的结果和实测值符合很好。     

C语言在冷却塔热力计算中的应用

在冷却塔实验研究中,常有大量数据需要处理,计算量大。将Ｃ语言应用到冷却塔计算中,使冷却塔热力计算简化;并且利用Ｃ语言的数据文件操作对实验研究数据进行处理,提高工作效率。     

NiO-TiO_2二元系的热力学参数优化与相图计算

为获得与实验数据有较好自洽性的NiO-TiO2系相图,在评估NiO-TiO2系现有相图和热力学数据的基础上,采用CALPHAD技术进行了相图的优化计算,并对一些存在分歧的相进行了分析.对液相、NiO固溶体、Spinel相(尖晶石相)和NiTiO3,分别采用置换溶液模型和化合物能量模型进行处理,推导得到了一套自洽的,能够很好地拟合大部分实验相图和热力学数据的热力学参数.     

利用C语言程序进行卧式贮罐计量计算

通过用高等数学的方法推导出卧式贮罐的计量公式 ,利用C语言编制程序 ,将贮罐液位在各个位置时的体积通过列表的方式计算出来 ,使其计量更加简单明了。经过试验验证 ,公式可靠、运算正确 ,给实际生产操作过程中带来了很多方便。     

ZrO2-TiO2二元系的热力学参数优化与相图计算

为获得与实验数据有很好自洽性的ZrO-TiO2系相图,在评估ZrO2-TiO2系现有的相图和热力学数据的基础上采用CALPHAD技术进行了相图的优化计算,并对一些存在分歧的相进行了分析.对α-ZrO2,β-ZrO2 γ-ZrO2,β-(Zr,Ti)2O4,α-(Zr,Ti)2O4,ZrTi2O6,金红石型TiO2和液相分别采用了置换溶液模型以及化合物能量模型进行了处理.计算结果与相图的大部分最新的实验结果在误差范围内吻合较好.     

双液系气-液平衡相图的 Origin 绘制方法简

Origin是一款功能强大的专业数据分析与科技绘图软件。运用Origin软件对“双液系气一液平衡相图”的数据进行处理并绘图,可克服传统手工绘图费时费力的缺点,结果科学精确且方便快捷;与Excel软件所绘得的相图进行对比发现,Origin绘得的相图更为科学合理。物理化学实验教学中引入Origin软件的介绍,可提高学生使用计算机综合处理数据的能力,也为其日后的本科论文及科学研究工作奠定了基础。     

Phase Diagram of the BaO-CuO Binary System

The phase diagram of the BaO-CuO binary system has been investigated in air and in a mixed gas of Ar + 0.21 atm of O₂. The existence of two compounds, BaCuO₂ and Ba₂CuO₃, was confirmed. The phase transition of Ba₂CuO₃ from an orthorhombic to a tetragonal phase was observed to occur at 1083 K. The lattice constants of the tetragonal Ba₂CuO₃ phase were determined to be a = 1.2975 nm and b = 0.3992 nm. BaCuO₂ was shown to melt incongruently by a synthetic reaction at 1289 K. Furthermore, the existence of two eutectic reactions and a peritectic reaction in the present system was confirmed.     

密度泛函方法在物理化学二元相图教学中的应用

用量子化学密度泛函方法研究了两个完全互溶的二元体系水一乙醇和三氯甲烷一丙酮中同种和异种分子之间的相互作用,并应用计算所得的结合能数据判断了分子间相互作用的强度,揭示了这两个体系对理想液态混和物产生偏差的原因。研究结果表明：在水-乙醇体系中,异种分子之间的结合能小于同种分子之间的结合能,说明当乙醇和水混和时,体系总的作用力降低,挥发性增强,导致该溶液蒸气压对理想液态混合物产生正偏差。在三氯甲烷一丙酮二元体系中,相互作用的情况正好与水一乙醇体系相反,致使该溶液蒸气压对理想液态混合物产生负偏差,这些结果均与实验事实一致。     

Binary Phase Diagram of the Manganese Oxide–Iron Oxide System

The phase equilibrium of the MnO _x –FeO _y binary system was measured within a temperature range of 750°–1590°C in air to examine inconsistencies found in literature, i.e., discrepancies related to the boundary between the spinel and hausmannite+spinel phase fields. Several studies are available in the literature that describe this boundary however the results and methods by which they were studied vary namely in terms of the atmosphere (air versus reducing) used and heat treatment/analysis methods. In addition, samples in the discrepancy region of the diagram revert to the hausmannite phase spontaneously upon cooling due to a displacive transformation. In order to accurately measure the phase boundaries, the following measurement methods were used: isothermal heat treatments followed by rapid quenching (in air or water), dilatometry, differential thermal analysis with thermogravimetric analysis, as well as room temperature and hot-stage X-ray diffraction (XRD). Phase assemblage(s) in each specimen were determined by XRD. Data were compared with literature and a new, self consistent phase diagram was developed. The results are reported along with background information and a comparison with previously reported data. This study will support development of a model for thermodynamic equilibria in complex, multioxide silicate melts.     

二元系统相图的Flash制作

针对二元相图相关内容的教学特点,利用二维动画制作软件Flash制作了二元相图的课件。通过教学使用,取得了良好的效果。     

双液系气液平衡相图绘制实验的改进效果评价

结合本校在双液系气液平衡T-x相图绘制实验的改革,通过对以往文献分析和总结,评价了近年来该实验在体系选择、沸点仪的改进、待测样的配置技巧以及数据的自动化处理等方面取得的进展.该实验的每一处改进均体现出对相平衡理论的深刻理解以及实验室绿色环保意识的不断提高.     

二元液系气液平衡相图实验的改进

二元液系气液平衡相图实验是物理化学基础实验之一。在该实验中最困扰大家的是溶液的配制问题,因为只有合理地配制溶液才能使数据点在相图里分布合理。文章采用依次添加法配制溶液,优化了试剂的添加次序和添加量,使学生在有限的实验时间内得到更加完善的相图。     

High-Temperature Phase Diagram for the System Zr.

The melting, eutectic, peritectic, solidus, and liquidus temperatures in the system Zr-O have been measured directly by a simple optical pyrometric technique requiring only a few hundred milligrams of sample. The saturation solubility of oxygen in α-Zr( s ) between 1270° and 1980°C and the lower phase boundary of the ZrO₂–_α phase between 1900° and 2400°C have been measured by an isopiestic equilibration method. The oxygen solubility limit in α-Zr( s ) agrees well with previous low-temperature studies and reaches a maximum solubility of 35°1 at.% O at the eutectic temperature, 2065°°5°C. The maximum melting temperature of α-Zr( ss ) is 2130°°10°C and corresponds to a composition of 25°1 at.% O. Both of these temperatures are approximately 150° higher than previously reported. Liquidus compositions above the eutectic temperature were obtained via mass spectrometry from the kinetic behavior of the liquid solution-ZrO_2–x( s ) mixture as it approached equilibrium at 2125°°5°C. The lower phase boundary or solidus of the ZrO_2–x phase departs appreciably from ideal stoichiometry above 1900°C and smoothly reaches its most reduced composition, 61 at.% (ZrO_1.56), near 2300°C. The solidus is retrograde at higher temperatures. The melting temperature of the stoichiometric dioxide is 2710°°15°C.