Image-plane measurements of coexistence curve diameters

The diameter of the coexistence curve has been measured for several fluids to determine differences from linear form. The experimental method consists of optical interference measurements in a Mach-Zehnder interferometer supplemented by measurements of deviation in a hollow prism. The fluid sample is contained in a temperature-stabilized cell in one branch of the interferometer. A variation in cell temperature causes the density profile within the cell to change, resulting in a change of the interference pattern, which is monitored photographically. From the relation of this pattern at any temperature to the pattern at the critical temperature, information on the refractive indices of the liquid and vapor phases is obtained. This information is combined with measurements of the Lorentz-Lorenz coefficient to obtain liquid and vapor densities along the coexistence curve. The average of liquid and vapor densities is analyzed in terms of RG theory. The results of the experiment yield information on three body interactions. Studies have been completed on ethane, ethylene, hydrogen, and fluoroform.Paper presented at the Tenth Symposium on Thermophysical Properties, June 20–23, 1988, Gaithersburg, Maryland, U.S.A.     

在ZSM－5分子筛上引入Zn、Ga物种对乙烷芳构化的影响

报道了在Ｚｎ、Ｇａ改性的ＺＳＭ－５分子筛上进行乙烷芳构化与乙烯芳构化反应的结果，并考察了反应温度对Ｚｎ－ＺＳＭ－５催化剂乙烷芳构化性能的影响和催化剂Ｇａ－ＺＳＭ－５的焙烧时间对其性能的影响等。试验结果表明：（１）乙烷脱氢活化步骤是乙烷芳构化反应的控制步骤，Ｚｎ、Ｇａ物种对乙烷脱氢活化起着至关重要的作用，并且ｚｎ物种的作用大于Ｇａ物种。Ｚｎ、Ｇａ物种还能促进聚合环化物脱氢向芳烃转化：（２）升高反应温度对乙烷脱氢活化和聚合环化物脱氢有利，同时会使聚合环化物的裂解反应速度增加，因而在乙烷芳构化反应中存在最佳温度；（３）延长焙烧时间，有利于乙烷的活化及乙烯、Ｃ＿３等芳构化中间产物向芳烃的转化。     

内燃机用阻燃型空气过滤纸的研制

实验探讨了以十溴二苯乙烷为主体的溴-锑协同阻燃体系中溴-锑元素质量比对空气过滤纸阻燃效果的影响,结果表明,二者最适质量比为3∶1。在此比例下,进一步研究了阻燃剂用量对空气过滤纸阻燃性能、力学性能以及透气性的影响,结果显示,阻燃剂留着率为25%时,阻燃性能达到GB/T14656—1993要求,此时挺度提高了约20%,但耐破度和透气度分别下降了约11%和10%。     

基于TDLAS技术1.65μm附近乙烷分子高分辨吸收光谱测量

基于可调谐半导体激光光谱(TDLAS)技术,结合实验室自制程长可达50 m的Herriot池,使用波长计对乙烷吸收谱线进行了准确定标,并根据记录的光谱数据,精确测量了6039～6054 cm-1波段内71条乙烷分子的谱线(中心位置及谱线强度),最小可探测谱线吸收强度为10-25 cm-1/(molecule·cm-2),对结果及误差进行了详细分析,为进一步研究天然气提供了重要参考.     

PEG/增塑剂共混物相容性的分子动力学模拟和介观模拟

为解决含能钝感增塑剂应用于硝酸酯增塑聚醚(NEPE)推进剂的问题,研究了增塑剂三羟甲基乙烷三硝酸酯(TMETN)、硝化甘油(NG)、1,2,4-丁三醇三硝酸酯(BTTN)与粘合剂预聚物聚乙二醇(PEG)的相容性。采用分子动力学模拟计算了PEG、TMETN、NG、BTTN四种纯物质的溶度参数及分子内和分子间径向分布函数,得到相容性优劣顺序为:TMETN/PEGBTTN/PEGNG/PEG。BTTN分子中的亚甲基和TMETN的结构削弱了自身分子间作用、降低了与PEG溶度参数的差值;分析了共混物的结合能及分子间径向分布函数,认为增塑剂与PEG相容的本质为"分子间以非键作用相结合,范德华作用占主要比重"。此外,增塑剂与PEG分子的极性越相近、范德华作用的占比越大;通过介观模拟得到体系的介观形态演变过程,发现NG/PEG及BTTN/PEG易发生相分离、TMETN/PEG仅发生轻微的同相归并。最终得出:含能钝感增塑剂TMETN与PEG的相容性优于BTTN及NG,可以考虑将其代替或部分代替NG、降低NEPE推进剂的感度,为低易损战术武器的发展提供依据。     

评价白酒质量优劣的两项重要指标

评价白酒质量的优劣,最直观的两个指标是杂醇油和高级脂肪酸乙酯。适量杂醇油和高级脂肪酸乙酯是构成白酒香味成分不可缺少的呈味物质,也因其贮存过程中相对稳定性及在分析过程中分离度高、定量准确等特点,可以作为评价白酒酒质优劣的两项重要指标。     

A comparative study of Ni catalysts supported on Al2O3, MgO–CaO–Al2O3 and La2O3–Al2O3 for the dry reforming of ethane

CO₂ utilization through the activation of ethane, the second largest component of natural and shale gas, to produce syngas, has garnered significant attention in recent years. This work provides a comparative study of Ni catalysts supported on alumina, alumina modified with CaO and MgO, as well as alumina modified with La₂O₃ for the reaction of dry ethane reforming. The calcined, reduced and spent catalysts were characterized employing XRD, N₂ physisorption, H₂-TPR, CO₂-TPD, TEM, XPS and TPO. The modification of the alumina support with alkaline earth oxides (MgO and CaO) and lanthanide oxides (La₂O₃), as promoters, is found to improve the dispersion of Ni, enhance the catalyst's basicity and metal-support interaction, as well as influence the nature of carbon deposition. The Ni catalyst supported on modified alumina with La₂O₃ exhibits a relatively stable syngas yield during 8 h of operation, while H₂ and CO yields decrease substantially for Ni/Al₂O₃.     

预测乙烷/离子液体系统溶解平衡的UNIFAC模型

采用UNIFAC模型对乙烷在1-烷基-3-甲基咪唑双三氟甲基磺酰亚胺盐([RMIm][Tf2N],R=乙基(E)、丁基、己基、辛基(O)、癸基)离子液体中的113个溶解度数据进行关联,得到了乙烷与主基团CH2—和[MIm][Tf2N]间的交互参数,建立了预测乙烷在该类离子液体中溶解度的UNIFAC模型。利用该模型预测了乙烷在[EMIm][Tf2N]和[OMIm][Tf2N]两种离子液体中的溶解度,预测值与文献值吻合较好,平均误差分别为4.01%和3.81%,最大误差为9.86%。将该模型用于分析改变烷基链长对乙烷在[RMIm][Tf2N]离子液体中溶解度的影响发现,在烷基链长较短时,增加其链长可有效提高乙烷的溶解度;但当烷基链长较长时,其效果减弱。该模型可对乙烷在该类离子液体中的溶解度进行有效预测,为其相关的传质分离过程提供相平衡数据。     

Photocatalytic conversion of ethane: status and perspective

Ethane (C₂H₆) is a main component of natural gas and a notable contributor to photochemical pollution and ozone production in the atmosphere. It is important to convert ethane to useful chemicals. The photocatalytic conversion of ethane is promising but challenging. As the first review article in this area, we summarize the recent important progresses in photocatalytic ethane conversion, with an emphasis on (1) homogeneously functionalization and (2) heterogeneously partial oxidation of ethane. Furthermore, the challenges and future directions are provided for the photocatalytic conversion of ethane.     

Low‐Temperature and Rapid Growth of Large Single‐Crystalline Graphene with Ethane

Future applications of graphene rely highly on the production of large‐area high‐quality graphene, especially large single‐crystalline graphene, due to the reduction of defects caused by grain boundaries. However, current large single‐crystalline graphene growing methodologies are suffering from low growth rate and as a result, industrial graphene production is always confronted by high energy consumption, which is primarily caused by high growth temperature and long growth time. Herein, a new growth condition achieved via ethane being the carbon feedstock to achieve low‐temperature yet rapid growth of large single‐crystalline graphene is reported. Ethane condition gives a growth rate about four times faster than methane, achieving about 420 µm min^?1 for the growth of sub‐centimeter graphene single crystals at temperature about 1000 °C. In addition, the temperature threshold to obtain graphene using ethane can be reduced to 750 °C, lower than the general growth temperature threshold (about 1000 °C) with methane on copper foil. Meanwhile ethane always keeps higher graphene growth rate than methane under the same growth temperature. This study demonstrates that ethane is indeed a potential carbon source for efficient growth of large single‐crystalline graphene, thus paves the way for graphene in high‐end electronical and optoelectronical applications.