Experimental studies on the effect of ultrasonic treatment and hydrogen donors on residual oil characteristics

Residual oil, the residue after the distillation of crude oil, imposes deleterious effects on refinery due to its high viscosity and asphaltene content. In this context, ultrasonic technology has been widely applied in refining processes given its high efficiency and minimal environmental impacts. To guide the selection of operation parameters, in this work, we probed the effect of treatment duration, power, and hydrogen donor on the characteristics of residual oil under ultrasonic treatments. Underlying mechanisms of ultrasonic treatments, in the absence and presence of hydrogen donors, were verified through systematically analyzing viscosity, component conversion, molecular weight, hydrogen distribution, and functional groups of residual oil. While viscosity reductions under low-power density treatment are caused by colloidal system disaggregation, high-power density treatment can bring in both chemical bond cleavage and colloidal system disaggregation. In addition, adding hydrogen donor can effectively prevent radical recombination, and thus increases the yield of saturate. These results provide fundamental understandings on the effects of ultrasonic treatments.     

顶空毛细管气相色谱法测定非那雄胺中有机溶剂的残留量

建立了顶空毛细管气相色谱法测定非那雄胺中二氯甲烷和氯仿两种有机溶剂残留量的方法,并讨论了平衡温度、平衡时间、盐效应对测定的影响。分析结果表明:该法可将两种残留有机溶剂完全分离,具有较好的线性(相关系数分别为0.999 7和0.999 8),检出限为3.2μg/L和0.094μg/L,测定结果的相对标准偏差分别为1.33%和0.89%,样品回收率分别为94%和96%。     

顶空气相色谱法测定烟用胶中残余单体

采用顶空气相色谱(HS-GC)法对卷烟用胶中甲基丙烯酸甲酯、甲基丙烯酸乙酯、甲基丙烯酸丁酯、丙烯酸甲酯、丙烯酸乙酯、丙烯酸丁酯和乙酸乙烯酯7种残余单体进行了分析。方法采用DB-VRX石英弹性毛细管色谱柱分离,氢火焰离子化检测器检测。7种单体能够完全分离,线性良好,线性相关系数在0.9985～0.9992之间,检测限在0.0030～0.0039mg/mL范围,相对标准偏差(RSD)小于1.92%。该方法操作简便、快速、高效、准确、灵敏度高,实用性强,可用于胶粘剂中残余单体的测定。     

Novel correlations between the critical constants of the noble gases

For any particular fluid, the set of three critical constants (CC) – pressure P_c, temperature T_c and molar volume V_c – has a central importance in defining the physical behaviour of the fluid in the gas and liquid states. However, little attention seems to have been paid in the past to the relations between the CC of different substances. In the present paper, some simple and apparently novel relations have been found between the three CC for the set of four noble gases: Ne, Ar, Kr, Xe. Defining the critical quotient Q_c ≡ RT_c/P_c (where R is the Gas Constant) the correlations may be summarised by the dual equation: (V_c/cm³ mol⁻¹) = 27 + 0.31 (T_c/K) = 3.3 + 0.280 (Q_c/cm³ mol⁻¹), which describes the CC data for the quartet Ne–Xe with an average uncertainty of 0.5%. Regarding the other two noble gases, the two isotopes of the lightest member, ³He and ⁴He, show the deviations from these relations that are expected from quantal effects and their low molar masses; while for the heaviest member, Rn, the correlations enable a value of 145(5) cm³ mol⁻¹ to be estimated for V_c that is not otherwise well defined in the literature. By contrast, and contrary to the general assumption, the second lightest member, Ne, apparently does not show appreciable quantal effects in the area, so that Ne–Xe may be considered together as a group. These correlations are compared with the behaviour of a selection of polyatomic fluids; in these comparisons, the NG dual correlation equation provides a reference line defining the presumed simplest behaviour. This and related areas show a “Residual Volume Effect”, in that extrapolating the equivalent temperature and energy parameters to zero for the state of zero-mass point particles, referred to here as the hypothetical element zeronium (Ze), the system in each case still has a finite intercept; this intercept amounts to essentially 34% of the average volume for the present quartet Ne–Xe, rather than the zero volume expected for this condition.     

An error-free algorithm to solve a linear system of polynomial equations

The paper presents an error-free algorithm to solve a system of linear equations with polynomial coefficients. Modular arithmetic in residual polynomial class and in residual numeric class is employed. The algorithm is iterative and well suited for implementation for computers with vector operations and fast and error-free convolutors.     

L2×L2中的一类无穷维Hamilton算子的剩余谱

该文得到了一类无穷维Hamilton算子的剩余谱和点谱存在的几个判别准则,从而给出 了求其剩余谱和点谱的方法．在此基础上构造了L2×L2中无穷维Hamilton算子的剩余谱 非空的具体例子,从而进一步验证了判别准则的有效性．     

具有第二次多选择服务的M[X]/G/1排队系统

本文研究成批到达的具有第二次多选择服务的单服务员排队系统．顾客的到达形成一广义泊松过程，不同批的顾客按先到先服务的规则，而同一批的顾客按随机次序接受服务．两次服务的服务时间都是一般分布且相互独立．本文采用补充变量法，求得在瞬态和稳态情况下系统队长的概率母函数，然后又计算出顾客的平均队长和平均等待时间．     

各向同性钢材的断裂模型和屈服模型

基于钢材断裂前必先屈服的基本事实, 以钢材断裂面为屈服面后继扩大直至材料完整性(连续性）发生破坏为假设, 以已有的屈服模型的共同特征为切入点, 建议了各向同性钢材在主应力空间的二次函数型断裂模型和屈服模型. 根据不同钢材的特征应力值, 量化了各向同性钢材的二次函数型断裂模型和屈服模型. 依据不同钢材的特征应力值的相互关系, 建议的各向同性钢材的二次函数型断裂模型和屈服模型相应地描述为主应力空间的圆柱面、椭球面、抛物面和双曲面. 建议的各向同性钢材的二次函数型断裂模型和屈服模型较已有的强度模型更具一般性.     

Residual stress/strain analysis in thin films by X-ray diffraction

Residual stresses are found in the majority of multilayer thin film structures used in modem technology. The measurement and modeling of such stress fields and the elucidation of their effects on structural reliability and device operation have been a “growth area” in the literature, with contributions from authors in various scientific and engineering disciplines.

In this article the measurement of the residual stresses in thin film structures with X-ray diffraction techniques is reviewed and the interpretation of such data and their relationship to mechanical reliability concerns are discussed.     

Elastic-plastic analyses on the residual stresses and curvature of the film/substrate bilayer system

During thermal cycling, the residual stresses are often generated in the film/substrate bilayer due to the material mismatch between the substrate and the film. If the thickness of the film is relatively high, the thermal residual stresses in it may be of different signs. When the film is subjected to elastic-plastic deformation, two plastic zones with different thicknesses may be generated in the film at a significantly high temperature difference. In this paper, a theoretical model which reflects the complete history of thermal residual stresses and curvatures in the elastoplastic film/substrate bilayer system is developed. Solutions are derived to estimate the residual stresses and curvature in the film as functions of temperature difference. The case of Al/Si system is used to illustrate the implementation of this model. Results show that the critical temperature difference at which the second plastic zone near the film surface is generated near the Al film surface is dependent on the film thickness. The strain hardening of the film has an obvious influence on the magnitude of residual stresses within the film at high temperature difference.