Advance application of Raman spectroscopy for quantitative analysis of noncrystalline components in thin films of poly(ε-caprolactone)/poly(butadiene) blends

A quantitative analysis method for the distribution of noncrystalline poly(butadiene) component in poly(ε-caprolactone)/poly(butadiene) (PCL/PB) binary blends have been analyzed by advance application of Raman spectroscopy, optical microscopy, and differential scanning calorimetry (DSC) techniques. Thin films of different compositions of PCL/PB binary blends were prepared from solution and isothermally crystallized at a certain temperature. After calibration with real data, quantitative analyses by Raman spectroscopy revealed the amorphous PB are trapped inside the PCL crystals. Polarized optical microscopy and real time atomic force microscopy were used to collect data for the crystal morphology and crystal growth rate. For pure PCL crystals, a morphology of truncated lozenge shape was observed, independent of crystallization temperature and regardless of the blends compositions. For the pure PCL and their blends, almost unique crystal growth rate was found. The miscibility behaviors using DSC were drawn through melting point depression method. The Hoffman-Weeks extrapolations of the blends were found to be linear and identical with those of the neat PCL. The interaction parameter for the blends indicating that the PCL and PB blends have no intermolecular interaction, confirming the blends are immiscible. Despite the immiscibility of the blend, the PCL crystals do not bend during the growth process and do not reduce the growth rate as they do for miscible blend systems.     

Thermodynamic parameters of amitriptyline hydrochloride–additives at cloud point: effects of the ethanol–water mixed media

Abstract

Addition of organic solvents is known to change the properties of amphiphiles through modification of bulk phase. Amitriptyline hydrochloride (AMT) is a tricyclic amphiphilic drug which is usually used as an antidepressant. In drug delivery, the cloud point (CP) of the drug is an important parameter. This article discusses the effects of ethanol–water (EtOH–WR) compositions on the energetic parameters, such as changes in Gibbs energy of clouding (Δ_sG⁰), enthalpy of clouding (Δ_sH⁰), and entropy of clouding (TΔ_sS⁰) of AMT-additive systems. Monovalent alkali halide salts, cationic conventional surfactants, and gemini surfactants were used as additives in the EtOH–WR mixed media whose compositions were varied between 0 and 15% (w/w). The Δ_sG⁰ values are positive for all the additives and the values decrease with the rise in mole fractions of the additives. The Δ_sH⁰ and TΔ_sS⁰ were noted to be positive except for KF in 15% EtOH–WR mixed media.     

微波合成含氮掺杂碳量子点改性水性聚氨酯的制备与性能

以柠檬酸和尿素分别为碳源和氮源,微波法合成含氮掺杂碳点N-CDs。以异氟尔酮二异氰酸酯（IPDI）、聚氧化丙烯（PPG-2000）为主要原料,加入不同量的N-CDs制备一系列碳点水性聚氨酯复合材料 （N-CDs/WPU）。通过FTIR、TEM、XPS、UV-vis、荧光光谱和力学性能测试等对复合材料结构和性能进行表征。测试结果表明N-CDs主要由碳氮氧元素组成,表面具有胺基、羟基等活性基团,N-CDs的加入,提高了复合胶膜的力学性能,赋予了胶膜荧光性能。当N-CDs质量分数为0.6%时胶膜拉伸强度达到最大35.00MPa,加入量质量分数为0.8%时荧光强度最佳。     

Classification and identification of gas–liquid dispersion states in a jet bubbling reactor

Three gas–liquid dispersion states including flooding, loading, and complete dispersion are observed sequentially in a jet bubbling reactor with an increase of the liquid jet velocity at the nozzle outlet (u_j). The gas–liquid dispersion states are identified through the slope (k) of the curve of fluctuation distribution index (FI) versus u_j as follows: (a) under the flooding, k = 0; (b) under the loading, k > 0; (c) under the complete dispersion, k < 0. In particular, the u_j at the transition points from flooding to loading and from loading to complete dispersion are referred to flooding jet velocity (u_jf, the transition point between k = 0 and k > 0) and complete dispersion jet velocity (u_jcd, the transition point from k > 0 to k < 0), respectively. The average relative deviations of the u_j at the transition points obtained through the acoustic emission measurement and visual observation are less than 5%.     

采用GPS进行城市规划区送电线路测量的方法

本文介绍采用RTK GPS进行线路测量方法,分析影响直线精度因素及具体作业。     

GPS水准拟合优化法探讨

GPS水准拟合应用很广,其优化问题包括拟合模型的选取和拟合点数的确定以及拟合点的分布。文章应用沈云中教授提出的逐点剔除法分析了拟合点的选取过程和拟合点的最佳分布问题,最后以一实例并采用二次曲面作为拟合函数进行了具体优化分析,所得结论具有一定的参考价值。     

具有异状点的连续树映射

设f∈C°(T,T)是树T上的连续自映射,N为自然数集,则下述条件等价: 1)f有异状点; 2)f的拓扑熵大于零; 3)存在m∈N使得{mk:k∈N}(?)Per(f); 4)存在n∈N使得fn具有2-马蹄。     

二氧化铀芯块低温烧结机理的研究

基于PDM(point defect model),研究了UO2 x在微氧化性气氛下低温烧结的机理.理论讨论和试验验证了UO2低温烧结时铀离子的体扩散系数、低温烧结温度和致密化动力学方程.结果表明,在UO2中掺入多余氧可使铀离子的扩散激活能降低约3.0eV,铀离子的扩散激系数DUx∝x2,二氧化铀低温烧结的理论温度约为1089～1151℃,采用UO2 x坯块是实现低温烧结的必要条件.本模型理论计算的结果与试验数据符合较好,能很好地表征缺陷浓度随气氛变化的特点.     

低凝点柴油生产方案的研究

着重介绍了中国石油吉林石化公司低凝点柴油生产方案,通过产品质量跟踪、优化调合及使用降凝剂等一系列手段大幅度增产低凝点柴油,为炼厂增加产品竞争力,提高产品调合效益有很好的参考价值,同时简要介绍了炼油企业低凝点柴油进一步增产的方法和质量升级措施。     

计算脂肪醇沸点的新方法

直接从脂肪醇的分子结构提取4个结构参数:烷基的极化效应指数PEI、碳原子数目Nc、羟基所连接碳原子上的氢原子个数α-H和羟基与支链相对位置差ΔN,与118种脂肪醇的沸点进行相关分析,得到相关模型方程。运用留一法确证模型方程具有较好的稳定性和预测能力。方程所选用的参数计算简单,物理意义明确,能够被广泛使用。