Solubility and metastable zone width measurement of 2,4-diaminobenzenesulfonic acid in (H2SO4 + H2O) system

The equilibrium solubility of 2,4-diaminobenzenesulfonic acid and super solubility as well as metastable zone width were measured in (H₂SO₄ + H₂O) system by the laser dynamic method at elevate temperature range from 298.15 K to 338.15 K. 2,4-Diaminobenzenesulfonic acid solubility dependence on the temperature and solvent composition were correlated by the modified Apelblat equation, (CNIBS)/Redlich-Kister model and Jouyban-Acree model. The correlated results by three correlation models were in good accord with the experimental values according to relative average deviations (RD), root-mean-square deviations (RMSD), and correlation coefficients (R²). The metastable zone width increased with temperature and sulfuric acid content. The dissolution enthalpy, dissolution entropy and the Gibbs energy were calculated from the experimental values, which indicated that dissolution process of the 2,4-diaminobenzenesulfonic acid was endothermic. The solubility and calculation models of 2,4-diaminobenzenesulfonic acid in (sulfuric acid + water) system could provide the basic data to the crystallization and purifying of the 2,4-diaminobenzenesulfonic acid.     

Mechanism analysis of solvent selectivity and energy-saving optimization in vapor recompression-assisted extractive distillation for separation of binary azeotrope

Octane and p-xylene are common components in crude gasoline, so their separation process is very important in petroleum industry. The azeotrope and near azeotrope are often separated by extractive distillation in industry, which can realize the recovery and utilization of resources. In this work, the vapor–liquid equilibrium experiment was used to obtain the vapor–liquid equilibrium properties of the difficult separation system, and on this basis, the solvent extraction mechanism was studied. The mechanism of solvent separation plays a guiding role in selecting suitable solvents for industrial separation. The interaction energy, bond length and charge density distribution of p-xylene with solvent are calculated by quantum chemistry method. The quantum chemistry calculation results and experiment results showed that N-formylmorpholine is the best solvent among the alternative solvents in the work. This work provides an effective and complete solvent screening process from phase equilibrium experiments to quantum chemical calculation. An extractive distillation simulation process with N-formylmorpholine as solvent is designed to separate octane and p-xylene. In addition, the feasibility and effectiveness of the intensified vapor recompression assisted extraction distillation are also discussed. In the extractive distillation process, the vapor recompression-assisted extraction distillation process is globally optimal. Compared with basic process, the total annual cost can be reduced by 43.2%. This study provides theoretical guidance for extractive distillation separation technology and solvent selection.     

治疗兔耳增生性瘢痕的研究进展

人体皮肤组织在受到损伤后,如烧伤、手术、外伤等,必然会引起外观和组织学的改变,伤口损伤愈合后形成瘢痕.瘢痕给患者带来局部不适感,导致功能障碍,大大地影响正常生活.兔耳增生性瘢痕在组织学上已被证实与人类增生性瘢痕相似,其获取成本低,并可动态观察瘢痕发展演变的全过程.从而可以加以药物干预,运用生化等检测结果,评估多种治疗方...     

变角绝对测量镜面红外反射比光学附件设计原理

在会聚光学系统中,改变反射镜面入射角会引起焦点位置及方向的变化。本文在红外傅里叶变换光谱仪测量系统中提出一种新附件设计原理,通过两块反射镜的变化,使其焦点固定在某一位置上实现变角测量。     

用GOSA软件优化设计绝对反射比测量光学系统

GOSA软件包具有很强功能,本文介绍了采用该系统软件,对变角测量的光学系统进行了优化设计和评估。     

刀具破损实时监控系统

刀具监测是自动化加工过程控制与优化的重要组成部分.本文研究了刀具破损过程中声发射信号的时域与频域特征,介绍了利用声发射原理研制开发的刀具破损实时监控仪AEM-2000的硬件组成及工作原理.     

圆柱齿轮啮合过程齿根应力数值计算方法研究

本文提出了一套在微机上计算机直齿与斜齿圆柱齿轮啮合过程齿根应力分布的方法。使用者只需输入一对齿轮副的几何参数和结构参数，计算机将自动完成齿轮副的三维有限无风格部分。通过齿面坐标系及坐标变换矩阵，一次求出核齿轮副的齿向载荷分布齿间载荷分本。一步运用 齿根局部网络密化，可详细研究轮在啮合过程中的齿根应力分布。编制的软件配有较强的数据前，后处理手段，便于使用。文中以一对斜齿轮副为例进行了说明，计算结果与     

SPS型复合加脂剂的应用

SPS 型复合加脂剂与铬鞣革的结合能力较强,是矿物鞣革的反应型加脂剂,本文介绍了 SPS 型复合加脂剂在猪正面服装革、山羊服装革加脂上的应用及加脂革的物理化学性能。     

E_2系统极限环线(3,1)分布参数区间的扩大

本文对一类 E_2系统进行了研究,在保证极限环线(3,1)分布的情况下,扩大了参数 n 的变化区间,在较弱条件下给出了该系统具有极限环线(3,1)分布的一个充分性条件。     

北方冬季输送成品油管线冰堵的探讨

在北方冬季输送成品油时,由于多种原因存在于油中的水会在管内壁结冰,严重时会形成冰堵而影响输送。本文通过实验结果和理论分析,揭示了成品油管内壁结冰的机理。并提出了预防冰堵发生的措施。