The Invalidation Analysis of a Working 5 CrMnMo Forging Die and Ways of Precaution

The paper introduced the 5 CrMnMo steel, including the chemical composition, the heat treatment technology, the forging die working condition, and the invalidation form （such as the cavity arris wear, the cavity subsidence, the cold and the heat fatigue crackle）. Then gave some precautions for prolonging the mould life by improving the heat treatment technology.     

乙酰柠檬酸三丁酯的催化合成

目前常用的邻苯二甲酸酯类增塑剂可能诱发致癌,国内外都在寻找能够替代的无毒增塑剂,柠檬酸酯类增塑剂是安全的替代增塑剂之一.今以柠檬酸三丁酯和乙酸酐为原料,研究了硫酸氢钠、大孔强酸性阳离子交换树脂催化合成乙酰柠檬酸三丁酯的过程,考察了原料摩尔配比、催化剂用量、反应时间、反应温度对乙酰柠檬酸三丁酯收率的影响.在适宜条件下,两种催化剂催化合成乙酰柠檬酸三丁酯的收率可分别达到99.5%和99.8%.精制后,乙酰柠檬酸三丁酯的含量经气相色谱分析大于99%.催化剂重复使用情况的考察表明:硫酸氢钠有较好的重复使用性;使用后经无水乙醇洗涤并干燥过的大孔强酸性阳离子交换树脂也具有很好的重复使用性.     

Native Liquid Chromatography and Mass Spectrometry to Structurally and Functionally Characterize Endo-Xylanase Proteoforms

Xylanases are of great value in various industries, including paper, food, and biorefinery. Due to their biotechnological production, these enzymes can contain a variety of post-translational modifications, which may have a profound effect on protein function. Understanding the structure–function relationship can guide the development of products with optimal performance. We have developed a workflow for the structural and functional characterization of an endo-1,4-β-xylanase (ENDO-I) produced by Aspergillus niger with and without applying thermal stress. This workflow relies on orthogonal native separation techniques to resolve proteoforms. Mass spectrometry and activity assays of separated proteoforms permitted the establishment of structure–function relationships. The separation conditions were focus on balancing efficient separation and protein functionality. We employed size exclusion chromatography (SEC) to separate ENDO-I from other co-expressed proteins. Charge variants were investigated with ion exchange chromatography (IEX) and revealed the presence of low abundant glycated variants in the temperature-stressed material. To obtain better insights into the effect on glycation on function, we enriched for these species using boronate affinity chromatography (BAC). The activity measurements showed lower activity of glycated species compared to the non-modified enzyme. Altogether, this workflow allowed in-depth structural and functional characterization of ENDO-I proteoforms.     

汽轮机低真空运行循环水供热技术应用

本文介绍了汽轮机低真空运行循环水供热技术在C12-35/10机组上的应用,并结合工程实例,对低真空运行循环水供热的经济性和安全性进行了分析、探讨。     

Measurement of heat transfer coefficients for steam condensation on a vertical 21.5-mm-O.D. tube in the presence of air

ABSTRACT

Governing the rate of heat transport by condenser tubes in the passive containment cooling system (PCCS), the steam condensation over a vertical cylinder in the presence of air was investigated experimentally. The main objective of this study was to explore if the condensation heat transfer coefficient relies on the tube dimension, which has been a variable missed in most condensation models or has been embraced without experimental demonstration under phase change environments. The mean heat transfer coefficient was measured in the condensation test facility named JERICHO (JNU Experimental Rig for Investigation of Condensation Heat transfer On tube). The outer diameter of the condenser tube used in this study was set to 21.5 mm. The measured heat transfer coefficients were compared to those obtained from the 40-mm-O.D. tube, and a multiplier to correct the variation of the heat transfer coefficient with the tube diameter was proposed for its application to Lee correlation. The proposed correlation was further validated against another set of experimental data obtained from a separate test facility housing the 31.8-mm-O.D. tube.     

ACME台架蒸汽发生器传热特性数值模拟

以ACME台架的蒸汽发生器（SG）为研究对象,SG二次侧选用两流体模型,采用计算流体力学软件CFX对ACME台架的SG进行了整体直接模拟。针对稳定试验工况进行了计算,得到了SG一、二次侧的温度分布,二次侧空泡份额分布及传热管的壁温等参数沿U型管高度方向的变化,获得了二次侧较详细的流动和传热特性。计算结果表明,从第2道折流板开始,折流板底部已积聚了部分气泡,随高度的增加,折流板底部积聚的气泡越多,在弯管区附近及以上区域,已全部变为蒸汽。本文计算结果与试验结果符合较好。     

不同网格中导热方程的精确解和数值解

用基元有限容积方法求解热传导问题,结构化网格和非结构化网格同时采用,并和精确解相比较.虽然从两种网格形式,都能得到满意的结果,但结构化网格在规则区域更精确一些.对于非结构化网格,二次扩散项对提高精度是十分重要的.     

Distortions and tensile properties of 15-5PH steel cylinders with EBW and heat treatment

15-5PH steel is one of the martensitic precipitation-hardened stainless steels, which is extensively applied in the aero shafts, and electron beam welding is a significant procedure to manufacture the parts. To verify the dimension accuracies and properties, EBW with oscillation was employed on the cylinders of 15-5PH steel. The welding distortions were measured, and the microstructures and tensile properties of the joints were investigated. The weld appearances of the cylinders were smooth, and the morphology was parallel. After EBW, the shrinkages of the cylinders were above ?0.22?mm, and the welding distortions were ?0.66 to ?1.1‰, and the straightnesses were less than 1‰ due to the distortions. The martensites and a few austenites were in the welds of the cylinders after heat treatment, and the microhardnesses in the welds were 445 HV0.2, which were bigger and more homogeneous than those of the as-welded. The tensile strength and yield strength of the joints were respectively 1300 and 1150?MPa, which were higher than those of the as-welded joints, and the elongation rate of the joints was 10%. The microstructures and properties of the cylinders conformed to the aero shafts, which was attributed to the microstructure transformation with oscillation EBW and heat treatment.     

离子交换法从硫酸亚铁溶液中分离镍实验研究

本文针对高铁低镍硫酸亚铁溶液中镍铁分离困难的生产实际,采用离子交换技术对硫酸亚铁溶液中的镍铁分离进行了研究。通过条件实验考察了树脂装填量、吸附前液pH值、吸附时间、镍离子浓度等对镍铁分离效果的影响。结果表明,CH-90树脂对含镍硫酸亚铁溶液中镍有明显的优先选择性,树脂对镍的工作交换容量为15 mg/g。经过离子交换树脂处理,溶液中的铁镍摩尔比由处理前的17:1最高可以提高到93:1,镍去除率达到87%,处理后溶液含镍小于0.3 g/L,具有良好的分离效果。改变初始浓度和吸附反应时间,探究了树脂的吸附等温线和吸附动力学过程,发现树脂符合Langmuir吸附和准二级动力学方程,说明吸附属于单分子层吸附和定点吸附,吸附过程主要是离子交换控制的。