带镍基隔离层耐热钢与不锈钢焊接工艺研究

针对带镍基隔离层耐热钢与不锈钢焊接,从材料焊接性、焊接方法、焊材选用、焊接工艺设计、焊接试验等方面进行研究.根据焊后弯曲试验的结果,增加焊前预热和焊后热处理,调整对接焊的焊接形式,获得满足现场施焊要求的焊接工艺.     

换热器管子-管板焊接现状和改进方法

概述了国内换热器管子管板焊接的一般现状,由于其焊接的局限性和特殊性,焊接质量参差不齐.从前期坡口设计到焊接和检验过程提出了改进方法,主要是要选用易于焊透的坡口型式和尺寸,焊前进行模拟工艺试验及焊工考核.采用高性能设备的自动焊对焊接工艺进行升级,重视焊前及焊接过程的细节控制,加强焊缝的检验等,共同保证管子管板焊接工艺条件...     

CFB锅炉炉管改造焊接质量控制

通过分析热电厂CFB锅炉改造中影响炉管焊接质量的重要因素,从焊接工艺评定与焊接工艺、焊接材料、焊工培训、施焊过程、焊后检验和焊缝返修等六个方面进行了论述,提出了保证焊接质量应采取的工艺措施,对提高炉管焊接质量具有指导作用.     

415mm特厚锻件工作缸的焊接制造

本文介绍了窄间隙埋弧焊在415mm特厚锻件焊接中的应用,通过工艺试验及工艺评定确定了焊接坡口,并提出了手工焊封底后在不清根的情况下直接采用埋弧自动焊进行焊接的方法,取得良好效果.     

大型储罐自动焊工艺

文章结合大型储罐焊接工程自动焊的成功应用实例,对大型储罐气电立焊和埋弧横焊相结合的自动焊组合工艺,从焊接设备构成、焊接工艺原理、焊接工艺流程、焊接材料选择、焊接工艺参数、焊接操作要领、焊缝缺陷产生原因及防治等方面进行了较详细的论述和探讨,以期提高大型储罐自动焊的外观成型和焊接内在质量,提高焊接施工效率和经济效益。     

珠光体耐热钢的焊接

主要介绍了珠光体耐热钢的焊接方法、焊接材料的选择、焊前预热温度、焊后热处理及其焊接性能等方面的内容,并针对本厂的生产结构制订12Cr1MoV材料的工艺评定、焊接工艺参数以及焊后热处理工艺等。     

空分装置铝镁合金塔设备的现场组对焊接

通过对空分装置铝镁合金塔设备现场横焊环缝焊接性进行分析,制定了相应焊接工艺,提出了针对性焊工考试要求,在工程中成功进行了应用.采用手工交流TIG、双人双面同步焊焊接方法,采取严格的焊前清理去除水分,氧化膜措施,焊前和焊接过程中进行预热,是保证厚壁铝镁合金塔设备现场焊接质量的关键.     

石化装置用工业纯钛电子束焊接头组织及力学性能

采用电子束焊,对工业纯钛TA2进行了焊接试验,获得了最佳焊接工艺参数;通过电子束焊工艺评定试验,表明采用电子束焊焊接镍基高温合金可以得到良好的焊接接头,各项性能均满足要求;实践证明,电子束焊焊接工艺具有变形量小、无损检测合格率高等优点,能够保证产品焊接质量,真空电子束焊接技术可应用于石化装置用工业纯钛产品的制造。     

管子-管板内孔自动焊的焊接

本文分析了管子-管板内孔自动焊的管板管孔加工、焊接工艺试验、焊接工艺评定、以及焊接过程中的技术要求。通过前期的技术准备,如:焊接工艺试验、焊工培训、焊接工艺评定、背气保护工装的制作等;制定了管子-管板内孔自动焊的施工方案。低压反应水冷凝器的成功制作,拓展了本公司在管子-管板自动焊的焊接领域。     

水力除焦钻杆P110的焊接技术

对P110材质焊接性进行分析,确定了焊接方法,确定了焊接工艺参数及焊后热处理工艺。指出现场焊接时控制热输出及焊后热处理是焊接工艺的关键。     

佛山市顺德新城区降水中污染物的监测和分析

为掌握佛山市顺德新城区降水中污染物的情况,2015年7月至8月,文章作者分别在雨天进行了降水取样,对降水中的pH、电导率、常见阴离子(F-、Cl~-、NO_3~(2-)、SO_4~(2-))及部分重金属(铅和镉)进行监测分析。选择有相关数据的珠江三角洲和石家庄、厦门等地的降水中污染物的情况进行对比。结果表明,顺德新城区降水中的p H和部分阴离子浓度优于珠江三角洲平均值,酸雨类型属于硫酸和硝酸混合型;其水体洁净程度略差于石家庄;铅和镉的浓度也高于厦门,甚至部分超出了人体能直接接触的安全范围。     

Metabolism of trideuterated iso-lignoceric acid in rats in Vivo and in human fibroblasts in culture

Saturated very long chain fatty acids (fatty acids with greater than 22 carbon atoms; VLCFA) accumulate in peroxisomal disorders, but there is little information on their turnover in patients. To determine the suitability of using stable isotope-labeled VLCFA in patients with these disorders, the metabolism of 22-methyl[23,23,23-²H₃]tricosanoic (iso-lignoceric) acid was studied in rats in vivo and in human skin fibroblasts in culture. The deuterated iso-VLCFA was degraded to the corresponding 16- and 18-carbon iso-fatty acids by rats in vivo and by normal human skin fibroblasts in culture, but there was little or no degradation in peroxisome-deficient (Zellweger’s syndrome) fibroblasts, indicating that its oxidation was peroxisomal. Neither the 14-, 20-, and 22-carbon iso-fatty acids nor the corresponding odd-chain metabolites could be detected. In the rat, the organ containing most of the iso-lignoceric acid, and its breakdown products, was the liver, whereas negligible amounts were detected in the brain, suggesting that little of the fatty acid crossed the blood-brain barrier. Our data indicate that VLCFA labeled with deuterium at the ω-position of the carbon chain are suitable derivatives for the in vivo investigation of patients with defects in peroxisomal β-oxidation because they are metabolized by the same pathways as the corresponding n-VLCFA. Moreover, as iso-VLCFA and their β-oxidation products are readily separated from the corresponding n-fatty acids by normal chromatographic procedures, the turnover of VLCFA can be more precisely measured. A preliminary report of part of this work (Reference 18) was presented at the 5th International Symposium on the Synthesis and Applications of Isotopes and Isotopically Labelled Compounds, Strasbourg, France, June 20–24, 1994.     

高效液相色谱法分析化妆品中微量成分的研究进展

综述了高效液相色谱法在化妆品中防腐剂、防晒剂中紫外线吸收剂以及性激素的检测等几个方面的应用;同时,介绍了分析所用的色谱柱、流动相、使用的检测手段以及样品的提取方法;最后针对目前存在的问题,提出了高效液相色谱用于化妆品中微量成分分析的研究方向和发展前景。     

Denitrification in shallow groundwater in a coastal agricultural area in Japan

In a coastal agricultural area in the central part of Japan (Shizuoka), we found decreasing nitrate concentration with depth in a shallow groundwater, where the depth to water table varied between 0.6 and 1.2 m below ground surface. High nitrate concentrations (5–29 mg N L^–1) were often observed in the upper layer (0–2 m) of the groundwater, but the concentration decreased to less than 1 mg N L^–1 in the deeper layer. Ammonium was scarcely detected, and the concentration of dissolved oxygen was usually low (< 1 mgO₂ L^–1) in the groundwater. Nitrate in the groundwater often had very heavy nitrogen stable isotope ratios (>20{}). There was a negative relationship between nitrogen stable isotope ratio of nitrate and its concentration. When nitrate was injected into the groundwater with acetylene and bromide (a conservative tracer), nitrate concentration decreased to 20% of the initial level within 5 days, accompanied by the increase in nitrite and nitrous oxide concentration and a little change in bromide concentration. These results indicate that microbial denitrification plays a potential role in the decrease of nitrate in shallow groundwater at the study site.     

我国硝酸工业生产技术新进展

系统叙述了我国硝酸工业2000-2007年生产现状及主要技术成果,尤其指出了国产"四合一"机组的成功投运,使我国硝酸国产化装置取得较大的进步,表现在吨酸的铂耗、氨耗和能耗等方面接近国外引进装置水平,同时介绍了国外双加压法硝酸生产技术的进展.我国已成为硝酸生产大国,仍需以先进的技术改造和发展我国硝酸工业,确保我国硝酸工业健康有序地发展,加快从硝酸生产大国向强国迈进的步伐.