Effect of thermomechanical treatment on mechanical properties and electrical conductivity of a CuCrZr alloy

The CuCrZr alloy undergoes processes of precipitation during ageing. Besides precipitation hardening the strength is affected by cold deformation which is performed before and after ageing. The cold deformation (D ₁) before ageing accelerates the process of strength hardening, since it induces higher rate of precipitation from the saturated a-sold solution. Cold deformation (D ₂) after ageing primarily affects the alloy strength. In this paper the results of the effect of thermomechanical treatment on mechanical properties and electrical conductivity of a CuCrZr alloy are presented. The aim of the paper was to evaluate the most suitable combination of thermomechanical treatment and alloy properties.     

Ti-23Al-14Nb-3V合金氩弧焊接头的显微组织及其力学性能

研究了预热对Ｔｉ－２３Ａｌ－１４Ｎｂ－３Ｖ合金焊接性，特别是对消除氩弧焊冷裂纹的作用以及对接头显微组织和力学性能的影响。结果表明，焊前预热可有效降低该合金的冷裂倾向。经预热处理后，焊缝区的结晶层状线消失，热影响区的硬度峰得到缓和，整个焊缝的显微硬度分布趋于均匀，但焊缝区的枝晶发生粗化，热影响区有所扩大。焊件接头的拉伸试验表明，预热可使焊缝区的接头强度系数增加，但无论预热与否，接头强度均低于母材强度，且不显示宏观塑性。     

广州地铁集中冷站的自动控制

本文介绍广州地铁二号线集中冷站的空调制冷自动控制系统的设计，对其控制原理与节能优化进行分析。     

四种国民常用饮水中非挥发性有机物及其致突变活性的比较研究

比较我国居民常用饮水种类自来水、净化水(自来水经净水器过滤)、凉开水(自来水经煮沸后冷却)、纯净水(自来水经以反渗透为主的多重工艺处理)的非挥发性有机物(NOP)污染状况及其致突变活性。结果表明,四种水中检测到的NOP种类分别为自来水39种,净化水40种,凉开水20种,纯净水8种;毛细色谱显示的NOP总丰面积值依次为5.62×109,5.57×109,2.65×109,1.87×109。四种水的移码型及碱基置换型致突变活性依次为:自来水>净化水>凉开水>纯净水,其中自来水在相当1L、2L、4L水量的剂量均为阳性致突变活性,而纯净水在同样的剂量均为阴性。     

用脉冲全息法分析冲床的动态特性

介绍了双脉冲激光全息照相对机床结构动态特性的现场测量技术,并应用它成功地分析研究了冲床整机的动刚度和振型。     

WXJB—E型多点温度监测报警仪的研制

本文介绍了 WXJB—E 型多点温度监测报警仪的设计思想、基本原理、技术关键、技术指标及其功能。     

Mannitol and oligosaccharides as new criteria for determining cold tolerance in sugarcane varieties

Sugarcane can be very susceptible to damage by freezes. Freeze-deteriorated cane can cause problems in processing and sometimes leads to a factory shut-down. This study was undertaken during the 2000/2001 harvest season to assess the cold tolerance performance of six commercial sugarcane varieties and to establish new and more sensitive criteria to measure cold tolerance. Two varieties CP 70-321 and CP 79-318, with known cold tolerance, were planted in the study as controls. The other varieties included LHo 83-153, LCP 85-384, HoCP 85-845 and HoCP 91-555. Freezing temperatures occurred on 20 December 2000 when the min. field temperature was −4.4 °C, and again on 21 December, 30 December through 5 January 2001, 9–10 January and 20–21 January. The lowest field temperature recorded was −5.6 °C on 4 January. Freezing conditions prevailed for 8–15 h during each freeze incident. Stalks of all varieties were frozen to the ground following the initial freeze, with freeze cracks evident only after the 4 January freeze. For this study, samples were taken on the date of the first freeze, 20 December, and subsequently again at 7, 14, 22 and 30 days after the first freeze. Criteria used to measure overall stalk cold-tolerance included changes in pH, Brix, dextran (ASI-II method), sucrose, glucose, and fructose concentrations. Mannitol, ethanol and the oligosaccharides, palatinose, leucrose, iso-maltotriose and 1-kestose, were simultaneuously measured using IC-IPAD. Marked differences were observed in most criteria for all varieties, particularly 22 and 30 days after the first freeze. Mannitol was strongly correlated (r²=0.84) with dextran, confirming its use as an indicator for cane dextran deterioration. In comparison, ethanol was only weakly correlated (r²=0.55) with dextran and did not always predict cane dextran deterioration. Iso maltotriose was the most sensitive oligosaccharide indicator of freeze deterioration, although both leucrose and palatinose could be used to confirm whether severe dextran formation (>1500 ppm/Brix) has occurred in cane. Isomaltotriose was strongly correlated (r²=0.89) with dextran and pH (r²=−0.83); pH was also a strong indicator of both dextran (r²=−0.85) and mannitol (r²=−0.92) formation. Four of the varieties, CP 79-318, LCP 85-384, HoCP 85-845 and HoCP 91-555, were shown to be susceptible to other sources of microbial and enzymic deterioration as well as dextran deterioration from Leuconostoc bacteria, especially 30 days after the first freeze. This was indicated by increased glucose/fructose ratios, ethanol formation, changes in 1-kestose concentration, and further sucrose losses.     

水泥厂低投入高回报的技改途径

俄罗斯的一些水泥厂以最少的投入进行技改,旨在提高其生产效率。借助现代选粉技术改造水泥粉 磨系统,并给现有的篦式冷却机装备静止的入口段,可以低的投资,快速获取投资回报。     

Q195冷轧板材轧制困难原因分析

针对部分Q195冷轧板材存在轧制困难的现象，进行了现场检验与分析。带状组织、混晶现象严重导致变形强化系数偏高是造成轧制困难的主要原因。     

双隔膜压滤机在高炉煤气洗涤污泥脱水中的应用

针对南钢历年来在高炉煤气洗涤水污泥脱水处理中遇到的压滤机的问题，指出了单隔膜压滤机的缺陷，并在充分词研和实际应用的基础上改用厢式双隔膜高效板框压滤机，取得了较好的效果。