焦炉端部火道揭顶翻修技术应用

介绍了2座6 m焦炉的工程概况,分析了焦炉端部火道炉墙损坏的主要外因及采用熔融硅砖对端部火道进行揭顶翻修的优点。通过揭顶翻修解决了端部火道炉墙破损、变形及炉头冒烟着火问题,且较使用普通硅砖总工期缩短约110天,可减少焦炭损失约23 210 t,2座焦炉的焦炭产量较维修前提升了50%以上。

Quench sensitivity and microstructure character of high strength AA7050

The effect of quenching rate on the electrical conductivity and microstructure of thick plates of incumbent AA7050 was investigated by employing Jominy end quench test. The electrical conductivity measurement and microstructural observation were conducted at different distances from the quenched end. The results indicate that the average cooling rates decrease with increasing the distance from the quenched end of the bar in the quench sensitive temperature range. However, the electrical conductivity increases with the increase of distance from the quenched end. The surface parts of the plate were fully recrystallized, while partial recrystallization took place at the quarter and center parts of the plate. The quench induced grain boundary precipitates became remarkably coarser and discontinuously distributed with increasing distance from the quenched end of the bar. Plenty of heterogeneous precipitates were observed to nucleate on A13Zr dispersoids when the distance from the quenched end was greater than 38mm.

Effect of homogenization time on quench sensitivity of 7085 aluminum alloy

The effect of homogenization time on quench sensitivity of a cast 7085 aluminum alloy was investigated by means of end-quenching test, optical microscope （OM）, scanning electron microscope （SEM） and transmission electron microscope （TEM）. The results show that with the increase of homogenization time from 48 h to 384 h, quench sensitivity increased slightly as the largest difference in the hardness was increased from 5.2% to 6.9% in the end-quenched and aged specimens. Prolonging homogenization had little effect on the grain structure, but improved the dissolution of soluble T phase and resulted in larger Al3Zr dispersoids with a low number density. Some small quench-induced η phase particles on Al3Zr dispersoids were observed inside grains during slow quenching, which decreased hardness after subsequent aging. The change in the character of Al3Zr dispersoids exerted slight influence on quench sensitivity.

巧改热水器

夏天使用燃气热水器时,出水较烫,若将火焰调小,又会造成燃烧不完全,导致燃气浪费,还污染居室空间。为此,可将热水器罩除下,从远离常明火端开始。

Finite element simulation and microstructure of two-pass inner spinning process of curved-generatrix cone cylindrical parts with annealing/quenching

A two-pass annealing/quenching internal spinning process with small-end rotations is proposed to form a curved generatrix conical thin-walled shell.That is,annealing at 360°C for 2 h followed by the 1st pass spinning,and finally quenching in ice water after holding for 1 h at 498°C followed by the 2nd pass spinning.ABAQUS finite element software is used to simulate the internal spinning process of the products formed under different forming parameters.The distribution laws of spinning force,the stress and strain under different forming processes were compared and analyzed.The mechanical properties and microstructure of the products are subsequently analyzed.The results show that the strain and the residual stress in the skin area of the formed products under two-pass spinning process more uniform,and the hardness and the mechanical performance are improved.The microstructure of the products formed with the 0.15 mm thickness reduction at the 2nd pass is excellent.And the second phase grain size distributed uniformly in the range of 36μm.Whereas,the second phase particles are broken seriously and the size distribution inhomogeneity is increased when the thickness reduction in the skin area is greater than 0.20 mm at the 2nd pass spinning process.

基站新型多系统协同供备电设计分析及应用

移动通信基站从2G/3G/4G演进到了5G时代,网络带宽大幅度增加,基站密度与数量也随之大幅度增多,导致了网络设备对基站机房/机柜及电源数量、输出容量等需求成倍增大(供电损耗也随之成倍增大),基站机房/机柜及电源建设与节能降耗难度也随之增加,在国家碳达峰与碳中和(即“双碳”)目标需求驱动下,须采取积极的措施来不断提升基站机房/机柜及电源的创新能力、供应能力、利用效率、能效比等。提出市电输入近端搭火、井盖供备电(包括地埋机房/机柜、雨水井、检查井等)、塔上风光互补供备电/补电等基站新型供备电设计,并分析提出将市电输入近端搭火后的市电输送入基站传统供备电系统、井盖供备电与塔上风光互补供备电/补电系统进行控制与管理,多个供备电系统合路后按一定比例输出,协同给基站设备供备电,解决市电引入距离过长不满足供电需求、市电无法到达或容量不足、市政容貌要求不能建机房或立柜、小型基站/微基站等站点的供备电无计可施的难题,为基站设备提供灵活配置、高效节能、稳定可靠、绿色智能的电能,构建绿色低碳通信网络。

A New Indicator Cell Line Established to Monitor Bovine Foamy Virus Infection

In order to improve the accuracy for quantitating the bovine foamy virus (BFV) in vitro,we developed a baby hamster kidney cell (BHK)-21-derived indicator cell line containing a plasmid that encodes the firefly luciferase driven by the BFV long terminal repeat promoter (LTR,from-7 to 1012).The BFV titer could be determined by detecting the luciferase expression since the viral trans-activator BTas protein activates the promoter activity of the LTR.One clone,designated BFVL,was selected from ten neomycin-resistant clones.BFVL showed a specific and inducible dose-and time-dependent luciferase activity in response to BFV infection.Although the changes in luciferase activity of BFVL peaked at 84 h post infection,it was possible to differentiate infected and uninfected cells at 48 h post infection.A linear relationship was established between the multiplicity of infection (MOI) of BFV and the activated ratio of luciferase expression in BFVL.Moreover,the sensitivity of the BFVL-based assay for detecting infectious BFV was 10,000 times higher than the conventional CPE-based assay at 48 h post infection.These findings suggest that the BFVL-based assay is rapid,easy,sensitive,quantitative and specific for detection of BFV infection.

计算机病毒——暗藏的幽灵

1989年10月13日,星期五,荷兰全国10万台计算机突然失灵,同一天,欧洲、亚洲数以百万计的计算机也同时瘫痪,造成数以十亿美元计的经济损失,这是一种名为“黑色星期五”的计算机病毒作怪的结果,这种病毒因为是13号同时又是星期五这一天而得名。 计算机病毒已有较长历史,早在本世纪40年代,计算机之父冯·诺依曼就提出本世纪机械的自动复制理论,后来,美国著名的贝尔实验室开发了一种游戏程序“CORE WAR”(核心战争),该程序可以控制并攻击其他程序。