在多室环流反应器中用FCC干气制备乙醛

在多室环流反应器(MALR)中用模拟和真实的催化裂化干气制备了乙醛，考察了反应温度、反应压力、原料气中乙烯浓度和催化剂溶液中钯离子(Pb^2 )浓度对乙烯的单程转化率和乙醛选择性的影响。结果表明，在多室环流反应器中用FCC干气制备乙醛的适宜条件为：反应温度100～120℃，反应压力0．5～0．6MPa，催化剂溶液中Pb^2 质量浓度为0．6～0．9g／l。     

浅谈数值修约的一般方法

文章介绍了数值修约规则的新旧标准差异,结合金属材料拉伸试验实例,阐述数值修约的一般方法。     

压榨螺旋维修的技术探讨

压榨螺旋广泛地用于制浆段浆料的脱水浓缩,为后续工序如热分散系统提供25%～30%浓度的浆料。压榨螺旋的脱水作用非常重要,同样磨损也是异常厉害,磨损后其脱水浓缩作用会明显下降,甚至造成浆料的堵塞。本文重点介绍维修的相关技术和经验。     

氟化铝母液脱硅方法的实验研究

介绍了氟化铝母液脱硅方法的原理、实验设备以及工艺流程，深入系统的研究了氯化钠投加量与脱硅后母液氟硅酸钠残量的关系，脱硅过程中总氮、总铝的损耗与母液总酸的关系，固形物产率分析等。     

60CrMnMo锻造轧辊脱肩原因分析

通过对60CrMnMo锻造轧辊脱肩样品的一系列分析,明确了其开裂原因。轧辊在生产过程中吊空冷时间长、晶界析出脆性碳化物、冷却速度快、体积变化大、淬火应力大,形成淬火裂纹并造成锻件开裂。     

Controllable resistive type fault current limiter (CR-FCL) with frequency and pulse duty-cycle

In this paper a controllable resistive type fault current limiter (CR-FCL) is introduced. The CR-FCL inserts a pre-specified value of resistance based on a pre-defined function, by using a simple switching method, in series with the fault current path. When a fault occurs, a self turn off switch starts switching with a pre-specified frequency and duty cycle. By this switching pattern, the controlled value of resistance enters to the fault current path. So, the CR-FCL limits the fault current to the desired values. In addition, from transient stability point of view, by inserting the optimal resistance value, the CR-FCL is capable to enhance power system transient stability in a good manner. In fact, generation of the controllable resistance that depends on the duty cycle of the self turn off switch is the main idea of the CR-FCL. The variable duty cycle results the variable resistance and the fixed duty cycle results the fixed resistance. Analytical analyses of the proposed FCL are presented in details. Simulation results by power system computer-aided design/electromagnetic transients, including dc (PSCAD/EMTDC) software and corresponding experimental results are studied to validate the effectiveness of the CR-FCL. Considering error analyses, there is the good agreement between the simulation results and the experimental results.     

输水管道工程试验段施工分析

DN1800球墨铸铁管K型机械式接口管道试验段施工，以每一施工工序为分段，在施工排水、管沟开挖、基础处理、管节起吊、管道安装、水压试验、管沟回填等方面依次进行。其中，施工排水是管沟开挖成形的前提条件，经过井点降水后，管沟边坡稳固；在施工时采用不同方式调整管节之间的对口间隙和环形间隙，保证管道安装的轴向位置和高程；单口水压试验是对管道接口安装进行的一次专项检查，整体水压试验是对管道进行的一次综合性检验，根据规范要求，试验段管道安装水压试验必须合格；在施工中严格控制回填土每层的虚铺厚度、含水率和每层压实遍数，保证回填土的压实度满足设计要求。     

钢筋网焊机下料机械手设计

钢筋网焊接过程中下料大多采取人工码垛,耗费工时、工人劳动强度大、码垛时整齐度不够,并且在码垛过程中容易对钢筋网搭接焊点造成一定的损害。针对钢筋网的下料和码垛,设计了一套机械手,可以实现焊接钢筋网的自动抓取下料,并且能够按照生产要求实现多位置码垛。     

Effect of atmosphere composition on the quality of ready‐to‐use broccoli raab (Brassica rapa L.)

BACKGROUND: Many leafy brassicas are widely used for ready‐to‐use salads. Broccoli raab (Brassica rapa L.), also called turnip top, or rapini, is extensively cultivated in southern Italy. The edible portion is made up of the green, immature inflorescences and the stem with its most tender leaves. Recently, interest in this crop has increased among European consumers; moreover, a substantial increase in consumption could come from the ready‐to‐use product. RESULTS: The effects of four different atmosphere compositions (air, 3% O₂ in nitrogen, 3% O₂ + 10% CO₂ in air, and 10% CO₂ in air) on quality attributes of ready‐to‐use broccoli raab were studied. Controlled atmosphere affected appearance, composition, respiration rate, weight loss, and presence of off‐odours. Storage of broccoli raab florets under low oxygen conditions delayed post‐cutting deterioration during storage at 5 °C and preserved appearance and typical odour, up to 17 days. Moreover, respiration rate as well as loss of green colour, chlorophyll and vitamin C were also slowed down in this condition. Finally, in this study no effect of controlled atmosphere storage was found on total phenols content and antioxidant activity. CONCLUSION: Results showed that cold storage in 3% O₂ can be beneficial in order to maintain quality of ready‐to‐use, broccoli raab for up to 17 days. Copyright © 2010 Society of Chemical Industry     

槽钢冲缺口模设计

分析了槽钢零件的结构特点及原生产工艺存在的缺点与不足，介绍了在槽钢上冲缺口的工艺、模具结构及冲模工作过程,使用该冲缺口模具提高了生产效率，满足了产品的质量要求，维修方便，降低了成本，提高了经济效益。