大型循环水泵出口管道膨胀节使用与支架设计

循环水站中大型循环水泵进出口管道由于膨胀节的选用不当和安装偏差,以及管道支架设置不合理,往往会导致启泵失败,甚至对泵造成损坏.通过对两个工程实例进行分析研究和应力分析模拟计算,给出膨胀节和管道支架整改方案,改进后循环水泵启停正常、运行平稳.最后对该类管道上膨胀节的选用与安装,支架设计提出建议.     

三旋烟道膨胀节取消蒸汽保护的可行性

１前言我厂催化裂化装置三旋烟道的介质温度高达650～700℃，过去，烟道的热补偿采用U形波纹管膨胀节，为了降低膨胀节的设计及操作温度，通常采取蒸汽保护措施，但会加快膨胀节的腐蚀，这主要是由于水蒸汽凝结、沉积、烟气冷却引起波纹管的点蚀和应力腐蚀。我厂三旋烟道系统共有21个膨胀节，近几年来，先后有8个膨胀节发生腐蚀、泄漏问题，严重影响了安稳长运行。为此，于1992年4月取消了三旋烟道系统所有膨胀节的冷却保护蒸汽，经过两年多的运行，至今未出现腐蚀泄漏问题，不仅延长了膨胀节的使用寿命，保证了装置的安稳长运行，而且降低…     

化工生产中换热器膨胀节弯曲半径的确定

用一具体实例分析了化工生产中膨胀节爆裂的原因，说明设计非标膨胀节时，怎样确定弯曲半径．以提高膨胀节的寿命。     

EA—1013／1063换热器膨胀节的改进设计

对进口换热器膨胀节与国产化后的换热器膨胀节以及改进设计后的三种不同结构的换热器膨胀节进行受载分析及校核，膨胀节改进设计后取得了较好的经济效益。     

EA－1013／1063换热器膨胀节的改进设计

对进口换热器膨胀节与国产化后的换热器膨胀节以及改进设计后的三种不同结构的换热器膨胀节进行受载分析及校核，膨胀节改进设计后取得了较好的经济效益。     

常压炉烟道膨胀节的腐蚀与防护

简要介绍了常压炉烟道膨胀节的使用及腐蚀状况，并初步分析了产生腐蚀的原因。针对这种情况，采取了提高膨胀节的使用温度及改善燃料结构等措施，有效地延长了膨胀节的使用寿命。     

延长窑尾烟室膨胀节使用寿命的措施

梅州市塔牌集团蕉岭鑫达旋窑水泥有限公司（以下称我公司）是广东塔牌集团股份有限公司下属企业，有一条5　000t/d由天津水泥工业设计研究院设计的100%燃烧无烟煤的熟料生产线。该线于2003年6月建成投产，窑尾烟室膨胀节以前均为外购的波纹管补偿器，上、下两端的法兰分别和分解炉以及烟室焊接连接,呈密封状态,以减少系统的外漏风。但在生产过程中,当原、燃材料中的有害成分(K2O、Na2O、SO3、MgO)含量较高时，烟室及附近膨胀节内壁易结皮，必须及时清理，否则就会影响系统的正常通风，而高频率清理结皮，易造成膨胀节内部耐火材料损坏，最终造成膨胀节的损坏，导致此处漏风。为解决上述问题，我公司对此处的膨胀节进行了简单的移位改造，达到了延长膨胀节使用寿命的目的。     

姜堰市扬子江管道设备有限公司企业简介

姜堰市扬子江管道设备有限公司是专业生产各种不锈钢金属软管。波纹膨胀节，非金属膨胀节，软连接的企业，产品严格采用美国膨胀节制造商协会（EJMA）和国标GB／T12777-1999．GB／T14525-1993标准。以综合性能为目标。进行计算机优化设计，使产品质量优良，品种繁多，规格齐全，质量可靠，产品已通过ISO9001：2000认证。     

1Cr18Ni9Ti波纹管膨胀节失效分析及改进

本文主要根据１Ｃｒ１８Ｎｉ９Ｔｉ波纹管膨胀节在催化车间烟道上的使用情况，分析其失效的机理，并改用Ｂ－３１５钢波纹管膨胀节代替的使用情况及其经济效益。     

平面铰链型膨胀节的极限设计法

以DN2 200mm平面铰链型膨胀节为例,借助有限元软件,将压力容器的极限载荷分析法应用于膨胀节的设计,结果发现:应用极限载荷分析法设计膨胀节,除了能进行强度评判外,也能计算出膨胀节各方向的位移和膨胀节的许用载荷,并可以较容易的对膨胀节进行轻量化设计。     

纽结理论与三叶结分子合成研究进展

拓扑学中的纽结理论在化学和生物学中有非常重要的应用,首先介绍了纽结理论在化学中的应用发展,然后对三叶结分子合成方法的发展及其可能的反应机理进行了阐述。     

大碹密封料选择错误引起的玻璃缺陷

利用光学显微镜和扫描电镜-能谱仪,对浮法玻璃生产线产生的玻璃缺陷-疖瘤进行检测,结合玻璃熔窑结构及所用耐火材料进行排查,根据疖瘤的成分找出了疖瘤的产生原因为使用了不恰当的密封泥料造成。利用高温内窥镜对熔窑大碹进行了探测,并给出了解决措施。     

A Cactus‐Derived Toxin‐Like Cystine Knot Peptide with Selective Antimicrobial Activity

Naturally occurring cystine knot peptides show a wide range of biological activity, and as they have inherent stability they represent potential scaffolds for peptide‐based drug design and biomolecular engineering. Here we report the discovery, sequencing, chemical synthesis, three‐dimensional solution structure determination and bioactivity of the first cystine knot peptide from Cactaceae (cactus) family: Ep‐AMP1 from Echinopsis pachanoi. The structure of Ep‐AMP1 (35 amino acids) conforms to that of the inhibitor cystine knot (or knottin) family but represents a novel diverse sequence; its activity was more than 500 times higher against bacterial than against eukaryotic cells. Rapid bactericidal action and liposome leakage implicate membrane permeabilisation as the mechanism of action. Sequence homology places Ec‐AMP1 in the plant C6‐type of antimicrobial peptides, but the three dimensional structure is highly similar to that of a spider neurotoxin.     

玻璃器皿口部积瘤的研究

玻璃器皿口部积瘤的研究曾孝宇，张建国，徐洪福（天津轻工业学院３００２２２）ＳｔｕｄｙｏｎｔｈｅＫｎｏｔｏｎｔｈｅＭａｒｇｉｎｏｆＧｌａｓｓｗａｒｅ￥ＺｅｎｇＸｉａｏｙｕ；ＺｈａｎｇＪｉａｎｇｕｏ；ＸｕＨｏｎｇｆｕ（ＴｉａｎｊｉｎＩｎｓｔｉｔｕｔｅｏｆ...     

Knotted Proteins under Tension

We study the behavior of two knotted proteins under stretching by a constant force within a coarse-grained structure-based model. One protein, with the structure code 1J85, has a knot that is deep and another, 2ETL, has a knot that is shallow. We demonstrate that tightening of the deep knot may take place before the ultimate end-to-end distance is achieved. However, as with proteins without knots, we observe the existence of a crossover between the low- and high-force regimes of the dependence of the mean unfolding time (as defined through properties of the end-to-end distance) on the applied force. We find little correlation between the unfolding time and the final placement of the tightened knot. We also consider the novel mechanical protection strategy in the single-molecule force spectroscopy of host-guest fusion proteins. We find that it should be useful in studies of guest proteins with knots in the constant-speed mode. However, at constant force, its usefulness is limited if the mechanostability of the host is larger than that of the guest molecule.     

三色PP-BCF的均匀混色技术探讨

在国产膨体纱(BCF)设备上,增加预网络器和混丝罗拉,通过主网络装置改造和工艺优化,生产出混色均匀的三色丙纶-膨体纱(PP-BCF).结果表明:改进主网器装置,调整主网络器压力0.45～ 0.60 MPa,网络器前张力100～ 150 cN,卷绕张力150 cN,试制的三色PP-BCF网络节均匀,网络节为(25±3)个...     

Ultra-stable peptide scaffolds for protein engineering-synthesis and folding of the circular cystine knotted cyclotide cycloviolacin O2

The cyclic cystine knot motif, as defined by the cyclotide peptide family, is an attractive scaffold for protein engineering. To date, however, the utilisation of this scaffold has been limited by the inability to synthesise members of the most diverse and biologically active subfamily, the bracelet cyclotides. This study describes the synthesis and first direct oxidative folding of a bracelet cyclotide-cycloviolacin O2-and thus provides an efficient method for exploring the most potent cyclic cystine knot peptides. The linear chain of cycloviolacin O2 was assembled by solid-phase Fmoc peptide synthesis and cyclised by thioester-mediated native chemical ligation, and the inherent difficulties of folding bracelet cyclotides were successfully overcome in a single-step reaction. The folding pathway was characterised and was found to include predominating fully oxidised intermediates that slowly converted to the native peptide structure.     

几种杀线剂对番木瓜根结线虫病的防效

研究选用了7种药剂对番小瓜根结线虫进行大田防效试验,结果表明：所有参试药剂的各参试浓度对番木瓜根结线虫的防效均极显著高于空白对照,其中10％噻唑磷GR、5％丁硫克百威GR、1．5％二硫氰基甲烷WP对番木瓜根结线虫的防治效果显著高于其它药剂,且持效性较好。     

Protein stabilization in a highly knotted protein polymer

The polypeptide backbones of a few proteins are tied in a knot. The biophysical effects and potential biological roles of knots are not well understood. Here, we test the consequences of protein knotting by taking a monomeric protein, carbonic anhydrase II, whose native structure contains a shallow knot, and polymerizing it end-to-end to form a deeply and multiply knotted polymeric filament. Thermal stability experiments show that the polymer is stabilized against loss of structure and aggregation by the presence of deep knots.     

Knot,Heartwood, and Sapwood Extractives Related to VOCs from Drying Southern Pine Lumber

Abstract

The presence of knots or heartwood influences the amount and composition of volatile organic compound (VOC) emissions associated with drying of southern pine lumber. Experimental kiln charges of lumber containing 0 to 5% of knot volume gave VOC emissions ranging from 2.86 to 4.25 lb of carbon/dry ton of wood. Studies of emissions from sapwood and knots showed that knots contain about ten times the amount of volatile terpenes found in sapwood. Consequently half of the total volatile emissions would come from 5% of knot volume in sapwood. However, correlation coefficients of knot frequency or volume with VOC emissions obtained from experimental kiln studies were only 0.57 and 0.51, respectively. Southern pine heartwood contains about five times the amount of volatile terpenes found in sapwood and more of the volatile compounds present in heartwood are emitted than from knots. Therefore, small variations in the amount of heartwood result in large changes in VOC emissions in drying southern pine lumber.