压力变送器在化工领域的选型与应用

压力变送器的选型包括变送器的类型、材质、量程、防爆性能等多个方面,合理的选型不仅可以确保变送器的使用寿命,更能保障化工生产过程中的各流程得以稳定开展。变送器的选型受到诸如环境条件、应用工况、安装条件、介质特性与经济效益等各方面的影响。简要分析了变送器的选型及其在化工领域的应用。     

硅微电容智能型变送器在化工生产中的应用

对化工生产中常用的硅微电容智能型变送器的结构特点、工作原理、安装调试以及故障处理等进行阐述,并结合化工生产实际应用操作情况,分析了硅微电容智能型变送器的优劣,为化工生产一线的仪表技术人员提供借鉴。     

气动双法兰差压变送器

在几年试生产气动单法兰差压变送器的基础上,我厂于72年接受原燃化部气动双法兰差压变送器试制任务。在院系厂党组织的领导下,在有关单位的大力支持下,全厂以批林整风为纲,经全体职工的共同努力,反复试验,终于在73年上半年基本完成了气动双法兰差压变送器的试制工作,并将后一批样机送到北京有机化工厂、北京化工实验厂、北     

关于变送器的正反作用

随着化工自动化水平的不断提高以及控制系统的日益多样化和复杂化,提出了变送器的正反作用问题。变送器的正反作用我们可以这样定义:当变送器的被测参数增大时,其输出信号也增大的,称为正作用变送器,其输出信号减小的,则称为反作用变送     

化工设计中罐区的仪表选型分析

对化工设计中罐区的主要仪表类型、储罐液位仪表选型进行了阐述,具体分析了常压罐和无压罐使用的单法兰液位变送器和差压变送器。     

化工行业中压力变送器的选型及应用

压力变送器的类型、材质、量程、防爆等级等的选择与环境条件、应用工况、安装条件、介质特性、经济性等息息相关,变送器的合理选型可更好地保证变送器的使用寿命并确保化工生产过程的测量控制稳定。     

防氯碱腐蚀压力变送器通过鉴定

吉林化工仪表厂研制的防腐压力变送器于今年5月通过技术鉴定。此变送器是DDZ—Ⅲ型变送单元中化工专用仪表。它可不用隔离液,F_4或F_(46)作隔膜片。直接测量氯气、碱液、盐酸、硫酸、硝酸等强腐蚀介质的压力。经沈阳化工厂、吉林电石厂、     

浅谈压力变送器选型中需注意的几个问题

压力变送器的量程、精度选择是变送器选型中的一个重要内容,微压与微差压变送器尤为特殊,本文论述了选型时需注意的几个问题,应做到的几个要点,以便能选型出精度最高、性能最佳的变送器。     

工程设计中热电阻的选型设计

介绍了化工工程设计中热电阻选型时的主要参数如测量元件结构形式、测量元件数量、标准分度号、允许精度等级、测量元件结构形式、仪表量程和变送器校验量程、外保护套管结构形式等应该如何选取;比较了热电阻和一体化温度变送器各自的优缺点,选型时如何根据实际情况进行选择;给出热电阻的几种典型安装连接形式;最后详细介绍了保护套管插入深度的计算方法。对工程设计人员起到一定的参考作用。     

法兰变送器在化工测量中的调试应用

论述了法兰变送器在化工测量中的调试应用,针对性提出调试和使用过程中的独到经验和技术结晶.     

2010～2011年世界塑料工业进展

收集了2010年7月～2011年6月世界塑料工业的相关资料,介绍了2010～2011年世界塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚氯乙烯、聚苯乙烯、ABS树脂),工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚),特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮),通用热固性树脂(酚醛、不饱和聚酯树脂、环氧树脂、聚氨酯)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍。     

Mechanisms Governing Anaphylaxis: Inflammatory Cells,Mediators, Endothelial Gap Junctions and Beyond

Anaphylaxis is a severe, acute, life-threatening multisystem allergic reaction resulting from the release of a plethora of mediators from mast cells culminating in serious respiratory, cardiovascular and mucocutaneous manifestations that can be fatal. Medications, foods, latex, exercise, hormones (progesterone), and clonal mast cell disorders may be responsible. More recently, novel syndromes such as delayed reactions to red meat and hereditary alpha tryptasemia have been described. Anaphylaxis manifests as sudden onset urticaria, pruritus, flushing, erythema, angioedema (lips, tongue, airways, periphery), myocardial dysfunction (hypovolemia, distributive or mixed shock and arrhythmias), rhinitis, wheezing and stridor. Vomiting, diarrhea, scrotal edema, uterine cramps, vaginal bleeding, urinary incontinence, dizziness, seizures, confusion, and syncope may occur. The traditional (or classical) pathway is mediated via T cells, Th2 cytokines (such as IL-4 and 5), B cell production of IgE and subsequent crosslinking of the high affinity IgE receptor (FcεRI) on mast cells and basophils by IgE-antigen complexes, culminating in mast cell and basophil degranulation. Degranulation results in the release of preformed mediators (histamine, heparin, tryptase, chymase, carboxypeptidase, cathepsin G and tumor necrosis factor alpha (TNF-α), and of de novo synthesized ones such as lipid mediators (cysteinyl leukotrienes), platelet activating factor (PAF), cytokines and growth factors such as vascular endothelial growth factor (VEGF). Of these, histamine, tryptase, cathepsin G, TNF-α, LTC₄, PAF and VEGF can increase vascular permeability. Recent data suggest that mast cell-derived histamine and PAF can activate nitric oxide production from endothelium and set into motion a signaling cascade that leads to dilatation of blood vessels and dysfunction of the endothelial barrier. The latter, characterized by the opening of adherens junctions, leads to increased capillary permeability and fluid extravasation. These changes contribute to airway edema, hypovolemia, and distributive shock, with potentially fatal consequences. In this review, besides mechanisms (endotypes) underlying IgE-mediated anaphylaxis, we also provide a brief overview of IgG-, complement-, contact system-, cytokine- and mast cell-mediated reactions that can result in phenotypes resembling IgE-mediated anaphylaxis. Such classifications can lead the way to precision medicine approaches to the management of this complex disease.     

Fireclay Refractory Bricks for Hot Blast Stove

This standard specifies the classification, shape, dimension, technical requirements, test method, inspection rules, packing, marking, transportation, storage and quality certification of fireclay refractory bricks for hot blast stove.     

Hydrocarbon components of the yellowheaded spruce sawfly sex pheromone

The primary sex pheromone of the yellowheaded spruce sawfly,Pikonema alaskensis (Rohwer) (Hymenoptera: Tenthredinidae), was found to include a series of straight-chain hydrocarbon dienes, all with the double bonds in the 9 and 19 positions and all with the (Z, Z) configuration. The major components, of 29, 31, 33, 35, and 37 carbon atoms, were synthesized. In the field and the greenhouse, the synthetic dienes were far above control levels in activity but, at least during the first hours of bioassay, were somewhat less active than the female-derived materials on a weight basis. In the field, a mixture of all five synthetic dienes, in the proportions found in the females, was more attractive than any single one, on a mole basis. In addition, (Z, Z)-9,19 dienes of 28, 30, 32, 34, 36, 38, and 39 carbons have been detected in females in minor amounts. The first five were bioassayed, and each was found to be similar in activity to the 35-carbon component when compared on a weight basis. The synthetic dienes, while active by themselves, were strongly synergized by two, more polar, Florisil fractions derived from females. Experimental design considerations are discussed.     

中低温煤焦油蒸馏过程中金属元素的迁移规律

以中低温煤焦油轻油和重油为实验原料,采用常压蒸馏获得170~200℃、200~240℃、240~270℃、270~300℃、300~320℃、320~340℃、340~360℃和360~390℃煤焦油馏分油;利用配有油品加氧制冷进样系统的ICP-OES测定了21种微量元素在馏分油中的含量,考察了不同馏分油中元素的分布情况。研究表明：在原煤焦油中,未发现Ag、Mg、Mo、Na、Ni、Fe、Mn、Cr及Ti元素,含量较高的元素有Sn、P、Al、Pb、Si,其中Sn元素在轻油和重油中的含量分别为11.78μg/g和14.04μg/g;在所有馏分油中,未发现Al、Mo、Fe、Mn、Cr及Ti元素,含量比较高的元素有Si、Sn、Na、Zn、Pb,特别是Si、Na、Sn、Zn、Ni、Pb及B元素可以有效富集于馏分油中。可能的原因是Ca、Fe、Mg、Al等金属以不同的盐类形态存在,在煤焦油脱水及<170℃蒸馏过程中,这些金属盐类会被部分带出,导致其在馏分油中的含量未富集或未检出;通过关联金属元素在馏分油中的分布与其组成的关系,馏分油中元素的分布可能与酚类化合物、杂环化合物和蒸馏温度等相关。酚类化合物及杂环化合物可能与Ag、B、Cu、Mo、Sn、Na、Zn、Ca、Pb等金属形成络合物或卟啉配合物,蒸馏温度一方面可以破坏Sn、Cd、Pb、Zn、Cu、Ca、Pb等元素在馏分油中的结合力,另一方面也可以促进这些元素与馏分油中的含氧、含氮等化合物更好地发生化合反应,进而影响金属元素在馏分油中的含量分布。     

陶瓷名物探源二则

匋、陶、窑(窯)上古皆读成舌头音,意义又相通,实际为一个意义上先后产生的几个形体不同的字,先民以陶(匋)既称呼窑灶,又指窑灶出品之物,又指制作陶器;坏(坯)、瓶、瓬、瓿、甂、缶、钵、皿、杯(盃)、盆(瓫)均指窑灶所出之物或后世模仿窑灶出品之物,其字皆由重唇音演变而来,亦为同胞兄弟的同源词。     

铋系半导体光催化剂研究进展

铋系半导体材料具有特殊的层状结构以及合适的带隙,具有良好的可见光响应能力以及稳定的光化学特性,作为一类新型的环境友好型光催化剂在环境修复与解决能源危机等领域受到广泛关注,已成为近年来的研究热点。然而,铋系半导体光催化剂距离实际大规模应用仍存在一些亟需解决的问题,如光生载流子复合率高、对可见光谱的响应范围有限、光催化活性较差、还原能力较弱等。本文首先介绍了铋系半导体材料的典型特征、制备方法与反应机理,在此基础上着重阐述了铋系半导体光催化在形貌调控、构建异质结、离子掺杂、碳质材料掺杂、贵金属沉积、染料敏化等改性手段的研究进展以及在降解水体污染物、杀菌消毒、空气净化、制氢、还原CO2、有机合成等领域的应用成果。最后对铋系半导体光催化剂的未来前景做出展望,指出其未来的研究方向应致力于从多手段耦合改性、拓展其应用领域以及深入探究反应机理等方面开展。     

抗菌防腐剂（Ⅰ）—抗菌防腐剂的历史、定义与分类

简要回顾了抗菌防腐剂的发展历程,进一步明确了杀菌剂,抑菌剂,抗菌剂,防腐剂,防霉剂,消毒剂,杀生剂,保鲜剂,抗生素的概念。同时,结合抗菌防腐剂的发展在对抗菌防腐剂按无机物,有机物和天然物分类的基础上,进一步又按化学结构和官能团将抗菌剂分为有机金属,有机卤代物,醇,酚,醚,醛,酮,醌,酸,酯,含氮类,含硫类,有机磷,有机砷类以及杂环类等。     

典型过程强化技术在纳米材料制备中的应用进展

纳米材料被誉为21世纪的新材料,广泛应用于化工、电子、国防、陶瓷等领域.传统的纳米材料制备方法面临粒径控制较困难、批次间重复性差,存在放大效应等不足.过程强化技术是化学工程学科的研究前沿和热点方向之一,旨在通过在生产过程中采用新工艺、新设备等手段,实现缩减操作单元、减小设备体积、提高生产能力及能量利用效率的目的,是实现...     

Low-molecular weight organic compositions of acid waters from vegetable oil soapstocks

Alkaline extracts (soapstocks) from canola, corn, cottonseed, peanut, soybean, and sunflower oil refining were acidified, and identities and concentrations of the low-molecular weight organic components of the resulting acid waters were determined by gas chromatography, followed by mass spectroscopy, and by high-performance liquid chromatography. The main components of each acid water sample, in order of decreasing concentration and after omitting the fermentation product lactic acid, were phosphoric acid, α-glycerophosphate, and glycerol from canola;myo-inositol, phosphoric acid, α-glycerophosphate andmyo-inositol-1-phosphate from corn; glycerol, α-glycerophosphate,myo-inositol-1-phosphate, and β-glycerophosphate from cottonseed; phosphoric acid, glycerol, andmyo-inositol from peanut; α-glycerophospho-1-myo-inositol,myo-inositol-1-phosphate, α-glycerophosphate, and glycerol from soybean; and α-glycerophosphate, glycerol,myo-inositol-1-phosphate, and β-glycerophosphate from sunflower.