亚硝酸钙阻蚀剂的耐腐蚀试验和评价

佩奇(Page)和屈大维(Treadaway)曾报导,饱和 Ca(OH)_2溶液中获得的极化结果类似于水化后的普通波特兰水泥浆。图1a表明该研究中测得的饱和 Ca(OH)_2溶液中钢材的腐蚀行为。     

植物病害化学防治概念的演变

预测植物病害化学防治的未来,任何人似乎都很有信心。然而,现在在探索新的杀菌剂研究中所有效进行的工作,都是在计划新的研究战略,希望从中能产生下一代的防治措施。发现、开发和登记新的农药品种所需的漫长时间和巨大费用,迫使工业界采取稳健的研究开发模式,它对新产品的成功率具有显著的影响力,因此任何时候,试验方法或程序只能作细微的变化,所以说新农药发现的原则的变化几乎是不可理解和预知的。     

悬浮法聚氯乙烯形态学的发展及重要性

目前,每生产一大批聚合物都必须加以精心的控制,使其具有一定的特性,以确保产品的商业生存能力,其它一些聚合物,也许会涉及到分子量的分布,结晶速     

苯甲酰基苯基脲杀虫剂

取代苯基脲化合物的生物活性已经知道相当长一个时期了,很多众所周知的除草剂就属于这一类。而取代苯甲酰脲类化合物的杀虫活性只是在1970年前后才被Philips-Duphar公司所发现。在除草剂敌草腈结构活性研究过程中,把敌草腈与敌草隆相结合,得到1-(2,6-二氯苯甲酰基)-3-(3,4-二氯苯基)脲,代号为Du 19,111。此化合物没有显     

Effects of feed withdrawal before delivery on pork quality and carcass yield

A total of 270 pigs from a Yorkshire/Duroc/Landrace 3-way cross, reared under an ad libitum feed regimen, were delivered for slaughter after fasting (with access to water) for 24 and 0 h (Exp. 1), 16 and 0 h (Exp. 2) and 24, 16 and 0 h (Exp. 3). The interval between delivery and slaughter was 4-5 h. Feeding until delivery resulted in a lower pH at 45 min post mortem in the longissimus muscle. Ultimate pH values of longissimus and semimembranosus muscles were higher after feed restriction for 24 h. However, the incidence of dark, firm and dry (DFD) (pH > 6·2) was also increased after fasting in Exp. 1. Assessment of meat quality in samples taken from the longissimus at 20 h post mortem showed that, in comparison with feeding until delivery. Hunter L(?) (Lightness)-values and drip loss decreased and firmness improved by prolonged fasting (24 h). Fasting for 16 h did not reduce drip loss, but colour was improved (lower Hunter L(?)-values) in Exp. 3, although not in Exp. 2. Feeding until delivery resulted in better meat quality in Exp. 2 than in Exp. 1 and 3. A significant reduction in dressing percentage as a result of fasting was only found in Exp. 1. There appears no economic disadvantage in restricting feed for 16 h prior to delivery. Although the incidence of DFD may also increase, a fasting period of 16-24 h is recommended to reduce pale, soft and exudative (PSE) muscle, while losses in carcass yield are minimized. Other advantages of fasting are discussed.     

Efficient analysis tool for coupled-SAW-resonator filters

The advantages of the coupled-mode (COM) formalism and the transmission-matrix approach are combined in order to create exact and computationally efficient analysis and synthesis tools for the design of coupled surface acoustic wave resonator filters. The models for the filter components, in particular gratings, interdigital transducers (IDTs) and multistrip couplers (MSCs), are based on the COM approach that delivers closed-form expressions. To determine the pertinent COM parameters, the COM differential equations are solved and the solution is compared with analytically derived expressions from the transmission-matrix approach and the Green's function method. The most important second-order effects, such as energy storage, propagation loss, and mechanical and electrical loading, are fully taken into account. As an example, a two-pole, acoustically coupled resonator filter at 914.5 MHz on AT quartz is investigated. Excellent agreement between theory and measurement is found.     

铝电解槽烟气干法净化—新型气/固反应器的设计和运行特性

序言干法净化电解车间烟气用的氧化铝,吸附有烟气中的杂质。如很细的金属化合物粒子、二氧化硫和由阳极带入的碳素材料。当净化器捕集的氧化铝返回电解槽时,这些固体杂质也进入电解槽,其中有的成份能使铝的纯度降低。如果生产用的氧化铝百分之百用于净化,这些     

球铁中干扰元素Sb和Mg、Ce的相互作用

本文用带能谱仪(EDAX9100)的扫描电镜(SEM505),对球铁中的微粒进行微区定量分析,以研究球铁中干扰元素Sb和Mg、Ce的相互作用。结果发现:Sb和Mg形成高熔点化合物Mg3Sb2,使铁水中游离Mg原子减少,因此引起球化衰退:Ce能和Sb形成熔点更高的化合物Cesb,从铁水中清除Sb原子,从而中和了Sb的有害影响。     

欧洲对聚合物淬火剂的看法

在欧洲合成淬火剂或聚合物淬火剂用于铁合金和有色合金热处理工业已有30年左右的时间了,其使用范围从感应淬火到钢丝索氏体化处理。最早的合成淬火剂是聚乙烯醇(PVA),在日益增加的感应淬火中,它用     

On ADRC for non-minimum phase systems: canonical form selection and stability conditions

Active disturbance rejection control (ADRC), as proposed by Prof. Jingqing Han, reduces first the plant dynamics to its canonical form, normally in the form of cascade integrators, for which the standard controller can be employed to meet the design specifications. This paper concerns with the selection of the canonical form for non-minimum phase systems. In particular, it is shown that, by employing the well known controllable canonical form, the uncertainties of such systems can be divided into two terms in the state space model, one in the control channel and the other in the output channel. The necessary and sufficient condition is obtained for the stability of the closed-loop system with the proposed canonical form and ADRC. Also, by showing the necessity of the detectability of the extended system as well as certain information of the systemˉs “zeros”, we present the fundamental guidelines of design ADRC for non-minimum phase uncertain systems.