焙烧介质和工艺参数对硅质制品性能和相组成的影响

本文研究了焙烧气体介质和其它工艺因素对硅砖性能及其中氧化硅转化程度的影响。根据试样相组成和性能的对比分析结果，推荐以下参数作为使用干矿化剂的硅砖最佳制造工艺参数：硅石颗粒尺寸不大于２ｍｍ；成型压力不低于５００ＭＰａ，烧成温度１４２０℃。根据岩相研究和Ｘ射线照相研究表明，硅砖在还原介质中焙烧是最好的，它能促进硅砖中石英更完全转化并保证硅质制品具有很高的使用性能。     

使用干矿化剂生产硅质制品

在生产硅质制品时,为了使硅石颗粒结合成整体料,同时为了加速石英向高温晶型(方石英、鳞石英)转化,往配料中加入各种矿化剂。在没有矿化剂的情况下,会发生干转化,结果硅砖的体积膨胀很大,组织松疏。 实践中,最普遍采用的矿化剂是石灰铁质     

梅钢焦炉用后硅砖显微结构分析

显微结构分析表明:焦炉炭化室用后硅砖中或多或少存在残余石英,而燃烧室由于温度较高,其硅砖中的石英逐渐经亚稳方石英转变为鳞石英.焦炉用后硅砖的相变过程只限于石英和亚稳方石英的转化,随着石英和亚稳方石英逐渐转变成鳞石英,硅砖结构趋于稳定.炭化室用后硅砖表面出现碳沉积并石墨化,对硅砖起到保护作用,并有利于提高炭化室的热导率.     

盐酸催化氧化法生产氯气

本文叙述用 Shell 法,将 HCl 催化转化成Cl,空气与 HCl 进入一台流动床催化反应器的底部,反应温度365℃。从流动床中脱离出来的催化剂颗粒,在一台高效旋风分离器中分离出来,然后再加到反应器中去、使离开反应器的热气体立即急冷,在文氏涤气机中用循环 HCl 水溶液流进行洗涤。经急冷后的气体在一台吸收塔中进行绝热吸收,H_2O 从塔顶进入,以除去未转化 HCl 气的最后痕迹。从吸收塔出来的 HCl 水溶液进入一个解吸塔,在此中气体 HCl 被回收而循环回到反应器。从解吸塔出来的淡的 HCl 水溶液流循环回到吸收塔和急冷系统。已脱除 HCl 的气体进入     

玻璃池窑大(石旋)保温问题的探讨

大(石旋)保温可减少热损耗10～15%,是提高熔窑热效率的重要途径。大(石旋)保温的关键问题是硅砖质量和提高砌筑质量。提高硅砖质量不仅要保证化学成分,而且要通过组织适当的原料颗粒配比,添加适量的矿化剂,使硅砖充分烧结和鳞石英转化,从而提高硅砖的荷重软化温度。     

高导热硅砖在焦炉上的应用

为了探讨高导热硅砖在焦炉上的节能效果,从物理性能和显微结构等方面阐述了高导热硅砖的特点,计算了采用高导热硅砖时燃烧室的温度,介绍了高导热硅砖的实际使用情况。结果表明:相比普通硅砖,高导热硅砖的气孔孔径小,致密度高;在炭化室热工参数不变的前提下,使用高导热硅砖时燃烧室内火焰温度可以降低约41℃;实际应用显示,在焦炉炭化室炉墙砌筑高导热硅砖可以带来可观的经济效益,同时能减少有害气体排放。     

MgO-ZrO2-C材料的性能和显微结构

研究了在MgO-C耐火材料中添加单斜氧化锆或锆英石所形成的MgO-ZrO2-C材料的性能和显微结构.结果表明(1)加入单斜氧化锆和锆英石导致材料的高温抗折强度降低.(2)热震温度低于1000 ℃时,加入不同量的单斜氧化锆或锆英石对材料抗折强度损失率的影响较小;而热震温度为1200 ℃时,不同的添加量有较大的差别,当单斜氧化锆的添加量为5%～7%,锆英石的添加量为1.54%时,MgO-ZrO2-C材料的抗折强度损失率最小.(3)添加的单斜氧化锆在1200 ℃的热震温度下有部分ZrO2固溶到了镁砂颗粒的内部;而添加的锆英石在1200 ℃下变化轻微,但在1400 ℃下,材料中仅存在少量未分解或分解不完全的锆英石,MgO由基质向锆英石颗粒内部扩散,导致分解完全的锆英石颗粒转变为ZrO2、CMS和c- ZrO2小颗粒.     

锆英石热分解的实验研究

在碳管炉内进行了锆英石热分解的实验研究．讨论了温度、颗粒和添加剂（MgO、CaO等）对锆英石热分解的影响低温区（≤1700℃）的锆英石分解是受化学反应速度控制，表现反应级数为零级，表观活化能为585．0kJ／mol，用动力学方程能较好地解析低温区的锆英石热分解反应，高温区（＞1700℃）主要是SiO（g）等气体通过反应层的扩散来控制，锆英石的热分解也受粒度的影响，颗粒越细，其分解率越大，加入MgO、CaO和Al2O3等能促进锆英石的热分解     

硅砖中α-方石英的晶体结构与形貌

利用光学显微镜、扫描电镜和X射线衍射仪研究了几种不同状态硅砖的晶体形貌和晶格常数.结果表明:经1 350 ℃煅烧72 h,1 450℃再煅烧3 h的块状结晶石英岩,70%的石英已转化为微晶方石英.1430～1 450℃经48～72 h烧成未用的硅砖主相为鱗石英和方石英,并有少量残留石英.经＜1250℃使用15年的硅砖主相为鱗石英和方石英,已不见残存石英.经1 550～1600℃使用3年的硅砖的稳定相只有α-方石英,其晶格常数为:a0=0.496 95 nm;c0=0.692 50 nm,形成的方石英都具有标准的晶格构造,粒状酷似八面体的四方双锥,未见正三角形晶粒.     

锆英石-莫来石复合材料的热机械行为

锆英石-莫来石复合材料是通过锆荚石粉和莫来石粉反应烧结而制得的。热机械性能（强度和韧性）是通过莫来石和锆英石间的中间相体现出来的。这种复合材料在室温与1000℃之间表现出较好的热震稳定性，在1100℃与1300℃温度区域，将压力由10MPa增加至90MPa来衡量材料的弯曲蠕变。在1000℃与1300℃范围内，当活化能从280kJ·mol^-1增加至900kJ·mol^-1，材料的应力指数在2和3之间变化。从微观结构分析可以看出晶粒间的蠕变机理。莫来石颗粒与锆英石颗粒之间的界面力比锆英石颗粒间的力要重要的多。在锆英石基体中形成莫来石颗粒。可以使材料同时具有莫来石材料的良好的蠕变性能和锆英石材料良好的热震稳定性。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外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、聚苯乙烯、聚氯乙烯、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、聚氨酯、不饱和聚酯树脂、环氧树脂)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.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外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生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。