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利用机械密封的优点和特性,对原来的浆料槽填料密封结构进行了改造,消除了泄漏,降低了噪声,减少了振动,改善了环境,且便于维护和检修,降低了检修人员的劳动强度和检修费用,设备的技术含量得到了提升。 相似文献
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带式过滤机在多品种氢氧化铝生产中的应用 总被引:1,自引:0,他引:1
介绍了带式真空过滤机的工作原理及其在多品种氢氧化铝生产方面的应用情况,并对带式真空过滤机使用过程中存在的问题进行了改造。改造之后,提高了洗涤过滤效率,降低了滤饼水分,降低了能耗,提高了产量,确保了产品质量,取得了较好的经济效益。 相似文献
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在两步法三聚氰胺工艺生产中,由于热气过滤单元温度高,产出的粗品三聚氰胺纯度低,副产物多,需要在精制过程中利用蒸汽,重新加热溶解粗品三聚氰胺,并送入结晶塔降温结晶,得到纯度高的三聚氰胺成品,此过程消耗了大量的蒸汽,增加了生产成本。提出了一种新的生产工艺,首次在二步法三聚氰胺工艺中增加了热气冷却单元,降低了热气温度,并副产了部分蒸汽,分离出了高沸点反应副产物,净化了热气,得到了纯度高的粗品三聚氰胺,同时改变了精制工艺,极大地降低了蒸汽消耗,节约了生产成本,提高了产品市场竞争力。 相似文献
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分析了三氯氢硅生产过程中水冷器堵塞严重的原因,介绍了湿法除尘技术在三氯氢硅行业中的研究和应用.湿法除尘技术的应用有效地解决了冷凝系统的堵塞问题,使得整个生产系统实现长期稳定运行,不仅提高了生产效率,降低了生产成本,解决了频繁拆洗水冷器造成的现场污染,改善了工作环境,降低了劳动强度,同时杜绝了安全隐患. 相似文献
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同志们:第十五次秘书长工作会议经过几天紧张的活动,今天就要结束了。几天来,各专业分会和地方协会的秘书长同志们,聚集一堂,认真地总结了去年协会的工作,研究橡胶行业当前的形势,交流了今年协会工作的设想,讨论了协会工作中的一些实际问题。会议交流了经验,统一了认识,协调了工作,明确了方向,为今年协会工作的开展打下了良好的基础。会议开得很好,达到了预期的目的。各分会和地方协会工作人员尤其是秘书长,去年为缓解行业困难,促进行业发展,做了大量艰苦的工作,付出了辛勤的劳动,作出了很大的贡献,我代表总会对大家表示… 相似文献
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阐述了一种煤制甲醇加碱工艺的技术改进,解决了国内现有工艺技术弊端,降低了设备投资,缩小了占地面积,减少了操作人员劳动强度,减轻了环境污染,并通过了三年多的生产运行验证。 相似文献
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介绍了聚合釜电动底阀的结构和特点,分析了电动底阀存在的问题,并进行了改造,降低了设备的故障率,节约了维护成本,提高了产品产量。 相似文献
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It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples. 相似文献
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M. S. J. Simmonds W. M. Blaney F. Delle Monache M. Marquina Mac-Quhae G. B. Marini Bettolo 《Journal of chemical ecology》1985,11(12):1593-1599
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. 相似文献
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Cheng-Le Zhao Shane Porzio Alan Smith Haiyan Ge H. T. Davis L. E. Scriven 《Journal of Coatings Technology and Research》2006,3(2):109-115
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. 相似文献
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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. 相似文献
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ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究 总被引:15,自引:0,他引:15
建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。 相似文献
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