镀锌层三价铬蓝白钝化工艺的研究

三价铬蓝白钝化对环境污染小,但钝化液成分较复杂,钝化膜耐蚀性及外观不如六价铬钝化膜.为此,本文探讨了工艺参数对钝化层外观和耐蚀性的影响,并得到了组分简单的镀锌层三价铬蓝白钝化工艺.钝化膜耐蚀性能好,经84 h的中性盐雾试验不产生白锈.     

氯化铬对热镀锌板三价铬钝化膜的影响

采用中性盐雾试验、醋酸铅点滴试验以及电化学极化和阻抗测试方法,研究了不同浓度的氯化铬对热镀锌板三价铬钝化膜耐蚀性能的影响;采用金相显微镜观察了钝化膜极化后的腐蚀形貌。研究表明,钝化膜中以Cr Cl3·6H2O为主要成膜物,当浓度在0.6~1.0 mol/L时,钝化膜耐中性盐雾试验和醋酸铅点滴时间最长,在3.5%Na Cl溶液中腐蚀电流最小、低频阻抗值最大,并分析了氯化铬浓度对钝化膜耐蚀性的影响。     

镀锌层三价铬蓝白色钝化工艺的研究

由于六价铬的高毒性,镀锌层三价铬钝化工艺是一种替代六价铬钝化工艺的良好选择.其中三价铬蓝白钝化是一种优良的防护-装饰性膜层.详细阐述了影响蓝白色钝化膜性能的主要因素.经过不断的试验,研究出了一种组分简洁的镀锌层三价铬蓝白色钝化液,性能稳定,外观和耐蚀性优良.     

影响热镀锌板三价铬钝化膜质量的因素及改进措施

针对某冷轧厂生产的三价铬钝化热镀锌板耐蚀性差的问题,从微观特征与钝化工艺方面对钝化膜质量进行研究。发现钝化膜质量与膜中Cr化合物的含量正相关,致密性越好则耐蚀性越好,而且钝化膜厚度及其均匀性与带钢运行速率、基板厚度、钝化涂覆辊辊间压力等参数有密切关系。从钝化液浓度、基板粗糙度、涂覆辊辊间压力、钝化辊辊面质量等方面对钝化工艺进行优化,钝化膜质量得到明显改善,72 h中性盐雾试验合格率达到95%以上。     

电镀锌层无铬钝化工艺的研究

开发一种绿色无铬的钝化工艺,所得钝化膜的性能接近铬酸盐钝化膜的。研究了电镀锌层在钛磷硅钼复合体系中的钝化工艺,并采用扫描电子显微镜、硫酸铜点滴实验和中性盐雾实验等方法测试了钝化膜的形貌和耐蚀性。通过正交实验确定了钝化液的最优配方为:三氯化钛10mL/L,磷酸1.8mL/L,硅酸钠18g/L,钼酸钠0.85g/L。其中硅酸钠的质量浓度对钝化膜的表面形貌及耐蚀性的影响最大。采用二次钝化工艺能有效提高钝化膜的耐蚀性。采用上述配方和工艺能够得到一种淡蓝色的无铬钝化膜,其耐蚀性优于三价铬钝化膜的,硫酸铜点滴时间能达到80s,中性盐雾实验的变色时间为72h。     

新型三价铬钝化技术

概述了镀锌三价铬钝化的发展历程。叙述了三价铬钝化的机理。介绍了一种新型三价铬钝化液的组成。该钝化液采用含有纳米微粒的封孔剂。通过NSS试验发现,当2种不同封孔剂配合使用时,膜层耐蚀性大大提高。对该三价铬钝化的使用方法与工艺特点,pH、温度及时间的控制,封闭剂的特点进行了简单介绍。提出应用于三价铬钝化前的碱性无氰镀锌及酸性镀锌的适用场合。使用该钝化工艺后,膜层耐蚀性达到甚至超过六价铬钝化工艺。     

高性能无铬钝化技术

介绍了ZECCOAT无铬钝化工艺.该工艺采用了高科技纳米技术,钝化液无毒,钝化膜薄且具有自修复性,钝化产品的耐蚀性高.生产实践表明:ZECCOAT无铬钝化的成本与传统三价铬钝化加封闭工艺的大体相同.中性盐雾试验结果表明:采用三价铬钝化+ ZECCOAT无铬钝化与直接采用ZECCOAT无铬钝化相比较,产品的耐蚀性得到了明显的提高.     

三价铬钝化膜为什么会产生六价铬

根据三价铬和六价铬的氧化还原性质,指出在碱性介质中三价铬可以被氧气氧化成六价铬,认为三价铬钝化膜中三价铬的存在形式(某种三价铬的碱式盐)是其在空气中放置时三价铬被氧化为六价铬的内在原因.提出了采用无铬钝化工艺,钝化后封闭及加强三价铬钝化工艺管理和钝化产品的存放管理等应对措施.     

镀锌层三价铬彩色钝化工艺研究

通过正交试验研制了一种镀锌层三价铬彩色钝化液,并确定了钝化工艺条件.研究中采用盐雾试验、电化学测试和金相显微镜对所得三价铬钝化膜进行了测试和观察,结果表明:该三价铬钝化膜具有色彩鲜艳、成膜均匀、耐蚀性能优良等特点.     

低碳钢热镀锌层三价铬钝化工艺研究

采用三价铬加封闭技术对Q195低碳钢热镀锌板进行了钝化处理,通过中性盐雾试验测试了其耐蚀性。采用X-射线衍射仪对膜层成分进行了测试,采用扫描电镜观察了膜层的表面形貌。结果表明,钝化膜具有良好的耐腐蚀性能,与Cr(Ⅵ)钝化膜层耐腐蚀性能相当,钝化膜中不含Cr(Ⅵ)成分。     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

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.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

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

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。     

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.