镀银件腐蚀变色及保护

分析了镀银件产生变色的原因,并通过试验研究了经各种保护处理的镀银件在腐蚀性介质哪ＳＯ２和Ｈ２Ｓ日光和紫外线等照射下的变色情况。提出了选择镀银件保护材料应满足的要求。     

氰化物镀银液中光亮剂行为的初步探讨

采用线性电位扫描法，扫描电镜技术（ＳＥＭ），俄歇能谱（ＡＥＳ）及Ｘ－ｒａｙ衍射（ＸＲＤ）技术，初步研究了光亮剂的加入对镀银层粒度，晶面取向，含杂状况的影响，结果表明ＦＢ－１，使结晶细致。这两种光亮剂的，工不使层的内部有夹杂现象，ＦＢ－１，ＦＢ－２光亮剂混合使用，不仅使结晶细致，整平性能提高，而且可以晶面产生强烈的择优取向，从而使镀层光亮如镜。     

更换镀银光亮剂所引起的故障及处理

１问题的提出我厂的氰化物镀银采用如下工艺：硝酸银５０ｇ／Ｌ氰化钾９０ｇ／Ｌ酒石酸钾钠３０ｇ／Ｌ碳酸钾３０ｇ／Ｌ（只在配槽时加过）ＳＯ（光亮剂）多年来，我厂一直采用此工艺，操作简单易维护，但工艺不很稳定，尤其是到了夏季，镀层易粗糙、表面结晶不细致、表面...     

NS光亮镀银工艺生产实践

ＮＳ光亮镀银工艺生产实践解长利（贵州六盘水煤矿机械厂，５５３４０２）１工艺流程化学除油→水洗→酸洗→水洗→上挂具→１：１盐酸酸洗→水洗→浸硫脲银→水洗→３％ＨＮＯ３→漂洗→水洗→蒸馏水洗→镀银→水洗→成膜→水洗→去膜→水洗→１０％ＨＣｌ酸洗→水洗→电...     

镀银过程中光亮剂的电极行为

通过阴极极化曲线，微分电容曲线以及ＸＲＤ，ＳＥＭ分析，研究了光亮剂在脉冲及直流电镀银过程中的作用。结果表明，光亮剂在直流与脉冲电镀时的电极行为基本一致，光亮剂Ａ具有去极化作用，并使微分电容增大，光亮剂Ｂ具有增加阴极极化，降低微分电容的作用。     

从镀银废金属中回收银的试验研究

本文提出利用浓硫酸与硝酸的混合酸选择性溶解金属银，稀释后析出Ａｇ２ＳＯ４，再与ＫＯＨ焙烧还原来回收含银废金属中银的新方法。     

氰化光亮镀银

一引言由于银具有良好的导电性,一定程度的可焊性以及抗蚀性,其在电器制造行业中得到了广泛的应用。以往镀银基本上都是采用传统的氰化非光亮镀银工艺。该工艺有下列不足: 1 外观较差,抗蚀能力较低。把非光亮镀层转化成光亮镀层,一般需在含铬酸的溶液中进行化学抛光,每次抛光约要去掉1.5μm厚的镀层。不仅要产生含铬污水污染,而且还要浪费不少银。此外,引入抛光需要增加去膜、浸亮、清洗等多道工序使工艺复杂。 2 镀层经过一定时间贮存后,由于硫化而使可焊性和一定的导电性能被恶化。     

装饰性光亮镀银

本文以咖啡壶装饰光亮镀银为例,介绍了餐具和工艺品装饰镀银的工艺过程及工艺要点:1.选择适于基体和表面状态的镀前处理;2.为保证镀层附着强度而进行的预镀铜;3.光亮镀镍添加剂的选择和镀液的维护;4.银的预镀和光亮镀银工艺的选择;5.装饰镀银的防变色处理.     

增强不锈钢镀银层结合力的电解活化法

不锈钢表面极易钝化，从而影响镀层的结合力，用混酸（ＨＮＯ＿３＋ＨＦ＋ＨＣｌ）在５０～６０℃处理不锈钢表面，银镀层的结合力仍不强。采用ＮｉＣｌ＿２＋ＨＣｌ电解液，镍极为对电极，将不锈钢进行阳极处理，再进行阴极处理，镀氰化铜，镀银，这样预处理取得了非常优良的效果，镀银层在常温、低温和高温都有很强的结合力。还对电解活化的化学机理进行了讨论。     

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.     

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.     

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.     

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.     

基于ATRP法制备的触角状亲水性羟胺树脂的吸硼性能的研究

以大分子引发剂氯乙酰化聚苯乙烯微球(PS-acyl-Cl)经原子转移自由基聚合(ATRP)法引发丙烯酰胺(AM)和甲基丙烯酸缩水甘油酯(GMA)单体的共聚接枝,制得一种触角状亲水性环氧载体(PS-acyl-g-P(AM-co-GMA)),再经二乙醇胺(DEA)的环氧基开环胺化反应,得到一种含多个-NCH2CH2OH螯合配基的多齿-五元螯合环的触角状亲水性羟胺树脂(PS-acyl-g-P(AM-co-GMA)-DEA)。将此树脂用于硼吸附研究,结果表明,PS-acyl-g-P(AM-co-GMA)-DEA树脂对硼的吸附满足Langmuir方程,为单分子层吸附;饱和吸附量约为37.7 mg·g-1,且树脂5 min即可达到吸附平衡,与其它已报道的吸硼树脂相比,该树脂具有更高的吸附量和吸硼速率。吸附动力学研究表明,树脂吸附硼的过程主要由颗粒扩散过程控制。重复使用5次后该树脂的吸附量基本不变,解吸率均在90%以上,重复使用性能良好。