化学镀Ni-P-Al2O3复合镀层的研究

研究了在Q 235钢表面制备Ni-P-Al2O3复合镀层的工艺条件,并表征了Ni-P-Al2O3复合镀层的组成、形貌、硬度及耐蚀性等性能。通过实验,确定最佳的工艺条件为:温度85℃,pH值4.6,Al2O330g/L。SEM和EDS研究表明:Al2O3微粒在镀液中会被活化,在进入复合镀层的过程中,其表面沉积有均匀的镍层。镀层性能测试结果表明:复合镀层的硬度和耐蚀性均明显优于Ni-P镀层的。     

硫代硫酸钠无氰镀银

研究了硫代硫酸钠无氰镀银工艺中各组分含量的变化对银镀层在附着力、光亮度等性能的影响,获得各自的最佳配比;通过改变阴极电流密度、pH值,考察对银镀层质量的影响,得到最佳的硫代硫酸钠无氰镀银工艺.     

憎水性Ni-PTFE复合镀层的制备及其摩擦磨损性能的研究

采用复合电镀法制备Ni-PTFE复合镀层,考察了表面活性剂、电流密度、pH值和镀液中PTFE添加量对复合镀层中PTFE含量的影响.并进一步研究了镀层中PTFE含量对复合镀层硬度、摩擦磨损性能和憎水性能的影响.结果表明,最佳工艺条件下制备的复合镀层具有良好的憎水性和优异的摩擦磨损性能.     

镁合金化学镀镍工艺

研究了采用碱式碳酸镍作为镍源在AZ91镁合金表面直接化学镀镍的工艺。该工艺采用酸洗活化一步法,即经过脱脂除油,再用H3PO4、NH4HF2以及缓蚀剂处理,无需活化。通过比较3种酸洗液的应用效果,确定60mL／LH3PO4,40g／LNH4HF2,30g／LH3BO3的混合液作为酸洗液。酸洗最佳pH约为2,时间为25s。实验发现,该法较HF活化得到的镀层表面颗粒更均匀。该Ni-P镀层结合力合格,硬度可达356．7HV。讨论了热处理温度对镀层硬度的影响,结果表明随热处理温度的提高,镀层硬度也随之提高,在热处理温度为250℃时,硬度达最大。通过Tafel曲线分析得出,AZ91镁合金采用该工艺进行化学镀镍后,耐蚀性有了很大改善。     

三价铬电镀硬铬工艺的中试研究

试验在200 L氯化物体系三价铬镀液中进行,镀件为Φ50 min×100 mm的钢管或铜管.在不同的温度和pH值下施镀来确定最佳工艺范围.利用称重法测量镀层的厚度,并计算镀速和电流效率.在200 mL镀液中进行加速试验,以研究镀液的分析调整方法,并测试镀液的寿命.通过维氏显微硬度仪测试镀层的硬度与热处理温度的关系,并在扫描电予显微镜下观察镀层的形貌.在SRV摩擦试验机上对比三价铬镀层和六价铬镀层的摩擦学性能.结果表明:与六价铬电镀工艺相比,三价铬电镀工艺具有低毒性、常温施镀、电流效率高、生产效率高、镀层性能好等优点,但其调整维护相对频繁、复杂.     

纳米碳纤维表面非晶态Ni-Fe-Ru-P合金镀层的制备与表征

在铁片试样上研究以次磷酸钠为还原剂的化学镀Ni-Fe-Ru-P合金镀层的工艺,考察了金属盐浓度对化学镀反应沉积速率的影响.利用优化的工艺配方在经过敏化,活化处理后的纳米碳纤维表面沉积Ni-Fe-_Ru-P合金镀层,分别利用EDS、XRD、SEM等手段对镀层的成分,结构,形貌进行了表征,并对其进行了热处理.结果表明,利用化学镀技术可以在纳米碳纤维表面获得连续、均匀的Ni-Fe-Ru-P合金镀层,且镀层为非晶态结构.在350℃以下热处理不会改变镀层的结构,在400℃以上热处理,镀层开始晶化.     

普通回收塑料表面化学镀镍工艺的研究

实验研究了回收塑料表面化学镀镍的工艺方法及操作条件,探索了不同的实验条件,包括温度、pH值,主盐浓度、络合剂配比等,对镀层质量的影响。确定了镀镍的最佳操作方法、工艺流程和控制条件。实验结果表明,经过除油、粗化、敏化及活化等预处理的回收塑料表面,镀镍温度为50℃,pH值为7.0,施镀时间为120 min时,可以得到比较好的金属镍镀层。     

(Ni-P)-WC纳米微粒复合电镀的研究

研究了WC纳米微粒质量浓度、阴极电流密度、pH值、温度、搅拌方式等工艺参数对(Ni-P)-WC纳米微粒复合镀层沉积速度的影响,并通过正交试验,确定了复合电镀的最佳工艺参数。对镀层的表面形貌、成分及不同热处理条件下的硬度进行了观察与测定,实验结果表明,镀层表面均匀,有质量分数为2．0％～3．5％的WC纳米微粒的镀层;热处理后硬度可达1240HV。     

纳米复合镀层的制备及性能研究

以铁片作为基材,采用电镀工艺制备Ni-ZrO2纳米复合镀层。研究了温度、pH值、时间及ZrO2的质量浓度对复合镀层性能的影响。通过实验得出最佳的工艺参数为:ZrO21.5g/L,pH值4～5,50℃,60min。采用扫描电子显微镜观察复合镀层的微观形貌,并通过XRD分析其相组织成分。结果表明:复合镀层表面光亮,微粒均匀、细小;其相组织成分主要为Ni,ZrO2和Ni-ZrO2。     

化学复合镀Ni-P—PTFE的镀速及镀层摩擦学性能研究

在45#钢上化学镀Ni-P-PTFE复合镀层,其工艺流程主要包括化学机械抛光、碱性除油、活化、化学镀和干燥,研究了主盐和还原剂质量浓度、pH、温度以及PTFE体积分数对镀速的影响.观察了Ni-P-PTFE镀层的表面形貌,测试了镀层的摩擦性能.结果表明:当工艺条件为25 g/L硫酸镍、30 g/L次磷酸钠、10 mL/L PTFE.pH 4.6和温度(92±2)℃时,镀速最佳,镀层的摩擦因数在0.16～0.20之间,具有优良的耐磨性能.     

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.     

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.     

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。