镀液组成对刷镀(Ni-P)-SiO2工艺的影响

研究了(Ni-P)-SiO2刷镀液中Ni2 离子、NaH2PO2、SiO2微粒、金属盐的比例、温度等因素对刷镀(Ni-P)-SiO2工艺的影响.结果表明,在刷镀(Ni-P)-SiO2工艺中,选择适当刷镀液组成,刷镀层沉积速率和镀层质量明显提高,并由此得出了刷镀(Ni-P)-SiO2合金工艺的最佳镀液组成.     

(Ni-P)-纳米Si3N4微粒复合刷镀工艺研究

论述了（Ni-P)-纳米Si3N4微粒复合刷镀工艺,设备及（Ni-P)-纳米Si3N4微粒复合刷镀液的组成和配制方法;研究了纳米Si3N4微粒在刷镀液中的含量,刷镀工作电压和刷镀温度对（Ni-P)-纳米Si3N4微粒复合刷镀层的影响;研究了在不同的热处理温度下复合刷镀层的硬度和耐磨性。     

(Ni-P)-纳米Si3N4复合刷镀层结构及性能研究

1引言 复合刷镀是指在镀液中纳米级的不溶性的固体形成纳米复合刷镀层.用具有很好悬浮性能的纳米Si3N4固体微粒作为复合刷镀液的第二相粒子,通过搅拌使其悬浮在镀液中,用电刷镀的方法使Ni-P合金与纳米Si3N4微粒共沉积于基体表面.它具有沉积速度快、镀层硬度高和耐磨性好等优异的性能.     

聚乙烯亚胺对Si3N4纳米微粒复合刷镀的影响

研究了聚乙烯亚胺对刷镀(Ni-P)-Si3N4纳米微粒复合镀液中Si3N4纳米微粒的分散性、刷镀层性能及结构的影响,并确定了聚乙烯亚胺在复合刷镀液中的最佳含量。结果表明,聚乙烯亚胺能有效阻止复合刷镀液中颗粒的絮凝、团聚,其用量对复合刷镀层中Si3N4含量、刷镀层硬度及耐磨性能有显著的影响。当其质量浓度为0.8 g/L时,获得了微粒均匀分散,稳定悬浮的复合刷镀液,复合刷镀层微观表面结构致密,微粒分布均匀,磨损量最小,显微硬度最大。     

( Ni-P)-Al2O3纳米微粒复合镀层硬度和耐磨性测试

为了改进钢材表面性能,采用复合化学镀技术制备( Ni-P) -Al2O3纳米微粒复合镀层,由于纳米微粒独特的物理化学特性致使使得到的复合镀层具有多种优良性能.通过Ni-P合金镀层、(Ni-P) -Al2O3纳米微粒复合镀层和热处理后的(Ni-P) -Al2O3纳米微粒复合镀层硬度和耐磨性能测试,得出(Ni-P)-Al2...     

复合电镀(Ni-P)石-墨工艺及镀层性能的研究

用复合电镀方法在低碳钢基体上镀覆(Ni-P)-石墨复合镀层.研究了表面活性剂、石墨微粒的悬浮量及阴极电流密度对镀层中石墨微粒含量的影响.结果表明,当镀液中石墨微粒约为12g/L、搅拌速度120 r/min、温度为45℃、pH为4,镀层中石墨微粒含量最高.对镀层的表面形貌、耐蚀性、硬度、减摩性及耐磨性进行了测定,与Ni-P合金镀层相比,(Ni-P)-石墨复合镀层有良好的综合性能.     

化学镀(Ni-P)-WC纳米微粒复合镀层的研究

采用化学镀的方法制备(Ni-P)-WC纳米微粒复合镀层,研究了镀液中WC纳米微粒的添加量对镀层中微粒含量的影响,通过扫描电镜观察了(Ni-P)-WC纳米微粒复合镀层的表面形貌。研究发现,纳米微粒镀层的硬度随着镀层中WC纳米微粒含量的增加而提高。通过测量(Ni-P)-WC纳米微粒复合镀层在NaCl溶液中的开路电位曲线和电化学阻抗谱,发现其耐蚀性能要优于合金镀层。     

铝合金表面Ni-P复合刷镀层的制备与性能

论述了铝合金表面刷镀Ni-P合金的工艺条件，研究了铝合金表面刷镀Ni-P合金的性能，热处理温度对铝合金表面Ni-P合金刷镀层硬度和耐磨性有较大的影响，经400℃热处理后，硬度和耐磨性达到最大值，在铝合金零部件上刷镀Ni-P合金具有刷镀层硬度高，耐磨性好，解决了铝及铝合金表面硬度低，易磨损等问题，具有广泛的应用前景。     

化学沉积新型复合材料的研究

近年来,复合化学镀技术在开发新材料的探索中已为人们所关注。本文在酸性化学镀Ni-P合金的溶液中,加入T-稳定剂,以TiN微粒为分散剂,成功地制备出一种新型的(Ni-P)-TiN复合镀层。实验结果表明,TiN微粒在镀层中的含量与镀液中的悬浮量的关系呈Langmuir等温吸附线的形式。当维持TiN在镀液中的悬浮量不变,镀层中的TiN含量还与镀液的pH值及温度有关。经试验测定,(Ni-P)-TiN复合镀层的硬度随微粒含量的增加而增加,与化学镀Ni-P合金相比,具有更高的硬度值。经400℃热处理后,该复合镀层的硬度比硬铬镀层的硬度高。镀层耐磨性试验结果表明,(Ni-P)-TiN复合镀层比化学镀Ni-P合金镀层及硬铬镀层具有更好的耐磨损性能,极适于在高温条件下工作,这种耐高温磨损的性能,可以弥补硬铬镀层之不足。此外,本文对(Ni-P)-TiN复合镀层的耐磨性机理进行了初步的探讨。     

(Ni-P)-PTFE化学复合镀工艺的研究

研究了(Ni-P)-PTFE化学复合镀工艺,讨论了镀液中表面活性剂、PTFE微粒、温度以及pH值等参数对镀层中PTFE微粒沉积量的影响规律,在此基础上,对(Ni-P)-PTFE化学复合镀工艺参数进行优化,获得了最佳的工艺参数.     

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。