脉冲电沉积铜-锡-镍-聚四氟乙烯复合镀层的组织结构和摩擦学性能

采用脉冲电沉积法在碳素工具钢表面制备Cu-Sn-Ni-PTFE复合镀层。镀液配方和工艺为:K_4P_2O_7·3H_2O 266.5 g/L,Cu_2P_2O_7·4H2O 20 g/L,NiSO_4·4H_2O 0.06~0.14 mol/L,KNaC_4H_4O_6·4H_2O 31.6 g/L,Na_2SnO_3·3H_2O 40 g/L,KNO_3 40 g/L,Na_3C_6H_5O_7·2H_2O 20 g/L,PTFE 10 g/L,pH 9.5~10.0,温度35~40℃,电流密度2.5 A/dm~2,脉冲频率3 000 Hz,占空比60%,转速100 r/min,时间1 h。研究了镀液中Ni~(2+)浓度对复合镀层表面形貌、组成、显微硬度及摩擦磨损性能的影响。结果表明,镀液中Ni~(2+)浓度为0.1 mol/L时,Cu-Sn-Ni-PTFE镀层表面均匀、致密,显微硬度高达391 HV,耐磨性最好。     

无氰电镀白铜锡工艺与镀层性能

通过赫尔槽试验与方槽试验研究了镀液组成和工艺条件对白铜锡电镀层外观与组成的影响。最佳镀液组成与工艺条件为:Cu2P2O7·3H2O16～19g/L,Sn2P2O712～15g/L,K4P2O7·3H2O200～250g/L,K2HPO460～80g/L,有机胺类添加剂JZ-11.2～1.8mL/L,pH=8.5～8.7,温度20～25°C,阴极电流密度1.0A/dm2。采用该工艺对基体施镀20min可得到厚度为5.09μm、锡的质量分数为40%～50%的均匀白亮的Cu-Sn合金镀层。Cu-Sn合金镀层的晶体结构以CuSn和Cu41Sn11为主,结晶细致、无微裂纹,显微硬度为372HV,耐蚀性能比相同厚度的光亮镍镀层好。     

无氰铜锡合金仿金电镀添加剂的研究

通过赫尔槽试验和方槽试验研究了添加剂H-3、DDS和JZ-1对焦磷酸盐溶液体系电镀仿金铜锡合金性能的影响。基础镀液组成为:K4P2O7·3H2O 240 g/L,Sn2P2O7 2.0 g/L,Cu2P2O7·3H2O 24 g/L,p H 8.7。结果表明,采用焦磷酸盐溶液体系电镀铜锡合金时,只有用到添加剂方可得到仿金镀层。添加剂H-3具有一定的整平、细化晶粒和提高光亮度的作用。H-3的用量为2.8 m L/L时,在黄铜基体上获得仿金镀层的阴极电流密度范围为0.29~2.25 A/cm2。焦磷酸盐溶液体系使用添加剂H-3时,在光亮酸铜、光亮镍、无氰白铜锡中间层上和直接在钢铁基体上进行仿金电镀时,均可获得光亮的仿金镀层。     

低锡铜-锡合金无氰电镀工艺

通过赫尔槽试验研究了镀液组成、pH和温度对低锡铜-锡合金镀层外观的影响,并用方槽电镀试验研究了时间和电流密度对低锡铜-锡合金镀层的厚度与组成的影响,得到最佳镀液配方与工艺条件为:Cu2P2O7·3H2O 25 g/L,Sn2P2O7 1.0 g/L,K4P2O7·3H2O 250 g/L,K2HPO4·3H2O 60 ...     

氮化铝陶瓷表面化学镀铜溶液组成的优化

采用正交试验方法研究了镀液组成对氮化铝(AIN)陶瓷表面化学镀铜镀速和表面粗糙度的影响.经过直观分析和方差分析,评价了各组分对化学镀影响的显著程度,优化了镀液组成.试验结果表明,CuSO_4·5H_2O和Na_2EDTA对镀速有显著影响;KNaC_4H_4O_6、CuSO_4·5H_2O和Na2EDTA对镀后表面粗糙度有显著影响;AIN陶瓷表面化学镀铜液的最优工艺参数为:CuSO_4·5H_2O 24 g/L,Na_2EDTA 30 g/L,KNaC_4H_4O_6 20 g/L和HCHO 15 mol/L.在最优工艺条件下,镀速为7.350 μm/h,镀后表面粗糙度为1.03 μm,所得镀层表面平整,铜晶粒大小均匀.     

添加剂对无氰电镀白铜锡工艺的影响

研究了多种胺类高分子添加剂对焦磷酸盐体系无氰电镀白铜锡工艺及镀层微观形貌的影响。基础镀液的组成为:K4P2O7·3H2O200～250g/L,Cu2P2O7·3H2O16～19g/L,Sn2P2O712～15g/L,pH8.5～8.7。以IEP(水性阳离子季铵盐)、DPTHE(多胺高分子聚合物)和JZ-1(胺类化合物)作添加剂时,均可在较宽的电流密度范围内得到白亮铜锡合金镀层。以IEP作添加剂时,电镀白铜锡的电流密度上限最高为3.70A/dm2;以DPTHE作添加剂时,电镀白铜锡合金镀层的电流密度下限最低为0.09A/dm2,可抑制低电流密度区形成金黄色低锡铜锡合金。以IEP和DPTHE作添加剂时,均可使白铜锡合金镀层持续增厚,电镀50min可得到白亮、无裂纹的镀层,且IEP具有更明显的整平和细化晶粒作用。     

添加剂对无氰电镀铜-锡合金(低锡)镀层性能的影响

通过赫尔槽试验与直流电解试验,研究了添加剂在焦磷酸盐溶液体系无氰电镀铜-锡合金(低锡)工艺中的作用。该体系镀液组成与工艺条件为:Cu2P2O7·3H2O25g/L,Sn2P2O71.0g/L,K4P2O7·3H2O250g/L,K2HPO4·3H2O60g/L,温度25℃,pH8.5,电流密度1.0A/dm2。采用扫描电镜(SEM)、X射线衍射(XRD)、能谱(EDS)、中性盐雾试验等方法研究了添加剂对镀层组成结构、外观、耐腐蚀性能及微观形貌的影响。结果表明,焦磷酸盐溶液体系无氰电镀铜-锡合金(低锡)时使用有机胺类添加剂可抑制Sn的析出,使合金镀层致密均匀,耐蚀性能好。镀层结晶主要为Cu13.7Sn结构,镀层中Sn含量为9%～11%。镀液中添加剂的使用量增加,则合金镀层中的Sn含量降低。     

焦磷酸盐溶液体系电镀白铜锡工艺

研究了溶液组成、pH、温度、阴极电流密度、施镀时间等对白铜锡合金镀层外观、厚度及成分的影响.较优的镀液组成及工艺条件为:Cu2P2O7·3H2O 30g/L,Sn2P2O74g/L,K4P2O7·3H2O200～250 g/L,K2HPO4 80g/L,pH 8.8,温度28～30℃,阴极电流密度0.6～1.0A/dm...     

镍?钴?纳米氧化铝复合电刷镀层在NaCl溶液中的腐蚀行为

采用电刷镀技术在45钢上制备了Ni-Co-纳米Al_2O_3复合镀层,镀液组成和工艺条件为:NiSO_4·7H_2O 100～125 g/L,CoSO_4·7H_2O 50g/L,NiCl_2·6H_2O 40g/L,HCOOH 18g/L,CH_3COOH 48g/L,盐酸150g/L,硫酸肼0.1g/L,纳米Al_2O_3 20g/L,正接,电压10～12V,镀笔速率5～8m/min,时间30min。通过塔菲尔曲线测试、电化学阻抗谱分析和浸泡腐蚀试验对比了电刷镀Ni-Co合金镀层、Ni-Co-纳米Al_2O_3复合镀层和挂镀硬铬层在5%NaCl溶液中的耐蚀性。结果表明,Ni-Co-纳米Al_2O_3复合镀层表面平整、均匀、致密,纳米Al_2O_3均匀分布,耐蚀性优于Ni-Co合金镀层和硬铬镀层,有望取代硬铬镀层在中性腐蚀环境中的应用。     

电刷镀制备镍/钴多层膜的工艺优化

采用单液法电刷镀制备200μm厚的Ni/Co多层膜镀层。镀液配方和工艺为:NiSO_4·7H_2O 250 g/L,CoSO_4·7H_2O 17~50 g/L,H_3BO_3 35 g/L,NaCl 20 g/L,十二烷基硫酸钠0.1~0.5 g/L,pH 2.0~5.0,温度40~60℃。通过单因素试验确定镀液的CoSO_4·7H_2O与NiSO_4·7H_2O的质量浓度比为1∶10,镍、钴单层的沉积电压分别为9.0 V和3.5 V。通过对比不同厚度单层膜的Ni/Co多层膜镀层的表面形貌、元素组成、表面粗糙度、显微硬度和耐磨性能,分析单层膜厚度变化对Ni/Co多层膜镀层性能的影响,最终确定较优单层膜厚度为4μm。所得Ni/Co多层膜镀层的显微硬度为496.8 HV,摩擦因数为0.42,耐磨性最好。     

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。