配位剂对GH202合金化学镀镍–磷的影响

研究了配位剂CH3COONa和NH4Cl对GH202合金酸性化学镀镍镀速和镀层磷含量的影响,分析了化学镀过程中镍离子和次磷酸根离子的消耗量。镀液的组成和工艺条件为:NiSO4·7H2O 80 g/L,NaH2PO2·H2O 24 g/L,H3BO3 8 g/L,CH3COONa·H2O 6~15 g/L,NH4Cl 3~6 g/L,pH 5.0,温度85°C,时间2 h。随镀液中CH3COONa含量增加,沉积速率先增大后减小,镀层磷含量则在6.19%~10.45%范围内呈小幅波动。随镀液中NH4Cl含量增大,沉积速率变化不大,但镀层磷含量减小。随化学镀时间延长,镀液中镍离子和次磷酸根离子的消耗速率均减小。镀液中CH3COONa与NH4Cl的较优质量浓度分别为12 g/L和6 g/L。采用该体系化学镀所得Ni–P镀层表面平整,厚度约为50μm,磷的质量分数为6.19%,结合力良好,综合性能基本满足GH202合金表面预镀镍层的要求。     

pH对脉冲电镀锌–镍–锰合金的影响

在Q235钢表面脉冲电镀Zn–Ni–Mn合金,镀液组成和工艺条件为:ZnSO_4·7H_2O 43.1 g/L,MnSO_4·H2_O 59.2 g/L,NiSO_4·6H_2O26.3 g/L,Na_3C_6H_5O_7·2H_2O 176.5 g/L,NH_4Cl 30 g/L,H_3BO_3 30 g/L,十二烷基硫酸钠(SDS)0.1 g/L,p H 4.5~6.0,温度30°C,平均电流密度30 m A/cm~2,脉冲占空比20%,脉冲周期1 ms,时间20 min。研究了pH对合金镀层元素组成、沉积速率、表面形貌和耐蚀性的影响。结果表明,随p H增大,沉积速率减小;镀层中锰含量升高,锌、镍含量降低;耐蚀性先增强后减弱。p H为5.0时,所得Zn–Ni–Mn合金镀层平整致密,Zn、Ni和Mn的质量分数分别为85.71%、5.03%和9.26%,中性盐雾试验96 h的保护等级为5级。与Zn–Ni合金镀层(Ni质量分数为12.88%)相比,Zn–Ni–Mn合金镀层的腐蚀电位正移了85 mV,腐蚀电流密度低了约2个数量级,耐蚀性更优。     

电沉积方式对镍–铬–钼合金镀层性能的影响

分别采用直流(DC)、单脉冲(PC)和换向脉冲(PRC)方式在Q235钢表面制备Ni–Cr–Mo合金镀层。镀液组成为:NiSO_4·6H_2O 131.4 g/L,CrCl_3·6H_2O 13.3 g/L,Na_2MoO_4·2H_2O 12.1 g/L,柠檬酸铵145.9 g/L,尿素60 g/L,抗坏血酸8.8 g/L,H_3BO_3 14 g/L,NH_4Br 10 g/L,十二烷基硫酸钠0.1 g/L。对比了采用不同方式电沉积所得Ni–Cr–Mo合金镀层的外观、表面形貌、元素组成、沉积速率、表面粗糙度和耐蚀性。3种方式电沉积所得合金镀层的外观均良好。单脉冲和换向脉冲电沉积合金镀层的组成相近,直流电沉积合金镀层的镍、钼含量比它们高,但铬含量较低。换向脉冲电沉积合金镀层的微观表面最均匀、致密,粗糙度最低(0.587μm),耐蚀性最好。     

6063铝合金化学镀镍–磷合金镀层的性能

以6063铝合金为基体进行化学镀Ni–P合金镀层,镀液组成和工艺条件为:NiSO4·6H2O 25~28 g/L,NaH2PO2·H2O 20~25 g/L,NH4HF2 20~23 g/L,CH3COONa·3H2O 15~20 g/L,C6H8O7 8 g/L,KIO3 0.1 g/L,温度(80±2)°C,pH 5.5~6.0,时间2 h。表征了Ni–P镀层的形貌、结构、结合力、孔隙率以及耐蚀性等性能。结果表明,Ni–P镀层表面致密,呈非晶态,厚度为15μm,显微硬度为476 HV,结合力良好,耐蚀性明显优于基体。     

镍磷纳米化学复合镀中纳米二氧化钛的分散性研究

利用X射线光电子能谱仪(XPS)分析了不同纳米Ti O2含量的Ni–P化学镀液所制备的Ni–P–TiO 2复合镀层中纳米TiO 2的含量及其分布状况,在以乳酸为配位剂、聚乙烯吡咯烷酮(PVP)为表面活性剂的Ni–P–Ti O2化学复合镀液中,采用红外–可见–紫外分光光度法研究了不同用量的乳酸和PVP以及镀液p H对纳米Ti O2分散性的影响,获得了最佳的分散条件:纳米Ti O2加入量3.0~4.0 g/L,PVP 0.2 g/L,乳酸4.5 m L/L,p H 5.0~5.5。     

pH对化学复合镀镍–磷–聚四氟乙烯性能的影响

考察了pH对45钢上化学复合镀Ni–P–聚四氟乙烯(PTFE)沉积速率和镀层孔隙率、磷含量、表面形貌、耐蚀性、显微硬度和摩擦因数的影响。镀液组成和工艺条件为:NiSO_4·6H_2O 25 g/L,NaH_2PO_2·H_2O 30 g/L,无水乙酸钠20 g/L,柠檬酸20 g/L,硫脲2 mg/L,氟碳型表面活性剂18 mg/L,PTFE 1.0 g/L,温度85℃,时间1 h。pH为5.0时,沉积速率为15.93μm/h,所得为高磷(质量分数8.34%)复合镀层,其显微硬度为163.3 HV,摩擦因数0.25,能耐中性盐雾腐蚀24.5 h。     

铁-钨-磷合金电沉积工艺及其性能研究

在含FeSO4·7H2O、Na2WO4·2H2O、NaH2PO2·H2O、Na3C6H5O7·2H2O、C6H8O7·H2O、NH3·H2O和苯亚磺酸钠的碱性镀液中,电沉积得到Fe–W–P三元合金,分析了不同镀液成分时所得镀层的化学组成,讨论了温度、pH、电流密度及NH3·H2O用量对镀层沉积速率和显微硬度的影响。结果表明:除NaH2PO2·H2O外,镀液中其他组分对镀层组成均有显著影响;工艺参数的改变对镀层沉积速率和显微硬度有一定影响,NH3·H2O体积分数对沉积速率的影响尤其显著。电沉积所得Fe–W–P合金镀层具有典型的非晶态结构,其耐蚀性略优于00Cr17Ni14Mo2不锈钢。     

钢铁全光亮化学镀镍–钨–磷合金工艺研究

为了提高Ni–P合金镀层的耐蚀性和表观质量,在化学镀Ni–P二元合金镀液的基础上加入钨酸钠,在钢铁上制备了Ni–W–P三元合金镀层。探讨了镀液主要成分和工艺条件对镀层外观质量及耐蚀性的影响,获得了较佳的工艺规范:硫酸镍25~35 g/L,钨酸钠55~65 g/L,次磷酸钠30~40 g/L,复合配位剂80~100 g/L,组合光亮剂5~10 mg/L,p H 8.5~9.0,温度80~90°C。检测了镀层的相关性能。结果表明,所制备的Ni–W–P合金镀层结晶细致,光亮度和结合力好,具有良好的装饰效果,耐蚀性优于化学镀Ni–P合金镀层。     

镍铁–立方氮化硼复合电刷镀工艺研究

通过复合电刷镀在20钢基体表面制备镍铁–立方氮化硼(CBN)复合镀层。研究了施镀电压、镀液温度及镀笔速率对复合镀层中CBN含量的影响,分析了镀层中CBN含量与耐磨性之间的关系。复合电刷镀NiFe–CBN的镀液组成和最佳工艺条件为:NiSO4·6H2O 270~300 g/L,FeCl2·2H2O 23~27 g/L,H3BO326~30 g/L,Na3C6H5O7·2H2O 20~30 g/L,糖精2~3 g/L,十六烷基三甲基溴化铵0.2~0.3 g/L,pH 3.2~4.0,电压14 V,温度50°C,镀笔速率15 m/min,时间100~120 min。在最佳工艺下所得镀层的CBN质量分数为9.8%,显微硬度为770 HV,耐磨性和结合力良好。     

高碳化硅含量的镍–钨–微米碳化硅复合电镀及其耐蚀性

采用电沉积法在铁片上制备Ni–W–微米SiC复合镀层。研究了微米SiC颗粒用量、pH、电流密度等工艺参数对复合镀层中SiC颗粒含量的影响,得到最优工艺为:NiSO_4·6H_2O 20 g/L,Na_2WO_4·2H_2O 50 g/L,Na_3C_6H_8O_7·2H_2O 50 g/L,微米SiC颗粒20g/L,pH7.0,电流密度2.5 A/dm~2。采用X射线衍射仪、扫描电子显微镜、能谱仪和浸泡腐蚀试验表征了Ni–W–微米SiC复合镀层的晶相结构、表面形貌、元素组成和耐蚀性。采用红外光谱法初步探讨了SiC微米颗粒的沉积机理。结果表明,SiC微米颗粒在复合镀层中的质量分数可高达42.5%,SiC微米颗粒的存在能消除Ni–W合金镀层的裂纹,从而提高镀层对基体的保护能力。镀液中的阴离子可能对SiC微米颗粒的沉积过程有一定的影响。     

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。