原板的电化学酸洗对镀锡板表面形貌及孔隙率的影响

研究了电化学酸洗对镀锡板孔隙率的影响。采用X射线荧光光谱仪(XRF)、扫描电子显微镜(SEM)、金相显微镜、原子力显微镜(AFM)等对原板表面成分、形貌以及锡的电沉积层形貌进行了表征,并测试了镀锡板的孔隙率。结果表明:随着酸洗时间的延长,原板表面富集的锰元素含量减少,铁晶粒暴露程度增大,电沉积的锡晶粒逐渐细化,镀锡板孔隙率降低。     

脉冲电沉积纳米晶Zn涂层的结构表征与摩擦学性能

采用脉冲电沉积法,通过调节电流密度控制涂层的晶粒尺寸,在铜基体上制备了平均晶粒尺寸为6~32 nm的Zn涂层,采用XRD, SEM和显微硬度、摩擦实验等手段,表征了涂层的微观结构,并研究了其力学性能与摩擦学性能. 结果表明,纳米晶Zn涂层的表面平整致密,平均晶粒尺寸随电流密度增大而减小,随着晶粒尺寸减小,涂层的显微硬度增大,摩擦系数降低. 当电流密度从0.3 A/cm2增大至2.4 A/cm2时,平均晶粒尺寸从32 nm下降为6 nm,显微硬度从低于0.5 GPa增大至2.0 GPa以上,在大气环境中与Si3N4球之间的滑动摩擦系数从0.18降低至0.05. 硬度随晶粒尺寸的变化规律符合经典的Hall-Petch关系.     

碳氧化硅的制备及表征

在惰性气体保护下,将硫化的有机硅纳米颗粒在600～1300℃进行高温热解.可制成碳氧化硅;并随着制备方法的不同,分别得到粒径为10～60 nm的碳氧化硅纳米颗粒、或粒径为～100 μm的多孔性碳氧化硅颗粒,以及负载在硅基板上的纳米尺寸的碳氧化硅膜.对产物进行了TEM、SEM、XPS、XRD和AFM等表征.     

脉冲电沉积纳米晶镍镀层的织构与硬度

采用脉冲电沉积方法在304不锈钢表面制备出具有不同织构的纳米晶镍镀层。采用X射线衍射仪对镀镍层的结构进行了表征,并用超显微微米压痕仪测量了镀镍层的硬度。结果表明:随着电镀时间的延长,镀镍层的晶粒尺寸变化不大,约为(14±2)nm;择优晶面由(111)向(200)转变;硬度由6070 MPa降至3 750 MPa。织构的变化显著影响镀镍层的硬度,随着织构系数TC(111)的降低,镀镍层的硬度逐渐下降。     

氟化SiO2纳米颗粒双疏涂层的制备及性能研究

采用氟化硅烷偶联剂对合成的单分散SiO2纳米颗粒进行表面接枝改性,并通过旋涂法将制备的氟化SiO2颗粒沉积在硅晶基板上.采用粒径分析仪、傅里叶变换红外光谱仪(FTIR)、热重分析仪(TG-DTA)、扫描电镜(SEM)和接触角测量仪对氟化SiO2纳米颗粒涂层的表面形貌、化学组成、接枝密度和润湿性能进行分析表征.结果表明:氟化硅烷偶联剂在SiO2纳米颗粒表面的接枝密度为5.94 nm-2;制备的氟化SiO2纳米颗粒薄膜具备微纳米双重复合网络结构,增加了涂层表面的粗糙程度;氟化SiO2纳米颗粒涂层展现出超疏水和强疏油性能,水和柴油在氟化SiO2纳米颗粒薄膜上的接触角分别为158.4°和125.7°.     

镧掺杂二氧化钛纳米球涂层的制备与亲水性表征

采用基于溶胶-凝胶和旋节分相相结合的方法在硅基板表面制备La3+掺杂二氧化钛纳米球涂层。通过扫描电子显微镜、X射线光电子能谱仪测试样品的表面形貌以及元素组成,并利用接触角测量仪测试样品的静态接触角。结果表明:在硅基板表面形成一层大小基本一致,分布均匀的、致密La3+掺杂纳米球状二氧化钛,其中掺杂离子是以置换的方式存在于二氧化钛晶格中。基板表面的纳米点中含有的元素包括La,Ti,O。与处理后的纯硅基板和纯二氧化钛纳米点阵相比,掺入La3+后,样品表面的润湿性能增强。     

液相反应自组装制备ZrO_2薄膜及性能研究

本次试验利用自组装单分子层技术与液相沉积技术的结合在较低温度下硅基板表面上沉积了二氧化锆晶态薄膜。并利用X-射线衍射仪、金相显微镜、扫描电镜等对二氧化锆膜层的相组成和表面形貌进行了观察。实验在前驱液是硫酸锆盐酸水溶液且硫酸锆的浓度为0.02 mol/L,盐酸溶剂的浓度为0.3 mol/L,沉积温度为70℃,沉积时间在10h以上且不会超过14h,烧结温度为500℃,并利用基底表面的功能化自组装膜层对前驱体溶液的诱导作用,在单晶硅基板表面制备出与基底结合紧密、结构致密均一的二氧化锆纳米晶态薄膜。     

铜基板法制备纳米碳纤维薄膜的研究

以乙炔(C2H2)作为碳源,采用化学气相沉积法(CVD)在经过草酸溶液腐蚀的铜基板表面制备出纳米碳纤维薄膜。采用扫描电子显微镜(SEM)和X射线粉末衍射仪(XRD)对产物进行结构与形貌表征,并对碳纤维薄膜进行其在基板上的附着性测试。结果表明,草酸腐蚀时间、化学气相沉积反应时间的变化等因素对纳米碳纤维薄膜的生长与形貌有一定影响。在反应温度为350℃时,铜基板表面制备出了一层均匀的纳米碳纤维薄膜,纤维直径为300~400 nm,薄膜的厚度为20~30μm。制备的纳米碳纤维薄膜对基板有良好的附着性。     

工艺因素对水热电泳沉积硅酸钇涂层显微结构的影响

采用水热电泳沉积法在C/C-SiC复合材料表面制备了硅酸钇抗氧化外涂层.研究了沉积电流密度和低温热处理对硅酸钇涂层的影响.采用X-射线衍射仪(XRD)和扫描电子显微镜(SEM)对涂层的相组成和显微结构进行了表征.结果表明:采用声化学法制备的硅酸钇微晶颗粒尺寸为25～40nm.随着沉积电流密度增加,硅酸钇涂层均匀性、致密性先逐渐增加后降低.当电流密度超过0.04 A/cm2时会导致涂层表面开裂.进行低温热处理,涂层表面硅酸钇纳米晶出现熔融现象;随热处理温度增加,涂层表面呈现玻璃化趋势.当热处理温度达1200℃时,表面完全熔融,形成致密的硅酸钇玻璃层.涂层在1500℃静态空气中,经过氧化10 h后,失重仍然小于2%.     

在钛基上电泳沉积羟基磷灰石生物陶瓷涂层的研究

将羟基磷灰石(HAP)电泳沉积在钛基材上，得到了结构稳定的HAP生物陶瓷涂层。研究了电场强度、悬浮液温度、电泳时间、分散介质及HAP浓度对涂层形貌的影响。通过红外光谱仪(FTIR)和X射线衍射仪(XRD)对涂层的组成及结构进行了分析，并采用扫描电镜(SEM)对涂层煅烧前后的微观形貌进行了观察。结果表明：在正丁醇作为分散剂、悬浮液温度30℃、电场强度250V／cm、电泳时间300s以及HAP浓度5．0g／L的条件下可制得形貌较好的HAP生物陶瓷涂层；经二次电泳沉积及煅烧后得到的HAP生物陶瓷涂层均匀致密．     

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。