不锈钢热浸镀—扩散铝在三元混合碳酸盐中腐蚀行为研究

为进一步提高马氏体不锈钢1Cr13的耐熔融盐腐蚀性能,对该钢进行了热浸镀铝后高温热扩散处理和在三元混合碳酸盐中的抗高温腐蚀的试验。试验结果表明:经过热浸镀铝和热扩散铝处理,1Cr13不锈钢在三元混合碳酸盐中的耐腐蚀性能有一定提高,形成的Fe-Al合金层能明显减少高温Li-Na-K碳酸混合盐材料表面氧化膜的厚度并且减缓了腐蚀。     

四元溴化盐对碳钢的高温腐蚀实验研究

熔盐是一种高效传热蓄热工质,其在熔盐传热蓄热系统中对熔盐泵、阀门、各种传感器、管道等金属材料设备的腐蚀特性是熔盐应用的限制因素之一,因此确定熔盐对金属材料的腐蚀性能至关重要。为研究四元溴化盐对碳钢(Q235)的高温腐蚀性能,以浸没法在450℃温度下进行碳钢样片的静态腐蚀实验,得到样片在溴化盐腐蚀环境中的腐蚀动力曲线,并对样片腐蚀区域进行扫描电镜和X射线物相分析。实验结果表明,在高温溴化盐腐蚀环境中,碳钢样片被腐蚀的质量损失量随时间延长而增加,腐蚀360h后样片质量损失达到24.14mg/cm²;样片表面产生了电化学腐蚀,腐蚀产物以铁、锰的氧化物为主。     

蓝晶石在炭砖中的原位分解及其对性能的影响

本文在炭砖中添加蓝晶石细粉,讨论了蓝晶石在炭砖中的反应过程及其对炭砖物相变化、显微结构与宏观性能的影响.结果表明,在高导热炭砖试样中添加蓝晶石,焙烧温度达到1300℃以上时发生莫来石化反应,其反应产物二氧化硅可与含碳组分发生碳化反应,有利于增加碳化硅晶须的生成量,改善试样微孔性能.     

磷酸槽内衬防腐炭砖膨胀性能的研究

化工大型磷酸反应槽中炭砖内衬层的防腐蚀作用非常重要.本文对炭砖在温度小于95℃的环境下的热膨胀、泡水膨胀规律进行了研究.其结论对反应槽设计、炭砖综合性能评价均有参考价值.     

磷炉炭砖的腐蚀原因分析

分析了磷炉炭砖的腐蚀原因,认为炉壁厚度、炭砖的外形尺寸的大小及形状、填料的特性和性能变化以及炭砖砌体的性质、磷炉使用时炭砖的热膨胀、机械应力和热应力都是影响炭砖腐蚀程度的重要因素。     

介孔炭的改性及其吸附脱硫选择性研究

用4种方法(浓硝酸、磷酸、双氧水、350℃焙烧)对介孔炭进行改性,并考察改性后的介孔炭在4种不同成分的模拟油中的吸附脱硫性能。对于仅含有芳烃或烯烃以及芳烃和烯烃均含有的模拟油,改性介孔炭的脱硫能力与未改性的介孔炭相比均有不同程度的下降。浓硝酸改性的介孔炭在仅含饱和烃的模拟油中的吸附脱硫性能优于其它方法;350℃焙烧处理的介孔炭与未改性的介孔炭在芳烃和烯烃均含有的模拟油中的吸附脱硫性能优于其它方法。考察了在350℃焙烧及浓硝酸处理后的介孔炭在不同温度下的脱附性能。结果表明,350℃焙烧处理的介孔炭在90℃下脱附率能达到66.91%。     

介孔炭的改性及其吸附脱硫选择性研究

用4种方法(浓硝酸、磷酸、双氧水、350℃焙烧)对介孔炭进行改性,并考察改性后的介孔炭在4种不同成分的模拟油中的吸附脱硫性能。对于仅含有芳烃或烯烃以及芳烃和烯烃均含有的模拟油,改性介孔炭的脱硫能力与未改性的介孔炭相比均有不同程度的下降。浓硝酸改性的介孔炭在仅含饱和烃的模拟油中的吸附脱硫性能优于其它方法;350℃焙烧处理的介孔炭与未改性的介孔炭在芳烃和烯烃均含有的模拟油中的吸附脱硫性能优于其它方法。考察了在350℃焙烧及浓硝酸处理后的介孔炭在不同温度下的脱附性能。结果表明,350℃焙烧处理的介孔炭在90℃下脱附率能达到66.91%。     

添加碳化硅对电煅煤基高炉炭砖显微结构和性能的影响

采用不同粒度碳化硅部分取代高炉炭砖中的电煅煤骨料,借助X射线衍射仪、场发射扫描电镜、能谱仪以及激光导热仪等研究了碳化硅的引入对高温焙烧后高炉炭砖物相组成、显微结构和导热系数等性能的影响,并使用支持向量机回归建模算法建立了炭砖导热系数的数学模型,分析了各因素对炭砖导热系数影响程度.结果表明:碳化硅的加入可促进炭砖基体内原位陶瓷相AlN和β-SiC晶须的生成,进而有助于提高炭砖的耐压强度、导热系数和抗铁水侵蚀性能;由支持向量机建模分析得知,大粒度碳化硅的加入量和焙烧温度对导热系数提高的影响较为明显,适当增大大粒度碳化硅的含量并提高焙烧温度有可能进一步提高炭砖的导热系数.     

1Cr13不锈钢三元混合碳酸盐中的腐蚀研究

通过分析1Cr13不锈钢在750℃Li-Na-K三种混合碳酸熔融盐中的腐蚀动力学曲线和热腐蚀后的形貌和物相组成,讨论了1Cr13不锈钢在这三种熔盐中的腐蚀机理,并进行了对比,分析了不同组成的Li-Na-K碳酸盐熔盐体系对不锈钢腐蚀的影响。结果表明:Li2CO3能够减缓腐蚀,阻止腐蚀的进一步进行,具有保护性,减缓表面裂纹出现的可能性;而K2CO3能够增大氧化膜的溶解性,具有一定的破坏性。     

还原气氛对高铬砖性能的影响

为了有效提高高铬砖的常温物理性能和抗侵蚀性能,延长其在水煤浆加压气化炉中的使用寿命,在埋炭条件下,分别于1350、1450和1550℃烧成高铬砖,并与1700℃空气中烧成试样对比,研究了烧成气氛(埋炭和空气气氛)对高铬砖体积密度、显气孔率、常温耐压强度和抗熔渣渗透性能的影响。结果表明:随着温度升高,高铬砖的显气孔率下降、体积密度增加,而1450℃埋炭烧成高铬砖的常温耐压强度最高,达到214MPa;埋炭能显著降低高铬砖的烧成温度和改善其显微结构;1450℃埋炭烧成高铬砖的抗熔渣渗透能力优于1700℃空气中烧成试样的。     

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。