油基温拌剂对SBS改性沥青老化动力学参数的影响研究

对掺入LKWO-Ι型油基温拌剂前后的SBS改性沥青的软化点进行测试,并建立起一级反应老化动力学模型。求得掺入温拌剂前后的SBS改性沥青的老化动力学参数。结果表明,LKWO-Ι型油基温拌剂对SBS沥青老化过程反应活化能略有升高,在高温区对反应速率有一定的减缓作用,掺入温拌剂的沥青软化点明显降低。     

两种沥青抗老化性能研究

利用建立老化动力学模型来分析和研究再生沥青的抗老化性能。结合鞍山路面维修工程,选取有代表性的旧料,通过苯抽提出废旧沥青,分析技术指标,通过再生剂再生,再考察再生沥青在不同温度,不同老化时间的老化情况,并对老化后软化点进行研究。以老化后软化点为参数建立老化动力学模型。以软化点的变化为参数可以较好地表征再生沥青的动力学过程,求得正确动力学参数。鞍山再生沥青属于一级动力学反应。与辽河AH-90#沥青[1]横向对比,证明再生沥青抗老化性能[2]的可靠性。     

橡胶沥青温拌剂的开发与研究

制备了新型橡胶沥青温拌剂S,并从粘度、软化点、针入度、延度等方面研究了其用量对橡胶沥青性能的影响。采用4种试验,对比了温拌剂S与国外温拌剂的温拌性能,探讨了温拌剂S的降粘机理。结果表明,温拌剂S能显著降低橡胶沥青的高温粘度,提高橡胶沥青的软化点及针入度,还可提高橡胶沥青的抗老化能力、高温稳定性、低温抗裂性以及水稳定性。     

改性废轮胎橡胶粉对温拌沥青特性影响的研究

采用高速剪切法制备废橡胶粉改性温拌沥青,并对添加温拌剂E26和DWMA胶粉的改性沥青进行短期模拟老化试验。研究结果表明,加入温拌剂E26和DWMA改变了沥青四组分的含量,沥青内部结构未发生明显变化;短期老化后,针入度和延度减小,软化点升高;芳香分质量分数降低,胶质和沥青质质量分数增多。对比发现,添加DWMA温拌剂的胶粉改性沥青,老化前后三大指标和四组分变化幅度最小,官能团减小幅度最小,说明抗老化能力优于添加E26和未添加温拌剂的改性沥青。     

老化沥青软化点与沥青质关系的理论研究

根据沥青老化动力学的相关研究结果,通过推导,首次得到软化点与沥青质含量之间的定量关系式:(1-w)ts=C,为沥青老化动力学提供了理论基础.实验证实,该式可靠性良好.研究发现,老化后沥青软化点升高,是由于其类属组成和分子间作用力发生变化;由沥青四组分分析可知,沥青质是影响软化点最为重要的因素.基于软化点定义了沥青抗老化参数,它与正戊烷沥青质含量之间存在简单的线性关系,可以简洁有效的表征沥青的抗老化性能.     

再生SBS改性沥青老化性能的研究

以再生后的SBS改性沥青为原料,通过薄膜烘箱实验,考察了再生SBS改性沥青的软化点、针入度、延度、表观粘度与老化时间和老化温度的关系;建立了以软化点为参数的老化动力学方程,研究再生SBS改性沥青的抗老化性能。实验结果表明,再生SBS改性沥青在不同老化时间段内,各理化性能变化规律不同,其老化速率也不同;建立的再生SBS改性沥青老化动力学方程能够很好的反应再生沥青的老化过程。     

两种道路沥青老化动力学研究的比较

为了更加直观地了解废旧橡胶粉改性沥青的老化过程,通过旋转薄膜烘箱试验,比较了基质沥青和改性沥青的老化温度和软化点随着老化时间的变化情况。同时以软化点为参数建立老化动力学模型来反映两种沥青的老化情况,并计算出活化能。试验结果表明胶粉改性沥青的活化能高于基质沥青,表明其抗老化性能得到提高。并对沥青的老化机理进行了探讨。     

表面活性型温拌剂对沥青理化性质的影响

采用基于表面活性技术的LKW-Ⅱ型温拌剂,通过实验测得不同温拌剂加入量下温拌沥青的黏度,选取降黏效果最好的温拌剂加入量为3%。对温拌沥青针入度、软化点和延度理化性质的测定,实验结果显示,虽然LKW-Ⅱ型温拌剂对于沥青的延度没有太大影响,但其针入度增加,而软化点降低。     

Leadcap温拌剂对SBS改性沥青性能影响的研究

将不同掺量的Leadcap温拌剂按照一定的试验方法掺加进SBS改性沥青中,检测沥青的针入度、软化点、延度、布氏黏度和流变性能等指标,探讨Leadcap温拌剂对SBS改性沥青性能的影响。研究表明,Leadcap温拌剂降低了SBS改性沥青的稠度;低温延度增加,改善了低温抗裂性能;软化点和车辙因子增大,相位角减小,改善了沥青的高温抗车辙性能;布氏黏度减小,对沥青起到了温拌作用,达到了环保节能的效果。     

温拌SBS改性沥青制备及理化性质研究

研究了一种新型温拌剂对沥青的降黏效果及常规性能的影响。制备温拌SBS改性沥青条件为:搅拌转速200 r/min,搅拌时间30 min,温拌剂溶液pH为8,温拌剂浓度6%。结果显示,该温拌剂在一定程度上提高了沥青的软化点和针入度,延度变长,沥青的高低温性能均得到有效改善和提高。     

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。