尿素络合法生产液蜡的影响因素考察

尿素络合法是生产液蜡的一种重要工艺,主要是依靠尿素易与正构烷烃络合,而较难与非正构烷烃络合的原理实现正构烷烃的提取。在整个过程中,存在很多因素影响反应效果。以直馏柴油为原料,对尿素络合过程中的各因素开展趋势试验,总结各因素对产品纯度的影响规律并分析产生这些规律背后的原因。通过试验发现:液蜡制备过程中的各因素对液蜡性质的作用机制是通过影响尿素与不同碳数正构烷烃的反应程度以及影响尿素与正构/非正构烷烃的反应程度来影响液蜡产品纯度;溶剂洗涤过程的温度和强度也会对液蜡的纯度和收率产生影响。     

PB试验和BBD响应面优化酶解鱼鳞制备抗菌肽工艺

以酶解液的多肽含量和抑菌活性作为考察指标,采用酸性蛋白酶酶解制备草鱼鱼鳞抗菌肽。在单因素的基础上,运用PB试验设计进行影响因素的显著性筛选,确定出显著性影响因素为pH、温度和时间,进而通过BBD试验得到草鱼鱼鳞抗菌肽制备的最佳工艺条件为:pH 2.72、40.22℃、97.33min,在该条件下酶解液对金黄色葡萄球菌的抑菌圈直径为18.49mm,对大肠杆菌的抑菌圈直径为17.31 mm。结果表明,利用酸性蛋白酶酶解制备草鱼鱼鳞抗菌肽是行得通的,为草鱼鱼鳞等下脚料实现低值原料高值化提供了新的思路。     

外加晶种对钛液水解反应中粒径的影响及机理探讨

硫酸法生产钛白粉工艺中水解过程对最终产品质量有着重要的影响。为了探究外加晶种这一水解条件对水解产物粒径分布的影响,选用工业中的钛液为原料,通过试验考察了不同的晶种加量,不同钛碱比制备的晶种及晶种晶粒的大小对水解三个阶段水解产物粒径的影响。结果表明晶种加量对三个不同水解阶段的粒径影响最大,而其他因素对钛液水解影响不大。同时结合拉曼光谱提出了新的水解机理。这些结果将用于指导工业生产。     

银杏叶总黄酮的提取分离工艺研究

采用紫外分光光度法测定银杏叶中总黄酮的含量;通过单因素试验考察提取溶剂、料液比、浸提时间、浸提温度对银杏黄酮得率的影响,并用正交试验确定了银杏黄酮提取的最佳工艺;通过不同型号吸附树脂对银杏黄酮吸附效果的比较,确定了吸附树脂的型号,并考察了不同洗脱液的洗脱效果,筛选出最佳洗脱液。试验得到最佳制备工艺为:以50%乙醇为提取剂,料液比为1∶20,浸提时间为6.0h,浸提温度为90℃;以D101型大孔树脂对提取液进行吸附纯化,用30%乙醇进行洗脱分离。利用此工艺制备的银杏叶提取物中黄酮含量达35%,银杏酸含量低于5×10-6。     

茶油枯——木棉花洗发水的研制与性能研究

研究以茶油枯粗提液、木棉花粗提液为主要原料,研制一种草本洗发水。通过实验筛选出基本配方,考察了茶枯饼提取液对洗发水调理性能的影响,以及木棉花粗提液对洗发水配伍性能的影响,理化测试结果,各指标达到国家标准,与国内知名洗发水和国外品牌洗发水相比,成本低,天然原材料易得,具有去屑、止痒、清热、祛风除湿药理作用。     

水性多彩弹性外墙涂料的制备研究

重点考察了影响凝胶粒子稳定性的一些主要因素,确定了凝胶粒子的制备路线,通过选择合适型号及用量的凝胶材料、无机保护胶、水性颜料浆以及硅丙弹性乳液,并对产品性能进行综合测试及评价后,制备出了一种综合性能优异尤其是贮存稳定性好的水性多彩弹性外墙涂料。     

钛合金碱性阳极氧化工艺参数的研究

钛合金表面处理对胶接件性能有显著的影响。通过正交试验考察了槽液温度、恒定电压、处理时间和阴阳电极板距离对钛合金胶接前表面处理效果的影响,并优化了实验工艺参数。试验结果表明,槽液温度对处理效果的影响最显著,其余三个因素次之。在最佳工艺条件下制备的钛合金胶接件获得了良好的性能。     

高铝煤矸石制备超细氧化铝和硅酸钠联产工艺

利用盐酸酸浸法从煤矸石中浸取氧化铝,考察了固液比、反应温度、盐酸浓度、反应时间、煤矸石活化时间及活化温度等因素对氧化铝浸取率的影响,通过正交试验确定了最佳的工艺条件,使氧化铝浸取率达到84%左右;研究不同分散剂对氧化铝颗粒硬团聚的抑制作用,利用SEM、XRD对原料及制备的氧化铝进行了表征,表明制备出了高纯度、高分散性的超细氧化铝;同时还研究了氢氧化钠浓度对联产工业液体硅酸钠模数的影响。     

低毒树脂改性氯丁胶粘剂的研制

以氯丁橡胶为主要基体,与经过预反应的胶液进行反应,通过设计的正交实验来分析预反应液中各因素的影响作用。选用低毒性的溶剂,制备了一种低毒树脂改性氯丁胶粘剂。剪切强度(皮革-皮革)的实验结果表明,各因素影响作用由大到小依次为:对叔丁基酚醛树脂与氧化镁的质量比、催化剂的加入量、氯丁橡胶与对叔丁基酚醛树脂的质量比、溶剂的选取、溶胶温度。于较佳的条件下所制备的低毒胶粘剂性能良好,剪切强度可达4.3MPa。     

填料对超薄切割砂轮性能的影响

介绍了不同因素对树脂超薄切割砂轮性能的影响。通过正交实验法能够以较少的试验次数优选出最佳配方,并找出各种因素对超薄树脂切割砂轮性能的影响次序。研究表明:填料是影响树脂超薄切割砂轮的锋利度和磨削效率的最主要因素,其次是磨料,再者是结合剂。优选的配方为:酚醛树脂17%、磨料69%(棕刚玉与白刚玉质量比为3∶1)、石膏6%、冰晶石8%。此配方制备的树脂超薄切割砂轮可使锋利度和磨削效率分别提高76.34%和10.07%,并具有良好的应用前景。     

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。