低成本快干型淀粉胶的研究

选用新型的催化剂,探讨了各种因素对淀粉氧化和糊化的影响,结果表明,制备淀粉胶的最佳条件为:40%的淀粉乳中加入5%的氧化剂,在催化剂存在时于58℃下氧化30min,加入10%的NaOH糊化,加填料、加水调节固含量至12%(均以淀粉质量为基准),合成的玉米淀粉胶粘剂成本低、干燥快,有望彻底取代泡花碱。     

新型氧化淀粉胶粘剂的制备

以玉米淀粉为原料,采用氧化改性法,并配以糊化剂、胶联剂及适量钠基蒙脱土,研制出稳定氧化淀粉胶粘剂。研究了氧化剂、糊化剂、胶联剂及钠基蒙脱土用量对淀粉胶粘剂粘结性能的影响。结果表明,氧化淀粉胶粘剂的最佳配方为:高锰酸钾的用量为0.3%,氢氧化钠的用量为0.9%,硼砂的用量为0.3%,钠基蒙脱土的用量为4%。     

玉米淀粉胶粘剂的改性研究

以玉米淀粉为主要原料 ,通过预糊化、氧化、加碱糊化进行化学改性 ,并加入稳定剂可制备固含量高、贮存稳定性好 ,具有一定初粘力和透明性的改性淀粉胶粘剂。本论文主要研究了改性玉米淀粉胶粘剂的主要成分配比及工艺条件对产品性能的影响。结果表明 :淀粉氧化前是否进行预糊化处理、氧化剂的用量、体系pH值、加碱糊化时碱液用量、稳定剂的种类和用量等对改性玉米淀粉胶粘剂性能影响较大。     

H2O2氧化法冷制淀粉胶的生产工艺研究

以玉米淀粉为主料,在催化剂作用下,经双氧水室温氧化、糊化、交联,最终得到一种成本较低、性能优良的淀粉胶粘剂.通过正交试验,确定优化工艺条件为:淀粉乳浓度为15%(含50g玉米淀粉),氧化反应时间为120min,催化剂0.5g,糊化时间30min,硼砂1g,氢氧化钠6g.     

聚乙烯醇改性固体淀粉胶粘剂的研制

介绍新型固体淀粉胶的制备方法。以淀粉为主要原料，经加热催化分步氧化，再加入聚乙烯醇合成树脂改善其性能，然后用硬脂酸钠作为赋型剂。制得的淀粉胶剪切强度比泡花碱高0.01MPa。     

氧化淀粉改性脲醛树脂的研究

用玉米淀粉为原料,通过H2O2氧化制成氧化淀粉,糊化后加入到脲醛树脂中,制得不同氧化淀粉含量的改性脲醛树脂,与不含氧化淀粉的脲醛树脂胶粘剂的性能对比,具有游离甲醛、羟甲基含量低和粘合强度好等优点,而且成本也大大降低,表明可有效地改善脲醛树脂胶粘剂的综合性能。     

氧化条件对淀粉/丙烯酸共聚物粘接性能的影响

以双氧水(H2O2)为氧化剂、硫酸铜(CuSO4)为氧化催化剂,玉米淀粉经氧化、糊化和AA(丙烯酸)接枝改性后,制得淀粉/AA接枝共聚物;然后以此为瓦楞纸板生产用淀粉胶粘剂的载体,以淀粉氧化过程中的pH、催化剂含量、氧化剂含量、氧化时间和氧化温度为试验因素,以接枝淀粉胶粘剂/瓦楞纸板的粘接强度和边压强度为考核指标,采用单因素试验法优选出制备该胶粘剂的最佳工艺条件。结果表明:当pH=10、V(0.1 mol/L CuSO4)=0.6 mL、w(H2O2)=0.6%、氧化时间为20 min和氧化温度为30℃时,接枝淀粉胶粘剂具有相对最好的粘接性能,相应接枝淀粉胶粘剂/瓦楞纸板的粘接强度和边压强度相对最大。     

冷制高强快干淀粉胶粘剂

介绍了一种以淀粉为主要原料,在复合催化剂作用下,经双氧水室温氧化并添加高强快干添加剂和其他助剂,制备高强快干淀粉胶的方法,讨论了对淀粉胶性能的影响因素及其简要的作用机理,确定了能够满足最佳上机要求的配方。应用本方法制出的胶粘剂,通过中试制板,证明该胶具有干燥速度快、强度高等优点。     

MF改性的淀粉胶黏剂的合成与性能研究

对玉米淀粉进行氧化、聚合处理,再使用MF改性,制得防水高黏型淀粉胶粘剂。同时采用正交实验法查验了淀粉糊化温度、NaClO相对于淀粉的质量比、PVA溶液质量分数和MF相对于淀粉的质量比对胶黏剂性能的影响。得到一款防水高黏型淀粉胶黏剂的制备条件为:PVA质量分数20%,淀粉糊化温度55℃,MF投料比1.25,NaClO投料比1%。在此条件下胶黏剂粘度达到GB/T 2794-1995的标准,耐水性能符合QB/T l094—1991的标准。     

交联氧化淀粉胶黏剂的制备及性能研究

采用交联氧化法,先用高锰酸钾氧化可溶性淀粉制得低取代度氧化淀粉,再用戊二醛交联成交联氧化淀粉主剂,最后在高温无水条件下加入甲苯二异氰酸酯（TDI）得到氨基甲酸酯交联氧化淀粉胶黏剂。初步探讨了交联氧化机理,分析了交联氧化淀粉胶黏剂的影响因素,利用红Pb（IR）、扫描电镜（SEM）对其进行了表征,对产品的各项性能进行测试研究。结果表明,氧化程度影响其粘结性能,低取代度氧化淀粉粘结性好,且有利于淀粉进一步交联反应,交联提高淀粉耐水性,TDI能够显著提高氧化淀粉的耐水性和粘结强度。当淀粉浓度为10％,高锰酸钾用量为0．0290g,戊二醛用量为2mL,TDI用量为1mL时,制得的交联氧化淀粉胶黏剂的耐水时间为24d。     

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。