M40J/EC复合材料的温湿效应

用湿法缠绕技术制作了高模量，高强度石墨纤维增强高韧性低吸湿环氧树脂（M40J／EC）预浸料，对热压罐固化的M40J／EC复合材料的室温，高温干态和湿态力学性能进行了研究。与高模量石墨纤维／酚醛环氧树脂（40／4211）得合材料相比，M40J／EC复合材料的各项力学性能均有很大程度的提高，且有优异的耐湿热性能，在130℃干，湿态下，其弯曲强度，弯曲弹性模量和层间剪切强度的保持率较高。     

端烯化合物改性双马来酰亚胺树脂

BMI(DDM型双马来酰亚胺)经VE(环氧丙烯酸酯)改性,两者重量比为1:1时,加适当促进剂,可以在改善BMI成型工艺性同时保持基体优良的耐热性和耐湿/热性能。基体热变形温度285℃。T300增强单向板干态250℃下层剪强度和弯曲强度保持率分别为60％和63％。沸水煮24小时后,室温下层剪和弯曲强度保持率分别为90％和94％,150℃、200℃层剪强度保持率分别为71％和61％。     

CF／5228复合材料研究

用湿法缠绕技术制作了CF/5228预浸料,对热压罐固化的CF/5228复合材料的室温、高温干态和湿态力学性能进行了研究。与其它复合材料相比,M40J/5228复合材料的各项力学性能均有很大程度的提高,且具有优异的耐湿热性能,在130℃干态和湿态下,其弯曲强度、模量和层间剪切强度的保持率较高。     

改性环氧树脂的制备及其性能研究

采用二苯甲烷型双马来酰亚胺(BDM)和二甲基二乙氧基硅烷(DMDES)共同改性双酚A型环氧树脂(EP/CYD-127)/芳香胺(DDM)固化体系,并对改性后的环氧树脂进行力学性能和热学性能分析。结果表明改性后的环氧树脂浇铸体具有优良的韧性和耐热性。当BDM质量分数为5%(DMDES质量分数为4%)时,改性后环氧树脂弯曲强度达到92.11 MPa,冲击强度达20.202k J/m;热失重率50%时温度到达399.992℃,残炭率为17.88%。     

聚酰胺酰亚胺对BMI/DP共聚树脂的增韧研究

以DP(二烯丙基双酚A)为BMI(双马来酰亚胺)的共聚改性剂,制备BMI/DP共聚树脂;然后以PAI(聚酰胺酰亚胺)为增韧改性剂,制备PAI增韧改性BMI/DP共聚树脂。研究结果表明:当w(PAI)=3%(相对于共聚树脂质量而言)时,改性树脂具有较好的增韧效果;此时,其冲击强度(11.81 kJ/m2)提高了19%以上,KIC(临界应力强度因子)值(1.45 MPa.m0.5)和GIC(临界应变能释放率)值(351.4 J/m2)均比增韧前提高了30%以上,表现出较好的断裂韧性,并且其断面为典型的韧性破坏;其Tg(玻璃化转变温度)达到了252.5℃,5%热失重温度仍超过405℃,说明其耐热性几乎没有下降。     

氰酸酯树脂及其碳纤维复合材料研究

E5 1环氧树脂改性双酚A型氰酸酯树脂 (BADCy)体系的力学和热性能的研究表明 ,5 % (质量分数 ,下同 )的E5 1环氧树脂可使BADCy的弯曲强度和冲击强度分别由原来的 95 .6MPa和 9.2 4kJ/m2 提高到 117.8MPa和12 .5 8kJ/m2 ,热变形温度仅下降 8℃。碳纤维 /BADCy复合材料的扫描电镜和力学性能测试结果表明 ,纤维的表面形态对界面粘结效果有较大影响 ,三种复合材料界面的粘结强弱顺序是T3 0 0 /BADCy >M 40 /BADCy >M 40J/BAD Cy。水煮 10 0h对三种碳纤维复合材料的弯曲性能影响不大 ,但对层间剪切强度的影响明显 ,其中M 40J/BADCy的层间剪切强度保持率只有 84.2 % ,而T3 0 0 /BADCy的强度保持率高达 92 .5 %。热冲击和紫外线辐照实验研究表明 ,-3 0℃ / 11h～ 15 0℃ / 11h的 2 0次热交变及总剂量为 1× 10 9J/m2 的紫外线照射对BADCy基碳纤维复合材料的力学性能影响很小 ,三种复合材料的弯曲强度、弯曲模量和层间剪切强度的保持率均大于 90 %。     

改性氰酸酯树脂体系力学性能的研究

采用环氧树脂(E-51)与氰酸酯树脂共聚以改善氰酸酯树脂的韧性，研究了环氧树脂的加入量，后处理温度、湿热老化以及紫外光老化等条件对改性后树脂体系力学性能的影响规律，采用扫描电子显微镜对断口形貌进行了分析。结果表明环氧树脂可以明显改善氰酸酯树脂的韧性，环氧树脂含量为30％(质量百分数，下同)的体系的冲击强度和弯曲强度分别比改性前提高了100％和50％随环氧树脂用量的增加，改性树脂的冲击强度和弯曲强度提高，树脂表现为明显的韧性断裂；改性体系经2000℃、后处理2h的力学性能最佳；湿热老化和紫外光老化都使改性树脂体系的冲击强度和弯曲强度降低，而后者的影响较弱，当环氧树脂用量低于30％时冲击强度和弯曲强度的保持率均高于95％。     

新型柔性固化剂的合成与性能表征

环氧树脂具有优良的热稳定性、电绝缘性能和物理、机械性能,但其固化后较脆、不耐冲击和容易应力开裂。本文提出在合成一种新型柔性环氧树脂固化剂,通过与环氧树脂固化反应后提高环氧树脂韧性的改性思路,达到提高环氧树脂韧性而不降低树脂固化物的强度和模量的目的。研究结果表明,当柔性固化剂的用量为质量百分含量在10%~15%之间时韧性达到最大。对于使用柔性固化剂固化环氧树脂,当柔性固化剂的用量为环氧树脂质量百分含量的10%时达到最大值,冲击韧性和断裂韧性分别比纯环氧树脂提高了33.3%和96.3%。柔性固化剂的用量为环氧树脂质量百分含量的10%时,在-50℃时冲击韧性大小为19.5k J·m-2,而此时纯环氧树脂的冲击韧性仅为7.96k J·m-2。     

改性双马树脂/碳纤维复合材料体系耐湿热性能研究

对5428/T700复合材料的吸湿率、不同吸湿条件下的玻璃化转变温度及高温湿态力学性能进行了研究。结果表明,5428/T700体系具有较低的吸湿率,经70℃去离子水水煮72 h,吸湿率为0.5%,饱和吸湿率(水煮360 h)为0.8%。而且随着复合材料吸湿量的增加,其Tg下降缓慢;5428/T700复合材料在干态170℃下的弯曲性能和层间剪切性能保持率在70%以上,在湿态150℃下的弯曲性能和层间剪切性能保持率在50%以上;5428/T700复合材料在湿态150℃下的开孔压缩强度保持率在80%以上。     

烯类化合物共聚改性双马来酰亚胺树脂的研究

针对环氧树脂改性双马来酰亚胺（BMI）树脂耐热性有较大降低的缺点,用端烯类化合物共聚的方法改性BMI树脂.采用的烯类共聚单体有3,3＇-二烯丙基-4,4＇二酚基丙烷（DABPA）、邻苯二甲酸二烯丙基酯（DAP）和环氧丙烯酸酯（VE）.改性BMI树脂浇铸体及其复合材料的性能研究表明,国产原料BMI/DABPA树脂的韧性低于Ciba-Geigy的XU292,但固化后处理温度降低了20℃.采用二胺扩链改性可提高BMI/DABPA树脂的韧性,适量的DAP能改善BMI/DABPA树脂的工艺性.VE改性BMI树脂的固化活性较高,最高固化温度可降低到180℃.VE改性BMI树脂与碳纤维的界面粘接良好,复合材料具有较高的耐热性,200℃下弯曲强度保持率在70%以上,短梁剪切强度保持率在60%以上.     

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.     

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.     

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。     

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.     

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.     

基于ATRP法制备的触角状亲水性羟胺树脂的吸硼性能的研究

以大分子引发剂氯乙酰化聚苯乙烯微球(PS-acyl-Cl)经原子转移自由基聚合(ATRP)法引发丙烯酰胺(AM)和甲基丙烯酸缩水甘油酯(GMA)单体的共聚接枝,制得一种触角状亲水性环氧载体(PS-acyl-g-P(AM-co-GMA)),再经二乙醇胺(DEA)的环氧基开环胺化反应,得到一种含多个-NCH2CH2OH螯合配基的多齿-五元螯合环的触角状亲水性羟胺树脂(PS-acyl-g-P(AM-co-GMA)-DEA)。将此树脂用于硼吸附研究,结果表明,PS-acyl-g-P(AM-co-GMA)-DEA树脂对硼的吸附满足Langmuir方程,为单分子层吸附;饱和吸附量约为37.7 mg·g-1,且树脂5 min即可达到吸附平衡,与其它已报道的吸硼树脂相比,该树脂具有更高的吸附量和吸硼速率。吸附动力学研究表明,树脂吸附硼的过程主要由颗粒扩散过程控制。重复使用5次后该树脂的吸附量基本不变,解吸率均在90%以上,重复使用性能良好。