泡沫法制备莫来石轻质隔热材料及性能

采用红柱石、刚玉、水泥、粘土、硅微粉为原料,加入减水剂、硅溶胶、泡沫及水,通过改变泡沫的加入量在五种不同温度下烧成制备莫来石质轻质隔热材料,测试试样的容重、气孔率、气孔种类和孔径、常温耐压强度、物相组成和显微结构。采用泡沫法制备的轻质隔热材料试样外观致密,内部气孔分布均匀。试样的主晶相为莫来石相,1400℃烧成试样的烧后线变化和常温耐压强度随容重的增加成线性增加;显气孔率逐渐减小,闭口气孔率基本无变化,大概为3%。     

基于高岭土制备轻量微孔莫来石骨料结构与性能研究

以高岭土细粉和α-Al2O3微粉为主要原料,采用原位分解法制备轻量微孔莫来石骨料,研究了铝硅摩尔比及热处理温度对轻量微孔莫来石骨料结构与性能的影响.结果表明:经过1400～1600℃热处理后,富铝莫来石试样中除主要物相莫来石相外,还残余一定量刚玉相,接近理论莫来石组成试样及富硅试样均仅检测到莫来石相;所制备的轻量骨料孔径分布主要集中于0.1 ～4 μm范围,均具有微孔结构;随着热处理温度的升高,骨料的体积密度上升,显气孔率下降,耐压强度上升;经1500℃热处理后,富铝试样体积密度为2.49 g/cm3、显气孔率为25.6％、耐压强度为146 MPa;接近理论莫来石组成试样及富硅试样体积密度均小于1.95 g/cm3、显气孔率大于38.0％,1000℃时导热系数均小于0.77 W/(m·K).     

硅线石含量对轻质莫来石-刚玉耐火材料的显微结构与性能的影响

以多孔球形莫来石为骨料,板状刚玉细粉、硅线石和粘土为基质,经1400 ℃、1500 ℃和1600 ℃保温3 h烧成,制备了四组轻质莫来石-刚玉耐火材料.采用X-射线衍射仪(XRD)和扫描电子显微镜(SEM)对试样的物相组成和显微结构进行表征,研究了烧成温度及硅线石含量(4%、6%、8%和10%)对试样常温物理性能和显微结构的影响.结果表明:(1)当硅线石含量不变时,随着烧成温度的升高,试样的显气孔率逐渐减小,体积密度逐渐增大,线收缩率逐渐增加,常温耐压强度先降低后升高;(2)当硅线石的含量从4%增加到8%时,经1400 ℃烧后,试样的显气孔率和体积密度变化不大,当硅线石含量超过8%时耐压强度显著下降;经1600 ℃烧后,随硅线石含量的增加,试样的体积密度减小,强度降低,线收缩率也由2.5%减小到1.5%;(3)当硅线石含量为6%、烧成温度为1400 ℃时,试样的线收缩率为0.86%,耐压强度为36.1 MPa,热导率为0.249 W/(m·K)(300 ℃),试样基质中气孔的d50为46.7 μm.     

蓝晶石基微孔针状莫来石的制备、结构及性能研究

以蓝晶石和γ-Al_2O_3为主要原料,采用注浆成型技术和反应烧结工艺制备出气孔率高、强度高、孔径小、并具有针状网络结构的微孔莫来石陶瓷材料。研究了γ-Al_2O_3加入量对烧后试样物相组成、显微结构及性能的影响。结果表明:针状莫来石可对基体起强韧化作用,并使气孔的有效半径微细化。随着γ-Al_2O_3加入量的增多,试样中原位生成的针状莫来石先增多且后减少,致使试样的显气孔率和常温机械强度先升高后降低、平均孔径先减小后增大。     

多孔莫来石陶瓷的制备和性能研究

多孔莫来石是以石墨为孔隙形成剂、由Al2O3和SiC混合粉原位反应合成的。本文研究了烧成温度对气孔率、强度、孔径以及比表面积的影响。研究表明,随着烧成温度的升高,试样强度提高,孔径增大,而气孔率和比表面积减小。由于形成了颈部发育良好的细晶粒微观结构,气孔率为32.4%的试样其平均强度可达到106MPa。同时,制备了气孔率为61%的多孔莫来石陶瓷,其具有相当高的比表面积(12.4m2·g-1),能很好的阻止裂纹扩展,具有很好的抗热震性。     

无机盐/石英基复合相变储能材料多孔陶瓷基体的制备

以石英为骨料,钾长石为高温粘结剂,木炭为造孔剂制备无机盐/石英基复合相变储能材料用的微米孔石英多孔陶瓷基体,采用正交实验法系统研究了骨料颗粒粒度、造孔剂粒度、造孔剂含量、高温粘结剂含量及烧成温度对石英多孔陶瓷的显气孔率和抗折强度的影响.研究结果表明,影响石英多孔陶瓷抗折强度的最主要因素是长石含量,其次是骨料粒度和造孔剂粒度;影响石英多孔陶瓷显气孔率的主要因素是造孔剂含量.制备微米孔石英多孔陶瓷的优化配方和工艺是:石英、木炭和长石均过325目筛,三者质量比为7:2:1,烧成温度为1270f,保温时间为1h.该陶瓷具有以下优良的性能:显气孔率为55.12％,体积密度为1.14 g,/cm3,抗折强度为3.14 MPa,抗压强度为7.12 MPa,平均孔径为13.87 μm且孔径分布范围较窄,96％的气孔孔径在9～21 μm之间.     

莫来石/SiC复相多孔陶瓷的制备及性能研究

用高岭土、Al2O3粉和SiC粉末为原料,活性碳为造孔剂制备莫来石/SiC多孔陶瓷.测定了试样的显气孔率、气孔孔径分布和抗弯强度,并分别用XRD和SEM分析晶相组成和断面显微结构.结果表明:莫来石的理论设计质量的分数小于10%时,莫来石/SiC多孔陶瓷的显气孔率随其设计量的增多而急剧降低;莫来石理论设计量继续增加时,试样显气孔率缓慢降低并趋于稳定.气孔孔径随莫来石设计量的增加而急剧减小.抗弯强度随莫来石设计量的增加而先增大,在莫来石理论设计量为20%时达到最大值,此后逐渐降低.SEM分析结果表明:与其他试样相比,莫来石设计量为40%的试样中存在较多的多孔"微区".     

锆莫来石对Al2O3-ZrO2-C材料性能的影响

以电熔白刚玉、锆莫来石、鳞片石墨、SiC粉和酚醛树酯为原料,通过改变锆莫来石的加入量和粒度制备了7种不同的A l2O3-ZrO2-C试样,主要研究了锆莫来石加入量和试样的粒度组成对A l2O3-ZrO2-C材料的体积密度、显气孔率、常温耐压强度、气孔孔径分布和透气度等性能的影响。结果表明:1)锆莫来石加入量对A l2O3-ZrO2-C材料的体积密度、显气孔率、耐压强度、气孔孔径分布和透气度都有一定的影响,但影响都不大;2)试样的粒度组成对A l2O3-ZrO2-C材料的体积密度和透气度的影响较大,但对显气孔率、常温耐压强度、气孔孔径分布的影响较小。     

稻壳低温制备多孔氮化硅陶瓷

以稻壳为原料,碳热还原法常压条件下合成出Si3N4粉体,进而模压成型,在低温下成功烧成了多孔氮化硅陶瓷.采用Archimedes法、三点弯曲法测量了烧结试样的密度、气孔率及抗弯强度.通过XRD测定了烧结试样的物相组成,并用SEM观察其显微形貌.结果表明:在1450℃到1550℃内均能烧成多孔氮化硅陶瓷,随着温度的升高,试样的气孔率逐渐降低,抗弯强度逐渐增强.1450～1500℃烧成试样的显气孔率为55.51％ ～35.15％,其抗弯强度为23.74 ～86.85 MPa,主要物相为β-Si3N4.     

烧结温度对莫来石多孔陶瓷结构与性能的影响

以含锆硅线石为主要原料,α-Al₂O₃粉为辅料,改性淀粉为造孔剂,原位烧结制备了莫来石多孔陶瓷试样。研究了烧结温度(1 400～1 600℃,间隔50℃)对试样物相组成、显微结构及性能的影响。结果表明：1)随烧结温度的升高,试样中莫来石衍射峰的强度逐渐增强,莫来石晶粒逐渐发育长大,其外观呈现明显的台阶状形貌,符合二维成核生长机制。2)随烧结温度的升高,烧后试样的体积密度呈先减后增趋势,而显气孔率和线变化率的变化趋势则与之相反,常温耐压强度则呈逐渐增大趋势。3)当烧结温度为1 550～1 600℃时,试样综合性能较佳,莫来石晶粒发育长大并致密结合,适于在高温下使用。     

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.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、环氧树脂、不饱和聚酯树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍。     

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。