硅线石材料的预处理及其莫来石化行为

研究了硅线石材料的预处理及其莫来石化行为。结果表明：本文设计的少污染、无需专用设备的酸洗工艺能满足除杂的要求。采用球磨的方法获得的微细硅线石粉料有利于莫来石的转化；借助于X－射线衍射图详细地分析了三种温度下硅线石的莫来石化行为，在低于理论温度1545℃的情况下，已有部分莫来石生成，在1650℃×4h的条件下，可彻底地转化为莫来石和玻璃相，并用HF萃取法测定这一条件下的莫来石转化率。最后，通过合适工艺获得了平均粒径为2．8μm的合成莫来石粉料。     

硅线石及其尾矿利用研究

硅线石属于蓝晶石族高铝矿物,它是一种十分重要的非金属矿物原料。硅线石可以在1545℃时不可逆转化成莫来石和Si O2(方石英),这就是硅线石的莫来石化行为。此固相反应不仅可以合成莫来石瓷,而且相变过程中产生的体积效应可以被用于材料的增韧。本文介绍了硅线石陶瓷化及其应用,并简要介绍了材料制备的工艺。硅线石选矿提纯因工艺不精,得到精矿后的尾矿中硅铝含量依旧很高。因此,对于硅线石尾矿的利用研究意义重大。本文综述了硅线石尾矿的几种应用实例,并简述了硅线石尾矿利用的重要性。     

氧化铝-莫来石复合粉对莫来石烧结行为的影响

将莫来石先驱体溶胶预先引入到硫酸铝水溶液中 ,干燥后经 12 0 0℃煅烧获得氧化铝 -莫来石复合粉料。研究了该粉料与硅溶胶混合获得的混合粉的烧结行为 ,并与氧化铝、莫来石晶种和硅溶胶三相混合获得的混合粉的烧结行为进行了分析比较。其中 ,两种混合粉料均是以理论莫来石组分进行配比 (Al2 O3∶SiO2 =72∶2 8) ,并且两种混合粉中莫来石晶种的质量分数均为 5%。实验结果表明 :前者在 1450℃烧结 2 0min即实现完全莫来石化 ,其显微结构为晶须状莫来石 ;后者在 150 0℃烧结 2 0min实现完全莫来石化 ,其显微结构为针状莫来石     

红柱石原料高温结构演变及抗钾蒸气侵蚀行为研究

红柱石是铝硅系耐火材料重要的原料之一，因完全莫来石化后具有莫来石-高硅氧玻璃相相间的结构而表现出优异的抗碱侵蚀性能。然而，其莫来石化程度与抗碱侵蚀性能之间的关系尚未厘清。为此，本工作以粒度为3～5 mm的红柱石为研究对象，在1 450～1 600℃下热处理红柱石3 h,研究了红柱石的莫来石化过程与结构演变，并采用碱蒸气法研究了抗碱侵蚀行为。结果表明，随着热处理温度的提高，红柱石表面及裂纹附近先转变形成莫来石-高硅氧玻璃相结构，随后莫来石化转变不断向内部发展，直至完全莫来石化。红柱石莫来石化程度不同决定了其不同的抗碱侵蚀行为。1 450℃热处理后的红柱石表面及大裂纹附近形成的莫来石-高硅氧玻璃相复合层较薄，侵蚀以红柱石与钾蒸气直接反应为主，抗碱侵蚀性能较差；1 500℃及以上温度热处理的红柱石表面及大裂纹附近形成了一定厚度的莫来石-高硅氧玻璃相复合层，钾蒸气首先与高硅氧玻璃相反应形成含钾硅酸盐液相，随后该液相对莫来石相产生侵蚀溶解，阻止了碱蒸气对莫来石的直接反应侵蚀，从而使红柱石表现出优良的抗碱侵蚀性能。     

硅线石莫来石化材料在液态模锻模具中的应用

将硅线石莫来石化材料用于制作液态模锻模具中的凹模,并进行了铝合金液态模锻试验。尽管在实际比压值未达到材料的许用比压值时,凹模即遭到破坏,但所获得的铝合金制件表观良好,这说明用硅线石莫来石化材料。作为液态模锻的模具材料是可行的。在试验结果的基础上,对试验中的不足进行了认真地分析,并提出了具体的解决措施。     

氟化铝对红柱石莫来石化的影响

本文主要研究了氟化铝的加入对红柱石矿物转化为莫来石的温度,转化程度以及生成相莫来石的形态的影响.结果表明,加入6wt％氟化铝可以使红柱石矿物在1300℃完全莫来石化;同时氟化铝的加入可以促进莫来石晶体各向异性生长,得到直径为0.5～2.0 μm,长径比为20～40的莫来石晶须,可以用于制备自增韧的莫来石陶瓷或莫来石晶须增强的复合材料.     

硅线石莫来石化材料在液态模锻模具中的应用

将硅线石莫来石化材料用于制作液态模锻模具中的凹模，并进行了铝合金液态模锻试验。尽管在实际比压值未达到材料的许用比压值时，凹模即遭到破坏，但所获得的铝合金制作表观良好，这说明用硅线石莫来石化材料作为液态模锻的模具材料是可行的。在试验结果的基础上，对试验中的不足进行了认真地分析，并提出了具体的解决措施。     

南非红柱石细粉的烧结行为和莫来石化研究

采用南非红柱石细粉(粒度≤0.088mm)为原料,粉体在200MPa下成型为36mm×10mm试样,选择煅烧温度为1200～1600℃(温度间隔50℃),研究了南非红柱石细粉的烧结行为。通过对试样烧后线变化率、体积密度、显气孔率及XRD分析数据进行处理,分析了红柱石分解和莫来石化反应的行为特征。结果表明:1200℃左右已有莫来石生成;1500℃红柱石分解完全。随着温度的升高,红柱石和莫来石两者的消长主要出现在1300～1400℃,而反应过程有如下先后顺序:材料膨胀,红柱石分解,莫来石生成。温度低于1400℃,莫来石化反应膨胀和基质烧结同时存在,出现局部膨胀和局部烧结排除气孔共存的现象,导致显气孔率的变化趋势与烧后线变化率及体积密度的变化趋势不对应。高于1450℃,液相促进烧结起主导作用,材料大幅度收缩。1400℃煅烧后试样的线收缩率最小。     

莫来石-堇青石陶瓷窑具材料的性能及显微结构

研究了红柱石骨料的莫来石化作用及添加剂SiC的加入量、合成莫来石的引入和烧成温度对莫来石-堇青石窑具材料性能及显微结构的影响。结果表明 ,在 1380℃ 4h下烧成时 ,红柱石的莫来石化作用能大大改善材料的烧结性能 ;加入 4 %的SiC可提高材料的物理性能 ;部分合成莫来石的加入可克服红柱石在莫来石化过程中的不足 ,强化材料的组织结构 ,提高材料的物理性能     

用红柱石生成莫来石

在1250－1700℃之间，用X射线衍射技术研究了伊朗精红柱石在添加与不添加氧化铝粉情况下生成莫来石的变化过程。该红柱石在1600℃经过2h的加热后，被完全转化为由莫来石构成的、作为主相和非晶相的复合物。红柱石的粒度分布影响了在1500℃下煅烧的粉料的莫来石化。     

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.     

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.     

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。     

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。