规模化制备钙基复合载氧体的性能研究

采用规模化制备方法得到了两种钙基复合载氧体,并分别在冷模流化床和固定床上考察了其机械强度和循环反应性能。结果表明:制备的两种复合载氧体各组分分布均匀,机械强度较好。通过对磨损前后粒度分布变化和时变规律的比较,得到的CaAlFe载氧体耐磨损性能较好,510 min后磨损率仅为3.83%。热重实验表明,CaAlNi载氧体同煤之间的反应在12 min内完成,反应速率稍快,但CaAlFe载氧体同煤的反应更彻底。选择CaAlFe载氧体进行了5次还原-氧化循环实验,固体产物和气体产物分析表明CaAlFe载氧体具有良好的持续循环反应能力。因此,所研究规模化制备的CaAlFe载氧体适用于工业生产。     

化学链重整制氢NiO-CeO2/γ-Al2O3复合载氧体的性能

采用浸渍法制备了结构型NiO-CeO₂/γ-Al₂O₃复合载氧体，研究了Ni/Ce质量比对化学链重整制氢反应性能的影响。固定床反应器实验表明，随着Ni/Ce质量比的降低，氢气的选择性先升高后降低，比例为3∶1时氢的选择性和氢产物浓度最高。循环实验测试表明，3∶1载氧体在20个循环后仍保持催化活性，积炭量最低。XRD结果表明，加入CeO₂后有固溶体形成，增加了氧空位，在一定程度上减弱了NiO与γ-Al₂O₃之间的相互作用，提高了活性物质的分散度。进一步分析XRD结果发现3∶1载氧体粒径最小，更有利于制氢反应。SEM分析发现，经过20次循环3∶1载氧体颗粒的微观形貌变化相对较小。进一步的固定床实验研究表明较高的反应温度有利于制氢反应，800℃时3∶1载氧体的性能表现最佳；此外3∶1载氧体在较高水碳比下仍能保持较高的产物选择性。     

CuO修饰的赤泥载氧体废弃活性炭化学链燃烧

以拜耳法赤泥为基体,采用浸渍法制备了CuO修饰的赤泥载氧体（Cu0.5RM1、Cu1RM1）。利用SEM-EDSmapping、XRD对其进行物化表征,并在高温流化床反应器及热重分析仪中考察了赤泥载氧体的废弃活性炭化学链燃烧特性。结果表明,浸渍法可准确制备定量CuO修饰的赤泥载氧体;相比于纯赤泥载氧体,CuO修饰的赤泥载氧体具有化学链燃烧载氧体与化学链氧解耦燃烧载氧体的双重特性,能够加快碳转化速率,有效提高出口气体中CO₂浓度;Cu1RM1反应活性较高,875℃为其较优的反应温度,此时t₉₅为28min,出口气体中CO₂浓度为92.9%（体积分数）,燃烧效率达93.0%。10次循环实验表明Cu1RM1载氧体具有相对稳定的循环反应特性。     

K_2CO_3修饰钙基载氧体的煤化学链气化反应特性

以膨润土(Bentonite)为载体,采用机械混合-浸渍法制备了Ca SO4-K2CO3/Bentonite(Ca KBen)复合载氧体。在流化床反应器中,以水蒸气作为气化、流化介质,考察复合载氧体Ca KBen与不同煤种的化学链气化反应特性,并对该载氧体的循环特性、作用机理及气化动力学方程进行了研究。结果表明:复合载氧体Ca KBen适用于不同煤种的化学链气化过程。900℃时,与纯煤气化相比,Ca KBen化学链气化的碳转化率提高17.88%,反应时间缩短10 min,复合载氧体Ca KBen表现出良好的反应活性和催化性能。十次循环实验过程中,冷煤气效率稳定在85%以上,表明复合载氧体Ca KBen具有良好的循环特性。XRD、SEM分析表明十次循环实验后,钙基载氧体的晶相结构稳定,主要以CaS O4形式存在,K+主要以K2CO3形式存在,载氧体表面变得疏松多孔,该结构有利于化学链气化反应的进行。活性位扩展模型很好地体现了复合载氧体Ca KBen与煤化学链气化的动力学规律,验证了气化过程中CaS O4与K2CO3具有协同作用。     

红砖掺杂改性白云鄂博铁精矿载氧体性能

采用机械混合法,添加建筑固废红砖粉末制备改性白云鄂博铁精矿载氧体,通过热重分析仪和管式炉实验,分析红砖粉末添加量对CO化学链燃烧性能优化效果,并通过扫描电子显微镜、X射线衍射、比表面积分析以及动力学分析等表征手段分析其机制。结果表明,通过DTG曲线可以看出白云鄂博铁精矿载氧体与CO的反应温度基本都高于800℃,红砖粉末改性载氧体可以提升化学链燃烧反应速率,加快反应进程,特别是2.5%红砖改性样品,在950℃下反应效果是最优的,CO₂产率达到了87%;通过对程序升温实验数据进行动力学分析,发现红砖粉末可以缩短其与CO的反应时间,加快反应进程,并且基于循环反应实验,改性载氧体表现出了更稳定的碳转化率。其反应能力的提升和循环稳定性的加强主要是由于红砖粉末使载氧体具有更高的比表面积和孔隙结构所致。     

草木灰水溶液改性的天然贫铁矿载氧体的反应性能

化学链燃烧是一种基于CO_2零排放理念的无焰燃烧技术,能够提高CO_2捕集效率。本文选用一种天然贫铁矿作为载氧体,在热重分析仪上采用CO作为还原气考察了其反应特性。为了减轻载氧体表面的烧结情况,本文提出了采用草木灰水溶液对天然贫铁矿载氧体进行改性,并对改性后载氧体进行短时间、多次数氧化还原循环实验研究;考察了反应器温度对改性前后的载氧体反应特性影响。实验结果表明:天然贫铁矿在15次氧化还原循环反应中展现了一定的循环稳定性,但载氧体的还原程度和反应速率较低;改性后的载氧体还原程度更深、反应速率更快,且保持了良好的反应活性。载氧体在100次的氧化还原循环中出现粉化团聚现象,导致轻微的质量损失。XRD和SEM的分析结果表明生物质灰中的K元素在反应中与铁矿石中的物质生成了新的化合物,增大了载氧体的比表面积,提高了载氧体的还原反应活性。载氧体表面没有出现明显的烧结团聚现象。     

改性BaFe2O4载氧体生物质化学链气化特性

以溶胶凝胶法制备了BaFe₂O₄载氧体以及Ni、Ce、K修饰的BaFe₂O₄载氧体,筛选出最佳载氧体为10%(质量)K修饰的BaFe₂O₄载氧体(10K-BF),探究了不同反应条件对其性能的影响,通过H₂-TPR、XRD、SEM、BET对载氧体表征。实验结果表明,Ni、Ce、K的添加均提高了载氧体的合成气产率,10K-BF载氧体在水蒸气与生物质质量比(S/B)等于3,过氧系数α=0.20,反应温度800℃时,气化效果最好,合成气产率1.864 m³/(kg Biomass),氢气产率1.038 m³/(kg Biomass),碳转化率90.49%,积炭率1.33%,10次循环后仍有较高的气体产率及碳转化率。H₂-TPR表明10K-BF载氧体在300℃开始释氧,在生物质热解的初始阶段即可参与反应,有利于焦油的裂解;XRD表明10K-BF载氧体再生后可以恢复部分尖晶石结构。     

基于NiFe_2O_4载氧体的化学链蒸汽重整制氢实验研究

采用并流共沉淀法合成了具有尖晶石结构的NiFe_2O_4载氧体,研究了其在化学链蒸汽重整制氢过程中的氧化-还原反应性能。并利用X射线衍射(XRD)、拉曼光谱分析(Raman)、扫描电镜(SEM)、H_2程序升温还原(H_2-TPR)和热重分析对NiFe_2O_4载氧体进行表征和分析。结果表明,还原态载氧体在水蒸气气氛中可恢复部分晶格氧,热重实验进一步发现合成载氧体的反应活性显著高于商业载氧体,且其在约14 h的连续实验中展现了优异的循环反应性能。固定床实验表明,载氧体能显著促进生物质挥发分中大分子中间热解产物转化为小分子气体,特别是初次焦油的催化裂解,从而明显改善气体品质。由于Fe-Ni协同效应,经CO还原后的载氧体具有较强的制氢能力,每克还原态载氧体可产生232 mL纯氢。由于热力学限制使还原态载氧体在水蒸气气氛中只能恢复部分晶格氧至Ni、Fe3O4和Ni1-xFe2+xO4的三元混合物相。     

Co-Fe2O3[104]铁基载氧体优化体系作用下褐煤化学链燃烧特性

前期研究发现高弥勒指数晶面载氧体Fe₂O₃[104]具有高的化学链燃烧反应特性,且Co对煤及其热解中间产物具有催化气化和催化转化作用。通过正交实验优化制备Co-Fe₂O₃[104]/Al₂O₃载氧体体系结构,开展Co-Fe₂O₃[104]/Al₂O₃与褐煤的化学链燃烧,揭示载氧体与褐煤发生化学链燃烧的特性。结果表明:形貌控制制备的高弥勒指数晶面铁基载氧体Co-Fe₂O₃[104]/Al₂O₃(质量分数10%)促进了褐煤化学链燃烧过程中氧的迁移速率以及载氧体的还原程度,进而显著提高了载氧体与褐煤化学链燃烧的反应速率及反应效率。进一步通过CO多循环化学链燃烧反应、XRD和TEM表征了Co-Fe₂O₃[104]/Al₂O₃(10%)的可再生性及反应稳定性。     

Ni在WC合成过程中加速效应机理的研究

以W-C体系为研究出发点,高能球磨W、活性C和Ni的混合粉末,应用XRD、SEM、化学分析等手段,对球磨产物进行分析.结果发现,在机械合金化合成WC的过程中,Ni能有效的缩短反应时间,提高反应速率;原因是,在Ni的周围形成了以Ni为中心的微聚团,增大了W和C的接触机率和接触面积,缩短了扩散距离,从而缩短了反应时间.     

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.     

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。     

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.     

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.     

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.