双颗粒提升管中细颗粒的混合行为研究(Ⅰ)──轴向混合行为

利用磷光颗粒示踪技术对双颗粒提升管中细颗粒的轴向混合行为进行了研究测得反映细颗粒轴向扩散的停留时间分布曲线呈双峰分布，这表明细颗粒存在两种类型的扩散形式：弥散颗粒扩散和颗粒团扩散本文提出的一维两组分扩散模型可较好地描述停留时间分布曲线的双峰分布.实验结果表明细颗粒的两种轴向混合行为有较大的差别，而总包Peclet数几乎不随操作条件及床内粗细颗粒比例变化     

流动方向对循环流化床中颗粒混合行为的影响

对循环流化床提升管及下行床两种不同气固流动方式对颗粒混合行为的影响进行了较为深入的对比分析，发现在影响循环流化床颗粒混合的众多因素（如操作条件、床层直径、颗粒性质及床层内构件等）中，气固流动方向是影响颗粒轴向混合的最主要因素．当气固流动为顺重力场时（下行床），颗粒的轴向混合很小，流型接近平推流；当气固流动为逆重力场的提升管时，轴向颗粒混合将成倍增大，颗粒流动远离平推流流动．分析表明，下行床中颗粒混合仅为单一的弥散颗粒扩散，而提升管中则存在着两种颗粒混合机制：弥散颗粒扩散及颗粒团扩散．弥散颗粒的扩散基本以平推流的形式通过循环流化床，提升管中大量的颗粒轴向返混归因于颗粒团的严重返混并由此形成了提升管中颗粒停留时间的双峰分布．     

双颗粒提升管中细颗粒的混合行为研究(Ⅰ)──轴向混合行为

利用磷光颗粒示踪技术对双颗粒提升管中细颗粒的轴向混合行为进行了研究测得反映细颗粒轴向扩散的停留时间分布曲线呈双峰分布,这表明细颗粒存在两种类型的扩散形式：弥散颗粒扩散和颗粒团扩散本文提出的一维两组分扩散模型可较好地描述停留时间分布曲线的双峰分布.实验结果表明细颗粒的两种轴向混合行为有较大的差别,而总包Peclet数几乎不随操作条件及床内粗细颗粒比例变化     

二维三相循环流化床液体停留时间分布的研究

用脉冲示踪法对二维三相循环流化床液体停留时间分布(RTD)进行了测定。在气速2～3m／s,液体循环量0～0．35m^3／h,固体循环量1．5～1．75g／s的范围内测得的液体停留时间分布曲线均有明显的3峰分布。其中前两峰分布是由于提升管中颗粒与液体之间和液体与气体之间共同作用改变了液体轴向速度分散程度的结果。第三个峰的分布是由于液体进入循环仓循环后在出口处检测的RTD曲线,并且提出一维两组分扩散物理叠加模型,模型的预测结果与实验获锝的RTD曲线平均误差小于5％,可较好地描述提升管中液体停留时间分布曲线。     

浆液循环锥形鼓泡塔反应器的相含率研究

在浆液循环条件下，考察了以空气、水和石英砂为三相体系的锥形鼓泡塔反应器（Φ顶２００ｍｍ，Φ底１００ｍ，高３０００ｍｍ）中的相含率及固体颗粒浓度轴向分布。使用压降法和颗粒同步取样方法测量了不同表现气速（０￣０．１２５ｍ／ｓ），表现浆液循环速（０￣０．１５７ｍ／ｓ）以及固体颗粒浓度０￣１００ｋｇ／ｍ＾３下相含率分布，并用园柱床的一维沉降－扩散模型近似地描述了固体颗粒辆向浓度分布的规律。在此基础上，本文     

多段分级转化流化床提升管速度场的研究

针对流化床煤气化过程中需要长气固接触时间和高固体浓度,开发了耦合灰熔聚流化床和提升管的多段分级转化流化床。为了研究多段分级转化流化床提升管中局部颗粒速度的径向、轴向分布,在不同的操作条件下,采用PV-6型颗粒速度测量仪在冷态实验装置中系统测定提升管内局部颗粒速度。实验结果表明:提升管中任何径向、轴向位置的颗粒速度随着操作气速的增大而增大,随循环量的增加而减小。操作条件对中心区颗粒速度变化的影响明显高于边壁区。颗粒的加速首先发生在提升管中心区域,然后向边壁区域扩展。颗粒速度径向分布的不均匀性沿轴向逐渐增大,并且受操作气速影响比较大。     

双颗粒提升管中细颗粒的混合行为研究(Ⅱ)──弥散颗粒的轴径向混合行为

利用磷光颗粒示踪技术，使用点源示踪的方法在不同的径向位置测得反映颗粒径向扩散行为的停留时间分布曲线，并对弥散细颗粒的径向混合行为进行了分析．提出二维扩散模型描述所测量的停留时间分布曲线特征．实验发现弥散细颗粒的径向扩散Peclet数随粗颗粒加入量的增加而增加，随细颗粒浓度的增大而增大，而几乎不随气速变化．给出了一个与实验数据吻合较好并可适用于单颗粒提升管的关联式．     

提升管-下行床耦合反应器内颗粒混合行为

引　言循环流化床中气固两相的流动有两种不同的方式 :提升管中为气固并流上行的逆重力场运动 ,下行床中为气固并流下行的顺重力场运动 .其差异表现为提升管内颗粒浓度、速度以及气体速度在径向上严重的不均匀 ,颗粒浓度概率密度分布以及速度的瞬时信号都表明了颗粒团 -空穴两相结构的存在[1] ,一些研究[2 ,3] 还发现提升管中颗粒的停留时间分布 (ＲＴＤ)曲线存在较大的拖尾甚至出现双峰 ,研究者认为提升管内存在弥散颗粒和颗粒团两种不同的混合机理 ;下行床则比提升管大大改善 ,气固速度、颗粒浓度沿径向分布要均匀得多 ,颗粒的ＲＴＤ曲线…     

耦合流化床提升管流动结构及边壁层厚度的研究

在射流流化床与提升管耦合的多段分级转化流化床冷态实验装置上,采用压力传感器和PV-6型颗粒速度测量仪,对提升管流动结构和边壁层厚度进行了系统研究。结果表明,一定的操作气速下,固体循环量增加使提升管中气固流动状态从稀相气力输送过渡到快速流态化区域。当提升管处于快速流态化区域时,一定固体循环量下,表观气速增加使提升管轴向各个位置的边壁层厚度减小;一定气速下,固体循环量增加使提升管各个截面的边壁层厚度增加,且低气速时提升管各个截面的边壁层厚度随固体循环量增加的程度明显高于高气速时。拟合得到了边壁层厚度与截面平均固体浓度的关系式,较好地预测了快速流态化区域内边壁层厚度随截面平均固体浓度的变化关系,该表达式的计算值和实验值吻合较好。     

双颗粒提升管中细颗粒的混合行为研究(Ⅱ)──弥散颗粒的轴径向混合行为

利用磷光颗粒示踪技术,使用点源示踪的方法在不同的径向位置测得反映颗粒径向扩散行为的停留时间分布曲线,并对弥散细颗粒的径向混合行为进行了分析．提出二维扩散模型描述所测量的停留时间分布曲线特征．实验发现弥散细颗粒的径向扩散Peclet数随粗颗粒加入量的增加而增加,随细颗粒浓度的增大而增大,而几乎不随气速变化．给出了一个与实验数据吻合较好并可适用于单颗粒提升管的关联式．     

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.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008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、不饱和聚酯树脂、环氧树脂)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.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006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生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。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（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。