基于加热均匀性的微波干燥研究进展

微波干燥通过电磁场辐射物体而在其内部产生热量,促进物体内部水分向外部迁移,是一种先进的干燥技术。但是,微波干燥存在加热不均匀的问题。本文针对该问题,分析了导致微波加热/干燥不均匀的影响因素,综述了通过提高微波干燥室内电磁场分布均匀性及改变被处理物料位置,以改进微波加热均匀性的可行措施,最后指出进一步实现微波均匀干燥的研究发展趋势。     

水合硫酸铝的微波脱水研究

研究了水合硫酸铝微波脱水新工艺，与常规热风干燥工艺相比较，微波干燥10min的脱水效果明显优于105℃热风干燥120min的结果，与250℃热风干燥60min结果相当。同时测定了水合硫酸铝在微波场中的升温性能。     

连续(通带)式微波干燥炉

微波干燥是一种节能、环保、快速而又温和的干燥方式 ,在一定条件下甚至还能增加产品强度 ,因此为世界各国所重视 ,在未来工业生产中的作用将会越来越大。前不久德国某公司推出了一种专利产品———ＭＢＤＴ系列微波干燥炉。这种微波干燥炉的特点是 :(1)采用组合式构造 ,在任何时候都可以很方便地组装起来 ;(2 )它的微波发生器围绕其圆筒形炉膛的轴线成螺旋状分布 ,以便获得更加均匀的微波场 ;(3)在安装传送带的底盘上还安装有次级微波发生器 ,这使得微波场更加集中 ;(4 )在炉膛两端的出、入口部位镶有一种特殊的微波吸收材料 ,以便使其微波…     

WDZ型智能化微波真空连续干燥机

该干燥机在采用微波和真空技术的同时,还运用了动态结构和干燥过程动态显示手段,物料在干燥器内作直线连续运动,在微波场中和真空环境下完成干燥的全过程。在干燥过程中,物料接收到的微波总能基本一致,物料的干燥程度也基本相同,物料干燥均匀,并实现了连续干燥作业,从而大大克服了间歇干燥产量低、操作不便等弊病。该设备由于还同时采用了真空干燥技术,其汽化温度大大降低,物料中的湿分能迅速变成蒸汽,从而使物料在低温下就能进行干燥,特别适用于低融点、热敏性物料的干燥。将其应用于黏稠、胶状、极难干燥的浸膏类物料场合,取得了非常满意的效果。     

胡萝卜微波真空干燥试验研究

以胡萝卜为原料，采用均匀设计对微波真空干燥的微波功率、干燥温度及料层厚度进行试验研究，分析各试验条件下的水分含量及胡萝卜素含量，得到了干燥曲线和胡萝卜素保有量曲线，得出了胡萝卜失水量、胡萝卜素含量与各因素之间的回归方程，可用于描述胡萝卜的微波真空干燥特性。     

农产品微波干燥均匀性研究

微波干燥技术具有脱水速度快、热效率高、易于控制等特点,并且能很好地保持物料中的营养成分,兼具杀菌作用。但在农产品微波干燥过程中,干燥均匀性一直是难以解决的瓶颈问题。微波对于农产品加热具有选择性,过度加热,易出现物料边缘或尖角部分焦化、产品表面硬化和内部糊化等现象。本文以解决农产品微波干燥均匀性的问题为切入点,对目前国内外相关研究进行了较为全面的分析和归纳,为微波技术在农产品干燥中的应用提供参考。     

微波干燥卫生陶瓷的研究与设备开发

本文利用微波干燥法进行卫生陶瓷坯体干燥试验,探究微波可以实现对卫生陶瓷快速干燥的原因。在此基础上,对围绕着微波设备大型化、连续化中面临的关键技术及微波干燥电耗相对较高等技术进行攻关,开发了卫生陶瓷微波干燥辊道窑,并在实际工厂使用。结果表明:微波干燥过程实现了沿坯体纵向与沿坯体局部区域横向的均匀干燥及微波干燥能显著提高干燥的内扩散速率,最终实现对卫生陶瓷的快速干燥;采用微波、热风耦合加热技术能显著降低微波干燥电耗;开发的卫生陶瓷微波干燥辊道窑,可极大缩短干燥周期,降低场地占地面积,提高干燥合格率。     

多层带式干燥机风速场的CFD模拟及检验

多层带式干燥机箱内风速分布不均匀是导致干燥效率低、干燥不均匀的主要原因。对多层带式干燥机风速场进行了实验研究，建立了多层带式干燥机箱的CFD理论模型，对其风速场进行了数值模拟，并与实验测试结果进行对比，认为用CFD方法模拟多层带式干燥机箱内风速场是可行的。     

涂装漆层微波干燥工艺实验及开发应用研究

微波干燥是近年发展起来的新兴干燥技术,干燥均匀,速度快,消耗时间少。微波干燥漆层的实验结果表明:对塑料零件的漆层,微波干燥在除水方面效果良好,但漆膜固化还有待进一步研究。     

微波技术在蚕茧干燥中的应用研究

微波干燥是近年来被广泛应用的一项新技术。在阐述微波干燥原理、特点及微波干燥蚕茧机理的基础上，就近年来微波技术在蚕茧干燥方面的应用研究及其进展作了综述，分析了微波干燥蚕茧应用研究中存在的问题，探讨了微波技术在蚕茧干燥方面的应用前景。     

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。