超临界CO_2萃取大豆油的实验研究

采用超临界CO2 萃取技术进行了大豆油的萃取实验。在压力为 2 0～ 30MPa、温度为 30 8～ 32 3K的范围内 ,考察了萃取压力、萃取温度、流体流量和物料预处理方式等条件对出油率的影响。在本文实验范围内 ,大豆油的最佳萃取工艺条件为 :压力 30MPa ,温度 313K ,物料状态为约 0 .4mm厚的大豆片。流体流量只影响萃取速率 ,而不影响最终的出油率     

超临界CO2萃取生姜油实验研究与数值模拟

利用自建的超临界流体萃取实验装置,以CO2为萃取剂,考察了萃取压力、温度、流体流量及原料颗粒度等因素对生姜油累积萃取率的影响,由此确定了较佳的萃取工艺条件。基于萃取器微分单元质量守恒原理,建立了数学模型,并利用直线推动力近似理论拟合了总传质推动力及平衡吸收常数,对实验结果进行了数值模拟。     

超临界CO_2流体萃取烟叶中烟碱工艺研究

以烟叶为原料,研究了超临界二氧化碳流体萃取烟碱的工艺条件,以烟碱萃取得率为考察指标,在原料粒度40目,含水率25%,分离釜的压力4～5MPa,温度40℃的条件下,对萃取时间、萃取温度、萃取压力等因素进行了研究,确定了最佳工艺条件为:萃取时间为2h,萃取温度为50℃,萃取压力30MPa。经过验证烟碱萃取得率为2.92%,为工业化生产提供了实验数据。     

植物提取工艺

超临界CO2萃取大蒜油 福建卫生职业技术学院研究出超临界CO2萃取大蒜油的工艺。研究人员通过正交实验，确定了大蒜油的最佳提取工艺条件，即提取温度为35℃、提取压力为20mPa、CO2、每小时流量为30L、提取时间为3h是最佳的提取条件，其中，提取温度是关键的影响因素。在最佳提取条件下，大蒜油提取率达到0．35％，且杂质少，是有效的风味萃取方法。     

枸杞籽油超临界二氧化碳萃取方法的实验研究

建立了一套超临界流体萃取枸杞籽油实验流程．以CO2为萃取剂,考察了萃取压力、操作温度、CO2流量及原料颗粒度等因素对枸杞籽油萃取率的影响,确定了较佳的萃取工艺条件：压力30MPa,温度313-318K,枸杞籽颗粒40-50目,CO2流量0．3—0．4m^3/h时枸杞籽油萃取率最高,可达155％.     

超临界CO2流体萃取中华雪胆中齐墩果酸的研究

采用正交实验优化中华雪胆中齐墩果酸的萃取工艺条件,考察了萃取压力、温度、时间、CO2流量、夹带剂种类及用量对萃取率的影响,确定了超临界CO2流体萃取中华雪胆中齐墩果酸的最佳条件如下:萃取压力40 MPa,萃取温度55℃,无水乙醇为夹带剂,用量为5%,萃取时间为2 h,CO2流量为20kg·h1.与传统有机溶剂提取法相比,用超临界CO2流体萃取齐墩果酸,不仅方法简便、安全,而且提取的选择性与效率更高.     

超临界二氧化碳萃取枸杞籽油的实验研究与数值模拟

建立了一套超临界流体萃取枸杞籽油的实验流程。以二氧化碳为萃取剂,考察了萃取压力、操作温度、二氧化碳流量及原料颗粒度等因素对枸杞籽油萃取率的影响。确定了较佳的萃取工艺条件:压力30MPa,温度313～318K,枸杞籽颗粒40～50目,二氧化碳流量0.3～0.4m3/h时枸杞籽油萃取率最高,可达15.5%。基于萃取器微分单元和固态颗粒微分单元质量守恒原理,建立了微分方程,利用直线推动力近似理论拟合总传质推动力及平衡吸收常数,化简方程,对部分实验结果进行数值模拟。     

超临界流体CO_2提取虎杖中的有效成分

以大黄素为指标对虎杖中的有效成分进行超临界流体CO2萃取。用正交设计法考察了最优萃取条件。影响超临界流体萃取率的主要因素依次是:动态流量、温度、压力、时间;确定了大黄素的最佳萃取条件是:萃取压力25 MPa,萃取温度55℃,动态流量8 kg/h,萃取时间30 m in。超临界流体萃取大黄素的提取率达0.36%。     

用超临界CO2流体萃取大蒜油的研究

在超临界条件下,用二氧化作萃取剂从大蒜中萃取大蒜油的工艺条件,考察温度,压力,萃取剂用量对大蒜油收率的影响,结果表明,用超临界CO2从大蒜中萃取大蒜油的最佳工艺条件为温度35－40℃,压力15MPa,萃取剂用量5－6L/h.g.     

超声强化超临界流体萃取薏苡仁油和薏苡仁酯的影响因素及效果

考察了超声强化超临界流体萃取(USFE)薏苡仁中的薏苡仁油和薏苡仁酯的效果。以 CO2作为超临界流体分别研究了萃取过程中萃取温度、萃取压力、原料颗粒大小、超临界流体流量、超声参数、萃取时间等因素对萃取率的影响,并与超临界流体萃取(SFE)进行对比。结果表明,超声强化超临界流体萃取过程,最适宜的萃取温度为 40℃,比超临界流体萃取的最适宜的萃取温度降低了 5℃;最适宜的萃取压力为 20Mpa, 比超临界流体萃取的最适宜的萃取压力降低了 5Mpa;最佳萃取时间为 3.5h,比超临界流体萃取的最佳萃取时间缩短了 0.5h;萃取率提高约 10%左右。若萃取率相同时,流体流量可减少 0.5L·h-1 ,原料粒径的要求可放宽。     

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。