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茶多酚的超临界萃取法研究 总被引:19,自引:0,他引:19
本文在温度为40℃,60℃和80℃,压力为12-22MPa,测定了茶多酚在超临界二氧化碳中的溶解度数据。然后在80℃及21MPa下,测定了干茶中茶多酚的萃取量与CO2累计用量的关系。 相似文献
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超临界CO2萃取蛋黄粉中甘油三酯和胆固醇的影响因素研究 总被引:3,自引:0,他引:3
以蛋黄粉为原料,研究用超临界CO2萃取技术脱除其中的甘油三酯和胆固醇的操作条件,得到了萃取压力、萃取时间CO2流量等因素对脱除率的影响。在24MPa、5h、50℃的条件下,某油三酯和胆固醇的脱除率可达80%以上。 相似文献
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超临界二氧化碳萃取器 总被引:2,自引:0,他引:2
介绍了超临界二氧化碳萃取及利用现有150L高压釜(压力20MPa)改造的超临界二氧化碳萃取器。据大量应用试验证明,经改造后的装置能满足操作压力低于20MPa的超临界二氧化碳萃取有机物的生产工艺需要,具有实际应用推广价值。 相似文献
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超临界CO2萃取小麦胚芽油研究 总被引:3,自引:2,他引:1
用超临界CO2萃取技术对小麦胚芽和成品麦胚进行了萃取研究。结果表明,最佳工艺条件为萃取压力25.0MPa,萃取温度32℃,用气楷7.61NM^3kg.h.所得的麦胚油品质优越,且其中的维生素E含量比溶剂法,压榨法所得麦油高。本研究为麦胚油的超临界萃取实现工业化生产提供设计参数。 相似文献
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超临界CO2萃取菊花油的实验研究 总被引:19,自引:0,他引:19
用超临界CO2 萃取技术对菊花油进行了萃取试验 ,考察了二氧化碳用量 ( 1 0~ 35kg/h)、萃取压力 ( 1 0~ 5 0MPa)、温度 ( 2 0~ 5 0℃ )等对萃取得率的影响 ,同时考虑设备投资对萃取过程的影响 ,得出了超临界二氧化碳萃取菊花油的最佳工艺条件 :萃取压力 30~ 35MPa,操作温度 2 0~ 4 0℃ ,CO2 的流量选择为 2 0~ 2 5kg/h。 相似文献
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重质油梯级分离新工艺的工程基础研究 总被引:2,自引:1,他引:1
利用自行开发的重质油超临界精密分离新方法对国内外多种重质油进行分析,结果表明重质油超临界精细分离窄馏分的重要物理和化学性质随溶解度(分离收率)的增加而变化,通过萃取可以使重质油中的重金属、沥青质等浓缩在萃取残渣中,而萃取馏分性质得到明显改善,据此提出了“重质油梯级分离”新工艺。为此在1 kg·h-1及10 kg·h-1连续式溶剂梯级分离实验装置上,以戊烷C5为溶剂,进行了大港减渣及辽河减渣的深度梯级分离脱除残渣的实验室研究和中试研究,考察了溶剂比、温度、压力等因素对脱残渣油收率和性质的影响规律。得到了超临界萃取的优化工艺参数:萃取温度 160~170℃,一、二段温差5~15℃;萃取压力4.0~5.0 MPa;溶剂比4.0~4.5(质量比)。确定了合适的超临界回收条件:温度200~220℃,压力4.0~4.5 MPa,可使溶剂和油得到有效的分离。根据萃取塔底所处的温度、压力条件及物料组成,创造性地提出了利用超临界条件下喷雾造粒技术,实现了硬沥青喷雾造粒并与萃取过程的耦合,并对硬沥青颗粒流化与输送性能进行了研究。研究结果为“重质油梯级分离”新工艺的工业放大奠定了工程基础。 相似文献
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M. S. J. Simmonds W. M. Blaney F. Delle Monache M. Marquina Mac-Quhae G. B. Marini Bettolo 《Journal of chemical ecology》1985,11(12):1593-1599
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. 相似文献
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Cheng-Le Zhao Shane Porzio Alan Smith Haiyan Ge H. T. Davis L. E. Scriven 《Journal of Coatings Technology and Research》2006,3(2):109-115
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. 相似文献
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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. 相似文献
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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. 相似文献
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中蓝晨光化工研究院有限公司《塑料工业》编辑部 《塑料工业》2009,37(3)
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. 相似文献
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中蓝晨光化工研究院《塑料工业》编辑部 《塑料工业》2007,35(3):1-25,67
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。 相似文献