微波辅助法提取老鹳草中总黄酮的工艺研究

采用微波辅助法提取老鹳草中总黄酮。首先通过单因素实验,考查提取液浓度、液料比、提取时间和微波功率对提取率的影响。再采用正交实验的方法对提取工艺进行优化,得到最优工艺条件:乙醇浓度70.0%,液料比20.0 m L/g,提取时间120 s,微波功率385 W。实验表明总黄酮得率为1.738%。     

微波法分批次提取柑橘皮中果胶的工艺研究

利用浓度梯度能提高浸出效率,分批次采用微波加热提取柑橘皮果胶。通过单因素实验,研究了不同酸、料液比、微波功率、微波时间、p H值等反应条件对产率的影响。结果表明:果胶的最佳提取条件为:盐酸为萃取剂,料液比为1∶15,微波功率700 W,微波辐射时间为5 min,提取液p H值为1.8,果胶得率22.9%。     

微波法提取毛泡桐花总黄酮的工艺研究

通过单因素实验和正交实验,研究乙醇浓度、料液比、微波作用时间、微波功率对毛泡桐花总黄酮提取得率的影响。单因素实验结果表明:微波提取毛泡桐花总黄酮的最佳工艺条件为,料液比1∶15,微波功率500 W,微波作用时间150 s,乙醇浓度70%,此条件下总黄酮得率为7.71%。正交实验结果表明:影响因素的显著性顺序为乙醇浓度>微波功率>料液比>微波作用时间。最佳工艺条件为A2B3C2D3,即料液比1∶20,微波功率500 W,微波作用时间150 s,乙醇浓度70%。     

荔枝核黄酮类化合物的提取工艺研究

采用回流、热浸提、微波提取等工艺提取荔枝核黄酮类化合物,采用正交实验考察了提取溶剂浓度、提取时间、微波功率、提取温度、料液比等因素对提取率的影响,优选出不同工艺的提取条件。回流提取工艺的优化条件是:50%乙醇溶液,提取温度80℃,提取时间1h,料液比1∶10,提取3次,总黄酮得率为6.76%。热浸提工艺的优化条件是:50%乙醇溶液,提取温度70℃,提取时间1.5h,料液比1∶12,提取2次,总黄酮得率达到6.37%。微波提取工艺的优化条件是:60%乙醇溶液,微波功率700W,提取时间2.5h,料液比1∶25,总黄酮得率达到6.86%。     

微波辅助提取万寿菊花总黄酮的工艺研究

以万寿菊花粉末为原料,采用单因素和正交实验考察了微波辅助提取的微波功率、微波辐射时间、乙醇浓度和料液比对万寿菊花总黄酮得率的影响。结果表明,微波辅助提取万寿菊花总黄酮的最佳工艺条件为:微波功率480 W,微波辐射时间120 s,乙醇浓度70%,料液比1∶40,提取次数2次。在此最佳工艺条件下,万寿菊花总黄酮得率达到40.45 mg/g。     

超声微波协同萃取维药雪菊中总黄酮工艺研究

研究及优化了超声微波协同萃取维药雪菊中总黄酮的工艺。以雪菊中总黄酮含量为指标,通过单因素实验确定影响总黄酮主要因素,再通过正交试验确定影响总黄酮提取的主要因素的最佳水平。结果表明,最佳提取条件为:提取时间为60 min,超声-微波提取功率为100 W,料液比为1∶20(W/V),提取液为50%乙醇,含量为20.33%。该试验筛选出超声微波协同萃取法提取雪菊中总黄酮的最佳条件,该法具有工艺简单、快速、高效、环保等优点。     

微波提取苹果渣中总黄酮的工艺研究

采用微波辐射技术,以乙醇提取苹果渣中黄酮类化合物。考察了乙醇浓度、微波功率、处理时间、料液比和浸泡时间对总黄酮提取率的影响。结果表明,最佳工艺条件为:70%乙醇,微波萃取2 min,微波功率为350 W,料液比1∶30(g/mL),总黄酮1次提取率0.683 7%。     

微波法提取款冬花总黄酮的研究

研究了微波法提取款冬花总黄酮的工艺。通过单因素实验和正交实验确定微波法提取款冬花总黄酮的最佳工艺条件为:微波功率400 W、提取溶剂60%乙醇、液料比20∶1(mL∶g)、提取时间9 min,在此条件下总黄酮提取率为9.7%。与传统提取方法相比,微波提取法具有短时高效的优点。     

回流法提取银杏叶总黄酮的研究

研究了乙醇回流法提取银杏叶总黄酮的工艺条件。通过单因素实验考察料液比、乙醇体积分数、提取时间、提取温度对银杏叶总黄酮提取率的影响,通过正交实验确定优化的提取工艺条件为:料液比1∶45(g∶mL)、乙醇体积分数50%、提取时间2.0h、提取温度70℃,在此条件下,银杏叶总黄酮提取率为0.918%。以优化的工艺条件为基础进一步运用微波辅助提取银杏叶总黄酮,发现在微波功率为640W时,采用间歇式提取,提取时间为15×10s,总黄酮提取率达到0.91%,接近传统方法提取3h的提取率。     

醉鱼草总黄酮的提取及抗氧化活性研究

以醉鱼草为研究对象,选择料液比、超声功率、微波功率和提取时间进行单因素实验,以单因素试验结果为参考,利用响应面试验设计对超声波-微波联合提取醉鱼草中总黄酮的工艺进行筛选优化,并对DPPH自由基及羟自由基进行体外抗氧化活性研究.修正最佳工艺条件为:料液比1:48(g/mL),超声功率389 W,微波功率446 W,提取时...     

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。