超声辅助提取柚皮黄酮及其抗氧化性的研究

本论文采用超声波辅助提取柚皮中黄酮类化合物。首先考察超声波的提取时间、乙醇浓度、料液比、提取温度、提取功率五个因素对黄酮类化合物提取率的影响。单因素实验表明,提取时间和提取温度对黄酮类化合物提取率的影响不大,超声波辅助提取柚皮中黄酮的优化工艺条件为:料液比1∶15,乙醇的体积分数为60%,提取功率175 W,与传统工艺相比,超声法有较高提取率。Fenton法表明柚皮中的黄酮具有较强的抗氧化作用。     

红景天中黄酮类化合物的提取及抗氧化性研究

利用超声波辅助提取红景天中黄酮类化合物,采用单因素和正交实验研究了料液比、乙醇浓度、超声波功率、超声波时间、超声波温度对黄酮类化合物提取率的影响。结果表明,液料比为1∶35,乙醇的浓度为40%,超声波功率为280 W,超声波时间为40 min的条件下提取效果最佳。在最优化条件下测得总黄酮的提取率可达到17.08%,并测定黄酮类化合物对羟基自由基的消除能力。     

塔罗科血橙皮中黄酮类化合物的提取

本实验用单因素法和正交实验法探讨索氏回流提取法提取血橙皮中黄酮类化合物的提取条件。考察了乙醇体积分数、温度、时间及料液比对黄酮类化合物提取率的影响。实验结果表明:乙醇的体积分数为80%,温度为95℃,液料比为1∶40,时间为2.5 h的条件下提取效果最佳。测定总黄酮的提取率可达到1.515%。     

超声提取女贞子中黄酮类化合物的工艺研究

采用超声辅助乙醇提取女贞子中黄酮类化合物,考察乙醇浓度、超声功率、超声时间和料液比对提取率的影响。结果表明,最佳提取条件为:乙醇体积分数为50%,料液比1∶70(g/mL),600 W功率下提取20 min,并通过实验确定在此条件下黄酮类化合物的提取率达到13.61%。     

山药皮中黄酮的提取与抗氧化性的研究

以山药皮为原料,使用索氏提取法,选定乙醇体积分数、浸提时间、浸提温度和料液比为单因素条件,通过正交实验确定提取黄酮类化合物的最佳工艺条件,并在最佳条件下进行抗氧化性的研究。最佳工艺条件为:乙醇体积分数70%,浸提时间1.5 h,浸提温度60℃,料液比为1∶50,提取率为0.178%。通过实验可以看出黄酮类化合物具有较强的清除羟基自由基和DPPH自由基的能力。     

苦参总黄酮超声提取工艺优化研究

苦参中含有丰富的黄酮类化合物，为提高其提取率，优化苦参黄酮提取工艺，本实验以黄酮提取率作为评价指标，探究料液比、乙醇体积分数、超声波功率、温度及时间五个因素对黄酮提取率的影响，确定各因素的水平范围，采用三因素三水平正交试验确定最佳提取工艺条件为：料液比1∶36(g∶mL)、乙醇体积分数80%、提取时间20 min,苦参总黄酮提取率为1.05%。该提取方法操作简单，有良好的稳定性，可为苦参总黄酮的进一步研究与利用提供一定的实验依据。     

茅岩莓茶中黄酮类化合物提取工艺的分析研究

以茅岩莓茶为原料,采用不同体积分数的乙醇水溶液提取其中的黄酮类化合物,并用单因素和正交实验,依次考察乙醇体积分数、料液比、浸提温度以及浸提时间对黄酮提取率的影响,确定优化工艺参数。结果表明,当乙醇体积分数80%,料液比1∶20,浸提温度80℃和浸提时间4 h时,黄酮类化合物的提取率最高。     

超声波辅助提取八角莲黄酮类化合物的初步研究

采用单因素和正交试验对野生八角莲中黄酮类化合物的提取工艺进行研究。主要考察乙醇浓度、料液比、超声时间及超波功率等4个因素对提取率的影响,结果表明：超声波辅助提取的最佳工艺条件为：乙醇浓度50%、料液比1∶20、超声时间25 min、超声功率120 W,黄酮类化合物的提取率为7.183%。     

超声波强化提取荠菜中总生物碱的研究

采用超声波辅助提取法提取荠菜中总生物碱,考察了提取剂、料液比、提取时间、提取温度、超声波功率对生物碱提取率的影响.正交实验结果表明超声法的最佳提取条件为:乙醇体积分数为70%,料液比为1∶10,提取时间10 min,提取温度50℃,功率160 W.     

超声波辅助提取马兰叶中黄酮物质的条件研究

采用超声辅助乙醇提取马兰叶黄酮类化合物,最佳工艺条件为:乙醇体积分数80%,料液比1∶50(g/mL),提取温度30℃,提取时间40 min,颗粒度60目,提取3次。在此条件下,提取率达9.56%。该方法具有操作简单、提取时间短、提取率高,适于马兰叶总黄酮的提取。     

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。