草珊瑚总黄酮的超声提取工艺研究

研究了超声法提取草珊瑚总黄酮的工艺.影响草珊瑚总黄酮提取率的主要因素是乙醇体积分数,其次是提取次数,提取时间和液料比对提取率影响不显著.正交实验确定草珊瑚总黄酮的最佳超声提取条件是:40%乙醇,液料比10∶1,提取时间40 min,提取3次.此条件下总黄酮得率为8.53%.超声提取法具有短时高效的优点,适合于草珊瑚总黄酮的提取.     

微波提取苦瓜总黄酮的工艺研究

以苦瓜果实为原料,以总黄酮提取率为评价指标,通过单因素实验考察了微波功率、液固比、乙醇体积分数、苦瓜粉末粒度等对总黄酮提取率的影响;在此基础上,通过正交实验确定最佳提取工艺条件为：微波功率500 W、液固比11∶1（mL ∶ g）、乙醇体积分数60％、苦瓜粉末粒度80目,在此条件下总黄酮提取率为15.576 mg·g-1.     

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。     

响应面法优化野菊花总黄酮的微波提取工艺

以总黄酮提取率为评价指标,采用单因素实验和响应面法实验优化野菊花总黄酮的微波提取工艺。确定最佳提取工艺为:乙醇体积分数80%、液料比30∶1(mL∶g)、微波功率300W、微波提取时间16min,在此条件下,总黄酮提取率为0.47%。该提取工艺设计合理,为进一步研究野菊花总黄酮提供了科学依据。     

微波法提取黑木耳黄酮类化合物的研究

采用微波法提取了黑木耳中黄酮类化合物,考察了微波辐射功率、微波辐射时间、固液比和乙醇体积分数对提取率的影响.通过单因素实验和正交实验确定黑木耳中黄酮类化合物的最佳微波法提取条件为:微波辐射功率560W、微波辐射时间50 s、固液比1∶9(g∶ mL)、乙醇体积分数90％,此时提取率为0.665％.     

正交实验优化长春碱微波辅助提取工艺

采用微波辅助提取法提取长春花中的长春碱,通过微波提取时间、乙醇体积分数、微波功率、固液质量体积比(g/mL)、浸泡时间5个因素对长春碱提取率的影响进行了正交实验,确定微波提取最佳工艺条件为A2B1C1D4E3,即提取时间2 m in、体积分数为80%的乙醇、微波功率为低火、固液质量体积比1∶20(g/mL)、浸泡时间为1 h。微波提取长春花叶片中长春碱的提取率为0.011 427%,是回流提取的1.24倍,是超声提取的1.16倍。结果表明:微波提取长春花中长春碱具有提取时间短、速度快、提取率高等特点。     

金银花中绿原酸的微波辅助提取工艺研究

采用微波辅助法提取金银花中的绿原酸,研究了乙醇体积分数、料液比、微波功率和微波处理时间对绿原酸提取率的影响.通过单因素实验和正交实验确定最佳提取工艺为:乙醇体积分数60％、料液比1∶ 10(g∶ mL)、微波功率300 W、微波处理时间9 min,在此条件下,绿原酸提取率达3.779％.     

莲子心中生物碱的提取工艺研究

以莲子心为原料,用微波辅助醇提水沉法提取莲子心中生物碱。在单因素实验基础上,通过正交实验优化了提取工艺,结果表明,各因素对总生物碱提取率影响的大小顺序为:微波功率>微波时间>料液比>乙醇体积分数。最佳提取工艺条件为:微波功率400W、微波时间5min、料液比1∶30(g∶mL)、乙醇体积分数65%,在此条件下莲子心总生物碱的提取率达2.9873%。     

微波辅助提取花生壳总黄酮的工艺优化

以花生壳为原料,采用微波辅助提取花生壳中的总黄酮。探讨了乙醇体积分数、微波时间、料液比和提取温度对总黄酮提取的影响。在单因素的基础上,通过正交试验优化工艺。结果表明,最佳提取工艺条件为:微波时间2min,提取温度50℃,乙醇体积分数70%,料液比1∶25(g/m L),在此工艺条件下,花生壳总黄酮的提取率为8.9436%。     

微波辅助提取竹叶黄酮的研究

用微波辐射技术辅助乙醇提取竹叶总黄酮的结果表明,微波辅助萃取的最佳工艺条件为:固液比为1∶25(w/w),溶剂乙醇的体积分数为60%,微波功率为600 W,辐射时间为6 min。在此条件下,竹叶中的总黄酮提取率可达2.93%。     

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。