木质纤维素可再生生物质资源预处理技术的研究进展

阐述了由木质纤维素可再生生物质资源制备生物燃料乙醇对我国可持续发展的重要意义.针对木质纤维素可再生生物质资源利用的关键技术,综述了国内外对木质纤维素可再生生物质资源预处理的研究进展,并重点介绍了物理法、化学法、物理-化学法和生物法预处理木质纤维素可再生生物质资源的技术.最后对木质纤维素可再生生物质资源预处理技术和应用前景进行了展望.     

用木质纤维素原料生产燃料乙醇预处理工艺研究进展

预处理是利用木质纤维素原料生产燃料乙醇过程中的关键步骤,其直接影响木质纤维素的水解效率和乙醇的生产成本。目前,对木质纤维素原料的预处理方法主要有物理法、化学法、物理化学法和生物法。文章对以上几种预处理方法的研究进行了简要综述,并对各种方法的优缺点进行了分析和讨论,最后对木质纤维素原料生产燃料乙醇预处理方法进行了展望。     

木质纤维原料蒸汽爆破-生物联合预处理及其生物脱毒研究进展

在木质纤维素类生物质结构中,木质素是生物质中纤维素与半纤维素进行生物降解的天然抗性屏障,预处理是打破木质纤维素抗性结构这一阻碍生物转化与利用瓶颈的最主要途径。本文分别概述了木质纤维素蒸汽爆破预处理技术与生物预处理技术的研究现状,介绍了蒸汽爆破-生物联合预处理的研究进展,分析了蒸汽爆破预处理过程中抑制物产生的机理和主要抑制物的种类,并提出了具有脱毒效果的蒸汽爆破-生物联合预处理技术,以及木质纤维素高效预处理技术研究发展方向。     

木质纤维素预处理技术研究现状与展望

木质纤维素是自然界中最丰富的可再生资源,可用于生产燃料乙醇、生物柴油等能源产品,也是制备化学品和造纸的主要原料。木质纤维素主要由纤维素、半纤维素和木质素组成,复杂的化学结构限制了其高效利用,故必须对其进行预处理,去除木质素、半纤维素等不可溶物质,从而使其更易被酶水解成可发酵的糖,进而提高木质纤维素的降解转化率。预处理技术可以改变木质纤维原料的内部结构和表面性质,为后续的酶解糖化创造良好条件。从物理、化学、生物、联合处理等4个方面全面综述了不同木质纤维素预处理技术的研究现状,总结了其预处理效果和优缺点,并展望了其未来的研究方向,旨在为木质纤维素生物质降解利用研究提供参考。     

蒸汽爆破预处理木质纤维素及其生物转化研究进展

木质纤维素生物资源可以用来生产乙醇,但其结构与化学成分阻碍了酶对纤维素的可及性,因此必须对原料进行预处理。在多种预处理方法中,蒸汽爆破法预处理因其成本低、能耗少、无污染而备受研究学者的青睐。通过对蒸汽爆破作用过程、机理和影响因素的研究分析,以及在生物转化方面的应用研究分析,更加显示出该法在此项领域广阔的前景,必将成为以木质纤维素为原料转化燃料乙醇的关键预处理技术之一。     

木质纤维素类原料生物炼制预处理技术的研究进展

木质纤维素原料结构的复杂性导致其不能实现高效转化,其预处理技术作为高效转化的关键步骤,已成为世界各个国家研究的热点。通过物理法、化学法、物理化学法、生物法等多种预处理手段,可使后续过程的转化效率提高。该文论述了国内外预处理研究近况,并对各种方法优劣点进行分析和讨论,在此基础上提出了一种崭新的预处理方法——"含氧类自由基氧化处理法",最后对木质纤维素原料预处理的前景进行了展望。     

木质纤维素乙醇原料预处理技术的研究进展

近十年来,随着石油价格的上涨以及化石燃料使用对全球变暖的影响,利用木质素纤维素制取燃料乙醇日益成为国内外研究的热点。木质纤维素制取乙醇的主要步骤包括:原料的预处理、纤维素的糖化、发酵、产品分离。木质纤维素的组成包括木质素、半纤维素和纤维素,其中木质素和半纤维素对纤维素的水解具有阻碍作用。因此,在木质纤维素制取乙醇的工艺过程中,原料的预处理是非常关键的步骤,影响整个木质纤维素乙醇的生产过程。文章回顾了木质纤维素原料主要的预处理技术的最新进展,并结合后续的水解与发酵工序,对各种预处理技术的优缺点进行了对比。     

木质纤维素新型预处理与顽抗特性

木质纤维素是地球上最丰富的可再生生物质资源,其中纤维类多糖的酶催化降解是木质纤维素生物精炼的关键环节之一。对木质纤维素进行预处理,破坏底物的顽抗特性,是实现木质纤维素高效酶解糖化的必要途径。为此,各国学者围绕预处理技术开发以及底物顽抗特性开展了大量研究,本文对近几年来在这两方面取得的最新成果进行了综述和分析。在预处理方面,重点介绍了组合预处理、低温预处理、绿色溶剂与电化学预处理4类新型预处理技术,并对预处理效果与技术优势进行了评价;在底物顽抗特性方面,综述了木质素、结晶度、酶可及度等不同顽抗特性对纤维素酶解的影响规律,重点总结了近年来顽抗特性研究方面的新方法、新认识与新理解。上述研究成果有助于了解当前木质纤维素预处理研究的导向以及明确制约纤维素酶解的关键因素,为设计和筛选适宜的预处理方式、深刻理解纤维素酶解机制提供基础和指导。     

木质纤维素预处理技术研究进展

介绍了木质纤维素的组成及结构特征,阐述了近年来的木质纤维素预处理技术,并对主要预处理技术作了评价.     

木质纤维素原料生产燃料酒精开发技术研究进展

在分析美国、日本、加拿大等国关于纤维素制取乙醇技术发展的基础上,对木质纤维素原料生产乙醇的预处理及水解为葡萄糖技术和纤维素原料发酵生产酒精生产技术、酒精废糟的处理利用进行了述评与讨论,对木质纤维素原料不同的预处理、水解和发酵方法进行了比较,展望了木质纤维素原料生产燃料酒精的前景.     

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。