共查询到20条相似文献,搜索用时 78 毫秒
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镁铝尖晶石作为一种有前途的绿色环保型无机功能材料,凭借其优良的性能和低廉的价格等特点而受到广泛关注。在总结镁铝尖晶石基本结构和特点的基础上,对镁铝尖晶石粉体的主要制备方法及其在发光材料领域的研究进展进行了综述。相比于传统固相法和燃烧法,液相法中的环保型水热合成技术在制备特殊形貌的纳米级镁铝尖晶石功能粉体方面具有优势。此外,分析了稀土、过渡元素离子掺杂镁铝尖晶石(MgAl2O4)发光材料的荧光性能特点,指出稀土掺杂镁铝尖晶石的上转换发光尚待深入研究,以适应其在生物医学中的应用;过渡元素离子掺杂镁铝尖晶石发光材料,则凭借其鲜艳的色彩表现有望作为一种有前途的固体激光材料。 相似文献
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氢氧化镁作为一种新型无机阻燃材料,具有热稳定性好、分解温度高等特点,且受热分解后无腐蚀性和有毒物质产生,其应用前景较为广阔。介绍了氢氧化镁阻燃剂的阻燃机理及特点。重点阐述了近年来氢氧化镁阻燃剂的制备方法,并对其存在的问题和发展方向进行了讨论。氢氧化镁阻燃剂的制备方法主要有固相法、气相法和液相法。固相法制备阻燃型氢氧化镁较为简单,但不易控制产品的粒径、形貌和分散性能。气相法制备氢氧化镁阻燃剂,采用氨气作为沉淀剂,制备工艺不易控制,而且氨气易于扩散污染环境。液相法制备氢氧化镁是最常用的方法,通过控制原料浓度、反应温度等条件,可以获得形貌和尺寸较好的氢氧化镁,也可扩大生产。 相似文献
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以磷酸亚铁锂为正极材料的锂离子电池以其高安全、高环保、低价格、长寿命、大容量等特点,将逐步取代现有铅酸电池市场,成为未来动力锂离子电池研究的热点材料。简述了几种常规合成磷酸亚铁锂方法的同时,较系统地介绍了磷酸亚铁锂材料在液相共沉淀制备方法中的研究进展,包括全液相共沉淀法和半液相共沉淀法。指出全液相法合成工艺比较简单、工艺路线较短,但是由于溶液体系中各组分沉淀速度存在差异,因而可能会导致组成的偏离和均匀性的丧失;半液相法虽然增加了工艺流程,但是可以通过控制pH、滴加速度等控制磷铁复合盐的形成,使产品呈球状,进而有助于提高磷酸亚铁锂的振实密度。 相似文献
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《合成纤维工业》2017,(5):51-56
介绍了多面体低聚倍半硅氧烷(POSS)的分类、结构和性能,POSS是基于化学键合作用而形成的一种分子水平上的纳米有机/无机杂化体,具有规整的立体结构、纳米尺度、优良的相容性和修饰性,其独特的纳米笼形结构使之成为分子结构设计和材料改性的最佳选择。综述了POSS的合成方法及研究进展,如三官能度硅烷或四官能度硅烷在酸、碱或有机盐催化下通过水解缩合反应合成POSS;以POSS为母体,通过封角闭环法和官能团转化衍生法合成POSS;点击化学法制备POSS等。比较了各种方法的优点和存在的问题,指出目前国内POSS的研究重点是合成带有高活性的POSS单体,改进合成路线及工艺,为其工艺化提供技术支持。 相似文献
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《化工进展》2017,(Z1)
四氧化三铁是一种重要的功能材料,因其具有优异的磁性能和较高的化学稳定性而被广泛应用于水体净化、磁流体和靶向药物等领域。四氧化三铁的合成方法主要有共沉淀法、热分解法、微乳液法及溶剂热法。其中,溶剂热法因流程简单、所得产物形貌多样、规整度高而得到广泛关注。该法所用的溶剂、矿化剂、表面活性剂等对Fe_3O_4纳米粒子的形貌及性能有较大影响。基于此,本文对溶剂热法制备Fe_3O_4纳米粒子进行了回顾,阐述了溶剂热法合成空心Fe_3O_4纳米粒子的机理。结果表明:在合成过程中,溶剂不仅作为还原剂,还提供合成所需的液相环境;矿化剂可促使铁前体的溶解,从而保证合成反应顺利进行;表面活性剂可与Fe_3O_4晶面作用,其种类和浓度不同,作用的晶面不同,进而诱导Fe_3O_4生长为不同形貌的纳米粒子。最后,本文对溶剂热法合成Fe_3O_4纳米粒子今后的发展趋势进行了展望,指出在空心Fe_3O_4纳米粒子的基础上,通过选择黏度较大的溶剂和表面活性剂合成多层壳状Fe_3O_4纳米粒子是研究者努力的方向。 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