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以普通硅酸盐水泥(P.O 42.5)为主要胶凝材料,发泡剂采用植物改性泡沫剂,以膨胀珍珠岩和聚苯颗粒作为轻质保温骨料,同时掺加适量玻璃纤维,运用物理发泡工艺制备了水泥基轻质发泡保温材料.通过电子扫描显微镜分别研究了水灰比、玻璃纤维和轻骨料(膨胀珍珠岩和聚苯颗粒)对水泥基发泡保温材料试样中孔结构及其分布的影响,同时探讨了孔结构及其分布与材料导热系数之间的相互关系.实验结果表明:水灰比、玻璃纤维、轻骨料(膨胀珍珠岩和聚苯颗粒)的加入量与水泥基发泡保温材料的孔结构及其分布状态密切相关. 相似文献
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试验以普通硅酸盐水泥(P.O42.5)为主要胶凝材料,采用膨胀珍珠岩和聚苯颗粒为轻质保温骨料,同时掺加适量玻璃纤维和防水剂;发泡剂采用植物改性泡沫剂,运用物理发泡工艺制备了水泥基轻质发泡保温材料.分别研究了膨胀珍珠岩、聚苯颗粒和防水剂掺量对水泥基轻质发泡保温材料性能的影响,确定了水泥基轻质发泡保温材料的最佳配合比.试验结果表明:玻璃纤维掺量占水泥质量1.5%,轻骨料总掺量为7%,膨胀珍珠岩与聚苯颗粒混合比例为1∶2,有机硅防水剂掺量为4%时,水泥基轻质发泡保温材料的各项性能指标良好,干密度较低、抗压强度较高且防水性能较好,其28 d干密度和抗压强度分别为298 kg/m3和1.43 MPa,体积吸水率为17.32%. 相似文献
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聚苯乙烯泡沫塑料颗粒(EPS颗粒)作为水泥基复合保温材料的超轻骨料,对水泥基复合保温材料力学性能、热工性能影响显著。以水泥为胶凝材料,EPS颗粒、混合材、泡沫剂和改性剂、水等为主要原料,采用物理发泡工艺制备干表观密度不大于120 kg/m3的超轻水泥基复合保温材料(UCIM)。通过设计不同体积掺量的EPS颗粒,分析EPS颗粒掺量对泡沫混凝土基体孔结构、超轻水泥基复合保温材料强度和热工性能的影响规律。结果表明,适宜掺量EPS颗粒可显著提高超轻水泥基复合保温材料抗压强度和抗拉强度,并确保超轻水泥基复合保温材料具有良好的热工性能,即通过EPS颗粒与泡沫混凝土基体的协同作用,协调力学性能和热工性能,制备出高性能超轻水泥基复合保温材料。 相似文献
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海绵型生态城市是目前我国正在大力推行的城市建设的目标,城市道路、绿地、排水管网等市政设施不但具有快渗快排功能,还应具有一定的水分保持功能.基于传统的泡沫混凝土,采用发泡剂与产气剂协同使用的方法制备了兼具透水和保水功能的泡沫混凝土.并系统研究了水灰比、发泡剂掺量、砂掺量和玻璃纤维掺量对材料透水性的影响规律,在此基础上研究了材料的水分保持性能与透水性能的相关性.结果表明:材料的透水性能随水灰比、发泡剂掺量、砂掺量的提高先增大后减小,并随着玻璃纤维掺量的提高逐渐减小.通过合理控制制备工艺,可获得具有较好透水率和保水性的泡沫混凝土材料,以满足海绵城市的建设的需求. 相似文献
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以聚苯乙烯颗粒为轻质集料,水泥和粉煤灰为胶凝材料,辅以多种外加剂,经化学发泡工艺制备水泥基墙体保温材料。通过掺加不同掺量的超高分子量聚乙烯纤维,研究了超高分子量聚乙烯纤维对水泥基墙体保温材料性能的影响,并采用扫描电子显微镜对试样的断口形貌进行分析,对超高分子量聚乙烯纤维的相关作用机理进行分析。研究结果表明:超高分子量聚乙烯纤维的最佳掺量为0.4%,此时水泥基轻质墙体保温材料的抗折强度、抗压强度、抗折软化系数分别为0.47 MPa、0.58 MPa、0.56,较空白试样分别提高了76.0%、61.1%、33.3%,在此条件下试样的密度和导热系数分别为218 kg/m3、0.056 W/(m.K)。 相似文献
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《广东化工》2015,(23)
以普通硅酸盐水泥、粉煤灰为主要原料,加入适量的外加剂,使用化学发泡的手段制备了密度小于300 kg/m~3的发泡水泥,研究了水温,减水剂用量和铝酸钠掺量对发泡水泥性能的影响。实验结果表明:在制备发泡水泥过程中,水温控制在40℃时双氧水的分解反应和水泥的水化硬化达到平衡,发泡效果最为理想;在发泡水泥中添加适量减水剂和铝酸钠有助于发泡水泥强度提高;以水泥∶粉煤灰∶发泡剂∶稳泡剂∶纤维=75.5∶20∶3.5∶0.8∶0.2,外掺0.6%减水剂和3%铝酸钠,水灰比0.51,水温40℃时,所制备的发泡水泥7 d抗压强度为0.63 MPa,导热系数为0.052 w/m·k。 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