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硬硅钙石水热合成的形成历程及硝酸锶对它的影响 总被引:7,自引:2,他引:5
利用XRD,SEM,TEM等方法对动态水热法合成硬硅钙石的形成历程进行了研究,由C-S-H凝胶不能在高于200℃温度下稳定存在,使硬硅钙石在180℃和220℃时的形成历程不同,配料中加入硝酸锶,提高料浆的离子强度,产生原盐效应,降低了C-S-H凝胶的生成速率,延缓了硬硅钙石的形成,硬硅钙石合成过程中的料浆中固体粒子的ζ电位是不断变化的,加入硝酸锶,可以降低料浆固体粒子ζ电位的绝对值,有利于硬硅钙石纤维状晶体以及团聚体的长大。 相似文献
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水热合成硅酸钙微孔球形颗粒 总被引:4,自引:2,他引:4
动态水热合成生成的硅酸钙微孔球形颗粒的空隙率可高达90%以上,颗粒由无数纤维状硬硅钙石晶体构成.讨论了合成工艺参数对形成球形颗粒的影响.反应物中SiO2 和CaO的比例需保持1∶1,否则反应最终产物中可能出现其它硅酸钙矿物.搅拌对形成球形颗粒起着决定性作用,在搅拌作用下C-S-H凝胶表面受到切向剪切力矩的作用,片状的凝胶被卷成为球形颗粒.在水热合成过程中加入矿化剂能够降低凝胶粒子ζ的绝对值,促进C-S-H凝胶形成大的团聚体,矿化剂的存在提高了由C-S-H凝胶团聚生成硬硅钙石的温度,从而保证C-S-H凝胶团聚有充足的时间形成大的球形团聚体. 相似文献
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用稻壳灰水热合成硬硅钙石的研究 总被引:7,自引:0,他引:7
研究了用稻壳灰作硅质材料水热合成硬硅钙石。结果表明,在合理选择钙硅比、水固比、搅拌时间,反应时间、反应温度等水热合成条件的情况下,稻壳灰中的SiO2能够与Ca(OH)2反应生成硬硅钙石晶体,并且这种纤维状的晶体还能相互交织成二次球形粒子。 相似文献
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蒸压DSP浆体的反应产物研究 总被引:1,自引:0,他引:1
将以白水泥和硅灰制成的DSP水泥浆体于120℃、183℃、240℃下蒸压。用X射线粉末衍射法、固体核磁共振和扫描电子显微镜检验反应产物。研究了C/S、蒸压温度、蒸压时间对反应的影响。在较低温度下,主要水化产物为结晶差的C-S-H凝胶,随蒸压温度升高,可检测到硬硅钙石、托勃莫来石、自钙沸石、含水斜方硅钙石和含水8CaO·5SiO_1等晶体。初始混合物的C/S在1.3和1.1之间,水化产物有明显变化。实验表明,~(29)Si核磁共振是研究硅酸盐聚合度的有效方法。 相似文献
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《耐火材料》2017,(5)
为提高硬硅钙石制品的耐压强度,首先将预处理后的石英粉、消化后的Ca O、添加剂、去离子水(按水、固质量比为30量取)置于磁力搅拌高压釜中,在220℃分别保温0、1、3和6 h后得到相应产物,探究硬硅钙石的合成;然后,在制得的硬硅钙石粉体中分别加入0、5%、10%、15%和20%(w)的预处理陶瓷短纤维,经压滤成型和烘干后,于1 000℃保温2 h烧成,研究陶瓷纤维加入量对硬硅钙石试样烧成前后耐压强度的影响。结果表明:在硬硅钙石的合成过程中,首先生成C-S-H凝胶,然后C-S-H凝胶转化形成托贝莫来石,最终托贝莫来石完全反应生成了硬硅钙石;陶瓷纤维的引入提高了硬硅钙石试样烧成前后的耐压强度,当加入15%(w)陶瓷纤维时,耐压强度最大;1 000℃烧成前后试样中的物相分别是硬硅钙石相和硅酸钙相,烧成后试样的耐压强度比生坯试样的大。 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