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1.
王培铭  李好新  吴建国 《硅酸盐学报》2007,35(10):1353-1358
通过非等温差示扫描量热分析和扫描电子显微镜,结合CuO-CaO系统相图,研究CuO在CaCO3和SiO2混合物中的掺量(质量分数)对硅酸三钙(C3S)矿物形成机理的影响.用X射线衍射分析了最终烧制试样的多晶型组成.结果表明:在C3S矿物形成的过程中,少量CuO的加入并没有显著地影响到CaCO3分解表观活化能.但是CuO的加入为C3S矿物的形成提供了液相,增加了液相量,液相的主要成分约80%为CuO.CuO的加入对C3S矿物的晶型产生了显著的影响.当试样中掺入0,1.0%,1.5%,2.0%CuO时,C3S多相体为T型;当试样中掺入0.5%CuO时,C3S多相体为R型;当试样中掺入3%CuO时,C3S多相体为M型.  相似文献   

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采用非等温热重分析技术对比研究了Na2CO3,BaCO3和CaCO3对高灰分煤粉(灰分〉44%)燃烧反应动力学参数的影响。非等温热重分析以20℃/min的升温速率从室温升到1000℃,动力学参数采用Coats—Redfern方程进行计算.结果表明:与空白煤样对比,掺有碳酸盐的煤样着火温度均有不同程度的降低,而煤样的最大燃烧速率增大且燃烧最大速率出现的温度前移;当煤粉样品中分别掺有3%的Na2CO3,BaCO3和CaCO3时,煤粉燃烧的活化能比纯煤粉分别降低了15.63%,12.39%和14.23%,且指前因子与活化能之间存在着线形关系,其关系为In(А)=0.2783E-12.882。  相似文献   

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氧化铜对硅酸三钙和硫铝酸钙矿物形成及共存的影响   总被引:9,自引:4,他引:5  
研究了CuO对含硫铝酸钙矿物硅酸盐水泥中硅酸三钙(C3S)和硫铝酸钙(C4A3S)矿物形成及共存的影响。借助化学分析和X射线衍射内标法分别测定了水泥熟料中C3S及C4A3S矿物的含量。用X射线衍射仪分析了熟料矿物组成,并采用差热分析和透射电镜分别研究了CuO对熟料形成特性和C3S晶体结构的影响。研究结果表明:生料中掺入生料质量0.1%的CuO,能降低水泥熟料的烧成温度。促进C3S和C4A3S两种矿物相互共存.提高熟料的强度。过量的CuO亦会降低C4A3S矿物的分解温度。  相似文献   

4.
罗力  张一敏  包申旭 《硅酸盐通报》2016,35(7):2024-2028
利用铁尾矿作为作硅铝质原料进行生料配料(熟料率值KH =0.97,SM =2.5,IM =1.5),其中C3S含量超过70%.在此空白生料的基础上分别掺入氟、硫和氟硫复合阴离子,各试样分别在1300℃,1350℃,1400℃和1450℃下煅烧30 min,然后测定熟料中f-CaO的含量,并计算C3S的形成活化能.通过差热分析和XRD分析,研究高C3S熟料的烧成过程.结果表明:氟、硫的掺入能够显著改善生料的易烧性,大幅降低C3S的活化能,促进熟料的烧成.单掺时硫比氟的效果要好,氟硫复掺比单掺效果好.生料的差热分析表明,氟、硫能够使石灰石的分解温度降低10 ~20℃,同时能促进熟料的液相烧结.在1450℃时复掺氟硫熟料的主要矿相是C3S,还有少量的C2S,C3A和C4AF,表明高C3S水泥熟料已经烧成.  相似文献   

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利用片状氧化铝、鳞片石墨、粉状Al、Si和Zn及酚醛树脂结合剂制造了AlO3-C质耐火材料的试样。片状氧化铝、鳞片石墨、Al及Si的数量比是固定的,而锌的加入量分别为0.5%、1.0%、2.0%及3.0%。试样于120~220℃下进行烘焙,历时24h,然后于1400℃在空气中烧成3h。利用电子显微镜及能量弥散式X射线荧光光谱测定法测定了制品的重量损失、脱碳层厚度、开口气孔率、体积密度及微观结构。加入2%锌的试样的特点是:脱碳层厚度及开口气孔率最低,而体积密度则最高。看来,此种材料应具有最好的抗氧化性。  相似文献   

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烷基化聚酯超分散剂改性纳米CaCO3及其在PVC中的应用   总被引:4,自引:0,他引:4  
探讨了不同改性剂、改性温度对纳米CaCO3的活化指数的影响,考察了改性纳米CaCO3前后中的DOP糊黏度和增塑剂吸收量的变化。结果表明:烷基化聚酯超分散剂干法改性纳米CaCO3比NDZ-201偶联剂湿法改性纳米CaCO3更有效,其最佳用量为4%,最佳改性温度为110℃。烷基化聚酯超分散剂改性纳米CaCO3/BOP糊黏度降低了87.6%,增塑剂吸收量降低了53.9%。烷基化聚酯超分散剂改性纳米CaCO3对PVC材料具有增强、增韧作用。  相似文献   

7.
粉煤灰制备片状氧化铝粉体   总被引:4,自引:2,他引:2  
谭宏斌 《陶瓷》2010,(2):20-22
在粉煤灰中加入一定量硫酸铝为原料,以硫酸钠为反应介质,研究了不同温度对试样产物的影响。结果表明:在1200℃温度条件下保温3h,试样的主要物相为α—Al2O3和硅铝酸钠,用HF酸溶去硅铝酸钠和试样中的杂质相,得到了较纯的片状α—Al2O3,片晶大小为4~7μm,厚度为0.1~0.3μm。  相似文献   

8.
邓美林 《无机盐工业》2007,39(5):45-46,62
介绍了选用低温结晶法,以水合肼副产碱渣为原料制备过碳酸钠的工艺。通过正交实验,确定了最佳工艺条件:碳酸钠与双氧水的物质的量比为1.0:(1.3~1.5),工业盐相对于碱渣加入量0.28kg/kg,反应温度0~10℃,反应时间30~45min。在最佳工艺条件下合成反应收率均可达到85%以上,产品质量达到化工行业标准。选择了3种稳定剂(X,Y,Z),将它们单独或组合进行过碳酸钠稳定实验,结果表明,复合稳定剂效果较好,且加入质量占物料总质量的0.35%~0.45%。稳定剂配比:X与Y的质量比2:1或X,Y,Z的质量比1:1:1。  相似文献   

9.
研究了掺杂CuO对C4A3矿物形成的影响。结果表明:在1300℃保温1h,3h的煅烧条件下,掺杂一定量的CuO,能使C4A3的形成量增加,但当CuO掺加质量分数超过0.3%时,C4A3含量会降低,保温时间延长对C4A3的形成不利。IR分析结果表明:CuO使C4A3的晶格发生了畸变。在石膏晶型转变前,掺杂适量的CuO可以促进C4A3的形成,同时可以使C4A3的形成温度降低,而且CuO的掺入会使石膏的分解温度降低,过量还会促进石膏的分解。  相似文献   

10.
聚酯超分散剂改性纳米碳酸钙及其应用研究   总被引:6,自引:0,他引:6  
研究了聚酯超分散剂改性纳米碳酸钙.探讨了不同改性剂和改性温度对活化指数的影响,考察了改性前后纳米碳酸钙DOP糊粘度和吸油量的变化。结果表明:聚酯超分散剂干法改性纳米CaCO3比NDZ-201偶联剂湿法改性纳米CaCO3更有效,其最佳用量为4%,最佳改性温度为110℃。聚酯超分散剂改性纳米CaCO3的DOP糊粘度降低了87.6%,吸油值降低了53.9%。聚酯超分散剂改性纳米CaCO3对PVC材料具有增强、增韧作用。  相似文献   

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Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.  相似文献   

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2008~2009年世界塑料工业进展   总被引:4,自引:1,他引:3  
收集了2008年7月~2009年6月世界塑料工业的相关资料,介绍了2008~2009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、环氧树脂、不饱和聚酯树脂)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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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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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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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   

18.
It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.  相似文献   

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