共查询到20条相似文献,搜索用时 281 毫秒
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化学结合磷酸镁水泥(MPC)是一种快硬、早强的新型胶凝材料,可用于混凝土结构的快速修补.通过三种不同细度1 700℃重烧氧化镁(M)和工业级KH2P04(P)制备钾基磷酸镁水泥,研究M/P摩尔比、MgO细度、硼砂掺量等因素对磷酸镁水泥凝结时间和力学性能的影响,以XRD和TG-DSC表征磷酸镁水泥的水化产物.实验结果表明,磷酸镁水泥最佳M/P在4~5之间,1d强度最高可达45.6 MPa; MgO粉末细度对磷酸镁水泥的凝结性能影响很大,MgO的细度应控制在2 000 ~3 000 cm2/g之间,符合该细度要求的M2具有最合适的凝结时间和最高的抗压强度;硼砂对磷酸镁水泥有一定缓凝作用,但对磷酸镁水泥早期强度影响很大,24 h后抗压强度几乎无差别.磷酸镁水泥的主要水化产物为MgKPO4·6H2O和水化凝胶,但在凝结较快的M3中有MgKPO4·H2O生成. 相似文献
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以化学纯CaCO3、4MgCO3·Mg(OH)2·5H2O、ZrO2、SiO2和(NH4)H2PO。微粉为原料,采用高温固相反应法合成了Ca4(1+x)/5Mg(1+x)/5Zr4Si2xP(6-2x)O24(CMZP)粉体,其中x=0、0.1、0.2、0.3。XRD测试结果表明在400℃下保温2h、1150℃下保温4h,能够合成单相的CMZP粉体,粉体千压成形后经冷等静压处理,在1350℃保温8h能烧结得到相对密度为97.5%的陶瓷试样,其平均抗弯强度为50MPa。 相似文献
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研究了并辛醇聚氧乙烯醚(C8H17(EO)4OH)磷酸酯的合成工艺条件对其耐碱渗透性的影响,得到以下最佳合成工艺:在强烈搅拌下,分批投P2P5,原料配比为n(C8H17(EO)4OH)/n(P2O5)=2.5,酯化温度70℃,酯化时间4h。在该条件下合成的异辛醇聚氧乙烯醚磷酸酯盐在质量浓度为220g/L的强烧碱溶液中测试其渗透时间为4s。 相似文献
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以工业纯ZrCl4、Si(OC2H5)4为前驱体,采用无溶剂的非水解溶胶-凝胶法合成了硅酸锆,研究矿化剂种类、矿化剂用量、前驱物配比对硅酸锆合成效果的影响。结果表明:以LiF为矿化剂、前驱物n(Si):n(Zr)=1.2:1、矿化剂用量n(Li):n(Si)=0.3:1、煅烧温度为700℃,可制备出合成率高达98.4%的硅酸锆。 相似文献
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以粉煤灰为主要原料,用CaCO3作为发泡剂,Na3PO4·12H2O作为稳泡剂,制备出了性能优良微晶泡沫玻璃。研究了发泡温度、发泡时间等因素对微晶泡沫玻璃性能的影响。结果表明,随着发泡温度的升高和保温时间的增加,体积密度均先减小后增大,最佳发泡温度1025℃,发泡时间30min。析出的晶体有钙长石CaAl2Si2O8、普通辉石Ca(Mg,Fe,Al)(Si,Al)2O6;密度为1.02g.cm-3;热膨胀系数为7.51×10-6/℃;抗压强度为19.2MPa;抗弯强度为16.3MPa。 相似文献
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液相法制备锆钒蓝色料的研究 总被引:1,自引:0,他引:1
介绍了以正硅酸乙酯Si(C2H5O4)、氧氯化锆(ZrOCl2)和氧氯化钒(VOCl3)等为原料,以水和乙醇为介质制备V-ZrSiO4蓝色料超细粉的方法。其中钒均匀地分散固溶在ZrSiO4中,通过系统改变Zr/Si(摩尔比)和V的固溶量可获得最佳呈色效果。通过XRD、DTA-TG和红外光谱的测试和分析明确了在加热过程中颜色变化与钒在ZrSiO4中固溶量的关系,及V^4 取代ZrSiO4中部分Zr^4 形成固溶体的结论。 相似文献
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以聚己二酸酐(PAA)和氯硅氧烷Si3C6H18O2C12(Si3)和Si5C10H30O4C12(Si5)为单体合成聚己二酸酐硅基酯。所得样品用1H-NMR、DSC、TGA和测特性黏数等手段对其进行了表征。考察了反应过程中反应时间、溶剂等因素的影响。所得样品用1H-NMR,DSC-TGA进行分析,结果较理想。测得多组样品特性黏数,显示所得产物具有高分子的特性。 相似文献
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乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。 相似文献
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D. G. Gordeev L. F. Gudarenko M. V. Zhernokletov V. G. Kudel’kin M. A. Mochalov 《Combustion, Explosion, and Shock Waves》2008,44(2):177-189
A semi-empirical equation of state for metals is described. Its capabilities are demonstrated by the example of the equation
of state for aluminum. New experimental data are presented on the location of the isentrope of aluminum for unloading from
the state at p = 229.71 GPa on the shock adiabat to an aerogel (SiO2) of density 0.08 g/cm3.
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Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 2, pp. 61–75, March–April, 2008. 相似文献
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Jorge Marcelo Romero Soledad Bustillo Hugo Enrique Ramirez Maisuls Nelly Lidia Jorge Manuel Eduardo Gómez Vara Eduardo Alberto Castro Alicia H. Jubert 《International journal of molecular sciences》2007,8(7):688-694
A thermochemical rather simple experimental technique is applied to determine the enthalpy of formation of Diperoxide of ciclohexanone. The study is complemented with suitable theoretical calculations at the semiempirical and ab initio levels. A particular satisfactory agreement between both ways is found for the ab initio calculation at the 6–311G basis This set level. Some possible extensions of the present procedure are pointed out. 相似文献
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A perturbation viscometer is a differential capillary viscometer that measures the logarithmic viscosity gradient of the viscosity-composition curve for gas mixtures. Measurements are made at different gas mixture compositions. Integration of the logarithmic viscosity gradients measured over the full composition range gives the mixture viscosity relative to the viscosity of one of the pure components of the gas mixture. This method is attractive because, for measurements of equal precision, integration of the gradients is potentially an order of magnitude more precise than measurement of the viscosities directly. It can also work at high and low temperatures and perhaps high pressures.The perturbation viscometer has been used to make measurements on ideal gas mixtures at ambient and elevated temperatures. The situation is more complicated when the gas mixtures are non-ideal. Extra effects due to density differences, molar volume change on mixing and differential thermal expansion may be measured in addition to the desired viscosity change producing systematic errors in the results. Thus, a more sophisticated apparatus is required. The standard perturbation viscometer has been modified to separate out the extra effects to permit measurement of the true change in viscosity. In addition, the theoretical operation of the modified apparatus has been revised to account for the design changes to permit calculation of the viscosity-composition profiles from the results.The apparatus has been tested using helium-HFC-125 mixtures and two new viscosity-composition profiles are presented for these mixtures at 23 and . Internal consistency tests have been used to confirm that the data produced are of high quality with an estimated uncertainty in the viscosity ratio data at of 0.9% and at of 1.5%. 相似文献
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醋酸纤维素取代基分布与性质的关系 总被引:9,自引:0,他引:9
分析了以吡啶为溶剂的醋酸纤维素的13C-NMR核磁共振谱,得出了三种不同位置羟基的取代度。结合X—射线和DSC分析,初步说明具有相同取代度但未经水解和经过水解的醋酸纤维素(CA) 性质上的差异是由于三个羟基上的取代度分布不同及消晶程度差异所致。 相似文献