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纳米及微米级六角片状氢氧化镁的制备 总被引：2，自引：2，他引：0
以氯化钠为底料,水氯镁石和氢氧化钠为原料,不添加任何添加剂,采用双柱沉淀—水热法制备粒度分布均匀、分散性良好的氢氧化镁。研究了进料速度、2N_(Mg)/N_(Na)、物料浓度、水热温度、水热时间等因素对氢氧化镁粒径、形貌、过滤性能的影响。通过粒度分析仪、X射线衍射仪、低真空扫描电子显微镜对产品的粒度分布、结构和形貌进行了表征。结果表明,本研究得到的样品分散性好,粒度分布均匀,形貌为规则的六角片状,粒径为400~600 nm的纳米级氢氧化镁或者1~2μm的微米级氢氧化镁。 相似文献
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张国栋 《成都信息工程学院学报》1997,(4)
用改进的射线光学理论和等效球Ｍｉｅ理论，计算了若干冰晶和冰晶尺度分布在太阳光谱区中一系列波长上的光学特性和散射特性，详细分析了Ｍｉｅ散射计算的误差，并假定冰云光学特性有１０％误差的情况下，用Ｄｅｌｔａ－Ｅｄｄｉｎｇｔｏｎ近似对所引起的冰云辐射特性的误差进行了数值试验。结果表明，沿用已久的等效球Ｍｉｅ理论因计算冰云光学特性在波长小于２．６μｍ波段误差过大，将引起冰云辐射特性有显著误差，最后提出了计算冰云光学特性的新方案。 相似文献
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新疆大卡拉苏花岗伟晶岩锥状绿柱石矿物特征 总被引：1，自引：0，他引：1
在自然界中绿柱石多为柱状，往往呈杂乱无序状晶出，锥状绿柱石非常少见。大卡拉苏花岗伟晶中的六方锥状绿柱石，垂直花岗伟晶岩脉壁定向晶出，与熔浆期后钠质交代作用关系密切。 相似文献
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A laser-heated diamond-anvil cell that is capable of operating up to a pressure of 63 GPa, with X-ray diffraction facilities using a synchrotron radiation source at the SPring-8, has been developed to observe the compressibility of a hexagonal aluminous phase, [K0.15Na1.66Ca0.11Mg1.29Fe2+ 0.86Al3.13Ti0.09Si1.98] Σ9.27O12. The hexagonal aluminous phase is a potassium host mineral from the subducted oceanic crust in the Earth's lower mantle. A sample was heated using a YAG laser at each pressure increment to relax the deviatoric stress in the sample. X-ray diffraction measurements were carried out at 300 K using an angle-dispersive technique. Pressure was measured using an internal platinum pressure calibrant. The observed unit-cell volumes were used to obtain a third-order Birch–Murnaghan equation of state: unit-cell volume V o=185.94(±16) Å3, density ρ o=4.145 g/cm3, and bulk modulus K o=198(±3) GPa when the first pressure is derivative of the bulk modulus K ′ o is fixed to 4. The density of hexagonal aluminous phase is lower than that of coexisting Mg-perovskite in the subducted oceanic crust. 相似文献
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T. Shinmei T. Sanehira D. Yamazaki T. Inoue T. Irifune K. Funakoshi A. Nozawa 《Physics and Chemistry of Minerals》2005,32(8-9):594-602
Thermal equation of state of an Al-rich phase with Na1.13Mg1.51Al4.47Si1.62O12 composition has been derived from in situ X-ray diffraction experiments using synchrotron radiation and a multianvil apparatus at pressures up to 24 GPa and temperatures up to 1,900 K. The Al-rich phase exhibited a hexagonal symmetry throughout the present pressure–temperature conditions and the refined unit-cell parameters at ambient condition were: a=8.729(1) Å, c=2.7695(5) Å, V 0=182.77(6) Å3 (Z=1; formula weight=420.78 g/mol), yielding the zero-pressure density ρ0=3.823(1) g/cm3 . A least-square fitting of the pressure-volume-temperature data based on Anderson’s pressure scale of gold (Anderson et al. in J Appl Phys 65:1534–543, 1989) to high-temperature Birch-Murnaghan equation of state yielded the isothermal bulk modulus K 0=176(2) GPa, its pressure derivative K 0 ′ =4.9(3), temperature derivative (?K T /?T) P =?0.030(3) GPa K?1 and thermal expansivity α(T)=3.36(6)×10?5+7.2(1.9)×10?9 T, while those values of K 0=181.7(4) GPa, (?K T /?T) P =?0.020(2) GPa K?1 and α(T)=3.28(7)×10?5+3.0(9)×10?9 T were obtained when K 0 ′ was assumed to be 4.0. The estimated bulk density of subducting MORB becomes denser with increasing depth as compared with earlier estimates (Ono et al. in Phys Chem Miner 29:527–531 2002; Vanpeteghem et al. in Phys Earth Planet Inter 138:223–230 2003; Guignot and Andrault in Phys Earth Planet Inter 143–44:107–128 2004), although the difference is insignificant (<0.6%) when the proportions of the hexagonal phase in the MORB compositions (～20%) are taken into account. 相似文献
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The automatic detection of geological features such as faults and channels is a challenging problem in today's seismic exploration industry. Edge detection filters are generally applied to locate features. It is desirable to reduce noise in the data before edge detection. The application of smoothing or low‐pass filters results in noise suppression, but this causes edge blurring as well. Edge‐preserving smoothing is a technique that results in simultaneous edge preservation and noise suppression. Until now, edge‐preserving smoothing has been carried out on rectangular sampled seismic data. In this paper, an attempt has been made to detect edges by applying edge‐preserving smoothing as a pre‐processing step in the hexagonally sampled seismic‐data spatial domain. A hexagonal approach is an efficient method of sampling and has greater symmetry than a rectangular approach. Here, spiral architecture has been employed to handle the hexagonally sampled seismic data. A comparison of edge‐preserving smoothing on both rectangular and hexagonally sampled seismic data is carried out. The data used were provided by Saudi Aramco. It is shown that hexagonal processing results in well‐defined edges with fewer computations. 相似文献
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T. Sanehira T. Irifune T. Shinmei F. Brunet K. Funakoshi A. Nozawa 《Physics and Chemistry of Minerals》2006,33(1):28-34
In situ X-ray diffraction study was conducted to identify the crystal structure of the “Al-phase”, which was previously reported
to form in basaltic compositions at pressures and temperatures of the uppermost part of the lower mantle. Le Bail whole-pattern
fitting method was adopted to investigate the structure of the Al-phase under high pressure and temperature as well as ambient
conditions. Observed patterns were satisfactorily fitted using the “hexagonal phase” with space group P63/m (plus minor amount of garnet) under both of these conditions. On the other hand, the calcium ferrite structure model proposed
in some earlier studies based on quench experiments yielded profile-fitting results at significantly lower confidence levels,
particularly at simultaneous high pressure and high temperature conditions, suggesting that this phase may not form in oceanic
crust materials subducted in the uppermost lower mantle. The difference in densities of hexagonal and calcium ferrite phases,
however, is only ~1% under pressures and temperatures of the uppermost part of the lower mantle conditions, which yields a
negligible effect on the bulk density of the subducted oceanic crust. 相似文献
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