High pressure behaviour of lead feldspar (PbAl2Si2O8)     

M. Tribaudino  P. Benna  E. Bruno  M. Hanfland 《Physics and Chemistry of Minerals》1999,26(5):367-374

An in situ high pressure powder diffraction study, using high-brilliance synchrotron radiation, on lead feldspar (PbAl₂Si₂O₈) was performed. Two samples, with Q _od=0.68 and 0.76, were loaded in a diamond anvil cell and were compressed up to 11 GPa. Up to P=7.1 GPa the only phase present is lead feldspar. In the range 7.1–9.4 GPa sudden changes in the position of the reflections suggest the transformation of lead feldspar to a new phase (probably feldspar-like). The absence of split that would be compatible with triclinic symmetry rules out the monoclinic-triclinic transition, that was reported for the structurally similar strontium feldspar. At P>9.4 GPa some new extra reflections not indexable in the feldspar cell are present as well. During decompression the lead feldspar was the only phase present at P<6 GPa. Peak enlargement was observed with pressure, probably preliminary to amorphization. However almost complete amorphization was observed only after fortuitous shock compression at ∼18 GPa; the crystallinity was recovered at room pressure after decompression. The bulk modulus for lead feldspar was K=71.0(9) and 67.6(1.2) GPa for the two samples, in the range reported for feldspars. The cell parameters show a compression pattern which is similar to that observed in anorthite, with Δa/a ₀>Δc/c ₀>Δb/b ₀; comparison with the high temperature behaviour shows that for lead feldspar the strain tensor with pressure is more isotropic and the deformation along a is less prominent. A turnover in the behaviour of the β angle with pressure suggests a change in the compression behaviour at P∼2 GPa. Rietveld refinement of the Pb coordinates was performed in a series of spectra with pressure ranging from 0.6 to 6.5 GPa. The combined analysis of cell parameters and Pb coordinates with pressure showed that the compression of the structure is mainly achieved by an approach of Pb atoms along a *. Received: 21 July 1998 / Revised, accepted: 13 October 1998  相似文献   

新矿物(1994.1—1994.12)     

黄蕴慧  蔡剑辉  曹亚文 《岩石矿物学杂志》1999,18(1):50-64

本文以表格形式列举了１９９４年１月至１９９４年１２月经《国际矿物学协会（ＩＭＡ）新矿物与矿物命名委员会（ＣＮＭＭＮ）》批准并在各国矿物学杂志上发表的３６个新矿物的中文英文名称、化学式及其他数据。数据依次为：矿物的晶系、空间群、晶胞参数、主要粉晶数据（Ｉ、ｈｋｌ）、物理性质（晶形、颜色、条痕、光泽、解理、发光、硬度、密度等）、光学性质（一、二轴晶,正、负光性,折光率,反射率,双反射,２Ｖ,色散,吸收性,多色性等）、产状、共生矿物等。  相似文献   

金刚石微粉质量的评定     

谈耀麟 《矿产与地质》1999,13(3):191-193

从用户和生产厂家的观点阐述如何评定金刚石微粉的质量。着重论述根据金刚石微粉的粒度、颗粒形状、锐利性、抗磨耗性和强度来评定金刚石微粉的质量  相似文献   

CCD单晶衍射仪进行单晶德拜衍射   总被引：9，自引：1，他引：8  

李国武  施倪承  马喆生  熊明  陈荣秀 《矿物学报》2005,25(1):9-14

利用CCD单晶衍射仪的旋转图功能,并进行了支持软件的开发,实现了单晶体拍摄德拜衍射图,提出了利用单晶体获取粉晶衍射图谱的一种新方法。对比实验表明,该方法相当实用而有效,对稀有贵重样品的衍射分析具有十分重要的意义。  相似文献   

X射线粉晶衍射法在变粒岩鉴定与分类中的应用     

伍月  迟广成  刘欣 《岩矿测试》2020,39(4):546-554

变粒岩的鉴定通常以显微镜鉴定技术为主,但在显微镜下区分颗粒细小的长石、石英及绿泥石、蒙脱石、云母等层状硅酸盐矿物十分困难,仅通过显微鉴定技术对变粒岩进行定名可能产生较大误差,这对地质填图和原岩恢复工作会造成一些偏差,导致得出错误的地质结论。随着X射线衍射分析技术的发展,该技术已广泛应用于矿物学和岩石学的研究,本研究将结合X射线粉晶衍射技术,对显微镜下难以区分的细小矿物进行鉴定。共选用23件变粒岩样品,利用X射线粉晶衍射分析和显微镜岩石薄片鉴定技术,对变粒岩矿物组分进行检测,用X射线粉晶衍射矿物半定量分析结果验证岩石薄片鉴定结果准确性。显微镜岩石薄片鉴定结果与X射线粉晶衍射物相分析结果对比显示,10件样品定名一致,其余13件样品详细定名有差异。通过分析产生差异的原因,可以认为显微镜岩石薄片鉴定优势在于能确定岩石结构和构造,以及常见矿物组分;X射线粉晶衍射法的优势在于能检测出显微镜下较难区分的细小石英和长石颗粒的相对含量,并能检测出颗粒较小的绿泥石、蒙脱石及云母等层状硅酸盐矿物,该方法对含量较少、颗粒较细的矿物检测效果较好。实验证明将显微岩石薄片鉴定技术和X射线粉晶衍射技术相结合,才能更准确对变粒岩进行定名,为地学研究提供更符合客观实际的技术数据和分析结论。  相似文献   

X射线荧光光谱法测定海洋沉积物中的41种元素及氧化物   总被引：4，自引：0，他引：4  

孙萱  宋金明  温廷宇  刘瑶 《海洋科学》2018,42(4):79-88

海洋沉积物样品具有盐分含量高、吸水性强、基体复杂、不同元素浓度差异悬殊等特点,其元素定量分析无论在样品前处理以及分析测试方法都有不少问题。特别是常微量元素很难用同一种方法进行测定,波长色散X射线荧光光谱可以很好的解决这一难题。因此,本文构建了粉末压片制样波长色散X射线荧光光谱法直接测定海洋沉积物样品中41种元素或其氧化物(Na_2O、MgO、Al_2O_3、SiO_2、P、S、Cl、K_2O、CaO、Fe_2O_3、Sc、Ti, V、Cr、Mn、Co、Ni、Cu、Zn、Ga、As、Br、Rb、Sr、Y、Zr、Nb、Mo、Cd、Sn、Sb、Ba、La、Hf、W、Pb、Bi、Ce、Nd、Th、U)的方法。样品在30 t的压力下保压30 s,制备的样片坚固光滑、吸潮性小。针对海洋地质样品的多样性,通过多种校准标准品拟合曲线进行测量,降低了检出限,优化了测量条件。用经验系数、理论α系数与经验系数相结合和康普顿散射线内标法校正元素间的基体效应。对土壤成分标准物质GBW07408和海洋沉积物成分标准物质GBW07315进行精密度考察,大部分元素的方法精密度提高至0.16%~3.87%,绝大多数主次痕量元素的测量精密度(RSD)小于4%,方法检出限为0.8~220μg/g。对渤海湾三个站位沉积物样品41种元素或其氧化物测定,结果表明,测定方法的重复性好,经国家一级标准物质验证,表明方法准确可靠,能满足日常分析要求。该方法对水系沉积物、土壤等陆地地化样品同样适用。  相似文献   

参苓白术散对NAFLD大鼠肝细胞、Kupffer细胞mTOR通路相关基因及蛋白表达影响的实验研究          下载免费PDF全文

徐拥建  张云城  冯高飞 《应用海洋学学报》2020,36(7):147

目的：观察参苓白术散对非酒精性脂肪性肝病（NAFLD）大鼠肝细胞、Kupffer细胞、哺乳动物雷帕霉素靶蛋白（mTOR）通路相关基因及蛋白表达的影响,以阐明参苓白术散抗NAFLD的作用机制。方法：将80只大鼠随机分为正常组,模型组及参苓白术散低、高剂量组。对模型组、各药物组连续8周喂养高脂饲料制备NAFLD大鼠模型。造模成功后采用油红O染色观察肝组织病理变化;Ⅳ型胶原酶离体循环灌注法分离肝细胞、Kupfer细胞;全自动生化仪检测血清总胆固醇（TC）、三酰甘油（TG）;酶联免疫吸附法测定肝细胞及Kupffer细胞血管内皮生长因子（VEGF）、干扰素（IFN）-γ含量;实时荧光定量PCR及蛋白质印迹法（Western blot）检测大鼠肝细胞及Kupffer细胞脑内富含的小G蛋白Ras同系物（Rheb）、mTOR复合物1（mTORC1）、核糖体S6蛋白激酶1（S6K1）和真核细胞翻译起始因子4E-结合蛋白1（4E-BP1）mRNA和蛋白表达。结果：模型组大鼠肝组织存在严重的脂质蓄积。血清TC、TG,肝细胞、Kupffer细胞,VEGF、IFN-γ含量,以及Rheb、mTORC1、S6K1、4E-BP1 mRNA和蛋白表达水平较正常组显著升高（P<0.01）,说明造模成功。与模型组比较,各药物干预组血清TC、TG,肝细胞、Kupffer细胞,VEGF、IFN-γ含量,以及Rheb、mTORC1、S6K1、4E-BP1 mRNA和蛋白表达均有不同程度的下调（P<0.05或P<0.01）。其中参苓白术散高剂量组下调趋势最为显著,与低剂量组比较,差异均有统计学意义（P<0.05或P<0.01）。结论：参苓白术散抗NAFLD的作用机制可能与抑制肝细胞及Kupffer细胞mTOR通路中Rheb、mTORC1、S6K1、4E-BP1基因及蛋白表达有关。  相似文献   

Preparation and study on performance of submicron nickel powder for multilayer chip positive temperature coefficient resistance     

陈勇  龚树萍  傅邱云  郑志平  黄日明  苏鹏 《海洋学报(英文版)》2010,29(11)

Base metal nickel is often used as the inner electrode in multilayer chip positive temperature coefficient resistance (PTCR). The fine grain of ceramic powders and base metal nickel are necessary. This paper uses reducing hydrazine to gain submicron nickel powder whose diameter was 200--300 nm through adjusting the consumption of nucleating agent PVP properly. The submicron nickel powder could disperse well and was fit for co---fired of multilayer chip PTCR. It analyes the submicron nickel powder through x-ray Diffraction (XRD) and calculates the diameter of nickel by PDF cards. Using XRD analyses it obtains several conclusions: If the molar ratio of hydrazine hydrate and nickel sulfate is kept to be a constant, when enlarging the molar ratio of NaOH/Ni²⁺, the diameter of nickel powder would become smaller. When the temperature in the experiment raises to 70--80℃, nickel powder becomes smaller too. And if the molar ratio of NaOH/Ni²⁺ is 4, when molar ratio of (C₂H₅O)₂/Ni²⁺ increases, the diameter of nickel would reduce. Results from viewing the powders by optical microscope should be the fact that the electrode made by submicron nickel powder has a better formation and compactness. Furthermore, the sheet resistance testing shows that the electrode made by submicron nickel is smaller than that made by micron nickel.  相似文献   

海藻在南美白对虾饲料中的应用研究   总被引：7，自引：0，他引：7       下载免费PDF全文

周歧存  肖风波 《海洋科学》2003,27(3):66-69

在以鱼粉、豆粕等为主要蛋白源的实用饲料中添加不同含量的海藻粉（0％，3％，6％，9％和12％），喂养体质量为0.40-0.61g的南症状白对虾幼虾30d。结果表明，饲料中添加3％组的南症状白对虾体增重和蛋白质效率显高于其它各添加组，而未添加海藻粉组生长最差；添加3％海藻组饲料系数最低，而未添加组和添加9％和12％组最高；对对虾体成分的分析显示不同含量的海藻粉显影响对虾体灰分、脂肪和总糖的含量。  相似文献