基于XRF的紫金山铜矿床硫地质特征

福建紫金山铜矿床属高硫浅成中低温热液矿床,矿石中主要含铜矿物为蓝辉铜矿、铜蓝和硫砷铜矿等,且铜矿物与黄铁矿密切共生。由于铜矿石中硫含量较高,导致铜精矿中硫含量超标,w(S)/w(Cu)比值为2.0~2.1,远高于冶炼要求的1.15~1.20,影响其经济价值。使用X射线荧光(XRF)光谱分析对紫金山铜矿中S元素的分布进行数字化研究,查明硫的空间分布规律和赋存状态,划分铜矿石类型,为紫金山铜矿今后的采选工作提供参考。     

16排螺旋CT下肢低剂量造影剂血管成像可行性研究

目的:探讨l6排螺旋CT低剂量造影剂下肢血管成像的可行性. 资料与方法 66例下肢CT血管成像(CTA)分为3组,采用不同的造影剂量:150 ml,120ml 和80ml.根据原始图像和最大强度投影(MIP)重建图像评价,3组下肢动脉显示程度;并测量动脉内造影剂的浓度.结果:下肢动脉在3组病例中均清晰显示.显示程度评分,3组间无统计学差异.3组动脉内的造影剂浓度均维持在较高的水平,统计学无显著性差异. 结论 l6排螺旋CT下肢血管成像使用低剂量造影剂可以满足临床需要.     

Magnetized accretion flows: effects of gas pressure

We study how axisymmetric magnetohydrodynamic (MHD) accretion flows depend on γ adiabatic index in the polytropic equation of state. This work is an extension of Mościbrodzka & Proga, where we investigated the γ dependence of two-dimensional Bondi-like accretion flows in the hydrodynamical (HD) limit. Our main goal is to study if simulations for various γ can give us insights into the problem of various modes of accretion observed in several types of accretion systems, such as black hole binaries (BHBs), active galactic nuclei (AGN) and gamma-ray bursts. We find that for  γ≳ 4/3  , the fast-rotating flow forms a thick torus that is supported by rotation and gas pressure. As shown before for  γ= 5/3  , such a torus produces a strong, persistent bipolar outflow that can significantly reduce the polar funnel accretion of a slowly rotating flow. For low γ, close to 1, the torus is thin and is supported by rotation. The thin torus produces an unsteady outflow which is too weak to propagate throughout the polar funnel inflow. Compared to their HD counterparts, the MHD simulations show that the magnetized torus can produce an outflow and does not exhibit regular oscillations. Generally, our simulations demonstrate how the torus thickness affects the outflow production. They also support the notion that the geometrical thickness of the torus correlates with the power of the torus outflow. Our results, applied to observations, suggest that the torus ability to radiatively cool and become thin can correspond to a suppression of a jet as observed in the BHBs during a transition from a hard/low to soft/high spectral state and a transition from a quiescent to hard/low state in AGN.     

九种现代双壳类壳体物相组成的对比研究

利用X射线衍射分析技术,对黄东海常见的9种现代双壳类壳体进行了物相分析,结果表明这些双壳类壳体分别属于三种类型,即文石质壳、方解石质壳、文石+方解石混合质壳。其中,菲律宾蛤仔(Ruditapesphilippinarum)、中国蛤蜊(Mactrachinensis)、四角蛤蜊(Mactraveneriformis)、薄片镜蛤(Dosinialaminata)、毛蚶(Scapharcasubcrenata)属于文石质壳,长牡蛎(Crassostreagigas)、中国不等蛤(Anomiachinensis)、海湾扇贝(Argopectenirradieus)属于方解石质壳,紫贻贝(Mytilusedulis)属于文石+方解石质的混合质壳;双壳类壳体物相组成与其生活方式有着一定的联系,营底栖埋入式生活者趋于形成文石质壳,底栖固着生活方式者趋于形成方解石质壳或混合质壳;不同大小的菲律宾蛤仔(Ruditapesphilippinarum)的物相组成上几乎没有差别,表明其壳体物相组成不受生命效应的影响。     

Elastic behavior of vanadinite,Pb<Subscript>10</Subscript>(VO<Subscript>4</Subscript>)<Subscript>6</Subscript>Cl<Subscript>2</Subscript>, a microporous non-zeolitic mineral

The high-pressure behavior of a vanadinite (Pb₁₀(VO₄)₆Cl₂, a = b = 10.3254(5), c = 7.3450(4) Å, space group P6₃/m), a natural microporous mineral, has been investigated using in-situ HP-synchrotron X-ray powder diffraction up to 7.67 GPa with a diamond anvil cell under hydrostatic conditions. No phase transition has been observed within the pressure range investigated. Axial and volume isothermal Equations of State (EoS) of vanadinite were determined. Fitting the P–V data with a third-order Birch-Murnaghan (BM) EoS, using the data weighted by the uncertainties in P and V, we obtained: V ₀ = 681(1) Å³, K ₀ = 41(5) GPa, and K′ = 12.5(2.5). The evolution of the lattice constants with P shows a strong anisotropic compression pattern. The axial bulk moduli were calculated with a third-order “linearized” BM-EoS. The EoS parameters are: a ₀ = 10.3302(2) Å, K ₀(a) = 35(2) GPa and K′(a) = 10(1) for the a-axis; c ₀ = 7.3520(3) Å, K ₀(c) = 98(4) GPa, and K′(c) = 9(2) for the c-axis (K ₀(a):K ₀(c) = 1:2.80). Axial and volume Eulerian-finite strain (fe) at different normalized stress (Fe) were calculated. The weighted linear regression through the data points yields the following intercept values: Fe _a (0) = 35(2) GPa for the a-axis, Fe _c (0) = 98(4) GPa for the c-axis and Fe _V (0) = 45(2) GPa for the unit-cell volume. The slope of the regression lines gives rise to K′ values of 10(1) for the a-axis, 9(2) for the c-axis and 11(1) for the unit cell-volume. A comparison between the HP-elastic response of vanadinite and the iso-structural apatite is carried out. The possible reasons of the elastic anisotropy are discussed.     

X射线荧光光谱法同时测定白云岩中氧化钙和氧化镁等主次量组分

针对白云岩主次量组分同时测定中存在的问题,采用熔融玻璃片和粉末压片法制样(运用熔片-压片法相结合),选用有关的国家一级标准物质和省二级标准物质,以经验α系数法和散射线内标法校正元素谱线重叠干扰和基体效应,采用X射线荧光光谱法对白云岩样品中的氧化钙、氧化镁、氧化铝、二氧化硅、磷、氧化锰、全三氧化二铁和硫8个组分进行测定,分析结果与标准值或化学值吻合,各组分12次重复测定的相对标准偏差小于10%。方法操作简便、快捷。     

熔片制样-X射线荧光光谱法测定煤灰样品中主次量组分

采用混合熔剂熔融制备样片,用AxiosX射线荧光光谱仪测定煤灰样品中二氧化硅、氧化铝、氧化铁、氧化镁、氧化钙、氧化钠、氧化钾、二氧化钛、二氧化锰、五氧化二磷和三氧化硫等11种组分。重点研究了熔样比、熔样温度和标准样品的制备,解决了分析硫的难题。用基本参数法校正基体效应,分析方法的精密度(RSD,n=10)各组分均小于3%。用煤灰国家一级标准物质验证,结果与标准值相符。     

波长色散X射线荧光光谱法同时测定钨精矿中主次量组分

建立了采用波长色散X射线荧光光谱测定钨精矿中三氧化钨、锰、铁、氧化钙、二氧化硅、锡、钼、铜、铋、铅、锑、锌、镉、铬等14个主次量组分的方法。采用四硼酸钠和四硼酸锂混合熔剂熔融制样,以高纯物质人工配制校准标准样品,公共背景法进行背景校正,采用可变理论α影响系数法校正基体效应。方法的准确性、精密度达到了传统分析方法的要求,分析时间大大缩短,具有较好的实用价值。     

X射线荧光光谱法同时测定地质样品中铌钽锆铪铈镓钪铀等稀有元素

采用粉末压片法制样,选用标准样品,以经验α系数和散射线内标法校正基体效应和元素谱线重叠干扰,使用ZSXPrimusⅡX射线荧光光谱仪对一般地质样品中的铌、钽、锆、铪、铈、镓、钪、铀等稀有元素进行测定,分析结果与标准值和参考值吻合,12次测定的相对标准偏差(RSD)小于10%。     

利用中国地壳运动观测网络的GPS资料对太阳耀斑的监测及分析

利用中国地壳运动观测网络的GPS资料对2000年7月14日的太阳耀斑进行监测和分析,介绍一种值得探讨的耀斑爆发前可能存在的"前兆"现象.