粉末压片制样波长色散X射线荧光光谱法测定钼矿石中9种元素   总被引：2，自引：2，他引：0  

李清彩  赵庆令 《岩矿测试》2014,33(6):839-843

X射线荧光光谱(XRF)分析方法中,采用粉末压片制样存在粒度效应和矿物效应等问题,但当样品在一定的粒度、压制压力及压制时间条件下,矿物效应和粒度效应仅仅对钠、钙等轻元素的测试有影响,而对钼、铜、铅等元素的测试并无影响。基于此本文建立了粉末压片制样波长色散XRF直接测定钼矿石中Mo、W、Cu、Pb、Zn、F、S、As、Bi等9种元素的方法。采用价格低廉的低压聚乙烯粉作衬垫镶边材料,样品在35 t的压力下压制30 s,制备的样片坚固光滑、吸潮性小,长期保存不发生形变,消除了粒度效应。选用自制的钼含量呈梯度变化的钼矿石样品及钼矿石、钨矿石、铜矿石、铅矿石、铋矿石、锌矿石等国家标准物质作为校准样品建立标准曲线,降低了矿物效应,采用经验系数法消除谱线重叠和基体干扰。本方相对标准偏差小于2.1%,各元素的测定结果与电感耦合等离子发射光谱法等其他方法测量值吻合。与已报道的玻璃熔融和粉末压片制样方法相比较,检出限较低,如钼的检出限为3.67 μg/g,比玻璃熔融法的检出限(450 μg/g或24 μg/g)要低得多;砷的检出限为1.13 μg/g,低于其他粉末压片法的检出限(7.8 μg/g)。本方法提出了克服粒度效应及光谱诸干扰因素影响的详细解决方案,有利于XRF法应用于定量分析基体组成复杂的钼矿石。  相似文献   

The Phototropism of Jurassic Petrified Wood in North China Plate     

JIANG Zikun  LIU Benpei  HUANG Min  DENG Shenghui  LU Yuanzheng  LIU Lu  LI Mingming  DONG Shuxin  WANG Yongdong 《《地质学报》英文版》2014,88(5):1352-1355

Trees on the side directly exposed to sunlight generally grow faster than on the opposite side, a phenomenon termed plant phototropism. There are in situ vertical trunks of silicified wood in the Xiadelongwan area of Yanqing County, north Beijing, where the first National Geologic Park of Petrified Wood of China has been built since 2002. A few trunks have well-preserved growth rings. One petrified stump from the formation shows a positive phototropism direction of SW230°. As compared with the modern normal growth stumps in Beijing plain area, which have a positive phototropism direction of SW210 °± 5°, the evidence of wood phototropism supports the conclusion of previous palaeomagnetic studies that the North China Plate has rotated clockwise since the Late Jurassic. The known petrified wood stumps in the Yanshan-Liaoning area are mainly found from the strata of 165-136 Ma, which corresponds to the main stage of the Yanshanian Movement.  相似文献   

能量色散X射线荧光光谱仪现场快速测定多金属矿中17种组分   总被引：3，自引：2，他引：1  

龙昌玉  李小莉  张勤  李国会 《岩矿测试》2010,29(3):313-315

直接使用粉末样品,用Minipal 4便携式能量色散X射线荧光光谱仪测定多金属矿样品中的三氧化二铝、氧化镁、二氧化硅、氧化钾、氧化钙、三氧化二铁、硫、铜、锰、锌、铋、锑、铅、镓、银、砷、锡等17种组分,方法简便、快速,用多金属矿石国家一级标准物质验证,分析结果与标准值基本符合;精密度试验表明,各组分的相对标准偏差(RSD,n=12)均小于12%,能够满足矿山和野外现场快速测定的要求。  相似文献   

回收塑料-木材纤维复合材料的工艺及性能     

王正  赵行志  郭文静 《天文爱好者》2005,(1)

该文利用聚苯乙烯、聚乙烯和聚丙烯等 3种回收塑料与木材纤维复合制备复合材料 ,分析不同回收塑料种类、木材纤维与塑料不同质量比和热压温度等工艺条件对复合材料物理力学性能的影响 .结果表明 :3种回收塑料中回收聚苯乙烯塑料性能最好 ,回收聚丙烯塑料其次 ,回收聚乙烯塑料最差 .木塑质量比 5 0∶5 0效果最好 .塑料含量低时 ,内结合强度和拉伸强度低 ,吸水厚度膨胀率高 ;塑料含量过高时 ,静曲强度和弹性模量降低 .热压温度在1 90℃效果最好 .温度过低时 ,静曲强度、弹性模量、拉伸强度和内结合强度较差 ;温度过高时 ,木材纤维降解加剧 ,塑料少量溢出 ,性能反而有所下降 .通过极差和方差分析知 ,本研究F值的最佳工艺条件为 :采用回收聚苯乙烯、木塑质量比 5 0∶5 0、热压温度 1 90℃ .  相似文献   

云南省松材线虫病风险评估GIS平台开发   总被引：1，自引：0，他引：1  

沈安平  石雷  周汝良 《云南地理环境研究》2011,23(1):38-41,46

松材线虫病被称为松树的＂癌症＂。云南省针叶树种面积大,松材线虫寄主多,地形复杂,虫病防治难度大。综合运用.NET平台、ArcEngine组件技术、ArcSDE空间数据库引擎技术、SQL Server数据库技术,在云南省气象、空间、松材线虫数据基础上,建立一个云南省松材线虫病风险评估GIS平台,主要包括图层控制、风险评估、疫点操作、地图显示、专题图输出等功能,对云南省松材线虫病疫情进行更加精细化、标准化、可视化的评估。  相似文献   

三种裸子植物化石木的研究     

杨家驹  齐国凡  徐瑞瑚  杨礼茂 《国土资源》1996,(4)

本文研究了我国长江北岸湖北省武汉市新洲县阳逻镇北部晚第三纪的三种裸子植物化石木。它们是水松ＧｌｙｐｔｏｓｔｒｏｂｕｓｐｅｎｓｉｌｉｓＫ．Ｋｏｃｈ，武汉柏本ＣｕｐｒｅｓｓｕｓｗｕｈａｎｅｎｓｉｓＪ．ＪＹａｎｇｓｐ．ｎｏｖ．和武汉刺柏ＪｕｎｉｐｅｒｕｓｗｕｈａｎｅｎｓｉｓＪ．Ｊ．Ｙａｎｇｓｐ．ｎｏｖ，这些化石本的发现，给研究我国裸子植物提供了良好的依据．此外，对１９９０年发表于《林业科学》（２６卷４期）上的湖北柏木和河南松化石木也给了拉丁种名，它们分别是ＣｕｐｒｅｓｓｕｓｈｕｂｅｉｓｎｓｉｓＪ．Ｊ．Ｙａｎｇｓｐｎｏｖ．和ｐｉｎｕｓｈｅｎａｎｅｎｓｉｓＪ．Ｊ．Ｙａｎｇｓｐ．ｎｏｖ．  相似文献   

辽宁北部地区下白垩统木化石及其古气候意义     

丁秋红  李晓海  李文博  张志斌  陈树旺  张健  孙守亮  张渝金 《地质与资源》2022,31(1):13-20,12

对辽宁北部地区下白垩统沙海组木化石进行的木材解剖学及系统分类学研究显示,木化石均为硅化保存的松柏类裸子植物次生木质部,分别属于Protocupressinoxylon、Protopiceoxylon和Xenoxylon等3个分类群.当前木化石新材料生长轮清晰,早晚材比率在0.84～64之间,年平均敏感度在0.23～0....  相似文献   

Repeated high flows drive morphological change in rivers in recently deglaciated catchments     

Lawrence J. B. Eagle  Jonathan L. Carrivick  Alexander M. Milner  Lee E. Brown  Megan J. Klaar 《地球表面变化过程与地形》2021,46(7):1294-1310

Climate change is decreasing glacier cover and increasing the frequency and magnitude of precipitation-driven high flows and floods in many regions of the world. Precipitation may become the dominant water source for river systems in recently deglaciated catchments, with major rainfall events driving significant changes in river channel morphology. Few studies, however, have examined river channel response to repeated precipitation-driven high flows. In this study, we measured the geomorphological condition of four low-order rivers in recently deglaciated catchments (70–210 years ice free) before and after a series of repeated precipitation-driven high flows during summer 2014. High flows drove substantial initial morphological change, with up to 75% change in baseflow channel planform position and active channel form change from pre- to post-high flow. Post-high flow years were associated with increased instream wood and geomorphological complexity at all but the youngest river. Channel changes were part of an active relaxation stage at all rivers, where channels continued to migrate, and complexity varied through time. Overall, these measurements permit us to propose a conceptual model of the role of geomorphologically effective high flows in the context of paraglacial adjustment theory. Specifically, we suggest that older rivers in recently deglaciated catchments can undergo a short-term (<10 years) increase in the rate of geomorphological development as a result of the recruitment of instream wood and channel migration during and following repeated precipitation-driven high flows. Enhancing our knowledge of these geomorphological and paraglacial processes in response to high flows is important for the effective management of riverine water and ecosystem resources in rapidly changing environments.  相似文献   

中国古建筑简化分析研究   总被引：1，自引：1，他引：0  

高大峰  曹鹏男  丁新建 《地震工程与工程振动》2011,31(2):175-181

为研究中国古建筑的固有特性和抗震性能,根据西安城南门箭楼复原工程资料,采用半刚性弹簧单元来模拟实体结构的榫卯、斗拱和柱础连接,建立箭楼大木作构架的局部和整体两种有限元模型.采用Block Lanczos方法,分别进行模态分析,得出模型的前10阶频率和振型;采用瞬态分析方法,在El Centro波、Taft波和兰州人工波...  相似文献   

Genesis of the channel iron deposits (CID) of the Pilbara region,Western Australia     

R. C. Morris  E. R. Ramanaidou 《Australian Journal of Earth Sciences》2013,60(5):733-756

Miocene fluvial goethite/hematite channel iron deposits (CID) are part of the Cenozoic Detritals 2 (CzD2), of the Western Australian Pilbara region. They range from gravelly mudstones through granular rocks to intraformational pebble, cobble and rare boulder conglomerates, as infill in numerous meandering palaeochannels in a mature surface that includes Precambrian granitoids, volcanics, metasediments, BIF and ferruginous Palaeogene valley fill. In the Hamersley Province of the Pilbara, the consolidated fine gravels and subordinate interbedded conglomerates, with their leached equivalents, are a major source of export iron ore. This granular ore typically comprises pedogenically derived pelletoids comprising hematite nuclei and goethite cortices (ooids and lesser pisoids), with abundant coarser goethitised wood/charcoal fragments and goethitic peloids, minor clay, and generally minimal porous goethitic matrix, with late-stage episodic solution and partial infill by secondary goethite, silica and siderite (now oxidised) in places. Clay horizons and non-ore polymictic basal and marginal conglomerates are also present. The accretionary pedogenic pelletoids were mostly derived from stripping of a mature ferruginous but apparently well-vegetated surface, developed in the Early to Middle Miocene on a wide variety of susceptible rock types including BIF, basic intrusives and sediments. This deep ferruginisation effectively destroyed most remnants of the original rock textures producing a unique surface, very different to those that produced the underlying CzD1 (Palaeogene) and the overlying CzD3 (Pliocene – Quaternary). The peloids were derived both intraformationally from fragmentation and reworking of desiccated goethite-rich muds, and from the regolith. Tiny wood/charcoal fragments replaced in soil by goethite, and dehydrated to hematite, formed nuclei for many pelletoids. Additionally, abundant small (≤10 mm) fragments of wood/charcoal, now goethite, were probably replaced in situ within the consolidating CID. This profusion of fossil wood, both as pelletoid nuclei and as discrete fragments, suggests major episodic wild fires in heavily vegetated catchments, a point supported by the abundance of kenomagnetite – maghemite developed from goethite in the pelletoids, but less commonly in the peloids. The matrix to the heterogeneous colluvial and intraformational components is essentially goethite, primarily derived from modified chemically precipitated iron hydroxyoxides, resulting from leaching of iron-rich soils in an organic environment, together with goethitic soil-derived alluvial material. Major variations in the granular ore CID after deposition have resulted from intermittent groundwater flow in the channels causing dissolution and reprecipitation of goethite and silica, particularly in the basal CID zones, with surface weathering of eroded exposures playing a role in masking some of these effects. However, significant variations in rock types in both the general CID and the granular ore CID have also resulted from the effects of varied provenance.  相似文献