金银铂及首饰物的无损检测   总被引：1，自引：2，他引：1  

陈永君  邓赛文  梁国立 《岩矿测试》1994,(2)

使用Ｘ射线荧光光谱仪，采用透空照射、数学校正法并与比重法联用，可无损检测金、银、铂及饰物的成色，判别包、镀金饰品，较好地校正了饰物的形状、面积和光洁度的影响，不受宝石镶嵌物的限制，能够提供金、银、铂及饰物的成色和杂质元素的配比数据。用该法测定２４Ｋ及１４Ｋ值饰品的ＲＳＤ（ｎ＝９）分别为０．０１％和０．８２％，测定范围在１％～１００％之间。  相似文献   

洮坪地区花岗岩成因类型研究   总被引：1，自引：0，他引：1  

李永军 《甘肃地质》1993,(2)

造山带复杂地壳组份区的花岗岩成因类型研究倍受关注。本文从岩石化学、微量元素、稀土元素,稳定同位素等方面论述了西泰岭造山带内的沈坪地区花岗岩的成因特征,认为其成因属以S型为主并表现出大量Ⅰ型的复杂类型。文中还就其形成原因以及成因类型与构造活动演化的关系做了初步探讨。  相似文献   

A New Discovery of Early Carboniferous Gabbros in the Southern Chinese Altai: Evidence for Ridge Subduction     

WANG Zuopeng  LI Yongjun  YANG Gaoxue  ZHANG Yuling  CHAO Wendi 《《地质学报》英文版》2020,94(4):1308-1309

正Objective The Chinese Altai as a key part of the Central Asian Orogenic Belt is characterized by numerous outcrops of Paleozoic granitoids and minor mafic plutons (Fig. 1a). It is widely accepted that Devonian ridge subduction played an important role in the tectonic evolution of the Chinese Altai. However, Carboniferous magmatism related to ridge subduction has received little attention. Moreover,  相似文献   

Expression of nitric oxide synthase in the developing eye of Zebrafish<Emphasis Type="Italic">Danio rerio</Emphasis>     

王勇军  张士璀 《中国海洋湖沼学报》2004,22(4):399-402

Expression of nitric oxide synthase (NOS) in the developing eye of zebrafish was studied by NADPH-diaphorase staining technique. NOS activity was frst observed in the optic primordium and the lens placode at 5-somite stage, and remained basically unchanged up to the prim-5 stage. Upon hatching, NOS activity was nearly equally detected in the gangalion cell layer and the photoreceptor layer in the developing retina. However, it began declining in the inner plexiform layer and the inner nuclear layer at this stage. NOS activity disappeared in the lens although the anterior lens epithelium was strongly stained. Two days after hatching, NOS activity was still strong in the photoreceptor layer, but decreased markedly in the gangalion cell layer, the inner plexiform layer and the inner nuclear layer with the retinal patterning. These suggested that nitric oxide (NO), the product of NOS, is not only involved in the modulation of patterning and differentiation of the retinal cells but also in the regulation of proliferation, and differentiation of the lens fibrocytes.  相似文献   

Mesozoic granitic magmatism in extensional tectonics near the Mongolian border in China and its implications for crustal growth   总被引：6，自引：0，他引：6  

Tao Wang  Yadong Zheng  Tianbin Li  Yongjun Gao 《Journal of Asian Earth Sciences》2004,23(5):715-729

The Yagan area of the southernmost Sino–Mongolian border is characterized by an extensional structure where a large metamorphic core complex (Yagan–Onch Hayrhan) and voluminous granitoids are exposed. New isotopic age data indicate that the granitoids, which were previously regarded as Paleozoic in age, were emplaced in early and late Mesozoic times. The early Mesozoic granitoids have 228±7 Ma U–Pb zircon age, and consist of linear mylonitic quartz monzonites and biotite monzogranites. Their chemical compositions are similar to those of potassic granites and shoshonitic series, and show an intraplate and post-collisional environment in tectonic discrimination diagrams. Their fabrics reveal that they experienced syn-emplacement extensional deformation. All these characteristics suggest that the adjustment, thinning and extensional deformation at middle to lower crustal levels might have occurred in the early Mesozoic. The late Mesozoic granitoids have a U–Pb zircon age of 135±2 Ma, and are made up of large elliptical granitic plutons. They are high-K calc-alkaline, and were forcefully emplaced in the dome extensional setting. Both the early and late Mesozoic granitoids have Nd (t) values of −2.3 to +5, in strong contrast with the negative Nd (t) values (−11) of the Precambrian host rocks. This suggests that juvenile mantle-derived components were involved in the formation of the granitoids. The similar situation is omnipresent in Central Asia. This study demonstrates that tectonic extension, magmatism and crustal growth are closely related, and that post-collisional and intraplate magmatism was probably a significant process for continental growth in the Phanerozoic.  相似文献   

济阳坳陷中生代盆地演化及其与新生代盆地叠合关系探讨   总被引：61，自引：2，他引：59  

吴智平  李伟  任拥军  林畅松 《地质学报》2003,77(2):280-286

济阳坳陷中生代盆地演化受控于欧亚构造域的板块拼接挤压和滨太平洋构造域及其郯庐断裂活动两种动力学背景。早、中三叠世,作为华北大型内陆沉积盆地的一部分,沉积了近2000 m厚的地层;晚三叠世,主要受控于扬子板块与华北板块挤压碰撞所产生的挤压应力场,处于抬升剥蚀状态,早、中三叠世沉积的地层几乎剥蚀殆尽,并开始发育多条NW向逆冲断层;早、中侏罗世是对晚三叠世挤压逆冲断层和褶皱所造成的本区地势高低起伏的一个截凸填凹、填平补齐的过程;晚侏罗世—白垩纪,受郯庐断裂左行走滑的影响,济阳坳陷区前期形成的NW向逆冲断层,发生构造反转,反向伸展,形成了一系列半地堑。控盆断层为NW向的中生代盆地,与控盆断层为NE(或NNE)向的新生代盆地里相干型叠合,可划分出中坳新拗、中坳新隆、中隆新坳、中隆新隆4种叠合单元类型,不同类型的叠合单元经历了不同的沉降史,具有不同的石油地质意义。  相似文献   

3D Building Modelling with Digital Map, Lidar Data and Video Image Sequences   总被引：1，自引：0，他引：1  

Yongjun  Zhang  Zuxun  Zhang  Jianqing  Zhang  Jun  Wu 《The Photogrammetric Record》2005,20(111):285-302

Three-dimensional (3D) reconstruction and texture mapping of buildings or other man-made objects are key aspects for 3D city landscapes. An effective coarse-to-fine approach for 3D building model generation and texture mapping based on digital photogrammetric techniques is proposed. Three video image sequences, two oblique views of building walls and one vertical view of building roofs, acquired by a digital video camera mounted on a helicopter, are used as input images. Lidar data and a coarse two-dimensional (2D) digital vector map used for car navigation are also used as information sources. Automatic aerial triangulation (AAT) suitable for a high overlap image sequence is used to give initial values of camera parameters of each image. To obtain accurate image lines, the correspondence between outlines of the building and their line features in the image sequences is determined with a coarse-to-fine strategy. A hybrid point/line bundle adjustment is used to ensure the stability and accuracy of reconstruction. Reconstructed buildings with fine textures superimposed on a digital elevation model (DEM) and ortho-image are realistically visualised. Experimental results show that the proposed approach of 3D city model generation has a promising future in many applications.  相似文献   

基于数据融合的行树与篱笆三维信息自动提取     

张永军 《武汉大学学报(信息科学版)》2005,30(11):970-974

通过融合GIS数据、DSM和CIR立体影像等不同数据源,自动提取行树与篱笆的三维信息。综合采用了影像分割、边缘提取、直线段连接与编组、DSM三维验证等手段,成功地从航空立体像对中提取出目标信息。所提取的行树与篱笆信息可以应用于GIS数据更新、土壤监测与保护、风侵蚀的危害计算等。  相似文献   

论找矿勘查的风险性和降低风险的预测性勘查战略     

刘亮明  邓吉牛  彭省临  疏志明  邵拥军  杨鸿翼 《地质通报》2005,(Z1)

找矿勘查的高风险性表现在找到可赢利矿床的成功率低和找矿发现的成本越来越高,这不仅影响了矿业经济的发展,也影响了公众对地球科学的认识。根据国际找矿勘查的一些统计资料和实例分析了造成找矿勘查高风险性的原因,提出降低风险的预测性勘查战略。区域地质背景、成矿作用的复杂性和勘查者所具有的知识、思维能力、技术手段的局限性等客观因素使找矿勘查的风险不可避免,但不少找矿勘查的失败是由勘查者在资料使用、观察、思维等方面的主观失误造成的。勘查者可以通过增加尝试的次数来获取成功,更可取的是通过提高矿床预测的准确度,以预测性勘查促找矿发现,进而降低找矿勘查的风险。  相似文献   

淮南寒武纪岩溶陷落柱发育特征及导水性分析   总被引：3，自引：0，他引：3  

刘登宪  李永军 《中国煤田地质》2006,18(1):38-40,44

1996年任楼煤矿发生的陷落柱特大突水事故，使“淮南不存在岩溶陷落柱”的认识得到了质疑。通过初步调研，在孔集矿南部的孙家大山一带发现出露于地表的岩溶陷落柱，而谢桥矿煤经三维地震勘探也探测出了发育于寒武纪灰岩中的两个岩溶陷落柱。因其岩溶陷落柱的发育层位、充填物质与华北煤田奥陶纪岩溶陷落柱构成明显的对比。导致了其水文、工程地质特征的特殊性。  相似文献