In situ LA-ICP-MS zircon U-Pb age of ultrahigh-pressure eclogites in the Yukahe area,northern Qaidam Basin

Zircon grains were selected from two types of ultrahigh-pressure (UHP) eclogites, coarse-grained phengite eclogite and fine-grained massive eclogite, in the Yukahe area, the western part of the North Qaidam UHP metamorphic belt. Most zircon grains show typical metamorphic origin with residual cores in some irregular grains and sector, planar or misty internal textures on the cathodoluminescence (CL) images. The contents of REE and HREE of the core parts of grains range from 173 to 1680 μg/g and 170 to 1634 μg/g, respectively, in phengite eclogite, and from 37 to 2640 μg/g and 25.7 to 1824 μg/g, respectively, in massive eclogite. The core parts exhibit HREE-enriched patterns, representing the residual zircons of protolith of the Yukahe eclogite. The contents of REE and HREE of the rim parts and the grains free of residual cores are much lower than those for the core parts. They vary from 13.1 to 89.5 μg/g and 12.5 to 85.7 μg/g, respectively, in phengite eclogite, and from 9.92 to 45.8 μg/g and 9.18 to 43.8 μg/g, respectively, in massive eclogite. Negative Eu anomalies and Th/U ratios decrease from core to rim. Positive Eu anomalies are shown in some grains. These indicate that the presence of garnet and the absence of plagioclase in the peak metamorphic mineral assemblage, and the zircons formed under eclogite facies conditions. LA-ICP-MS zircon U-Pb age data indicate that phengite eclogite and massive eclogite have similar metamorphic age of 436±3Ma and 431±4Ma in the early Paleozoic and magmatic protolith age of 783–793 Ma and 748–759 Ma in the Neo-proterozoic. The weighted mean age of the metamorphic ages (434±2 Ma) may represent the UHP metamorphic age of the Yukahe eclogites. The metamorphic age is well consistent with their direct country rocks of gneisses (431±3 Ma and 432±19 Ma) and coesite-bearing pelitic schist in the Yematan UHP eclogite section (423–440 Ma). These age data together with field observation and lithology, allow us to conclude that the Yukahe eclogites were Neo-proterozoic igneous rocks and may have experienced subduction and UHP metamorphism with continental crust at deep mantle during the early Paleozoic, therefore the metamorphic age of 434±2 Ma of the Yukahe eclogites probably represents the continental deep subduction time in this area.

     

光栅栅距检测与线阵CCD细分技术研究

利用线阵CCD分辨率高、像素均匀等特点对光栅莫尔条纹进行细分是目前广泛采用的一种新技术。由于CCD具有自扫描能力，能将光强随空间分布的莫尔条纹信号转换成随时间变化的电信号，从而可以对光栅刻线的像的移动进行精确定位和直接数字化，改变传统莫尔条纹位相细分方法，实现对光栅栅距进行高倍数的细分。     

基于模糊Hopfield神经网络的大气降水粒子分类

提出基于模糊Hopfield神经网络的大气降水粒子分类,它是通过计算样本间的模糊关系的相似程度,再加上Hopfield网络所特有的高稳定性,对大气降水粒子进行分类.通过对各降水粒子所对应雷达回波数据的分析,验证了方法的可行性.     

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Nodes and Field of Tourist Origins to Ancient Village——A Case Study of Huangcheng Village in Shanxi Province of China

Based on Hagget's theory of spatial structure,researches on the nodes and field of tourist origins to Huang-cheng Village in Shanxi Province of China have been explored.Nodal hierarchy structure of tourist origins is analyzed with cluster analysis and the gravity model.And field of tourist origins is analyzed with attraction radius index(R)and geography concentration index(G).In the field analysis,R and G of Huangcheng Village are compared with Xidi Village that is a world heritage located in Huangshan City of Anhui Province in China.According to comparison of loca-tions of two areas,influential factors for field area of Huangcheng Village are identified.It is concluded that:1)cluster analysis and gravity model can be complementary methods to each other for nodal hierarchy structure analysis of tour-ist origins;and 2)as far as location is concerned,the weak intensity effect of tourism resources in the tourist region is a major cause for explaining why tourist origins to Huangcheng Village are mainly its neighboring areas.Moreover,it is suggested that the regional effect of tourist resources should be regarded as a component of destination attractiveness when applying gravity model.     

一种新型数字水准仪室内检定装置

数字化精密水准测量仪器在水准及形变测量领域中起着极其重要的作用,而对数字水准仪的计量检定工作是使其正常运行的前提,针对其检定项目室内化的难题,介绍了一种国产新型数字水准仪的室内检定装置.     

干支回推-天文年代学的一种新方法

“干支回推法”是针对中国历史时期所特有的干支材料而设计的新天文年代学方法．以一组假设的材料为例,系统地给出了该方法的完整求解过程．指出该方法的优势在于准确高效,能有效地处理某些年代学难题．此外,除材料的公历日期外还能将当时的历法细节一同迭代解出．     

多普勒天气雷达高速数据采集系统的设计

多普勒天气雷达需要一个高速数据采集系统,以实现大量的基数据到微机中的实时传输,同时将控制命令传送到雷达处理器中。利用FPGA器件zynq-7000具有片上系统(SOC)的结构特点,构建一个具有高速传输功能的典型信号处理系统。采用千兆以太网芯片88E1518作为数据传输接口,以内嵌的Cortex-A9处理器作为接口的配置和控制部件,通过裁剪和重构Linux操作系统运行由C语言开发的软件应用系统程序代码,实现千兆以太网接口以及数据传输与命令交互功能。有限次实验和测试结果表明,采集系统容易达到640Mbps的数据传输速率,满足雷达数据采集的需求,未出现性能不稳定现象。     

性类固醇激素E2、MT 对尼罗罗非鱼(Oreochromis niloticus)雌、雄生长差异的影响

性类固醇激素对动物生长有一定的影响, 但其对鱼类雌、雄生长差异的影响机理尚不清楚。 为进一步了解动物雌雄生长差异的内在原因, 本文通过在体注射和荧光定量PCR 方法, 比较了性类 固醇激素(E₂、MT)对尼罗罗非鱼雌鱼和雄鱼的生长及对垂体GH、肝脏GHR1、IGF-I mRNA 表达的 影响。结果表明: 性类固醇激素E₂ 和MT 对尼罗罗非鱼的生长及生长轴相关基因的表达均有显著的 影响, 并且这种影响存在明显的性别二态性。E₂ 明显促进雌鱼的生长但不显著影响雄鱼的生长, MT 显著促进雄鱼和雌鱼的生长; E₂ 可使雌鱼垂体GH 和肝脏GHR1 、IGF-I 的mRNA 水平显著升高 (P<0.05), 但降低雄鱼垂体GH和肝脏GHR1的mRNA表达; MT 显著提高雄鱼垂体GH和肝脏GHR1、 IGF-I mRNA 水平(P<0.05), 但降低雌鱼垂体GH 的mRNA 表达, 促进雌鱼肝脏GHR1 mRNA 的表达, 但对雄鱼肝脏GHR1 的促进作用明显大于雌鱼(P<0.05).上述结果表明, 性类固醇激素对不同性别尼 罗罗非鱼的生长及生长轴相关基因的mRNA 表达有不同的影响, 表现出明显的性别二态性, 提示不 同性别鱼体内性类固醇激素水平的不同可能是导致尼罗罗非鱼雌雄生长二态性的另一内在原因。