Google Earth Engine平台支持下的赣南柑橘果园遥感提取研究

赣南地区是中国柑橘主产区,柑橘种植产业经数十年发展已具较大规模。本文利用Google Earth Engine平台,使用2140景Landsat影像进行像元级融合,重构目标年份季节最小云量影像集,构建多维分类特征集,利用随机森林分类算法,实现了1990、1995、2000、2005、2010和2016年赣南柑橘果园的分布制图。结果表明：利用Google Earth Engine平台可实现大量遥感影像数据的高效处理;最小云量影像合成方法能够有效解决多云多雨地区高质量光学影像获取困难的问题;以最小云量影像合成构建的数据集,使用随机森林分类算法能够有效提取赣南柑橘果园,分类平均总体精度和Kappa系数分别为93.15%和0.90,分类效果良好;赣南柑橘果园面积由1990年9.77 km²扩大为2016年2200.34 km²,2005年以后呈大规模扩张趋势,果园分布由零星分布,逐步形成连片化的聚集分布特点,柑橘果园用地的主要来源为林地、灌丛和耕地。     

Change of ancient hydrology net in Northeast China Plain

Comparing with lithofacies palaeogeography of several great plains, the authors analyzed four great plains in Quaternary diastrophism, the sedimentary facies, sedimentary environment and their evolution from the independent embryonic and river system of ancient Heilongjiang finally to the Halar highland, Songnen Plain, Sanjiang Plain, the Xingkai Lake Plain and various river systems, collected the unification outside the system of Heilongjiang River to release into the sea, south ancient Xialiao River finally piracy Dongliao River, Xialiao River had released into the sea the ancient water law vicissitude and the evolved rule.     

关于时间本质的研究

本文简要介绍人类认识时间的历史进程,指出目前在哲学和自然科学两个领域对时间性质的研究仍然存在着需要进一步探索的问题。这些问题主要有：1．时间有没有起点？2．时间是无限的还是有限的？3．关于时间的方向性;4．时间可不可以量子化？     

A VLBI Study of Compact Steep Spectrum Sources 3C43, 3C48 and 3C454

We used the VLBA(NRAO, USA) and made VLBI observations towards the compact steep spectrum sources 3C43, 3C48 and 3C454 at the central frequency 1.6 GHz, and obtained their total flux density maps and information on the structures of their components. By comparison with the previous data, we analyzed the variations of their flux densities as well as the displacements of their components. It is found that the total flux density of the source 3C43, as well as the flux densities and relative positions of its components are quite stable in 14 years. For the source 3C454, the total flux density and the flux densities of its components are also relatively stable, but two of the components moved away from the central core with superluminal velocities of 21.6c and 17.7c. Fitted to their flux densities at 4 L-band frequencies, the spectral indexes of the sources 3C43 and 3C454 were obtained to be 0.63 and 0.86, respectively, in good agreement with previous results, and consistent with the definition of α ≥0.5 for compact steep spectrum sources.     

磁致伸缩微位移驱动器性能测试分析

介绍了磁致伸缩微位移驱动器的工作原理,分析了检测方法,设计了使用双频激光干涉仪作为测量基准的测试平台;对该驱动器的位移的输出特性进行了测试,通过拟合处理对测试结果进行数据分析,可提高超磁致伸缩微位移驱动器的线性度和控制精度,使得驱动器性能改善.基于磁致伸缩效应原理研制的微位移驱动器,具有线性好、分辨率高、精度高等优点,经测试,达到了设定的参数指标要求.     

NTSCGNSS-2型GPS/GLONASS时间传递接收机的性能测试

与全球定位系统(GPS)不同的是全球导航卫星系统(GLONASS)的P码未加密,向所有用户开放,更有利于时间比对.结合国内外需求,中国科学院国家授时中心研制了GPS/GLONASS时间传递接收机NTSCGNSS-2.介绍了GLONASS信号特点和对NTSCGNSS-2的初步测试结果.     

施密特巡天星表的现状和展望

扼要介绍了施密特巡天底片及基于此编制而成的施密特巡天星表的发展历程,并详细介绍了GSC2.3和USNO-B1.0的情况.分析研究了这类星表存在的问题和原因所在,并提出了一个新的计划:利用现有施密特底片资料并增加新的第3期观测,编制一个具有绝对自行、多色测光、系统均匀的高密度全天星表以满足各方面的需要.     

辽东湾葵花岛构造区浅层气分布特征、成因探讨及工程影响

揭示了葵花岛构造区浅层气规模小、埋藏浅、分布散、压力低、储层松散等分布特点,根据沉积环境和地质特征,推测浅层气为生物甲烷气,但并不完全排除是热生甲烷次生气藏的可能性,探讨了浅层气潜在的工程危害并提出相应防治措施,为今后海洋工程建设提供科学依据。     

安徽巢湖凤凰山栖霞组臭灰岩段黄铁矿结核的地球化学

沉积黄铁矿的地球化学是认识重金属汇、矿床金属来源、古海洋化学及环境条件的重要途径。巢湖北郊凤凰山上石炭统黄龙组至下二叠统栖霞组臭灰岩段揭露良好,臭灰岩中黄铁矿结核普遍,集中产出于碳质页岩上2~3 m的沥青质灰岩中,其地球化学特征及成因不清。为查明黄铁矿结核的地球化学特征,分析臭灰岩段的沉积环境,推断早二叠世早期古环境演化,厘清碎屑岩段与臭灰岩的关系,从该剖面采集10个黄铁矿结核和灰岩样品,采用偏光显微镜、X射线荧光光谱仪和电感耦合等离子体质谱仪分析测试其矿物成分和主微量元素组成。结果表明：凤凰山下二叠统栖霞组臭灰岩段下部普遍发育的黄铁矿结核呈块状和微晶粒状,与灰岩界线清晰,并未切割或破坏有机质纹层,为成岩孔隙水交代生物而成。臭灰岩中SO3和Fe2O3显著富集,分别与高含量有机质和与下伏碎屑岩段一致的陆源供应有关。与上陆壳相比,臭灰岩中Se、Mo和Cd富集,黄铁矿结核中Cr、Ni、As、Se、Mo、Cd、Sb和Hg富集。碎屑岩- 臭灰岩的岩性组合、黄铁矿结核的分布范围及其主微量元素地球化学特征均表明臭灰岩和黄铁矿结核沉积于受部分陆源物质影响的稳定大陆边缘缺氧强还原海相环境。     

Geochronology and Geochemistry of Ore-related Granitoids in the Giant Gariatong Rb Deposit, Tibet and Implications for Rb Metallogeny in China

Rubidium (Rb) deposits mostly occur in the South China and Central Asia orogenic belts and are often closely associated with highly differentiated granites. This study investigates a newly-discovered giant Rb deposit at Gariatong in the Central Lhasa terrane in Tibet. Detailed field studies and logging data revealed that the Rb mineralization mainly occurs in monzogranite and is related to greisenization. LA-ICP-MS U-Pb dating of zircon yielded ages of 19.1 ± 0.2 Ma and 19.0 ± 0.2 Ma for greisenized monzogranite and fresh monzogranite, respectively. The monzogranites are characterized as strongly peraluminous, with high contents of SiO2, Al2O3, K2O and Na2O as well as a high differentiation index. They are enriched in light rare earth and large ion lithophile elements with signi?cant negative Eu anomalies and depleted high field-strength elements. Petrological and geochemical features of these ore-related monzogranites suggest that they are highly fractionated S-type granites, derived from remelting of crustal materials in a post-collisional setting. The geochemistry of zircon and apatite points to a low oxygen fugacity of the ore-related monzogranite during the magma’s evolution. The discovery of the Gariatong Rb deposit suggests that the Central Lhasa terrane may be an important region for rare metal mineralization.