CG-6型重力仪零漂特性研究     

郝洪涛  刘少明  韦进  胡敏章 《大地测量与地球动力学》2019,39(10):1086-1090

对中国地震局地震研究所最新引进的4台CG-6型相对重力仪的零漂特性进行测试研究，结果表明，4台重力仪的静态零漂率、混合零漂率和动态零漂率均小于8 μGal/h，满足厂家给出的技术指标。在较长观测时间内，各台仪器的零漂均存在不同程度的非线性特征，因此在进行较长时间的野外观测以及后续数据处理中，不宜将零漂率作为常数进行解算和零漂改正。  相似文献   

渤、黄海生态环境模拟的参数敏感度空间差异分析     

罗辰奕  聂红涛  张海彦 《海洋学报》2019,41(8):85-96

随着海洋生态系统模型的发展，生态变量增多，众多生物过程参数量值的确定成为制约生态环境模拟的瓶颈问题，生态系统结构区域性要求模型中的生态参数具有区域差异。为探究不同海区的关键参数及参数敏感度的空间差异，本研究在渤、黄海建立了ROMS-CoSiNE物理–生物耦合的高分辨率生态系统模型，并对13种生态参数的敏感度空间分布进行分析。结果表明:南黄海中部与渤海及近岸海域的敏感度差异较大。渤海敏感度最大的参数为决定光合速率的浮游植物P-I曲线初始斜率，其次为浮游动物捕食半饱和常数和浮游动物最大捕食率。而南黄海中部敏感度最大的参数为浮游动物最大捕食率，其次为浮游植物死亡率和浮游植物P-I曲线初始斜率。结合敏感度分布及浮游植物生物量收支得出，渤海水体透明度较南黄海偏低、浮游植物生长光限制较强，是引起浮游植物P-I曲线初始斜率敏感度在渤海高于黄海的主要原因。浮游动物最大捕食率及浮游植物死亡率的敏感度空间差异，受渤、黄海浮游植物生物量差异的影响，与生态系统中的高度非线性特征有关。  相似文献   

滇西北地区近年来应力场的数值模拟研究     

武永彩  李昂  唐红涛 《大地测量与地球动力学》2018,38(12):1238-1240

建立滇西北地区三维有限元地质模型，将2009~2016年GPS速度场数据作为数值模拟的位移边界条件，模拟获取该地区的构造应力场。结果表明，在楚雄至滇西北地区整体显示张性应力区；出现由“洱源鹤庆断裂-红河断裂-程海断裂”圈起的低值张性区，区域内部张性应力明显低于外部，这种张应力低值区尤其在区域四周断裂边界处，往往是地壳断裂活动的频发区；曲江断裂北端及元谋-绿汁江断裂南端出现张性应力集中区，是今后重点关注的断裂结点。  相似文献   

An algorithm to resolve γ-rays from charged cosmic rays with DAMPE     

Zun-Lei Xu  Kai-Kai Duan  Zhao-Qiang Shen  Shi-Jun Lei  Tie-Kuang Dong  Fabio Gargano  Simone Garrappa  Dong-Ya Guo  Wei Jiang  Xiang Li  Yun-Feng Liang  Mario Nicola Mazziotta  Maria Fernanda Munoz Salinas  Meng Su  Valerio Vagelli  Qiang Yuan  Chuan Yue  Jing-Jing Zang  Ya-Peng Zhang  Yun-Long Zhang  Stephan Zimmer 《天文和天体物理学研究(英文版)》2018,(3)

The DArk Matter Particle Explorer(DAMPE),also known as Wukong in China,which was launched on 2015 December 17,is a new high energy cosmic ray and γ-ray satellite-borne observatory.One of the main scientific goals of DAMPE is to observe Ge V-Te V high energy γ-rays with accurate energy,angular and time resolution,to indirectly search for dark matter particles and for the study of high energy astrophysics. Due to the comparatively higher fluxes of charged cosmic rays with respect to γ-rays,it is challenging to identify γ-rays with sufficiently high efficiency,minimizing the amount of charged cosmic ray contamination. In this work we present a method to identify γ-rays in DAMPE data based on Monte Carlo simulations,using the powerful electromagnetic/hadronic shower discrimination provided by the calorimeter and the veto detection of charged particles provided by the plastic scintillation detector. Monte Carlo simulations show that after this selection the number of electrons and protons that contaminate the selected γ-ray events at～10 Ge V amounts to less than 1% of the selected sample.Finally,we use flight data to verify the effectiveness of the method by highlighting known γ-ray sources in the sky and by reconstructing preliminary light curves of the Geminga pulsar.  相似文献   

Fault geometrical model of Dujiangyan section in Longmenshan fault zone          下载免费PDF全文

Hu-Rong Duan  Sheng-Lei Chen  Run Li  Quan-Chao Yan 《地震科学（英文版）》2018,31(3):126-136

The focal mechanism solution on the seismic fault plane can reflect the geometric and kinematic characteristics of faults, and it is an important way to further study the fine structure of fault plane. From the focal mechanism solution of the earthquakes around the Dujiangyan fault in Longmenshan fault zone, we derived the average dip angle of Dujiangyan fault is 45.1° based on the seismic moment tensor theory. In order to refine the fault geometry structure, this paper decomposed it into multiple sub-fault planes along the length and width of the fault plane and forms a number of models A13, B13, A23 a, A23 b, A23 c, B23 a,B23 b and B23 c, then calculated the sub-fault's dip of each model. In order to clarify exactly which one of the fault models is closest to the real fault model, the fault slip was carried out for each model in turn, then compared the surface displacement of each model with GPS observations. The results show that B23 c model with high dip in shallow and small dip in deep is the best model, the lengths of each subfault of Dujiangyan fault from south to north are 33 km, 21 km and 46 km, respectively. When the depth of the fault bottom is about 11 km, the dip angles are 70.56°, 67.41° and 45.55°.When the depth of the fault bottom is about 30 km, The fault dip angles are 44.55°, 29.18° and 44.25°.  相似文献   

Variation in soil saturated hydraulic conductivity along the hillslope of collapsing granite gullies   总被引：2，自引：0，他引：2  

Xiaoqian Duan  Yusong Deng  Yu Tao  Yangbo He  Lirong Lin 《水文科学杂志》2018,63(5):803-817

Saturated hydraulic conductivity (K_s) affects the soil hydrological process and is influenced by many factors that exhibit strong spatial variations. To accurately measure K_s and its scale, spatial variability and relationship with collapsing gullies, we analysed four double-ring infiltrometer diameters in three soil layers during in situ experiments designed to measure K_s in two typical collapsing gullies (three slope sites) in Tongcheng County of China. The results showed that K_s increased with increasing inner ring diameter, but no significant difference existed between inner diameters of 30 and 40 cm. The K_s in red soil layers was higher than that in sandy soil layers, the transition layers had the lowest values. K_s also varied with slope position, gradually decreasing with distance from the gully head. The suggestion is that the spatial variation in K_s is affected not only by the intrinsic soil properties but also by the interaction with the collapsing gully.  相似文献   

城市“腾笼换鸟”产业转型升级的困境与出路——基于北京市的调查研究     

王颖  段霞  吴康 《地理科学》2020,40(5):786-792

剖析北京“腾笼换鸟”产业转型升级的现状,在针对“新鸟”进笼“老鸟”去哪问题,“老笼”空间结构合理优化问题,“老鸟”涅槃“新鸟”培育问题,“老鸟”和“新笼”承接问题的分析基础上,提出应完善京津冀产业链协作,“腾笼换鸟”拓展区域联动发展空间;东西城合并成首都特区,“腾笼换鸟”保护北京历史文化名城;切实发挥政府的职能作用,“腾笼换鸟”提升企业内在动力机制;规划建设“微中心”小城镇,“腾笼换鸟”促进北京人口有效疏解的建议。  相似文献   

中学地理科学实验的六大类型及其案例分析     

杨崝源  段玉山  姚泽阳  马倩怡  刘妍君 《地理教学》2020,(3):9-15

依据实验的根本目的,为拓展学生对地理过程的理解,体验真实的地理原理,笔者将中学地理科学实验划分为经典实验室实验、时间变化模型实验、类比实验、空间变化模型实验、物理模型实验以及计算机模型实验六大类型,并对每一类型实验进行举例分析,希望以此深化地理科学实验的理论研究、丰富地理科学实验的实践案例、培养学生的地理核心素养,为地理科学实验教学研究提供新的视角。  相似文献   

科尔沁湿草甸参考作物蒸散发模拟分析     

李霞  刘廷玺  段利民  王冠丽  童新  周亚军  杨晓君 《中国沙漠》2020,40(2):134-143

为探明气候变化下干旱半干旱地区湿草甸参考作物蒸散发(ET₀)影响因子,使用FAO 56 P-M模型对科尔沁湿草甸ET₀进行模拟,利用涡度相关系统对模型的适用性进行评价,并通过通径分析及指标敏感性分析对ET₀的影响因子进行辨识。结果表明:(1)小时尺度模拟精度最高,日尺度次之,月尺度较差,小时尺度上晴、阴、雨3种天气条件下模拟效果不同,晴天最优,阴雨天较差。(2)ET₀年内变化呈单峰曲线状,生长季明显高于非生长季,集中在3—10月,占全年89.79%。生长季典型晴天ET₀逐小时分布特征遵循倒“U”单峰型变化规律。(3)通径分析结果显示,对ET₀的通径系数以及对回归方程估测可靠程度E的总贡献均表现为VPD(饱和水汽压差) > T_min(最低气温) > R_n(冠层表面净辐射)>u₂(2 m高度风速),即VPD为影响ET₀最重要的因子;指标敏感性分析中,在去除VPD后引起的E变化最大,说明ET₀对VPD的变化最为敏感,其次为u₂、T_min和R_n。  相似文献   

基于水声环境空间中多模态深度融合模型的目标识别方法研究     

李琦  孙桂玲  黄翠  刘颉  常哲  于金花  文洪涛 《海洋技术学报》2019,38(6):35-45

随着对水下目标特性研究的深入和声学探测技术的发展,基于单模态的阵列式信息融合或基于空间信息的分布式信息融合的水下目标识别方法研究已有一定成果,但针对复杂海况导致单一物理场或单一融合层次的系统识别性能提高有限等方面影响的水下目标识别方法研究还有所不足,因此,开展基于多模态深度融合模型的水下目标识别方法研究可利用模态互补,共享信息而提升识别率。文中在国内外研究基础上,深入研究了基于到达时差法和多模态方法组合的检测方法,初步形成了基于水声环境空间中多模态深度融合模型的识别框架,开展了海洋中典型自然与人为事件的信号分析与特征提取,并在此基础上,设计新型基于海底基站的被动识别系统。该系统同步记录和由位置等组成的时间序列标记声、磁和压数据,可实现高精度、高分辨率的识别。本研究可满足未来海洋观测对高性能水下目标探测、定位和跟踪系统的迫切需要,为海洋安全监管、海洋突发事件应急响应等领域提供新的技术手段和科学参考。  相似文献