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GR-2 geologic radar is developed by China University of Mining Technology (Beijing), owning the Intellectual Property Right. The touch screen of Radar mainframe system improves the efficiency in field. System impulse emission frequency is 200KHz, so its efficiency is high but the cost low. GR-2 geologic radar can detect continuously, displaying real time two-dimension image and Chinese menu.  相似文献   

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《震灾防御技术》2021,16(2):429-429
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重庆市巫山县望霞危岩是长江三峡黄金水道巫山段左岸的一处典型重大危岩体,2010年雨季出现明显变形,随后转入应急监测,并依据监测成果两次成功预警。本文基于地质分析和监测成果,研究望霞W2-2危岩体变形-演化的动力学过程,发现持续降雨是崩滑灾害发生的直接诱发因素。雨水渗入浸泡使泥岩软基强度降低,塑流变形加剧,加大了危岩的下部变形程度,使上覆砂岩层沿接触底面出现拉裂。同时水体作用造成危岩中节理、裂隙极其发育。W2-2危岩体变形破坏演化过程可分为前期累积变形、匀速变形、加速变形和临界加速变形四个阶段,其中加速变形点和临界加速变形点具有很好的预警指示意义,加速点可视为岩体稳定与不稳定破坏的分界点。  相似文献   

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Abstract

Two distributions of the α-effect in a sphere are considered. The inviscid limit is approached both by direct numerical solution and by solution of a simpler nonlinear eigenvalue problem deriving from asymptotic boundary layer analysis for the case of stress-free boundaries. The inviscid limit in both cases is dominated by the need to satisfy the Taylor constraint which states that the integral of the Lorentz force over cylindrical (geostrophic) contours in a homogeneous fluid must tend to zero. For a small supercritical range in α, this condition can only be met by magnetic fields which vanish as the viscosity goes to zero. In this range, the agreement of the two approaches is excellent. In a portion of this range, the method of finite amplitude perturbation expansion is useful, and serves as a guide for understanding the numerical results. For larger α, evidence from the nonlinear eigenvalue problem suggests both that the Taylor state exists, and that the transition from small to large amplitude can require a finite amplitude (oscillatory) instability in accord with the findings of Soward and Jones (1983). However, solutions of the full equations have not been found which are independent of viscosity at larger values of α.  相似文献   

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从地球重力场基本理论出发,导出了大地水准面上局部切平面坐标下的重力梯度矢量水平分量和垂直分量的计算公式,利用由多颗测高卫星联合反演的2'×2'海洋重力异常和垂线偏差资料,计算了西太平洋海域2'×2'重力梯度矢量水平分量和垂直分量.将计算的重力垂直梯度和现有资料进行比较,标准差为9.99E,并对重力梯度的空间分布特征进行了初步分析.  相似文献   

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1 Introduction As one of the most important greenhouse gases, atmospheric carbon dioxide (CO2) has increased in concentration rapidly since preindustrial times[1―4] and significantly contributes to the climate change[5] caused by anthropogenic emissions. Documentation of the global carbon cycle has been critical for under-standing the causative relationships between green-house gases and climate change. For example, the CO2 level in the atmosphere has been monitored at many sites worldwide …  相似文献   

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《湖泊科学》2021,33(2)
升金湖 (30°21′′N, 117°05′E) 位于长江下游、安徽省沿江,为浅水湖泊湿地,2015 年入选《国际重要 湿地名录》(摄影:王继明)  相似文献   

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Abstract

An idealised α2ω-dynamo is considered in which the α-effect is prescribed. The additional ω-effect results from a geostrophic motion whose magnitude is determined indirectly by the Lorentz forces and Ekman suction at the boundary. As the strength of the α-effect is increased, a critical value α? c is reached at which dynamo activity sets in; α? c is determined by the solution of the kinematic α2-dynamo problem. In the neighbourhood of the critical value of α? the magnetic field is weak of order E 1/4(μηρω)½ due to the control of Ekman suction; E(?1) is the Ekman number. At certain values of α?, viscosity independent solutions are found satisfying Taylor's constraint. They are identified by the bifurcation of a nonlinear eigenvalue problem. Dimensional arguments indicate that following this second bifurcation the magnetic field is strong of order (μηρω)½. The nature of the transition between the kinematic linear theory and the Taylor state is investigated for various distributions of the α-effect. The character of the transition is found to be strongly model dependent.  相似文献   

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断层气CO2测定法具快速、简便、价廉、可靠和有效的特点,介绍了CO2观测仪器的安装方法以及CO2快速测定的方法,认为,在城市中受到场地,观测环境等条件的影响,建立CO2测试点是较合理的.  相似文献   

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介绍了CZM—2型恒流器自动充电器的主要特性、电路工作原理、安装和调试方法。  相似文献   

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地震预报与地震危险性评估是本届会议的第一专题,也是最大的一个专题,共收到交流论文和张贴报告60篇,约占全部专题文章总数的1/3.这60篇文章中,包括印度15篇,中国13篇,俄罗斯8篇,亚美尼亚6篇,法国、新西兰、墨西哥、埃及、伊朗等国家的地震学者也提交了文章.在2天的学术交流中,共有30篇文章口头交流或张贴.这些文章揭示了从地震预测预报到地震社会学的诸多层次的问题.  相似文献   

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《湖泊科学》2022,34(2)
白洋淀,属海河中游大清河流域,位于河北省雄安新区,是华北平原最大的淡水湖.水域面积366 km2,计有大小淀泊143个,淀域内沟壕纵横,村落星罗棋布,水面苇田相间(摄影:尹德超).  相似文献   

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Abstract

The modal α2-dynamo of Hollerbach and Ierley (1991) is extended to include both parities, dipolar and quadrupolar. Two choices of α are considered. As before, the solutions approach the Taylor state, and the subsequent equilibration is independent of the viscosity in the asymptotic limit. The first choice of α yields stable steady-state pure-parity solutions of either type, and may yield some insight into the question of parity selection. The second choice of α yields rather complex time-dependent mixed-parity solutions, and demonstrates the extent to which parity coupling can affect the evolution of time-dependent solutions.  相似文献   

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12.佛爷沟卵石墙震倒 14.土坯窑震塌13 土坯窑震塌、室内顶券有纵向裂缝18.山顶塌方,压塌、埋掉土窑20.北辛窑大队集体修建的抗震棚,东面有大队办的夜校和林格尔震区所见(2)  相似文献   

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《湖泊科学》2022,34(2)
湖 泊 科 学(Hupo Kexue) 2022年第34卷第2期3月6日 目次 综述 湖泊蓝藻水华防控方法综述(349) 史小丽,杨瑾晟,陈开宁,张民,阳振,于洋 噬藻体对蓝藻种群密度的调控及其对水体中物质循环的影响(376) 张奕妍,黄兰兰,王夕予,丁士明,刘子鹤,童银栋 研究论文 ——富营养化与水华防控 基于Sentinel-3 OLCI影像的巢湖藻蓝素浓度年内动态遥感监测(391) 汪志成,王杰,晏实江,崔玉环,王行行 南亚热带特大型水库浮游植物群落特征及其与环境因子的关系:以新丰江水库为例(404) 张辉,彭宇琼,邹贤妮,张婷婷,巫楚,乔永民,杨洪允 钱塘江干流夏季浮游植物群落结构特征及其对水文气象的响应(418) 张萍,国超旋,俞洁,权秋梅,姚建良,王吉毅,叶小锐,朱梦圆,孙起亮,朱广伟 鄱阳湖流域柘林水库秋季浮游植物群落结构及其构建过程驱动机制(433) 陈康,孟子豪,李学梅,朱挺兵,胡飞飞,刘璐,朱永久,范春林,杨德国 城市中小河道沉水植物盖度和生物量计算方法——基于上海市的调查分析(445) 张群,刘家霖,朱义,张春松,宋晴,崔心红 ——生物地球化学与水环境保护 太湖沿岸区浅层底泥重金属污染分析及生态风险评价(455) 陆志华,蔡梅,王元元,钱旭,潘明祥 水库环保疏浚及板框脱水工程中余水水质及变化规律(468) 朱伟,许小格,侯豪,程林,李岳鸿,林小蔚,吴勇 新疆艾比湖流域河湖水质变化(20052020年)(478) 张飞,王维维,辛红云,郝晋新,刘长江,段潘 白洋淀湿地表层土壤主要环境元素分布特征及来源(496) 刘雪松,王雨山,王旭清,尹德超 白洋淀湿地不同植物群落区表层沉积物碳氮磷化学计量特征(506) 尹德超,王雨山,祁晓凡,安永会,王旭清,徐蓉桢 基于SWAT模型的典型农业小流域氮污染时空分布特征及关键源解析(517) 王慧勇,遆超普,王良杰,董磊,夏永秋,颜晓元 鄱阳湖水体溶解无机碳的季节变化、输送及其来源(528) 李艳红,葛刚,胡春华 白洋淀春季沉积物好氧反硝化菌群落结构特征及对溶解性有机物的响应(538) 陈召莹,张甜娜,张紫薇,周石磊,董宛佳,崔建升,罗晓 亚高山湖泊天才湖周边土壤腐殖酸的光降解研究(553) 安世林,罗春燕,陈煜,杜瑛珣 ——淡水生态与生物多样性保育 网围拆除后东太湖鱼类功能群时空变化及影响因子(569) 谷先坤,刘燕山,唐晟凯,李大命,张彤晴,曾庆飞,毛志刚,陈辉辉,谷孝鸿 秀丽白虾(Exopalaemon modestus)对亚热带湖库春夏季水体营养水平和浮游生物群落的影响—— 基于微宇宙模拟实验(582) 宁晓雨,张磊,陈坤全,韩财安,李启升,李宽意,何虎,赵璧影 基于脂肪酸生物标志物分析南京市及其周边不同营养水平湖库的浮游动物碳源(590) 马静静,李廷真,李宽意,苏雅玲,刘正文 ——流域水文与水资源安全 鄱阳湖环湖灌区枯季缺水量分析及对策建议(601) 李振旗,程和琴,李纪人,向诗月,滕立志 三峡水库蓄水前后长江中下游流量频率分布特征及其对洪水造床作用的影响(616) 周炜兴,孙昭华,周坤,李芷晴,陈立 控制反调节水库协同生态调度的优化策略:以三峡葛洲坝梯级水库为例(630) 李游坤,林俊强,秦鑫,刘毅,任玉峰,张晓光 基于频谱分析的水体波浪紊动流速分离方法(643) 段雨新,张占飞,张英豪 半干旱地区洪水模拟效果差异性分析及影响因子响应评估(652) 刘玉环,李致家,刘志雨,罗赟,霍文博 过坝下泄水流中温室气体排放速率的数值模拟(664) 黄菊萍,欧洋铭,李然,冯镜洁,李哲 ——湖泊沉积与环境变化 太湖流域长荡湖近百年生态环境演变过程(675) 刘维淦,林琪,张科,沈吉 黑龙江省连环湖孢粉记录揭示的约220年的环境变化与人类活动(684) 王小丽,肖海丰,肖霞云 自然解读 神奇的球状冰(冰球、冰蛋)(695) 解飞,卢鹏,程斌,杨倩,李志军  相似文献   

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