Characteristics of deuterium excess parameters for geothermal water in Beijing

This study investigates the characteristics of geothermal water in 10 geothermal fields in Beijing. The relationships between the deuterium excess parameter (d) and temperature, depth, age of geothermal groundwater, groundwater flow field, and Eh were investigated using geothermal groundwater samples. Results showed that (1) the average d value of geothermal water is 5.4, whereas that of the groundwater in normal temperature is 6.04. The differences are induced by the oxygen isotope exchange during the water–rock interaction, which may be more easily completed in geothermal water than in cold groundwater. (2) The d value increases remarkably with the age of the geothermal groundwater. The d value increases from 11.2 to 14.6 when the age of the geothermal water is 12,760 ± 130 a and 38,960 ± 630 a, respectively. Moreover, the isotope heat exchange for composition of the hydrogen and oxygen isotopes in the geothermal groundwater proceeds sufficiently with time. (3) The d value decreases from 5.72 to 3.03 when the depth increases from 125.13 to 3221 m. Generally, in the same area, the d value decreases with depth because the temperature is increasing. (4) The d value of the groundwater gradually reduces from the northern recharge area to the southern discharge area. The average d value is 7.31 in the northern recharge area and 5.68 in the middle Beijing Depression, whereas the d value in the southern area of Fengheying is ?9.20. The larger difference in d values between the recharge and discharge areas is due to the slower velocity of underwater flow, which induces longer time for oxygen exchange. (5) The relationship between the d and Eh is complex. When Eh is <200 mV, the d value of the geothermal water decreases with the decrease in Eh. When Eh is higher than 200 mV, the d value increases slightly with the decrease in Eh. The study of the characteristics of deuterium excess parameters for geothermal water could provide a scientific isotopic evidence for assessment and exploitation measures in geothermal groundwater systems.     

雷电监测预警系统的原理及应用

本文讨论了有关雷电的基本知识，列举了目前存在的各种雷电定位方法，分析了雷电定位的几个过程。对近期引进VAISALA公司的SAFIR3000型雷电监测预警系统采用的探测原理做了分析，并总结了这套探测系统采用的VHF干涉测量原理特点及不足之处。     

Characteristics of seismic activity before the MS8.0 Wenchuan earthquake

The characteristics of spatio-temporal seismicity evolution before the Wenchuan earthquake are studied. The results mainly involve in the trend abnormal features and its relation to the Wenchuan earthquake. The western Chinese mainland and its adjacent area has been in the seismically active period since 2001, while the seismic activity shows the obvious quiescence of M≥?7.0, M≥?6.0 and M?≥5.0 earthquakes in Chinese mainland. A quiescence area with M?≥7.0 has been formed in the middle of the North-South seismic zone since 1988, and the Wenchuan earthquake occurred just within this area. There are a background seismicity gap of M?≥5.0 earthquakes and a seismogenic gap of M_L?≥4.0 earthquakes in the area of Longmenshan fault zone and its vicinity prior to the Wenchuan earthquake. The seismic activity obviously strengthened and a doughnut-shape pattern of M?≥4.6 earthquakes is formed in the middle and southern part of the North-South seismic zone after the 2003 Dayao, Yunnan, earthquake. Sichuan and its vicinity in the middle of the doughnut-shape pattern show abnormal quiescence. At the same time, the seismicity of earthquake swarms is significant and shows heterogeneity in the temporal and spatial process. A swarm gap appears in the M4.6 seismically quiet area, and the Wenchuan earthquake occurred just on the margin of the gap. In addition, in the short term before the Wenchuan earthquake, the quiescence of earthquake with M_L≥?4.0 appears in Qinghai-Tibet block and a seismic belt of M_L?≥3.0 earthquakes, with NW striking and oblique with Longmenshan fault zone, is formed.     

A primary study of the correlation between the net air-sea heat flux and the interannual variation of western North Pacific tropical cyclone track and intensity

A singular value decomposition (SVD) analysis is carried out to reveal the relationship between the interannual variation of track and intensity of the western North Pacific tropical cyclones (WNPTCs) in the tropical cyclone (TC) active season (July-November) and the global net air-sea heat flux (Q net ) in the preceding season (April-June). For this purpose, a tropical cyclone track and intensity function (TIF) is defined by a combination of accumulated cyclone energy (ACE) index and a cyclone track densit...     

后方交会法配合可编程计算器在测量放线中的应用

介绍了后方交会及支导线的计算方法，探讨了Casio Fx4500计算器程序的编制，说明后方交会法配合可编程计算程序在道路施工及其它测量放线过程中不仅克服了其路基不平等许多不便之处，而且大大提高了测量放线的速度和精度，值得推广应用。     

陆海统筹背景下河口水生态环境整治修复协同机制研究

为促进我国生态环境治理和生态文明建设,文章分析我国河口水生态环境整治修复在法律规范、技术标准、技术手段、监测体系以及主体和资金等方面的现状和存在的问题,针对完善河口水生态环境整治修复协同机制提出建议。研究结果表明：在陆海统筹背景下构建河口水生态环境整治修复协同机制,应完善基本法顶层设计,加强单行法具体指导;建立协商、合...     

无人化时代反水雷装备体系构想

根据我国海洋方向面临的战略安全环境、建设“海上丝绸之路”的要求,我国的反水雷作战范围将延伸到第一岛链以外的海域,反水雷任务除了传统的近岸/ 近海反水雷任务,还增加了海峡反水雷、交通线反水雷以及海外基地反水雷等任务。 为了满足我国反水雷作战需求,结合国际上反水雷技术装备发展方向,用信息化改造、无人化拓展现有反水雷装备,构建无人化时代反水雷装备体系,形成能够在近岸、近海、中远海实施快速、安全、高效的反水雷作战能力。     

九寨沟M_S7.0地震的前兆异常时空演化特征及其分析

以2017年8月8日九寨沟MS7.0地震震中为中心,对震前不同震中距前兆异常的时空演化过程进行分析。研究表明,震中距100km范围内无前兆异常,前兆异常主要分布在震中距100～500km范围内。震前2年新增前兆异常开始逐渐增多;不同震中距范围内的新增异常测项所占比例在震前1.5年左右达到最大,在震前又降低。在震中距300km范围内的异常测项所占比例相对较高。前兆异常时空演化过程存在3个不同的变化阶段,即α阶段(前兆异常的早期阶段,包括α_1和α_2,震前1000天以上)的异常主要分布在震中东北方向和西南方向,异常具有向外扩展的特征;β阶段(前兆异常的中期阶段,震前500～1000天)的异常表现为大范围出现异常;γ阶段(前兆异常的短期阶段,包括γ_1和γ_2,震前500天内)的异常分布在震中的东北方向,表现为远源区的异常向震中收缩过程(γ_1)和近源区的异常向外扩展的过程(γ_2)。通过与其他震例对比分析发现,前兆异常的3个阶段现象可能是大震前的共性特征,大震前前兆异常的显著增加对发震时间的预测具有一定的指示意义。     

地震时空丛集程度的度量及震前异常特征初探

从Ｍｏｒｉｓｈｉｔａ空间丛集度出发，定义出其时间丛集度的表达式，并计算了几次大震前空间丛集度Ｊｓ和时间丛集度Ｊｔ的时间扫描曲线。从计算结果分析，无论是空间丛集度Ｊｓ还是时间丛集度Ｊｔ在大震发生前大都会出现高值异常。将Ｊｓ和Ｊｔ做了对比，从而对Ｍｏｒｉｓｈｉｔａ指数的含义进行了探讨，分析了各自的优缺点。结果表明，Ｊｓ和Ｊｔ可以做为一项地震活动性指标引入到地震预报中来     

山西中南部地区地壳深部地球物理场异常与地震

对山西中南部地区的地壳结构、地球物理场异常和地震活动性进行了综合研究,结果发现:临汾北部和太原南部的灵石、介休一带,仍存在发生中强地震的深部构造背景,今后应给予足够重视．