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901.
针对测绘外业作业环境恶劣、安全风险较高等现状,结合外业车辆和人员安全监管工作的实际需要,提出了一种基于北斗二代系统的移动智能安全监管系统,文中给出了系统的设计思路、系统的架构设计,并介绍了系统的关键技术。系统通过北斗二代终端设备实现在Android智能手机上对车辆和人员进行实时监管,建立了按院管车、以车管人的外业生产安全监管机制,实现了车辆与人员管理的实时化、可控化、智能化,为人财物的安全管理提供了行之有效的科技支撑手段。  相似文献   
902.
针对当前水行政执法管理的需求及系统现状,以面向对象的设计方法,恪守"高内聚、紧耦合"的设计原则,采用组件化、参数化、模式化、集成化等先进构造思想,充分利用Silverlight、WebGIS、工作流、数据库、规则库、物联网、GPS等技术,采用成熟的组件和模块,构建灵活、健壮、高效、稳定的水行政移动执法系统,为提升水行政执法效率和质量提供了有力的技术和平台支撑。  相似文献   
903.
We selected 457 blazars(193 flat spectrum radio quasars, 61 lowsynchrotron peaked blazars, 69 intermediate-synchrotron peaked blazars and 134high-synchrotron peaked blazars) from the second Fermi-LAT catalog(2FGL) of γ-ray sources, which have X-ray observations. We calculated the lower limits for their Doppler factors, δγ, and compared the lower limits with the available Doppler factors and the apparent superluminal velocities in the literature.  相似文献   
904.
利用GPS流动观测站200 km范围内站点的连续观测时间序列提高GPS流动观测的定位精度,探讨GPS流动观测结果的可靠性。结果表明:1)流动观测站点速度测量值与连续观测结果差值标准差在改正后平均减小37.97%;2)TAIN、CASH两个站点的同址观测实测值改正后偏离值平均减小38.9%。  相似文献   
905.
山东金青顶金矿床Ⅱ号矿体成矿特征   总被引:1,自引:0,他引:1       下载免费PDF全文
金青顶金矿床Ⅱ号矿体位于胶东隆起南缘,牟平乳山金成矿带中部,是目前该成矿带上最大的石英脉型金矿床。单个矿体延深之大,厚度、品位变化之稳定,且易采易选,这在胶东东部地区乃至全国尤为罕见。  相似文献   
906.
Abstract

A water balance model of Lake Victoria that can be used to assess rainfall from lake level, is derived. The model utilizes satellite estimates of rainfall directly over the lake. The model, initially derived and calibrated for the period 1956–1978, is reformulated here in such a way that all water balance terms except evaporation can be calculated from a combination of catchment rainfall and level of the lake. The reformulated model is validated and used to predict lake level fluctuations during the period 1931–1994. An error analysis is also performed. The model is then “inverted” to solve for mean rainfall conditions during various intervals of changing lake levels. For modern periods with known rainfall conditions, the error in model estimates is of the order of 1%.  相似文献   
907.
908.
A linearized instability analysis model with five unknowns was proposed to describe disturbance motions under general oceanic background conditions, including large-scale current shear, density stratification, frontal zone, and arbitrary topography. A unified linear theory of wavelike perturbations for surface gravity waves, internal gravity waves and inertial gravity waves was derived for the adiabatic case, and the solution was then found using Fourier integrals. In this theory, we discarded the assumptions widely accepted in the literature concerning derivations of wave motions such as the irrotationality assumption for surface gravity waves, the rigid-lid approximation for internal gravity waves, and the long-wave approximation for inertial gravity waves. Analytical solutions based on this theory indicate that the complex dispersion relationships between frequency and wave-number describing the propagation and development of the three types of wavelike perturbation motions include three components: complex dispersion relationships at the sea surface; vertical invariance of the complex frequency; and expressions of the vertical wave-number (phase). Classical results of both surface waves and internal waves were reproduced from the unified theory under idealized conditions. The unified wave theory can be applied in the dynamical explanation of the generation and propagation properties of internal waves that are visible in the satellite SAR images in the southern part of the China Seas. It can also serve as the theoretical basis for both a numerical internal-wave model and analytical estimation of the ocean fluxes transported by wavelike perturbations.  相似文献   
909.
Much attention has recently been focused on the effects that climate variability and human activities have had on runoff. In this study, these effects are quantified using three methods, namely, multi‐regression, hydrologic sensitivity analysis, and hydrologic model simulation. A conceptual framework is defined to separate the effects. As an example, the change in annual runoff from the semiarid Laohahe basin (18 112 km2) in northern China was investigated. Non‐parametric Mann‐Kendall test, Pettitt test, and precipitation‐runoff double cumulative curve method were adopted to identify the trends and change‐points in the annual runoff from 1964 to 2008 by first dividing the long‐term runoff series into a natural period (1964–1979) and a human‐induced period (1980–2008). Then the three quantifying methods were calibrated and calculated, and they provided consistent estimates of the percentage change in mean annual runoff for the human‐induced period. In 1980–2008, human activities were the main factors that reduced runoff with contributions of 89–93%, while the reduction percentages due to changes in precipitation and potential evapotranspiration only ranged from 7 to 11%. For the various effects at different durations, human activities were the main reasons runoff decreased during the two drier periods of 1980–1989 and 2000–2008. Increased runoff during the wetter period of 1990–1999 is mainly attributed to climate variability. This study quantitatively separates the effects of climate variability and human activities on runoff, which can serve as a reference for regional water resources assessment and management. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
910.
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