首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   82篇
  免费   7篇
  2024年   2篇
  2023年   2篇
  2021年   1篇
  2020年   2篇
  2019年   1篇
  2018年   1篇
  2016年   3篇
  2015年   12篇
  2014年   3篇
  2013年   39篇
  2012年   3篇
  2011年   5篇
  2010年   1篇
  2009年   2篇
  2008年   1篇
  2006年   4篇
  2005年   1篇
  2003年   2篇
  2002年   2篇
  2001年   1篇
  2000年   1篇
排序方式: 共有89条查询结果,搜索用时 15 毫秒
1.
四川省馆藏文物保存环境监测区域中心(简称四川区域中心)平台,经过两年多的运行实践,实现了12家博物馆监测站的集成联网。本研究分析了区域中心监测平台运行中常见故障现象的表现形式、故障原因及故障率。结果表明:监测平台的主要故障现象为传输异常和数据异常;除温湿度外的其他监测终端故障率较高;软件平台建设也不够完善,导致数据利用率低,尚不能实现风险评估、预测预警和预防调控等管理功能。针对分析发现的问题,提出一些相应的技术措施和管理措施,为有效降低故障的发生率,提升国内区域中心平台建设提供一定的指导和参考。  相似文献   
2.
Monitoring is deemed crucial for the incentivization of a decentralized organization, but its function relies on information transparency between the central authority and the delegated individuals. We test this hypothesis by considering changes in the fiscal behavior of Chinese county governments following an exogenous fiscal reform in 2004/2005 that removed information obstacles between provinces and counties. Employing data on 590 Chinese counties from 2000 to 2009, we find that counties in the reform provinces adopt a more proactive fiscal policy after the reform, suggesting that they become more incentivized in the political competition for economic growth. Such effects are stronger in counties with fewer competing peers and counties with either high or low ranks in the records of economic growth among peers. The increase in counties' productive spending leads to higher economic growth in later years.  相似文献   
3.
ABSTRACT

Along Florida’s nearly 13,000 km of shoreline, nearly 4000 archaeological sites and over 600 recorded historic cemeteries are at risk from climate change impacts including coastal erosion and a 2-metre rise in sea level. In 2016, the Florida Public Archaeology Network (FPAN) created the Heritage Monitoring Scouts (HMS Florida) programme to engage the public in monitoring sites at risk. The programme grew quickly during the first year of operation to include 233 volunteers who submitted 312 monitoring forms. The programme exists beyond the singular act of a volunteer reporting site conditions; across Florida, varied combinations of local partnerships present unique opportunities for programmes, for example, the pilot program at the Guana Tolomato Matanzas National Estuarine Research Reserve. Preliminary outcomes from the first year of HMS Florida and the pilot indicate the programme is effective in public engagement and a powerful management tool for tracking change to sites over time.  相似文献   
4.
Historical towers, in particular medieval towers, are an important part of cultural heritage, and their preservation mandates monitoring and detailed analyses of vulnerability under seismic actions as well as of their long-term performance. Certain aspects of structural nature are linked to the masonry behavior as a unilateral material, and other are aspects related to the interaction with soft soil conditions. This study aims to contribute to the aspects of preservation by exploring the role of the soil-structure interaction in predicting the behavior of the structures, with specific reference to the well-documented case history of the medieval Ghirlandina Tower (Modena, Italy). A significant contribution comes from an experimental identification analysis, performed in the presence of ambient vibration. A novel finding is that the soil structure interaction cannot be neglected, in contrast to most published identification analyses that usually assume the structure to have rigid constraint at base.  相似文献   
5.
CO2 injected into rock formations for deep geological storage must not leak to surface, since this would be economically and environmentally unfavourable, and could present a human health hazard. In Italy natural CO2 degassing to the surface via seeps is widespread, providing an insight into the various styles of subsurface ‘plumbing’ as well as surface expression of CO2 fluids. Here we investigate surface controls on the distribution of CO2 seep characteristics (type, flux and temperature) using a large geographical and historical data set. When the locations of documented seeps are compared to a synthetic statistically random data set, we find that the nature of the CO2 seeps is most strongly governed by the flow properties of the outcropping rocks, and local topography. Where low‐permeability rocks outcrop, numerous dry seeps occur and have a range of fluxes. Aqueous fluid flow will be limited in these low‐permeability rocks, and so relative permeability effects may enable preferential CO2 flow. CO2 vents typically occur along faults in rocks that are located above the water table or are low permeability. Diffuse seeps develop where CO2 (laterally supplied by these faults) emerges from the vadose zone and where CO2 degassing from groundwater follows a different flow path due to flow differences for water and CO2 gas. Bubbling water seeps (characterized by water bubbling with CO2) arise where CO2 supply enters the phreatic zone or an aquifer. CO2‐rich springs often emerge where valleys erode into CO2 aquifers, and these are typically high flux seeps. Seep type is known to influence human health risk at CO2 seeps in Italy, as well as the topography surrounding the seep which affects the rate of gas dispersion by wind. Identifying the physical controls on potential seep locations and seep type above engineered CO2 storage operations is therefore crucial to targeted site monitoring strategy and risk assessment. The surface geology and topography above a CO2 store must therefore be characterized in order to design the most effective monitoring strategy.  相似文献   
6.
Tie-rods are essential structural elements, which have been employed for centuries in masonry historical buildings, either during the construction or in successive strengthening interventions, with the aim of containing dangerous horizontal actions. The actual work conditions of these tie-rods, which are strongly influenced by their load history, are difficult to be quantified theoretically, and an effective method for their measure is of great importance in order to ensure the efficiency of these elements during the time and the stability of the entire building. Common measurements are often carried out adopting models based upon significant simplifications, like, for example, hinges at the extremities. These assumptions, rarely represent the real work conditions for anchorages. In this work, a non-destructive testing method is presented, based upon sophisticated dynamical models that can take into consideration many of the circumstances neglected by the simplified models. Four case studies are extensively described, trying to embrace the most common situations in term of peculiar features of the building, structural configuration, and load history. The discussion of the results yields the safety margin of the rod with respect to the material failure and provides important indications about the overall stability of the whole building.  相似文献   
7.
Oxygen is a key parameter in the degradation of archaeological material, but little is known of its dynamics in situ. In this study, 10 optical oxygen sensors placed in a 2 m deep test pit in the cultural deposits at Bryggen in Bergen have monitored oxygen concentrations every half hour for more than a year. It is shown that there is a significant spatial and temporal variation in the oxygen concentration, which is correlated to measured soil characteristics, precipitation, soil water content and degradation of organic material. In these deposits oxygen typically occurs when the air content of the soil exceeds 10–15% vol, while oxygen dissolved in infiltrating rainwater is of less importance for the supply of oxygen in the unsaturated zone.  相似文献   
8.
ABSTRACT

The interest in automatic modal parameter extraction techniques has increased significantly in recent years because of the rising demand for Continuous Structural Health Monitoring (CSHM) of civil structures and infrastructures. The wider use of CSHM is related to its capability for early damage detection and therefore to its usefulness for planning maintenance and strengthening interventions. This article presents the main steps followed in creating a robust routine to run on an online basis the first-ever Continuous Vibration-Based Structural Health Monitoring (CVB-SHM) of a large masonry oval dome, i.e., the dome of the Regina Montis Regalis Basilica, also known as Sanctuary of Vicoforte. The procedure uses an output-only stochastic subspace identification method complemented by an automatic analysis applied to identification results, which are typically provided in terms of stabilization diagrams. In this study, the fully automatic procedure also includes a hierarchical clustering algorithm to separate authentic from spurious modes.  相似文献   
9.
上海博物馆书画陈列馆环境监测与治理   总被引:3,自引:3,他引:0  
为了全面了解上海博物馆书画陈列馆陈列空气环境现状,对它进行了氮氧化物、二氧化硫、臭氧的检测,得出了氮氧化物是主要污染源。为此用氮氧化物自动测定仪、铜银试片法、On guard2000对此进行了较长时间的监测,在监测数据分析的基础上确定了治理方案,并已在实施。  相似文献   
10.
过去几十年,美国普滤公司合作开发了一种可以用来精确评价被保护环境中存在破坏可能性的技术,用来保护珍贵的文物,艺术品及历史档案资料。他们一方面研究开发了能精确评估被保护环境的反应监测仪器和监测技术,另一方面又制订一套新的环境分级标准,使文物保护者了解被保护环境是否是安全的。现把这种文物、档案、图书保存环境的反应监测技术和环境评估的新标准介绍给国内的同行们。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号