一种改进的灾害新闻3要素提取方法研究*

为提取灾害性新闻中的基本要素,迅速掌握灾害事件信息和发展趋势,将目标分类和命名实体识别（named entity recognition,NER）相结合,提出改进的灾害新闻3要素提取方法。构建滑动窗检测器搭载不同的分类模型,实现对新闻文本的灾害主题识别与时空位置要素范围判定,结合命名实体识别完成对时空位置要素的精准提取,并以灾害事故信息文本为例进行测试。研究结果表明:通过在火灾、地震和滑坡新闻中进行数据集中测试,发现本文方法相较于LSTM,BILSTM,BILSTM-CRF提取效果更优;本文方法可对大量灾害性新闻的灾害3要素进行识别提取,对灾害信息进行时空规律分析,研究结果可在灾害应急响应中发挥重要作用。     

中国西北地区1961—2009年极端高温事件的演变特征

利用中国西北地区135个测站1961—2009年历年逐日地面最高气温和NCEP/NCAR资料,采用线性趋势分析、Mann-Kendall、子波分析、合成分析等方法,分析了近49 a西北地区高温事件的演变特征。结果表明:西北地区极端高温的高值区在新疆大部分地区、河西走廊西部、甘肃中北部、陇东南、宁夏北部和陕西,这些地方的高温阈值在30 ℃以上;区域年极端高温频率以1.8 d/10 a的速率显著增多,1970年代中期高温日数发生由少至多的转型,1994年有突变,高温频数有显著的3~5 a周期,目前仍处于高温频发阶段;极端最高气温介于22.5~47.8 ℃之间,最大值出现在吐鲁番盆地。4—10月皆可出现高温,但主要出现在6—8月,其中7月最多。6月高温频率增加最显著,其他月份增加不明显;高温越强,持续日数越长,高温频发的时段也是高温最强的时段。气候变暖导致极端高温事件增多,强度增强。从大气环流合成分析表明,乌山脊、巴尔喀什湖低槽和蒙古脊中高层位置稳定,大气为准正压状态,西北地区在蒙古高脊控制下,有利于形成大范围持续性高温天气。     

煤矿安全管理体系缺失和不安全行为研究

现阶段我国煤矿的安全技术、生产设备都有大幅提高,但事故发生率仍居高不下,其主要原因是安全管理体系的缺失和存在不安全行为。为预防事故的发生,研究煤矿安全管理体系和不安全行为是十分必要的。为此,构建适合分析煤矿安全管理体系缺失和不安全行为的HFACS框架。按照HFACS框架,采用SPSS13.0对515起煤矿伤亡事故发生的原因进行整理分类,运用χ2检验和让步比(OR)分析安全管理体系缺失情况,不安全行为发生的原因,以及两者之间的内在联系。研究结果表明,安全管理体系缺失主要表现在管理文化的缺失和监督不充分,不安全行为主要表现在决策差错和习惯性违规。安全管理体系缺失是导致不安全行为的潜在根本原因。     

Applying Satellite Imagery to Triage Assessment of Ecosystem Health

Considerable evidence documents that certain changes in vegetation and soils result in irreversibly degraded rangeland ecosystems. We used Advanced Very High Resolution Radiometer (AVHRR) imagery to develop calibration patterns of change in the Normalized Difference Vegetation Index (NDVI) over the growing season for selected sites for which we had ground data and historical data characterizing these sites as irreversibly degraded. We used the NDVI curves for these training sites to classify and map the irreversibly degraded rangelands in southern New Mexico. We composited images into four year blocks: 1988–1991, 1989–1992, and 1990–1993. The overlap in pixels classified as irreversibly degraded ranged from 42.6% to 84.3% in year block comparisons. Quantitative data on vegetation composition and cover were collected at 13 sites within a small portion of the study area. Wide coverage reconnaissance of boundaries between vegetation types was also conducted for comparisons with year block maps. The year block 1988–1991 provided the most accurate delineation of degraded areas. The rangelands of southern New Mexico experienced above average precipitation from 1990–1993. The above average precipitation resulted in spatially variable productivity of ephemeral weedy plants on the training sites and degraded rangelands which resulted in much smaller areas classified as irreversibly degraded. We selected imagery for a single year, 1989, which was characterized by the absence of spring annual plant production in order to eliminate the confounding effect of reflectance from annual weeds. That image analysis classified more than 20% of the rangelands as irreversibly degraded because areas with shrub-grass mosaic were included in the degraded classification. The single year image included more than double the area classified as irreversibly degraded by the year blocks. AVHRR imagery can be used to make triage assessments of irreversibly degraded rangeland but such assessment requires understanding productivity patterns and variability across the landscapes of the region and careful selection of the years from which imagery is chosen.     

Mapping wetlands in the Lower Mekong Basin for wetland resource and conservation management using Landsat ETM images and field survey data

The Mekong River Basin is considered to be the second most species rich river basin in the world. The 795,000 km(2) catchment encompasses several ecoregions, incorporating biodiverse and productive wetland systems. Eighty percent of the rapidly expanding population of the Lower Mekong Basin (LMB), made up in part by Lao PDR, Thailand, Cambodia and Viet Nam, live in rural areas and are heavily reliant on wetland resources. As the populations of Cambodia and Lao PDR will double in the next 20 years, pressure on natural resources and particularly wetlands can only increase. For development planning, resource and conservation management to incorporate wetland issues, information on the distribution and character of Mekong wetlands is essential. The existing but outdated wetland maps were compiled from secondary landuse-landcover data, have limited coverage, poor thematic accuracy and no meta-data. Therefore the Mekong River Commission (MRC) undertook to produce new wetland coverage for the LMB. As resources, funding and regional capacity are limited, it was determined that the method applied should use existing facilities, be easily adaptable, and replicable locally. For the product to be useful it must be accepted by local governments and decision makers. The results must be of acceptable accuracy (>75%) and the methodology should be relatively understandable to non-experts. In the first stage of this exercise, field survey was conducted at five pilot sites covering a range of typical wetland habitats (MRC wetland classification) to supply data for a supervised classification of Landsat ETM images from the existing MRC archive. Images were analysed using ERDAS IMAGINE and applying Maximum Likelihood Classification. Field data were reserved to apply formal accuracy assessment to the final wetland habitat maps, with resulting accuracy ranging from 77 to 94%. The maps produced are now in use at a Provincial and National level in three countries for resource and conservation planning and management applications, including designation of a Ramsar wetland site of international importance.     

利用膜技术实现烟气脱硫吸收剂循环的研究

利用膜技术实现钠碱法脱硫吸收液的再生循环,流程简单,操作方便。通过介绍钠碱法脱硫吸收液再生原理,探讨了NaHSO3-Na2SO3溶液吸收与再生循环操作流程,分析了膜技术推广应用中存在的主要问题。     

13种花卉植物受硫氧化物混合气体污染的伤害症状及其抗性表现

通过熏气的方法,比较了在硫氧化物混合污染气体的作用下,木本花卉（月季Rosa chinensis,杜鹃Rhododendron simsii,一品红Euphorbia pulcherrima,茉莉花Jasminum sambac）,一、二年生花卉（一串红Salvia splendens,凤仙花Impatiens balsamina）,宿根花卉（君子兰Clivia miniata）,室内观叶植物（文竹Asparagus setacens,吊兰Chlorophytum comosum,沿阶草Ophiopogon bodinieri,朱蕉Cordyline fruticosa,吊竹梅Zebrina pendula,白斑万年青Dieffenbachia bowmannii）中13种花卉植物的叶片伤害症状及植物抗性表现,并对植物受害后的恢复情况进行了追踪观察。发现在同种污染气体的作用下,不同种类的植物表现出不同的伤害症状。植株不同叶龄的叶片对污染气体的敏感性存在一定的差异,幼龄叶不一定比中老龄叶敏感性强。当污染浓度不超过一定阈值时,花卉植物都有不同程度的恢复能力。利用“花卉植物叶片伤害评价系统”对试验植物叶片伤害症状进行了评价,依据评价结果,对试验植物进行了抗性分级。为保证对植物抗性等级划分的准确性,建议制定统一的熏气浓度标准和评价标准。     

企业职业危害综合评价和风险分级系统及其应用

我国企业职业危害形势依然十分严峻,2007年共诊断各类职业病14296例,较2006年增加了24．11％。由于国家在一段时期内不太可能大幅度增加监管人员数量,因此,实施企业职业危害分级监管成为职业危害监管工作的一个紧迫需求。本文从提高企业监管信息化水平角度出发,开发企业职业危害综合评价和风险分级系统。系统即可为政府实施职业危害分级监管提供强有力的技术支撑,也可应用在企业的作业场所职业危害管理工作中,从而提高政府和企业职业危害管理工作技术水平和效率。     

Evaluation of groundwater flow patterns around a dual-screened groundwater circulation well

Dual-screened groundwater circulation wells (GCWs) can be used to remove contaminant mass and to mix reagents in situ. GCWs are so named because they force water in a circular pattern between injection and extraction screens. The radial extent, flux and direction of the effective flow of this circulation cell are difficult to measure or predict. The objective of this study is to develop a robust protocol for assessing GCW performance. To accomplish this, groundwater flow patterns surrounding a GCW are assessed using a suite of tools and data, including: hydraulic head, in situ flow velocity, measured hydraulic conductivity data from core samples, chemical tracer tests, contaminant distribution data, and numerical flow and transport models. The hydraulic head data show patterns that are consistent with pumping on a dual-screened well, however, many of the observed changes are smaller than expected. In situ thermal perturbation flow sensors successfully measured horizontal flow, but vertical flow could not be determined with sufficient accuracy to be useful in mapping flow patterns. Two types of chemical tracer tests were utilized at the site and showed that much of the flow occurs within a few meters of the GCW. Flow patterns were also assessed based on changes in contaminant (trichloroethylene, TCE) concentrations over time. The TCE data clearly showed treated water moving away from the GCW at shallow and intermediate depths, but the circulation of that water back to the well, except very close to the well, was less clear. Detailed vertical and horizontal hydraulic conductivities were measured on 0.3 m-long sections from a continuous core from the GCW installation borehole. The measured vertical and horizontal hydraulic conductivity data were used to construct numerical flow and transport models, the results of which were compared to the head, velocity and concentration data. Taken together, the field data and modeling present a fairly consistent picture of flow and transport around the GCW. However, the time and expense associated with conducting all of those tests would be prohibitive for most sites. As a consequence, a sequential protocol for GCW characterization is presented here in which the number of tools used can be adjusted to meet the needs of individual sites. While not perfect, we believe that this approach represents the most efficient means for evaluating GCW performance.     

Circulation and Stream Plume Modeling in Conesus Lake

A three-dimensional hydrodynamic model that includes the effect of drag from macrophytes was applied to Conesus Lake to study the seasonal circulation and thermal structure during spring and early summer. Local weather conditions and stream flow data were used to drive the model. The drag coefficient for macrophytes was calculated as a function of leaf density. In general, the model results show good agreements with the observations, including vertical temperature profiles measured at two locations and average surface temperature derived from calibrated thermal imagery for large-scale simulations of the entire lake. Additional high-resolution simulations were carried out to understand water circulation and transport of sediment and model-generated tracer during hydrometeorological events at stream mouths for two experimental sites. The model results show that the plume development at stream mouths during storm events in Conesus Lake are site-dependent and may either be current- or wind-driven. The results also show a significant effect from the presence of macrophytes on sediment deposition near stream mouths.