考虑参数和边界条件不确定性的地下水污染随机模拟

为了分析模型参数的随机变化和边界条件的随机变化对地下水溶质运移模型输出结果的不确定性影响,采用蒙特卡洛模拟对一假想算例展开研究,并结合风险评估阐述不确定性分析结果.首先,建立研究区地下水溶质运移数值模拟模型,并综合利用局部灵敏度分析和全局灵敏度分析方法筛选出对模型输出结果影响较大的参数,连同模型的边界条件(第一类边界条件-水头值)一起作为随机变量.然后,利用优化超参数的高斯过程回归(GPR)方法建立模拟模型的替代模型,代替模拟模型完成蒙特卡洛随机模拟.最后,对随机模拟的结果进行统计分析和区间估计,并利用污染物浓度的概率分布函数对1、2、3号观测井进行地下水污染风险评价.结果表明:置信水平>80%时,1,2,3号观测井污染物浓度值的置信区间分别为34.77~35.03,57.74~58.04,100.07~100.69mg/L.此外,1,2,3号观测井为轻度污染的风险分别为6%,100%,100%;为中度污染的风险分别为0%,0%,99.6%;为重度污染的风险分别为0%,0%,0.5%,藉此为地下水污染修复防治和地下水的合理利用提供可靠参考依据.     

Kinetics of antimony biogeochemical processes under pre-definite anaerobic and aerobic conditions in a paddy soil

While the transformation of antimony(Sb) in paddy soil has been previously investigated, the biogeochemical processes of highly chemical active Sb in the soil remain poorly understood. In addition, there is a lack of quantitative understanding of Sb transformation in soil. Therefore, in this study, the kinetics of exogenous Sb in paddy soils were investigated under anaerobic and aerobic incubation conditions. The dissolved Sb(V) and the Sb(V) extracted by diffusive gradient technique decreased u...     

极端温度条件典型引信电参数变化规律和失效机理

目的 研究某电子时间引信在?60~140 ℃下电参数的变化规律和失效机理。方法 利用高低温试验机开展步进应力强化试验,增加和细化引信检测参数,在被试引信工作状态下全程记录电参数的变化,开展失效机理分析。结果 得到了引信基准频率、电能损耗率等电参数的温度特性规律和参数变化范围,发现了?60 ℃低温掉电、130 ℃高温短路等故障模式和机理,并提出改进建议。结论 验证了极端温度应力叠加电应力的强化试验方法,获得了引信电性能参数变化规律,发现了极端温度条件下新的失效模式和失效机理。     

云南虹鳟鱼的产业化发展前景

分析了国内外虹鳟鱼的发展状况，以及云南虹鳟鱼的产业化前景，提出了相应的发展对策。     

Using diatoms to assess the impacts of prehistoric, pre-industrial and modern land-use on Danish lakes

The impact of contemporary agriculture on Danish lakes is acknowledged to be extreme. In particular, high loading of nutrients from agricultural soils contributes to the eutrophic conditions found in many of Denmark’s lakes. Palaeolimnological studies have shown that human disturbance of the Danish landscape since the introduction of agriculture around 6,000 years ago has had a major impact on lake ecosystems. The European Union’s Water Framework Directive requires an evaluation of reference conditions for lakes, the conditions expected with only minimal human impact. Monitoring data and palaeolimnological studies of Danish lakes demonstrate that many of the most detrimental effects of eutrophication have been experienced in recent decades. A new study has suggested that the reference status for Danish lakes may be set to the status in ad 1850–1900, probably providing attainable, realistic restoration targets for many sites. The aims of this study were to explore the impacts of past and contemporary land-use on Danish lakes, and to consider how appropriate the use of 1850 as a date to define reference status is for these sites. Catchment land-cover data for ad 1800, taken from historical maps, and sedimentary diatom assemblages of the same age, from dated sediment cores, were used to assess the impact of pre-industrial land-use on 20 Danish lakes. Analysis of contemporary land-cover data and surface-sediment diatom assemblages for the 20 sites was also made. In-lake total phosphorus (TP) concentrations were estimated using the sedimentary diatom assemblages and an existing calibration dataset for Danish lakes. The percentage of the lake catchment that was agricultural land in ad 1800 explained 8.8% of the total variation in the diatom data. The land-cover variables ‘built-up areas’ and ‘plantations’, together explained 16.9% of the variation in the diatom data for the modern samples. Diatom-inferred TP concentrations were high for both ad 1800 (mean 112 μg TP L⁻¹) and the present (mean 122 μg TP L⁻¹), the latter estimates reflecting efforts in recent decades to reduce nutrient loading to Danish lakes following very high levels of nutrient enrichment post-1950. The data presented highlight the impact that human activities 200 years ago, particularly agriculture, had on Danish lake systems. The long cultural history and major anthropogenic disturbance of the Danish landscape mean that true reference conditions for lakes (or ‘baseline’ conditions, those found prior to human impacts) can be found only by considering century to millennial timescales.     

基于河流参照状态的季风区域季节性农业灰水足迹核算方法与例证

灰水足迹核算对水资源管理具有重要意义.灰水足迹核算的两个重要参数污染物自然本底浓度和污染物入河系数在季风区域均存在明显的季节性差异,而在之前灰水足迹核算的研究中较少考虑季风区域灰水足迹可能存在的季节性差异.本文以河流总磷的参照状态作为其自然本底浓度核算了承德市农业灰水足迹.结果发现：相较于将总磷自然本底浓度值认为零,将总磷参照状态作为其自然本底浓度值的农业灰水足迹核算结果是其核算结果的1.29倍.农业灰水足迹呈现明显的季节性差异,雨季农业灰水足迹是旱季农业灰水足迹的10.65倍.在2003—2015年承德市农业灰水足迹构成中,种植业灰水足迹占较大比重,并且该比重随时间有增大的趋势.然而,承德市区县粮食产量的增长率与化肥的增长率未表现出显著关系,说明粮食产量的增幅与化肥施用的增幅无关.承德市农业灰水足迹相对较大的区县集中于承德北部区域,主要包括围场县、丰宁县和隆化县;农业灰水足迹相对较小的区县为营子区、双滦区、双桥区和宽城县.本文可阐明季风区域农业灰水足迹核算的季节性差异,以期促进灰水足迹核算方法的发展.     

Multi-dimension apportionment of clean air “parade blue”phenomenon in Beijing

The mass concentration and major chemical components of fine particulate matter were measured before, during and after Beijing''s massive parade commemorating 70th anniversary of the Chinese Victory in World War II on September 3, 2015. Regional emission inventory, positive matrix factorization (PMF), observations from space and backward air mass trajectories were jointly applied to identify the major pollution sources and their temporal and spatial variations. The contributions of emissions, their variations and the meteorological conditions related to the “parade blue” phenomenon in Beijing and its surrounding areas were investigated in detail. The main cause of the decreased PM_2.5 mass concentration was attributed to the absolute reduction in emissions of primary air pollutants. The chemical composition of PM_2.5 varied significantly before, during and after the parade. Fugitive dust particles were well controlled, the secondary formation of PM_2.5 was reduced along with the controlled gaseous precursors'' emissions from vehicles and industrial sources during the temporary intensified control period. During the parade period, the SO₂ and NO₂ column concentrations in Beijing and the surrounding areas decreased sharply, indicating that the coordinated reduction in primary emissions from the surrounding areas of Beijing played an important role in lowering the ambient concentration of SO₂ and NO₂ and accordingly lowered PM_2.5 and improved the regional air quality. A comparison of the temperature, humidity, and wind speed and direction during the same periods in 2014 and 2015 showed that the meteorological conditions positively influenced the achievement of “parade blue”.     

Training of expatriate refugee health workers: Principles and practices

Abstract—This paper describes in detail the separate components of an ideal expatriate refugee health worker training course. Emphasis is given to organizational aspects of such courses.     

乌鲁木齐市冬季大气污染特征及区域集中供热的环境效益浅析

乌鲁木齐市区冬季大气污染严重，属煤烟型污染，究其原因主要有三点：市区处在三面环山的谷地之中，冬季不利于污染物扩散的气象条件；采期煤耗的增加，在大气污染物总排放量明显高于其它季节，而改善市区大气环境质量的有效途径之一就是实现区域集中供热。本文针对乌鲁木齐市幸福路区域集中供热站拟扩建的３台２９ＭＷ热水锅炉，说明区域集中供热对减少污染物排放量，改善大气环境质量有明显的作用。     

云南文化植物及其开发

云南省拥有丰富的植物资源和多样的民族文化，使云南各族人民在长期的生产和生活中不但把植物作为生产和生活资料，而且还赋予植物许多人类文化的内涵，使植物成为传承民族文化的载体之一，因此研究云南文化植物及其资源开发与保护具有深远的意义。以云南民间常见的文化植物为例，从文化植物学的角度，阐述了云南文化植物的特征、分区及其资源的开发与保护价值。