基于循环修正模式的云南省水资源短缺程度分析

区域水资源短缺评价是水资源风险研究的基础。前期的研究多采用单一评价方法进行,致使评价结果存在差异。论文提出采用循环修正模式对单一评价方法得出的不同评价结果进行组合修正。通过构建云南省水资源短缺综合评价指标体系,利用模糊物元、模糊识别等多种单一评价方法进行评价,最后运用平均值法、Boarda法和Compeland法三种组合评价方法对单一评价方法得到的不同结果进行组合评价,建立了基于循环修正模式的水资源短缺程度评价模型并加以应用,给出了云南省16个地、市、州的水资源短缺程度的排序及其缺水类型的划分。     

A hybrid model based on smooth transition periodic autoregressive and Elman artificial neural network for wind speed forecasting of the Hebei region in China

Wind energy, one of the most promising renewable and clean energy sources, is becoming increasingly significant for sustainable energy development and environmental protection. Given the relationship between wind power and wind speed, precise prediction of wind speed for wind energy estimation and wind power generation is important. For proper and efficient evaluation of wind speed, a smooth transition periodic autoregressive (STPAR) model is developed to predict the six-hourly wind speeds. In addition, the Elman artificial neural network (EANN)-based error correction technique has also been integrated into the new STPAR model to improve model performance. To verify the developed approach, the six-hourly wind speed series during the period of 2000–2009 in the Hebei region of China is used for model construction and model testing. The proposed EANN-STPAR hybrid model has demonstrated its powerful forecasting capacity for wind speed series with complicated characteristics of linearity, seasonality and nonlinearity, which indicates that the proposed hybrid model is notably efficient and practical for wind speed forecasting, especially for the Hebei wind farms of China.     

利用CFSR数据开展海上风电场长年代风能资源评估

开展长年代风能资源评估可为海上风电场的可行性研究和风险评估提供依据和支撑。创新性地引入了气候预测系统再分析(CFSR)数据,以江苏响水海上风电场为例开展了长年代风能资源评估,结果表明:CFSR数据10 m高度风速与海上气象塔10 m高度风速的平均偏差为-0.2 m·s~(-1),均方根误差为1.9 m·s~(-1);CFSR数据10 m高度风速与海上气象塔90 m高度风速的相关系数范围在0.359~0.619,相比气象站的相关系数提高了40%~90%;长年代订正得到海上气象塔90 m高度近30 a的风数据,多年平均风速为6.9 m·s~(-1),标准差为0.2 m·s~(-1)(2.9%);测算出海上风电场近30年的等效满负荷小时数,多年平均值为2 423 h,标准差为112 h(4.6%);评估出25 a一遇(海上风电场的寿命期)、10 a一遇、5 a一遇的最小年平均风速分别为6.6、6.7和6.8 m·s~(-1),最小年等效满负荷小时数分别为2 227、2 280和2 329 h。利用CFSR数据开展海上风电场长年代风能资源评估在技术上是可行的。     

基于卫星影像的太湖蓝藻水华遥感强度指数和等级划分算法设计

对太湖地区近10余年来共32景Landsat TM/ETM遥感影像进行大气校正处理,获得地表反射率影像,在这些影像上采集了分布在不同片区、不同发生季节、不同集聚程度的蓝藻水华样区,提取了不同蓝藻水华的可见一近红外波段反射率数据.统计表明蓝藻水华在TM 4波段的反射率有较宽的动态范围,能定量反映蓝藻集聚程度,TM 2也是...     

小群体行为作用下的地铁站疏散模型研究

为研究小群体行为作用对地铁站突发事件人群疏散效率的影响，基于社会力模型理论和智能体技术，构建地铁站人群疏散模型。分析小群体趋向性、协调一致性等行为特征，运用社会力模型理论，计算小群体成员移动速度；量化小群体行为对群体内部成员作用大小，修正成员期望速度，确定人群疏散速度；以某地铁站火灾事故为例，分别模拟单人疏散场景和混合疏散场景。研究结果表明:混合疏散场景仿真时间比单人疏散场景仿真时间延长12.29%，平均绕行距离比单人疏散增加38.8%，小群体行为降低了地铁站突发事件人群疏散效率。     

Risk-based Decision Process for Arsenic in Soils: Implications of Conservative Protocols

Making defensible risk-based decisions is a complex process that incorporates risk assessment into a risk management framework. Many site investigations require additional study, negotiations and/or actions for arsenic detected in soil samples, in many cases where no process related sources are identified and no other chemicals of concern are identified. Regulatory agencies develop guidance to standardize approaches to risk-based site investigations that focus on achieving "safe" concentrations. For arsenic, the action level is frequently in the "gray region", a U.S. Environmental Protection Agency (USEPA) term associated with a region of high uncertainty for risk management decisions in the "decision performance curve" associated with the data quality objective (DQO) process. Recognizing the conservative nature of the risk-based screening value for arsenic, approaches to enforce this level (or proof of comparability to natural background) may have numerous consequences including ineffective use of resources, stigmas on properties or actions at industrial or hazardous sites that are inconsistent with their regional setting. Florida has developed regulations and guidance on investigation of brownfield sites and has supported a study by the University of Florida (UF) to evaluate natural background concentrations in Florida soils. This paper discusses the sources of uncertainty near the soil cleanup target levels (SCTLs) in the Florida decision-making framework.     

长江三角洲地区CO2浓度本底特征及来源分析

二氧化碳(CO₂)是引起全球变暖的最主要的温室气体(GHGs),直接观测大气CO₂浓度对于研究人类活动和自然活动对大气温室气体的贡献至关重要,而在多个高度上观测大气CO₂浓度则有助于明晰CO₂浓度的时空变化规律,确定其影响机制.本文利用临安区域大气本底站2018-12—2020-11不同高度(距地面21 m、53 m)处的CO₂在线观测数据,结合日变化及地面风的影响,对观测数据进行筛分,采用HYSPLIT后向轨迹模型和潜在源贡献因子法,初步探讨气象因素以及大气远距离传输对长江三角洲地区大气CO₂浓度的影响.结果表明,临安站高低层大气CO₂日变化呈夜间高于白天的特点;低层CO₂浓度大于高层,冬季高低层浓度差小于其他三季;日较差呈夏季>春季>秋季>冬季的特点;大气CO₂本底季节变化由于受到风向和气团传输的影响呈现出冬季>春季>秋季>夏季的特点;潜在源贡献分析得...     

Positive vs. false detection: A comparison of analytical methods and performance for analysis of cyclic volatile methylsiloxanes (cVMS) in environmental samples from remote regions

Contamination and analytical variation can significantly hinder trace analysis of cyclic methyl volatile siloxanes (cVMS); potentially resulting in the report of false positives at concentrations approaching detection limits. To assess detection and variation associated with trace cVMS analysis in environmental matrices, a co-operative laboratory comparison for the analysis of octametylcyclotetrasiloxane (D4), decamethylcylcopentasiloxane (D5), and dodecametylcyclohexasiloxane (D6) in sediment and biota from the Svalbard Archipelago was conducted. Two definitions of detection limits were evaluated in this study; method detection limits (MDL, matrix defined) and limits of detection (LOD, solvent defined). D5 was the only cVMS detected above both LOD (0.08–0.81 ng g⁻¹ ww) and MDL (0.47–2.36 ng g⁻¹ ww) within sediment by all laboratories where concentrations ranged from 0.55 to 3.91 ng g⁻¹ ww. The percentage of positive detects for D5 decreased by 80% when MDL was defined as the detection limit. D5 was also detected at the highest frequency among all laboratories in fish liver with concentrations ranging from 0.72 to 345 ng g⁻¹ ww. Similar to sediment, percentage of positive detects for D5 decreased by 60% across all laboratories for fish livers when using MDL (0.68–3.49 ng g⁻¹ ww). Similar observations were seen with both D4 and D6, indicating that sample matrix significantly contributes to analytical response variation. Despite differences in analytical methods used between laboratories, good agreement was obtained when using MDL to define detection limits. This study shows the importance of incorporating variation introduced by sample matrices into detection limit calculations to insure data accuracy of cVMS at low concentrations.     

分光光度法与容量法测定COD_(Cr)值的对比实验

本文将CODCr测定的重铬酸钾褪色法运用于本监测中心的日常样品测定中,并且与《GB11914—89水质化学需氧量》方法进行了同时测定,结果相同,另外还推算出了消除硫酸铬干扰产生的曲线校值系数,应用此系数的倒数乘褪色方程的斜率得出新方程,将双波长测定改为单波长测定,两种方程计算结果一致。     

Architecture and engineering students' evaluations of house façades: Preference,complexity and impressiveness

In this study, five different sets of single-family house façades from private suburban cooperative housing developments in Ankara, Turkey, were analyzed; with each set comprising one example each of minimum, intermediate and maximum complexity. Although the houses in each set had the same appearance when they were first built, their façades have since been altered by their owners. The main hypothesis of the study was that preference rates would be high for intermediately altered houses by showing the existence of a U-shaped relationship. On the other hand, it was hypothesized that perceived complexity and perceived impressiveness would have a linear relationship, with perceived complexity increasing and perceived impressiveness decreasing as the complexity level changed. In terms of these two basic hypotheses, it was also assumed that there would be a difference in the ratings of particular respondent groups with different backgrounds. Thus, a questionnaire was given to 100 undergraduate students of the Architecture and Engineering Departments of Gazi University, Ankara (41 from architecture and 59 from engineering). These students were asked to rate a total of 15 photographs from five housing sites with the help of five-point semantic differential scales under three headings; namely: Preference: beautiful – ugly, warm – cold, pleasant – unpleasant; Complexity: unimposing – imposing, simple – complex; and Impressiveness: impressive – unimpressive. The results proved the existence of a U-shaped relationship between complexity and preference criteria. That is, façades representing an intermediate level of complexity were favored over less and more complex ones. The façades that seemed the most impressive were the most complex ones, but these, however, were not the most preferred. Amongst these results, it was also noted that the architecture students replied in a more critical way than the engineering students as they criticized what they saw as negative design decisions.