基准镇流器的校准方法及不确定度评定

为可靠测试基准镇流器的电压/电流比、功率因数,本文简要介绍了基准整流器的校准方法,对校准结果的不确定度评定进行了分析,给出了测量结果的不确定度,同时验证了该校准方法的可行性。     

Re-politicising water governance: exploring water re-allocations in terms of justice

Contemporary socio-economic transformations in South Asia are creating increasingly serious water problems (scarcity, flooding, pollution) and conflicts. Conflicts over water distribution, water-derived benefits, and risks often play out along axes of social differentiation like caste, wealth, and gender. Those with least power, rights, and voice suffer lack of access, exclusion, dispossession, and further marginalisation, resulting in livelihood insecurity or increased vulnerability to risks. In this paper we propose analysing these problems as problems of justice – problems of distribution, recognition, and political participation. Drawing on wider environmental justice approaches, a specific water justice focus needs to include both the specific characteristics of water as a resource and the access, rights, and equity dimensions of its control. We argue that recognising water problems as problems of justice requires a re-politicisation of water, as mainstream approaches to water resources, water governance, and legislation tend to normalise or naturalise their – basically political – distributional assumptions and implications. An interdisciplinary approach that sees water as simultaneously natural (material) and social is important here. We illustrate these conceptual and theoretical suggestions with evidence from India.     

黄土丘陵区退耕还林对土壤真菌群落的影响

退耕还林显著影响了黄土高原土壤细菌群落结构与组成特征.然而,作为土壤微生物群落的重要组成部分,黄土高原土壤真菌落结构与组成特征如何响应退耕还林并不十分清楚.以山西省右玉县贾家窑黄土高原缓坡丘陵为研究区域,以耕地(玉米地和糜子地)和人工林地(沙棘林和柠条林)土壤为研究对象,通过18S rRNA高通量测序技术,研究了退耕还林对土壤真菌群落结构与组成特征的影响.结果发现,黄土高原丘陵区耕地和林地土壤中子囊菌门(Ascomycota)占绝对优势(61.03%～78.06%),毛霉门(Mucoromycota)次之(12.11%～17.13%),担子菌门(Basidiomycota)再次之(6.15%～18.42%),壶菌门(Chytridiomycota)等其余真菌门的相对丰度较低.退耕还林显著降低了子囊菌门的相对丰度而增加了担子菌门的相对丰度.属分类水平下,退耕还林显著影响了毛壳菌属(Chaetomium)、被孢霉属(Mortierella)、镰刀菌属(Fusarium)和地舌菌属(Geoglossum)等的丰度.镰刀菌属(Fusarium)等植物病原性真菌在耕地土壤中被富集.非度量多维尺度...     

Assessing sustainability in nature-inspired design

In the field of sustainable product development, a new perspective for approaching sustainability has been advocated, challenging designers and engineers to aim beyond ‘reducing unsustainability’. Several design strategies – including Biomimicry and Cradle to Cradle – have been suggested for developing truly sustainable, or ‘beneficial’, products. But do these strategies help in developing such products, and how to assess their ‘sustainability’? Based on a review of the objectives in nature-inspired design, we argue that assessing environmental sustainability is not straightforward. Whereas both Biomimicry and Cradle to Cradle build on the perspective of ‘achieving sustainability’, current life-cycle assessment-based tools are geared towards reducing current impacts. As a consequence, existing tools are insufficiently equipped for the purpose of the assessment: they do not cover some of the main results that nature-inspired design is set out to accomplish. To be able to include these results, we propose two new constituents to current life-cycle-based product assessment: assessing against conditions of sustainability and assessing ‘achievement’, the extent to which these conditions of sustainability have been achieved. Furthermore, the product context needs to be included for assessing beneficial impacts. This article discusses how these constituents can contribute to an assessment tool that enables designers and engineers to assess the development of environmentally sustainable solutions.     

Multi-scales Analysis of Driving Forces on Land Use/Cover Change in China: Taking Farmland Returning to Forest or Grassland as a Case

Abstract

Increasing populations are causing an increase in food demands, and the area of cultivated land expands every year. Inappropriate land transition from ecology to production results in the constant decline of the ecological security level and influences the regional sustainable development. Adjusting unreasonable land use mode and reconstructing natural land cover are important ways to maintain and improve the ecological environment. Also reclaiming farmland as areas for forests and grasslands (FRFG) is another way. Successful implementation of FRFG in China is the result of comprehensive effect of the multi-scales driving forces. This paper analyses the driving forces of FRFG in China on a national (country)—regional (province)—local (county)—household (farmer) level scale, and the results are: driving forces at the national scale include ecological and food security and the western development of China; at the regional scale, ecological and economic benefits become the main factors to influence the dimension of FRFG under the same policy. The driving forces can be divided into 6 types: industrial structure adjustment, water source protection, flood prevention, the Three-Gorge Project protection, reduction of the amount of sediment flowing into the Yellow River and wind erosion desertification prevention. The driving forces at the local scale can be divided into 12 types with developing leading industries, increasing farmers' income and improving agricultural production conditions as the main types; at the household scale, the national policy meeting farmers' demands and the optimization of individual interests are all driving forces.     

Acid deposition and watershed characteristics in relation to lake chemistry in northeastern Minnesota

The relationship between lake sensitivity to atmospheric acidic inputs and the neutralization capacity of watersheds is examined for 267 lakes in northeastern Minnesota. Three water chemistry/sensitivity measures (color, sulfate, and alkalinity) are correlated with variables representative of precipitation and sulfate inputs, hydrology, and the acid neutralization capacity of various watershed components. An ordinal scale for ranking bedrock and surficial deposit neutralization capacity is presented. The watershed variables found to account for the largest percentages of the variability in measured color, sulfate, and alkalinity levels are determined. Color is strongly related to the presence of peat or marsh and hydrologic renewal time, whereas sulfate is primarily related to atmospheric deposition, evaporative concentration, bedrock type, and the presence of coniferous forest. Variation in alkalinity is the most difficult of the water chemistry measures to explain; for headwater lakes, atmospheric sulfate input, water renewal time, the presence of deciduous forest, and the weatherability of underlying bedrock determine much of its variability. The results illustrate important averaging properties of watersheds from small headwater systems to large drainages and the difficulty in obtaining correlations for some water quality measures (e.g., alkalinity) when some variables, such as soils and land cover, are available only as large-area averages.     

天津港北煤南移环境效益探讨

分析了天津港煤、焦炭储运的现状及其污染情况,南疆物流散货中心作为实现“北煤南移”的重大战略,将彻底改变堆场、储运场凌乱分布的局面,改变现有煤尘污染的情况,具有良好的环境、社会效益。     

Evaluation of theories and calculation tools in ecology

The concept of validation is inappropriate for the evaluation of ecological models. Classification of models into logical, theoretical, and calculation tool (predictive) types provides a sounder basis for choosing an evaluation technique. The dangers of model “tuning” are presented.     

Privacy-seeking behavior in an elementary classroom

This study observed privacy-seeking behavior in an elementary classroom, investigated individual differences in privacy seeking, and compared preferences for private spaces varying in degree of enclosure. Four privacy booths were placed in a fourth-grade classroom. A ticket system was used to assess booth use. Information on personality and background variables was obtained with self-report, peer, teacher, and parent questionnaires. After an initial period of enthusiasm, overall booth use declined sharply. However, analysis revealed substantial individual variation in booth use that remained consistent throughout the study. For boys, booth use was significantly correlated with teachers' ratings of sociability, aggressiveness, and distractibility. For girls, a significant positive relationship was found between privacy seeking at home and in school. Self-reported desire for privacy was uncorrelated with actual privacy-seeking behavior in the classroom. No significant differences in the use of the various booths were found, although self-reported preferences clearly favored the booth that allowed visual access to the rest of the classroom when desired.