解读GB19606-2004《家用和类似用途电器噪声限值》

本文从多角度对GB 19606-2004标准进行了较为深入的分析,同时详细地比较了该标准与现行家电产品标准中的噪声限值的差异,从而指出生产厂商必须对家电产品噪声限值的变化引起足够的重视,提高产品的噪声水平以满足该强制性标准的要求.     

Food Safety and Ethics: The Interplay between Science and Values

The general public in Europe seems tohave lost its confidence in food safety. Theremedy for this, as proposed by the Commissionof the EU, is a scientific rearmament. Thequestion, however, is whether more science willbe able to overturn the public distrust.Present experience seems to suggest thecontrary, because there is widespread distrustin the science-based governmental controlsystems. The answer to this problem is thecreation of an independent scientificFood Authority. However, we argue thatindependent scientific advice alone is unlikelyto re-establish public confidence. It is muchmore important to make the scientific advicetransparent, i.e., to state explicitlythe factual and normative premises on which itis based. Risk assessments are based on arather narrow, but well-defined notion of risk.However, the public is concerned with a broadervalue context that comprises both benefits andrisks. Transparency and understanding of thepublic's perception of food risks is anecessary first step in establishing theurgently required public dialogue about thecomplex value questions involved in foodproduction.     

算术平均值及其分布

平均值和标准偏差是误差理论和数理统计理论中的两个核心问题.平均值的计算方法虽然简单,但是,它的内涵却并不是十分简单.本文以通俗的语言对平均值的本质作了深入浅出的介绍.     

Do Open-Cycle Hatcheries Relying on Tourism Conserve Sea Turtles? Sri Lankan Developments and Economic–Ecological Considerations

By combining economic analysis of markets with ecological parameters, this article considers the role that tourism-based sea turtle hatcheries (of an open-cycle type) can play in conserving populations of sea turtles. Background is provided on the nature and development of such hatcheries in Sri Lanka. The modeling facilitates the assessment of the impacts of turtle hatcheries on the conservation of sea turtles and enables the economic and ecological consequences of tourism, based on such hatcheries, to be better appreciated. The results demonstrate that sea turtle hatcheries serving tourists can make a positive contribution to sea turtle conservation, but that their conservation effectiveness depends on the way they are managed. Possible negative effects are also identified. Economic market models are combined with turtle population survival relationships to predict the conservation impact of turtle hatcheries and their consequence for the total economic value obtained from sea turtle populations.     

Integrity and Rights of Plants: Ethical Notions in Organic Plant Breeding and Propagation

In addition to obviating the use of synthetic agrochemicals and emphasizing farming in accordance with agro-ecological guidelines, organic farming acknowledges the integrity of plants as an essential element of its natural approaches to crop production. For cultivated plants, integrity refers to their inherent nature, wholeness, completeness, species-specific characteristics, and their being in balance with their (organically farmed) environment, while accomplishing their “natural aim.” We argue that this integrity of plants has ethical value, distinguishing integrity of life, plant-typic integrity, genotypic integrity, and phenotypic integrity. We have developed qualitative criteria to ethically evaluate existing practices and have applied these criteria to assess whether current plant breeding and propagation techniques violate the integrity of crop plants. This process has resulted in a design of a holistic, scientific approach of organic plant breeding and seed production. Our evaluation has met considerable criticism from mainstream (crop) scientists. We respond to the following questions: (1). Can ethics be incorporated into objective crop sciences? (2). What is the nature of the intrinsic value of plants in organic farming? We argue that criteria to take integrity into account can only be assessed from a holistic perspective and we show that a holistic approach is needed to design such ethical notions in a consistent way. The ethical notions have been further elaborated by formulating human responsibility and respect towards crop plants. Responsibility and respect can only be shown by providing crop plants the right to be nurtured and to express natural behavior at all levels of integrity.     

The threat of abandonment in socio-ecological landscapes: Farmers’ motivations and perspectives on high nature value grassland conservation

Future sustainability of the conservation management of socio-ecological landscapes is typically reliant on on-going agricultural management. Such management may be threatened by changes in the drivers of management and the fragility of the stakeholder networks that deliver management. This study examined evidence for the risk of abandonment in a series of case study high nature value (HNV) grassland sites. The work found that the motivation of farmers to participate in the conservation management was typically limited and often marginal. Landowners and conservation stakeholders who relied on partner farmers to manage such sites often struggled to recruit and retain their participation, leading to increased turnover among managing farmers and to some sites being under-managed. Primary reasons for difficulty of recruitment and farmer turnover included a lack of candidate farmers in the local landscape, and the marginal and fluctuating economics of grassland management. A trend towards greater financial incentivisation of farmers was evident, which policy-makers responsible for agri-environment schemes should note, and elsewhere some conservation organisations were seen to be bringing grassland management in-house. Farmers’ motivations to participate in conservation management of such systems may continue to weaken and abandonment may therefore become a significant risk to the successful conservation of such systems. Conservation stakeholders need to foster good relations with their farmer-manager partners and not further depress their limited motivations to participate, as well as consider carefully whether farmer stakeholders are being adequately compensated for their efforts.     

Multiple regression models for the lower heating value of municipal solid waste in Taiwan

A multiple regression analysis was used to develop two predictive models of lower heating value (LHV) for municipal solid waste (MSW), using 180 samples gathered from cities and counties in Taiwan during 2001-2002. These models are referred to as the original proposed model (OPM) and the simplified model (SM). The coefficients of multiple determinations for the OPM and SM were 0.983 and 0.975, respectively. To verify the feasibility of the models, a demonstration program based on sampling of MSW in Kaohsiung City was conducted. As a result, the OPM showed superior precision in terms of relative percentage deviation (RPD) and mean absolute percentage error (MAPE), when compared to the conventional models based on the proximate analysis, physical composition and ultimate analysis. The SM was derived by neglecting the three minor physical components used in the OPM. The resulting SM was less precise when compared to the OPM, but it was still acceptable, with a precision level better than the conventional models. It was concluded that the predictability of empirical models could be improved significantly through selection of the appropriate physical components and multiple regression analysis.     

连续型超临界水氧化系统出水酸碱性分流试验研究

在用连续型超临界水氧化设备处理废水时,经常发现系统的净化出水pH值变小、排盐出水pH值变大。为了深入研究并揭示其机理,选择原碱性废水中和水、原酸性废水中和水、弱碱性废水、NaCl水溶液、纯自来水和纯NaOH水溶液6种典型水样进行定量试验。结果表明,连续型超临界水氧化系统存在净化出水和排盐出水pH值变化的现象,即使废水在进入系统前调整为中性(pH=7),反应后依然是净化出水pH7,排盐出水pH7。该现象很可能是由于在超临界状态下原水中无机酸根离子和金属阳离子的结晶盐离解生成了H~+、OH~-,随后各自缔合成酸性和碱性物质。缔合的酸性物质留在超临界水中,并随之从净化水出口排出,降低了出水的pH值;缔合的碱性物质混入盐结晶析出物中,随之在亚临界区溶解并经过排盐口流出,而重新溶解的金属氢氧化物增加了排水的pH值。另外,在超临界水氧化反应器复杂的氧化腐蚀环境下也生成了一定量的OH~-和酸缔合物,它们对改变出水pH值有一定作用。酸根离子极难从超临界水氧化系统中分离,因此对碱性废水要慎重中和,特别要慎重选择酸根离子,最好不要用盐酸中和,这是因为其带入的Cl~-会引起超临界系统内的氯腐和系统净化出水口的酸腐。研究表明,因为存在出水pH值的变化,对超临界水氧化系统出水的纯净程度必须予以重新考虑。     

数值模拟在群桩基础评判标准确定中的应用

群桩基础安全稳定性评判决策中各因子评判标准边界的确定是保证其模型正确构建的关键环节。由于安全监测系统无法测得这种警戒值,因此,本文采用基于ABAQUS软件的数值模拟方法,依据上部结构受力特点及使用要求来确定群桩基础安全稳定性判别决策因子的警戒值。仿真结果显示:该方法能可靠获取超大型深水群桩基础成桥后的基桩轴力不均匀性和差异沉降的最佳警戒值。     

基于优化组合赋权的煤层气开发风险评价研究

煤层气开发项目的高风险制约着我国煤层气产业的发展,为此,通过对煤层气开发风险因素的分析,基于煤层气开发特征构建由7个一级指标和34个二级指标构成的风险评价体系。运用离差平方和优化组合熵值法和三角模糊数法所得权重确定指标最佳权重,建立煤层气开发风险评价模型。最后,以沁水盆地南部柿庄南区块煤层气井为例进行实证评价,结果显示地质资源因素对该地区煤层气开发影响最大,其中渗透率的影响最为显著。研究表明:模型能优化主观评价和客观评价的赋权比重,最大化的减少主观因素对评价结果的影响,能客观合理的表达多指标间的对比差异,对煤层气开发风险进行可靠的定量化评价。为煤层气开发风险的控制和规避提供科学的理论依据。