共查询到20条相似文献,搜索用时 171 毫秒
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介绍了一种利用单二极管5个参数的光伏组件模型估算光伏组件参数的方法,该方法不需要其他额外数据,仅利用光伏组件铭牌中的参数就可以计算光伏组件的相关参数。首先把标准测试条件(STC)下的光伏组件电气方程中的5个参数等量代换为2个参数,然后通过构建最小二乘目标函数法在特定范围内进行扫描优化确定2个参数的值,最后利用STC条件下的单二极管5参数电气模型确定其他参数;同时也构建了NOCT条件下组件的全参数模型。该方法易于实施且能够避免收敛问题,从光伏组件的分析结果来看,该方法能够精确估算组件的参数。 相似文献
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本文对涡轮增压器的主要部件——离心式压气机在变工况下的流量特性、效率特性的计算进行了探讨,并分析了在喘振线上一些参数的变化规律。1)性能计算是基于理想气体一元定常流动的假设之上的。用质量守恒、能量守恒等基本关系式推导出有关计算公式,并通过计算比较,确定了适当的损失模型。在已知有关几何参数的条件下,将带无叶扩压器的离心式压气机依工质的流程划分为5个计算站位,依次计算各站位上的热力参数,最终求出流量、效率特性。按上述计算方法与步骤编制了计算程序,在计算机上对数种型号的离心式压气机进行了计算。主要输入参数有:各计算站位的流道截面积、叶轮进出口叶片构造角等几何参数;大 相似文献
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Market-based pollution control mechanisms such as pollution levy and cap and trade have received increasing attention from both academics and practitioners. A good understanding of the optimal pollution price under these mechanisms is a premise for regulators to make sound pollution control policies. In this paper, we propose a method for deriving the optimal pollution price for a given pollution target. This method consists of two steps that integrate cost function estimation and market equilibrium analysis: First, historical data is used to estimate the pollution abatement cost functions of the polluters; second, market models are used to solve the equilibrium pollution price under each control mechanism. For illustration, we apply the method to investigate SO2 emission control policies in China, using a dataset of SO2 emissions and abatement costs from three major industry sectors (Electricity, Gas, and Water Supply; Manufacturing; and Mining). Our analysis shows that the optimal levy rate is significantly higher than the actual rate adopted by the Chinese government. For example, the optimal levy rate should be 4.92 RMB/kg, while the actual rate is 1.26 RMB/kg in 2010. As a result, the actual emission structure is much less efficient: The overall cost savings would be 49.7% for all three sectors during 2006–2010 if the optimal emission structure is achieved. These findings have useful policy implications for the Chinese government. In addition, the method may be applied to analyze control policies at different aggregate levels (for example, provincial economies) or for other pollutants (for example, CO2 and chemical oxygen demand). 相似文献
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Multicriteria assessment of natural ventilation potential 总被引:3,自引:0,他引:3
A method is proposed to assess the natural ventilation potential by taking into account the most comprehensive set of factors involved in natural ventilation. These factors are either driving forces, such as wind pressure and stack effect, or constraints, like noise pollution and atmospheric pollution. The process considers these factors in an ordinal qualitative scale and gives its result in that scale.This bypasses the problem of the inaccuracy of some parameters, which can be very high, especially in urban environment and in the pre-design phase of a construction project. Actually, the method is particularly suitable for designers intending to take early-stage decisions. 相似文献
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鉴于污染价值损失的核算对掌握流域水污染状况、制定科学合理的治理对策具有重要意义,通过分析污染物浓度跟水资源价值损失的关系,将水量、水质和水资源价值三者结合起来,从理论上构建了基于污染损失率和水资源价值的污染价值损失模型,且给出了完整的水污染经济损失量的数学表达式,并将其应用于许昌市清潩河流域水污染经济损失核算中。结果表明,清潩河流域水环境污染的经济损失在2011~2014年间呈现波动变化,2013年污染损失量最大,达到7 365.41万元。三个行政分区中,2011~2012年间长葛市水污染损失量最大,2013~2014年间许昌县水污染损失量最大,与当地的实际情况相符。可见该模型可行、有效。 相似文献
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叶片参数化是叶轮机械气动优化过程中十分重要的一个环节,它决定着叶片的气动优化空间。传统叶片是通过叶片几何或特征来实现参数化,很少利用气动参数来实现。为了解决该问题,提出一种基于气动参数的三维叶片参数化方法,该方法通过经验公式将气动参数引入叶片参数化过程,并利用几个重要截面中的两条重要特征曲线(中弧线和厚度分布曲线)实现叶片重构。通过对实际叶片进行参数化可以发现:参数化后叶片与原始叶片之间的几何相对误差最大不超过0.01;两者表面压力系数变化趋势基本一致。因此,该方法不仅能够准确描述三维叶片形状,还将气动参数直接设置为优化控制变量,从而有利于优化效率的提高。 相似文献
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长潭水库富营养化评价及防治对策 总被引:1,自引:0,他引:1
针对近年来长潭水库水质的富营养化现象,分析了三个常规监测断面2007~2011年间各项水质指标年际变化趋势,利用水库营养状态评价标准及分级方法对长潭水库水质的营养水平进行评价,得出其水体现状为中营养状态,水质变化的主要原因为上游来水携带的污染物,尤其是农业面源污染是造成水体富营养化的主导因素,并从控制污染源及清除底泥等方面提出相应的解决措施。 相似文献
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为探究白城市地下水污染程度及污染现状,基于28个潜水水质监测井的监测数据,运用对应分析法分析了氨氮等8个主要污染指标,并利用改进的TOPSIS评价法和模糊综合评价法分析了潜水水质情况,将综合结果用GIS绘制成相关图件,以探究不同污染因子富集的原因。结果表明,研究区地下水按主要污染指标分为3个区域,各区地下水分别受到NO-3,氨氮、铁锰及氟化物,Cl-和SO2-4的影响;白城市地下水普遍较差,近40%的监测井受到污染或轻度污染,其中自然和人类活动的双重影响是研究区地下水污染的主要原因。这说明结合两种方法可以更加全面地分析水质现状,为研究区地下水污染防治提供依据。 相似文献
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Today, energy has become one of the most important concerns of developing countries. The use of non-renewable energy sources, as well as the production of pollution, has led to growing efforts to replace fossil fuels, which are the most important energy sources in the modern world. Hydrogen as a clean fuel has attracted a lot of attention in recent years. Various methods have been reported for the production and storage of hydrogen. According to their advantages and disadvantages, it can be said that electrochemical hydrogen storage method is superior to other methods in terms of cost, safety, and optimum condition. The electrochemical hydrogen storage is done in a variety of techniques, and in recent years, the chronopotentiometry method has become one of the most popular methods for scientists. In chronopotentiometry technique, several parameters such as the reference electrode, the counter electrode, the working electrode, electrolyte, and current density are important. In this review, we investigated the articles that have been done in this regard from 2000 to 2020. This review can help scientists to better understand the electrochemical hydrogen storage system. 相似文献