近44 年关中夏季分级雨日及降水量的变化特征

[目的]通过对关中地区夏季雨日(量)进行分级研究,更深入地了解关中夏季降水变化特征及各级雨日(量)对关中夏季降水变化的贡献大小。[方法]利用1970~2013年关中地区44个气象站逐日降水资料,采用趋势分析法,Mann-Kendall检验,t-检验和GIS技术等方法对关中夏季不同等级雨日和雨量变化特征进行分析。[结果](1)关中多年平均夏季雨日空间分布均为西多东少,西北部塬区和山区丘陵多于平原,各等级雨日和对应雨量空间分布特征及变化趋势相似。(2)近44年关中夏季总雨日、小雨日(量)和大雨日(量)均呈减少趋势,夏季降雨总量、中雨日(量)和暴雨日(量)均呈增加趋势,但线性变化趋势均不显著。其中小雨日(量)和大雨日(量)分别在1989年和1985年发生突变性减少,中雨日(量)在1978年发生突变增加。(3)单站分析表明关中夏季总雨日除咸阳大部外多数呈负趋势,夏季降雨量除渭南大部外普遍为正趋势。其中大部分站点小雨日(量)和大雨日(量)为负趋势,减少显著的站点分布在宝鸡地区;中雨日(量)和暴雨日(量)普遍为正趋势。[结论]夏季总雨量的增加主要贡献者是中雨量增加,总雨日减少主要是小雨日减少引起。从长期趋势变化看,关中夏季降水强度有增加趋势。     

1961—2020年宁夏地区极端气候变化趋势及影响因素分析

目的 探明极端气候指数的时空变化特征,明确极端气候变化的影响因素。方法 文章基于1961—2020年宁夏19个气象站点的逐日平均气温、最高气温、最低气温和降水量等数据,采用国际气候诊断与指数小组（ETCDD－MI）定义的极端气候指数,运用线性趋势法、克里金插值法、小波分析等方法,明确宁夏极端气候变化趋势,并探讨人类活动与极端气温变化的关系。结果 （1）宁夏的极端气温指数中,暖夜、夏日日数、持续暖期日数和年最大日最高气温均呈现上升趋势;霜冻日数、冷昼、持续冷日日数均呈现下降趋势,年最大日最低气温呈上升趋势。（2）在空间分布上,暖夜、夏日日数、连续暖期日数和年最大日最高气温的变化率在引黄灌区变化率较大,指数均呈现上升趋势,霜冻日数、冷昼、连续冷期日数在全区均呈现下降趋势,引黄灌区和中部干旱区下降趋势变动较为明显。（3）极端高温指数的变化率在北部引黄灌区较高,全区呈现出升温态势。（4）宁夏4个极端降水指标变化并不显著,但区域间年际变化差异较大,南部山区大部分地区极端降水指数变化率较高且呈正向变化,而北部引黄灌区降水年际变化率远低于南部山区且降水趋于减少。（5）1987—1992年极端高温指数和极端低温指数存在显著共振周期,极端高温指数上升领先极端低温指数。（6）极端气温影响因素分析发现,人口的增长、能源消费碳排放量的增加、城市化率的上升和建筑面积的增加,与月最高温日值都存在线性相关关系,反映出随着人类活动的增加,极端高温指数也存在一定程度的正向关系。结论 极端气候变化特征表明,宁夏地区高温事件增加,低温事件减少,极端降水年际波动幅度较大,地区差异显著,并且人类活动可能与极端气候变化存在相应关系。     

中药材初加工废水处理工程设计与运行

针对亳州某产业园中白芍初加工废水,包括清洗废水和蒸煮脱皮废水,其中白芍清洗废水处理采用“旋流沉砂器+平流沉淀池”工艺,白芍蒸煮脱皮废水处理采用预处理和“UASB+A/O+混凝沉淀(保障工艺)”工艺,并考察其运行效果。结果表明:清洗废水经处理后出水水质可以达到清洗回用标准,使废水可循环再利用;蒸煮脱皮废水处理后达标排放,出水水质满足《中药类制药工业水污染排放标准》(GB21906-2008)中污染物最高允许排放浓度的一级标准。该废水处理工程运行稳定、出水达标,可为同类工程设计提供参考。     

电厂干除灰改造方案技术经济分析

随着国家对清洁生产、循环经济的重视，双源公司从建设节约环保型企业和降低检修维护量的角度出发，对除灰系统进行了正压浓相气力输灰优化。介绍了双源公司气力除灰系统改造方案和技术经济分析。     

某大厦基坑边坡支护与降水设计

深基坑施工是建设地下停车场的首要工程,如何才能保证基坑的稳定及基坑周边环境的安全,已成为基坑工程设计、施工中的难点和重点。本文作者某大厦基坑开挖工程实例,主要就大口径井点降水设计及钻孔灌注桩边坡支护设计的过程进行了阐述。     

Competitive Storage,Biofuels and the Corn Price

The use of corn as an ethanol feedstock has been stimulated by US biofuels policy. This has changed both the position and the slope of the corn demand curve and increased the pass-through from crude oil to corn prices. The principal constraints on ethanol consumption and production have been regulation (the biofuels mandate), capacity constraints in ethanol refining and the blend wall, which puts a ceiling on the ethanol content of gasoline. The incidence of these constraints has varied over time. We model these impacts within the competitive storage model using structural break regression analysis. Our analysis shows that the pass-through has varied over time in relation to the share of ethanol in total US corn use. Our analysis provides robust empirical evidence of an increase in the pass-through from crude oil to corn prices over the period from the start of the century to a high level over 2004–2008 when corn use in ethanol was growing very fast. This enhanced sensitivity was driven by competition for corn as an ethanol feedstock with stock demand exerting strong upward pressure on the corn price.     

基于某工程的井点降水研究

随着建筑物开挖深度越来越深,对于基坑开挖过程中的降水也提出了越来越高的要求。本文结合某工程成功的工程实例作简要介绍。     

Critical Areas and Entry Points for Sustainability‐Related Strategies in the Sugarcane‐Based Ethanol Industry of Brazil

This study reveals five critical areas that Brazil's sugarcane‐based ethanol industry could capitalize on to incorporate sustainability into their firms' strategies. The emergent theoretical framework represents a starting point for further investigations aimed at integrating the sustainability construct and strategies for the industry. A growing body of literature calls for strategic management to adapt to complex and ever‐changing environments and sustainability trends. For many firms in developing economies, sustainability remains isolated from mainstream strategy, resulting in reactive approaches on the part of management. A qualitative research method – grounded theory – was used to induct from data. Five themes emerged from the analysis providing guidance on where sustainability‐related strategies ought to begin. This research posits that existing sectoral innovation systems could be used to channel sustainability‐driven innovations. In addition, a combination of public and private efforts to foster innovations based on the emergent themes could increase the value of industry under study, while lessening its social and environmental footprint. Copyright © 2012 John Wiley & Sons, Ltd and ERP Environment.     

钼酸铅重量法中沉淀条件和提高沉淀纯度的探讨

对影响钼酸铅晶形沉淀生成时的乙酸铅(沉淀剂)浓度、加入速度、溶液的温度和体积、沉淀的陈化时间和洗涤剂的浓度进行了探讨,确定了沉淀条件。