基于Gompertz的气象水文装备维修器材消耗量分析与预测

利用由Gompertz曲线推导出的生命周期曲线建立了气象水文装备维修器材消耗-时间模型.计算表明,由Gompertz曲线推导出的生命周期曲线可以较好地反映气象水文装备维修器材消耗量与时间之间的关系,所建模型的预测结果也较好,具有较高的实用性,为探索气象水文装备维修器材消耗规律提供了一种简单有效的科学方法.     

Ti/Sb-SnO2功能电极的制备及电化学处理废水的性能

采用热分解法制备了Ti/Sb-SnO2电极,并用XRD、SEM对电极涂层进行表征.研究了涂层次数对于析氧过电位的影响,应用阳极快速寿命测试法测试了Ti/Sb-SnO2电极的使用寿命,通过极化曲线考察了电极的析氧过电位.采用该电极对甲基橙模拟废水进行了电化学降解实验,并考察此电极处理实际废水的效果.研究表明,随着涂层次数...     

武汉城市圈产业结构动态分析

武汉市作为国家“两型社会”改革试点城市圈之一,又是武汉城市圈的龙头城市,在面临东部产业转移和国家积极调整产业结构的背景下,一方面必须积极承接东部转移产业,另一方面又必须调整产业结构,以保证经济的可持续发展.基于前人的研究,对武汉城市圈9个城市的三次产业发展情况进行区位熵分析,并结合武汉城市圈整体产业结构的洛伦兹曲线和基尼系数分析得出武汉城市圈9个城市的产业结构现状,以及在各个产业上的比较优势和产业结构相似性的情况,在武汉城市圈面临迎接产业转移和自身产业结构调整双重任务的前提下,结合可持续发展模式对武汉城市圈产业布局优化和产业结构调整提出政策建议.     

A Method to Assess and Define Environmental Flow Rules for Large Jurisdictional Regions1

Snelder, Ton, Doug Booker, and Nicolas Lamouroux, 2011. A Method to Assess and Define Environmental Flow Rules for Large Jurisdictional Regions. Journal of the American Water Resources Association (JAWRA) 47(4):828‐840. DOI: 10.1111/j.1752‐1688.2011.00556.x Abstract: Hydrological rules of thumb are used across jurisdictional regions to set minimum flows and allocation limits that apply by default (i.e., when more detailed site‐scale studies have not been carried out). Uniform rules do not account for spatial variation in environmental characteristics, resulting in inconsistent consequences for the protection of ecosystems, and the reliability of water resources. We developed a method for assessing hydrological rules of thumb that describes their consequences for protection of the ecosystem (in terms of retention of physical habitat) and the reliability of the water resource. The method links regionalized flow duration curves, at‐station hydraulic geometry, and generalized physical habitat models to make assessments at many locations across a region. The method estimates, for a given set of rules, the retained physical habitat for specified taxa/life stages and the proportion of the time abstractions are restricted. We applied the method to assess a set of rules that are proposed as default minimum flows and allocation limits for New Zealand rivers. The assessment showed that the minimum flow rules had variable consequences. The method could be used to quantify the tradeoff between environmental protection and water resources availability and reliability.     

足尺钢桁架连梁恢复力模型试验研究

对4个足尺的钢桁架连梁模型进行了低周反复荷载试验,研究了结构的破坏形态、滞回性能。利用试验数据进行回归分析,建立了骨架曲线恢复力模型;对滞回曲线进行了分析,研究了连梁的刚度退化规律,建立了循环荷载作用下结构的恢复力模型。模型和试验曲线较为吻合,可用于结构的弹塑性分析。     

钢铅组合防屈曲支撑的滞回性能与参数研究

为简化防屈曲支撑的加工工艺,提高防屈曲支撑的初始刚度和在小变形下的耗能能力,基于现有防屈曲支撑在截面形式与构造方式上的特点,提出了一种新型钢铅组合防屈曲支撑并进行了构造设计。通过有限元数值模拟,分析了钢铅组合防屈曲支撑的耗能特性与效果,建立了恢复力简化模型,并根据理想弹塑性材料本构关系推导出滞回规则。通过对不同设计参数的理论分析和数值模拟,分析了钢铅屈服力比、铅剪切面长宽比、核心段宽厚比和耗能段长度等参数对防屈曲支撑滞回性能的影响。研究结果表明,钢铅组合防屈曲支撑能够提供较大的抗侧刚度,耗能效果良好,加工工艺简单,适合工程应用。     

金属压力容器水压试验声发射检测

通过对容积为504．94m3的某型号压力容器出厂前水压试验的声发射检测,分析了其在升压和保压过程中的声发射信号特征及其来源。结合AE信号参数、波形及定位图分析,对该容器进行了声发射活性评价,确定需要后续复检的强活性区域。文章为压力容器的声发射检测和安全评价提供了理论指导和参考数据。     

Theory of storage,inventory and volatility in the LME base metals

The theory of storage, as related to commodities, makes two predictions involving the quantity of the commodity held in inventory. When inventory is low (i.e. a situation of scarcity), spot prices will exceed futures prices, and spot price volatility will exceed futures price volatility. Conversely, during periods of no scarcity, both spot prices and spot price volatility will remain relatively subdued. We test these predictions for the six base metals traded on the London Metal Exchange (aluminium, copper, lead, nickel, tin and zinc), and find strong validation for the theory. Including Chinese inventories reported by the Shanghai Futures Exchange strengthens the relationship further. We also introduce the concepts of excess volatility, inventory-implied spot price and inventory-implied spot volatility and illustrate some applications.     

Estimation of Daily Streamflow of Southeastern Coastal Plain Watersheds by Combining Estimated Magnitude and Sequence

Commonly used methods to predict streamflow at ungauged watersheds implicitly predict streamflow magnitude and temporal sequence concurrently. An alternative approach that has not been fully explored is the conceptualization of streamflow as a composite of two separable components of magnitude and sequence, where each component is estimated separately and then combined. Magnitude is modeled using the flow duration curve (FDC), whereas sequence is modeled by transferring streamflow sequence of gauged watershed(s). This study tests the applicability of the approach on watersheds ranging in size from about 25‐7,226 km² in Southeastern Coastal Plain (U.S.) with substantial surface storage of wetlands. A 19‐point regionalized FDC is developed to estimate streamflow magnitude using the three most selected variables (drainage area, hydrologic soil index, and maximum 24‐h precipitation with a recurrence interval of 100 years) by a greedy‐heuristic search process. The results of validation on four watersheds (Trent River, North Carolina: 02092500; Satilla River, Georgia: 02226500; Black River, South Carolina: 02136000; and Coosawhatchie River, South Carolina: 02176500) yielded Nash‐Sutcliffe efficiency values of 0.86‐0.98 for the predicted magnitude and 0.09‐0.84 for the predicted daily streamflow over a simulation period of 1960‐2010. The prediction accuracy of the method on two headwater watersheds at Santee Experimental Forest in coastal South Carolina was weak, but comparable to simulations by MIKE‐SHE.     

高压密封消化罐测定COD_(Cr)

采用高压密封消化罐代替聚四氟乙烯生料带密封具塞磨口比色管,进行密封法测定废水中COD_(Cr)的研究.该法与原通用的标准法和文献介绍的密封法相比,不仅在密封压力条件下.较好地抑制氯离子的氧化,并具有试剂用量少,费用低、省水、省电、准确度高,减少二次污染,适于批量分析等优点.