A practical estimation of Clark IUH parameters using root selection and linear programming

The values of the parameters of the Clark instantaneous unit hydrograph (IUH) are often relying on the subjective decision of the researcher, which leads to large variations of their values. Therefore, an objective method minimizing the subjective judgement in the IUH modelling procedure while providing a reduced range of acceptable values is proposed. The proposed method uses a basin average IUH to mitigate the robustness problem of the Clark IUH parameters. Using linear system theory, the z‐transform is applied to the average IUH and then the IUH polynomial is factored into the recession and time‐area curve (TAC) components based on a convolution relation between the Clark IUH parameters. During this calculation, the root selection method was adopted to verify the storage coefficient R from the recession component and a linear programming technique was applied for determining the TAC for the basin of interest. The Wi River basin was used to test the applicability of the proposed method. The results showed that the components of a single reservoir and the TAC for Clark IUH were separated effectively, and acceptable values for the parameters were obtained. Copyright © 2011 John Wiley & Sons, Ltd.     

HPFL条带加固眠墙抗剪试验研究

为了了解高性能水泥复合砂浆薄层(High Performance Ferrocement Laminate,简称HPFL)加固低强度眠墙的抗震性能,本文通过1片未加固眠墙和4片采用HPFL条带加固的眠墙的水平低周反复荷载试验,对比研究了各个墙片的抗震性能.试验结果表明,用HPFL条带加固后的眠墙显著提高了其开裂荷载和极...     

鄂西地区坚硬“打滑”地层钻进方法

在鄂西地区磷矿、铅锌矿、银钒矿赋矿地层及上覆地层中,普遍存在着坚硬岩层。震旦系白云岩中含大量的硅质层和经化学沉积形成的＂玉髓＂层,硅质含量超过80%,并且结构致密,呈弱研磨性,岩石可钻性达到Ⅸ～Ⅹ级。通过钻探现场生产试验,从金刚石钻头选型、人工修磨钻头方法、金刚石钻进工艺参数选择等几个方面总结了生产实践中取得的成功经验,为今后进一步解决钻进打滑问题提出了思路。     

遥感影像尺度转换及最优尺度选择探讨

从信息提取的角度阐述遥感影像尺度问题的重要性,评述了尺度效应、尺度转换以及最优尺度选择研究的国内、外现状。重点探讨几种不同尺度转换方法,以及基于像元和面向对象的最优尺度选择方法的技术特点,分析了尺度研究未来发展方向。     

Assessing waterbird habitat use in coastal evaporative systems using stable isotopes (δC, δN and δD) as environmental tracers

Isotopic patterns of biota across salinity gradients in man-made evaporative systems could assist in determining the use of these habitats by animals. Here we report δ¹³C, δ¹⁵N and δD measurements of a euryhaline fish, the Mediterranean toothcarp (Aphanius fasciatus), inhabiting a range of salinities in the Thyna saltworks near Sfax (Tunisia). The contribution of these salinity niches to egg formation of two typically piscivorous bird species breeding in the area and feeding within saltworks, Little Tern (Sternula albifrons) and Little Egret (Egretta garzetta), was inferred trough a triple-isotope (δ¹³C, δ¹⁵N and δD) Bayesian mixing model. Isotopic trends for fish δ¹⁵N and δD across the salinity gradient followed the equations: δ¹⁵N = e^{(1.1 + 47.68/Salinity)} and δD = −175.74 + Salinity + Salinity²; whereas fish δ¹³C increased as salinity rose (δ¹³C = −10.83 + 0.02·Salinity), after a sudden drop in fish isotopic values for salinities >60 (Practical Salinity Scale) (average fish δ¹³C for salinities <60 = −5.92‰). Both bird species fed largely on low hypersalinity ponds (salinity = 43; average contribution = 37% and 22% for Little Egrets and Little Terns, respectively), although the use of intermediate hypersalinities (salinities 63 and 70) by Little Terns also occurred (16% and 21%, respectively). Isotopic patterns across salinity gradients allow the use of isotopic measurements to inform studies of habitat occupancy within evaporative systems and provide further insights into how wildlife communities interact with them.     

波浪能发电装置海上选址的分析研究

海上选址是波浪能发电装置进行现场试验以及电站投产建设的基础工作,是装置正常运行的先决条件。文章基于层次分析法原理,对波浪能发电装置海上选址的影响因素进行分析,将选址问题的定性分析转化为定量计算,通过计算找出最优的选址方案,为波浪能发电装置海上选址提供了科学的决策依据。     

集成不同类型特征的城市道路选取方法研究

道路选取是进行道路网地图综合及多尺度表达时的基础。现有的道路选取方法大多是以道路的语义特征和几何特征作为道路选取的依据,较少考虑道路的拓扑特征。基于此,该文以城市道路网为例,综合考虑道路的语义特征、几何特征和拓扑特征,并以道路综合性能作为城市道路选取的依据,提出一种城市道路选取的新方法。通过实例分析,验证了该方法的有效性。     

塔里木盆地西北缘埃迪卡拉纪—寒武纪转折期黑色岩系中硅质岩成因及其环境指示意义

埃迪卡拉纪—寒武纪转折期是地质历史上的关键期,全球范围内普遍发育一套黑色岩系,包括硅质岩、泥岩和白云岩。在这套黑色岩系中下部,发育了不同厚度的硅质岩,尤其是在塔里木盆地西北缘,黑白燧石条带韵律性互层且硅质岩分布变化大,其成因对寒武系玉尔吐斯组优质烃源岩形成环境具有重要指示意义。本文以塔西北地区新柯地1井这套黑色岩系中硅质岩为研究对象,运用岩芯观察、镜下薄片鉴定、主微量元素和稀土元素分析,研究硅质岩与有机质的成因及其二者之间的共生机理,硅质岩较高的Ti、V、Y、Ba等元素含量、较低的δ30Si值(1. 2‰~0. 7‰)、明显的Ce负异常说明其硅质流体为热液来源,但是硅质岩不是热液脉体侵入形成,而是富含硅质的流体与冰冷的海水混合沉积而成,硅质岩沉积受温度、pH值、有机质等因素共同控制,有机质的存在可以促进硅质沉淀。同时系统地研究了黑白燧石条带韵律性互层的成因,白色层由纯的微晶石英组成,而黑色层由碎屑碳质颗粒、石英颗粒和碳质纹层组成,认为是微生物席活动的结果,硅质岩中黑白燧石层受冰期和间冰期控制。硅质岩中较高的Al2O3/(Al2O3+Fe2O3)比值和较低的Lan/Cen比值代表受陆源影响的大陆边缘沉积环境,结合古气候、海平面变化等信息,认为塔西北地区寒武系玉尔吐斯组硅质岩以及硅质页岩沉积于局限海湾或潟湖环境,为正确认识硅质页岩的形成环境和烃源岩的评价预测提供理论指导。     

基于SPI软件计算模块的开发与应用

本文对SPI软件计算模块的开发与应用进行了研究,主要介绍了工艺条件数据自动导入SPI软件的方法与计算模块的应用,并以调节阀的计算为例,同其他计算软件的计算结果进行对比分析,验证了计算模块计算结果的正确性与有效性,提高了设计质量与设计效率。     

山前带砾石区激发技术优化

复杂山前带是油气勘探的重要领域,具有良好的成藏条件,但由于其复杂的地表、近地表及复杂地下构造,造成该地区地震资料信噪比低,成像精度差。基于山前带砾石区的激发特点,笔者认为在山前激发点选取过程中可借助Google Earth平台进行点位设计,在激发点选取时应采取避高就低、避砾就岩、避陡就缓的原则;小排列层析反演技术能较好地结合小折射和微测井优点,适用于山前表层调查;井深设计时应尽量选择在速度较高、激发能量较强、激发频率高的介质中激发。ZD地区的采集资料显示,采用山前砾石区激发方式能较好地改善地震资料品质。