近期长江荆江河道演变特点

从长系列资料看,上游来水量无趋势性增大或减少,来沙量自20世纪90年代以来明显减少.入洞庭湖三口分流分沙呈减少趋势,尤其以藕池口衰减最为突出. 1998年大水造床作用明显,上荆江滩槽皆冲,以冲滩为主;下荆江表现为冲槽淤滩,总体呈淤积状态.还对重点河弯,如沙市、石首河段,自1998年大水以来的最新演变情况作了详细分析,主要特点表现为沙洲移动、主流线摆动,顶冲点普遍下移,崩岸时有发生.     

Synergies of scale: A vision of Mongolia and China's common energy future

Energy consumption in China is expected to double over the next 20 years. Addressing the enormous scale of China's energy need and attendant increases in greenhouse gas emissions requires dramatic and rapid rollout of renewable energy technologies. Mongolia has some of the world's best renewable energy resources but the scale of its market cannot tap them efficiently. Developing Mongolia into a significant exporter of renewable energy to China will create synergies of scale moving both countries towards their energy goals, creating jobs, and fostering growth while significantly reducing GHG emissions in the region.     

Kinetics of emitted mass—A study with three dry powder inhaler devices

The purpose of this study was to understand the kinetics of emptying of micronised salbutamol sulphate (SS) and lactohale 300 (LH300) under varying air flow rates (30–180 L min⁻¹) from three dry powder inhaler devices, Rotahaler^® (RH), Monodose Inhaler^® (MI) and Handihaler^® (HH). Aerosol concentration vs. time profiles, determined through real-time laser diffraction particle sizing, demonstrated that the majority of the powder from RH was emitted within one second while a more prolonged aerosolisation was observed from MI and HH. Peak aerosol concentrations were achieved more rapidly from RH compared to MI for both SS and LH300. Calculated cumulative emitted mass (CCEM) vs. time profiles were obtained from the aerosol concentration vs. time profiles and the emitted mass and the rate of CCEM (k_CCEM), estimated from a modelling approach, increased with increasing air flow rates. The k_CCEMvs. air flow rate profiles of SS and LH300 were significantly different at high air flow rates. The k_CCEM was highest from RH and lowest from MI. Differences in k_CCEM between the devices were related to capsule aperture size while the differences between the materials were due to the powder bed structure. This approach provided an understanding of the rate at which powder mass emptied from dry powder inhaler devices and was proposed to be a powerful development tool for the future powder inhalers.     

提高大位移井固井质量方法

分析了大位移井固井的技术难点,从水泥浆的体系、套管的居中、附件的优选与应用、现场施工技术等方面进行了研究,提出了保证大位移井固井质量的技术措施,现场实践取得显著效果,形成了系统、成熟的大位移井固井技术.对大港油田大位移井固井质量的提高具有指导作用.     

QK17-2大位移井的井眼净化研究

井眼净化是大位移井中的一项关键技术,井眼净化不好易导致黏附卡钻等多种问题的发生。在考虑钻井液性能、钻具旋转、机械钻速等因素的基础上,设计了QK17-2-P33大位移井中岩屑滚动运移和悬浮运移的最小环空返速及临界排量,分析了实钻过程中QK17-2-P30大位移井的基本情况及QK17-2-P31井钻井过程中由于井眼净化不好而导致卡钻的原因,为今后大位移井的井眼净化提供了借鉴。     

遥感监测调水调沙对黄河河口尾闾的影响

调水调沙是治理黄河的重要措施,遥感技术是监测调水调沙效果的重要手段.通过对3次调水调沙试验中黄河河口遥感数据的分析,定量描述了黄河河口尾闾淤进蚀退,并将黄河利津水文站的观测资料作为佐证,初步揭示了黄河河口淤进蚀退与上游来水来沙量的关系,说明了调水调沙对黄河河口尾闾的积极作用.     

抛物线型井眼轨道的数学模型及其设计方法

井眼轨道设计是实现定向钻井的首要环节。下部钻柱比较符合抛物线的力学模型,所钻出的井眼轨迹更接近于抛物线,因此将井眼轨道设计成抛物线具有理论依据。抛物线剖面设计的实质是确定抛物线井段的形状和位置,抛物线的特征参数P决定了其形状,而抛物线井段的起至井斜角或后续稳斜井段的段长等参数决定了抛物线井段在井身剖面中的位置。系统地阐述了抛物线轨道的力学模型和数学模型,分析了抛物线剖面的特征参数和设计条件,提出了2种抛物线剖面的设计方法——迭代法和直接法。在相同的条件下,这2种方法的设计结果是相同的,可以相互验证。但是,直接法不需要进行迭代计算,设计条件具有较好的可操作性,便于推广应用。通过对抛物线剖面的优化设计可以降低摩擦阻力和摩阻力矩,有利于减少钻柱和套管的磨损;可以改善钻柱的受力状况,减轻钻柱的疲劳破坏、减少产生键槽的几率;可以施加高钻压连续钻进,有利于提高机械钻速。     

大位移井钻井技术风险评价与分析

提出了大位移井钻井技术风险的多因素综合评价方法,以功效评价系数体系建模,并实现了对该模型的求解.文中系统研究了功效评价系数体系,为建模提供了科学依据.所建立的风险评价模型,阐明了多因素与风险的关系.通过对典型实例的分析,说明本文方法切实可行,有助于大位移钻井技术风险评价与防范,并为工程师提供了一个便于操作的风险评价定量化模型.     

弯道推移质泥沙运动特性及其对河道演变的影响

弯曲河道水流、泥沙的运动特性与顺直段不同 ,存在横向流速与横向输沙。在考虑了弯道河段横向水流影响的条件下 ,导出了弯道河段泥沙的起动流速公式 ,并进行了合理性分析 ,认为在相同的纵向流速条件下 ,弯道段凹岸侧泥沙的起动粒径和泥沙输移速率均较顺直段大。同时结合弯道段水流和泥沙的运动特性阐明了弯道河段的演变规律。     

二维泥沙数学模型在赣江大堤南昌段改线中的应用

采用平面二维水流泥沙数学模型计算了赣江大堤南昌段堤线改线对河段水流运动及河床冲淤的影响。在运用实测资料对该数学模型进行河段水面线，断面流速分布，汊道分流比和河床冲淤分布验证的基础上，计算了堤线改线工程前，后河段洪水水位壅高，断面流速分布变化，取土料场回淤等。