缝洞型油藏离散介质网络数值试井模型

针对多重介质试井模型不符合缝洞型油藏网络状分布、非均质性极强的地质特征,建立了新的试井模型,将大尺度溶洞（流体主要的储集空间）视作零维模型,裂缝、孔洞发育的条带状地层（沟通溶洞的渗流通道）作为控制流体流动的一维模型,从而构成离散介质网络（DMN）模型。用有限差分法建立了缝洞型油藏离散介质网络油水两相数值试井模型,对渗流通道的储渗性能、大尺度溶洞的容积和距测试井的距离等因素对测试井压力响应特征的影响进行了研究。结果表明：缝洞型油藏试井压力导数曲线上类似“凹子”的特征是由大尺度溶洞向渗流网络的窜流造成的。实例分析表明,新模型解释结果与缝洞型油藏地质特征一致。     

Numerical Simulation of Population Distribution in China

A model for simulating population distribution (MSPD) of China is developed based on the grid generation method and the Control of MapObjects of geographical information system. Elevation, net primary productivity, land use and land cover, city sizes and their spatial distribution, and spatial distribution of transport infrastructures are taken into full account in the MSPD. The result from the MSPD shows that in 2000, 90.8% of the total population of China distributed on the southeastern side of the Heihe-Tengchong line. The ratio of population on the northwestern side to total population of China has been increasing since 1935. The yearly growth rate was 0.8% from 1935 to 1990 and 6.1% from 1990 to 2000. One important advantage of the MSPD is that when scenarios of land cover, spatial distributions of transport infrastructures and cities are available, scenarios of spatial population distribution can be developed on the basis of total population forecast.     

Optimal Forest Management in the Presence of Intraspecific Competition

The Escalator Boxcar Train method is used to solve the distributed optimal control problems of forest management numerically. It takes into account intraspecific competition for scarce resources such as light, space, and nutrients during reproduction, growth, and mortality. It provides an alternative to gradient projection methods and Markov processes. It is implemented with standard software. The application is on the optimal forest management regime in the presence of intraspecific competition.     

二级倒立摆的滑模变结构控制

倒立摆是检验控制算法性能优劣的理想装置。本文以二级倒立摆为控制对象,研究对其实现有效控制的滑模变结构控制策略。在深入研究变结构控制指数趋近律数学本质的基础上,以仿真研究为手段,绘出了其核心参数与倒立摆状态变量性能指标之间的关系曲线。而后根据倒立摆的控制要求,结合曲线走势选定了一组较优的参数。最后使用这组参数进行了仿真实验研究,同时与状态反馈进行了比较,结果表明,滑模变结构控制策略在控制范围和鲁棒性两个方面优于状态反馈控制策略。     

黄土泥岩接触面滑移机理的数值模拟

以晋陕蒙接壤区黄土泥岩接触地带滑坡为工程研究背景,分析研究黄土泥岩接触面的滑坡机理。研究方法主要是室内试验和FLAC2D数值模拟。室内试验确定了黄土的基本物理力学参数,以及黄土泥岩接触面摩擦特性,通过FLAC2D数值计算软件建模并对坡体稳定性进行数值模拟和分析,以接触面水平位移、剪应变及孔压发展等参数变化分析坡角、降雨以及人为活动引起的黄土泥岩接触面滑移机理。     

基于流体分析的发酵釜搅拌器强度计算

大型搅拌釜的搅拌器强度计算难度较大,且高黏流体介质的搅拌功率和搅拌效果难以预测。针对大型发酵釜的 搅拌器设计问题,采用CFD和FEA技术相结合的方法,对发酵釜的搅拌效果和搅拌器强度进行了分析和预测,结果表 明,该分析方法考虑了搅拌器工作过程中流体压力对叶片的作用,对大型搅拌器,尤其是搅拌介质为高黏流体的搅拌器 强度校核和功率预测能够获得较为准确的结果,同时可获得详细的流场信息及各项特性参数。该分析方法可为大型搅 拌器的设计和优化提供参考。     

烟熏炉换热器进口主流道流动性改进

针对某一类型烟熏炉换热器进口主流道出口产生局部负压的问题,借助CFD仿真分析手段找出进口主流道结 构缺陷,提出了岔口几何形状的改变结构。分别对这2种不同结构的进口主流道管在Fluent平台上进行内流场分析,对 比两者之间的差异,表明改进后的进口管流速更加均匀,克服了原进口主流道管存在的问题,使得进入各组U型管的蒸 气相对均匀,换热效率得到提高。     

大断面黄土隧道加宽过渡段变形特性三维数值分析

针对三车道公路隧道加宽段空间跨度大,加宽过渡段设计难度大的难题。以某三车道黄土隧道为依托,采用三维有限元仿真的方法,对加宽过渡段的支护结构和围岩的变形规律进行了研究。研究结果表明：加宽过渡段处初支结构的变形呈现不对称性。距过渡段10 m范围以外加宽段围岩变形趋于对称。加宽段施工对正常段的围岩变形影响较小,对加宽段围岩的影响范围约为10 m。故在三车道公路隧道的加宽段施工过程中,除加强支护外,距离过渡断面的前10 m加宽段施工应提高监控量测频率。     

基于内生增长模型的货币政策效应研究

货币政策是维系经济系统正常运行的必要条件。关于货币政策效应问题一直都未形成统一意见,在此背景下厘清中国货币政策问题有着重要意义。在内生增长理论框架下构建一个包含货币参数的经济增长模型来考察货币供给对经济增长的影响,数值模拟表明在稳定状态下货币供给与经济增长之间呈现倒U型关系。为了验证理论分析结果在实际经济中的适用性,以中国2000—2013年经济数据为例,采用分位数回归模型进行实证检验,实证结果不仅验证了理论分析结果的正确性,也证明了倒U型关系的稳健性。     

Strategies for Appointment Policy Design with Patient Unpunctuality

Appointment policy design is complicated by patients who arrive earlier or later than their scheduled appointment time. This article considers the design of scheduling rules in the presence of patient unpunctuality and how they are impacted by various environmental factors. A simulation optimization framework is used to determine how to improve performance by adjusting the schedule of appointments. Prior studies (that did not include patient unpunctuality) have found that a scheduling policy with relatively consistent appointment interval lengths in the form of a dome or plateau dome rule to perform well in a variety of clinic environments. These rules still perform reasonably well here, but it is shown that a combination of variable‐length intervals and block scheduling are better at mitigating the effects of patient unpunctuality. In addition, performance improves if the use of this policy increases toward the end of the scheduling session. Survey and observational data collected at multiple outpatient clinics are used to add realism to the input parameters and develop practical guidelines for appointment policy decision making.