PDC钻头切削齿布齿设计的新思路

切削齿布齿设计是PDC钻头设计的关键。为提高PDC钻头的钻进效率,综合考虑PDC钻头切削齿的设计特点和切削先后顺序等因素,并且通过对PDC钻头单切削齿实验结果进行分析,提出了以冠部轮廓法线为基准的切削齿布齿设计方法。     

校院两级管理下的排课软件设计与实现

阐述了排课系统的管理层次、操作权限分配、资源管理、网络排课的具体实现过程。本系统较好地解决了多个校区、多个学院之间的分配资源和排课冲突问题。其特点是资源统一管理、分散使用,利用校园网进行教学管理,不受时间、空间的限制。     

不同布缆方式锚碇沉管管段运动的数值模拟

通过建立波浪作用下锚碇沉管管段运动的时域数值计算模型,对锚碇沉管的运动响应及锚碇缆受力特性进行了研究。应用集中质量法求解锚碇缆力,应用四阶Runge-Kutta法求解管段时域运动方程,计算了在不同沉深、不同周期、不同波高和不同波向条件下沉管管段的运动幅值和锚碇缆力。数值计算的结果表明:锚碇沉管的锚碇缆对沉管管段的运动起到一定的约束作用,在沉放深度较浅、波浪周期较大时,锚碇缆对沉管管段运动幅度的制约更为明显。通过五种布缆方式的计算与分析,探讨了布缆方式对沉管管段运动响应及锚碇缆受力的影响,并给出了较为合理的布缆方案。     

Transport of moderately sorted gravel at low bed shear stresses: The role of fine sediment infiltration

A reliable estimation of sediment transport in gravel‐bed streams is important for various practical engineering and biological studies (e.g., channel stability design, bed degradation/aggradation, restoration of spawning habitat). In the present work, we report original laboratory experiments investigating the transport of gravel particles at low bed shear stresses. The laboratory tests were conducted under unsteady flow conditions inducing low bed shear stresses, with detailed monitoring of the bed topography using a laser scanner. Effects of bed surface arrangements were documented by testing loose and packed bed configurations. Effects of fine sediments were examined by testing beds with sand, artificial fine sand or cohesive silt infiltrated in the gravel matrix. Analysis of the experimental data revealed that the transport of gravel particles depends upon the bed arrangement, the bed material properties (e.g., size and shape, consolidation index, permeability) and the concentration of fine sediments within the surface layer of moving grains. This concentration is directly related to the distribution of fine particles within the gravel matrix (i.e., bottom‐up infiltration or bridging) and their transport mode (i.e., bedload or suspended load). Compared to loose beds, the mobility of gravel is reduced for packed beds and for beds clogged from the bottom up with cohesive fine sediments; in both cases, the bed shear stress for gravel entrainment increases by about 12%. On the other hand, the mobility of gravel increases significantly (bed shear stress for particle motion decreasing up to 40%) for beds clogged at the surface by non‐cohesive sand particles. Copyright © 2017 John Wiley & Sons, Ltd.     

山东黄河水利工程移民安置规划浅论

移民安置关系社会稳定和经济可持续发展。要采取措施,尽快恢复生产,使搬迁居民达到或超过原有生活水平。移民安置规划主要内容包括实物指标调查、农村移民生产措施规划、居民点规划及专项处理规划等。实物指标调查是移民安置规划设计的第一步基础工作。实物数量、现状的标准等是确定移民安置规模和专业项目复建规划的重要依据。移民安置规划是移民规划设计的核心。农村移民生产安置方案的制定和措施的落实是移民安置规划设计的重点,移民生活安置环境容量的分析与移民安置目标的确定则是移民安置规划的关键。     

C10TAB,C14TAB,C18TAB柱撑蒙脱石层间域有机柱排布研究

用十烷基三甲基溴化铵（C10TAB）、十四烷基三甲基溴化铵（C14TAB）和十八烷基三甲基溴化铵（C18TAB）制备有机柱撑蒙脱石,并对产物进行X射线衍射表征。研究结果表明：柱化剂的浓度和烷基季铵离子的性质能影响烷基季铵离子在蒙脱石层间的排布模式。在柱化剂浓度较低时易形成平卧排列,柱化剂达到一定浓度时石蜡型结构方能形成,且直链烷基越长,烷基季铵离子在蒙脱石层问越易形成石蜡型倾斜排列。在平卧结构向石蜡型结构转化过程中可出现多种排列共存。     

浙江仙居县漂流旅游的气候影响因素探讨

采用仙居县漂流旅游项目营业开始迄今的客流量和同期的降水、相对湿度、风速和气温等气象资料对仙居县永安溪漂流的气候影响因素进行了研究。分析了当地的人体舒适度指标,统计了月平均舒适天数,同时探讨了降水和高温的影响,得出适宜的气候条件,计算了各指标的距乎百分率,并与客流变化作对比分析。结果表明：5月和10月气候适宜且旅游流量高;4月、7月和9月也为适宜时段,但客流量少,旅游资源有待进一步挖掘。     

Optimization of slope angle and its seismic stability: A case study for the proposed open pit coalmine in Phulbari, NW Bangladesh

The present study reflects upon the results of substantial program of two-dimensional Finite Element Method （FEM） numerical analyses of the open pit that links to slope angle optimization associated with the safety factor of the pit slope of a coal mine in Bangladesh. In the present analyses, two types of models have been presented. The first model estimates safety factor without seismic effect on the overall pit slope of the model; the second model incorporates safety factor with seismic stability of the model. The calculated optimum slope angle of the first model is 31% with a rational safety factor of 1.51, prior to the seismic effect. However, the value is reduced to 0.93, 0.82, and 0.72, after we applies the seismic effect in the second model with M6, M6.5, and M7, respectively. Finally, our modeling results emphasize that for the case of the proposed Phulbari coalmine, there is extremely high prospect for causing massive slope failure along the optimum pit slope angle with 31% if the mine area felt seismic shaking, like the Sikkim （in northern India） earthquake with M6.9 on September 18, 2011.     

不同节点布置下二维涡激振动的无单元法参数化分析

尝试建立1种基于无单元法的涡激振动数值模拟算法,并给出适用于涡激振动分析的前处理自动布点方法.基于无单元法理论,使用动最小二乘法构造形函数,利用无单元伽辽金法,采用速度和压力分离模式,及手工布点和自动布点2种方法所得出的节点布置形式,对流场控制方程进行空间离散,模拟二维涡激振动的流场形态,并对VIV相关参数进行分析,计算不同节点布置情况下的升力系数(Cl)、曳力系数(Cd)及斯特罗哈数(St),并与物理模型实验结果进行对比.计算结果表明,无单元伽辽金法应用于立管VIV分析是可行的,且文中采用2种布点方法均能较好的模拟流场中泻涡脱落的形态,计算结果与传统方法和物理模型实验结果吻合良好.证明文中2种布点方法都能用于固定圆柱的二维VIV分析,但自动布点法能够更好地适用于复杂问题的计算及圆柱体在流场中的VIV动力响应分析.     

深埋电极的地电阻率观测研究

首先研究了四极观测系统装置系数与电极埋深的关系;然后给出了点电流源在3层地壳模型的地表和第二层时,电源所在层的电位的解析表达式;最后将天津宝坻地区的电性结构简化成一个3层模型,计算给出了当地表层和基岩中的电阻率出现变化时,在地表和基岩上层开展四极地电阻率观测结果与供电极距和深度的关系.