滩坑水电站面板堆石坝筑坝新工艺

滩坑水电站筑坝施工防渗墙施工不留龙口,实施先闭气后截流的导截流施工方案,使工期提前1个多月。采用抛石挤淤工艺,实现了基坑深覆盖层坝基开挖快速施工。汛期适当提高坝体填筑高程,在坝面高差处设置超径石保护,坝面经多次过流冲刷少,同时大大减少了溢洪道备料开挖。坝内预埋水管,高压水泵直供坝面喷射洒水,洒水均匀且经济安全。利用液压挖掘机作导向地锚,推土机牵引进行斜坡碾压,不需专用设备,坡面碾压质量好,实现了高面板坝优质快速施工。     

Study on Numerical Simulation of Mold Filling and Solidification Processes under Pressure Conditions

The mold filling and solidification simulation for the high pressure die casting (HPDC) and low pressure die casting (LPDC) processes were studied.A mathematical model considering the turbulent flow and heat transfer phenomenon during the HPDC process has been established and paralled computation technique was used for the mold filling simulation of the process.The laminar flow characteristics of the LPDC process were studied and a simplified model for the mold filling process of wheel castings has been developed.For the solidification simulation under pressure conditions,the cyclic characteristics and the complicated boundary conditions were considered and techniques to improve the computational efficiency are discussed.A new criterion for predicting shrinkage porosity of Al alloy under low pressure condition has been developed in the solidification simulation process.     

视觉技术在YP19装封箱机中的设计与应用

介绍视觉技术在YP19装封箱机的装箱过程中的应用,简述视觉技术系统的基本组成、工作原理及软件设计。     

最长公共子序列算法在填空题评分程序中的应用

讨论最长公共子序列算法在填空题评分中的应用,并具体设计一种基于网络环境下,考试系统中的填空题题型的通用答案识别逻辑,在独立学院网络考试系统中操作可行。     

水工建筑物下伏采空区稳定性评价及治理措施研究 ——以彬长矿区输配水工程为例

位于煤矿采空区上的水工建筑物,存在采空引起的沉陷问题,沉陷使采空区上覆岩层的围岩失稳,使地表变形呈现裂缝、塌陷台阶等不同型式的地质灾害,导致建筑物受损,并影响其安全稳定性,使工程建筑物不能发挥其功能。为此需对采空区进行勘察研究,研究其垮落型式和垮落体体积,在此基础上采用概率积分法,对建筑物下伏采空区引发的地表变形进行计算预测,分析评价剩余变形量的稳定性,确定建筑物下伏采空区治理标准,研究采空区的治理范围、防治措施、施工方法,提出质量控制要求。通过垂直钻孔、全胶结法灌浆充填的方法对深层煤炭采空区进行治理,用钻孔检测等多种方法对治理后的采空区进行检测,其倾斜值、曲率值、水平变形值、水平移动值和下沉量均小于采空区场地变形允许值。说明对剩余空洞体灌注混凝土的治理方法达到了预期效果,可以为同类采空区治理工程提供借鉴经验。     

The social parameter of "learned" helplessness: Its recognition and implications.

Reexamines experiments on learned helplessness that have been interpreted previously as involving a solitary person experiencing uncontrollable and inescapable events. It is suggested that the belief that the outcomes are uncontrollable precludes the possibility that control of the outcomes can be transferred to the experimental Ss. An alternative interpretation is that the outcomes in learned helplessness experiments, rather than being uncontrollable, are controlled by the experimenter. Helplessness could be reduced by transferring this control to Ss, giving them control over their contingencies. This analysis has implications regarding both the accuracy of depressed people's perceptions and the desirability of making depressed people perceive an internal locus of control. It is further suggested that depressed people should have more control over their contingencies. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

数值模拟铸件充型过程中的液/固两相流动

铸造过程中熔融金属内的固体渣粒的运动轨迹是非常重要的。文中给出了粒子传输轨迹的数学模型,该数学模型采用显示法来确定粒子的位置。模拟研究结果与用其它数学模型的模拟结果比较,吻合良好。该模型可用于固体粒子位置的确定,并应用到SUTCAST软件中。     

Mensuration and simulation of mold filling process in semi-solid die-cast of aluminum alloy

To understand the flow trace of semi-solid slurry in mold cavity, some thermocouples were inserted in mold cavity, and the reaction timing of thermocouples showed the arrival of fluid. The filling time and rate were estimated by comparison between the experiment and calculation. The introduction of computer simulation technique based on ADSTEFAN was to predict injectionforming process and to prevent defects during trial manufacture of various parts. By comparing the formed appearance of parts in experiment and in simulation, and observing the relationship between internal defects inspected by X-ray or microscope and the flow field obtained in simulation, it was indicated that both have quite good agreement in simulation and experiment. Right predictions for cast defects resulted from mold filling can be carried out and proper direction was also proposed. The realization of numerical visualization for filling process during semi-solid die-cast process will play an important role in optimizing technology plan.     

筑坝细粒填料的含水率对连续压实指标的影响

为研究筑坝细粒填料的含水率对土石坝连续压实控制技术的影响,根据相似理论开展了室内模拟试验,研究了振动测值在不同填料含水率下的变化规律。通过线性回归分析,研究了填料含水率变化对相关性校准的影响及与不同类别连续压实控制指标的适用性。结果表明：（1）相同振动压实条件下VCV（vibration compaction value）指标受填料含水率影响较小,但Ks指标正好相反;（2）在现场碾压过程中采用CMV（compaction meter value）和CCV（compaction control value）指标时要保证填料含水率不超过最优含水率;（3）填料含水率在最优含水率变化幅度不大于2%时,CCV和VCV（vibratory control value）指标与压实度K具有强相关性;（4）在土石坝碾压中确定细颗粒填料的连续压实指标时,要重视填料含水率对指标的影响规律。     

A level set based immersed boundary method for simulation of non-isothermal viscoelastic melt filling process

In this work, the polymer melt filling process is simulated by using a coupled finite volume and level-set based immersed boundary (LS-IB) method. Firstly, based on a shape level set (LS) function to represent the mold boundary, a LS-IB method is developed to model the complex mold walls. Then the non-isothermal melt filling process is simulated based on non-Newtonian viscoelastic equations with differ-ent Reynolds numbers in a circular cavity with a solid core, and the effects of Reynolds number on the flow patterns of polymer melt are presented and compared with each other. And then for a true polymer melt with a small Reynolds number that varies with melt viscosity, the moving interface, the temperature distributions and the molecular deformation are shown and analyzed in detail. At last, as a commonly used application case, a socket cavity with seven inserts is investigated. The corresponding physical quantities, such as the melt velocity, molecular deformation, normal stresses, first normal stress differ-ence, temperature distributions and frozen layer are analyzed and discussed. The results could provide some predictions and guidance for the polymer processing industry.