超声波检测混凝土结构抗冻性的方法研究

依据固体结构动弹模与表面波速度的关系，采用超声波检测混凝土冻融试件的动弹模，并与共振法测出的动弹模进行对比，总结出其内在相关规律，建立起预报混凝土动弹模的回归主程，由测得的波速计算出相应的动弹模，再利用动弹模之比评估出混凝土结构的抗冻性。初步试验和研究表明，此方法研究思路切实可行，符合混凝土冻融特性的基本变化规律，能够实现从度件测试向结构检测的发展，可供混凝土耐久性检测工程参考。     

排桩式波浪能发电装置附近流场特性研究

基于雷诺时均Navier-Stokes方程和k?ω湍流模型,研究单排桩式振荡水柱式波浪能发电装置在规则波作用下的桩基附近流场特性. 通过物理模型实验验证所建数值波浪水槽的准确性. 模拟规则波作用下装置附近的流场特性,分析装置附近的涡特征以及其对装置附近泥沙冲刷情况的潜在影响. 结果表明,测试工况下,在桩式振荡水柱装置桩柱体的桩基附近观察到马蹄涡和尾涡现象,马蹄涡强度随着Keulegan–Carpenter（KC）数的增大而减小,尾涡强度随着KC数的增大而增大. 马蹄涡因强度过小,在模拟的KC数范围内不是装置桩基泥沙冲刷的主要因素,高强度的尾涡很可能成为装置桩基附近泥沙起动、输运和冲刷的重要影响因素.     

AN EXPERIMENTAL-NUMERICAL METHOD FOR MEASURING CRACK PROPAGATING VELOCITIES UNDER STRESS WAVE LOADING

An experimental-numerical method for measuring dynamic crack propagating velocities under stress wave loading is established in this paper. The experiments of the three-point bend specimen are done on the improved Hopkinson bar. Deflection of loading point, dynamic load and instantaneous crack length are measured, then crack propagating velocities are calculated. Experiments on 40Cr steel show that the results given by this method have a good agreement with that obtained by the resistance fracture gage method. Therefore this method is feasible for measuring crack propagating velocities under high loading rate and will have wide application.     

汽车喷烤漆自动控制系统

本文通过研究目前汽车烤漆房的实际运行情况，提出了一种汽车烤漆房喷漆自动控制系统，阐述了系统喷漆装置的构成、配合与运行原理，并构成了实际试验系统。     

WAVE FIELD EXTRAPOLATION IN VISCOELASTIC MEDIUM AND VARIABLE FOCUS METHOD TO SEPARATE SEISMIC COMPOUND WAVE

ＷＡＶＥＦＩＥＬＤＥＸＴＲＡＰＯＬＡＴＩＯＮＩＮＶＩＳＣＯＥＬＡＳＴＩＣＭＥＤＩＵＭＡＮＤＶＡＲＩＡＢＬＥＦＯＣＵＳＭＥＴＨＯＤＴＯＳＥＰＡＲＡＴＥＳＥＩＳＭＩＣＣＯＭＰＯＵＮＤＷＡＶＥ￥ＳｏｎｇＳｈｏｕｇｅｎ；ＹｕａｎＸｉｕｇｕｉ；ＨｅＪｉｓｈａｎ...     

露天矿山深-浅耦合台阶爆破方法研究及应用

爆破大块率高一直是困扰国内外众多露天矿山的技术难题,银山矿露天采矿场由于采区地质条件复杂,爆破大块率高的现象尤为明显。为此,针对露天采矿场岩性复杂易产生大块的区域,基于岩石的物理力学性质,计算出千枚岩和斑岩爆破区域需增设的短孔孔位。为减少爆破大块的产生率,提出了中深孔爆破方法—深-浅耦合台阶爆破方法。在银山矿露天采矿场实施深-浅耦合台阶爆破方法后,爆破大块率得到有效控制并取得了显著的社会及经济效益。     

Ability of the direct wave of radar ground-coupled antenna for NDT of concrete structures

The research work presented in this paper aims at evaluating the potential of the direct wave of radar ground-coupled antennas for the on site physical characterization of concrete. According to studies highlighting the ability of radar reflected waves to characterize concrete, the potential of the direct wave is studied by systematic comparison of direct and reflected wave attenuations. Among the various features of electromagnetic waves propagating through concrete, attenuation is the most sensitive to moisture and chloride contents. In order to study the sensitivity of the direct wave to the physical condition of the concrete, laboratory experiments were conducted on concrete slabs with various porosities, water contents and chloride contamination levels.The results of this study show very satisfactory correlations between attenuations of direct and reflected waves, indicating that both waves provide similar information regarding the physical state of concrete. This correlation was confirmed on two bridges by comparison of direct wave attenuation maps with reflection attenuation maps. Therefore, radar interpretation method based on the direct wave attenuation should be able to detect, in a very fast way, physical contrasts in concrete structures and, consequently, identify probable pathological areas.     

波形控制逆变CO2焊接电源关键控制信号的获取

通过分析波形控制CO2焊接过程，介绍了焊接电源空载、燃弧、短路等工作状态的判别，电流、电压、du/dt、di/dt等关键信号的获取方法，为研制波形控制CO2逆变焊机奠定了基础。     

Adaptive model predictive inventory controller for multiproduct warehouse system

An inventory control system has been developed for a distribution system consisting of a single multiproduct warehouse serving a set of customers and purchasing products from multiple vendors. Purchase orders requesting multiple products are delivered to the warehouse in a process referred to as joint replenishment. The receipt of customer orders by the warehouse proceeds in order intervals and in order quantities that are subject to random fluctuations. The objective of warehouse operation is to minimize the total cost while maintaining inventory levels within the warehouse capacity by adjusting the purchase order intervals and quantities. An adaptive model predictive control algorithm is developed using a periodic square wave model to represent the material flows. The adaptive concept incorporates a stabilized minimum variance control-type input calculation coupled with input/output stream parameter predictions. The boundedness of the control output under the suggested algorithm is mathematically proven under the assumption that disturbances in the orders are bounded. The effectiveness of the scheme was demonstrated using simulations.     

二维坡面雨洪水动力模型研究

由降雨产生的坡面洪水运动过程复杂,其可靠模拟仍有待深入。该文建立了基于浅水方程的二维坡面雨洪动力过程模拟的动力波模型,选用单坡、三阶坡面和复杂起伏多变坡面的雨洪运动为数值算例,进行了数值检验并与忽略惯性项的扩散波模型进行了对比分析。结果表明:动力波模型可以较好地模拟洪水过程,在峰现时间,洪峰水位的捕捉和退水过程等方面都表现出优良的特性;而且动力波模型在复杂坡面雨洪过程计算的适应性方面表现更佳。而扩散波模型在计算精度和稳定性方面都相对要差。虽然扩散波模型在单坡面算例中的计算精度也较高,但因受忽略惯性项的影响,退水过程有明显偏离。