永久船闸钢筋接头机械连接生产性试验

我国引进国外先进经验研制成功的钢筋接头机械接头技术，现已在工业与民用建筑领域广泛应用。机械连接对于确保钢筋接头质量，改善施工环境、提高工作效率，保证工程进度具有明显的优势。三峡水利枢纽永久船闸输水系统于１９９８年１１月开始进行钢筋接头机械连接生产性试验，取得了初步经验。     

三峡永久船闸深槽开挖施工技术

在复杂条件下 ,为满足三峡永久船闸闸室槽挖及边坡稳定的要求 ,以达到优质、高效、安全施工的目的 ,采用了一系列诸如爆破方式、设计参数、微差爆破及成型爆破等综合控制技术。通过深槽开挖施工实践 ,总结了对高边坡、高应力释放区的成型爆破措施以及槽、井、洞开挖爆破相互影响的关系、爆破与锚固之间相互影响的关系     

模数法设计金属型铸造铝活塞保温冒口

根据保温冒口的散热特征,引用有效散热系数修正凝固模数,进一步修正金属型铸造的凝固比得出金属型保温胃口方程式.并设计了东风EQ140汽车活塞的保温冒口.浇注实验结果显示:铸造工艺出品率提高到84.9%,显著提高了冒口有效补缩效率.     

磨削加工对圆柱钕铁硼永磁合金退磁曲线隆起度的影响

发现圆柱钕铁硼永磁合金经过磨削加工后，其内禀退磁曲线隆起度降低，从而也降低了磁能积。通过实验证明，隆起度降低是磨削加工应力所致，适宜的磨削工艺和热处理则可减少和消除其影响。     

Achievement of high performance of sintered R-Fe-B magnets based on misch metal doped with PrNd nanoparticles

The magnetic properties and microstructure of sintered R-Fe-B(R, rare earth) magnets with nominal composition of((PrNd)_1-xMM_x)₃₀Fe_balB_1(x = 0, 0.1.0.2,0.3, 0.4, 0.5 and 0.7; MM, misch metal) prepared using dual-alloy method were investigated. For x = 0.3, the maximum energy product((BH)_max) of the sintered magnet is higher than 318.4 kJ·m^-3,but intrinsic coercivity(H_cj) is lower than 351.8 kA·m^-1. The La and Ce contents are obviously different in some matrix-phase grains, which proves that the multi-hard magnetic phases(La, Ce-rich and La, Ce-lean) exist in the magnets. The coercivity is improved by the method of doping PrNd nanoparticles without sacrificing other magnetic properties. An enhancement in coercivity from 517.2 to 872.9 kA·m^-1 is achieved by doping 5 wt% PrNd nanoparticles. Meanwhile, it could exhibit better magnetic properties(remanence B_r = 1.332 T.intrinsic coercivity H_cj= 872.9 kA·m^-1 maximum energy product(BH)_max=318.6 kJ·m^-3) and make the distribution of the intergranular phase become more homogeneous.     

数控强力旋压机的直线同步进给驱动控制

针对3D65CNC强力旋压机同步驱动过程中的两直线电机位置不同步的问题,采用变论域模糊PID控制方法对两永磁同步直线电机的位置误差进行补偿,设计了变论域模糊PID同步控制器。但单轴具有良好的伺服系统是双轴保持同步状态的重要前提,针对直线电机具有明显的非线性、不易对其进行精确的建模,采用无模型自适应控制和伪微分反馈(PDF)控制的方法对单轴直线电机进行控制。最后通过Simulink仿真证明该方案提高了同步控制的精度。     

反推法在永磁同步电动机速度控制中的应用

反推设计方法是一种新颖的设计方法。针对永磁同步电动机的非线性与强耦合特性,选取适当的Lyapunov函数,引入虚拟控制设计反推控制器,保持系统的渐近稳定,实现对电机转速的实时跟踪;在此基础上设计了以数字信号处理器为核心的数字化控制系统。仿真结果证实了该方法的有效性     

Seismic displacements of landfills and deformation of geosynthetics due to base sliding

Seismic design of waste landfills has been a subject of intense research over the past two decades, primarily due to the severe environmental impact of a potential failure. The majority of the related studies have been focused on the stability assessment of landfills utilizing permanent deformation methods. However, previous investigations have not fully addressed the impact of the composite liner system on the seismic performance of the geostructure, mainly expressed as potential sliding development, which is greatly affected by the geometry and the resulting initial static stress state of the landfill. Therefore, the aforementioned issues are investigated via a detailed parametric study, where the dynamic behaviour of the composite liner system is examined both analytically and numerically. The conducted coupled analyses indicated that the most significant parameters of the complex dynamic response of waste landfills can be reduced in two ratios that comprise functions of the main characteristics of the geostructure and of the excitation. Moreover, two distinct failure patterns have been identified with respect to the characteristics of the distribution of the permanent displacements along the interface and the axial deformation along the geosynthetic. The occurrence conditions of these failure patterns can be determined in terms of the two abovementioned ratios as verified by the analytical results of the critical acceleration of a simple SDOF system.     

纯棉织物低甲醛耐久阻燃整理工艺研究

采用多元酸作为交联剂对棉织物进行低甲醛耐久阻燃整理，研究低甲醛耐久阻燃整理工艺条件，探讨影响阻燃效果的各种因素。与N—羟甲基酰胺类交联剂工艺进行比较，本工艺不仅显著降低织物中游离甲醛含量，还提高了阻燃效果，且阻燃剂、交联剂的用量大大减少，阻燃成本降低。