Packing,compressibility, and crushability of rockfill materials with polydisperse particle size distributions and implications for dam engineering

In rockfill dam engineering, particle breakage of rockfill materials is one of the major factors resulting in dam settlement. In this study, one-dimensional compression tests on a series of coarse granular materials with artificially-graded particle size distributions (PSDs) were carried out. The tests focused on understanding the role of initial PSDs in the dense packing density, compressibility and crushability of coarse granular materials. The effects of fractal dimension (D) and size polydispersity (θ) of PSDs were quantitatively analyzed. Two different loading stages were identified from the logarithms of the stress–strain relationships, with the turning point marked as the yield stress. A similar effect of initial PSDs was observed on the packing density and low-pressure modulus of coarse granular materials. The packing density and low-pressure modulus increased monotonically with θ, and their peak values were attained at a D value of approximately 2.2. However, there was no unique correspondence between the dense packing density and low-pressure modulus. The particle breakage was influenced differently by the initial PSDs, and it decreased with the values of D and θ. The emergence of the unique ultimate state was also identified from both the compression curves and PSDs of the samples after the tests. The potential implications of the test results in the design of both low and high rockfill dams were also demonstrated.     

高效波纹填料塔在甲醇精馏分离中的应用及前景

本文通过高效网孔波纹填料塔在12000t/a甲醇生产装置中成功应用的实例,阐明将高效网孔波纹填料塔应用于甲醇精馏过程能取得良好的效果。与浮阀塔等塔设备相比具有节能降耗、降低塔高、保护环境等优点。     

中,高压浇注成型坯体的特性

卫生陶瓷中，高压浇注成型工艺是当今世界上的最新工艺，而该工艺在我国目前处于研究阶段未被广泛应用。本文在实验的基础上，对压力浇注成型坯体的特性（干燥粒子的堆积密度、坯体的残留水份、干燥收缩与坯体的结构等）进行了研究，得出了一些有价值的结论。     

Numerically packing spheres in cylinders

A novel approach has been developed to numerically pack spheres in cylinders. The packing algorithm uses a simple sequential technique that is based on a dimensionless packing parameter. The dimensionless packing parameter includes both axial and radial variables in order to determine a sphere's sequential placement within a cylindrical packing structure. The numerical simulation has been applied to the loose packing of identical spheres in cylindrical containers with D/d ≥ 2.0. The predicted results for the mean porosity and the radial porosity distributions are validated against the available experimental data for spheres in cylindrical containers. The simulated results are highly accurate and the simple packing algorithm requires minimal computational prerequisites.     

基于格局变换策略的不等圆Packing问题求解算法*

采用基于格局变换策略的算法ACP-Solver求解不等圆Packing问题。ACP-Solver由连续优化方法、格局变换算子和接收准则组成。连续优化方法可从任一初始格局收敛至对应的局部最优格局。格局变换算子将当前格局变换为新格局。接收准则决定是否接收变换所得格局。基于24个国际公开算例的计算实验表明,ACP-Solver能在可接受的计算时间内改进或持平绝大多数算例的当前最优记录。实验结果表明了ACP-Solver的高效性能。     

一个基于启发式经验的立体布局进化策略

目前求解布局问题只能求得近似解,三维布局则更加复杂。本文提出一种基于启发式经验、采用遗传算法求解布局问题的新方法,此方法对任意维布局问题在求解策略上是一致的。实验表明,结合领域知识和遗传算法对解决布局问题具有广泛的前景。     

塑料注射成型保压过程数学描述

在对塑料注射成型中保压过程进行深入分析的基础上,提出了合理的假设并进行了必要的简化,利用连续介质力学的基本方程导出了可压缩、非牛顿粘性流体在模具型腔中非等温流动的控制方程,选用了恰当的材料性质模型,建立了可对保压过程进行数值模拟的数学模型。     

改进型孔板波纹填料的性能研究

介绍了北京化工大学传质分离研究室开发的新型规整填料──金属（碳钢）桥孔板波纹填料。并对其流体力学性能和传质性能进行了冷模实验研究,提出了相应的关联式和图表。与孔板波纹填料相比,它是一种适应更广泛、性能优越的高效填料。     

饮料包装材料数据库

从研究饮料包装材料出发,建立饮料包装材料数据库。     

磁粉离合器磁粉特性及其相关参数的关系

本文研究了：不同形式磁导仪和磁粉不同填充密度对所测磁粉静态磁感应强度Ｂ值的影响;动态磁感应强度Ｂδ与Ｂ的相对关系。通过数据分析,找出了其间所存在的规律,其研究结果对统一磁粉静态磁性能测试方法、简化磁粉离合器主要参数的设计计算、分析磁粉离合器在使用中出现的问题,具有重要的参考价值。