Separation of hematite from banded hematite jasper (BHJ) by magnetic coating

The separation of iron oxide from banded hematite jasper(BHJ) assaying 47.8% Fe, 25.6% Si O2 and 2.30%Al2O3 using selective magnetic coating was studied. Characterization studies of the low grade ore indicate that besides hematite and goethite,jasper, a microcrystalline form of quartzite, is the major impurity associated with this ore. Beneficiation by conventional magnetic separation technique could yield a magnetic concentrate containing 60.8% Fe with 51% Fe recovery. In order to enhance the recovery of the iron oxide minerals, fine magnetite, colloidal magnetite and oleate colloidal magnetite were used as the coating material. When subjected to magnetic separation, the coated ore produces an iron concentrate containing 60.2% Fe with an enhanced recovery of56%. The AFM studies indicate that the coagulation of hematite particles with the oleate colloidal magnetite facilitates the higher recovery of iron particles from the low grade BHJ iron ore under appropriate conditions.     

A multi-start central force optimization for global optimization

Central force optimization (CFO) is an efficient and powerful population-based intelligence algorithm for optimization problems. CFO is deterministic in nature, unlike the most widely used metaheuristics. CFO, however, is not completely free from the problems of premature convergence. One way to overcome local optimality is to utilize the multi-start strategy. By combining the respective advantages of CFO and the multi-start strategy, a multi-start central force optimization (MCFO) algorithm is proposed in this paper. The performance of the MCFO approach is evaluated on a comprehensive set of benchmark functions. The experimental results demonstrate that MCFO not only saves the computational cost, but also performs better than some state-of-the-art CFO algorithms. MCFO is also compared with representative evolutionary algorithms. The results show that MCFO is highly competitive, achieving promising performance.     

WAVE INTERACTION WITH PERFORATED CAISSON BREAKWATERS

The reflection coefficient of perforated caissons and the total horizontal forces acting on them were experimentally and numerically analyzed and discussed when wave propagates normally. To consider the viscosity effect of fluid and nonlinear action of waves on structures, the VOF (Volume Of Fluid) method combined with the k-ε turbulence model was used to simulate the interaction between waves and structures. Governing equations were solved with the finite difference method. Through 2D experimental study in the wave flume, the empirical relationship between the reflection coefficient of perforated caissons and the main affecting factors were obtained from the experimental data using the least square method. Also the correlation between the ratio of the total horizontal force acting on perforated caisson and the force acting on solid caisson and the main affecting factors were regressed from the experimental data.     

基于TS101的PCI接口高速数据采集系统的设计

给出了基于TS101和PCI的双通道数据采集处理系统的设计方案。首先介绍了ADI公司新型数字信号处理(DSP)微处理器TS101和FLYBY数据传输模式,阐述了系统结构和工作原理,最后对如何利用TS101的FLYBY接口提高数据采集、存取效率和数据系统的逻辑控制进行了详细的论述。     

串行及并行A/D转换器在高速数据采集中的采样差别性分析

串行和并行接口模式是A/D转换器诸多分类中的一种,但却是应用中器件选择的一个重要指标.在同样的转换分辨率及转换速度的前提下,不同的接口方式不但影响了电路结构,更重要的是将在高速数据采集的过程中对采样周期产生较大影响.本文通过12位串行ADC ADS7822和并行ADC ADS774与AT89C51的接口电路,给出二者采样时间的差异性.     

MAX3100在80C196串口扩展中的应用

介绍采用新型的UART器件MAX3100为Intel单片机80C196扩展串口，给出了硬件设计和软件编程，并对关键技术进行了说明。     

岩石物理横波速度曲线计算技术

横波速度是地震勘探中的重要参数。针对实际生产中缺乏横波速度测井曲线资料，利用经验公式计算精确度不高的问题，通过对横波速度计算理论模型的研究分析，选择Blot-Gassman模型法，利用岩石矿物成分、流体成分、孔隙度及密度等测井曲线进行横波速度测井曲线的计算，并对横波速度计算技术和流程进行研究。在实际工区进行了横波速度曲线计算，计算结果与实测横波吻合程度较高，误差小于10％，该技术在储层和流体识别预测的应用中取得了较好效果。     

600 A IGBT开关电路及其散热系统设计

采用IGBT开关电路，对大功率电阻带进行直流脉宽调制控制，实现了内燃机车大功率直流发电机负载实验中的负载大小的连续调节。为了避免在实验过程中IGBT器件的温度过高，采用独特的双管IGBT结构和双向强迫风冷的散热系统。实验表明该电路运行稳定、可靠。