半导体激光器的高精度温度控制优化设计

温度对半导体激光器(LD)发射器的特性有较大的影响,随着温度的增加,阈值电流呈指数增加,输出功率和斜率分别呈抛物线和指数关系递减,同时特征温度也减少,波长随温度的漂移系数为0.24nm/℃[1].为了使半导体激光器的激光波长和输出功率稳定,必须对其温度进行高精度的控制.利用积分分离式PID控制原理设计了温度控制系统,控制精度达到±0.1℃,与普通PID控制器相比,极大的提高了系统的瞬态特性.     

机电一体化茶青超声波清洗机的设计开发

介绍了一种基于PIC单片机控制的超声波茶青清洗设备，给出了系统及结构的设计、单片机控制电路和功率放大电路的设计，并较详细地阐述了几种换能器的性能比较和控制器的工作原理及结构，使其具有（超声波加气泡发生器）的恒功率清洗功能，满足了茶青表面杂质清洗及去除农残的要求。经试验证明：超声波清洗速度快、效果好、容易实现工业控制，能保持恒定输出功率，且可以方便地调节。     

基于LabVIEW平台的重采样技术的软件实现

介绍了基于LabVIEW虚拟平台的重采样技术的实现，该方法是将三次样条插值应用到重采样技术当中，与纯粹的样本点抽取相结合，实现对高采样率的数据进行任意比例采样率的重采样。经过实验验证，该方法可以很好的满足仿真和动态数字信号分析的需要。     

The Bonding Properties of Solid Steel to Liquid Aluminum

The bonding of solid steel plate to liquid aluminum was studied using rapid solidification. The relationship models of interfacial shear strength and thickness of interfacial layer of bonding plate vs bonding parameters ( such as preheat temperature of steel plate, temperature of aluminum liquid and bonding time ) were respectively established by artificial neural networks perfectly. The bonding parameters for the largest interfacial shear strength were optimized with genetic algorithm successfully. They are 226℃ for preheating temperature of steel plate, 723℃ for temperature of aluminum liquid and 15.8s for bonding time, and the largest interfacial shear strength of bonding plate is 71.6MPa. Under these conditions, the corresponding reasonable thickness of interfacial layer (10.8μm) is gotten using the relationship model established by artificial neural networks.     

Preparation of QTi4.3-4Graghite Composite by Semi-solid Casting Technology

The electromagnetic-mechanical stirring technology was employed for preparing QTi4.3-4 graghite composite slurry,and QTi4.3-4 graghite composite with uniform distribution of graphite particles was prepared uring the semi-solid casting technology successfully.The structure of this QTi4.3-4graphite composite was studied and the condition for uniform distribution of graphite particles was got.The experimental results show that there exists a linear relationship between the solid fraction and the stirring temperature of QTi4.3-4graphite slurry.With the decreasing of stirring temperature,the solid fraction of QTi4.3-4 graghite slurry increases constantly.In casting,with the increasing of solid fraction of QTi4.3-4 graphite slurry.the agglomeration of graphite particles is removed gradually.When the solid fraction is higher than 40%,graphite particles can distribute evenly in QTi4.3-4 graghite composite.     

Microplane Model M5 with Kinematic and Static Constraints for Concrete Fracture and Anelasticity. I: Theory

Presented is a new microplane model for concrete, labeled M5, which improves the representation of tensile cohesive fracture by eliminating spurious excessive lateral strains and stress locking for far postpeak tensile strains. To achieve improvement, a kinematically constrained microplane system simulating hardening nonlinear behavior (nearly identical to previous Model M4 stripped of tensile softening) is coupled in series with a statically constrained microplane system simulating solely the cohesive tensile fracture. This coupling is made possible by developing a new iterative algorithm and by proving the conditions of its convergence. The special aspect of this algorithm (contrasting with the classical return mapping algorithm for hardening plasticity) is that the cohesive softening stiffness matrix (which is not positive definite) is used as the predictor and the hardening stiffness matrix as the corrector. The softening cohesive stiffness for fracturing is related to the fracture energy of concrete and the effective crack spacing. The postpeak softening slopes on the microplanes can be adjusted according to the element size in the sense of the crack band model. Finally, an incremental thermodynamic potential for the coupling of statically and kinematically constrained microplane systems is formulated. The data fitting and experimental calibration for tensile strain softening are relegated to a subsequent paper in this issue, while all the nonlinear triaxial response in compression remains the same as for Model M4.     

RH-KTB大型真空冶金系统智能故障诊断

研究RH-KTB系统的故障种类及特点,进行故障树分析,找出故障间的关系并建立了原始样本采集系统.利用决策树理论对炉外精练大型真空冶金系统的约简集进行快速学习和分类.最后,提出一种基于粗糙集-决策树理论的炉外精炼大型真空冶金系统故障诊断模型.从理论上保证及时对干扰数据进行排除并实现快速诊断.基于该模型开发了一套智能故障诊断系统并应用于大型真空冶金系统,应用效果良好.     

中国钢铁生产量及其能源需求和CO2排放量情景分析

从预测中国的钢铁需求量开始,利用情景分析,预测了钢铁业将来的能源需求和CO2排放量。预测结果表明,中国的钢产量还将继续增长,但应特别注意废钢回用,降低铁钢比,以减少能源需求和CO2排放。     

怎样培养学生的体育意识及能力

要实现终身体育的教育目标 ,学校应加强学生的体育意识及能力培养。可以通过开展选项教学、有意识地培养学生体育需要和加强体育理论基本知识等教学活动 ,来不断增强学生的体育意识和能力。     

Applications of optimal mathematic-physical models in metallurgical manufacture scheduling system at Baosteel

The transfer of mass flow between ironmaking and steelmaking process at Baoshan Iron and Steel Co. Ltd. has been analyzed. The mathematic-physical models of transport scheduling for hot metal manufacturing have been researched combined with the practical problem in the metallurgical manufacture procedure. Taking into account these models, the scheduling software has been designed, programmed and tested on-line. The new automation system of production scheduling has been implemented successfully at Baosteel, which produces a great economic benefit.