柴油馏分深度加氢脱硫过程中有色体形成机理的研究

为了生产含低硫、色度好的柴油产品，采用计算机分子模拟技术研究了柴油馏分深度加氢脱硫(HDS)过程中多环芳烃有色体的形成机理。研究结果显示，柴油馏分中难脱除硫化物4-MDBT、4，6-DMDBT的HDS中间产物生成多环芳烃的反应历程中每步反应的活化能较低，其中的缩合环化反应为吸热反应。模拟产物符合实验事实，表明模拟计算的多环芳烃有色体形成路径是可能的、合理的。     

Modeling of laser cladding with powder injection

Laser cladding is one of the material additive manufacturing processes used to produce a metallurgically bonded deposition layer. To obtain a high-quality resulting part, a deep understanding of the underlying mechanisms is required. In this article, a mathematical model is developed to simulate the coaxial laser-cladding process with powder injection, which includes laser- substrate, laser-powder, and powder-substrate interactions. The model considers most of the associated phenomena, such as melting, solidification, evaporation, evolution of the free surface, and powder injection. The fluid flow in the melt pool, which is mainly driven by Marangoni shear stress as well as particle impinging, together with the energy balances at the liquid-vapor and the solid-liquid interfaces, are investigated. Powder heating and laser power attenuation due to the powder cloud are incorporated into the model in the calculation of the temperature distribution. The influences of the powder injection on the melt pool shape, penetration, and flow pattern are predicted through the comparison for the cases with powder injection and without powder injection. Dynamic behavior of the melt pool and the formation of the clad are simulated. The effects of the process parameters on the melt pool dimension and peak temperature are further investigated based on the validated model.     

Receding horizon finite memory controls for output feedback controls of state-space systems

In this paper, a new type of control, called a receding horizon finite memory control (RHFMC) or a model predictive finite memory control, is proposed as an optimal output feedback control for stochastic state-space systems. Constraints such as linearity, finite memory structure, and unbiasedness from the optimal state feedback control are required in advance, and in addition, the performance criterion of quadratic cost is required. Constraints for the input and the state are not assumed in this paper. The RHFMC is obtained directly by minimizing the performance criterion for stochastic state-space systems with the previous constraints. It is shown that the RHFMC can be separated into a receding horizon control and a finite-impulse response filter. The stability of the RHFMC is investigated. The validity of the proposed RHFMC is illustrated by a numerical example.     

Parallel Processing of First Order Linear Recurrence on SMP Machines

In this paper, we propose a new algorithm that analyzes the data dependency pattern in the first-order linear recurrence (FOLR) and transforms it into algebraically equivalent expanded form so that it can be processed in parallel using the threads on symmetric multiprocessor (SMP) machines. The transformation aims to eliminate the data dependencies in the naive nested form of the FOLR. However, as this transformation may result in extra multiplication operations, our algorithm examines the immanent overhead of the expanded form of the FOLR and generates a new hybrid form of the FOLR. The hybrid form combines nested and appropriately expanded form in order to make it suitable for parallel processing. The parallel algorithm based on the hybrid form of the FOLR is analytically examined and tested through implementation on SMP machines. The implementation details, such as the workload balancing between processors and the optimization of cache performance, are also discussed. The experimental results show that the parallel algorithm based on the hybrid form of the FOLR considerably improves the performance on SMP machines that have three of more processors.     

医学影像存储与传输系统PACS的研究与探讨

为促进我国PACS的迅速发展,构建医学信息网络资源,从研究PACS的关键技术出发,结合实际探讨实施PACS方案。     

基于单片机的接口扩充

介绍利用AT89C51单片机,作为可编程接口芯片的使用方法。系统扩展了二个定时/计数器、二个外部中断、一个8×8阵列键盘和8位LED显示器。从而实现了扩充系统成本的下降,同时也优化了系统的硬件结构和软件的设计。     

浅谈中小型变频调速隔爆电动机的设计与选型

从变频调速电动机的基本原理、特点及其在不同负载下的特性等方面，对中小型变频调速隔爆电动机的设计与选型进行了分析，并对选型中应注意的问题进行了介绍。     

网络环境下的蓄电池智能监测系统设计

介绍了一种新型智能蓄电池监测系统的设计方案，并进一步研究了网络环境下蓄电池监控数据的加工处理，以实现蓄电池监测软计算模型的动态进化。     

汽轮发电机组轴向振动的分析和处理

从轴向振动的机理入手,结合现场试验研究,对汽轮发电机组轴向振动进行了详细的分析,提出了处理解决的方法,实践证明是行之有效的.     

滑动回归最小二乘算法在某电动振动台模型辨识中的应用

在分析电动振动台数学模型的基础上,利用先进的滑动回归最小二乘辨识算法,有效地开展了电动振动台这一复杂电力学系统阶数和时延的确认、参数估计,并建立了系统的ARMA模型.给出了某型电动台空台面和另一型振动台带滑台的模型辨识结果,并通过正弦扫频试验实例给出了模型验证.结果表明,该算法辨识精度高,收敛速度快,鲁棒性强,抗噪声能力强,在电动振动台系统辨识上能取得良好的效果.