虚拟软件工厂教学模式的缺陷及其对策

虚拟软件工厂教学模式是一种项目驱动的教学方法,从软件工厂真实性、项目的实战性和师资三个方面分析了虚拟软件工厂教学模式的缺陷,并提出了相应的解决对策。     

一种新型动力学神经网络的理论算法研究

静态神经网络缺乏动力学行为,动态神经网络由微分方程描述,神经元具有反馈环,更适合描述动态系统.以前的研究中所提出的一些改进的递归网络中引入的都是输入层到关联层的反馈或是输出层到输入层的反馈,但是这些反馈系数是常数,是不可调的,限制了网络反映动态性能的能力.为此,提出了一种由带有积分器和可调反馈系数的神经元构成的动力学神经网络,并利用梯度下降法得到了网络的学习算法.     

炭基锌锰铜煤气脱硫剂的硫化行为研究

对锌、锰、铜摹单金属和复合金属氧化物脱硫剂的脱硫性能进行了讨论,并对炭材料作为脱硫剂和载体的研究现状进行了分析,同时对活化半焦作为脱硫剂载体的可行性进行了探讨.认为复合金属氧化物脱硫剂能够发挥单氧化物的优势,并克服其不足.将复合金属氧化物负载于炭材料上,可提高金属氧化物活性组分的利用率,改善脱硫剂的硫化性能,同时降低脱硫剂成本,使炭基锌锰铜复合金属氧化物煤气脱硫剂具有广阔的应用前景.     

变向平面挤压对Al2O3／TiC双颗粒增强铝合金的影响

由原位反应得到的Al203/TiC双颗粒增强铝合金的性能与纯铝相比,其性能有所提高,但是,Al2O3/TiC双颗粒增强铝合金中所存在的长条状、硬而脆的Al3Ti,严重影响了铝合金的综合力学性能.利用变向平面挤压工艺对Al2O3/TiC双颗粒增强铝合金进行挤压,实现大变形,由此打碎了长条状Al3Ti,并且细化晶粒,从而提高了铝合金的综合机力学能.     

乙醇水蒸气重整制氢反应机理及动力学研究进展

概述了乙醇水蒸气重整制氢的反应机理和动力学研究进展。乙醇水蒸气重整制氢动力学,有幂函数速率方程的经验模型及双曲线速率方程的机理模型两大类,其中以表面反应为速率控制步骤(RDS)的机理模型,又分为Langmuir-Hinshelwood机理(L-H机理)和Eley-Rideal机理(E-R机理)模型。也有属于L-H机理的Langmuir-Hinshelwood-Hougen-Watson机理(LHHW机理)模型提出。     

氢气还原合成LiFePO_4的动力学探讨

以H3PO4、Fe2O3和LiOH.H2O为原料,用H2还原合成了橄榄石型LiFePO4材料。采用Rietveld全谱拟合法检测不同温度和时间下LiFePO4的转化率,通过研究其转化率与时间、温度的关系,确定了H2还原合成LiFePO4的反应机理、反应级数和速率常数,并给出了控制步骤的转化温度和各阶段的活化能。根据动力学研究的结果,采用"H2气氛低温合成,N2气氛高温生长"机制合成了LiFePO4/C复合材料。该材料具有单一的橄榄石结构,颗粒尺寸细小均匀,0.1C倍率下,首次放电容量达152.5 mAh/g,放电效率为95.4%,循环30次后,电池的容量保持率达98.4%。     

Preparation of boric acid from low-grade ascharite and recovery of magnesium sulfate

Boric acid and kieserite were prepared from low-grade ascharite by sulfuric acid method. This method results in the recovery of 71.06% and 45.03% for boric acid and kieserite, respectively. Meanwhile, the boric acid was precipitated from the filtrate at low temperature and the solution was recycled without discharging waste liquid in the whole process. The influence of amount of sulfuric acid, mass fraction of sulfuric acid, reaction temperature and reaction time on the leaching rate of boric acid were studied. The results show that the leaching rate of boric acid reaches 93.80% under the following conditions: the amount of sulfuric acid is 85% of theoretical dosage; the mass fraction of sulfuric acid is 25%; reaction temperature is 95 ℃; and the reaction time is 100 min. Meanwhile, the effects of mass fraction of magnesium sulfate, crystallization temperature and crystallization time on the crystallization of kieserite were investigated and the optimal crystallization conditions are obtained: the mass fraction of magnesium sulfate is 28%; the crystallization temperature is 180 ℃ and the crystallization time is 4 h.     

电化学整流电源电磁兼容分析与设计

分析了电化学整流电源中电磁干扰的特点以及带来的影响，有针对性地提出了抑制的可行措施。本文对大功率电力电子设备的电磁兼容性设计有一定的参考价值。     

Numerical simulation of icing effect and ice accretion on three-dimensional configurations

It is common for an aircraft to encounter icing weather conditions, which would be dangerous to the flight. Thus, there is a need to study the detail of icing effect and the process of ice accretion on the aircraft. In this paper, considering three different icing models according to weather conditions, i.e., sharp-angled ice, blunt-nosed ice and double horn ice, the Reynolds-averaged N-S equations and the S-A turbulence model are used to analyze the flow field for an iced wing/body configuration with a multi-block strategy and structured grid technique. The numerical result is compared with the experimental data. A flow solver is developed based on the Euler equations to investigate the ice accretion process. The droplets are tracked by using the Lagrangian method. In addition, a revised Messinger model is proposed to simulate the ice accretion. This numerical simulation is conducted for the ice accretion on an M6 wing and a wing/body/tail configuration. The presented results preliminarily show that the numerical methods are feasible and effective.