涂饰加工对牛皮鞋面革电导率的影响

在1．01×10^5Pa、相对湿度60％情况下，研究了涂饰加工对铬鞣牛皮鞋面革电导率的影响。通过利用自制皮革电导率测试仪对比测试涂饰前后皮革的电导率发现，涂饰加工能够显著改变皮革材料的电阻率，利用聚胺脂涂饰剂，通过涂饰加工过程使皮革材料的电阻率提高了3．6倍。可以通过比较涂饰前后皮革的电导率变化来检测涂层的质量，判断涂饰加工的效果，从而为检测涂层质量提供了一种无损、快速、方便、简单的物理方法。     

Wall charge characteristics in accordance with square and ramped reset pulse in alternating current plasma display panels (AC-PDPs)

The characteristics of wall charge after squared and ramped reset pulse have been experimentally investigated in an AC-PDP with a versatile driving simulator (VDS) system, in which arbitrary driving waveforms and sequences can be edited. Rising or falling times of ramped reset pulse have been varied to be 0, 30, 70, 110 and 150 V under fixed zero falling or rising times, respectively, and the reset voltage is fixed to be 320 V. The longer rising (either falling) times under zero falling (either rising) time in reset pulse make the less IR intensity caused by weak self-discharge that occurred at falling (either rising) time in reset pulse. Generally, the ramped reset pulses have been observed to have large wall voltages of 100 to 200 V while the squared reset pulses are to be 4 V by the weak self-discharges at falling time of reset pulse in this experiment.     

老虑边缘效应直线感应电机矢量控制系统仿真

考虑直线感应电机的动态纵向边缘效应，建立直线感应电机数学模型。利用Simul建立了矢量控制模型，对考虑与不考虑动态纵向边缘效应的仿真结果作了对比，结果证明了考虑边缘效应的正确性与有效性。     

直线感应电机模型分析与直接转矩控制系统仿真

考虑直线感应电机的动态纵向边缘效应，建立直线感应电机数学模型。推导出直线感应电机直接转矩控制的数学模型，用Simulink建立直线感应电机直接转矩控制系统仿真模型，对考虑与不考虑边缘效应的直接转矩控制结果做出比较。结果证明了考虑边缘效应的数学模型正确性与有效性，并且考虑边缘效应后控制系统的动态性能更好。     

电压倍增之像素设计

为了节省面板电路驱动芯片的功率损耗以及制作成本,本研究提出一种新的像素电路设计,而在设计中将会融合电荷泵电路。利用这种电路设计的像素可有效地将像素电极上的驱动电压提高到输入电压的2～3倍以上。此像素电路设计具有两个优势:第一,可以有效降低显示面板的像素功率损耗;第二,不需高电压的面板电路驱动芯片,因此可节省芯片的成本及功率损耗。由模拟结果可知,像素电极上的驱动电压确实可由此像素电路设计而提高到输入电压的2～3倍以上;而像素的功率损耗也可有效地降低,约为传统像素的1/2。     

Orbital Calculations of Kaolinite Surface:on Substitution of Al~(3 ) for Si~(4 ) in the Tetrahedral Sites

The surface properties of kaolinite were determined using density functional theory discrete variational method(DFT-DVM)and Gaussian 03 program.A SiO_4 tetrahedral hexagonal ring with two Al octahedra was chosen to model the kaolinite crystal.The total density of states of the kaolinite cluster are located near the Fermi level at both sides of the Fermi level.Both the highest occupied molecular orbit (HOMO)and the lowest unoccupied molecular orbit(LUMO)of kaolinite indicate that kaolinite system can not only readily interact with electron-acceptor species,but also readily interact with electron-donor species on the edge surface and the gibbsite layer surface,and thus,shows amphoteric behavior.Substitution of Al~(3 ) for Si~(4 ) in the tetrahedral site linking the vacant Al~(3 ) octahedra does not increase the surface chemical reactivity of kaolinite,while substitution of Al~(3 ) for Si~(4 ) in the tetrahedral site with the apex O linking Al~(3 ) octahedra increase the surface chemical reactivity of the siloxane surface of kaolinite,especially acting as electron donors. Additionally,substitution of Al~(3 ) for Si~(4 ) in the tetrahedral site results in the re-balance of charges,leading to the increase of negative charge of the coordinated O atoms of the AlO_4 tetrahedra,and therefore favoring the formation of ionic bonds between cations and the surface O atoms in the basal plane.     

圆筒形薄钢壳物体纵向磁化状态的简化建模方法

积分方程法计算过程中,所得到的系数矩阵是稠密矩阵,随着剖分单元的增多,计算资源的需求将快速增长,可能会在一些实际工程问题的计算中造成一些障碍.根据薄钢板的磁化特点,将圆筒形薄钢壳物体的纵向磁化等效为圆环形体磁化强度分布和圆环形线磁荷分布2种形式,可将原有的二维轴对称问题简化为一维形式,用于快速地建立圆筒形薄钢壳物体纵向磁化状态的数学模型.圆环形体磁化强度分布和圆环形线磁荷分布与三维积分方程法相比,可以得到几乎相同的磁化强度和外部磁场分布,只存在很小的误差.计算结果表明,所得到的新方法只需要少量剖分单元就可以满足计算精度要求,且大大减少了计算资源,加快了计算速度,非常适用于工程计算.     

Modeling and simulation of induction motor drive system to investigate and mitigate of PWM inverter’s adverse effects

Applied high-frequency(HF)switching devicescan cause electromagnetic interferences(EMI)in pow-er electronic converter.It is necessary for an electro-magnetic compatibility(EMC)design to prospect andconsider its possible EMI levels.AC motor drive systems i…     

一种保障变电站蓄电池安全运行的新策略

针对阀控式密封铅酸蓄电池在变电站中的现行运行状况,以温度监控为例,提出了一种保障蓄电池安全运行的新策略.该策略大大提高了变电站用蓄电池的使用寿命及直流系统运行的稳定性,减少了日常维护工作,较大程度地减少了蓄电池发生故障的可能性.     

电子镇流与电容充放电

本文分析了普通电子镇流模型的特点,探讨了电子镇流的最本质特征和其中的电容充放电现象。