巨磁电阻特性的研究及其在物理实验教学上的应用

阐述了巨磁电阻效应的机理,利用AA002系列巨磁电阻(GMR)器件测量了单个巨磁电阻的阻值与磁场磁感应强度的关系以及AA002系列巨磁电阻(GMR)器件的输出电压与外磁场的关系,研究了巨磁电阻效应的特性,并设计了巨磁电阻器件在物理实验教学中的实用性比较广泛的系列实验.     

一种具有正弦基函数权值的反馈型神经网络模型

提出了一种新的两层反馈型神经网络模型. 该网络采用正弦基函数作为权值, 神经元激活函数为线性函数, 连接形式为两层反馈型结构. 研究并定义了该反馈型神经网络的能量函数, 分析了网络运行的稳定性问题, 并证明了在Liapunov意义下网络运行的稳定性. 网络运行过程中, 其权值不做调整(但随时间按正弦规律变化), 网络状态不断地转换. 随着网络状态变化其能量不断减小, 最终在达到稳定时能量到达极小点. 由于该反馈型神经网络权值为正弦函数, 特别适合于周期信号的自适应逼近和检测, 为实际中周期性信号检测与处理提供了一种新的、有效的网络模型和方法. 作为应用实例把该网络应用于电力系统中电压凹陷特征量实时检测, 仿真结果表明, 网络用于信号检测不仅有很高的静态精度, 而且有非常好的动态响应特性.     

A possible mechanism for magnetar soft X-ray/γ-ray emission

Once the energies of electrons near the Fermi surface obviously exceed the threshold energy of the inverse β decay,electron capture(EC) dominates inside the magnetar.Since the maximal binding energy of the 3 P 2 neutron Cooper pair is only about 0.048 MeV,the outgoing high-energy neutrons(E k(n) > 60 MeV) created by the EC can easily destroy the 3 P 2 neutron Cooper pairs through the interaction of nuclear force.In the anisotropic neutron superfluid,each 3 P 2 neutron Cooper pair has magnetic energy 2μ n B in the applied magnetic field B,where μ n = 0.966 × 10 23 erg.G 1 is the absolute value of the neutron abnormal magnetic moment.While being destroyed by the high-energy EC neutrons,the magnetic moments of the 3 P 2 Cooper pairs are no longer arranged in the paramagnetic direction,and the magnetic energy is released.This released energy can be transformed into thermal energy.Only a small fraction of the generated thermal energy is transported from the interior to the surface by conduction,and then it is radiated in the form of thermal photons from the surface.After highly efficient modulation within the star’s magnetosphere,the thermal surface emission is shaped into a spectrum of soft X-rays/γ-rays with the observed characteristics of magnetars.By introducing related parameters,we calculate the theoretical luminosities of magnetars.The calculation results agree well with the observed parameters of magnetars.     

Influence of a two-dimensional electron gas on current-voltage characteristics of Al_0.3Ga_0.7 N/GaN high electron mobility transistors

The J-V characteristics of AltGa1 tN/GaN high electron mobility transistors(HEMTs) are investigated and simulated using the self-consistent solution of the Schro¨dinger and Poisson equations for a two-dimensional electron gas(2DEG) in a triangular potential well with the Al mole fraction t = 0.3 as an example.Using a simple analytical model,the electronic drift velocity in a 2DEG channel is obtained.It is found that the current density through the 2DEG channel is on the order of 1013 A/m2 within a very narrow region(about 5 nm).For a current density of 7 × 1013 A/m2 passing through the 2DEG channel with a 2DEG density of above 1.2 × 1017 m-2 under a drain voltage Vds = 1.5 V at room temperature,the barrier thickness Lb should be more than 10 nm and the gate bias must be higher than 2 V.     

还原聚苯胺插层氧化石墨纳米材料修饰电极用于抗坏血酸测定的研究

本文研制成还原聚苯胺插层氧化石墨纳米材料(R-(PAI/GO))修饰电极,并用于测定抗坏血酸(AA)。在pH5.02的Brinton-Robinson(B-R)缓冲溶液中,AA可在R-(PAI/GO)修饰电极上产生一对氧化还原峰,该峰的峰电流与AA浓度的对数在1.0×10-9~4.24×10-2mol/L范围呈良好的线性关系,相关系数为0.9910。多巴胺(DA)等物质对AA的测定无干扰。该电极制作简单,有良好的稳定性和重现性,用于实际试样中AA的测定,结果满意。     

电子散斑实验数字化软件的设计

将电子散斑干涉测量技术引入物理实验教学中,为实现电子散斑的数字化,编写了功能齐全的处理软件,可以根据实验环境的不同对散斑图进行不同的预处理,使在尽可能不损失图像重要信息的基础上降低噪声,提高信噪比.     

涡轮叶栅尾迹对二次流影响的试验研究

本文利用运动圆柱排模拟上游叶片尾迹,在平面涡轮叶栅上研究了上游尾迹与叶栅通道内二次流相互作用,初步讨论了尾迹与二次流相互作用的机理,研究发现利用这种相互作用可以控制二次流的强度、减小二次流损失,进而可实现提高涡轮效率的目的.     

Effect of Phosphate on the Self-Assembly of Peptide EMK16-Ⅱ

The ionic-complementary peptide EMK16-Ⅱ is used to investigate the effects of hydrophobic and electrostatic interactions on the self-assembling process by atomic force microscopy and circular dichroism spectra. It is found that the increase of hydrophobicity of the peptides promotes the aggregation of fibrils in pure water. The effects of phosphate with different concentrations on electrostatic interactions are also investigated. It is found that the self-assembling process is enhanced at a low concentration of phosphate and more ordered fibrillar aggregates are formed. When the concentration of phosphate increases to a certain value （9mM）, only a few fibrils are found to be formed. No fibrils but amorphous aggregates exist when the concentration further increases. A physical interpretation is presented such that one divalent anion can interact with two positively charged residual groups in different peptide molecules like a ＂bridge＂ which destroys the ionic-complementary feature and largely inhibits the formation of ordered fibrils.     

一种广义模糊补运算和相应的广义模糊熵

介绍广义模糊补的公理化定义，给出一种构造广义模糊补的方法，运用此方法构造出一种性质良好的广义模糊补；在此基础上提出一种广义模糊熵，这种广义模糊熵的最大值点可以在（0，1）开区间内自由移动。给出一类广义模糊熵的计算公式,便于实际应用。