现阶段网通公司通信线路整治的标准和意义

本文以济宁市网通线路工程整治为实例,分析了在当前电话用户相对稳定的情况下,通信公司再加大对通信线路工程整治的必要性、重点和意义.     

基于GPRS技术的远程数据传输系统的研究

一、GPRS技术蜂窝移动通信方式利用频率复用技术有效地实现了频率资源的利用,而且在全国范围内,网络覆盖率高。所以,充分利用现有的蜂窝网实现无线数据传输业务是一种既有效又经济的手段,而基于GPRS的分组数据传输则是最经济实用的。     

基于向量小波变换及Fisher算法的红外弱小目标检测

提出了一种新的红外图像弱小目标检测方法;即利用向量小波的优良性质,采用恰当的预滤波器对图像进行预处理;而后对经向量小波变换得到的高频图像利用Fisher算法进行分割,最终将目标从背景中分离出来.通过理论分析和大量实验,表明了算法是有效的,并证明该算法能够快速稳定的检测出信噪比小于等于2的弱小目标.     

Ultrafast Magnetization Precession in Perpendicularly Magnetized L1_0-MnAl Thin Films with Co_2 MnSi Buffer Layers

Perpendicularly magnetized L1₀-MnAl thin films with Co₂ MnSi bufer layers were prepared on GaAs(001) substrates by molecular-beam epitaxy(MBE).The samples with high crystalline quality show a maximum uniaxial perpendicular magnetic anisotropy constant of 1.4×10⁷ erg/cm³.Ultrafast spin dynamics with a magnetization precession frequency up to 200 GHz was investigated by using time-resolved magneto-optical Kerr effect(TRMOKE) measurements,from which the G...     

Temperature dependence of spin pumping in YIG/NiOx/W multilayer

We report the temperature dependence of the spin pumping effect for Y₃Fe₅O₁₂ (YIG, 0.9 μm)/NiO (t_NiO)/W (6 nm) (t_NiO = 0 nm, 1 nm, 2 nm, and 10 nm) heterostructures. All samples exhibit a strong temperature-dependent inverse spin Hall effect (ISHE) signal I_c and sensitivity to the NiO layer thickness. We observe a dramatic decrease of I_c with inserting thin NiO layer between YIG and W layers indicating that the inserting of NiO layer significantly suppresses the spin transport from YIG to W. In contrast to the noticeable enhancement in YIG/NiO (t_NiO ≈ 1-2 nm)/Pt, the suppression of spin transport may be closely related to the specific interface-dependent spin scattering, spin memory loss, and spin conductance at the NiO/W interface. Besides, the I_c of YIG/NiO/W exhibits a maximum near the T_N of the AF NiO layer because the spins are transported dominantly by incoherent thermal magnons.     

Magnetic Damping Properties of Single-Crystalline Co55Mn18Ga27 and Co50Mn18Ga32 Films

We investigate the structural,static magnetic and damping properties in two Mn-deficient magnetic Weyl semimetal Co-Mn-Ga(CMG) alloy films,i.e.,Co₅₅Mn₁₈Ga₂₇(CMG1) and Co₅₀Mn₁₈Ga₃₂(CMG2),which were epitaxially grown on MgO(001) substrates.CMG1 has a mixing phase of B₂ and L21,larger saturation magnetization(Ms ～760 emu/cm³),stronger in-plane magnetic anisotropy.CMG2 has an almost pure B₂ phase,small...     

Site Preference of Se and Te in Bi_2Se_(3-x)Te_x Thin Films

The ternary topological insulators Bi₂Se_3-xTe_x have attracted a great deal of attention due to their exotic physical and chemical properties.While most of the studies focus on the properties of these ternary TIs,limited research was performed to investigate the dynamic atomic stack of its crystal structure.We prepared highquality Bi₂Se_3-xTe_x thin films on Ga As(111)B substrates using molecular beam epitaxy,characterized with Raman...     

基于SA4向量小波变换及Fisher算法的红外弱小目标检测

本文提出了一种新的红外图像弱小目标检测方法,即利用SA4向量小波的优良性质,采用恰当的预滤波器对图像进行预处理;而后利用Fisher算法对经SA4向量小波变换得到的高频图像进行分割,最终将目标从背景中分离出来;大量实验表明该算法是有效的。     

非接触静电放电测试低重复特性分析研究

基于自主研发的新型测试系统,对小间隙静电放电(Electrostatic Discharge,ESD)中电极移动速度和气体压强引起放电参数的低重复离散特性进行探讨.新型测试系统采用机电一体化设计,解决了带电体与受电体高速相向运动与避免强烈撞击损坏仪器的难题,并实现对多种影响因素的有效测量.用新型测试系统测量了气体压强变化和向放电靶移动电极速度等放电参数.静电放电模拟器移动距离控制在(10～40 cm)的范围.电极移动速度变化(v)为14 cm/s,则放电电流峰值改变(J)达到0.5A,空气压强变化对放电电流最高峰值的影响十分明显,压强变化(p)为0.06个大气压时,则峰值电流变化(D为0.5A,证明了电极移动速度和空气压强对放电参数产生的影响;对放电参数受电极移动速度和气体压强变化而出现显著差异的可能机制给出了初步分析.     

基于(A)Trous算法的红外序列图像中运动目标的检测与跟踪

主要研究了红外图像中运动点目标的检测及跟踪问题.在复杂背景下,根据小目标在红外影像中容易丢失的特性,利用Atrous小波变换对图像非抽取(变换后图像数据未损失)的优点对红外图像进行了背景抑制与增强.通过聚类分割算法分割出了可疑目标,并采用八邻域分析算法准确跟踪并提取出了运动小目标.试验结果表明,本文算法在对红外序列图像中的运动目标进行检测与跟踪时具有较强的实用价值.