地下铁磁物体的分步磁定位方法

针对地下铁磁物体埋藏深度大、测量范围受限、各种干扰因素多、与周围介质间磁性差异小难以定位的情况,提出-种分步磁定位方法.首先根据不同深度面上所有测量点的磁场突变值确定铁磁物体顶端所处深度,再利用磁梯度异常和磁场随距离衰减规律实现对磁性体顶端位置的准确定位.实际工程应用表明:该方法对于地下铁磁物体具有定位准确和成本低廉的优势.     

The Effect of Nanotube Content and Orientation on the Mechanical Properties of Polymer–Nanotube Composite Fibers: Separating Intrinsic Reinforcement from Orientational Effects

We have measured the mechanical properties of coagulation‐spun polymer–nanotube composite fibers. Both the fiber modulus, Y, and strength, σ_B, scale linearly with volume fraction, V_f, up to V_f ～10%, after which these properties remain constant. We measured dY/dV_f = 254 GPa and dσ_B/dV_f = 2.8 GPa in the linear region. By drawing fibers with V_f < 10% to a draw ratio of ～60%, we can increase these values to dY/dV_f = 600 GPa and dσ_B/dV_f = 7 GPa. Raman measurements show the Herman's orientation parameter, S, to increase with drawing, indicating that significant nanotube alignment occurs. Raman spectroscopy also shows that the nanotube effective modulus, Y_Eff, also increases with drawing. We have calculated an empirical relationship between the nanotube orientation efficiency factor, η_o, and S. This allows us to fit the data for Y_Eff versus η_o, showing that the fiber modulus scales linearly with η_o, as predicted theoretically by Krenchel. From the fit, we estimate the nanotube modulus to be; Y_NT = 480 GPa. Finally, we show that the fiber strength also scales linearly with η_o, giving an effective interfacial stress transfer of τ = 40 MPa and a nanotube critical length of l_c=1250 nm. This work demonstrates the validity of the Cox‐Krenchel rule of mixtures and shows that continuum theory still applies at the near‐molecular level.     

Negative giant surface potential of vacuum-evaporated tris(7-propyl-8-hydroxyquinolinolato) aluminum(III) [Al(7-Prq)3] film

Negative giant surface potential was realized in a vacuum-evaporated film of tris(7-propyl-8-hydroxyquinolinolato) aluminum(III) [Al(7-Prq)₃]. Electroabsorption response of the film presented an inverted polarity to that of tris(8-hydroxyquinolinolato) aluminum (Alq₃), suggesting opposite noncentrosymmetry of molecular orientation. Asymmetric dice model with molecular geometric effect has been proposed, and propyl substitution at 7 position of the ligands was indicated to affects the molecular posture on the surface to invert the polarity of noncentrosymmetry. Our results opened a new possibility of controlling molecular orientation in a film for device applications.     

基于ER模型的军交运输保障装备管理多维数据模型

针对军事交通运输保障装备管理（Military Transportation Indemnificatory Equipment Management,MTIEM）数据结构复杂、层级较多的特点,从多维数据模型相关理论入手,以ER模型为基础,论述层次主键模型（Hierarchy Principal Key Model,HPKM）构建方法,并将其向多维模型转换,提出其多维数据模型构建方法,为联机分析处理提供支撑。     

激光毛化对镀铬层结晶位向及摩擦磨损性能的影响

针对激光毛化提高镀铬层硬度和耐磨性的现象,采用X-衍射测试不同状态铬层晶粒位向,利用晶粒密排面的排列位向定性分析铬层织构改变情况。结果表明,基体经毛化处理产生的高密度位错和表面形貌改善了电镀铬层织构,是使铬层硬度、耐磨性能提高的重要原因。     

搜索域自适应的蒙特卡洛单像空间后方交会方法

针对在大角度摄影中,光束平差法将导致外方位元素求解发散或收敛至局部最优解问题,提出搜索域自适应的蒙特卡洛单像空间后方交会方法。通过建立蒙特卡洛搜索域与摄影角间的数学模型,基于现有3个控制点的角锥体外方位元素初始值解法,解得正确的外方位元素。实验与分析结果表明,该方法稳定性好,结果精度高,适于解算大角度摄影下的外方位元素。     

基于角增量提取改进算法的旋转矢量法

旋转矢量法应用于角速率陀螺时,将角速率转化为角增量产生了较大误差,为使旋转矢量法有效地应用于角速率陀螺的姿态解算,该文提供了一种改进的三子样旋转矢量法。该方法在经典三子样角增量提取算法上,增加了前后各1／3周期的节点,使得采样值更加有效利用。在不增加区问子样数的前提下,使每个有效节点至少被使用5次,大大降低了角速率向角增量转化的误差。仿真结果表明,该算法可以有效应用于角速率陀螺。     

用于SAW器件的C轴择优取向LiNbO3薄膜的制备及结构研究

采用射频（RF）磁控溅射法在金刚石（111）衬底上沉积LiNbO3（LN）薄膜,借助X射线衍射技术（XRD）,研究了外加偏压（0～80V）和衬底温度（200～500℃）等工艺参数对LiNbO3薄膜结构和取向性的影响。实验结果表明,在衬底温度为200℃、外加偏压为～80V的T艺条件下,LiNbO3的（006）衍射峰强度超过LN的（012）衍射峰强度,在金刚石（111）衬底上获得较高c轴取向的LN薄膜。并且对C轴择优取向LN薄膜的形成机理进行了探讨。     

Study of hybrid orientation structure wafer

Two types of 5μm thick hybrid orientation structure wafers,which were integrated by（110）or（100） orientation silicon wafers as the substrate,have been investigated for 15-40 V voltage ICs and MEMS sensor applications.They have been obtained mainly by SOI wafer bonding and a non-selective epitaxy technique,and have been presented in China for the first time.The thickness of BOX SiO₂ buried in wafer is 220 nm.It has been found that the quality of hybrid orientation structure with（100）wafer substrate is better than that with（110）wafer substrate by"Sirtl defect etching of HOSW".     

基于梯度离散度和互信息准则的残缺指纹方向场重建融合算法

针对残缺指纹中方向场的重构,本文提出了一种利用全局方向信息和局部梯度信息的基于互信息准则的方向场融合算法此算法根据局部梯度信息的竞争性、结合全局方向信息的互补性、冗余性,首先根据局部指纹梯度信息定义离散度,自适应的融合梯度信息,其次运用互信息准则结合指纹全局信息,对残缺部分的方向进行重估和修正根据融合结果,进行后期指纹...