交流粉末电致发光体的老化研究

本文通过离子探针实验首次证实了电致发光老化过程中铜离子由晶格最深部向颗粒表面迁移的事实.这结论与正电子湮灭寿命谱,顺磁共振实验所得结论是相互支持的.实验结果还表明,经过退火和淬火的材料,铜在颗粒中分布发生了变化,析出的铜聚集在颗粒表面上.形成了高场所必需的硫化锌-硫化铜结,增加了势叠高度和场分布的不均匀性,减缓老化过程中铜离子由晶格内部向表面的迁移,因而改善了电致发光老化. 改进后的材料,在5kHz,200V激发下,发光屏初始亮度为450cd/m2,老化4000小时后,亮度为125.5cd/m2.若改用喷屏法制屏,增大介质的介电常数,发光屏初始亮度最大值可达766cd/m22.     

粉末交流电致发光应用新领域—特殊波长光的暗室照明

根据不同的感光胶片对特种波长光感光灵敏度低和电致发光单色性的特点，研制出系列暗室照明光源和显示器件。研究方法是改变Ⅱ－Ⅵ族化合物半导体的禁带宽度和杂质能级深度。首先做出单色光，再加有机染料使光谱窄化，使达到安全照明与显示的目的。     

审题定位，提高解题能力——以2004年考研数学试卷为基点

本以2004年硕士研究生数学入学试卷典型试题为基础，对如何提高应试中审题的正确性进行了探讨，强调了全方位审题及培养综合思维能力对提高解题能力的重要性。     

滤波窗的选择对傅里叶变换轮廓术测量精度的影响

比较了在有噪声和无噪声的情况下，傅里叶变换轮廓术中采用三种频域滤波窗对测量精度的影响。给出了在有噪声和无噪声情况下。FTP中采用不同滤波窗的测量误差分布图。得出在无噪声及噪声较小的情况下，采用平顶高斯滤波窗测量面形精度最高，而在噪声较大的情况下，采用汉宁滤波窗测量面形精度最高.     

High-accuracy measurement for small scale specular objects based on PMD with illuminated film

In this paper we describe an approach to measure small glossy objects by illuminated film based on Phase Measuring Deflectometry (PMD) system. In this setup, the standard sinusoidal fringe patterns are produced by the photographic film frame (135-film), which is illuminated from behind using LED and diffuser, instead of the well-known LCD monitor plane or digital projector. This setup can avoid the influence of electronic noise and screen refreshing, and fulfill the test of small objects in low cost. Moreover the system is easily calibrated with its vertical setup. With the experiments of measuring a plastic contactless smartcard and a metal plate, it is proven that the setup can reach sub-micrometer accuracy with respect to the data of the Wyko white light interferometer. This setup will be promising in the small scale measurement field.     

Key rotation multiplexing for multiple-image optical encryption in the Fresnel domain

We introduce a key rotation multiplexing method into the double random phase encoding system for multiple-image optical encryption in the Fresnel domain. Each plaintext is encoded into a stationary-white-noise ciphertext by the same only phase mask located at the input plane, and another only phase mask with a certain rotation angle located at the transform plane. All ciphertexts encoded from different plaintexts are added together to produce a final ciphertext, which serves as a single data source for different plaintexts decryption. Thus, the mask located at transform plane can be utilized to decrypt different plaintexts with a certain rotation angle. Also, we perform computer simulations to investigate how the quantization level of decrypted key and CCD, respectively, affect the decrypted quality and the number of images that can be multiplexed.     

The preparation of schwertmannites/mesoporous carbons and its application in simultaneous determination of paracetamol and dopamine

Journal of Solid State Electrochemistry - In this work, mesoporous carbons (MCs) were synthesized by a template method, and the schwertmannites (Schs) were prepared by a calcination method. They...     

Experimental Analysis of Subscribers’ Privacy Exposure by LTE Paging

Wireless Personal Communications - Over the last years, considerable attention has been given to the privacy of individuals in wireless environments. Although significantly improved over the...     

线结构光三维测量系统中旋转轴的标定方法

为简化旋转轴心线的定位,提出了一种基于平面参照物的现场标定方法.将一个绘制有棋盘格图案的靶标倾斜地放在旋转平台上,控制旋转平台任意旋转几个角度,并拍摄下每个位置处靶标的图片.通过处理这些图片获取靶标上特征点的空间坐标,对这些特征点作圆拟合得到一系列的圆心点,再对这些圆心点作直线拟合,建立起旋转轴的直线方程,完成旋转轴的标定.实验验证了该方法的可行性,实测物体的均方根误差为0.04 mm.     

数字散斑时间序列相关的计算机模拟及系统参数选择

本文分析了数字散斑时间序列相关方法中由于平面沿z轴方向平移而引起的散斑场的平移和缩放，并进行了计算机模拟，得出了决定参考平面间距选取的因素。本文分析的结果将有助于确定数字散斑时间序列相关系统的设计参数，以及系统校准过程中参考平面间距的确定原则，为系统设计提供理论依据和技术方案。