基于变步长的亚像素级Hough变换在钢板影像识别检测中的应用

Hough变换可以使边界检测达到亚像素级别,但需要花费很多时间。本文提出一种具有指定精度且可变步长的迭代算法,在钢板影像识别检测中进行试验,结果表明:改变步长的亚像素探寻时间效率比整个行程内进行遍寻的亚像素探寻更高。     

浮式竹格栅坝水力特性试验研究

在用于河道整治的建筑物中，浮式格栅坝是其中的一种，它具有结构简单，施工方便，造价低廉等诸多优点，通过直接影响格栅坝下游流速场变化的坝体透水系数ａ、坝体倾角θ、河道水深ｈ、减速率ψ等重要水力参数的试验研究；提供了在不同坝体透水程度、河道平均流速及水深、坝体倾角运行工况下的图表，为格栅坝的设计及运行管理提供了可靠的依据。     

一种用于18位∑△A/D变换器的低通数字滤波器设计

介绍了一种可用于语声信号处理的高性能EllipticBireciprocal结构低通波数字滤波器实现的集成设计方法。充分利用先进半导体工艺的速度，采用硬件复用技术，整个电路的所有运算分化为单步的加减在一带超前进位链的ALU单元上分时进行，由此节省硬件耗费。该滤波器在时域及频域上的性能已在C模拟器上经过验证，能够达到纹波系数小于0．00007dB，阻带衰减大于112dB。     

溶胶—凝胶法制备Al2O3—SiO2陶瓷薄膜的研究

研究了溶胶－凝胶（Ｓｏｌ－Ｇｅｌ）法制备Ａｌ２Ｏ３－ＳｉＯ２体系多孔的陶瓷膜过程中的溶胶、凝胶反应，通过冷冻复型法观察到溶胶颗粒的微观形貌，认为组分之间的去极化作用是导致溶胶颗粒团聚的原因，利用ＦＴＩＲ地复合交的热处理过程反应情况进行观察，结果表明，组分各自的相变互不影响，也不发生反应，由此可制得保持各组分特性的Ａｌ２Ｏ３－ＳｉＯ２复合陶瓷薄复合薄膜的ＴＥＭ形貌表明，组分在溶胶状太的去极化作用地致     

两端对纵向耦合谐振器的阻带抑制

O引言 随着通讯产业的发展,对宽带,低损耗的RF滤波器需求越来越大,纵向耦合谐振滤波器就是其中一种非常适合高频的应用SAW器件.它的优点在于具有较大的带宽和较低插损的,缺点是旁瓣较高,产生原因比较复杂,无法用一种简单的方法有效地抑制它.为了提高器件的性能,本文对石英基片上纵向耦合谐振滤波器的一些旁瓣进行了分析,并提出了抑制的方法.     

一步闪蒸CIGS薄膜的结构及性能分析

选择铜铟镓硒(CIGS)四元化合物粉末为蒸发源物质,采用闪蒸法在钠钙硅玻璃衬底上沉积CIGS薄膜,重点研究了蒸发功率对CIGS薄膜结构及性能的影响。采用XRD、SEM、UV-vis及四探针测试仪对薄膜进行表征。结果表明,随着蒸发功率的增加,薄膜结晶度变好,颗粒尺寸变大,可见光的吸收系数接近105 cm-1数量级,而CIGS薄膜电阻率及禁带宽度的变化主要来自于薄膜组分的变化。     

Electrical Spin Injection into the 2D Electron Gas in AlN/GaN Heterostructures with Ultrathin AlN Tunnel Barrier

The spin injection into 2D electron gas (2DEG) in AlN/GaN heterostructures is studied by magneto-transport measurements. An ultrathin AlN layer at the hetero-interface acts as a barrier to form high-quality 2DEG in the triangular quantum well and a tunneling barrier for the spin injection to overcome the conductance mismatch issue. In this study, Hanle signals and inversed Hanle signals are observed, proving that the spin injection is achieved in the 2DEG in the AlN/GaN heterostructure rather than in the interfacial states. The spin-relaxation time in 2DEG at 8 K is found to be as long as 860 ps, which almost keeps constant with bias and decreases with increasing temperature. The spin-relaxation process is illustrated as Rashba spin-orbit coupling dominated D'yakonov Perel’ mechanisms above 8 K. These results show the promising potential of 2DEG in AlN/GaN heterostructures for spin field-effect transistor applications.     

Self‐Polarized BaTiO3 for Greatly Enhanced Performance of ZnO UV Photodetector by Regulating the Distribution of Electron Concentration

ZnO film ultraviolet photodetectors (UV PDs) have always suffered from slow speed and low photosensitivity that restrict their broader applications. To break through those barriers, high‐performance ZnO UV PD based on self‐polarized BaTiO₃ (BTO) is first introduced through a facile one‐step spin‐coating method. Compared with pure ZnO film UV PD with low on/off ratio (65) and slow speed (4.1/7.5 s) at 3 V bias under 350 nm UV light, the BTO‐ZnO bilayer film device exhibits an ultrahigh on/off ratio (14 300) and ultrafast response speed (0.11/5.80 ms), which is much faster than that of the most reported ZnO film‐based UV PDs. The numerical simulation demonstrates that the spatial distribution of electron concentration of ZnO film is regulated by the self‐polarization of BTO film, resulting in low dark current and fast response time of the BTO‐ZnO PD. This work provides a new approach to fabricate high‐performance PDs based on self‐polarized ferroelectric materials.     

基于忆阻的全功能巴甫洛夫联想记忆电路的设计、实现与分析

联想记忆是一种描述生物学习和遗忘过程的重要机制,对构建神经形态计算系统和模拟类脑功能有重要的意义,设计并实现联想记忆电路成为人工神经网络领域内的研究热点。巴甫洛夫条件反射实验作为联想记忆的经典案例之一,其硬件电路的实现方案仍然存在电路设计复杂、功能不完善以及过程描述不清晰等问题。基于此,该文融合经典的条件反射理论和纳米科学技术,提出一种基于忆阻的全功能巴甫洛夫联想记忆电路。首先,基于水热合成法和磁控溅射法制备了Ag/TiO_x nanobelt/Ti结构的忆阻器,通过电化学工作站、四探针测试台和透射电子显微镜联合完成相应的性能测试;接着,利用测试得到的电化学数据,构建了Ag/TiO_x nanobelt/Ti忆阻器的数学模型和SPICE电路模型,并通过客观评价验证模型的精确度;进一步,基于提出的Ag/TiO_x nanobelt/Ti忆阻器模型,设计了一种全功能巴甫洛夫联想记忆电路,通过电路描述和功能分析,论述了该电路能够正确模拟巴甫洛夫实验中2类学习过程和3类遗忘过程;最后,通过一系列计算机仿真和分析,验证了所提方案的正确性和有效性。     

Remote-sensing image fusion using sparse representation with sub-dictionaries

Remote-sensing image fusion aims to obtain a multispectral (MS) image with a high spatial resolution, which integrates spatial information from the panchromatic (Pan) image and with spectral information from the MS image. Sparse representation (SR) has been recently used in remote-sensing image fusion method, and can obtain superior results to many traditional methods. However, the main obstacle is that the dictionary is generated from high resolution MS images (HRMS), which are difficult to acquire. In this article, a new SR-based remote-sensing image fusion method with sub-dictionaries is proposed. The image fusion problem is transformed into a restoration problem under the observation model with the sparsity constraint, so the fused HRMS image can then be reconstructed by a trained dictionary. The proposed dictionary for image fusion is composed of several sub-dictionaries, each of which is constructed from a source Pan image and its corresponding MS images. Therefore, the dictionary can be constructed without other HRMS images. The fusion results from QuickBird and IKONOS remote-sensing images demonstrate that the proposed method gives higher spatial resolution and less spectral distortion compared with other widely used and the state-of-the-art remote-sensing image fusion methods.