一种面向H.264 KTA的快速分数运动估计方法

H.264 KTA（key technology area）在提供更高视频编码性能的同时,也大大地增加了视频编码的计算复杂度。其中,1/8像素运动补偿技术和分数点自适应插值滤波技术的采纳使分数点运动估计占用总体编码时间的比例越来越大。提出一种快速分数点运动估计算法。该算法利用分数点残差曲面的单峰特性和整分数运动向量的相关性,优化搜索模板和搜索的起始位置。根据在H.264 KTA上的实验结果显示,新算法在大幅提高计算速度的同时,保持了与全分数点运动估计算法相当的率失真性能。     

SiCp／ZA30复合材料摩擦磨损特性研究

研究了ＳｉＣｐ／ＺＡ３０复合材料的摩擦磨损特性。结果表明：ＳｉＣｐ／ＺＡ３０复合材料的耐磨性优于高铝锌基合金，并随ＳｉＣ粒子加入量的增加而增大。     

建筑力学原理在陶瓷造型设计中的应用

陶瓷造型设计要达到经济、实用和美观的要求,必须要掌握陶瓷产品从泥巴成型到烧成的整个流程中的工艺操作,其中包括力学问题。为了解决陶瓷作品在生产中受力而容易产生变形、开裂难题,经过反复研究实验,并将建筑力学的框架结构受力原理运用于陶瓷的造型设计中,终于取得了成功,解决了这一难题,并取得了良好的经济效益。     

MAC-layer rate control for 802.11 networks: a survey

Rate control at the MAC-layer is one of the fundamental building blocks in many wireless networks. Over the past two decades, around thirty mechanisms have been proposed in the literature. Among them, there are mechanisms that make rate selection decisions based on sophisticated measurements of wireless link quality, and others that are based on straight-forward heuristics. Minstrel, for example, is an elegant mechanism that has been adopted by hundreds of millions of computers, yet, not much was known about its performance until recently. The purpose of this paper is to provide a comprehensive survey and analysis of the existing solutions from the two fundamental aspects of rate control—metrics and algorithms. We also review how these solutions were evaluated and compared against each other. Based on our detailed studies and observations, we share important insights on future development of rate control mechanisms at the MAC-layer. This discussion also takes into account the recent developments in wireless technologies and emerging applications, such as Internet-of-Things, and shows issues that need to be addressed in the design of new rate control mechanisms suitable for these technologies and applications.

     

Low-temperature epitaxy of transferable high-quality Pd(111) films on hybrid graphene/Cu(111) substrate

Nano Research - The continuous pursuit of miniaturization in the electronics and optoelectronics industry demands all device components with smaller size and higher performance, in which thin metal...     

邻近隧道盾构施工的现场实测分析

为研究新建隧道对既有隧道的附加作用,本文通过现场监测,从附加应力、附加变形两方面研究了新建盾构隧道施工对既有隧道的附加作用。分析了既有隧道管片附加作用的动态变化规律,给出了附加作用与掌子面距离的关系,同时对管片附加作用的空间分布规律进行了分析。监测结果表明:①既有隧道管片的附加环向、径向应力远大于附加走向应力。②既有隧道拱顶、拱底处环向附加应力为拉应力,且拱顶处拉应力远远大于拱底处拉应力,两侧拱腰处为压应力,靠近新建侧附加压应力大于远离侧附加应力,前者约为后者的2倍。③既有隧道管片的走向附加应力是压应力,其中拱底处最大,近侧拱腰处次之,拱顶处较小,远侧拱腰处最小。④既有隧道管片的径向附加应力为压应力,大小为0.1~0.5 MPa,近侧拱腰处最大,远侧拱腰处次之,拱顶较小,拱底最小。其表现为“侧向大,竖向小”“近大远小,上大下小,不对称”的分布规律,即逆时针旋转90°的“非对称葫芦形”分布。⑤附加地表沉降呈对称U型沉降槽分布,影响半径为1倍埋深,影响角约45°,沉降最大点在隧道正上方,当掌子面到达监测断面时沉降速率最大。⑥既有隧道管片的附加净空收敛值依次经历了侧向收缩、缓慢扩张、快速扩张、缓慢回落,趋于稳定5个阶段。净空收敛值回落至峰值的三分之一,其变化范围在-1~3 mm。⑦既有隧道管片的附加拱底沉降依次为上浮、回落、快速上浮、快速回落、回落至初始状态,其变化范围为-1.0~2.5 mm。     

聚苯乙烯反应器国产化可行性分析

通过剖析聚苯乙类装置进口反应器技术特性、结构特点,对聚苯乙烯反应器国产化可行性进行了分析。     

Universal Imaging of Full Strain Tensor in 2D Crystals with Third‐Harmonic Generation

Quantitatively mapping and monitoring the strain distribution in 2D materials is essential for their physical understanding and function engineering. Optical characterization methods are always appealing due to unique noninvasion and high‐throughput advantages. However, all currently available optical spectroscopic techniques have application limitation, e.g., photoluminescence spectroscopy is for direct‐bandgap semiconducting materials, Raman spectroscopy is for ones with Raman‐active and strain‐sensitive phonon modes, and second‐harmonic generation spectroscopy is only for noncentrosymmetric ones. Here, a universal methodology to measure the full strain tensor in any 2D crystalline material by polarization‐dependent third‐harmonic generation is reported. This technique utilizes the third‐order nonlinear optical response being a universal property in 2D crystals and the nonlinear susceptibility has a one‐to‐one correspondence to strain tensor via a photoelastic tensor. The photoelastic tensor of both a noncentrosymmetric D_3h WS₂ monolayer and a centrosymmetric D_3d WS₂ bilayer is successfully determined, and the strain tensor distribution in homogenously strained and randomly strained monolayer WS₂ is further mapped. In addition, an atlas of photoelastic tensors to monitor the strain distribution in 2D materials belonging to all 32 crystallographic point groups is provided. This universal characterization on strain tensor should facilitate new functionality designs and accelerate device applications in 2D‐materials‐based electronic, optoelectronic, and photovoltaic devices.     

SiC颗粒对铝基合金摩擦磨损性能的影响

研究了ＳｉＣ颗粒增强铝基复合材料的摩擦磨损特性，结果表明：ＳｉＣ特性的加入提高了材料的耐磨性，并随ＳｉＣ粒子加入量的增加耐磨性增大     

陶瓷双层蓄水茶盘的创作体会

传统的泡茶茶具,对于废水的处理和卫生等方面都存在着诸多的问题,为了解决这些问题,我通过大量的实践潜心研制的双层蓄水茶盘,从其结构上能很好地处理废水,同时在冲洗茶盘盘面时也能达到清洁的目的