射频电导轮廓的概念及应用

提出了粗糙表面射频电导轮廓的概念及物理意义,介绍了与射频电导轮廓相关的技术指标和测量、计算方法,对射频电导轮廓在分析计算粗糙表面射频等效电导率、优化射频微波器件加工工艺流程等方面的应用情况进行了简介。实验表明,研究成果与实测数据相吻合。     

W-Mo合金表面超精密加工的CMP技术研究

阐述了金属化学机械抛光的机理。将半导体制造工艺中的nm级平坦化技术、化学机械抛光技术拓展并应用到W-Mo合金工艺中,在实现精密物理材料表面高平坦度、低粗糙度的前提下,提高W-Mo合金去除速率。采用碱性抛光液进行实验,确定了抛光液的成分;分析了W-Mo合金化学机械抛光中压力、流量、转速、pH值、活性剂等参数对W-Mo合金的影响。实验表明,实现W-Mo合金表面超精密抛光的最佳条件为:压力0.06MPa,流速160mL/min,转速60r/min,pH值10.1~10.3。     

焦耳热作用下共晶锡铋焊点电迁移特性

电迁移可以引发芯片内部互连金属引线(单一元素)中的原子或离子沿电子运动方向移动.但是,在共晶锡铋焊点中,组成的元素为锡和铋而非单一元素.由于铋原子和锡原子在高电流密度下具有不同的迁移速率,因此共晶锡铋钎料具有独特的电迁移特性.实验中采用的电流密度为104A/cm2,同时焦耳热会引发焊点温度从25升高至49℃,富铋相在此温度下会发生明显粗化,除此之外,铋原子会首先到达正极界面处并形成坚硬的阻挡层,使得锡原子的定向运动受到阻碍,最终,富锡相会,凸起,其与负极界面问会有凹谷形成.     

胶体硒化镉量子点的荧光时间分辨谱研究

使用化学胶体法合成了12个高质量、不同尺寸的胶体硒化镉量子点.测量了样品的时间分辨光致发光谱、TEM谱,同时测量并计算了样品的光致发光量子产率以及光致发光寿命.研究结果表明:硒化镉量子点的光辐射强度与表面相关的光辐射强度均由量子点的表面缺陷形式决定,并且也决定了光致发光量子产率、光致发光寿命.量子点的表面缺陷形式决定于尺寸,在量子点的生长过程中存在的表面的优化/重构也依赖于尺寸.     

非球面拼接测量中偏置误差修正模型

为解决非球面拼接测量时两子孔径重叠区精确拟合问题,根据波像差理论推导了子孔径干涉测量二次曲面偏置误差与运动自由度之间的函数关系,通过分析得出了偏置误差的作用表现形式与Seidle像差相一致的结论,据此建立了定位机构偏置误差修正模型,提出了一种精确拼接测量二次曲面的像差修正方法,该方法利用最小二乘拟合获得拼接系数,可得到孔径间偏置误差估计值,并可在模型中修正高阶系统像差,提高孔径间重叠区拟合精确度.实验表明,该方法拼接精度高于传统校准三方向调整误差拼接法.     

Parallel Image Processing Technology of Surface Detection System

To improve image processing speed and detection precision of a surface detection system on a strip surface, based on the analysis of the characteristics of image data and image processing in detection system on the strip surface, the design of parallel image processing system and the methods of algorithm implementation have been studied. By using field programmable gate array（FPGA） as hardware platform of implementation and considering the characteristic of detection system on the strip surface, a parallel image processing system implemented by using multi IP kernel is designed. According to different computing tasks and the load balancing capability of parallel processing system, the system could set different calculating numbers of nodes to meet the system＇s demand and save the hardware cost.     

双站SAR的海面速度聚束调制机理研究

为了利用双站SAR对海洋进行研究,首先必须正确理解双站SAR对海面成像的调制机理。而速度聚束调制是SAR所特有的调制机理。该文推导出平飞斜视情况下双站SAR图像平面中方位向强度变化表达式,定量地描述了目标方位位置偏移量和方位向分辨率的下降程度。并在线性近似条件下,求得双站SAR的线性速度聚束调制传递函数。通过仿真分析,定性地给出载机观测条件对双站SAR海浪线性成像范围大小的影响。     

Biocompatible Cubic Boron Nitride: A Noncytotoxic Ultrahard Material

Cubic boron nitride (c-BN) has an ultrahardness and a large bandgap energy like diamond. In the last 30 years, most of the attention has been directed towards the mechanical and electronic applications of c-BN, while its biological potential has been overlooked. The authors report in vitro biocompatibility of high-quality c-BN films prepared by plasma-enhanced chemical vapor deposition using the chemistry of fluorine. c-BN films become superhydrophilic when chemical-treated in hydrogen and nitrogen plasmas with or without the impact of low-energy ions due to a marked increase in polar part of the surface free energy by removal of the fluorine atoms terminating c-BN surfaces. Satisfactory proliferation and differentiation of osteoblastic cells comparable with a control sample and a superhydrophilic nanocrystalline diamond film, and the formation of mineral deposits by biomineralization are confirmed on the superhydrophilic c-BN films with negative values of zeta potential. The results demonstrate a high potential of c-BN as a noncytotoxic ultrahard coating material for biological and biomedical applications.     

Reconstructed Water Oxidation Electrocatalysts: The Impact of Surface Dynamics on Intrinsic Activities

Electroreduction of small molecules such as H₂O, CO₂, and N₂ for producing clean fuels or valuable chemicals provides a sustainable approach to meet the increasing global energy demands and to alleviate the concern on climate change resulting from fossil fuel consumption. On the path to implement this purpose, however, several scientific hurdles remain, one of which is the low energy efficiency due to the sluggish kinetics of the paired oxygen evolution reaction (OER). In response, it is highly desirable to synthesize high-performance and cost-effective OER electrocatalysts. Recent advances have witnessed surface reconstruction engineering as a salient tool to significantly improve the catalytic performance of OER electrocatalysts. In this review, recent progress on the reconstructed OER electrocatalysts and future opportunities are discussed. A brief introduction of the fundamentals of OER and the experimental approaches for generating and characterizing the reconstructed active sites in OER nanocatalysts are given first, followed by an expanded discussion of recent advances on the reconstructed OER electrocatalysts with improved activities, with a particular emphasis on understanding the correlation between surface dynamics and activities. Finally, a prospect for clean future energy communities harnessing surface reconstruction-promoted electrochemical water oxidation will be provided.     

H2 In Situ Inducing Strategy on Pt Surface Segregation Over Low Pt Doped PtNi5 Nanoalloy with Superhigh Alkaline HER Activity

Surface segregation constitutes an efficient approach to enhance the alkaline hydrogen evolution reaction (HER) activity of bimetallic Pt_xNi_y nanoalloys. Herein, a new strategy is proposed by utilizing the small gas molecule of H₂ as the structure directing agent (SDA) to in situ induce Pt surface segregations over a series of PtNi₅-n samples with extremely low Pt doping (Pt/Ni = 0.2). Impressively, the sample of PtNi₅-0.3 synthesized under 0.3 MPa H₂ delivers an extremely low overpotential of 26.8 mV (−10 mA cm⁻²) and Tafel slope of 19.2 mV dec⁻¹, which is superior to most of the previously reported Pt_xNi_y electrocatalysts. This is substantially related to the strong H₂ in situ inducing effect to generate Pt-rich@Ni-rich core-shell nanostructure of PtNi₅-0.3 with an ultrahigh Pt surface content of 46%. The specific mechanistic effects of H₂ during the PtNi₅-n synthesis process are well illustrated based on the combined experimental and theoretical studies. The density functional theory mechanism simulations further unravel that the evolved active site of PtNi₅-n can efficiently reduce the reaction Gibbs free energies; especially for the scenario of PtNi₅-0.3, the downward-shifted d band center of the Pt active site significantly reduces the Pt H bond strength, eventually resulting in the lowest absolute value of ΔG_H.