基于石墨烯及其衍生物的信息存储:材料、器件和性能

石墨烯以其独特的二维结构和高的热导电性、高杨氏模量、高电子/空穴迁移率、高抗拉强度、大的布鲁诺尔-埃米特-特勒表面积和量子霍尔效应等优异性能,备受科研工作者的关注,迅速成为材料、化学、物理和工程领域的热点研究课题。与富勒烯(C₆₀、C₇₀)的功能化一样,利用共价键合修饰或非共价键合修饰的方法可以在石墨烯表面或石墨烯体系中引入功能基团或功能组分,制备出种类繁多的具有特殊光、电、磁和生物效应的石墨烯衍生物。以石墨烯作为数据存储介质的分子级别计算已经引发了一场信息技术产业的革命,它能在更小的空间上,使用更少的能源来存储更多的数据信息, 有望成为目前基于硅半导体存储技术的潜在替代或补充技术。基于石墨烯的存储器件展现出优良的数据存储性能、器件稳定性和可靠性,为使这类器件具有更好的实际应用前景,人们采用许多技术手段来调控和优化器件性能。本文综述了近年来引起广泛关注的诸如石墨烯、共价修饰的石墨烯、石墨烯基复合材料、石墨烯/无机材料异质结等基于石墨烯及其衍生物的存储器件及相关材料研究进展,以及石墨烯/还原的氧化石墨烯透明电极在存储器件中的应用。探讨了该领域存在的亟待解决的关键基础问题和未来发展方向。     

A MAP-based algorithm for spectroscopic semi-blind deconvolution

Spectroscopic data often suffer from common problems of bands overlapping and random noise. In this paper, we show that the issue of overlapping peaks can be considered as a maximum a posterior (MAP) problem and be solved by minimizing an object functional that includes a likelihood term and two prior terms. In the MAP framework, the likelihood probability density function (PDF) is constructed based on a spectral observation model, a robust Huber-Markov model is used as spectra prior PDF, and the kernel prior is described based on a parametric Gaussian function. Moreover, we describe an efficient optimization scheme that alternates between latent spectrum recovery and blur kernel estimation until convergence. The major novelty of the proposed algorithm is that it can estimate the kernel slit width and latent spectrum simultaneously. Comparative results with other deconvolution methods suggest that the proposed method can recover spectral structural details as well as suppress noise effectively.     

毛细管电泳-核磁共振联用技术及其应用

毛细管电泳－核磁共振在线联用技术是新型的分离和生命大分子的有效手段之一。详细介绍了在ＣＥ－ＮＭＲ联用技术中最关键的ＮＭＲ对纳升数量级样品的检测技术和最新进展。     

青藏铁路冻土区路基工程安全可靠性监测技术研究

通过对冻土区路基工程和冻土之间相互作用过程的分析,提出冻土区路基工程的安全可靠性监测关键技术一是监测方法,二是监测手段,三是数据分析。冻土区路基工程的安全可靠性首先取决于工程周围和工程基底多年冻土的热稳定性,其次取决于发生变形的路基填土厚度及其基底融化层厚度。因此,路基顶面以下不同深度地温监测和年际冻融季节时段路基土层变形监测是冻土区工程长期可靠性监测的主要指标。青藏铁路自然条件的严酷性,要求监测手段具有可靠性和耐久性以及对复杂自然条件变化的适应性。文章提出一种自动观测多年冻土地温和路基变形,并能够实现数据无线传输的现场监测系统设计方案,通过现场试验,证明这种监测系统能够适应青藏高原恶劣的自然条件,减轻了人工监测的劳苦,具有可靠性和耐久性。作者还提出了能够简便判断冻土区工程安全可靠性的监测数据分析方法,对目前冻土区工程安全可靠性分析具有一定的理论指导作用。     

Multiframe blind image deconvolution with split Bregman method

In the paper, a multiframe blind image deconvolution method based on total variation and framelet regularizer is proposed. An adapted version of the split Bregman method is proposed to efficiently solve the resulting minimization problems. In each iteration, four sub-problems need to be solved, one of which can be very efficiently and easily solved via fast Fourier transform implementation or closed form solution. Both simulated noisy and blurred frames and real degraded frames are used to verify the effectiveness of the proposed method. Comparative experimental results show that the proposed method can efficiently remove the blur and noises and restore high quality sharp image.     

超高压水射流喷头水动力特性研究

基于对超高压水射流喷头的外部参数定量化分析,给出关于射流核心参数的优选方法,旨在提高水射流效率。首先,根据超高压水射流除锈喷嘴的工作特点,考虑到水的压缩性和空化效应,建立单束定冲角、多束旋转喷头的三维数值模型,通过改变靶距、入射角度、转速等外部特征参数,实施了超高压水射流除锈喷头水动力性能模拟研究。然后,重点分析单束定冲角喷嘴靶距、入射角度对靶面剪切应力、打击压强分布的影响,以及射流等速核长度与最佳射流靶距的关系。发现当靶距等于喷嘴射流等速核长度时,壁面剪切应力达到最佳水平。此外,通过分析高速旋转射流卷吸效应、靶面水垫作用对靶面所受剪切应力、打击压强分布的影响,得到最佳转速范围和对应线速度。初步阐明了射流冲击剥离的机理、单束定冲角以及多束旋转射流的特征参数对射流效果的影响,可为超高压除锈喷头的设计、装配提供参考。     

Blind image deconvolution with spatially adaptive total variation regularization

A blind deconvolution algorithm with spatially adaptive total variation regularization is introduced. The spatial information in different image regions is incorporated into regularization by using the edge indicator called difference eigenvalue to distinguish edges from flat areas. The proposed algorithm can effectively reduce the noise in flat regions as well as preserve the edge and detailed information. Moreover, it becomes more robust with the change of the regularization parameter. Comparative results on simulated and real degraded images are reported.     

微波辅助萃取-气相色谱质谱法测定丙烯酸树脂中9种残余单体

建立了丙烯酸树脂中9种残余单体(丙烯酸甲酯、丙烯酸乙酯、甲基丙烯酸甲酯、甲基丙烯酸乙酯、丙烯酸丁酯、甲基丙烯酸丁酯、苯乙烯、丙烯酸、甲基丙烯酸)的微波辅助萃取-气相色谱-质谱检测方法。固体丙烯酸树脂样品用乙酸乙酯微波萃取后加甲醇沉淀(液态丙烯酸树脂样品直接用甲醇稀释)后,采用DB-WAX毛细管柱分离。结果表明,本方法在20 min内同时分离了9种单体,所测物质的定量限(LOQ,以信噪比为10计)为3～50 mg/kg(固体树脂)和1～10 mg/kg(液态树脂);在1～500 mg/L范围内,线性相关系数均在0.995以上;在5个添加水平下平均回收率为84.4%～108.6%,相对标准偏差(n=6)为0.27%～4.97%。方法的灵敏度和回收率高、选择性好,能满足实际工作的要求。     

Saliency model for object detection: searching for novel items in the scene

This Letter presents a new computational model of visual saliency. A new definition for saliency is proposed: saliency is novelty, which guides the deployment of visual attention. We define novelty as coming from regions that contain dissimilarities from the global scene. Our approach consists of two stages: First, obtain a global perspective. The global representation is obtained with a visual vocabulary. A novelty factor for each visual word is introduced according to the "repetition suppression principle." Second, obtain a local perspective. A local representation is achieved from the histogram of visual word occurrence. The metric of saliency is defined as the overall novelty factor of the visual words. Experimental results demonstrate good performance of the proposed model on complex scenes and fair consistency with human eye fixation data.