纳米电子器件及其集成

对基于Top-Down加工技术的纳米电子器件如：单电子器件、共振器件、分子电子器件等的研究现状、面临的主要挑战等进行了讨论. 采用CMOS兼容的工艺成功地研制出单电子器件，观察到明显的库仑阻塞效应；在半绝缘GaAs衬底上制作了AlAs/GaAs/In0.1Ga0.9As/GaAs/AlAs双势垒共振隧穿二极管,采用环型集电极和薄势垒结构研制的共振隧穿器件，在室温下测得其峰谷电流比高达13.98，峰电流密度大于89kA/cm2；概述了交叉阵列的分子存储器的研究进展.     

基于混酸回流制备碳点的中和过程

Carbon dots (C dots) are relatively novel carbon nanomaterials that have attracted significant interest due to their unique photoluminescence, good biocompatibility, and stability. The preparation methods of C dots was usually summarized into "top-down" and "bottom-up", and mixed acid reflux is a top-down strategy that can be used to synthesize C dots, during which neutralization is a necessary step that can significantly influence the properties and potential applications of the final product. Previously, this research area mainly focused on tuning the properties of C dots by changing the starting materials and/or varying the reaction conditions; the influence of the reagents used during neutralization has been largely ignored. As the previously reported C dots prepared by mixed acid reflux were obtained from different starting materials under varied conditions, a meaningful comparison is difficult. Herein, yellow-emitting C dots were prepared by mixed acid-refluxing a carbon-rich material derived from fullerene carbon soot. For the same batch of as-prepared C dots, the influences of four reagents, i.e., NaOH, Na₂CO₃, K₂CO₃, and NH₃·H₂O, during neutralization on the structures and photoluminescence of the resulting C dots were investigated in detail. The results of thermogravimetric analysis, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy clearly showed that the reagent used during neutralization can affect the degree of dissociation of the acidic functional groups on the C dots. This is further supported by examination of the C dot/surfactant mixtures where subtle changes in the phase behavior were observed. Structural changes of the C dots cause variations in their surface states, ultimately altering the optical characteristics, including UV-vis absorption and fluorescence. Among the treated C dots, the sample prepared with Na₂CO₃ showed the strongest emission under the same excitation wavelength, while that prepared with NH₃·H₂O exhibited a distinct red shift (~8 nm) in the emission curve. The results presented herein provide clear evidence that neutralization reagent selection is important for optimizing the properties of the resulting C dots obtained by mixed acid reflux. In addition, the photoluminescence of the C dots can be influenced by their counterions, providing a novel method for tuning the properties of C dots while explaining their behavior in saline solutions. In short, the basicity of the neutralizing reagent and the type of counterions affect the structure of the C dots surface, which brings different performances. This work reminds researchers that it is necessary to use the type of neutralizing reagent as an experimental condition when preparing C dots in the future.     

纳米加工和纳米电子器件

介绍了电子束曝光技术、EUV光刻技术和X射线光刻技术的进展;对各种纳米电子器件如单电子器件、共振隧穿器件和分子电子器件的研究现状及面临的主要挑战进行了讨论。     

微纳加工技术在微纳电子器件领域的应用

微纳加工技术推动着集成电路不断缩小器件尺寸和提高集成度,光学光刻技术依然是目前的主流微纳加工技术,同时有多种替代技术如电子束直写、极紫外光刻和投影电子束技术,文章介绍了自上而下的微纳加工技术的进展及其在微纳器件研制的重要作用.     

数据元素的标准化方法（4）——数据元素的提取

阐述了数据元素及其基本属性的提取方法.首先详细描述了适用于预建信息系统提取数据元素的"自上而下"提取法,接着给出了适用于已建信息系统的"自下而上"提取法,最后描述了提取数据元素基本属性的步骤.     

垂直纳米线晶体管的制备技术

对目前垂直纳米线晶体管的制备技术进行了综述.首先根据器件结构取向介绍了纳米线晶体管的分类,即水平纳米线晶体管和垂直纳米线晶体管,比较了这两类不同结构晶体管的优缺点,阐述了垂直纳米线晶体管的优势及其潜在应用价值.重点介绍了两种主流的垂直纳米线晶体管的制造方法,即自下而上方法和自上而下方法,自上而下方法则又分为后栅工艺和先栅工艺.随后详细比较了它们之间的不同.最后,对垂直纳米线晶体管制造过程中的工艺挑战进行了分析,提出了几种可行的解决方案,并预测了垂直纳米线晶体管未来的发展趋势,特别是在低功耗器件及3D存储器等方面的发展走向.     

基于ProteinGoggle 2.0的组蛋白H4蛋白质变体的自上而下表征

由于大量可能蛋白质变体以及每一个翻译后修饰大量可能位点的存在,核心组蛋白上密集的组合式翻译后修饰的自上而下表征一直是一个巨大的分析挑战。结合高分辨串级质谱,基于同位素质荷比和轮廓指纹比对的整体蛋白质数据库搜索引擎ProteinGoggle 2.0在组蛋白翻译后修饰的自上而下鉴定方面拥有诸多独特的优势。该文报道ProteinGoggle 2.0对HeLa核心组蛋白H4的数据库搜索及蛋白质变体的鉴定结果。基于从UniProt网站下载的人类核心组蛋白H4的纯文本文件和“鸟枪法”注释,ProteinGoggle 2.0首先创建包含所有可能蛋白质变体的理论数据库;从纯文本文件中提取的信息主要是氨基酸序列、可能的翻译后修饰（单甲基化、二甲基化、三甲基化、乙酰化和磷酸化）及氨基酸变异（A77→P）。在控制质谱水平假阳性率低于1%的前提下,共鉴定到426个蛋白质变体,这是目前为止H4蛋白质变体的最全报道。这些ProteinGoggle 2.0鉴定到的H4蛋白质变体也与之前报道的ProSightPC 2.0的鉴定结果进行了肩并肩比较。总而言之,ProteinGoggle 2.0可以对具有复杂组合修饰及氨基酸变异的蛋白质组进行数据库搜索和蛋白质变体鉴定。     

二维离散余弦变换模块算法及其Hierarchical物理实现

本文阐述了离散余弦变换(DCT)的算法结构及其优化,并基于cadence的EDA平台,诠释了自上而下(Top-Down)的Hierarchical分层次芯片设计理念及方法.     

垂直化、专业化——电信企业组织变革关键词

在未来的一个时期内,国内电信运营商的组织变革将主要围绕两个方面进行:一是加强新兴业务领域和关键运营职能领域的专业化运营,二是强化集团层面的自上而下的垂直管控。     

“自上而下”高分辨串联质谱法分析德谷胰岛素的序列

基于"自上而下"的序列分析策略,采用高分辨串联质谱法对德谷胰岛素的氨基酸序列及B链C末端侧链非蛋白修饰序列进行了全面的分析。优化了德谷胰岛素的还原条件及串联质谱的碰撞条件,结果表明,联合使用50 mmol/L三(2-羧乙基)膦及6 mol/L盐酸胍,在45℃下反应40 min即可充分还原德谷胰岛素为两条独立的肽链;还原产物经Accucore C₁₈色谱柱分离,采用静电场轨道阱高分辨串联质谱分析,当高能碰撞诱导裂解能量分别为20(A链)与25(B链)时,可获得最丰富的质谱碎片信息,可满足生物技术药物质量评价中100%的序列覆盖率的基本要求,亦可对问题样品提供更全面的序列解析。此方法未使用传统序列分析中昂贵且费时的测序级蛋白内切酶,降低了引入人为修改的风险,以更准确地获得序列信息,节约了成本,并显著提高了工作效率,为胰岛素类似物的序列分析提供了新的解决方案。