Graphene resistive random memory — the promising memory device in next generation

Graphene-based resistive random access memory(GRRAM) has grasped researchers' attention due to its merits compared with ordinary RRAM. In this paper, we briefly review different types of GRRAMs. These GRRAMs can be divided into two categories: graphene RRAM and graphene oxide(GO)/reduced graphene oxide(r GO) RRAM. Using graphene as the electrode, GRRAM can own many good characteristics, such as low power consumption, higher density, transparency,SET voltage modulation, high uniformity, and so on. Graphene flakes sandwiched between two dielectric layers can lower the SET voltage and achieve multilevel switching. Moreover, the GRRAM with r GO and GO as the dielectric or electrode can be simply fabricated. Flexible and high performance RRAM and GO film can be modified by adding other materials layer or making a composite with polymer, nanoparticle, and 2D materials to further improve the performance. Above all,GRRAM shows huge potential to become the next generation memory.     

石墨烯研究进展

石墨烯是目前发现的唯一存在的二维自由态原子晶体,它是构筑零维富勒烯、一维碳纳米管、三维体相石墨等sp²杂化碳的基本结构单元,具有很多奇异的电子及机械性能。因而吸引了化学、材料等其它他领域科学家的高度关注。本文介绍了近几年石墨烯的研究进展,包括石墨烯的合成、去氧化、化学修饰及应用前景等方面的内容。     

矿井防尘供水管网系统的GO法可靠性分析

为保障煤矿生产的安全运行,采用GO法分析矿井防尘供水管网的可靠性.以双鸭山某矿防尘系统为例,根据其工作原理和结构建立GO图,利用概率公式算法对防尘供水管网系统进行定量和定性的GO运算,获得了系统的状态概率和最小割集.结果表明,比故障树法对同一系统的分析结果更精确.GO方法能够反映系统原貌,非常适合模拟有序列过程的状态系统.对于较复杂的系统,GO法则显得比较简单,优势更加明显.     

YAG激光器系统可靠性分析中GO法的应用

GO法是一种以成功为导向的系统概率分析技术,已应用于可修系统的可靠性分析。YAG激光器振荡阈值较低、能量转换效率较高,在室温下能以连续或脉冲方式工作,具有广泛的应用领域。该文应用GO法分析YAG激光器系统的可靠性,得到系统平均无故障工作时间等重要可靠性指标。对各部件的故障率和维修率的重要度进行了分析,指出闪光灯是影响YAG激光器系统可靠性的最重要部件,讨论了改善YAG激光器系统可靠性的措施。说明GO法适用于YAG激光器系统的可靠性分析,可进一步推广并应用于其他激光器系统。     

宽带调频连续波近程多站雷达系统对细柱状目标定位研究

首次将宽带调频连续波发射波形引入近程多站雷达系统,利用宽带调频连续波雷达信号的高距离分辨率分析了近程细柱状目标几何中心定位的性能,提出了利用回波频谱估计细柱状目标长度的方法并给出了计算表达式,对系统性能进行了计算机仿真,所得结果对工程实践有一定的指导意义     

基于诱导多潜能干细胞的Alport综合征蛋白质组学的生物信息

目的:探讨Alport综合征(AS)差异性表达蛋白质主要参与的GO富集分析和KEGG通路,为AS的进一步机制研究奠定基础.方法:10例AS患者与10例健康对照者(NC)作为实验对象.分别收集实验参与者尿液200 m L,并从尿液中分离尿肾脏管细胞,将尿肾脏管细胞诱导分化成多潜能干细胞(i PSCs),运用i TRAQ技术找出2组之间差异性表达蛋白质,对其进行生物信息学分析.结果:在2组样本中发现35种蛋白质具有差异性表达,包括18种上调与17种下调.差异性表达蛋白质GO富集主要聚集在细胞分子、细胞组成与细胞生物学过程.嘌呤代谢通路与丝裂原激活的蛋白激酶是主要的KEGG信号传导通路.结论:差异性表达蛋白质的生物信息学有助于AS发病机制研究,可作为机制研究参考和补充.     

大尺寸石墨烯量子点组装体的制备及电化学发光性能

对氧化石墨烯纳米材料进行HNO₃氧化处理, 制备了水溶性好且具有强电化学发光(ECL)活性的大尺寸石墨烯量子点组装体(Large-sized graphene quantum dot assemblies, LSGQD-NAs). 利用透射电子显微镜(TEM)、 原子力显微镜(AFM)、 傅里叶变换红外光谱(FTIR)和拉曼光谱(Raman)等方法对其进行了表征, 结果表明, 石墨烯量子点组装体的平均高度为20 nm, 且富含大量的羟基和羧基. 电化学测试结果显示, 在共反应物K₂S₂O₈存在下, LSGQD-NAs在阴极产生很强的ECL(峰值约在685 nm); 并推测了其ECL反应机理, 发现LSGQD-NAs容易通过中心未氧化的石墨烯π-π作用于GC电极表面进行组装修饰. 本研究为基于石墨烯量子点ECL传感器的研究提供了新方法.     

Conjugate polymer-based membranes for gas separation applications: current status and future prospects

Conjugate polymers provide the possibility of exploiting both the chemical and physical attributes of the polymers for membrane-based gas separation. The presence of delocalized π electrons provides high chain stiffness with low packing density, thus making the membrane a rigid structure that favors facilitated transport. Historically, the polymeric membranes were constrained by the tradeoff relationship between gas permeability and gas selectivity. So, different methods were investigated to prepare the membranes that can overcome the limitation. In recent years, electroconductive polymeric membranes have gained attention with their enhanced transportation properties combining the separation behavior depending on both molecular size discrimination as well as the facilitated transport. They offer better selectivity toward polar gases such as CO₂ because of the increased solubility. This review is aimed to provide a literature survey on gas separation using conjugate polymers such as polyaniline, polypyrrole, and some derivatives of polythiophenes. It contains various methods used by different researchers to enhance the gas separation properties of the membranes with improved mechanical and thermal stability such as changing the morphology and membrane preparation methods. In addition, it provides the pros and cons of various factors affecting the conjugate polymer membrane performance. The major challenges and future work that can be done in improving the transportation properties through the membrane to achieve viable membranes are also discussed so that they can be used for commercial and practical applications in the future.     

氧化石墨烯色谱固定相的制备及其在食品中三聚氰胺分析中的应用

以N,N-二环己基碳二亚胺为偶联剂,利用氧化石墨烯表面的羧基与氨基化硅球表面的氨基反应合成了一种氧化石墨烯键合硅球色谱固定相,通过扫描电镜和拉曼光谱对其进行表征,并考察了极性小分子在柱上的色谱行为。与氨基化硅球固定相相比,在相同的色谱条件下,三聚氰胺、双氰胺等氨基化合物的保留因子明显提高,且该固定相在亲水模式下对氨基化合物具有良好的保留性能,将其作为分析柱用于鸡蛋和牛奶中三聚氰胺的分析。该方法在0.2~50μg/m L范围内线性良好,相关系数(r)为0.999 9,定量下限为0.87mg/kg。在1,2,10 mg/kg加标水平下的回收率为84.7%~93.9%,相对标准偏差为4.1%~6.3%。     

Paper-based diagnostic platforms and devices

Paper-based analytical devices have become lately “must have” components in equipment and instrumental designed for point-of-care applications, especially when they are used in tandem with microfluidic platforms. Nowadays, paper-based electrochemical devices (PEDs) represent the first choice in the development of lab-on-a-chip biosensors because of their benefits in biomedical diagnosis in terms of simplicity, affordability, portability, and disposability. Moreover, cellulose is a biodegradable and biocompatible substrate, ideal for building disposable devices for use in remote locations or low-resource settings. Despite their low costs and simplicity, PEDs must face a tough challenge—meeting the affordable, sensitive, specific, user-friendly, rapid and robust, equipment-free, and deliverable to end users criteria. The latest achievements in microfluidic PEDs for clinical diagnosis will be critically discussed, putting emphasis on innovative assay formats and methods for surface modification.