Scalable bottom‐up assembly of suspended carbon nanotube and graphene devices by dielectrophoresis

Bottom‐up assembly by dielectrophoresis (DEP) has emerged in recent years as a viable alternative to conventional top–down fabrication of electronic devices from nanomaterials, particularly carbon nanotubes and graphene. Here, we demonstrate how this technique can be extended to fabricate devices containing carbon nanotubes and graphene suspended between two electrodes over a back‐gate electrode. The suspended device geometry is critical for the development of nano‐electromechanical devices and to extract maximum performance out of electronic and optoelectronic devices. This technique allows for parallel assembly of devices over large scale. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Microwave-assisted digestion with a single reaction chamber for mineral fertilizer analysis by inductively coupled plasma optical emission spectrometry

A systematic approach is proposed to evaluate microwave-assisted digestion in a single reaction chamber for the simultaneous determination of elements in the mineral fertilizer and raw material by inductively coupled plasma optical emission spectrometry. A reference material was digested using 12 acid mixtures containing nitric, hydrochloric, orthophosphoric, hydrofluoric or boric acid. Principal components analysis was applied for data treatment. Three digestion procedures based on diluted acids exhibited the most accurate results, with relative errors for reference values ranging from ?15% to +?9%. Limits of quantification were in the range of 0.2?mg cadmium kg^?1 up to 1000?mg aluminum kg^?1.     

电感耦合等离子体发射光谱法测定记号笔笔芯和墨水中铜和铬

报道了使用ICP-AES测定记号笔芯和墨水中的铜和铬的方法。 主要关注了不同的样品前处理方法的研究。 结果表明: 对标记用的油性记号笔笔芯和含有高分子树脂的墨水, 采用550 ℃灰化, 混合酸(V_HNO3∶V_HClO4=3∶1)溶解的方法处理样品, 是该类样品比较好的处理方法; 而对不含有高分子树脂的墨水, 采用直接用混合酸(V_HNO3∶V_HClO4=3∶1)的消解即可。 消解后的样品经稀酸酸化后, 采用ICP-AES测定铜和铬, 结果准确、稳定。该方法适合记号笔或墨水中元素的测定。     

火焰原子吸收光谱法测定砂金中金,银

本文研究了用王水溶解砂金样品，在１％王水介质中，使银生成氯化银沉淀与金定量分离。滤液控制１％王水介质用以测定金。沉淀用５％热硫有脲溶解，控制为１％硫脲介质用以测定银。利用本方法测定了砂金样品中金和银得到了满意结果。金的回收率为９９．６％－１００．８％，银的回收率为９７．２－９９．２％。     

TE011腔使用扁平样品管提高水溶液样品ESR波谱灵敏度的研究

实验表明,在TE₀₁₁模式园柱形腔中,不但可以使用扁平样品管测量水溶液样品的ESR波谱,而且获得好的腔品质因子Q和高品质的ESR信号。所观察到的信号高度,是使用最佳尺寸毛细管样品时最大信号高度的3.2倍;又是在具有波导尺寸的TE₁₀₂腔中使用扁平样品管时所获得信号高度的3倍。本文对此作了定性的理论分析。     

光突发交换网络中最长队列优先调度组装机制

提出了光突发交换网络中的最长队列优先调度（LQF-SA）机制,将边缘节点的突发组装和突发调度两种技术紧密结合在一起.在现实网络中,业务通常是非均匀分布的,即在某些源宿对之间存在更大的业务流量.仿真结果表明,LQF-SA机制可以很好地完成非均匀分布业务流的组装.即使在均匀分布业务流输入下,LQF-SA机制在突发大小分布、组装效率和突发丢失率等方面也优于已提出的轮询调度组装（RR-SA）机制.     

掠过双板流动引起的旋涡脱落特性数值模拟

板状燃料组件在先进核反应堆中得到重要应用.流体以一定的流速轴掠板状组件时会导致板后产生旋涡脱落现象.旋涡脱落有可能引发板状燃料组件的流致振动.使用BELIEF程序,通过改变方柱间距模拟了Re=200情况下刚性矩形通道内不同节距条件下双平行方柱的旋涡脱落现象,得出了双柱间节距对双平行方柱旋涡脱落特性的影响,并进一步对双平...     

基于贝叶斯序贯方法的微波效应实验设计

提出了一种基于贝叶斯验后概率的序贯检验方法,建立了检验的判别准则,给出了判别准则临界值的计算方法。在给定截尾实验次数的条件下,提出了一种截尾方案,建立了截尾判断方法。将其用于解决验证效应物在微波作用下失效概率达到给定水平的微波效应实验设计问题,给出了相应的实验方案和所需样本量的估计。最后,通过实例对上述方法的应用过程进行了说明,并和现有方法进行了分析比较。     

15N/14N Analysis of Amino Acids with GC-C-IRMS - Methodical Investigations and Ecotoxicological Applications

Abstract

In order to perform the ¹⁵N/¹⁴N analysis of amino acids using a gas chromatograph and isotope ratio mass spectrometer linked up via a combustion interface (GC-C-IRMS), the amino acids must be derivatized. Tert-butyldimethylsilylation is examined using various techniques (direct conversion to nitrogen gas, ConFlo-IRMS [1], GC-C-IRMS [2]) and subsequently applied to isotopic characterization of amino acids from wheat protein hydrolyzate obtained from plants exposed to ozone. The method provides a reliable tool for studying ecotoxicological effects on plants at a molecular level in addition to the investigation of the natural variations of different N fractions.