Monitoring the Dynamic Process of Formation of Plasmonic Molecular Junctions during Single Nanoparticle Collisions

The capability to study the dynamic formation of plasmonic molecular junction is of fundamental importance, and it will provide new insights into molecular electronics/plasmonics, single‐entity electrochemistry, and nanooptoelectronics. Here, a facile method to form plasmonic molecular junctions is reported by utilizing single gold nanoparticle (NP) collision events at a highly curved gold nanoelectrode modified with a self‐assembled monolayer. By using time‐resolved electrochemical current measurement and surface‐enhanced Raman scattering spectroscopy, the current changes and the evolution of interfacial chemical bonding are successfully observed in the newly formed molecular tunnel junctions during and after the gold NP “hit‐n‐stay” and “hit‐n‐run” collision events. The results lead to an in‐depth understanding of the single NP motion and the associated molecular level changes during the formation of the plasmonic molecular junctions in a single NP collision event. This method also provides a new platform to study molecular changes at the single molecule level during electron transport in a dynamic molecular tunnel junction.     

智能耳诊机的软、硬件设计

本文从实际应用出发,详尽论述了“智能耳诊机”软、硬件设计的方法。对从事单片机开发应用的工程技术人员有较高的参考价值。     

Growth technique for producing high quality superconducting YBa2Cu3O7-δ single crystals

High quality single crystals of YBa₂Cu₃O_7- (YBCO) have been grown in yttria-stabilized zirconia crucibles by using a flux method. This method yields crystals with area 3 to 4 times larger than a previous method, and 3 to 5 times more crystals. Several crystals as large as 3×4mm² in thea-b plane are routinely obtained from each crucible. The samples typically range from 10 to 60 m thick. The superconductivity transition temperatureT _c of the crystals, measured by magnetic susceptibility, falls in the range 92.5 to 93 K and the smallest transition width (10 to 90%) is less than 0.25 K. Compared with the previous method, the surface is generally smoother, with less flux, and larger untwinned regions of 1 x 1 mm² are usually found.     

A comparative study of two techniques for improving power‐handling capability of CMOS T/R switches

This article proposes an asymmetric topology for transmit/receive (T/R) switches and more importantly presents a comparative study of both LC‐tuned and resistive body‐floating techniques for improving the power‐handling capability of the T/R switches in the same 0.18‐μm triple‐well CMOS. It is shown from simulations and measurements that the switches adopting either technique achieve comparable performances. For instance, the switch employing the LC‐tuned body‐floating technique exhibits insertion loss of 1.5 dB, isolation of 23.5 dB, and power‐handling capability of 22.5 dBm at 5.2 GHz, whereas the switch using the resistive body‐floating technique exhibits insertion loss of 1.3 dB, isolation of 24 dB, and power‐handling capability of 22.2 dBm, respectively. Therefore, one can conclude that the asymmetric topology with the resistive body‐floating technique is more suitable for designing T/R switches for wireless local area network applications as it consumes smaller silicon area. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

基于感应无线的高分辨率位置检测系统研究

为了提高移动机车位置检测精度,提出了一种感应无线位置的检测方法.该方法采用一条独特的编码电缆,利用电磁感应原理,建立了发送线圈与编码电缆之间的信息传输系统,并通过检测感应电动势的相位和幅度,得到移动机车的位置.分析了感应无线检测的原理和方法,推导出了位置检测公式,并进行相关试验.试验结果表明,感应无线位置检测分辨率为2mm,检测精度达到了国际先进水平,可广泛应用于移动机车自动定位中.