纳米阵列电极研究

纳米阵列电极作为一种人工组装的纳米结构体系,具有高传质速率、低双电层充电电流、小时间常数、小IR降及高信噪比、可操作性强和测量灵敏度高等优势,因而在电化学理论研究、生物传感器、电催化材料和高能化学电源电极材料等方面等具有广阔的应用前景。迄今为止,人们采用多种材料设计制备出包括圆盘状、圆柱形、球形、圆锥形、叉指状和井状等各种形状的纳米阵列电极。其制作方法主要包括模板法、刻蚀法和自组装法等,电极的表征主要采用电子显微镜技术和电化学方法。本文结合我们的工作和国内外文献,就纳米阵列电极制作方法、表征和应用等方面进行了评述,并对目前纳米阵列电极研究中存在的问题及发展前景进行了探讨和展望。     

Quantitative Bestimmungen

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Luminescent core-shell photonic crystals from poly(phenylene ethynylene) coated silica spheres

We describe the preparation and characterization of a photonic crystal filled with a luminescent conjugated polyelectrolyte, sulfonated poly(phenylene ethynylene). The conjugated polymer was coated onto the nanospheres by the layer-by-layer method and assembled directly into a fluorescent opal structure avoiding the defects associated with post-filling schemes. These structures exhibit strong angle-dependent luminescent properties. By using multiple layers, we further demonstrate control over the emissive bands of the opal.     

Chemical synthesis of the first lignans to be found in humans and animals

$\text{Trans}$-2,3-$\text{bis}$-(3′-hydroxybenzyl)-butyrolactone (1) and 2,3-$\text{bis}$-(3′-hydroxybenzyl)-butane-1,4-diol (2), recently identified in urine, have been synthesised in racemic form.     

Evidence of order-parameter symmetry and of a normal metallic state in electron-irradiated YBa<Subscript>2</Subscript>Cu<Subscript>3</Subscript>O<Subscript>7−δ</Subscript> (YBCO)

A key difference between a d-wave superconductor and an anisotropic s-wave one is the expected effect of nonmagnetic point defects on T_c. For the former, T_c becomes zero, whereas for the latter, T_c reaches a nonzero constant value beyond a critical concentration of impurities. We report that T_c of single-crystal YBCO becomes less than 12K, our lowest temperature, when 4.1% of the planar oxygens O(2,3) are displaced by 400keV electrons, incident along the c-axis. Our data therefore suggest that YBCO is a d-wave superconductor. We also report a disorder-induced transition from superconductor-to-normal metal.     

O.R. in the Company Car Fleet: When Simple is Efficient

The management of a large fleet of company vehicles represents a significant administrative activity, particularly when the company is a motor vehicle manufacturer and the fleet consists of its own products. The approach taken by the Operational Research Group was to cross departmental boundaries to smooth vehicle ordering, reduce inventories of vehicles awaiting delivery and optimize resale values. The method steers between two potential pitfalls: that of ‘optimizing’ one affected department to the detriment of others, and that of developing sophisticated scheduling and forecasting algorithms which the users would not understand and therefore not trust.