Moving beyond molecules: patterning solid-state features via dip-pen nanolithography with sol-based inks

Herein, we described a new dip-pen nanolithography (DPN)-based method for the direct patterning of organic/inorganic composite nanostructures on silicon and oxidized silicon substrates. The approach works by the hydrolysis of metal precursors in the meniscus between an AFM tip and a surface according to the reaction 2MCln + nH2O --> M2On + 2nHCl; M = Al, Si, and Sn. The inks are hybrid composites of inorganic salts with amphiphilic block copolymer surfactants. Three proof-of-concept systems involving Al2O3, SiO2, and SnO2 nanostructures on silicon and silicon oxide surfaces have been studied. Arrays of dots and lines can be written easily with control over feature size and shape on the sub-200 nm level. The structures have been characterized by atomic force microscopy, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray analysis. This work is important because it opens up the opportunity for using DPN to deposit solid-state materials rather than simple organic molecules onto surfaces with the resolution of an AFM without the need for a driving force other than chemisorption (e.g., applied fields).     

Hybrid organic-inorganic, rod-shaped nanoresistors and diodes

The electrical properties of template-synthesized three- and four-component rodlike nanostructures consisting of metal and conducting polymer domains have been studied. These structures behave like nanometer-scale resistors and diodes, depending upon their compositions and spatial distribution of the different compositional blocks. In the two-component systems, the conducting polymer block dictates the electrical properties of the nanostructure, and the metal blocks act as leads to facilitate the connection with microscopic circuits. In the three-component systems, the metal blocks provide an additional design flexibility, allowing one to prepare Schottky junctions.     

Electron transfer at self-assembled monolayers measured by scanning electrochemical microscopy

New approaches have been developed for measuring the rates of electron transfer (ET) across self-assembled molecular monolayers by scanning electrochemical microscopy (SECM). The developed models can be used to independently measure the rates of ET mediated by monolayer-attached redox moieties and direct ET through the film as well as the rate of a bimolecular ET reaction between the attached and dissolved redox species. By using a high concentration of redox mediator in solution, very fast heterogeneous (10(8) s(-1)) and bimolecular (10(11) mol(-1) cm(3) s(-1)) ET rate constants can be measured. The ET rate constants measured for ferrocene/alkanethiol on gold were in agreement with previously published data. The rates of bimolecular heterogeneous electron transfer between the monolayer-bound ferrocene and water-soluble redox species were measured. SECM was also used to measure the rate of ET through nonelectroactive alkanethiol molecules between substrate gold electrodes and a redox probe (Ru(NH(3))(6)(3+)) freely diffusing in the solution, yielding a tunneling decay constant, beta, of 1.0 per methylene group.     

Raman dye-labeled nanoparticle probes for proteins

In this paper, we demonstrate how one can chemically design Raman dye-functionalized nanoparticle probes with specific protein-binding affinities and use these probes, coupled with surface-enhanced Raman scattering (SERS) spectroscopy, to perform multiplexed screening of protein-small molecule interactions and protein-protein interactions in a protein microarray format.     

YBa2Cu3Ox超导体的光谱研究

能带是决定固体特性的头等重要的因素。我们用光谱方法对单相YBa₂Cu₂O_x高T。超导体进行了研究,测量了样品的反射-吸收谱、Raman光谱和荧光光谱.其350和500nm吸收带以及390nm,560nm荧光峰来自晶格中Cu⁺发光中心,是跃迁过程¹A_1g(3d¹⁰)-¹E_g和~3E_g(3d⁹4s¹)。其720nm和860nm荧光峰来自Cu²⁺发光中心,是由于自由离子光谱项²D在八面体晶场、正交晶系晶场中分裂为5个能级之间的跃迁。此外,还有一些光谱可能来自晶格中Cu³⁺发光中心,其481cm^-1和551cm^-1声子对说明了312cm^-1处声子对与电子系统是强耦合。     

相对论性核与乳胶(Ag)碰撞中灰粒子的系统研究 *

用描写相对论性核 核碰撞的LUCIAE模型和相应的事件产生器系统地研究了 1 4.6 ,6 0和 2 0 0AGeV的O核、2 0 0AGeV的Si和S核以及 1 1 .6AGeV的Au核与乳胶 (Ag)碰撞中灰粒子产生的平均多重数、多重数分布以及角分布 3个物理量同入射能量、射弹质量及碰撞中心度间的关系 ,还研究了再散射在灰粒子产生机制中的作用 .LUCIAE的这些研究结果与相应的EMU0 1乳胶实验结果都相一致 .     

Terthienyl and poly-terthienyl ligands as redox-switchable hemilabile ligands for oxidation-state-dependent molecular uptake and release.

Mononuclear, dinuclear, and polymeric Ru(II) complexes formed from terthienylalkylphosphino redox-switchable hemilabile ligands demonstrate that this class of ligand provides electrochemical control over the electronic properties, coordination environments, and reactivities of bound transition metals. Specifically, [CpRuCO(kappa(2)-3'-(2-diphenylphosphinoethyl)-5,5' '-dimethyl-2,2':5',2' '-terthiophene)][B(C(6)H(3)-3,5-(CF(3))(2))(4)] (4a) exhibits a 3 orders of magnitude increase in binding affinity for acetonitrile upon terthienyl-based oxidation. FT-IR spectroelectrochemical experiments on 4a indicate that terthienyl-based oxidation removes electron density from the metal center, equivalent to approximately 11-17% of the electronic change that occurs upon direct oxidation of Ru(II) to Ru(III) in analogous complexes. The spectroelectrochemical responses of 4a were compared to those of dimeric and polymeric analogues of 4a. The spectroelectrochemistry of the dimer is consistent with two sequential, one-electron ligand-based oxidations, compared to only one in 4a. In contrast, the polymer exhibits spectroelectrochemical behavior similar to that of 4a. The polymer spectroelectrochemistry shows changes in the metal center electronic properties between two different states, reflective of two discrete oxidation states of the polymeric ligand backbone. We propose that the polymer backbone does not allow one to vary the electronic properties of the metal center through a continuous range of oxidation states due to charge localization within the metalated films. In an effort to explore the molecular uptake and release properties of 4a and its polymer analogue as a function of ligand oxidation state, the oxidation-state-dependent coordination chemistries of 4a and 4a(+)() with a variety of substrates were examined.     

涡旋成对分布和对二元速度关联函数的影响

本文考虑了涡旋之间相互作用的影响,假定均匀各向同性湍流场是由涡旋对在整个空间等几率分布而成,这样计算出的二元速度关联函数f(γ/λ)在远处略有提高,这个结果是与Bennett和Corrsin的实验结果和其他实验结果相合的。