扫描电化学显微镜及其最新进展

对扫描电化学显微镜技术的基本原理,仪器设备,最新的研究进展和发展展望进行了评述。     

Magnetic-field-induced electric polarization in multiferroic nanostructures

Magnetic-field-induced electric polarization in nanostructured multiferroic composite films was studied by using the Green's function approach. The calculations showed that large magnetic-field-induced polarization could be produced in multiferroic nanostructures due to enhanced elastic coupling interaction. Especially, the 1-3 type films with ferromagnetic nanopillars embedded in a ferroelectric matrix exhibited large magnetic-field-induced polarization responses, while the 2-2 type films with ferroelectric and ferromagnetic nanolaminates showed much weaker magnetoelectric coupling and lower magnetic induced polarization due to large in-plane constraint effect, which was in agreement with the recent observations.     

10cm双潘宁型离子源的整治与调试

双潘宁放电型离子源是用于受控核聚变研究装置的主要强流离子源型之一。这个由TFR装置退役、又在运输过程中严重受损的10cm双潘宁型离子源,经我们重新整治恢复之后,经调试已达到的主要结果是,引出的氢离子束的流强为10.2A,离子能量为30keV,束脉冲宽度100ms,束散角1.6°,离子源弧效率约0.65A/kW。结果表明,该源已基本达到国外同类型源在相近能量下的运行水平。     

反映工艺条件对管式反应器催化反应影响的转化率方程

根据幂指函数g(u))=ua+bu的特点,借用"虚拟反应组分"和"变动级数"的概念,提出了管式反应器系统中反应转化率与工艺条件的关系式XM=1-exp[-exp(A+B/Tr+CTr)Prnp0+np1Prτnrr0+nr1τrm∏i=1yniy0+ny1y1].为了验证该转化率方程的普适性,考察了二乙苯催化脱氢、乙苯...     

Oxidatively Induced Selective Carbon-Carbon Bond Formation From Isolated Rhodium(III) Complexes

This work focuses on oxidatively induced regioselective intramolecular C−C bond formations based on the Rh^III complexes synthesized from dirhodium(II) trifluoroacetate with 2-arylpyridines. With the selection of electron-donating groups on the arene rings of 2-arylpyridines, the unusual meta-ortho C−C bond-forming was favored, which led to the formation of meta-substituted 2-arylpyridine homocoupling dimers. On the contrary, the electron-withdrawing groups have tendency to occur conventional ortho-ortho bond-forming, resulting in the formation of new Rh^III complexes possessing the intriguing Rh^III(TFA)₃ fragment. Preliminary mechanistic experiments suggest that the sequential oxidation of Rh^III occurred in the reaction.     

Local Polynomial Fitting with Long-Memory, Short-Memory and Antipersistent Errors

Local polynomial smoothing for the trend function and its derivatives in nonparametric regression with long-memory, short-memory and antipersistent errors is considered. We show that in the case of antipersistence, the convergence rate of a nonparametric regression estimator is faster than for uncorrelated or short-range dependent errors. Moreover, it is shown that unified asymptotic formulas for the optimal bandwidth and the MSE hold for all of the three dependence structures. Also, results on estimation at the boundary are included. A bandwidth selector for nonparametric regression with different types of dependent errors is proposed. Its asymptotic property is investigated. The practical performance of the proposal is illustrated by simulated and real data examples.     

Investigation of the interactions between silver nanoparticles and Hela cells by scanning electrochemical microscopy

The interactions between Hela cells and silver nanoparticles (AgNPs) have been studied by scanning electrochemical microscopy (SECM) with both IrCl(6)(2-/3-) and Fe(CN)(6)(3-/4-) as the dual mediators. IrCl(6)(2-), which can be produced in situ and react with AgNPs, is used as the mediator between the AgNPs on the cells and the SECM tip. Another redox couple, Fe(CN)(6)(3-/4-), which has a similar hydrophilicity to IrCl(6)(2-/3-), but cannot react with AgNPs, is also employed for the contrast experiments. The cell array is cultured successfully onto a Petri dish by microcontact printing (muCP) technique, which can provide a basic platform for studying of single cells. The approach curve and line scan are the two methods of SECM employed here to study the Hela cells. The former can provide the information about the interaction between Hela cells and AgNPs whereas the later gives the cell imaging. The permeability of cell membranes and morphology are two main factors which have effects on the feedback mode signals when K(3)Fe(CN)(6) is used as the mediator. The permeability of the cell membranes can be ignored after interaction with high concentration of AgNP solution and the height of the Hela cells is slightly decreased in this process. The kinetic rate constants (k(0)) between IrCl(6)(2-) and Ag on the Hela cell can be evaluated using K(3)IrCl(6) as the mediator, and they are increased with the higher concentrations of the AgNP solutions. The k(0) is changed about 10 times from 0.43 +/- 0.04 x 10(-4) to 1.25 +/- 0.07 x 10(-4) and to 3.93 +/- 1.9 x 10(-4) cm s(-1) corresponding to 0, 1 and 5 mM of AgNO(3) solution. The experimental results demonstrate that the AgNPs can be adsorbed on the cell surface and detected by SECM. Thus, the amount of AgNPs adsorbed on cell membranes and the permeability or morphology changes can be investigated simultaneously using this approach. The dual mediator system and cell array fabricated by muCP technique can provide better reproducibility because they can simplify experiments, and provide a platform for further single cell detection.     

Incorporation of disodium alkyl polyoxyethylene ether sulfosuccinate inside styrene droplets: mechanism and its application for preparation of multihollow polymer spheres

Emulsion polymerization of styrene was carried out using two kinds of alkyl polyoxyethylene ether sulfosuccinates as surfactant: disodium cetyl polyoxyethylene (25) ether sulfosuccinate (CPS) and octyl-phenol polyoxyethylene (10) ether sulfosuccinate (OPS). In experiments, the incorporation of CPS or OPS inside styrene droplets and polystyrene particles was clearly observed. Based on this phenomenon, multihollow polymer spheres are prepared in a one-step reaction and this strongly supports the proposed incorporation mechanism. CPS is more effective than OPS during the preparation of multiporous spheres. This difference between the two surfactants mainly contributes to the difference of the length of the EO (polyoxyethylene) group, which can determine the affinity among surfactant, styrene, and water molecules.     

基于特异性蛋白Gαa的比浊法检测β-葡聚糖

通过基因重组技术,克隆表达了β-葡聚糖特异性结合美洲鲎G因子α亚基片段a(Gαa)蛋白,并建立了β-葡聚糖比浊检测方法。克隆的Gαa基因相对分子质量为40000(1251 bp),浓度为2 g/L,纯度达到98%以上。该蛋白能与βG特异性结合,紫外分光光度计在340 nm下检测的吸光度与βG含量呈正线性相关,线性范围3.125~200 mg/L,R2=0.997,检测限3.125 mg/L。结合力实验表明,该蛋白与βG具有良好的亲和性及特异性。该方法具有成本低、快速、专一性强等特点。