Platinum and Palladium Monolayer Electrocatalysts for Formic Acid Oxidation

Topics in Catalysis - The direct formic acid fuel cell holds great promise as a next generation portable power source. Here we report an experimental study on Pt and Pd monolayer (Pt* and Pd*) atop...     

实验用熔炉中同步进行结晶测试

在先前的文献中描述了一种空气冷却的测试管,该测试管拥有一系列的插座和插头（在结晶过程中使用的转换插座）,可以安装在实验室箱式熔炉中。该装置的用途是调节物质在坩埚槽中结晶过程的晶面和结晶速率。在本文中我们讨论一种改进型的内部冷却器——锯齿状的空气冷却管（结晶架）。这种改进型的冷却器可以简单地搭建和操作,可以延长和弯曲成为各种形状,可以用于坩埚和熔炉管中。该冷却器可以通过简单的调控对不同结晶参数和物质同步进行结晶测试,利用实验用熔炉就可以达到从一系列新型的具有层状晶体结构的化合物中得到晶体的目的。     

Stel Component Analysis: Joint Segmentation, Modeling and Recognition of Objects Classes

Models that captures the common structure of an object class have appeared few years ago in the literature (Jojic and Caspi in Proceedings of IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR), pp. 212?C219, 2004; Winn and Jojic in Proceedings of International Conference on Computer Vision (ICCV), pp. 756?C763, 2005); they are often referred as ??stel models.?? Their main characteristic is to segment objects in clear, often semantic, parts as a consequence of the modeling constraint which forces the regions belonging to a single segment to have a tight distribution over local measurements, such as color or texture. This self-similarity within a region in a single image is typical of many meaningful image parts, even when across different images of similar objects, the corresponding parts may not have similar local measurements. Moreover, the segmentation itself is expected to be consistent within a class, although still flexible. These models have been applied mostly to segmentation scenarios. In this paper, we extent those ideas (1) proposing to capture correlations that exist in structural elements of an image class due to global effects, (2) exploiting the segmentations to capture feature co-occurrences and (3) allowing the use of multiple, eventually sparse, observation of different nature. In this way we obtain richer models more suitable to recognition tasks. We accomplish these requirements using a novel approach we dubbed stel component analysis. Experimental results show the flexibility of the model as it can deal successfully with image/video segmentation and object recognition where, in particular, it can be used as an alternative of, or in conjunction with, bag-of-features and related classifiers, where stel inference provides a meaningful spatial partition of features.     

Electrically polarized ion-exchange beds in ion chromatography: eluent generation and recycling

This paper describes how electrically polarized ion-exchange beds pumped with water can produce electrolyte of steady and controllable concentration. Such devices make it possible to use water as the pumped phase in ion chromatography (IC), thus avoiding off-line eluent preparation. Control of the electrical current flowing through the devices allows precise control of the concentration of eluent that they deliver. This provides a new way of performing gradient and isocratic elutions. Using water as the carrier and two small beds of resin, one as a generator the other as a suppressor, and periodically reversing their roles through automatically switched valves, we have developed a form of continuous IC that involves little intervention by the user. The paper presents the principles of the new method and examples of its use in anion analysis.     

On-capillary ion-exchange preconcentration of inorganic anions in open-tubular capillary electrochromatogrpahy with elution using transient-isotachophoretic gradient. 2. Characterization of the isotachophoretic gradient

Diffuse transient-isotachophoretic boundaries can be used as an elution gradient of increasing eluotropic strength to elute inorganic anions that have been preconcentrated on an open-tubular ion-exchange stationary phase prior to electrophoretic separation. The generation and characteristics of these gradients for elution after preconcentration have been investigated. The gradients are generated by placing a low-mobility, weak ion-exchange competing anion in the capillary (weak electrolyte, WE), and a high-mobility, strong ion-exchange competing anion in the electrolyte vials (strong electrolyte, SE). Application of voltage establishes a diffuse boundary with the composition changing from the weak anion to the strong anion. Comparison of elution gradients generated with different electrolyte systems was accomplished by comparing the eluotropic strength (a function of eluent concentration, ion-exchange selectivity coefficient, and charge) and the shape of the profile as it changes from WE to SE. The ion-exchange selectivity coefficient of the SE competing anion is important in establishing a sharp change in elution strength. A large difference in mobility between the WE and SE competing anions gives an SE with a higher final eluotropic strength, but the slope of the gradient is shallower. This results in a reduction in the efficiency of analyte focusing. To ensure maximum focusing efficiency, the WE and SE electrolytes should be selected such that the SE has the highest possible eluotropic strength for a given concentration of WE. The SE competing anion should also have a sufficiently low electrophoretic mobility to ensure focusing for the maximum number of analytes, and the mobility difference between the WE and SE competing anions should be as small as possible.     

Structural and electrical properties of sintered zinc-titanate ceramics

The aim of this work was an investigation of structural and electrical properties of sintered zinc-titanate ceramics obtained by mechanical activation. Mixtures of ZnO and TiO₂ were mechanically activated in a planetary ball mill up to 90 min and sintered isothermally in air for 120 min at 1100 °C. The phase composition in the ZnO–TiO₂ system after milling and sintering was analyzed using the XRD method. Microstructure analyses were performed using SEM. The results of electric resistivity, capacitance and loss tangent of the sintered samples were obtained. The existence of zinc-titanate as a dielectric was proved (?_r = 12.5, Q = 386.1, tgδ = 0.0026, ρ = 1.02 Ωm).