Carbon supports for the catalytic dehydrogenation of liquid organic hydrides as hydrogen storage and delivery system

The use of liquid organic hydrides as hydrogen carriers is a promising storage and delivery system due to the advantages of using liquid-based infrastructures and its economic feasibility compared to other conventional systems. The reversible dehydrogenation/hydrogenation of liquid organic hydrides is a key point for the development of highly performance reactors. In this study different carbon materials have been investigated as platinum supports, including carbon nanofibers, carbon black, carbon xerogel, activated carbon and ordered mesoporous carbon. To individuate the effect of the carbon support on the catalytic activity, platinum particles were synthesized by a microemulsion procedure. The analysis of the hydrogen evolution curves indicate that the support BET surface area plays a very important role on the initial catalytic activity, obtaining a maximum rate of 220 mmol g_Pt⁻¹ min⁻¹ when using an ordered mesoporous carbon with a surface area of 930 m² g⁻¹. Nevertheless, the analysis of catalytic activity at prolonged duration indicates a better behavior toward deactivation for supports characterized by wide pores and low graphitization degree like carbon black or carbon xerogel, despite their lower initial dehydrogenation rate (100–140 mmol g_Pt⁻¹ min⁻¹). The ultimate use in the dehydrogenation reactor as well as the operation conditions will define the best catalyst structure from the point of view of the carbon support.     

Understanding focused ion beam guided anodic alumina nanopore development

Focused ion beam (FIB) patterning in combination with anodization has shown great promise in creating unique pore patterns. This work is aimed to understand the effect of the FIB patterned sites in guiding anodized pore development. Highly ordered porous anodic alumina has been created with the guidance of FIB created patterns on electropolished aluminum followed by oxalic acid anodization. Shallow concaves created by the FIB with only 1.5 nm depth can effectively guide the growth of ordered nanopore patterns. With the guidance of the FIB pattern, the anodization rate is much faster and the nanopore growth direction bends at the boundary of the FIB patterned and un-patterned regions. FIB patterning also enlarges the anodization window; ordered nanopore arrays with 150 nm interpore distances can be produced under an applied potential from 50 V to 80 V. The fundamental understanding of these unique processes is discussed.     

Investment preferences for wood-based energy initiatives in the US

The forest sector is poised to become a major supplier of wood-based energy in the US. Prospects for growth in energy demand and higher prices can create opportunities for private investments in renewable energy industries. A conjoint analysis examined individuals’ willingness to invest in wood-based energies following a random utility model. The study design included three investment attributes: annual returns on investment, type of investment, and location of investment. Three ordinal models that also included demographic and attitudinal characteristics indicate that wood-based energy is less preferred among potential investors compared to the stock market and solar/wind renewable energy investments. Expected returns and location of energy investments within the US are also major drivers of investment preferences. Favorable attitudes towards forestry and wood-based energy could enhance prospects for a greater number of potential investors.     

First-principles study of nickel-silicides ordered phases

We present a study of nickel-silicides ordered alloys by means of first-principles calculations. Emphasis was put on the phases (low and high temperatures) identified in the binary phase diagram, namely: Ni₃Si-β₁, -β₂, and -β₃, Ni₃₁Si₁₂-γ, Ni₂Si-δ, -θ, Ni₃Si₂-?, NiSi-MnP and NiSi₂-α. In addition, some common structures are computed for information: L1₂, D0₃ and D0₂₂. The simulations reproduce with a high accuracy lattice parameters and formation energies of main experimental structures, except for β₂ and β₃. Our results clarify the crystallographic nature of the γ structure, and the comparison of experimental Raman spectra and vibrational calculations will help experimentalists to identify without ambiguity NiSi₃ structures.     

Fabrication of highly ordered and vertically oriented TiO2 nanotube arrays for ordered heterojunction polymer/inorganic hybrid solar cell

Highly ordered and vertically oriented TiO₂ nanotube arrays with a length of 250 nm and a diameter of 70 nm were prepared by atomic layer deposition (ALD) coupled with anodic aluminum oxide (AAO) template. An ordered heterojunction (OHJ) polymer/inorganic hybrid solar cell was fabricated by successful infiltration of P3HT into the nanotube arrays. Structural features of the nanotube arrays enabling the interdigitated structure of the OHJ were discussed and the performance of the solar cell was characterized to be the power conversion efficiency of 0.50%.     

GENERALIZED THRESHOLD DECOMPOSITION

This paper develops a powerful technique called threshold decomposition which is introduced for the analysis and implementation of median filter. This technique called generalized decomposition(GTD) is better than the original method in the theoretical analysis and VLSI realization.     

Single-crystalline Ag2S hollow nanohexagons and their assembly into ordered arrays

Single-crystalline Ag₂S hollow nanohexagons with better quality and narrower size distribution were successfully synthesized in aqueous solution at low temperature. The obtained products were characterized by using X-ray power diffractometer (XRD), field emission scanning electronic microscopy (FE-SEM) and transmission electronic microscopy (TEM). The possible mechanism for the formation of hollow nanohexagons was discussed. The hollow nanohexagons could “bottom-up” assemble into large-scale high-quality ordered arrays with the ordering over a distance up to several micrometers and even larger because of their high uniformity and van der Waals interactions. Due to anisotropic behaviour, large surface area and low material density, single-crystalline Ag₂S hollow nanohexagons and their ordered arrays were expected to exhibit superior properties and to have potential applications in fabricating new useful nanodevices in the future.     

一种新的基于有序统计和剔除平均的最大选择恒虚警检测器

本文基于有序统计（ＯＳ）和剔除平均（ＴＭ）提出了一种新的恒虚警检测器（ＯＳＴＭＧＯ）它的前尚滑窗和后尚滑窗分别采用ＯＳ和ＴＭ来产生局部估计，再选择两者之中的最大值用为杂波功率水平的估计，并应用于文献（４）提出自己筛选技术，在ＳｗｅｒｌｉｎｇⅡ型目标假设下，本文推导出了它的Ｐｆａ，Ｐｄ和度量，ＡＤＴ的解析表达式，并与其它方案进行了比较，分析结果表明它的均匀背景及多目标和杂波边缘引起的非均匀背景中，均     

Research on thin film lubrication: state of the art

Thin film lubrication (TFL) has been well studied as a new lubrication regime since 1990s. TFL is a transition lubrication regime between elastohydrodynamic lubrication (EHL) and boundary lubrication (BL), which has specific lubrication features. Present paper summarizes the advancements of researches on TFL, which involves the origin of the TFL concept, advancement of measuring techniques, TFL film-forming features, investigation on its mechanism, and computation theories.     

Cathode catalyst layer using supported Pt catalyst on ordered mesoporous carbon for direct methanol fuel cell

The development of a cathode catalyst layer based on a supported Pt catalyst using an ordered mesoporous carbon (OMC) for direct methanol fuel cell is reported. An OMC with a mesopore structure between hexagonally arranged carbon nanorods is prepared using a template method. Platinum nanoparticles are supported on the OMC (Pt/OMC) with high metal loading of 60 wt.%. Compositional and morphological variations are made by varying the ionomer content and by compressing the catalyst layer to detect a parameter that determines the power performance. Increase in power density with decrease in the volume fraction of ionomer in the agglomerate comprising the Pt/OMC and the ionomer indicates that mass transport through the ionomer phase governs the kinetics of oxygen reduction. Impedance spectroscopic analysis suggests that a significant mass-transport limitation occurs at high ionomer content and in the compressed cathode. The power density of the optimum cathode layer, which employs a Pt/OMC catalyst with a Pt loading of 2 mg cm⁻², is greater than that of a catalyst layer with 6 mg cm⁻² Pt-black catalyst at a voltage higher than 0.4 V. This would lead to a significant reduction in the cost of the membrane electrode assembly.