High-Performance Quasi-Solid-State Na-Air Battery via Gel Cathode by Confining Moisture

Rechargeable Na-air batteries are the subject of great interest because of their high theoretical specific energy density, lower cost, and lower charge potential compared with Li-air batteries. However, high purity O₂ as a working environment is required to achieve high-performance Na-air batteries, which obstructs their application as a high-energy-density battery. Although aqueous Na-air batteries can operate in ambient air, long cycle and high safety remain challenges for aqueous Na-air batteries because the aqueous electrolyte is volatile. Here, a quasi-solid-state Na-air battery is reported by utilizing a gel cathode, which is composed of single-walled carbon nanotubes and room-temperature ionic liquids, achieving high safety and long cycling life of 125 cycles (528 h) at a current density of 0.1 mA cm⁻², which is surprisingly better than that of quasi-solid-state Na O₂ batteries. In situ XRD characterizations reveal that water in ambient air is gradually deposited on the surface of the gel cathode to form a water layer, which facilitates the generation of soluble discharge product of NaOH thermodynamically with high conductivity. This work shall be critical to develop and promote the practical application of Na-air batteries, opening a new way to the design of solid-state metal-air batteries.     

Oil Microsealing: A Robust Micro‐compartmentalization Method for On‐Chip Chemical and Biological Assays

A simple and robust method to compartmentalize aqueous solutions into an array of independent microchambers is presented. The array of microchambers fabricated in poly(dimethylsiloxane) are filled with the sample solution through a microfluidic channel and then sealed with oil to isolate the microchambers from each other. A water reservoir close to the microchambers allows the maintainance and incubation of sub‐nanoliter solutions (e.g., at 37 °C) within the chambers for hours without any problem of evaporation. Once assembled, the device is self‐sustainable and can be used for different application purposes. As a demonstration, the device configuration is shown to be suitable for spatiotemporal control of the inner solution conditions by light stimulation through a photomask. This method was applied for the generation of regular EmGFP (emerald green fluorescent protein) expression arrays, selective photobleaching, photopatterning of calcium concentration, and cell culture in independent microchambers.     

Fe/N/C non-precious catalysts for PEM fuel cells: Influence of the structural parameters of pristine commercial carbon blacks on their activity for oxygen reduction

Fifteen commercial SRCC furnace carbon blacks of various grades, ranging from N1 to N9, were used as carbon supports in the preparation of Fe/N/C type electrocatalysts for the oxygen reduction reaction (ORR) in PEM fuel cell conditions. All catalysts were prepared by loading the various carbon grades with 0.2 wt.% Fe as iron acetate and heat-treating the resulting material at 950 °C in pure NH₃. This reaction provides the nitrogen content and the microporosity necessary to synthesize and host the Fe/N/C catalytic sites that perform ORR. The maximum catalytic activity (V_pr max) for each carbon grade was determined by optimizing pyrolysis time. The aim of this study is to determine which structural characteristics of the pristine carbon black are important for maximizing catalytic activity. Three structural parameters that influenced the catalytic site density on the carbon support were identified. They are: (i) the average particle diameter of the pristine carbon black, d_particle, available from BET area measurements; (ii) the amount of disordered phase which is proportional to W_D, the width at half maximum of the D peak in the Raman spectrum of the pristine carbon; and (iii) the mean size of the graphene layers characterizing the graphitic crystallites in the carbon black, L_a. The latter is available by Rietveld analysis of the XRD spectra of the pristine carbons. The best catalytic activities are obtained for the smallest d_particle, the largest W_D, and the largest L_a. Optimizing these three parameters maximizes the fraction of the pristine carbon black that becomes microporous upon reaction with NH₃ and, therefore, enables the formation of Fe/N/C catalytic sites. A FeN₂₊₂/C structure bridging two adjacent graphitic crystallites is proposed as a potential model for most of the catalytic sites present in such Fe/N/C type catalysts.     

Chemical composition and bioactive compounds of flour of orange (Citrus sinensis), tangerine (Citrus reticulata) and grapefruit (Citrus paradisi) peels cultivated in Venezuela

The purpose of this research was to evaluate the chemical composition and some bioactive compounds in the peel's flour of some of the most consumed citrus fruits cultivated in Venezuela. Chemical composition as well as some trace elements, ascorbic acid, carotenoids dietary fiber, total polyphenols and their antiradical efficiency, using the 2,2-diphenyl-1-picrylhidracyl (DPPH) were assessed in the dried peels of orange (Citrus sinensis), tangerine (Citrus reticulata) and white grapefruit (Citrus paradisi). Moisture, fat, protein and ash content for all samples showed statistical differences (p < 0.05). Tangerine's peel showed the highest magnesium and carotenoid content, while highest ascorbic acid and carotenoid content was found in the grapefruit's peel. Dietary fiber content presented significant high value in the tangerine peel. All samples presented high content of extractable polyphenols (4.33; 7.6 and 5.1 g/100g). The highest antiradical efficiency was shown by the tangerine's peel, value which correlates with the polyphenol content. These results suggest that tangerine peel should be the most suitable, to reduce risk of some diseases such as cardiovascular and some associated to lipid oxidation. Studied samples are good sources of dietary fiber and phenolic compounds, whose use could be useful in the formulation of functional foods, taking advantage of the presence of dietary fiber and antioxidant compounds in only one ingredient.     

主板行情

微星本月推出了一款集成主板，这本来没有什么好引起关注的，但是由于该主板采用创新音效解码芯片，相当于Sound Blaster Audigy SE，因此不免令人非常好奇。集成声卡对于创新公司的冲击勿庸置疑，而此番创新再次选择配合集成主板，很可能预示着未来还会有更大的动作。凭借创新的号召力，预计搭配创新声卡的主板将在市场上非常抢手。     

主板行情

Intel退出中低端芯片组市场已经是公开的秘密，然而就在人们为其接替者争论不休时，似乎Intel心中早巳饮点了合作者。一向与Intel关系紧密的SiS成内了幸运者，继Intel在官方渠道宣布推荐SiS中低端芯片组之后，近期竟然宣布免受SiS芯片组权益金。2.5美元的权益金令SiS在面对VIA等芯片组厂商时占据很大的成本优势。     

Dreams of light for the city

This article describes research that aspires to develop a tool to restore well-tempered variety, space-time continuity, identity, and self-visualization to contemporary Greek urbanscape. This tool uses color as a building facade structuring material and takes into account confusing plastic structure and the shifting nature of contemporary Greek urban populations. the research is based on existing information and on psychometric data with users. The project included six stages: a) an estimation of the deviation of the existing representational space from the desired space representation, b) a semiotic analysis of representative building facade samples into generic color forms, (c) the recording of the color preferences of selected subjects for these forms, d) a semantic coding of the subjects' reasons for these preferences, e) the establishment of a color scheme on the basis of the resulting color combinations, and f) a comparison of the color choices by the various groups of subjects for each building category. The results show that a) color is mostly affected by the sociocultural aspect of architecture, b) function is the major parameter taken into account for middle-class constructions, c) the visual differentiation resulting from the color rendering of the facade elements according to the subjects' preferences can lead to architecture and planning identification, d) spatial, functional, and sociocultural qualities can also be attributed to the city through color-conditioning, and e) above all, color can best portray the particular character of a city, what it was, is, or wants to be in the future.     

Contribution of treated wastewater to the microbiological quality of Seine River in Paris

Urban part of Seine River serving as drinking water supply in Paris can be heavily contaminated by Cryptosporidium spp. and Giardia duodenalis. In the absence of agricultural practice in this highly urbanized area, we investigated herein the contribution of treated wastewater to the microbiological quality of this river focusing on these two parasites. Other microorganisms such as faecal bacterial indicators, enteroviruses and oocysts of Toxoplasma gondii were assessed concurrently. Raw wastewaters were heavily contaminated by Cryptosporidium and Giardia (oo)cysts, whereas concentrations of both protozoa in treated wastewater were lower. Treated wastewater, flowed into Seine River, had a parasite concentration closed to the one found along the river, in particular at the entry of a drinking water plant (DWP). Even if faecal bacteria were reliable indicators of a reduction in parasite concentrations during the wastewater treatment, they were not correlated to protozoal contamination of wastewater and river water. Oocysts of T. gondii were not found in both raw and treated wastewater, or in Seine River. Parasitic contamination was shown to be constant in the Seine River up to 40 km upstream Paris. Altogether, these results strongly suggest that treated wastewater does not contribute to the main parasitic contamination of the Seine River usually observed in this urbanized area.     

Multiscale investigation of graphene layers on 6H-SiC(000-1)

In this article, a multiscale investigation of few graphene layers grown on 6H-SiC(000-1) under ultrahigh vacuum (UHV) conditions is presented. At 100-μm scale, the authors show that the UHV growth yields few layer graphene (FLG) with an average thickness given by Auger spectroscopy between 1 and 2 graphene planes. At the same scale, electron diffraction reveals a significant rotational disorder between the first graphene layer and the SiC surface, although well-defined preferred orientations exist. This is confirmed at the nanometer scale by scanning tunneling microscopy (STM). Finally, STM (at the nm scale) and Raman spectroscopy (at the μm scale) show that the FLG stacking is turbostratic, and that the domain size of the crystallites ranges from 10 to 100 nm. The most striking result is that the FLGs experience a strong compressive stress that is seldom observed for graphene grown on the C face of SiC substrates.