다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Supercapacitors, also called ultracapacitors or electrochemical capacitors, store electrical charge on high-surface-area conducting materials. Their widespread use is limited by their low energy storage density and relatively high effective series resistance. Using chemical activation of exfoliated graphite oxide, we synthesized a porous carbon with a Brunauer-Emmett-Teller surface area of up to 3100 square meters per gram, a high electrical conductivity, and a low oxygen and hydrogen content. This sp 2 -bonded carbon has a continuous three-dimensional network of highly curved, atom-thick walls that form primarily 0.6- to 5-nanometer-width pores. Two-electrode supercapacitor cells constructed with this carbon yielded high values of gravimetric capacitance and energy density with organic and ionic liquid electrolytes. The processes used to make this carbon are readily scalable to industrial levels.

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Carbon-based Supercapacitors Produced by Activation of Graphene

Kenji Sumida, David L. Rogow, Jarad A. Mason, Thomas M. McDonald, Eric D. Bloch, Zoey R. Herm, Tae-Hyun Bae, Jeffrey R. Long

Carbon Dioxide Capture in Metal–Organic Frameworks

Carbon properties and their role in supercapacitors

Current methods for the characterization of microporous solids via adsorption of gases and vapours are actually being revised due to the non-applicability of the Kelvin equation in small pores and the failure of empirical equations, such as Dubinin-Radushdevich's, for solids with a wide range of micropore sizes. In the present work we propose a three-dimensional lattice-gas Ising model, with nearest-neighbor and next-nearest-neighbor interactions, in an external field representing the gas-solid interaction for slit-shaped micropores. This model is shown to represent correctly the fluid behavior predicted by more complete models and has the advantage of being simple and fast for Monte Carlo simulation. The model is then applied to the characterization of activated carbons (which are essentially microporous) using nitrogen adsorption (77 K) experimental results. Since the used activated carbons are essentially heterogeneous, an adsorptive energy distribution with a given mean adsorption energy and a given dispersion u1 for each adsorbed layer had to be considered. The analysis of adsorption data for non-porous carbons (of the same type as the microporous ones) allows the determination of model parameters (i.e. gas-solid and gas-gas interaction energies). These parameters are finally used to simulate differently sized slit-shaped pores and this, in turn, allows the determination of the pore size distribution by fitting experimental isotherms for microporous carbons.

A lattice-gas model for adsorption in microporous solids

A new route for the synthesis of SiC–MoSi2 ceramic composite materials

Effect of chromium addition on the behaviour of iron/activated carbon catalysts for carbon monoxide hydrogenation

The Poisson Ratio of Porous Materials

This chapter investigates the effects of the surface chemistry of a carbon molecular sieve on the adsorption of propane and propylene. The carbon molecular sieve (CMS) was oxidized by two different agents, and thermal treatments under vacuum and different atmospheres were used to selectively remove the oxygen surface groups and the highly active sites. Adsorption microcalorimetry of propane reveals that the surface chemistry of the carbons has no relevance in the heat of adsorption. However, the amount of propane adsorbed can vary in the oxidized carbon with the progressive removal of the oxygen groups that may block part of the microporosity. In the case of propylene, the adsorption strength in the oxidized carbons is higher than in the non oxidized CMS, although it does not depend on the out-gassing temperature used. The adsorption isotherms follow the same tendency with the thermal treatments in both adsorbates. When the oxidized samples are treated at high temperature (1073 K) in H 2 the surface is stabilized, and therefore, a heat of adsorption profile very similar to the non oxidized carbon is obtained.

Francisco Rodríguez-Reinoso

Papers

A lattice-gas model for adsorption in microporous solids

A new route for the synthesis of SiC–MoSi2 ceramic composite materials

Effect of chromium addition on the behaviour of iron/activated carbon catalysts for carbon monoxide hydrogenation

The Poisson Ratio of Porous Materials

Effect of thermal treatments on the surface chemistry of oxidized activated carbons