There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

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

Redox‐Based Resistive Switching Memories – Nanoionic Mechanisms, Prospects, and Challenges

Electrochemical energy storage technology is based on devices capable of exhibiting high energy density (batteries) or high power density (electrochemical capacitors). There is a growing need, for current and near-future applications, where both high energy and high power densities are required in the same material. Pseudocapacitance, a faradaic process involving surface or near surface redox reactions, offers a means of achieving high energy density at high charge–discharge rates. Here, we focus on the pseudocapacitive properties of transition metal oxides. First, we introduce pseudocapacitance and describe its electrochemical features. Then, we review the most relevant pseudocapacitive materials in aqueous and non-aqueous electrolytes. The major challenges for pseudocapacitive materials along with a future outlook are detailed at the end.

https://hal.archives-ouvertes.fr/hal-01171774/document

Pseudocapacitive oxide materials for high-rate electrochemical energy storage

Approaches, Derivatives and Applications Vasilios Georgakilas,† Michal Otyepka,‡ Athanasios B. Bourlinos,‡ Vimlesh Chandra, Namdong Kim, K. Christian Kemp, Pavel Hobza,‡,§,⊥ Radek Zboril,*,‡ and Kwang S. Kim* †Institute of Materials Science, NCSR “Demokritos”, Ag. Paraskevi Attikis, 15310 Athens, Greece ‡Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology, San 31, Hyojadong, Namgu, Pohang 790-784, Korea Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo naḿ. 2, 166 10 Prague 6, Czech Republic

Functionalization of Graphene: Covalent and Non-Covalent Approaches, Derivatives and Applications

An excellent enzyme biosensor based on Sb-doped SnO2 nanowires.

Cobalt oxide
 nanowire array films have been prepared on large-area metallic substrates via a topochemical conversion route and have been demonstrated as advanced anode materials for high-performance lithium-ion batteries. Compared to previous reports, the cobalt oxide nanowire array electrodes will have good contact with the conducting substrates and an open space between neighboring nanowires, which provide an express pathway for charge transfer and facilitate diffusion of electrolyte into the inner region of the electrode. Besides these strengths, other ancillary materials such as binders and conductive additives are not required to enhance the system's conductivity and stability. After 50 successive cycles, the cobalt nanowire arrays are capable of retaining a specific capacity of 743 mAh g−1 with a very small capacity fading of 0.13% per cycle.

Topochemical synthesis of cobalt oxide nanowire arrays for high performance binderless lithium ion batteries

3D aloe-like SnO2 nanostructures were synthesized by a simple hydrothermal method. The scanning electron microscopy result indicated that this unique structure was assembled by leaf-like sheets, which consisted of large amount of small protrusive nanosheets with width of 5–10 nm. The sensor fabricated by aloe-like SnO2 nanostructures exhibited an excellent response and selectivity to ethanol. The developed sensor can detect ethanol as low as 50 ppb at 285 °C. The ultrasensitive ethanol detection was probably related to the less agglomerative and thinner structure of aloe-like SnO2. The modulation of the conductance of aloe-like SnO2 by the small nanosheets could also be considered to explain the ultrasensitive behavior to the low concentration of ethanol.

Ultrasensitive ethanol sensor based on 3D aloe-like SnO2

The optical properties of ZnO sheets electrodeposited on ITO glass

Preventing the stacking of ultrathin 2D carbon nanostructures is a very important research theme in the field of energy storage. In this work, hierarchical porous carbon microrods (HPCMs) composed of vertically aligned graphene-like nanosheets are successfully fabricated via a facile Mg(OH)2-templating method. The unique structure of the HPCMs is a desirable combination of 1D hierarchical structures, vertically aligned graphenes, and porous graphenes. With the hierarchical structure and pores, high specific surface area, large pore volume, and ideal charge transport and ion diffusion pathways, HPCMs are potential candidates for high-performance electrode materials. When used as an anode for Li-ion batteries, the HPCM electrode exhibits excellent capability (1150 mA h g−1 at 0.1 A g−1), rate performance (246 mA h g−1 at 10 A g−1), and cycling stability (833 mA h g−1 after 700 cycles at 1 A g−1), with measurements superior to those of natural graphite and many graphene-based anodes.

Taihong Wang

Papers

An excellent enzyme biosensor based on Sb-doped SnO2 nanowires.

Topochemical synthesis of cobalt oxide nanowire arrays for high performance binderless lithium ion batteries

Ultrasensitive ethanol sensor based on 3D aloe-like SnO2

The optical properties of ZnO sheets electrodeposited on ITO glass

Hierarchical porous carbon microrods composed of vertically aligned graphene-like nanosheets for Li-ion batteries