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

We introduce the 2D counterpart of layered black phosphorus, which we call phosphorene, as an unexplored p-type semiconducting material. Same as graphene and MoS2, single-layer phosphorene is flexible and can be mechanically exfoliated. We find phosphorene to be stable and, unlike graphene, to have an inherent, direct, and appreciable band gap. Our ab initio calculations indicate that the band gap is direct, depends on the number of layers and the in-layer strain, and is significantly larger than the bulk value of 0.31–0.36 eV. The observed photoluminescence peak of single-layer phosphorene in the visible optical range confirms that the band gap is larger than that of the bulk system. Our transport studies indicate a hole mobility that reflects the structural anisotropy of phosphorene and complements n-type MoS2. At room temperature, our few-layer phosphorene field-effect transistors with 1.0 μm channel length display a high on-current of 194 mA/mm, a high hole field-effect mobility of 286 cm2/V·s, and an...

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Phosphorene: An Unexplored 2D Semiconductor with a High Hole Mobility

There is still an ongoing effort to search for sustainable, clean and highly efficient energy generation to satisfy the energy needs of modern society. Among various advanced technologies, electrocatalysis for the oxygen evolution reaction (OER) plays a key role and numerous new electrocatalysts have been developed to improve the efficiency of gas evolution. Along the way, enormous effort has been devoted to finding high-performance electrocatalysts, which has also stimulated the invention of new techniques to investigate the properties of materials or the fundamental mechanism of the OER. This accumulated knowledge not only establishes the foundation of the mechanism of the OER, but also points out the important criteria for a good electrocatalyst based on a variety of studies. Even though it may be difficult to include all cases, the aim of this review is to inspect the current progress and offer a comprehensive insight toward the OER. This review begins with examining the theoretical principles of electrode kinetics and some measurement criteria for achieving a fair evaluation among the catalysts. The second part of this review acquaints some materials for performing OER activity, in which the metal oxide materials build the basis of OER mechanism while non-oxide materials exhibit greatly promising performance toward overall water-splitting. Attention of this review is also paid to in situ approaches to electrocatalytic behavior during OER, and this information is crucial and can provide efficient strategies to design perfect electrocatalysts for OER. Finally, the OER mechanism from the perspective of both recent experimental and theoretical investigations is discussed, as well as probable strategies for improving OER performance with regards to future developments.

Electrocatalysis for the oxygen evolution reaction: recent development and future perspectives

Preceding the current interest in layered materials for electronic applications, research in the 1960's found that black phosphorus combines high carrier mobility with a fundamental band gap. We introduce its counterpart, dubbed few-layer phosphorene, as a new 2D p-type material. Same as graphene and MoS2, phosphorene is flexible and can be mechanically exfoliated. We find phosphorene to be stable and, unlike graphene, to have an inherent, direct and appreciable band-gap that depends on the number of layers. Our transport studies indicate a carrier mobility that reflects its structural anisotropy and is superior to MoS2. At room temperature, our phosphorene field-effect transistors with 1.0 um channel length display a high on-current of 194 mA/mm, a high hole field-effect mobility of 286 cm2/Vs, and an on/off ratio up to 1E4. We demonstrate the possibility of phosphorene integration by constructing the first 2D CMOS inverter of phosphorene PMOS and MoS2 NMOS transistors.

Phosphorene: A New 2D Material with High Carrier Mobility

Magnetism and ferroelectricity are essential to many forms of current technology, and the quest for multiferroic materials, where these two phenomena are intimately coupled, is of great technological and fundamental importance. Ferroelectricity and magnetism tend to be mutually exclusive and interact weakly with each other when they coexist. The exciting new development is the discovery that even a weak magnetoelectric interaction can lead to spectacular cross-coupling effects when it induces electric polarization in a magnetically ordered state. Such magnetic ferroelectricity, showing an unprecedented sensitivity to ap plied magnetic fields, occurs in 'frustrated magnets' with competing interactions between spins and complex magnetic orders. We summarize key experimental findings and the current theoretical understanding of these phenomena, which have great potential for tuneable multifunctional devices.

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Multiferroics: a magnetic twist for ferroelectricity

All-solid-state lithium-sulfur (Li/S) batteries are promising next-generation energy-storage devices owing to their high capacities and long cycle lives. The Li2 S active material used in the positive electrode has a high theoretical capacity; consequently, nanocomposites composed of Li2 S, solid electrolytes, and conductive carbon can be used to fabricate high-energy-density batteries. Moreover, the active material should be constructed with both micro- and nanoscale ion-conduction pathways to ensure high power. Herein, a Li2 S-Li2 O-LiI positive electrode is developed in which the active material is dispersed in an amorphous matrix. Li2 S-Li2 O-LiI exhibits high charge-discharge capacities and a high specific capacity of 998 mAh g-1 at a 2 C rate and 25 °C. X-ray photoelectron spectroscopy, X-ray diffractometry, and transmission electron microscopy observation suggest that Li2 O-LiI provides nanoscale ion-conduction pathways during cycling that activate Li2 S and deliver large capacities; it also exhibits an appropriate onset oxidation voltage for high capacity. Furthermore, a cell with a high areal capacity of 10.6 mAh cm-2 is demonstrated to successfully operate at 25 °C using a Li2 S-Li2 O-LiI positive electrode. This study represents a major step toward the commercialization of all-solid-state Li/S batteries.

High Capacity Li2 S-Li2 O-LiI Positive Electrodes with Nanoscale Ion-Conduction Pathways for All-Solid-State Li/S Batteries.

Reaction of (Vinylimino)phosphoranes and Related Compounds. Part 18. A Novel Route to 1‐Azaazulenes by the Reaction of β‐Amino Enones with Activated Tropones.

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Microstructure and Charge-discharge Properties of a Li3CuS2 active material for All-Solid-State Batteries

In order to clarify the stability of charge ordered structure (CO) in charge- and spin-frustrated ferrite YbFe2O4, we have investigated changes of the CO structure by partial substitution of Mn2+ for Fe2+ in YbFe2O4 by a transmission electron microscope (TEM), in combination with conventional dielectric measurement It is revealed that subtle substitution of Mn2+ for Fe2+ in YbFe2O4 destroyed drastically the CO structure with the wave vector of q = and, instead, induced polar clustering structure characterized by honeycomb-shaped diffuse scatterings in the reciprocal space The formation of polar clustering structure should be responsible for the characteristic dielectric dispersion

https://iopscience.iop.org/article/10.1088/1742-6596/320/1/012085/pdf

Collapsing processes of charge ordered structure in charge- and spin- frustrated ferrite YbFe2O4

The average and local structures of solid solutions of (1 – x)BiFeO3–xBaTiO3 were investigated. At room temperature, pseudo-cubic phases appear in BaTiO3 compositions with x values ranging from 0.3 to 0.7. The ferroelectricity was not lost even in the cubic structure with the highest ferroelectricity observed at x = 0.3. We used a pair distribution function and an X-ray absorption fine structure to perform a structural analysis to determine the source of this ferroelectricity. These solid solutions’ local structures were consistent with the pure limits of BiFeO3 and BaTiO3, respectively, but when the composition of BaTiO3 was 0.3, a structure peculiar to the structural boundary in the solid solutions appeared. We discovered that the structure had the greatest randomness around this composition by performing a model fit of this local structure. Local structure changes to improve nanoscale dipole interactions while maintaining the ferroelectric long-range order structure. As a result, the domain size grows and the ferroelectricity improves.

https://iopscience.iop.org/article/10.35848/1347-4065/ac835d/pdf

Shigeo Mori

Papers

High Capacity Li2 S-Li2 O-LiI Positive Electrodes with Nanoscale Ion-Conduction Pathways for All-Solid-State Li/S Batteries.

Reaction of (Vinylimino)phosphoranes and Related Compounds. Part 18. A Novel Route to 1‐Azaazulenes by the Reaction of β‐Amino Enones with Activated Tropones.

Microstructure and Charge-discharge Properties of a Li3CuS2 active material for All-Solid-State Batteries

Collapsing processes of charge ordered structure in charge- and spin- frustrated ferrite YbFe2O4

Local structure analysis of BiFeO3-BaTiO3 solid solutions