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

In this critical review, metal oxides-based materials for electrochemical supercapacitor (ES) electrodes are reviewed in detail together with a brief review of carbon materials and conducting polymers. Their advantages, disadvantages, and performance in ES electrodes are discussed through extensive analysis of the literature, and new trends in material development are also reviewed. Two important future research directions are indicated and summarized, based on results published in the literature: the development of composite and nanostructured ES materials to overcome the major challenge posed by the low energy density of ES (476 references).

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A review of electrode materials for electrochemical supercapacitors

Nanocrystals are fundamental to modern science and technology. Mastery over the shape of a nanocrystal enables control of its properties and enhancement of its usefulness for a given application. Our aim is to present a comprehensive review of current research activities that center on the shape-controlled synthesis of metal nanocrystals. We begin with a brief introduction to nucleation and growth within the context of metal nanocrystal synthesis, followed by a discussion of the possible shapes that a metal nanocrystal might take under different conditions. We then focus on a variety of experimental parameters that have been explored to manipulate the nucleation and growth of metal nanocrystals in solution-phase syntheses in an effort to generate specific shapes. We then elaborate on these approaches by selecting examples in which there is already reasonable understanding for the observed shape control or at least the protocols have proven to be reproducible and controllable. Finally, we highlight a number of applications that have been enabled and/or enhanced by the shape-controlled synthesis of metal nanocrystals. We conclude this article with personal perspectives on the directions toward which future research in this field might take.

Shape‐Controlled Synthesis of Metal Nanocrystals: Simple Chemistry Meets Complex Physics?

Graphene’s success has shown that it is possible to create stable, single and few-atom-thick layers of van der Waals materials, and also that these materials can exhibit fascinating and technologically useful properties. Here we review the state-of-the-art of 2D materials beyond graphene. Initially, we will outline the different chemical classes of 2D materials and discuss the various strategies to prepare single-layer, few-layer, and multilayer assembly materials in solution, on substrates, and on the wafer scale. Additionally, we present an experimental guide for identifying and characterizing single-layer-thick materials, as well as outlining emerging techniques that yield both local and global information. We describe the differences that occur in the electronic structure between the bulk and the single layer and discuss various methods of tuning their electronic properties by manipulating the surface. Finally, we highlight the properties and advantages of single-, few-, and many-layer 2D materials in...

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Progress, Challenges, and Opportunities in Two-Dimensional Materials Beyond Graphene

Rechargeable lithium-sulfur batteries.

The invention provides a gas diffusion layer, which comprises a conductive porous support body and a hydrophobic layer, wherein the hydrophobic layer coats the surface of the conductive porous support body and a pore inner wall of the conductive porous support body; and the material of the conductive porous support body is selected from conductive ceramic. With the conductive ceramic as the material of the conductive porous support body of the gas diffusion layer, the gas diffusion layer has relatively high electrical conductivity and relatively high bending strength; and the gas diffusion layer obtained from the material of the conductive porous support body can be used for preparing a high-performance metal-air battery.

Gas diffusion layer, preparation method and metal-air battery

Using a coating layer to modify the separator in a practical Li metal battery has attracted wide attention; however, its function on Li-ion diffusion and Li plating/stripping has not been systematically investigated. Herein, in situ electrochemical Raman characterization using modified coin cell configuration is employed to directly reveal the anion adsorption mechanism of the coating layer. The adsorption ability of the MOF-based coating layer on the commercial separator is able to preserve high concentration of anions near the electrolyte/Li interface, which generates high local Li-ion concentration that delays the drain of Li+ to uniform Li plating. The feasible and large-area fabrication of GO/ZIF-8-modified separator enables the assembly of pouch cell strictly following practical parameters. 0.4 Ah pouch cell (Li/NCM811) delivers stable capacity for over 100 cycles. The deep understanding of the mechanism of how a coating layer affects Li plating behavior is helpful for the designing and preparation of high-performance separators for Li metal batteries.

Revealing Anion Adsorption Mechanism for Coating Layer on Separator toward Practical Li Metal Batteries.

Carbon nanomaterials have advanced rapidly over the last two decades and are among the most promising materials that have already changed and will keep on changing human life. Development of synthetic methodologies for these materials, therefore, has been one of the most important subjects of carbon nanoscience and nanotechnology, and forms the basis for investigating the physicochemical properties and applications of carbon nanomaterials. In this Research News article, several synthetic strategies, including solvothermal reduction, solvothermal pyrolysis, hydrothermal carbonization, and soft-chemical exfoliation are specifically discussed and highlighted, which have been developed for the synthesis of novel carbon nanomaterials over the last decade.

Synthetic Methodologies for Carbon Nanomaterials

Colloidal Group 13–Group 15 semiconductor nanocrystals (III–V NCs) have been the subject of intensive studies during the last two decades because of rich phenomena associated with quantum confinement. However, studies of III–V NCs are restricted owing to synthetic difficulties. As a consequence of the attractive applications as luminescence probes for bioimaging and as photovoltaic devices, InP NCs have become the most extensively studied III–V system. The synthetic studies of InP NCs are therefore more advanced compared to other III–V systems. By adaptating Wells0 dehalosilylation reaction, some feasible synthetic methods for colloidal InP NCs have been established by several groups. These methods usually involve the reaction of an indium salt with tris(trimethylsilyl)phosphine, P(TMS)3, in a high-boiling-point solvent at high temperatures. At first, Micic et al. chose coordinating solvents (e.g., trioctylphosphine oxide (TOPO) and trioctylphosphine (TOP)) as the reaction medium for the synthesis. To obtain crystalline NCs, growth must be carried out over a long period of time (up to seven days). Even then, the assynthesized NCs showed a broad size distribution, and a further size-selective post-treatment was required to achieve monodispersity. Later, Battaglia and Peng further developed this synthesis by replacing the phosphorous-based coordinating solvent with a noncoordinating one, such as octadecene, and using fatty acids as capping ligands. This synthetic variation not only greatly shortened the reaction time to a few hours, but also generated monodisperse InP NCs without any size sorting. Recently, Xu et al. showed that InP NCs of similar quality could also be rapidly produced in some weak coordinating solvents such as fatty-acid esters. However, all of these methods are dependent on the use of expensive P(TMS)3 precursor as the phosphorus source. This results in a high cost, hampering scale-up of the synthesis. To decrease the cost of the synthesis, a few phosphorous compounds, such as In(tBu2P)3 and Na3P, as well as white phosphorus (P4) have been explored as alternative phosphorus sources. However, the replacement of P(TMS)3 by In(tBu2P)3 or Na3P leads to much less control over the particle size. Moreover, the use of these phosphorus sources brings about some new problems. For example, the synthesis of the organometallic precursor is complex and also highcost, and the preparation of Na3P requires a handling of hazardous and pyrophoric sodium metal and P4. [17] When using the simplest phosphorus source, that is, P4, the syntheses are usually conducted under hydrothermal or solvothermal conditions; the as-synthesized InP NCs are polydisperse and aggregated, giving rise to very low quality. Recently, our group reported that colloidal InP NCs could be prepared using a wet-chemical reduction approach in which P4 and LiBH(C2H5)3 (superhydride) were involved. [22] However, the as-prepared NCs showed a broad size distribution. Therefore, it is still a big challenge to explore an alternative economic phosphorus source for the synthesis of InP NCs of an acceptable quality. As phosphorus halides, such as PCl3, can be reduced to elemental phosphorus with extremely high activity, these compounds may be superior phosphorus sources to P4 for the synthesis of InP NCs. It is anticipated that chemical reaction between freshly reduced indium and phosphorus results in a more rapid nucleation burst, which favors the formation of higher-quality NCs. Herein, we report the first example of using PCl3 to synthesize high-quality InP NCs through a coreduction colloidal approach. The synthesis was carried out in octadecene in the presence of stearic acid as capping ligand; the reactions involve simultaneous reduction of In(OAc)3 and PCl3 with superhydride. The hot-injection method, which has been extensively adopted for the colloidal synthesis of monodisperse NCs, is however inapplicable to our system owing to the low boiling point of PCl3 (76 8C). We thus have to carry out the redox reactions at a low temperature (ca. 40 8C) to retain PCl3 in the starting solution, and then elevate the temperature for the NC growth. Figure 1 depicts an X-ray diffraction (XRD) pattern and a transmission electron microscopy (TEM) image of a typical sample grown at 250 8C for 4 h. All detectable diffraction peaks in Figure 1a can be indexed to those of the zinc blende structure InP (ICDD PDF Card No. 73-1983). The broad nature of these peaks indicates the extremely small size of the particles. Figure 1b shows that the InP NCs are dot-shaped and quasi-monodisperse. The average particle size is about (3.5 0.5) nm based on statistical sampling of this image. These results clearly demonstrate that the present synthetic method is effective to generate InP NCs of relatively high quality. The growth process of InP NCs was investigated by monitoring the UV/Vis absorption spectra of samples grown [*] Dr. Z. Liu, D. Xu, J. Zhang, Dr. Z. Sun, Prof. J. Fang Department of Chemistry State University of New York at Binghamton Binghamton, NY 13902 (USA) Fax: (+1)607-777-4478 E-mail: jfang@binghamton.edu

Coreduction Colloidal Synthesis of III—V Nanocrystals: The Case of InP.

Ever-growing development of Li-ion battery has urged the exploitation of new materials as electrodes. Here, SnxTi1-xO2 solid-solution nanomaterials were prepared by aqueous solution method. The morphology, structures, and electrochemical performance of SnxTi1-xO2 nanoparticles were systematically investigated. The results indicate that Ti atom can replace the Sn atom to enter the lattice of SnO2 to form substitutional solid-solution compounds. The capacity of the solid solution decreases while the stability is improved with the increasing of the Ti content. Solid solution with x of 0.7 exhibits the optimal electrochemical performance. The Sn0.7Ti0.3O2 was further modified by highly conductive graphene to enhance its relatively low electrical conductivity. The Sn0.7Ti0.3O2/graphene composite exhibits much improved rate performance, indicating that the SnxTi1-xO2 solid solution can be used as a potential anode material for Li-ion batteries.

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Zhaoping Liu

Papers

Gas diffusion layer, preparation method and metal-air battery

Revealing Anion Adsorption Mechanism for Coating Layer on Separator toward Practical Li Metal Batteries.

Synthetic Methodologies for Carbon Nanomaterials

Coreduction Colloidal Synthesis of III—V Nanocrystals: The Case of InP.

Synthesis and electrochemical performance of graphene wrapped Sn x Ti 1− x O 2 nanoparticles as an anode material for Li-ion batteries