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

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

[Wu, Zhong-Shuai; Ren, Wencai; Wen, Lei; Gao, Libo; Zhao, Jinping; Chen, Zongping; Zhou, Guangmin; Li, Feng; Cheng, Hui-Ming] Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China;Ren, WC (reprint author), Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, 72 Wenhua Rd, Shenyang 110016, Peoples R China;wcren@imraccn cheng@imraccn

Graphene Anchored with Co 3 O 4 Nanoparticles as Anode of Lithium Ion Batteries with Enhanced Reversible Capacity and Cyclic Performance

In this paper, the use of nanostructured anode materials for rechargeable lithium-ion batteries (LIBs) is reviewed. Nanostructured materials such as nano-carbons, alloys, metal oxides, and metal sulfides/nitrides have been used as anodes for next-generation LIBs with high reversible capacity, fast power capability, good safety, and long cycle life. This is due to their relatively short mass and charge pathways, high transport rates of both lithium ions and electrons, and other extremely charming surface activities. In this review paper, the effect of the nanostructure on the electrochemical performance of these anodes is presented. Their synthesis processes, electrochemical properties, and electrode reaction mechanisms are also discussed. The major goals of this review are to give a broad overview of recent scientific researches and developments of anode materials using novel nanoscience and nanotechnology and to highlight new progresses in using these nanostructured materials to develop high-performance LIBs. Suggestions and outlooks on future research directions in this field are also given.

Recent developments in nanostructured anode materials for rechargeable lithium-ion batteries

Preceramic polymers were proposed over 30 years ago as precursors for the fabrication of mainly Si-based advanced ceramics, generally denoted as polymer-derived ceramics (PDCs). The polymer to ceramic transformation process enabled significant technological breakthroughs in ceramic science and technology, such as the development of ceramic fibers, coatings, or ceramics stable at ultrahigh temperatures (up to 2000°C) with respect to decomposition, crystallization, phase separation, and creep. In recent years, several important advances have been achieved such as the discovery of a variety of functional properties associated with PDCs. Moreover, novel insights into their structure at the nanoscale level have contributed to the fundamental understanding of the various useful and unique features of PDCs related to their high chemical durability or high creep resistance or semiconducting behavior. From the processing point of view, preceramic polymers have been used as reactive binders to produce technical ceramics, they have been manipulated to allow for the formation of ordered pores in the meso-range, they have been tested for joining advanced ceramic components, and have been processed into bulk or macroporous components. Consequently, possible fields of applications of PDCs have been extended significantly by the recent research and development activities. Several key engineering fields suitable for application of PDCs include high-temperature-resistant materials (energy materials, automotive, aerospace, etc.), hard materials, chemical engineering (catalyst support, food- and biotechnology, etc.), or functional materials in electrical engineering as well as in micro/nanoelectronics. The science and technological development of PDCs are highly interdisciplinary, at the forefront of micro- and nanoscience and technology, with expertise provided by chemists, physicists, mineralogists, and materials scientists, and engineers. Moreover, several specialized industries have already commercialized components based on PDCs, and the production and availability of the precursors used has dramatically increased over the past few years. In this feature article, we highlight the following scientific issues related to advanced PDCs research: (1) General synthesis procedures to produce silicon-based preceramic polymers.
(2) Special microstructural features of PDCs.
(3) Unusual materials properties of PDCs, that are related to their unique nanosized microstructure that makes preceramic polymers of great and topical interest to researchers across a wide spectrum of disciplines.
(4) Processing strategies to fabricate ceramic components from preceramic polymers.
(5) Discussion and presentation of several examples of possible real-life applications that take advantage of the special characteristics of preceramic polymers. Note: In the past, a wide range of specialized international symposia have been devoted to PDCs, in particular organized by the American Ceramic Society, the European Materials Society, and the Materials Research Society. Most of the reviews available on PDCs are either not up to date or deal with only a subset of preceramic polymers and ceramics (e.g., silazanes to produce SiCN-based ceramics). Thus, this review is focused on a large number of novel data and developments, and contains materials from the literature but also from sources that are not widely available.

Polymer-Derived Ceramics: 40 Years of Research and Innovation in Advanced Ceramics

Strategies for the Stabilization of Zn Metal Anodes for Zn‐Ion Batteries

2010 WILEY-VCH Verlag Gm Carbon nanotubes (CNTs) have ultrahigh strength, high electrical conductivities, high thermal conductivities, electric field emissions, gas sensitivities, and other functional properties. These outstandingmechanical, physical, andmultifunctional properties of CNTs, in combination with their unique 1D nanostructures with high specific areas, allow for a wide range of potential applications such as structural fibers, composites, multifunctional fabrics, and devices. The fabrication of CNTs into a continuous multifunctional CNT yarn is an important step towards these macroscopic applications. Several processes are under development to fabricate macroscopic CNT fibers, including wet spinning of CNTs from polymer dispersions or acid dispersions, dry spinning from aligned CNT matrices, and direct spinning from chemical vapor deposition (CVD) reactions. While the development of a continuous and weavable pure CNT yarn remains a major challenge in the fabrications, CNT yarns so far obtained from the different processes are monolithic in structure, although a hollow yarn was demonstrated from a wet drawing process. One the other hand, CNT sheets or films have been fabricated by drying CNT dispersions, drawing [19,20] or infiltrating of CNT arrays, and by CVD spinning. These 2D CNT assemblies have demonstrated applications as catalyst supports, molecular sieves, infiltrators, conductors, electromagnetic shields, capacitors, and artificial tissues. If CNTs can be made into continuous yarns with a layered structure, they will combine the weavable property of fibers and the structural characteristic of films and can be adopted for numerous applications. In the present work, we report the fabrication of a novel continuous yarn of CNTs with a multiple-layer structure by the CVD spinning process. The yarn consists of multiple monolayers of CNTs concentrically assembled in seamless tubules along the yarn axis. This layered structure is assembled from CNTs produced in a gas flow from the CVD reaction with a mixed acetone and ethanol carbon source. The development of a water-densification and spinning process allows us to spin the CNT yarn continuously with a yarn length of over several kilometers and a yarn quality close to conventional textile yarns. The CNTyarn can be controlled to be either hollow or monolithic with compacted or detached CNTmonolayers by controlling the spinning process. This layered multifunctional CNT yarns combine superior mechanical properties, electrical conductivities, and surface structures, and have potential applications as structural fibers, composites, woven fabrics, catalyst supports, energy storage materials, artificial tissue, and so on. The fabrication of a CNT yarn by the CVD spinning process relies on the assembly of CNTs in the gas flow by van der Waals interactions. The CNTs assemble in the gas flow when produced in a sufficiently high yield with a high purity such that interaction occurs. Their assembly is, therefore, greatly dependent on the chemistry of the carbon sources. The assembly of CNTs in the gas flow forms a continuous sock-like CNT integrate, which can be mechanically spun out into a CNT yarn. This process was first demonstrated with ethanol as a carbon source and a twisting spinning performed inside the reactor. Recent work reports that a CNT yarn spun from this process possesses ultrahigh strength after densification of the yarn with an acetone vapor. The spinning of multilayered CNT yarns in this work is based on our discovery that CNTs can self-assemble into a multilayered CNT ‘sock’ in the gas flow when a mixture of acetone and ethanol is used as the carbon source. The synthesis was conducted by the injection of the carbon source dispersed with ferrocene and thiophene into a heated gas-flow reactor in flowing hydrogen (Fig. 1a). The CNT layers in the sock, which can be clearly seen in the gas flow, are continuous, concentric, and discrete (Fig. 1b). The CNTsock was initiated from the upper gas flow and produced continuously, traveling downstream with the gases. The assembly of the CNTs is believed to be associated with the interaction of gas molecules, which drive the CNTs towards the outer circumference of the gas flow where they interact mechanically. The formation of the multilayer structure may result from the higher concentration of CNTs in the gas flow because the CNT yield ( 240mg h ) from the mixed carbon source is double that from ethanol alone ( 110mg h ). The layered CNT sock was densified with water after it came out of the reactor. This is realized by connecting a water tank to the end of the CVD reactor (Fig. 1a). The water tank simultaneously encloses the gas-flow system and provides a soft connection between the reactor and air. This configuration allows the CNT assembly to be drawn out continuously from the high-temperature, hydrogen-containing reactor into the open air in a safe and controlled manner. The CNT sock shrinks immediately into a fiber upon arriving at the water surface (Fig. 1c). The fiber is directed around a rotator in the water and is pulled out into air from the other side (Fig. 1d). It is then directed onto the second spool that rotates in acetone for washing and

Continuous multilayered carbon nanotube yarns.

https://ro.uow.edu.au/cgi/viewcontent.cgi?article=4028&context=aiimpapers

Feng Hou

Papers

Strategies for the Stabilization of Zn Metal Anodes for Zn‐Ion Batteries

Continuous multilayered carbon nanotube yarns.

Engineering of lithium-metal anodes towards a safe and stable battery

Recent progress on the recycling technology of Li-ion batteries

Nitrogen Reduction to Ammonia on Atomic‐Scale Active Sites under Mild Conditions