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

Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

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

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Lithium (Li)-ion batteries (LIB) have governed the current worldwide rechargeable battery market due to their outstanding energy and power capability. In particular, the LIB's role in enabling electric vehicles (EVs) has been highlighted to replace the current oil-driven vehicles in order to reduce the usage of oil resources and generation of CO2 gases. Unlike Li, sodium is one of the more abundant elements on Earth and exhibits similar chemical properties to Li, indicating that Na chemistry could be applied to a similar battery system. In the 1970s-80s, both Na-ion and Li-ion electrodes were investigated, but the higher energy density of Li-ion cells made them more applicable to small, portable electronic devices, and research efforts for rechargeable batteries have been mainly concentrated on LIB since then. Recently, research interest in Na-ion batteries (NIB) has been resurrected, driven by new applications with requirements different from those in portable electronics, and to address the concern on Li abundance. In this article, both negative and positive electrode materials in NIB are briefly reviewed. While the voltage is generally lower and the volume change upon Na removal or insertion is larger for Na-intercalation electrodes, compared to their Li equivalents, the power capability can vary depending on the crystal structures. It is concluded that cost-effective NIB can partially replace LIB, but requires further investigation and improvement.

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Electrode Materials for Rechargeable Sodium-Ion Batteries: Potential Alternatives to Current Lithium-Ion Batteries

Electrochemical behavior of perovskite-type Ce1−xCaxVO3 under reducing conditions

Properties of supported Pt-containing granular (Pt/Ce0.75Zr0.25O2–δ) and monolithic structured (Pt/Ce0.75Zr0.25O2–δ /η-Al2O3 /FeCrAl) catalysts were studied in the methanol decomposition to syngas for feeding solid oxide fuel cells (SOFC). The application of the monolithic structured catalyst in the methanol decomposition reaction was shown to be promising. The addition of a small oxygen amount to the initial mixture was found to prevent the formation of carbon, thus enhancing the stability of catalyst operation. The proposed monolithic structured catalyst 0.15 wt.% Pt/8 wt.% Ce0.75Zr0.25O2–δ /6 wt.% η-Al2O3 /FeCrAl at atmospheric pressure, temperature of ca. 400 °C, feed rate of the reaction mixture 5.6 L/(gcat·h) and volumetric ratio СН3ОН/air = 1 can provide the complete conversion of methanol to syngas with the total content of H2 and СО of ca. 64 vol.% and the syngas output of ca. 6.7 L(Н2 + СО)/(gcat· h).

Decomposition of methanol to syngas on supported Pt-containing catalysts

Solid-state electrochemistry is a rapidly developing scientific field that integrates many aspects of the classical electrochemical science and engineering, solid-state chemistry and physics, materials science, heterogeneous catalysis, and other areas of physical chemistry. This field comprises, but is not limited to, electrochemistry of solid materials, thermodynamics and kinetics of electrochemical reactions involving at least one solid phase, transport of ions and electrons in solids and interactions between solid, liquid, and/or gaseous phases whenever these processes are essentially determined by properties of solids and are relevant to the electrochemical reactions, and a variety of practical applications using solid electrolytes, mixed ionic– electronic conductors, and solid-state electrochemical reactions. The range of these applications includes many types of batteries, fuel cells, capacitors and accumulators, numerous sensors and analytical appliances, electrochemical gas pumps and compressors, electrochromic and memory devices, ceramic membranes with ionic or mixed ionic–electronic conductivity, solid-state electrolyzers and electrocatalytic reactors, synthesis of new materials with improved properties, and corrosion protection. The first fundamental discoveries considered now as the foundation of solid-state electrochemistry were made in the nineteenth and first half of the twentieth centuries by M. Faraday, E.

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Methodological aspects of electrochemical science and technology: a selection of reviews

Oxygen transport properties of perovskite-type SrCe1-xYxO3-δ (x = 0.05–0.10), exhibiting protonic transport in hydrogen-containing reducing atmospheres and mixed oxygen-ionic and ptype electronic conductivity at oxygen partial pressures close to atmospheric, were studied at 973– 1223 K under oxidizing conditions. The oxygen transference numbers of SrCe(Y)O3-δ in air vary in the range 0.37–0.80, decreasing when temperature increases. The oxygen permeability is significantly affected by the hole conduction, which influences both bulk ambipolar conductivity and surface exchange kinetics. The average thermal expansion coefficients of SrCe1-xYxO3-δ ceramics, calculated from dilatometric data in air, are (11.1–11.3)×10-6 K-1 at 373–1373 K.

Transport Properties and Thermal Expansion of SrCe(Y)O3-δ Ceramics

Following Chapter 5 where state-of-the-art fuel cell technologies are reviewed, this chapter presents a short survey on the novel electrode materials for the solid oxide fuel cells (SOFCs) with oxygen ion- and proton-conducting electrolytes. Attention is primarily drawn to most recent research studies published during the past few years. Numerous literature data on the electrode performance and key properties of the electrode materials are systematically compared, including the total electrical conductivity, thermal expansion, and reactivity with solid electrolytes. A comparison of the cell performance with various fuels and cell components is also presented. In addition to the fuel cells, related applications such as high-temperature electrolyzers of steam and carbon dioxide are briefly considered.

Vladislav V. Kharton

Papers

Electrochemical behavior of perovskite-type Ce1−xCaxVO3 under reducing conditions

Decomposition of methanol to syngas on supported Pt-containing catalysts

Methodological aspects of electrochemical science and technology: a selection of reviews

Transport Properties and Thermal Expansion of SrCe(Y)O3-δ Ceramics

Electrodes for High‐Temperature Electrochemical Cells: Novel Materials and Recent Trends