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

As a fascinating conjugated polymer, graphitic carbon nitride (g-C3N4) has become a new research hotspot and drawn broad interdisciplinary attention as a metal-free and visible-light-responsive photocatalyst in the arena of solar energy conversion and environmental remediation. This is due to its appealing electronic band structure, high physicochemical stability, and “earth-abundant” nature. This critical review summarizes a panorama of the latest progress related to the design and construction of pristine g-C3N4 and g-C3N4-based nanocomposites, including (1) nanoarchitecture design of bare g-C3N4, such as hard and soft templating approaches, supramolecular preorganization assembly, exfoliation, and template-free synthesis routes, (2) functionalization of g-C3N4 at an atomic level (elemental doping) and molecular level (copolymerization), and (3) modification of g-C3N4 with well-matched energy levels of another semiconductor or a metal as a cocatalyst to form heterojunction nanostructures. The constructi...

Graphitic Carbon Nitride (g-C3N4)-Based Photocatalysts for Artificial Photosynthesis and Environmental Remediation: Are We a Step Closer To Achieving Sustainability?

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

The efficiency of many energy storage technologies, such as rechargeable metal-air batteries and hydrogen production from water splitting, is limited by the slow kinetics of the oxygen evolution reaction (OER). We found that Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3–δ (BSCF) catalyzes the OER with intrinsic activity that is at least an order of magnitude higher than that of the state-of-the-art iridium oxide catalyst in alkaline media. The high activity of BSCF was predicted from a design principle established by systematic examination of more than 10 transition metal oxides, which showed that the intrinsic OER activity exhibits a volcano-shaped dependence on the occupancy of the 3d electron with an e g symmetry of surface transition metal cations in an oxide. The peak OER activity was predicted to be at an e g occupancy close to unity, with high covalency of transition metal–oxygen bonds.

https://science.sciencemag.org/content/sci/early/2011/10/26/science.1212858.full.pdf

A perovskite oxide optimized for oxygen evolution catalysis from molecular orbital principles.

Organic–inorganic perovskite solar cells (PSCs) have delivered the highest power conversion efficiency (PCE) of 25.7% currently, but they are unfortunately limited by several key issues, such as inferior humid and thermal stability, significantly retarding their widespread application. To tackle the instability issue, all-inorganic PSCs have attracted increasing interest due to superior structural, humid and high-temperature stability to their organic–inorganic counterparts. Nevertheless, all-inorganic PSCs with typical CsPbIBr2 perovskite as light absorbers suffer from much inferior PCEs to those of organic–inorganic PSCs. Functional doping is regarded as a simple and useful strategy to improve the PCEs of CsPbIBr2-based all-inorganic PSCs. Herein, we report a monovalent copper cation (Cu+)-doping strategy to boost the performance of CsPbIBr2-based PSCs by increasing the grain sizes and improving the CsPbIBr2 film quality, reducing the defect density, inhibiting the carrier recombination and constructing proper energy level alignment. Consequently, the device with optimized Cu+-doping concentration generates a much better PCE of 9.11% than the pristine cell (7.24%). Moreover, the Cu+ doping also remarkably enhances the humid and thermal durability of CsPbIBr2-based PSCs with suppressed hysteresis. The current study provides a simple and useful strategy to enhance the PCE and the durability of CsPbIBr2-based PSCs, which can promote the practical application of perovskite photovoltaics.

/pdf/monovalent-copper-cation-doping-enables-high-performance-2m495b0t.pdf

Monovalent Copper Cation Doping Enables High-Performance CsPbIBr2-Based All-Inorganic Perovskite Solar Cells

The electrochemical performance of an anode material for asolid oxide fuel cell (SOFC) depends highly on microstruc-ture in addition to composition. In this study, a NiO–yttria-stabilised zirconia (NiO–YSZ) composite with a highly dis-persed microstructure and large pore volume/surface areahas been synthesised by ultrasonic spray pyrolysis (USP)and its electrochemical characteristics has been investigated.For comparison, the electrochemical performance of a con-ventional NiO–YSZ is also evaluated. The power density ofthe zirconia electrolyte-supported SOFC with the synthe-sised anode is ∼392 mW cm –2 at 900 °C and that of the SOFCwith the conventional NiO–YSZ anode is ∼315 mW cm –2 .The improvement is ∼24%. This result demonstrates that thesynthesised NiO–YSZ is a potential alternative anode mate-rial for SOFCs fabricated with a zirconia solid electrolyte. Keywords: Anode, Nanocomposite, Ni-YSZ, Power Density,Solid Oxide Fuel Cell, Ultrasonic Spray Pyrolysis654 © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim FUEL CELLS 11, 2011, No. 5, 654–660

Electrochemical Performance of a Ni and YSZ Composite Synthesised by Ultrasonic Spray Pyrolysis as an Anode for SOFCs

Microscale-decoupled charge-discharge reaction sites for an air electrode with abundant triple-phase boundary and enhanced cycle stability of Zn-Air batteries

Simultaneous reactant accessibility and charge transfer engineering in Co-doped RuO2-supported OCNT for robust rechargeable zinc-air batteries

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/admi.201870039

Lithium–Sulfur Batteries: Dodecylamine-Induced Synthesis of a Nitrogen-Doped Carbon Comb for Advanced Lithium–Sulfur Battery Cathodes (Adv. Mater. Interfaces 9/2018)

Zongping Shao

Papers

Monovalent Copper Cation Doping Enables High-Performance CsPbIBr2-Based All-Inorganic Perovskite Solar Cells

Electrochemical Performance of a Ni and YSZ Composite Synthesised by Ultrasonic Spray Pyrolysis as an Anode for SOFCs

Microscale-decoupled charge-discharge reaction sites for an air electrode with abundant triple-phase boundary and enhanced cycle stability of Zn-Air batteries

Simultaneous reactant accessibility and charge transfer engineering in Co-doped RuO2-supported OCNT for robust rechargeable zinc-air batteries

Lithium–Sulfur Batteries: Dodecylamine-Induced Synthesis of a Nitrogen-Doped Carbon Comb for Advanced Lithium–Sulfur Battery Cathodes (Adv. Mater. Interfaces 9/2018)