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.

Self-Reconstruction of Highly Active Nico2o4 with Triple-Continuous Transfer of Electrons, Ions, and Oxygen for Zn-Air Batteries

Electrochemical CO2 conversion has been raised as a promising solution for building a carbon-neutral economy under today's circumstances of increasing energy shortages and air pollution from human activities. Research on electrochemical CO2 reduction reaction (CO2RR) is gradually entering a pilot-scale stage. The use of device-level CO2 electrolysis in the production of value-added chemicals and fuels at a high production rate and selectivity is highly required to make the technology economical and sustainable. With more exploration toward device-level performance optimization, it gradually becomes clear that electrode engineering on structures, surface properties, active site distribution, and density, as well as the electrode–electrolyte interface, is more critical than the intrinsic activity of catalytic sites. Taking this into account, this review focuses on interpreting the design principles in aspects with the aim of enhancing the CO2RR toward a specific product yield and production rate. This mini-review summarizes the advances in this dynamic field in the most recent 5 years, including the fabrication of porous gas diffusion electrodes, and self-supporting electrodes, establishment of tandem or cascade electrode function, as well as tuning of interfacial cation buffering and wettability, and analyze the trends in the future scientific and technological development of device-level CO2 electrolysis. Hopefully, this mini-review could provide some insights into the opportunities in the next-generation electrode design for the industrial carbon cycle. 

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/cnl2.21

Advances in cutting‐edge electrode engineering toward CO
 2
 electrolysis at high current density and selectivity: A mini‐review

There is an increasing interest in a novel type of fuel cells, the solid-acid fuel cells (SAFCs), which are characterized by impermeability to fuels of the electrolyte, high electrocatalytic activity and high CO tolerance of the electrodes. This paper gives a thorough review on the background and recent progress on SAFCs. The operation principle is described in detail. The key problems for the application of SAFCs are suggested and the possible solutions are proposed.

Solid-acid fuel cells

For IT-SOFCs, gas-tight sealing is required between the electrodes and interconnects and between individual cell units to prevent mixing of gas between the anode and the cathode and to provide electrical insulation. Generally, an eligible material should sufficiently seal the adjacent cell components, and more importantly, it should remain stable over long-term high-temperature operation. A specific sealant must exhibit promising thermal stability, chemical stability, mechanical integrity, and sealing ability under severe oxidizing and reducing environments. Until now, several types of seals have been developed, including the rigid seal, compressive seal, and bonded compliant seal. This chapter presents the advantages and disadvantages of different sealing strategies and comprehensively discusses the influence of different components in the sealants on the sealing performance.

Zongping Shao

Papers

Self-Reconstruction of Highly Active Nico2o4 with Triple-Continuous Transfer of Electrons, Ions, and Oxygen for Zn-Air Batteries

Advances in cutting‐edge electrode engineering toward CO 2 electrolysis at high current density and selectivity: A mini‐review

Solid-acid fuel cells

Sealants for IT-SOFCs

Beyond two-dimension: one- and zero-dimensional halide perovskites as new-generation passivators for high-performance perovskite solar cells