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

QUANTUM ESPRESSO is an integrated suite of computer codes for electronic-structure calculations and materials modeling, based on density-functional theory, plane waves, and pseudopotentials (norm-conserving, ultrasoft, and projector-augmented wave). The acronym ESPRESSO stands for opEn Source Package for Research in Electronic Structure, Simulation, and Optimization. It is freely available to researchers around the world under the terms of the GNU General Public License. QUANTUM ESPRESSO builds upon newly-restructured electronic-structure codes that have been developed and tested by some of the original authors of novel electronic-structure algorithms and applied in the last twenty years by some of the leading materials modeling groups worldwide. Innovation and efficiency are still its main focus, with special attention paid to massively parallel architectures, and a great effort being devoted to user friendliness. QUANTUM ESPRESSO is evolving towards a distribution of independent and interoperable codes in the spirit of an open-source project, where researchers active in the field of electronic-structure calculations are encouraged to participate in the project by contributing their own codes or by implementing their own ideas into existing codes.

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QUANTUM ESPRESSO: a modular and open-source software project for quantum simulations of materials

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

We report that the doping of energetic nitrogen cations (N2+) on graphene effectively controls the local N–C bonding structures and the π-band of graphene critically depending on ion energy Ek (100 eV ≤ Ek ≤ 500 eV) by using a combined study of photoemission spectroscopy and density functional theory (DFT) calculations. With increasing Ek, we find a phase transformation of the N–C bonding structures from a graphitic phase where nitrogen substitutes carbon to a pyridinic phase where nitrogen loses one of its bonding arms, with a critical energy Eck = 100 eV that separates the two phases. The N2+-induced changes in the π-band with varying Ek indicate an n-doping effect in the graphitic phase for Ek Eck. We further show that one may control the electron charge density of graphene by two orders of magnitude by varying Ek of N2+ ions within the energy range adopted. Our DFT-based band calculations reproduce the distinct doping effects observed in the π-band of the N2+-doped graphene and provide an orbital origin of the different doping types. We thus demonstrate that the doping type and electron number density in the N2+ ion-doped SLG can be artificially fine-controlled by adjusting the kinetic energy of incoming N2+ ions.

Band and bonding characteristics of N2+ ion-doped graphene

For industrial high-purity hydrogen production, it is essential to develop low-cost, earth-abundant, highly- efficient, and stable electrocatalysts which deliver high current density (j) at low overpotential ( η ) for oxygen evolution reaction (OER). Herein, we report an active mesoporous Ni 2 P @ FePO x H y pre-electrocatalyst, which delivers high j = 1 A cm (cid:0) 2 at η = 360 mV in 1 M KOH with long-term durability (12 days), fulfilling all the desirable commercial criteria for OER. The electrocatalyst shows abundant interfaces between crystalline metal phosphide and amorphous phosphorus-doped metal-oxide, improving charge transfer capability and providing access to rich electroactive sites. Combined with an excellent non-noble metal-based HER catalyst, we achieve commercially required j = 500/1000 mA cm (cid:0) 2 at 1.65/1.715 V for full water-splitting with excellent stability in highly corrosive alkaline environment (30% KOH). The alkaline-anion-exchange-membrane water-electrolyzer (AAEMWE) fabricated for commercial viability exhibits high j of 1 A cm (cid:0) 2 at 1.84 V with long-term durability as an economical hydrogen production method, outperforming the state-of-the-art Pt/C – IrO 2 catalyst.

Crystalline-amorphous interface of mesoporous Ni 2 P @ FePO x H y for oxygen evolution at high current density in alkaline-anion-exchange-membrane water-electrolyzer Applied Catalysis B: Environmental

Suppressed β-Hydride Elimination in Palladium-Catalyzed Cascade Cyclization—Coupling Reactions: An Efficient Synthesis of 3-Arylmethylpyrrolidines.

Erratum: First-principles study of the adsorption of C 2 H 2 and C 2 H 4 on Si(001) [Phys. Rev. B 63, 073306 (2001)]

During growth of two-dimensional (2D) materials, abrupt growth of multilayers is practically unavoidable even in the case of well-controlled growth. In epitaxial growth of a quintuple-layered $${{\rm{Bi}}}_{2}{{\rm{Se}}}_{3}$$ film, we observe that the multilayer growth pattern deduced from in situ x-ray diffraction implies nontrivial interlayer diffusion process. Here we find that an intriguing diffusion process occurs at step edges where a slowly downward-diffusing Se adatom having a high step-edge barrier interacts with a Bi adatom pre-existing at step edges. The Se–Bi interaction lowers the high step-edge barrier of Se adatoms. This drastic reduction of the overall step-edge barrier and hence increased interlayer diffusion modifies the overall growth significantly. Thus, a step-edge barrier reduction mechanism assisted by hetero adatom–adatom interaction could be fairly general in multilayer growth of 2D heteroatomic materials.

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Kwang S. Kim

Papers

Band and bonding characteristics of N2+ ion-doped graphene

Crystalline-amorphous interface of mesoporous Ni 2 P @ FePO x H y for oxygen evolution at high current density in alkaline-anion-exchange-membrane water-electrolyzer Applied Catalysis B: Environmental

Suppressed β-Hydride Elimination in Palladium-Catalyzed Cascade Cyclization—Coupling Reactions: An Efficient Synthesis of 3-Arylmethylpyrrolidines.

Erratum: First-principles study of the adsorption of C 2 H 2 and C 2 H 4 on Si(001) [Phys. Rev. B 63, 073306 (2001)]

Signature of multilayer growth of 2D layered Bi2Se3 through heteroatom-assisted step-edge barrier reduction