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

Water Splitting: One-Step Synthesis of CoS-Doped β-Co(OH)2@Amorphous MoS2+x Hybrid Catalyst Grown on Nickel Foam for High-Performance Electrochemical Overall Water Splitting (Adv. Funct. Mater. 41/2016)

A Three-Dimensional Active Site Model of Carboxypeptidase A

Longitudinal magnetoresistivity ${\ensuremath{\rho}}_{xx}(B)$ and Hall resistivity ${\ensuremath{\rho}}_{xy}(B)$ of KMo${}_{6}$O${}_{17}$ single crystals have been measured up to 60 T in a pulse magnet. Remarkable and unusual features at characteristic magnetic fields were found in both ${\ensuremath{\rho}}_{xx}(B)$ and ${\ensuremath{\rho}}_{xy}(B)$, which were attributed to Fermi surface reconstructions caused by field-induced density-wave transitions. To understand these transitions in detail, we analyzed ${\ensuremath{\rho}}_{xx}(B)$ and ${\ensuremath{\rho}}_{xy}(B)$ based on a multiband model. This model successfully described the experimental results, revealing that charge carriers are increased significantly at these transitions with increasing magnetic field as a result of the Fermi surface reconstruction. In particular, the charge carriers are increased by two orders of magnitude at ${B}_{\mathrm{osc}}=\ensuremath{\sim}40$ T, above which a quantum oscillation emerges in both ${\ensuremath{\rho}}_{xx}(B)$ and ${\ensuremath{\rho}}_{xy}(B)$. This strongly suggests that the field-induced quantum oscillation is closely related with the induced charge carriers.

Magnetic-field-induced transitions and evolution of magnetotransport properties in quasi-two-dimensional KMo 6 O 17 in the charge-density-wave phase

The results of a combined experimental and theoretical investigation of the molecular structure of p-cyclohexylaniline (pCHA) in the electronic ground and the first electronically excited state are reported. The experimental investigations are performed for the crystalline phase by X-ray diffraction for the first time and related to former gas phase results obtained by time-resolved rotational laser spectroscopy. The theoretical results, from new ab initio calculations at the MP2/6-31+G(d) and CIS/6-31+G(d) level of theory for the electronic ground and excited state, respectively, give an adequate description of the rotational constants as obtained by the gas phase experiments. Thus, a detailed comparison of the ab initio structure for the ground state with the X-ray structure is performed in order to ascertain differences in the molecular geometry between the gas and crystalline phase. In particular, the size of the aromatic and cyclohexyl ring, their mutual orientation, and the conformation of the NH2 g...

Molecular Structure of p-Cyclohexylaniline. Comparison of Results Obtained by X-ray Diffraction with Gas Phase Laser Experiments and ab Initio Calculations

We demonstrate and advocate the use of observable quantities derived from the two-electron reduced density matrix - pair densities, conditional densities, and exchange-correlation holes--as signatures of the type of electron correlation in a chemical bond. The prototype cases of the lowest (1)Σ(u)(+) and (1)Σ(g)(+) states of H(2), which exhibit large variation in types of bonding, ranging from strongly ionic to covalent, are discussed. Both the excited (1)Σ(g)(+) and (1)Σ(u)(+) states have been interpreted as essentially consisting of (natural) orbital configurations with an inner electron in a contracted 1sσ(g) orbital and an outer electron in a diffuse (united atom type, Rydberg) orbital. We show that nevertheless totally different correlation behavior is encountered in various states when comparing them at a common internuclear distance. Also when following one state along the internuclear distance coordinate, strong variation in correlation behavior is observed, as expected. Switches between ionic to covalent character of a state occur till very large distances (40 bohrs for states approaching the 1s3[script-l] asymptotic limit, and 282 bohrs for states approaching the 1s4[script-l] limit).

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Kwang S. Kim

Papers

Water Splitting: One-Step Synthesis of CoS-Doped β-Co(OH)2@Amorphous MoS2+x Hybrid Catalyst Grown on Nickel Foam for High-Performance Electrochemical Overall Water Splitting (Adv. Funct. Mater. 41/2016)

A Three-Dimensional Active Site Model of Carboxypeptidase A

Magnetic-field-induced transitions and evolution of magnetotransport properties in quasi-two-dimensional KMo 6 O 17 in the charge-density-wave phase

Molecular Structure of p-Cyclohexylaniline. Comparison of Results Obtained by X-ray Diffraction with Gas Phase Laser Experiments and ab Initio Calculations

Electron pair density in the lowest 1Σ(u)(+) and 1Σ(g)(+) states of H2.