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.

/pdf/quantum-espresso-a-modular-and-open-source-software-project-4t6vlupbeh.pdf

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

In perovskite solar cells, the interfaces between the perovskite and charge-transporting layers contain high concentrations of defects (about 100 times that within the perovskite layer), specifically, deep-level defects, which substantially reduce the power conversion efficiency of the devices1–3. Recent efforts to reduce these interfacial defects have focused mainly on surface passivation4–6. However, passivating the perovskite surface that interfaces with the electron-transporting layer is difficult, because the surface-treatment agents on the electron-transporting layer may dissolve while coating the perovskite thin film. Alternatively, interfacial defects may not be a concern if a coherent interface could be formed between the electron-transporting and perovskite layers. Here we report the formation of an interlayer between a SnO2 electron-transporting layer and a halide perovskite light-absorbing layer, achieved by coupling Cl-bonded SnO2 with a Cl-containing perovskite precursor. This interlayer has atomically coherent features, which enhance charge extraction and transport from the perovskite layer, and fewer interfacial defects. The existence of such a coherent interlayer allowed us to fabricate perovskite solar cells with a power conversion efficiency of 25.8 per cent (certified 25.5 per cent)under standard illumination. Furthermore, unencapsulated devices maintained about 90 per cent of their initial efficiency even after continuous light exposure for 500 hours. Our findings provide guidelines for designing defect-minimizing interfaces between metal halide perovskites and electron-transporting layers. An atomically coherent interlayer between the electron-transporting and perovskite layers in perovskite solar cells enhances charge extraction and transport from the perovskite, enabling high power conversion efficiency.

Perovskite solar cells with atomically coherent interlayers on SnO2 electrodes.

We report variation of the work function for single and bilayer graphene devices measured by scanning Kelvin probe microscopy (SKPM). By use of the electric field effect, the work function of graphene can be adjusted as the gate voltage tunes the Fermi level across the charge neutrality point. Upon biasing the device, the surface potential map obtained by SKPM provides a reliable way to measure the contact resistance of individual electrodes contacting graphene.

/pdf/tuning-the-graphene-work-function-by-electric-field-effect-4xp4sk2swu.pdf

Tuning the graphene work function by electric field effect.

We report variation of the work function for single and bi-layer graphene devices measured by scanning Kelvin probe microscopy (SKPM). Using the electric field effect, the work function of graphene can be adjusted as the gate voltage tunes the Fermi level across the charge neutrality point. Upon biasing the device, the surface potential map obtained by SKPM provides a reliable way to measure the contact resistance of individual electrodes contacting graphene.

Tuning the graphene work function by electric field effect

Computing Technologies, Theories, and Algorithms. The Making of 40 Years and More of Theoretical and Computational. A Dynamical, Time-Dependent View of Molecular Theory. Computation of Non-covalent Binding. Electrodynamics in Computational Chemistry. Variational Transition State. Attempting to Simulate Large Molecular Systems. The Beginnings of Coupled Cluster Theory: An Eyewitness Account. Controlling Quantum Phenomena with Photonic Reagents. First-Principles Calculations of Anharmonic Vibrational Spectroscopy of Large Molecules. Finding Minima, Transition States, and Following Reaction Pathways on Ab Initio Potential Energy Surfaces. Progress in the Quantum Description of Vibrational Motion of Polyatomic Molecules. Toward Accurate Computations in Photobiology. The Nature of the Chemical Bond in the Light of an Energy Decomposition Analysis. Superoperator Many-body Theory of Molecular Currents: Non-equilibrium Green Functions in Real Time. Role of Computational Chemistry in the Theory of Unimolecular Reaction Rates. Molecular Dynamics: An Account of its Evolution. Equations of Motion (EOM) Methods for Computing Electron Affinities and Ionization Potentials. Multireference Coupled Cluster Method Based on the Brillouin-Wigner Perturbation Theory. Electronic Structure: The Momentum Perspective. Recent Advances in ab initio, DFT, and Relativistic Electronic Structure Theory . Semiempirical Quantum-Chemical Methods in Computational Chemistry. Size-consistent State-specific Multi-reference Methods: A Survey of Some Recent Developments. The Valence Bond Diagram Approach - A Paradigm for Chemical Reactivity. Development of Approximate Exchange-Correlation Functionals. Multiconfigurational Quantum Chemistry. Concepts of Perturbation, Orbital interaction, Orbital Mixing and Orbital Occupation. G2, G3 and Associated Quantum Chemical Models for Accurate Theoretical Thermochemistry. Factors that Affect Conductance at the Molecular Level. The CH O Hydrogen Bond. A Historical Account. Ab Initio and DFT Calculations on the Cope Rearrangement, a Reaction with a Chameleonic Transition State. High-Temperature Quantum Chemical Molecular Dynamics Simulations of Carbon Nanostructure Self-Assembly Processes. Computational Chemistry of Isomeric Fullerenes and Endofullerenes. On the importance of Many-Body Forces in Clusters and Condensed Phase. Clusters to Functional Molecules, Nanomaterials, and Molecular Devices: Theoretical Exploration. Monte Carlo Simulations of the Finite Temperature Properties of (H2O)6. Computational Quantum Chemistry on Polymer Chains: Aspects of the Last Half Century. Forty Years of Ab Initio Calculations on Intermolecular. Applied Density Functional Theory and the deMon Codes 1964 to 2004. SAC-CI Method Applied to Molecular Spectroscopy. Forty Years of Fenske-Hall Molecular Orbital Theory. Advances in Electronic Structure Theory: GAMESS a Decade Later. How and Why Coupled-Cluster Theory Became the Preeminent Method in Ab initio Quantum Chemistry.

Kwang S. Kim

Papers

Perovskite solar cells with atomically coherent interlayers on SnO2 electrodes.

Tuning the graphene work function by electric field effect.

Tuning the graphene work function by electric field effect

Theory and applications of computational chemistry : the first forty years

Molecular Clusters of π-Systems: Theoretical Studies of Structures, Spectra, and Origin of Interaction Energies