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

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?

日本物理学会誌及びJournal of the Physical Society of Japanの月刊について

Materials research has driven the development of modern nano-electronic devices. In particular, research in magnetic thin films has revolutionized the development of spintronic devices1,2 because identifying new magnetic materials is key to better device performance and design. Van der Waals crystals retain their chemical stability and structural integrity down to the monolayer and, being atomically thin, are readily tuned by various kinds of gate modulation3,4. Recent experiments have demonstrated that it is possible to obtain two-dimensional ferromagnetic order in insulating Cr2Ge2Te6 (ref. 5) and CrI3 (ref. 6) at low temperatures. Here we develop a device fabrication technique and isolate monolayers from the layered metallic magnet Fe3GeTe2 to study magnetotransport. We find that the itinerant ferromagnetism persists in Fe3GeTe2 down to the monolayer with an out-of-plane magnetocrystalline anisotropy. The ferromagnetic transition temperature, Tc, is suppressed relative to the bulk Tc of 205 kelvin in pristine Fe3GeTe2 thin flakes. An ionic gate, however, raises Tc to room temperature, much higher than the bulk Tc. The gate-tunable room-temperature ferromagnetism in two-dimensional Fe3GeTe2 opens up opportunities for potential voltage-controlled magnetoelectronics7-11 based on atomically thin van der Waals crystals.

Gate-tunable Room-temperature Ferromagnetism in Two-dimensional Fe 3 GeTe 2

https://shell.cas.usf.edu/~phanm//PMS.pdf

Giant magnetoimpedance materials: Fundamentals and applications

Researches about infrastructure and applications of next generation Internet is one of the most comprehensive research fields in recent years, IP over WDM is envisioned as the best candidate for next generation Internet. Generalized Multi-Protocol Label Switching (GMPLS) was proposed as an excellent control plane technology for the 
integration of IP and WDM, which can achieve the on-demand provisioning and management of network resources. And optical burst switching (OBS) is considered as a promising switch paradigm for next generation Internet, which can not only provide statistical multiplexing of network bandwidth resources, but also circumvent the bottleneck of electronic switching effectively. Therefore, how to integrate GMPLS into OBS network and use GMPLS to improve performances of OBS networks becomes an important research direction and have received comprehensive concerns from many research institutions and organizations. This article proposes a new kind of OBS network namely GMPLS-based OBS network, describes its general framework and some work mechanisms, and gives node functional modules 
and the control plane software components. Some issues related to network management also are discussed.

A general framework for GMPLS-based OBS networks

In this paper, the fabrication of a highly orientated Bi2Fe4O9 (BFO) photoelectrode in the presence of two-dimensional (2D) graphene oxide (GO) was reported. It was found that the GO can be used as a template for controlling the growth of BFO, and the nanoplate composites of BFO/reduced graphene oxide (RGO) with a high orientation can be fabricated. The thickness of the nanoplates became thinner as the ratio of GO increased. As a result, the ferroelectric spontaneous polarization unit arranges itself in the space in a periodic manner, leading to the formation of a polarization field along a special direction. Therefore, the created built-in electric field of the nanoplate composites of BFO/RGO is improved upon the increase of the amount of RGO. As expected, carrier separation is enhanced by the built-in electric field, therefore substantially enhancing the photoelectrochemical (PEC) activity of water splitting compared to pure BFO under the irradiation of visible-light.

Spontaneous polarization enhanced bismuth ferrate photoelectrode: fabrication and boosted photoelectrochemical water splitting property

Since the antenna interval of service antenna array for communication is greater than half a wavelength and does not satisfy the spatial sampling theorem, it is a great challenge to leverage service antenna array for channel state information-based signal parameters estimation, such as time-of-flight (TOF) and angle-of-arrival (AOA) estimation. To overcome this challenge, this letter proposes a diagonal spatial mapping-based multiple signal classification (MUSIC) and matching pursuit (MP) fusion (DSM-MMF) algorithm. First, a new virtual linear array is constructed by mapping the service antenna array on the diagonal of the plane array. Second, a fusion AOA and TOF estimation for the signal mapped on the virtual linear array is realized by utilizing the MUSIC and MP fusion algorithm. Third, through the unique geometric relationship between the virtual linear array and the service antenna array, the AOA and TOF can be obtained. Finally, experimental results show that the DSM-MMF’s median localization error is about four decimeters.

Service Antenna Array-Based Parameter Estimation for Decimeter Level Indoor Localization

We report electrical and thermal transport properties of single crystalline kagome metals $A$Ti$_3$Bi$_5$ ($A$ = Rb, Cs). Different from the structural similar kagome superconductors $A$V$_3$Sb$_5$, no charge density wave instabilities are found in $A$Ti$_3$Bi$_5$. At low temperatures below 5 K, signatures of superconductivity appear in $A$Ti$_3$Bi$_5$ as seen in magnetization measurements. However, bulk superconductivity is not evidenced by specific heat results. Similar to $A$V$_3$Sb$_5$, $A$Ti$_3$Bi$_5$ show nonlinear magnetic field dependence of the Hall effect below about 70 K, pointing to a multiband nature. Unlike $A$V$_3$Sb$_5$ in which phonons and electron-phonon coupling play important roles in thermal transport, the thermal conductivity in $A$Ti$_3$Bi$_5$ is dominated by electronic contributions. Moreover, our calculated electronic structure suggests that van Hove singularities are sitting well above the Fermi energy. Compared with $A$V$_3$Sb$_5$, the absence of charge orders in $A$Ti$_3$Bi$_5$ is closely associated with minor contributions from electron-phonon coupling and/or van Hove singularities.

Electrical and thermal transport properties of kagome metals $A$Ti$_3$Bi$_5$ ($A$ = Rb, Cs)

The aim of this study was to develop a method to detect a point mutation in the ribosomal S12 protein (rpsL) gene in streptomycin-resistant strains of Xanthomonas oryzae pv. oryzicola and X. oryzae pv. oryzae. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was developed to detect a point mutation in codon 43 of the rpsL gene in X. oryzae pv. oryzicola and X. oryzae pv. oryzae. The 304-bp PCR product from the rpsL gene was digested by MboII to form two fragments (201 and 103 bp) if there was a mutation at codon 43, or three fragments (146, 103, and 55 bp) if there was no mutation. Compared with the results from nucleotide sequencing, the PCR-RFLP method was accurate in detecting the point mutation at codon 43 of the rpsL gene in streptomycin-resistant strains of X. oryzae pv. oryzicola and X. oryzae pv. oryzae. These results indicate that the PCR-RFLP is a simple, rapid and reliable method for detecting the point mutation at codon 43 of the rpsL gene.

/pdf/detection-of-a-mutation-at-codon-43-of-the-rpsl-gene-in-5c201hgtdv.pdf

Xiaolong Yang

Papers

A general framework for GMPLS-based OBS networks

Spontaneous polarization enhanced bismuth ferrate photoelectrode: fabrication and boosted photoelectrochemical water splitting property

Service Antenna Array-Based Parameter Estimation for Decimeter Level Indoor Localization

Electrical and thermal transport properties of kagome metals $A$Ti$_3$Bi$_5$ ($A$ = Rb, Cs)

Detection of a mutation at codon 43 of the rpsL gene in Xanthomonas oryzae pv. oryzicola and X. oryzae pv. oryzae by PCR-RFLP.