Magnetic Order in Heisenberg Models on Non-Bravais Lattice: Popov-Fedotov Functional Method

We study magnetic properties of ordered phase in Heisenberg model on a non-Bravais lattice by means of Popov - Fedotov trick, which takes into account a rigorous constraint of a single occupancy. We derive magnetization and free energy using sadle point approximation in the functional integral formalism. We illustrate the application of the Popov -- Fedotov approach to the Heisenberg antiferromagnet on a honeycomb lattice

Supersolids of Hard Core - Bosons on a Triangular Lattice

We study the boson model on a triangular lattice interacting only via on-site hardcore repulsion by mapping to a system of spins $(S = 1/2)$. We investigate the supersolid phase of the systems which is a state matter displaying both diagonal long- range (solid) order as well as off-diagonal long-range (superfluidity) by utilizing a semionic representation for the spin-XXZ model. We show that the supersolid order is stable in the mean-field theory for a broad region of parameters. The inclusion of spin wave corrections modifies this picture, but the supersolid phase is still quite robust on the triangular lattices

Erratum: Mott Transition in the Mass Imbalanced Ionic Hubbard Model at Half Filling

Erratum: Mott Transition in the Mass Imbalanced Ionic Hubbard Model at Half Filling[Nguyen Thi Hai Yen, Le Duc Anh, Hoang Anh Tuan, Nguyen Toan Thang and Tran Thi Thu Trang, Communications in Physics, Vol. 29, No. 3SI (2019), pp. 305-312]This paper was published on 22 October 2019 with an omission in the text of the author’s list. The author list should read asNGUYEN THI HAI YEN$^1$, LE DUC ANH$^2$, HOANG ANH TUAN$^{1,3,\dagger}$, NGUYEN TOAN THANG$^1$, TRAN THI THU TRANG$^4$ AND NGUYEN THI HUONG$^5$$^1$Institute of Physics, Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam $^2$Hanoi National University of Education, Hanoi, Vietnam $^3$Graduate University of Science and Technology, VAST, Hanoi, Vietnam $^4$Ha Long University, Quang Ninh, Vietnam $^5$Thuy Loi University, Hanoi, Vietnam$^{\dagger}$E-mail: [email protected] author’s list has been corrected as of 29 November 2019. The author’s list has been corrected in the electronic version of the journal

Synergic Effect of CaI and LiI on Ionic Conductivity of Solution-Based Synthesized Li7P3S11 Solid Electrolyte

Li7P3S11 doped with CaX2 (X = Cl, Br, I) and LiI solid electrolytes were successfully prepared by liquid-phase synthesis using acetonitrile as the reaction medium. Their structure was investigated using XRD, Raman spectroscopy and SEM-EDS. The data obtained from complex impedance spectroscopy was analyzed to study the ionic conductivity and relaxation dynamics in the prepared samples. The XRD results suggested that a part of CaX2 and LiI incorporated into the structure of Li7P3S11, while the remaining part existed at the grain boundary of the Li7P3S11 particle. The Raman peak positions of PS43- and P2S74- ions in samples 90Li7P3S11-5CaI2 and 90Li7P3S11-5CaI2-5LiI had shifted as compared to the Li7P3S11 sample, showing that CaI2 addition affected the vibration of PS43- and P2S74- ions. EDS results indicated that CaI2 and LiI were well dispersed in the prepared powder sample. The ionic conductivity at 25 °C of sample 90Li7P3S11-5CaI2-5LiI reached a very high value of 3.1 mS cm-1 due to the improvement of Li-ion movement at the grain boundary and structural improvement upon CaI2 and LiI doping. This study encouraged the application of Li7P3S11 in all-solid-state Li-ion batteries

A Novel Parallel Hardware Architecture for Inter Motion Estimation in HEVC

High Efficiency Video Coding (HEVC) standard, generated by ITU, can provide compression ratio twice more than current H.264/ MPEG-4. To date, only a few hardware have been implementated for Integer Motion Estimation (IME) to date. In this paper, a parallel hardware architecture for IME in HEVC encoder is proposed. This design uses Rot-WDiamond (RWD) algorithm to reduce computational load and parallelism to improve processing speed. Therefore, this design can reach 4K (4096×2160) video in real time at 60 frames per second (fps) and achieve the frequency of 125MHz

Probabilistic Schema Covering

Schema covering is the process of representing large and complex schemas by easily comprehensible common objects. This task is done by identifying a set of common concepts from a repository called concept repository and generating a cover to describe the schema by the concepts. Traditional schema covering approach has two shortcomings: it does not model the uncertainty in the covering process, and it requires user to state an ambiguity constraint which is hard to define. We remedy this problem by incorporating probabilistic model into schema covering to generate probabilistic schema cover. The integrated probabilities not only enhance the coverage of cover results but also eliminate the need of defining the ambiguity parameter. Both probabilistic schema covering and traditional schema covering run on top of a concept repository. Experiments on real-datasets show the competitive performance of our approach

Bootstrapping Uncertainty in Schema Covering

Schema covering is the process of representing large and complex schemas by easily comprehensible common objects. This task is done by identifying a set of common concepts from a repository called concept repository and generating a cover to describe the schema by the concepts. Traditional schema covering approach has two shortcomings: it does not model the uncertainty in the covering process, and it requires user to state an ambiguity constraint which is hard to define. We remedy this problem by incorporating probabilistic model into schema covering to generate probabilistic schema cover. The integrated probabilities not only enhance the coverage of cover results but also eliminate the need of defining the ambiguity parameter. Experiments on real-datasets show the competitive performance of our approach

NICKEL-BASED MULTIWALLED CARBON NANOTUBE COMPOSITE COATINGS

Carbon nanotubes (CNTs) have been widely known as nanomaterials with excellent mechanical properties. Previous studies reported that the tensile strength of multi-walled carbon nanotubes (MWCNTs) was up to 63 GPa and single-walled carbon nanotubes (SWCNTs) could reach 150 GPa while the highest tensile strength of the steel was found to be about 1.8 GPa. SWCNTs could have Young’s modulus up to 1000 GPa that was much greater than the value of 209 GPa of steel. Therefore, there is a great potential to utilize CNTs as reinforced materials for composites in general and Ni electrodeposition coating in particular to improve hardness, durability, corrosion, and other physical and mechanical properties. This paper presents results of preparing and examining characteristics of the Nickel electrodeposition coatings containing MWCNTs (Ni-MWCNTs). The Ni-MWCNTs composite coatings deposited on a steel plate with the area of 0.4 dm2 using bipolar pulses at 470 Hz and 50oC in a 5-liter bath. Amount of CNTs varying from 1 g/l to 3 g/l was dispersed into the solution by using surfactants and ultrasonic vibration. CNTs used in the study was MWCNTs diameters in the range from 20 to 90 nanometers and few micrometers in length. The SEM, EDS, hardness and adhesion tests were conducted to analyze the properties of the electrodeposition coatings. The obtained results indicated that the hardness and adhesion of the Ni-CNTs coating were 1.5 and 1.46 times, respectively, higher than those of the Ni coating. In addition, adhesion of the Ni-CNTs coating was significantly improved