7,090 research outputs found
Symmetry-protected flatband condition for Hamiltonians with local symmetry
We derive symmetry-based conditions for tight-binding Hamiltonians with
flatbands to have compact localized eigenstates occupying a single unit cell.
The conditions are based on unitary operators commuting with the Hamiltonian
and associated with local symmetries that guarantee compact localized states
and a flatband. We illustrate the conditions for compact localized states and
flatbands with simple Hamiltonians with given symmetries. We also apply these
results to general cases such as the Hamiltonian with long-range hoppings and
higher-dimensional Hamiltonian.Comment: 7 pages, 2 figure
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Korean language journalThe purpose of this study was to examine for the deference of leisure activities attitude compared with Korean and America university students' characteristics of leisure activities attitude in subcategory factors of leisure activities attitude include recognitive attitude, definitive attitude, behavioral attitude. 241 M,H,Y university students in Korea and 143 North Carolina N university students are responded survey for this study from 2007, May to August. The collected data based of survey are analyzed through frequency analysis, t- test, one-way ANOV A analysis by SPSS WIN ver 12.0. The result is following : First, there were statistical difference of leisure activities attitude in behavioral attitude between Korean students and America students. Second, there were statistical difference shows difference grade sector, own major, personal expenses in recognitive attitude. Third, the statistical difference shows grade sector, personal expenses in definitive attitude. Forth, the statistical difference shows grade sector, own major and personal expenses in of behavioral attitude
Performance evaluation on GNSS, wheel speed sensor, yaw rate sensor, and gravity sensor integrated positioning algorithm for automotive navigation system
The Global Navigation Satellite System (GNSS) positioning technique is widely used for the automotive navigation system since it can provide the stable and accurate position and velocity in the most road environments at an affordable price. However, the performance of GNSS positioning technique is degraded in certain areas, where GNSS signals are blocked by buildings and tunnel. To overcome this problem, the GNSS positioning technique should be integrated with dead reckoning (DR) sensors such as accelerometer, gyroscope, and odometer. Recently, the most passenger cars are equipped with the Advanced Driver Assistance System (ADAS) based on numerous sensors to improve safety and convenience in driving. Among sensors for the ADAS, vehicle dynamic sensors such as wheel speed sensor (WSS), yaw rate sensor (YRS), gravity sensor (GS) can be used for the DR algorithm since those sensors measure vehicle’s motions. Therefore, this paper evaluates the vehicle positioning algorithm that integrate the GNSS with a three-dimensional dead reckoning based on WSS, YRS, and GS. The vehicle positioning algorithm is implemented through the extended Kalman filter of a loosely-coupled mode. Performance was evaluated through tests carried out in real driving trajectory including various GNSS signals reception environments. It is found that the proposed algorithm can be an alternative solution to compensate the limitation of the GNSS positioning technique, without the use of a low-cost inertial measurement unit
THE EFFECT OF SHOULDER MOBILITY ON AGONIST AND SYNERGIST DURING SHOULDER PRESS
The purpose of this study was to investigate the effect of shoulder mobility score on agonist and synergist muscle activation during shoulder press and to provide an underpinning fundamental to optimize the training effect while reducing the risk of injuries when instructing training in the field. The participants were divided to two different groups according to individual shoulder mobility score which is part of the Functional Movement Screen (FMS). There were five participants in the score of 3 group (upper group) and six included in the group with the score of less than 3 (lower group). The results of this study revealed that the shoulder mobility score showed a negative correlation with the ratio of the left and right latissimus dorsi/anterior deltoid muscle activation in the concentric contraction phase (
Phytosynthesis of Silver and Gold Nanoparticles Using the Hot Water Extract of Mixed Woodchip Powder and Their Antibacterial Efficacy
This study investigates the phytosynthesis, characterization, and antibacterial efficacy of silver and gold nanoparticles (NPs) produced using the hot water extract of mixed woodchip powder. The woodchip extract (WCE) was successfully used as both a reducing and stabilizing agent for the phytosynthesis of both crystalline metal NPs. The effects of different physicochemical factors affecting the formation of the metal NPs including reaction pH, concentration of the precursor metal salts, amount of WCE, and external energy input were evaluated. The characterization of the metal NPs was performed by transmission electron microscopy, selected area electron diffraction (SAED), energy dispersive X-ray (EDX) spectroscopy, and X-ray diffraction (XRD) pattern analysis. In addition, the antibacterial efficacy of the phytosynthesized NPs was measured. The AgNPs showed clear antibacterial activity against four representative bacterial strains. However, the AuNPs did not exhibit bactericidal activity, probably due to their surface modifications and relatively large size. These results suggest that the phytosynthesis of the metal NPs using WCE is highly efficient, and its convenience makes it suitable for use in large-scale production
N-(Pyridin-2-ylmethyl)pyridin-2-amine
The title compound, C11H11N3, crystallizes with two molecules (A and B) in the asymmetric unit. The geometries of both molecules are very similar, with the exception of the torsion angles of the inter-ring chains; the values for C—N—C—C are 67.4 (5) and −69.3 (5)° for molecules A and B, respectively. The dihedral angles between the pyridyl ring planes are 84.0 (2) and 83.2 (2)° for molecules A and B, respectively. In the crystal, weak intermolecular N—H⋯N hydrogen bonds and C—H⋯π interactions contribute to the stabilization of the packing
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