Gyrotropic linear and nonlinear motions of a magnetic vortex in soft magnetic nanodots

The authors investigated the gyrotropic linear and nonlinear motions of a magnetic vortex in soft magnetic cylindrical nanodots under in-plane oscillating magnetic fields of different frequencies and amplitudes, by employing both micromagnetic simulations and the numerical solutions of Thiele's equation of motion [Phys. Rev. Lett. 30, 230 (1973)]. Not only noncircular elliptical vortex-core orbital trajectories in the linear regime but also complex trajectories including stadiumlike shape in the nonlinear regime were observed from the micromagnetic simulations and were in excellent agreement with the numerical solutions of the analytical equations of motion. It was verified that the numerical solutions of Thiele's equation are promisingly applicable in order to predict and describe well such complex vortex gyrotropic linear and nonlinear motions in both the initial transient and later steady states. These results enrich the fundamental understanding of the linear and nonlinear motions of vortices in confined magnetic elements in response to oscillating driving forces.open352

Hallyu and the Traditional Cultural Genes of Korea

Since the year 2000, South Korea has been the propagator of the Hallyu (Korean Wave) that has spread across the world, demonstrating the country’s cultural potential. The subject of Hallyu can be approached from several perspectives, first by identifying its origins, current status, and trends by genre; by looking at its effects and the measures that can sustain the Hallyu phenomenon; and also by examining Hallyu trends by country. This paper analyzes Korea’s traditional cultural genes that affected the creation and spread of Hallyu from a humanistic point of view. The three factors for this analysis are: i) community and courtesy, ii) dynamics and excitement, and iii) intuition and harmony. This study is expected to deepen the understanding of the relation between Hallyu and Korean traditional cultural resources

Reliability Analysis on Flexural Behavior of FRP Bridge Decks

Design codes for the design of FRP bridge decks shall be established to promote the use of such innovative materials. For the purpose of preparing code provisions, reliability analyses were conducted to evaluate proper levels of safety and serviceability. Based on the results, several guidelines on design codes are suggested

Spin-wave interference

Spin-wave interference is demonstrated in the micromagnetic modeling of a specially designed geometry made of variously shaped magnetic thin-film waveguides. When spin waves are diffracted through two separate openings, corresponding to the two pinholes in the second screen of Young's apparatus, they interfere constructively or destructively in a magnetic medium, thereby showing distinct interference patterns. Furthermore, the radiation, propagation, transmission, and dispersion behaviors of spin waves as well as the filtering of their lower frequencies are investigated in the present modeling study. These results directly confirm not only the wave characteristics of spin waves traveling at ultrafast speeds in variously shaped magnetic waveguides but also their interference effect, that is similar to that observed in well-known Young's double slit experiment with light.open312

Molecular identification of Reesa vespulae (Milliron) (Coleoptera: Dermestidae), a newly recorded species from Korea

AbstractA museum pest belonging to the family Dermestidae was found in the Museum of Sunchon National University, Sunchon, Korea and identified using its morphological characteristics and a DNA-based analysis of the mitochondrial cytochrome c oxidase I (COI) gene. This marks the first recorded appearance of this pest, which is identified as Reesa vespulae (Milliron), in the Korean Peninsula. We provide the details of the morphological diagnosis with the habitus of its adult and larva and its COI barcode data, and introduce historical data about its invasion around the world

Two-point discrimination values vary depending on test site, sex and test modality in the orofacial region: a preliminary study

The two-point discrimination (TPD) test is one of the most commonly used neurosensory tests to assess mechanoperception in the clinical settings. While there have been numerous studies of functional sensibility of the hand using TPD test, there have been relatively not enough reports on TPD in the orofacial region. Objective The aims of the present study were to determine the normal values of TPD in the six trigeminal sites (the forehead, cheek, mentum, upper lip, lower lip, and the tongue tip) and to investigate the effect of the site, sex, and test modality on the TPD perception. Material and Methods Forty healthy volunteers consisting of age-matched men (20) and women (20) with a mean age of 27.1 years were recruited. One examiner performed the TPD test using a simple hand-operated device, i.e., by drawing compass with a blunt or sharp-pointed tip. The static TPD with a blunt-pointed tip (STPDB), moving TPD with a blunt-pointed tip (MTPDB), and static TPD with a sharp-pointed tip (STPDS) were measured. The predictors were the site, sex, and test modality, and the outcome variable was the TPD value. Three-way ANOVA was used for statistics. Results The analysis showed a significant effect of the site, sex and test modality on the TPD values. Significant differences between the test sites were observed with the descending order from the forehead and cheek>;mentum>;upper lip and lower lip>;tongue tip and index finger. Women showed lower TPD values than those of men. The STPDS measurements were consistently lower than those of the STPDB and MTPDB. Conclusions The normal values of TPD in this study suggest that the cheek and forehead were less sensitive than other regions evaluated and women were more sensitive than men. The STPDS was the most sensitive test modality

Remarkable enhancement of domain-wall velocity in magnetic nanostripes

Remarkable reductions in the velocity of magnetic-field (or electric current)-driven domain-wall (DW) motions in ferromagnetic nanostripes have typically been observed under magnetic fields stronger than the Walker threshold field [N. L. Schryer and L. R. Walker, J. Appl. Phys. 45, 5406 (1974)]. This velocity breakdown is known to be associated with an oscillatory dynamic transformation between transverse- and antivortex (or vortex)-type DWs during their propagations. The authors propose, as the result of numerical calculations, a simple means to suppress the velocity breakdown and rather enhance the DW velocities, using a magnetic underlayer of strong perpendicular magnetic anisotropy. This underlayer plays a crucial role in preventing the nucleation of antivortex (or vortex)-type DWs at the edges of nanostripes, in the process of periodic dynamic transformations from the transverse into antivortex- or vortex-type wall. The present study not only offers a promising means of the speedup of DW propagations to levels required for their technological application to ultrafast information-storage or logic devices, but also provides insight into its underlying mechanism.open383

Dynamic Origin of Vortex Core Switching in Soft Magnetic Nanodots

The magnetic vortex with the in-plane curling magnetization and the out-of-plane magnetization at the core is a unique ground state in nanoscale magnetic elements. This kind of magnetic vortex can be used as a memory unit for information storage, through its downward or upward core-orientation and, thus, controllable core switching deserves some special attention. Our analytical and micromagnetic calculations reveal that the origin of the vortex core reversal is a gyrotropic field. This field is induced by vortex dynamic motion and is proportional to the velocity of the moving vortex. Our calculations elucidate the physical origin of the vortex core dynamic reversal and offer a key to effective manipulation of the vortex-core orientation.Comment: 17 pages and 3 figure