1,557 research outputs found

    Electron and phonon band-structure calculations for the antipolar SrPt3_{3}P antiperovskite superconductor: Evidence of low-energy two-dimensional phonons

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    SrPt3P has recently been reported to exhibit superconductivity with Tc = 8.4 K. To explore its superconducting mechanism, we have performed electron and phonon band calculations based on the density functional theory, and found that the superconductivity in SrPt3P is well described by the strong coupling phonon-mediated mechanism. We have demonstrated that superconducting charge carriers come from pd\pi-hybridized bands between Pt and P ions, which couple to low energy (~ 5 meV) phonon modes confined on the ab in-plane. These in-plane phonon modes, which do not break antipolar nature of SrPt3P, enhance both the electron-phonon coupling constant \lambda and the critical temperature Tc. There is no hint of a specific phonon softening feature in the phonon dispersion, and the effect of the spin-orbit coupling on the superconductivity is found to be negligible.Comment: 5 pages, 5 figures, 1 tabl

    COMPARISON OF THE RISK FACTORS OF KOREAN ADOLESCENT SUICIDE RESIDING IN HIGH SUICIDAL REGIONS VERSUS THOSE IN LOW SUICIDAL REGIONS

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    Background: The suicide rate of the youth in South Korea has been increasing, and suicide of the youth still has been the most common cause of death since 2007. We aimed to determine the trends and the regional risk factors of youth suicide in South Korea from 2001 to 2010. Subjects and Methods: We used the data from the National Statistical Office to calculate the standardized suicide rates and various regional data including population census, employment, and labor. To calculate the effect of individual risk factors, we used the data from the fourth Korean Youth Risk Behavior Web-based Survey (KYRBWS-VI). Conditional autoregressive model for regional standardized mortality ratio (SMR) using inter-regional spatial information was fitted. Results: Suicide rates of adolescents aged 12 to 18 was from 3.5 per 100,000 people in 2001 and 5.3 per 100,000 in 2010. There were no significant gender difference in suicide rates, however, the number of suicides among adolescents aged 15-18 accounted for four times than those of adolescents ages 12-14. High proportion of late adolescents, higher number of recipients of national basic livelihood, and higher number of adolescents who treated with depression were related to elevated suicide rate of adolescent. Total sleep time of adolescents and regional unemployment rate were negatively associated with the suicide risk of respective regions. Conclusions: Age distribution, economic status, total sleep time, and the number of adolescent patients with depression were different between those in low and in high adolescent suicidal regions in Korea. Our findings suggest that preferential appliance of adolescent suicide prevention program for regions by considering those factors may be important steps to reduce adolescent suicide in Korea

    System Development of Transmitting Conformal SATCOM Array Antenna Structures(CSAAS)

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    This study presents the development results of Conformal SATCOM Array Antenna Structure(CSAAS) for transmitting. Tile Type antenna with 8x8 antenna element array has been developed instead of reflector antenna. 8x8 tile antennas are arrayed on the curved surface with one directional curvature to simulate aircraft skin configuration. Housing has the grid structure to minimize out-of-plane deformation that affects the antenna performances. Tile antennas are attached to the surfaces between grids. Radome is designed as an A-sandwich type to carry some distributed skin load and glass epoxy material with lowest dielectric constant and loss tangent was used for the best electromagnetic performance. One tile antenna is designed with a separate data control and power connection for vertical and horizontal polarization. The static structural strength of the housing and impact strength of the radome were verified by the analysis and tests. Beam pattern test, beam control test and beam steering test are performed in an anechoic chamber for the transmitting CSAAS. The results of structural and electromagnetic tests showed that the design objects met the goal successfully

    Clinical disease characteristics according to karyotype in Turner syndrome

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    Purpose : Turner syndrome (TS) is a disorder in which various anomalies can be accompanied, especially cardiovascular, renal, thyroid and auditory problems. The aim of this study is to identify the incidence of these disorders in patients with TS according to karyotype. Methods : We reviewed medical records of 90 patients with TS diagnosed by chromosomal analysis in 4 hospitals from Jan 1998 to Dec 2007. We evaluated these cases by prepared protocol of 4 medical problems. Results : The distribution of karyotype was 45,X (47.8%), mosaic pattern (34.4%) and structural aberration group (17.8 %). Renal anomalies, cardiovascular anomalies, thyroid disorders and auditory problems are accompanied in 4.4%, 10.0 %, 11.1% and 5.6%, respectively. 45,X group had renal anomalies (7.0%), cardiovascular anomalies (18.6%), thyroid disorders (9.3%) and auditory problems (11.6%). Mosaic group had renal anomalies (3.2%), thyroid disorders (12.9%), no cardiovascular anomalies and auditory problems. Structural aberration group had cardiovascular anomalies (6.3%), thyroid disorders (12.5%) and no other 2 problems. Patients with 45,X group had a significant higher incidence of cardiovascular anomalies (P=0.025). Conclusion : Our results indicate that there are differences clinically according to karyotype of TS, especially in incidence of cardiovascular anomalies
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