NMR study on the stability of the magnetic ground state in MnCr2{}_2O4{}_4

The canting angles and fluctuation of the magnetic ion spins of spinel oxide MnCr${}_2$O${}_4$ were studied by nuclear magnetic resonance (NMR) at low temperatures, which has a collinear ferrimagnetic order below $T_C$ and a ferrimagnetic spiral order below $T_s < T_C$. Contrary to previous reports, only one spin canting angle of Cr ions was observed. The spin canting angles of Mn and Cr ions in the ferrimagnetic spiral obtained at a liquid-He temperature were 43\,^{\circ} and 110\,^{\circ}, respectively. The nuclear spin-spin relaxation was determined by the Suhl-Nakamura interaction at low temperatures but the relaxation rate $T_2^{-1}$ increases rapidly as the temperature approaches $T_s$. This indicates that the fluctuation of the spiral component becomes faster as the temperature increases but not fast enough to leave an averaged hyperfine field to nuclei in the time scale of nuclear spin precession in the ferrimagnetic phase, which is on the order of $10^{-8}$ s. The spiral volume fraction measured for various temperatures reveals that the collinear and the spiral ferrimagnetic phases are mixed below the transition temperature of the spiral order. The temperature hysteresis in the volume fraction implies that this transition has first-order characteristics.Comment: 13 pages, 5 figure

Implementation Mechanism of the Four-Group Shift System at Yuhan-Kimberly

Research has long reported the difficulty of adopting a new system into an organization. Therefore, we have examined the introduction process of a new system through Yuhan-Kimberlys case for finding the solution. The new system such as the four-group shift of Yuhan-Kimberly is an effective combination of technological skills and HR management skills respecting human beings. It also generates competitive advantages contributing to the formation of lifelong education, decreased safety-related accidents, and increased product quality and productivity. This system allows employees to trust that the company regards its employees as true companions. From the Yuhan-Kimberlys case, we could reveal the secret of the successful introduction of a new system via a mechanism framework.This work was supported by the second stage of the Brain Korea 21 Project in 2007

Tracing the historical origin of Joseon mummies considering the structural similarities between the burial systems of Korean and Chinese dynasties

Joseon mummies have proved to be excellent subjects for scientific research on the health and disease statuses of pre-modern Korean peoples. Despite its academic significance, the origins of the Hoegwakmyo tomb in which the Joseon mummy was discovered have not yet been entirely revealed. Meanwhile, over the past several decades, there have been some reports on mummies and cultural artifacts preserved very well in the tombs of several Chinese dynasties (especially Song, Yuan, Ming and Qing). Although the Chinese tombs were very diverse in structure, we note that some graves among them were structurally very similar to Joseon Hoegwakmyo tombs. Before the Hoegwakmyo tomb in Korea, there were already similar tombs in China, inside which dead persons were mummified like the Joseon mummies. Considering that the Hoegwakmyo tomb of the Joseon Dynasty was established by the influence of the Confucian ideology, the Korean and Chinese mummies might share common cultural origins in history

Realization of giant magnetoelectricity in helimagnets

We show that low field magnetoelectric (ME) properties of helimagnets Ba0.5Sr1.5Zn2(Fe1-xAlx)12O22 can be efficiently tailored by Al-substitution level. As x increases, the critical magnetic field for switching electric polarization is systematically reduced from ~1 T down to ~1 mT, and the ME susceptibility is greatly enhanced to reach a giant value of 2.0 x 10^4 ps/m at an optimum x = 0.08. We find that control of nontrivial orbital moment in the octahedral Fe sites through the Al-substitution is crucial for fine tuning of magnetic anisotropy and obtaining the conspicuously improved ME characteristics

Dirac solitons in optical microresonators

Mode-coupling-induced dispersion has been used to engineer microresonators for soliton generation at the edge of the visible band. Here, we show that the optical soliton formed in this way is analogous to optical Bragg solitons and, more generally, to the Dirac soliton in quantum field theory. This optical Dirac soliton is studied theoretically, and a closed-form solution is derived in the corresponding conservative system. Both analytical and numerical solutions show unusual properties, such as polarization twisting and asymmetrical optical spectra. The closed-form solution is also used to study the repetition rate shift in the soliton. An observation of the asymmetrical spectrum is analysed using theory. The properties of Dirac optical solitons in microresonators are important at a fundamental level and provide a road map for soliton microcomb generation in the visible band

Development of a standardized in-hospital cardiopulmonary resuscitation set-up

Objective. This study evaluated whether chest compression in a standardized inhospital cardiopulmonary resuscitation (CPR) set-up can be performed as effectively as when the rescuer is kneeling beside the patient lying on the floor. Specifically, the in-hospital test was standardized according to the rescuers’ average knee height. Methods. Experimental intervention (test 1) was a standardized, in-hospital CPR set-up: first, the bed height was fixed at 70 cm. Second, the height difference between the bed and a step stool was set to the average knee height of the CPR team members (45 cm). Control intervention (test 2) was kneeling on floor. Thirty-eight medical doctors on the CPR team each performed 2 minutes of chest compressions in test 1 and 2 in random order (cross-over trial). A Little Anne was used as a simulated patient who had experienced cardiac arrest. Chest compression parameters, such as average depth and rate, were measured using an accelerometer device. Results. In all tests, the average depths were those recommended in the most recent CPR guidelines (50–60 mm); there were no significant differences between Tests 1 and 2 (53.1 ± 4.3 mm vs. 52.6 ± 4.8 mm, respectively; p = 0.398). The average rate in Test 2 (119.1 ± 12.4 numbers/min) was slightly faster than that in Test 1 (116.4 ± 10.2 numbers/ min; p = 0.028). No differences were observed in any other parameters. Conclusions. Chest compression quality in our standardized in-hospital CPR set-up was similar with that performed in a kneeling position on the floor. Trial Registration: Clinical Research Information Service: KCT000159