Quasi 3D ECE imaging system for study of MHD instabilities in KSTAR

A second electron cyclotron emission imaging (ECEI) system has been installed on the KSTAR tokamak, toroidally separated by 1/16th of the torus from the first ECEI system. For the first time, the dynamical evolutions of MHD instabilities from the plasma core to the edge have been visualized in quasi-3D for a wide range of the KSTAR operation (B0 = 1.7???3.5 T). This flexible diagnostic capability has been realized by substantial improvements in large-aperture quasi-optical microwave components including the development of broad-band polarization rotators for imaging of the fundamental ordinary ECE as well as the usual 2nd harmonic extraordinary ECE.open1

A Power-Efficient Resonant Current Mode Receiver With Wide Input Range Over Breakdown Voltages Using Automated Maximum Efficiency Control

This article proposes a series-LC resonant current mode receiver (RCM R-X) for wirelessly powered battery chargers. With a series-LC scheme, the RCM R(X )can operate at higher resonant voltages than transistor breakdown voltages, enabling robust near-field wireless power transfer. In the series-LC RCM R-X, a dual automated maximum efficiency control (AMEC) and a passive zero-current detector (ZCD) adaptively adjust operation states, ensuring nonresidual energy in the R-X LC tank at the end of the charging mode. Moreover, the passive ZCD operation algorithm increases the power delivered to the load or battery by minimizing the idle period between charging and resonant modes. The 180nm standard CMOS chip, which used only 1.8-V transistors, can operate with 6.84x higher resonant voltage up to 12.32 V than the transistor breakdown voltage, 1.8 V, while receiving an input power up to 169 mW, enabling a wide input range over variable coil distances. The proposed system achieves the measured power conversion efficiency up to 84.9% at the input power of 16.8 mW

Toroidal mode number transition of the edge localized modes in the KSTAR plasmas

Rapid transitions of the toroidal mode number (n) have been often detected during the evolution of the edge localized modes (ELMs) in the inter-ELM-crash periods of the KSTAR tokamak plasmas. The mode number transitions accompany changes of the mode frequency (f(mode)) (e.g. n changed from 8 to 5 while f(mode) changed from similar to 32 to 9 kHz). The observed transition phenomena have been diverse including small and large increase (or decrease) in the mode number and multiple transitions during a single inter-ELM-crash period. Two classes of the mode transitions were identified: non-overlapping transition and overlapping transition. The former case is characterized by the absence of coherent filamentary structure during the transition and the latter case is characterized by co-existence of two coherent filamentary structures with different mode numbers. Each transition process typically lasts a few hundreds to thousands of mu s.close0

Public Health and Informatics: Proceedings of MIE 2021

Due to the corona (COVID-19) pandemic, several countries are currently conducting non-face-to-face education. Therefore, teachers of nursing colleges have been carrying out emergency remote education. This study developed a questionnaire to understand the status of Emergency Remote Learning (ERL) in nursing education internationally, translated it into 7 languages, and distributed it to 18 countries. A total of 328 nursing educators responded, and the most often used online methods were Social networking technology such as Facebook, Google+ and Video sharing platform such as YouTube. The ERL applied to nursing education was positively evaluated as 3.59 out of 5. The results of the study show that during the two semesters nursing college professors have well adapted to this unprecedent crisis of teaching. The world after COVID-19 has become a completely different place, and nursing education should be prepared for ‘untact’ education.</p