• Journal of Electrical Engineering and Technology
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• v.1 no.3
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• pp.351-358
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• 2006

In this paper, the electrical characteristics of the contactless transformer is presented using the conventional coupled inductor theory. Compared with the conventional transformer, the contactless transformer has a large airgap, long primary wire and multi-secondary wire. As such, the contactless transformer has a large leakage inductance, small magnetizing inductance and poor coupling coefficient. Therefore, large magnetizing currents flow through the entire primary system due to small magnetizing inductance, resulting in low overall system efficiency. In high power applications, the contactless transformer is so bulky and heavy that it needs to be split by some light and small transformers. So, the contactless transformer needs several small transformer modules that are connected in series or parallel to transfer the primary power to the secondary one. This paper shows the analysis and measurement results of each contactless transformer module and comparison results between the series- and parallel-connection of the contactless transformer. The results are verified on the simulation based on the theoretical analysis and the 30kW experimental prototype.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.2
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• pp.49-59
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• 2022

The relationship between income inequality and capital account openness is empirically investigated in this study, where macroeconomic variables have opposing effects. Panel data used in the study from the KAOPEN Index and World Bank consists of 28 Asian countries and has been examined; it contains annual observations from 1970 to 2018. The data is examined using a random-effect model based on GMM estimates. Income inequality and capital account openness are positively and significantly related, according to our findings. Overall, the findings imply that increasing income gaps reduced capital investment in nations with large discrepancies. The growing economic discrepancy is being caused by the rich's increasing income share at the expense of the poor. In Asia, inward capital account openness exacerbates income inequality, while outward capital account openness exacerbates it. As a result, income inequality slows economic growth, leading to inflation, unemployment, and increased government spending in several Asian countries. Our control factors, GDP, and other secondary school enrolments, all had a statistically significant negative relationship with income inequality. Income disparity has a positive and statistically significant association with government spending, inflation, population, trade openness, and unemployment. Income disparity has a negative association with capital account openness, gross domestic product, and secondary school enrollment.

• Analytical Science and Technology
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• v.8 no.4
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• pp.583-590
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• 1995

Pitch-based mesophase carbon fibers prepared at different temperatures were heat-treated at temperatures lower than those of the preparation and the electrochemical Li doping/undoping characteristics were evaluated in relation to the data of IR, mass, etc. Presence of surface hydroxyls were confirmed by FTIR for lower temperature sample which showed poor anode characteristics. Upon oxidative heating, removal of surface hydroxyls took place, resulting in a remarkable improvement of the electrode characteristics. At the same time, surface roughening took place, which was confirmed by SEM and double layer capacity measurements. In situ mass spectra obesrved during the heat-treatments showed gas evolution of $H_2O$, CO, $CO_2$, $C_2H_4$, and/or $H_2$ depending on the conditions. These data together with those of weight loss and conductivity provided us a valuable information in regard to the evaluation of the electrochemical characteristics.

• Transactions of the Korean hydrogen and new energy society
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• v.3 no.2
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• pp.45-54
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• 1992

An applicability microencapsulation, using electroless copper plating, of hydrogen storage alloy powder as an anode material for nickel-hydrogen secondary batteries was investigated. Alloys employed were $LaNi_{4.7}Al_{0.3}$ and $MmNi_{4.5}Al_{0.5}$(Mm=mischmetal) which have an appropriate equilibrium pressure and capacity. The microencapsulation of the alloy powder was found to accelerate initial activation of electrodes and to increase capacity which is about 285mAh/g for $LaNi_{4.7}Al_{0.3}$. In addition, other charge and discharge characteristics, such as polarization and flatness of charge and discharge potential, were improved due to the role of copper layer as a microcurrent collector and an oxidation barrier of the alloy powder. $MmNi_{4.5}Al_{0.5}$ alloy showed lower capacity than $LaNi_{4.7}Al_{0.3}$ because of higher equilibrium pressure. Cyclic characteristics of both alloys were somewhat poor because of mainly shedding and partial oxidation of alloy powder during the cycling. However, it was considered that the microencapsulation method is effective to improve the performances of the hydrogen storage alloy electrodes.

• Journal of the Korean Electrochemical Society
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• v.16 no.1
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• pp.9-18
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• 2013

Components of zinc-air battery and their problems are explained. Energy density of zinc air battery is superior to other commercial ones including Li-ion batteries. Cycle life of the zinc air batteries is poor because of irreversible redox reactions on both electrodes. In order to improve the performance of the zinc air battery, catalysts, passivation, and the new structure of electrodes should be developed to optimize several reactions in an electrode. Multidisciplinary efforts, such as mechanics, corrosion science, composite materials are necessary from the beginning of the research to obtain a meaningful product.

• Advances in pediatric surgery
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• v.4 no.2
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• pp.131-136
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• 1998

Lymphangioma is a congenital malformation of the lymphatic system that expands into the surrounding tissues in a manner similar to a malignant tumor. Surgical excision has been the treatment of choice, but the results are often unsatisfactory due to incomplete resection, fluid collection and recurrences. Intralesional injection of OK-432(lyophilized incubation mixture of Group A Streptococcus pyogenes of human origin) was employed in treating 24 patients with lymphangiomas between 1992 and 1997. The method was used in 21 patients as a primary therapy, and in 3 patients for unresectable or recurrent cases as a secondary treatment. The results were excellent in 8 patients (33.3%), good in 7 patients (21.8 %) and poor in 7 patients (21.8 %). The side effects were fever under $39^{\circ}C$ and local inflammation. However these symptoms subsided in a few days without serious sequelae. These results suggest that intralesional injection of OK-432 is safe and effective treatment for primary lymphangioma as well as a secondary therapy for unresectable or recurrent cases.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.294-294
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• 2007

Spinel cathode material $LiMn_2O_4$ is currently studied as a promising cathode material for lithium ion secondary batteries for future applications because of it is low cost, easy to be prepared and capable to be operated in high voltage range. However as a cathode material, $LiMn_2O_4$ performs a poor capacity retention which leads to short cycle life. In this study, stoichiometric $LiMn_2O_4$ was synthesized with granulation method with ion substitution to stabilize its structure and niobium doping to improve its conductivity. These well-mixed powders were calcined at $850^{\circ}C$ for 6 hours and its properties were investigated. Correlations of dopant and electrochemical properties were examined as well.

• The Journal of Korean Society for School & Community Health Education
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• v.1 no.1
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• pp.119-130
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• 2000

The purpose of this study was to serve as a basis for more effective sex education, by examining the influence of obscene media on elementary school student's sex consciousness. For attaining the purpose, the research questions were posed as follows: 1) What's general characteristics of elementary school students? 2) How much are elementary school students exposed to obscene media? 3) Is their sex consciousness different according to the degree of being exposed to obscene media and the appearance of secondary sex characteristic? The subject of study were the 400 male and female students who were in the sixth grade at elementary school in the city of Paju. The questionnaire survey was conducted to find out their general characteristics, sex consciousness and degree of being exposed to obscene media. The conclusions were as follows; 1) Basic Information 94% of the students investigated were living with their parents. The greatest number of their parents were in their fourties. Concerning the religion of their families, 47.5% belonged to Christianity or Catholicism. 47.3% got in touch with obscene media, which indicated that the harmful influence of that media was great. Their basic knowledge of pregnancy was very poor, as 27.2% weren't sure whether being pregnant could be caused only by shaking hands, hugging or kissing. 34.7% considered it a natural behavior to contact the other sex. Regarding their practice of sexual behavior, they'd have an experience of hugging or kissing. 2) Group Comparison The female students underwent the appearance of secondary sex characteristic faster than the male students. As a result of examining if their degree of being exposed to obscene media was affected by the presence or absence of secondary sex characteristic, no statistically significant difference existed in all the groups: the entire group, male student group and female student group. There appeared, however, statistically significant differences between male and female students, as the number of male student who hadn't yet been exposed to obscene media was less than that of female student who hadn't. And the number of male student who had been much exposed to obscene media was more than that of female student who had. 3) Sex Knowledge, Sex Attitude and Sex Practice The extent of making contact with obscene media didn't make statistically significant difference to the sex knowledge of all the groups. But more extent of getting in touch with obscene media led to more sex attitude and sex practice in the entire group. However, as a result of analyzing these things by the presence or absence of secondary sex characteristic, it's found in general that the group that had secondary sex characteristic possessed statistically better sex knowledge than the other group that hadn't. For the male students, there appeared little disparities in three subareas of sex knowledge, sex attitude and sex practice. For the female students, however, the group that had secondary sex characteristic owned better sex knowledge than the other group that hadn't, and the former group looked upon sex attitude as more natural.

• Physical Therapy Rehabilitation Science
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• v.11 no.3
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• pp.311-320
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• 2022

Objective: To investigate the reliability and validity of static balance measurements using an acceleration sensor and a gyroscope sensor in smart phone inertial sensors. Design: Equivalent control group pretest-posttest. Methods: Subjects were forty five healthy adults aged twenty to fifty-years-old who had no disease that could affect the experiment. After pre-test, all participants wore a waist band with smart phone, and conducted six static balance measurements on the force plate twice for 35 seconds each. To investigate the test-retest reliability of both smart phone inertial sensors, we compared the intra-correlation coefficient (ICC 3, 1) between primary and secondary measurements with the calculated root mean scale-total data. To determine the validity of the two sensors, it was measured simultaneously with force plate, and the comparision was done by Pearson's correlation. Results: The test-retest reliability showed excellent correlation for acceleration sensor, and it also showed excellent to good correlation for gyroscope sensor(p<0.05). The concurrent validity of smartphone inertial sensors showed a mostly poor to fair correlation for tandem-stance and one-leg-stance (p<0.05) and unacceptable correlation for the other postures (p>0.05). The gyroscope sensor showed a fair correlation for most of the RMS-Total data, and the other data also showed poor to fair correlation (p<0.05). Conclusions: The result indicates that both acceleration sensor and gyroscope sensor has good reliability, and that compared to force plate, acceleration sensor has unacceptable or poor correlation, and gyroscope sensor has mostly fair correlation.

• Journal of Korean Neurosurgical Society
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• v.41 no.4
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• pp.241-245
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• 2007

Objective : So called "minimally invasive procedures" have evolved from chemonucleolysis, automated percutaneous discectomy, arthroscopic microdiscectomy that are mainly working within the confines of intradiscal space to transforaminal endoscopic technique to remove herniated epidural disc materials directly. The purpose of this study is to assess the result of endoscopic spinal surgery and favorable indication in the thoracolumbar spine. Methods : The records of 71 patients, 73 endoscopic procedures, were retrospectively analysed. Yeung Endoscopic Spine Surgery system with 7 mm working sleeve and $25^{\circ}$ viewing angle was used. The mean follow up period was 6 months [range, 3-9]. Results : Operated levels were from T12-L1 disc down to L5-L6 of S1 disc. Of 71 cases, 2 patients underwent transforaminal endoscopic surgery twice due to recurrence after initial operation. MacNab's criteria was used to assess the outcome. Favorable outcome, excellent of good, was seen in 78% [57 procedures] of the patients. Among 11 fair outcomes, only 1 procedure was followed by secondary open procedure, laminectomy with discectomy. Two of 5 poor outcomes were operated again by same procedure which resulted in fair outcomes. One patient with aggravated cauda equina syndrome remained poor and a lumbar fusion procedure was performed in other patient with poor outcome. There were 2 postoperative discitis that were treated with conservative care in one and anterior lumbar interbody fusion in the other. Conclusion : Evolving technology of mechanical, visual instrument enables minimal invasive procedure possible and effective. The transforaminal endoscopic spinal surgery can reach as high as T12-L1 disc level. The rate of favorable outcome is mid-range among reported endoscopic lumbar surgery series. Authors believe that the outcome will be better as cases accumulate and will be able to reach the fate of standard open microsurgery.