• Journal of the Microelectronics and Packaging Society
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• v.28 no.4
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• pp.85-89
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• 2021

AlGaN-based UV-C light-emitting diodes (LEDs) were applied for p-type activation by electrochemical potentiostatic activation (EPA). The p-type activation efficiency was increased by removing hydrogen atoms through EPA treatment using a neutral Mg-H complex that causes high resistance and low conductivity. A neutral Mg-H complex is decomposed into Mg^- and H⁺ depending on the key parameters of solution, voltage, and time. The improved hole carrier concentration was confirmed by secondary ion mass spectroscopy (SIMS) analysis. This mechanism eventually improved the internal quantum efficiency (IQE), the light extraction efficiency, the leakage current value in the reverse current region, and junction temperature, resulting in better UV-C LED lifetime. For systematic analysis, SIMS, Etamax IQE system, integrating sphere, and current-voltage measurement system were used, and the results were compared with the existing N₂-annealing method.

• 한국노년학
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• v.40 no.3
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• pp.429-442
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• 2020

The purpose of this research was to examine changes in the physical fitness, activities of daily living performance, and cognitive status of the frail elderly by combined exercise programs. The combined exercise program consisted of an aerobic exercise for the elderly and a four-color ladder exercise for improving of cognitive ability and physical fitness. Twenty-one frail elderly participated in this study, they were divided into 12 exercise groups and nine control groups. The exercise group conducted the combined exercise program of 60 minutes, twice a week, for10 weeks, while the control group maintained their normal lives. Strength, flexibility, agility, coordination, ADL and MMSE-K were measured. Exercise group showed significant improvement in grip strength compared to control group. In addition, ADL showed significant improvement only in the exercise group. The results of this study showed that participation in the combined exercise program of the el derl y was effective in improving the grip strength, and in preventing various physical functions and cognitive conditions decline.

• Therapeutic Science for Rehabilitation
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• v.11 no.3
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• pp.81-92
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• 2022

Objectives : This study aimed to investigate the effect of beat-keeping games in smartphone applications on improving executive functions in children with developmental delays. Methods : Three children diagnosed with developmental delay were included in this study. The ABA design used a single-subject experimental research design. The independent variable was the beat-keeping game. The game was held three times a week for a total of seven times for 20 minutes, including breaks. The dependent variable, "Visual-motor speed," was measured every session to assess if the beat-keeping game was effective in improving the participant's executive function. Further, before and after the intervention, "Children's Color Trails Test (CCTT)", "Block design," and "Finding hidden picture" were measured. Results : All three participants showed improvement in the performance of the beat-keeping game and the executive functions of "Visual-motor speed" and visual attention. Conclusions : Based on the results of this study, various effective applications for learning and intervention can be developed and applied to children with developmental delays who have difficulty in motivating themselves and lack attention.

• The Journal of Korean Academy of Sensory Integration
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• v.20 no.3
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• pp.60-71
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• 2022

Objective : This study aimed to summarize and present the effects of group sensory integration treatment applied to children with and without disabilities in Korea. Methods : The search period was from January 2010 to December 2021, and databases of 'The Journal of Korean Academy of Sensory Integration', 'The Korean Journal of Occupational Therapy', 'Koreanstudies Information Service System', 'Research Information Sharing Service', 'DBpia' were used for data search. A total of 11 studies were selected, and the Patient, Intervention, Comparison, Outcome method was applied to organize them systematically. Results : As a result of the study, single-group non-randomized studies were the most common with 8 out of 11 studies (72.73%). There were 99 subjects, ranging in age from 3 to 11, and an average of 7.39. Among them, there were more children with disabilities, and 40 out of 99 (40.41%) were diagnosed with developmental disabilities the most. A total of 5 to 45 treatment intervention sessions were provided, and 60 minutes were the most frequently provided once or twice a week. The Canadian Occupational Performance Measure and The Penn Interactive Peer Play Scale were the most commonly used evaluation tools in 4 times each (12.90%). As the treatment intervention goal, social interaction skills was the most common with 8 studies (36.36%). As a result of treatment intervention, 8 studies showed significant results. Conclusion : Based on this study, it is expected that in the future, various methods of intervention of sensory integration therapy based on high quality levels can be systematically presented and used as useful information in clinical practice.

• The Korean Journal of Nuclear Medicine Technology
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• v.26 no.2
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• pp.32-36
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• 2022

Purpose There are reports that the COVID-19 vaccine causes false positive uptake of axillary lymph nodes. Therefore, this paper intends to evaluate the change in SUVmax of axillary lymph nodes with the period after the COVID-19 vaccination. Materials and Methods In 134 breast cancer patients who were tested for ¹⁸F-FDG PET/CT at Severance hospital, 3.7 MBq/kg of ¹⁸F-FDG was intravenously injected and scanned for 2 minutes per bed after 60 minutes. The equipment was Discovery 600 (GE Healthcare, MI, USA). The period was divided into four groups, 0 to 2 weeks, 3 to 6 weeks, 7 to 10 weeks, and 11 weeks or more. SUVmax was measured after checking the uptake of axillary lymph nodes on the ipsilateral side of vaccination and the Kruskal-Wallis test was performed using SPSS Statistics 28 (IBM Corp., Armonk, NY, USA). Results From 0 to 2 weeks groups to 11 weeks or more group, the average of SUVmax was measured in the order of 5.52, 2.85, 1.82, and 1.7. As a result of the Kruskal-Wallis test, there was a significant difference between 0 to 2 weeks group from all other groups (P < 0.05), and there was no significant difference between the remaining three groups. Conclusion The SUVmax of axillary lymph nodes decreased over the period after the COVID-19 vaccination and no significant difference was found after 3 weeks of vaccination. Therefore, it is recommended to record COVID-19 vaccination information before examination.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.35.5-36
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• 2021

'역상고성'은 '신법산서'에 수록되어 있는 티코브라헤의 역법체계와 그 밖의 천문 내용들을 중국인 천문학자들에 의하여 확실하게 정리를 하였지만 '역상고성'에 따른 추보는 천상과 불일치를 보게 되었다. 藪內淸(야부우치 키요시) 저(1969), 유경로 역(1985)에 의하면 이러한 불일치는 옹정 8년 6월 초 1일의 일식이었는데 예보의 오류를 정정한다는 것을 중국 천문학자들이 감당하기 어려웠다. 퀘글러(Ignatius Kögler, 戴進賢, 1680~1746)와 페레이라(Andreas Pereira, 서무덕(徐懋德), 1690-1743) 등의 선교사 천문학자들이 칙명을 받아 종사하게 되고, 이들이 중심이 되어 '역상고성'보다 더 진보된 서양천문 역법에 기초를 둔 역서가 편찬되게 되었다. '신법산서'와 '역상고성'은 모델에서는 평원(平圓)을 사용하지만 '역상고성후편'에서는 타원(楕圓) 모델을 사용하게 된다. 건륭 7년(1742년)에 10권이 완성되어 '역상고성후편'이라 명하였다. 타원모델을 채택하였지만 지동설에 대한 내용은 전혀 기술되어 있지 않다. 아마도 태양이나 달의 운동을 추보하는데 지구를 중심으로 해야 하기에 이에 대한 언급을 필요치 않았을 수도 있다. '역상고성후편' 은 태양과 달의 운행, 일식과 월식에 대해서만 다루고 있다.그러나 '역상고성'에서는 청몽기차나 지반경차를 티코브라헤의 표 값을 그대로 사용하였고, 이 값들이 관측과 관련이 되어 있음을 설명하려는 무리를 두고 있다. 너무 정확하게 값들이 관측 값들로부터 유도되어 의심이 갈 정도이다. 카시니(Giovanni Domenico Cassini, 喝西尼, 1625~1712)는 자신의 동료 리셰와 함께 파리와 프랑스령 기아나 카이엔에서 충의 위치에 있는 화성과 부근 별의 고도를 관측하여 충의 위치에 있는 화성의 시차를 측정하여 최초로 태양과 지구 사이의 거리를 어림하고, 태양의 지반 경차를 현재와 값과 거의 비슷하게 얻었다. '역상고성후편'에서는 이 내용을 상세하게 다루고 있다. 또한 대기에서 입사각과 굴절각 사이에 Snell의 법칙이 성립하는데 이를 이용하여 모호하게 알았던 청몽기차를 대기의 굴절을 이용하여 현재의 값과 비슷한 값을 얻어 사용할 수 있게 되었다. 이는 모든 천체의 위치를 관측하는데 있어서 매우 정확한 값들을 얻을 수 있게 되고 이에 따라 황도-적도 경사각도 정확하게 얻어진다. '역상고성후편'은 옹정원년을 역원으로 하고 있다. 태양의 운행에 있어서 케플러의 타원 궤도를 이용하게 된다. '신법산서'와 '역상고성'에서는 평균근점이각 M을 모델에서 보여 줄 수 있지만 타원 궤도에서는 이 각이 면적각으로 주어지고, 원 대신 타원을 다루기에 쉽지 않다. 현재는 케플러 방정식을 풀어 가감차를 구하게 되는데 이를 기하학적으로 풀이하는 차적구적법을 소개하고 있다. 이와 함께 면적을 이용하여 타원계각과 타원차각을 구하는 차각구각법도 소개한다. 타원계각과 타원차각을 모두 고려하였기에 현재의 태양의 운동을 기술하는 타원모델과 완벽하게 같다. 다만 사용하는 상수가 아주 조금 다를 분이다. 태양의 경도를 추보하는 방법도 동지점을 기준으로 하고 현재의 방법과 동일하다. 달의 운행도 타원 궤도를 사용한다. '역상고성후편'의 내용은 우리나라의 전해져서 1860년 남병길이 쓴 '시헌기요(時憲紀要)'에는 태양, 달, 일·월식, 오행성의 운동, 항성의 위치, 시간 등을 추보하는데 필요한 내용들이 매뉴얼화 되어 기록되어 있고, 1862년 남병철이 쓴 '추보속해(推步續解)'에도 같은 내용을 담고 있다.

• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.472-478
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• 2023

In this study, the acetaldehyde removal characteristics of activated carbon (AC) for air purifier filters were investigated using metal catalysts-impregnation and functional group-modification method. The AC with a high specific surface area(1700 m²/g) and micropores was prepared by KOH activation of coconut charcoal and the efficiency of catalyst and functional group immobilization was examined by varying the drying conditions within the pores after immersion. The physical properties of the prepared activated carbon were analyzed by BET, ICP, EA, and FT-IR, and the acetaldehyde adsorption performances were investigated using gas chromatography (GC) at various impregnation and modified conditions. As the concentration of impregnation solution increased, the amount of impregnated metal catalysts increased, while the specific surface area showed a decreasing trend. The adsorption tests of the metal catalyst-impregnated and functional group-modified activated carbons revealed that excellent adsorption performance in compositions MgO10@AC, CaO10@AC, EU10@AC, and H-U3N1@AC, respectively. The MgO10@AC, which showed the highest adsorption performance, had a breakthrough time of 533.8 minutes and adsorption capacity of 57.4 mg/g for acetaldehyde adsorption. It was found that the nano-sized MgO catalyst on the activated carbon improved the adsorption performance by interacting with carbonyl groups of acetaldehyde.

• 한국체육학회지인문사회과학편
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• v.55 no.3
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• pp.543-551
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• 2016

The study was aimed at investigating the relationship between biomechanical properties of cervical muscles and smartphone addiction score in fifty healthy males using smartphone more than 60 minutes each day. The usage of smartphone was evaluated by smartphone addiction survey developed from Korean International Society Agency. Biomechanical properties of three major cervical muscles; splenius capitis, sternocleidomastoid and upper trapezius, were measured by Myoton, and conducted five parameters; frequency, decrement, stiffness, creep, and relaxation time. As results, all parameters had less than 2% of coefficient of variation(CV) between measurement intervals. Also, intra-class correlation coefficient(ICC) indicated a high reliability(ICC>.9, p<.01). Moreover, the smartphone addiction score was significantly different in frequency(r=.353, p<.05) and stiffness(r=.346, p<.05) on upper trapezius; in addition, in decrement(r=-.284, p<.05) and creep(r=.288, p<.05) on sternocleidomastoid. Especially, splenius capitis was closely related with the overuse of smartphone(frequency, r=-.368, p<.01; decrement, r=-.405, p<.01; stiffness, r=-.424, p<.01). In conclusion, this study implied that the overuse of smartphone is significantly related with the damage of cervical muscles, cervical pain, and headache; furthermore, Myoton can be used as an effective device to assess mechanical properties of cervical muscles.

• Analytical Science and Technology
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• v.19 no.5
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• pp.441-448
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• 2006

11-nor-9-carboxy-${\Delta}^9$-tetrahydrocannabinol (THCCOOH) is the major metabolite of tetrahydrocannabinol (THC) which is the primary psychoactive component of marijuana. It is also the target analyte for the discrimination marijuana use. A method using solid-phase extraction (SPE) and gas chromatography/mass spectrometry (GC/MS) was developed for the determination of THCCOOH in human urine. Urine samples (3 mL) were extracted by SPE column with a cation exchange cartridge after basic hydrolysis. The eluents were then evaporated, derivatized, and injected into the GC/MS. The limits of detection (LOD) and quantitation (LOQ) were 0.4 and 1.2 ng/mL, respectively. The response was linear with a correlation coefficient of 0.999 within the concentration range of 1.2 (LLE 1.3)~50.0 ng/mL. The precision and accuracy were stable within 1.20% and the recovery was 83.6~90.7%. The recovery of SPE method was lower than that of liquid-liquid extraction (LLE), but there were no apparent differences in LOD, LOQ, precision and accuracy between the two methods. While SPE method is used as a very effective and rapid procedure for sample pretreatment, and clean extracts, LLE method was not suitable for the extraction procedure of THCCOOH in urine. The applicability of the method was proven by analyzing a urine samples from a marijuana abusers.

• Journal of Korea Entertainment Industry Association
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• v.13 no.8
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• pp.619-626
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• 2019

This study was conducted to investigate the effects of a participatory rehabilitation program on sit-rise and rise-to-walk test performances, and perception and motor skills in adults with medically vulnerable individuals and, adults with developmental disabilities in particular. Seventeen adults with developmental disabilities participated in a participatory rehabilitation program using resistance bands and exercise balls, for 60 minutes once weekly over 13 weeks. Their performances were measured before and immediately after the intervention, and 12 weeks after. The findings were as follows. In the sit-rise test, the number of times rising from sitting posture increased after the intervention versus before, but the difference was not statistically significant. In the rise-to-walk test, the performance showed statistically significant difference over time, and the post-hoc test showed a significant effect after the intervention versus before. There was no significant difference in perception and motor skills. In sum, the participatory rehabilitation program positively influenced dynamic balancing related to functional activities but had no significant effect on perception and motor skills, which is related to motor control and motor learning. It is suggested that to increase the participation in community activities, reduce fall risk, and improve dynamic balancing abilities in adults with developmental disabilities, participatory rehabilitation programs should be utilized to promote the physical wellbeing.