차체 구조용 알루미늄 합금의 이종 통전고상 점접합 연구

최현석,차승비,김진철,홍성태,이창주,남기석 한국정밀공학회 2024 한국정밀공학회지 Vol.41 No.4

A feasibility study of electrically assisted solid-state spot joining (EASSJ) of dissimilar aluminum alloys for automobile structures was conducted. EASSJ of dissimilar automotive aluminum alloys (AA6451 and AA6014) was conducted by simultaneously applying step-by-step current and compressive load to the faying interface (lap spot joining), while the temperature was controlled to be lower than melting points of joining alloys. To evaluate the soundness of the joint, a nugget pull-out fracture mode under shear tensile test was set as a criterion. Microstructure analysis was also conducted to evaluate characteristics of the joint. Experimental results suggest that the EASSJ is clearly feasible in joining dissimilar aluminum alloys for automobile structures.

유기자재와 강수량이 수수${\times}$수단그라스 교잡종의 질소이용효율에 미치는 영향

최현석,이연,정정아,지형진,이상민,국용인,정석규,Choi, Hyun-Sug,Lee, Youn,Jung, Jung-Ah,Jee, Hyeong-Jin,Lee, Sang-Min,Kuk, Yong-In,Jung, Seok-Kyu 한국유기농업학회 2012 韓國有機農業學會誌 Vol.20 No.3

탄질비가 다른 유기자재 시용이 토양중 무기태질소의 시기별 변화와 수수${\times}$수단그라스 교잡종의 질소이용률에 미치는 영향을 조사하기 위해서 2009년부터 2011년까지 수행되었다. 처리구는 질소함량 210kg/ha 수준으로 축분퇴비, 알팔파, 유박, 포함하였다. 유박은 가장 낮은 탄질비를 나타내었고, 축분퇴비는 3년 동안 가장 낮은 질소의 무기화가 관찰되었다. 토양 무기성분과 수수${\times}$수단그라스 교잡종의 건물중은 처리에 따라 일관성 있게 영향을 받지 않았고, 건물중은 재배기간인 5월부터 9월까지의 강수량과 부의 상관관계를 나타내었다. 화학비료는 2009년과 2010년에 질소이용률을 크게 증가시켰고, 축분퇴비는 3년간 가장 낮은 질소이용률을 보였다. 6월부터 8월까지의 강수량 증가는 퇴비로 처리된 수수${\times}$수단그라스 교잡종의 질소이용률을 다소 증가시켰으나 양분의 무기화가 빠른 화학비료는 반대의 양상이 관찰되었다. 본 시험에서는 유기자재의 탄질비 보다는 강수량의 변동이 클 때 작물의 건물중과 질소이용률에 영향을 끼치므로 이를 고려하여 밭토양에 시비를 해야 할 것으로 판단되었다. This study was conducted to evaluate soil inorganic N concentrations and N uptake efficiency of sorghum ${\times}$ sudangrass hybrid (Sorghum bicolor (L.) Moench) as affected by organic nutrient sources from 2009 to 2011. The treatments included chemical fertilizer, compost, oilcake, alfalfa hay mulch, and control. Nutrient applications were made at rates equivalent to approximately 210 kg of actual N per hectare. The precipitation during the growth period from May to September was higher in 2011, followed by 2009, and 2010. Oilcake had the lowest C:N ratio in the raw materials. Compost treatment slowed N-mineralization rate in soil during the measured years. Soil mineral nutrition and dry matter production were not consistently affected by treatments, but the dry matter production was negatively correlated with the amount of precipitation from May to September for three years. Chemical fertilizer treatment increased N efficiency in plants in the first two years, observing with lower N efficiency in plants treated with compost for 3 years. Increased precipitation from June to August improved N efficiency in sudangrass plants treated with compost but reduced the efficiency with the chemical fertilizer. Total dry matter production and N efficiency in plants were not affected by the C:N ratio of the raw materials rather than weather condition.

횡격막에 적용된 테이핑 처치가 30초간의 무산소 운동수행력에 미치는 영향: pilot study

최현석,조일영,Choi, Hyun-Seok,Cho, Il-Young 한국디지털정책학회 2022 디지털정책학회지 Vol.1 No.1

The purpose of this study was to investigated the effect of taping intervention applied to the diaphragm on the anaerobic performance in 30 seconds. 18 healthy college students were randomly divided into experimental group(KT=9) and control group(Sham=9). In both groups, pre and post measurement was performed by wingate test, and post measurement was performed with taping application after a week rest. The statistics between two groups on the rate of change pre and post were analyzed through Mann-Whitney U test. Statistically, it showed that only the average power(AP) of control group was significantly different. This means that diaphragmatic taping did not affect the performance of anaerobic exercise for 30 seconds. However, considering the increase in aerobic metabolism during long-term anaerobic exercise longer than 30 seconds, further studies on anaerobic exercise performance within various time ranges are needed.

수용성 칼슘 및 IBA 처리가 '부유' 단감의 엽과 토양 내 칼슘함량에 미치는 영향

최현석,김영,김월수,이연,최경주,정석규,Choi, Hyun-Sug,Kim, Young,Kim, Wol-Soo,Lee, Youn,Choi, Kyeong-Ju,Jung, Seok-Kyu 한국유기농업학회 2010 韓國有機農業學會誌 Vol.18 No.3

`부유' 단감은 주로 MA를 통해서 저장되지만, 저장기간 동안 과육의 과정부 갈변과 과피 흡변을 가져와서 과실의 품질을 저하시킨다. 칼슘은 세포막에 중요한 역할을 하며 칼슘과 관련된 과실 생리장해를 경감시킨다. 본 연구는 수용성 칼슘 관주와 엽면살포가 토양의 화학성, 근활력 그리고 엽 내 무기성분에 어떠한 영향을 미치는지에 에 대해서 조사하였다. 칼슘 관주(Ca-FG)와 칼슘과 IBA를 혼용한 관주(Ca+IBA)처리는 대조구(Cont), 칼슘 엽면살포(Ca-FA), 그리고 IBA관주처리 (IBA)보다 높은 토양 칼슘함량을 보였으며, 토양 내 칼슐함량의 증가는 pH를 상승시키는 경향을 보였다. Ca+IBA처리는 근활력을 증가시켰다. 엽내 칼슘은 CA-FA에 증가되었고, Ca+IBA와 Ca-FG에 의해서도 증가하는 경향이 나타났다. Sweet persimmon, 'Fuyu', is the major cultivar for MA storage, but browning of blossom end part and fruit surface darkening occur during storage and decrease fruit qualities in fresh fruit market. Calcium (Ca) has a very important role in cell membrane and reduces Ca-related fruit disorder. Therefore, this study was conducted to investigate the effect of soluble Ca fertigation and foliar applications on soil chemical properties, root activity, and leaf nutrient status. Ca concentration in the soil was higher in both Ca fertigation (Ca-FG) and Ca+IBA fertigation (Ca+IBA) treatments than the other treatments, such as control (Cont), Ca foliar application (Ca-FA), and IBA fertigation (IBA). The increase in soil Ca improved soil pH. The Ca+IBA treatment increased root activity. Leaf Ca concentration was significantly increased by the CA-F A application, followed by Ca+IBA, and Ca-FG treatments.

Decreased Expression of Sphingosine-1-Phosphate Receptor 1 in the Blood Leukocyte of Rheumatoid Arthritis Patients

최현석,김경훈,진서훈,김진현,유인설,백승필,하운환,박태원,최수안,육순홍,강성욱,정용우 대한면역학회 2018 Immune Network Vol.18 No.5

Sphingosine-1-phosphate (S1P) plays an important role in trafficking leukocytes and developing immune disorders including autoimmunity. In the synovium of rheumatoid arthritis (RA) patients, increased expression of S1P was reported, and the interaction between S1P and S1P receptor 1 (S1P1) has been suggested to regulate the expression of inflammatory genes and the proliferation of synovial cells. In this study, we investigated the level of S1P1 mRNA expression in the blood leukocytes of RA patients. In contrast to the previous reports, the expression level of this gene was not correlated to their clinical scores, disease durations and ages. However, S1P1 was transcribed at a significantly lower level in the circulating leukocytes of RA patients when compared to age-, and sex-matched healthy controls. Since these data may suggest the participation of S1P1, further studies are needed to determine the role of this receptor in the pathogenesis of RA.

하악 Milled Bar 임플란트 피개의치에서 12년 간의 임플란트 주변 치주조직 및 의치의 변화

최현석,조진현 대한치과보철학회 2021 대한치과보철학회지 Vol.59 No.1

하악은 상악보다 지지 면적이 적고, 특히 전반적인 치조골 흡수가 진행된 환자에서는 혀와 하악골의 움직임으로 인해 통상적인 총의치의 경우 의치의 안정성과 저작 효율이 현저히 낮다. 이러한 환자에 있어 소수의 임플란트를 이용한 임플란트 피개의치는 유지력과 안정성이 높고 발음이나 저작력 면에서도 우수한 예지성 있는 치료방법으로 평가되고 있다. 본 증례에서는 상악의 무치악, 하악의 전반적인 치조골 흡수를 보이는 환자에 있어 상악에는 총의치, 하악에는 4개의 임플란트를 식립하여 milled bar를 이용한 임플란트 피개의치를 제작하였다. 이후 12년 동안 임플란트 주변의 치주조직의 변화를 지속적으로 관리 및 관찰하였고, 변화 사항 및 보철물의 정기적인 관리에 대해서 보고하고자 한다.

사과 유기재배 시 무기성분 함량과 수체생장과 피해에 미치는 영향

최현석,정석규 한국유기농업학회 2017 韓國有機農業學會誌 Vol.25 No.3

Correlations of soil and leaf nutrients and growth of young ‘Enterprise’ apple (Malus × domestica Borkh.) trees were analyzed with tree damage, such as Japanese beetle (JB; Popillia japonica Newman)-damaged leaves, vole damage to trunk, tree mortality, and weed density in a certified organic orchard in warm and humid environment of Southern USA. Interaction treatments of four mulch and three fertilizers were applied around trees as follows: mow-and-blow (MB), shredded paper (SP), wood chips (WC), and green compost (GC) as a mulch, with no fertilizer (NF), poultry litter (PL), and commercial organic fertilizer (CF) as a fertilizer applied in April. Vole damage to trunk and weed density were little correlated with mineral nutrients and tree growth. JB-damaged leaves were highly stimulated to 26.5% in GC-treated plots while tree mortality were increased by MB treatments. Biomass production per tree was approximately 3,700 g on the WC- and GC-treated plots, which was two times higher than those values observed on the other two mulch plots. JB-damaged leaves tended to get worse when nutrients in soil and leaf increased through the correlation analysis, with a strong positive relationship (r2 = 0.585) observed between JB-damaged leaves and trunk cross sectional area, a vegetative indicator. Tree mortality was more negatively associated with nutrient contents and growth of trees than those of soil nutrients. Wood chips was considered for a local organic mulch materials to increase organic matter contents and to produce healthy young trees in Southern USA, with control insect, such as beetle, and vole density in an orchard habitat.

[Global] 시진핑 자유무역 주창은 헛구호··· `어떻게`가 없다

최현석 연합뉴스 동북아센터 2017 마이더스 Vol.2017 No.6

류마티스 관절염 치료에 대한 고찰

최현석,Choi, Hyun-Suk 대한물리치료과학회 1997 대한물리치료과학회지 Vol.4 No.4

For the perfect cure of rheumatoid arthritis, the ultimate hope of patients and therapist, it is necessary to find a patient early and treat him properly and to teach him what rheumatoid arthritis is. 1. Although rheumatoid arthritis is a chronic disease and its cause is uncertain matke the patient understand that there are many ways to reduce symptoms and to prevent deformation. 2. Explain the peculiarity and the procedure of rheumatoid arthritis to the patient and encourage him. 3. Teach the patient how to protect his arthrosises by showing him concrete movement. 4. Teach the patient or his family the ways to relieve rheumatoid arthritis easily in his house for continuous remedy. In order to make that remedy most effective for the patient, a complex and balanced treatment, considering medication, surgical teatment and rehabilitative treatment, has to be applied, which needs team work. Team work occurs when doctors, physiotherapists, nurses, nutritionists, clinical psychologists, prosthesis manufacturers, social workers, employment agents and the family of the patient work together. The members of the tern have to onderstand the procedure of the treatment of rheumatoid arthritis and apply proper remedies according to the condition of the patient.

후방보행 훈련이 뇌졸중 환자의 균형능력 및 보행에 미치는 영향

최현석,전선복 한국디지털정책학회 2015 디지털융복합연구 Vol.13 No.1