Effects of cold water immersion and protein intake combined recovery after eccentric exercise on exercise performance in elite soccer players

김형원,주창화 한국운동재활학회 2023 JER Vol.19 No.2

The purpose of this study is to analyze the effects of the combined recovery method of cold water immersion (CWI) and protein supplement intake after eccentric exercise that causes muscle fatigue in elite soccer players. Eleven semiprofessional soccer players participated in this study. Participants were divided into CWI group, combined protein and CWI group (PCWI), and passive resting group (CON). The participants completed the eccentric exercise for one hour and performed one of three recovery methods. The muscle strength of the quadriceps and hamstring muscles significantly decreased at 48-hr postexercise compared to before exercise in all recovery groups (P< 0.05), with no significantly different between the recovery groups. The time required to sprint 40 m was significantly longer in all groups at 24 hr and 48 hr after exercise than before exercise (P< 0.05). The vertical jump height was significantly decreased at 48 hr after exercise compared to before exercise in the CON and CWI groups (P< 0.05). The muscle soreness values were higher at 6 hr, 24 hr, and 48 hr after exercise than before exercise in all groups (P< 0.001). The perceived recovery quality was reduced after exercise in the PCWI (P< 0.01) and CON groups (P< 0.001) compared to before exercise; it was unchanged in the CWI group. The recovery quality decreased at 6 hr, 24 hr, and 48 hr after exercise in all recovery groups (P< 0.01). In conclusion, the combined recovery method was less effective than CWI alone for the recovery of exercise performance.

세 어머니께 허락받은 결혼

김형원 샘터사 2017 월간 샘터 Vol.572 No.-

다품종 분해라인균형 문제에 관한 발견적 기법

김형원,이광복,이동호 한국SCM학회 2008 한국SCM학회지 Vol.8 No.2

We consider a mixed-model line balancing problem for disassembly systems where used or end-of-life products are separated into parts and subassemblies for further processing. The problem, called the mixed-model disassembly line balancing problem, is to assign individual tasks for mixed models to workstations while satisfying precedence relations among tasks. The objective is to minimize the number of workstations for a given cycle time. An integer programming model is presented to describe the problem. Since the problem considered in this paper is NP-hard, we suggest heuristic algorithms in which disassembly tasks are ordered using a certain priority rule, and then they are assigned to workstations according to this order while considering the given cycle time and precedence relations. Computational experiments were done on a number of test problems up to 500 tasks, and the results are reported.

수지 노화와 잔류응력 변화가 Avimid? K3B/IM7 복합재 적층에 미치는 영향

김형원 한국군사과학기술학회 2005 한국군사과학기술학회지 Vol.8 No.3

In this paper, the effects of matrix hygrothermal aging and residual stress changes on Avimid?? K3B/IM7 laminates in 80℃ water were studied. The factors causing the 80℃ water to degradation of the laminates could be the degradation of the matrix toughness, the change in residual stresses. After 500 hours fully saturated aging of the neat resin, the weight gain was 1.55% increase with the diffusion coefficient 7×10-6m2/sand the fracture toughness was decreased about 41%. After 100 hours fully saturated aging of the [+45/0/-45/90]s K3B/IM7 laminates in 80℃ water, the weight gain was 0.41% increase with the diffusion coefficient 1×10-6m/s2 and the loss of the microcracking fracture toughness was 43.8% of the original toughness. To see whether the residual stress influenced the fracture toughtnes, two ply [90°/0°] laminates were put in 80℃ water from 2 hours to 8 hours. The changes in residual stress in 8 hours are less than 3MPa. Because the 3MPa change is not sufficient to degrade the laminates, the main factor to degrade the microcracking fracture toughness was the of the matrix fracture toughness.

Patterns and Biologic Features of p53 Mutation Types in Korean Breast Cancer Patients

김형원,정준,이학민,황승현,안성귀,이경아 한국유방암학회 2014 Journal of breast cancer Vol.17 No.1

Purpose: The p53 gene is one of the most frequently mutatedgenes in breast cancer. We investigated the patterns and biologicfeatures of p53 gene mutation and evaluated their clinical significancein Korean breast cancer patients. Methods: Patients whounderwent p53 gene sequencing were included. Mutational analysisof exon 5 to exon 9 of the p53 gene was carried out usingpolymerase chain reaction-denaturing high performance liquidchromatography and direct sequencing. Results: A total of 497patients were eligible for the present study and p53 gene mutationswere detected in 71 cases (14.3%). Mutation of p53 wassignificantly associated with histologic grading (p<0.001), estrogenreceptor and progesterone receptor status (p<0.001), HER2status (p<0.001), Ki-67 (p=0.028), and tumor size (p=0.004). The most frequent location of p53 mutations was exon 7 andmissense mutation was the most common type of mutation. Compared with patients without mutation, there was a statisticallysignificant difference in relapse-free survival of patients withp53 gene mutation and missense mutation (p=0.020, p=0.006,respectively). Only p53 missense mutation was an independentprognostic factor for relapse-free survival in multivariate analysis,with an adjusted hazard ratio of 2.29 (95% confidence interval,1.08–4.89, p=0.031). Conclusion: Mutation of the p53 gene wasassociated with more aggressive clinicopathologic characteristicsand p53 missense mutation was an independent negativeprognostic factor in Korean breast cancer patients.

태양광을 이용한 CO₂ 전환 및 자원화 기술

김형원,Kim, Hyeong-Won 한국플랜트학회 2019 플랜트 저널 Vol.15 No.2

고등학교 사회 수학 융합 프로그램이 수학 교과 태도에 미치는 효과성 분석

김형원,고호경 한국학교수학회 2017 韓國學校數學會論文集 Vol.20 No.3

본 연구는 고등학교 학생의 수학에 대한 가치 인식 및 흥미를 증진시키는 방안을 모색하 는데 일환을 두고 수행되었다. 이와 같은 교육적 목적을 달성하기 위해서는 단편적 교과 지 식의 학습 보다는 융합적인 접근을 통해 학생들이 자신의 지식을 적용할 기회가 제공되어야 한다는 주장에 따라 사회와 수학을 융합한 프로그램을 개발하고 그 적용 효과를 파악하고자 하였다. 효과성 검증을 위한 데이터 수집은 일반계 고등학교 학생들을 대상으로 사회 수학 프로그램 적용에 따른 사전 사후 설문을 통해서 이루어졌다. 사회 수학 프로그램은 실생활에 서 나타나는 사회적 현상을 수학적 관점에서 문제를 해결하고자 하는 시도로서, 적용 결과 학생들은 수학 학습 및 사회 학습에 대한 태도, 수학 학습 및 사회 학습 가치 인식에 효과적인 것을 확인할 수 있었다. The study in this paper considers how high school students’ attitudes toward and interest in mathematics could be promoted by conjoining the learning of ma thematics with the learning of social science topics. Survey instrument was dev eloped to measure student attitudes toward mathematics and social science subje cts and to evaluate student beliefs on learning mathematics embedded in social science topics. Data were collected from high school students in Korea by admi nistering pre- and post-tests: students were intervened with examples of math problems embedded in certain social contexts. The findings indicate that high sc hool students’ experience of solving mathematics problems embedded in social c ontexts positively affects the promotion of their attitudes toward and beliefs on both mathematics and social science subjects.

연명치료 중단기준과 환자관리

김형원 대한외과학회 2019 대한외과학회 학술대회 초록집 Vol.2019 No.5

상용 Gentoo 폴리머가 경화된 고체주입표면에서 물방울 거동

김형원,김정현 한국가시화정보학회 2024 한국가시화정보학회지 Vol.22 No.1

In this study, the behavior of water droplets on a solid-infused surface was evaluated by quantifying a water droplet's contact angle, sliding angle, and terminal velocity. The contact angle hysteresis and sliding angle of water on the solid-infused surface were measured to be lower than those of the hydrophobic PTFE surface. It led to the enhancement of the initiation of the water droplet’s movement. When the capillary number was lower than Ca < 0.004, the terminal velocity of the water droplet on the solid-infused surface was higher than the PTFE surface due to the low contact line resistance. However, the transition of the droplet morphology from a hemispherical shape to a streamlined teardrop shape beyond Ca > 0.004 lost the effect of reducing frictional resistance on the solid-infused surface.

PSF/AS4 복합재료의 가속노화가 피로강도에 미치는 영향

김형원 한국복합재료학회 2006 Composites research Vol.19 No.4

The effects of aging on fatigue of PSF/AS4 laminates was studied using the new energy release rate analysis. The analysis by the variational mechanics has been useful in providing fracture mechanics interpretation of matrix microcracking in cross-ply laminates. This paper describes the changes of the critical energy release rate ΔGmc (microcracking toughness) about the variation of the aging period during fatigue loading. The master plot by modified Paris-law gives a characterization of a material system's resistance to microcrack formation. PSF/AS4 [0/902]s laminates were aged at four different temperatures based on the glass transition temperature for 60 days. At all temperatures, the toughness decreased with aging time. The decrease of the toughness at higher temperature was faster than at lower temperature. To assess the effects of aging on fatigue, the unaged laminates were compared with the laminates which were aged for 60 days at 170°C near 180°C Tg. The slope of dD/dN versus ΔGm of the aged laminates was lower than that of the unaged laminates. There was a significant shift of the aged data to formation of microcracks at the lower values of ΔGm. PSF/AS4 복합재 적층구조의 가속노화가 피로강도에 미치는 영향을 변분이론을 이용한 에너지 발산율(energy release rate) 분석을 이용하여 연구하였다. 변분이론 분석은 수지미소균열에 대한 파괴역학을 해석하는데 사용되어 왔으며 이 논문에서는 피로하중 하에서 가속노화 시간에 따르는 파괴인성이 어떻게 변하는가를 설명하였다. 수정된 Paris 법칙에 의한 선도는 각 재료마다 미소균열이 형성되는 특성을 나타낸다. PSF/AS4 [0/902]s 적층구조가 60일 동안 유리천이온도에 근거를 두고 세분한 4개의 각기 다른 온도로 가속노화를 하였다. 모든 온도에서 파괴인성은 가속노화 시간에 따라 감소하였다. 높은 온도에서의 파괴인성의 감소는 낮은 온도에서의 감소보다 빠르게 진전되었다. 가속노화가 피로강도에 미치는 영향을 파악하기 위해 유리천이온도인 섭씨 180도에 가까운 170도에서 60일 동안 노화한 것과 노화하지 않은 것을 비교하였다. 노화된 시편에 대하여 파괴인성의 변화(ΔGm)가 낮은 값에서 미소균열이 형성되는 것을 알 수 있었다.