Effect of Impact Velocity on Interface Characteristics of HT‑9 Steel Joints Fabricated by Magnetic Pulse Welding

Jun‑Woo Song,Jin‑Ju Park,Gyoung‑Ja Lee,Min‑Ku Lee,Kyu‑Hyun Park,Soon‑Jik Hong,Jung Gu Lee 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.3

The weldability window in magnetic pulse welding (MPW) is proposed for the end-closure joining of HT-9 steel tubularworkpieces. Based on both theoretical and experimental investigations, the impact velocity of the flyer tube at the momentof collision had a dominant effect on the bonding characteristics of the resultant joints and the optimal impact velocity wasestimated to be in the range of 265–290 m/s in this alloy system. Under the optimal process conditions, no leak was detectedduring helium leak testing. Moreover, the integrity of the joint interface was preserved until the tube section ruptured duringinternal pressure burst testing. For HT-9 steel, the ductile δ-ferrite phase produced by the localized interfacial melting duringMPW acted as an effective obstacle to crack propagation, thereby enhancing the fracture resistance of the joint interface. Allof the results demonstrated the high integrity and durability of the HT-9 steel tube assembly fabricated by the MPW process.

백서의 치아이동 시 피질골 천공이 치주조직의 OPG, RANK, RANKL의 발현에 미치는 영향

박우경,김성식,박수병,손우성,김용덕,전은숙,박미화 대한치과교정학회 2008 대한치과교정학회지 Vol.38 No.3

치아이동 시 피질골 천공이 치조골 재형성에 미치는 영향을 알아보기 위해서 생후 15주된 자성백서를 사용하여 피질골 천공 후 치아이동을 실시한 실험군(Tooth movement with cortical punching: TMC group, n = 16)과 교정적 치아이동만 실시한 대조군(Tooth movement only group: TM group, n = 16)의 치아주위조직을 면역조직화학염색을 통하여 관찰하였다. 실험군과 대조군의 실험동물에 20 gm의 힘으로 상악 전치부 사이를 이개시키는 치아이동을 시행하였으며 실험군에서는 상악 전치부 구개부위에 피질골 천공을 실시하였다. 치아이동 후 1, 4, 7, 14일째에 실험군과 대조군의 실험동물을 희생시켰다. 면역조직화학염색법으로 OPG, RANK, RANKL의 발현을 비교한 결과, OPG의 발현은 양 군 모두에서 미처치 대조군에 비하여 감소되었으나, 실험군에서의 발현이 대조군보다 컸으며, RANK, RANKL은 피질골 천공을 시행한 경우에 더 강한 발현을 보이는 것이 관찰되었다. 따라서 피질골 천공이 치주조직의 OPG, RANK, RANKL의 발현에 영향을 미치며 치조골의 재형성을 향상시키는 것을 알 수 있었다. Objective: The purpose of this study was to investigate whether cortical punching could stimulate the expression of OPG, RANK, and RANKL during tooth movement by immunohistochemistry. Methods: 34 sprague-dawley rats (15 weeks old) were allocated into 3 groups: TMC group (experimental group; Tooth Movement with Corticotomy, n = 16), TM group (control group; Tooth Movement only group, n = 16), and non-treatment group (n = 2). 20 gm of orthodontic force was applied to rat incisors by inserting elastic bands. The duration of force application was 1, 4, 7 and 14 days. A microscrew (diameter 1.2 mm) was used for cortical punching of the palatal side of the upper incisors in the TMC group. Results: Distributions of OPG, RANK, and RANKL were evaluated by immunohistochemistry. OPG, RANK and RANKL were observed on experimental and control groups. On the compression side, the degree of the expression of OPG decreased in both groups. The expression of RANK was most prominent in the experimental group of day 4. The expression of RANKL was most intensive and extensive in the experimental group of day 7. However, the expression of OPG was decreased in the experimental and control groups compared to the non treatment group. The expression of OPG, RANK and RANKL after force application were decreased at day 14. Conclusions: These findings suggested that cortical punching might stimulate remodeling of alveolar bone during a 2 week period of tooth movement without any pathologic change.

The Role of Skeletal Muscle Mass in Development of Metabolic Syndrome

( Byung Sam Park ),( Jun Sung Moon ),( Ji Sung Yoon ),( Kyu Chang Won ),( Hyoung Woo Lee ) 대한내과학회 2013 대한내과학회 추계학술발표논문집 Vol.2013 No.1

Introduction: It has been well known that abdominal adiposity is related with insulin resistance and greater risk of metabolic disorder. Skeletal muscle plays central role in insulin mediated glucose disposal of whole body, but we only know a little about the association between skeletal muscle mass and MetS (MetS). The aim of this study is to clarify the clinical role of skeletal muscle mass in developing MetS through using skeletal muscle parameters by body impedance analysis (BIA). Methods: 1,042 healthy adults aged from 20 to 75 years who visited Yeungnam university health promotion center from Jun. 2008 to Jun. 2010 were enrolled. 204 subjects who had prior MetS or chronic disease that can affect to skeletal muscle mass were excluded. After 24 months from baseline, the metabolic parameters were assessed and the development of MetS was diagnosed using modified NCEP-ATP III criteria. From the BIA (Inbody 720), we obtained skeletal muscle mass (SMM, Kg), body fat mass (BFM, Kg), and visceral fat area (VFA, cm2). Then, we had defined as follows; percent of skeletal muscle mass (SMM%, %): SMM (kg)/weight (Kg), skeletal muscle index (SMI, Kg/m2): SMM (Kg)/height (m)2, skeletal muscle to body fat ratio (MFR): SMM (kg)/BFM (Kg) and skeletal muscle to visceral fat ratio (SVR, Kg/cm2): SMM (Kg)/VFA (cm2) Results: Mean follow up periods were 28.7±5.4 months. Among total 838 subjects (46.9±9.9 years, M:F=477:361), 88 (10.5%) were newly diagnosed MetS. 5th quintile of the SMM%, MFR and SVR was associated with decreased risk of development of MetS after adjusting for confounding factors. Conclusion: Decreased skeletal muscle mass may play critical role in development of the MetS and not absolute amount of skeletal muscle mass but relative ratio to body composition may be more important.

한국 정신장애의 역학 조사 연구[I] : 각 정신장애의 유병률

조맹제,함봉진,김장규,박강규,정은기,서동우,김선욱,조성진,이준영,홍진표,최용성,박종익,이동우,이기철,배재남,신정호,정인원,박종한,배안,이충경 大韓神經精神醫學會 2004 신경정신의학 Vol.43 No.4

Objectives : This study aims to estimate the prevalence of the DSM-IV psychiatric disorders in Korean population using the Korean version of Composite International Diagnostic Interview (K-CIDI). Methods : Subjects were selected by taking multi-stage, cluster samples of 7,867 adult household residents, 18 to 64 years of age, in ten catchment areas. Total 78 trained interviewers administered the K-CIDI to the selected respondents, from June 1 to November30,2001. Results : Total 6,275 respondents completed the interview. Some 33.5% of respondents reported at least one lifetime disorder, 20.6% reported at least one-year disorder, and 16.7% reported at least one-month disorder. The most common lifetime disorders were alcohol abuse/dependence (17.24%), nicotine dependence/withdrawal (11.19%), specific phobia (5.16%), and major de-pressive disorder (4.25%). The lifetime prevalence of substance abuse/dependence (0.25%) and schizophrenia (0.16%) was very low. Nicotine and alcohol use disorder showed very high male/female ratio. Mood disorder and anxiety disorder were more prevalent among female than male. Conclusion : The prevalence of psychiatric disorders was high. In comparison with other studies, remarkable differences in distributions of psychiatric disorders across the areas and times were observed.

제 3 대구치 발치시 환자의 호흡 패턴이 스트레스 변화 양상에 미치는 영향

이상명,김형욱,박양호,김진철,박준우,이성준,안재목,Rhee, Sang-Myung,Kim, Hyung-Wook,Park, Yang-Ho,Kim, Jin-Cheol,Park, Jun-Woo,Rhee, Sung-Jun,Nyamdorj, Selenge,Ahn, Jae-Mok 대한구강악안면외과학회 2007 대한구강악안면외과학회지 Vol.33 No.5

Purpose: Heart rate variability(HRV) is the clinical consequence of various influences of the autonomic nervous system(ANS) on heart beat. HRV can estimate the potential physiologic rhythm from the interval between consecutive beats(RR interval or HRV data). It is known as RSA which represents respiration-related HR rhythmic oscillation. Previous studies demonstrated a specific breathing pattern(0.1Hz, 6breaths/min) to improve a physiological body condition related to the stress. In this paper, the level of stress would be evaluated in terms of three phases of the dental treatment, combined with 6breaths/min. Methods: These phases include before, during and after tooth extraction or anesthesia or something.36 patients' stresses were assessed using HRV stress analyzer in each phase in Kangdong Sacred Heart Hospital, and Chuncheon Sacred Heart Hospital, Hallym University Medical Center from Jun. to Sept. of 2007. HRV 5-min data collected were analyzed in time-domain and frequency-domain to evaluate the activity of autonomic nervous system(ANS) which represents the level of stress. Results: All HRV parameters including HF(high frequency), LF(low frequency) and LF/HF ratio showned a significant change affecting the ANS balance. There was a 6.4% difference between R(LF/HF)s on general breathing pattern for balance of Autonomic nervous system, but on controlled breathing pattern, 0.1Hz, was made narrow till 1.4%. The activity of ANS has increased by 1.4% on general breathing pattern, and by 2.9% on controlled breathing pattern, 0.1Hz. Conclusion: After analysis of preoperative stress changes and effect of breathing pattern of 0.1 Hz on the stress in 36 patients who have undergone third molar extraction, following was concluded. In the preoperative stage, the sympathetic change was the greatest?after the?anesthetic injection, and stress was relieved by controlling the breathing pattern to a frequency of 0.1Hz.

태권도선수의 호흡순환능력에 관한 연구

박철호,김영준,김우규,박태열,홍명엽 東亞大學校附設스포츠科學硏究所 1999 스포츠科學硏究論文集 Vol.17 No.-

The purpose of this study was to evaluate the anaerobic thresold and EPOC(Excess post-exercise Oxygen Consumption) in treadmill exercise of taekwondo players(n=7),and group of controls college students(n=7). The started treadmill exercise with speed of 120m/min and within treadmill 5% slope. Especially the treadmill speed was increased with 20m/min per two minutes and subjects were finally led to exhaustion. The results obtained from this test were as follows: 1. The VO₂max( /min), VO₂ max(kg) showed significantly higher differences taekwondo group than control group in maximum exercise. 2. The ventilation volume showed significant difference taekwondo group than control group in maximum exercise. 3. The anaerobic threshold showed significant difference taekwondo group than control group in maximum exercise. 4. The EPOC showed significant difference taekwondo group than control group in maximum exercise.

남강댐 유역에서의 HEC-HMS 모형의 적용성

박준일,신형우,조봉철,장영태 경상대학교 생산기술연구소 2000 生産技術硏究所論文集 Vol.16 No.-

In order to find out the runoff characteristics in Nam River Dam basin, hydrological data such as rainfall, water level, and discharge, have been collected and measured. Using the collected and measured data for the study area during 1990-1999, hydrological parameters were estimated. The HEC-HMS(Hydrologic Modeling System) model was used to review the applicability of flood hydrographs and the results of simulation were compared to the observed data and Stroge Function Method for several flood hydrographs in this study. From the results of analysis, the following conclusions were obtained: First, the HEC-HMS model showed better results for the capabilities of regenerating flood hydrographs Second, the fluctuation shape of flood hydrographs for the rainfall distribution concentrated on head have been shown peak time to be relatively short for other rainfall distribution. Third, for forecasting and warning of flood occurrence in future, it is necessary that the existing hydrological data were made good and hydrological data were accumulated more. Also, using the HEC-HMS model to complement the Storage Function Method, it is possible that forecasting and warning flood occurrence is progressive in Nam River Dam.

지리적표시의 다자등록시스템에 관한 연구 : 상표법 개정안의 보완사항의 제안

朴濬佑 한국기업법학회 2004 企業法硏究 Vol.16 No.-

The topic of this article is 'multilateral registration system of geographical indications (hereinafter multilateral registration system).' There have been debates on the subject between European countries and the rest of the world. The core issue is the legal effects of the registration on the participating parties. European countries want a binding effect, while the rest of the world want a non-binding one. After introducing the debates in the WTO, I argued that whichever result would come out, Korea should make a strong registration system for geographical indications in order to promote agricultural and fishery industries in Korea. Finally, I made some suggestions for the draft amendment of Korea Trademark Act for the registration of geographical indications.

마이크로 공장을 위한 디지털 생산 시뮬레이션

박상호,정영상,송준엽,이승우,김동훈,이수훈,박종권 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

Existing manufacturing system has consumed too much energy, space and resource in micro parts manufacturing. To improve this, micro factory system is suggested. But it is difficult to get the high reliability in the assembly, production and inspection of the minute parts because the construction of the micro factory has been started just before. In this study, we will build the digital manufacturing simulation on the micro factory's process and verify the production and assembly process using this simulation.

3차원 비디오 자동 동작분석 시스템 개발

박성순,양창수,장준원,이경일,우철호,백승국 한국운동역학회 1998 한국운동역학회지 Vol.8 No.2

The purpose of this study was to develope both hardware and software of automatic 3-dimensional video motion analysis system. In this image capture system, the vedeo image was stored as a file in CD-Rom directly, the refore it was possible to analyze motion without VCR. Reflective markers were used to digitize automaticaly. C-language and MS-Visual Basic 5.0 ] anguage were utiliged in this software to analyze motion. The conclusions were as follows; 1. The vedeo information at sixty frames per second could be captured accurately as a image with a resolution photography of 640×480-24 bit. 2. It was possible to digitize both manually and automatically utilizing reflective marks attached the body. 3. The automatic 3-dimensional video motion analysis system, which was developed in this study not only increased accuracy but also reduced digitizing time so much.