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.

S-344 : 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 추계학술대회 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.

고속주축 모니터링용 광파이버 변위센서의 파이버 특성에 따른 센서 성능 연구

박찬규,신우철,배완성,홍준희,이동주 한국공작기계학회 2003 한국공작기계학회 추계학술대회논문집 Vol.2003 No.-

To make high speed spindle system work properly, sensors with outstanding resolution and dynamic characteristics are essential. An optical fiber displacement sensor is based on simple principles. Electrical signal responds to the optical flux change due to the displacement change between a target and a sensor probe. In this paper, the performance of optical fiber displacement sensor has been investigated according to properties of optical fiber. Firstly, optical loss has been measured before and after polishing optical fiber endface. Secondly, allowance of optical fiber bending has been tested. thirdly sensitivity and linear range of the sensor has been found out according to the shape of cross section of optical fiber.

고속주축 모니터링용 광파이버 변위센서의 레이저 다이오드 출력에 따른 성능평가

박찬규,신우철,홍준희,이동주 한국공작기계학회 2004 한국공작기계학회 춘계학술대회논문집 Vol.2004 No.-

This paper is to develop an optical fiber displacement sensor for monitoring high speed spindle. Proper magnitude of optical power as well as amplification of output signal are necessary to improve sensitivity of the sensor. In this paper, to meet the need of improvement of the sensor resolution, we choose proper optical power and amplification level through speculating on optical power of a laser diode.

VII 인자 결핍 신생아에서 발생한 뇌실내출혈 1 례

박형준;김영대;김우경;박용원 인제대학교 2011 仁濟醫學 Vol.32 No.-

Congenital factor VII deficiency is a rare bleeding disorder that has an estimated prevalence of 1/300,000 to 1/500,000. Transmission is autosomal recessive. Because factor VII is important in initiation the coagulation cascade, a factor VII deficiency can result in significant bleeding with pr oiongation of the prothrombin time. In severely affected patients, bleeding starts early in life and encompasses life-threatening hemorrhages such as Intracranial and gastrointestinal hemorrhages. These are the most frequent bleeding events in the first 6 months of life. Definitive diagnosis tests on a specific assay for factor VII clotting activity. Human factor VII from plasma is used to treat factor VII deficiency. Either fresh frozen plasma or factor VII concentrate can be used. We experienced a case of intraventricular hemorrhage in a newborn infant who had been diagnosed as congenital factor VII deficiency. So, we report the case with a review of literatures.

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.

2축 편심축력을 받는 고강도 콘크리트 기둥의 등가응력블럭 수정

박준용,유석형,반병열,신성우 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1(구조계)

The characteristics of stress distribution of non rectangular compressed area in the RC columns are different to those of rectangular compressed area. Nevertheless, in ACI 318-99 code, the design tables for columns subjected to axial loads with bidirectional eccentricities are based on the parameters recommended for rectangular stress block(RSB) of rectangular compressed areas. In this study the characteristics of stress distribution through both angle and depth of neutral axis are observed and formulated rationally. And the modified parameters of rectangular stress block(MRSB) for non rectangular compressed area is proposed. And the computer program using MRSB for the biaxial bending analysis of RC columns in developed and the results of MRSB are compared to RSB and experimental results respectively.