9-12%Cr강의 첨가원소 및 열처리에 따른 미세조직거동과 경도변화

주성욱,유정훈,신기삼,허성강,이재현,석진익,김병훈,김정태 국립7개대학공동논문집간행위원회 2004 공업기술연구 Vol.4 No.-

9-12%Cr steel are getting increasing attention for expanded application as high temperature materials applicable for gas turbine compressors, steam turbine rotors, blade and casing. For efficient and extensive application of 9-12%Cr steel, the data in addition to the improvement of mechanical properties on the correlation of microstructural evolution and mechanical properties are inevitable and thus the investigation in this study is performed for the determination for the specimens heat-treated at 600, 650 and 700℃ for 1000, 3000 and 5000hrs. The microstructure of as-received specimen was tempered martensite, with a high dislocation density and secondary phases. Upon high temperature heat-treatment, the martensite lath got larger and dislocation density decreased resulting the reduction of the strength. In addition, sharp growth of secondary phases was observed in the specimen heat-treated at 700℃ for 5000hrs. A specimen aged at 600℃ and 650℃ Laves phase was observed. The hardness showed close relationship with the secondary phase particle and dislocation density.

Development of a Chest‑Belt‑Type Biosignal‑Monitoring Wearable Platform System

Joo‑Hyeon Lee,Hyun‑Seung Cho,Jin‑Hee Yang,Sang‑Min Kim,Jeong‑Whan Lee,Hwi‑Kuen Kwak,Je‑Wook Chae 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.4

The purpose of this study was to develop a wearable platform system that can detect and acquire a soldier’s biosignals (i.e., heart activity signal, respiration rate, etc.) in a nonrestrained, unconscious manner. These detected biosignals are transmitted to a processing device to analyze and monitor the soldier’s physical status. To achieve this, textile-based heart activity electrodes and a strain gauge sensor for the respiration signal measurement were developed, and their performances in detecting each signal were verifed. These sensors were embedded in a chest belt to design a wearable platform that can simultaneously measure heart activity and respiration signals. The sensor part of the chest belt has a dual layer structure to detect high-quality signals. Stretch fabric was used on the outer layer and a respiration sensor was attached to the belt. On the inside layer, a non-stretch fabric was used as the base fabric and a heart activity-sensing electrode, that is capable of taking measurements using a modifed lead-II heart activity signal induction method, was embroidered onto the fabric. Subjects were asked to wear the chest belt, and a biosignal processor module was attached to verify the system’s performance while simultaneously acquiring the heart activity and respiration signals. More specifcally, it was confrmed that the two signals were detected in a stable. It is expected that the biosignal-monitoring wearable platform system developed in this study will be able to efectively analyze and monitor soldiers’ biosignals.

오원천의 식물플랑크톤 군집에 대한 연구

주현수,김진,박종천,정원석,송현철,이용탁,이우범 國立麗水大學校 環境問題硏究所 2004 環境硏究論文集 Vol.6 No.-

We carried out a study on phytoplankton community at Owon stream, Jeollabukdo, Korea. The author have examined 83 taxa of the phytoplankton from researched area. These were composed of 5 classes, 11 orders, 21 families, 44 genera, 79 species, and 9 varieties. The composition of occurrence species were as follows: green algae are 48.2%, diatoms are 33.7%, blue green algae are 10.8% and etc(7.3%). Dominant species were Chlamydomonas angulosa, Pandorina morum, Coelastrum microporum, Scenedesmus quadricauda, Staurastrum gracile, Melosira varians, Me. italica, Synedra ulna, Sy. acus, Cocconeis placentula, and Cymbella tumida. The standing crops varied from 1,650cells/ℓ to 47,000cells/ℓ. Phytoplankton density of Owon stream were lower about 8.6 times to a 1,531 times than those of other lakes and rivers in Korea. So, to preserve the water quality in Owon stream we have to manage continuously on the nitrogen and phosphorus.

노인들의 생활체육참가가 건강체력과 행복감에 미치는 영향

전종옥,함주현,박승한 한국스포츠리서치 2003 한국 스포츠 리서치 Vol.20 No.1

The purpose of this study was to how the sports for all participation the effect on health fitness and happiness of in elderly. This study is with selected in 20 sport for all of participation people 20, not participation 20. The measurement items were sit and reach, 800M, body fat %, grip strength and happiness. The data statistics was applied by one-way ANOVA in SpssWin8.0. The result are as follows; 1. There were statistically significant difference between the grip strength, 800M, body fat % and sit and reach means of the control group and the experimental group. 2. The happiness was participation people higher than gruop not participation

재발성 류마티즘 환자에서 발작의 유발인자

주유철,이동민,양종태,신병철,임태영,서정균,정기영,최동헌,김원,조영신,고희관 조선대학교 2001 The Medical Journal of Chosun University Vol.26 No.2

Background and Objectives : Palindromic rheumatism (PR) is known to be triggered without any obviously inciting events in most patients, although, in a few cases, attacks have been noted to relate to another events such as weather change, childbirth, ingestion of certain foods, or over-exercise. The aim of this study was to characterize the triggering factors on palindromic attacks. Materials and Methods : We evaluated sixty-four patients with PR for the presence of triggering factors and the relationship between attacks and triggering factors by interview of patients. We considered that there was an probable association between episodes and PR, if episodes within 24 hours prior to PR had triggered at least 50% of all attacks and a definite association between episodes and PR, if episodes within 24 hours prior to PR had triggered 100% of all attacks. Results : In 15 patients (35.9%), there was a possible association between episodes of PR and initiating events. In 8 patients (12.5%), there was a definite association between episodes of PR and initiating events. The triggering factors were physical over-activity including exercise (19/64: 29.7%), foods, such as rawfish, crab, and chicken, including alcohol (19/96: 19.8%). However, there were no difference between the groups with and without the triggering factor in sex ratio, duration and onset of PR, the positive rate of rheumatoid factor and involved sites. Conclusion : Our observations showed that PR was triggered by physical over-activity more than in previous reports and hypersensitivity to foods was a causative factor in some patients with PR. However, patients with triggering factors had a similiar clinical profile to patients without triggering factors.

Schiff Base에 의한 구리 부식 억제

정병구,이현석,장영학,문채주 木浦大學校 應用科學硏究院 2001 應用科學硏究誌 Vol.1 No.-

The inhibiting action of copper in 5% hydrochloric acid(HCI) solutions with or without Schiff base, 1,2-bis(naphthylideneimine)ethane(NET), 1,3-bis(naphthylideneimine) propane(NPR), 1,4-bis(naphthylideneimine)butane(NBU), and 1,5-bis(naphthylideneimine) pentane(NPE), has been studied by the Tafel method and AC impedance technique. The corrosion parameters were obtained at different inhibitor concentrations and the temperature effect was also investigated. The inhibiting efficiency increases with a decrease in temperature or increase in concentration of the Schiff base. NPE is the best inhibitor in this series and the maximum inhibition efficiency at a concentration of 5×10^-4 M at 298 K approached 90.07%. Schiff base with longer-chain are superior to shorter-chained analogues in inhibition efficiency.

노인과 대학생의 낙상 위험 분석

정다현,김예희,김지은,이예영,강현주 순천향대학교 기초과학연구소 2021 순천향자연과학연구 논문집 Vol.27 No.1.2

The purpose of this study was to analyze risk of falls between elderly people and college students. The subjects of this study were 25 people aged 70 years or older and 17 college students located in Asan. We measured sensory, integrated balance, nervous, musculoskeletal system and HQR by FRA system (Inbody, Korea). The results of measurement showed significant differences in sensory system (p<.01), integrated balance (p<.001), nervous system (p<.001), and musculoskeletal system (p<.001) between groups. These results suggest that aging makes difference of function of these systems. In our view, counterplans need to be implemented, including exercise intervention to prevent decreases of fall risk,

소화성 궤양 환자에 대한 염산 베넥세이트(울굿^(�)) 임상 효과

정현용,육은주,이헌영,노홍구,김영건 최신의학사 1993 最新醫學 Vol.36 No.8

만곡 근관에서 삼각 혹은 장방형 단면 구조의 니켈-티타늄 파일 응력 분포에 관한 3차원 유한요소 연구

김현주,이찬주,김병민,박정길,허복,김현철 대한치과보존학회 2009 Restorative Dentistry & Endodontics Vol.34 No.1

이 연구의 목적은 3차원 유한요소 모형 분석을 이용하여 삼각 대칭형과 S형태의 단면 및 변형된 사각 형태인 장방형 단면으로 분류되는 네 종류의 니켈티타늄 파일이 만곡 근관 적용 시의 응력 분포를 비교하는 것이다. 삼각 대칭형 단면 구조의 ProFile #30 / .06과 HeroShaper #30 / .06,장방형 단면구조의 Mtwo #30 / .05와 NRT #30 / .06 파일을 마이크로컴퓨터 단층촬영을 하고 reverse engineering을 통하여 파일의 구조를 얻고 삼차원 유한요소모형을 제작하였다. 모형 근관 내에서 파일이 근관장 끝까지 진입하여 회전할 때 발생하는 von Mises 응력 분포 및 파일의 제거후의 잔류 응력의 분포양상을 ABAQUS 프로그램을 이용하여 비교하였다. 근관 내 회전 시에 발생하는 응력을 관찰하였을 때 NRT 파일에서 가장 큰 응력을 나타냈으며 , 각 파일에서의 최고 응력과 최저 응력을 비교하였을 때 Mtwo파일에서 가장 큰 차이가 나타났다. 응력의 내부 분포 경향을 보았을때 장방형 구조의 단면을 가진 Mtwo 및 NRT 파일에서 불연속적인 응력의 집중 부위가 관찰되었으며 , 근관 외부로 파일을 제거하여 탄성 회복이 일어난 후의 잔류 응력도 NRT 파일에서 가장 높게 나타났다. 이상의 결과로 유추할 때, 삼각대칭 단면 구조를 가진 파일보다 S-형태의 단면과 변형된 사각 형태의 단면 등의 장방형 단면 구조의 파일이 파절의 위험성이 더 클 것으로 사료된다. The purpose of this study was to compare the stress distributions of NiTi rotary instruments bascd on their cross-sectional geometries of triangular shape-based cross-sectional design. S-shaped cross-sectional design and modified rectangular shape-based one using 3D FE models. NiTi rotary files of S-shaped and modified rectangular design of cross-section such as Mtwo or NRT showed larger stress change while file rotation during simulated shaping. The stress of files with rectangular cross-section design such as Mtwo, NRT was distributed as an intermittent pattern along the long axis of file. On the other hand, the stress of files with triangular cross-section design was distributed continuously. When the residual stresses which could increase the risk of file fatigue fracture were analyzed after their withdrawal, the NRT and Mtwo model also presented higher residual stresses. From this result, it can be inferred that S-shaped and modified rectangular shape-based files were more susceptible to file fracture than the files having triangular shape-based one.

상아모세포 관련 유전자, OD314의 발현과 기능 연구 : OD314

김두현,김흥중,정문진,손호현,박주철 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.4

Odontoblasts are responsible for the formation and maintenance of dentin. They are known to synthesize unique gene products including dentin sialophosphoprotein (DSPP). Another unique genes of the cells remain unclear. OD314 was isolated from the odontoblasts/pulp cells of rats and partially characterized as an odonto-blast-enriched gene (Dey et al., 2001). This study aimed to elucidate the biological function of OD314, relating to odontoblast differentiation and dentinogenesis. After determining the open reading frame (ORF) of OD314 by transient transfection analysis using green fluorescent protein (GFP) expression vector, mRNA in-situ hybridization, immunohistochemistry, reverse transcription-polymerase chain reaction (RT-PCR) and western analysis were performed. The results were as follows: 1. In in-situ hybridization, OD314 mRNAs were expressed in odontoblasts of developing coronal and root pulp. 2, OD314 was a novel protein encoding 154 amino acids, and the protein was mainly expressed in cyto-plasm by transient transfection analysis. 3. Mineralized nodules were associated with multilayer cell nodules in the culture of human dental pulp cells and first detected from day 21 using alizarin-red S staining. 4. In RT-PCR analysis, OD314, osteocalcin (OC) and DSPP strongly expressed throughout 28 days of culture. Whereas, osteonectin (ON) mRNA expression stayed low up to day 14, and then gradually decreased from day 21. 5. Western blots showed an approximately 17 kDa band. OD314 protein was expressed from the start of culture and then increased greatly from day 21. In conclusion, OD314 is considered as an odontoblast-enriched gene and may play important roles in odontoblast differentiation and dentin mineralization.