• 제목/요약/키워드: Hwang woo-suk

검색결과 388건 처리시간 0.027초

강우침투시 불포화 무한사면의 안정성 평가 (Stability of unsaturated infinite slope under rainfall-induced infiltration)

  • 송영석;황웅기;이남우;김태형
    • 한국지반공학회:학술대회논문집
    • /
    • 한국지반공학회 2010년도 추계 학술발표회
    • /
    • pp.71-78
    • /
    • 2010
  • The stability analysis of unsaturated infinite slope under rainfall-induced infiltration condition was performed using the generalized effective stress that unifies both saturated and unsaturated condition recently proposed by Lu and Likos(2004, 2006). The Soil-Water Characteristic Curve (SWCC) of the sand with the relative density of 75% was first measured for both drying and wetting processes. The Hydraulic Conductivity Function (HCF) and Suction Stress Characteristic Curve (SSCC) were subsequently estimated. Also, under the rainfall-induced infiltration condition transient seepage analysis of unsaturated infinite slope was performed using the finite element program, SEEP/W. Based on these results, the stability of unsaturated infinite slope under rainfall-induced infiltration condition was examined considering the suction stress. According to the results, the negative pore water pressure and water content within the soil changed with time due to the infiltration. Also, the variation of those caused the variation of suction stress and then the factor of safety of slope changed consequently during the rainfall period.

  • PDF

Agricultural Safety Clothing: Implications for Making and Selecting Clothes

  • Chun, Jong-Suk;Jee, Jung-Woo;Hwang, Kyoung-Sook
    • 대한인간공학회지
    • /
    • 제30권4호
    • /
    • pp.509-515
    • /
    • 2011
  • Objective: The study was performed to suggest factors to consider when making or selecting protective clothing to enhance farmers' health. The purpose of this study was to review and summarize the agricultural safety technology on clothing including hat, gloves, and shoes. Background: The farmers' work clothing has to meet a multitude of requirement. Risk factors in farm-work were identified by previous researches. Agricultural safety clothing needs to be introduced. Method: We reviewed previous papers regarding the agricultural workers' health, safety clothing to protect body from excessive heat and humid environment, ultraviolet(UV) protection, and hazardous body working postures. Also the UV cut effect, pesticideproof clothing, and preventable farm work related musculoskeletal disorders were discussed. Results: The agricultural safety clothing needs to be developed to provide comfort and to be resistant against heat. The UV protection function on skin and eyes has not been fully researched in safety clothing studies yet. Conclusions and Application: The farmers' work-related body posture needs to be studied in order to make and design agricultural safety clothing. The safety issues on agricultural work shoes are also needed to be included in future studies.

다수 마커를 활용한 영상 기반 다중 사용자 증강현실 시스템 (An Image-based Augmented Reality System for Multiple Users using Multiple Markers)

  • 문지원;박동우;정현석;김영헌;황성수
    • 한국멀티미디어학회논문지
    • /
    • 제21권10호
    • /
    • pp.1162-1170
    • /
    • 2018
  • This paper presents an augmented reality system for multiple users. The proposed system performs ar image-based pose estimation of users and pose of each user is shared with other uses via a network server. For camera-based pose estimation, we install multiple markers in a pre-determined space and select the marker with the best appearance. The marker is detected by corner point detection and for robust pose estimation. the marker's corner points are tracked by optical flow tracking algorithm. Experimental results show that the proposed system successfully provides an augmented reality application to multiple users even when users are rapidly moving and some of markers are occluded by users.

직접가압주조한 Al-5%Ni-5%Mg-(Mm)합금의 조직 및 기계적 성질에 미치는 가압력의 영향 (Effect of Pressure on Microstructures and Mechanical Properties in Al-5%Ni-5%Mg-(Mm) Alloy Manufactured by Direct Squeeze Casting)

  • 우기도;정동석;황인오;김석원
    • 한국주조공학회지
    • /
    • 제21권2호
    • /
    • pp.127-134
    • /
    • 2001
  • Misch metal (rare earth element, Ce, La, Nd, Pr) which has large influence on high-temperature stability and toughness was added to the Al-5%Ni-5%Mg alloy, and squeeze casting was used for Al-5%Ni-5%Mg-(Mm) alloys. The effect of applied pressure and misch metal additions on mechanical properties in Al-5%Ni-5%Mg alloy by direct squeeze casting has been investigated. The applied pressure were 0 MPa(gravity casting), 25, 50 and 75 MPa. Squeeze-cast Al-5%Ni-5%Mg-(Mm) alloys had better mechanical properties than those of non-pressurized cast alloys because of the increased cooling rate by the application of pressure during solidification. By the addition of misch metal in Al-5%Ni-5%Mg alloy, better combination of strength and elongation was obtained. The addition of 0.3%Mm in Al-5%Ni-5%Mg alloy improved the heat resistant property due to the formation of fine eutectic phases.

  • PDF

청심연자탕으로 관리한 이명을 동반한 돌발성 난청 치험례 (A Case Study of a Taeeumin Patient with Idiopathic Sudden Sensorineural Hearing Loss that accompanied with Tinnitus who was treated with Cheongsimyeonja-tang)

  • 이미숙;황민우;김윤희
    • 사상체질의학회지
    • /
    • 제23권3호
    • /
    • pp.419-428
    • /
    • 2011
  • 1. Objective: The aim of this study was to report significant improvement of tinnitus and insomnia after treatment with Cheongsimyeonja-tang in a Taeeumin patient with Idiopathic Sudden Sensorineural Hearing Loss(SSHL) that accompanied with Tinnitus. 2. Method: We measured the hearing recovery. For diagnosis on this case, pure tone audiometry was used. The degree of improvement was evaluated by Siegel's Criteria. Visual Analogue Scale(VAS) and Tinnitus Handicap Inventory(THI) were also used to assess tinnitus objectively. 3. Result: There was no improvement in pure tone audiometry by Siegel's Criteria. However, VAS score was decreased from 10 to 1 and THI score was also decreased from 74 to 48. 4. Conclusion: A patient with SSHL, who has little possibility of recovery of hearing loss, was treated with Cheongsimyeonja-tang in a short period and significant improvement in tinnitus and insomnia was observed. We consider that consistent treatment of Cheongsimyeonja-tang can contribute to improve the hearing loss.

관상동맥우회술 중의 경식도 초음파에 의해 발생한 심부감염을 동반한 Pyriform Sinus 천공 - 치험 1예 - (Pyriform Sinus Perforation with Deep Neck Infection Caused by Transesophageal Echocardiography during Coronary Artery Bypass Grafting - A case report -)

  • 장형우;유재석;황호영;김기봉
    • Journal of Chest Surgery
    • /
    • 제42권4호
    • /
    • pp.528-531
    • /
    • 2009
  • 경식도 초음파는 심장수술에서 비교적 안전하게 수술 중 심장의 기능 및 수술 결과를 평가할 수 있어 그 이용이 일반화되고 있으며, 경식도 초음파 관련 합병증은 드물지만 하인두 손상이나 식도 천공 등 위험한 합병증이 생길 수 있다. 폐부종을 동반한 심근경색으로 진단받은 77세 남자환자에서 심폐 바이패스를 사용하 않는 관상동맥우회술 시행 후, 수술 중 경식도 초음파 시술과 관련되어 발생한 것으로 추정되는 pyriform sinus 천공 및 이에 동반된 경부 심부감염을 경험하여 보고하는 바이다.

PLD 및 MOD법으로 제조된 2세대 HTS 선재의 전자기 특성 (Electromagnetic properties of HTS coated conductors fabricated by PLD and MOD)

  • 오상수;황선역;송규정;강석일;하동우;고락길;박찬
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
    • /
    • pp.65-68
    • /
    • 2004
  • A lot of R&D efforts are being concentrated on the development of high performance HTS coated conductors(CC). Unlike the HTS Bi-2223 tape, a variety of processes have been tried to fabricate CC tapes. PLD and MOD are believed to be very effective methods, and high critical currents of long length CC tape have been reported. In this study, we prepared two kinds of YBCO CCs to evaluate electromagnetic property. One is YBCO tape deposited on IBAD template by PLD and the other is AMSC's MOD CC tape Critical current (Ic) in magnetic fields, its angular dependency, and n-value were measured and analyzed. Magnetic field property of Ic was appeared to be different due the fabrication process. MOD tape showed higher in-field property, n-value of both PLD and MOD tapes exponentially decreased with magnetic field. MOD tape showed higher n-value in whole magnetic fields.

  • PDF

초음파 겔화 공정과 초임계 건조 공정을 이용한 다공성 세라믹스 구조체 내부에 실리카 에어로겔 합성 (The Synthesis of Silica Aerogel in the Macroporous Ceramic Structure by Sono-gel Process and Supercritical Drying Process)

  • 홍선욱;송인혁;박영조;윤희숙;황기영;이영우
    • 한국세라믹학회지
    • /
    • 제47권6호
    • /
    • pp.553-559
    • /
    • 2010
  • The synthesis behavior of nanoporous silica aerogel in the macroporous ceramic structure was observed using TEOS as a source material and glycerol as a DCCA(dry control chemical additive). Silica aerogel in the macroporous ceramic structure were synthesized through a sono-gel process. The wet gel in the macroporous ceramic structure were aged in ethanol for 72 h at $50^{\circ}C$. The aged wet gel was dried under supercritical drying condition. The addition of glycerol has a role of giving the uniform pore size distribution. The reproducibility of aerogel in the macroporous ceramic was improved in the glycerol(0.05 mol%) added to the silica sol and TEOS : $H_2O$=1 : 12.

Electrical Characteristic Changes of ZnO Varistors by Energy Absorption

  • Kim, Woo-Hyun;Hwang, Seong-Cheol;Wang, Guoming;Kil, Gyung-Suk;Ahn, Chang-Hwan
    • 한국전기전자재료학회논문지
    • /
    • 제30권12호
    • /
    • pp.817-821
    • /
    • 2017
  • As a ZnO varistor is subjected to electrical and environmental stresses, it degrades gradually, which may result in power interruption by short circuit. This study investigates changes in the electrical characteristics of ZnO varistors due to deterioration owing to energy absorption, and determines the optimal parameters for on-line diagnosis of the varistor. Two types of varistors were used for an accelerated aging experiment involving the application of the $8/20{\mu}s$ standard lightning impulse current. The electrical characteristics in terms of the reference voltage, total leakage current, resistive leakage current, and third-harmonic component of the total leakage current were measured, and their change rates were analyzed. The results revealed that the total leakage current increased slightly with an increase in the varistor absorbed energy, while the resistive leakage current and the third-harmonic component increased apparently. Therefore, the third-harmonic component of the total leakage current was proposed as the optimal parameter for on-line monitoring of ZnO varistor conditions.

도적강기탕(導赤降氣湯)으로 호전된 크론병 환자 1례 (A Case Study of a Soyangin Patient with Crohn's Disease who Reported Symptomatic Improvement after Being Treated with Dojeokgangki-tang)

  • 이미숙;황민우;김윤희
    • 사상체질의학회지
    • /
    • 제24권2호
    • /
    • pp.61-70
    • /
    • 2012
  • 1. Objectives : The aim of this study was to report significant improvement of chronic diarrhea and hematochezia after treatment with Dojeokgangki-tang in a Soyangin Patient with Crohn's Disease. 2. Methods : The patient's subjective and objective symptoms were observed daily throughout the hospitalization period, and the Crohn's disease activity index(CDAI) was calculated to gauge the progress or lack of progress. 3. Results : The symptoms of diarrhea and hematochezia disappeared by the end of the hospitalization period without recurrence, and the CDAI score dropped from 92.5 to 47. 4. Conclusions : A patient with Crohn's disease, who was in the state of repetitive relapse and remission after long term clinical courses was treated with Dojeokgangki-tang in a short period and the the symptoms of diarrhea and hematochezia disappeared without recurrence. Then the patient could stop taking corticosteriods and taper off immune-suppressing drugs.