• Title/Summary/Keyword: 조기 강도

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Field Applicability Evaluation Experiment for Ultra-high Strength (130MPa) Concrete (초고강도(130MPa) 콘크리트의 현장적용성 평가에 관한 실험)

  • Choonhwan Cho
    • Journal of the Society of Disaster Information
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    • v.20 no.1
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    • pp.20-31
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    • 2024
  • Purpose: Research and development of high-strength concrete enables high-rise buildings and reduces the self-weight of the structure by reducing the cross-section, thereby reducing the thickness of beams and slabs to build more floors. A large effective space can be secured and the amount of reinforcement and concrete used to designate the base surface can be reduced. Method: In terms of field construction and quality, the effect of reducing the occurrence of drying shrinkage can be confirmed by studying the combination of low water bonding ratio and minimizing bleeding on the concrete surface. Result: The ease of site construction was confirmed due to the high self-charging property due to the increased fluidity by using high-performance water reducing agents, and the advantage of shortening the time to remove the formwork by expressing the early strength of concrete was confirmed. These experimental results show that the field application of ultra-high-strength concrete with a design standard strength of 100 MPa or higher can be expanded in high-rise buildings. Through this study, we experimented and evaluated whether ultra-high-strength concrete with a strength of 130 MPa or higher, considering the applicability of high-rise buildings with more than 120 floors in Korea, could be applied in the field. Conclusion: This study found the optimal mixing ratio studied by various methods of indoor basic experiments to confirm the applicability of ultra-high strength, produced 130MPa ultra-high strength concrete at a ready-mixed concrete factory similar to the real size, and tested the applicability of concrete to the fluidity and strength expression and hydration heat.

Medical Information Event Monitoring System based on Sense and Respond (Sense and Respond 기반의 의료정보 이벤트 모니터링 시스템)

  • Kang, Un-Gu;Lee, Young-Ho;Kim, Si-Ra;Yoon, Young-Mi
    • The Journal of the Korea Contents Association
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    • v.9 no.8
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    • pp.138-146
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    • 2009
  • Recently big-sized hospitals showed their interest in medical information event monitoring system based on Sense and Respond in order to give patients in emergency a safer medical treatment. In this paper we implemented medical information event monitoring system based on Sense and Respond which stand on event and monitoring process. This system consists of event definition, event extraction, event delivery, and monitoring. It ensures real-time response by grasping and delivering medical information in real-time, and well-balanced understanding of information for hospital management by real-time tracking. Also early confrontation case by case by, event delivery make the safety of patients be secured, the efficiency of hospital can be maximized by early grasping the problems in hospital management problems.

Development and Application of an Early Exercise Program for Open Heart Surgery Patients (개심술 환자를 위한 조기 운동프로그램의 개발 및 적용에 관한 연구)

  • Ha, Yi-Kyung;Jung, Yoen-Yi
    • Journal of Korean Critical Care Nursing
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    • v.4 no.1
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    • pp.65-73
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    • 2011
  • Purpose: This study was to develop and evaluate stability and effects of an early exercise program for patients with open heart surgery. Methods: The subjects of this study were 30 patients who had either a coronary bypass surgery or a valvular heart surgery at a tertiary hospital in Seoul. The data was collected by observation and measurement from October 1, 2004 to November 15, 2004. Results: The early exercise program developed for this study consisted of range of motion exercise and walking. Intensity of walking was 1~3 METs and increased progressively to daily target distance. During exercise, the subjects were monitored heart rate, blood pressure and RPE (Rating of Perceived Exertion). The mean FIM (Functional Independent Measurements) score of subjects was significantly improved after the early exercise program. However, several complaints such as dizziness or pain were also reported. Most complaints were associated with chest tube and RPE. Conclusion: The early exercise program can help to recover patients' physical activities after surgery, and can be applied to most patients. Patients' RPE, dizziness and pain was possible limitations, therefore, active pain control and prevention of accidents for patients would be needed.

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Design and analysis of an X-switch optical modulator (X-스위치 광변조기의 설계 및 분석)

  • 소대화;강기성;채기병;장용웅
    • Electrical & Electronic Materials
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    • v.4 no.3
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    • pp.249-258
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    • 1991
  • He-Ne레이저(.lambda.=0.6328[.mu.m])를 광원으로 사용하는 y-cut LiNbO$_{3}$기판의 광 도파로 형성 과정을 빔 전송방식 메카니즘을 이용하여 광 도파로에서 광파의 전계 변화 및 전계 분포에 대하여 시뮬레이션 하였다. 그리고 Xl(55[.mu.m])* Zl(5000[.mu.m])인 LiNbO$_{3}$기판의 광 도파로 폭을 4[.mu.m], 버퍼층을 0.02[.mu.m]로 하였을때 도파로 층의 깊이가 0.2[.mu.m]인 지점에서 인가전압에 대한 x방향의 전계(E$_{x}$)와 y방향의 전계(E$_{y}$ )분포를 관찰하였다. 또한 단일 도파로의 파라미터 조건을 적용하여 X-스위치를 구성하였을때 전계를 인가하지 않은 상태에서 굴절율 변화(dn) 0.002, 도파로 폭(w) 3[.mu.m]로 하여 도파로의 교차각(.alpha.)을 0.4.deg.~0.6.deg.로 변화시킨 경우, .alpha.=0.5.deg.와 0.6.deg.일 때는 광빔이 bar측으로 출력되었고 .alpha.=0.4에서는 광빔이 cross측으로 출력 됨을 확인하였다. 따라서 위에서 확인된 도파로의 교차각 .alpha.=0.4.deg.인 경우, 전극간격(gap)이 2[.mu.m]인 조건에서 스위칭 전압을 인가하였을 때 25[V]에서 전기광학 효과에 의하여 광빔이 cross측에서 bar측으로 변조됨을 확인함으로써 X-스위치 광변조기의 기본적인 설계조건을 구현하였다.

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A Case of Scrotal Swelling Induced by Tunica Vaginalis Abscess (고환초막강의 농양에 의한 음낭 부종 1례)

  • Kim Jong-Hoon;Lee Dong-Keun;Lim In-Seok
    • Childhood Kidney Diseases
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    • v.7 no.1
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    • pp.103-105
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    • 2003
  • Scrotal swelling may be acute or chronic, painful or painless. Common causes of scrotal swelling in newborns are hydrocele, inguinal hernia, testicular torsion, testicular tumor, scrotal hematoma, meconium peritonitis and epididymitis. Abrupt onset of a painful scrotal swelling necessitates prompt evaluation. Testicular torsion and incarcerated inguinal hernia require urgent surgical management. We report a case of scrotal swelling caused by a tunica vaginalis abscess in a 20-days-old boy. He was admitted to the hospital due to fever, irritability and left scrotal swelling with local heat, tenderness and redness. Exploratory laparotomy was performed to rule out testicular torsion. On the operative field, congestive erythematous inflammation on the left tunica vaginalis was noted and it was filled with a pus like discharge. The cultured organism was Streptococcus agalactiae(group B). He recovered quickly after debridement and administration of empirical antibiotics.

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Enzyme-Linked Immunosorbent Assay(ELISA) for the Rapid Detection of the Flacherie Virus Disease (효소항체법에 의한 누에 바이러스성 무름병의 진단)

  • Gang, Seok-U;Kim, Gwon-Yeong;Gang, Seok-Gwon
    • Journal of Sericultural and Entomological Science
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    • v.34 no.1
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    • pp.35-40
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    • 1992
  • An enzyme-linked immunosorbent assay (ELISA) was studied for the rapid diagnosis of the flacherie virus (FV) of the silkworm, Bombyx mori. The optimised concentration of rabbit anti-FV IgG and enzyme conjugate for the this technique were 15$\mu\textrm{g}$/$m\ell$ and 1:100 dilution, respectively. In ELISA, the detectable concentation of purified FV was 15ng/$m\ell$, and the flacherie viral antigens in the larval extracts were detected as early as 24 hours after the experimental infection. The results indicated that ELISA technique proved to be applicable for the rapid diagnosis of flacherie virus disease.

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Critical Temperature for Early Marginal Transplanting of Japonica Rice in Korea (우리나라 자포니카 벼 품종의 조기이앙 한계온도 분석)

  • Woonho Yang;Shingu Kang;Dae-Woo Lee;Mi-Jin Chae
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.68 no.4
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    • pp.246-261
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    • 2023
  • We investigated critical temperature for early marginal transplanting (CT-EMT) of the contemporary japonica rice varieties in Korea through the field, pot seedling tray, and the phytotron experiments during 2020 to 2023. The lowest mean temperature for 10 days from transplanting (MT-10DFT) that resulted in earlier heading date was 12.4℃ and the highest MT-10DFT that did not show the earlier heading date was 12.0℃ in the field study when the MT-10DFT varied by changing transplanting date. The lowest MT-10DFT that induced the increased biomass but not the earlier heading date was 11.6℃ and the highest MT-10DFT that showed neither the increased biomass nor the earlier heading date was 11.4℃. Compared to the 10-day later transplanting, the dates of the first root development, initiation of the chlorophyll recovery, and the first tiller development were earlier when the MT-10DFT was 9.1℃ or higher, 10.5℃ or higher, and 11.6℃ or higher, respectively, in the pot seedling tray and field experiments. The earliness of the first tiller development was a practical index for the estimation of CT-EMT during the early growth stage of rice. The response of transplanted rice to temperature treatments with the diurnal change of 10℃ in the phytotron study was similar to that shown in the field study. The data shown for constant temperature without a diurnal change revealed that the extent of positive effects of high temperature at day-time was greater than the extent of negative effects of low temperature at night-time on the early growth of transplanted rice. It was concluded that the critical MT-10DFT for early marginal transplanting of japonica rice in the temperate environments was between 11.4 to 11.6℃ based on the plant growth and between 12.0 to 12.4℃ based on the plant development.

Strength Development and Hardening Mechanism of Alkali Activated Fly Ash Mortar (알카리 활성화에 의한 플라이애쉬 모르타르의 강도 발현 및 경화 메커니즘)

  • Jo, Byung-Wan;Park, Min-Seok;Park, Seung-Kook
    • Journal of the Korea Concrete Institute
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    • v.18 no.4 s.94
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    • pp.449-458
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    • 2006
  • The discharge of fly ash that is produced by coal-fired electric power plants is rapidly increasing in Korea. The utilization of fly ash in the raw materials would contribute to the elimination of an environmental problem and to the development of new high-performance materials. So it is needed to study the binder obtained by chemically activation of pozzolanic materials by means of a substitute for the cement. Fly ash consists of a glass phase. As it is produced from high temperature, it is a chemically stable material. Fly ash mostly consists of $SiO_2\;and\;Al_2O_3$, and it assumes the form of an oxide in the inside of fly ash. Because this reaction has not broken out by itself, it is need to supply it with additional $OH^-$ through alkali activators. Alkali activators were used for supplying it with additional $OH^-$. This paper concentrated on the strength development according to the kind of chemical activators, the curing temperature, the heat curing time. Also, according to scanning electron microscopy and X-Ray diffraction, the main reaction product in the alkali activated fly ash mortar is Zeolite of $Na_6-(AlO_2)_6-(SiO_2)_{10}-12H_2O$ type.

Experimental study on ultra-high strength concrete(130 MPa) (초고강도 콘크리트(130MPa)에 대한 실험적 연구)

  • Cho Choonhwan;Yang Dong-il
    • Journal of the Korea Institute of Construction Safety
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    • v.6 no.1
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    • pp.12-18
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    • 2024
  • High-rise, large-scale, and diversification of buildings are possible, and the reduction of concrete cross-sections reduces the weight of the structure, thereby increasing or decreasing the height of the floor, securing a large number of floors at the same height, securing a large effective space, and reducing the amount of materials, rebar, and concrete used for designating the foundation floor. In terms of site construction and quality, a low water binder ratio can reduce the occurrence of dry shrinkage and minimize bleeding on the concrete surface. It has the advantage of securing self-fulfilling properties by improving fluidity by using high-performance sensitizers, making it easier to construct the site, and shortening the mold removal period by expressing early strength of concrete. In particular, with the rapid development of concrete-related construction technology in recent years, the application of ultra-high-strength concrete with a design standard strength of 100 MPa or higher is expanding in high-rise buildings. However, although high-rise buildings with more than 120 stories have recently been ordered or scheduled in Korea, the research results of developing ultra-high-strength concrete with more than 130 MPa class considering field applicability and testing and evaluating the actual applicability in the field are insufficient. In this study, in order to confirm the applicability of ultra-high-strength concrete in the field, a preliminary experiment for the member of a reduced simulation was conducted to find the optimal mixing ratio studied through various indoor basic experiments. After that, 130 MPa-class ultra-high-strength concrete was produced in a ready-mixed concrete factory in a mock member similar to the life size, and the flow characteristics, strength characteristics, and hydration heat of concrete were experimentally studied through on-site pump pressing.

An Economic Mix Design Methodology for the Development of Concrete Strength at Low Temperature (저온에서의 콘크리트 강도 확보를 위한 경제적 배합 방안)

  • Kim, Sang-Chel;Kim, Yong-Jic;Kim, Young-Jin
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.4
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    • pp.95-103
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    • 2012
  • Precast concrete method is known to have advantages of minimizing works in the construction, controlling concrete quality easily and saving construction period due to only fabrication work in the construction field, but it needs to apply steam curing to accelerate early concrete strength. In the meanwhile, the oil cost for steam curing has been continuously increased because of political instability in the middle East and international economic shaky. Thus, this study addresses the development of precast/ prestressed concrete which has over 14MPa at 1 day age and specified concrete strength of 40MPa at low temperature, not applying steam curing. Tests were carried out in terms of material characteristics in fresh concrete and compressive strength using 3 types of cement such as Type I, Type III and rapid hardening compound cement. As results of tests, it is found that cements for rapid hardening had disadvantages with respect to slump, slump loss, and air content, but showed higher compressive strength than specified one, especially the highest value when using rapid hardening compound.

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