• Title/Summary/Keyword: case-controlled study

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A Study on the Combustion Characteristics of Swirling Jet Combustor (선회분류 연소기의 연소특성에 관한 연구)

  • 심순용;손강호;이창식
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.2
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    • pp.492-501
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    • 1994
  • This study is an analysis of the turbulent diffusion flame with swirl flow and the calculated results are compared with experimental data in case of various swirl numbers and air-fuel rations. The mathematical model is restricted to single-phase, diffusion controlled combustion with swirl flow. Values of local flow properties were obtained by solving appropriate differential equation for continuity, momentum, stagnation enthalpy, concentration, turbulence energy, dissipation rate of turbulence energy, and the mean square of concentration fluctuation. The method is proposed for calculating the local probability of chemical reaction based on the use of the probability density function for the mixture fraction.

The study of Safety education, safe experience for students to develop research simulreyiteo (안전체험 시뮬레이터 개발에 관한 연구)

  • Kim, Tae-hwan
    • Journal of the Society of Disaster Information
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    • v.6 no.1
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    • pp.46-59
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    • 2010
  • In this study, the safety training of comparative analysis of the realities of Korea's safety training and international experience and practical training for the safety experience of a virtual reality simulator, the development of safe conduct as a controlled motion simulator system, image H / W and the control system works, sound effects H / W and the control system works, 4D special effects (smoke, heat, wind, vibration) and a control system integration, mission control system for the selection and evaluation of the proposal, and safety training on Game S / W of development as we have never experienced an earthquake action plan and evacuate to escape the power of experience and the experience of an earthquake (vibration + video), Also the collapse and a fire escape on the experience of following second disaster, the building collapsed during an escape experience in the field, in case of fire According to the initial fire suppression and fire extinguisher usage experience - experience of smoke and heat to escape in, Moreover, the Daegu subway fire in public places such as subway and evacuated to escape the experience, considering the suggested Simulator.

The study on the anti-allergic effect of SoPungSan-Gami (消風散加味의 抗알레르기 效果에 關한 實驗的 硏究)

  • Lee, Jun-Seong;Seo, Hyung-Sik;Roh, Seok-Seon
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.14 no.2
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    • pp.9-20
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    • 2001
  • This study was carried out to prove the anti-allergic effect of SPS-GM, which is gained by controlled Cytokines making all the difference to Th2 cell development. The results were obtained as follows : 1. From the SPS-GM treatment about BMC cell, in case of the IL-4, an important factor of the Th2 cell development, SPS-GM didn't show considerable effect. 2. The INF-${\gammer}$, mutual Cytokines of IL-4, was increased more than twice. 3. Histamine from the Master cell and Nitric oxide from indisposition response were a little decreased. According to the above results, it is suggested that SPS-GM has anti-allergic effect.

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Enhancement of Surface Diffusivity for Waviness Evolution on Heteroepitaxial Thin Films

  • Kim, Yun Young
    • Journal of Surface Science and Engineering
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    • v.47 no.6
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    • pp.287-292
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    • 2014
  • The present study deals with a numerical analysis on the island growth of heteroepitaxial thin-films through local surface diffusivity enhancement. A non-linear governing equation for the surface waviness evolution in lattice-mismatched material systems is developed for the case of spatially-varying surface diffusivity. Results show that a flat film that is stable under constant diffusivity conditions evolves to form nanostructures upon externally-induced spatial diffusivity modulation. The periodicity of waviness can be controlled by changing the modulation parameters, which allows for generation of pattern arrays. The present study therefore points towards a post-deposition treatment technique that achieves controllability and order in the structure formation process for applications in nanoelectronics and thin-film devices.

An Experimental Study of the Micro Turbojet Engine Fuel Injection System

  • Choi, Hyun-Kyung;Choi, Seong-Man;Lee, Dong-Hun
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.03a
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    • pp.1-5
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    • 2008
  • An experimental study was performed to develop the rotational fuel injection system of the micro turbojet engine. In this system, fuel is sprayed by centrifugal forces of engine shaft. The test rig was designed and manufactured to get droplet information on combustion space. This experimental apparatus consist of a high speed rotational device(Air-Spindle), fuel feeder, rotational fuel injector and acrylic case. To understand spray characteristics, spray droplet size, velocity and distribution were measured by PDPA (Phase Doppler Particle Analyzer) and spray was visualized by using Nd-Yag laser-based flash photography. From the test results, the length of liquid column from injection orifice is controlled by the rotational speeds and Sauter Mean Diameter(SMD) is decreased with rotational speed. Also, Sauter Mean Diameter is increased as increasing mass flow rate at same rotational speeds.

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Interventions of Korean Medicine for Hip Pain: A Literature Review of Case Studies (고관절 통증에 대한 한의학적 치료: 증례연구의 문헌적 분석)

  • Park, Sang-Cheol;Sung, Soo-Hyun;An, Tteul-E-Bom;Shin, Byung-Cheul;Choi, Gwang-Ho;Park, Jong-Hyun
    • Journal of Korean Medicine Rehabilitation
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    • v.27 no.1
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    • pp.27-35
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    • 2017
  • Objectives This study aimed to review case studies on interventions of Korean medicine for hip pain. Methods We searched seven electronic databases for relevant studies up to Oct 2016. Case studies of Korean medicine interventions for hip pain were included and analysed. Results 15 case studies were included (Korean databases; n=15) and Total number of patients was 17 cases. A total of 13 types of interventions were reported, of which acupuncture (93.3%), herbal medicine (80.0%) and pharmacopuncture (40.0%) were the most frequently used. GB30 (66.7%), LR3 (41.7%), BL36 (33.3%) and ST31 (33.3%) were used in at least 4 papers. Cheongpa-jeon (25.0%) and symptom change (46.7%) were most frequently used in herbal medicine and outcome measure respectively. Conclusions Clinical studies, especially double-blinded randomized controlled trials, of Korean medicine interventions for hip pain must be conducted to obtain definite conclusions.

A Review of Research on the Effects of Acupuncture and Moxibustion Treatment to Complex Regional Pain Syndromes (복합부위통증증후군의 침구치료 효과에 대한 연구동향 고찰)

  • Kim, Ho Sun;Bae, Young Hyun;Kim, Hae Sol;Suh, Chang Yong;Kim, No Hyeon;Yang, Kyu Jin;Lee, Gi Bum
    • Journal of Acupuncture Research
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    • v.33 no.4
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    • pp.137-148
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    • 2016
  • Objectives : This study was performed to review articles concerning acupuncture or moxibustion treatment for Complex Regional Pain Syndromes. Methods : On-line databases including PubMed, Cochrane Library, Ovid-EMBASE, NDSL and OASIS were searched to find articles concerning acupuncture or moxibustion treatment for Complex Regional Pain Syndromes. Several overlapping articles and those not relevant to the topic were excluded, as well as review articles and commentaries. Results : 16 case reports were selected through the procedure, all of which presented successful treatment cases of Complex Regional Pain Syndromes with acupuncture and moxibustion. Most of them presented one single patient case and were published in Korea. However, almost half of them were printed in English, and had been continuously published since 2005. It was remarkable that pharmacopuncture was predominantly used to treat Complex Regional Pain Syndromes. Also, we noted that Chinese scalp acupuncture needs to be studied further as two successful cases were presented from the U.S army. Conclusion : The results show that several case reports have been published regarding Complex Regional Pain Syndromes treated with acupuncture and moxibustion. However, all of them were case reports which are given low status in Evidence-Based Medicine. We expect that a more diverse range of articles, including case control studies, cohort studies and randomized controlled trials will be performed in the near future, and that a unified outcome measure will be developed for Complex Regional Pain Syndromes.

Finite Element Analysis of Post-Buckling Phenomena Using Adaptive Load/ Displacement Parameter (선택적 하중/변위 파라미터를 이용한 좌굴후 현상의 유한요소 해석)

  • 최진민;정윤태;윤태혁;권영두
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.3
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    • pp.503-512
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    • 1990
  • In this study, a penalty method effective for the case that has no snap-back phenomenon, is proposed and an adaptive method which choose the penalty method or Riks' type method, is suggested for the case of snap-back problem. And for the case that loads are applied to one or more points of a structure, the Riks' method is applied in general, but under certain condition choice of new incremental load parameter is suggested to accelerate the convergence rate. Finally, for the case that displacements of a structure are controlled at one or more points Riks' type method is proposed. In this case, the proposed method is applied in general but under certain condition it is recommended to choose other incremental displacement parameter to eliminate probable divergence. Five examples are analysed and compared with the result of published literature.

Water Vapor Transmission for T800/AD6005 Based Composite Motor Case (T800/AD6005계 복합재 연소관의 습기 투과에 관한 연구)

  • 박명규;류백능;최영보;도영대
    • Journal of the Korean Society of Propulsion Engineers
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    • v.2 no.1
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    • pp.50-58
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    • 1998
  • Water vapor transmission was tested in water bath controlled by $20^{\cire}C$, 90%RH for T800/AD6005 based composite motor case which made by filament winding method. We detected internal relative humidity of composite motor case by inserting the humidity detector through the head of motor case for the study of humidity transmission through the wall of composite motor case. We found out that this composite material appears the water vapor flux of 2.88${\times}$$10^{-9}$g/$\textrm{m}^2$sec and diffusivity of 7.98${\times}$$10^{-7}$$\textrm{mm}^2$/sec at $20^{\cire}C$, 90%RH water vapor condition.

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Sinus floor elevation and simultaneous implant placement in fresh extraction sockets: a systematic review of clinical data

  • Ekhlasmandkermani, Mehdi;Amid, Reza;Kadkhodazadeh, Mahdi;Hajizadeh, Farhad;Abed, Pooria Fallah;Kheiri, Lida;Kheiri, Aida
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.47 no.6
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    • pp.411-426
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    • 2021
  • Combining different procedures to reduce the number of surgical sessions and patient discomfort in implant placement and sinus floor elevation has been recommended, and evidence supports good outcomes. The aim of this study was to review the results of clinical studies on sinus floor elevation through extraction sockets and simultaneous immediate posterior implant placement. An electronic search was carried out in PubMed, Scopus, and Web of Science to find English articles published in or before August 2020. A manual search was also performed. Titles, abstracts, and the full-text of the retrieved articles were studied. Thirteen studies met our eligibility criteria: 6 retrospective case series, 3 case reports, 2 prospective cohort case-series, 1 prospective case series, and 1 randomized controlled trial. Overall, 306 implants were placed; 2 studies reported implant survival rates of 91.7% and 98.57%. The others either did not report the survival rate or reported 100% survival. Sinus floor elevation through a fresh extraction socket and simultaneous immediate implant placement appears to be a predictable modality with a high success rate. However, proper case selection and the expertise of the clinician play fundamental roles in the success of such complex procedures.