• 제목/요약/키워드: Stratification effect

검색결과 269건 처리시간 0.034초

FCST 원리를 적용한 TBA-G의 골프 드라이버 헤드 속도와 배근력 영향에 대한 연구 (A Study on the Effect of Golf Driver Head Speed and Back Muscular Strength in TBA-G of FCST)

  • 선승호;박창운;정혜정;안성훈;손인철;이영준
    • 대한한의학회지
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    • 제34권1호
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    • pp.80-88
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    • 2013
  • Objectives: The purpose of this study was to examine the effect of Temporomandibular joint Balance Appliance for Golf (TBA-G) of Functional Cerebrospinal Therapy (FCST) on golf driver head speed and back muscle power. Methods: Twenty-one participants that had a golf career of 4 years or more were involved. We measured golf drive head speed and back muscular strength before and after applying TBA-G in the mouth. A paired t test or Wilcoxon singed rank test was performed to identify the difference of effect between before and after applying TBA-G, using IBM SPSS 19.0. We considered difference significant at P<0.05. Results: Driver head speed increased significantly by 2 mph (1.99%) after applying TBA-G [from $100.52{\pm}9.82$ mph ($mean{\pm}SD$) to $102.52{\pm}10.43$ mph, P<0.001]. Back muscular strength also increased by 7.28 kg (5.60%) [from $129.90{\pm}28.31$ kg to $137.18{\pm}28.81$ kg, P<0.001]. In stratification analysis, a more significant increase was found in the drive head speed and back muscular strength of groups of males with weight more than 69kg, with height more than 175cm, and with golf experience more than 7 years, compared to those of other groups. Conclusions: The results suggest that TBA-G could improve golf drive head speed and back muscular strength.

Overview of separate effect and integral system tests on the passive containment cooling system of SMART100

  • Jin-Hwa Yang;Tae-Hwan Ahn;Hong Hyun Son;Jin Su Kwon;Hwang Bae;Hyun-Sik Park;Kyoung-Ho Kang
    • Nuclear Engineering and Technology
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    • 제56권3호
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    • pp.1066-1080
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    • 2024
  • SMART100 has a containment pressure and radioactivity suppression system (CPRSS) for passive containment cooling system (PCCS). This prevents overheating and over-pressurization of a containment through direct contact condensation in an in-containment refueling water storage tank (IRWST) and wall condensation in a CPRSS heat exchanger (CHX) in an emergency cool-down tank (ECT). The Korea Atomic Energy Research Institute (KAERI) constructed scaled-down test facilities, SISTA1 and SISTA2, for the thermal-hydraulic validation of the SMART100 CPRSS. Three separate effect tests were performed using SISTA1 to confirm the heat removal characteristics of SMART100 CPRSS. When the low mass flux steam with or without non-condensable gas is released into an IRWST, the conditions for mitigation of the chugging phenomenon were identified, and the physical variables were quantified by the 3D reconstruction method. The local behavior of the non-condensable gas was measured after condensation inside heat exchanger using a traverse system. Stratification of non-condensable gas occurred in large tank of the natural circulation loop. SISTA2 was used to simulate a small break loss-of-coolant accident (SBLCOA) transient. Since the test apparatus was a metal tank, compensations of initial heat transfer to the material and effect of heat loss during long-term operation were important for simulating cooling performance of SMART100 CPRSS. The pressure of SMART100 CPRSS was maintained below the design limit for 3 days even under sufficiently conservative conditions of an SBLOCA transient.

CNG 직접분사식 연소기에서의 열량해석(2) : 비균질급기 (Analysis of Heat Quantity in CNG Direct Injection Bomb(2) : Inhomogeneous Charge)

  • 최승환;전충환;장영준
    • 한국자동차공학회논문집
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    • 제12권2호
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    • pp.24-31
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    • 2004
  • A cylindrical constant volume combustion bomb is used to investigate the combustion characteristics and to analyzer the heat quantity of inhomogeneous charge methane-air mixture. To analyze the heat quantity, some definitions including the CHR ratio, the UHC ratio and the HL ratio are needed and are calculated. It is shown that the effect of stratification is not significant in case of the overall excess air ratio of 1.1, mainly due to the higher heat loss and lower thermal efficiency compared to those of homogeneous condition. In the case of the overall excess air ratio of 1.4, as the initial charge pressure decreases, the CHR ratio has been decreased while the HL ratio has been increased, Generally, as the initial charge pressure increases, the amount of injection mixture has been decreased and has resulted in lower mean velocity and turbulence intensity for injection mixture. Also, the injected mixture is too rich to result in mixing deficiency in combustion chamber. From these results, it could be possible to acquire the improvement of thermal efficiency and the reduction of heat loss simultaneously through the 2-stage injection in CNG direct injection engine.

개갑 인삼종자의 발아 적정 저온감응기간 (Optimum Chilling Terms for Germination of the Dehisced Ginseng(Panax ginseng C. A. Meyer) Seed)

  • 권우생;이장호;이명구
    • Journal of Ginseng Research
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    • 제25권4호
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    • pp.167-170
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    • 2001
  • 개갑 인삼종자의 생리적 휴면타파를 위한 적정 저온감응기간을 조사하였다. 채종하여 3개월간 모래로 층적저장하여 개갑이 완료된 종자의 배는 배유의 1/2정도의 크기를 보였다. 인삼종자는 채종 당시의 미숙한 배가 형태적으로 거의 완전한 발달을 보이기까지는 6개월 정도가 소요되었으며, 배의 신장의 실외보다는 실내에 저장하였던 종자가 더 빨리 자랐다. 배 신장이 완료된 종자라 할지라도 60일 이하의 저온처리된 종자는 발아가 되지 않았으며, 발아에 필요한 저온감응기간은 실외의 자연상태에서는 75일 정도이며, 냉장온도(4$^{\circ}C$)에서는 90일 정도가 적정하였다. 그러나 적정의 저온감응을 받은 종자라 할지라도 상온데 지속적으로 방치하게 되면 그 효과는 현저히 감소되었다.

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난류가 플랑크톤의 거동에 미치는 영향: 역학적 관점에서 본 얇은 층의 형성과정 (Effect of Turbulence on the Plankton Behavior: Mechanical Perspective of a Process for Developing Thin Layers)

  • 황진환
    • 한국해양학회지:바다
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    • 제17권4호
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    • pp.283-291
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    • 2012
  • 본 연구에서는 최근 물리적 관측 방법으로 그 존재가 확인된 얇은 층(thin layer)의 형성 메커니즘에 대하여 검토하였다. 기존의 연구들에서는 성층과 전단응력의 상대적 크기인 Richardson수가 얇은 층의 중요한 결정요인인 것으로 밝혀졌다. 성층이 없는 조건하에서의 물리적 수치 실험은 미세 난류(micro-structure turbulence)가 플랑크톤의 거동에 변화를 주어 성장과 재생산 등에 영향줄 수 있음을 설명하였다. 기존의 플랑크톤 거동에 성층과 전단응력의 효과를 고려하여 최근 Gyrotaxis의 메커니즘으로 얇은 층이 형성되는 과정을 설명하였다. 이러한 생태학적 문제에 물리학적 연구방법론의 적용이라는 최근의 연구경향은 현재 및 향후에 해양생태학에서 중요한 접근방법이라고 할 수 있다.

RCCI/SCCI 조건하에서 희박 PRF/공기 혼합물의 점화에 관한 직접수치모사를 이용한 비교 연구 (DNSs of the Ignition of a Lean PRF/Air Mixture under RCCI/SCCI Conditions: A Comparative Study)

  • ;유광현;유춘상
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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    • pp.179-182
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    • 2014
  • A comparative DNS study of the ignition characteristics of dual-fueled reactivity controlled compression ignition (RCCI) and stratification charge compression ignition (SCCI) is investigated using a 116-species reduced primary reference fuel (PRF) mechanism. In the RCCI combustion, two PRF fuels (n-heptane and iso-octane) with opposite autoignition characteristics are separatedly supplied and in-cylinder blended such that spatial variations in fuel reactivity, fuel concentration and temperature are achieved. In the SCCI combustion, however, just a single fuel (PRF50) is used such that only fuel concentration and temperature inhomoginieties are obtained. Because three factors, rather than only two as in SCCI combustion, govern the overall RCCI combustion, combustion timing and combustion duration or heat release rate of RCCI combustion are flexibly and effectively controlled. It is found that the overall RCCI combustion occurs much earlier and its combustion duration is longer compared to SCC combustionI. Moreover, the negative temperature coefficient (NTC) has a positive effect on enhancing RCCI combustion by inducing a shorter combustion timing and a longer combustion duration as a result of the occurrence of a predominant low-speed deflagration-combustion mode.

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직분식 가솔린 인젝터의 분사 조건에 따른 분무 특성 분석 (An Investigation of the Spray Characteristics according to Injection Conditions for a Gasoline Direct Injector)

  • 이기형;이창식;이창희;류재덕;배재일
    • 한국자동차공학회논문집
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    • 제9권5호
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    • pp.89-95
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    • 2001
  • Recently GDI(Gasoline Direct Injection) engine is spotlighted to achieve higher thermal efficiency under partial loads and better performance at full loads. To realize this system, it is essential to make both stratified combustion and homogeneous combustion. When compared to PFI(Port Fuel Injection) engine, GDI engine needs more complicated control and optimal design with injection system. In addition, spray pattern must be optimized according to injection timing because ambient pressure in combustion chamber is also varied. Thus spray structure should be analyzed in details to meet various conditions. In this experimental study, two types of visualization system were developed to simulate compression stroke and intake stroke, respectively. With an increase of the ambient pressure, the penetration length tends to decrease due to rising resistance caused by the drag force of the ambient air. Spray characteristics impinged on the piston has a significant effect on mixture stratification around the spark plug. These results provide the information on macroscopic spray structure and design factors far developing GDI injector.

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국민건강영양조사 자료의 복합표본설계효과와 통계적 추론 (Complex sample design effects and inference for Korea National Health and Nutrition Examination Survey data)

  • 정진은
    • Journal of Nutrition and Health
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    • 제45권6호
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    • pp.600-612
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    • 2012
  • Nutritional researchers world-wide are using large-scale sample survey methods to study nutritional health epidemiology and services utilization in general, non-clinical populations. This article provides a review of important statistical methods and software that apply to descriptive and multivariate analysis of data collected in sample surveys, such as national health and nutrition examination survey. A comparative data analysis of the Korea National Health and Nutrition Examination Survey (KNHANES) was used to illustrate analytical procedures and design effects for survey estimates of population statistics, model parameters, and test statistics. This article focused on the following points, method of approach to analyze of the sample survey data, right software tools available to perform these analyses, and correct survey analysis methods important to interpretation of survey data. It addresses the question of approaches to analysis of complex sample survey data. The latest developments in software tools for analysis of complex sample survey data are covered, and empirical examples are presented that illustrate the impact of survey sample design effects on the parameter estimates, test statistics, and significance probabilities (p values) for univariate and multivariate analyses.

포트 마스킹에 따른 엔진 부분부하 성능 특성 (Part Load Performance Characteristics according to Port Masking)

  • 김형식;김인옥;박찬준;엄인용
    • 한국자동차공학회논문집
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    • 제19권2호
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    • pp.42-49
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    • 2011
  • To expand lean misfire limit and improve combustion stability, the effects of port masking were estimated to secure basic data for applying the mechanism to SI engine instead of asymmetrical port and port throttling devises. For this purpose, various shapes and ratios of masking plates were mounted between port and manifold. The masking effects were evaluated by mixture response test under various load and speed conditions. The results showed that lean misfire limits were expended and fast combustion was observed for all masking shapes and ratios, especially, the effect of diagonal 1/4 masking was remarkable. In conclusion, the port masking method could be easily applied to engine without redesign of port for improving part load performance.

Roles of Galectin-7 in Cancer

  • Kaur, Manpreet;Kaur, Tarnjeet;Kamboj, Sukhdev Singh;Singh, Jatinder
    • Asian Pacific Journal of Cancer Prevention
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    • 제17권2호
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    • pp.455-461
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    • 2016
  • Galectins are ${\beta}$-galactoside binding lectins that contain one or more carbohydrate recognition domains. As a consequence of sugar-binding properties, galectins exhibit a variety of interactions with glycoproteins, thus playing important roles in various pathological processes. A number of studies have shown roles of galectins in cancer. Galectin-7 is a prototype member of the galectin family implicated in epithelial stratification and cell migration. It can act as a potent dual regulator in different types of cancer. Galectin-7 may contribute either to neoplastic transformation and tumour progression through regulation of cell growth, cell cycle, angiogenesis, apoptosis and cell migration or may have a protective effect in cancer depending on the tissue type. A perusal of the literature indicates particular roles of galectin-7 in carcinomas and melanomas, while contributions await greater exploration in other types of cancers including sarcomas and leukemia. This review collectively summarizes available literature on expression and roles of galectin-7 in different cancers.