• 제목/요약/키워드: downward

검색결과 1,530건 처리시간 0.027초

고분자 물질 첨가에 의한 2상 유동의 마찰 항력 감소와 대류 열전달 특성 (The Drag Reduction and Convective Heat Transfer Characteristics of Two-Phase Flow with Polymer Additives)

  • 이동상;김재근;차경옥
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 춘계학술대회논문집B
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    • pp.71-76
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    • 2000
  • This experimental study was conducted to figure out the drag reduction and convective heat transfer in vertical downward two-phase flow with polymer additives. The drag reduction effect were analyzed by using the difference of the pressure drop between the flow with polymer additives and without it. Experimental results show that the pressure drop with polymer additives is less than the pressure drop without polymer in vertical downward two-phase flow. And the convective heat transfer has decreased with increasing the polymer concentration in vertical downward two-phase flow.

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상향으로 설치된 쏘일네일링의 안정성 및 거동에 관한 연구 (A Study on the Stability and Behavior of upward Soil-nailing)

  • 김재윤;이인;최근혁;김홍택
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2009년도 춘계 학술발표회
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    • pp.1086-1091
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    • 2009
  • The purpose of this study is to provide the technical information of the stability change and behaviour characteristics in case upward direction of soil nailing is installed. Generally, the soil nailing which installed in case of vertical excavation or for the purpose of the slope stability is installed between 5 to 15 degree of downward direction. The downward direction of the soil nailing method has lots of advantages such as the increase of the stability, the convenience of the grout compared to upward direction of soil nailing. Even though the upward direction of the soil nailing has the disadvantages in terms of the stability and the grout construction, horizontal displacement tends to be decreased.

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Downward and Upward Air Flow Effects on Fume Particle Dispersion in Laser Line Cutting of Optical Plastic Films

  • Kim, Kyoungjin
    • 반도체디스플레이기술학회지
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    • 제19권2호
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    • pp.37-44
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    • 2020
  • In improving laser cutting of optical plastic films for mass production of optoelectronics display units, it is important to understand particle contamination over optical film surface due to fume particle generation and dispersion. This numerical study investigates the effects of downward and upward air flow motions on fume particle dispersion around laser cut line. The simulations employ random particle sampling of up to one million fume particles by probabilistic distributions of particle size, ejection velocity and angle, and fume particle dispersion and surface landing are predicted using Basset-Boussinesq-Oseen model of low Reynolds number flows. The numerical results show that downward air flow scatters fume particles of a certain size range farther away from laser cut line and aggravate surface contamination. However, upward air flow pushes fume particles of this size range back toward laser cut line or sucks them up with rising air motion, thus significantly alleviating surface contamination.

디지털 멀티미디어 방송을 위한 대화형 컨텐츠에 대한 Upward/Downward 최적화 기법 (Upward/Downward Optimization Technique for Interactive Digital Multimedia Broadcasting Contents)

  • 이송록;김상욱
    • 한국정보과학회:학술대회논문집
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    • 한국정보과학회 2006년도 한국컴퓨터종합학술대회 논문집 Vol.33 No.1 (B)
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    • pp.31-33
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    • 2006
  • 지상파 DMB 서비스에 사용되는 MPEG-4는 다양한 멀티미디어 객체와 객체간의 시공간 관계로 구성되어 있어 대화형 컨텐츠 저작에 용이하며 국내 지상파 DMB 표준 역시 이진 형태로 전승할 수 있는 MPEG-4 BIFS룰 채택하였다. 그러나 MPEG-4의 고유 특성으로 인하여 사용자 단말에서 DMB 컨텐츠를 재생하려면 컨텐츠를 구성하고 있는 미디어 객체들을 디코딩하기 전에 먼저 컨텐츠를 구성하고 있는 BIFS 정보부터 다운로드하고 디코딩하여야 한다. 그리하여 MPEG-4의 늪은 압축율에도 불구하고 제한된 대역폭과 저전송율에서 장면구성정보 등 부가데이터의 전송 및 디코딩으로 인한 지연이 발생되며, 따라서 컨텐츠 재생시간도 지연될 수 있다. 이와 같은 문제점들을 해결하기 위하여 모바일 DMB 단말에서 효율적인 대화형 MPEG-4 컨텐츠 저작 및 최적화 방안이 필요하다. 본 논문에서는 기존의 단순한 스트리밍 서비스와는 차별화된 인터랙티브한 양방향 서비스를 제공하기 위해서 풍부한 사용자 상호작용을 지원하는 대화형 MPEG-4 컨텐츠의 개발에서의 Upward/Downward 최적화 모듈을 설계하고 구현한다.

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Why Social Comparison on Instagram Matters: Its impact on Depression

  • Hwnag, Ha Sung
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제13권3호
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    • pp.1626-1638
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    • 2019
  • Social Networking Sites (SNS) provide people with unique online social interaction environments where users can disclose their thoughts, feelings, and opinions to their personal contacts. Although previous studies have suggested that such activities produce positive effects on SNS user well-being, this study considered potential negative effects by investigating the relationship between SNS use and depression. In particular, This stydy examined how specific activities are related to different types of social comparison (upward/downward/horizontal) and how these different types of social comparison influence depressed moods among college students. The analysis of a survey of 245 Instagram users found that (1) looking at other people's status updates and commenting on other people's photos influences upward social comparison, (2) frequency of Instagram use predicts upward/downward/horizontal social comparison, and (3) upward social comparison was postively associated with depression, while downward social comparison was negatively associated with depression. Furthermore, the path anlaysis show that social comparison mediates the effect of Instagram use on depression. It suggests that Instagram use does not directly increase depression but it can lead to depression when social comparison on Instagram triggers depression.

Counting Up while Doing Tasks Makes You Feel More Difficult than Counting Down

  • Ahn, Hee-Kyung
    • Asia Marketing Journal
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    • 제17권2호
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    • pp.63-71
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    • 2015
  • In this research, we explore whether mere exposure to external cues with vertical progress (e.g., moving upward or moving downward) can influence individuals' persistence to complete focal tasks. Drawing on the theory of embodied cognition, we propose that, a moving-upward (vs. downward) cue activates the abstract concept of difficulty, which is associated with the physical experience of climbing uphill (vs. downhill). Due to this association between moving uphill and difficulty, merely exposing individuals to the moving-upward cue can induce greater feeling of difficulty and this greater difficulty, in turn, reduce individuals' persistence, compared to exposing individuals to the moving-downward cue. Across three studies, we find supporting evidence for the effect of the external cues with vertical progress on individuals' performance both in physical tasks and in a cognitive task.

일반간호사의 조직 내 의사소통 유형과 직무만족 및 간호업무성과의 관계 (Relations Between the Types of Communication and, Job Satisfaction and Nursing Performance in Staff Nurses)

  • 서이아;박경민;이병숙
    • 한국보건간호학회지
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    • 제17권2호
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    • pp.317-332
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    • 2003
  • This study attempts to investigate the relations between the types of communication, the job satisfaction. and the nursing performance of the staff nurses. The subjects of this study were the 114 nurses working in general wards, intensive care units, and the emergency rooms of the general hospital in Kyongbuk province. They were asked to answer the questionnaires as regards the types of communication and job satisfaction, and their performance of nursing, and these were evaluated by the head nurses, and their direct seniors. The data were collected for 10 days from the September 17 to 26, 2002. According to the purpose of the study, descriptive analysis, ANOVA. Pearson correlation coefficient, and stepwise multiple regression were applied for the data analysis using SPSS 10.0. The results are as follows : 1. The types of communication of staff nurses showed that the upward communication was $3.12\pm0.56$. the downward communication was $3.56\pm0.42$. the horizontal communication was $2.98\pm0.44$. and the informal communication was $2.59\pm0.49$. It showed that the most frequent communication was the downward communication. 2. In terms of the job satisfaction, there was significant difference according to the length of the period working for one ward (F=5.95, p=0.003), 3. The performance of nursing was significantly different according to the age (F=23.52, p=0.000), the working duration as a nurses (F=21.9, p=0.000), the types of nursing unit (F=5.33, p=0.002), and the working duration in present nursing unit (F=15.87, p=0.000). 4. In terms of communication type, the job satisfaction was associated with quality of the upward communication (F=6.23, p=0.003), the downward communication (F=5.78, p=0.004), and the horizontal communication (F=11.73, p=0.000) There were no association between the types of communication and the performance of nursing. 5. There was a positive correlation between the communication and the job satisfaction. And the downward communication (r=0.398) showed the greatest correlation with the job satisfaction. There was no statistically significant correlation between the communication and the performance of nursing. And the upward communication (r=-0.058) showed a negative, though not significant correlation with performance of nursing. 5. There was a positive correlation between the communication and the job satisfaction. And the downward communication (r=0.398) showed the greatest correlation with the job satisfaction. There was no statistically significant correlation between the communication and the performance of nursing. And the upward communication (r=-0.058) showed a negative. though not significant correlation with performance of nursing. 6. The stepwise multiple regression result showed that the downward communication accounts for $15.8\%$ (p=0,000) of the job satisfaction.

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소비자 지각측면의 브랜드 가치가 수직적 브랜드확장의 확장방향성 형태별 제품 수용도에 미치는 영향 (The Effects of Consumers' Perceptual Brand Value on the Receptive Degree of Product in Extension Types of Vertical Brand Extension)

  • 김화동
    • 디지털융복합연구
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    • 제12권11호
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    • pp.57-69
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    • 2014
  • 본 연구는 실제 브랜드를 이용하여 소비자 지각측면에서 인식되고 있는 브랜드 가치의 구성요소들이 수직적 브랜드확장의 제품 수용도에 미치는 영향과 그에 따른 확장 방향성 형태별 제품 수용도의 차이를 규명하였다. 첫째, 브랜드 인지도는 상향적 확장과 하향적 확장 모두에서 긍정적인 영향을 주며, 제품 수용도가 상향적 확장보다는 하향적 확장에서 더 큰 것으로 확인되었다. 둘째, 브랜드 연상은 상향적 확장에서는 긍정적인 영향이 주지 못한 반면에 하향적 확장에서는 긍정적인 영향을 주고 있는 것으로 확인되었다. 셋째, 지각된 품질은 브랜드 인지도와 같은 결과를 보이고 있는 가운데 지각된 품질이 높은 경우에서 상향적 확장의 제품 수용도가 브랜드 인지도가 높은 경우와 브랜드 연상이 높은 경우와 비교해 더 높은 것으로 확인되었다. 넷째, 브랜드 가치 구성요소들의 상호작용에 따른 영향을 분석한 결과, 브랜드 인지도 및 브랜드 연상은 하향적 확장에서만, 브랜드 인지도 및 지각된 품질과 브랜드 연상 및 지각된 품질은 상향적 확장과 하향적 확장 모두에서 상호작용효과로 인해 제품 수용도의 차이가 더 큰 것으로 확인되었다.

AERODYNAMIC EFFECT OF ROOF-FAIRING SYSTEM ON A HEAVY-DUTY TRUCK

  • KIM C. H.;YOUN C. B.
    • International Journal of Automotive Technology
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    • 제6권3호
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    • pp.221-227
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    • 2005
  • Aim of this study is to investigate an aerodynamic effect of a drag-reducing device on a heavy-duty truck. The vehicle experiences two different kinds of aerodynamic forces such as drag and uplifting force (or downward force) as it is traveling straight forward at constant speed. The drag force on a vehicle may cause an increase of the rate of fuel consumption and driving instability. The rolling resistance of the vehicle may be increased as result of the negative uplifting or downward force on the vehicle. A device named roof-fairing system has been applied to examine the reduction of aerodynamic drag force on a heavy-duty truck. As for a engineering design information, the drag-reducing system should be studied theoretically and experimentally for the best efficiency of the device. Four different types of roof-fairing model were considered in this study to investigate the aerodynamic effect on a model truck. The drag and downward force generated by vehicle has been obtained from numerical calculation conducted in this study. The forces produced on four fairing models considered in this study has been compared each other to evaluate the best fairing model in terms of aerodynamic performance. The result shows that the roof-fairing mounted truck has bigger negative uplifting or downward force than that of non-mounted truck in all speed ranges, and drag force on roof-fairing mounted truck has smaller than that of non-mounted truck. The drag coefficient $(C_D)$ of the roof-fairing mounted truck (Model-3) is reduced up to $41.3\%$ than that of non-mounted trucks (Model-1). A downward force generated by a roof-fairing mounted on a truck is linearly proportional to the rolling resistance force. Therefore, the negative lifting force on a heavy-duty truck is another important factor in aerodynamic design parameter and should be considered in the design of a drag-reducing device of a tractor-trailer. According to the numerical result obtained from present study, the drag force produced by the model-3 has the smallest of all in all speed ranges and has reasonable downward force. The smaller drag force on model-3 with 2/3h in height may results of smallest thickness of boundary layer generated on the topside of the container and the lowest intensity of turbulent kinetic energy occurs at the rear side of the container.

몸과 소통에 관한 연구 (Study of Mutual Understanding and Human Body)

  • 조원준;김영목
    • 동의생리병리학회지
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    • 제21권4호
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    • pp.822-834
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    • 2007
  • This study searched the philosophical and medical thought of mutual understanding and human body. Mutual understanding is a fundamental problem in all branches of oriental studies. In other words, mutual understanding becomes the existential foundation of heaven-earth-human(三才). So human beings, heaven and the earth can't exist if there is no mutual understanding. It comes out the problem of self-consciousness in philosophy, and qi movement pattern like upward, downward, inward and outward movement in traditional korean medicine. Human beings have mutual understandings with heaven and the earth from a macroscopic standpoint, on the other side the human body from a microscopic standpoint. Qi movement is the mutual understanding and response of qi in human body, so with which the physiological functions and pathologic changes of viscera and bowels comes out. Therefore we want to present how to complete qi movement between viscera-bowels and organs to examine mutual understandings in human body closely. The results was summarized as follows; First, upbearing the clear yang and down bearing the turbid yin of spleen-stomach is main pivot of upward and downward of qi movement, and it is true form of mutual understandings between viscera and bowels, so upward, downward, inward and outward movement of whole viscera and bowels can be controlled by spleen-stomach. Second, by restraining relationships between downward heart fire and upward kidney water, heart fire and kidney water have close communications physiologically and pathologically as upper-lower, yin-yang and water-fire. Third, by restraining relationships between upbearing and effusion of liver and purification and down-sending of lung, liver and lung are outer circles of upward and downward movement, so they have antagonistic functions. Firth, by the relationships between upbearing the clear and down bearing the turbid of spleen-stomach and free coursing of liver, free coursing of liver-gallbladder is the essential requirement that it certify transportation and transformation of spleen-earth, so the disease of liver-gallbladder induce spleen-stomach disease pattern to affect its function of transportation and transformation. Fifth, by spleen and kidney, spleen yang is based on kidney yang, so the weakness of kidney yang can affect the function of transportation and transformation of spleen-stomach as it can't warm spleen earth. Sixth, by homogeny of liver-kidney, essence and blood of liver-kidney and ministerial fire of liver-kidney have mutal generation and limitation physiologically and they mutually are affected in pathologically.