• Title/Summary/Keyword: Flow state

검색결과 3,205건 처리시간 0.033초

Influence of Pore Pressure Behind a Subsea Tunnel on Its Stability (터널 배면의 간극수압이 해저터널의 안정성에 미치는 영향)

  • You, Kwang-Ho;Lee, Kwang-Hoon
    • Journal of Korean Tunnelling and Underground Space Association
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    • 제8권4호
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    • pp.355-363
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    • 2006
  • In this study, it was analyzed how the pore pressure behind a subsea tunnel influences on the stability of the tunnel. The tunnel is located in the soft rock layer, and a soft sandy layer and weathered soil layer are located on the top of it. Coupled numerical analyses are performed for both drained and undrained condition with varying coefficients of lateral earth pressure. In the case of undrained conditions, the stability of the tunnel was analyzed with different thicknesses of shotcrete. On the other hand, a sensitivity analysis was performed with different hydraulic conductivities and porosities of the shotcrete for the drained conditions. The stability of a subsea tunnel was evaluated in terms of safety factor suggested by You et al.(2000, 2001, 2005) based on the shear strength reduction technique. In this paper, the safety factor of a tunnel was calculated under steady state flow condition during hydro-mechanical coupled analysis. As a result, it was found that the stability of a subsea tunnel could be rather increased by allowing a proper amount of groundwater inflow into a subsea tunnel.

Effect of Tea Polyphenols on the Adhesion of Highly Metastatic Human Lung Carcinoma Cell Lines to Endothelial Cells in Vitro

  • Zheng, Feng-Jin;Shi, Lin;Yang, Jun;Deng, Xiao-Hui;Wu, Yu-Quan;Yan, Xi-Qing;Huang, Ning
    • Asian Pacific Journal of Cancer Prevention
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    • 제13권8호
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    • pp.3751-3755
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    • 2012
  • Aim: Tea polyphenols are known to play roles in critical steps of human lung carcinoma cell metastasis. For understanding the mechanisms whereby they inhibit tumor metastasis, the present study was conducted to investigate their effects on the adhesion of highly metastatic lung carcinoma cell lines (PG cells) to endothelial cells (EC cells) and adhesion molecule expression in vitro. Methods: The expression of CD44 or CD54 in the PG cells was detected by flow cytometry and adhesion of PG cells to EC cells was assessed by confocal microscopy double fluorescence staining. Results: The results showed that tea polyphenols: (1) inhibited the expression of CD44 and CD54, two important adhesion molecules in the PG cells in a dose-dependent manner; (2) significantly blocked the adhesion of PG cells to EC cells not only in a state of rest but also when active; and (3) influenced CD44 and CD54 expression during the adhesion process of PG cells to EC cells. Conclusions: The data indicated that the blocking role of tea polyphenols in the adhesion of PG cells to EC cells is related to CD44 and CD54. The mechanism of tea polyphenol prevention of human lung carcinoma metastasis might be through inhibiting adhesion molecule expression to block cancer cell adhesion.

A Study on the Performance of the Heat Transfer for the Liquid Filling as the Ratio of Working Fluid Volume to Total Volume of the Thermosyphon with Axial Internal Fins (축방향 내부 핀을 가진 열사이폰의 작동유체 체적변화에 대한 열전달 성능에 관한 연구)

  • Lee, Jung-Han;Lee, Ki-Baik;Cho, Dong-Hyun
    • Journal of the Korean Solar Energy Society
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    • 제22권1호
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    • pp.23-30
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    • 2002
  • This study concerns the performance of the heat transfer of the thermosyphon having 80 internal fins in which boiling and condensation occur. Water has been used as the working fluid. The Liquid filling as the ratio of working fluid volume to total volume of thermosyphon have been used as the experimental parameters. The heat flux and heat transfer coefficient at the condenser are estimated from the experimental results. The experimental results have been assessed and compared with existing theories. As a result of the experimental investigation we can state that the maximum heat flow rate in the thermosyphon prove to depend upon the liquid fill quantity. The relatively high rates of heat transfer have been achived operating in the thermosyphon with axial internal fins. Also, the thermosyphon with internal micro fins can be used to achieve some inexpensive and compact heat exchangers in low temperature. In addition, it is to obtain the overall heat transfer coefficients and the characteristics as a operating temperature for the practical applications.

A Literature study about comparison of Eastern-Western medicine on the Tinnitus (이명(耳鳴)의 동(東)·서의학적(西醫學的) 문헌(文獻) 고찰(考察))

  • Heo, Eun-Sun;Hwang, Chung-Yeon
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • 제29권4호
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    • pp.114-130
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    • 2016
  • Objectives : This study is performed to investigate the therapy on tinnitus through the literature of Eastern and Western medicine. Methods : This study review the definition, etiology, classification, internal and external methods of treatment of tinnitus based on 50 articles of Eastern medicine, 16 articles of Western medicine about the treatment of tinnitus. Results : The results were as follows. 1. In Eastern medicine, the cause and mechanism of disease of tinnitus arose from the state of qi-blood deficiency, internal dampness-heat and depression stagnation. In Western medicine, there are mainly caused by damage to the auditory system the lower induced changes in the upper. 2. In Eastern medicine, differentiation of syndromes classifies clinical aspects, and cause and mechanism of disease. In Western medicine, it divides into an generating region, clinical and associated symptoms aspects. 3. In Eastern medicine, internal method of treatments of tinnitus are divided into four treatments. In Western medicine, internal methods of tinnitus are vasodilators, blood-flow improvers, Metabolism improvers etc. 4. In Eastern medicine, external method of treatments of tinnitus are paste preparation method, powder preparation method, pill preparation method, acupuncture & moxibustion method. In Western medicine, external method of treatments of Tinnitus are divided into injection, other surgical therapies and adjuvant therapy. Conclusions : Until now, there is no perfect, effective single treatment. We think that Eastern medicine approach and treatment can be helpful to overcome the limitations of tinnitus cure.

DRA: Duplication Resolver Algorithm for Power Conservation Utilizing Software Defined Network (SDN)

  • Masoud, Mohammad;Jaradat, Yousef;Jannoud, Ismael;Huang, Hong
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제11권7호
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    • pp.3351-3369
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    • 2017
  • In recent years, datacenters, network devices and computers have proliferated. The power consumed by information and communication technology (ICT) devices has inflated in an extraordinary manner. Green communication has emerged as a new approach to reduce and optimize power consumption in ICT sector. Many methods and protocols have been proposed and implemented to achieve green communication. Nevertheless, the increase of power consumption remains a problem. In this work, we attempt to reduce and optimize power consumption of network devices in datacenters environment utilizing software defined network (SDN) paradigm. To gain more insight of the power consumption requirements of network switches, a power measurement system is constructed to measure power consumption levels of network devices. Subsequently, we propose a duplication resolver algorithm (DRA) to power off/on switches reactively. DRA algorithm reduces the required time by switches to construct their flow tables after rebooting. To this end, DRA-based external circuit has been constructed utilizing Ethernet module and an Arduino kit to control power supplies of network devices. To facilitate our work, a testbed has been constructed utilizing Ryu SDN controller, HP2920-24G switches and Arduino kits. Our results show that DRA algorithm can reduce both the power usage and start-up time delay of network switches after failures.

Estimation of Conductivity Tensor of Fractured Rocks from Single-hole Packer test (단정 주입시험 결과를 이용한 단열암반의 수리전도도 분석)

  • 장근무;이은용;김창락;이찬구;김현주
    • The Journal of Engineering Geology
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    • 제10권1호
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    • pp.13-25
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    • 2000
  • A three-dimensional discrete fracture network model based on probabilistic characteristics of fracture geometry and transmissivity was designed to calculate the conductivity tensor and to estimate theanisotropy of conductivity. The conductivities, $K_p$, obtained from the numerical simulation of single-holepacker test corresponded well to those from the field tests. From this, it can be concluded that thefracture network model designed in this study can represent hydraulic characteristics of in-situ fractured rock mass. Block-scale conductivities, $K_b$, estimated from the modelling of steady-state flow through the REV-scale block were ranged between the arithmetic mean and harmonic mean of theconductivity estimates from packer tests. The conductivity along north-south direction was 1.4 timesgreater than that along the east-west direction. It was concluded that the anisotropy of conductivitywas insignificant. It was also found that there was a little correlation between $K_b$ and $K_p$. This would be to that the conductivities from the packer test simulation was strongly dependent on thetransmissivity and the number of fractures within the packer test intervals.

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A Study about Microbiological Quality and Safety Control of a Central Commissary School Foodservice System in Daejeon City Area (대전지역 도시형 공동조리교 급식의 미생물적 품질관리에 관한 연구)

  • Kim, Heh-Young;Jeong, Hyo-Jin
    • Journal of the Korean Society of Food Culture
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    • 제10권1호
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    • pp.67-74
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    • 1995
  • This study researched microbial change of quality according to the various phases of product flow of cooked pea and rice, cold cucumber and seaweed soup, soybean sprouts japchae feeding urban type of a commissary school and a satellite school in Daejeon area, also it suggested the possibility that the central commissary foodservice system can be established and utilized more developmental to identify its food of variation of temperature and state of safety unitl 3 hours after cooking for the case of delay of distribution and holding because of the satellite school of geographical location and traffic problem. The critical Control Points identified for each category of menu items were: Boiled pea and rice: inadequate distribution, holding and storing before assembly; Cold cucumber and seaweed soup: pre-preparation and post-preparation after cooking; Soybean sprouts japchae: Pre-preparation, post-preparation and storing. As the result of observation of the variation of temperature and microbial safety according to the delay of distribution and holding for each food, all of them were relatively safe until 3 hours after cooking, but cold cucumber and seaweed soup being stored for 3 hours, the value of E. coli is $10^3$ CFU/g. The variation of temperature was more extreme in soybean sprouts japchae than cooked pea and rice and cold cucumber and seaweed soup. It was proved that the stainless container was excellent and that adequate holding container should be used.

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The Effect of Jininwhachul-tang-ga-wasong on the Hepatic Cancer in Mouse by N-Nitrosodiethylamine (진인화철탕가와송(眞人化鐵湯加瓦松)이 N-Nitrosodiethylamine으로 유발된 흰쥐의 간암에 미치는 영향)

  • Lim, Dong-Seok;Choi, Chang-Won
    • The Journal of Internal Korean Medicine
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    • 제29권3호
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    • pp.582-594
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    • 2008
  • Objective : The purpose of our study was to investigate the effect of JinlnWhaChul-tang-ga-wasong (JIN) on NDEA-induced liver tumorigenesis. Materials and Methods : We investigated the possible protective effects of Jininwhachul-tang-ga-wasong (JIN) as an anticancer against NDEA-induced liver injury in mice. Experimental mice were classified into 3 groups; normal, saline administered group (control group), and JIN extract (0.15g/kg/every other day) administered group (JIN group) after being injected with NDEA over 12 weeks. We examined the state of differentiation of these tumors and the effects of JIN after 6 weeks. To confirm the induction of apoptosis, the cells were analyzed by terminal deorynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay, acridine orange staining and flow cytometric analysis. To investigate inhibitory effect on the expression of COX-2 by JIN, we performed COX-2 immunohistochemistry and reverse transcription polymerase chain reaction analysis. Results : Body weights significantly decreased in the control and JIN groups compared with the normal group. The levels of cholesterol, hemoglobin and testosterone decreased in the control compared with the normal group. The level of estradiol significantly increased in the control compared with the normal group. The control group reacted with TUNEL assay more than the normal and JIN groups. Upon naked eye, light and electron microscopic examination, JIN improved the morphological and histopathological changes of the liver caused by NDEA-induced hepatic neoplasm. COX-2 immunoreactivity decreased in the JIN group compared with the control group, mRNA expression of the control group was greater than the normal and JIN groups. Conclusion : these results suggest the possibility that JIN may exert an anti-tumor effect on NDEA-induced liver tumorigenesis.

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Psychoacoustical Study for Sound Quality Index of Steady State Noise of Refrigerators (냉장고 정상상태 소음의 음질 인덱스 개발을 위한 심리음향학적 연구)

  • Kong, Kyung-Soo;Jung, Weui-Bong;Kim, Tae-Hoon;Shin, Dae-Sik;Ahn, Se-jin
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • 제26권5호
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    • pp.536-545
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    • 2016
  • Household refrigerator radiates noise of which the pattern is dependent on the operating condition of its parts, such as compressor, flow fans, etc. Thus the refrigerator noise has a variety of frequency characteristics. Therefore, it is required to consider the noise characteristics for evaluating the noise quality and eventually developing the sound quality index of the refrigerator noise. In this study, five units of household refrigerator were selected to measure their noises that were used to generate sound sources for jury test of the study. The measured noises of five refrigerators were divided into ten kinds of sound source by considering operating condition and frequency characteristics. Additionally, the ten sources were each edited to have the same SPL of 30 dBA. Totally twenty kinds of sound sources (10-original SPL, 10-edited SPL 30 dBA) were evaluated by twenty-two subjects, and compared with their sound quality metrics. It was found that only the loudness of the metrics was meaningfully correlated with the subjective evaluation. The rests, sharpness, roughness and fluctuation strength, were not related. The conclusion of this study is that a new sophisticated index is necessary to be developed to qualitatively evaluate the household refrigerator noise.

Study on the Perception of the Human Body in "Huangdineijing" Viewed from the Perspective of the Correspondence between Nature and Human (천인상응(天人相應)의 관점에서 바라본 "황제내경(黃帝內經)"의 인체관 연구)

  • Im, Chae Kwang
    • Journal of Physiology & Pathology in Korean Medicine
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    • 제26권6호
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    • pp.855-863
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    • 2012
  • The organic and holistic recognition method about nature in east asian philosophy is also applied to the study of the human body in Korean medicine. In Korean medicine, the human body is being understood from a holistic point of view rather than a mechanical or reductive one. The main east asian philosophies are the heavens thought and the Yin-yang/Five Phase Theory. This study will explore the influence the general flow of heavens thought has on explaining the human body in Korean medicine and the formation of how the human body is perceived in "Huangdineijing"(黃帝內經). First, the primitive meaning of heaven was developed to include the natural heaven of Xia (夏), the lord heaven of Shang(商) and the moral heaven of Zhou(周) dynasties. Among these, the natural heaven notion of the Xia(夏) dynasty which recognized heaven as the one with the power to create everything. This was followed by Taoism which established the contrasting system of heaven and earth. Based on this, "Huangdineijing"(黃帝 內經) developed the perception of the human body, taking into account, heaven as the original substance to generate the human body through the mutual sympathy between heavenly energy and earthly form. The perspective of the correspondence between nature and human in "Huainantzu"(淮南子) and "L$\breve{u}$shichunqiu"(呂氏春秋) was succeeded by Tung Chung-Shu(董仲舒). Based on this development, the perception of the human body in "Huangdineijing"(黃帝內經) is related to the seasonal cycle and the notion of night and day to balance the physiology of the human body. It recognizes that its structure, shape, emotional state and physiological actions are correlated with heaven.