• Title/Summary/Keyword: active cooling

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Review on Geumnaeng Method - Focus on Chinese Medical Articles - (금냉법(金冷法)에 대한 고찰 - 중국 논문을 중심으로 -)

  • Park, Haemo
    • Journal of Society of Preventive Korean Medicine
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    • v.22 no.3
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    • pp.73-81
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    • 2018
  • Objectives : 'Geumnaeng method'' is a well-known folk remedy, but It has not been studied in academia. This study was conducted to review the chinese published articles on Geumnaeg method (Jinleng method) of Chinese traditional medicine. Methods : The author searched Chinese published papers from 2000 to 2018 via CNKI(China National Knowledge Infrastructure) database by using keyword 'Jinleng', 'Jinleng method', and analyzed the papers covered Jinleng method health preservation, and classified them including periods, type of study, target symptoms, and comparison between countries. Results : 17 studies were reviewed. The study of Jinleng method in China began in 2005. 8 articles (47.1%) were review articles, 4 articles (23.5%) of the case report and case series, and 5 articles (29.4%) were clinical studies. Clinical studies have increased since 2008. Most of the studies related to genital disorders and sexual function were mainly performed. There were differences between Japan, Korea and China in Jinleng method. Conclusions : Various disease and symptoms was researched with Jinleng method in China. Research in China is more active than other country. We need to increase the level of evidence of Jinleng method's effectiveness through additional studies in the future.

Measurement of Laminar Burning Velocity of Endothermic Fuel Surrogates (흡열분해 모사연료의 층류화염 전파속도 측정)

  • Jin, Yu-In;Lee, Hyung Ju;Han, Jeongsik
    • Journal of the Korean Society of Propulsion Engineers
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    • v.23 no.3
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    • pp.67-75
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    • 2019
  • The laminar burning velocity of endothermic fuel surrogates is measured in this study, in order to investigate combustion characteristics of aviation fuel after being used as coolant in an active cooling system of a hypersonic flight vehicle. A Bunsen burner was manufactured such that the laminar burning velocity can be taken for two types of surrogate fuels, SF-1 and 2. The results showed that the burning velocity of surrogate fuels was faster at high equivalence ratio conditions than that of the reference fuel (RF), and specifically, the velocity of SF-1 had the maximum value at the highest equivalence ratio compared with those of SF-2 and RF.

Dual effects of ram pressure on star formation in multiphase disk galaxies with strong stellar feedback

  • Lee, Jaehyun;Kimm, Taysun;Katz, Harley;Rosdahl, Joakim;Devriendt, Julien;Slyz, Andrianne
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.1
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    • pp.28.2-28.2
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    • 2021
  • We investigate the impact of ram pressure stripping due to the intracluster medium (ICM) on star-forming disk galaxies with a multiphase interstellar medium maintained by strong stellar feedback. We carry out radiation-hydrodynamic simulations of an isolated disk galaxy embedded in a 1011 M⦿ dark matter halo with various ICM winds mimicking the cluster outskirts (moderate) and the central environment (strong). We find that both star formation quenching and triggering occur in ram pressure-stripped galaxies, depending on the strength of the winds. HI and H2 in the outer galactic disk are significantly stripped in the presence of moderate winds, whereas turbulent pressure provides support against ram pressure in the central region, where star formation is active. Moderate ICM winds facilitate gas collapse, increasing the total star formation rates by ~40% when the wind is oriented face-on or by ~80% when it is edge-on. In contrast, strong winds rapidly blow away neutral and molecular hydrogen gas from the galaxy, suppressing star formation by a factor of 2 within ~200 Myr. Dense gas clumps with nH≳10 M⦿ pc-2 are easily identified in extraplanar regions, but no significant young stellar populations are found in such clumps. In our attempts to enhance radiative cooling by adopting a colder ICM of T=106K only a few additional stars are formed in the tail region, even if the amount of newly cooled gas increases by an order of magnitude.

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Ram pressure stripping conditions : Theory vs. Observation

  • Lee, Seona;Sheen, Yun-Kyeong;Yoon, Hyein;Jaffe, Yara;Chung, Aeree
    • The Bulletin of The Korean Astronomical Society
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    • v.45 no.1
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    • pp.33.1-33.1
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    • 2020
  • Ram pressure stripping (RPS) which is known to be one of the key effects that can remove the interstellar gas in the dense environment, can be described as a simple momentum transfer relation (Gunn & Gott 1972). However, it has been suggested that the actual gas stripping process is likely more complicated than Gunn & Gott's prescription due to the complexity of gas physics such as compression, cooling and heating. By comparing the gas truncation radius predicted by theory with the stripping radius measured from the HI observation of Virgo cluster galaxies, we attempt to verify how well the RPS process can be understood by momentum transfer alone. Among the sample of galaxies undergoing active RPS, we generally find a good agreement between what is predicted and what is observed within the measurement uncertainties. However, those galaxies with the signs of other environmental effects than RPS such as tidal interaction, and/or the ones likely at relatively early or later stages of RPS show some offsets between the theory and the observation. These results imply that Gunn & Gott's formula works reasonably well in a broad sense when the RPS is a dominant process and the surrounding environment at the current location of the sample can be well defined. Otherwise, the impact of the second mechanism, as well as the (current and past) environment of the sample, should be more carefully reviewed to assess the impact of RPS on galaxy evolution.

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Management of a trauma patient with alcohol withdrawal who developed neuroleptic malignant syndrome in Korea: a case report

  • Byungchul Yu;Ji Yeon Lee;Yong Beom Kim;Hee Yeon Park;Junsu Jung;Youn Yi Jo
    • Journal of Trauma and Injury
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    • v.36 no.3
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    • pp.249-252
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    • 2023
  • Neuroleptic malignant syndrome (NMS) is a rare but fatal condition, with a high mortality rate. NMS is characterized by altered mental status, fever, myoclonus, autonomic dysfunctions, and elevated creatinine phosphokinase. The clinical manifestations may be confused with alcohol-related symptoms, trauma, sepsis, postoperative agitation, or malignant hyperthermia. A 69-year-old male patient with alcohol withdrawal was admitted to the operating theatre to rule out septic shock due to mesenteric injury after multiple trauma. He was suspected NMS with abrupt increase body temperature to 41.7℃ after haloperidol administration. Active cooling and rapid fluid infusion was done during anesthesia. Delayed diagnosis and treatment of NMS lead to catastrophic result. Therefore, if the patient's past medical history is unknown or clinical symptoms develop that are suggestive of NMS, early treatment must be considered.

Active-Sensing Based Damage Monitoring of Airplane Wings Under Low-Temperature and Continuous Loading Condition (능동센서 배열을 이용한 저온 반복하중 환경 항공기 날개 구조물의 손상 탐지)

  • Jeon, Jun Young;Jung, Hwee kwon;Park, Gyuhae;Ha, Jaeseok;Park, Chan-Yik
    • Journal of the Korean Society for Nondestructive Testing
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    • v.36 no.5
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    • pp.345-352
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    • 2016
  • As aircrafts are being operated at high altitude, wing structures experience various fatigue loadings under cryogenic environments. As a result, fatigue damage such as a crack could be develop that could eventually lead to a catastrophic failure. For this reason, fatigue damage monitoring is an important process to ensure efficient maintenance and safety of structures. To implement damage detection in real-world flight environments, a special cooling chamber was built. Inside the chamber, the temperature was maintained at the cryogenic temperature, and harmonic fatigue loading was given to a wing structure. In this study, piezoelectric active-sensing based guided waves were used to detect the fatigue damage. In particular, a beamforming technique was applied to efficiently measure the scattering wave caused by the fatigue damage. The system was used for detection, growth monitoring, and localization of a fatigue crack. In addition, a sensor diagnostic process was also applied to ensure the proper operation of piezoelectric sensors. Several experiments were implemented and the results of the experiments demonstrated that this process could efficiently detect damage in such an extreme environment.

Study on the Standardization of a Surveillance Culture Laboratory in Infection Control Fields (감염관리 분야에서 감시배양검사의 표준화 연구)

  • Park, Chang-Eun;Jeong, Na-Yeon;Yang, Min-Ji;Kim, Han-Wool;Joo, Sei-Ick;Kim, Keon-Han;Seong, Hee-Kyung;Hwang, Yu-Yean;Lim, Hyun-Mi;Son, Jae-Cheol;Yoon, Sun-Han;Yoon, Nam-Seob;Jang, In-Ho
    • Korean Journal of Clinical Laboratory Science
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    • v.50 no.3
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    • pp.359-369
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    • 2018
  • An essential measure to prevent healthcare-associated infections (HAI) is to develop a consistent system of surveillance, thereby promoting a reliable situation diagnosis to perform efficient control for the problem. Patient-to-patient transmission of pathogens within the hospital plays a substantial role in the epidemiology of HAIs. Contamination of healthcare environments commonly occurs, including facilities surfaces (e.g., bed rails, bedside tables), drinking water, cooling tower water, endoscopic instruments, food, airborne, endotoxin test, sterile test and medical equipment, with pathogenic organisms. In addition, epidemiological analysis is performed by multi locus sequence tying, pulsed-field gel electrophoresis for active surveillance. Therefore, an environmental surveillance culture test for prevention improves patient safety and blocks infection agents. Effective infection control and increased safety are possible by controlling the national infection control system. In conclusion, this study contributes to an effective infection control system through the standardization of active surveillance culture laboratory and secure expertise as infection control specialist. The primary objective of the standardization is to improve the safety of the nation's healthcare system by reducing the rates of HAIs.

Development of Planar Active Electronically Scanned Array(AESA) Radar Prototype for Airborne Fighter (항공기용 평면형 능동 전자주사식 위상 배열(AESA) 레이더 프로토 타입 개발)

  • Chong, Min-Kil;Kim, Dong-Yoon;Kim, Sang-Keun;Chon, Sang-Mi;Na, Hyung-Gi
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.12
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    • pp.1380-1393
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    • 2010
  • This paper presents a design, fabrication and the test results of planar active electronically scanned array(AESA) radar prototype for airborne fighter applications using transmit/receive(T/R) module hybrid technology. LIG Nex1 developed a AESA radar prototype to obtain key technologies for airborne fighter's radar. The AESA radar prototype consists of a radiating array, T/R modules, a RF manifold, distributed power supplies, beam controllers, compact receivers with ADC(Analog-to-Digital Converter), a liquid-cooling unit, and an appropriate structure. The AESA antenna has a 590 mm-diameter, active-element area capable of containing 536 T/R modules. Each module is located to provide a triangle grid with $14.7\;mm{\times}19.5\;mm$ spacing among T/R modules. The array dissipates 1,554 watts, with a DC input of 2,310 watts when operated at the maximum transmit duty factor. The AESA radar prototype was tested on near-field chamber and the results become equal in expected beam pattern, providing the accurate and flexible control of antenna beam steering and beam shaping.

THE MILLIMETER-RADIO EMISSION OF BL LACERTAE DURING TWO γ-RAY OUTBURSTS

  • Kim, Dae-Won;Trippe, Sascha;Lee, Sang-Sung;Park, Jong-Ho;Kim, Jae-Young;Algaba, Juan-Carlos;Hodgson, Jeffrey A.;Kino, Motoki;Zhao, Guang-Yao;Wajima, Kiyoaki;Kang, Sincheol;Oh, Junghwan;Lee, Taeseok;Byun, Do-Young;Kim, Soon-Wook;Kim, Jeong-Sook
    • Journal of The Korean Astronomical Society
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    • v.50 no.6
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    • pp.167-178
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    • 2017
  • We present a study of the inexplicit connection between radio jet activity and ${\gamma}$-ray emission of BL Lacertae (BL Lac; 2200+420). We analyze the long-term millimeter activity of BL Lac via interferometric observations with the Korean VLBI Network (KVN) obtained at 22, 43, 86, and 129 GHz simultaneously over three years (from January 2013 to March 2016); during this time, two ${\gamma}$-ray outbursts (in November 2013 and March 2015) can be seen in ${\gamma}$-ray light curves obtained from Fermi observations. The KVN radio core is optically thick at least up to 86 GHz; there is indication that it might be optically thin at higher frequencies. To first order, the radio light curves decay exponentially over the time span covered by our observations, with decay timescales of $411{\pm}85$ days, $352{\pm}79$ days, $310{\pm}57$ days, and $283{\pm}55$ days at 22, 43, 86, and 129 GHz, respectively. Assuming synchrotron cooling, a cooling time of around one year is consistent with magnetic field strengths $B{\sim}2{\mu}T$ and electron Lorentz factors ${\gamma}$ ~ 10 000. Taking into account that our formal measurement errors include intrinsic variability and thus over-estimate the statistical uncertainties, we find that the decay timescale ${\tau}$ scales with frequency ${\nu}$ like ${\tau}{\propto}{\nu}^{-0.2}$. This relation is much shallower than the one expected from opacity effects (core shift), but in agreement with the (sub-)mm radio core being a standing recollimation shock. We do not find convincing radio flux counterparts to the ${\gamma}$-ray outbursts. The spectral evolution is consistent with the 'generalized shock model' of Valtaoja et al. (1992). A temporary increase in the core opacity and the emergence of a knot around the time of the second ${\gamma}$-ray event indicate that this ${\gamma}$-ray outburst might be an 'orphan' flare powered by the 'ring of fire' mechanism.

An Analysis on the Temperature Safety of a Boiler Desuperheater (보일러 과열증기 냉각기의 온도 안전성에 관한 연구)

  • Ha, Ji-Soo;Kim, Tae-Kwon;Chang, Hyuk-Sang
    • Journal of the Korean Institute of Gas
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    • v.16 no.2
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    • pp.9-13
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    • 2012
  • The present study has been carried out to diagnose the temperature safety of a boiler desuperheater which decreases abnormally higher temperature of superheated steam in a reheater of a power plant. The liquid water in the desuperheater stays in a closed space. It becomes heated by the high temperature superheated steam and boiling could occur. Boiling might increase internal pressure and it could destroy the desuperheater if the internal pressure exceeds the allowable pressure of the desuperheater. The present study modeled reasonably the desuperheater and four cases of heat transfer analysis are executed with the consideration of insulator and natural convective fluid flow of the inside cooling water. For the case excluded the natural convective fluid flow, the temperature exceeds the allowable temperature and pressure. On the other hand, for the real case included natural convective fluid flow and insulator, the active heat transfer from higher temperature region to lower temperature region occurs and it makes the temperature in the cooling water below the allowable temperature and pressure. From this fact, it could be thought that the desuperheater in the reheater is safe from destroy or back flow.