• Title/Summary/Keyword: Cold flow

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Construction and Assembly of KSTAR Current Leads and the Helium Control System (KSTAR 전류인입선 및 헬륨냉매 제어시스템 제작 및 설치)

  • Song, N.H.;Woo, I.S.;Lee, Y.J.;Kwag, S.W.;Bang, E.N.;Lee, K.S.;Kim, J.S.;Jang, Y.B.;Park, H.T.;Hong, J.S.;Park, Y.M.;Kim, Y.S.;Choi, C.H.
    • Journal of the Korean Vacuum Society
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    • v.16 no.5
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    • pp.388-396
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    • 2007
  • KSTAR (Korea Superconducting Tokamak Advanced Research) current lead system (CLS) has a role to interconnect magnet power supply (MPS) in room temperature (300 K) and superconducting (SC) bus-line, electrically. For the first plasma experiments, it should be assembled 4 current leads (CL) on toroidal field (TF) current lead box (CLB) and 14 leads on poloidal field (PF) CLB. Two current leads, with the design currents 17.5 kA, and SC bus-lines are connected in parallel to supply 35 kA DC currents on TF magnet. Whereas, it could supply $20\;{\sim}\;26\;kA$ to each pairs of PF magnets during more than 350 s. At the cold terminals of the leads, there are joined SC bus-lines and it was constructed helium coolant control system, aside from main tokamak system, to protect heat flux through current leads and enhanced Joule heat due to supplied currents. Throughout the establishment processes, it was tested the high vacuum pumping, helium leak of the helium lines and hardwares mounted between the helium lines, flow controls for CL, and liquid nitrogen cool-down of possible parts (current leads, CL helium lines, and thermal shield helium lines for CLB), for the accomplishment of the required performances.

Study on the 'Diagnosis and Treatment of the Woman Various Diseases' in Synopsis Golden Chamber (금궤요략${\cdot}$부인잡병맥증병치제이십이(婦人雜病脈證幷治第二十二)에 대(對)한 연구(硏究))

  • Lee, Tae-Ho;Lim, Dong-Kook;Koh, Seung-Wook;Jeong, Heon-Young;Keum, Kyoung-Su
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.22 no.1
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    • pp.32-50
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    • 2008
  • This study is concerned with examining the causes and symptoms of Woman various diseases and clearing up the situations of pulses and their treatment. Woman various diseases are said to be various kinds of diseases including the disorder of menstruation and genitals except pregnancy and postpartum diseases. The main contents are the penetration of heat into worm, the discharge of much blood, stomachache, and the postpartum cyst diseases. Among them, the nature of the diseases which often occur in the gynecology, such as the menstrual diseases and stomachache, were described comparatively in detail. The reason why heat penetrates into the worm is that the external germs come into it under its weakness. To treat it, heat should be removed and lumping blood should be sent out of body. Especially only after whether the disease is serious or not is examined, and just after the process of the disease is examined, the lumping blood can be eliminated. The ways to cure it by sweating a patient too much, getting him or her to vomit, or forcing him or her to be urinated too much, should be avoided. The disorder of menstruation, as the disease which most often occur among the diseases of gynecology, includes menstrual irregularity and blood discharge, and non-menstruation. Among them, non-menstruation and blood discharge are comparatively often discussed. When they are treated, lumping blood and cold energy should be cured well through getting rid of the lumping blood and making the blood vessel flow well. The difficult urination after childbirth, which comes from the weak urinary cist, makes symptoms such as the stuffy chest, the difficulty of lying down, and breathing with his or her back something. To urinate better, the ability of the urinary cist should be supplemented and improved. The principle of the treatment for Woman various diseases is to examine the situation of the pulse closely, then set up the way to treat it, and prescribe a patient. In this study, besides the treatment of Chinese herb medicine, the medicine for washing genitals and the medicine placed in the worm were used to cure Woman various diseases. This treatment is the beginning of the surgical treatment in the gynecology.

A Study on Tree-ring Dating and Speciation of Charcoal found in Pumiceous Deposit of the Quaternary Nari Caldera, Ulleung Island, Korea (신생대 제4기 울릉도 나리칼데라 부석층에서 산출된 탄화목의 연륜연대 및 수종식별 연구)

  • Im, Ji Hyeon;Choo, Chang Oh
    • Economic and Environmental Geology
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    • v.48 no.6
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    • pp.501-508
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    • 2015
  • The purpose of this study is to provide an inquiry into paleovegetation (paleoenvironment), eruption age and inferred emplacement temperature of pyroclastic deposit using charcoal occurred in the Quaternary Nari Caldera, Ulleung Island. In order to obtain the data, we carried out species identification and tree-ring analysis, radiocarbon dating for the charcoal. This sample was collected from pumiceous deposit in lowermost member(Member N-5) of the Nari Tephra Formation, which corresponds to the wood branch that has well preserved the tree-ring structure. Speciation and outermost tree-ring of wood reveal Picea spp. and $263+{\alpha}$ years. The calibrated ages from the center(pith) to the outermost tree-ring are $20,260{\pm}230$, $19,995{\pm}245$, and $19,975{\pm}265cal\;BP$, respectively, which are accordant with the tree-ring position. The youngest age, <19,710 cal BP would have implications for the eruptive age of Member N-5. Our results indicate that Picea spp. is the paleovegetation representing that Nari Caldera was under cold and wet climate conditions during the late Pleistocene. Based on the silky luster, brittleness, color, and streak of charcoal, etc., the lowest emplacement temperatures of pyroclastic flow are interpreted to have been at least as high as $350{\sim}500^{\circ}C$.

Effect of Moisture Content on Viscosity of Starch Dough (전분반죽의 점도에 미치는 수분함량의 영향)

  • Lee, Boo-Yong;Lee, Chang-Ho;Lee, Cherl-Ho
    • Korean Journal of Food Science and Technology
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    • v.27 no.4
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    • pp.582-592
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    • 1995
  • To measure rheological properties of the starch dough, an Extrusion Capillary Viscometer(ECV) cell was self-made and attached to Instron machine(Model 1140). Apparent viscosities of corn and waxy corn starch doughs were measured and their gelatinization degrees were determined by enzymatic analysis. When corn and waxy corn starch doughs with $36{\sim}52%$ moisture content were heated at $60{\sim}100^{\circ}C$, come-up time of the cold point of doughs decreased from 220 sec to 140 sec with increased in the moisture content. In the measurement range of $36{\sim}52%$ moisture content and $60{\sim}100^{\circ}C$ heating temperature, both corn and waxy corn starch doughs showed pseudoplastic flow behaviors. At the same shear rate, both shear stress and viscosity of starch dough decreased as the moisture content increased. At the moisture content above 44%, the shear stress and viscosity of starch dough decreased as the heating temperature increased from $60^{\circ}C\;to\;70^{\circ}C$, but increased as the heating temperature increased from $80^{\circ}C\;to\;100^{\circ}C$. When the moisture content increased and heating temperature, the gelatinization degree of starch dough increased from about 10% to about 62%. The gelatinization degree of waxy corn starch dough was $15{\sim}20%$ higher than that of corn starch dough under the same gelatinization conditions. The effects of moisture content on the viscosity of starch dough were examined by Arrhenius equation. As the moisture content increased, viscosity of starch dough decreased. But the effect of moisture content was greater in the range of $80{\sim}100^{\circ}C$ than in the range of $60{\sim}70^{\circ}C$ heating temperature.

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Observational Characteristics of East Asian Monsoon during the Summers of 1993 and 1994 (1993, 1994년 여름철 동아시아몬순의 관측 특성)

  • Kim, Baek-Jo;Ryu, Chan-Su
    • Journal of the Korean earth science society
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    • v.23 no.4
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    • pp.369-379
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    • 2002
  • The characteristics of the East Asian summer monsoon circulation associated with the cool and wet summer of 1993 and the warm and dry summer of 1994 are investigated by analyzing the atmospheric circulations features in the upper and lower troposphere and by examining the global SST and associated tropical convective precipitation fields. The negative geopotential height anomalies at 500 hPa and 200 hPa in 1993 over East Asia, the central North Pacific, and the western United States were replaced by positive ones in 1994. In addition, the 200 hPa zonal wind anomaly averaged over the East Asian summer monsoon region is negatively correlated with the Korean summer temperature anomaly. The subtropical jet stream in 1993 was displaced into the central part of Korea well south of its normal position. The western Pacific subtropical high was shifted southward, and the East Asian summer rainfall and temperature was above-normal and below-normal, respectively due to the southwestward extension of a cold and dry polar airmass from the Sea of Okhotsk to the Est Sea. In contrast, the subtropical jet stream in 1994 was displaced well north of its normal position. The abrupt northward shift of the western Pacific subtropical high was accompanied with the rapid northward movement of the rain band of the East Asian summer monsoon rainfall. The anomaly patterns of the East Asia summer rainfall and temperature were opposite to those of 1993. Large sea surface temperature anomalies of opposite signs existed in the tropical Pacific with a mature El $Ni{\~{n}o$ in 1993 and a weak La $Ni{\~{n}a$ condition in 1994. The role of the anomalous convective precipitation in the western Pacific and the Indian Ocean related with the variations in the low-level cross-equatorial flow along the northwestern periphery of the Australian high and the Mascarene high is probably to influence a large-scale atmospheric circulation over the East Asia during both the years.

A study of the Mori Radicis Cortex pre-treatment on transient ischemic brain injury in mice (상백피(桑白皮) 메탄올 추출물 전처치가 일과성 허혈에 의한 생쥐의 뇌 손상에 미치는 영향)

  • Chung, Byung-Woo;Lim, Jae-Yu;Lee, Se-Eun;Lee, Byoungho;Lim, Sehyun;Lim, Chiyeon;Cho, Suin
    • The Korea Journal of Herbology
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    • v.32 no.1
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    • pp.25-31
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    • 2017
  • Objectives : Mori Radicis Cortex (MRC), the root epidermis of Morus alba L., has been traditionally used to treat lung-related diseases in Korean Medicine. The common of MRC is Mulberry bark Morus bark, and it's pharmaceutical properties and taste are known as sweet and cold, and it promotes urination and reduce edema by reducing heat from the lungs and soothe asthma. In the present study, anti-apoptotic mechanism of MRC in middle cerebral artery occlusion (MCAO) model in mice. Methods : Two-hundred grams of MRC was extracted with methanol at room temperature for 5 days, and this was repeated one time. After filtration, the methanol was removed using vacuum evaporator, then stored at $-20^{\circ}C$ until use. C57BL/6 male mice were housed in an environment with controlled humidity, temperature, and light cycle. In order to determine beneficial effects of MRC on ischemia induced brain damage, infarct volume, neurological deficit scores, activities of several apoptosis-related proteins such as caspase-8, -9, Bcl-xL in MCAO-induced brains of mice were analyzed. Mice in MRC-treated groups were orally administered 30, 100, or 300 mg/kg of body weight for three consecutive days before commencing the MCAO procedure. Results : Pre-treatment of MRC significantly reduced infarct volume in MCAO subjected mice applied with 300 mg/kg of MRC methanol extract, and MRC effectively inhibited Bcl-xL reduction and caspase-9 activation caused by MCAO-induced brain damage. Conclusions : MRC showed neuro-protective effects by regulating apoptosis-related protein signals, and it can be a potential candidate for the therapy of ischemia-induced brain damage.

TREATMENT OF COMPOSITE RESIN RESTORATION WITH THE AIR ABRASIVE TECHNIQUE (Air abrasive technique을 이용한 복합레진 수복 증례)

  • Lee, Chang-Woo;Jang, Ki-Taeg;Lee, Sang-Hoon;Hahn, Se-Hyun
    • Journal of the korean academy of Pediatric Dentistry
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    • v.24 no.4
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    • pp.763-770
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    • 1997
  • The air abrasive technique is a non-mechanical method by which teeth are treated before restoration and stains and calculi are removed from tooth surfaces using the kinetic energy of small particles. The air abrasive technique in dentistry was first introduced in the 1950's with as instrument called 'Airdent'. But, as the main restorative materials of the period were amalgam and gold, and the instrument's inability to control the flow of particles caused the particles to be spread throughout the clinics, widespread use was not possible. In the 1990's, as these techincal problems were solved and more interest in new restorative materials rose in an effort to preserve sound tooth structure, new developements took place in instruments related to the air abrasive technique. The air abrasive technique produces less pressure, vibration and heat that might cause patient discomfort and facilitates the preservation of sound tooth structure. It also reduces the need for anesthesia and is less harmful to the pulp. Other advantages include increase in dentin bonding strength of composite resin, lower possibility of saliva contamination and maintenance of a dry field. But there is not direct contact between the nozzle and the tooth, the operator cannot use his or her tactile sense and must rely solely upon visual input. Other disadvantages are: the tooth preparation depends on the operator's ability; alpha-alumina particles, after bouncing off the tooth surface, cause damage to dental mirrors; the equipment is expensive and takes up a certain amount of space in the clinic. The author conducted case report using the air abrasive technique on patient visiting the Department of Pediatric Dentistry at Seoul National University Dental Hospital and arrived at the following conclusions. 1. The tooth preparation capability of different air abrasive devices varied widely among manufacturers. 2. It was more effective in treating early caries lesions and stains compared to lesions where caries had already progressed to produce soft dentin. 3. The cold stream and noise caused by the evacuation system was a major cause of discomfort to pediatric patients. 4. As there is no direct contact with tooth surface when using the air abrasive technique for tooth preparation, considerable experience and skill is required for proper tooth preparation.

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Comparative Experiments to Assess the Effects of Accumulator Nitrogen Injection on Passive Core Cooling During Small Break LOCA

  • Li, Yuquan;Hao, Botao;Zhong, Jia;Wang, Nan
    • Nuclear Engineering and Technology
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    • v.49 no.1
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    • pp.54-70
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    • 2017
  • The accumulator is a passive safety injection device for emergency core cooling systems. As an important safety feature for providing a high-speed injection flow to the core by compressed nitrogen gas pressure during a loss-of-coolant accident (LOCA), the accumulator injects its precharged nitrogen into the system after its coolant has been emptied. Attention has been drawn to the possible negative effects caused by such a nitrogen injection in passive safety nuclear power plants. Although some experimental work on the nitrogen injection has been done, there have been no comparative tests in which the effects on the system responses and the core safety have been clearly assessed. In this study, a new thermal hydraulic integral test facility-the advanced core-cooling mechanism experiment (ACME)-was designed and constructed to support the CAP1400 safety review. The ACME test facility was used to study the nitrogen injection effects on the system responses to the small break loss-of-coolant accident LOCA (SBLOCA) transient. Two comparison test groups-a 2-inch cold leg break and a double-ended direct-vessel-injection (DEDVI) line break-were conducted. Each group consists of a nitrogen injection test and a nitrogen isolation comparison test with the same break conditions. To assess the nitrogen injection effects, the experimental data that are representative of the system responses and the core safety were compared and analyzed. The results of the comparison show that the effects of nitrogen injection on system responses and core safety are significantly different between the 2-inch and DEDVI breaks. The mechanisms of the different effects on the transient were also investigated. The amount of nitrogen injected, along with its heat absorption, was likewise evaluated in order to assess its effect on the system depressurization process. The results of the comparison and analyses in this study are important for recognizing and understanding the potential negative effects on the passive core cooling performance caused by nitrogen injection during the SBLOCA transient.

An Experimental Study on the Effect of Reduced Slag and Gypsum on Concrete at Low Temperature(-5℃) (저온(-5℃)에서의 환원슬래그 및 석고가 콘크리트에 미치는 영향에 관한 실험적 연구)

  • Kim, Hyeong-Cheol;Choi, Hyun-Kuk;Min, Tae-Beom;An, Dong-Hee;Choi, Si-Hyun;Lee, Han-Seung
    • Journal of the Korea Institute of Building Construction
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    • v.17 no.3
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    • pp.279-285
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    • 2017
  • In this study, the development of concrete preventing initial frost damage and durability about that were evaluated by using anti-aging agent and admixture(reduced slag). As a result of experiment, initial hydration heat was increased by $C_{12}A_7$ of reduced slag components but it was not effective to development of strength. Also fluidity decreased with increasing replacement of reduced slag. This suggested that fluidity was low by rapid setting due to absent of gypsum in reduced slag components. In case of CR2G specimen that added 4% gypsum, the flow ability was higher than plain. It is considered that concrete developed using reduced slag should use $SO_3$. Result of durability experiments, the durability decreased with increasing replacement amount of reduced slag.

Thermal Insulation Effect of Inflatable Life Vest on the Drowned Individual estimated by Numerical Analysis (익수자 체온 저하에 미치는 팽창식 구명동의의 단열효과 수치 분석)

  • Kim, Sung Chan;Lee, Kyung Hoon;Hwang, Se Yun;Lee, Jin Sung;Lee, Jang Hyun
    • Journal of Navigation and Port Research
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    • v.39 no.4
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    • pp.285-291
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    • 2015
  • Exposure to cold sea water can be life-threatening to the drowned individual. Although appropriate life jacket can be usually be provided for the buoyance at the drowning accident, heat loss can make the drowned individual experience the hypothermia. Inflatable life jackets filled with inflatable air pocket can increase the thermal protection as well as the buoyancy force. Because it is important to know how the human body behaves unde the different life jacket, present study compares the thermal insulation capacity of solid type life jacket with that of inflatable life jacket. In order to represent the insulation capacity of life jacket, thermal resistance is estimated based on the assumption of steady-state. Also, a transient three-dimensional thermal distribution of the thigh is analyzed by using finite element method implementing the Pennes bioheat equation. The finite element model is a segmental, multi-layered representation of the body section which considers the heat conduction within tissue, bone, fat and local blood flow rate.