• 제목/요약/키워드: Cold Working

검색결과 325건 처리시간 0.023초

저열유속에서 상변화를 수반하는 메탄의 유동거동특성 (The Flow Behavior Characteristics of Methane with Phase Change at Low Heat Flux)

  • 최부홍
    • 해양환경안전학회지
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    • 제20권1호
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    • pp.96-103
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    • 2014
  • 극저온 액체 상태의 LNG는 주거용과 산업용으로 공급되기 전에 가스 상태로 변환된다. 이러한 재가스화 과정 중에 LNG는 $83.7{\times}10^4$ kJ/kg 정도의 많은 냉열에너지를 제공한다. 이 냉열에너지를 일부 선진국들에서는 질소, 수소, 헬륨과 같은 극저온 유체들의 액화, 제빙 및 냉방시스템에 이용하고 있다. 따라서 우리나라에서도 인천, 평택 및 통영 LNG 인수기지 주변에 LNG의 냉열에너지를 이용한 냉열에너지 회수시스템을 설립할 필요가 있다. 여기서는 저열유속상태에서 상변화를 동반하는 LNG의 유동거동 특성을 파악하기 위해 LNG의 85 %를 차지하는 메탄을 작동유체로 사용하였다. 또한 본 논문은 극저온 열교환기 내부를 흐르는 메탄과 질소, 프로판, R11 및 R134a의 유동경계에 영향을 주는 관 직경, 관의 경사각도 및 포화압력의 효과를 보여준다. 또한 여기서 얻어진 이론적 연구결과와 기존의 실험 데이터와도 비교 되었다. 그리고 메탄의 유동경계에 주는 파이프의 경사각도의 영향은 매우 큼을 알 수 있었다.

산후조리원 이용 산모의 산후조리 인지도와 수행도 (A Study on the Level of Recognition & Performance of Traditional Postpartal Care for postpartal Women in Postpartum Care Center)

  • 박심훈;김현옥
    • 여성건강간호학회지
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    • 제8권4호
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    • pp.506-520
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    • 2002
  • The purpose of this study is to research the degree of recognition & performance of traditional postpartal care for postpartal women and to provide the basic data for improvement of service in a postpartum care center. The respondents of this study were 100 women of 6 postpartum care centers within a C province from Oct. 20 to Dec. 10, 2000. The instruments of measure were used for collecting data on the degree of recognition & performance of traditional postpartal care developed by the researcher. Data analysis consisted of frequency, percentage, mean, standard deviation, paired t-test, t-test, ANOVA which are calculated by Scheffe test and Cronbach's alpha which is used as a reliance level by using a SPSS-PC+. The results of the study were as follows:1. The average score for the degree of recognition of traditional postpartal care(Sanhujori) for postpartal women was $3.09{\pm}.31$, and they recognized that it was important. The methods which were ranked were as follows; Protecting the body from a harmful state, invigorating the body by the argumentation of heat and avoidance of cold, handling with whole heart, and keeping clean, resting without working, eating well. 2. The average score for the degree of performance of traditional postpartal care (Sanhujori) for postpartal women was $2.81{\pm}.31$, and they performed that it was important, too. The methods which were ranked were as follows; Protecting the body from a harmful state, invigorating the body by the augumentation of heat and avoidance of cold, eating well, handling with whole heart, and keeping clean, resting without working. 3. There were significant differences statistically (paired-t=-8.39, p=.000) of the degree of recognition & performance of traditional postpartal care(Sanhujori) for the postpartal women. The degree of recognition was higher than the degree of performance. So, the recognition of traditional postpartal care (Sanhujori) was higher than the performance of it. 4. There were no statistical differences of the degree of recognition & performance of traditional postpartal care(Sanhujori) among the postpartal women's age, religion, job, educational background, delivery frequency, delivery method or the sex of baby. So, the Characteristics of the respondents were not influenced as far as the degree of recognition & performance of traditional postpartal care(Sanhujori). 5. There were significant differences statistically of the degree of performance of traditional postpartal care(Sanhujori) among the 5 postpartum care centers except 1 postpartum care center(p<.01). So, the recognition of traditional postpartal care(Sanhujori) was higher than the performance of traditional postpartal care(Sanhujori) in the 5 postpartum care centers. But there was performed as good as recognition in only 1 postpartum care center.

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3교대 근무여성과 주간 근무여성의 양도락상의 변화와 임상증상의 비교 고찰 (Clinical Study on the Change of Yangdorak and the Clinical Symptoms in Women Who Work in Three Shifts and During the Day)

  • 정재숙;황정선;조영도;김철수;임성민;김형준
    • 동의생리병리학회지
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    • 제18권3호
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    • pp.930-934
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    • 2004
  • The purpose of this research is to evaluate the change of Yangdorak in women who work in three shifts and during the day. In this research, seventy women who work during the day and thirty women who work in three shifts, all of whom are working at Woo shin hyang Oriental Hospital and Kang dong gu Office, were the two subjects for it. We evaluated and compared the Yangdorak appeared in two groups and studied the relations with clinical symptoms between the two. In Yangdorak, the women who work in three shifts were evaluated low numerical value in liver meridian, heart meridian, kidney meridian compared with the women who work during the day. Based on the results above, we can state that the women who work in three shifts suffer from severe dysmenorrhea, insomnia, cold hypersensitivity.

저융점 금속을 사용한 초크랄스키 실리콘 단결정 성장 공정의 열유동 모사 실험 (A Cold model experiment on the thermal convection in the czochralski silicon single crystal growth process)

  • 이상호;김민철;이경우
    • 한국결정성장학회지
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    • 제9권2호
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    • pp.149-156
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    • 1999
  • 초크랄스키 결정성장계의 산소농도에 영향을 주는 유동거동에 대한 정보를 얻기 위해 저온모델을 이용하여 실험적으로 초크랄스키 멜트에 내의 유속을 측정하였다. 실리콘 멜트와 유사한 프란틀(Pr) 수를 갖는 저 융점의 Woods metal을 작동유체로 채택하였다. 전기 전도성을 갖는 유체에서 속도 측정이 가능한 일체형 자석 프로우브(Incorporated magnet probe)를 제작하여 멜트 내부의 여러 지점에서 유속을 3차원저긍로 측정하였다. 측정 결과 관찰된 속도장은 자연대류가 지배적이며 비축대칭적인 유동양상을 나타내었다. 또한 멜트의 두 지점에서 동시에 측정된 온도 데이터로부터 상관계수 및 도가니 회전에 의한 온도 wave의전파를 분석한 결과 상관계수의 크기는 기존의 소형 실리콘 멜트의 연구에서 구한 값보다 작게 나타났으며 이러한 현상은 규모가 큰 멜트의 유동은 난류인 거동이 더 강해지기 때문에 발생하는 것으로 파악되었다.

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종합병원 직원의 기호도 조사 (A Survey of Food Preferences of Employees in Hospital)

  • 백지원;강옥수;이혜진;조영연
    • 대한영양사협회학술지
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    • 제7권4호
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    • pp.385-396
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    • 2001
  • This study was carried out to obtain the menu preferences of frequently served set menu of the staff working at Samsung Medical Center. The frequently served set menus were 72 menus including 23 Korean meals, 12 bowel of rices, 18 noodles, 10 soups, 6 fried rices, 3 western meals. The subjects of this study were 624 staffs who works at Samsung Medical Center. The results are summarized as followers : The subject group for this study was composed of 23% males and 58% females, 80% of subjects are twenties and thirties. The best preferred menu was fried food 4(boiled rice with assorted mixtures, boiled quail egg). And noodles 8(cold buckwheat noodles, fried mung-beans), noodles 2(buckwheat noodles, fried vegetable), Western meals 3(hamburg steak, steamed dumpling), noodles 18(rice-cake dumping soup, fried sweet potato with sugar syrup) were preferred by the subjects. The worst preferred menu was soups 4(loach soup, fried sea food and welsh onion). In the preference each kinds of set menus, Korean meals 3(soup to relive the hangover with pollack, grilled meat, lettuce, fruit salad, Kimchi, ice tea) was the most preferred of the Koreans meals, bowel of rice 8(omelet containing fried rice, chicken salad) of the bowel of rices, noodles 8(cold buckwheat noodles, fried mung-beans) of the noodles, soups 3(spicy beef soup, chicken salad) of the soups, fried rice 5(boiled rice with assorted mixtures, boiled quail egg). There was no significant sexual difference in the menu preferences except 7 menus. There was significant age difference in the 17 menu preference, the younger age subjects were the better like noodles.

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Transcriptome Analysis in Brassica rapa under the Abiotic Stresses Using Brassica 24K Oligo Microarray

  • Lee, Sang-Choon;Lim, Myung-Ho;Kim, Jin A;Lee, Soo-In;Kim, Jung Sun;Jin, Mina;Kwon, Soo-Jin;Mun, Jeong-Hwan;Kim, Yeon-Ki;Kim, Hyun Uk;Hur, Yoonkang;Park, Beom-Seok
    • Molecules and Cells
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    • 제26권6호
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    • pp.595-605
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    • 2008
  • Genome wide transcription analysis in response to stresses is essential to provide the basis of effective engineering strategies to improve stress tolerance in crop plants. In order to perform transcriptome analysis in Brassica rapa, we constructed a B. rapa oligo microarray, KBGP-24K, using sequence information from approximately 24,000 unigenes and analyzed cold ($4^{\circ}C$), salt (250 mM NaCl), and drought (air-dry) treated B. rapa plants. Among the B. rapa unigenes represented on the microarray, 417 (1.7%), 202 (0.8%), and 738 (3.1%) were identified as responsive genes that were differently expressed 5-fold or more at least once during a 48-h treatment with cold, salt, and drought, respectively. These results were confirmed by RT-PCR analysis. In the abiotic stress responsive genes identified, we found 56 transcription factor genes and 60 commonly responsive genes. It suggests that various transcriptional regulatory mechanisms and common signaling pathway are working together under the abiotic stresses in B. rapa. In conclusion, our new developed 24K oligo microarray will be a useful tool for transcriptome profiling and this work will provide valuable insight in the response to abiotic stress in B. rapa.

GE 7FA+e DLN-2.6 가스터빈 연소기 연구 : Part Ⅰ 운전조건 최적화 (GE 7FA+e DLN-2.6 Gas Turbine Combustor : Part Ⅰ Operating Condition Optimization)

  • 오정석;김민기;허필원;이장수;윤영빈
    • 한국추진공학회지
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    • 제12권5호
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    • pp.43-50
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    • 2008
  • 서인천 복합 화력발전소의 GE 7FA+e DLN-2.6 가스터빈 연소기 튜닝을 실시하였다. DLN-2.6 연소기는 기동초기 저출력 조건에서 yellow plume 현상과 정상상태보다 높은 수준의 연소진동이 발생하는 문제점이 있었다. 본 논문의 목적은 기동초기의 yellow plume과 연소진동의 발생 원인을 규명하여 실 연소기를 안정적으로 운용할 수 있는 최적의 운전 조건을 제시하는 것이다. 실연소기 튜닝과정을 통해 얻은 자료를 분석한 결과 기동초기 모드 3($20{\sim}30MW$)에서 PM 1 노즐에서의 과농한 혼합기(${\phi}{\sim}1$)에 의해 yellow plume이 생성되었다. 모드 6B($40{\sim}45MW$)에서의 연소진동 발생은 $120{\sim}140Hz$ 부근에서 생성되었고 연소기 온도에 영향을 받지 않는 cold flow 특성으로 보이며 PM 3 노즐에서의 유량과 관련이 있었다.

GE 7FA+e DLN-2.6 가스터빈 연소기 연구 : Part II 모형 덤프 연소기 설계 (GE 7FA+e DLN-2.6 Gas Turbine Combustor : Part II Design of Lab Scale Dump Combustor)

  • 오정석;김민기;허필원;이장수;윤영빈
    • 한국추진공학회지
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    • 제12권5호
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    • pp.51-59
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    • 2008
  • 한국서부발전(주) 산하 서인천 복합 화력발전소에서 운용중인 GE 7FA+e 가스터빈 DLN-2.6 연소기는 기동초기 연소진동과 yellow plume 현상이 발생하고 있는데 이러한 특성을 분석하고 모형 덤프 연소기 설계에 반영하기 위한 상사인자 고찰이 본 연구의 목적이다. 실연소기 분석을 통하여 $120{\sim}140Hz$에서 일어나는 연소진동은 cold flow에서 덤프 모드로 발생되었으며 이것의 모사를 위해 노즐 출구 이전의 빈 공간인 plenum을 설계하였다. 또한 주요 상사인자로 노즐의 회전수, 연료-공기 혼합거리, 노즐과 덤프면의 면적비, 노즐출구에서의 속도와 당량비, 연료 조성성분 등이 있다.

냉동 물류 창고 내 도크시스템을 통한 에너지 손실량 분석 (Analysis of Amount of Energy Loss for a Dock System in the Cold Distribution Center)

  • 양성준;김영주;허준;김태성
    • 설비공학논문집
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    • 제29권8호
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    • pp.419-428
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    • 2017
  • In this study, energy loss due to ventilation load in the dock system was analyzed through simulation. Also, flow generated in the dock system of the warehouse was measured using manufactured measuring devices. Numerical simulation was conducted by simulating the most common picking tasks by examining the actual working environment. Incompressible and unsteady turbulent flows were assumed, and the turbulence model was the k-e standard model. Proper grid was selected through grid dependency test. Measurement was conducted using Honeywell and Vaisala sensors, and flow and temperature inside the warehouse were measured and compared with simulation results to validate simulation. When comparing amount of loss occurring in two hours and amount of loss occurring in 15 minutes, docking time of the former was eight times longer but energy loss was 3.8 times lower. Ventilation load occurring during the initial period after opening docking system accounted for a large proportion of total ventilation load. Also, comparing the load when the dock was closed and the load when the truck was parked, ventilation load was significantly higher than load due to heat conduction from the wall. Therefore, in improving the docking system, it is effective to reduce the gap by improving compatibility of the docking system and truck, rather than wall material.

Al-4.0%Zn-1.5%Mg-0.9%Cu 합금의 압출, 압연 및 열처리에 따른 미세조직 변화 (Evolution of Microstructure in Al-4.0%Zn-1.5%Mg-0.9%Cu Alloy by Extrusion, Rolling and Heat Treatment)

  • 권혁곤;박종문;오명훈;박노진
    • 열처리공학회지
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    • 제31권2호
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    • pp.41-48
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    • 2018
  • In this study, microstructural changes due to extrusion, rolling and heat treatment were studied to fabricate Al-4.0wt%Zn-1.5wt%Mg-0.9wt%Cu alloys with homogeneous microstructure suitable for metal cases of smart phones and electronic products fabricated through plastic working. After extrusion microstructure and texture were developed very differently on the surface and inside. Inside, coarse grains were formed and a strong Cube component orientation was developed. On the surface, a weak texture was developed with small grains. After 72% cold rolling the intensity of the Cube component orientation was lower, and uniform texture was developed in all the layers and the R-value was uniformly predicted. After recrystallization, the grain size difference between at the surface and the inside is smaller, when 72% rolling was performed, indicating that a uniform structure is formed. Texture develops almost randomly after recrystallization and exhibits uniform R-values at all layers.