• 제목/요약/키워드: Cold Chamber

검색결과 278건 처리시간 0.026초

남녀 대학생의 겨울철 실내 쾌적온도 및 적정온도 (Preferred and Suggested Winter Indoor Temperatures of College Students)

  • 심현섭;정운선
    • 한국지역사회생활과학회지
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    • 제22권3호
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    • pp.485-491
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    • 2011
  • This study was to present the preferred and the suggested indoor temperature of college students in winter based on their body composition. A total of 14 subjects(6 males and 8 females) participated in this study. They sat in a climatic chamber controlled at $24^{\circ}C$ wearing experimental garments(0.7clo). The air temperature decreased $1^{\circ}C$ every 15 minutes until it reached $19^{\circ}C$. After the stepwise temperature change, subjects were asked to select a comfortable air temperature by dialing the temperature control switch inside the chamber. The preferred temperature was determined when subjects did not change the air temperature for 10 minutes. The measurements were oxygen consumption, rectal temperature, skin temperature, and subjective sensation. Main results are as follows. In a mild cold condition, females demonstrated lower oxygen consumption and mean skin temperature than males while keeping a constant rectal temperature. Females increased rectal temperature and decreased mean skin temperature greater than males from $24^{\circ}C$ to $19^{\circ}C$. Males showed larger oxygen consumption increase than females. It appears that the thermo-physiological responses in a mild cold condition might be different between males and females. The preferred winter indoor temperature was $22.3^{\circ}C$ for males and $23.4^{\circ}C$ for females, and the suggested temperature was $21^{\circ}C$ for males and $23^{\circ}C$ for females.

STUDY OF CORRELATION BETWEEN WETTED FUEL FOOTPRINTS ON COMBUSTION CHAMBER WALLS AND UBHC IN ENGINE START PROCESSES

  • KIM H.;YOON S.;LAI M.-C.
    • International Journal of Automotive Technology
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    • 제6권5호
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    • pp.437-444
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    • 2005
  • Unburned hydrocarbon (UBHC) emissions from gasoline engines remain a primary engineering research and development concern due to stricter emission regulations. Gasoline engines produce more UBHC emissions during cold start and warm-up than during any other stage of operation, because of insufficient fuel-air mixing, particularly in view of the additional fuel enrichment used for early starting. Impingement of fuel droplets on the cylinder wall is a major source of UBHC and a concern for oil dilution. This paper describes an experimental study that was carried out to investigate the distribution and 'footprint' of fuel droplets impinging on the cylinder wall during the intake stroke under engine starting conditions. Injectors having different targeting and atomization characteristics were used in a 4-Valve engine with optical access to the intake port and combustion chamber. The spray and targeting performance were characterized using high-speed visualization and Phase Doppler Interferometry techniques. The fuel droplets impinging on the port, cylinder wall and piston top were characterized using a color imaging technique during simulated engine start-up from room temperature. Highly absorbent filter paper was placed around the circumference of the cylinder liner and on the piston top to collect fuel droplets during the intake strokes. A small amount of colored dye, which dissolves completely in gasoline, was used as the tracer. Color density on the paper, which is correlated with the amount of fuel deposited and its distribution on the cylinder wall, was measured using image analysis. The results show that by comparing the locations of the wetted footprints and their color intensities, the influence of fuel injection and engine conditions can be qualitatively and quantitatively examined. Fast FID measurements of UBHC were also performed on the engine for correlation to the mixture formation results.

"금궤요략.부인산후맥증병치제이십일(婦人産後脈證幷治第二十一)"에 대(對)한 연구(硏究) (A Study on the "Diagnosis and Treatment of the Postpartum Syndromes[婦人産後脈證幷治]" in "Synopsis of Golden Chamber)

  • 이윤천;고승욱;박금숙;정헌영;금경수
    • 대한한의학원전학회지
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    • 제21권1호
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    • pp.43-62
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    • 2008
  • After parturition, woman in childbed's health can grow worse. Because when woman in childbed gives birth, Genital organ can be damaged, and lost a lot of blood, and also consume a lot of physical strengths. So, after parturition, woman in childbed is easy to fall in disease if do not take care in health specially. So after parturition, woman in childbed should be careful in stress, sleep, food etc. This thesis described Postpartum Spasm[痙病], Oppressive Feeling and Dizziness[鬱冒], Constipation[便秘], Abdominal Pain[腹痛], Diarrhea[下利], Annoyance[煩亂] and Vomitting Sickness[嘔逆]. Postpartum Spasm[痙病]'s major symptom is rigided body. This disease corresponds to Tetanus in modem medicine, and bacterial infection is assumed for cause. By Oriental medicine, after parturition, when blood is lacking, if patient takes wind, this disease breaks out. Oppressive Feeling and Dizziness[鬱冒]'s major symptom is dizzy head and gloomy eye. After parturition, when blood is lacking, if patient sweats too much and take cold, this disease breaks out. After parturition, if patient consumes a lot of resins of human body, Constipation[使秘] breaks out. There are four causes to Abdominal pain[腹痛]. First, due to deficiency and cold treats by Danggwisaenggangyangyuktang(當歸牛薑羊肉湯). Second, due to stagnation of Gi(氣) treats by Jisiljakyaksan(枳實芍藥散). Third, due to blood stasis treats by Ha-eohyeoltang(下瘀血湯). Fourth, due to lochiorrhea treats by Daeseunggitang(大承氣湯). After parturition, Annoyance[煩亂] and Vomitting Sickness[嘔逆] due to fever of difficiency treat by Jukpidaehwan(竹皮大丸). After parturition, Febrile diarrhea[熱性下利] treats by Baekduonggagamchoagyotang(白頭翁加甘草阿膠湯). This disease is similar with present Bacillary Dysentery. After parturition, Exteroceptive disease due to taking wind treats by Yangdaltang. Due to wind and fever treats by Jukyeoptang(竹葉湯).

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Effects of a compaction method for powder compacts on the critical current density of MgB2 bulk superconductors

  • Kang, M.O.;Joo, J.;Jun, B.H.;Choo, K.N.;Kim, C.J.
    • 한국초전도ㆍ저온공학회논문지
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    • 제21권2호
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    • pp.40-44
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    • 2019
  • In this study, the effects of the compaction method for (Mg+2B) powders on the apparent density and superconducting properties of $MgB_2$ bulk superconductor were investigated. The raw powders used in this study were nano-sized boron (B) and spherical magnesium (Mg). A batch of a powder mixture of (Mg+2B) was put in a steel mold and uniaxially pressed at 1 ton or 3 tons into pellets. Another batch of the powder mixture was uniaxially pressed at 1 ton and then pressed isostatically at $1800kg/cm^2$ in the water chamber. All pellets were heat-treated at $650^{\circ}C$ for 1 h in flowing argon gas for the formation of $MgB_2$. The apparent density of powder compacts pressed at 3 ton was higher than that at 1 ton. The cold isostatic pressing (CIP) in a water chamber allowed further increase of the apparent density of powder compacts, which influenced the pellet density of the final products ($MgB_2$). The compaction methods (uniaxial pressing and CIP) did not affect the formation of $MgB_2$ and superconducting critical temperature ($T_c$) of $MgB_2$, but affected the critical current density ($J_c$) of $MgB_2$ significantly. The sample with the high apparent density showed high $J_c$ at 5 K and 20 K at applied magnetic fields (0-5 T).

처리조건에 따른 조생온주밀감의 저온저장 특성 (Cold Storage Characteristics of Early Variety of Citrus unshiu Produced in Cheju with Various Treatments)

  • 양영택;송상철;김성학;김지용;고정삼
    • Applied Biological Chemistry
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    • 제40권2호
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    • pp.117-122
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    • 1997
  • 제주산 궁천조생의 저장조건에 따른 저온저장 특성을 검토하였다. 상온저장에 비해 저온저장 감귤은 저장기간 중 가용성 고형물, 총당, 비타민 C의 변화가 매우 적었으며, 부패율과 중량감소가 각각 10% 이내 수준에서 비교적 신선도를 유지한 상태에서 3월 하순까지 저장이 가능한 것으로 보였다. 또한, 중량감소, 경도의 저하, 당함량의 감소는 저장기간 중에 계속하여 서서히 일어났다. 필름포장과 wax-coating은 중량감소와 외관향상에는 도움을 주었으나 장기간 저장에는 부패율이 증가하였다. 습도조절을 하지 않은 저온저장은 습도조절한 경우와 비교하였을 때 부패율과 중량감소가 컸다. 증산작용으로 인한 껍질수분의 감소에 따라 과육으로부터 수분이동이 발생하여 저장기간 중 과육율이 감소하였으며, 저장 60일 후부터 경도저하가 많이 일어나 조직이 연화됨을 알 수 있었다. 조기수확한 감귤에 비하여 완숙한 감귤이 부패율과 중량감소가 적어 저장 100일간을 기준하여 출하하는 것이 바람직하였다. 상온저장한 감귤에 비해 저온저장한 감귤은 저장 4개월 이후 출고하였을 경우 외관 및 맛에 비교적 우수하였으며, 출고후 필름포장한 감귤의 부패율은 급속히 증가하여 취급에 주의가 필요하였다. 조생온주의 경우 저온에서 장기간 저장이 어려움을 알 수 있어서 저장용 감귤의 특성을 고려하여 저장조건을 설정할 필요가 있었다.

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환경온도 -10℃에서 Clo값에 따른 인체 생리반응 및 주관적 감각 (Physiological Responses and Subjective Sensations by Clo Values at -10℃)

  • 김지연;송민규;김희은
    • 한국의류산업학회지
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    • 제12권4호
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    • pp.531-537
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    • 2010
  • The purpose of this study was to review physiological responses and subjective sensations in the cold environment when the subjects wore ensemble with different clo values. Seven healthy male subjects participated in this experiment. This experiment was conducted in a climatic chamber with $-10^sC$ and 50%RH. Subjects wore five different kinds of ensemble[C1 (4.453 clo), C2 (3.452 clo), C3 (2.865 clo), C4 (2.387 clo), and C5 (2.280 clo)]. The experiment was composed of 20 min of rest period, 20min of treadmill exercise(6 km/h) period, 30 min of recovery period. We monitored skin temperature on 7 sites, clothing microclimate and subjective sensations. The clo value had positive correlations with mean skin temperature and clothing microclimate. The subjects feel more warm and humid as the clo value goes up. The subjects reported comfort when they wore C1 and C2 ensemble having over 3 clo value. However, they felt less comfortable during the exercise period since there was high humidity. Skin temperature on the extremities were more dramatically changed by the exercise rather than clo value. Thus it seems that in the cold environment, heat balance can mostly be controlled by the choice of clothing, and the clothes with high clo values can provide higher insulation. In conclusion, our findings suggest that it would be more effective to control clo value depending on the activity level for maintaining comfort level in the cold environment.

1-Methylcyclopropene(1-MCP) 처리가 오이의 신선도 유지에 미치는 영향 (Effect of 1-Methylcyclopropene(1-MCP) on the Postharvest Life and Fruit Quality of Cucumber)

  • 양용준
    • 한국산학기술학회논문지
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    • 제9권6호
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    • pp.1882-1888
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    • 2008
  • 1-MCP(1-methylcyclopropene) 처리에 의한 오이 'Baekdadaki'의 수확 후 품질에 관한 연구를 수행하였다. 1-MCP의 농도별 250ppb, 500ppb, 1,000ppb 처리 후 상온과 저온($10^{\circ}C$)으로 나누어 저장하면서 생리적 특성변화 및 호흡율, 에틸렌 발생율을 조사하였다. 물리화학적 특성변화로 생체중과 경도는 상온, 저온 모두 저장 중 감소하였고 1-MCP 처리중에는 저온의 500ppb 에서 가장 적은 감소율을 보였다. 노화의 지표인 과피 b값은 상온괴 저온 모두 1-MCP 250, 1,000ppb에서 가장 높은 증가율을 보였고 저온저장 15일째에 황화와 함께 과실 무름 현상이 나타났다. 오이의 저온저장 15일 동안 1-MCP 500ppb 처리에서 가장 낮은 부패율을 나타내어 상품성을 상대적으로 높게 유지하였다. 호흡율은 1-MCP 250ppb 처리에서 높은 증가율을 보였고, 에틸렌 발생량은 상온 저장된 1,000ppb 에서 저장 6일 동안 가장 높은 증가율을 보였다. 오이 'Baekdadaki' 품종의 수확 후 품질은 1-MCP 500ppb 농도에서 가장 좋은 품질을 유지하였고 여러 농도의 1-MCP 처리에서 에틸렌 생성이 억제되지는 않았다.

Suggested and Preferred Amount of Clothing in a Winter Indoor Condition

  • Shim, Huen-Sup;Jeong, Woon-Seon
    • 한국의류학회지
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    • 제35권12호
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    • pp.1418-1424
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    • 2011
  • This study proposes the suggested amount of clothing (SAC) and examines the preferred amount of clothing (PAC) for thermal comfort in mild cold conditions. Six male and nine female college students were systematically exposed to mild cold conditions by reducing the amount of clothing (Step I, 1.2clo ${\rightarrow}$ Step II, 1.0clo ${\rightarrow}$ Step III, 0.8clo ${\rightarrow}$ Step IV, 0.7clo). The subjects were then asked to adjust the amount of clothing to attain overall thermal comfort until they maintained thermal comfort for 10 minutes without changing the amount of clothing (Step V). The experiment was carried out in a climatic chamber at $19.5^{\circ}C$, 50%R.H. Body composition was measured and individual cold climate adaptability was surveyed before starting the experiment. Rectal temperature ($T^{re}$), skin temperature ($T_{sk}$), and oxygen consumption ($\dot{V}O_2$) were measured and the overall thermal sensation was voted in each step. PAC was obtained from the garments weight selected by each subject in Step V. SAC was proposed based on the change of oxygen consumption (${\Delta}\dot{V}O_2$). As a result, males showed higher $\bar{T}_{sk}$ and greater $O_2$ than females (p<.01). SAC obtained from $\dot{V}O_2$ were 652.0 (SE 3.9) g/$m^2$ for males and 766.0 (SE 2.5) g/$m^2$ for females and it was significantly different between groups (p<.01). PAC of males and females were 1.6 and 1.5 times heavier than SAC. In conclusion, females were more sensitive to the cold stress and recommended larger amount of clothing than males.

고령 남자의 겨울철 모자 착용 효과 -생리·심리적 검토- (Physiological and Psychological Effects of Wearing Winter Cap in Elderly Males)

  • 박준희;이주영
    • 한국의류학회지
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    • 제43권3호
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    • pp.405-415
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    • 2019
  • This study examined the physiological and psychological effects of wearing a winter cap at rest in a cold environment. Seven older males participated in two separate trials: wearing a winter cap (CAP) and non-wearing a winter cap (CON). The experiment was conducted for 60 min in a climatic chamber (air temperature $7.8{\pm}0.3^{\circ}C$ with $43{\pm}2%RH$) with sedentary posture. Microclimate temperature at the vertex of the head was $6.88^{\circ}C$ higher in CAP compared to CON (p<.01). Microclimate humidity at the vertex was lower in CAP than in CON only during the last 5 min (p<.01). Skin temperature at the forehead in CAP was higher than in CON (p<.01). During the last 5 min, rectal temperature was higher in CAP than that in CON (p<.05). Unlike CAP, the heart rate in CON during the last 5 min decreased significantly compared to the initial 5 min (p<.05). Subjects also felt less cold on the head/face in CAP than that in CON (p<.01). The results indicate that wearing a cap for elderly males positively affected body temperature regulation and cardiovascular response in cold environments. The importance of wearing warm hats for elderly males in winter should be emphasized.

QTL Mapping of Cold Tolerance at the Seedling Stage using Introgression Lines Derived from an Intersubspecific Cross in Rice

  • Park, In-Kyu;Oh, Chang-Sik;Kim, Dong-Min;Yeo, Sang-Min;Ahn, Sang-Nag
    • Plant Breeding and Biotechnology
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    • 제1권1호
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    • pp.1-8
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    • 2013
  • Low-temperature stress is an important factor controlling the growth and development of rice (Oryza sativa L.) in temperate region. In this study, a molecular linkage map consisting of 136 SSR markers was employed to identify QTL associated with cold tolerance at the seedling stage. 80 recombinant inbred lines (RILs) from an intersubspecific cross between Milyang23 (O. sativa ssp. Indica) and Hapcheonaengmi3, a japonica weedy rice and the parents were evaluated for leaf discoloration and SAPD value of seedlings. Rice plants were grown for 15 days in the low-temperature condition (13/20℃ day/night) and the control condition (25/20℃ day/night) in the growth chamber. The degree of leaf discoloration showed a highly significant correlation with the SPAD value in the low-temperature plot (r = -0.708, P < 0.0001). A total of four QTLs for SPAD were identified and the phenotypic variance explained by each QTL ranged from 5.4 to 16.0%. Two QTLs detected in the control condition were located on chromosomes 2 and 5, respectively. Two QTL on chromosomes 1 and 4 were detected at the low-temperature condition and Hapcheonaengmi3 alleles increased the SPAD values at these loci. Substitution mapping was conducted to delimit the position of qSPA-4 using introgression lines derived from the same cross. Results indicated that qSPA-4 was located in a 810-Kb region flanked by RM16333 and RM16368. The results indicated that Hapcheonaengmi3 contains QTL alleles that are likely to improve cold tolerance of Indica rice.