• 천문학회보
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• 제37권1호
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• pp.96.1-96.1
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• 2012

Various electromagnetic fluctuations are observed in the upstream of Earth's bow shock. Properties of plasmas are important in determining the development of the fluctuations. In this study we analyze the phase space distribution functions of plasmas measured by the Cluster spacecraft to understand how the fluctuations develop. Plasmas in the upstream of Earth's bow shock often consist of multiple components, especially when the fluctuations exist. In addition to the solar wind beams, backstreaming ion beams and diffuse ions are also often observed separately or simultaneously. The solar wind beams are not much perturbed even within the fluctuations. The diffuse ions are more than 10 times hotter than the solar wind beams and the backstreaming beams intermediate between them. The distribution functions of the diffuse and backstreaming ions are anisotropic to the magnetic field. Thus, they may be responsible for the fluctuations associated with temperature anisotropy. We will discuss about the thermalization processes and the relationship between the fluctuations and plasmas.

• International Journal of Industrial Entomology and Biomaterials
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• 제19권1호
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• pp.155-164
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• 2009

The most important factors in environment that influence the physiology of insects are temperature and humidity. Insects display a remarkable range of adaptations to changing environments and maintain their internal temperature (thermoregulation) and water content within tolerable limits, despite wide fluctuations in their surroundings. Adaptation is a complex and dynamic state that widely differs in species. Surviving under changing environment in insects depends on dispersal, habitat selection, habitat modification, relationship with ice and water, resistance to cold, diapause and developmental rate, sensitivity to environmental signals and syntheses of variety of cryoprotectant molecules. The mulberry silkworm (Bombyx mori) is very delicate and sensitive to environmental fluctuations and unable to survive naturally because of their domestication since ancient times. Thus, the adaptability to environmental conditions in the silkworm is quite different from those of wild insects. Temperature, humidity, air circulation, gases and photoperiod etc. shows a significant interaction in their effect on the physiology of silkworm depending upon the combination of factors and developmental stage affecting growth, development, productivity and quality of silk. An attempt has been made in this article to briefly discuss adaptation in insects with special emphasis on the role of environmental factors and their fluctuations and its significance in the physiology of mulberry silkworm, B. mori.

• 한국환경과학회지
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• 제18권2호
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• pp.141-151
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• 2009

Temperature, salinity, COD, DIN (Dissolved Inorganic Nitrogen), DIP (Dissolved Inorganic Phosphorus), and Chlorophyll ${\alpha}$ obtained from the southern coastal waters during the period of 2003 to 2005 were analyzed. Variability in temperature was not found between groups in southern coastal waters, but significantly different depending on sampling sites (p<0.05). The average temperature in 2003 estimated at $18.33^{\circ}C$ that was annually increased by 2005 and significantly different based on statistics (p<0.05). Unlikely to temperature, salinity was significantly different depending on sampling sites, as well as monthly variations (p<0.05). Likewise to temperature, the value of salinity was annually increased. COD estimated at the average of $>1.7\;mg\;l^{-1}$ for three years, indicating optimal water quality. The fluctuations of nutrients were extremely shown in different sampling sites and monthly variations. Chlorophyll a recorded above $2.0{\mu}g\;l^{-1}$ which was associated with high primary phytoplankton, whereas it showed much fluctuations in temporal and spatial, In particular, Tongyong, Jaranman, Jinjuman, and Samcheonpo located in the southeast were the highest fluctuations in water quality than any other regions. The correlation between salinity/COD and nutrients/chlorophyll a was strongly negative or positive, which was possibly associated with much the introduction of run-off water as well as rainfall in summer.

• Fisheries and Aquatic Sciences
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• 제10권3호
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• pp.150-158
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• 2007

Data on squid catches, water temperature, and climatic factors collected for the Northwest and subtropical North Pacific were analyzed to examine the influence of oceanic and climatic conditions in spawning grounds on catches of Japanese common squid, Todarodes pacificus, in the East (Japan) Sea. The main spawning ground was divided into four sub-areas: the South Sea of Korea (R1), the southern waters off Jeju, Korea (R2), the southwestern part of Kyushu, Japan (R3), and the northern part of Okinawa, Japan (R4). Interannual and decadal fluctuations in water temperatures correlated well with squid catches in the East/Japan Sea. In particular, water temperatures at a depth of 50 to 100 m in sub-areas R3 and R4 showed higher correlation coefficients (0.54 to 0.59, p<0.01) in relation to squid catches in the East/Japan Sea than for R1 and R2, which had correlation coefficients of 0.40 or less (p>0.05). Air temperature and wind velocity fluctuations in each sub-area are correlated with water temperature fluctuations and were closely connected with variations in the surface mixed layers. Water, air temperatures and wind velocities at the main spawning grounds are linked to the Southern Oscillation Index (SOI) with higher signals in the ca. 2-4-year band. Strong changes in a specific band and phase occurred around 1976/77 and 1986/87, coincident with changes in squid catches.

• 한국결정성장학회지
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• 제10권6호
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• pp.381-388
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• 2000

Czochralski 결정 성장 시스템에서 baroclinic 불안정성에 의해 발생하는 유동과 온도 변동에 대해 실험적으로 고찰하였다. 실리콘과 유사한 프란틀 수를 갖는 Wood's metal을 작동유체로 사용하고, 일체형 자석 프로브를 제작하여 멜트의 회전 유속을 측정하였다. 측정 결과 회전 유속은 멜트 바닥에 비해 자유 표면에서 빠르고 특히 결정 근처에서 유속이 증가하는 것을 확인하였다. 또한 도가니 회전 속도를 증가시키면서 속도와 온도 변동을 관찰한 결과 Ro<1.01, Ta>$9.63{\times}10^8$인 영역에서 baroclinic 불안정성이 나타나고, 이 영역에서 유동과 온도가 동일한 주파수를 가지고 변동하였다.

• 한국환경과학회지
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• 제25권2호
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• pp.295-310
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• 2016

In this study, changes in daily temperature range were investigated using daily maximum and minimum temperatures of Busan and Daegu for last 81 years (1934-2014), and also characteristics of daily temperature range and seasonal fluctuations by urbanization were examined. First, elapsing changes showed a lower decreasing trend in Busan ($0.32^{\circ}C$) than Daegu ($1.28^{\circ}C$) for last 81 years. Daily temperature range showed the highest rise in winter in both Busan and Daegu. Second, daily temperature range due to urbanization showed that Busan had a pronounced decreasing trend before urbanization meanwhile Daegu showed the same trend after urbanization. On seasonal changes, the results of Busan showed a decreasing trend in summer before urbanization, and in autumn after urbanization. For Daegu, the results showed a decreasing trend in spring before urbanization, and in winter after urbanization. Seasonal fluctuations of Busan showed little difference in the pre and post-urbanization, except in winter and summer. There was large difference in daily temperature range in winter after urbanization, and in summer before the urbanization. The results in Daegu showed that there was decreasing trend of daily temperature range in all seasons after urbanization.

• 한국식품과학회지
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• 제25권6호
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• pp.643-648
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• 1993

표준온도 상당시간을 이용하여 규칙적인 온도변화 조건에서 식품의 품질변화를 간편하게 예측하는 근사식의 유효성을 밝히기 위하여, 비등온 가속조건 및 상온저장 조건에서 Sucrose 가수분해속도를 측정한 설험자료로 비교, 분석을 분석하였다. 정속가열 (定速加熱) 가속(加速)실험을 통해 구한 sucrose의 가수분해 반응은 1차 반응이고, 활성화에너지는 25.84kcal/mol이었으며, 반응속도상수는 pH가 감소함에 따라 직선적으로 증가하였다. 하루 동안의 온도변화를 sine wave 형태 온도변화로 가정하고 하루 동안에 일어난 품질변화를 표준온도 $T_{ref}$에서 몇일 동안에 일어난 변화에 상당하는가를 의미하는 표준온도 상당시간 $T_{eq.i}$를 이용하여 품질변화를 근사적으로 간단히 예측하는 방법을 제안하였다. Sucrose 액체 모델 시스템을 sine wave 형태의 규칙적인 온도변화 조건에서의 가속 가수분해실험 결과와 $T_{eq.i}$를 이용하여 품질변화를 computer simulation한 결과, 실험값과 예측값과의 상관계수는 0.99로서 잘 일치하였으므로 표준온도상당시간을 이용한 예측 모델의 유효함을 확인하였다. 뿐만 아니라 sucrose 모델 시스템을 실제 상온 저장한 실험결과와 계절적 온도변화를 computer simulation하여 예측한 값과는 상관계수가 0.92로서 잘 일치하였다.

• 수산해양기술연구
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• 제56권4호
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• pp.322-339
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• 2020

Temporal and spatial fluctuations of surface water temperature in Yeosu Bay for the period from 2010 to 2011 were studied using the data from temperature monitoring buoys deployed at 32 stations in the south coast of Korea. Temperatures in the northern part of the bay are higher in summer and lower in winter than in the southern part of the bay. The lowest and highest temperature of the annual mean are found at the eastern coast of POSCO and at the west of Dae Island, respectively. Cold water masses appear at estuarine area when the discharge of Sumjin river is affluent. Amplitude of temperature fluctuation whose period is less than semi-diurnal is largest at Hadong coast and around Dae Island. Spectral analysis of surface water temperature shows a significant peak at a periodic fluctuation of 0.5 to 24 days and about 15-day period of predominant fluctuation is most frequent in Yeosu Bay. From the cross-correlation analysis of temperature fluctuations, Yeosu Bay can be classified into six areas; the south area affected by South Sea of Korea, the mixed area in the center of the bay, the estuarine area affected by river discharge at the north of the bay, the hot waste water area near Hadong coast, the area around Dae Island and the area near Noryang Channel affected by the water in Jinju Bay, respectively.

• Korean Chemical Engineering Research
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• 제46권4호
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• pp.707-713
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• 2008

직경이 0.102 m이고 높이가 2.0 m인 annular 유동층에서 최소유동화 속도 및 압력 요동 특성을 고찰하였다. 기체유속($U_G$), 고체 입자의 크기($d_p$) 그리고 유동층 온도가 최소유동화 속도 및 압력 요동 특성에 미치는 영향을 검토하였다. 본 연구 결과, annular 유동층 내의 압력 요동 자료로부터 구한 상관차원을 유동층 내부의 기체 및 유동 입자의 복합적인 거동을 정량적으로 나타내는 파라미터로 쓸 수 있었으며, 이 상관차원의 값은 기체의 유속, 유동 입자의 크기 그리고 반응기의 온도가 증가함에 따라 증가하였다. 유동층에서 유동입자의 최소유동화 속도를 유동층에서 압력 강하 및 압력 요동자료의 표준 편차를 사용하는 방법뿐만 아니라 압력 요동 자료의 상관차원을 이용하여서도 구할 수 있었으며 이들 각기 다른 방법으로 구한 최소 유동화 속도 값은 서로 매우 유사하였다. Annular 유동층에서 유동 입자의 최소유동화 속도는 유동 입자의 크기가 증가할수록 증가하였으나 유동층의 온도가 증가함에 따라 감소하였다. 본 연구의 범위내에서 annular 유동층에서 최소 유동화 속도를 압력 요동 자료의 상관 차원과 무차원군의 함수로 나타낼 수 있었다.

• 천문학회보
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• 제26권2호
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• pp.32.1-32.1
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• 2001