• Journal of the Korean Magnetics Society
• /
• v.14 no.5
• /
• pp.169-173
• /
• 2004

We have synthesized monodispersed $\alpha$-F $e_2$ $O_3$ nano particles to investigate the spin change during the Morin transition temperature( $T_{M}$). The particle size was founded to have a very uniform distribution of 80 nm by x-ray diffraction and size dispersion analyzer. The Mossbauer spectra between the 4.2 K and the room temperature show that $T_{M}$ was shifted and the spin states of Fe ion were changed with the particle size. The Morin transition temperature of bulk usually quoted in literature is 265 K but, it decreases with the size and no transition was found at the critical size down to 4.2K. The spin direction of 80 nm sized particles are normal to the hexagonal c-axis above the $T_{M}$ and are tilted about 28～29$^{\circ}$ below $T_{M}$, which is the [110] direction of rombohedral structure.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2017.10a
• /
• pp.189-189
• /
• 2017

• 프린팅코리아
• /
• v.14 no.3
• /
• pp.120-123
• /
• 2014

디지털 기술의 발전은 커뮤니케이션과 그래픽 산업의 지속적인 변화를 요구하고 있다. 물론 이에 대응하려는 인쇄인의 노력도 전 세계적으로 끊임없이 이어지고 있다. 약간의 온도차는 있지만, 변화하는 패러다임 변화에 부응하려는 미국의 사례를 살펴봄으로써 우리의 대응방안을 가늠해 본다.

• 프린팅코리아
• /
• s.15
• /
• pp.72-73
• /
• 2003

인류는 오래 전부터 불씨를 얻는 방법으로 단단한 나무끼리의 마찰 또는 돌끼리 맞부딪치게하여 불을 일으켜서 사용하여 왔다. 성냥을 만들어 사용하게 된것은 그리 오래되지는 않는다. 1669년에 낮은 온도에서 타는 인이 발견되어 근대적인 성냥을 만드는 길이 열리게 되었다.

• Electric Engineers Magazine
• /
• v.205 no.9
• /
• pp.32-36
• /
• 1999

전동기에 있어서 단자전압의 불평형은 전동기에 역상전류를 흐르게 한다. 전동기의 온도상승에 영향을 주는 것은 이 역상전류이다.

• Proceedings of the KSR Conference
• /
• 2006.05b
• /
• pp.1162-1166
• /
• 2006

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2020.10a
• /
• pp.134-134
• /
• 2020

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.22 no.3
• /
• pp.143-154
• /
• 2016

The purpose of this study was investigated the quality changes before and after harvesting, storage and, processing of onion. Experiments were carried out to compare the effect on the characteristics of the postharvest from preharvest factors using onion. This experiment had identified the characteristics of harvested onions after cultivating with several preharvest factors such as the light and water conditions. These tests were conducted in an onion growth in the field, storage, and processing of fresh-cut during a laboratory periods of 2 years. In first year, onion cultivars ('Kars' and 'Pop') were produced under stable or unstable environment conditions, these onions were stored at low temperature(0?). Measurement was evaluated by the growth amount after harvesting, and the fresh weight loss and respiration rate during storage. According to different culture conditions and storage temperatures, it was investigated the properties of the fresh-cut onion. Growth of onion was varied depending on the cultivars and culture conditions. The amount of growth on 'Kars' and 'Pop' onions were decreased by excessive soil water conditions with shading. These influences were found the morphological differences resulting for the cell tissue of onion being rough and large. Onion cultivated in excessive soil water with shading affected the degree of its respiration rate and fresh weight loss during storage. Ones in excessive soil water with shading were higher than the control in fresh weight loss and respiration rate, respectively. However fresh-cut onion could not investigated to clarify the difference due to effects of cultivation condition and storage temperature on some measure items such as electrolyte leakage and microbial number change. There was a change of only electrolyte leakage depending on the storage temperature, rather than cultivated conditions before harvesting factor. The results showed that the onion grown on in the good environment was represented to a good quality produce even after harvesting.

• Korean Journal of Optics and Photonics
• /
• v.13 no.3
• /
• pp.240-244
• /
• 2002

We proposed a novel temperature sensor based on the phenomena that the phase difference between principal polarization states in an optical retarder is a function of temperature. The polarization state of an optical beam is changed as it passes through the optical retarder, with the change dependent on the temperature. The temperature of the optical retarder is determined by comparison of the power difference between principal polarization states. A temperature sensor was successfully implemented using a polarization maintaining fiber of length 100 mm as the optical retarder. The change rate of phase difference on temperature was 0.236$^{\circ}C$$_{-1}$ and the measurement error was $\pm$0.038$^{\circ}C$ over the temperature region of -2.6$^{\circ}C$~3.4$^{\circ}C$.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.405-405
• /
• 2012

InSb는 높은 전자이동도와 낮은 밴드갭을 가지고 있어 저전력 고효율의 고주파소자 및 비선형 광소자에 적합한 물질이다. 특히 InSb 기반 소자들은 전자-포논효과의 영향을 덜 받는 저온에서 고감도 소자로도 사용되고 있는데, 소자의 최적합 설계와 제작시의 실시간 성장제어를 위해서는 넓은 온도범위에서의 InSb의 광물성이 필요하다. 분광타원편광분석법(ellipsometry)은 물질의 광특성인 유전율 함수를 정확하게 측정 할 수 있은 기술로써, InSb 에 대한 유전율 함수는 많은 연구를 통해 잘 알려져 있다. 그러나, 온도변화에 대한 연구로는 100-700 K, 1.2-5.6 eV의 제한된 온도와 분광영역에서만 이루어졌다. 본 연구에서는 보다 확장된 온도범위(25-686 K), 광역 에너지 범위 (0.74-6.5 eV)에서 분광타원편광분석 연구를 수행하였다. 그 결과 저온에서의 전자-포논 효과의 감소로 인한 청색천이와 보다 명확한 전자전이점들의 값을 얻었다. 특히, 100 K 까지의 이전 연구에서는 구분할 수 없었던 $E_2'$ 전이점을 본 연구의 25 K 의 유전율 함수에서 명확히 구분할 수 있었고, 고에너지 영역의 $E_1'+{\Delta}_1+{\Delta}_1'$ 전이점의 온도의존성을 처음으로 연구하였다. 본 연구의 결과는 InSb 를 기반으로 한 광전자 소자의 개발 및 적용분야와 밴드갭 엔지니어링 분야에 많은 도움이 될 것으로 예상한다.