• 설비공학논문집
• /
• 제27권2호
• /
• pp.81-86
• /
• 2015

Performance of freezing and refrigeration systems in supermarket, which utilized $CO_2$ as a refrigerant, was investigated by using the Pack Calculation II. The configuration of simulated systems was basic parallel refrigeration system, cascade system, and two-stage system. The $CO_2$ cascade system showed higher COP than basic parallel R404A system by 13% for MT and 62% for LT, respectively. Among the $CO_2$ cascade systems, R717(MT)-$CO_2$(LT) showed the highest performance. Open-type intercooler method showed higher performance than liquid injection for the two-stage $CO_2$ systems.

• 한국결정성장학회:학술대회논문집
• /
• 한국결정성장학회 1998년도 PROCEEDINGS OF THE 15TH KACG TECHNICAL MEETING-PACIFIC RIM 3 SATELLITE SYMPOSIUM SESSION 4, HOTEL HYUNDAI, KYONGJU, SEPTEMBER 20-23, 1998
• /
• pp.9-13
• /
• 1998

Large vacuum Bridgman-Stockbarger (BS) equipments was composed for growing large diameter CaF2 crystals. The CaF2 crystal of 4.5-inch was grown under the conditions of freezing temperature gradient of 12$^{\circ}C$/cm and growing rate of 3mm/hr. Also the 6-inch crystal was grown by using thermal stabilization method under freezing temperature gradient of 14$^{\circ}C$/cm and growing rate of 2mm/hr. The dislocation density was characterized for evaluating the quality of crystals. And the optical properties such as transmittance, refractive index and fluorescence were analyzed in order to investigate on the applications of optical components.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
• /
• pp.197-200
• /
• 2004

The increase of the use of recycled aggregate is necessary for the decrease of building waste, but it is not possible to use concrete because of the various range of quality. Therefore, the quality grade and application method of recycled aggregate should be prescribed before the site application so in that this study we investigated the effect of the quality of recycled aggregate on the compressive strength, resistance freezing and thawing. As results of this study, the compressive strength of recycled aggregate concrete used recycled aggregate, as if it had high quality recycled aggregate is similar or higher to that of crushed stone. Also, this high quality recycled aggregate affect the increase of resistance freezing and thawing.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2001년도 학술논문발표회
• /
• pp.22-27
• /
• 2001

The purpose of this study is development of dry floor tile method that practically used for improving wet method's defect, with resin mat design. PE resin used mat which satisfied with bonding test, waterproof test, resistance to chemical attack test, resistance to impact test and freezing and thawing test is confirmed the basic property.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2000년도 춘계 학술대회지
• /
• pp.88-89
• /
• 2000

• 한국세라믹학회:학술대회논문집
• /
• 한국세라믹학회 2000년도 춘계총회,특별강연,심포지움,연구발표회
• /
• pp.50.1-50.1
• /
• 2000

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
• /
• pp.283-286
• /
• 1995

Due to finite bandwidth of missile dynamics, guidance commands in PN guidance tend to diverage as the missile approaches to the target. In this paper, a new method based on the short-time stability theorem is introduced to extend the stability region.

• 대한의용생체공학회:의공학회지
• /
• 제34권4호
• /
• pp.182-188
• /
• 2013

This study aims to develop a practical algorithm which can detect freezing of gait(FOG) in patients with Parkinson's disease(PD). Eighteen PD patients($68.8{\pm}11.1yrs.$) participated in this study, and three($68.7{\pm}4.0yrs.$) of them showed FOG. We suggested two time-domain algorithms(with 1-axis or 3-axes acceleration signals) and compared them with the frequency-domain algorithm in the literature. We measured the acceleration of left foot with a 3-axis accelerometer inserted at the insole of a shoe. In the time-domain method, the root-mean-square(RMS) acceleration was calculated in a moving window of 4s and FOG was defined as the periods during which RMS accelerations located within FOG range. The parameters in each algorithm were optimized for each subject using the simulated annealing method. The sensitivity and specificity were same, i.e., $89{\pm}8%$ for the time-domain method with 1-axis acceleration and were $91{\pm}7%$ and $90{\pm}8%$ for the time-domain method with 3-axes acceleration, respectively. Both performances were better in the time-domain methods than in the frequency-domain method although the results were statistically insignificant. The amount of calculation in the time-domain method was much smaller than in the frequency-domain method. Therefore it is expected that the suggested time domain algorithm would be advantageous in the systematic implementation of FOG detection.

• 한국수정란이식학회지
• /
• 제29권3호
• /
• pp.235-240
• /
• 2014

생쥐 2세포기, 4세포기, 8세포기를 각 발생 단계에서 채취하여 동결 보호제를 첨가한 서로 다른 배양액에서 배양하고, 배아의 동결 보존 및 융해 시 급속 처리와 저속 처리 단계로 비교하여 이들 조건이 배아의 생존과 발현에 미치는 영향을 조사하여 다음의 결과를 얻었다. 동결 보호제로 처리하여 배양액을 달리한 경우, 급속 단계에서는 모든 배양액에서 비슷한 발생율을 보였고, 저속단계의 4세포기와 8세포기는 D-PBS에서 높은 발생율을 보였다(P<0.05, P<0.01). 배아의 발생 시기에 따른 동결 보존 후, 발생율은 2, 4, 8세포기로 넘어갈수록 발생율의 증가를 보여 8세포기에서 발생율이 가장 높았다(P<0.01). 동결 보호제의 처리단계에 따른 발생율은 2세포기의 급속 단계에서는 유사하였으나, 4세포기와 8세포기는 저속단계에서 높은 발생율을 보였으며(P<0.05), 특히 8세포기에서 가장 높았다(P<0.01).

• Journal of Microbiology
• /
• 제45권6호
• /
• pp.593-596
• /
• 2007

In this study, we describe the development of a simple and efficient method for cell lysis via the insertion of a bacteriophage lambda lysis gene cluster into the pET22b expression vector in the following order; the T7 promoter, a gene for a target protein intended for production, Sam7 and R. This insertion of R and Sam7 into pET22b exerted no detrimental effects on cellular growth or the production of a target protein. The induction of the T7 promoter did not in itself result in the autolysis of cells in culture but the harvested cells were readily broken by freezing and thawing. We compared the efficiency of the cell lysis technique by freezing and thawing to that observed with sonication, and determined that both methods completely disintegrated the cells and released proteins into the solution. With our modification of pET22b, the lysis of cells became quite simple, efficient, and reliable. This strategy may prove useful for a broad variety of applications, particularly in experiments requiring extensive cell breakage, including library screening and culture condition exploration, in addition to protein purification.