• Journal of Microbiology and Biotechnology
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• 제33권8호
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• pp.1066-1075
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• 2023

Kimchi is a traditional Korean fermented vegetable that is stored and fermented at low temperatures. However, kimchi lactic acid bacteria (LAB) are typically isolated under mesophilic conditions, which may be inappropriate for isolating the diverse LAB. Therefore, this study investigated the suitable conditions for isolating various LAB from kimchi. Here, LAB were isolated from four kimchi samples using MRS, PES, and LBS media and varying isolation temperatures (30, 20, 10, and 5℃). Then, MRS was selected as the suitable medium for LAB isolation. A comparison of culture-dependent and culture-independent approaches indicated that 5℃ was not a suitable isolation temperature. Thus, the number and diversity of LAB were determined at 30, 20, and 10℃ using 12 additional kimchi samples to elucidate the effect of isolation temperature. With the exception of two samples, most samples did not substantially differ in LAB number. However, Leuconostoc gelidum, Leuconostoc gasicomitatum, Leuconostoc inhae, Dellaglioa algida, Companilactobacillus kimchiensis, Leuconostoc miyukkimchii, Leuconostoc holzapfelii, and Leuconostoc carnosum were isolated only at 10 and 20℃. The growth curves of these isolates, except Leu. holzapfelii and Leu. carnosum, showed poor growth at 30℃. This confirmed their psychrotrophic characteristics. In Weissella koreensis, which was isolated at all isolation temperatures, there was a difference in the fatty acid composition of membranes between strains that could grow well at 30℃ and those that could not. These findings can contribute to the isolation of more diverse psychrotrophic strains that were not well isolated under mesophilic temperatures.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2005년도 학술발표회 논문집
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• pp.497-504
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• 2005

This paper presents the results of experimental studies on the equipment isolation effect considering the floor response. For this purpose, shaking table tests were performed. For the measuring the floor response, numerical analysis was performed. For the isolation for the equipment, Natural Rubber Bearing(NRB), High Damping Rubber Bearing(HDRB) and Friction Pendulum System(FPS) were used. Finally, it is presented that the isolation systems used in this test can be adopted for the small equipment isolation. But the rubber bearing used in this study affected to the temperature change very sensitively.

• 한국식품영양과학회지
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• 제26권6호
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• pp.1028-1032
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• 1997

Low-temperature crystallization method silver nitrate-impregnated silicic acid column chromatography were applied for the isolation of pure $\alpha$-linolenic acid(ALA) from perilla seed oil. ALA or 78% in purity(HALA; yield, 83%) was obtained from the fatty acid mixture(ALA, 65.7%) derived from perilla oil by the low-temperature crystallization method, when the mixture was frozen at -8$0^{\circ}C$ for 210min. ALA over 90% in purity(yield, 71%) was also obtained from HALA ethyl esters(ALA, 78%) by the silver nitrate-impregnated silicic acid column(100cm$\times$10cm, i.d.) chromatography. In addition, the silver nitrate-impregnated silicic acid could be semipermanently used for isolation of ALA, because $Ag^{+}$ ion was not dissociated from the stationary phase.

• Structural Engineering and Mechanics
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• 제87권5호
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• pp.405-418
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• 2023

This study focused on the effectiveness of seismic isolation technique in case of a reinforced concrete structure with soft story defined as the stiffness irregularity between adjacent stories. In this context, a seismically isolated 3-story reinforced concrete structure was analyzed by gradually increasing the first story height (3.0, 4.5, and 6.0 m). The seismic isolation system of the structure is assumed to be composed of lead rubber bearings (LRB). In the analyses, isolators were modeled by both deteriorating (temperature-dependent analyses) and non-deteriorating (bounding analyses) hysteretic representations. The deterioration in strength of isolator is due to temperature rise in the lead core during cyclic motion. The ground motion pairs used in bi-directional nonlinear dynamic analyses were selected and scaled according to codified procedures. In the analyses, different isolation periods (Tiso) and characteristic strength to weight ratios (Q/W) were considered in order to determine the sensitivity of structural response to the isolator properties. Response quantities under consideration are floor accelerations, and interstory drift ratios. Analyses results are compared for both hysteretic representations of LRBs. Results are also used to assess the significance of the ratio between the horizontal stiffnesses of soft story and isolation system. It is revealed that seismic isolation is a viable method to reduce structural damage in structures with soft story.

• 한국지진공학회논문집
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• 제12권1호
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• pp.67-77
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• 2008

내진기술의 한 방안으로서 지진격리받침을 설치하여 지진력을 감소시키고, 지진피해를 최소화하고자 하는 연구가 계속되고 있다. 이와 같은 지진격리시스템의 설계 및 시공을 위해서는 먼저 지진격리받침의 제작시 지진격리받침의 균일한 품질유지 및 내진에 대한 성능검증이 뒤따라야 한다. 이를 위해 본 연구에서는 지진격리받침인 납-적층고무받침(LRB)와 적층고무받침(RB)의 전단특성 평가시험을 실시하였으며. 온도변화에 따른 전단특성 변화를 파악하기 위해 온도의존성 시험도 실시하였다. 시험후 측정값을 설계 기준값과 비교하여 전단성능에서의 오차를 조사하고, 이를 도로교 설계기준의 허용한계와 비교 분석하였다. 시험결과 지진격리받침의 상당수가 도로교 설계기준의 허용한계를 넘거나 근접해 있는 것으로 나타났다. 그리고 공용중에 전단특성을 변화시키는 온도변화에 의한 영향도 매우 큰 것으로 파악되었는데, 제작 초기의 품질오차가 이런 영향과 중첩된다면 처음 설계값보다 50% 이상 큰 전단강성 변화를 보일 가능성도 있는 것으로 나타났다.

• 한국전기전자재료학회논문지
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• 제18권8호
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• pp.759-765
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• 2005

In this paper, developed isolator for gap filler is analyzed and designed using the simulation tool. Using the designed parameters, isolator is fabricated and tested in gap filler band. Temperature characteristics of isolator depend on magnet, YIG ferrite, and conductor etc. These require temperature stability and possible method of compensation for the temperature dependent effects. The temperature stabilization tries to use Ni-alloy. Developed isolator that compare with room temperature and high temperature characteristics has change fewer than 20 MHz. Implemented isolator shows more than 20 dB isolation characteristic at center frequency(2,650 MHz) and has 0.2 dB insertion loss in overall 100 MHz operating bandwidth. Return losses of input and output port are measured below -20 dB.

• 한국추진공학회지
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• 제20권4호
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• pp.87-93
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• 2016

직접 연결식(DC) 고도모의 엔진시험 수행 시, 공기 흡입 덕트와 항공용 엔진 사이에 래버린스 씰이 설치된다. 래버린스 씰은 이 둘을 기계적으로 격리시킴으로써 주추력 및 측추력을 보다 정확하게 측정할 수 있도록 돕는다. 하지만 덕트 내부 공급공기에 높은 수직 온도구배가 발생할 경우, 래버린스 씰의 격리가 파괴되어버린다. 본 논문에서는 이러한 접촉 문제를 해결하기 위한 노력의 일환으로 래버린스 씰 온도 제어장치를 제작/설치하였다. 본 장치를 실제 항공용 엔진시험에 적용한 결과, 높은 수직 온도구배가 생성되어도 래버린스 씰의 격리가 잘 유지되는 것을 확인할 수 있었다.

• Nuclear Engineering and Technology
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• 제46권5호
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• pp.605-618
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• 2014

The effects of variability of the mechanical properties of lead rubber bearings on the response of a seismic isolation system are investigated. Material variability in manufacturing, aging, and operation temperature is assumed, and two variation models of an isolation system are considered. To evaluate the effect of ground motion characteristics on the response, 27 earthquake record sets with different peak A/V ratios were selected, and three components of ground motions were used for a seismic response analysis. The response in an isolation system and a superstructure increases significantly for ground motions with low A/V ratios. The variation in the mechanical properties of isolators results in a significant influence on the shear strains of the isolators and the acceleration response of the superstructure. The variation provisions in the ASCE-4 are reasonable, but more strict variation limits should be given to isolation systems subjected to ground motions having low A/V ratios. For application of seismic isolation systems to safety-related nuclear structures, the variation in the material and mechanical properties of the isolation system should be properly controlled during the manufacturing and aging processes. In addition, special consideration should be given to minimize the accidental torsion caused by the dissimilarity in the stiffness variations of the isolators.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 춘계학술대회 논문집
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• pp.227-229
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• 1995

Using thermal oxide SiO$_2$ as a dielectrical isolation layer, SOI Hall sensors without pn junction isolation have been fabricated on Si/SiO$_2$/Si structures. The SOI structure was formed by SDB (Si- wafer direct bonding) technology. The Hall voltage and the sensitivity of Si Hall devices implemented on the SDB SOI structure show good linearity with respect to the appled magnetic flux density and supplied current. The product sensitivity of the SDB SOI Hall device is average 600V/V.T. In the trmperature range of 25 to 300$^{\circ}C$, the shifts of TCO(Temperature Coefficient of the Offset Voltage) and TCS(Temperature Coefficient of the Product Sensitivity) are less than ${\pm}$ 6.7x10$\^$-3/ C and ${\pm}$8.2x10$\^$04/$^{\circ}C$, respectively. These results indicate that the SDB SOI structure has potential for the development of Hall sensors with a high-sensitivity and high-temperature operation.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.29-33
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• 2000

This paper describes on the temperature characteristics of a SDB(silicon-wafer direct bonding) SOI(silicon-on-insulator) Hall sensor. Using the buried oxide $SiO_2$ as a dielectrical isolation layer, a SDB SOI Hall sensor without pn junction isolation has been fabricated on the Si/$SiO_2$/Si structure. The Hall voltage and the sensitivity of the implemented SOI Hall sensor show good linearity with respect to the applied magnetic flux density and supplied current. In the temperature range of 25 to $300^{\circ}C$, the shifts of TCO(temperature coefficient of the offset voltage) and TCS(temperature coefficient of the product sensitivity) are less than ${\pm}6.7{\times}10^{-3}/^{\circ}C$ and ${\pm}8.2{\times}10^{-4}/^{\circ}C$, respectively. These results indicate that the SDB SOI structure has potential for the development of a silicon Hall sensor with a high-sensitivity and high-temperature operation.