• 동력기계공학회지
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• 제15권4호
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• pp.5-10
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• 2011

In case of using rapid vacuum-freeze drying for high quality dry flower of flowering plant, the morphological and physiological characteristics of dry rose showed as the following. The dry ratio of about 82% presented after 1 day in case of using rapid vacuum-freeze drying and it was reached that the optimum storage water content of general dry products was 18%. The dry ratio of about 89% presented after 4 days. This result indicates very short dry time comparing with natural dry time of 12 days. Also, the morphological characteristics of flowering plant in case of vacuum-freeze drying showed similar shape with real flower. The contraction decreased about 9% comparing with real flower under dry time of 72 hours. But the contraction in case of natural dry decreased 36% and showed noticeable difference. The brightness which affects physiological characteristics of dry flowering plant showed lower values according to the dry process and chromaticity was thick. After 4 days, natural dry was thick with about 2 times comparing with vacuum-freeze drying. In case of vacuum-freeze drying, the quantity of anthocyanin and chlorophyl which affect discoloration and bleaching of dry flowering plant showed the clear difference comparing with natural dry method due to the sublimation by vacuum after rapid freeze with short initial time.

• 한국식품저장유통학회지
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• 제7권4호
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• pp.389-394
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• 2000

단감의 수확 및 저장 중에 발생한 불량과실을 이용할 목적으로 분말화하기 위한 기초연구로서 본 실험을 행하였다. 일반성분 조성은 조단백질, 조지방, 조회분의 순으로 열풍건조 처리구는 0.9-1.1%, 15.0-39.0%, 2.3-3.3%이었으며, 동결건조 처리구는 1.3-2.2%, 27.0-49.0%, 2.5%로 나타났다. 무기성분 조성은 열풍과 동결건조 처리구 모두 potassium, magnesium, phosphorus; calcium, sodium이 주요 무기성분이었으며, 다른 미량원소는 약 3.00ppm 이하였다. 주요 지방산 조성은 열풍과 동결건조 처리구에서 capric acid, lauric acid tridecanoic acid, palmitic acid, palmitoleic acid, oleic acid, linoleic acid, linolenic acid 순으로 나타났다. 동결건조 처리구의 아미노산 조성은 aspartic acid, glutamic acid가 주요 아미노산이었다. 전체적으로 열풍건조 처리구보다는 동결 건조 처리구가 다소 높은 결과를 보였다. 열풍과 동결건조에 의한 분말 제조에서는 변색과 영양적인 측면을 고려할 때 열풍건조 보다는 동결건조가 우수한 결과를 보였으며, 열풍건조가 시간은 단축되었으나 얇게 펴서 건조해야 하는 단점이 있었으며, 단순한 열풍건조 만으로는 대량생산에 의한 분말 제조는 어렵고 좀더 보완적인 방법이 강구되어야할 것으로 생각된다. 이에 반해 동결건조에 의한 건조방법은 건조시간이 다소 걸리기는 했으나 딱딱해지거나 변색의 우려가 없으며 영양학적으로도 매우 안정적이었다. 이상의 결과를 평가해 볼 때 열풍건조에 의한 분말 제조는 구체적인 보완이 필요하며, 동결건조에 의한 분말 제조가 열풍건조에서보다 우수한 것으로 결과가 나타났다. 따라서, 파찌감의 분말건조 방법은 동결건조가 효율적일 것으로 생각된다.

• 한국조리학회지
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• 제12권3호
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• pp.108-118
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• 2006

This study is on different dry methods for Artemisia sp. which were not affected by the dry matter percent. Essential oil components such as 1,8-cineol and terpineol were highly affected by the dry method. 1,8-cineol and terpineol components were decreased by adaptation of the heated oven-drying method and the freeze-drying method. Borneol components were increased through shady sun-drying, sun-drying and freeze-drying. Heated oven drying method decreased the vitamin C content. Vitamin C content was decreased in oven-drying about 50% during this period, but only 10% decreased in the freezing dry method. Qualities were changed by different drying methods. Therefore, different dry methods of Artemisia sp. were applied to the flavorgen.

• Geomechanics and Engineering
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• 제28권4호
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• pp.375-384
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• 2022

The glacial tills and shales in Midwestern states of the USA often show strength degradation after construction. They are often in need of applying soil modification techniques to remediate their strength degradation with weathering process. This study investigated the weathering durability of these natural soils and biopolymer treated soils by comparing direct shear test results for wet-dry and wet-freeze-thaw-dry cycled specimens. The tests showed that untreated glacial tills maintained only 62% and 50% initial shear strength after eight wet-dry cycles and eight wet-freeze-thaw-dry cycles, respectively. These untreated soils could not withstand by themselves after 16 weathering cycles. The same soils treated with 1.5% (by dry weight) food-grade Xanthan gum maintained 140% and 88% initial shear strength of untreated soils after 16 weathering cycles for wet-dry cycles and wet-freeze-thaw-dry cycles, respectively. The same soils treated with 1.5% (by dry weight) Gellan gum maintained 82% and 60% initial shear strength of untreated ones after 16 weathering cycles, respectively. Similar results were obtained for crushed shales, manifesting that the biopolymerization method may be adopted as a new eco-friendly method to enhance the weathering durability of these problematic soils of glacial tills and shales.

• Journal of Biosystems Engineering
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• 제18권2호
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• pp.122-132
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• 1993

Effects of physical properties of garlic paste and freeze dry control parameters on the sublimation drying time were investigated to verify optimal operating method in freeze drying. A mathematical model of freeze drying by sublimation was suggested and used to estimate the drying time of garlic paste. Under various conditions, the drying time of garlic paste was calculated using the computer program for the suggested model. Among the physical properties of garlic paste, melting temperature was evaluated the most important factor in affecting the drying time. In supplying methods of the required heat energy for sublimation, it would be the best way to control the upper plate temperature and the lower plate temperature independently.

• Applied Microscopy
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• 제28권3호
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• pp.299-306
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• 1998

T-butyl alcohol (TBA) freeze-drying method originally designed by Inoue and Osadake (1989) was adopted to dry specimens for scanning electron microscopy and the results were compared with those dried using critical point dryer (CPD). Small pieces $(1\times1\times3mm)$ of liver of Sprague-Dawley rats were cut and fixed in 2% glutaraldehyde in 0.1 M sodium cacodylate buffer after anesthesia, and processed for scanning electron microscopy by several modifications of TBA freeze-drying methods and by the standard preparation method using CPD. The bile canaliculi and sinusoidal endothelial surface were observed. Tissue dehydrated with TBA before TBA freeze-drying preserved the structures best comparable to those prepared with CPD. This result suggests that combination of dehydration with TBA and TBA freeze-drying is a superior method to the original TBA freeze-drying method dehydrated with ethanol.

• 한국건축시공학회지
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• 제7권3호
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• pp.107-113
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• 2007

This study is to investigate adhesive properties depending on the temperature, humidity, and freeze-thraw of the Steel plate adhesive strengthening method by the epoxy resin. The results are summarized as following. For the temperature variation, the debonding failure appear only after 1 cycle of temperature varoation because the coefficient of thermal expansion of the epoxy resin is comparatively large, and the bonding strength is decreased. The deformation properties and ultrasonic pulse velocity on each materials are similar until 4 cycles on the dry and moisture test. As the freeze-thraw test, the epoxy resin is degraded easily subjected to freeze-thaw cycle, comparatively easy, so the debonding failure may occur in short term because of the freeze-thaw repeatition.p

• Journal of Information Display
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• 제6권2호
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• pp.19-24
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• 2005

The density controlled carbon nanotubes (CNTs) are grown on the iron acetate nanoparticles by using the freeze-dry method. The iron-acetate [Fe(II)$(CH_3COO)_2$] solution is used to prepare the catalytic iron nanoparticles. The density of CNTs is controlled in order to enhance the field emission process. Furthermore, the patterning of the iron nanoparticle catalyst-layer for the fabrication of electronic devices is simply achieved by using alkaline solution, TMAH (tetramethylammonium hydroxide). We applied this patterning process of catalyst layer to form the electron emitter with under-gate type triode structure.

• Bulletin of the Korean Chemical Society
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• 제28권1호
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• pp.99-102
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• 2007

To prepare freeze-dried ascorbyl palmitate (AsP)-containing liposome which can protect the drug from moisture attack and be used instantly by mixing with water for anti-aging and skin whitening therapy, AsP was encapsulated into liposomes and freeze-dried with trehalose. The freeze-dried liposome formulations were characterized by measuring water contents, particle size, time required for complete reconstitution. With the freeze-dried liposomes, we performed the stability test under accelerated conditions, skin permeation and localization test. The measurement of the time to perfect reconstitution showed that the freeze-dried liposomes can be changed to their initial state rapidly and short term stability test of AsP in reconstituted liposomes under accelerated conditions confirmed that the stability of AsP was considerably enhanced as compared to freshly prepared liposomes. The skin permeation and localization properties of AsP in reconstituted liposomes were not significantly different, indicating that the liposomal structures were maintained before and after freezedrying. In conclusion, the freeze-drying method provided a possible way to overcome the instability issue of AsP induced by the moisture and reproduced similar skin permeation and localization properties as shown by freshly prepared liposomes.

• 한국구조물진단유지관리공학회 논문집
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• 제12권2호
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• pp.67-74
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• 2008

본 연구에서는 탄소섬유접착보강공법의 박리와 연관한 부착특성에 대하여 검토하였다. 그 결과를 요약하면, 온도변화에 따른 변형 특성에서는 바탕 콘크리트의 강도에 관계없이 온도 변화에 따라서 각 재료들의 변형 폭도 커지는 것을 알 수 있었다. 초음파 전파 속도도 온도변화에 따라 작아지는 것으로 나타나 계면에서 박리가 발생하였음을 알 수 있었다. 부착강도는 온도 변화가 클수록 부착강도의 값은 작아지는 것으로 나타났는데, 파괴형태는 계면파괴와 모재파괴 형태로 나타났다. 건습 변화에 따라서는 4사이클까지 각 재료의 변형 및 초음파 전파 속도에서 큰 변화를 나타내지 않아 건습 자체의 반복에는 큰 영향이 없는 것으로 판단된다. 단, 부착강도는 40%정도 저하하는 것으로 나타났지만 비교적 양호한 강도를 나타내었다. 동결융해 시험결과는 온도변화 요인과 유사한 경향으로서 동결융해 작용을 받을 경우 4사이클 이내에 박리가 일어날 수 있는 것으로 분석되었다.