• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.2
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• pp.119-128
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• 2023

This study was examined for investigating the quality changes of spring kimchi cabbage under various treatments (pre-drying/pre-cooling, packaging types, and stacking and loading in container and pallete in the storage room) during cold storage. The results showed that control (upward stacking without pre-drying/pre-cooling and HDPE or PVC film cover) was increased significantly in weight loss and trimming loss, compared to other treatments such as DPDH (downard stacking + pre-drying + HDPE), DPDP (downard stacking + pre-drying + PVC), DPCH (downnard stacking + pre-cooling + HDPE), and UPCH (upward stacking + pre-cooling +HDPE) during storage for three months. In Sensory evaluation, judging from marketable properties, the desirable appearance of spring kimchi cabbage with the modified pallet-unit MA packed, PE, and PVC film wrapping could be maintained until 9 weeks after pre-drying/pre-cooling. Meanwhile, the control without any treatments after 6 weeks, the sensory score was declined, significantly. In general, the low temperature (10℃ and 2℃) of pre-treatment with combination of plastic film packaging in spring kimchi cabbage storage could inhibit the physiological activity and reduce the direct exposure of environmental cold air in the storage. Therefore, these two variables were the key points for extending the shelf-life of spring kimchi cabbage.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.458-463
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• 1996

Fresh ginger harvested in Seosan, Choongchengnam-do, was used to investigate the pretreatment effect before long-term storage. Wounded ginger were cured at the temperature of 25, 30, $35^{\circ}C$ and the RH 83 and 93% for 1, 3, 5, 7 days, respectively Then the cured ginger were stored in the laboratory scale storage room ($12^{\circ}C,$ 95% RH) in order to find out the optimum curing condition. At a constant temperature and a RH. the longer ginger were cured, the more their weight was decreased; at a constant temperature and a curing period, the higher RH was, the less weight was lost. During the curing process, sprouting rate was accelerated at temperature higher than $30^{\circ}C$ and humidity higher than 90%; mold growing was observed at any temperature and humidity, but especially at $35^{\circ}C$ the rate was relatively faster when the curing time was increased. Hardness of wound surface cured at 93% RH was relatively higher than those cured at 83% RH at all temperatures. The weight loss of store ginger after curing was $2.0{\sim}8.2$ after 30 days and $7.2{\sim}14.2%$ after 60 days storage. Compared with all results through a screening procedure, the condition of 3-days curing at $25^{\circ}C$ and 93% RH showed th best result for minimizing quality changes during storage.

• Korean Journal of Food Science and Technology
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• v.46 no.5
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• pp.593-600
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• 2014

Normal rice starch (NRS) possesses high gelling and retrogradation tendencies, with poor freeze-thaw stability. This study investigated the effects of partial replacement of waxy rice starch (WRS) with gums on the pasting and viscoelastic properties as well as the freeze-thaw stability of the WRS paste. Xanthan gum (XAT), locust bean gum (LBG), and their mixtures were individually mixed with WRS at a ratio of 1:19 (w/w). WRS-gum mixtures were pasted using a rapid visco-analyzer at 5% total solid content, and analyzed with respect to the pasting and viscoelastic characteristics, and freeze-thaw stability. Pasting properties of WRS were retarded in pasting temperature and enhanced in pasting viscosity (although peak viscosity was varied) by partial replacement with gum and gum mixtures. Storage moduli of WRS-XAT:LBG pastes became similar to those of NRS paste with increasing angular frequency from 1 to 10 rad/s. Finally, WRS-XAT and WRS-XAT:LBG possessed more enhanced freeze-thaw stability than NRS.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.109-109
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• 2019

2018년 5월 전라북도 남원군에서 재배하여 수확 후 $0^{\circ}C$ 저장고에서 예냉을 마친 산마늘을 사용하였으며 외 포장 상자는 골판지로 구성된 통기공이 없는 골판지상자 1kg용을 사용하였다. 골판지상자와 함께 내부 포장으로 사용하기 위한 내포장 필름은 $20{\mu}m$ 두께의 HDPE으로 된 필름 봉지, 흡습종이는 파라핀왁스 코팅 종이($32{\times}35cm$, 태영산업)를 이용하여 조합 처리하고 국내에서 개발한 기능성 필름2종으로 포장처리는 총 4가지로 (1) PE(관행) (2) PE+흡습지 (3) 기능성필름1($30{\times}58cm$, 기능성물질 1%+40,000OTR, 제조사: 신영산업사) (4) 기능성필름2($30{\times}58cm$, Key fresh, 제조사: 씨앤케이프로팩(주)) 각 처리당 1kg 씩의 산마늘 잎을 포장하였다. 실험은 포장 처리 후 상온상태로 전북 완주군 실험실까지 수송하였으며 실험실 도착 후 상온 실험실에 두고 2일과 6일 후 중량감소율, 색도, 엽록소, 손실률 및 종합선도 등 품질특성 변화를 조사하였고 각 포장방법별 온도와 상대습도 변화를 보기 위하여 산마늘 잎이 포장된 상자 내부 중앙 부분에 디지털온습도기록계(SP-2000-20R)를 고정한 후 측정하였다. 대조구로 사용한 PE필름 단용으로 포장한 산마늘 잎은 상온저장 6일 경과 후 중량 소율이 1.7%, PE필름+신선지 처리는 1.0%, 기능성필름1과 기능성필름2는 거의 중량감소가 없어 1% 미만의 변화를 보였다. 산마늘 잎의 SPAD 값에 의한 엽록소 수치와 색도를 측정한 명도($L^*$)와 Hue angle 값의 변화는 기능성필름1과 기능성필름2가 유사하게 높게 유지되었고 반면에 PE필름은 저장 2일 후 부터 값이 감소하기 시작하여 6일 후 크게 감소하였다. 저장 6일 후 기능성필름1과 기능성필름2가 외관품위에서 높은 평가를 받아 상품성을 유지하고 있었으나 PE필름 처리와 PE필름+흡습지 처리는 상품성을 상실한 상태였다. 이러한 경향은 건전율에 있어서도 유사하였으며 기능성필름1(다공성 나노 물질이 혼입되어 있으며 산소투과율을 $40,000cc/m2{\cdot}day{\cdot}atm$으로 조성한 필름)이 상온저장 6일 후 상품성을 유지하는 건전율이 83%로 가장 높았다.

• Transactions of the KSME C: Technology and Education
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• v.4 no.2
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• pp.123-130
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• 2016

Unitex is widely used for the floor structure of urban railway vehicles because it shows good structural safety and heat insulation, has long life, and lowers the cost owing to easy installation. However, in spite of these merits, Unitex has a limit to the sound insulation performance, which is very important in vehicle structure. It shows a sound transmission loss considerably lower than the mass law value, which indicates the sound insulation performance per unit weight. Recently, railway vehicle manufacturers and Unitex supplier have tried to improve the sound insulation performance of Unitex, but meaningful results have not been achieved yet. Through the industry-university collaborative research, we propose structural improvement methods to increase the sound transmission loss by more than 5dB and we then verify the effect by performing experiments.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.12
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• pp.1931-1936
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• 2010

In Korean tilting trains, honeycomb composite panels are used for high speed and light weight. The side wall of a tilting train consists of an aluminum honeycomb coated with carbon-fiber-reinforced epoxy skin and a nomex honeycomb panel as the main structure, with glass wool inserted between the panels. In this study, based on ASTM E2249-02, we measure the intensity sound transmission loss (TL) of the honeycomb composite panels. Using mass law deviation (MLD), we estimate the sound insulation performance of the honeycomb composite panels in terms of their weight and explore the feasibility of substituting a conventional corrugated steel panel. The transmission-loss data of the honeycomb composite panels obtained in the study will be used to establish noise-reduction measures for train compartments.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.63-70
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• 2015

Crevices between window and window frame cause not only heat losses but also serve path to sound transmission and infiltration of fine dusts that are harmful to humans. There were many efforts in the past to eliminate these crevices but because of the windows' indispensable function of opening and closing, it was an unsolvable problem. In this study, a new type sliding window is developed by applying horizontally rolling wheels to implement a surface sealing which is excellent for enhancing air tightness. To evaluate the feasibility of the newly developed window, forces for opening and closing, durability and air tightness were testet according to Korean Testing Standards. Force for opening a 2000 N window is 30 N. It endured 100,000 cycles of opening and closing. Infiltration was $0.00m^3/(m^2h)$ for a pressure difference of 10 Pa. Since this window has few moving parts, it has favorable features of low cost and few breakdown.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.5
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• pp.49-57
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• 2020

Conventional electric motors are not suitable for aircraft because of their large size and weight. High-temperature superconducting (HTS) motors have high current density, high magnetic field density, and low loss, so they can significantly reduce the size and weight compared to general electric motors. This paper presents the conceptual design and analysis results of HTS motors for electric propulsion in future aircraft. A 2.5 MW HTS motor with a rotational speed of 7,200 RPM was designed and the specific power (kW/kg) was analyzed. The operating temperature of the field coil of the HTS motor is 20K in consideration of LH2 cooling. The stator winding were connected in a multi-phase configuration and Litz wires were used to minimize eddy current losses. As a result, it was confirmed that the specific power of the motor is about 18.67 kW/kg, which is much higher than that of the conventional electric motor.

• Food Engineering Progress
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• v.15 no.3
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• pp.235-242
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• 2011

This study was conducted to investigate the quality characteristics of cookies added with different levels of flaxseed powder. Cookies were prepared with four different levels (0%, 6%, 12% and 18%) of flaxseed powder and the physicochemical properties were examined. The pH of cookie dough was higher in cookies containing flaxseed powder. The spread factor of control cookie was lower than that of cookies containing 6%, 12% and 18% of flaxseed powder. The incorporation of flaxseed powder in cookies lowered lightness and yellowness but increased redness values. Rheology testing showed that cookies with 6%, 12% and 18% flaxseed powder had significantly lower hardness value than control cookies (p < 0.05). Consumer acceptance test revealed that overall preference score was the highest in cookies containing 12% flaxseed powder. During storage at $55^{\circ}C$ for 60 days, peroxide value increased until 30 days of storage and decreased thereafter, while acid value steadily increased and there was no significant difference in peroxide value and acid value between control cookies and flaxseed added cookies.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.275-278
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• 2005

In this study, the dynamic properties of a floor impact sound isolation pad expressed in terms of the natural frequency, the dynamic stiffness per unit area and the loss factor are measured by the resonant method. By using the measured dynamic properties, the vibration transmissibility diagram is obtained for each isolation pad, which is compared with the values tested by the impact sound sources at the room in an apartment. From the comparative results, it is found that the noise reduction Performances. of isolation pads are closely connected with the natural frequency and the dynamic stiffness per unit area.