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        검색결과 78

        2.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Physicochemical properties and storage stability of plant-based alternative meat prepared with low-fat soybean powder (LPAM) treated by supercritical-CO2 and those of full-fat soybean powder (FPAM) were compared. Ash and crude protein contents were higher in LPAM than in FRAM. Water absorption capacity and oil absorption capacity were significantly higher in LPAM than in FPAM. Water binding capacity was higher in LPAM than in FPAM during a 20 days storage period at 5℃ and pH was significantly lower in LPAM than in FPAM after a 5~10 days storage period. Hardness, gumminess and chewiness significantly increased with the increase in the storage period, and the three were significantly higher in LPAM than in FPAM after 10 days and 20 days of storage. The acid value showed no remarkable difference according to the storage period in LPAM; however, it was significantly higher in FPAM than in LPAM after 20 days of storage. The peroxide value and TBA value were significantly increased according to the storage period, and were significantly lower iin LPAM than in FPAM during all the storage periods. Therefore, the use of low-fat soybean powder may be effective in improving oxidative stability during storage in the production of plant-based alternative meat.
        4,000원
        3.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to respond to environmental pollution, developed countries, including Korea, have begun to conduct research to utilize hydrogen energy. For mass transfer of hydrogen energy, storage as liquid hydrogen is advantageous, and in this case, the volume can be reduced to 1/800. As such, the transportation technology of liquefied hydrogen for ships is expected to be needed in the near future, but there is no commercialized method yet. This study is a study on the technology to test the performance of the components constituting the membrane type storage container in a cryogenic environment as a preparation for the above. It is a study to find a way to respond by analyzing in advance the problems that may occur during the shear test of adhesives. Through this study, the limitations of ISO4587 were analyzed, and in order to cope with this, the specimen was supplemented so that fracture occurred in the adhesive, not the adhesive gripper, by using stainless steel, a low-temperature steel, to reinforce the thickness. Based on this, shear evaluation was performed under conditions lowered to minus 243℃, and it was confirmed that the breaking strength was higher at cryogenic temperatures.
        4,000원
        4.
        2023.05 구독 인증기관·개인회원 무료
        For Korean nuclear fuel cycle project, it is necessary to design and evaluate the integrity of spent fuel storage. For the design and evaluation of spent fuel storage, it is necessary to evaluate the properties of various materials used in spent fuel storage. The materials previously considered in the design of nuclear power plants were limited to static properties and were listed in design and manufacturing code and standards. However, for the evaluation of the storage containers in scenarios such as transportation and events, dynamic material property evaluations are required. Research on the dynamic properties of materials is generally conducted in the fields of automotive and aerospace, and most of the studies are on metal materials under sheet conditions. Since the structural materials of the storage containers for used nuclear fuel are mostly composed of thick materials, consideration should be given to property evaluation methodology and quantitative comparison. In this study, the mechanical properties of stainless steel material with canister application were evaluated according to the strain rate, and the crack resistance evaluation was also performed. It was confirmed the changes in strength and crack resistance according to the increase in strain rate and observed differences in microstructural hardening behavior.
        6.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        예로부터 식품과 한약재로 널리 활용되어 온 매실은 호흡급등형 과실로 수확 후 상온에서 보관하면 며칠 내로 황변이 발생하고 물러지는 등 후숙이 빠르게 진행된다. 본 연구는 이러한 후숙이 진행될 때 수확 당시 색도가 품질과 영양적인 측면에 미치는 영향과 보관 조건에 따른 변화의 정도를 비교・분석하고자 한다. 이를 위해 같은 날에 수확한 매실을 색도에 따라 청매와 황매로 구분하고 상온, 냉장, 냉동 보관하는 동안에 발생되는 물리・화학적인 변화를 조사하였다. 수확 당일의 측정값과 비교하여 10~15% 이상 변하는데 소요되는 시간을 고려하면, 매실의 물성 변화는 저장기간 전반에 걸쳐 수확일의 색도 차이에 따라 뚜렷한 영향을 받지 않는 것으로 나타났다. 모든 저장 온도 조건에서 수확일과 비교한 실험일의 경도 감소가 가장 두드러졌고, 색도와 사과산의 변화도 빠르게 진행되었으나, 가용성 고형분과 pH의 변화는 거의 나타나지 않았다. 매실은 상온 보관의 경우 대략 4일 이내, 냉장 저장의 경우 대략 20일 이내에서 물성의 변화가 약 10% 이하로 적게 나타나며 품질을 유지하는 것으로 나타났다. 냉동 저장의 경우 색도와 경도는 저장 초기에 급격히 변하지만, 다른 물성은 대체로 장기간 유지되었다. 따라서 본 연구 결과를 토대로 저장 조건에 따른 물성 변화를 고려하여 매실의 저장 방법과 적절한 사용 시기를 결정할 것을 제안한다.
        4,300원
        9.
        2022.10 구독 인증기관·개인회원 무료
        Some Spent Fuel Pools (SFPs) will be full of Spent Nuclear Fuels (SNFs) within several years. Because of this reason, building interim storage facilities or permanent disposal facilities should be considered. These storage facilities are divided into wet storage facilities and dry storage facilities. Wet storage facility is a method of storing SNF in SFP to cool decay heat and shielding radiation, and dry storage facility is a method of storing SNF in a cask and placing on the ground or storage building. However, wet storage facilities have disadvantages in that operating costs are higher than that of dry storage facilities, and additional capacity expansion is difficult. Dry storage facilities have relatively low operating costs and are relatively easy to increase capacity when additional SNFs need to be stored. For this reason, since the 1990s, the number of cases of applying dry storage facilities has been increasing even abroad. Dry storage facilities are divided into indoor storage facilities and outdoor storage facilities, and outdoor storage facilities are mostly used to take advantage of dry storage facilities. In the case of outdoor storage facilities, the cask in which SNFs are stored is placed on a designed concrete pad. During this storage, the boring heat generated by SNFs cools into natural convection and the cask shields the radiation that SNFs generates. However, if an accident such as an earthquake occurs and the cask overturns during storage, there may be a risk of radiation leakage. Such a tip-over accident may be caused by the cask slipping due to the vibration of an earthquake, or by not supporting the cask properly due to a problem in the concrete pad. Therefore, in the case of outdoor dry storage facilities, it is necessary to evaluate the seismic safety of concrete pads. In this paper, various soil conditions were applied in the seismic analysis. Soil conditions were classified according to the shear wave velocity, and the shear wave velocity was classified according to the ground classification criteria according to the general seismic design (KDS 17 10 00). The concrete pad was designed with a size that 8 casks can be arranged at regular intervals, and 11# reinforcing bars were used for the design of the internal reinforcement of the concrete pad according to literature research. The cask was designed as a rigid body to shorten the analysis time. The soil to which the elastic model was applied was designed under the concrete pad, and infinite elements were applied to the sides and bottom of the soil. The effect on the concrete pad and cask by applying a seismic wave conforming to RG 1.60 to the bottom of the soil was analyzed with a finite element model.
        10.
        2022.05 구독 인증기관·개인회원 무료
        Concrete structures of spent nuclear fuel interim storage facility should maintain their shielding ability and structural integrity during normal, off-normal and accident conditions. The concrete structures may deteriorate if the interim storage facility operates for more than several decades. Even if deterioration occurs, the concrete structures must maintain its unique functions (shielding and structural integrity). Therefore, it is necessary to establish an analysis methodology that can evaluate whether the deteriorated concrete structure maintains its integrity under not only normal or off-normal condition but also accident condition. In accident conditions such as tip over and aircraft collision, both static material properties and dynamic properties of the concrete are required to evaluate the structural integrity of the concrete structures. Unlike the calculated damage results for the static deformation of the concrete structure, it is very difficult to accurately estimate the damage values of the degraded concrete structures where an aircraft collides at a high strain rate. Therefore, the present authors have a plan to establish a database of the dynamic material properties of deteriorated concrete and implement to a Finite Element Analysis model. Prior to that, dynamic increase factors described in a few technical specifications were investigated. The dynamic increase factor represents the ratio of the dynamic to static strength and is normally reported as function of strain rate. In ACI-349, only the strain rate is used as a variable in the empirical formula obtained from the test results of specified concrete strengths of 28 to 42 MPa. The maximum value of dynamic increase factor is limited to 1.25 in the axial direction and 1.10 in the shear direction. On the other hand, in the case of the CEB model, static strength is included as variables in addition to the strain rate, and a constitutive equation in which the slope changes from the strain rate of 30 /s is proposed. As plotting the two dynamic increase factor models, in the case of ACI, it is drawn as a single line, but in the case of CEB, it is plotted as multiple lines depending on the static strength. The test methods and specimen sizes of the previously performed tests, which measured the concrete dynamic properties, were also investigated. When the strain rate is less than 10 /s, hydraulic or drop hammer machines were generally used and the length of the specimens was more than twice the diameter in most cases. However, in the case of Split Hopkinson Pressure Bar tests, the small size specimens are preferred to minimize the inertia effect, so the specimens were small and the length was less than twice the diameter. We will construct the dynamic properties DB with our planned deteriorate concrete specimen test, and also include the dynamic property data already built in the previous studies.
        12.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This research aims to investigate pudding with grain-added yogurt for its quality characteristics and viability during cold storage. The yogurt was fermented until its pH was 5.10±0.05 after inoculating the probiotic strain (Bifidobacterium lactis, BB-12) into the milk base containing grains. The yogurt was added to prepare probiotic puddings. During cold storage of the puddings at 4±1oC for 4 week, the quality characteristics (pH, acidity, texture) and the viability of BB-12 in pudding were determined and compared to control (only milk base). As a result, MR had a significantly lower pH and higher acidity than those of other samples. In texture properties, including hardness, gumminess, and chewiness, MSIR showed the significantly highest value, and the pudding with inulin was significantly higher than rice flour in all textures. For the viability of BB-12, pudding with milk was significantly lower than pudding containing milk and soymilk, suggesting that soymilk helps maintain viability. MR showed significantly higher viability than MI in the milk-based pudding, indicating that rice flour is more effective than inulin. Therefore, the addition of soymilk, inulin, and rice can maintain quality characteristics and viability of BB-12 in the pudding.
        4,000원
        14.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to investigate milling's effect on the pasting properties and storage stability of dry-milled rice flour. Rice flour's moisture content was increased from 9.48% to 9.80% after going through a rice polisher, and the crude fat content of rice flour was decreased from 0.91% to 0.62% after going through a rice polisher. In the color index of rice flour, the rice polisher was only affected by yellowness. The pasting properties were verified through RVA, and it was confirmed that the use of a rice polisher had no significant effect on the pasting properties. As a result of observing the changes in fatty acid value, it was ascertained that the storage period could be increased using the rice polisher. These results suggest that the rice polisher can increase the storage period without changing the pasting properties.
        4,000원
        15.
        2020.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to investigate the changes of the microbiological contamination levels, pH, acidity, solid contents, total phenol contents, and color difference of cold-brew coffee products during 4 weeks at room and cold temperatures. The 17 sample coffees were purchased from regional cafes in Jeonju. Each coffee was self-blended by the cafes. Esherichia coli was not detected in all the samples, but bacteria were detected in 1 sample and yeast and molds were detected in 4 samples. Of the samples stored at room temperature (25oC) after 4 weeks, general bacteria were detected in 4 samples (3.0×101 cfu/ml-1.7×103 cfu/ml), and yeast and molds were detected in 11 samples (1.3×101 cfu/ml - 3.1×105 cfu/ml). In the case of the samples stored at cold temperature (4oC), general bacteria were detected in 3 samples, and yeast and molds were detected in 6 samples although the level of contamination was lower than that at room temperature. pH and acidity decreased during the storage period, but the total phenol content did not change. In the case of chromaticity, redness and yellowness tended to decrease.
        4,000원
        16.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examined the optimal temperature and time conditions to maintain high quality Dongchimi during the fermentation and storage period. Dongchimi was fermented at low (5oC), medium (10 and 15oC), and high (20oC) temperatures until the acidity reached 0.2, 0.3, and 0.4%. respectively. From the consumer’s preference test enrolling five consumers, Dongchimi fermented at 15oC until an acidity of 0.3% (for approximately six days) was evaluated to be the optimal status because of its high score of overall acceptance, taste, and odor of consumers. To determine the optimal storage temperature of fermentation, Dongchimi was stored at three different temperatures (−1, 2, 5oC) for four weeks after fermenting at 15oC for six days. During the storage period, most of the physicochemical properties (pH, acidity, reducing sugar content, and organic acid) and microbiological properties changed significantly in the 2 and 5oC groups, resulting in a significant change in descriptive sensory analysis of Dongchimi. These results indicate that fermentation at 15oC and storage at −1oC for Dongchimi enables it to maintain the best quality for a long time.
        4,000원
        17.
        2019.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study examines paraelectric Bi1.5Zn1.0Nb1.5O7 (BZN), which has no hysteresis and high dielectric strength, for energy density capacitor applications. To increase the breakdown dielectric strength of the BZN film further, poly(vinylidene fluoride) BZN-PVDF composite film is fabricated by aerosol deposition. The volume ratio of each composition is calculated using dielectric constant of each composition, and we find that it was 12:88 vol% (BZN:PVDF). To modulate the structure and dielectric properties of the ferroelectric polymer PVDF, the composite film is heat-treated at 200 oC for 5 and 30 minutes following quenching. The amount of α-phase in the PVDF increases with an increasing annealing time, which in turn decreases the dielectric constant and dielectric loss. The breakdown dielectric strength of the BZN film increases by mixing PVDF. However, the breakdown field decreases with an increasing annealing time. The BZN-PVDF composite film has the energy density of 4.9 J/cm3, which is larger than that of the pure BZN film of 3.6 J/cm3.
        4,000원
        18.
        2018.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Quality changes in yakgwa (such as color, moisture contents, acid value, rheological properties, and viable cells) using different types of frying oils was examined for 5 weeks. During the storage period, the lightness and yellowness of all samples were increased and there was no significant difference in redness. After 5 weeks of storage, rice bran oil showed the least color difference. There was no difference in the moisture contents of all samples except for grape seed oil, while the moisture contents of yakgwa fried with grape seed oil was decreased. The acid value increased as the storage period increased regardless of the type of frying oil, and yakgwa fried with rice bran oil and grape seed oil showed a low acid value. The hardness was increased as the storage period increased, but there was no difference in the hardness between the samples. The adhesiveness and resilience were decreased and the chewiness was increased. The total cell count did not increase significantly as the storage period, and there was also no difference in the total cell count between the samples. There was a high level of yeast and mold in comparison to total cell count, and the colony of bacteria was not detected.
        4,000원
        19.
        2017.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Liquid storage tank is one of the major infrastructures and generally used to store gases, drinking and utilizing water, dangerous fluids, fire water and so on. According to the recent reports and experiences, the tank structures are damaged in many earthquakes due to their low energy dissipating capacity. Therefore, many researchers have been tried to know the dynamic properties of the tanks including liquids. However, vary limited experimental studies are carried out using relatively small tank models. In this study, a series of shaking table tests are performed with maximum 2 m cubic rectangular liquid storage tanks made of steel to measure the natural frequency and estimate damping coefficient of impulsive and convective mode of the tanks. Especially, the damping values under different shapes and excitation methods are estimated by logarithmic decrement method and half power band-pass method and compared with current design code and standards such as ASCE 7, Eurocode 8 and NZS. Test results show that the impulsive mode damping is around 2% which is proposed by general standards and codes but the impulsive mode damping is 0.13% average that is slightly lower than the code recommendation.
        4,000원
        20.
        2017.04 구독 인증기관·개인회원 무료
        The effects of high hydrostatic pressure (HHP) or concentration treatment or sodium hydrogen carbonate addition on microbial and quality properties of cold drip liquid coffee were investigated during storage at room temperature. Cold drip liquid coffee was determined to pH, acidity, general bacteria, and Y&M (Yeast and Molds) according to HHP treatment or adding 0.2% sodium hydrogen carbonate for 40 days storage at 20°C. Also, an equivalent mixture of concentrated coffee and cold drip liquid coffee or liquid coffee with 0.2% sodium hydrogen carbonate was used for determining the sensory evaluation, due-trio and preference test. The cold drip liquid coffee with 0.2% sodium hydrogen carbonate had higher pH and lower titratable acidity than the control during 40 days storage at 20°C. Total viable cell and Y&M counts of cold drip liquid coffee added with 0.2% sodium hydrogen carbonate or treated by HHP at 300 MPa for 25 min were lower than the control during storage at 20°C. The result of the due-trio and preference tests shows that there was no significant difference between cold drip liquid coffee added to 0.2% sodium hydrogen carbonate and the control or between the equivalent mixture of concentrated coffee with cold drip liquid coffee and the control. As a results, Cold drip liquid coffee treated by HHP, concentrated by evaporation, and added to sodium hydrogen carbonate has a potential to extend a shelf life at ambient temperature storage.
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