In order to cope with climate change, the UN Climate Summit announced a policy to reduce carbon emissions to 0% by 2050. As a result, hydrogen energy is attracting attention as a new energy. Hydrogen energy is one of the future clean energy sources and is the most abundant and ideal fuel on Earth that does not emit pollutants. On the other hand, there is a risk of wide explosion range, easy ignition, and fast flame speed. As a result, There is limited use of hydrogen gases, and research is being conducted to safely use hydrogen gases. However, the localization rate of hydrogen-related equipment parts is low and dependence on foreign countries is high. In order to reduce dependence on foreign countries, this study designed and analysis a model of ultra-high pressure relief valve, which is a safety device for hydrogen charging stations. In order to evaluate the structural stability, a spring, a valve disk, a valve guide, and a valve spindle, which are components of an ultra high pressure relief valve, were applied with pressure resistance test and water pressure test criteria according to KS B ISO 19880-3, and analyzed using an Ansys workbench 2021 R1. Through the analysis results, the structural stability of the relief valve under the water pressure test and the pressure resistance test conditions confirmed.

By applying super-high pressure (150-250 MPa) to a sealed pressure vessel, it is possible to make oyster shucking machine that automatically opens two-sheet shellfish or oysters. Possibility of developing a shucking machine was confirmed by identifying the working pressure for meat of oysters produced in the southern coast and conducting sensory evaluation of meat oysters. As a result of confirming the shucked oysters under super-high pressure of 150 MPa in the pressure vessel, the number of type A with separated shells and well-separated meat was 22 and type B with both shells and internal meat and shells not separated. For the oysters that were treated at 175 MPa, there were 58 type As with shell separated and meat well separated and 42 type Bs without oyster shells and insides. When looking at the oysters shucked at 200 MPa in the pressure vessel, the number of type A was 86 and type B was 14 accounting for 86% of oysters with good marketability. As a result of shucking oysters by applying 250 MPa, 96% type A oysters and 4% type B oysters were obtained from the total specimen. The total specimen oyster weight used in the conducted experiment was 6 kg, the average oyster shell weight was 3.99 kg and the average oyster meat weight was 1.25 kg. Therefore, the fatness of oyster meat, which measures the added value of oysters, is 20.8%. Sensory evaluation was conducted on thinned oysters by hand and type A oysters shelled by machine with an operating pressure of 200 MPa. The hand-worked oyster sample scored 4.7 points only in salty taste, and scored 5.0 or higher in color, shape, smell, fishy taste, texture and preference.

This study examined the combined effects of high hydrostatic pressure (HHP) and micro-perforated (MP) film packaging on the microbiological and physicochemical qualities of kimchi sauce stored under fluctuating temperature conditions. Before storage, treatment with 600 MPa HHP reduced the total lactic acid bacteria in the sauce samples to below the detection limit (1 log CFU/g). After 68-day storage, ten microbial strains isolated from the non-treated controls were identified as Pediococcus pentosaceus, whereas eight microbial strains isolated from the HHP-treated samples were identified as Bacillus spp., regardless of the packaging type. Additionally, the samples treated with HHP and packaged in a multilayer film bag (ML-HPP), as well as those in the MP-HHP group, exhibited higher pH values and reduced sugar content than the ML-control or MP-control after 68-day storage. No significant differences were observed between the control and treatment groups regarding their electrical conductivity, salinity, and CIE a* values at the end of storage. However, there was no O2 reduction or CO2 accumulation in the MP-HHP group after 68-day storage. These results indicate that the combination of HHP treatment and MP-film packaging can extend the kimchi sauce's shelf life without packaging expansion during long-term storage.

The purpose of this study was to optimize the rice protein extracted using a response surface methodology. The experiment was designed based on a CCD (Central Composite Design), and the independent variables were the high pressure (X1, 0-400 MPa) and processing time (X2, 0-10 minutes). The results of the extraction content (Y1), residue content (Y2), and recovery yield (Y3) were fitted to a response surface methodology model (R2= 0.92, 0.92, and 0.93, respectively). Increasing the pressure and processing time has a positive effect on the extraction content (Y1), residue content (Y2), and recovery yield (Y3). Therefore, these high-pressure conditions (independent variables) can significantly affect the improvement in rice protein extraction efficiency. Thus, the optimal conditions of X1 and X2 were 400 MPa and 10 min., respectively. Under these optimal conditions, the predicted values of Y1, Y2, and Y3 were 62.93, 57.53 mg/g, and 91.76%, respectively.

This study was carried out to produce stable evening primrose oil in water emulsion by using various emulsifier with HLB (8.6, 12, 16.7), concentration (0-45%) and emulsification methods such as high-speed emulsification (7,000 rpm, 2 min) and high-pressure homogenization (10,000 psi, 1 cycle). And then properties of evening primrose oil in water emulsion was evaluated with keeping at room temperature and 40oC during 28 days. Lower HLB 8.6 and high viscosity emulsifier added emulsions were not appropriate for high-pressure homogenization and were separated in a day. The optimum emulsification condition was HLB 12 and high-pressure homogenization (10,000 psi, 1 cycle) for evening primrose oil in water emulsion. These emulsions produced by optimum condition were not separated with the aqueous phase and the oil phase and they were nano-sized around 200 nm, higher zeta-potential (±mV), mono-polydispersed (<0.3), and less oxidized (<0.4) during 28 days.

The 3-way valve have been used as a valve for opening and closing the valve by the flow control in the pressure system of the cryogenic and high pressure environment. In this paper, numerical analysis and experimental study on fracture nipple of 3-way ultra high pressure valve applied to space launch vehicle was carried out. We have developed a 3-way valve numerical simulation modeler of cryogenic environment using commercial software ANSYS 18.2. As results of numerical analysis, optimum nipple condition was derived. In addition, a 3-way valve prototype was fabricated and the fracture test was performed and compared with the numerical analysis results.

Using a high pressure homonizer, we report on the electrochemical performance of Li4Ti5O12(LTO) particles manufactured as anode active material for lithium ion battery. High-pressure synthesis processing is performed under conditions in which the mole fraction of Li/Ti is 0.9, the synthesis pressure is 2,000 bar and the numbers of passings-through are 5, 7 and 10. The observed X-ray diffraction patterns show that pure LTO is manufactured when the number of passings-through is 10. It is found from scanning electron microscopy analysis that the average size of synthesized particles decreases as the number of passings-through increases. LiCoO2-based active cathode materials are used to fabricate several coin half/full cells and their battery characteristics such as lifetime, rate capability and charge transfer resistance are then estimated, revealing quite good electrochemical performance of the LTO particles as an effective anode active material for lithium secondary batteries.

녹말의 열 유도 호화의 경우, 과립의 팽창은 비가역적으로 되고 입상 구조는 현저하게 변화된다. 초고압(high hydrostatic pressure, HHP)는 열처리 녹말의 약점인 외부 구조의 붕괴를 보완 할 수 있다. HHP 처리 녹말은 과립 구조를 유지하고 열처리 녹말보다 아밀로오스 방출량이 적다. 전분-물 혼합물의 압력 유도 호화는 녹말, 녹말 함량, 처리 압력, 온도 및 시간 등에 따라 현저하게 달라진다. 따라서 HHP 처리된 녹말의 적용을 증가시키기 위해서는 HHP처리로 호화되는 녹말의 호화 동력학을 이해하는 것이 매우 중요하다. 본 연구의 목적은 초고압 하에서 다양한 전분-물 혼합물의 호화 특성 동역학을 밝히는 것이다. 세 종류의 전분(Corn, Tapioca, Wheat)의 수분함량조건 (50 %, 70 % MC)을 달리하여 25℃의 HHP(350 ~ 550 MPa)하에서 0 ~ 60 분간 처리하고 이들의 호화특성을 분석하였다. 호화 온도 변화 (onset, ; peak, ; and end, ), 호화 엔탈피(ΔHgel) 및 호화도(GD)를 시차 주사 열량계(DSC)를 사용하여 측정하였다. 또한, 형태 학적 변화 및 복굴절 손실은 각각 광학 현미경과 편광 현미경을 사용하여 조사하였다. 대부분의 조건에서 일정한 시간에서 호화도는 압력이 증가함에 따라 증가하였고, 수분함량이 증가함에 따라 호화도가 증가하였다. 옥수수 전분의 경우 수분 함량 70%의 조건에서 550 MPa로 5분의 처리시간에서 완전한 호화가 이루어졌다. 550 MPa를 제외하고 일정한 압력에서 호화도는 처리시간이 증가함에 따라 증가하였다. 이로 보아 550 MPa의 처리는 옥수수 전분(70 % MC)의 완전한 호화에 충분한 압력으로 확인되었다. 는 부분 호화로 인해 고온으로 이동하였으나 와 는 크게 변하지 않았다. 타피오카의 경우 위의 결과들과 대부분 비슷한 경향성을 나타냈지만 옥수수 보다 압력에 처리에 더 내성이 있는 것으로 보여졌다. 반면 밀의 경우에는 오히려 옥수수와 타피오카에 비해 낮은 압력에서도 호화도가 높게 나타나 다른 녹말보다 압력에 더 민감한것으로 분석 되었다. 한편, 복굴절의 손실은 DSC 열 특성과 완전히 일치하지 않아 두 물리적 특성 사이에 지연이 있음을 나타낸다. 이 결과는 여러 종류의 전분 - 물 시스템의 압력 유도 젤라틴 화 메커니즘에 관한 기본적이고 기본적인 정보를 제공한다. 또한, 이 연구는 깨끗한 전분에 대한 새로운 물리적 변형 방법을 개발하는데 기여할 것이다.

인삼을 야생에서 재배한 산양삼(cultivated wild Panax ginseng, CWPG)은 여러 논문에서 인삼보다 전반적으로 높은 Ginsenoside 함량을 갖는다고 보고되었다. 그러나 이미 널리 알려져 있는 인삼이나 홍삼과는 달리 산양삼에 대한 연구는 미비하다. 본 연구의 목적은 산양삼의 유효성분 증진을 위하여 다양한 종류의 산을 상압 및 초고압 조건에서 처리하여 산처리 산양삼을 제조하고 그 진세노사이드 및 항산화 특성을 연구하는 것이다. 시료로 사용한 산양삼의 일반 성분은 수분 함량 84.38 %, 조지방 0.94 %, 조단백 10.51 %, 조회분 3.51 %로 나타났다. 산 처리를 위해 1M 아세트산 (Acetic-CWPG), 0.5 M 아스코르브산 (Ascorbic-CWPG), 0.5 M 시트르산 (Citric-CWPG), 0.5 M 옥살산 (Oxalic-CWPG) 및 0.2 M 염산 (HCl - CWPG)이 사용되었으며, control은 증류수를 사용하였다. 상압 산처리의 경우 CWPG 건조중량의 10 배에 상당하는 산 용액을 첨가하여 산양삼과 함께 분쇄한 후 산 처리 반응은 실온에서 15 분간 반응시켰으며, 초고압 처리의 경우 분쇄한 산-산양삼 시료를 파우치에 넣고 밀봉한 후 상온에서 15분간 초고압 처리를 진행하였다. 두 시료 모두 반응이 끝난 후 2 M NaOH를 사용하여 pH 4.75로 중화시켰다. 추출은 70 % 에탄올을 사용하여 수행하였다 Ginsenoside profile 및 함량은 high performance liquid chromatography (HPLC)를 사용하여 분석되었다. 처리 시료의 항산화능을 측정하기 위해 Total phenolic contents, Total flavonoid content’s 및 DPPH radical 소거능을 측정하였다. 상압에서 처리된 산양삼의 경우 산의 종류에 관계없이 Ginsenoside profile에 특별한 변화가 나타나지 않았다. 550MPa에서 처리된 시료의 경우 acetic acid와 citric acid로 처리된 산양삼은 control과 비슷한 profile을 나타낸 반면 HCl과 oxalic acid로 처리된 산양삼은 major ginsenoside가 급격히 감소하였다. 초고압-산 처리가 major ginsenoside를 가수분해하여 minor ginsenoside 형성하는 것으로 생각된다. 상압에서 산 처리된 시료들은 TP 및 DPPH radical 소거능이 증가하는 경향성을 보였다. 하지만 홍삼 처리와 같은 가열처리에 비해 그 변화가 매우 미미하였다. TF의 경우 감소하는 경향을 나타냈다. 초고압-산 처리의 경우 상압처리와 비슷한 경향성을 나타냈지만 전체적으로 낮은 함량 및 활성을 나타냈다. 산양삼의 상압 및 초고압 산 처리를 통한 유효성분의 증대는 산양삼을 이용한 고부가가치 식품의 국내 및 세계 시장을 개척 및 확대하기 위하여 본 연구의 진행이 중요한 역할을 할 것으로 기대된다.

Molybdenum (Mo) is one of the representative refractory metals for its high melting point, superior thermal conductivity, low density and low thermal expansion coefficient. However, due to its high melting point, it is necessary for Mo products to be fabricated at a high sintering temperature of over 1800-2000 oC. Because this process is expensive and inefficient, studies to improve sintering property of Mo have been researched actively. In this study, we fabricated Mo nanopowders to lower the sintering temperature of Mo and tried to consolidate the Mo nanopowders through ultra high pressure compaction. We first fabricated Mo nanopowders by a mechano-chemical process to increase the specific surface area of the Mo powders. This process includes a high-energy ball milling step and a reduction step in a hydrogen atmosphere. We compacted the Mo nanopowders with ultra high pressure by magnetic pulsed compaction (MPC) before pressureless sintering. Through this process, we were able to improve the green density of the Mo compacts by more than 20% and fabricate a high density Mo sintered body with more than a 95 % sintered density at relatively low temperature.

The objective of this study was to investigate the non-thermal sterilization effect of methods such as high hydrostatic pressure (HHP) and UV-irradiation (specifically with regard to the storage stability and shelf-life of carrot juice. The microbial counts of the non-sterilized product increased from 5.51 to 7.34 log CFU/mL up to the fifth day, and then decreased to 5.46 log CFU/mL at six days. UV-irradiation was increased from 2.37 to 4.92 log CFU/mL. HHP was maintained under the 3 log CFU/mL. The pH of UV-irradiation and HHP was maintained withing the range of 6.29~6.30 and 6.20~6.22 during storage. However, the pH arising from non-sterilization decreased from 6.31 to 4.49. The color of non-sterilization changed significantly during storage, but UV-irradiation and HHP were similar during storage. The β- carotene content of non-sterilization was noted to have decreased from 269.45 to 65.19 μg/mL during storage. The UV- irradiation and HHP decreased from 263.46 and 268.35~281.16 μg/mL to 243.42 and 244.09~269.29 μg/mL, respectively. In conclusion, these findings suggest that HHP can be used for the pasteurization, or sterilization, of carrot juice and the optimal condition is two minutes.

스스로 분해될 수 있는 응집제는 물의 오염을 줄일 수 있어 큰 관심을 받고 있고 양성전분은 스스로 분해될 수 있는 좋은 응집제 중 하나이다. 양성전분은 전분 내 양전하를 띠기 때문에 음전하를 띠는 폐수에서 쉽게 응집역할을 할 수 있다. 양성전분의 제조는 일반적인 방법과 초고압을 이용한 방법, 초고압으로 만든 무정형입자전분(amorphous granular starch, AGS)을 이용한 방법을 사용하였으며, 이들의 물리 화학적 성질을 연구하였다. 일반적인 방법은 옥수 수전분과 양성화 시약인 (3-Chloro-2-hydroxypropyl)-trimethylammonium chloride (CHPTAC)를 40oC에서 24시간동안 반응을 시켰으며, 초고압을 이용한 방법은 같은 방법으로 550MPa 에서 30분동안 반응시켰다. 무정형입자전분을 이 용한 방법은 먼저 초고압을 이용해 제조한 무정형입자전분을 일반적인 방법과 동일하게 반응시켰다. 각각의 방법으 로 제조한 양성전분에 CHPTAC가 성공적으로 치환되었는지 확인하기 위해 질소함량, FT-IR, NMR 분석실험을 하여 성공적으로 치환된 것을 확인하였다. 결정화도를 확인하기 위해서 XRD실험을 진행한 결과, 일반적인 방법과 초고압 처리를 한 방법에서는 결정성이 약간 남아있었지만 무정형입자전분을 이용한 방법에서는 결정성이 완전히 소실된 것을 확인할 수 있었다. 현미경과 SEM을 이용하여 전분의 입자의 형태를 확인한 결과, 일반적인 방법과 초고압을 이용한 방법 및 무정형입자전분을 이용한 방법 모두에서 전분 입자의 형태에 큰 영향을 미치지 않았음을 확인 할 수 있어 양성화 반응은 전분입자의 형태에는 큰 영향을 미치지 않는다는 것을 확인할 수 있었다. DSC를 이용한 열 적 특성 분석결과에서는 양성화 반응이 옥수수전분의 열적 특성에 영향을 미치는 것을 확인 할 수 있었다. Kaolin을 이용한 양성화 전분의 응집력 실험 결과 모든 양성화 전분은 농도가 증가할수록 응집력이 증가하는 결과를 나타내 었고, 침전시간이 증가함에 따라 응집력이 증가하는 경향을 나타내었다. 이러한 결과를 통해 일반적인 방법과 초고 압을 이용한 방법으로 제조한 양성전분은 무정형입자전분을 이용하여 제조한 양성전분과 구별되는 물리화학적 성질 을 가지는 것을 확인 할 수 있었다. 비록 본 연구에서 제조한 양성전분들은 상업적으로 유통되고 있는 응집제에 비 해서는 낮은 응집력을 나타냈지만 자연적으로 분해가 될 수 있다는 장점을 가지고 있고, 새로운 형태의 양성전분을 제조할 수 있는 기반을 제공하여 전분의 활용가능성을 높여줄 수 있는 연구결과로 판단된다.

Effects of dynamic high-pressure (DHP) treatments with and without integration with heating on microbial stability, vitamin C concentration, color, sugar content, and pH of orange juice were studied and compared with those of the conventional thermal treatment. Freshly squeezed orange juice was heated at 90oC for 1 min or DHP-treated at 205 MPa and 20, 50, 60, or 70oC. The DHP treatment at 20oC without heating and the treatment at 50oC inactivated indigenous mesophilic aerobic microorganisms in orange juice by 4.2 and >7 log CFU/mL, respectively. The DHPtreated juice exhibited brighter color and higher vitamin C concentration and sugar content than the thermally treated juice, regardless of integration with heating. The DHP-treated juice demonstrated brighter color and higher sugar contents than untreated juice and thermally treated juice during storage at 4oC for 63 days. The results have demonstrated the potential of applying DHP treatments to pasteurize orange juice with increasing brightness and sugar content of the juice.