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.

The objectives of this study were to characterize the physicochemical properties of ginger (Zingiber officinale Rosc.) and the optimum extract processing condition to increase the solubilization efficiency of 6-gingerol and polysaccharides disintegration. The physicochemical properties were investigated under high-pressure enzyme (HP) and enzyme (WB) treatment conditions such as reaction time (1, 2, 3 h), pressure (50, 70, 100 MPa) and sample types, and cell wall degradation enzyme (hemicellulase, cellulase, pectinase, glucosidase, etc.) The effect of high-pressure enzyme treatment depending on sample types was significantly highest in the freeze-dried ginger powder. The optimum condition for high-pressure enzyme treatment was with Pectinex Ultra SP-L (Pec) enzymes for 2 h at 50oC and 100 MPa. Water soluble indexes increased 4.6 and 3.8 times more compared to CON (15.35%) while total polyphenol contents increased by 1.8 and 1.7 times compared to CON (1.43%). The total contents of indicator components such as 6, 8, 10-gingerol and shogaol was 1.53%, increasing 2.7 times more compared to CON (0.57%) with a significant difference (p<0.001). The high-pressure and enzymatic approach described in this study would be beneficial to food industries for developing ginger functional product and materials.

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.

본 연구는 홍삼 유화 음료의 유통기한 예측을 위하여 수행하였다. 저장기간 동안 이화학적 특성 (산도, pH, 지방구크기, 색도) 및 관능적 특성의 변화를 주기적으로 조사하였다. 저장 초기에 홍삼 유화 음료의 산도, pH 및 지방구 크기는 거의 변화하지 않았으나 저장 후반기(70일 이후)에는 유의적으로 변화하 였으며 이는 주로 Maillard reaction 의한 것으로 추정하였다. 관능특성과 이화학적 특성들과의 상관분석을 통하여 색도 a 값(적색도)을 홍삼 유화 음료의 이화학적 품질지표로 설정하였다. Arrhenius 식에 의한 a값 변화에 대한 활성화 에너지 및 Q10-value는 각각 13.37 kcal/mol, 1.56-2.14로 조사되었으며, 홍삼 유화 음료의 유통기한은 상온(20℃) 보관의 경우 730일(약 2년)로 예측되었다.

We investigated the influence of germination and high hydrostatic pressure (HHP) treatment conditions on the conversion of functional compounds and antioxidant activity in adzuki bean. The adzuki bean germinated at 25°C for three- or six-days, and was later subjected to HHP at 0.1, 50, 100, or 150 MPa for 24 h. The highest polyphenol content (5.36 mg gallic acid equivalents (GAE)/g) and flavonoid content (0.91 mg catechin equivalents (CE)/g) were observed after germination for six days and HHP treatment at 100 MPa for 24 h, respectively. The total phenolic acid contents increased with increasing applied pressure from 88.86 to 208.26 μg/g (100MPa, 24h). Phenolic acids are divided into two categories; those that exhibit increased content upon HHP treatment, and those that exhibit decreased content. The increasing phenolic acids were gallic acid, chlorogenic acid, (+)-catechin, ρ-coumaric acid, ferulic acid, heperidin, salicylic acid, protocatechuic acid, cinnamic acid, naringenin. The total anthocyanin content decreased with increasing applied pressure from 22.42 mg/100 g to 6.28 mg/100 g (150 MPa, 24 h). The highest ABTS radical scavenging activity (8.02 mg eq AA/g) and DPPH radical scavenging activity (1.22 eq Trolox/g) were observed after germination for six days and HHP treatment at 100MPa for 24h, respectively. These results suggested that the combination of HHP and germination can lead to improved functionality in adzuki bean.

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.

In this study, two Fe-30Mn-0.2C-(1.5Al) high-manganese steels with different surface conditions were hydrogencharged under high temperature and pressure; then, tensile testing was performed at room temperature in air. The yield strength of the 30Mn-0.2C specimen increased with decreasing surface roughness(achieved via polishing), but that of the 30Mn-0.2C- 1.5Al specimen was hardly affected by the surface conditions. On the other hand, the tendency of hydrogen embrittlement of the two high-manganese steels was not sensitive to hydrogen charging or surface conditions from the standpoints of elongation and fracture behavior. Based on the EBSD analysis results, the small decrease in elongation of the charged specimens for the Fe-30Mn-0.2C-(1.5Al) high-manganese steels was attributed to the enhanced dislocation pile-up around grain boundaries, caused by hydrogen

Cutting tools tend to wear gradually with progressing of machining process due to extremely high surface loads and temperature from the relative motions between tool and workpiece. Especially, the high cutting temperature is a dominant factor in the relation to tool life. High-pressure coolant has been reported as an effective method to prevent the severe wear from cutting temperature. This research investigates efficient supplying conditions of high-pressure coolant with the CFD results from a internal-flush drilling process. The flow rate of coolant is increased drastically up to three times under 70 bar compared to conventional way.

In this study, FLUENT v.16.1 was used to investigate the compressible flow generated by the supersonic jet spewed from a high pressure tube. As the boundary condition for CFD (Computational Fluid Dynamics) analysis, the inlet temperature of air was constantly 300 K and the variation of JPR (Jet Pressure Ratio) were 5, 50, 100, 150 and the variation of tube diameter were 10, 20, 30 cm. As a result, it was confirmed that the effective range was increased as the JPR was higher, but it was confirmed that the effective range was lower than the JPR rise, and that the effective range was increased as the diameter was larger. Therefore, it is found that the tube diameter is more sensitive than the JPR among the influence factors of jet, and if the result of this study were reflected in the design of high pressure system, it will contribute to the design of the system for preventing the second accident.

Medium pressure and mixed enzyme were used to hydrolyze raw anchovy under controlled conditions at a batchpilot plant-scale process for the production of anchovy protein hydrolysates (APH). Mass balance calculations were carried out so that the degree of protein solubilization and yields could be estimated. Almost complete hydrolysis could be achieved in 12 h, at 50oC and 75 MPa, with no pH adjustment, at 1% (10 g/kg) mixed enzyme using raw anchovy. This was achieved with the addition of water (1/2 raw anchovy/water). The degrees of protein solubilization and yield were 63.50% and 55.61%, respectively. Fractionation using UF/NF pilot scale systems was carried out for producing four different fractions on the APH. Successive fractionation on UF and NF membranes allowed the concentration of the peptides of selected sizes without, however, carrying out sharp separations, and with some MW classes being found in several fractions. Spray drying processes for 10 kDa permeate were described to increase their usability. The free amino acid profile of the fractions was identical to that of the APH.

A Taguchi robust design method with an L9 orthogonal array and larger-the-better characteristics was implemented to optimize experimental conditions for the hydrolysis of raw anchovy using a pressure-assisted enzymatic reaction method. The degree of hydrolysis (DH), nitrogen recovery (NR) and yield were considered as the response parameters. Pressure, reaction temperature, reaction time, and mixed enzyme amount were chosen as control parameters. As a result of the Taguchi analysis in this study, the pressure was found to be the most influential parameter on DH and NR. The amount of mixed enzyme in the reaction also had a significant effect on DH and NR. Meanwhile, the optimum values were confirmed to be similar at 95% confidence and 5% significance level through analysis of variance (ANOVA). Furthermore, new hydrolysates at optimum conditions and control hydrolysates at atmospheric pressure were compared in terms of the DH, resulting in the improvement of DH by more than 52.6%.

In this study, ultra-fine soft-magnetic micro-powders are prepared by high-pressure gas atomization of an Fe-based alloy, Fe-Hf-B-Nb-P-C. Spherical powders are successfully obtained by disintegration of the alloy melts under high-pressure He or N2 gas. The mean particle diameter of the obtained powders is 25.7 μm and 42.1 μm for He and N2 gas, respectively. Their crystallographic structure is confirmed to be amorphous throughout the interior when the particle diameter is less than 45 μm. The prepared powders show excellent soft magnetic properties with a saturation magnetization of 164.5 emu/g and a coercivity of 9.0 Oe. Finally, a toroidal core is fabricated for measuring the magnetic permeability, and a μr of up to 78.5 is obtained. It is strongly believed that soft magnetic powders prepared by gas atomization will be beneficial in the fabrication of high-performance devices, including inductors and motors.

This study investigates the thermal shock property of a polycrystalline diamond compact (PDC) produced by a high-pressure, high-temperature (HPHT) sintering process. Three kinds of PDCs are manufactured by the HPHT sintering process using different particle sizes of the initial diamond powders: 8-16 μm (D50 = 4.3 μm), 10-20 μm (D50 = 6.92 μm), and 12-22 μm (D50 = 8.94 μm). The microstructure observation results for the manufactured PDCs reveal that elemental Co and W are present along the interface of the diamond particles. The fractions of Co and WC in the PDC increase as the initial particle size decreases. The manufactured PDCs are subjected to thermal shock tests at two temperatures of 780oC and 830oC. The results reveal that the PDC with a smaller particle size of diamond easily produces microscale thermal cracks. This is mainly because of the abundant presence of Co and WC phases along the diamond interface and the easy formation of Co-based (CoO, Co3O4) and W-based (WO2) oxides in the PDC using smaller diamond particles. The microstructural factors for controlling the thermal shock property of PDC material are also discussed.