HyPer is the genetically encoded biosensor of intracellular hydrogen peroxide (H2O2), the most stable of the reactive oxygen species (ROS) generated by living cells. HyPer has a high sensitivity and specificity for detecting intracellular H2O2 by confocal laser microscopy. However, it was not known whether high speed ratiometric imaging of H2O2 by HyPer is possible. We thus investigated the sensitivity of HyPer in detecting changes to the intracellular H2O2 levels in HEK293 and PC12 cells using a microfluorometer imaging system. Increase in the HyPer ratio were clearly evident on stimulations of more than 100 μM H2O2 and fast changes in the HyPer ratio were observed on ratiometric fluorescent images after H2O2 treatment. These results suggest that HyPer is a potent biosensor of the fast temporal production of intracellular H2O2.

A 90 wt% Mg-10 wt% NbF5 sample was prepared by mechanical milling under H2 (reactive mechanical grinding). Its hydriding and dehydriding properties were then examined. Activation of the 90 wt% Mg-10 wt% NbF5 sample was not required. At n=1, the sample absorbed 3.11 wt% H for 2.5 min, 3.55 wt% H for 5 min, 3.86 wt% H for 10 min, and 4.23 wt% H for 30 min at 593K under 12 bar H2. At n=1, the sample desorbed 0.17 wt% H for 5 min, 0.74 wt% H for 10 min, 2.03 wt% H for 30 min, and 2.81 wt% H for 60 min at 593K under 1.0 bar H2. The XRD pattern of the 90 wt% Mg-10 wt% NbF5 after reactive mechanical grinding showed Mg, β-MgH2 and small amounts of γ-MgH2, NbH2, MgF2 and NbF3. The XRD pattern of the 90 wt% Mg-10 wt% NbF5 dehydrided at n=3 revealed Mg, β-MgH2, a small amount of MgO and very small amounts of MgH2 and NbH2. The 90 wt% Mg-10 wt% NbF5 had a higher initial hydriding rate and a larger quantity of hydrogen absorbed for 60 min than the 90 wt% Mg-10 wt% MnO and the 90 wt% Mg-10 wt% Fe2O3, which were reported to have quite high hydriding rates and/or dehydriding rates. The 90 wt% Mg-10 wt% NbF5 had a higher initial dehydriding rate (after an incubation period) and a larger quantity of hydrogen desorbed for 60 min than the 90 wt% Mg-10 wt% MnO and the 90 wt% Mg-10 wt% Fe2O3.

Hydrogen has the very high heating value by comparing with other fuels and its combustion exhausts no carbon. But hydrogen causes the very high adiabatic flame temperature which generates thermal NOx. In this study, two cases of experiments were performed to compare engine characteristics. First and second cases are for only diesel combustion engine and mixed hydrogen diesel engine respectively. To verify the effect of mixed hydrogen-diesel combustion engine, the exhausted gas from modified dual fuel diesel engine was analyzed. In addition, diesel consumption per kWh for each case was estimated to validate its economic feasibility. By mixing hydrogen with 5kW brown(hydrogen-oxygen mixture) gas generator, the amount of CO(carbon mono-oxide) decreased from 330ppm to 210ppm by improving combustion and the amount of NOx increased from 390ppm to 520ppm by higher temperature of combustion chamber. Diesel consumption per kWh decreased from 450cc to 410cc but actually increased until 480cc because of the power of brown gas generator

There are estimated to be about 700 species of bacteria in the oral cavity. Based on epidemiological investigations, some of these strains have been proposed as the pathogens responsible for oral diseases such as dental caries, gingivitis and periodontitis. Since electrolyzed hydrogen-rich water has been shown to have beneficial effects on human im- munity, its use has increased. In our study, the antibacterial activity of hydrogen-rich water for oralagainst bacteria asso- ciated with oral disease was evaluated. The bacterial strains Streptococcus mutans, Fusobacterium nucleatum, Porphy- romonas gingivalis and Tannerella forsythia were cultured in specific growth medium. S. mutans, F. nucleatum and P. gingivalis were soaked to thein both hydrogen water and tap water for 30 sec and then inoculated onto mitis-sali- varius agar and brain heart infusion agar including supple- mented withvitamin K and hemin, respectively. The num- bers of bacterial colonies were then measured after cultiva- tion for 48 hours. In the case of T. forsythia, which does not grow well on agar plates, inoculations into modified new oral spirochete (NOS) broth were performed and growth curve analysis was undertaken every day with a spectrophotometer. Hydrogen water showed antibacterial activity against all four bacterial strains in comparison with tap-water. We conclude from this that hydrogen water may have a positive impact on oral hygiene by helping to remove cariogenic bacteria and periodontopathogens.

The study on the fabrication of iron powder from forging scales using hydrogen gas has been conducted on the effect of hydrogen partial pressure, temperature, and reactive time. The mechanism for the reduction of iron oxides was proposed with various steps, and it was found that reduction pattern might be different depending on tem- perature. The iron content in the scale and reduction ratio of oxygen were both increased with increasing reactive time at 0.1atm of hydrogen partial pressure. On the other hand, for over 30 minutes at 0.5 atm of hydrogen partial pressure, the values were found to be almost same. In the long run, iron metallic powder was obtained with over 90% of iron content and an average size of its powder was observed to be about 100 µm.

The hydrogen storage properties of pure MgH2 were studied and compared with those of pure Mg. At the first cycle,pure MgH2 absorbed hydrogen very slowly at 573 K under 12 bar H2. The activation of pure MgH2 was completed after threehydriding-dehydriding cycles. At the 4th cycle, the pure MgH2 absorbed 1.55wt% H for 5 min, 2.04wt% H for 10 min, and3.59wt% H for 60 min, showing that the activated MgH2 had a much higher initial hydriding rate and much larger Ha (60min), quantity of hydrogen absorbed for 60 min, than did activated pure Mg. The activated pure Mg, whose activation wascompleted after four hydriding-dehydriding cycles, absorbed 0.80wt% H for 5 min, 1.25wt% H for 10 min, and 2.34wt%H for 60 min. The particle sizes of the MgH2 were much smaller than those of the pure Mg before and after hydriding-dehydriding cycling. The pure Mg had larger hydrogen quantities absorbed at 573K under 12 bar H2 for 60 min, Ha (60 min),than did the pure MgH2 from the number of cycles n=1 to n=3; however, the pure MgH2 had larger Ha (60 min) than didthe pure Mg from n=4 to n=6.

Though hydrogen peroxide (H₂O₂) causes a deleterious effect to cells with its reactive oxygen species resulting in cell death, S-allyl cysteine (SAC, a bioactive organosulfur compound of aged garlic extract) has been known to have a cytoprotective effect. Few reported profiles of gene expression of H₂O₂ and SAC treated human cord blood derived mesenchymal stem cells (MSC). This study revealed changes in the profile of twenty-one genes grouped by oxidative stress, antioxidant, cell death, anti-apoptosis and anti-aging by quantitative real time PCR. A concentration of 100μM of SAC or 50μM of H₂O₂ was applied to MSC which show moderate growth and apoptosis pattern. H₂O₂ treatment enhanced expression of eleven genes out of twenty-one genes compared with that of control group, on the contrary SAC suppressed expression of eighteen genes out of twenty-one genes except C ros oncogene. SAC decreased expression of oxidative stress genes such as SOD1, CAT and GPX. These results seemed consistent with reports which elucidated over expression of NF-kB by H2O2, and suppression of it by SAC. This study will confer basic information for further experiments regarding the effects of SAC on gene levels.

In order to fabricate the porous Mo with controlled pore characteristics, unique processing by using powder as the source and camphene as the sublimable material is introduced. Camphene-based 15 vol% slurries, prepared by milling at with a small amount of dispersant, were frozen at . Pores were generated subsequently by sublimation of the camphene during drying in air for 48 h. The green body was hydrogen-reduced at , and sintered at for 1 h. After heat treatment in hydrogen atmosphere, powders were completely converted to metallic W without any reaction phases. The sintered samples showed large pores with the size of about which were aligned parallel to the camphene growth direction. Also, the internal wall of large pores and near bottom part of specimen had relatively small pores due to the difference in the camphene growth rate during freezing process. The size of small pores was decreased with increase in sintering temperature, while that of large pores was unchanged. The results are strongly suggested that the porous metal with required pore characteristics can be successfully fabricated by freeze-drying process using metal oxide powders.

Carbon materials were synthesized by pyrolysis from fibers of Corn-straw (Zea mays), Rice-straw (Oryza sativa), Jute-straw (Corchorus capsularis) Bamboo (Bombax bambusa), Bagass (Saccharum officinarum), Cotton (Bombax malabaricum), and Coconut (Cocos nucifera); these materials were characterized by scanning electron microscope, X-ray diffraction (XRD), and Raman spectra. All carbon materials are micro sized with large pores or channel like morphology. The unique complex spongy, porous and channel like structure of Carbon shows a lot of similarity with the original anatomy of the plant fibers used as precursor. Waxy contents like tyloses and pits present on fiber tracheids that were seen in the inherent anatomy disappear after pyrolysis and only the carbon skeleton remained; XRD analysis shows that carbon shows the development of a (002) plane, with the exception of carbon obtained from bamboo, which shows a very crystalline character. Raman studies of all carbon materials showed the presence of G- and D-bands of almost equal intensities, suggesting the presence of graphitic carbon as well as a disordered graphitic structure. Carbon materials possessing lesser density, larger surface area, more graphitic with less of an sp3 carbon contribution, and having pore sizes around 10μm favor hydrogen adsorption. Carbon materials synthesized from bagass meet these requirements most effectively, followed by cotton fiber, which was more effective than the carbon synthesized from the other plant fibers.

본 연구의 목적은 강제환기가 적용되는 슬러리 돈사를 대상으로 돼지 생육 단계별 돈방 유형 측면과 계절적 조건에 따른 암모니아와 황화수소의 실내 농도를 측정 분석하여 정량화하는 데 있다. 임신/분만 돈방의 경우 봄철은 5.60(±2.48) ppm과 178.4(±204.8) ppb, 여름철은 2.51(±3.08) ppm과 86.6(±112.5) ppb, 가을철은 4.96(±2.84) ppm과 182.3(±242.6) ppb, 겨울철은 6.82(±3.42) ppm과 206.3(±356.8) ppb로, 자돈방의 경우 봄철은 7.18(±3.26) ppm과 486.0(±190.2) ppb, 여름철은 4.23(±2.95) ppm과 206.4(±186.9) ppb, 가을철은 7.02(±2.65) ppm과 465.4(±156.8) ppb, 겨울철 은 9.25(±3.68) ppm과 618.4(±298.3) ppb로, 육성/비육 돈방의 경우 봄철은 9.26(±3.02) ppm과 604.4(±186.8) ppb, 여름철은 6.78(±3.88) ppm과 312.5(±215.4) ppb, 가을철은 9.34(±2.14) ppm과 578.2(±248.1) ppb, 겨울철은 14.65(±3.15) ppm과 825.3(±316.9) ppb로 분석되었다. 측정 결과 암모니아와 황화수소 모두 돼지 생육 단계별 돈사 유형 측면에서는 육성/비육 돈사>자돈사>임신/분만 돈사의 순서로 나타났고(p<0.05), 계절적 측면에서는 겨울>봄>가을>여름 순서로 조사되었으나 봄철과 가을철 데이터 간의 차이는 통계적으로 입증되지 않았다(p>0.05).

Hydrogen is in the spotlight as an alternative next generation energy source for the replacement of fossil fuels because it has high specific energy density and emits almost no pollution, with zero CO2 emission. In order to use hydrogen safely, reliable storage and transportation methods are required. Recently, solid hydrogen storage systems using metal hydrides have been under extensive development for application to fuel cell vehicles and fuel cells of MCFC and SOFC. For the practical use of hydrogen on a commercial basis, hydrogen storage materials should satisfy several requirements such as 1) hydrogen storage capacity of more than 6.5wt.% H2, moderate hydrogen release temperature below 100˚C, 3) cyclic reversibility of hydrogen absorption/desorption, 4) non toxicity and low price. Among the candidate materials, Li based metal hydrides are known to be promising materials with high practical potential in view of the above requirements. This paper reviews the characteristics and recent R&D trends of Li based complex hydrides, Li-alanates, Li-borohydrides, and Li-amides/imides.

This study is about the qualitative safety assessment for hydrogen gas filling facilities in Korea operating with one-bank type. The purpose of this safety assessment is about the development of components for design, fabrication, assembly, operability of dispenser and systems of the safety. For the qualitative safety assessment method, the study used FMEA(failure mode & effect analysis) and HAZOP(hazard & operability). This study evaluated the safety through FMEA and HAZOP then by referring to P&ID and PFD of hydrogen dispenser, thereby examining the dangerousness of the equipments, defects of the structure and problems of the operation.

팔라듐이 코팅된 V99.8B0.2 합금 분리막을 통해 sweep 가스를 사용하지 않고 수소 투과 시 혼합가스의 영향에 대해 알아보았다. 분리막은 400℃에서 sweep 가스를 사용하지 않고 순수 수소, 수소/이산화탄소, 수소/일산화탄소의 혼합가스를 1.5~8.0 bar의 압력으로 실험하였다. Sweep 가스를 사용하지 않고 수소만을 공급한 투과 실험에서 팔라듐 코팅된 V99.8B0.2 합금 분리막(두께 : 0.5 mm)의 수소 투과량은 40.7mL/min/㎠였다. 또한 수소/이산화탄소를 공급한 투과실험에서 V99.8B0.2 합금 분리막의 수소 투과량은 21.4mL/min/㎠였다. 수소/이산화탄소 및 수소/일산화탄소 혼합가스를 각각 공급할 때 투과량은 압력에 상관없이 수소 분압 감소 만큼 감소하였고 모든 경우 Sievert 법칙을 잘 만족시켰다. 투과 후 분리막의 XRD, SEM/EDX 결과로부터 V99.8B0.2 합금 분리막은 여러 혼합가스에 대해 안정성과 내구성이 우수하다는 것을 알 수 있었다.

니오븀 금속을 기반으로 하는 Nb56Ti23Ni21 합금 분리막의 수소 투과 특성 및 화학적 안정성에 관한 연구를 수행하였다. 이를 위하여 직경 10 mm, 두께 0.5 mm의 Nb56Ti23Ni21 합금 분리막을 제작하였으며, 2가지 조성(H2 100%, H2 60% + CO2 40%)의 공급가스를 450℃의 온도에서 투과시킬 때 압력에 따른 수소 투과 특성에 관한 실험을 진행하였다. 본 실험에서의 최대 수소 투과량은 순수한 수소를 투과시킬 경우 절대압력 3 bar에서 5.58mL/min/cm2로 나타났다. 또한 공급가스 조성에 따른 각각의 경우 모두 Sievert's law에 잘 부합하였으며, 이산화탄소와의 혼합가스 사용시, 투과량은 수소 분압 감소에 비례하여 감소하였다. 투과 실험 후 XRD 분석을 통하여 Nb56Ti23Ni21 합금 분리막의 이산화탄소에 대한 화학적 안정성에 대한 실험을 수행하였다.

The hydrogen embrittlement of high strength steel for automobiles was evaluated by small punch (SP) test. The test specimens were fabricated to be 5 series, having various chemical compositions according to the processes of heat treatment and working. Hydrogen charging was electrochemically conducted for each specimen with varying of current density and charging time. It was shown that the SP energy and the maximum load decreased with increasing hydrogen charging time in every specimen. SEM investigation results for the hydrogen containing samples showed that the fracture behavior was a mixed fracture mode having 50% dimples and 50% cleavages. However, the fracture mode of specimens with charging hydrogen changed gradually to the brittle fracture mode, compared to the mode of other materials. All sizes and numbers of dimples decreased with increasing hydrogen charging time. These results indicate that hydrogen embrittlement is the major cause of fracture for high strength steels for automobiles; also, it is shown that the small punch test is a valuable test method for hydrogen embrittlement of high strength sheet steels for automobiles.

고온수증기전기분해(HTSE) 장치의 수소생산 및 열 화학적 특성을 파악하고자 COMSOL Multiphysics®를 사용해 2차원 정상상태 수치해석을 실시하였다. 계산을 위한 주요 파라메터로는 작동전압, ASR(Area-specific Resistance) 및 유입가스의 온도와 압력 등이다. 해석결과 1.2454 V에서 Thermal-neutral Voltage가 나타나고, 작동 전압이 증가함에 따라 Cell의 내부 온도가 단조 증가하는 것이 아니라 Thermal-neutral Voltage를 기준으로 낮은 전압에서는 Cell의 온도가 감소하고, 높은 전압에서는 Cell의 온도가 증가하였다. 또한, ASR 값이 증가함에 따라 Cell 내부의 온도는 하강하고, 수소생산율도 낮아지는 경향을 보였다.

보론이 도프된 바나듐 합금 분리막은 아직까지 연구된 적이 없다. 본 연구에서는 팔라듐이 코팅된 새로운 V99.8B0.2 조성의 합금 분리막을 합성하여 수소 투과 특성 및 화학적 안정성에 대하여 연구를 수행하였다. 순수 수소, 수소와 이산화탄소의 혼합가스를 400℃, 절대압력 1.0~3.0 bar에서 공급하여 수소 투과 특성을 알아보았다. 순수 수소를 공급하여 측정한 결과 0.5 mm 두께의 분리막은 최대 48.5mL/min/㎠의 투과량을 보였다. 본 연구 결과는 수성가스 전이반응(WGS)에서 생성된 수소를 분리할 수 있는 비 팔라듐계 수소 분리막의 합성에 새로운 방향을 제시하고 있다.

This study describes a hydrogen embrittlement evaluation of the subsurface zone in 590DP steel by micro-Vickers hardness measurement. The 590DP steel was designed to use in high-strength thin steel sheets as automotive materials. The test specimens were fabricated to 5 series varying the chemical composition through the process of casting and rolling. Electrochemical hydrogen charging was conducted on each specimen with varying current densities and charging times. The relationship between the embrittlement and hydrogen charging conditions was established by investigating the metallography. The micro-Vickers hardness was measured to evaluate the hydrogen embrittlement of the subsurface zone in addition to the microscopic investigation. The micro-Vickers hardness increased with the charging time at the surface. However, the changing ratio and maximum variation of hardness with depth were nearly the same value for each test specimen under the current density of 150 mA/cm2 and charging time of 50 hours. Consequently, it appears that hydrogen embrittlement in 590DP steel can be evaluated by micro-Vickers hardness measurement.