• 한국수소및신에너지학회논문집
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• 제5권1호
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• pp.51-57
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• 1994

Compaction techniques of hydrogen storage alloy 'powders, to solve the problems due to disintegration during the cyclic hydriding and dehydriding, by using polytetrafluoroethylene (PTFE) and silicon sealant as a polymer binder were studied. Optimum conditions of compaction were as follows. Binder content, 10 % for PTFE and 5 % for silicon sealant ; particle size of alloy powders, $-25{\mu}m$ ; compacting pressure, $4ton/cm^2$. Compacts obtained were easily activated and had a good strength even after 30 cycles of hydriding and dehydriding. PTFE added compacts showed very good rate capability, however, in the silicon added compacts hydrogen absorption rate was somewhat slow because of higher elasticity and adhesiveness of the binder.

• Environmental Engineering Research
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• 제10권1호
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• pp.7-14
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• 2005

The feasibility of hydrogen production with a raw seed sludge through direct acclimation of feedstock was investigated at acidogenic stage, and methane was harvested at followed methanogenic stage in an anaerobic two-stage process. Hydrogen content was higher than 57% at all tested organic loading rates (OLRs) and the yield of hydrogen ranged from 1.5 to 2.4 mol H2/mol hexose consumed and peaked at 6 gVSl-1day-1. Normal butyrate and acetate were main volatile fatty acids (VFAs), whereas the concentration of propionate was insignificant. The hydrogen-producing bacteria, Clostridium thermosaccharolyticum, was detected with strong intensity at all tested organic loading rates (OLRs) by denaturing gradient gel electrophoresis (DGGE) of the polymerase chain reaction (PCR) analysis. From COD balance in the process, the fraction of the feed-COD converted to the hydrogen-COD at acidogenic stage ranged from 7.9% to 9.3% and peaked at 6 gVSl-1day-1, whereas the fraction of feed-COD converted to the methane-COD at methanogenic stage ranged from 66.2% to 72.3% and peaked at 3 gVSl-1day-1.

• Journal of Microbiology
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• 제41권3호
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• pp.248-251
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• 2003

Glutathione (GSH) is an important factor in determining tolerance against oxidative stress in living organisms. It is synthesized in two sequential reactions catalyzed by ${\gamma}$-glutamylcysteine synthetase (GCS) and glutathione synthetase (GS) in the presence of ATP. In this work, the effects of three different oxidative stresses were examined on GSH content and GSH-related enzyme activities in the fission yeast Schizosaccharomyces pombe. GSH content in S. pombe was significantly enhanced by treatment with hydrogen peroxide, ${\beta}$-naphthoflavone (BNF) and tert-butylhydroquinone (BHQ). Simultaneously, they greatly induced GCS and GS activity. However, they did not have any effects on glutathione reductase activity. These results suggest that GCS and GS activities in S. pombe are up-regulated by oxidative stress.

• 한국수소및신에너지학회논문집
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• 제32권6호
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• pp.497-505
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• 2021

Water management is essential to improve the performance of proton exchange membrane fuel cells. This study targets to understand the characteristics of water concentration in proton exchange membrane fuel cells at a dynamic load variable environment. The fuel cell model was developed to simulate nonlinear water transport in membrane by the MATLAB/Simulink^® (MathWorks, Natick, MA, USA) platform, and it calculates water content in membrane, ionic conductivity, and predicts fuel cell performance through one-dimensional analysis.

• 한국수소및신에너지학회논문집
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• 제16권2호
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• pp.122-129
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• 2005

The characteristics of hydrogen storage have been investigated in the Ti-Cr-Mo and Ti-Cr-V ternary alloys with bcc structure. The alloys were melted by arc furnace and remelted 4-5 times for homogeneity. The lattice parameters, microstructures and phases of the alloys were examined by SEM, EDX and XRD, and the Pressure-Composition isotherms of the alloys were measured. From these data the relationship of the maximum and effective hydrogen storage capacities vs. chemical composition, lattice parameter and the radius of tetrahedral site were analyzed and discussed. The results showed that all of these alloy, in the range of the this study, had mainly bcc solid solutions with small amount of Ti segregation due to a lower melting point of Ti compared with other elements. Lattice parameters of the alloys were very near to the atomic average values of lattice parameters of the constituent elements. It was also found that maximum hydrogen storage capacities of the Ti-Cr-Mo alloys increased with increasing Ti content and the radius of tetrahedral site but the effective hydrogen storage capacities decreased after showing the maximum. The hydrogen storage capacities of the Ti-Cr-V alloys were almost same even though the V contens were quite different from alloy to alloy and this could be attributed to the almost same Ti/Cr ratio of the alloys. The maximum effective hydrogen storage capacity of the Ti-Cr-Mo alloys was revealed at Ti content of about 40${\sim}$50 at% and radius of tetrahedral site of 0.43${\sim}$0.45 nm. The Ti-Cr-V alloys showed the hydrogen storage capacities of 3.0 wt% and effective hydrogen storage capacities of 1.5 wt%.

• 한국수소및신에너지학회논문집
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• 제22권4호
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• pp.465-473
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• 2011

To find the optimum mixing ratio of WGS catalyst with $CO_2$ absorbent for SEWGS process, water gas shift reaction tests were carried out in a fluidized bed reactor using commercial WGS catalyst and sand (as a substitute for $CO_2$ absorbent). WGS catalyst content, gas velocity, and steam/CO ratio were considered as experimental variables. CO conversion increased as the catalyst content increased during water gas shift reaction. Variations of the CO conversion with the catalyst content were small at low gas velocity. However, those variations increased at higher gas velocity. Within experimental range of this study, the optimum operating condition(steam/CO ratio=3, gas velocity = 0.03 m/s, catalyst content=10 wt.%) to get high CO conversion and $CO_2$ capture efficiency was confirmed. Moreover, long time water gas shift reaction tests up to 20 hours were carried out for two cases (catalyst content = 10 and 20 wt.%) and we could conclude that the WGS reactivity at those conditions was maintained up to 20 hours.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 학술논문집
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• pp.361-367
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• 2004

원전 주변 주민들의 $^3H$ 및 $^14C$ 섭취선량을 평가하는데 필요한 농작물중 $^3H$ 와 $^14C$농도를 계산하기 위하여 국내 4개 원전 주변 10개 지역에서 채취한 채소 및 과일류의 수분, 수소 및 탄소함량을 분석하였다. 조사 대상 농작물은 2001~2002년 보건복지부 국민건강ㆍ영양 조사결과에 근거하여 결정하였고, 그것들의 섭취량 백분율을 식품가중치로 취하여 그룹 대푯값을 산출하였다. 원전 주변 농작물 시료들의 수분, 수소 및 탄소함량을 분석한 결과, 곡류는 현재 원전의 주민피폭선량 평가코드인 K-DOSE60에 적용중인 값과 유사하게 나타났다. 무 등의 근채류는 현행 ODCM의 채소류보다 3.5배정도 높은 수소함량을 보였고, 엽채류 및 과일류의 수분, 수소 및 탄소함량이 현행 ODCM과 비교하여 약 0.7~1.3배정도의 값을 보였다.

• 공업화학
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• 제10권1호
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• pp.98-104
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• 1999

본 연구에서는 ECR플라즈마 화학증착법을 이용하여 반응기내 압력의 변화에 따라 수소화된 무정형 실리콘막을 증착하고 박막내 수소의 함량과 결합구조 및 전기적 특성을 조사하였다. 일반적인 CVD에 의해 제조된 a-Si:H막은 증착속도가 증가할수록 광감도는 감소하지만 ECR플라즈마의 경우 증착속도가 증가할수록 광감도가 향상되었다. 마이크로파 출력과 사일렌/수소 희석비, 반응기내 압력등이 동일한 실험 조건에서 증착시간에 따른 막의 두께는 선형적으로 증가하고 막내에 함유된 수소의 농도는 일정하지만, 반응시간이 짧은 경우 막내에 $SiH_2$결합이 SiH결합보다 많이 형성되어 광전도도를 저하시킬 수 있다. 반응기내 압력이 증가함에 따라 박막내에 SiH결합이 증가하여 광학 에너지 갭을 줄여 광전도도를 향상시킬 수 있었으나 암전도도의 증가로 광감도는 감소하였다. 따라서 양질의 박막을 얻기 위해서는 압력이 낮고 수소기체의 양이 적은 조건에서 성장시켜야 한다.

• 한국초지조사료학회지
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• 제43권1호
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• pp.56-61
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• 2023

The germination process is critical for plant growth and development and it is largely affected by environmental stress, especially salinity. Recently, hydrogen sulfide (H₂S) is well known to act as a signaling molecule in a defense mechanism against stress conditions but poorly understood regulating seed germination. In this study, the effects of NaHS (the H₂S donor) pretreatment on various biochemical (hydrogen peroxide (H₂O₂) content and amylase and protease activity) and physiological properties (germination rate) during seed germination of oilseed rape (Brassica napus L. cv. Mosa) were examined under salt stress. The seed germination and seedling growth of oilseed rape were inhibited by NaCl treatment but it was alleviated by NaHS pretreatment. The NaCl treatment increased H₂O₂ content leading to oxidative stress, but NaHS pre-treatments maintained much lower levels of H₂O₂ in germinating seeds under salt stress. Amylase activity, a starch degradation enzyme, significantly increased over 2-fold in control, NaHS pretreatment, and NaHS pretreatment under NaCl during seed germination compared to NaCl treatment. Protease activity was highly induced in NaHS-pretreated seeds compared to NaCl treatment, accompanied by a decrease in protein content. These results indicate that NaHS pretreatment could improve seed germination under salt stress conditions by decreasing H₂O₂ accumulation and activating the degradation of protein and starch to support seedling growth.

• 한국수소및신에너지학회논문집
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• 제34권5호
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• pp.421-430
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• 2023

Fe-Ni-Pt nanocatalysts were loaded on carbon black powders which were synthesized by a spontaneous reduction reaction of iron (II) acetylacetonate, nickel (II) acetylacetonate and platinum (II) acetylacetonate. The morphology and the loading weight of Fe-Ni-Pt nanoparticles were characterized by transmission electron microscopy and thermogravimetric analyzer. The amount of Fe-Ni-Pt catalyst supported on the carbon black surface was about 6.42-9.28 wt%, and the higher the Fe content and the lower the Pt content, the higher the total amount of the metal catalyst supported. The Brunauer-Emmett-Teller Analysis (BET) specific surface area of carbon black itself without metal nanoparticles supported was 233.9 m²/g, and when metal nanoparticles were introduced, the specific surface area value was greatly reduced. This is because the metal nanocatalyst particles block the pore entrance of the carbon black, and thereby the catalytic activity of the metal catalysts generated inside the pores is reduced. From the I-V curves, as the content of the Pt nanocatalyst increased, the electrolytic properties of water increased, and the activity of the metal nanocatalyst was in the order of Pt > Ni > Fe.