• Clinical and Experimental Reproductive Medicine
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• 제46권4호
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• pp.189-196
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• 2019

Objective: We aimed to evaluate the effects of different oxygen conditions (20% [high O₂], 5% [low O₂] and 5% decreased to 2% [dynamic O₂]) on mouse pre- and peri-implantation development using a novel double-channel gas supply (DCGS) incubator (CNC Biotech Inc.) to alter the oxygen concentration during in vitro culture. Methods: The high-O₂ and low-O₂ groups were cultured from the one-cell to the blastocyst stage under 20% and 5% oxygen concentrations, respectively. In the dynamic-O₂ group, mouse embryos were cultured from the one-cell to the morula stage under 5% O₂ for 3 days, followed by culture under 2% O₂ to the blastocyst stage. To evaluate peri-implantation development, the blastocysts from the three groups were individually transferred to a fibronectin-coated dish and cultured to the outgrowth stage in droplets. Results: The blastocyst formation rate was significantly higher in the low-O₂ and dynamic-O₂ groups than in the high-O₂ group. The total cell number was significantly higher in the dynamic-O₂ group than in the low-O₂ and high-O₂ groups. Additionally, the apoptotic index was significantly lower in the low-O₂ and dynamic-O₂ groups than in the high-O₂ group. The trophoblast outgrowth rate and spread area were significantly higher in the low-O₂ and dynamic-O₂ groups than in the high-O₂ group. Conclusion: Our results showed that a dynamic oxygen concentration (decreasing from 5% to 2%) had beneficial effects on mouse pre- and peri-implantation development. Optimized, dynamic changing of oxygen concentrations using the novel DCGS incubator could improve the developmental competence of in vitro cultured embryos in a human in vitro fertilization and embryo transfer program.

• 한국수소및신에너지학회논문집
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• 제8권2호
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• pp.79-90
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• 1997

Extensive work has been done on investigating the inner cell pressure characteristics of sealed type Ni-MH battery in which Zr-Ti-Mn-V-Ni alloy is used as anode. The inner cell pressure of this type Ni-MH battery much more increases with the charge/discharge cycling than that of the other type Ni-MH battery where commercialized $AB_5$ type alloy is used as anode. The increase of inner cell pressure in the sealed type Ni/MH battery using Zr-Ti-Mn-V-Ni alloy system is mainly due to the accumulation of oxygen gas during charge/discharge cycling. The accumulation of oxygen gas arises mainly due to the low rate of oxygen recombination on the MH electrode surface during charge/discharge cycling. The difference of oxygen recombination rate between $AB_5$ type electrode and Zr-Ti-Mn-V-Ni electrode is caused by the difference of electrode reaction surface area resulting from different particle size after their activation and the difference of surface catalytic activity for oxygen recombination reaction, respectively. After EIS analysis, it is identified that the surface catalytic activity affects much more dominantly on the oxygen recombination reaction than the reaction surface area does. In order to suppress the inner cell pressure of Ni-MH battery where Zr-Ti-Mn-V-Ni is used as anode, it is suggested that the surface catalytic activity for oxygen recombination should be improved.

• 한국안전학회지
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• 제26권2호
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• pp.42-47
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• 2011

Going underwater is supposed to begin with the history of human beings. At first it was confined to relatively shallow level, less than several meters by holding breath. Recently, deep level diving has been necessary for such purpose as construction, maritime salvage, military operations, research and sports by using SCUBA(self-contained underwater breathing apparatus) equipment. As one goes down into water, the pressure on the diver is increased due to water pressure with depth, usually 1 atm for each 10 m water level. In deep water, mixed gas or nitrox(EAN, enriched air nitrox) could be applied for the divers lest they should get disease due to high pressure. Of these, the former is usually composed of oxygen and inert gas like helium or hydrogen, the latter contains higher oxygen content than that in normal air in which the oxygen concentration is designated by the character "EAN" followed by vol. % of oxygen, for example, "EAN 40" contains 40% of oxygen. In this case, a victim was found at the 39 m below the sea surface breathing air and nitrox in cylinder wrongly marked as EAN 36, which was analyzed to contain 63% of oxygen by GC/TCD. The cause of death could not be exactly related with the oxygen content in the nitrox cylinder, because the accurate depth for the victim to dive was not known, even though the victim was just found at the depth of 39 m. However, the wrongly marked nitrox could be believed to be the main cause of the death at the depth unless there happened any other accident except that during diving.

• 한국가스학회지
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• 제11권4호
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• pp.17-22
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• 2007

비예혼합 대향류화염에서 산소부화에 따른 NOx 생성특성에 관한 수치해석이 수행되었다. 순산소의 연소과정에서 공기침투에 의한 부득이한 질소 유입의 상황을 체계적으로 고려하기 위하여, 산화제의 $O_2$는 체적비 21%에서 100%까지 변화되었다. 결과적으로 NO 배출지수$(EI_{NO})$는 산소부화율 75%까지 증가하다가 급격히 감소하는 경향을 보여준다. 이러한 경향은 화염온도, 화염두께 및 체류시간 보다는 NOx 생성과 관련된 $N_2$ 소모율 변화에 의해 설명될 수 있음을 확인하였으며, 특히 N+NO=$N_2+O$ 반응이 가장 크게 기여함을 알 수 있었다.

• 공업화학
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• 제33권1호
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• pp.38-43
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• 2022

산소 플라즈마 처리에 따른 활성탄소의 산소 관능기 도입이 세슘 이온 흡착 특성에 미치는 영향에 대하여 고찰하였다. 산소 플라즈마 처리 시 주파수, 전력 및 산소 가스 유량은 각각 100 kHz, 80 W 및 60 sccm으로 고정하였으며, 반응시간을 변수로 수행하였다. 본 실험조건에서는 산소 가스와의 반응시간이 10분일 때 C-O-C 및 O=C-O 결합 내 산소 기능기 함량이 증가함에 따라 세슘 이온 흡착량이 증가하였다. 그러나 반응 시간이 15분일 때 산소 관능기 함량이 감소하게 되어 세슘 이온 흡착량이 오히려 감소되었다. 한편, 표면 처리된 활성탄소의 산소 함량과는 달리 그 비표면적 및 기공 특성은 산소 플라즈마 반응 시간에 따라 거의 영향을 받지 않았다. 결과적으로 산소 플라즈마 처리된 활성탄소는 미처리 활성탄소에 비하여 세슘 이온 제거율이 최대 97.3%까지 향상되었다. 이는 산소 플라즈마 처리로 활성탄소 표면에 도입된 C-O-C 및 O=C-O 결합 내 산소 기능기의 함량에 기인한 것으로 판단된다.

• 멤브레인
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• 제33권6호
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• pp.447-453
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• 2023

컴퓨터 시스템의 성능 및 다양한 전산모사 프로그램의 발전으로 더 복잡한 원소로 이루어진 화학시스템의 해석이 가능해지고, 그에 따라 분자동역학 전사모사를 활용한 연구가 활발히 이루어지고 있다. 특히, 기존에는 실험위주로 진행되던 고분자 막에 대한 기체 투과 특성을 계산하는 연구가 관심을 받고 있고, 식품포장, 의약품등에 사용되고 있는 기체차단성 막에 대한 분자동역학 연구가 많이 이루어지고 있다. 최근 실크 피브로인을 이용해 코팅막을 만들었을 때 기체 차단 효과가 나타난다는 보고가 있었고, 본 연구에서는 이러한 실크 피브로인을 활용해 복합막을 만들었을 때 산소 차단 효과가 나타나는지 확인하고자 분자동역학 전산모사를 이용해 연구를 진행하였다. 단일 모델을 제작하고 기체 투과 특성을 계산하고 실험값과 비교를 통해 모델이 실제 실험 결과를 반영하는 것을 확인하였고, 실제 복합막 모델을 만들어 고분자 내에서 기체 이동경로 분석을 진행한 결과 산소 분자가 피브로인 영역을 통과하지 못하고 막히는 것을 보여주었다. 따라서, 실크 피브로인이 도입된 복합막이 산소 차단 성능이 우수하여, 식품포장 등에 유용할 것으로 기대된다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.819-822
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• 2001

In this study a fiber optic biosensor has been developed to on-line monitor the concentrations of oxygen and glucose. The oxygen concentrations in solution and gas phase monitored by the fiber optic sensor has been compared with those by a dissolved oxygen electrode and an IR-type $O_2$ analyzer. The fiber optic glucose sensor has been made by immobilizing glucose oxidase on the tip of the optic fiber and used to on-line monitor the concentration of glucose in a fermentation process.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1006-1011
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• 1991

In this paper, a neural network estimator which estimates the output of the wide range oxygen sensor is proposed, The neural network estimator is constructed to give the output of the wide range oxygen sensor from rpm, fuel injection time, throttle position, and output voltage of the exhaust gas oxygen sensor. And, using this estimator, PI controller for air-fuel ratio control is designed. Experiment results show that the proposed method gives good results for SONATA engine under light load and constant rpms.

• Journal of Astronomy and Space Sciences
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• 제7권1호
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• pp.1-10
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• 1990

The thermodynamic distribution of the vibrational states of ozone coupled with anharmonic predissociation produces an unusual isotopomeric pattern of oxygen molecules. The model presented here explains the experimental data obtained from the electric discharge of oxygen gas to produce ozone condensed on a quartz at 77K.

• 한국주조공학회지
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• 제15권2호
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• pp.175-183
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• 1995

It is difficult to remove such interstitial impurities as sulfur, oxygen, hydrogen and carbon in Fe-Ni alloys. Thermodynamic and kinetic studies were carried out on the behavior of hydrogen gas, oxygen gas, Si, Al and slag, and the reaction time by the $Ar/Ar-H_2$ plasma and electron beam melting. After the addition of Al, Si, they were melted by Ar plasma with reaction time changed. 80%Ni-Fe alloys showed a better deoxidation than 36%Ni-Fe alloys. At $Ar-H_2$ plasma melting, the deoxidation was significant. In the case of the electron beam melting, the residual oxygen was higher than in Ar plasma melting because electron beam melting temperature was lower than that of Ar plasma. For the decaburization, it was melted by $Ar-O_2$ plasma melting, which could remove effectively carbon by activated oxygen in plasma. We added slag to Fe-Ni alloys for the desulfurization. As the result of this experiments, the amount of residual sulfur was not changed according to the slag ratio and reaction time.