The purpose of this study is to develop a pH measurement system capable of measuring the acidity of saliva to check the change in pH level in saliva during driving and to detect whether fatigue is affected. When the pH level is checked at rest and operation, and oxygen concentration is supplied additionally, it will be verified whether the fatigue is reduced. It is reported that the pH level in saliva is divided into stages from 0 to 14, and the lower the value based on step 7, the higher the fatigue, and the lower the fatigue. In particular, in enclosed vehicles, drowsiness and fatigue due to increased carbon dioxide have increased, leading to a major cause of traffic accidents. Therefore, fatigue may be detected in advance by analyzing fatigue through a change in pH level by supplying oxygen during operation. The electromotive force generated by the existing itself is a level of several mV to develop a pH measurement system, so it is developed by expanding it to a range that can be measured using a readout circuit. In the experiment, 13 male experimenters in their 20s measured pH levels in resting and driving conditions. After 20 minutes of rest, the process of inhaling oxygen for 20 minutes was repeated three times. The oxygen concentration used in the experiment was 21% oxygen and 30% oxygen concentration in the atmospheric state, and in the oxygen supply method, a triangular flask was directly connected to the subject’s nose and then oxygen was supplied. As a result of collecting and analyzing saliva after rest and operation, it was confirmed that the pH level tended to decrease in the operating state. In addition, as a result of increasing the pH level when the oxygen concentration is 30% more than 21%, it is confirmed that fatigue tends to decrease as the oxygen concentration increases. Therefore, it was possible to confirm a significant change in fatigue by analyzing the pH level of saliva through this pH measurement system. This study can be used as a fatigue test in various environments through simple pH measurement.

본 연구에서는 진해만의 DO 농도 재현을 목표로 LSTM 모형의 최적 매개변수 조건과 예측변수를 선별하기 위한 Case study를 진행하였다. 모형 매개변수 Case study 결과, 가장 적은 Hidden node와 Epoch인 Hidden node=10, Epoch=100에서 가장 낮은 정확도를 보였다. 이는 모형이 과소적합(Underfitting) 상태인 것으로 판단된다. Hidden node=80, Epoch=1200에서 R2 값은 0.99로 가장 높은 정확도를 보였다. 예 측변수 Case study 결과, 1개의 환경변수만을 예측변수로 사용한 Step 1에서 수온을 예측변수로 했을 때 저층 DO 농도 재현의 R2 값은 0.81 로 가장 높은 정확도를 보였다. 이후 2개의 환경변수를 사용한 Step 2에서는 수온과 SiO2를 예측변수로 했을 때 R2 값은 0.92로 수온만 사 용했을 때보다 정확도가 급격히 증가하였다. 이는 저층 DO 농도와 SiO2 농도간의 높은 상관성(=0.70)에 기인한 것으로 판단된다. 상기 결과로부터 진해만의 DO 농도 재현에 적합한 LSTM 모형의 매개변수와 예측변수를 찾을 수 있었다.

In order to determine the location of average concentration and distribution status of dissolved oxygen in the rectangular aeration tank of the sewage treatment plant was analyzed and the difference of dissolved oxygen concentration was remarkable at each location. Compared with the computational fluid dynamics analysis, it was found that the results were consistent with the measurement results by showing the difference of dissolved oxygen concentration between the locations. Based on the measured data, the representative location of dissolved oxygen in aeration tank was selected by using statistical analysis method and the representative location was expressed in three-dimensional coordinates(LWH : 25%, 50%, 33%) from flow direction and left wall. Also the difference between the dissolved oxygen concentration at the actual measurement location and the average concentration value of the entire aeration tank was founded, and the equations for calibrating the automatic measurement data considering the actual measurement location were calculated.

Needle-like NiO protecting layers on NiCrAl alloy foam, used as support for hydrogen production, are introduced through electroplated Ni and subsequent microwave annealing. To improve the stability of the NiCrAl alloy foam, oxygen concentration of microwave annealing to form a needle-like NiO layer with good chemical stability and corrosion resistance is controlled in a range of 20 and 50 %. As the oxygen concentration increases to 50 %, needle-like NiO forms a dense coating layer on the NiCrAl alloy foam; this layer formation can be attributed to accelerated growth of the (200) plane. In addition, the increased oxygen concentration causes increased NiO/Ni ratio of the resultant coating layer on NiCrAl alloy foam due to improved rate of the oxidation reaction. As a result, the introduction of dense needle-like NiO layers formed at 50 % oxygen concentration improves the chemical stability of the NiCrAl alloy foam by protecting the direct electrochemical reaction between the electrolyte and the foam. Thus, needle-like NiO can be proposed as a superb protecting layer to improve the chemical stability of NiCrAl alloy form.

산소 분리를 위한 세라믹 중공사막을 상전이 방적기술을 통해 제조하였다. 초기 BSCF 선구물질은 고상반응법을 이용하여 합성한 상용 분말이며, 고분자 용액에 분산시킨 후 이중관형 노즐을 통해 사출하였다. 사출된 분리막은 상전이 과정을 거친 후 건조시켰으며 중공사막의 한쪽 끝을 밀봉하였다. 한쪽 끝이 막힌 중공사막의 표면에 dip coating 방법으로 LSCF를 코팅하였으며 1100 ℃에서 소결하여 치밀성을 갖는 한쪽 끝이 막힌 LSCF coated BSCF 중공사막을 제조하였다. 분리막의 공급측은 대기 중 공기를 사용하였으며 투과측은 진공상태를 유지하였다. 투과된 기체의 유량 및 산소의 농도를 측정하였으며 장기투과 실험과 EDS 분석을 통해 분리막의 안정성 평가를 진행하였다.

주요 엽채류 7종의 주년 안정생산을 위한 담액수경 재배 시 양액의 순환주기가 양액의 용존산소 농도, 엽채류의 생육, 그리고 식물영양소의 함량에 미치는 효과를 검토한 결과, 양액을 1일 10분 순환 처리구는 정식 13일 후 용존산소 농도가 급격하게 떨어지고 17일 후에는 2.8mg L-1, 20일 후에는 최저 1.5mg L-1까지 낮아졌다. 처리 20일 후 7가지 엽채류의 생체중은 1일 10분 처리구에서는 대조구인 10분 순환/110분 정지 처리구에 비해 0~24% 범위에서 낮아졌으며, 10분 순환/10분 정지 처리구에서는 -2~34% 증가하였다. 양액의 순환주기가 짧을수록 식물체 엽내 P의 함량이 증가하였으며, 식물체의 C/N율과 비타민 C 함량은 감소하였다. 이상의 결과, 담액수경 엽채류의 안정적인 생육과 식물영영소의 흡수를 위해서 2시간에 10분 정도의 양액 순환 처리가 효율적이었다.

본 연구는 돼지 체외수정란 생산효율을 향상시켜 돼지의 품종개량, 형질전환 돼지생산 등과 멸실위험에 처해 있는 유전자원의 보존을 위한 기술로 활용하기 위해 미성숙 난포란의 적정 체외성숙 시간을 알아보고, 배양액의 종류 및 체외 배양시의 산소 농도에 따른 체외수정란의 생산 효율을 확인한 결과는 다음과 같다. 1. 돼지 미성숙 난포란의 체외성숙 시간별 제2감수분열중기(M II)까지 성숙된 비율이 체외성숙 38, 40, 42시간째에 각각 61.1%, 42.9%

고 에너지 (1.5 MeV) 이온 주입된 Boron의 농도와 silicon 기판의 초기 산소 농도의 변화에 따라 silicon기판에 형성된 결정 결함 및 금속 불순물의 Gettering 효율에 대하여 DLTS(Deep Level Transient Spectroscopy), SIMS(Secondary ion Mass Spectroscopy), BMD(Bulk Micro-Defect) analysis 및 TEM (Transmission Electron Microscopy)을 이용하여 연구하였다. 이온 주입 전후의 DLTS 결과를 확산로 및 RTA를 이용한 열처리 전후의 DLTS 결과와 비교할 때 이온 주입 전 시편에서 볼 수 있는 공공에 의한 깊은 준위는 열처리 온도의 증가에 따라 금속 불순물과 관련된 깊은 준위로 천이함을 알 수 있다. 또한 고온 열처리의 경우, 초기 산소 농도가 높을수록 깊은 준위의 농도가 감소함을 볼 때 초기 산소 농도가 높을 수록 gettering 효율 측면에서 유리한 것으로 사료된다

일반적으로 LPCVD 방법에 의한 다결정 실리콘 박막은 SiH4가스를 열분해하여 증착한다. 본 실험에서는 다결정 실리콘 박막속에 포함된 산소농도를 낮추기 위하여 실리콘 웨이퍼를 반응로 안으로 장착할 때, 20slm의 N2가스를 반응로의 위에서부터 아래로 flow하였으며 박막의 산소농도를 측정하기 위하여 두께가 1000Å인 박막을 증착한 다음 SIMS로 분석한 결과 반응로의 hatch에 있는 짧은 injector를 통하여 20slm의 N2가스를 flow한 경우보다 박막의 산소농도가 ~30배 정도 낮아짐을 알 수 있었다. 긴 injector를 사용하여 증착된 박막의 두께 균일도, particle 및 Rs를 측정하여 박막증착의 재현성이 있음을 평가하였다.

The objectives of the present study were improvements in the efficiency of developmental rates to morula and blastocyst stages to produce a large number of genetically identical nuclear transplant embryos. The oocytes collected from slaughterhouse ovaries were matured for 24 h and then enucleated and cultured to allow cytoplasmic maturation and gain activation competence. And then the donor embryos were treated for 12 h with 10 g /ml nocodazole and 7.5 g /ml cytochalasin B to synchronize the cell cycle stage at 26 h after the onset of culture. The blastomeres were transferred into the perivitelline space of the enucleated nocytes and blastomeres and oocytes were fused by electrofusion. The cloned embryos were then cultured in various conditions to allow further development. The age of the recipient(30 vs 40 h) had no significant effect on the fusion rates(82.4 vs 82.1%) and the developmental rates to morula /blastocyst(9.8 vs 11.0%). Effect of Nocodazole treatment on the donor cell cyle synchronization to improve the developmental rates of bovine nuclear transplant embryos was significantly higher than control group(21.4 vs 10.1%, p<0.05). Significant differences were in the percentage of fusion rates(72.9,77.1vs 61.9%) in three types of fusion medium(PBS(+), mannitol and sucrose, p<0.01). The developmental rates of bovine nuclear transplant embryos appeared to be highest in mSOF medium under 5% 0 condition, but no significant differences were found when compared with TCM199-BOEC and mSOF under two different oxygen ratio(5 and 20%).

Rapid progress in urbanization has resulted in a change of the micro climate, especially in the urban area. In order to investigate the phenomenon of the heat island in the residential micro climate, a field survey was carried out by 4 sets of the residential type in Jeonju under typical winter synoptic condition. As analytic methode, it is used the comparison on the relation of the Land-to-Coverage Rate to Heat Island and Oxygen Concentration. And as a key question it is asked how stable characteristics of the micro climate will result from the survey of the Heat Island and the Oxygen Concentration, used as indicator. To ensure the trustworthy result of research, it is calculated the critical influence of the wind velocity and the Land-to-Covearage Rate. As a result of comparative analysis, it could be confirmed that the local temperatures in all sets of the residential type were higher than the average temperature in Jeonju. But the housing type A "exclusive use for housing zone" has relativly the most stable and best living condition. On the contrary the residential type B and D has the worst toward the oxygen concentration in the time zone 9-12 a.m., which didn't reach the minimum of the oxygen concentration 20.5%. It means that the higer the development and population density is, the worse is the situation of the Quality of Life in the residential types in accordance with the heat island and oxygon concentration.

참외 CA저장시 적정 농도 및 농도를 구명하기 위해 경북 성주산 참외 금싸라기 품종을 공시하여 농도를 5, 10, 15%로 하였고 농도는 3, 10%로 하여 15일, 30일, 45일 동안 각각 저장하여 실험한 결과는 다음과 같았다. 참외 저장후의 부패과율은 농도가 높을수록 낮았으며, 중량감소율은 저장 45일까지도 일반저온저장에서 5.01%, CA저장에서는 1.0%내외로 낮았다. 과육의 경도는 저장 30일까지는 일반저온저장, CA저장 모두 저장전과

This study was conducted to evaluate the effects of pressure and dissolved oxygen concentration on the activated sludge and to determine the optimum depth of deep shaft process. Some results from this study were summarized as follows. 1. It is considered that low sludge product in the activated sludge system maintaining high dissolved oxygen concentration is attributed to the increase of endogeneous respiration rate caused by the increase of aerobic zone in the sludge floc. 2. The increase of dissolved oxygen concentration does not affect to the increase of organic removal efficiency greatly and therefore the limiting factor is the substrate transfer into the inner part of floc. 3. The yield coefficient, Y is decreased in proportion to the increase of oxygen concentration. In this study, Y values arre ranged from 0.70 to 0.41 according to the variation of dissolved oxygen concentration from 18.0㎎/ℓ to 258 ㎎/ℓ. 4. The optimum depth of deep shaft process should be determined within the limits of non-toxicity to the microorganism and it is about 100m in this study.

The COD values and chloride ion concentrations of the Taewha river flowing through Ulsan area were determined along the main stream and the relationships between CODs and chloride ion concentrations were described. The results showed that the middle-upper stream and downstream of the Taewha river were polluted deeply with municipal sewage and self-purification occured in the middle-downstream of the river. When domestic sewage is a main source of pollutants, and is especially the only source of chloride in the stream water, the ratio of COD/[Cl^-] will be utilizable as a measure of self-purification of the stream.