• 한국식품영양과학회지
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• 제20권3호
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• pp.214-219
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• 1991

상대습도 65%, 온도 $35^{\circ}C$의 저장 조건하에서 지방질의 가수분해를 촉진 시킨 미강과 상대습도 70-90% 온도 $25-30^{\circ}C$의 공기중에 방치하여 가수분해와 산화를 동시에 촉진시킨 미강을 시료로 지방질의 산화에 따라 생성된 산화 생성물이 단백질의 변패에 미치는 영향을 유리아미노산 함량의 경시적인 변화로써 살펴 보았다. 산소농도를 제한한 system에서는 자장초기에 유리아미노산의 함량이 증가하다가 지방질의 산화가 진행되면서 감소하기 시작하였고, 이러한 감소현상은 공기중에 방치한 실험군에서는 저장 초기부터 일어나기 시작하여 산화가 급격하게 진행된 저장 말기에는 그 감소 현상이 현저하였다. 이들 아미노산의 감소와 지방질의 산패정도를 통계처리한 결과, 유리아미노산 중 serine, glutamic acid, proline, methionine, lysine, histidine, 그리고 arginine 등의 함량 감소는 지방질의 산패에 의한 현저한 영향을 받았다(p<0.05).

• 한국전기전자재료학회논문지
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• 제18권2호
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• pp.169-173
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• 2005

Ni oxide thin films were formed through annealing treatment in the atmosphere after Ni thin films deposited by a r.f. magnetron sputtering method and then electric and material properties were analyzed for application to thermal sensors. Resistivity of Ni thin films decreased after annealing treatment at 30$0^{\circ}C$ and 40$0^{\circ}C$ for five hours due to crystallization of Ni thin films but the value increased over 45$0^{\circ}C$ because of Ni thin film's oxidation. Resistivity values of Ni thin films were in the range of 10.5 $\mu$Ωcm/$^{\circ}C$ to 2.84${\times}$10$^4$$\mu$Ωcm/$^{\circ}C$ according to the degree of Ni oxidation. Also temperature coefficient of resistance(TCR) values of Ni oxide thin films depended on the degree of Ni oxidation such as 2,188 ppm/$^{\circ}C$ to 5,630 ppm/$^{\circ}C$ in the temperature range of 0 $^{\circ}C$∼150 $^{\circ}C$. The results demonstrate that Ni oxide thin films of annealing treatment at 40$0^{\circ}C$ for 5hours could be more advantageous than pure Ni thin films and Pt thin films from a point of output properties and TCR, applied to thermal sensors.

• 한국식품영양과학회지
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• 제39권7호
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• pp.1011-1017
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• 2010

본 연구에서는 감자튀김 횟수에 따른 각종 식용유지의 화학적 특성 변화를 측정하였다. 식용유지로서는 sunflower oil(SO), canola oil(CO) 및 frying oil(FO)을 사용하였으며, 튀긴 감자에서 추출한 기름의 지방산 조성 변화와 산화 안정성에 대하여 실험하였다. 튀긴 감자에서 추출한 기름의 산화정도는 산가와 과산화물가를 측정하였다. CO 및 FO를 사용하여 튀긴 감자에서 추출한 기름에 대한 산가는 튀김 횟수가 30회의 경우 초기보다 각각 0.20, 0.17 증가한 결과를 나타내었다. SO의 산가는 CO와 FO에 비하여 그 값이 낮게 나타났다. 과산화물가 측정 결과는 일률적으로 증가하지는 않았다. 지방산 조성 변화에 대하여 측정한 결과 SO 및 FO를 사용하여 감자를 튀긴 경우 튀김 반복횟수가 증가할수록 oleic acid 함량은 감소하고 linoleic acid 함량은 증가하였다. 벤조피렌 생성 유무 측정 결과는 SO, CO 및 FO에서 튀김 초기와 반복횟수에 따라서 큰 변화는 나타나지 않았다. 이러한 결과 튀김에 사용한 식용유지 종류 및 튀김 반복 횟수에 따라서 지방산 조성에 변화가 나타나며 그로 인하여 유지의 산화 안정성에 영향을 미침을 알 수 있었다.

• Advances in nano research
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• 제13권6호
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• pp.513-525
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• 2022

In this study, it was aimed to evaluate direct oxidation of aqueous solution containing cefalexin antibiotic with new generation Sn/Sb/Ni: 500/8/1 anode. The fact that there is no such a study on treatment of cefalexin with these new anode made this study unique. According to the operating parameters evaluation COD graphs showed clearer results compared to TOC and CLX and thus, it was it was chosen as major parameter. Furthermore, pseudo-first degree kd values were calculated from CLX results to show more accurate and specific results. Experimental results showed that after 60 min of electrochemical oxidation, complete removal of COD and TOC was accomplished with 750 mg L^-1 KCl, at pH 7, 50 mA cm^-2 current density and 1 cm anode-cathode distance. Also, the stability of the Sn/Sb/Ni anode was evaluated by taking SEM and AFM images and XRD analysis before and after of electrochemical oxidation processes. According to the results, it was not occurred too much change on the anode surface even after 300 h of electrolysis. Thus, it was thought that the anode material was not corroded to a large extent. Furthermore, the removal efficiencies were very high for almost all the time and conditions. According to the results of the study, electrochemical oxidation with new generation Sn/Sb/Ni anodes for the removal of cefalexin antibiotic was found very successful and applicable due to require less reaction time complete mineralization and doesn't require pH adjustment step compared to other studies in literature. In future studies, different antibiotic types should be studied with this anode and maybe with real wastewaters to test applicability of the process in treatment of pharmaceutical wastewaters containing antibiotics, in a better way.

• Corrosion Science and Technology
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• 제20권3호
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• pp.158-168
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• 2021

Austenitic 316 stainless steel was irradiated with protons accelerated by an energy of 2 MeV at 360 ℃, the various defects induced by this proton irradiation were characterized with microscopic equipment. In our observations irradiation defects such as dislocations and micro-voids were clearly revealed. The typical irradiation defects observed differed according to depth, indicating the evolution of irradiation defects follows the characteristics of radiation damage profiles that depend on depth. Surface oxidation tests were conducted under the simulated primary water conditions of a pressurized water reactor (PWR) to understand the role irradiation defects play in surface oxidation behavior and also to investigate the resultant irradiation assisted stress corrosion cracking (IASCC) susceptibility that occurs after exposure to PWR primary water. We found that Cr and Fe became depleted while Ni was enriched at the grain boundary beneath the surface oxidation layer both in the non-irradiated and proton-irradiated specimens. However, the degree of Cr/Fe depletion and Ni enrichment was much higher in the proton-irradiated sample than in the non-irradiated one owing to radiation-induced segregation and the irradiation defects. The microstructural and microchemical changes induced by proton irradiation all appear to significantly increase the susceptibility of austenitic 316 stainless steel to IASCC.

• 한국산업융합학회 논문집
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• 제15권3호
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• pp.71-77
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• 2012

This study gives the optimal reaction conditions, reaction mechanisms, reaction rates leaded from the oxidation of phenol by electron beam accelerator and ozone used for recent water treatment. It gives the new possibility of water treatment process to effectively manage industrial sewage containing toxic organic compounds and biological refractory materials. The high decomposition of phenol was observed at the low dose rate, but at this low dose rate, the reaction time was lengthened. So we must find out the optimal dose rate to promote high oxidation of reactants. The reason why the TOC value of aqueous solution wasn't decreased at the low dose was that there were a lot of low molecular organic acids as an intermediates such as formic acid or glyoxalic acid. In order to use both electron beam accelerator and biological treatment for high concentration refractory organic compounds, biological treatment is needed when low molecular organic compounds exist abundantly in sewage. In this experiment, the condition of making a lot of organic acids is from 5 kGy into 20 kGy dose. Decomposition rate of phenol by electron beam accelerator was first order reaction up to 300ppm phenol solution on the basic of TOC value and also showed first order reaction by using both air and ozone as an oxidants.

• Advances in environmental research
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• 제5권4호
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• pp.251-262
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• 2016

The biodegradability and decomposition efficiencies increase with the pre-treatment of sludge in a digestion process. In this study, the feasibility of ultrasound coupled with potassium permanganate oxidation as a disintegration method and digestibility of aerobic reactor fed with disintegrated sludge with ultrasound coupled potassium permanganate were investigated. The first stage of the study focused on determining the optimum condition for ultrasonic pre-treatment for achieving better destruction efficiency of sludge. The second part of the study, the aerobic digestibility of sludge disintegrated with ultrasound and potassium permanganate oxidation alone and combined were examined comparatively. The results showed that when 20 min of ultrasonic pre-treatment applied, the specific energy output was 49384 kJ/kgTS with disintegration degree of 58.84%. During the operation of aerobic digester, VS/TS ratios of digesters fed with disintegrated sludge decreased indicating that disintegration methods could obviously enhance aerobic digestion performance. The highest reduction in volatile solids was 75% in the digester fed with ultrasound+potassium permanganate disintegrated sludge at the end of the operation compared to digester fed with raw sludge. Total Nitrogen (TN) and Total Phosphorus (TP) levels in sludge supernatant increased with this combined method significantly. Besides, it promoted the production of ${\bullet}OH$, thus enhancing the release of Carbon (C), Nitrogen (N) and Phosphorus (P) from the sludge. Disintegration with all methods used in this study could not improve Capillary Suction Time (CST) reduction in disintegrated digesters during the operation. The results demonstrated that the combined ultrasound treatment and potassium permanganate oxidation method improves the biodegradability compared to control reactor or their single application.

• 동아시아식생활학회지
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• 제7권3호
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• pp.315-324
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• 1997

1.5, 3.0, 4.5, 6.0% active Cl/g starch를 포함하는 sodium hypochlorite 용액으로 pH 7.0에서 감자전분을 산화시켜 이화학적인 성질을 측정하였다. 산화 전분의 카르복실기 함량은 사용한 활성 염소농도에 비례하였고, 물결합력과 알칼리수, 용해도는 산화 정도가 높을수록 증가하였다. 청가와 요오드흡착특성에서는 산화에 의해 아밀로오스 구조가 변화되었음을 알 수 있었고, 광투과도와 DSC에 의한 호화양상에서는 산화 정도가 클수록 낮은 온도에서 호화되는 것으로 나타났다. X선 회절도와 주사전자 현미경으로 살펴 본 전분 입자의 형태로부터 산화는 주로 입자 표면의 무정형 부분에서 일어난 것으로 추정되었다.

• 한국산학기술학회논문지
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• 제6권3호
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• pp.270-272
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• 2005

코발트 실리사이드는 낮은 전기 저항성 때문에 고효율 소자를 제조하는데 적합한 물질이다. 이는 전자소재가 소형화되면서 접촉저항과 혼합을 줄이기 위해 더욱 필요하게 되었다. 본 연구에서는 티타늄의 표면산화에 미치는 영향과, RTO 조건에서 온도에 따른 코발트 실리사이드 박막의 산화정도를 측정했다. 기질로서 p-형 실리콘웨이퍼를 사용하였고, 고속 열 가공을 통하여 박막을 가공하였다. 티타늄 층을 입혔을 때 산화충의 두께는 $500{\AA}$정도 성장하였다. 고속 열산화의 온도변화에 따라 산화막은 $550^{\circ}C\~700^{\circ}C$까지는 성장을 보였으나 $700^{\circ}C$이상에는 산화막 성장이 포화상태를 보였다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.33-36
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• 2003

AC and DC conductivity of the MWNT(Multi walled nanotubes)/polyurethane composites were investigated with respect to the various oxidative conditions, where these means acid concentration, treatment temperature, and treatment time. We suppose that the conditions of oxidation of the MWNTS have a certain influence on the degree of functionalization, damages, and dispersion of the MWNT themselves. Futhermore, the electrical properties of the resulting composites strongly depend on the oxidative conditions of MWNTS. The conductivity of the composites produced by using the optimal condition was measured as a function of frequency with volume content of MWNTS. These experimental results were analyzed using percolation theory Electromagnetic interference shielding effectiveness (SE) of the mixtures of polyurethane (PU), optimized MWNTs, and silver (Ag) is measured in the frequency range from 10 MHz to 6 ㎓ by using ASTM D4935-89. The measured SEs of the mixtures could be controlled from about 55 dB to 85 dB with the compositions of Ag/MWNT and compounding methods(C1, C2).