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동형 모더나이트 상에서 일산화탄소 산화반응에 대한 속도론
정명수,이창용,최고열,하백현 漢陽大學校 環境科學硏究所 1989 環境科學論文集 Vol.10 No.-
모더나이트에 동을 이온교환 및 담지시킨 후 환원·산화 처리를 하여 동의 상태를 변화시킨 촉매에 대해 일산화탄소 산화반응의 속도론적인 고찰을 행하였다. 이온교환 촉매나 담지촉매 모두 동의 상태와는 관계없이 일산화탄소에 관한 반응차수는 1차이고 산소에 관한 반응차수는 0차였다. 이온교환 촉매의 경우는 수소로 환원시켜 동이 금속상태로 존재할때와 이를 재산화시켜 산화동 상태로 존재할때는 활성화에너지가 각각 16.4 및 20.3으로 비교적 큰 값을 나타냈으나 동의 담지촉매의 경우는 동이 금속일 때나 산화물 상태 모두 12∼13kcal/mole로 비슷한 값을 나타냈으며 이온교환 촉매보다 상당히 감소함을 알 수 있었다. 이와 같은 결과는 이온교환 촉매의 경우는 동이 제올라이트내부에 대부분 존재하는 반면, 담지촉매의 경우는 제올라이트 결정 표면에 존재하기 때문에 활성을 증가시키는 것으로 생각된다. Kinetics of oxidation of carbon monoxide over copper mordenite was carried out at the temperature range between 373K-443K in the micro-catalytic reactor. The experimental results indicated that the reaction order, with respect to carbon monoxide and oxygen was first and zero order respectively, regardless of the valence states such as copper metal, copper ion and copper oxide on the mordenite. The activation energy for metal-copper mordenite which is obtained by the ion-exchange revealed 20kcal/mol. But if this was reoxidized under the oxygen it decreased to 16.6kcal/mol. The activation energy of metal-copper mordenite which was obtained by impregnation and its reoxidized one under the oxygen were 12.2kcal/mol and 13.3kcal/mol respectively.
고분자 전해질형 연료전지에서 Hot Pressing 조건의 영향
이태희,이승재,조원일,노용우,고영태,최경환 한국화학공학회 1996 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.34 No.1
고분자 전해질형 연료전지에서 고분자막/전극 어셈블리를 hot pressing 조건을 달리하여 제조하고 그 성능을 반응면적 5㎠인 단위전지에서 측정하였다. 전지의 성능은 고분자막과 전극간의 접합이 가능한 온도 범위에서 hot pressing온도가 낮을수록, hat Pressing 압력이 높을수록 향상되었다. 즉, 고분자 전해질형 연료전지의 성능은 고분자 전해질 내의 수분 함량 증가, 고분자막/전극간 접촉저항 감소 및 얇은 고분자막을 사용한 전해질의 이온저항 감소 등으로 향상시킬 수 있었다. For a proton exchange membrane fuel cell, membrane and electrode assemblies were fabricated by different hot pressing conditions and those performances were observed in a unit cell having 5 ㎠ active electrode area. The cell performance increased with lower hot pressing temperature in the range of temperature having intimate contact between membrane and electrodes and with higher hot pressing pressure. Namely, the performance of proton exchange membrane fuel cell could be raised with higher water content in the membrane, with lower contact resistance between membrane and electrodes and with lower ion resistance of the electrolyte using thinner membrane.
Kho Sam il,Kim Min Su,Sohn Sun Young,Jung Dong Geun,Boo Jin Hyo,Jeong Seong Hoon,Park SangHee Ko The Korean Vacuum Society 2005 Applied Science and Convergence Technology Vol.14 No.4
For the longevity of OLEDs, passivation of OLEDs is an important process step since organic materials used in OLEDs are very vulnerable to moisture. In this work, the passivation effect of the plasma polymerized para-xylene (PP$\rho$X) layers was studied. The PPpX layers deposited by PECVD were formed on top of the cathode with various plasma powers of 50 - 90 W. Passivation effect of PP$\rho$X was significantly dependent upon the deposition plasma power of the PP$\rho$X film. The lifetime of OLEDs with the 70 W deposited PP$\rho$X passivation layer was about 5 times longer than that of the control device.
Acute Effects of Tobacco and Non-tobacco Cigarette Smoking on the Blood Pressure and Heart Rate
Kho Young-Lim,Yi Sang-Gu,Lee Eun-Hee,Chung Moon-Ho Korean Society of Environmental Health 2006 한국환경보건학회지 Vol.32 No.3
Smoking of tobacco cigarettes is associated with a rise in blood pressure together with increase in heart rate. This study was aimed to examine the acute effect of tobacco and non-tobacco cigarette smoking on the blood pressure and heart rate by randomized crossover study. In the results, systolic/diastolic blood pressure and heart rate changes after smoking were significantly different between male and female group. Blood pressure and heart rate were elevated after smoking, but statistical significance for the difference was identified only in the female group. Because Non-tobacco smoke made from leaves of E. ulmoides has no nicotine, its effect on blood pressure and heart rate was negligible. Remarkable difference of heart rate changes in women was observed between tobacco cigarette smoking group and non-tobacco cigarette smoking group.
Cryopreservation of Pointhead Flounder (Cleisthenes pinetorum herzensteini) Sperm
Kho, Kang Hee,Kang, Kyoung Ho 한국어류학회 2003 韓國魚類學會誌 Vol.15 No.4
용가지마 정자(Cleisthenes pinetorum herzensteini)를 액체질소를 이용하여 동결 보존하였고, 동결에 따른 정자의 운동성, 생존율 그리고 미세구조의 변화를 조사하였다. 정자의 운동성은 30% 인공해수(ASW)에서 운동성이 억제되었고, 100% 인공해수의 첨가에 의해 운동성이 개시되었다. 동해방지제로는 DMSO와 glycreol를 30% ASW에 최종농도가 5~20% 되도록 첨가하여 사용하였다. 그 결과 10% glycerol을 동해방지제로 하였을 때 정자의 운동성 및 생존율이 가장 높게 나타났으며 동결속도는 분당 20℃씨 - 80℃까지 내렸을 때 가장 보존효과가 높게 나타났다. 동결보존한 정자의 원형질막이 핵에서 분리되는 현상이 관찰되었다. In the present study, attempts were made to cryopreserve sperm of the pointhead flounder (Cleisthenespinetorum herzensteini) in liquid nitrogen to evaluate effects of various cryoprotectants and freezing rates on the motility and survival rate, and to identify the ultrastructural changes of sperm after cryopreservation. Sperm motility was significantly inhibited in 30% artificial seawater (ASW), but was restored entirely after 100% ASW was added again. Two cryoprotectants, dimethyl sulfoxide (DMSO) and glycerol, were added to 30% ASW to formulate the extenders at concentrations between 5% and 20% by volume for freezing. The highest post-thawed sperm motility and survival rate were obtained with 10% glycerol. Afterward, the effect of different freezing rates was examined using 10% glycerol as a cryoprotectant, and the rate of 20℃/min to -80℃ showed the best result. Ultrastructural changes of the detachment of plasma membranes were observed after cryopreservation.
Cancelable fingerprint template design with randomized non-negative least squares
Kho, Jun Beom,Kim, Jaihie,Kim, Ig-Jae,Teoh, Andrew B.J. Elsevier 2019 Pattern recognition Vol.91 No.-
<P><B>Abstract</B></P> <P>Although biometrics is considered more competent than password-based or token-based approach in identity management, biometric templates are vulnerable to adversary attacks that may lead to irreversible identity loss. One of the promising remedies for biometric template protection is cancelable biometrics. In this paper, a novel binary cancelable fingerprint template design based on Partial Local Structure (PLS) descriptor and Permutated Randomized Non-Negative Least Square (PR-NNLS) is proposed. The PLS descriptor is an alignment-free minutia descriptor, which is conceived to be coupled with the PR-NNLS to derive a binary protected fingerprint template that satisfies non-invertibility, unlinkability, cancelability and performance criteria. The PR-NNLS formulation is unique in such a way that the noninvertible transformation is applied to the PLS descriptor dictionary instead of applying it to the minutiae descriptor, which often invites performance deterioration. The evaluations have been carried out with five subsets from FVC 2002 and 2004 databases where the proposed method is attested to fulfill the aforementioned four template protection criteria. We also analyze four privacy and security attacks targeted to cancelable biometrics.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel alignment-free minutiae descriptor that based on Partial Local Structure (PLS) is proposed, which is beneficial to generate discriminative and compact binary cancelable fingerprint template. </LI> <LI> The non-invertible transformation of the PLS descriptor is formulated as a problem of solving randomized Non-Negative Least Square (R-NNLS) optimization problem, which is unique in a way to get rid of the performance deterioration issue when applying the non-invertible transformation directly to the minutiae descriptor for the fingerprint template protection. </LI> <LI> The revocability and the unlinkability traits of the proposed method are enabled by introducing a permutation mechanism to the R-NNLS. </LI> <LI> The proposed method is rigorously evaluated with five benchmark datasets, and four security and privacy analyses are also carried out. </LI> </UL> </P>