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.

Weighing similarity against functionality to evaluate dung beetle species candidates for taxon substitution using an individual-based model

Jung-Wook Kho,Jung-Wook Kho,Joo-Young Kim,Do-Hun Gook,Hyunjoong Kim,Soowan Kim,Doo-Hyung Lee 한국응용곤충학회 2023 한국응용곤충학회 학술대회논문집 Vol.2023 No.04

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.

Path intersection matrices and applications to networks

Kho, D.Y.,Kook, W.,Lee, J.,Lee, J.,Lee, K.J. North Holland [etc.] 2017 Linear algebra and its applications Vol.524 No.-

<P>For a network G, we introduce a non-singular symmetric matrix, called a path intersection matrix, that will provide a new method for computing the ratio k(G)/k(G/ab) where k(G) is the tree-number of G and G lab is obtained from GUab by contracting the new edge ab between two distinct nodes a and b. The quantities k(G)/k(G/ab) appear as invariants for various networks such as effective conductance for an electrical network and an ingredient for information centrality for a social network. We will review several examples of networks where path intersection matrices can be applied. (C) 2017 Elsevier Inc. All rights reserved.</P>

A report of three unrecorded Ovulid species (Gastropoda, Heterodonta) from Korea

Kho, Dong-Bum,Lee, Jun-Sang,Min, Duk-Ki The Malacological Society of Korea 2015 The Korean Journal of Malacology Vol.31 No.1

Three Ovulid species collected from Jeju Island were identified as Habuprionovolva aenigma (Azuma & Cate, 1971), Habuprionovolva basilia (Cate, 1978) and Diminovula kosugei (Cate, 1973). This is the first record from the Korean waters, providing a description of the species with illustration for the shell morphology.

Genetic and environmental influences on sodium intake determined by using half-day urine samples: the Healthy Twin Study

Kho, Minjung,Lee, Jung Eun,Song, Yun-Mi,Lee, Kayoung,Kim, Kyunga,Yang, Sarah,Joung, Hyojee,Sung, Joohon American Society for Clinical Nutrition 2013 The American journal of clinical nutrition Vol.98 No.6

<P><B>Background:</B> Salt is essential in our diet, but excess intake is a well-established risk factor for hypertension. The presence and importance of genetic contributions to salt intake, however, are not well understood.</P><P><B>Objective:</B> The aim of this study was to examine whether a genetic predisposition and an environmental influence exist for sodium intake and salt habit.</P><P><B>Design:</B> In a twin-family cohort, half-day urine samples from 1204 individuals (133 pairs of monozygotic twins, 29 pairs of dizygotic twins, and 880 singletons) were collected to assess 24-h sodium intakes. Daily total sodium intake, sodium density per calorie (Na-D), and salt habit questions were analyzed with adjustment for other epidemiologic characteristics. We calculated heritability (h2) and intraclass correlations to examine the genetic and shared environmental contributions to total sodium intake traits.</P><P><B>Results:</B> The average sodium intake was 208.4 ± 107.0 mmol/d. Men had a higher absolute sodium intake (242.6 ± 117.4 mmol/d), but Na-D did not differ by sex. Moderate genetic influences existed (h2 = 0.31–0.34) for sodium intake and Na-D. We also found that sharing current residence rather than being a family member explained 22% of the variance in Na-D.</P><P><B>Conclusion:</B> Our findings suggest that both genetic predisposition and shared environment contribute to sodium intakes and salt habits alike.</P>

Agora and Its Possibilities in James Joyce’s “Wandering Rocks”

Kho, Younghee 미래영어영문학회 2021 영어영문학 Vol.26 No.1

Reviving and representing the concept of agora, a central space for the politics, economy, and religion of ancient Greek city-states, this paper claims that Joyce in Dubliners and Ulysses evaluates the limitations and possibilities of Ireland as an emerging nation through the citizens’ interactions in agora. Focusing on this public space’s role for communication, the paper pays attention to the kinds and characters of communication especially in “Eveline” and “Wandering Rocks.” In the former story, Eveline is occupied in her uncommunicable concern of whether or not she has to leave Ireland, yet her agoraphobia ultimately ends her communication with others, especially with Frank who she regards as a possible savior from her stifling situation. The citizens in “Wandering Rocks” do not show such physical symptoms of agoraphobia as Eveline; however, their consciousness and communication still expose what obstructs themselves from intellectual development. The pretentious and uncharitable attitude of Dubliners, perhaps except for foreign Bloom and female Molly, marks their communication everywhere and develops a false community in this episode. Molly and Bloom, in contrast, open up possibilities for building an ideal community through the act of charity, which is particularly emphasized in this episode.

Life Under Fetters: Trevor’s “The Potato Dealer” and Kavanagh’s “The Great Hunger”

Kho, Younghee 미래영어영문학회 2020 미래영어영문학회 학술대회 자료집 Vol.2020 No.12

Effects of Cryoprotectants and Freezing Rates on Cryopreservation of Catfish, Silurus asotus Sperm

Kho, Kang Hee,Kang, Kyoung Ho The Korean Society of Fisheries and Aquatic Scienc 2004 韓國養殖學會誌 Vol.17 No.1

Milt of the catfish was stripped into immobilizing solution containing 175 mM NaCl and 30 mM Tris at pH 7.8 and was successfully cryopreserved after a stepwise freezing procedure. After stepwise thawing, motility of spermatozoa was slightly lower than that of fresh sperm. Batches of 40-80 eggs were fertilized with cryopreserved spermatozoa, after thawing and activation in solution containing 50 mM NaCl, 20 mM Tris and HCl at pH 7.8; this resulted in 62.2% fertilization success, compared to 70.6 % with fresh sperm.