Controlled infiltration profile of SiC coating layer on graphite by Si vapor deposition reaction

Kuk-Jin Hwang,Si-Young Bae,Kyoung-Ho Kim,Yoon-Cheol Lee,Jung-Tae Hwang,Heesoo Lee,Seong Min Jeong,Myung-Hyun Lee 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.2

SiC-coated graphite was successfully fabricated at different temperatures (1300-1600 oC) through a silicon vapor depositionreaction (Si-VDR) process. Si powder was used for the Si source of the SiC coating layers. When Si powder was evaporatedat high temperature near the melting point of bulk Si, Si gases are moved and changed into Si liquid at the surface of thegraphite. The high-temperature process facilitated the formation of SiC coating layers on the graphite. The microstructural,mechanical, and thermal oxidation properties of the coated graphite were investigated.

Effects of Phenytoin and Diazepam on the Seizure Activity in the Cortical Dysplasia Animal Models

Kim, Si-Hyung,Choi, In-Sun,Cho, Jin-Hwa,Park, Eun-Ju,Jang, Il-Sung,Choi, Byung-Ju,Kim, Hyun-Jung,Kim, Young-Jin,Nam, Soon-Hyeun The Korean Academy of Oral Biology 2006 International Journal of Oral Biology Vol.31 No.2

Dysplasia-associated seizure disorders are markedly resistant to pharmacological intervention. Relatively little research has been conducted studying the effects of antiepileptic drugs(AEDs) on seizure activity in a rat model of dysplasia. We have used rats exposed to methylazoxymethanol acetate(MAM) in utero, an animal model featuring nodular heterotopia, to investigate the effects of AEDs in the dysplastic brain. Pilocarpine was used to induce acute seizure in MAM-exposed and age-matched vehicle-injucted control animals. Field potential recordings were used to monitor amplitude and numbers population spikes, and paired pulse inhibition in response to stimulation of commissural pathway. Two commonly used AEDs were tested: diazepam 5, 2.5mg/kg;phenytoin 40, 60mg/kg. Diazepam(DZP) and phenytoin(PHT) reduced the amplitude of population spike in control and MAM-exposed rats. However, the amplitude of population spike was nearly eliminated in control rats as compared to the MAM-exposed rats. Pharmaco-resistance was tested by measuring seizure latencies in awake rats after pilocarpine administration(320mg/kg, i.p.) with and without pretreatment with AEDs. Pre-treatment with PHT 60 mg prolonged seizure latency in control rats, but not in MAM-exposed animals. The main findings of this study are that acute seizures initiated in MAM-exposed rats are relatively resistant to standard AEDs assessed in vivo. These data suggest that animal model with cortical dysplasia can be used to screen the effects of potential AEDs.

Inclusions Nucleating Intragranular Polygonal Ferrite and Acicular Ferrite in Low Alloyed Carbon Manganese Steel Welds

박경태,Si Woo Hwang,Jung Hoon Ji,이창희 대한금속·재료학회 2011 METALS AND MATERIALS International Vol.17 No.2

The inclusion-assisted formation of two types of intragranular ferrite in low alloyed C-Mn steel welds, intragranular polygonal ferrite (IPF) and acicular ferrite (IAF), was investigated in relation to the inclusion characteristics (mainly size and chemistry) and the welding heat input. For this analysis, inclusions engulfed by one ferrite grain and those shared by two ferrite grains were considered as the IPF nucleants, and the rest of them (in contact with more than three ferrite grains) were considered as the IAF nucleants. All inclusions were multi-component oxides having Ti oxides as the nucleoid. The inclusion size exhibited a log-normal distribution and the average size increased as the heat input increased. Inclusions larger than ~0.4 μm were found to be effective on IAF nucleation, and the effectiveness increased as the inclusion size increased. Accordingly,the overall IAF nucleant fraction increased as the heat input increased due to the corresponding inclusion size increase. However, the probability of the IAF nucleant in the same inclusion size range was insensitive to the heat input. There was no difference in the elemental distribution between the IAF and IPF nucleants except for Si. The Si distribution was uniform in the IPF nucleants while its content was relatively high at the inclusion periphery in the case of the IAF nucleants regardless of the heat input and the inclusion size.

수원 일월저수지에서 Microcystis aeruginosa (K$\ddot{u}$tzing) K$\ddot{u}$tzing 수화현상 시 환경요인들의 변화

김지은,박정원,조기안,김시균,Kim, Ji-Eun,Park, Jung-Won,Jo, Ki-An,Kim, Si-Kyoon 한국하천호수학회 2013 생태와 환경 Vol.46 No.2

본 연구는 수원 일월저수지에서 수화현상 시 환경요인들의 변화와 한국형 부영양화 지수를 이용하여 영양단계를 평가하였다. 수화현상 종은 남조류의 Microcystis aeruginosa Kutz.였으며 조사기간 내내 우점하였다. 수온은 평균 $25.7{\sim}28.4^{\circ}C$, pH는 8.4~11.17, CODcr는 4.25~$72.0mg\;L^{-1}$, 전기전도도는 333.1~$749.0{\mu}S\;cm^{-1}$, Chl-a는 22.0~$185.0mg\;L^{-1}$였다. 정체 수역인 정점 2에서 CODcr는 다른 정점에 비해 2.9배 정도로 높아 내부기원 유기물의 기여도가 높은 것으로 판단된다. 영양염인 TN은 평균 28.86~$56.75mg\;L^{-1}$, TP는 0.2~$1.24mg\;L^{-1}$로 매우 높았고, Fe는 0.11~$1.05mg\;L^{-1}$이었고, Si는 3.13~$7.46mg\;L^{-1}$이었다. TN과 TP는 일월저수지 내에 지속적으로 누적된 것으로 파악되었고, Fe도 높은 농도가 유지되었다. 한국형 부영양화지수는 37.19~147.22였다. 영양단계는 중영양에서 과영양 단계로 평가되었고, 같은 저수지 내에서도 시기 및 지점에 따라 영양단계가 다름을 나타내므로 많은 자료가 추적된다면 한국형 영양단계 분석은 저수지의 영양단계 분석 시 매우 유용하게 활용될 것으로 판단된다. Variances in environmental factors were followed in Ilwol reservoir, Suwon, during bloom of Microcystis aeruginosa (K$\ddot{u}$tzing) K$\ddot{u}$tzing, Cyanophtya from August to October, 2011. M. aeruginosa dominated the water column throughout the investigation period. The water temperature varied from $25.7^{\circ}C$ to $28.4^{\circ}C$, pH 8.40 to 11.17, CODcr 4.25 to $72.00mg\;L^{-1}$, electrical conductivity 333.1 to $749.0{\mu}g\;cm^{-1}$, and Chl-a 22 to $185mg\;L^{-1}$. In particular, the high levels of CODcr is likely indicate high contribution of autochthonous organic matters in the reservoir. TN varied from 28.86 to $56.75mg\;L^{-1}$, TP 0.20 to $1.24mg\;L^{-1}$, Fe 0.11 to $1.05mg\;L^{-1}$, and Si 3.13 to $7.46mg\;L^{-1}$. These increases imply constant accumulation in Ilwol reservior, and reinforce the idea of autochthonous organic matters input in the reservoir. The Korea Trophic Status Index ($TSI_KO$) varied from 37.19 to 147.22. Trophic levels varied from mesotrophic to hypertrophic level, and differed spatio-temporally. Therefore, it is concluded that $TSI_KO$ is useful for analyzing trophic status of reservoirs.

슬관절통 환자에서 초저온 냉기를 이용한 한냉치료후시각적상사척도값의 변화

이정권,김미정,박시복,김영호 大韓再活醫學會 1999 Annals of Rehabilitation Medicine Vol.23 No.1

응집공정에 적합한 In-Line 정적혼화기를 이용한 혼화공정의 개선

정철우,강민수,최시환,정수일,손인식,강임석 대한상하수도학회 2003 상하수도학회지 Vol.17 No.3

The rapid mixing process for coagulation is a critical component in a water treatment plant. However, at the present time a detailed understanding of the rapid mixing by in-line mixer or generally accepted criteria for the design of in-line static mixer are not available. The aim of this work is therefore to improve the understanding of how the in-line static mixer works and how to better utilize it in coagulation process in water treatment. To investigate the performance of static mixer, coagulation experiments were conducted to compare the static mixer to the traditional backmixer under several coagulation conditions. Experiments were also performed to compare the coagulation efficiency of different mixing type of static mixer which were made using different flow rates and the number of elements equipped in a pipe. The static mixer performed better than the backmixer for all coagulation and mixing conditions tested. Especially, the static mixer was very effective in the surface charge neutralization, as showing higher reduction of negative charge with increasing mixing intensity. However, little difference was observed in the performance of the static mixer equipped with 2, 3, and 5 elements. Also, in a series of bench-scale studies of rapid mixing, the in-line static mixer performed better than the traditional backmixer for both adsorption and charge neutralization (A/N) mechanism and sweep coagulation mechanisms. Especially, the static mixer was more efficient at producing A/N mechanism conditions as a result of its fast and uniform dispersion of the coagulant.

朝鮮王朝時代의 科學制度硏究

丁時采 건국대학교 1979 論文集 Vol.10 No.1

The purpose of the thesis lies in grasping the basic characteristics and contents of the bureaucratic system of Yi Dynasty by studying and analizing the context of public examinations of the dynasty. The thesis is composed of types, applicants' qualifications, procedures of the public examination, and the treatment of successful applicants together with preface and conclusion. The public examination was classified into three types such as civil service examination, military service examination, and technical service examinaiton. The public examinations were undertaken in two ways. The ordinary examination named "Siknyonsi" was periodically given every three years, while the special examination was provided on the occasion of national happy events or in temporary need of additional officials. The eligibility to undergo the public examination was not given to everybody but to some specific clashes. Particularly those who belonged to upper classes named "Yangban" were only qualified to apply for the examination :or civil service. The number of the recruited was 33 in case of the ordinary examination, but not fixed in case of the special examination. Since the public examination was a kind of qualifying examination, the successful applicants for the civil or military service examinations were qualified to get the status of the junior grade of 5th to 9th rank and those for the technical service examination to gain the status of the junior grade of 8th to 9th rank. The public examination system made great contribution to the establishment of centralized bureaucratic government arid the selection of able officials. However, even the political turmoil was caused by so many officials recruited through the public examination, and the subjects that stressed poems and compositions too much led to the fostering formalism of learning.

항울제 및 항정신병 약물로 유발된 섬망상태 1례

정향균,김영철,이시형 大韓神經精神醫學會 1988 신경정신의학 Vol.27 No.2

The authors reported a case of tricyclic and antipsychotic agent induced delirium. The patient was a 64 years old man who had been treated by drugs with anticholinergic properties (amitriptyline-thioridazine combination) and showed the characteristic symptoms of delirium such as confused mentality, disorientation, auditory and visual hallucination, the change of diurnal cycle, attention disturbance and hyperactivity. Discontinued the administration of amitriptyline and thioridazine and substituted haloperidol and lorazepam, delirious symptoms were improved within 5 day.

곰팡이 오염된 사료를 섭취한 개에서 신부전과 calcium oxalate-like crystal

육현정,손화영,류시윤,조성환 충남대학교 수의과대학 동물의과학연구소 2004 動物醫科學硏究誌 Vol.12 No.-

In March and July 2004, 2-year-old female Yorkshire Terrier and 7-year-old female Shih-Tzu were referred to the College of Veterinary Medicine, Chungnam National University. Clinically, two dogs showed anorexia, vomiting and emaciation. The signs had occurred after the dogs were fed diets infected with oxalate-producing fungi. At necropsy, Shih Tzu had severe renal damage with the green-yellowish colored uroliths in the renal pelvis and the both kidneys were extremely reduced in sizes. Microscopically, Yorkshire Terrier had acute nephritis contained necrotized and degenerated tubular epithelial cells in cortex. Numerous calcium oxalate-like crystals were infiltrated into most tubules, especially the proximal convoluted tubules. Shih Tzu showed chronic nephritis with nephrosclerosis displaced by fibrous connective tissue in most areas. The glomeruli had undergone all stages of variation such as degeneration and fibrosis.

유성관광특구의 관광객 유치 촉진방안에 관한 연구

김시중,김희정,최지영 우송대학교 1999 우송대학교 논문집 Vol.4 No.-

The Korean Government has designated Yousung area as a tourism special district for promoting tourists' visitation. Unfortunately, since then, number of foreign visitors and domestic visitors has decreased gradually, except the years of 1994 and 1995. The purpose of this study is to find the current problems which the district has and develop strategies for promoting tourists' visitations. The study found three problems related to the district: 1) lack of sign boards and advertisements, 2) lack of events such as cultural events, art events and sport events and 3) lack of regional and central government supports. Three strategies could be recommendable for this district: 1) developing tourism routes for linking it to other tourist destinations, 2) improving overall service quality, and 3) loosening governmental restrictions.