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허성관,장영균,권택진 大邱大學校 科學技術硏究所 1998 科學技術硏究 Vol.5 No.3
Current industrial infrastructure has some drawbacks such that the effort for the efficiency of the facilities, most of which are imported, increase the cost of manufacturing. the special types of valves have been imported since the performance and the functional requirements are satisfied by the home products. Actually, the local products of the valve can be used only 1,000m Aq of lower pressure. On this paper, we develop the high pressure divert valve, which can be born the pressure of 3,000mm Aq. This development can contribute to the reduction of the cost and the increase of export.
In vitro skin permeation of cubosomes containing triclosan
Taek Kwan Kwon,Sung Kyeong Hong,김진철 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.1
Monoolein (MO) cubosomes containing triclosan (TCA) were prepared by micronizing MO cubic phases containing TCA in a bath-type sonicator. Pluronic F127 was used as a dispersant and no cubosomes could be produced from monoolein alone in the absence of the dispersant. The maximum tolerable ratio of TCA to MO for the formation of cubic phase was 16:84 (w/w). According to TEM photos and size distributions,the sizes of cubosomes were hundreds of nanometers. Using hydroxypropyl-b-cyclodextrin as a solubilizer for TCA, the in vitro skin permeation of TCA loaded in cubosomes was investigated on a diffusion cell. Even though the concentrations of TCA were the same in the suspensions of cubosomes, the skin permeations were increased more when the ratios of TCA to MO were higher in the cubosomes. Moreover, the permeations were higher than those of TCA suspension in aqueous solution of ethanol or propylene glycol.
권택관(Taek - Kwan Kwon),정용호(Yong-Ho Chung) 호서대학교 공업기술연구소 2023 공업기술연구 논문집 Vol.42 No.2
각국의 환경문제 및 규제 관련 대응에 따라, 최근 수소충전소와 수소전기차의 보급이 급격히 가속화되고 있다. 그동안 수소전기차의 보급 확대를 저해하는 요소로는 고가의 촉매를 사용함에 따른 연료전지 스택의 높은 단가문제도 그 중에서 하나로 지적되고 있었다. 다양한 합금기술을 통해 연료전지 스택에 촉매로 활용되는 백금의 효율을 향상시켜 상당부분 사용량 저감을 달성할 수 있었으나, 아직까지는 장기 안정성 측면에서 백금을 대체할 수 있는 촉매가 개발되지 못한 상황이다. 또한 수소전기차 보급 후 상당한 시간이 지나고 있으며, 사용연한이 만료되어 폐기되는 수소연료전지차도 발생되고 있는 상황이다. 따라서 연료전지 스택의 촉매로 활용되는 백금의 회수 및 재활용은, 연료전지의 가격 경쟁력을 향상시킬 수 있으며, 자원 재순환에 따른 환경문제 해결에도 도움이 될 수 있다. 본 연구에서는 최근 진행되고 있는 폐촉매 회수에 관한 기술 동향에 대해서 개괄하도록 하겠다. In response to each country's environmental issues and regulations, the spread of hydrogen charging stations and hydrogen electric vehicles has recently been rapidly accelerating. The high unit cost of the fuel cell stack due to the use of expensive catalysts has been pointed out as one of the factors hindering the expansion of hydrogen electric vehicles. Through various alloy technologies, it has been possible to improve the efficiency of platinum, which is used as a catalyst in fuel cell stacks, and achieve a significant reduction in usage, but a catalyst that can replace platinum in terms of long-term stability has not yet been developed. In addition, a considerable amount of time has passed since the dissemination of hydrogen electric vehicles, and hydrogen fuel cell vehicles are being discarded due to expiration of their useful life. Therefore, recovery and recycling of platinum, which is used as a catalyst in fuel cell stacks, can improve the price competitiveness of fuel cells and can also help solve environmental problems caused by resource recycling. In this study, we will provide an overview of recent technological trends related to waste catalyst recovery.
국소성 뇌경색에 미치는 고혈당의 영향에 대한 실험적 연구
권택현,박윤관,정용구,정흥섭,서중근,이훈갑,주정화,이기찬 대한신경외과학회 1992 Journal of Korean neurosurgical society Vol.21 No.1
The present study was undertaken to investigate the influence of hyperglycemia on focal cerebral ischemia in view of morphometric assay and neuropathological examination. Forty Sprague-Dawley rats were divided into two groups of 20 each Rat MCA occlusion model was used for induction of focal ischemia. Hyperglycemia(20 rats, mean±SEM plasma glucose concentration 378±97.6㎎/㎗) was established 30 minutes before MCA occlusion by intraperitoneal injection of 50% dextrose in water ; the control group(20 rats, mean±SEM plasma glucose concentration 121±24.9㎎/㎗) received normal saline only. Twenty-four hours after MCA occlusion neutral red staining and perfusion fixation was performed and ischemic area were measured using computerized image analysis on cortical surface and coronal cut surface. There was no signifcant difference on coronal cut surface, but on cortical surface showed increase of non-stained area(infarct core) and decrease of lightly stained area(transitional zone) in hyperglycemic rats(p<0.05) and the sum of two area was not different between two groups. Pathological findings were evaluated under light microscopy, in which the field scanning was carried out from the midline by 0.5㎜ interval at cortical and basal ganglia level. There showed no significant difference at basal ganglia level, but at cortical level ischemic transitional zone was decreased in hyperglycemic rats(p<0.05). We conclude that hyperglycemia may worsen the brain from severe, focal ischemic neuronal damage.
뇌경색후 Lipid Peroxidation에 미치는 Allopurinol 및 Deferoxamine의 효과에 대한 실험적 연구
권택현,박윤관,정용구,정흥섭,서중근,이훈갑,주정화,이기찬 대한신경외과학회 1992 Journal of Korean neurosurgical society Vol.21 No.1
It has been hypothesized that ischemia, followed by reperfusion, facilitates peroxidative free radical chain process in brain. This study was undertaken to investigate the effect of allopurinol and deferoxamine on cerebral lipid peroxidation, estimated by a thiobarbituric acid test, following transient bilateral forebrain ischemia in the rat model of four vessel occlusion. Sprague-Dawley rats fed ad libitum were subjected to transient but severe forebrain ischemia by permanently occluding the vertebral arteries and 48 hours later temporarily occluding the common carotid arteries for 20minutes. Carotid artery blood flow was restored and rats were decapitated after 48 hours. We assessed the lipid peroxidation capacity of cerebral homogenates obtained from hippocampus, basal ganglia, cortex and thalamus. The homogenates were subjected to 30 minutes of aerobic incubation. The production of lipid peroxides were decreased in all sampled area in the treated groups compared with the control group. Allopurinol and deferoxamine-treated groups showed decreased lipid peroxide levels in all the sampled area, but especially more in the hippocampus, (p=0.02), (p<0.01) repecxtively. Combined group (allopurinol and deferoxamine) showed decreased lipid peroxide levels in all the sampled area, but was not statistcally significant(p>0.05). The results suggest that allopurinol and deferoxamine play a role in protecting ischemic cellular damages by scavenging free radicals and subsequently lipid peroxides formed by oxygen supply through blood reperfusion.
권정택,황성남,박관,최덕영 대한신경외과학회 1993 Journal of Korean neurosurgical society Vol.22 No.8
A 62-year-old woman, who presented with dipolipia, was found to have a giant aneurysm of the right internal carotid artery. Gradual ligation of the right internal carotid artery was followed by nausea and vomiting 10 days after the complete ligation. Follow up MRI showed intraluminal thrombus formation of the aneurysm and right temporo-occipital infarction.
권정택,박관,김영백,민병국,황성남,석종식,최덕영 대한신경외과학회 1992 Journal of Korean neurosurgical society Vol.21 No.9
A retrospective analysis of 219 mild head injured patients who were admitted to Chung-Ang University Hospital from January 1990 to December 1991 was made to correlate outcome to initial Glasgow coma scale(GCS) score, combined injuries and radiologic findings. The results were as follows : 1) The young males were most frequently affected. 2) The most common cause was motor vehicle accident followed by fall. 3) The most common combined injury was cervical sprain followed by subgaleal hematoma. 4) The skull fractures were shown in 29.2% but there was no correlation between outcome and skull fracture. 5) The most common abnormal CT finding was the subdural hematoma(20.3%). 6) The positive blood alcohol test was not correlated with the outcome. 7) The majority of the patients(91.8%) made a good recovery. 8) Thirteen patients(5.9%) were performed cranial operation under the diagnosis of epidural hematoma(5 patients), subdural hematoma(4 patients), contusion and FCCD.