총경동맥 폐쇄시간에 따르는 국소 뇌혈류 변화 : 실험적 연구 An Experimental Cat Model

강준기,성태경,조병일,백민우,김문찬,허춘웅,하영수,송진언 대한신경외과학회 1983 Journal of Korean neurosurgical society Vol.12 No.3

The microvasculature of the brain is also quite susceptible to ischemic insult, and substantial portions of the brain are not reperfused after restoration of the blood supply following overtime of critical ischemic periods. The purpose of this series of experiments was to determine the effects of ischemia on subsequential regional cerebral blood flow measurements and cortical electric activities following reperfusion after ischemia and also to define the proper time of vascular occlusion without irreversible neural damage. Cerebral ischemia was induced in cat by bilateral common carotid occlusions for periods of 10, 30, to 60 minutes, and the blood supply was reperfused for 3 hours after clamp-off. Regional cerebral blood flow(rCBF) was measured by hydrogen clearance technique following ischemia, restoration of blood supply and electroencephalogram recovery could be predicted according to the rCBF. Forty adult cats weighing 2.7 to 4.0㎏ were used in this study. The animals were divided into 4 groups of 10 cats each : normal control, 10 min-clamped, 30 min-clamped, and 60 min-clamped groups. The results obtained were as follows : 1) The mean rCBF was 24.6±7.0㎖/100g/min in control group. 2) Bilateral carotid occlusions resulted in a reduction of the rCBF(12.4±4.1㎖/100g/min) to 50% of control flow on both hemispheres. 3) Sequential changes of the rCBF after reperfusion : (1) There was restored the rCBF(21.3±5.1㎖/100g/min) to control flow in the 10 minutes-clamped group. (2) There was a 85% recovery of control flow in the 30 minutes-clamped group. (3) There was a only 25% recovery of control flow in the 60 minutes-clamped group. 4) A close correlation was found between cortical electrical activity and rCBF suggesting a threshold relationship. (1) The changes of cortical electric activity began to notice at rCBF less than 17.4±4.7㎖/100g/min. (2) The recovery of cortical electric activity noted at rCBF more than 10.2±2.3㎖/100g/min. 5) There was no evidence of ischemic involvement at the cortex, white matter and basal ganglia in the 10 minutes clamped group, but demonstrated a dense wedge shaped infarct at the cortex and uncus herniation in the 60 minutes clamped group. The rCBF and cortical electric activity restored to normal values in reperfusion within 10 minutes after occlusion of both common carotid arteries.

민(MIN) 설계 방법을 이용한 무인기 수평이동제어 알고리즘에 관한 연구

왕현민(Hyun-Min Wang),허경무(Kyung-Moo Huh),우광준(Kwang-Joon Woo) 대한전자공학회 2009 電子工學會論文誌-SC (System and control) Vol.46 No.3

최근 무인기의 형태는 다양한 형태로 개발되고 있으며, 탑재 장비의 고성능 소형화를 바탕으로 무인기는 소형화 되고 있다. 이러한 소형화되고 일반적인 형태가 아닌 무인기 개발에 있어, 기존의 개발방법으로는 이러한 비선형적인 요소로 인하여 정확한 모델링 및 제어기 알고리즘의 정형화하기가 어렵다. 따라서 본 논문에서는 기존이 비행체 개발 방법이 아닌, 하중 제어 개념을 적용한 Min 설계 방법의 첫 번째 단계로, 원통형 무인기에 적용하여, 수평 비행 조건과 특성 그리고 제어기 설계 알고리즘을 찾아보았다. 이러한 Min 설계 방법은 고성능 컴퓨터를 사용한 무인기 개발에 있어 실시간 시뮬레이션을 통한 비용절감과 개발기간을 단축시킬 수 있다. Recently, UAV(unmanned aerial vehicle) has evolved into various figure and become miniaturized. On using existing design method, it is hard to make modelling and standardizing design of flight control system of the figure including cylinder like pipe. These problems are caused by uncorrect express of nonlinearity in controller design. Therefore, it is developed through step of correct modelling and simulation on real time using high efficiency computer in aircraft development of various figure. This is reducing period and expense of aircraft development. For the shake of solving these problems, Min-design method has been devised by H.M. Wang. In this paper, an object of control is cylindrical UAV instead of the general figure of aircraft. It was analyzed flight condition, specification about level flight of the UAV and was presented algorithm to find control value.

Deposition of SiCxNy Thin Film as a Membrane Application

Huh,Sung-Min(Sung-Min Huh),Park,Chang-Mo(Chang-Mo Park),Jinho Ahn(Jinho Ahn) 한국마이크로전자및패키징학회 2001 마이크로전자 및 패키징학회지 Vol.8 No.1

SiCxNy film is deposited by electron cyclotron resonance plasma chemical vapor deposition system using SiH_4(5% in Ar), CH₄ and N₂. Ternary phase SiCxNy thin film deposited at the microwave power of 600 W and substrate temperature of 700 contains considerable amount of strong C-N bonds. Change in CH₄flow rate can effectively control the residual film stress, and typical surface roughness of 34.6 (rms) was obtained. Extremely high hardness (3952 Hv) and optical transmittance (95% at 633 nm) was achieved, which is suitable for a LIGA mask membrane application.

비행 물체의 유도제어 시스템 설계를 위한 하중(중력수) 제어 모델의 성능분석

왕현민(Hyun-Min Wang),우광준(Kwang-Joon Woo),허경무(Kyung-Moo Huh) 대한전자공학회 2009 電子工學會論文誌-SC (System and control) Vol.46 No.1

기존의 방법에서는 비선형 운동 물체의 운동 방정식을 선형화하므로써 비행체의 운동 상태방정식을 구하고, 각 제어 기관에 따라 전달함수를 구하여 안정성 판별과 더불어 제어기를 설계하였다. 이러한 설계 방법으로는 일반적인 비행기와 같은 형태, 비행 환경이 급격하게 변하지 않고 속도가 빠르지 않는 비행체의 유도/제어기 설계에 많이 사용되어 많은 성능을 발휘할 수 있다. 그러나 이러한 설계 방법은 통상적이지 않는 비행체 형태뿐만 아니라 빠른 속도에서 급격한 움직임을 갖는 비행체에서는, 기존의 유도/제어기 설계 방법으로는 이러한 비선형성으로인하여 제어성(경로문제)과 안정성(안정화문제)을 동시에 충족할 만한 성능을 발휘 할 수 없다. 따라서 본 논문에서는 이러한 불확실성이 내포된 비행체 제어 문제에서 제어성과 안정성을 동시에 충족시키기 위한 과정 중 먼저 제어성 문제를 해결하기 위한 비행체 제어성을 분석하고 모델을 제시한다. 또한 본 논문에서 비행체 모델과 동역학 모델에서 제어 요소로서 하중(중력수)을 설정하고 비행 특성에 따른 제어요소 값을 살펴본다. 이것은 Min 설계 방법 1단계이다. In conventional method, flight model is discribed to differential equation by linealization of nonlinear object motion equation. As state equation from differential equation of moving object, the controller is designed by transfer functions of each module under discrimination of stability criteria. But this conventional method is designed under limitation of nonlinearity from object's shape and speed. In other word, The greater part of guidance/navigation system was satisfied with the result of good performance for normal figure of flight object, not sudden changed flight condition, not high speed. But it is not able to give full play to its ability on flight object which has abnormal figure, sudden changeable motion, high speed. Therefore, in this paper was presented performance analysis of load control model for navigation/guidance system on flying object being uncertainty, non-linear like abnormal figure, sudden changeable motion, high speed and is presented method of trajectory control(controllability) ahead of controllability and stability to achieve flight mission. In other word, this paper shows the first step of Min-design method and flight control model.

단신 : 실리콘의 염소화반응에 의한 사염화규소 제조

박균영 ( Kyun Young Park ),이미선 ( Mi Sun Lee ),김민철 ( Min Cheol Kim ),이찬희 ( Chan Hee Lee ),박회경 ( Hoey Kyung Park ),강태원 ( Tae Won Kang ),정해성 ( Hae Seong Jeong ),한경아 ( Kyoung Ah Han ),허원회 ( Weon Hoe Huh ),유지 한국화학공학회 2013 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.51 No.3

직경 25 mm의 파이렉스 튜브 내에서 실리콘의 유동층 염소화 반응이 수행되었다. 반응기에 공급되는 질소 유량0.8~1.0 L/min, 염소 유량 0.2 L/min, 반응온도 450℃, SiCl4 응축기의 냉매온도는 -5℃로 설정하였다. 반응기에 도입되는 가스 내 염소의 몰분율이 증가하면 SiCl4의 수율이 증가하였다. 반응가스 중 염소의 몰분율 0.2의 조건에서 SiCl4의 수율은 28% 이었다. 염소의 몰분율 증가는 반응열 상승에 의해 반응온도 상승을 가져옴으로써 안전을 고려하여 염소의 몰분율을 0.2 이상으로 올리지 못했다. 실리콘의 유동층 염소화 반응에 의한 사염화실리콘의 제조 가능성이 입증되 었으며, 향후 보다 가혹한 조건에서의 실용화 연구를 위한 기초로 활용될 수 있을 것으로 기대된다. The chlorination of a metallurgical-grade silicon was carried out in a fluidized bed reactor, 25 mm in diameter. The flow rate of the chlorine admitted into the reactor was 0.2 L/min and that of the carrier nitrogen was 0.8~1.0 L/ min. The reactor temperature was maintained at 450℃ and the temperature of the coolant at the SiCl4 condenser was at -5℃. The SiCl4 yield increased with increasing the mole fraction of chlorine in the feed gas, exhibiting 28% at the mole fraction of 0.2. Further increase of the chlorine mole fraction was not attempted in a worry that the reactor might be failed due to the high exothermicity of the reaction. The production of SiCl4 from silicon by fluidized bed chlorination was demonstrated on a laboratory scale, which is a stepping stone for future studies under more severe conditions toward industrial application.

Microfluidic generation of Prussian blue-laden magnetic micro-adsorbents for cesium removal

Kang, Sung-Min,Rethinasabapathy, Muruganantham,Hwang, Seung Kuy,Lee, Go-Woon,Jang, Sung-Chan,Kwak, Cheol Hwan,Choe, Sang-Rak,Huh, Yun Suk Elsevier 2018 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.341 No.-

<P><B>Abstract</B></P> <P>Here, we designed and synthesized a recoverable multifunctional adsorbent using a microfluidic reaction system and evaluated the removal performance of the smart adsorbent toward radioactive cesium as a model sample. Prussian blue-laden magnetic micro-adsorbents (PB-MNPs-MAs) with uniform morphology and monodispersity were generated via two-step sequential procedures using a glass capillary microfluidic system, followed by chemical co-precipitation with a high production rate. The cesium removal efficacy of the PB-MNPs-MAs was analyzed based on Langmuir and Freundlich isotherms by controlling adsorption parameters such as adsorbent size, initial cesium concentration, and contact time. The adsorption isotherm of the PB-MNPs-MAs was better fitted to the Langmuir model with a maximum cesium adsorption capacity of 58.73 mg g<SUP>−1</SUP>, which was 40% higher than that of macro-adsorbents in a dynamic magnetic field. This result can be attributed to their large specific area, which increased the kinetic rate of cesium adsorption and achieved saturation within 20 min. Additionally, the PB-MNPs-MAs were recovered from wastewater within 5 s under a static magnetic field, indicating their great potential for magnetic actuation. We believe that our PB-MNPs-MAs can encapsulate nano-functional adsorbents and prevent actuation, making them promising for environmental remediation and especially for removal of radionuclides.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PB-MNPs-MAs were generated in microfluidic device using chemical co-precipitation. </LI> <LI> The prepared PB-MNPs-MAs are monodispersed with uniform morphology. </LI> <LI> PB-MNPs-MAs exhibited high Cs adsorption capacity (58.73 mg g<SUP>−1</SUP>). </LI> <LI> 100% recovery of PB-MNPs-MAs is possible under static magnetic field after Cs adsorption. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

축분비료에 대한 수요반응과 이용 활성화 방안

허덕,정민국 한국농업정책학회, 한국축산경영학회 2001 농업경영정책연구 Vol.28 No.1

The objective of this study were to suggest the problem of livestock manure usage and the method to activate its demand in Korea. According to the result of farm survey, the main reason of low demand is that the cultivation farmers don't trust quality of livestock manure. To activate of livestock manure demand, quality of livestock manure is certificated. Consumers were willing to pay more than the current price of livestock manure if its quality certificated.

방사선치료와 화학요법을 받은 유방암 환자에서 발생한 발치 후 종창의 진단영상학적 감별 진단

허경회,안병모,김미자,박관수,허민석 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.36 No.3

A 60-year-old female, who complained of delayed healing and swelling after extraction of left lower second molar during chemotherapy, visited our department. She had a history of a resection surgery of breast cancer and postoperative radiotherapy. The conventional radiographs showed diffuse permeative bone destruction in posterior mandibular body, which gave the first radiologic impression of osteonecrosis associated with radiotherapy or chemotherapy. And bone metastasis from the breast cancer was also considered in the differential diagnosis. On the enhanced computed tomography (ECT) the posterior mandibular body was occupied by a large expansile lesion showing central low attenuation with peripheral rim enhancement. Magnetic resonance images revealed that the low attenuated area on ECT did not show as high signal intensity as water on T2 weighted image and indicated solid component of a tumor. The final diagnosis was central squamous cell carcinoma. We present the diagnostic imaging features of the patient with special emphasis on the differential diagnosis.

서귀포시 축산폐수의 발생특성에 관한 연구

허목,이용두,이민규 제주대학교 환경연구소 1993 환경연구논문집 : 제주대 Vol.1 No.-

As a part of basic investigation and research the present condition and characteristics of livestock wastewater production in Sogwipo City is accessed. Based on the current data a trend of the livestock wastewater production for the furture is predicted. This is our purpose to facilitate this report as a basic guide-line for the furture livestock wastewater treatment. The result of this study are summarized as follows : 1. Breeding households of livestocks (swine. beef cattle, chicken) decrease every year, but the number of heads per household are increased each year. 2. BOD-loading per day of beef cattles wastewaters investigated 59.2kg. and pollution loadings are suspected 38.3 BODkg/day at 2001 year. 3. The quanity of swine wastewaters were counted 12.4ℓ/head·day, BOD-loadings were reached 45.6kg and suspected same values at 2001 year

제주도 스코리아를 이용한 세라믹 타일의 연구

허민자 한국공예학회 2000 조형디자인연구 Vol.3 No.2

Scoria is a kind of pyroclastics. It is formed when magma becomes porous powder during volcanic activities. It is called by "song-i" in Cheju. Scoria is a good ceramic material since it shows good grindability due to a low level of organic impurities. This characteristic allows scoria to play a good role of airing when it is mixed with clay. In this study nature stone-textured ceramic tile was developed by mixing conventional clay with scoria which shows a tremendous amount of reserves in Cheju. Specifically, the ceramic tile was made of scoria sludge occurred at scoria brick factories, therefore, it will contributes to the decrease of production costs as well as to the environmental protection. I hope that the ceramic tile developed through this study provides a chance to contribute to keeping the tradition and regional identity of architecture in Cheju