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도로터널에서 제트팬 근처의 재순환유동과 연기 역류현상의 상호작용 분석
김창균,유진웅,김성준 江原大學校 産業技術硏究所 2005 産業技術硏究 Vol.25 No.A
A numerical analysis was done for a tunnel fire in a 1000m road tunnel. A cartesian coordinate was adopted to make a computational grid sytem which has 448,000 computational cells. A transient flow phenomena in the tunnel was simulated by the commercial code of PHEONICS from the ignition of fire to 600 seconds by the interval of 100 seconds. Total computational time of about 44 hours was required to get a convered solution in each time step. The purpose of this research is to analyze of the backlayering pheonomena and recirculation flow in a tunnel. The compuational results say that the backlayering does not happens near the fire of vehicle in this case because the vehicle fire is located at the outside of recirculation zone of flow ocuured near the jet fan. In this research, onset of backlayering pheonomena could be escaped if jet fan is set 95m in front of the the fire of vehicle.
金昌均 高麗大學校 倂設 保健大學 保健科學硏究所 1999 보건과학 학술 세미나 Vol.- No.7
방사선과 방사능은 우리의 생활환경과 몸속에도 항상 존재하고 있고 또 이와같은 방사선은 항시 위험성을 내포하고 있어 원하든 원하지 않든 우리는 방사선의 피폭 위험성으로부터 완전히 자유로울 수는 없다. 그러나 우리의 관심과 노력 여하에 따라서 방사선의 피폭량을 줄일 수 있으며 지금까지 알려진 가장 기본적인 방법은 다음과 같다. 1) 방사선의 조사시간 또는 피폭시간을 줄임으로써 피폭량을 멸소시킬 수 있다.(Time). 2) 방사선이 나오는 장소로부터 멀리 떨어짐으로써 피폭량을 멸소시킬 수 있다.(Distance). 3) 방사선이 나오는 장소와 사람 사이에 어떤 물체를 놓음으로써 피폭량을 멸소시킬 수 있다.(Shielding). 한편 오늘날 ICRP에서는 방사선의 방어를 위해서 끊임없는 연구결과를 권고안으로 발표하고 있는데 지금까지 사용되고 있는(1990년도 발표) 권고안중 가장 핵심적인 내용은 방사선 방어제도(The system of radiological protection)로서 다음과 같다. 1) 방사선의 조사행위는 확실한 이득이 있을 때만이 가능하다. 2) 방사선의 조사는 사회경제적인 고려를 하여 합리적으로 달성할 수 있는 한 적게 해야 한다. 3) 방사선의 조사는 ICRP에서 권고하고 있는 한도를 초과하지 않도록 한다. 현재 ICRP에서는 방사선 작업종사자의 전신에 대한 방사선 피폭 허용한계를 5년간 평균하여 1년에 20 mSv, 그리고 일반인에 대해서는 5년간 평균하여 1년에 1 mSv로 권고하고 있으며 이 수치에는 background방사선은 포함되나 의료피폭의 방사선은 제외하고 된다. 그러나 방사선 방어의 역동적인 성질, 새로운 방사선 이용 행위의 전망, 그리고 방사선위험에 대한 일반인들의 변화하는 태도 때문에 방사선에 대한 확실한 보장과 비용-효과적 방어(cost-effective protection)를 위해서는 유관분야와 방사선전문가의 지식은 물론이고 축적된 경험이 중요하다. 방사선으로부터 우리의 안전(자신과 후손)을 지키기 위해서는 현재의 지식과 경험으로써는 위에 제시한 권고안이 최선이 될 수 있으나, 앞으로 생활의 환경과 방사선의 이용이 급격하게 변화되면 또 다시 새로운 권고안이 제시될 것으로 사료된다.
金昌均 高麗大學校 倂設 保健大學 保健科學硏究所 1992 保健科學論集 Vol.18 No.1
This study was carried out to investigate the radiation exposure dose to patient(adults) in head P-A projection, bas on e 66 hospitals located in Seoul. As a result, the following conclusions have been reached : 1. 68.18% of the surveyed hospitals made use of 70∼79 kVp(M±SD : 72.62±5.48 p) as tube voltage. 2. As tube current, 81.82% of the surveyed hospitals had the use o± 40∼69 mAs(M±SB : 50.7±14.9 mAs) . 3. Shallow equivalent doses ranged from 2.00 mSv to 3.99 mSv and the mean was 3.02 mSv.
金昌均,許俊 高麗大學校 倂設 保健大學 保健科學硏究所 1979 保健科學論集 Vol.10 No.1
In X-ray diagnosis, the scattered rays exert an evil influence upon X-ray film quality control and X-ray film finding. Therefore, many users of X-ray are not sparing of these labor to get rid of the scattered ray originated from the objects. These scattered rays were primarily influenced by the thickness of objects and the applied tube voltage. Authors made a study on the scattered ray dose to be influenced by the tube voltage and the object, and we obtained the results as follows; 1. Every objects play an important role as the scatterer in thin objects, but the other hand they function as the absorber in thick objects under a fixed tube voltage. 2. Every objects have the maximum build up points of the scattered ray under a fixed tube voltage. 3. The scattered X-ray were more influenced by the tube voltage than the thickness of object.
金昌均 高麗大學校 倂設 保健大學 保健科學硏究所 1987 保健科學論集 Vol.15 No.1
Various hazards by radiation exposure depend mainly on absorbed radiation dose. Author carried out this study in order to investigate the radiation absorbed dose percentage to patient in chest radiography with Mix-DP, tissue equivalent material, and following results were obtained 1. In 60kvp, radiation absorbed dose percentage was between 93.1% and 90.6%. 2. In 80kvp, radiation absorbed dose percentage was between 88.9% and 86.7%. 3. In 100kvp, radiation absorbed dose percentage was between 86.9% and 83.4%. 4. In 120kvp, radiation absorbed dose percentage was between 83.1% and 81.2%.
放射線遮蔽物質에서 附加濾過가 散亂線發生에 미치는 影響의 硏究
金昌均,許俊 高麗大學校 倂設 保健大學 保健科學硏究所 1980 保健科學論集 Vol.11 No.1
Exposure of scattered x-rays, at 135' and a distance of 1 m from the central ray of the primary beam, was measured at the back of all radiation shielding materials. Cement brick. Fire brick-red color, Fire brick-black color and Lead plate, for a 30×30㎝ field size. Scattered x-rays were measured from 125 to 200 kvp for 0-2mm Cu+1㎜Al added filter in the primary beam for an x-ray deep therapeutic unit, and obtained the results as follows: 1. The ability to absorb the radiation of the shielding materials were greatly depended on the used added filter. 2. The quantity of produced scattered x-rays had an influence upon the used added filter. 3. The rate of the scattered ray increase was carried away by the tube voltage and the used added filter.
김창균,최종학,김성환,최원의,최승환 高麗大學校 倂設 保健大學 保健科學硏究所 2000 保健科學論集 Vol.26 No.1
The results for a dose calibrator to measure the quantity of radionuclide are as follows; 1. Preciseness ; the value satisfied a permitted limit(±5%). 2. Accuracy ; the value was in the range of the permitted limit that is demanded from the manufacture. It might be because of the radiation that used corrected source of low dose. 3. Reliability ; Though the values for 2 months were in the range of ±5%, 2 days' values were beyond the range of -5%.
金昌均,李海龍,許俊 高麗大學校 倂設 保健大學 保健科學硏究所 1976 保健科學論集 Vol.7 No.1
Authors surveyed 68 units of diagnostic x-ray apparatus in Seoul area. The main purpose of this survey was to find out the protection problems in x-ray apparatus, especially, in the aspect of leakage ray from x-ray tube housing. As the result of this survey, the following conclusions were obtained. 1. In beam alignments, small capacity x-ray equipment (less than 60mA) were in generally used cone and large capacity machines in use were collimator. 2. Cones were too big in size and the materials were lack in thickness for its standard. Therefore, the function and role of the cone was not adequate. 3. Added filters used in beam were thin material for their tube voltage. 4. Leakage ray from x-ray tube housing in majority of domestic produce apparatus exceeds, the dose limit.