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고속 단발 가시화 스파크 점화 엔진에서의 연소 특성에 대한 선회효과 연구
김성수(Seong-Soo Kim),이귀영(Kwi-Young Lee),김승수(Sung-Soo Kim) 한국자동차공학회 1994 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The effects of swirl on early flame development and late combustion characteristic were investigated using a high speed single-shot visualized SI engine. LDV measurements were performed to get better understanding of the flow field in this combustion chamber. Spark plugs were located at half radius (R/2) and central location of bore. High speed schlieren photographs at 20,000 frames/sec were taken to visualize the detailed formation and development of the flame kernel with cylinder pressure measurements.<br/> This study showed that high swirl gave favorable effects on combustion-related performances in terms of the maximum cylinder pressure and flame growth rate regardless of spark position. However,at R/2 ignition the low swirl shown desirable effects at low engine speed gave worse performances as engine speed increased than without swirl. There were distinct signs of slow-down in flame growth during the period when the flame front expanded from 2.5 mm in radius until it reached 5.0 mm apparently due to the presence of ground electrode. There seemed to be heat transfer effect on the flame expansion speed which was evidenced in high swirl case by the slowdown of the late flame front presumably caused by relatively large heat loss from burned gas to wall compared with low- or no-swirl cases.<br/>
기준 슬립 발생기 및 적응 슬라이딩 모드 기법을 이용한 철도차량 제동력 제어
임태형(Tae Hyeong Lim),김승수(Seong Soo Kim),최정주(Jeong Ju Choi),이병룡(Byung Ryong Lee),양순용(Soon Yong Yang) Korean Society for Precision Engineering 2007 한국정밀공학회지 Vol.24 No.5
In the braking of railway rolling stock, the slip that is the relative velocity between train body and its wheel affects the adhesive force which is connected to the braking force. The coefficient of the adhesive force changes in accordance with the slip and the condition of a rail road. Namely, its value increases upon the maximum on a rail condition, and there it declines conversely while the magnitude of slip keeps rising on. First, this paper introduced a reference slip generator so that can utilize maximum adhesive forces with a disturbance observer for estimating unmeasurable current adhesive forces which is as an input of the generator. And, an adaptive sliding-mode control system has been synthesized for minimizing the error between reference and current slip. Finally the effectiveness of the proposed control system is evaluated by computer simulation.
$^{18}F$-FDG PET/CT 검사에서 신장 방사능의 효과적인 배설 방법에 관한 연구
김성수,김종철,신용철,이선도,이남주,김승수,이춘호,Kim, Seong-Su,Kim, Jong-Cheol,Shin, Yong-Cheol,Lee, Sun-Do,Lee, Nam-Ju,Kim, Seung-Soo,Lee, Chun-Ho 대한핵의학기술학회 2010 핵의학 기술 Vol.14 No.2
FDG PET/CT 검사에서 FDG는 신장 및 요료계를 통하여 배설된다. 이 방사능의 배설을 촉진 시키는 방법을 비교 및 분석하여 각 의료기관의 실정에 맞는 방법을 선택하는데 도움을 주고자 한다. 8개월간 본원에서 PET/CT 검사를 시행한 환자 중 신장에 병적 병변이 없고 기능이 정상인 환자 총 30명을 대상으로 하였다. FDG-PET/CT 기본검사를 마친 환자들을 무작위로 10명씩 다음 세 집단으로 나눠 지연검사를 촬영하였다. (1) 1시간 대기한 집단(Delay group), (2) 수분을 약 700 mL 섭취한 후 1시간 대기한 집단(Hydration group), (3) 이뇨제를 정맥주사하고 30분 대기한 집단(Lasix group). 평가는 육안평가와 정량분석을 하였다. 육안평가는 기본검사와 비교하여 각 집단별 지연검사 영상에서 신장의 방사능 배설을 네 단계로 나누어 비교 및 분석하였다. 정량분석은 기본검사의 표준화섭취계수에서 지연검사의 표준화섭취계수의 감소율을 측정하여 신장 방사능의 배설률로 활용하였다. 육안평가상 Lasix group이 가장 배설이 잘 되었고 그 다음은 Hydration group이었다. Delay group은 효과적인 배설이 이루어지지 않았다. 정량분석 결과 신장방사능 배설률은 Delay group $9.2{\pm}20.7%$, Hydration group $28.1{\pm}22.8%$, Lasix group $29.5{\pm}23.1%$이었다. Delay group과 Hydration group간, Delay group과 Lasix group간의 배설률은 통계적으로 유의한 차이를 보였다. Hydration group과 Lasix group간은 유의한 차이가 없었다. 본 연구에서 이뇨제를 사용하는 것이 신장의 방사능 배설을 촉진시키는데 가장 효과적임을 확인할 수 있었다. 또한 수분을 섭취하는 방법도 비슷한 효과를 보였으며 수분 섭취 없이 지연영상을 얻는 것은 효과가 없음을 확인 하였다. 이상의 방법들을 각 의료기관 실정에 맞게 적용함으로써 영상의 질 향상에 도움을 줄 수 있을 것이다. Purpose: Renal excretion is the main route of FDG clearance in FDG PET/CT scan. Applying optimal method of renal excretion is very important for enhancing image quality and diagnostic accuracy. We evaluated several methods of renal excretion in FDG PET/CT scan. Materials and Methods: Thirty patients with normal renal function were prospectively included. Patients were divided into three group and undergone early and delayed FDG PET/CT scans. (1) Delay group; at 1 hour later of early scan, delayed scan was performed without additional hydration, (2) Hydration group; at 1 hour later of early scan, delayed scan was performed with additional oral hydration (700 mL of water), (3) Lasix group; lasix was administered at the end of early scan and dealyed scan was performed 30 min later. Early and delayed scans were compared to evaluate efficiency of renal excretion. Visual and quantitative analyses were performed by experienced physician and technologist of nuclear medicine. Results: On the visual analysis, renal excretion was the most evident in Lasix group followed by Hydration group. Delay group showed poor renal excretion. On the quantitative analysis, washout rates were $9.2{\pm}20.7%$, $28.1{\pm}22.8%$ and $29.5{\pm}23.1%$ for Delay, Hydration and Lasix groups, respectively. Conclusion: Administration of lasix was the best method for enhancing renal excretion. Delayed scan with hydration was also efficient method, but delayed scan without hydration was not adequate method.
Enflurane 마취 및 수술침습(手術侵襲)이 갑성선기능에 미치는 영향
김승수,김동국,박정훈,김성덕,박득수,정종달 대한마취과학회 1982 Korean Journal of Anesthesiology Vol.15 No.2
This study was performed to investigate the effects of enflurane anesthesia and surgery on thyroid function by determining the plasma concentration of thyroxine (T4) and triiodothyronine (T3) in 10 patients who had neither hepatic disorder nor endocrine disease. Each patient was premedicated with diazepam 10 mg and atropine sulfate 0.5 mg intramuscularly on hour before induction of anesthesia. Anesthesia was induced with pentothal sodium and maintained with enflurane and oxygen supplemented with pancuronium bromide in divided doses as needed. Plasma concentrations of thyroxine and triiodothyronine were measured by means of radioimmunoassay. The results obtained were as follows; 1) No significant change in the plasma concentration of thyroxine was detected during enflurane anesthesia and surgery. 2) Plasma concentration of triidothyronine decreased significantly, compared with the control level, during enflurane anesthesia alone and anesthesia plus surgery. Although the precise mechanisms for the decrease in triiodothyronine following anesthesia and surgery remain unknown, decreased peripheral conversion from T4 to T3 may be responsible for this decline. Our data imply that enflurane anesthesia did not stimulate thyroid function judged by plasma concentration of T4 or T3. Therefore, enflurane anesthesia may be an useful anesthetics for patients with hyperthyroidism.