폐암의 임상적 고찰

이정철,이종태,김규태,Lee, Jeong-Cheol,Lee, Jong-Tae,Kim, Gyu-Tae 대한흉부심장혈관외과학회 1986 Journal of Chest Surgery (J Chest Surg) Vol.19 No.1

A clinical study was made on 72 cases of primary lung cancer operated in the department of thoracic & cardiovascular surgery, Kyungpook national university hospital from January 1975 to May 1985. The ratio of male to female was 13.4: I and mean age was 53. Histologically, squamous cell carcinoma comprised 72.2% of 72 operated cases. Before admission to our hospital, the erroneous diagnoses were made at local clinics on the 43 cases[59.7%] and a large percentage of them was diagnosed as pulmonary tuberculosis. And then, total of 56 cases received inadequate treatment or delayed the operation. For the location of the tumor, right to left ratio is 1.2:1 and the right upper lobe was most often involved [23.6%]. Operation was performed on the 72 cases and resection on the 59 cases[8.2%]. Postsurgical staging showed that stage III was found most frequently [59.4%] and T,N,M, was 28% of total cases. Two common surgical complications were bleeding in 7 and acute respiratory failure in 6 cases, and these 6 cases of acute respiratory failure were all died. On the basis of these experiences, we conclude that aggressive effort is needed for the early accurate diagnosis and adequate treatment of lung cancer.

실리콘 박막 태양전지 현황 및 전망

이정철,송진수,윤경훈,Lee Jeong-Cheol,Song Jin-Su,Yun Gyeong-Hun 한국전기전자재료학회 2006 전기전자재료 Vol.19 No.7

방사성 동위원소를 이용한 개심술 전후의 심실기능 변화에 관한 연구: ECG gated blood pool scan을 이용한 ejection fraction 검사

이정철,김규태,Lee, Jeong-Cheol,Kim, Gyu-Tae 대한흉부심장혈관외과학회 1986 Journal of Chest Surgery (J Chest Surg) Vol.19 No.1

Recently, radionuclide angiocardiogram is one of the most common procedure for assessment of ventricular performance due to its distinctive advantages such as safety, accuracy, and ease of repeated studies. Also, measurement and comparison between pre and postoperative left ventricular ejection fraction [LVEF] are meaningful for assessing the severity of myocardial damage which occurred during open heart surgery and the status of myocardial recovery. We obtained pre and post operative LVEF using radionuclide angiocardiogram on 30 patients composed of atrial septal defect, ventricular septal defect, cyanotic congenital heart disease, and valvular heart disease who undergone the open heart surgery from March to august 1984. The study revealed that ventricular septal defect and mitral valvular heart disease showed 8.1% and 6.2% decreases of postoperative LVEF, respectively. But, there are little increases of postoperative LVEF in the atrial septal defect and cyanotic congenital heart disease. In ventricular septal defect, each group of Qp/Qs over 2.0 and systolic pulmonary artery pressure over 50mmHg showed significant 17% and 14.7% decreases of postoperative LVEF, respectively. Considering the duration of the aortic cross clamping times and closing methods of VSD, each group of duration over 30 min. and of patch closure showed 13.9% and 14.2% decreases of LVEF between pre and postoperative status respectively which was significant finding statistically.

영상처리를 이용한 반복적 작업의 측정에 관한 연구

이정철,심억수,김남주,박찬권,박진우,Lee, Jeong-Cheol,Sim, Eok-Su,Kim, Nam-Joo,Park, Chan-Kwon,Park, Jin-Woo 대한산업공학회 2001 산업공학 Vol.14 No.1

Previous work measurement methods need much time and effort of time study analysts because they have to measure required time through direct observations. In this study, we propose a method which efficiently measures standard times without involvement of human analysts using digital image processing techniques. This method consists of two main steps: motion representation step and cycle segmentation step. In motion representation step, we first detect the motion of any object distinct from its background by differencing two consecutive images separated by a constant time interval. The images thus obtained then pass through an edge detector filter. Finally, the mean values of coordinates of significant pixels of the edge image are obtained. Through these processes, the motions of the observed worker are represented by two time series data of worker location in horizontal and vertical axes. In the second step, called the cycle segmentation step, we extract the frames which have maximum or minimum coordinates in one cycle and store them in a stack, and calculate each cycle time using these frames. In this step we also consider methods on how to detect work delays due to unexpected events such as operator's escapement from the work area, or interruptions. To condude, the experimental results show that the proposed method is very cost-effective and useful for measuring time standards for various work environment.

Hot Wire CVD법에 의한 수소화된 미세결정 실리콘(${\mu} c-Si:H$) 박막 증착

이정철,송진수,박이준,Lee, Jeong-Cheol,Song, Jin-Su,Park, Lee-Jun 대한전자공학회 2000 電子工學會論文誌-SD (Semiconductor and devices) Vol.37 No.8

열선 CVD(Hot Wire CVD)를 이용해 유리기판에 미세결정 실리콘(${\mu}c$ -Si:H) 박막을 증착시키고, 증착 조건에 따른 막의 특성변화를 관찰하였다. 열선 CVD법에 의한 ${\mu}c$ -Si:H막의 증착률은 조건변화에 따라 0.2nm/sec에서 3.5nm/sec사이의 값을 가졌으며, 기존의 PECVD법에 비해 10배 이상 높은 값이었다. Raman 특성으로부터 ${\mu}c$ -Si:H막은 비정질과 결정질의 두상이 혼합된 상태임을 알 수 있었으며, 평균 결정 립의 크기는 6-10nm, 결정체적분율은 37~63%범위였다. 막의 전도대와 Fermi 준위의 차를 나타내는 전도 활성화에너지(conductivity activation energy)는 30mTorr에서 0.22eV로 나타났으며, 압력에 따라 증가하여 300mTorr에서는 0.68eV의 값을 가졌다. 막의 활성화 에너지 증가는 높은 압력에서 증착된 막의 특성이 진성(intrisic)에 가까움을 의미하며, 이는 압력증가에 따른 암 전도도의 감소특성으로부터 확인할 수 있었다. 또한 이차이온질량분석으로부터 열선온도 1800$^{\circ}C$에서 증착시킨 막의 텅스텐 함유량은 $6{\times}10^{16}atoms/cm^3$임을 알 수 있었다. This paper presents deposition and characterization of hydrogenated microcrystalline silicon (${\mu}c$ -Si:H) films on low cost glass substrate by Hot Wire CVD(HWCVD). The HWCVD ${\mu}c$ -Si:H films had deposition rates ranging from 2${\AA}$/sec to 35${\AA}$/sec with the variations of preparation conditions, which was 10 times higher than that of the films obtained from the conventional PECVD method. From the Raman spectroscopy, the prepared silicon films were found to be composed of the mixture of crystalline and amorphous phases. The crystalline volume fraction and average crystallite size, obtained from the Raman To mode peak near 520cm$^{-1}$, were 37-63% and 6-10 nm, respectively. The conductivity activation energy($E_a$) of the ${\mu}c$ -Si:H films, representing the difference of conduction band and Fermi level in an intrinsic semiconductors, increased from 0.22eV to 0.68eV with increasing pressure from 30mTorr to 300mTorr. The increase of $E_a$ with pressure indicates that the deposited films have properties close to intrinsic semiconductors, which is also proved with low dark conductivity of the ${\mu}c$ -Si:H deposited at 300mTorr. The tungsten concentration incorporated into films was about $6{\times}10^{16}atoms/cm^3$ in the samples prepared at wire temperature of 1800$^{\circ}C$.

분쇄 방법 및 하소온도에 따른 Doner-doped BaTiO₃의 전기적 특성

이정철,명성재,전명표,조정호,김병익,신동욱,Lee, Jeong-Cheol,Myong, Seong-Jae,Chun, Myoung-Pyo,Cho, Jeong-Ho,Kim, Byung-Ik,Shin, Dong-Wook 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.3

In this study, We have been investigated the effect of calcination temperature and high-energy ball-milling of powder influences the $BaTiO_3$-based PTCR(Positive Temperature coefficient Resistance) characteristics and microstructure. The mixed powder was obtained from $BaCO_3$, $TiO_2$, $CeO_2$ ball-milled in attrition mill. The mixed powder was calcine from 1000 $^{\circ}C$ to 1200 $^{\circ}C$ in air and then it was sintered in reduction- re-oxidation atmosphere. As a result, The room-temperature electrical resistivity decreased and increased with increasing calcination temperature. specially, Attrition milled powder could have low room-temperature resistivity and high PTC jump order at 1100 $^{\circ}C$. attrition milling had lower room-temperature resistivity than ball milling. Particle size decreased by Attrition milling of powder influences in calcination temperature and room-temperature resistivity.

중ㆍ고령 건설근로자의 재해 분석

이정철(Lee Jeong-Cheol),신승우(Shin Seung-Woo),이찬식(Lee Chan-Sik) 대한건축학회 2007 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.27 No.1

The domestic average life span is increasing due to the growth of economy, society and the improvement of living standards. So the aging society is rapidly approaching in Korea. There is gradually increasing the number of senior people from 50 to 64 years old in total productive population. Especially, according to the increase of the middle and advanced age, accident rates of the middle & advanced-aged construction workers has considerably increased at the construction site. It has been analysed that the occurrence status of the total and fatality accident for each age group in construction field for 5 years. The results are as follows, the number of workers over 50 years old accounts for about 37 ~ 41 percent in total accident and about 41 ~ 47 percent in fatality accident. Those figures are much bigger than the other aged group. The research and analysis have been performed on the industrial accident status and cause of the middle & advanced-aged construction workers. This paper may provide useful information about appropriate disposition and safety precaution of the middle & advanced-aged construction workers.

제로샷 행동 인식을 위한 멀티모달 크로스 어텐션

이정철(Jeong Cheol Lee),이동규(Dong Gyu Lee) 한국통신학회 2023 한국통신학회 인공지능 학술대회 논문집 Vol.2023 No.9

공동주택 디자인 요소의 중요도 평가 연구

이정철(Lee, Jeong-Cheol),박석규(Park, Surk-Kyoo),김경배(Kim, Kyung-Bae) 한국주거학회 2021 한국주거학회 논문집 Vol.32 No.3

As apartments have recently become more advanced and diversified, the Government of South Korea has expanded the design guidelines of the Ministry of Land, Infrastructure and Transport, which used to be applied only to public apartments, to private houses since March 2010. In addition, local governments’ policies, such as “the Seoul Metropolitan Government’s Building Standards” and “Gyeonggi-do Apartment Design Standards”, are also moving toward emphasizing the quality of housing design. This study aims to find out what are the most important elements of the design of apartments and community facilities. As a result of conducting Focus Group Interview (FGI) to related experts, 6 items on the design elements of apartment, 29 items on detailed design elements, 5 items on community facility design and 17 items on detailed design elements were derived. An analysis of the importance in design elements showed that the number one design element of apartments is the interior design and which also shows that residents consider the space they own more important. The most important element of community facility design is the outdoor space and which is the most important for residents of residential complexes to have access to outdoor space for community exchange and bonding.

연구논문 : 패밀리 레스토랑 이용객의 선택요인 연구

이정철 ( Lee Jeong Cheol ),박정수 ( Park Jeong Su ) 관광품질시스템학회 2002 관광품질시스템연구 Vol.8 No.1