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김건희,김효식,양순철,이상용,국명호,이선규,김윤중,홍권희 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-
This paper describes development of low cost precision machine that has combined the Build-in Motor with a vacuum chuck. This study mainly aims to find out a cutting condition for maintaining optimum surface condition and to examine cutting characteristics of the precision machine that is equipped by diamond bites. The cutting materials is Al alloy. Several experiments were carried out to find out the main factors that affect the surface roughness such as principal axis RPM(rotation per minute), feeding speed, and cutting depth. As a result, we obtain The optimum cutting condition of the developed precision machine.
전자토모그래피의 정량적 분석에서 대물렌즈 조리개의 영향
김진규,이상희,권희석,정종만,정원구,이수정,주형태,김윤중 韓國電子顯微鏡學會 2008 Applied microscopy Vol.38 No.4
Electron tomography의 정량적 분석을 위해서 대물렌즈 조리개가 투과빔의 강도에 미치는 영향을 평가하였다. Electron tomography에 도입되는 Beer’s law의 올바른 적용을 위해서는 투과빔은 시료의 기울기에 따른 mass thickness의 변화에 의한 효과만을 반영해야 한다. 그러므로 빔 경로상의 대물렌즈 조리개, 홀더 등에 의한 다른 효과는 제거되어야 한다. 본 연구에서는 대물렌즈 조리개의 cut-off 효과를 120 kV TEM과 Quantifoil holey 카본 시료를 이용하여 상세히 평가하였다. 대물렌즈 조리개를 사용하지 않은 경우와 비교할 때, 30 μm 크기의 대물렌즈 조리개를 통과한 투과전자빔의 강도는 약 16.7%의 감소가 일어난다. 또한 55˚이상의 고경사각 기울기에서는 대물렌즈 조리개의 cut-off 효과에 의해 14.2%의 강도 감소가 추가적으로 발생함을 알 수 있었다. Electron tomography에서 정량적 분석을 위해서는 이러한 대물렌즈 조리개의 영향을 고려해야만 한다. 또한 Beer’s law의 올바른 적용을 위해서는 일련의 기울기에 따른 2차원적 영상은 가능하면 대물렌즈 조리개를 사용하지 않은 상태에서 획득하는 것이 바람직하다. We have evaluated the effects of experimental factors on transmitted electron beam intensities for quantitative analysis in electron tomography. For the correct application of Beer’s law in electron tomography, the transmitted beam intensity should reflect the net effect of mass properties on beam path. So, the any other effects of the objective aperture and the specimen holder on beam path should be removed. The cut-off effects of objective aperture were examined using Quantifoil holey carbon film and a transmission electron microscope operated at 120 kV. The transmitted beam intensities with 30 μm objective aperture dropped about 16.7% compared to electron beam intensities without the objective aperture. Also, the additional losses of about 14.2% at high tilt angles were occurred by cut-off effects of the objective apertures. For the precise quantitative analysis in electron tomography, the effect of the objective aperture on transmitted electron beam intensities should be considered. It is desirable that 2-D tilt series images are obtained without the objective aperture for correct application of Bee’s law.
곽희로,권동진,김영찬 崇實大學校 生産技術硏究所 1994 論文集 Vol.24 No.-
This paper describes very fast rising high voltage pules generation using the traveling wave theory of the transmission line. This very fast rising high voltage pulse generator consists of a charging coaxial cable, a discharging switch, and a terminating resistance. The results of the study show that the rising time of pulses is very fast about 30 [nsec]. The length of the coaxial cable and the charging voltage can regulate the duration and the amplitude or the polarity of the pulse. In addition, rod to plane electrodes are suitable as a short switch and the overshoot of pulse was improved with the larger radius of the rod electrode.
위암 환자에서 절제된 림프절 수의 차이와 관련이 있는 인자
정귀애,박정희,변익건,김경종,장정환,김권천,민영돈 朝鮮大學校 附設 醫學硏究所 2004 The Medical Journal of Chosun University Vol.29 No.1
Purpose: By the definition of UICC TNM classification (fifth edition), the nodal stage of gastric cancer is based on the number of metastatic lymph nodes, which is influenced by the number of resected lymph nodes. And individual differences in the number of resected lymph nodes had been observed in patients with gastric cancer. The aim of this study is to verify the factors which are associated with the difference in the number of resected lymph nodes in patients with gastric cancer. Methods: We reviewed 613 patients with gastric cancer who underwent curative resection and D2 lymph node dissection with 15 or more resected lymph nodes. The number of resected lymph nodes was analyzed according to the characteristics of patients, the types of operation and prognostic factors of gastric cancer. Results: The mean number of resected lymph nodes per patient was 33.0 (median: 31.0, range: 15-88). The number of resected lymph nodes was significantly associated with the types of operation, the location and size of tumor, macroscopic types, depth of tumor invasion and the number of metastatic lymph nodes. Patient's age, gender and the histopathological finding's had no relationship with the number of resected lymph nodes. Conclusions: The number of resected lymph nodes from gastric cancer was different in each patient despite of same D2 lymph node dissection and it was associated with several prognostic factors of gastric cancer.
최은서,강길,박정희,장정환,김권천,김경종,민영돈 朝鮮大學校 附設 醫學硏究所 2004 The Medical Journal of Chosun University Vol.29 No.1
Currently, in the limited cases of early gastric cancer (EGC), endoscopic mucosal resection (EMR) is used for curative treatment. However, its completeness is still controversial. The purpose of this study was to review the suggested indications of EMR. We retrospectively analyzed 234 patients with EGC who underwent curative (RO) gastrectomy. The enrolled cases were further classified into mucosal and submucosal types, and mucosal EGC were further classified according to the size, gross type and histologic pattern. 133 patients had mucosal cancers and 101 patients submucosal. The overall incidence of positive lymph node was 14.1% (33/234), the incidence of mucosal cancer was 8. 3% (11/133), which was significantly lower than that of submucosal, 22% (22/101). Of 133 patients with mucosal EGC, 90 were smaller than 2㎝ in size and the incidence of lymph node metastasis was 5.6% (5/90), compared to 43 of larger than 2㎝ with the incidence of 14% (6/43). According to the gross type classification of mucosal cancer, incidence of lymph node metastasis in protruded type (EGC type Ⅰ, Ⅱa, Ⅰ+Ⅱa) was 15.4% (4/26), nat type(EGC type Ⅱb) 2. 9% (1/35), depressed type (EGC type Ⅱc, Ⅲ) 8.3% (6/72). Lymph node metastasis in differentiated type of mucosal cancer was 6.9% (5/72) and undifferentiatcd type 9.8% (6/61). In this study, there was no single indication free from lymph node metastasis, It is thought that the selection of EMR for the curative treatment of EGC should be considered carefully and more clinical studies with long-term follow up are necessary for EMR to be generally acceptable.
Kim, Yu-Ri,Kim, Ki-Nam,Park, Yoon-Hee,Ryu, Yeon-Mi,Sohn, Sung-Hwa,Seo, Sang-Hui,Lee, Seung-Ho,Kim, Hye-Won,Lee, Kweon-Haeng,Kim, Meyoung-Kon The Korean Society of Toxicogenomics and Toxicopro 2005 Molecular & cellular toxicology Vol.1 No.3
Recently, a large number of clinical experiments have shown that exposure of organic pollutants lead to various cancers through the abnormal cell growth. Environmental pollutants, such as 2, 3, 7, 8-Tetrachloro dibenzo-p-dioxin (TCDD) and polycyclic aromatic hydrocarbons (PAHs), are carcinogen and are known to cause the cognitive disability and motor dysfunction in the developing of brain. The effects of these pollutants on neurodevelopmental disorder is well established, but the underlying mechanism(s) and similarity of gene expression profiles in human brain tumors with organic pollutants still remain unclear. In this study, we first examined the gene expression profiles in glioblastomas compared with meningioma that are kinds of primary human brain tumor by using human cDNA microarray. The results of cDNA microarray analysis revealed that 26 genes were upregulated (Z-ratio>2.0) and 14 genes were downregulated (Z-ratio<-2.0) in glioblastoma compared with meningioma. From the altered gene patterns, mitogen-activated protein kinase (MAPK) signaling related genes, such as MAP2K3, MAP3K11 and jun activated domain binding protein, and transcription factors, such as UTF2 and TF12, were upregulated in glioblastoma. Also, we tried to investigate the relation between important genes up- and down-regulated in giloblastoma and various organic pollutants. Therefore, the identification of changes in the patterns of gene expression may provide a better understanding of the molecular mechanisms involved in human primary brain tumors and of the relation between gene expression profiles and organic pollutants in brain tissue.
Folded catadioptric panoramic lens with an equidistance projection scheme
Kweon, Gyeong-il,Kim, Kwang Taek,Kim, Geon-hee,Kim, Hyo-sik The Optical Society 2005 Applied Optics Vol.44 No.14
<P>A new formula for a catadioptric panoramic lens with an equidistance projection scheme has been derived. The fabricated lens has a field of view that is wider than that of any previously reported panoramic lens, and the nonimaged region near the back of the camera has a constant volume with zero angular extension.</P>