Retroperitonal paraganglioma with huge uterine myoma : A case report

김국원,변상희,이함박,이대우 대한산부인과학회 2012 대한산부인과학회 학술대회 Vol.98 No.-

Paragangliomas are uncommon tumors arising from the neuroendocrine elements of the paraganglia and symmetrically distributed along the aorta in close association with the sympathetic chain. Although functional tumors are easier to diagnose due to the clinical findings caused by excess secretion of catecholamines and an elevation of the urinary catecholamine levels, however the diagnosis of nonfunctioning paraganglioma of the retroperitoneum is difficult and only few cases have been made before exploratory laparotomy. Surgical excision remains the mainstay of treatment, although advanced disease and proximity to vital organs can make excision difficult or impossible. This case report describes a patient who initially underwent work up for a huge multiple myomas of uterus and retroperitoneal mass which was discovered to be a retroperitoneal paraganglioma by frozen section. She is fortunate that the tumour did not show any features of malignancy nor metastasis, however a long time follow up is needed in case of any possible recurrence.

공구끝단반경이 고려된 2차원 금속절삭에 대한 열-점소성 유한요소해석

김국원,이우영,신효철,Kim, Kug-Weon,Lee, Woo-Young,Sin, Hyo-Chol 대한기계학회 1998 大韓機械學會論文集A Vol.22 No.1

In this paper, thermo-viscoplastic finite element analysis of the effect of tool edge radius on cutting process are performed. The thermo-viscoplastic cutting model is capable of dealing with free chip geometry and chip-tool contact length. The coupling with thermal effects is also considered. Orthogonal cutting experiments are performed for 0.2% carbon steel with tools having 3 different edge radii and the tool forces are measured. The experimental results are discussed in comparison with the results of the FEM analysis. From the study, we confirm that this cutting model can well be applied to the cutting process considered the tool edge radius and that a major causes of the "size effect" is the tool edge radius. With numerical analysis, the effects of the tool edge radius on the stress distributions in workpiece, the temperature distributions in workpiece and tool, and the chip shape are investigated.estigated.

A Numerical Analysis of Polymer Flow in Thermal Nanoimprint Lithography

김국원,김남웅,이우영 한국반도체디스플레이기술학회 2010 반도체디스플레이기술학회지 Vol.9 No.3

Nanoimprint lithography (NIL) is an emerging technology enabling cost effective and high throughput nanofabrication. To successfully imprint a nanometer scale patterns, the understanding of the mechanism in nanoimprint forming is essential. In this paper, a numerical analysis of polymer flow in thermal NIL was performed. First, a finite element model of the periodic mold structure with prescribed boundary conditions was established. Then, the volume of fluid (VOF) and grid deformation method were utilized to calculate the free surfaces of the polymer flow based on an Eulerian grid system. From the simulation, the velocity fields and the imprinting pressure for constant imprinting velocity in thermal NIL were obtained. The velocity field is significant because it can directly describe the mode of the polymer deformation, which is the key role to determine the mechanism of nanoimprint forming. Effects of different mold shapes and various thicknesses of polymer resist were also investigated.

53. 셀레늄함유 청보리 사일리지급여가 육성기 거세한우의 생산성 및 혈액성상에 미치는 영향

김국원,조익환,황보순,이성훈,한옥규,박태일,최인배 한국초지조사료학회 2012 한국초지조사료학회 학술대회논문집 Vol.2012 No.09

압축된 고무재료의 정적 변형 해석과 동특성 예측

김국원,임종락,손희기,안태길 한국소음진동공학회 1999 소음 진동 Vol.9 No.3

The effect of static preload on the dynamic properties of rubber materials is rather important, especially when good isolation characteristics are required at high frequencies. However, there are still few papers for dynamic characteristics of compressed rubber components. It was demonstrated in reference (4) that for bonded rubber material of a cylindrical shape, a simplified theory equation between linear dynamic and nonlinear static behavior of rubber material was useful to predict their combined effects. This paper presents the second part of the study. It is confirmed that for the compressed rubber material, the stress can be factored into a function of frequency and a function of strain(stretch). The finite element methodis applied to analyze non-linear large deformation of rubber material and its results are compared with those of a simplified theory equation. The predicted dynamic material properties based on non-linear static finite element analyses have a good agreement of experimental results and those based on simplified theory equation.

생식내분비학 : di-2-ethylhexyl phthalate 가 인간 자궁내막암세포주에서 세포주기의 변화에 미치는 영향

김국원,김미란,김장흡,조현희 대한산부인과학회 2012 대한산부인과학회 학술대회 Vol.99 No.-

목적: 프탈레이트는 다이옥신이나 비스페놀과 마찬가지로 잘 알려진 내분비교란물질이다. 남성에서 프탈레이트는 hypospadias, cryptorcidism, testicular cancer, decreased semen quality 등을 유발하는 것으로 알려져 있으나 여성에서의 영향은 크게 알려져 있지 않다. Davis 등은 프탈레이트가 난포의 정상적인 배란주기에 영향을 주어 무배란 주기를 만들어내어 다낭성 난소증후군의 원인이 된다고 주장한 바 있으며, 여러 epidemiological data 를 보면 프탈레이트 조산, premature breast development, 자궁내막증 등 여러 산부인과 질환과 연관성이 있다. 다낭성 난소증후군의 경우, 에스트로겐의 영향으로 자궁내막에 동반 질병이 발생할 수 있는데, 대표적인 질환이 자궁내막증식증과 자궁내막암이다. 자궁내막증식증은 자궁내막 세포가 비정상적인 증식을 보이는 질환으로, 자궁내막암과는 달리 invasion 이나 metastasis 는 되지 않는다. 이 두 질환, 그리고 프탈레이트와 연관성이 의심되는 자궁내막증은 모두 자궁내막세포의 세포주기에 이상 형태를 보이는 공통점이 있다. 자궁내막증은 자궁내막세포가 자궁내막 이외의 장소에 이소성으로 존재하면서 이상증식을 보이는 질환이다. 자궁내막증에서 나타나는 이소성 자궁내막조직은 정상적인 면역과정에서 제거되지 않는 immune survailence를 보이면서 증식하는 특징을 가지고 있다. 이에 저자들은 자궁내막암 세포주를 이용하여 프탈레이트에 노출된 후 세포주기에 어떠한 변화를 보이는지를 확인하고자 마이크로 어레이를 이용한 본 연구를 준비하였다. 방법: 1. 인간자궁내막암 세포주의 배양 2. 자궁내막암 세포주를 50 μM의 디에틸헥실프탈레이트(di-(2-ethylhexyl) phthalate : DEHP)에 48시간 동안 노출 3. RNA 추출 4. GeneChip® Human Genome U133 plus 2.0 Arrays (Affymetrix, Santa Clara, CA)을 이용한 microarray 시행 : 증폭된 유전자의 발현 확인 5. 정량 실시간 중합효소연쇄반응(quantative real-time polymerase chain reaction :qRT-PCR) 으로 정량적 확인 6. FACS analysis를 이용한 세포주기 분석. 결과: two fold change 를 기준으로 하였을때 총 522개의 유전자가 up regulated 되었으며, 375개의 유전자가 down regulation 되었다. 세포사망, 지질대사, gluconeogenesis, reponse to hormone stimulus 와 관련되 ㄴ유전자들이 up regulated 되고, mitosis, meiosis, DNA damage check point, reproductive development 등과 관련된 유전자들은 down regulation 되었다. KEGG pathway analysis 에서는 MAPK, VEGF, P53, mTOR pathyway 등이 up regulated 되었으며, cell cycle, oocyst meiosis pathway 는 down regulation 되었다. 결론: 유전자의 변화는 DEHP 라는 환경 호르몬이 여성의 다낭성난소증후군이나 자궁내막증 등의 발병요인으로 작용할 가능성이 있음을 보여준다. 특히 다낭성난소증후군과 연관성이 있는 gluconeogenesis 관련 유전자들의 변화는 DEHP 가 다낭성난소증후군의 주된 발병요인이 될 가능성이 있음을 시사한다. DEHP 에 노출된 세포들은 세포주기가 변화하고 apotosis 가 감소하는 경향을 보이는데, 이는 자궁내막증 식증이나 자궁내막증 등 자궁내막의 과다증식성향을 보이는 질환들에서 나타나는 세포 변화와 관련이 있다.

밀링용 칩 브레이커 인서트의 절삭력 예측

김국원,이우영,신효철 대한기계학회 1993 대한기계학회논문집 Vol.17 No.11

In this paper, the effects of chip breaker configuration on cutting forces for various cutting conditions are investigated and a method for predicting cutting forces effectively for chip breaker insert in milling is described. Based on the shear plane model and the relevant equations already existing for the relation among the parameters, the method makes use of the analytic geometric approach considering the configuration of cutting too by a 3-dimensional coordinate transformation matrix. The groove type chip breaker insert is modeled to be a double rake insert, represented by the first radial rake angle, the second radial rake angle and the length of land, and the program analyzing the cutting forces is developed. The program capability is verified by comparing the results with the experimental ones for a single cutter; and in case of primary cutting forces, the results of simulation and experiments agree very well showing 2%~16.7% difference within the feed rate range investigated.

2차원 저속절삭에 대한 유한요소 해석

김국원,안태길,이우영 한국기계가공학회 2006 한국기계가공학회지 Vol.5 No.2

An introduction to orthogonal cutting model by FEM is given, followed by a review of similar work. The cutting process is treated as quasi-static and strain rate insensitive, so the model is applicable only to low speed cutting operation. Chip separation is accomplished along a predefined cutting path by means of an element death procedure. Contact elements with friction capability are used to model the interaction between the tool and the workpiece. FEM results are compared with cutting experiments with low speed for brass, and good correlations are found.

치수공차가 고려된 광디스크 드라이브의 방진마운트 설계에 관한 연구

김국원,김남웅 한국소음진동공학회 2002 한국소음진동공학회 논문집 Vol.12 No.9

With the increase of storage density, high rotational speed and high access technologies in optical disk drive, mechanical issues, mainly noise and vibration, become critical. Up to now the researches of rubber mount for anti-vibration focused on how to calculate the static and the dynamic stiffness of rubber mount and loaned out consideration of the dimensional tolerance of rubber mount for anti-vibration. This paper presents the effects of dimensional tolerance of rubber mount for anti-nitration on the dynamic characteristics of optical disk drive by finite element analysis and dynamic test. The relation between dimensional tolerance and dynamic characteristics of optical disk drive is observed and discussed.

열 나노임프린트 공정에서 가압조건이패턴전사에 미치는 영향

김국원,이우영,이기연 한국반도체디스플레이기술학회 2013 반도체디스플레이기술학회지 Vol.12 No.4

Nanoimprint lithography (NIL) is the next generation photolithography process in which the photoresist is dispensed onto the substrate in its liquid form and then imprinted and cured into a desired pattern instead of using traditional optical system. There have been considerable attentions on NIL due to its potential abilities that enable cost-effective and high-throughput nanofabrication to the display device and semiconductor industry. In this paper, a pressure vessel type imprinting system was used to imprint patterns with two type pressure values (25 bar, 30 bar) and two type pressure keeping times (5 min, 10 min). The height of transferred pattern and the thickness of residual layer were measured and effects of pressurization conditions - pressure and pressure keeping time - on the pattern transfer in thermal NIL were investigated.