http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
오민철 대한영상의학회 1996 대한영상의학회지 Vol.35 No.3
Purpose : To evaluate the patterns of pseudo-lesions present on spiral CT hepatic arteriography (CTHA).Materials and Methods : One hundred and seventy five patients (161 men and 14 women, aged 15-70 years [mean, 52years]) who underwent spiral CTHA for the detection of hepatic lesions were retrospectively reviewed.Pseudo-lesion type was determined by comparing hyperattenuating lesions on CTHA with the findings ofultrasonography, conventional or multi-phase CT, Lipiodol CT, angiography, CT arterial portography(CTAP), andfollow-up of spiral CTHA. Pseudo-lesions were classified according to site, size and shape. Results : A total of77 pseudo-lesions were found in 56 of the 175 patients(32.6%), and were classified into the following types :peritumoral(n=18), segment I(n=3), segment IV(n=3), gallbladder fossa (n=13), subsegmental (n=3), subcapsular(n=13), straight line sign (n=10), arterioportal shunt (n=13), and technical error (n=1). Fifteen of 77pseudo-lesions(19.5%) showed hyperattenuation on CTHA and isoattenuation on CTAP, in contrast to adjacent liverparenchyma. Conclusion : In patients with hepatic mass, it is very important to understand the characteristicsite, shape and size of pseudo-lesions for the correct interpretation of CT and subsequent management of thepatient.
폴링된 폴리머 광도파로의 광축을 조절하여 제작한 수동형 편광 변환기
오민철,신상영 대한전자공학회 1995 전자공학회논문지-A Vol.32 No.12
A novel passive TE/TM polarization mode converter is fabricated by using poled polymer waveguides. The optic axis of the poling induced waveguide is slowly rotated by using a slowly varying structure of poling electrodes. Thus the polarization conversion is achieved as the guided mode propagates through the waveguide. The proposed device is simulated by a full vectorial beam propagation method (VBPM) for anisotropic medium. For the rotation length of 1 mm, the TE polarization of the guided mode is successfully converted to the TM polarization with negligible loss. Based on the simulation results, we fabricated the polarization converter which is tested by using 1.3 $\mu$m laser diode. TE to TM mode conversion is observed with a polarization extinction ratio higher than 30 dB, and the excess loss is less than 1 dB. The polarization conversion is relatively insensitive to wavelength since the device contains no periodic structures. These devices are easier to fabricate than others containing periodic structures.
균질 압연 장갑강 용접부의 방탄 성능 및 기계적 물적 상관관계 연구
오민철,김용,김재성 국방기술품질원 2022 국방품질연구논집 Vol.4 No.2
Vehicles, self-propelled guns, wheeled armored vehicles, etc. are manufactured by welding using homogeneous rolled armored steel (MIL-STD-12560) and high hardness armored steel (MIL-STD-46100). In order to verify the performance of the welded part, 'H'-shaped specimens are produced and then bulletproof tests are conducted, and the testing institutes are limited to some overseas testing institutes including the United States. In addition, it is an expensive test that requires at least 55,000 $/time including production cost. In addition, as only corporations in the United States can apply for and proceed with the bulletproof test, there is a problem that, in reality, domestic research institutes and corporations cannot test. In particular, when the low-temperature impact test, which is a general industry standard, is applied to evaluate the bulletproof performance of homogeneous rolled armored steel plates, the possibility of replacing the domestic H plate bulletproof test is expected to increase. Therefore, in this study, a basic study was conducted on the correlation between low-temperature impact toughness and hardness analysis results and bulletproof performance as a way to reduce cost/time and facilitate product supply and demand by replacing the existing H-plate bulletproof test.