http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
임지우 ( Ji Woo Im ),김범준 ( Bum Joon Kim ),김문기 ( Moon K Kim ),임병수 ( Byeong Soo Lim ) 대한금속재료학회 ( 구 대한금속학회 ) 2010 대한금속·재료학회지 Vol.48 No.11
The small punch creep (SPC) test has recently received much attention as a new alternative to the conventional uniaxial creep test because it needs only a miniature-sized specimen directly detached from an operating system or component without any serious sampling damages. However, it is difficult to obtain the equivalent uniaxial creep data directly from the SPC data. As a specimen is deformed by a punch in the SPC test, the test result is sensitive to the friction between them. Finite element analyses with various friction coefficients was performed and showed a tendency of increased SPC life with an increased friction coefficient. The necking position predicted by the SPC simulation with a proper friction coefficient showed good agreement with that observed from the real SPC test. Finally, a noble method to convert the SPC load and displacement rate into the equivalent uniaxial creep stress and strain rate, respectively, was established in this study.
임지우,이승재,장원준,권혁동,서화정,Im, Ji-woo,Lee, Seung-jay,Jang, Won-jun,Kwon, Hyeok-dong,Seo, Hwa-jeong 한국정보통신학회 2019 한국정보통신학회논문지 Vol.23 No.11
스마트폰에는 현재 다양한 보안 방식이 사용되고 있다. 그중에서도 핀 번호와 패턴 잠금 방식은 초기 스마트폰부터 사용되었을 정도로 오래 사용되었다. 하지만 패턴 잠금 방식은 오래 사용된 만큼 보안이 취약하다. 핀 번호 방식의 보안 강도가 약간 높은 정도라면 패턴 잠금 방식은 중간 정도에 그친다. 그럼에도 많은 스마트폰 사용자들은 패턴 잠금 방식을 이용하고 있는데 아직 생체보안을 지원하지 않는 기종을 사용하는 사용자가 있기 때문이다. 생체보안을 지원하지 않는 기종에서 제일 편리한 보안 방식은 패턴 잠금 방식이다. 그러나 기존의 패턴 잠금 방식은 Shoulder surfing attack과 Smudge attack에 취약하다. 따라서 패턴 잠금 방식의 편리성을 유지하면서 동시에 기존 방식의 취약점을 해결하는 방식을 제안하고자 한다. 제안하는 방식은 화면에 배치되는 각각의 점을 원형으로 배치한 뒤 무작위로 숫자를 부여하는 잠금 방식이다. 본 방식을 도입하게 된다면 기존의 취약점을 상당히 해결할 수 있다. 즉, 기존의 패턴 잠금 방식에 비해 보안성을 높일 수 있다. Currently, there are various security methods in smart phone. Among them, pin number and pattern lock were used long as they were used from early smart phone. However, security is weak that much. The security of pin number is slightly high, but the security of conventional pattern lock remains moderate. However, the conventional pattern lock is still used by several people because of convenience. This is because some users' smart phones don't support biometric security. The most convenient security method for devices that don't support biometric security is pattern lock. However, this method is vulnerable to shoulder surfing attack and smudge attack. Therefore, we introduce random pattern lock that solves the vulnerability of the conventional pattern lock while maintaining the convenience of the pattern lock. This is a lock method that places each point placed on the screen in a circular shape and assigns a random number to it. Therefore, If this is introduced, It's expected to solve vulnerability.
High Temperature Fatigue and Creep Behavior of 316L Stainless Steel
임지우,김문진,임병수 기계기술연구소 2000 성균관대학교 논문집 기계기술편 Vol.2 No.1
The heat resistant material may experience static loading, cyclic loading or both during operation. An experimental study of crack growth behavior of STS 216L austenitic stainless steel under fatigue and creep-fatigue loading conditions was carried out on compact tension specimens at various tensile hold times using trapezoidal waveform. In the crack growth experiments under hold time loading conditions, tensile hold times were ranged from 5 seconds to 100 seconds and its behavior was characterized using the ΔK parameter. The fatigue crack growth rates generally increase with hold times. In this material,, however, the crack growth rates decrease when the hold times are relatively short. This is attributed to a dccline in the cyclic crack growth rate as a result of blunting at the crack tip by creep deformation.
STS 316의 크리프 파단 거동에 미치는 장시간 시효의 영향
임지우,임병수 成均館大學校 科學技術硏究所 1999 論文集 Vol.50 No.1
Although type 316 stainless steel is widely used in reactors of petrochemical plants and pipes of steam power plants, the effect of precipitates which form during the long term exposure at service temperature, on creep properties is not known sufficiently. In this study, to investigate the influence of prior aging on the microstructure and creep properties, the 316 stainless steel was first solutionized at 1130℃ for 20 minutes and then the aged specimens for different time of 0hr, 100hrs, 1000hrs and 2200hrs were prepared at 750℃. After heat treatments, the tensile tests both at room temperature and 650℃, the constant load creep rupture tests were carried out. From the experimental results, following conclusions were obtained. (1) The rupture life of 100 hour aged specimens was found to be the shortest. It is resulted from the highest minimum creep rate. And the 0hr aged specimens showed the longest rupture life, followed by 1000hr aged and 2200hr aged specimens. (2) The value of the creep stress exponent, n, decreased as the aging time increased. The n values for the 0hr, 100hr, 1000hr, 2200hr aged specimens were to be measured 13.5, 5.7, 4.4 and 2.9. (3) The creep activation energy varied with the aging time. The activation energies for 0hr, 100hr, 1000hr and 2200hr aged specimens were calculated to be 679.1, 421.6, 527.5 and 517.2 kJ/mol.
열처리를 통한 SNCM220강 권축의 피로특성 향상에 관한 연구
이호성,임지우,임병수 成均館大學校 科學技術硏究所 1997 論文集 Vol.48 No.2
To find out the reason of fracture, specimens were made from the fractured winding shaft and the mechanical properties as well as their microstructures were investigated. Several heat treatments, including caburizing and tempering, were carried out to improve the microstructure, mechanical properties, fatigue crack propagation and rotating bending fatigue characteristics. Through these experiments, following conclusions were obtained, (1) Carburized and tempered specimens showed greatly improved mechanical properties including impact energy, hardness and strength. (2) Crack propagation of the carburized and tempered specimens were faster than that of the original fractured specimens under the same ΔK. However, it was found that, in the early stage, the fatigue crack initiation and growth for the carburized and tempered specimen was more difficult. (3) The fatigue strength of the carburized and tempered specimens increased more than twice than that of the original fractured winding shaft.