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어블레이션 영역 레이저 초음파의 시뮬레이션과 내부결함 검사
김진겸(Jin-Gyum Kim),최성호(Sungho Choi),장경영(Kyung-Young Jhang) 한국비파괴검사학회 2014 한국비파괴검사학회지 Vol.34 No.3
본 연구에서는 고출력 레이저를 재료 표면에 조사하였을 때 나타나는 어블레이션 현상에 의한 레이저 초음파의 특성을 시뮬레이션과 실험을 통해 분석하였다. 레이저 초음파 기법은 비파괴검사 분야에서 기존의 접촉식 초음파 기법을 적용하기 어려운 환경요인(고온 등)을 극복할 수 있는 장점들을 가지고 있다. 특히, 어블레이션 영역에서는 종파의 신호 세기 및 직진성이 강하므로, 투과 및 반사 신호를 통한 내부결함 검사법으로 활용하기 적합하다. 본 논문에서는 유한요소해석을 통해 어블레이션 영역에서의 레이저 초음파의 발생 및 전파를 해석하였다. 그리고 개발된 유한요소해석 모델을 활용해 결함모사시편을 대상으로 B-Scan을 수행한 결과, 실험 결과와 동일하게 나타나는 것을 확인하였고, 이로부터 개발된 해석모델의 타당성을 검증할 수 있었다. In the present study, the characteristics of laser ultrasound in the ablation regime are investigated using simulations and experiments. The laser ultrasonic technique has been recognized as a noncontact method in the field of nondestructive tests (NDTs). In hostile environments (such as hot temperatures), this method has various advantages over the conventional contact ultrasonic method. In particular, in the ablation regime, the laser ultrasonic technique is suitable for inspecting internal defects because of the high amplitude and directivity of the longitudinal wave. In this paper, a simulation model for laser ultrasound in the ablation regime was developed. This model was subsequently applied to a defective specimen using the B-scan method to locate defects. Finally, we performed an experimental test to verify the simulation results. Consequently, the simulation demonstrated good agreement with the experimental test.
고출력 CW 레이저에 의한 CMOS 영상 센서의 손상 분석
김진겸(Jin-Gyum Kim),최성호(Sungho Choi),윤성희(Sunghee Yoon),장경영(Kyung-Young Jhang),신완순(Wan-Soon Shin) 대한기계학회 2015 大韓機械學會論文集A Vol.39 No.1
고출력 레이저에 의한 영상 센서의 손상 분석 연구를 수행하였다. 고출력 레이저에 의한 금속의 손상에 관한 연구는 많이 이루어져 있지만, 상대적으로 고출력 레이저에 취약한 영상 시스템의 손상 연구는 미비한 상태이다. 본 논문에서는 CMOS 영상 센서에 고출력 레이저가 조사 되었을 때, 영상 센서가 받는 손상에 대해 실험적으로 분석하였다. 고출력 레이저 소스로는 근적외선대역의 연속발진 광섬유 레이저를 사용하였으며, 레이저 세기와 조사시간에 따른 CMOS 영상 센서의 영구적 손상 및 영상 품질을 분석하였다. 그 결과 조사시간과 레이저세기가 증가함에 따라 먼저 색상 손상이 나타나고 이후 작동 불능 상태가 되었으며, 이러한 손상은 조사시간보다 레이저 세기에 더 큰 영향을 받는 것으로 나타났다. This paper presents the results of an experimental analysis of the high-power laser (HPL)-induced damage to a complementary metal-oxide semiconductor (CMOS) image sensor. Although the laser-induced damages to metallic materials have been sufficiently investigated, the damages to electric-optic imaging systems, which are very sensitive to HPLs, have not been studied in detail. In this study, we experimentally analyzed the HPL-induced damages to a CMOS image sensor. A near-infrared continuous-wave (CW) fiber laser was used as the laser source. The influences of the irradiance and irradiation time on the permanent damages to a CMOS image sensor, such as the color error and breakdown, were investigated. The experimental results showed that the color error occurred first, and then the breakdown occurred with an increase in the irradiance and irradiation time. In particular, these damages were more affected by the irradiance than the irradiation time.
양치교실 운영여부에 따른 학부모의 자녀에 대한 칫솔질 지도 상태
류혜겸 ( Hae-gyum Ryu ),성미경 ( Mi-gyung Seong ),나미향 ( Mi-hyang Na ),권선화 ( Sun-hwa Kwon ),김성애 ( Sung-ae Kim ),진미영 ( Mi-young Jin ),황세현 ( Se-hyun Hwang ),성혜진 ( Hye-jin Seong ) 한국치위생학회(구 한국치위생교육학회) 2016 한국치위생학회지 Vol.16 No.4
Objectives: The purpose of the study is to investigate the parents`` toothbrushing guidance on the children by operation of toothbrushing room. Methods: A self-reported questionnaire was completed by 790 parents of first, fourth, and sixth grade students of J elementary school in Changwon from June 1 to 30, 2013. J elementary school did not have toothbrushing room. The questionnaire consisted of general characteristics of the subjects (3 items), toothbrushing room operation (3 items), and toothbrushing (7 items). Data were analyzed using SPSS 20.0 program. Results: Parents of high school diploma demanded the establishment of toothbrushing room (p<0.05) and parents having undergraduate course tended to want the operation of toothbrushing room (p<0.05) and children``s dental health care (p<0.05). Parents within forties tended to have higher concern for their children``s toothbrushing (p<0.05) and toothbrushing room operation (p<0.05). They tried to have much interest in their dental health checkup and toothbrushing frequency. Conclusions: The establishment and operation of toothbrushing room is very important to elementary school children. The toothbrushing guidance by parents will enhance children``s dental health knowledge and maintain lifelong dental healthcare for the children.
Cloning and Regulation of Schizosaccharomyces pombe Gene Encoding Ribosomal Protein L11
Kim, Hong-Gyum,Lee, Jin-Joo,Park, Eun-Hee,Sa, Jae-Hoon,Ahn, Ki-Sup,Lim, Chang-Jin Korean Society for Biochemistry and Molecular Biol 2001 Journal of biochemistry and molecular biology Vol.34 No.4
The cDNA encoding ribosomal protein was identified from a cDNA library of Schizosaccharomyces pombe. The nucleotide sequence of the 548 by cDNA clone reveals an open reading frame, which encodes a putative protein of 166 amino acids with a molecular mass of 18.3 kDa. The amino acid sequence of the S. pombe L11 protein is highly homologous with those of rat and fruit, while it is clearly less similar to those of prokaryotic counterparts. The 1,044 by upstream sequence, and the region encoding N-terminal 7 amino acids of the genomic DNA were fused into the promoterless $\beta$-galactosidase gene of the shuttle vector YEp357 in order to generate the fusion plasmid pHY L11. Synthesis of $\beta$-galactosidase from the fusion plasmid varied according to the growth curve. It decreased significantly in the growth-arrested yeast cells that were treated with aluminum chloride and mercuric chloride. However, it was enhanced by treatments with cadmium chloride ($2.5\;{\mu}M$), zinc chloride ($2.5\;{\mu}M$), and hydrogen peroxide (0.5 mM). This indicates that the expression of the L,11 gene could be induced by oxidative stress.
서호건,Jin-Gyum Kim,윤성희,장경영 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.16 No.13
The laser ultrasonic technique in the ablation regime was studied for the effective excitation of ultrasound. First, the optimal laser beam intensity to maximize the amplitude of ultrasound was obtained. This is useful because the amplitude of ultrasound does not always increase as the laser beam intensity increases due to the plasma shielding effect. When the laser energy is fixed, for a steel specimen, the maximum ultrasonic amplitude is obtained at the laser beam intensity in the range of 10-20 GW/cm2. In addition, an inline method to obtain the optimal laser beam intensity was proposed based on the phenomena that the amplitude of the air-borne sound induced by plasma is inversely proportional to the amplitude of the generated ultrasound. Experimental results verified the usefulness of the proposed method by showing that the amplitude of ultrasound reached its maximum when the plasma-induced airborne sound disappeared.
( Da-gyum Lee ),( Sungweon Ryoo ),( Yoohyun Hwang ),( Eun-jin Park ),( Jung-hyun Kim ) 대한결핵 및 호흡기학회 2021 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.129 No.-
Background Mycobacterium abscessus (M. abscessus) causes chronic pulmonary infections and is the most difficult Nontuberculous Mycobacteria (NTM) to treat due to its resistance to current antimicrobial drugs, with a treatment success rate of 45.6 %. Thus, novel treatment drugs are needed, of which we identified the drug Clomiphene Citrate (CC), which treats infertility in women, to exhibit inhibitory activity against M. abscessus. Methods To assess the potential of CC as a treatment for M. abscessus pulmonary diseases, we measured its efficacy in vitro and established the intracellular activity of CC against M. abscessus in human macrophages. Results CC significantly inhibited the growth of not only wild-type M. abscessus strains, but also clinical isolate strains and clarithromycin (CLR)-resistant strains of M. abscessus. CC’s drug-efficacy did not have a significant cytotoxicity in the infected macrophages. Furthermore, CC worked in anaerobic non-replicating conditions as well as in the presence of biofilm. Conclusions The Results of this in vitro study on M. abscessus activity suggest that CC is a potential new drug for the treatment of M. abscessus infections.