• 한국광학회지
• /
• 제5권4호
• /
• pp.473-480
• /
• 1994

CARS 신호의 비선형 간섭을 이용하여 여러가지 기체의 비공명 3차 감수율을 측정하였다. 알곤 기체를 기중으로 하기 위하여 기준셀에 알곤 기체를 채우고 시료셀에 측정대상 기체를 주입하여 직렬로 배열하였다. 두 기체 셀 사이에 설치된 위상편이장치의 두께를 바꾸어 가면서 두 기체 셀에서 발생한 CARS 신호의 간섭무늬를 측정하였다. 기체의 전체 비공명 감수율의 값은 여러가지 기체에서 구한 간섭무늬의 진폭으로 부터 구하였다. 각 기체에서 전자만의 기여에 의한 비공명 감수율의 크기를 구하기 위하여 기체의 먼 공명 분광선에 의한 기여를 뺐다. 측정된 결과를 다른 연구자들이 구한 결과와 비교하였다. 본 연구에서 측정된 값의 불확정도는 5% 이내이다.

• 한국광학회지
• /
• 제5권2호
• /
• pp.298-303
• /
• 1994

두꺼운 Photoresist(PR)로 원기둥 모양을 만들고 이를 용융함으로써 미세렌즈 행렬을 제작하였다. 이 방법으로 직경 $25\mu\textrm{m}$, $50\mu\textrm{m}$, $100\mu\textrm{m}$의 렌즈를 만들고 전자주사현미경과 탐침형 표면측정기를 통해 그 모양을 확인하였다. 그리고 렌즈의 광학적 성능을 측정하기 위해 위상변이 간섭법을 사용하여 평행광의 렌즈 통과 후 파면을 구하였다. 여기서 기준 구면과의 파면오차를 구하여 렌즈 초점거리나 초점광도분포 등을 얻었다. 그 결과 직경 $100\mu\textrm{m}$, 초점거리 $164\mu\textrm{m}$의 미세렌즈는 초점의 spot 직경이 $25\mu\textrm{m}$보다 작은 것으로 측정되었다.

• 한국의류학회지
• /
• 제28권11호
• /
• pp.1536-1543
• /
• 2004

Garment is made by a 2D pattern and should be fitted to a human body which has 3D characteristics. Therefore, to design a pattern more effectively, the use of 3D information of a human body and the investigation of relationship between the 3D garment and 2D pattern are necessary. In this work, ruled surface method was used to reflect the 3D information of a human body for a pattern design. The images of the brassiere line on the woman's dress form were captured by phase-shifting projection moire system and the 3D information on the design line was obtained. 2D patterns on the various parts of the brassiere were developed directly from the 3D data by the ruled surface method. In addition, design line, the area and the amount of dart were quantified. And then we verify the appropriateness of the ruled surface method to the 2D pattern development by measuring the distribution of the space between women's figure and segmented clothing item. It was found that the ruled surface method is useful to transform the 3D design line to the 2D pattern, if we followed the steps suggested in this paper.

• 열처리공학회지
• /
• 제2권2호
• /
• pp.27-32
• /
• 1989

The effect of quenchant temperature on the surface residual stress was studied for AISI 8620 steel. Specimens were carburized at $900^{\circ}C$ in all case type furnace using a gas-base atmosphere of methanol cracked and liquefied petroleum gas, and then subjected to single reheat quenchant in oil or salt bath in the temperature range of $60^{\circ}C$ to $300^{\circ}C$. After carburizing and reheat Quenching, residual stress was measured by the hole drilling method. Experimental results showed that the surface residual stress was increased as the quenchant temperature was raised. This is in contrast to the fact that the formation of phase of low transformation strain such as bainite results in lower surface compressive stress. The greater compressive stress observed in specimens Quenched at higher temperature may be attributed to the shifting of the transformation start point farther from the surface, as was reported in other carburizing steels.

• Genomics & Informatics
• /
• 제5권3호
• /
• pp.107-112
• /
• 2007

MicroRNAs (miRNAs) are known to negatively control protein-coding genes by binding to messenger RNA (mRNA) in the cytoplasm. In innate immunity, the role of miRNA gene silencing is largely unknown. In this study, we performed microarray-based experiments using lipopolysaccharide (LPS)-stimulated macrophages derived from wild-type, MyD88 knockout (KO), TRIF KO, and MyD88/TRIF double KO mice. We employed a statistical approach to determine the importance of the commonality and specificity of miRNA binding sites among groups of temporally co-regulated genes. We demonstrate that both commonality and specificity are irrelevant to define a priori groups of co-down regulated genes. In addition, analyzing the various experimental conditions, we suggest that miRNA regulation may not only be a late-phase process (after transcription) but can also occur even early (1h) after stimulation in knockout conditions. This further indicates the existence of dynamic interactions between miRNA and signaling molecules/transcription factor regulation; this is another proof for the need of shifting from a 'hard-wired' paradigm of gene regulation to a dynamical one in which the gene co-regulation is established on a case-by-case basis.

• Journal of the Optical Society of Korea
• /
• 제18권2호
• /
• pp.146-150
• /
• 2014

We propose an experimental holographic imaging scheme combining compressive sensing (CS) theory with digital holography in phase-shifting conditions. We use the Mach-Zehnder interferometer for hologram formation, and apply the compressive sensing (CS) approach to the holography acquisition process. Through projecting the hologram pattern into a digital micro-mirror device (DMD), finally we will acquire the compressive sensing measurements using a photodiode. After receiving the data of two holograms via conventional communication channel, we reconstruct the original object using certain signal recovery algorithms of CS theory and hologram reconstruction techniques, which demonstrated the feasibility of the proposed method.

• 한국광학회지
• /
• 제17권3호
• /
• pp.209-215
• /
• 2006

협대역 천이영역을 갖는 원통형 격자전송구조 (Circular Bragg Grating: CBG) 가 최근 DWDM을 위한 광통신용 대역통과 필터로 널리 사용되고 있다. 이 원통형 Bragg 격자 구조들의 광 필터특성을 분석하기 위하여 본 논문에서는 Floquet-Babinet의 원리에 의존하는 새로운 해석적인 모드 전송선로 이른 (Modal Transmission-Line Theory: MTLT)을 제시하였다. 수치해석 결과, 제안한 해석법은 CBG의 필터특성을 분석하기 위한 유용한 프로그래밍 알고리즘을 제공하고, 다층 원통형 주기 구조들의 그 전송특성을 분석하기 위하여 쉽게 발전시킬 수 있음을 보였다.

• 한국재료학회지
• /
• 제16권11호
• /
• pp.663-667
• /
• 2006

CTAB(cetyltrimethylammonium bromide)-capped CdSe nanoparticles were prepared by using a 4 : 1(v/v) distilled water-isopropyl alcohol mixture. The cadmium chloride and sodium selenosulfate were used as the cadmium and selenium source. By the analysis of XRD and XPS, the resultant particle was confirmed to be cubic CdSe phase. TEM image showed CdSe nanoparticles with empty core. The CTAB-capped sample showed an maximum absorption at 418nm, blue-shifting compared with bulk CdSe, which indicated stronger quantum confinement effect compared with uncapped sample. From FT-IR analysis, it was found that the presence of the new peaks in the $850{\sim}1250cm^{-1}$ range indicated the existence of chemical bonding between CTAB and surface of CdSe nanoparticles. Also TG analysis indicated that there were two weight-loss steps for the CTAB-capped CdSe nanoparticles. It was suggested that CTAB played a significant role in protecting CdSe nanoparticles.

• 한국멀티미디어학회논문지
• /
• 제7권5호
• /
• pp.633-639
• /
• 2004

일반적으로 모바일 컴퓨팅에 사용되는 낙관적 동시성 제어의 성능은 트랜잭션 철회율에 민감하다. 비록 완료를 요청한 시각의 타임스탬프를 뒤로 옮김으로 해서 철회 확률을 줄일 수 있지만 일부 트랜잭션은 쓰기-쓰기 충돌을 일으키는 데이터를 접근한 후에 계속적으로 필요 없는 연산을 수행한다. 본 논문에서는 쓰기 통지 접근방식을 이용하여 그러한 트랜잭션들을 실행단계에서 철회 시킬 수 있는 낙관적인 프로토콜을 제안한다. 제안하는 프로토콜은 필요없는 연산을 줄임으로서 낙관적 동시성 제어 기법의 성능을 향상시킨다. 또한, 타임스탬프를 기초로 한 프로토콜과 제안한 프로토콜과의 성능 비교를 제시한다. 성능평가에서 제안하는 방식이 타임스탬프를 이용하는 방식보다 높은 성능을 나타낸다는 것을 보인다.

• Journal of Yeungnam Medical Science
• /
• 제36권2호
• /
• pp.67-77
• /
• 2019

The paradigm of chronic liver diseases has been shifting. Although hepatitis B and C viral infections are still the main causes of liver cirrhosis and hepatocellular carcinoma (HCC), the introduction of effective antiviral drugs may control or cure them in the near future. In contrast, the burden of nonalcoholic fatty liver disease (NAFLD) has been increasing for decades, and 25 to 30% of the general population in Korea is estimated to have NAFLD. Over 10% of NAFLD patients may have nonalcoholic steatohepatitis (NASH), a severe form of NAFLD. NASH can progress to cirrhosis and HCC. NASH is currently the second leading cause to be placed on the liver transplantation list in the United States. NAFLD is associated with obesity, type 2 diabetes, dyslipidemia, and metabolic syndrome. The pathophysiology is complex and associated with lipotoxicity, inflammatory cytokines, apoptosis, and insulin resistance. The only proven effective treatment is weight reduction by diet and exercise. However, this may not be effective for advanced fibrosis or cirrhosis. Therefore, effective drugs are urgently needed for treating these conditions. Unfortunately, no drugs have been approved for the treatment of NASH. Many pharmaceutical companies are trying to develop new drugs for the treatment of NASH. Some of them are in phase 2 or 3 clinical trials. Here, pharmacologic therapies in clinical trials, as well as the basic principles of drug therapy, will be reviewed, focusing on pathophysiology.