• 제목/요약/키워드: phase-contrast

검색결과 833건 처리시간 0.025초

현대패션에 표현된 dynamism의 조형성 연구 (A Study on the Formation of Dynamism in the Modern Fashion)

  • 이은숙
    • 한국의상디자인학회지
    • /
    • 제4권1호
    • /
    • pp.143-153
    • /
    • 2002
  • Fashion has been analyzed and explained in diverse ways. Fashion, like every phase of culture, is a reflection of the Zeitgeist. In order to understand the changing fashion we must understand the changing society. For fashion of a period are expressions of the interrelation of the various elements of the culture, including the social and political values, the economic and industrial progress, art, the development of technology, etc... Particularly fashion is closely connected with a style of art. In a style of art, futurism focused on the "dynamism" resulting from super-speed and high-technology. This study aimed to review literatures, fashion magazines, web-site in order to know how the dynamism of futurism is expressed in modern fashion. The results of this study were as follows; 1. Dynamism was expressed by means of lines, colors, patterns through the eyesights visually. Asymmetrical oblique lines, zig-zag lines or bold cutting expressed the mechanical and offensive dynamism. In contrast, such lines as curves and spirals expressed the soft and natural dynamism. Primary colors or complementary contrast expressed energetic and rhythmical dynamism. The geometrical patterns and automobile wheels patterns expressed dynamism resulting from mechanical aesthetics. 2. Dynamism was expressed through repeat of lines, colors, patterns, and textiles. Particularly Vinyl material, fluorescent material, metallic material, beads, and spangle expressed a strong dynamism. On the other hand, natural materials, paper and other similar ones are used to signify the orientation towards a futuristic high-technology society.y society.

  • PDF

레이저 플라즈마 기반의 생물의료용 연 X-선 현미경 설계 (Conceptual Design of Laser Plasma-based Soft X-ray Microscope system for Biomedical Application)

  • 김경우;윤권하
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 2003년도 춘계학술대회 논문집
    • /
    • pp.690-693
    • /
    • 2003
  • Soft x-ray microscopy provides a unique set of capabilities in-between those of visible light and electron microscopy. It has long been recognized that nature provides a 'water window' spectral region between the K shell x-ray absorption edges of carbon (~290eV) and oxygen (~540eV), where organic materials show strong absorption and phase contrast, while water is relatively non-absorbing. This enables imaging of hydrated biological specimens that are several microns thick with high intrinsic contrast using x-rays with a wavelength of 2.3~4.4nm. Soft X-ray microscopy is therefore well suited to the study of specimens like single biological cells. The most direct advantage of X-ray microscope is their high spatial resolution when compared with visible light microscopes, combined with an ability to image hydrated specimens that are several microns with a minimum of preparation. Our study describes the conceptual design of soft x-ray microscope system based on a laser-based source for biomedical application with high resolution ($\leq$50nm) and short exposure time ($\leq$30sec).

  • PDF

등방 및 이방성 암반내 공동의 열역학적 거동에 관한 전산모델연구 (A Study on the Thermo-mechanical Behavior of Underground Openings in lsotropic and Structurally Snisotropic Rock Masses)

  • 문현구;주광수
    • 터널과지하공간
    • /
    • 제1권2호
    • /
    • pp.181-203
    • /
    • 1991
  • The effects of geologic structures such as rock joins and bedding planes on the thermal conductivity of a discontinuous rock mass are studied. The expressions for the equivalent thermal conductivities of jointed rock masses are derived and found to be anisotropic. The degree of anisotropy depends primarily on the thermal properties contrast between the joint phase and surrounding intact rock, the joint density expressed as volume fraction and the inclination angle of the joint. Within the context of 2-dimensional finite element heat transfer scheme, the isotherms around a circular hole are analyzed for both the isotropic and anisotropic rock masses in 3 different thermal boundary conditions. i.e. temperature, heat flux and convection boundary conditions. The temperature in the stratified anisotripic rock mass is greatly influenced by the thermal properties of the rock formation in contact with the heat source. Using the excavation-temperature coupled elastic plastic finite element method, analyzed is the thermo-mechanical stability of a circular opening subjected to 10$0^{\circ}C$ at a depth of 527m. It is found that the thermal stress concentration was enough to deteriorate the stability and form a plastic yield zone around the opening, in contrast to the safety factor greater than 2 resulted form the excavation-only analysis.

  • PDF

Daily Growth Increments and Lunar Pattern in Otolith of the Eel, Anguilla japonica, in the Freshwater

  • LEE Tae-Won;LEE Kwan-Soon
    • 한국수산과학회지
    • /
    • 제22권1호
    • /
    • pp.36-40
    • /
    • 1989
  • The eels, Anguilla japonica, were reared in a tank with daily feeding for up to 97 days, and otoliths were regularly collected for the observation of their microstructures. Microscopic observation of the thin-sectioned otolith under dark field provided significant information on daily growth increments as well as the difference in visual contrast shown by the increments. Clearly defined elver mark formed during the metamorphosis from leptocephalus to the elver can be considered as the origin of the age for the sedentary yellow eel in continental water. The close correspondence between the number of increments outside elver mark and chronological age in days from the beginning of feeding indicates that increment deposition on a daily basis was initiated with the start of feeding for the sedentary yellow eel. Either 7 or 14 daily growth increments were grouped together into 2 alternative units, each distinguished by prominent checks or by visual contrast. The absence of any apparent environmental variations with 7 or 14 day period in the reared tank implies that the phase of the moon could be a zeitgeber for the endogenous rhythm.

  • PDF

고대비.저손실 광기록을 위한 $Te_x(Sb_{85}Ge_{15})_{100-x}$ 박막의 결정화 특성 (The Crystallization Properties of $Te_x(Sb_{85}Ge_{15})_{100-x}$ Thin films for High Contrast Ratio and Low Loss Optical Recording)

  • 김종기;김홍석;이현용;정홍배
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1997년도 하계학술대회 논문집 C
    • /
    • pp.1274-1276
    • /
    • 1997
  • We have investigated the crystallization properties of $Te_x(Sb_{85}Ge_{15})_{100-x}$ (x=0.3, 0.5, 1.0 at.%) thin films as observing the reflectance change, XRD and SEM. The reflectance difference(${\Delta}R$) between amorphous and crystalline phases appears appoximately 20%, in all films, at 780nm(diode laser wavelength). In the case of $Te_{0.5}(Sb_{85}Ge_{15})_{99.5}$ thin film, especially, ${\Delta}R$ is about 30%. Also, amophous-to-crystalline phase change is observed at all films. Therefore, $Te_{0.5}(Sb_{85}Ge_{15})_{99.5}$ thin film can be evaluated as attractive optical recording material with low loss and high contrast ratio.

  • PDF

Cellular and Biochemical Alterations in L6 Myoblast Cells Induced by 6-Aminonicotinamide

  • Jang, Min-Young;Kim, Sun-Jung;Shin, Sook;Park, In-Kook
    • Animal cells and systems
    • /
    • 제11권1호
    • /
    • pp.17-22
    • /
    • 2007
  • The effects of antimetabolite 6-AN (6-amino-nicotinamide) on viability and morphology of L6 myoblast cells have been investigated. 6-AN ($100{\mu}M$) induced a time-dependent decrease in cell viability with respect to the untreated control cells. Following 6-AN administration the viability rate started to decline sharply, reaching about 23% of the untreated control cells at 48 h. Inverted phase-contrast microscopy revealed that 6-AN caused characteristic morphological changes such as irregularly elongated and stellate shape of cells, round-shaped nucleus, cytoplasmic vacuolization, irregular cell arrangements and formation of large spaces among cell clusters. The concentrations of ATP and $NAD^{+}$ in the 6-AN treated cells were significantly lower (p < 0.01) than those of the untreated control cells. In contrast, the concentration of AMP was significantly increased by the 6-AN treatment. Activities of catalase, superoxide dismutase and glutathione peroxidase in 6-AN treated cells were significantly higher (p < 0.01) than those of the untreated control cells. The activities of glyceraldehyde-3-phosphate dehydrogenase in 6-AN treated cells were significantly lower (p < 0.01) than those of the untreated control cells. The results suggest that 6-AN caused marked reduction of cell viability and alterations of some important metabolites and enzymes.

격자 간섭계에서 탈봇 패턴의 섬광체 스크린 투과 시 전달 특성에 대한 시뮬레이션 연구 (A Simulation Study on the Transfer Characteristics of the Talbot Pattern Through Scintillation Screens in the Grating Interferometer)

  • 김대승;김영주;이세호;이승욱
    • 대한방사선기술학회지:방사선기술과학
    • /
    • 제42권1호
    • /
    • pp.67-75
    • /
    • 2019
  • Grating interferometry based imaging technology is a kind of radiation imaging system, which can acquire not only absorption image but also phase difference and dark field image using the Talbot pattern. However, because of the technological difficulties and high cost of fabricating the gratings that make up the system, much efforts are being made to look for ways to replace them. The is a preliminary study to see how the Talbot pattern transfer through various kinds of scintillators and if the optical grating can be a way to replace the conventional absorption gratings. The geometry of the interferometer, the scintillator model, and the scintillator thickness are the main inputs for our simulation. We have used the concept of modulation for quantitative analysis of the contrast ratio of the Talbot pattern. This research is expected to provide very useful information on the design of optical gratings, which is an alternative way to analyze the Talbot pattern, which we have filed a patent on.

Current Landscape and Future Perspectives of Abbreviated MRI for Hepatocellular Carcinoma Surveillance

  • Hyo Jung, Park;Nieun Seo;So Yeon Kim
    • Korean Journal of Radiology
    • /
    • 제23권6호
    • /
    • pp.598-614
    • /
    • 2022
  • While ultrasound (US) is considered an important tool for hepatocellular carcinoma (HCC) surveillance, it has limited sensitivity for detecting early-stage HCC. Abbreviated MRI (AMRI) has recently gained popularity owing to better sensitivity in its detection of early-stage HCC than US, while also minimizing the time and cost in comparison to complete contrast-enhanced MRI, as AMRI includes only a few essential sequences tailored for detecting HCC. Currently, three AMRI protocols exist, namely gadoxetic acid-enhanced hepatobiliary-phase AMRI, dynamic contrast-enhanced AMRI, and non-enhanced AMRI. In this study, we discussed the rationale and technical details of AMRI techniques for achieving optimal surveillance performance. The strengths, weaknesses, and current issues of each AMRI protocol were also elucidated. Moreover, we scrutinized previously performed AMRI studies regarding clinical and technical factors. Reporting and recall strategies were discussed while considering the differences in AMRI protocols. A risk-stratified approach for the target population should be taken to maximize the benefits of AMRI and the cost-effectiveness should be considered. In the era of multiple HCC surveillance tools, patients need to be fully informed about their choices for better adherence to a surveillance program.

4차원 TRICKS 자기공명혈관조영술과 기존 TOF 자기공명혈관조영술의 비교 및 유용성 (The Value of Comparison with Four Dimension Time Resolved Imaging of Contrast Kinetics(TRICKS) MRA by Time of Flight(TOF) MRA)

  • 배성진;임청환;박병래;신운재;김정삼
    • 한국콘텐츠학회논문지
    • /
    • 제10권3호
    • /
    • pp.215-221
    • /
    • 2010
  • Time Resolved Imaging of Contrast Kinetics 기법을 이용한 4차원 자기공명혈관조영술 (TRICKS-MRA)영상과 기존 TOF-MRA영상을 비교하여 임상적 유용성에 대해 알아보고자 하였다. 총17명 중 뇌혈관 질환이 의심되는 11명과 뇌종양을 의심하는 6명을 대상으로 TOF-MRA와 TRICKS-MRA을 시행한 후 17 대상자 중 11명에서 DSA를 추가적으로 시행하였다. TOF-MRA는 공간해상력보다 시간해상력이 부족하였고, TRICKS-MRA에서는 TOF-MRA보다 공간분해능은 부족한 점이 많지만 영상판독에 큰 영향은 없었고 모든 대상자에서 동맥과 정맥의 구별이 가능하여 시간분해능이 우수한 것을 나타났다. 또한 종양과 혈관과의 관계성 평가에서 TOF-MRA보다 좋은 것으로 나타났다. TRICKS-MRA방법은 시간대별로 동맥, 모세혈관, 정맥기를 신속하면서 쉽게 4차원적으로 영상화가 가능하여 앞으로 임상에서 이용도가 더욱 증가 할 것으로 사료된다.

전산화단층촬영의 소요시간 분석에 기반한 방사선사의 적정인력 산정에 관한 연구 (Estimation of Appropriate Number of Radiologic Technologist Based on Analysis of Time Required for Computed Tomography)

  • 이기백;김영균;김은혜;김연민
    • 대한방사선기술학회지:방사선기술과학
    • /
    • 제45권3호
    • /
    • pp.213-223
    • /
    • 2022
  • Although the number of computed tomography(CT) is increasing every year, it is insufficient to establish appropriate workload calculation standards of radiologic technologist to provide optimal medical services to patients, such as patient safety management and infection management. The purpose of this study is to present guidelines for calculating the appropriate workload of radiologic technologist by analyzing the work flow of CT procedures and the time required for CT examination in major hospitals. As for the study subjects and methods, the appropriate process for each step of CT examination was investigated to systematically present the process and time required for the actual examination, and the CT procedure time of 104,105 adult patients and 465 pediatric patients under the age of 6 were analyzed. For the time required, data according to the use of contrast medium, procedure type, and adult/child were collected and compared. The test time of CT examination using contrast medium took about 13 minutes when one radiologic technologist worked and about 9 minutes when two radiologic technologists worked. The time required for the procedures were statistically significant depending on the presence or absence of contrast medium, multi-phase procedure, and patient age (considering pediatric patients). As a result, in order to thoroughly perform patient safety and infection management, the appropriate workload increased by about 40% when there were two radiologic technologists. The limit workload was an average of 32 people per day with one radiologic technologist per 15 minutes, and 48 people per day with two radiologic technologist per 10 minutes. This is a marginal workload, and in the case of procedures that require more time to acquire radiographic images, the interval between reservations should be widened.