1,723,942 research outputs found
페라이트-마르텐사이트-베이나이트 강의 인장 변형거동의 평가
No full text학위논문(석사) - 한국과학기술원 : 핵공학과, 1989.2, [ iii, 47 p. ]The deformation behavior of tri-phase (ferrite-bainite-martensite) steels was evaluated theoretically. There have been many works about dualphase steels, but there is no theory applicable to evaluating the flow curves of tri-phase steels yet. To induce the equations giving flow curves of tri-phase steels, this study used some theories which are applicable to dual-phase steels or two phase materials. In order to predict the actual stress-strain state of each phase, the stress concentration and the plastic relaxation were considered. In the stress concentration, the self consistent continuum model which was on the basis of Eshelby``s analysis was used and to consider the plastic relaxation the prismatic punching proposed by Ashby was predicted quantitatively. From the stress-strain state of each phase, the flow curves of tri-phase steels were induced by the law of mixture. From the results of the above calculation, theoretical flow curve of each specimen was compared with the experimental one, respectively. In every cases, theoretical curves show approximately agreement with the experimental ones. Also the effects of the introduction of bainite on the mechanical properties of dualphase steels were considered partly. It was shown that the introduction of bainite increases the ductility of dual phase steels and changes the properties of each phase.한국과학기술원 : 핵공학과
KIOST_CTD
No full textKIOST_CTD is a dataset of temperature and salinity observations collected by KIOST using CTD from 1983 to 1991 around the Korean Peninsula. This dataset consists of temperature and salinity profiles from 916 stations, with provided as observation depths.
- Area: around Korea marginal seas
- Station: 916
- Variable: Year, Month, Day, Longitude, Latitude, depth, temperature, salinit
Temporal variation of HCO+ 1–0 galactic absorption lines toward NRAO 150 and BL Lac
No full textWe present observations of HCO+ 1-0 absorption lines toward two extragalactic compact radio sources, NRAO 150 and BL Lac with the Korean VLBI Network in order to investigate their time variation over 20 years by Galactic foreground clouds. It is found that the line shape of -17 km s(-1) component changed marginally during 1993-1998 period and has remained unaltered thereafter for NRAO 150. Its behavior is different from that of H2CO 1(10)-1(11), suggesting chemical differentiation on similar to 20 AU scale, the smallest ever seen. On the other hand, BL Lac exhibits little temporal variation for the HCO+ and H2CO lines. Our observation also suggests that Korea VLBI Network performs reliably in the spectrum mode in that the shapes of the new HCO+ 1-0 spectra are in good agreement with the previous ones to an accuracy of a few percent except the time varying component toward NRAO 150.OAIID:RECH_ACHV_DSTSH_NO:T201727760RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A072407CITE_RATE:1.545DEPT_NM:물리·천문학부EMAIL:[email protected]_YN:YN
Simultaneous survey of water and class I Methanol masers toward red MSX sources
No full textWe report simultaneous single-dish surveys of 22 GHz H2O and 44 and 95 GHz class I CH3OH. masers toward 299 Red Midcourse Space Experiment Sources in the protostellar stage. The detection rates are 45% at 22 GHz, 28% at 44 GHz, and 23% at 95 GHz. There are 15, 53, and 51 new discoveries at 22, 44, and 95 GHz, respectively. We detect high-velocity (>30 km s(-1)) features in 27 H2O maser sources. The 95 GHz maser emission is detected only in 44 GHz maser sources. The two transitions show strong correlations in the peak velocity, peak flux density, and isotropic maser luminosity, indicating that they are likely generated in the same sites by the same mechanisms. The 44 GHz masers have much narrower distributions than 22 GHz masers in the relative peak velocity and velocity range, while 6.7 GHz class. II CH3OH masers have distributions intermediate between the two. The maser luminosity significantly correlates with the parental clump mass, while it correlates well with the bolometric luminosity of the central protostar only when data of the low-mass regime from the literature are added. Comparison with the results of previous maser surveys toward massive star-forming regions suggests that the detection rates of 22 and 44 GHz masers tend to increase as the central objects evolve. This is contrary to the trends found in low-and intermediate-mass star-forming regions. Thus, the occurrence of both masers might depend on the surrounding environments as well as on the evolution of the central object.OAIID:RECH_ACHV_DSTSH_NO:T201826032RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A072407CITE_RATE:5.551DEPT_NM:물리·천문학부EMAIL:[email protected]_YN:YY
Speckle Noise Reduction and Edge Enhancement in Ultrasound Images Based on Wavelet Transform
No full textFor B-mode ultrasound images, we propose an image enhancement algorithm based on a multi-resolution approach, which consists of edge enhancing and noise reducing procedures. Edge enhancement processing is applied sequentially to coarse-to-fine resolution images obtained from wavelet-transformed data. In each resolution, the structural features of each pixel are examined through eigen analysis. Then, if a pixel belongs to an edge region, we perform two-step filtering: that is, directional smoothing is conducted along the tangential direction of the edge to improve continuity and directional sharpening is conducted along the normal direction to enhance the contrast. In addition, speckle noise is alleviated by proper attenuation of the wavelet coefficients of the homogeneous regions at each band. This region-based speckle-reduction scheme is differentiated from other methods that are based on the magnitude statistics of the wavelet coefficients. The proposed algorithm enhances edges regardless of changes in the resolution of an image, and the algorithm efficiently reduces speckle noise without affecting the sharpness of the edge. Hence, compared with existing algorithms, the proposed algorithm considerably improves the subjective image quality without providing any noticeable artifacts
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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