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        검색결과 563

        102.
        2017.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of the work was to investigate the thermo-electrical properties of low cost and rapidly produced randomly oriented carbon/carbon (C/C) composite. The composite body was fabricated by combining the high-pressure hot-pressing (HP) method with the lowpressure impregnation thermosetting carbonization (ITC) method. After the ITC method step selected samples were graphitized at 3000°C. Detailed characterization of the samples’ physical properties and thermal properties, including thermal diffusivity, thermal conductivity, specific heat and coefficient of thermal expansion, was carried out. Additionally, direct current (DC) electrical conductivity in both the in-plane and through-plane directions was evaluated. The results indicated that after graphitization the specimens had excellent carbon purity (99.9 %) as compared to that after carbonization (98.1). The results further showed an increasing trend in thermal conductivity with temperature for the carbonized samples and a decreasing trend in thermal conductivity with temperature for graphitized samples. The influence of the thickness of the test specimen on the thermal conductivity was found to be negligible. Further, all of the specimens after graphitization displayed an enormous increase in electrical conductivity (from 190 to 565 and 595 to 1180 S/cm in the through-plane and in-plane directions, respectively).
        4,200원
        105.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have identified 22 quasars in the AKARI far-infrared all-sky Bright Source Catalogue, using a matching radius of < 10", and excluding matches which are close to foreground extended sources or cirrus. We have confirmed a relation between quasar optical luminosity and far-infrared luminosity which was found in an earlier study. In addition, we have found that the 11 sources which are at redshift z > 1 are magnified with respect to the predicted far-infrared luminosity, and consider this may be due to gravitational lensing. If confirmed, this would provide a new way to identify lenses; if not, we may have identi ed an interesting new population of extreme starbursting quasars.
        3,000원
        106.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We built a 8 μm selected sample of galaxies in the NEP-AKARI eld by defining 4 redshift bins with the four AKARI bands at 11, 15, 18 and 24 microns (0:15 < z < 0:49, 0:75 < z < 1:34, 1:34 < z < 1:7 and 1:7 < z < 2:05) . Our sample contains 4079 sources, 599 are securely detected with Herschel/PACS. Also adding ultraviolet (UV) data from GALEX, we fit the spectral energy distributions using the physically motivated code CIGALE to extract the star formation rate, stellar mass, dust attenuation and the AGN contribution to the total infrared luminosity (LIR). We discuss the impact of the adopted attenuation curve and that of the wavelength coverage to estimate these physical parameters. We focus on galaxies with a luminosity close the characteristic L* IR in the different redshift bins to study the evolution with redshift of the dust attenuation in these galaxies.
        4,000원
        107.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The recent updates of the North Ecliptic Pole deep (0.5 deg2, NEP-Deep) multi-wavelength survey covering from X-ray to radio-wave is presented. The NEP-Deep provides us with several thousands of 15 μm or 18 μm selected galaxies, which is the largest sample ever made at these wavelengths. A continuous filter coverage in the mid-infrared wavelength (7, 9, 11, 15, 18, and 24 μm) is unique and vital to diagnose the contributions from starbursts and AGNs in the galaxies out to z=2. The new goal of the project is to resolve the nature of the cosmic star formation history at the violent epoch (e.g. z=1{2), and to find a clue to understand its decline from z=1 to present universe by utilizing the unique power of the multiwavelength survey. The progress in this context is brie y mentioned.
        4,000원
        108.
        2016.12 구독 인증기관 무료, 개인회원 유료
        The natural gas market has been expanding in size and has attracted particular attention across the global energy market. Although most natural gas transportation is carried out through pipelines, almost one third of it is done with the help of merchant vessels, capable of carrying liquefied natural gas. These LNG carriers have a special design and thus can be treated as a separate class of global fleet. New vessels are huge capital investments by vessel owning companies and just like other vessel classes; the new shipbuilding prices for the LNG segment continue to be a key aspect in the decision making of business players. Additionally these prices can be volatile as new ship building prices fluctuate with time. This paper attempts to analyse the volatility of new ship building prices of LNG carriers. For the study, the average ship building prices for all the LNG carriers having volume carrying capacity is between 160,000 – 173,000 cbm to be delivered between 2016 – 2019 were taken into account. For the analysis, GARCH and EGARCH methods were applied on the data set. The analysis concluded that there is a great deal of volatility in the new ship building prices of LNG vessels. It was also identified that negative shocks were more persistent the positive shocks.
        4,500원
        114.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is imperious to know the reproductive parameters of the subsisting swine breed for profitable farming in Bangladesh. This study was designed to compare the reproductive parameters of sows at hilly areas between the local and crossbred at farm and backyard level. A total of 116 breedable sows were included. The data on age at puberty, litter size, birth weight, weaning weight, gestation length, interval between farrowing and number of piglets born per sow in local and crossbred sows were determined and direct questionnaire method was used for data collection. The present study revealed that age at puberty between farm and backyard system of crossbred sows was 8.88±0.153 and 9.85±0.221 months, respectively. The farrowing interval was shorter in crossbred sows which were kept in farming system rather than backyard system. The interval between farrowing and onset of estrus was shorter in crossbred sows. The gestation length was almost similar between backyard and farm condition. The number of litter size per sow per farrowing was 8.45±0.41 in crossbred and 7.17±0.250 in local pigs at backyard system. The birth weight and weaning weight were more in farm conditions than backyard system. The age at puberty in local breed was lower than the crossbred and litter size was 8.45±0.407 in crossbred which was higher than local breed 7.17±0.250 in backyard system. These results suggest that reproductive parameters of local sow need to be improved for better production and crossbred sows should be reared for obtaining desired productivity.
        4,000원