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        검색결과 338

        181.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Henyey-Greenstein (H-G) phase function, which is characterized by a single parameter, has been generally used to approximate the realistic dust-scattering phase function in investigating scattering properties of the interstellar dust. Draine (2003) proposed a new analytic phase function with two parameters and showed that the realistic phase function is better represented by his phase function. If the H-G and Draine's phase functions are significantly different, using the H-G phase function in radiative transfer models may lead to wrong conclusions about the dust-scattering properties. Here, we investigate whether the H-G and Draine's phase functions would indeed produce significant differences in radiative transfer calculations for two simple configurations. For the uniformly distributed dust with an illuminating star at the center, no significant difference is found. However, up to ~ 20% of difference is found when the central star is surrounded by a spherical-shell dust medium and the radiation of λ < 2000 Å is considered. It would mean that the investigation of dust-scattering properties using the H-G phase function may produce errors of up to ~ 20% depending on the geometry of dust medium and the radiation wavelength. This amount of uncertainty would be, however, unavoidable since the configurations of dust density and radiation sources are only approximately available.
        4,000원
        182.
        2010.12 KCI 등재 구독 인증기관·개인회원 무료
        The effects of improved aeration in saw dust bag cultivation on the Lentinula edodes hyphal growth were measured by CO2 concentration within the bags, the hyphal growth and bag weight loss. The aeration of the bags was controlled with 10 kinds of pore sizes of the lid and with pores on one side only or both side on the lid. In the conventional bags with a cotton plug CO2 concentration was 3.83%, the hyphal growth 2.25 ㎜/day and bag weight loss 0.84g, while in the bags with a lid 20.4㎜ diameter pore the CO2 concentration was 4.00%, the hyphal growth 2.68㎜/day and bag weight loss 1.3g. The bag with a lid pored on both top and bottom side was lower in CO2 concentration by 0.50%, higher hyphal growth rate by 0.04 ㎜/day and lower weight loss by 0.26g than the bag with a lid pored bottom side only. We concluded that the most effective lid for bag cultivation of L. edodes was the one with 20.4㎜ pores on both side of the lid.
        183.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Elution effect was studied by the reactions between Electric arc furnace(EAF)dust and conc. or dil. sulfuric acid for the purpose of recoverying of the useful metals afterwards. The methods of mixing with acids and EAF dust for the elutions were depend on the ratios of acid/EAF dust. Experimental results showed that increased the ratios of sulfuric acids, decreased the elution effects are on the Zn, Fe and Mn, and conc. sulfuric acid showed higher elution effects than dil. sulfuric acids for the all metals. But in case of Pb, dil. sulfuric acid showed higher elution effects than conc. sulfuric acids conversely. Furthermore, the reason of the extreamly low quantities of eluted Pb is caused by the low solubilities by sulfuric acids compared to the other metals, as the results of the insoluble Pb is removed by the process of filtering.
        4,000원
        189.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        EAF dust which is contained around 30% of zinc, 15% of iron and 3% of lead individually, is chemically treated by ammonium chloride, ammonia water, ammonia gas and carbon dioxide, and also tested and identified the ratios of the recovery of In by applied the variations of particle size, pH and heating temperature as well, in order to getting optimized recovery of the In metal after performing all of those processes. Experimental results showed that the rate of Zn recovery is 97% when the mixture of 1.3 of NH4Cl/EAF is heated to the temperature of 400℃ and leached by water, and 95% recovery of In when ammonia gas and carbon dioxide is added simultaneously and adjust the 9.5 of pH to the same mixture above. For the purpose of remove the impurities in the mixed sample, which is prepared by the two samples, indicated above showing as the ratio of 95% and 97% recovery, in case of applied the cementation process to it, and also by electrolytic process, produced the In plate of 95~97%, and acquired 99-99.5% of In metal ingot finally by applied the heating process at 470~500℃.
        4,000원
        192.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We present a Monte-Carlo simulation code, which solves the problem of dust-scattering in interstellar dust clouds with arbitrary light source distribution and dust density structure, and calculate the surface brightness distribution. The method is very flexible and can be applied to radiative transfer problems occurring not only in a single dust cloud, but also in extragalactic dust environment. We compare, for performance test, the result of Monte-Carlo simulation with the well-known analytic approximation for a spherically symmetric homogeneous cloud. We find that the Code approximation gives a very accurate result.
        4,000원
        193.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A plane-parallel model of the diffuse Galactic light (DGL) is calculated assuming exponential disks of interstellar dust and OB stars, by solving exactly the radiative transfer equation using an iterative method. We perform a radiative transfer calculation for a model with generally accepted scale heights of stellar and dust distribution and compare the results with those of van de Hulst & de Jong for a constant slab model. We also find that the intensity extrapolated to zero dust optical depth has a negative value, against to the usual expectation.
        4,000원
        196.
        2009.10 구독 인증기관·개인회원 무료
        197.
        2009.10 구독 인증기관·개인회원 무료
        198.
        2009.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 부산지역의 먼지 농도와 황사발원지의 기후학적 요소를 주기분석 함으로써 부산지역의 먼지농도 주기에 영향을 주는 기후학적 조건, 특히 황사 발생과의 관련성에 대하여 고찰하였다. 부산지역에서 관측된 먼지 농도 시계열 자료를 이용한 단일스펙트럼분석을 수행한 결과 배출량이나 강수 효과 등에 의해 나타난 일반적인 주기(1년, 7일) 이외에, 상대적으로 3-4년 주기가 우세하게 나타났으며, 먼지 농도와 부산지역의 기상자료 및 황사발원지에서의 풍속과의 교차스펙트럼 분석을 통한 주기 분석을 수행해 본 결과, 3-4년 주기일 때 먼지농도와 풍속, 기압은 양의 상관관계, 기온, 상대습도와는 각각 음의 상관관계가 나타났다. 이는 황사 발생 조건과 잘 부합되는 것으로 나타나, 3-4년의 먼지 농도 주기는 황사의 장거리 수송과 관련이 있는 것으로 판단된다. 또한 황사 발생은 발원지의 지표 상태에 따라 발생빈도가 달라지므로, 여러 기후학적 요소들 중 황사발원지에서의 강수량과의 주기 분석을 수행해 본 결과, 발원지에서의 강수량 그 자체보다는 발원지에서의 가뭄지수(EDI)의 시계열이 우리나라 먼지 농도의 3-4년 주기와 더 연관이 있는 것으로 나타났고 이는 기후학적으로 황사 발원지에서의 지표건조 특성의 변동성과 연관이 있는 것으로 나타났다.
        4,000원
        199.
        2009.10 구독 인증기관·개인회원 무료
        House dust mites (HDMs) play an important role in the occurrence of allergic diseases such as asthma and atopic dermatitis. Dermatophagoides pteronyssinus (Der p) is one of the most prevalent HDMs. It mediates the activation of T cells and monocytes, and induces the elevation of immunoglobulin E levels in allergic diseases. However, the effects of Der p on human monocytes have not been fully understood. In the present study, we investigated whether or not Der p has a great effect on the chemotactic activity of the human monocytic cell line, THP-1 cells, as induced by CC chemokines. We also show that the Der p extract (DpE) increased the chemotactic activity of THP-1 cells in response to MCP-1, RANTES, MIP-1α, and TARC, but has no effect on the expressions of CC chemokine receptors (CCRs) binding to CC chemokines in THP-1 cells. Protease inhibitors, such as aprotinin and E64, blocked the increased chemotaxis, while cytoplasmic Ca2+ influx mediated by these chemokines was inhibited by DpE. These results indicate that DpE increases the chemotactic activity of THP-1 cells in response to CC chemokines by regulating the cells’ protease-dependent mechanism. This finding may be useful in identifying the pathogenesis of allergic diseases induced by Der p.