• Journal of Ginseng Research
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• 제20권3호
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• pp.256-261
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• 1996

Comparative biological activities of 70fr methanol extracts from the main roots and rhizomes of both red and white ginsengs were investigated using several in vitro experimental models. The main root of red ginseng and the rhizome of white ginseng strongly inhibited lipld peroxidation of hepatic microsomes induced by the non-enzymatic $Fe^{+}$ / Ascorbate system. The main root and rhizome of red ginseng markedly inhibited the release of G07, GPT and LDH by $CCl_4$-induced cytotoxicity in primary cultured rat hepatocytes as compared with those of white ginseng. And also, the main root of red ginseng showed a slight differentiating activity on HL-60 cancer cell line. The results suggest that the rhizome of ginseng have potential as a source of medicinal crude drug with possible pharmacolobica1 applications .

• 한국생산제조학회지
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• 제20권4호
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• pp.407-411
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• 2011

The technology of line heating has evolved in various methods. Among them, fossil fuels like ethylene gas and LPG(Liquid Petroleum Gas) are widely used due to their simple utility. In the meantime, the technology implementing high frequency for line heating has also been developed continually, but its manufacturing technology or application includes lots of problems by now. One of the main characteristics of line heating using conventional technolob'Y is the quenching effect followed by heating process. On the other hand, hydrox gas which is mixed by hydrogen and oxygen is a prominent candidate for an application without above shortcomings. Especially, it is found that line heating using hydrox gas is tremendously effective taking low cost as well as low noise. In this paper, a small cell with high efficiency which can minimize installing space is developed to deal with the problem installing in narrow place. Experiments to prove the validation, efficiency and effectiveness is carried out by characterizing in the line heating of steel. It is found that the energy saving of using hydrox gas for line heating is significant and that the deviation performance is reduced by 78~89%. Furthermore, the noise is also reduced as amount of 18.3% though the heating time is not too different.

• Wind and Structures
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• 제18권5호
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• pp.473-495
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• 2014

Localized wind events, in the form of tornadoes and downbursts, are the main cause of the large number of failure incidents of electrical transmission line structures worldwide. In this study, a numerical model has been developed to study the behaviour of self-supported transmission lines under various tornado events. The tornado wind fields used were based on a full three-dimensional computational fluid dynamics analysis that was developed in an earlier study. A three-dimensional finite element model of an existing self-supported transmission line was developed. The tornado velocity wind fields were then used to predict the forces applied to the modelled transmission line system. A comprehensive parametric study was performed in order to assess the effects of the location of the tornado relative to the transmission line under F2 and F4 tornado wind fields. The study was used to identify critical tornado configurations which can be used when designing transmission line systems. The results were used to assess the sensitivity of the members' axial forces to changes in the location of the tornado relative to the transmission line. The results were then used to explain the behaviour of the transmission line when subjected to the identified critical tornado configurations.

• 유통과학연구
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• 제15권10호
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• pp.81-92
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• 2017

Purpose - One of the main objectives of this paper is to identify the most effective type of social media and to analyze the priority of blogs by their informational attributes in the aspect of their impacts on word-of-mouth intention(WOM) in on-line markets. Research design, data, and methodology - We set 'attitude' variable in the middle to see if there is mediating effects between blog information and word-of-mouth intention. We conducted a survey by questionnaire and received 206 answers. Employing the OLS statistical methods through the SPSS package, we tested our hypotheses. Results - Some of the main results are the followings. First, blog, micro-blog, and profile-based services showed significant effects on WOM, while Internet community and mini-homepages are not significant. Second, blog has positive impacts on WOM. Third, attitude has perfect mediating effects between blog and WOM. Fourth, in terms of effects on WOM, interactivity shows the first priority and reliability and usability follows. Finally, attitude has a more significant effect for users of 3 types of blog compared with those of 2 types. Conclusions - In this paper, we analyzed the effects of social network services by type and identified the priority among various attributes of information contained in blogs. It would provide businesses with viable strategic options to establish public relations in their sales promotion.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.361-364
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• 2005

Some bogie frames manufactured in 1999, 2000 year have the fatal problem. Three or four years later, the cracked end beam among them have discovered in 2002, 2003 year. The crack situation of the end beam have a bad effect on brake system. In that case, the cars would be in danger of derailment. To improve the end beam, a research of covering the whole field of welded type bogie frame was started. Main line real tests were performed at Young-Dong line. The stress of main positions for bogie frame was measured. Also up-down direction and left-right direction vibration acceleration of the bogie frame were measured. At this time the tests were performed for the three types bogie. The test result concludes that the crack cause of the end beam is not brake load but vibration at running mainly. It is estimated that the life of the improved car which end beam reinforced is safe within the car permitted life(25 years). The improvement methods of the end beam are presented by construction modification, parts modification. The integrity evaluation is inspected by analysis the real line test results, the improvement methods of the end beam.

• 한국지구과학회지
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• 제36권5호
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• pp.419-426
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• 2015

We investigated the high dispersion spectra that had been secured at the center of the planetary nebula NGC 7027 with the Bohyunsan Optical Echelle Spectrograph (BOES) on October, 20, 2009. We analyzed the forbidden lines of [OI], [SII], [OII], [NII], [ClIII], [ArIII], [OIII], [ArIV], [NeIII], [ArV], and [CaV] in the $3770-9225{\AA}$ wavelength region. The expansion velocities were derived from double Gaussian line profiles of the emission lines, after eliminating the subsidiary line broadening effects. The radial variations of the expansion velocities were obtained by projecting the derived expansion velocities: $19.56-31.93kms^{-1}$ onto the equatorial shell elements of the inner and the outer boundaries of the main shell of 2.5(2.1)" and 3.8(3.6)", according to the ionization potential of each ion. Analysis of equatorial shell spectra indicated that the equatorial shell generally expands in an accelerated velocity mode, but the expansion pattern deviates from a linear velocity growth with radial distance. NGC 7027, of which age is about 1000 years or less, might be still at its early stage. During the first few hundred years, plausibly in its early stage, the main shell of PN expands very slowly and, later, it gradually gain its normal expansion speed.

• 천문학논총
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• 제15권spc1호
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• pp.133-145
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• 2000

Symbiotic stars are known as binary systems with both cool and hot components with enshrounding nebulous gas. The cool component, M-type giant, is presumably loosing its mass into a hot white or main sequence companion star through the inner Lagrangian point. The lines emit from the ionized nebulous region around the hot star while the mass loss or accretion activity is believed to be the main cause of sudden variation of the continuum and line fluxes. We selected 17 symbiotics for which the emission line fluxes were measured from the IUE SWP, LWR data, to find variability of spectrum. We also investigated the periodic variation of emissions or eclipsing effect from the IUE lines. All of our symbiotics show very high electron densities in the emission regions. For other optical symbiotics, the observations had been carried in 1999 with BOAO mid-resolution spectrometer. We classified symbiotics based on their outburst activities, or emission line characteristics, i.e., $OVI{\lambda}6830.\;The\;OVI{\lambda}6830$ emission lines are also found in S-type symbiotics, which have been known as charateristics of D-types.

• Nuclear Engineering and Technology
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• 제32권3호
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• pp.214-226
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• 2000

In an effort to assess the performance of KAERI's coupled 3D kinetics - system T/H code, MARS/MASTER, Exercise III of the OECD main steam line break benchmark is solved. The analysis model of the reference plant, TMI-1 - a 2772 MWth B&W plant, consists of three major components: a core neutronics model involving 241$\times$28 neutronic nodes, a vessel 3D T/H model consisting of 374 hydrodynamic volumes, and a 1D system T/H model containing 157 hydrodynamic volumes. The results show that there is a significant amount of flow mixing occurring in the upper and lower plenum regions and the core power distribution evolves to a highly localized shape due to the presence of a stuck rod, as well as the asymmetric flow distribution. It is judged that MARS/MASTER properly captures these drastic 3-dimensional effects. Comparisons with other results submitted to OECD confirm the accuracy of the MARS/MASTER solution.

• 한국지역지리학회지
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• 제10권1호
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• pp.158-176
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• 2004

본 연구는 오프라인을 기반으로 한 인터넷 쇼핑몰의 유통체계와 상품판매의 공간적 특성을 밝히는 것이 목적이다. 본 사례업체의 유통체계는 크게 메이커에서의 상품 선정과정과 소비자로의 상품 배송과정으로 구분된다. 이는 물류센터의 기능과 역할을 모두 위탁한 결과이다. 또한 오프라인인 백화점과 구별된 물류시스템을 이용하고 있으며 비용절감과 보다 빠른 배송을 위해 배송부문을 택배사에 외부수주하고 있다. 배송권별 상품판매의 특성을 살펴보면 본사가 입지한 배송권에 상품판매가 집중적으로 이루어지는 형태를 보인다. 이는 오프라인을 기반으로한 인터넷 쇼핑몰이 공간의 제약을 완전하게 극복한 통신판매가 아님을 말해 주는 것이다. 또한 지역별 상품 판매에 영향을 미치는 공간적 분포 요인은 20$\sim$49세의 여성인구수와 거리임이 밝혀졌다.

• 한국추진공학회지
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• 제25권2호
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• pp.110-118
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• 2021

액체로켓엔진의 구성품인 연소기 산화제 개폐밸브는 연소기에 공급되는 산화제를 제어한다. 밸브가 닫힐 때 산화제는 연소기 대신 재순환 유로로 공급되며, 이때 발생한 수격현상에 의해 설계 기준보다 큰 압력이 발생할 수 있다. 본 연구에서는 액체질소를 운용 유체로 사용하여 재순환 유로의 초기 조건에 따른 수격 시험을 수행하였으며, 그 결과 발생하는 압력파를 분석하였다. 초기 조건에 따라 재순환유로 내부 압력파의 경향이 달랐으며, 특히 재순환 유로 끝단에서는 응축에 의한 수격이 발생할 때 압력이 최대로 커질 수 있음을 확인하였다.