• 한국지역지리학회지
• /
• 제19권1호
• /
• pp.130-146
• /
• 2013

이 글은 다크투어리즘의 일환인 재난관광이 지닌 포스트모더니즘적 특성에 주목하여, 진정성 문제를 통해 이를 분석하는 것을 목적으로 하였다. 이를 위해 지난 2011년 발생한 동일본대지진을 구체적 사례로 선정하여, 재난관광의 전개 과정을 분석하였다. 재난 직후, 관광의 영역은 해체되고 일시적으로 재해 공동체가 형성된다. 이후 사회공헌형 관광이 등장하는데, 이 속에서 게스트(관광객)와 호스트(현지주민)는 모두 삶과 죽음의 문제를 공유하게 되고, 실존적 진정성은 관광동기와 경험에서 핵심요소가 된다. 그러나 시간이 지나면서 실존적 진정성은 재해재건의 정치경제적 맥락 속에서 이데올로기적으로 재편되고, 구성적 진정성으로 대체됨으로써 반근대적 성찰에 기반한 대안관광이라는 재난관광의 가능성에 한계가 나타나게 된다. 재난관광의 상품화 이면에 존재하는 윤리적 이슈를 고찰하기 위해서는 재난관광을 진정성 및 포스트모더니즘의 대안관광 틀 속에서 고찰하는 실증연구가 지속되어야 할 것이다.

• 한국의류학회지
• /
• 제18권2호
• /
• pp.221-233
• /
• 1994

In several literature in China were recorded various species of the indigo genus, but in Chosen documents, the two have been intensively mentioned, that is, Polygonum tinctorium (PT) and liatis Tinctuna(IT). Allowing for some slight contradictions of the records between the two countries, we insist that J)T is the aborigines historically longer than any other indigo plant in Korea and that IT is the one Implanted from China in late Chosen period. Indigos can be grouped into two major categories : 'Chon' or Indigo forming sediment in the course of making, and 'Nam' or the one without. The dyestuffs of blue, or dark blue tineged with red, which had been ocasionally recorded until the mid Chosen, could be made from the . species without sediment. The period when the color thus obtained was prevalent can be traced back to the era of Yongio, when the import of blue-dyed textiles from China was prohibited to encourage the domestic dyeing industry. However, a more clarification is needed on this matter, since all of the previous researches are arguing, with little validity, that the indigo genus in Korea be PT. Judging from the documents recording that PT did not form any sediment, and that from it was obtained only light color like indigo, it is a matter of re-discussion in terms of botanical taxonomy to define as PT the species being cultivated in some areas in Chollanam-do. In conclusion, a joint research, including specialists in traditional dyestuffs and in botany in relation to the taxonomical problem of the indigo genus, would be expected for further Investigation on this matter.

• 천문학회지
• /
• 제50권3호
• /
• pp.61-70
• /
• 2017

We study the angular correlation function of bright ($K_s{\leq}19.5$) Extremely Red Objects (EROs) selected in the Subaru GTO 2$deg^2$ field. By applying the color selection criteria of $R-K_s$ > 5.0, 5.5, and 6.0, we identify 9055, 4270, and 1777 EROs, respectively. The number density is consistent with similar studies on the optical - NIR color selected red galaxies. The angular correlation functions are derived for EROs with different limiting magnitude and different $R-K_s$ color cut. When we assume that the angular correlation function $w({\theta})$ follows a form of a power-law (i.e., $w({\theta})=A{\theta}^{-{\delta}}$), the value of the amplitude A was larger for brighter EROs compared to the fainter EROs. The result suggests that the brighter, thus more massive high-redshift galaxies, are clustered more strongly compared to the less massive galaxies. Assuming that EROs have redshift distribution centered at ~ 1.1 with ${\sigma}_z=0.15$, the spatial correlation length $r_0$ of the EROs estimated from the observed angular correlation function ranges ${\sim}6-10h^{-1}Mpc$. A comparison with the clustering of dark matter halos in numerical simulation suggests that the EROs are located in most massive dark matter halos and could be progenitors of $L_{\ast}$ elliptical galaxies.

• 천문학회보
• /
• 제42권2호
• /
• pp.41.2-41.2
• /
• 2017

Discovered as the second highest S/N detection of the Planck SZ survey, PLCK G287.0+32.9 is a massive galaxy cluster that belongs to a rare collection of merging clusters that exhibit two radio relics and a radio halo. A feature that makes this cluster even more unique is the separation of the radio relics with one $\sim 400$ kpc to the north-west of the X-ray peak and the other $\sim 2.8$ Mpc to the south-east. This asymmetric configuration requires a complex merging scenario. A key to gaining insight into the events that caused the formation of the merging features is to understand the dark matter mass distribution. Using a weak-lensing technique on deep Subaru and Hubble Space Telescope observations, we map the dark matter mass distribution of PLCK G287.0+32.9. Our investigation detects five significant mass structures. The mass is dominated by a primary structure that is centered near the X-ray peak of the intracluster medium. Four lesser mass structures are detected with two located within $\sim 1\arcmin$ of the primary mass structure, a third to the north-west, and a fourth near the south-east radio relic. Along with these detections, we estimate the mass of each structure and relate their distributions to the intracluster medium and galaxy distributions. In addition, we discuss the relation of the mass structures to the formation of the relics and plausible merging scenarios.

• 천문학회지
• /
• 제46권3호
• /
• pp.133-140
• /
• 2013

The empirical mass discrepancy-acceleration (MDA) relation of disk galaxies provides a key test for models of galactic dynamics. In terms of modified laws of gravity and/or inertia, the MDA relation quantifies the transition from Newtonian to modified dynamics at low centripetal accelerations $a_c{\lesssim}10^{-10}ms^{-2}$. As yet, neither dynamical models based on dark matter nor proposed modifications of the laws of gravity/inertia have predicted the functional form of the MDA relation. In this work, I revisit the MDA data and compare them to four different theoretical scaling laws. Three of these scaling laws are entirely empirical; the fourth one - the "simple ${\mu}$" function of Modified Newtonian Dynamics - derives from a toy model of gravity based on massive gravitons (the "graviton picture"). All theoretical MDA relations comprise one free parameter of the dimension of an acceleration, Milgrom's constant aM. I find that the "simple ${\mu}$" function provides a good fit to the data free of notable systematic residuals and provides the best fit among the four scaling laws tested. The best-fit value of Milgrom's constant is $a_M=(1.06{\pm}0.05){\times}10^{-10}ms^{-2}$. Given the successful prediction of the functional form of the MDA relation, plus an overall agreement with the observed kinematics of stellar systems spanning eight orders of magnitude in size and 14 orders of magnitude in mass, I conclude that the "graviton picture" is sufficient (albeit probably not a necessary nor unique approach) to describe galactic dynamics on all scales well beyond the scale of the solar system. This suggests that, at least on galactic scales, gravity behaves as if it was mediated by massive particles.

• 천문학회보
• /
• 제41권1호
• /
• pp.38.2-38.2
• /
• 2016

The mapping of dark matter clustering from real to redshift spaces introduces the anisotropic property to the measured density power spectrum in redshift space, known as the Redshift Space Distortion (hereafter RSD) effect. The mapping formula is intrinsically non-linear, which is complicated by the higher order polynomials due to the indefinite cross correlations between the density and velocity fields, and the Finger-of-God (hereafter FoG) effect due to the randomness of the peculiar velocity field. Furthermore, the rigorous test of this mapping formula is contaminated by the unknown non-linearity of the density and velocity fields, including their auto- and cross-correlations, for calculating which our theoretical calculation breaks down beyond some scales. Whilst the full higher order polynomials remains unknown, the other systematics can be controlled consistently within the same order truncation in the expansion of the mapping formula, as shown in this paper. The systematic due to the unknown non-linear density and velocity fields is removed by separately measuring all terms in the expansion using simulations. The uncertainty caused by the velocity randomness is controlled by splitting the FoG term into two pieces, 1) the non-local FoG term being independent of the separation vector between two different points, and 2) the local FoG term appearing as an indefinite polynomials which is expanded in the same order as all other perturbative polynomials. Using 100 realizations of simulations, we find that the best fitted non-local FoG function is Gaussian, with only one scale-independent free parameter, and that our new mapping formulation accurately reproduces the observed power spectrum in redshift space at the smallest scales by far, up to k ~ 0.3 h/Mpc, considering the resolution of future experiments.

• 천문학회보
• /
• 제44권1호
• /
• pp.39.2-39.2
• /
• 2019

Galaxy clusters are the largest gravitationally bound structures in the universe and located in the densest peak of the dark matter. They can constraint cosmologicals model from their dark matter halo distribution and they are good laboratories to study how galaxy evolution varies with their environment. Especially, studies of galaxy clusters at $z{\geq}1$ are important because (i) galaxy evolution at z >1 is still controversial (Elbaz et al. 2007; Faloon et al. 2013) and (ii) some studies show that mass of galaxy clusters at z>1 seems to be higher than expected value from the concordance LCDM cosmological model (Kang & Im 2009; Gonzales et al. 2012). In spite of their significance, there have not been many studies of galaxy clusters at $z{\geq}1$ because of the lack of wide and deep multi-wavelength data. We newly found galaxy cluster candidates at 0.2 < z < 1.4 and a LSS spanning over 100Mpc at z~0.9 in the ELAIS-N1 field which is one of the IMS (Infrared Medium-deep Survey; Im et al. 2019, in preparation) fields. Thanks to K-GMT science program, we performed spectroscopic follow-up observation for a z~1 galaxy cluster candidates with GMOS of Gemini North and for z~0.9 supercluster candidates with Hectospec of MMT in 2018A and confirmed the large scale structures. We present the newly discovered galaxy overdensities from the observation and the analysis result.

• Journal of Ginseng Research
• /
• 제22권3호
• /
• pp.161-167
• /
• 1998

American ginseng plants (Panax quinquefolium L.) of various ages were harvested every two weeks during each of three growing seasons and dry matter yield of components and root respiration determined. Shoot dry weight was about 0.5 g, 2.5 g and 4 g for 2, 3 and 4-year-old plants, respectively and fruit dry weight was as much as 50% of this in 3- and 4-year-.old plants. Root dry weight decrease by 30~50% as shoots emerged and at the end of the season was about 2 g, 3.5 g and 5 g in 2, 3, 4 and 5-year-old plants, respectively. Shoot and root dry weight were linearly related with an approximate 1:2 ratio. Root respiration rate at 2$0^{\circ}C$ in the dark was about 5 $\mu\textrm{g}$ CO2 g-1 DW(dry weight) min-1 in the early season, then doubled within 50 days as shoots emerged, and thereafter declined over the season to 2~5 $\mu\textrm{g}$ CO2 g-1 DW min-1. The Q10 for dark respiration over the interval from 10 to 2$0^{\circ}C$ was 1.58. Root respiration rate and shoot growth rate was positively linearly related in all ages of plants. Key words: Dry weight, partitioning.

• 천문학회보
• /
• 제43권1호
• /
• pp.61.3-61.3
• /
• 2018

To understand the assembly of the galaxy population in clusters today, it is important to first understand the impact of previous environments prior to cluster infall, namely preprocessing. We use 15 cluster samples from hydrodynamic zoom-in simulation YZiCS to determine the significance of preprocessing focusing primarily on the tidal mass loss of dark matter halos. We find ~48% of the cluster member halos were once satellites of another host. The preprocessed fraction is not a clear function of cluster mass. Instead, we find it is related to each individual cluster's recent mass growth history. We find that the total mass loss is a clear function of time spent in a host. However, two factors can considerably increase the mass loss rate. First, if the satellite mass is approaching the mass of its host. Second, when the halo suffers tidal mass loss at a higher redshift. The preprocessing provides an opportunity for halos to experience tidal mass loss for a more extended period of time than would be possible if they simply fell directly into the cluster, and at earlier epochs when hosts were more destructive to their satellites.

• Advances in aircraft and spacecraft science
• /
• 제7권3호
• /
• pp.251-269
• /
• 2020

Euclid is an optical/near-infrared survey mission of the European Space Agency (ESA) to investigate the nature of dark energy, dark matter and gravity by observing the geometry of the Universe and the formation of structures over cosmological timescales. The Euclid spacecraft mechanical architecture comprises the Payload Module (PLM) and the Service Module (SVM) connected by an interface structure designed to maximize thermal and mechanical decoupling. This paper shortly illustrates the mechanical system of the spacecraft and the mechanical verification philosophy which is based on the Structural and Thermal Model (STM), built at flight standard for structure and thermal qualification and the Proto Flight Model (PFM), used to complete the qualification programme. It will be submitted to a proto-flight test approach and it will be suitable for launch and flight operations. Within the overall verification approach crucial mechanical tests have been successfully performed (2018) on the SVM platform and on the sunshield (SSH) subsystem: the SVM platform static test, the SSH structure modal survey test and the SSH sine vibration qualification test. The paper reports the objectives and the main results of these tests.