• Title/Summary/Keyword: continuum

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Chemical Differentiation of $C^{34}S$ and $N_2H^+$ in Dense Starless Cores

  • Kim, Shinyoung;Lee, Chang Won;Sohn, Jungjoo;Kim, Gwanjeong;Kim, Mi-Ryang
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.2
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    • pp.75.2-75.2
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    • 2014
  • CS molecule as an important tracer for studying inward motions in dense cores is known to be adsorbed onto dusts in cold (T~10K) dense cores, resulting in its significant depletion in the central region of the cores which may hamper a proper study of kinematics stage of star formation. In this study we choose five 'evolved' dense starless cores, L1544, L1552, L1689B, L694-2 and L1197, to investigate how depletion of CS molecule is significant and how the molecule differentiates depending on the evolutional status of the dense cores, by using a rare isotopomer C34S. We performed mapping observations in C34S (J=2-1) and N2H+ (J=1-0) with Nobeyama 45 m telescope, and compared $850{\mu}m$ continuum data as a reference of the density distribution of the dense cores. Our data confirm the claim that CS molecule generally depletes out in the central region in dense starless cores, while N2H+ keeps abundant as they get evolved. All of integrated intensity maps show 'semi-ring-like' depletion holes in CS, and all of abundance radial profiles show decrease toward center. The CS depletion and molecular chemical differentiation seems to depend on the evolutional status in dense cores. The evolved cores shows low abundance at both central and outer regions, implying that in the case of highly evolved cores CS freeze-out occurs over the most area of the cores.

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DEUTERATED METHANOL (CH3OD) IN THE HOT CORE OF THE MASSIVE STAR-FORMING REGION DR21 (OH) (무거운 별 탄생 지역인 DR21(OH) 천체에 대한 중수소화된 메탄올(CH3OD) 관측연구)

  • Minh, Young Chol
    • Publications of The Korean Astronomical Society
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    • v.29 no.2
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    • pp.29-34
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    • 2014
  • We have observed the deuterated methanol, $CH_3OD$, toward the hot core MM1 in the massive star-forming region DR21 (OH) using the Submillimeter Array with a high angular resolution of about 1 arcsecond. The position of the hot core associated with the sub-core MM1a was confirmed to coincide with the continuum peak where an embedded young stellar object is located. The column density of $CH_3OD$ was found to be about $(2{\pm}1){\times}10^{16}cm^{-2}$ toward the MM1a center. The abundance ratio $CH_3OD/CH_3OH$ was measured to be ~ 0.45, which is about the median value for low mass star-forming cores but much larger than those of the massive star-forming cores. The ratio is believed to change depending on, for example, the chemical condition, the temperature and the density of the source. This ratio may further depend on the evolutionary phase especially in the massive-star-forming cores. The sub-core MM1a is thought to be in the very early phase of star formation. This large abundance ratio found in this source indicates that even the massive star-forming cores, during a relatively short period in the very early stage of star formation, may also show a chemical state resulted from the cold and dense pre-collapsing phase, the enhanced deuteration as found in low mass star-forming cores.

Core formation in different environments: Planck Galactic Cold Clumps (PGCCs) in the λ Orionis cloud, Orion A and Orion B clouds

  • Yi, HeeWeon;Lee, Jeong-Eun;Liu, Tie;Kim, Kee-Tae;Wu, Yuefang
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.2
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    • pp.37.4-38
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    • 2016
  • Based on the $850{\mu}m$ dust continuum data from James Clerk Maxwell Telescope (JCMT)/SCUBA-2, we compare overall properties of Planck Galactic Cold Clumps (PGCCs) in the ${\lambda}$ Orionis cloud with PGCCs in other molecular clouds, Orion A and Orion B. The Orion A and Orion B clouds are well known active star-forming region, while, ${\lambda}$ Orionis cloud has a different environment associating with prominent OB associations and a giant H II region. PGCCs in the ${\lambda}$ Orionis cloud have higher dust temperatures (Td~16.08 K) and lower values of dust emissivity (${\beta}{\sim}1.65$) than Orion A and Orion B clouds. In addition, we found the lowest detection rate (16 %, 8 out of 50) of PGCCs at $850{\mu}m$ in the ${\lambda}$ Orionis cloud while among three regions; Orion A and Orion B clouds show much higher detection rates of ~ 76 % (23 out of 30) and 56 % (9 out of 16), respectively. The detected 8 PGCCs in the ${\lambda}$ Orionis cloud have substructures and we identified 15 cores. The cores also show much lower median values of size (~0.08 pc), column density (~ ), number density (~ ), and mass (~ ) compared with other cores in the Orion A and Orion B clouds. These core properties in the ${\lambda}$ Orionis cloud can be attributed to the compression and external heating by the nearby H II region, which may prevent the PGCCs from forming gravitationally bound structures and eventually disperse them. These results well present the negative stellar feedback to core formation.

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A Search for Very Low-luminosity Objects in Gould Belt Clouds

  • Kim, Mi-Ryang;Lee, Chang Won;Dunham, Michael M.;Evans, Neal J II;Kim, Gwanjeong;Allen, Lori E
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.2
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    • pp.38.3-39
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    • 2016
  • We present the results of a search for Very Low-Luminosity Objects (VeLLOs) in the Gould Belt (GB) clouds using infrared and sub-millimeter (sub-mm) data from 1.25 to $850{\mu}m$ and our N2H+ (J = 1-0) observations. We modified the criteria by Dunham et al. to select the VeLLOs in the GB clouds, finding 95 VeLLO candidates, 79 of which are newly identified in this study. Out of 95 sources, 44 were detected in both sub-mm continuum and N2H+ emission and were classified as Group A (the VeLLOs), and 51 sources detected in either sub-mm emission or N2H+ emission were classified with Group B as candidate VeLLOs. We find that these VeLLOs and the candidates are forming in environments different from those of the likely VeLLOs. Seventy-eight sources are embedded within their molecular clouds, and thus are likely VeLLOs forming in a dense environment. The remaining 17 sources are located in low-level extinction regions (Av < 1) connected to the clouds, and can be either background sources or candidate substellar objects forming in an isolated mode. The VeLLOs and the candidates are likely more luminous and their envelopes tend to be more massive in denser environments. The VeLLOs and the candidates are more populous in the clouds where more YSOs form, indicating that they form in a manner similar to that of normal YSOs. The bolometric luminosities and temperatures of the VeLLOs are compared to predictions of episodic accretion models, showing that the low luminosities for most VeLLOs can be well explained by their status in the quiescent phases of a cycle of episodic mass accretion.

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A Study on the Relationships Between the chief Nurse′s Leadership style and the organizational climate of Hospitals (간호과장의 지도성 유형과 병원 조직풍토와의 관계)

  • 김영매;한상임
    • Journal of Korean Academy of Nursing
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    • v.5 no.1
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    • pp.79-86
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    • 1975
  • It had been thought the role of Nursing administrator was still not started along the right line in Korea because of the Lacking of full understanding and recognition of the real meaning of administrator's role, and because there are several Rinds of problems and difficulties in actual role. The present study is an attempt to clarify some existing relationships between the chief Nurse's Leadership style and the organizational climate of Hospitals. The problems of the study are specifically started as follows ; 1) What influence does the individual behavior have on the formation of the organizational climate of Hospital? 2) From what do the difference of climate arise? 3) How are the individual be heavier and organizational climate of Hospital measured ? In order to see the relationships or the interactions between the two factors, the chief nurse's Leadership style and organizational climate of hospital , the researcher has classified. He former into; 1) effective Leadership style. 2) initiating structure leader ship style. 3) Consideration structure Leadership style, and 4) ineffective Leadership style, and the latter in to. 1) open climate and 2) closed climate The Chief Nurses Leadership style has been. Classified into consideration-human relations approaches and initiating structure approaches according to L. B. D. Q by Hapin. Organizational climate of hospital has been classified into open-closed continuum according to O. C. H Q. by Hairpin and Croft. The results obtained are as follows : 1) The chief nurse's Leadership style is closer to Initiating structure Leadership style than Consideration structure lure Leadership style. 2) The organizational climate of hospital is closer to open climate than closed climate. 3) The chief nurse's Leadership sty]e and the organizational climate of hospital to not show any significant relations.

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A Parametric Study to Estimate the Behavior of a Piled Raft Foundation Influenced by Ground Conditions (지반조건이 Piled Raft 기초의 거동에 미치는 영향 평가를 위한 매개변수 연구)

  • You, Kwang-Ho;Jung, Yeun-Hak
    • Journal of the Korean Geotechnical Society
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    • v.32 no.8
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    • pp.35-46
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    • 2016
  • In this study, a sensitivity analysis was carried out by using numerical analysis under the consideration that it is difficult to analyze the behavior of real piled raft foundations on different ground conditions through a real scale test. The program used for numerical analysis is FLAC 3D based on the finite difference method. Piles were modelled by using pile element that is one of the structure elements of FLAC 3D and the ground and raft were modelled by using continuum element. With a fixed pile arrangement of $3{\times}3$, the diameter, length, space of piles, and ground conditions were selected as sensitivity parameters and their mutual correlation were investigated. As a result, the bigger and longer pile diameter, length and pile space are, the bigger the bearing capacity of the piled raft becomes. When pile space exceeded a specific value, however, the piled raft foundation behaved like a shallow foundation supported by only a raft. Also it can be confirmed that the better ground conditions are, the more total bearing capacity of the piled raft foundation increases.

The Seasonal Impacts of De-icing Salts on Soil and Vegetation in Chung-ju City (충주시 가로변 토양과 가로수 식생에 미치는 계절별 제설제의 영향)

  • Kim, Jae-Young;Park, Ju-Young;Yoon, Young-Han;Ju, Jin-Hee
    • Journal of Environmental Science International
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    • v.26 no.8
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    • pp.993-998
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    • 2017
  • De-icing salts applied to roads during winter enable safe driving conditions. However, these salts are eventually displaced to roadside areas at which they can negatively impact soil, vegetation, and water resources. This purpose of this study is to determine the relationship between foliar damage ratio (NY = 0-25%, SY = 26-50%, CY = 51-75%) on roadside trees (Ginko biloba) and seasonal impact of de-icing salts on soil and vegetation. Thirty roadside trees were selected at 8 m intervals between the Konkuk and Judeok intersections in Chung-ju city. The results reveal that seasonal soil acidity is relatively alkaline for foliar damage ratio of Ginko biloba was CY compared to NY. Also, electronic conductivity of each seasonal sampling was recorded as high in winter and spring, whereas the opposite trend is observed in summer. Various plants species were identified in abundance under roadside trees within NY roadside sections. These same species were observed in reduced numbers within CY sections. Strong negative correlations were identified between foliar damage ratio on roadside trees and vegetation. This relationship may be a method to use in predicting the accumulation of de-icing salt and visible injuries on roadside trees.

Korean /l/-flapping in an /i/-/i/ context

  • Son, Minjung
    • Phonetics and Speech Sciences
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    • v.7 no.1
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    • pp.151-163
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    • 2015
  • In this study, we aim to describe kinematic characteristics of Korean /l/-flapping in two speech rates (fast vs. comfortable). Production data was collected from seven native speakers of Seoul Korean (four females and three males) using electromagnetic midsagittal articulometry (EMMA), which provided two dimensional data on the x-y plane. We examined kinematic properties of the vertical/horizontal tongue tip gesture, the vertical/horizontal (rear) tongue body gesture, and the jaw gesture in an /i/-/i/ context. Gestural landmarks of the vertical tongue tip gesture are directly measured. This serves as the actual anchoring time points to which relevant measures of other trajectories referred. The study focuses on velocity profiles, closing/opening spatiotemporal properties, constriction duration, and constriction minima were analyzed. The results are summarized as follows. First, gradiently distributed spatiotemporal values of the vertical tongue tip gesture were on a continuum. This shows more of a reduction in fast speech rate, but no single instance of categorical reduction (deletion). Second, Korean /l/-flapping predominantly exhibited a backward sliding tongue tip movement, in 83% of production, which is apparently distinguished from forward sliding movement in English. Lastly, there was an indication of vocalic reduction in fast rate, truncating spatial displacement of the jaw and the tongue body, although we did not observe positional variations with speech rate. The present study shows that Korean /l/-flapping is characterized by mixed articulatory properties with respect to flapping sounds of other languages such as English and Xiangxiang Chinese. Korean /l/ flapping demonstrates a language-universal property, such as the gradient nature of its flapping sounds that is compatible with other languages. On the other hand, Korean /l/-flapping also shows a language-particular property, particularly distinguished from English, in that a backward gliding movement occurs during the tongue tip closing movement. Although, there was no vocalic reduction in V2 observed in terms of jaw and tongue body height, spatial displacement of these articulators still suggests truncation in fast speech rate.

Development and Evaluation of a Navigation Program for Newly Diagnosed Cancer Patients (암을 처음 진단받은 환자를 위한 신환 네비게이션 프로그램 개발 및 효과 평가)

  • Kwon, In Gak;Hong, Jin Young;Baek, Hye Jin;Kim, Sung;Nam, Seok Jin;Kim, Im Ryung;Kim, Hye Jung;Kim, Ae Ran
    • Journal of Korean Clinical Nursing Research
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    • v.18 no.1
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    • pp.111-125
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    • 2012
  • Purpose: The purposes of this study were to develop a navigation program for newly diagnosed cancer patients and to evaluate its effects. Methods: The navigation program was based upon Professional Navigation Framework. Patients were asked to complete self-administered questionnaires on satisfaction, distress, anxiety and depression for evaluating the program. Results: The navigation program consisted of facilitating two concepts: continuity of care and empowerment of patients. Information-education package, telephone counseling and navigator's phone number were provided to the newly diagnosed cancer patients for care continuity. Self-care diary and emotional support by telephone counseling were provided to the patients for empowerment of patients. A total of 163 patients - 78 control and 85 experimental participants - were included in the study. The mean scores of satisfaction, distress, anxiety and depression had no statistical differences between the two groups after program implementation. In patients with longer waiting days, the experimental group with the navigation program showed higher relational continuity than the control group after program implementation(p=.023). In patients with longer waiting days or with higher distress, satisfaction of relational continuity was improved after program implementation in the experimental group. Conclusion: The navigation program in this study has applied the concept of patient navigation into oncology clinical setting in Korea. Navigation program can play a significant role in assisting patients navigating across the care continuum.

The Relationships Between Perception of Supervisors' Autonomy Support, Volunteer Motivation and Persistence Intentions Among Collegiate Volunteers (대학생 자원봉사자가 지각한 슈퍼바이저의 자율성지지, 자원봉사동기 및 지속의도 간의 관계 분석)

  • Hong, Yeon-Sook
    • Korean Journal of Social Welfare
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    • v.62 no.4
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    • pp.103-128
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    • 2010
  • This study applied self-determination theory to investigate the relationships between volunteers' perception of supervisors' autonomy support, volunteering motivation, and persistence intentions among collegiate students. Collegiate volunteers(n=515) involved in volunteer activities completed measures of supervisors' autonomy support, 5 forms regulation, and persistence intentions. Bivariate correlations indicated that volunteer motivation demonstrated an ordered pattern of relationships, such that adjunct points along the regulatory continuum would be more positively associated with on another than distal points. Analyses using structural equation modeling revealed that supervisors' autonomy support was positively related to more autonomous motivation(intrinsic motivation and identified regulation), while was natively associated with amotivation. Amotivation was negatively related with persistence intentions, and more autonomous motivations(intrinsic and identified) predicted grater intentions to continue with volunteer activity for next 6 months. The findings are discussed in light of the self-determination theory.

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