• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.263-263
• /
• 2013

This work examines the dynamic properties of ice surfaces in vacuum for the temperature range of 140~180 K, which extends over the onset temperatures for ice sublimation and the phase transition from amorphous to crystallization ice. In particular, the study focuses on the transport processes of excess protons and chloride ions in ice and their segregative behavior to the ice surface. These phenomena were studied by conducting experiments with a relatively thick (~100 BL) ice film constructed with a bottom $H_2O$ layer and an upper $D_2O$ layer, with excess hydronium and chloride ions trapped at the $H_2O$/$D_2O$ interface as they were generated by the ionization of hydrogen chloride. The migration of protons, chloride ions, and water molecules to the ice film surface and their H/D exchange reactions were measured as a function of temperature using the methods of low energy sputtering (LES) and Cs+ reactive ion scattering (RIS). Temperature programmed desorption (TPD) experiments monitored the desorption of water and hydrogen chloride from the surface. Our observations indicated that both hydronium and chloride ions migrated from the interfacial layer to segregate to the surface at high temperature. Hydrogen chloride gas desorbs via recombination reaction of hydronium and chloride ions floating on the surface. Surface segregation of these species is driven by thermodynamic potential gradient present near the ice surface, whereas in the bulk, their transport is facilitated by thermal diffusion process. The finding suggests that chlorine activation reactions of hydrogen chloride for polar stratospheric ice particles occur at the surface of ice within a depth of at most a few molecular layers, rather than in the bulk phase.

• The Journal of the Korea Contents Association
• /
• v.11 no.12
• /
• pp.307-316
• /
• 2011

The objective of this study is to figure out some specific features that were found during the adaptation process of migrant women by marriage to their local community, and also to elicit certain practical implications to facilitate their adaptation, based on the findings. For data collection, in-depth interviews were conducted with eight migrant women by marriage and the interviews were tape-recorded for transcription. For analysis, phenomenological method, particularly, Colaizzi method was adopted, by which meaningful statements in the data were categorized into themes and theme clusters. A total of 7 thematic unts, 17 themes and 47 meanings were elicited from the analysis and these 7 thematic units were "reinforcement of inner capability"; "cultural assimilation"; "to be a limited benefit receiver"; "no human network"; " impossible to be optimistic about future"; "hoping to reside in their local community"; "possible to leave Korea." Finally, this study suggested the implications for social welfare practices to facilitate the adaptation of immigrant women by marriage in their local community.

• Ocean and Polar Research
• /
• v.39 no.4
• /
• pp.257-267
• /
• 2017

Although Pacific mackerel (Scomber japonicus) is an important commercial species in Korea, its recruitment mechanism remains largely unknown. Diel vertical positioning of larvae in the water column, which is affected by their specific gravity and the surrounding water density, may help to provide an understanding on recruitment success through predator avoidance and prey availability. The specific gravity measurement on Pacific mackerel eggs and larvae would seem to be essential information necessary to learn about the transport process from spawning to nursery grounds, and consequently the recruitment success. Eggs were artificially fertilized, and larvae were fed with rotifer when their mouths opened 3-4 days after hatching. We conducted the experiment using a density gradient water column to measure the ontogenetic changes in specific gravity from fertilization to 10 days after hatching. Egg specific gravity was stable during most of the embryonic period, but a sudden increase to $1.0249g\;cm^{-3}$ happened just before hatching. However, the specific gravity of newly hatched larvae was much lighter ($1.0195g\;cm^{-3}$), and specific gravity tended to increase continuously after hatching. Comparison of specific gravity with seawater density reveals that eggs and newly hatched larvae can float in the surface layer of the ocean. For the later period of the experiment, the specific gravity showed a cyclic diel pattern: the highest in the evening while the lowest at dawn. The fullness of larval stomach may be responsible for the observed differences in specific gravity, because stomach fullness was lower (40-60%) at midnight, and higher (80-85%) in evening. The diel pattern of specific gravity might provide clues regarding how larvae match the diel vertical migration of prey organisms.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.18 no.spc
• /
• pp.75-87
• /
• 2020

The Korea Atomic Energy Research Institute (KAERI) has developed geological repository systems for the disposal of high-level wastes and spent nuclear fuels (SNFs) in South Korea. The purpose of the most recently developed system, the improved KAERI Reference Disposal System Plus (KRS⁺), is to dispose of all SNFs in Korea with improved disposal area efficiency. In this paper, a system-level safety assessment model for the KRS⁺ is presented with long-term assessment results. A system-level model is used to evaluate the overall performance of the disposal system rather than simulating a single component. Because a repository site in Korea has yet to be selected, a conceptual model is used to describe the proposed disposal system. Some uncertain parameters are incorporated into the model for the future site selection process. These parameters include options for a fractured pathway in a geosphere, parameters for radionuclide migration, and repository design dimensions. Two types of SNF, PULS7 from a pressurized water reactor and Canada Deuterium Uranium from a heavy water reactor, were selected as a reference inventory considering the future cumulative stock of SNFs in Korea. The highest peak radiological dose to a representative public was estimated to be 8.19×10^-4 mSv·yr^-1, primarily from ¹²⁹I. The proposed KRS⁺ design is expected to have a high safety margin that is on the order of two times lower than the dose limit criterion of 0.1 mSv·yr^-1.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.12
• /
• pp.6186-6195
• /
• 2013

The aim of this study was to learn what directions need to be reflected when establishing the next-term trial plans by analyzing the current trial plans being implemented in Korea regarding job training and employment support for immigrant women by marriage. For this purpose, the job training suggested in the Healthy Family Basic Plan and Multicultural Family Policy Basic Plan as well as in the Basic Economic Activity Stimulation Plans for Out-of-employment Women were analyzed. Based on this, job training was reconstructed into four categories: 1) education and training program; 2) human resource development; 3) employment support; and 4) delivery system. For the analysis, the policy analysis methods reported by N. Gilbert and P.Terrile were used. The results showed that the current trial plans exhibited immaturity in the Tomorrow Learning Card and Successful Employment Package as well as in the specialization process, lack of a human resource development system, and the absence of governance. Several proposals should consider these when making the next-term trial plans.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.2
• /
• pp.238-244
• /
• 2010

Rhizobia are well-known for their ability to infect and nodulate legume roots, forming a nitrogen-fixing symbiosis of agricultural importance. In addition, recent studies have shown that rhizobia can colonize roots and aerial plant tissues of rice as a model plant of the Graminaceae family. Here we show that rhizobia can invade tobacco, a model plant belonging to the Solanaceae family. Inoculation of seedling. roots with five GFP-tagged rhizobial species followed by microscopy and viable plating analyses indicated their colonization of the surface and interior of the whole vegetative plant. Blockage of ascending epiphytic migration by coating the hypocotyls with Vaseline showed that the endophytic rhizobia can exit the leaf interior through stomata and colonize the external phyllosphere habitat. These studies indicate rhizobia can colonize both below- and above-ground tissues of tobacco using a dynamic invasion process that involves both epiphytic and endophytic lifestyles.

• Journal of Information Processing Systems
• /
• v.3 no.2
• /
• pp.43-53
• /
• 2007

The use of agent paradigm in today's applications is hampered by the security concerns of agents and hosts alike. The agents require the presence of a secure and trusted execution environment; while hosts aim at preventing the execution of potentially malicious code. In general, hosts support the migration of agents through the provision of an agent server and managing the activities of arriving agents on the host. Numerous studies have been conducted to address the security concerns present in the mobile agent paradigm with a strong focus on the theoretical aspect of the problem. Various proposals in Intrusion Detection Systems aim at securing hosts in traditional client-server execution environments. The use of such proposals to address the security of agent hosts is not desirable since migrating agents typically execute on hosts as a separate thread of the agent server process. Agent servers are open to the execution of virtually any migrating agent; thus the intent or tasks of such agents cannot be known a priori. It is also conceivable that migrating agents may wish to hide their intentions from agent servers. In light of these observations, this work attempts to bridge the gap from theory to practice by analyzing the security mechanisms available in Aglet. We lay the foundation for implementation of application specific protocols dotted with access control, secured communication and ability to detect tampering of agent data. As agents exists in a distributed environment, our proposal also introduces a novel security framework to address the security concerns of hosts through collaboration and pattern matching even in the presence of differing views of the system. The introduced framework has been implemented on the Aglet platform and evaluated in terms of accuracy, false positive, and false negative rates along with its performance strain on the system.

• Journal of Korean Society of Archives and Records Management
• /
• v.16 no.4
• /
• pp.79-120
• /
• 2016

Along with the changing computing environment, the production of public documents is moving to G-Cloud and On-nara System, which are re-engineered on G-Cloud. In this process, it is predicted that the Open Document Format (ODF) will replace the proprietary document format, HWP, and will become widely used in the near future. To preserve digital records produced in ODF, this study reviewed the current long-term preservation strategies and identified considerations for new formats. For ODF source files, it is suggested to eliminate the conversion to PDF/A-1 and preserve the documents in the extended ODF with added metadata of records management. Moreover, ODF is presented as an alternative format for preserving proprietary formats. Finally, this study reviewed the current long-term preservation format, i.e., NEO, and suggests a zipped BagIt package, which has an ISO 21320 specification.

• Korea journal of population studies
• /
• v.18 no.2
• /
• pp.70-97
• /
• 1995

The main purpose of this paper is to analyze the trend of urbanization and population distribution in North Korea. Although North Korean data lack comparable details, attention has been given to the comparison of urban system between North and South Korea. In North Korea, the pace of urbanization was most rapid just after the Korean War, from 1954 to 1960. However, the pace slowed down markedly in the early 1970s and has remained sluggish since then. North Korea is currently much less urbanized than South Korea. As specific features of urbanization in North Korea, emergence of new cities along inland borders, prominence of intermediate-sized cities, and sudden population growth of major cities due to boundary expansion are stressed. Available demographic data also indicate an overwhelming primacy of Pyongyang Municipality in the urban system, and rapid growth of satellite cities in the west-central region. It appears that, in North Korea, urbanization process has been a product of the government's development policies rather than individual's socioeconomic motivation to migrate urbanward. Finally, migration issues after unification of the Korean Peninsula and related problems are discussed in this study.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.30 no.4
• /
• pp.316-322
• /
• 2004

A low molecular weight component named bone morphogenetic protein(BMP) chemically isolated from the organic matrix of bone, induce postfetal connective tissue cells surrounding small blood vessels to differentiate into cartilage and bone. The end product of BMP is a spherical ossicle of lamella bone filled with red bone marrow for the functional loading. This is a important point that the graft material is embedded the defect site during the implant surgery. Because present knowledge of the relationship between BMP and bone regeneration arises mainly from studies of induced bone formation in heterotopic sites, it would be helpful to determine whether BMP plays any part in the process of bone healing. The BMPs have been shown to play crucial roles in normal skeletal development as well as bone healing and are able to activate transcription of genes involved in cellular migration, proliferation, and differentiation. The delivery of BMP on matrices has been efficacious in the treatment of defect bone in implant surgery. The purpose of the histologic study was to evaluate the effect of DLB(demineralized lyophilized bone) coated with purified human BMP(hBMP-I) in immediate implant surgery with bony defect to obtain the functional structure of implant asap. The ability of a graft of hBMP-I to accelerate bony defect repair provides a rationale for its use in immediate implant surgery that have large bone defect in edentulous area.