• Journal of the Korean Geotechnical Society
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• v.40 no.4
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• pp.81-90
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• 2024

With the discovery of energy resources such as water ice on the Moon's surface, the Moon is attracting attention as an outpost for deep space exploration. As the concept of in situ resource utilization (ISRU) for establishing sustainable deep space exploration outposts gains traction, there is an increasing demand for technology to solidify lunar regolith as an in situ resource. In this study, sintered blocks were manufactured using a hybrid microwave sintering furnace. The effects of system configuration and dwell time on the microwave sintering efficiency were assessed. The results indicated that the composition of the SiC susceptor and its distance from the magnetron influenced the manufacturing of homogeneous sintered blocks. Additionally, varying the dwell time at a sintering temperature of 1,080℃ under optimal conditions revealed that exceeding the threshold dwell time caused the sintered blocks to become heterogeneous, thereby reducing the sintering efficiency.

• Geophysics and Geophysical Exploration
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• v.13 no.1
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• pp.51-60
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• 2010

To determine subglacial topography and internal features of the Fourcade Glacier on King George Island in Antarctica, helicopter-borne and ground-towed ground-penetrating radar (GPR) data were recorded along four profiles in November 2006. Signature deconvolution, f-k migration velocity analysis, and finite-difference depth migration applied to the mixed-phase, single-channel, ground-towed data, were effective in increasing vertical resolution, obtaining the velocity function, and yielding clear depth images, respectively. For the helicopter-borne GPR, migration velocities were obtained as root-mean-squared velocities in a two-layer model of air and ice. The radar sections show rugged subglacial topography, englacial sliding surfaces, and localised scattering noise. The maximum depth to the basement is over 79m in the subglacial valley adjacent to the south-eastern slope of the divide ridge between Fourcade and Moczydlowski Glaciers. In the ground-towed profile, we interpret a complicated conduit above possible basal water and other isolated cavities, which are a few metres wide. Near the terminus, the GPR profiles image sliding surfaces, fractures, and faults that will contribute to the tidewater calving mechanism forming icebergs in Potter Cove.

• Journal of Korean Orthopaedic Sports Medicine
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• v.9 no.1
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• pp.7-15
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• 2010

Anterior knee pain syndrome would best be defined as a painful condition that arises in or around the patellofemoral joint and is insidious in onset and bilateral, with an enigmatic entity with multiple causes. Although its etiology is uncertain, the cause is often considered to be abnormal lower limb biomechanics, pathology of extensor mechanism, disorder of patellofemoral joint, malalignment or lateral tracking of the patella, soft tissue tightness, muscle weakness. The measurement of patellar alignment has come to be accepted as an integral part of the examination of anterior knee pain syndrome. Various measurement techniques exist, both clinical and radiological, and these have been frequently used in the diagnosis and treatment of the condition.?Treatment depends on the underlying cause of anterior knee pain and should be directed to the cause rather than to the results. Most often, this involves non-surgical measures, such as anti-inflammatory medications, quadriceps exercises, and hamstring stretching. Shin splint, or medial tibial stress syndrome refers a syndrome of pain running along the inner distal 2/3 of tibia shaft. Shin splint is a common problem for athletes whose sport involves a repeated, jarring impact to the leg. A major factor determining the efficacy of the treatment is that correct diagnosis be made of the problem. The varied etiology has led to the development of several theories as to the cause, treatment, rehabilitation and prevention of shin splint. The management is rest, ice massages, pain relief by medication, and muscle strengthening exercise. Proper rehabilitation and preventative measures can ensure that there is no further recurrence.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.144-152
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• 2018

Lunar exploration, which was led by the United States and the former Soviet Union, ceased in the 1970s. On the other hand, since massive lunar ice deposits and rare resources were found in 1990s, European Union, China, Japan, and India began to participate in lunar exploration to secure future lunar resource as well as to construct a lunar base. In the near future, it is expected that national space agencies and private industries will participate in the lunar exploration together. Their missions will include the exploration and sample return of lunar resources. Lunar resources have a close relationship with the lunar in-situ resource utilization (ISRU). To construct a lunar base, it is inevitable to bring huge amounts of resources from Earth. Water and oxygen, however, will need to be produced from local lunar resources and lunar terrain feature will need to be used to construct the lunar base. Therefore, in this paper, the global trends on lunar exploration and lunar construction technology are investigated and compared along with the ISRU technology to support human exploration and construct a lunar base on the Moon's surface.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.133-137
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• 2011

Winterkill can be defined as any injury including freeze stress kill, winter desiccation, and low temperature disease to turfgrass plants that occurs during the winter period. The major damages from winterkill were low temperature kill, crown hydration, and winter desiccation. Low temperature kill is caused by air and soil temperature. Soil temperature affect more severe to turfgrass than air temperature because low soil temperature cause fetal damage to turfgrass crown. Crown hydration is a form of winter injury in which intercellular water within the plant freezes and causes physical injury to the cell membrane and wall. This is eventually resulted in dehydration of cell. Winter desiccation is the death of leaves or whole plants due to drought during the winter period. To reduce winterkill damage, cultivar selection is very important. If changing cultivar is not allowed, cold temperature hardiness needs to be increased by providing nutrients especially phosphorus and potassium in the late fall. Turf cover is effective way to reduce winterkill damage. Remaining snow is positive process to reduce winterkill damage by insulating soil temperature. The previous researches reported many materials as turf cover such as straw, polypropylene, polyester, and wood mat. Aeration and topdressing is one of the process against winterkill. Both methods are mainly conducted to reduce thickness of thatch layer. In recent, relatively new materials called black or winter topdressing sand are used to protect soil temperature from low air temperature and thaw ice crystal that may remain in soil.

• Solar Energy
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• v.16 no.2
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• pp.113-122
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• 1996

This study presents experimental results of heat transfer characteristics of P.C.M. during outward melting process in a vertical cylinder. The experiment was carried out in six conditions, i. e., three different inlet temperature($7^{\circ}C,\;4^{\circ}C\;and\;1^{\circ}C$) and two directions of working fluid(upward and downward). Melting P.C.M. produced a bell-shaped phase change interface. When the inlet temperature was $7^{\circ}C$, the lower region remained at $4^{\circ}C$ until the temperature of upper region reached $4^{\circ}C$. This was due to the state of maximum density of the lower region. When the direction of the working fluid in the case of $7^{\circ}C$, inlet temperature, was upward, the rate of melting and the total melting energy were higher than when it's direction was downward. But the rate of melting and the total melting energy appeared higher value as it's direction was downward when the inlet temperature is $4^{\circ}C$ and $1^{\circ}C$.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.1
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• pp.23-33
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• 2020

In this study, the effect of surface roughness distribution and its influence on the inflight icing code was investigated. Previous numerical studies focused on the magnitude of surface roughness, and the effects were only addressed in terms of changes in thermal boundary layers with fully turbulent assumption. In addition, the empirical formula was used to take account the turbulent transition due to surface roughness, which was regarded as reducing the accuracy of ice shape prediction. Therefore, in this study, the turbulent transition model based on the two-equation turbulence model was applied to consider the effects of surface roughness. In order to consider the effect of surface roughness, the transport equation for roughness amplification parameter was applied, and the surface roughness distribution model was implemented to consider the physical properties. For validation, the surface roughness, convective heat transfer coefficient, and ice shape were compared with experimental results and other numerical methodology. As a result, it was confirmed that the excessive prediction of the heat transfer coefficient at the leading edge and the ice horn shape at the bottom of the airfoil were improved accordingly.

• Korean Journal of Plant Taxonomy
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• v.36 no.1
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• pp.61-89
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• 2006

Algific talus slopes are local cold micro-environmental habitats where cool air escapes through vents and fissures of talus layer, and ice forms in summer. To access the phytogeographical significance and to develop the conservation strategy on vegetation of the algific talus, plant species composition on seven algific talus in South Korea was investigated. As a results, phytogeographically significant northern elements such as Cystopteris fragilis (L.) Bernh., Diplazium sibiricum (Turcz. ex Kunze) Sa.Kurata, Polypodium virginianum L., Vaccinium vitis-idaea L. and Hackelia deflexa (Wahlenb.) Opiz were distributed in these algific talus slopes (below $N37^{\circ}43^{\prime}$). In addition, subalpine species such as Woodsia subcordata Turcz, Rosa suavis willd., Clematis fusca var. coreana ($H.L{\acute{e}}v.$ & Vaniot) Nakai, Calamagrostis langsdorfii (Link) Trin. and Carex vaginata var. petersii (C.A.Mey.) Akiyama were also distributed as typical relictual species of these algific talus (less than alt. 400m). The algific talus slopes in Korean peninsular can be regarded as the insular refugia that northern plant species advanced southward during the latest glacial age have been isolated and adapted in some local microhabitats. Because the algific talus slopes as paleorefugia are very important in terms of phytogeography as well as meteorology ans geology, developments of strategies for in situ and ex situ conservation on these small isolated and threatened populations associated with the algific talus urgently needed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.630-637
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• 2019

The scientific, economical and industrial values of the Moon have been increased, as massive ice-water and rare resource were founded from the lunar exploration missions. Korea and other major space agencies in the world are competitively developing the ISRU (In Situ Resource Utilization) technology to secure future lunar resource as well as to construct the lunar base. To prepare for the lunar construction, it is essential to develop the rover based construction spatial information technology to provide a decision-making aided information during the lunar construction process. Thus, this research presented the construction spatial information technology based upon rover's camera system. Specifically, the conceptual design of rover based camera system was designed for acquisition of a rover's navigation image, and lunar terrain and construction images around the rover. The reference architecture of the rover operation system was designed for computation of the lunar construction spatial information. Also, rover's localization and terrain reconstruction methods were introduced considering the characteristics of lunar surface environments. It is necessary to test and validate the conceptual design of the construction spatial information technology. Thus, in the future study, the developed rover and rover operation system will be applied to the lunar terrestrial analogue site for further improvements.

• Journal of the Korean Geotechnical Society
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• v.37 no.8
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• pp.51-58
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• 2021

South Korea, as the 10th country to join the Artemis program led by NASA, is actively supporting various researches related to the lunar exploration. In particular, the utilization of water as a resource in the Moon has been focused since it was discovered that ice exists at the lunar pole as a form of frozen soil. Information on the thermal conductivity of lunar regolith can be used to estimate the existence for ice water extraction by thermal mining. In this study, the vacuum pressure effect on thermal conductivity of KLS-1 was investigated with a DTVC (Dusty Thermal Vacuum Chamber). The reliability of KLS-1 was reconfirmed through comparison with thermal conductivity of known standard lunar regolith simulants such as JSC-1A. An empirical equation to assess thermal conductivity considering dry unit weight and vacuum pressure was proposed. The results from this study can be implemented to simulate lunar cryogenic environment using the DTVC.