• Geomechanics and Engineering
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• v.13 no.1
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• pp.1-23
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• 2017

A coupled liquid-gas-solid three-phase model, linking two numerical codes (TOUGH2/EOS3 and $FLAC^{3D}$), was firstly established and validated by simulating an in-situ air flow test in Essen. Then the coupled model was employed to investigate responses of multiphase flow and soil skeleton deformation to compressed air or freshwater injection using the same simulation conditions in an aquifer of Tianjin, China. The simulation results show that with injecting pressurized fluids, the vertical effective stress in some area decreases owing to the pore pressure increasing, an expansion of soil skeleton appears, and land uplift occurs due to support actions from lower deformed soils. After fluids injection stops, soil deformation decreases overall due to injecting fluids dissipating. With the same applied pressure, changes in multiphase flow and geo-mechanical deformation caused by compressed air injection are relatively greater than those by freshwater injection. Furthermore, the expansion of soil skeleton induced by compressed air injection transfers upward and laterally continuously with time, while during and after freshwater injection, this expansion reaches rapidly a quasi-steady state. These differences induced by two fluids injection are mainly because air could spread upward and laterally easily for its lower density and phase state transition appears for compressed air injection.

• Korean Journal of Materials Research
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• v.31 no.8
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• pp.458-464
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• 2021

Tungsten disulfide (WS₂), a typical 2D layerd structure, has received much attention as a pseudocapacitive material because of its high theoretical specific capacity and excellent ion diffusion kinetics. However, WS₂ has critical limits such as poor long-term cycling stability owing to its large volume expansion during cycling and low electrical conductivity. Therefore, to increase the high-rate performance and cycling stability for pseudocapacitors, well-dispersed WS₂ nanoparticles embedded in carbon nanofibers (WS₂-CNFs), including mesopores and S-doping, are prepared by hydrothermal synthesis and sulfurizaiton. These unique nanocomposite electrodes exhibit a high specific capacity (159.6 F g^-1 at 10 mV s^-1), excellent high-rate performance (81.3 F g^-1 at 300 mV s^-1), and long-term cycling stability (55.9 % after 1,000 cycles at 100 mV s^-1). The increased specific capacity is attributed to well-dispersed WS₂ nanoparticles embedded in CNFs that the enlarge active area; the increased high-rate performance is contributed by reduced ion diffusion pathway due to mesoporous CNFs and improved electrical conductivity due to S-doped CNFs; the long-term cycling stability is attributed to the CNFs matrix including WS₂ nanoparticles, which effectively prevent large volume expansion.

• Korean Institute of Interior Design Journal
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• v.19 no.3
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• pp.22-29
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• 2010

Recent days, transition to ecological thought is being accelerating by environmental impact with a sustainable development. This symptom is no exception in architecture area. So is vernacular design affecting on modern architecture in many ways in terms of economical aspect and eco-friendly environment as well. Natural energy like solar power, environment, and terrestrial heat that applied in vernacular architecture is also widely accepted in name of 'sustainable energy' of which a design applied with ventilation and airing of natural wind is very useful & pragmatic in terms of economical reason. Accordingly, this study examined a relation between vernacular architecture and natural wind and compared it with traditional type and its feature of ventilation & airing. Ventilation & airing applied in the past can be divided into three categories: methods by convection, natural element, and architectural type. All these methods gave some pleasant felling indoors when there were no artificial energies. Even in modern age, such a ventilation & airing is being used with traditional type in different variety of materials, and it will be developed with modern technology without any extra cost in terms of sustainable expansion, and opened for further researches.

• Advances in aircraft and spacecraft science
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• v.5 no.3
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• pp.295-318
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• 2018

This research studies thermo-elastic behavior of rotating micro discs that are employed in various micro devices such as micro gas turbines. It is assumed that material is functionally graded with a variable profile thickness, density, shear modulus and thermal expansion in terms of radius of micro disc and as a power law function. Boundary condition is considered fixed-free with uniform thermal loading and elastic field is symmetric. Using incompressible material's constitutive equation, we extract governing differential equation of four orders; to solution this equation, we utilize general differential quadrature (GDQ) method and the results are schematically pictured. The obtained result in a particular case is compared with another work and coincidence of results is shown. We will find out that surface effect tends to split micro disc's area to compressive and tensile while nonlocal parameter tries to converge different behaviors with each other; this convergence feature make FGIMs capable to resist in high temperature and so in terms of thermo-elastic behavior we can suggest, using FGIMs in micro devices such as micro turbines (under glass transition temperature).

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.10
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• pp.844-854
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• 2017

The Expansion-Deflection(E-D) nozzle is a nozzle that has a performance gain through the altitude compensation effect by changing the effective area within the nozzle according to the altitude. An E-D nozzle has been known to reduce the length of the nozzle and achieve the payload gain of the launch vehicle. Due to the potential advantages of an E-D nozzle, related research has been carried out in the United Kingdom, Germany, Australia and Europe etc. In the UK, the flow characteristics of the E-D nozzle and the performance comparison with the dual-bell nozzle which is altitude compensation nozzle were studied. In order to understand the transition characteristics of the E-D nozzle in DLR, the transition characteristics according to the nozzle pressure ratio change were analyzed. In Europe, numerical study using the E-D nozzle concept on upper stage of the launch vehicle Ariane 5 ESC-B was carried out to confirm the possibility of payload gain according to the nozzle length reduction. In this paper, research trends of an E-D nozzle performed outside the country are classified and analyzed according to their characteristics and utilized as basic data of E-D nozzle research in the future.

• Convergence Security Journal
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• v.21 no.1
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• pp.137-147
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• 2021

The purpose of this study is to summarize the variables for making the power expansion of terrorist organizations possible by analyzing the power transitions among the Somalia governments and terrorisms. For this, I created a framework after extracting the independent variables affecting the power transition using the theories of Hans J. Morgenthau, A.F.K Organski, K.J. Holsti. On the basis of these, I analyzed the power transitions among the organizations from August 2012(the foundation of Federal government) to August 2019. According to the results, the power area of the federal government is extremely narrowed, whereas the power areas of al-Shabaab, ISIS, and neutral conflict are largely expanded. The factors in the framework were embodied as the delay of powerful federal government foundation, the shortage of national military forces, the limitation of effective use of foreign forces, the continuation of cooperation and antagonism among armed terrorist organization, sanctuary environment of terrorists using the Sharia law, advantages of force recruitment resulted from the bad economic conditions, public support suitable for the Somalia environment. All of these factors work the causes of lasting anarchy condition of the federal government of Somalia by making the settlement of conflict against terrorist organizations.

• Economic and Environmental Geology
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• v.45 no.2
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• pp.79-88
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• 2012

The increased brightness and focused X-ray beams now available from laboratory X-ray sources facilitates a variety of powder diffraction experiments not practical using conventional in-house sources. Furthermore, the increased availability of 2-dimensional area detectors, along with implementation of improved software and customized sample environmental cells, makes possible new classes of in-situ and time-resolved diffraction experiments. These include phase transitions under variable pressure- and temperature conditions and ion-exchange reactions. Examples of in-situ and time-resolved studies which are presented here include: (1) time-resolved data to evaluate the kinetics and mechanism of ion exchange in mineral natrolite; (2) in-situ dehydration and thermal expansion behaviors of ion-exchanged natrolite; and (3) observations of the phases forming under controlled hydrostatic pressure conditions in ion-exchanged natrolite. Both the quantity and quality of the in-situ diffraction data are such to allow evaluation of the reaction pathway and Rietveld analysis on selected dataset. These laboratory-based in-situ studies will increase the predictability of the follow-up experiments at more specialized beamlines at the synchrotron.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.5
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• pp.442-448
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• 2007

The ultrasonic inspection system for the expansion/transition area of steam generator tube was successfully developed. Variety of artificial flaw and real track specimen was tested using the UT system to verify the performance of the system. All artificial flaws of which through-wall depth larger than 10% was clearly detected by UT system. Measurement results of through-wall depth of flaws larger than 20% had good linearity and reproducibility with 3.27 of standard deviation. Results of real crack specimen test suggested that the detection limit of real crack strongly depends on the track morphology. A potential for measurement of PRL(percentage of remaining ligament) was recognized by the real crack specimen test.

• Journal of the Economic Geographical Society of Korea
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• v.23 no.3
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• pp.229-246
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• 2020

The global environment is rapidly changing due to the Coronavirus outbreak, especially in areas that have been relatively neglected, such as border areas. In particular, In the post-COVID era, the border area between the two Koreas requires a new perception and conceptualization as a space for reconciliation, cooperation and coexistence. Through the status and outlook of post-COVID era, this paper analyzed the promoting directions of each situation, such as SWOT analysis, depending on the characteristics of changes such as domestic preference, changes into standards of new national competitiveness, changes into regional value chains, and the transition to digital economy in the era of the Fourth Industrial Revolution. Based on the previous analysis, this paper proposed realistic approaches such as the utilization of buffer zones, expansion of non-political cooperation to prepare resilience, and promotion of new growth engine industries. In addition, this paper suggested prepared strategies for analyzing the influence of positive and negative cases and responding to them by writing possible scenarios.

• Korean Institute of Interior Design Journal
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• v.18 no.4
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• pp.124-131
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• 2009

The aesthetics of current dermatology clinics are the main space of dermatology, which is gradually becoming an area of specialty. Paths requiring spatial transition due to the expansion of treatment field in dermatology clinics are currently emerging, meaning that the duty to provide medical and aesthetic environment with high spatial connection must be accompanied. Contrary to past clinics where only functional aspects were emphasized, current clinics require a differentiated environment that considers both aspects of function and aesthetics, centered on the patient. The purpose of this research in this perspective is to study the efficient connection between dermatology and aesthetics, while also analyzing identity factors to indicate design factors differentiated from other functional spaces, to apply them as preliminary data for the planning of dermatology clinics. Based on the above, six dermatology clinics located in Seoul were designated for case studies through field studies. Overall, Aesthetics connected to dermatology clinics legally must have separate business registrations and have alternative entrance ways. Currently however, there were many cases where entrance, waiting, reception and receipt were not separated. there were efforts to partially display identities when analyzing design factors that formed the identity of dermatology clinics. However, there were insufficient cases where visual communication factors such as a clinic's spatial identity, logo, signing system, and applied products were integrated into a coherent theme. At this point when dermatology clinics are becoming brands, all fields must merge for integrated identity effects that go beyond the boundaries of contemporary H.I, to clearly display their identity with the clinics' professional image and consistent concept.