• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.613-618
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• 2019

The flow-induced vibration in a heat exchanger may cause the damage to piping. Therefore, it is necessary to establish the flow induced vibration characteristics for the structural stability of a heat exchanger. The purpose of this study was to compare the generation, development, and separation characteristics of a vortex around a circular tube with respect to time when the flow velocity of the inlet was fluctuating constantly and periodically. The time characteristics of lift and drag and the PSD characteristics were also investigated. In the case of a constant inlet flow velocity, the well-known Kalman vorticity distribution was shown. The vortex generation, growth, and separation were also observed alternately at the upper and lower sides of the tube. In the case of periodic inlet flow velocity, the vortex occurred simultaneously in the upper and lower sides of the tube. In the case of constant inlet flow velocity, the magnitude of the lift PSD was 500 times larger than that of drag. The frequency was 31.15 Hz and that of drag was doubled at 62.3 Hz. In case of a periodic inlet flow velocity, the PSD of the drag was approximately 500 times larger than that of lift. The frequency was 15.57 Hz, which was the same as the inlet-flow velocity frequency. In addition, the frequency of lift was 31.15 Hz, which was the same Karman vortex frequency.

• Journal of the Korean Applied Science and Technology
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• v.36 no.1
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• pp.248-257
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• 2019

On this study, we have observed the change of the gel nail morphology as the time elapse and measured the surface roughness/volume, moisture content/purcutaneous moisture vaporizing amount of the nail surface before gel nail treatment and after gel nail removing of the 100%acetone remover, 5%acetone remover and 0%acetone remover and the avocado non acetone remover for the comparison of the effect on the nail surface and the degree of the removing of the gel nail of the removers as the acetone contents. The removing ability were the order of 100%acetone remover, avocado non acetone remover, 5%acetone remover and the 0%acetone remover. There were no statistical significance difference in the nail surface roughness comparision before and after gel nail removing in 5%acetone, 0%acetone and avocado non acetone, and there was no statistical significance difference in the nail surface volume comparision before and after gel nail removing in 0%acetone. We measured the moisture content of the nail surface and the purcutaneous moisture vaporizing amount before gel nail treatment and after gel nail removing, resulted that, the decrease of the moisture content of the nail surface after removing the gel nail is the minimun and the increase of the purcutaneous moisture vaporizing amount of the nail surface after removing the gel nail is the minimun at the case of 0%acetone. In conclusion, 5%acetone remover and 0%acetone remover is possible to use as the gel nail remover and they had revealed that there was the least harmful effect on the nail. We hope that this study is utilized to the development of the non acetone remover and the basic research of the nail beauty industry.

• Journal of the Korean Geosynthetics Society
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• v.18 no.1
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• pp.79-89
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• 2019

The field measurement and laboratory experiment were conducted to investigate the effect of reducing the surface temperature of the functional aspect of the heat island phenomenon of the permeable block which is made the recycled synthetic resin rather than the existing concrete permeable block. Field measurement was taken for 3 days in consideration of dry condition and wet condition and laboratory experiment was divided into dry condition, rainfall simulating condition, and wetting condition. The variations of temperature and the evaporation rate of water moisture content after experiment were confirmed. As a result of field measurement, it is confirmed that the surface temperature decreases due to the difference in albedo of the pore block surface rather than the cooling effect due to the latent heat of vaporization. The evaporation of moisture in a dry state where drought persisted or a certain level of moisture was not maintained in the surface layer. As a result of laboratory experiment, resin permeable block gives higher surface temperature when it is dry condition than concrete permeable block, but the evaporation of water in the pore is kept constant by capillary force in rainfall simulation condition, and higher temperature reduction rate. As a result of measuring the evaporation rate after laboratory experiment, it is confirmed that the effect of reducing temperature is increased as the evaporation rate of water is higher. Based on these results, correlation formula for evaporation rate and temperature reduction rate is derived.

• Industry Promotion Research
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• v.4 no.1
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• pp.79-86
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• 2019

The quality of service delivery by governments to their citizens is a subject of concern in the contemporary society. E-governance is a critical aspect that is transforming government operation and service delivery to citizens and other bodies through application of information technology. This research explores the state of e-governing focusing on nations that are developing with special attention to Pakistan. The difficulties and benefits encountered are identified. The results are vital for implementers of e-governing systems in these countries. The methodology applied entails a secondary research that involves analysis and synthesis of literature relating the research topic. The results reveal that Pakistan has made incredible steps in setting up e-governance systems with growth in internet use and access of data from a digital platform. The findings reveal that e-government is associated with multiple benefits including enhanced quality of services, cost efficiency in service provision, enhance transparency and elimination of corruption, provide the basis for eradication of poverty, boost economic stability of a country, and provide room for direct democracy. The research also found that developing countries experience challenges in form of financial constraints, poor ICT infrastructure, illiteracy on e-government, political consensus constraints, legal obstacles, social and cultural constraints. E-government has the capability to transform the quality of governance provided by governments, and policymakers and implementers should address the constraints that act as a hindrance to its implementation.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.1
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• pp.66-73
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• 2019

Approximately 80% of the mines are vacated or abandoned mines and are mostly left without suitable environmental treatment facilities. In the area around the abandoned mine site, problems such as drainage of acidic city drainage and leakage of leachate occur, and ground subsidence caused by this can cause a safety accident due to sink hole occurrence. In this study, flow, compressive strength, water uptake, pore and hydration characteristics were investigated to investigate the basic properties of liner and cover material based on the replacement ratio of nano silica and silica fume in the existing blast - furnace slag fine powder. As a result, as the substitution ratio of nano silica and silica fume increased, the flow and compressive strength of nano silica specimens increased and the absorption rate decreased. In the case of pore characteristics, the amount of pores decreased as the substitution ratio of nano silica and silica fume increased. Especially, the capillary porosity of 10-1,000 nm diameter decreased. Ray diffraction analysis and SEM measurement showed that the peak positions of the hydration products were almost the same when compared with the 5% alternative test samples of Plain and silica fume.

• Journal of the Mineralogical Society of Korea
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• v.32 no.1
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• pp.1-14
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• 2019

This study used microwave-nitric acid leaching with the aim of removing penalty elements such as As and Bi. Moreover, enhanced gold content from the gold concentrate sample. The leaching conditions were changed: leaching time, nitric acid concentrations and solid-liquid ratio; In order to improve the removal of penalty elements. As a result of the experiment; sample weight loss rate, As and Bi removal rate and gold content in the solid-residues have been increased when the nitric acid concentration and leaching time were increased while the solid-liquid ratio was decreased. The leaching conditions for the maximum As and Bi removal and gold content were: leaching with a 6.0 M nitric acid solution doing 5 min. At these, the solid-residue sample weight loss was 87 %. As removal rate was 98.23 % and Bi was completely removed (100 %). Furthermore, gold content increased from 81.36 g/t to 487.32 g/t. The XRD of the solid residue showed that pyrite disappeared as the nitric acid concentration was increased, whereas sulfur peaks was increased, too.

• The Journal of Engineering Geology
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• v.28 no.4
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• pp.645-660
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• 2018

In the southeastern part of the Korean Peninsula, huge fault valleys, including the Yangsan and Ulsan faults, are recognized. These NNE-SSW trending lineaments are called as a whole Yangsan Fault System. However, this fault system is relatively poorly studied except the Yangsan and Ulsan faults. This study deduced the paleostress history based on the mutual cross-cutting relationships between geologic structures developed in the granite body near the Ilgwang fault, which is compared with previous studies. In the study area, four lineaments parallel to the Ilgwang fault are recognized, and three of them show evidences of faulting. In each lineament, both slip-senses of left-lateral and right-lateral are recognized. It indicates that these faults consistently underwent multiple deformations of inversion along the faults. The inferred paleostress directions based on the mutual cross-cutting relationships of the geological structures are as follows: 1) Tensile fractures developed in the late Cretaceous under the ENE-WSW direction of compressive stress, 2) NW-SE trending maximum horizontal principal stress generated conjugate strike-slip faults, and 3) selective reactivations of some structures were derived under the compression by the NE-SW trending principal stress.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.489-496
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• 2019

This paper is a study on the evaluation of loss factor of damping treatment materials to reduce the noise and vibration for panels of railway vehicles and automobiles. In order to determine the modal parameters of damping materials, beam excitation tests were carried out using different type PVC coated aluminum and steel base beam specimens. The specimens were excited from 10 Hz to 1000 Hz frequency range using sinusoidal force, and transfer mobility data were measured by using an accelerometer. The loss factors were determined by using integrated program, based on theories of Half Power Method, Minimum Tangent Error Method, Minimum Angle Error Method and Phase Change Method, which enable to evaluate the parameters using modal circle fit and least squares error method. In the case of lower loss factor and data of linear characteristics, any method could be applied for evaluation of parameters, however the case of higher loss factor or data including non-linear characteristics, the minimum angle error method could reduce the loss factor evaluation. The obtained dynamic properties of the coating material could be used for application of Finite Element Method analyzing the noise control effects of complex structures such as carbody or under-floor boxes of rolling stock. The damping material will be very useful to control the structural noise, because the obtained modal loss factors of each mode show very good effect on over $2^{nd}$ mode frequency range.

• The Korean Journal of Archival Studies
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• no.40
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• pp.95-130
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• 2014

Three frequently used documents by researchers on the Japanese colonial period-Classified Police Records of the Japanese Government-General of korea on the Anti-Japanese Movement 舊 朝鮮總督府 警務局 抗日獨立運 動關係 秘密記錄, Trial Records of Gyeongseong District Court 京城地方法院 裁判記錄 and Filed Documents of Gyeongseong District Court 京城地方法院 編綴文書(while the latter two were collected by the National Institute of Korean History, the former was collected by Asiatic Research Institute of Korea University)-are among the same records group that the Prosecutor's Office of Gyeongseong District Court produced through registration and compilation. As contents related to ideology suppression and thought control were numerous, it could be assumed that most of the materials were produced by the 'Department of Ideology' of the Prosecutor's Office. By examining the administrative records of the 1920's within this group, the process of how the 'Department of Ideology' was formed is clearly shown. As ideological movements for Korea's independence and revolution grew, execution of regulations was further expanded by the Prosecutor's Office. Since the mid-1920's, information on ideology had been separated from general information, was routinely collected heavily, and was considered more valuable than the general information. By the end of the 1920's, the term Ideology Prosecutor 思想係 檢事(meaning a prosecutor who specializes in ideology verification) and the named 'Department of Ideology'(思想部) emerged on the records.

• The Korean Journal of Archival Studies
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• no.30
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• pp.89-123
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• 2011

Archival materials in film archives is a memories and archival documents of human which is generated from cultural activities of human being, and provided long-term relevant information. However, it is different general public audio-visual records because main purpose of representing culture to create the contents of private sector rather than evidence of the factual information of public service activities. Therefore, should determine the description principle and rule in order to reflect specific physical, intellectual characteristics. So as to control the description, that is need in the textual standards to base the specific purposes and rules thus analyzed the international description standards as Dublin Core, ISAD(G), FIAF Cataloguing Rules For Film Archives. As a result, more effectively to describe archival materials in film archives required significant modifications in the organizations of the areas and the elements. This study argues that first, to divide existence the concept and the reality (work/item) of archival materials in film archives. Second, to need understanding and indicating their content, context, structure. Third, to establish of the areas and the elements including a characteristic of it. The final suggestion organizes separately to 6th and 8th areas, 22th and 25th elements in two parts. This conclusion does not prepare to refer the status and/or policy of a particular film arhicve, can be set accordingly to a specific elements or sub-elements by the film archives.