• Advances in concrete construction
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• v.10 no.5
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• pp.443-454
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• 2020

In recent years, many studies have been done on the performance of concrete containing glass powder (GP). For the purpose of widespread use of GP in concrete mixes, a knowledge of the performance of such a mixture after a fire is essential for the perspective of structural use. This research work was carried out to evaluate the performance of High Performance Concrete (HPC) made with GP after being exposed to elevated temperature. The studied mixtures include partial replacement of cement by GP with up to 30%. The mechanical performance and structural alterations were assessed after high temperature treatment from 200℃ to 800℃. The mechanical performance was evaluated by testing the specimens to the compressive and tensile strength. In addition, the mass loss and the porosity were measured to notice the structural alterations. Changes in microstructure due to temperature was also investigated by the X-ray diffraction (XRD) and thermal gravimetric analyses (TGA) as well as porosity adsorption tests. The results of the concrete strength tests showed a slight difference in compressive strength and the same tensile strength performance when replacing a part of the cement by GP. However, after high temperature exposition, concrete with GP showed better performance than the reference concrete for temperature below 600℃. But, after heating at 800℃, the strength of the concrete with GP drop slightly more than reference concrete. This is accompanied by an important increase in mass loss and water porosity. After the microstructure analysis, no important changes happened differently for concrete with GP at high temperature except a new calcium silica form appears after the 800℃ heating.

• Journal of the Korean Wood Science and Technology
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• v.33 no.4 s.132
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• pp.15-22
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• 2005

The acoustic properties of various coatings for stringed musical instruments made were investigated. The applied coatings were urethane topcoat, oil stain, natural varnish, cashew and UV-curable epoxy coating. Acoustic properties of coatings inferred from a resonance frequency and a damping measured by FFT analyzer and tan ${\delta}$ measured by DMTA. Acoustic properties from resonance frequency and damping were analyzed. Optimum coating for stringed instruments was determined by viscoelastic properties and acoustic properties of coating.

• The Journal of the Korea Contents Association
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• v.16 no.7
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• pp.168-178
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• 2016

The purpose of the study is to present an analysis of the expatriate leasing market for highly-paid professionals residing in Seoul. The effects of physical and locational attributes, range of amenities along with expat's national and industrial attributes on housing rents are being empirically evaluated based on transactions. Using lease transaction data for the period of 1994 through 2013, the results show that physical and locational attributes which have been proved to affect conventional housing value are also confirmed to affect leasing housing rent for expatriate. Also this study finds the following results. First, housing rent is found to be influenced by foreign residents' occupation. Therefore banking, petrochemical, insurer and pharmaceutical company affect positively on housing rent while mechanic firms influenced negatively to rent. Second, housing rent is found to be affected by foreign residents' nationalities. The results indicate USA and the United Kingdom have a positive effect while French has a negative effect on rent.

• The korean journal of orthodontics
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• v.26 no.1 s.54
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• pp.113-124
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• 1996

The purpose of this report is to present the successful improvement of occlusal relationship and facial estherics in Class II div.1 malocclusion by orthodontic treatment with upper first premolars and lower second premolars extracted. Before treatment, the patients showed Class II div. 1 relation with severe overjet. deep overbite, large ANB angle, retrusive mandible and a convex soft tissue profile. After treatment, normal canine and molar relationships were obtained. Facial esthetics were improved. There were no mesial tipping of lower first molars and root resorptions. With the adequate diagnosis and treatment plan and biomechanics, the application of upper first and lower second premolar extraction may be one of good strategies in some Class II cases treatment.

• The korean journal of orthodontics
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• v.28 no.6 s.71
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• pp.991-999
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• 1998

Tooth impaction may lead to malocclusion, root resolution, cyst or aberrant changes in adjacent teeth. Clinical and radiographic examinations are used to locate the impaction, and appropriate treatment plans must be made to relocate the impacted tooth. When surgically exposing the impacted tooth, periodontal considerations to conserve maximum amount of soft and hard tissue are used. Oral hygiene instructions are emphasized to maintain sound periodontal health. Securing enough space for the impacted tooth and proper anchorage is important. Proper use of force and mechanics is crucial to prevent such complications as root resolution. Various patterns of orthodontic traction may be employed as situation permits. Most impaction cases can be managed with orthodontic traction to restore function and esthetics, provided that early detection and proper diagnosis and treatment planning are made.

• Journal of the Korean Society for information Management
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• v.18 no.2
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• pp.125-142
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• 2001

This study attempts to identify users' potential information needs in a medium-sized academic library by analyzing reference questions raised by library users for 64 days from October 10th to December 13th, 2000. A total of 474 reference questions were analysed of which only 10.1% were pure reference questions that dealt with the professional knowledge of reference librarians. 71.0% had nothing to do with professional knowledge, being directional(29.3%), mechanic(23.8%), and library policy related(l7.9%). Improvements in sign system and guiding materials in the library should be made to deliver reference services of good quality to academic library users.

• Korean journal of food and cookery science
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• v.21 no.4 s.88
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• pp.422-432
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• 2005

Shinuncho(Angelica keiskei koidz)sulgi is a kind of steamed rice cake by an earthenware steamer. I made Shinuncho-sulgi samples with different amounts of Angelica keiskei koidz - powder and different types of sugars (sugar or honey). The more Angelica keiskei koidz powder it has the bitter it tastes but the lower sweetness, moistness and chewiness it has. Samples with honey have higher sweetness, moistness and chewiness but lower bitterness and after-swallowing than ones with sugar. Color is Shinsuncho-sulgi with $3\%$ of Angelica keiskei koidz - powder and honey has been judged to have the best quality. Flavor and Overall-acceptability are Shinsuncho-sulgi with $2\%$ of Amge;oca keiskei koidz - powder and honey has been judged to have the best quality. The more Angelica keiskei koidz powder it has the higher hardness but the significantly cohesiveness, springiness, gumminess, and chewiness it has. Samples with honey have higher hardness, springiness, cohesiveness, gumminess and chewiness, but lower adhesiveness, than ones with sugar. The moisture content of Shinsuncho-sulgi is $35.89\~37.08\%$. Samples with honey have higher b-value but lower L-value and a-value than ones with sugar. Based on the results of the study, the best ratio of ingredients is as follow non-glutinous flour 196g, Angelica keiskei koidz powder $2\%$ (4g), honey 35ml, salt 2g, water 20ml and $37.08\%$ of moisture content.

• Archives of Plastic Surgery
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• v.35 no.4
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• pp.455-460
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• 2008

Purpose: We have classified blepharoptosis into the categories including pseudoptosis in Koreans and compared with other previous studies. Methods: Total of 250 patients(398 eyes) who underwent surgery for blepharoptosis from 1987 to 2006 were studied. By classification of Beard, patients were categorized into congenital, acquired and pseudo blepharoptosis and later they were reclassified by their etiologies. Also addition of pseudoptosis to the classification of Frueh, blepharoptosis were categorized into neurogenic type, myogenic type, aponeurotic type, mechanical type and pseudoptosis. And we divided these cases by the degree of blepharoptosis, levator function and the operation methods. Results: Out of the 250 patients, 175 patients were congenital type, 49 were acquired type and 26 were pseudoptosis. According to the mechanistic classification, 177 myogenic type, 30 aponeurotic, 7 mechanic, 8 neurogenic and 28 pseudoptosis were categorized. Regarding severity of blepharoptosis, there were 29.2% of mild, 40% of moderate, and 30.8% of severe cases. Out of the 398 cases, in terms of the operation methods, there were 39 aponeurosis plication, 184 levator resection, 5 Muller tucking, 60 Orbicularis oculi muscle flap, 66 frontalis transfer, and 21 blepharoplasty. Conclusion: The cause and degree of ptosis, and levator function are very important when considering the amount of resected muscle. There were only a few studies about blepharoptosis classification including pseudoptosis category. Therefore, through this study, we can investigate the relationship between the pseudoptosis and the others. This study could be useful for the making future management plans of blepharoptosis in Korean patients.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.10 s.175
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• pp.114-120
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• 2005

Urethane is a high polymeric and elastic material useful in designing mechanic parts that cannot be molded with rubber or plastic material. In particular, urethane is high in mechanical strength and anti-abrasive. Hereby, a urethane coated aluminum wheel is used to support of the OHT vehicle moving back and forth to transport products. For the sake of verifying the safety of the vehicle, structural safety fur applied maximum dynamic load on a urethane wheel must be examined carefully while driving. Therefore, we performed a dynamic simulation on the OHT vehicle model and we determined the driving load. The area definition of applied load may be obtained from the previous study of Hertzian and Non-Hertzian contact force model having exact properties of contact material. But the static analysis is simulated after we have performed the actual contact area test for each load since the proper material properties of urethane have not been guaranteed. In this study, the method of distributing loads for each node is included. Finally, in coMParison with the results of analysis and load-displacement curve obtained from the compression test, we have defined the material properties of urethane. In the analysis, we verified the safety of the wheel. Finally, we performed a mode analysis using the obtained material properties. With these results, we presented a reliable finite element model.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.2
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• pp.158-163
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• 2003

Thermosetting matrix composites have disadvantages in terms of moulding time, repairability and manufacturing cost. Thus the high-performance thermoplastic composites to eliminate such disadvantages have been developed so far. As a result of environmental and economical concerns, there is a growing interest in the use of thermoplastic composites. However, since their mechanical properties are very sensitive to the environment such as moisture, temperature etc., those behaviors need to be studied. Particularly the temperature is a very important factor influencing the mechanical behavior of thermoplastic composites. The effect of temperature have not yet been fully quantified. Since engineering applications of reinforced composites necessitate their fracture mechanic characterization, work is in progress to investigate the fracture and related failure behavior. An approach which predicts the tensile strength was perpormed in the tensile test. The main goal of this work is to study the effect of temperature on the result of tensile test with respect to GF/PE composite. The tensile strength and failure mechanisms of GF/PE composites were investigated in the temperature range 6$0^{\circ}C$ to -5$0^{\circ}C$. The tensile strength increased as the fiber volume fraction ratio increased. The tensile strength showed the maximum at -5$0^{\circ}C$, and it tended to decrease as the temperature increased from -5$0^{\circ}C$. The major failure mechanism was classified into the fiber matrix debonding, the fiber pull-out, the delamination and the matrix deformation.