• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1181-1187
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• 2012

For the fatigue design of aircraft landing gear, the safe-life approach is applied. Structural defects such as cracks or detrimental deformations should not occur under the fatigue load spectrum depicting the entire lifetime usage of the aircraft. In the design phase, the fatigue life of the landing gear is estimated analytically by adopting the stress-based approach because the fatigue of aircraft landing gear is generally high-cycle fatigue. This utilizes S-N curves that are factored to produce design curves that account for the scatter and surface finish of the material. In the test and evaluation phases, a fatigue test should be conducted for full-scale landing gear to substantiate the fatigue design requirement in the end. In this study, the procedure for the fatigue test and evaluation of aircraft landing gear is presented with real application cases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5721-5727
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• 2015

Paint must be resistant to the wear and tear of the atmosphere and should maintain its color and finish for a long time. The solvents of paints were organic solvent and water, common artificial source of VOCs(Volatile organic Solvent) include organic solvent. Using of organic solvent paint was decreased in the interior parts of automotive, exterior parts were still used organic solvent paint. Adhesive strength of water-paint was poor to compare with organic solvent paint and peeled off from the base materials, it was big quality problem. In this study, adhesive characteristics of water-paint and silane mixture was investigated. To improve adhesive strength of water-paint, it was necessary to mixing of adhesive material. Adhesive strength was measured using UTM(Universal Test Instrument) by ASTM D1002 and Peeling off condition was by ASTM D3359. Optimal mixing condition of water-paint and silane adhesive were $25^{\circ}C$, 500rpm, 20min., concentration of silane adhesive was 5 wt%.

• Journal of the Society of Disaster Information
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• v.10 no.1
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• pp.91-97
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• 2014

purpose of this study was to conduct status survey on existing shelter facilities for residents and use it as basic material to plan and design improved shelter facilities in the future. As the result, first, although existing shelter facilities are judged to have been designed in consideration only of the protection from high explosive shells, actual protection capability is significantly low against high explosive shells when exit direction and protection capabilities of main entrances were investigated. Second, all the 7 facilities did not have air purifier with filters installed for the air that flows into the inside from outside and since the height of air exhausts and intake pipes in the outside are also close to the earth, there are possibilities that heavy contaminated air can flow into the inside. Third, although some facilities have anti-explosion doors installed, it is impossible to use them as chemical, biological and radiological (CBR) shelter because of improper installation of openings and anti-explosion valves as well as poor plumbing that cannot ensure air-tightness and poor finish of piping penetration.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.865-868
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• 2008

As a part of a series of study, this study reviewed the fire proof characteristics of high performance concrete RC column members using non-stripping form that accompanied metal lath lateral confinement to prevent spalling of high performance concrete which is increasingly used recently, and the results are as follows. Flow and air amount both satisfied target range, and compressive strength, over 80MPa at age 28 days, showed high strength range. As for spalling characteristics, in the case of plain in which no fiber is mixed, severe spalling occurred, and in the case of 0.05% nylon("NY" hereinafter)+polypropylene("PP" hereinafter) fiber mixture, only surface area experienced partial spalling. Regarding non-stripping form changes, both non-stripping 25-20 and non-stripping 50-20 experienced spalling at finish material area, and non-stripping 50-20 showed better spalling proof performance than non-stripping 25-20. In the case of non-stripping 50-40, spalling was prevented, and while mass reduction rate was less than 10%, its temperature hysteresis showed the most excellent fire proof performance with base metal surface area maximum temperature $376.1^{\circ}C$.

• Korean Journal of Oriental Medicine
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• v.15 no.2
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• pp.85-91
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• 2009

The manufacture date of the number 198 wooden tablet excavated at Anapji is estimated to be between year 751 and 774. As medical artifacts around this period of time is scarce, the discovery of an artifact with distinct medical information such as names of medicinal drugs recorded in hand writing holds great value in the history of medicine. This wooden tablet was presumably a prescription for a medicinal formula. That the '灸' character which is a method of processing drugs is found after '甘草' indicates the possibility of this wooden tablet to be a practical form of prescription. On this slip, a certain sign can be found at the upper right corner of the names of drugs. This is thought to be an additional sign added to the original text. It seems to have been originated from the letter '了', based on the composition and finishing touches of the strokes, presumably to confirm the end of a work by adding the letter '了' which means 'to finish'. The base material of 靑黛 and 藍淀 are the same, and the two often took each other's place in a prescription. It is difficult to find an example of a formula where both drugs are included. Therefore, the prescription on the front with 靑黛, and the one on the back with 藍淀 of tablet 198 can be understood as separate formulas.

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.245-252
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• 2003

There have been many kinds of hair styling sprays with various setting effects. Consumers have used strong setting effect hair sprays to get a long lasting hold. In recent years, however, more and more consumers have come to prefer a "soft ＆ natural" touch feeling, keeping the same long lasting hold. Nonetheless, the existing approaches to this feature could not respond to the consumers′ needs, since products lose the hold strength if the soft feeling is pursued, and vice versa. We have researched and developed a new products to attain a compatible feature with both long lasting hold and natural feeling. Then, we have developed a new multifunctional hair styling material "Poly Amino Acid Derivative (PAAD)." We have focused on the PAAD′s feature that highly diffuses onto a hair and makes thin and even layer on a hair, and have made trials and errors to improve holding strength. "P AAD" excellently makes hair memorize its curl shape which is as the same effect as existing ordinary acrylic resin. Further more, it leaves a soft and natural touch feeling on the hair. We have accomplished a new Poly Amino Acid Derivative with ambivalent features, "soft ＆ natural finish" and "long lasting hold ", and now we report about it.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.1
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• pp.85-102
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• 2006

Statement of problem: Currently, there are some 20 different geometric variations in implant/abutment interface available. The geometry is important because it is one of the primary determinants of joint strength, joint stability, locational and rotational stability. Purpose: As the effects of the various implant-abutment connections and the prosthesis height variation on stress distribution are not yet examined this study is to focus on the different types of implant-abutment connection and the prosthesis height using three dimensional finite element analysis. Material and method. The models were constructed with ITI, 3i TG, Bicon, Frialit-2 fixtures and solid abutment, TG post, Bicon post, EstheticBase abutment respectively. And the super structures were constructed as mandibular second premolar shapes with 8.5 mm, 11 mm, 13.5 mm of crown height. In each model, 244 N of vertical load and 244 N of $30^{\circ}$ oblique load were placed on the central pit of an occlusal surface. von Mises stresses were recorded and compared in the crowns, abutments, fixtures. Results: 1. Under the oblique loading, von Mises stresses were larger in the crown, abutment, fixture compared to the vertical loading condition. 2. The stresses were increased proportionally to the crown height under oblique loading but showed little differences with three different crown heights under vertical loading. 3. In the crown, the highest stress areas were loading points under vertical loading, and the finish lines under oblique loading. 4. Under the oblique loading, the higher stresses were located in the fixture/abutment interface of the Bicon and Frialit-2 systems compared to the ITI and TG systems. Conclusions: The stress distribution patterns of each implant-abutment system had difference among them and adequate crown height/implant ratio was important to reduce the stresses around the implants.

• Journal of the Korea Institute of Building Construction
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• v.21 no.6
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• pp.573-581
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• 2021

In this study, a basic experiment was conducted to examine the possibility of using mechanochromic sensors to monitor the health of construction structures. The strain and color variation characteristics of the mechanochromic sensor according to the type of finish of the concrete material were investigated. As a result, it was confirmed that the strain and color variation reactivity of the mechanochromic sensor increased as the tensile strain of the concrete specimen increased. In addition, the difference in the finishing environments of concrete, urethane, epoxy, water-based paint and oil-based paint did not affect the deformation and discoloration characteristics of the mechanochromic sensor.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.14-15
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• 2020

The need for off-site construction has increased in the construction industry in Korea in recent years due to the enforcement of the 52-hour workweek, the increasing age of workers on construction sites, the deepening dependence on overseas workers, and the stagnation of productivity in the construction industry. Thus, studies on OSC started in April 2020. In addition, as a national policy study advocating the modular construction method, which is one of the OSC methods, was completed in the first half of 2019. 70 housing units in two complexes that satisfied the Housing Act requirements have been supplied to citizens. However, although modular construction methods have been recognized as a dramatic construction method that achieves shortened construction schedules and solves the issues of cost reduction and the shortage of technical workers on sites by combining the advantages of the manufacturing industry and applying the economies of scale, realistically it has issues due to the rising cost of steel and a low pre-fabrication ratio. Moreover, the construction time of core parts, such as those built by pouring concrete, has become a factor that hinders the shortening of construction times. Thus, this study aims to propose a precast concrete(PC) modular construction system, which fuses three-dimensional infill as an interior finish material and a three-surface PC module that can acts as a structure for a construction method that is economical and can shorten construction time.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.5
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• pp.114-122
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• 2007

In high strength bolted joints, the corrosion of base material causes the reduction of slip resistance of the joints. In this study, tensile tests on slip-critical joints utilizing Zn/Al metal spraying corrosion resistance method were carried out in order to prevent the corrosion and meet the required mechanical characteristics of joints. In addition, slip coefficient and surface roughness were calculated. The key parameters were surface finishing condition and thickness of coating with the identical geometry in all specimens. From the results, it is found that the slip coefficient of the joints with coated finish after sand blast treatment as well as those of non-coated joints with only sand blast treatment were similar or superior to 0.45, which is a specification criteria of slip coefficient in friction-typed joints.