• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.5
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• pp.82-86
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• 2013

The automotive weather strip has the functions isolating of dust, water, noise and vibration from outside. The core of weather strip is made of steel with stiffness. By using the wire formed as the core of weather strip, weight can be reduced as much as 35% by comparing with existing steel core. For this reason, forming wire is necessary to keep the zigzag shape as it is. The deformation which is occurred during forming process can be predicted and it can be used in case of manufacturing dies through CAE. In this paper, rolling process conditions are deduced and the springback amount is predicted after rolling process by using the simulation. The springback amount of product is measured by using optical microscope, and measurement result is compared with the simulation result of springback as the same condition. The suitable gap between dies to compensate springback after rolling process is predicted through simulation and it is used for manufacturing dies.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.3
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• pp.338-350
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• 1996

A numerical analysis is carried out to study the two-dimensional steady state natural convection from vertical wires immersed in cold pure water. The surface of the wire is $0^{\circ}C$ unifrom temperature. Results of the analysis are presented for free stream temperature from $0^{\circ}C$ to $25^{\circ}C$ and the aspect ratio N from $5.26{\times}10^{-3}$ to $1.0{\times}10^{-3}$. The effects of the density extremum and aspect ratio on the flow pattern and the heat transfer characteristics are discussed As the aspect ratio N becomes larger, in the range of $1.0^{\circ}C{\leq}T_{\infty}{\leq}4.4^{\circ}C$ and $6{^{\circ}C}{\leq}T_{\infty}{\leq}17^{\circ}C$, the effect of Pr number on the heat transfer is shown to be more significant than the aspect ratio. Investigating into the effect of the density extremum on the heat transfer from wires, the new heat transfer correlations are suggested with the relation of average Nu mumber vs. modified Ra number. Here, the coefficient values C of correlations are presented as the function of density extremum parameter $R^*$. The effects of the density extremum parameter are also discussed.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.4
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• pp.505-513
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• 2022

Minor orthodontic treatment using a thin wire with high elasticity can shorten the treatment period and reduce the load on the anchorage by the application of light force. Since it can be applied immediately without a dental laboratory procedure and does not require the patient's cooperation, it can be clinically useful. The cases reported here have led to positive results in short periods of treatment, using only a segmented straight 0.012 inch NiTi wire and flowable resin to address various locations within the oral cavity, such as the anterior teeth, premolars, and molars.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.7
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• pp.743-749
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• 2014

In this study, a noncircular drawing (NCD) sequence for manufacturing high-strength and high-ductility pearlitic steel wires was investigated. Multipass NCD was conducted up to the 12th pass at room temperature with two processing routes (defined as the NCDA and NCDB), and compared with the wire drawing (WD). During the torsion test, delamination fracture in the drawn wire was observed in the 10th pass of the WD whereas it was not observed until the 12th pass of the NCDB. From X-ray diffraction, the circular texture component that increases the likelihood of delamination fracture of the drawn wire was rarely observed in the NCDB. Thus, the improved ability of the multipass NCDB to manufacture high-strength pearlitic steel wires with high torsional ductility compared to the WD (by reducing the likelihood of delamination fracture) was demonstrated.

• The korean journal of orthodontics
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• v.37 no.5
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• pp.376-385
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• 2007

Esthetic brackets which resemble the color of natural teeth have been widely used. But the frictional resistance of ceramic brackets, a typical esthetic bracket, is greater than that of metal brackets. The purpose of this study was to measure the frictional resistance of the new calcium phosphate brackets (CPB) which were recently developed and to evaluate its clinical usability by comparing the frictional differences of CPB with metal brackets and metal slot inserted ceramic brackets. Methods: Experimental groups were CPB (Hyaline II, Tomy, Tokyo, Japan), metal bracket (Kosaka, Tomy, Tokyo, Japan) and metal slot inserted ceramic bracket (Clarity, 3M Unitek, Monrovia, CA, USA). All of the brackets had 0.022-inch slot sizes. The brackets were tested with $0.019\;{\times}\;0.025$ inch stainless steel wire (3M Unitek, Monrovia, CA, USA). A biologic model was used to simulate the situation which would occur during orthodontic treatment with fixed appliances. Retraction force was applied at a speed of 5 mm/min for 30 seconds. The frictional resistance was measured on a universal testing machine (Instron 4467, Instron, Norwood, MA, USA). Results: CPB showed significantly higher friction than metal brackets (p < 0.05) and lower friction than metal slot inserted ceramic brackets (p < 0.01). Conclusions: CPB can be considered to be a useful orthodontic esthetic bracket with respect to frictional resistance, as its friction is remarkably lower than that of metal slot inserted ceramic brackets.

• Journal of Korean Society of Forest Science
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• v.82 no.2
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• pp.195-206
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• 1993

The purpose of this study is to provide a basis for establishing regional harvesting systems that ist the prerequisites for the forest mechanization. The factors restricting to the forest harvesting and logging methods from topographical aspects are studied for this purpose. Three main harvesting methods studied in this paper are : shortwood method, longwood method and full tree method. This study shows : the shortwood method is suitable for low, the longwood method for medium, the full tree method for high topographical conditions. For the logging methods, the focus of the study is on various ground based logging systems by animalpower, manpower, gravitation, wheeled & crawler vehicle and cable. The factors limiting the coverage of logging operation are slope and logging distance. The cable crane logging methods are classified by logging distance into short distance(to 300 or 400m), middle distance(to 700 or 800m) and long distance cable crane methods (over 700 or 800m). The wheeled vehicle method shows serious damages to forest resources, whereas the logging by log-line of the gravitation logging method and cable crane method tend to minimize such damages. The wheeled & crawler vehicle method also shows difficult to apply in the high slope conditions, whereas cable crane method can be applied to maximum 120% steep slope and uphill conditions.

• Journal of Korean Orthopaedic Sports Medicine
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• v.5 no.2
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• pp.123-128
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• 2006

Purpose: Surgical reconstruction is usually indicated for type II distal clavicle fracture due to high rate of nonunion and delayed union. We report the clinical outcome of a surgical technique for type II distal clavicle fracture using Mersilen tape and K-wire. Materials and Methods: From 1999 through 2003, this technique has been used on 11 patients with type II distal clavicle fracture. The procedure consist of fracture reduction with a Mersilene tape, repair of torn coracoclavicular ligament, and K-wire fixation of the fracture fragment. All patients with at least 12 months of complete postoperative follow-up were included for functional and radiographic evaluation. We used simple X-ray and UCLA scoring system and constant scoring system for evaluation at last follow up in OPD. Results: Solid union of the fracture could be achieved at 11 weeks after operation in all patients. All patients could return to the same level of preinjury activity. Good and excellent results were obtained in all patients according to UCLA system. Conclusion: This technique was simple procedure and allowed for stable fixation with early mobilization and early return to work and sports.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.1
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• pp.53-59
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• 2013

In an intra-alveolar root fracture (IARF) of a primary tooth with severe mobility and displacement, extraction and periodic-follow-up is the choice of recommended treatments because of the fear of aspiration of the mobile tooth and the possibility of damage in the permanent succeeding tooth. However, repositioning and splinting are presented as a fresh proposal recently. In case of extracting a primary incisor, many problems occur; esthetic problems; functional problems such as pronunciation and mastication; space loss; and psychological and social problems. Therefore, the best treatment is conservation of the primary tooth. The aim of this report was to suggest the conservative treatment of an Intra-alveolar root fracture of the primary central incisors with severe mobility and displacement based on two cases that describe the diagnoses, treatments and follow-ups (mean period: 27-month). All cases have been treated by reduction and immobilization by resin wire splint (RWS) (mean period: 6-week). Both cases were followed up until the successors were erupted. There have been no complications such as pain, pulp necrosis, periapical lesion, displacement of permanent tooth germ, eruption disturbance and etc.

• Elastomers and Composites
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• v.36 no.2
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• pp.111-120
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• 2001

Mechanical properties and their adhesion behavior with zinc- and brass-plated steel cords of natural rubber/acrylonitrile-butadiene blend compounds were investigated as a function of blend ratio. The Mooney viscosity and stress relaxation time were found to be lowered with increasing NBR content. Tensile modulus generally increased with increasing NBR content. Tensile stress at break stayed constant up to about 40 phr and showed minimum at $50{\sim}60 phr$, and thereafter increased with increasing NBR content. Strain at break decreased linearly below 50 phr, and above the level it showed nearly constant value. Based on the abrupt drops in elastic modulus and tan ${\delta}$ peak, the glass transition temperature of NR and NBR were found to be -55 and $-10^{\circ}C$, respectively. In the case of NR/NBR blend compounds, two distinct transition points were observed and each transition position was not affected by NBR level indicating an incompatible nature of NR/NBR blend system. The pullout force and rubber coverage decreased to the level of about 40% to that of pure m compound, when the 50 phr of NR was replaced by NBR. However, the pure NBR compound showed the comparable adhesion performance with NR(${\sim}90%$). The sulfur concentration was found to become lower with the increased NBR content at the adhesion interface based on the Auger spectrometer results, representing a lack of adhesion layer formation, and this was explained for a possible cause of low adhesion performance with adding NBR.

• Journal of Sericultural and Entomological Science
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• v.46 no.1
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• pp.1-5
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• 2004

Rutin has many beneficial effects on human health. It was established that rutin antagonizes the increase of capillary fragility associated with hemorrhagic disease, reduces high blood pressure, decreases the permeability of the vessels, and has an antiedema effect, reduces the risk of arteriosclerosis, and shows antioxidant activity. Rutin analysis with mulberry fruits was carried out by high-performance liquid chromatography (HPLC) to reveal the possibility of source of functional food. As a result, mean content of fifty accessions was 0.14±0.050% DW. Among the tested fifty accessions, 'Sabangso' was showed the highest rutin in 0.29%DW, whereas 'Simseol' was the lowest content in 0.05% DW. Also, we researched the change of rutin content according to harvested date. The rutin contents of earlier harvested groups were higher than later harvested groups. Simultaneously, fruity characteristics as well as rutin content were researched and analyzed to select the functional mulberry varieties for the production of fruit. From the six accessions which were contained high rutin content, we selected three suitable varieties such as 'Ficus', 'Kangsun', and 'Palcheongsipyung'.