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Yangju, South Korea

Park J.H.,Korea University | Kim K.J.,Seojeong College | Lee J.W.,Kookmin University | Yoon J.K.,Gachon University
International Journal of Automotive Technology

It is well known that the targeted fuel efficiency could only be achieved by more than 40% reduction of the vehicle weight through improved design and extensive utilization of lightweight materials. In order to obtain the goal of the weight reduction of automobiles, the researches about lighter and stronger suspension link have been studied without sacrificing the safety of automotive suspension. In this study, the weight reduction design process of suspension link could be proposed based on the variation of von-Mises stress contour by substituting an aluminum alloys (A356) having tensile strength of 310 MPa grade instead of STKM11A steels. In addition, the effect of the stress and stiffness on shape variations of the suspension link were examined and compared carefully. It could be reached that this approach method could be well established and be contributed for light-weight design guide and the optimum design conditions of the automotive suspension link development. © 2015, The Korean Society of Automotive Engineers and Springer-Verlag Berlin Heidelberg. Source

Cho K.,Seojeong College | Kim J.M.,Seoul National University | Kim M.H.,Chungbuk National University | Kang S.S.,Chonnam National University | And 2 more authors.
European Surgical Research

Differential diagnoses for canine bone disease are commonly based on radiography. However, scintigraphy is a nuclear scanning test to trace bone healing during stress fracture and osteomyelitis and thus can be used to probe the osseointegration process in vivo in the context of the dental implant. The purpose of this study was to explore the possibility of using noninvasive scintigraphy to probe the effect of platelet-rich plasma (PRP) to enhance osseointegration of the implant and to confirm the result with a parallel histological examination in adult beagle dogs. Two independent calcium phosphate-coated titanium screw implants 8 mm in length and 4 mm in diameter were inserted into each tibia in 4 dogs (4 implants/animal, total = 16). The PRP-treated group was deposited with 0.5 ml of PRP into the drill hole in the right tibia; the control group was instilled with 0.5 ml of saline into the drill hole in the left counterpart before titanium screw implantation. Radiography of the implanted tibias showed complete osseointegration but no osteomyelitis. No difference in the ossification of the peri-implant bone on the radiographs was observed between the two groups during the experimental period. However, the scintigraphic findings revealed obvious differences in bone uptake between the two groups. The higher bone uptake in the PRP-treated group significantly increased bone activity and faster bone regeneration compared to the control group (p < 0.05) at 4 weeks after implantation. The percentage of the bone-to-implant contact on histological examination in the PRP-treated group showed dense cortical bone formation in close contact with the metallic surface of the titanium implant (p < 0.05). Quantitative histological analysis correlated well with that of the scintigraphic evaluation as revealed by Pearson correlation analysis (r = 0.72, p < 0.05). Thus, scintigraphy is a sensitive and noninvasive method suitable for osseointegration of the implant in vivo. © 2013 S. Karger AG, Basel. Source

Kim J.,Seojeong College | Kwon J.,Hanyang University | Noh G.,Chungnam National University | Lee S.S.,Hanyang University
Nutrition Research and Practice

A food allergy is an adverse health effect arising from a specific immune response that occurs reproducibly upon exposure to a given food. In those with food allergies that are thought to cause aggravation of eczema, food avoidance is important. The objective of this study was to research the nutritional status of patients with food allergies. A total of 225 subjects diagnosed with atopic dermatitis underwent a skin prick test as well as measurement of serum immunoglobulin E. Food challenge tests were conducted using seven food items: milk, eggs, wheat, soybeans, beef, pork, and chicken. At post-food challenge visits to the test clinic, participants completed a three-day dietary record, which included two week days and one weekend day, in order to evaluate energy intake and diet quality during the challenge. We analyzed nutrient intake based on differential food allergens. Subjects with a food allergy to milk showed lower intake of Ca, Zn, and vitamin B2, and subjects with a food allergy to egg showed lower intake of vitamin A, B1, B2, niacin, and cholesterol. Subjects with a food allergy to wheat and soybean showed lower intake of Ca, P, Fe, K, Zn, vitamin B2, vitamin B6, and niacin; and subjects with a food allergy to beef, pork, and chicken showed lower intake of Fe and higher intake of K, vitamin A, B2. Subjects with atopic dermatitis were lacking in several nutrients, including vitamin A and vitamin C. A greater number of food allergies showed an association with a greater number of nutrient intake deficiencies. Allergen avoidance is the basic treatment for atopic dermatitis. However, when the allergen is food, excessive restriction can lead to nutrition deficiency. Findings of this study suggest the necessity for enhanced nutritional education in order to provide substitute foods for patients with food allergies who practice food restriction. © 2013 The Korean Nutrition Society and the Korean Society of Community Nutrition. Source

Bae J.,Kyungpook National University | Lee S.,Kyungpook National University | Kim B.C.,Kyungpook National University | Cho H.H.,Hanyang University | Chae D.W.,Seojeong College
Fibers and Polymers

Polyester-based thermoplastic elastomer (Hytrel®) was melt-compounded with multi-walled nanotubes (MWNTs) using an internal mixer and the changes in the thermal, electrical and rheological properties were investigated using a range of nanotube contents (from 0.1 to 7 wt%). Even at nanotube concentrations as low as 0.1 wt%, the crystallization temperature was remarkably elevated by 15 °C and it increased further up to 22 °C with a 5 wt% loading. On the contrary, the melting temperature increased by 2 °C with 0.1 wt% MWNTs and it was slightly decreased by further additions of MWNTs. Electrical conductivity measured by the four probe method was detected from the 1 wt% MWNTs, indicative of electrical percolation. In addition, MWNTs starting from 4 wt% and above had no significant effect on the electrical conductivity, while it rapidly increased with nanotube contents below 4 wt%. Dynamic rheological properties were measured using a strain controlled rotational rheometer. The complex viscosity increased with MWNT contents giving an abrupt increase between 0.5 and 1 wt% loadings. In addition, the storage and loss modulus increased in a different manner depending on the range of the nanotube concentration. In the Cole-Cole plot, the slope of the nanocomposites decreased from 1.63 to 0.74 with increasing nanotube contents. In the Casson plot, the addition of MWNTs up to 0.5 wt% did not show any yield behavior giving an extremely low value for the yield stress, but further additions of nanotubes increased it notably. The presence of nanotubes in the elastomer increased the relaxation time with nanotube contents and their effect became weak as the frequency increased. © 2013 The Korean Fiber Society and Springer Science+Business Media Dordrecht. Source

Kim K.J.,Seojeong College | Lee Y.-C.,Korea Institute of Industrial Technology | Park J.-H.,Korea University
Materialwissenschaft und Werkstofftechnik

The case of an electric vehicle, where a motor and a battery system can be substituted for an engine and a transmission system, comprises a very fascinating power source. However, due to the low power performance of the motor system, the weight reduction of the electric vehicle for the increase of the efficiency is necessary. For the research of the new vehicle, the benchmarking of developments leading companies about the electric vehicle was considerably surveyed first. Then the CAE (computer aided engineering) simulation of the full vehicle (Metro by Geo Co.) model was performed. Among these systems, as the weight of the batteries are comparably high (200 ∼ 300 kg or over), the problem of the safety performance can occur where the motor and the battery are situated in the vehicle location (in the front engine room, center floor or rear trunk position). In addition, the reinforcement degree can differ following as the motor and the battery position in the vehicle in order to satisfy the vehicle safety and it can induce the weight variation of the vehicle. Therefore, the effect of strength performance on the layout of the power train system (mainly battery) was clarified by using CAE (computer aided engineering) and the optimized position of the power train system considering weight balancing of the electric vehicle was suggested in the present study. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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