• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.1
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• pp.162-167
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• 2002

An automotive wheel bearing is one of the most important components to guarantee the service life of a passenger car. The endurance life of a bearing is affected by many parameters such as material properties, heat treatment, lubrication conditions, temperature, loading conditions, bearing geometry, internal clearance and so on. In this paper, we analyze the relation between loads and deformations of wheel bearing units. On the basis of it, we calculate the endurance life of wheel bearing units and suggest a method to determine the initial contact angle to achieve a maximum endurance life with considering stress concentration.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.04a
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• pp.425-428
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• 1994

Non-uniform minute deformation of a cylinderical workpiece resulted from the heat treatment process prior to the grinding makes it diffeclt to control the approaching feedrate of a grinding wheelto a workpiece optimallywithout on-site detection of the grinding states in the plunge grinding. The 4-stage model of the plunge grinding process is proposed according to the state of contact between grinding wheel and workpiece ; precontact, partial contact, entire contact and spark-out. Despite of being scrious to the precision of workpiece finished, the duration of spark-out is determined empirically. The purpose of this research is to develop a monitoring/control system for saving non- production time and setting the optimal spark-out time based on sensor information in the plunge grinding using AE and ultra sonic sensor.

• Tribology and Lubricants
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• v.12 no.1
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• pp.22-28
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• 1996

This study was undertaken to investigate the dry wear characteristics and mechanism of KP-4M steel for plastic molding against SKD 61 hardened by heat treatment. The wear test was carried out under different conditions such as sliding speed, contact pressure, sliding distance, with frictional tester of pin on disc type. The wear loss on variation of sliding speed was little in lower speed range below 0.5 m/sec and in higher speed range above 1.5 m/sec,'but wear loss was high in intermediate speed range. The critical sliding speed, which showed the maximum value of specific wear rate, became lower with increased contact pressure. Increasing the contact pressure, the critical sliding distance Lcr which the wear mechanism changes from severe wear to mild wear was increased due to the decrease of oxidation reaction velocity. Through this study we suggested a model of generation and elimination process of wear debris of KP-4M steel for plastic molding.

• Journal of Information Technology Services
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• v.10 no.2
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• pp.21-39
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• 2011

After ten years from the introduction of CRM systems, many companies reevaluate CRM from the perspective of customers. This paper classifies CRM activities at the contact points with customers and investigates the effect of CRM activities on perceived benefits and the effect of perceived benefits on behavioral intention in the Korean cosmetic industry. The result showed that contact management and complaint handling affected social benefits and that customers perceived confidence benefits from contact management, complaint handling, and churn management. Special treatment benefits were affected by all CRM activities including compensation management. Finally, all kinds of benefits had effects on behavioral intention such as recommendation intention and repurchase intention.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.738-739
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• 2006

This paper will describe a powder and processing method that facilitates single press-single sintered densities approaching $7.5g/cm^3$. At this sintered density, mechanical properties of the powder metal (P/M) component are significantly improved over current P/M technologies and begin to approach the performance of wrought steels. High performance gears have the added requirement of rolling contact fatigue durability that is dependent upon localized density and thermal processing. Combining high density processing of engineered P/M materials with selective surface densification enables powder metal components to achieve rolling contact fatigue durability and mechanical property performance that satisfy the performance requirements of many high strength automotive transmission gears. Data will be presented that document P/M part performance in comparison to conventional wrought steel grades.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.668-673
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• 2003

A wheel and axle failure can cause a derailment with its attendant loss of life and property. The service conditions of railway vehicles have become severe in recent years due to a general increase in operating speeds. Damages of railway wheel are a spalling by wheel/rail contact and thermal crack by braking heat etc. One of the main source of damage is a residual stress. therefore it is important to evaluate exactly. A Residual stress of wheel is formed at the process of heat treatment when manufacturing. it is changed by contact stress developed by wheel/rail contact. Distributions of residual stress vary according to a magnitude of wheel load, a magnitude of friction when acceleration and deceleration. The objective of this paper is to estimate the influence of wheel motion on the residual stress distribution in the vicinity of the running surface.

• Membrane and Water Treatment
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• v.7 no.1
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• pp.71-86
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• 2016

The present study deals with a numerical simulation for the transport phenomena in three configurations of Membrane Distillation (Air Gap, Direct Contact and Sweeping Gas Membrane Distillation) usually used for desalination in order to make an objective comparison between them under the same operating conditions. The models are based on the conservation equations for the mass, momentum, energy and species within the feed saline and cooling solutions as well as on the mass and energy balances on the membrane sides. The theoretical model was validated with available data and was found in good agreement. DCMD configuration provided the highest pure water production while SGMD shows the highest thermal efficiency. Process parameters' impact on each configuration are also presented and discussed.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.208-213
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• 2002

Railway wheel and axle are the most critical components in railway system. A wheel and axle failure can cause a derailment with its attendant loss of life and property. The service conditions of railway vehicles have become severe in recent years due to a general increase in operating speeds. Therefore, more precise evaluation of wheelset strength and safety has been desired. Damages of railway wheel are a spatting by wheel/rail contact and thermal crack by braking heat etc. One of the main source of damage is a residual stress. therefore it is important to evaluate exactly. A Residual stress of wheel is formed at the process of heat treatment when manufacturing. it is changed by contact stress developed by wheel/rail contact and thermal stress from heat induced in braking. The objective of this paper is to estimate the variation and magnitude of the residual stress of railway wheel.

• Journal of Veterinary Science
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• v.22 no.2
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• pp.19.1-19.5
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• 2021

A 7-month-old intact female Persian cat was diagnosed with symblepharon accompanied by epiphora, brownish ocular discharge, and ocular discomfort in the left eye. Superficial keratectomy (SK) was performed to remove adhesions between the conjunctiva and cornea. To prevent re-adhesion after SK, the detached conjunctival tissue was sutured to the corneal limbus, and a soft contact lens (SCL) was inserted and a partial temporary tarsorrhaphy was performed. The SCL and tarsorrhaphy sutures were maintained for 22 days, and symblepharon did not recur 347 days postoperatively. SK combined with SCL is a relatively easy and cost-effective surgical option for feline symblepharon.

• Advances in pediatric surgery
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• v.5 no.1
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• pp.69-74
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• 1999

Condyloma acuminata, an uncommon disease m the pediatric patients, is being reported with increasing frequency in both adults and children. During the last 10 years, we managed 11 children with condyloma acuminata of the anogenital area. The patients' age at presentation varied from 9 months to 11 years, and boys outnumbered girls by a ratio of 2 : 1. The lesions were found in the perianal area in 9 patients and the genital area in 2. No history of sexual contact or abuse could be elicited. Although the exact mode of transmission of human papillomavirus(HPV) couldn't be defined, maternal-infant transmission at birth and close nonsexual family contact were the main possible causes of HPV infection in our patients. Our experience suggest that fulguration of the warts and concomitant excision with scissors of the larger lesions are the most satisfactory method of treatment in children. However, condyloma acuminata have high recurrence rate despite these treatments. Viral typing and careful epidemiological investigation on a larger series of patients may clarify the causative factors and effective modalities of treatment in childhood anogenital condyloma acuminata.