• Journal of the Korea Institute of Building Construction
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• v.4 no.2
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• pp.113-118
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• 2004

This study is a basic experiment on quality management of the compression strength of high strength concrete, aiming. at quality management of high strength mass concrete by giving the temperature hysteresis of the mass test pieces to managerial test pieces. Different from ordinary concrete, high strength concrete generally shows the temperature high rising caused by hydration heat inside the concrete. It is known that, in mass concrete, thermal stress occurs due to the difference in temperature between the inside and the outside, which causes a significant difference in compression strength between structure beams and managerial test pieces. It is also reported that there is a large difference between the compression strength of cylindrical managerial test pieces of standard underwater curing and the strength of structure beam concrete. Thus, this study made concrete test pieces in an optimal mix ratio for each strength level, and also created thermal insulation curing box and managerial test pieces. Then it carried out comparative analysis in relation to core strength and suggested equipment and a technique that can control the strength of high strength concrete mass more conveniently and accurately.

• Korean Journal of Adult Nursing
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• v.17 no.2
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• pp.298-309
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• 2005

Purpose: The purpose of this study was to investigate the effect of a comprehensive rehabilitation program on grip strength, pinch strength, the shoulder joint function, flexibility, and fatigue in mastectomy patients. Method: The subjects were fifty-five women with breast cancer (27 in the control group and 28 in the experimental group). The subjects in the experimental group participated in a comprehensive rehabilitation program for 10 weeks, which was composed of education, stress management, exercise, and peer support group activity. Results: The results revealed that the increase in grip strength, key pinch, the shoulder joint function, and flexibility (Back & Reach test, Standing & Bending reach test) of the operated extremity, and the decrease in fatigue were significantly higher in the experimental group than in the control group. However, the results revealed that tip strength and palmar pinch of the experimental group increased but there was no significant difference from that of the control group. Conclusions: The 10-week comprehensive rehabilitation program showed much affirmative effect on physical function, and fatigue of breast cancer patients after mastectomy.

• Clinical and Experimental Pediatrics
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• v.48 no.12
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• pp.1295-1309
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• 2005

Nowadays, the nutritional deficits are rarely seen in Korea. However, an increased availability of the highly palatable energy dense, nutrient-poor foods increases the risks of obesity and deficits of vitamins and minerals in the general population. Also, optimum intake of vitamins and minerals, which varies with age and genetic back ground, might not suffice the poor, young, obese, and elderly people. Young girls and individuals participating in weight reductions and aesthetic components are prone to micronutrient deficiencies because they restrict food intake and specific micronutrient rich foods. An inadequate intake of vitamins or minerals is associated with reduced physical performance and exercise capacity, increased obesity, decreased cognitive function, increased DNA damages such as single- and double-stranded breaks or oxidative DNA lesions, and accelerated aging process and increased neuronal damages with mitochondrial oxidative decay. Most of these deleterious effects of the deficit could be prevented by a one tablet of multivitamins with a good balanced diet. High dose B vitamins are frequently administered to overcome the metabolic inadequacy to the people with the less functional enzymes with increased Km values for their coenzymes due to the single gene mutation or due to the single nucleotide polymorphisms. And some certain antioxidant vitamins are also used in large quantities to overcome the oxidative stress and to repair the damages. In this review, new nutritional concepts of some vitamins and minerals, which are widely used and useful for the children, will be discussed.

• The Journal of Korean Medicine
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• v.30 no.4
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• pp.142-161
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• 2009

Objectives: There are many unknowns surrounding Jeong-Jo's death. To better understand Jeong-Jo's death, we closely inspected his medical records from the 20 days before his death in The Annals of the Chosun Dynasty (朝鮮王朝實錄) and Seungjeongwon Ilgi (承政院日記), Understanding medical treatment before death, we can correctly trace the cause of Jeong-Jo's death. Methods: According to The Annals of the Chosun Dynasty (朝鮮王朝實錄) and Seungjeongwon Ilgi (承政院日記), we examined his medical records between June 14 and June 28 of 1800, as to the change in chief complaint, cold and heat, thirst, syndrome differentiation, the opinions of Jeong-Jo, and the opinions of doctors, The original work, The Annals of the Chosun Dynasty and Seungjeongwon Ilgi were provided by NIKH (The National Institute of Korean History). The Korean translation of The Annals of the Chosun Dynasty was also provided by NIKH. Seungjeongwon Ilgi (original work written in Chinese characters) was directly translated into Korean by the study author. Results: 1. Jeong-Jo's is likely to have died of septicemia caused by an abscess on his back. 2. The cause of Jeong-Jo's death could be stroke due to hypertension, mental stress, and 'Wha (火) disease' Conclusions: The dominant view that Jeong-Jo was murdered by poison is not likely.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.109-112
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• 1997

The Hydrodynamic performance of the trileaflet polymer prosthetic valves depends on the design of the leaflet and the physical properties of the leaflet membrane. In order to study the effect of leaflet membrane elasticity on the hemodynamic performance of trileaflet prosthetic valve, leaflet membranes are manufactured using two different polymers - Biospan and Tecoflex SG-93A. The hemodynamic performance parameters are measured under steady and physiological pulsatile flow, and compared with monoleaflet polymer valve(floating valve) and bileaflet mechanical valve(St. Jude Medical valve). Well designed trileaflet valve shows the lowest mean pressure drop among the tested valves. The trileaflet valves with Biospan membrane show lower pressure drop and back low comparing to those with Tecoflex membrane. More elastic membrane may provide wide opening area during systole and close membrane ree edge contact during diastole. Durability of trileaflet valves are also tested in vitro. Trileaflet valves with non-uniform membrane thickness ail within 17 days because of stress concentration. Trileaflet polymer valves with uniform membrane thickness perform well over 55 days without failure.

• Journal of Korean Society for Quality Management
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• v.38 no.4
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• pp.504-511
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• 2010

A fuze detonator comprising star shells is an important device so that its failure usually leads to failure of the shells. In this paper, accelerated degradation tests of RD1333 (lead azide) using temperature stress were performed, and then degradation data of explosive power for the detonator were analyzed to predict the storage lifetime of detonator. Degradation data analysis to estimate the storage lifetime is based on a distribution-based degradation process. Statistical distribution parameters of explosive power degradation measures at each time were estimated for each temperature level, and then reliability of the detonator for each accelerated temperature level was estimated using both time-varying distribution parameters and critical level of explosive power. Arrhenius model was applied to estimate storage lifetime of the detonator under the field temperature condition. Accelerated distribution-based degradation analysis to estimate storage lifetime is explained in detail, and estimation results are compared to field data of storage lifetime in this paper.

• Tribology and Lubricants
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• v.30 no.2
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• pp.77-85
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• 2014

This study set out to predict the load capacity and rotordynamic coefficients of tilting-pad journal bearings, taking the pivot stiffness into account. The analysis uses rocker-back (cylindrical) and ball in socket (spherical) pivot models, both of which are based on Hertzian contact stress theory. The models ascertain the non-linear elastic deformation of the pivots according to the applied load, pivot geometry, and material properties. At present, the Reynolds equation for an isothermal, isoviscous, and incompressible fluid is used to calculate the film pressure by using the finite-element method, after which the Newton-Raphson method is used to simultaneously find the journal center location, pad angles, and pivot deflections. The bearing analysis, excluding the pivot models, is validated using predictions those are readily available in the literature. As the rotor speed increases, the predicted journal eccentricity and damping coefficients decrease, but the stiffness coefficients increase, as expected. Most importantly, the implementation of the pivot models increases the journal eccentricity but significantly decreases the stiffness and damping coefficients of the tilting-pad journal bearings.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.389-394
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• 2003

In this paper, a shape optimization technique is applied to design of an air-conditioner mounting bracket. The mounting bracket is a structural component of an engine, on which bolts attach an air-conditioner compressor. The air-conditioner mounting bracket has a large portion of weight among the engine components. To reduce weight of the bracket, the shape is optimized using a finite element software. The compressor assembly, composed of a compressor and a bracket is modeled using finite elements. An objective function for the shape optimization of the bracket is the weight of the bracket. Two design constraints on the bracket are the first resonant frequency of the compressor assembly and the fatigue life of the bracket. The design variables are the shape of the bracket including thickness profiles of the front and back surfaces of the bracket, radius of outer bolt-holes, and side edge profiles. The coordinates of the FE nodes control the shape parameters. Optimal shapes of the bracket are obtained by using SOL200 of MSC/NASTRAN.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.10
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• pp.89-96
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• 2009

In recent years, there has been a considerable interest in the application of super plastic forming in the aircraft and automotive industries. This requires a detailed design of the technological process in order to exploit its peculiar potentialities better. Nowadays, the finite element method is used to plan the sheet metal forming processes whose simulation requires determination of material constants for super plastic materials. The present work is aimed to show a simple method to characterize super plastic materials duplex stainless steel which was formed by a constant gaspressure to hemispheres with and without back pressure. The forming operation was performed using an in-house designed and built biaxial forming apparatus. The temporal change of dome heights of hemispheres were measured for applying the pressures. The flow stresses and strain rates developed at the top of the dome during the forming step were shown to follow closely the flow stress - strain rate relationship obtained from the strain rate change tests performed at the same temperature.

• Transactions of Materials Processing
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• v.17 no.8
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• pp.570-578
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• 2008

A flexible forming apparatus is composed a number of punches which have spherical pin tip shape instead of conventional solid die. The flexible forming tool consisted of punch array in a matrix form was proposed as an alternative forming method to substitute the conventional line heating method which use heat source to induce residual stress along specified heating lines. In this study, application of the flexible forming process to the small scale curved plate forming was conducted. Numerical simulations for both solid and flexible die forming process were carried out to compare the shape of the products between flexible and conventional die forming process. In addition, spring-back analysis was conducted to figure out the feasibility of the flexible forming process comparing with the die forming process in view of final configuration of the specimens. Moreover, experiment was also carried out to confirm the formability of the process. Consequently, it was confirmed that the flexible die forming method has capability and feasibility to manufacture the curved plates for shipbuilding.