• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.760-761
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• 2008

This paper deals with the core loss as well as torque characteristics according to the change of stator shape in an interior permanent magnet synchronous motor (IPMSM). The finite element method and functional core loss data obtained by the steinmetz equation are used in order to estimate the core loss. To minimize the core loss caused by the shape of tooth tip, slot-area and volume of permanent magnet, those are all the same in each model. In the end, the ratio between tooth width and yoke thickness to minimize the core loss in the IPMSM is presented in this paper.

• Journal of Ceramic Processing Research
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• 제13권spc2호
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• pp.363-367
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• 2012

DLC (diamond liked carbon) coating of the tungsten carbide (WC) alloy core surface for molding a glass aspheric lens improves the quality of glass lens and the molding core and is characterized by high hardness, high elasticity, abrasion resistance and chemical stability. In this study, the effect of DLC coating of a thin film by means of the filtered AIP (arc ion plating) technique was examined on Ra and shape of the coated surface. Roughness before and after DLC coating was measured and the result showed that the roughness was improved after coating as compared to before coating. It was observed that DLC coating of the WC alloy core surface for molding had an effect on improving the roughness and shape of the core surface. It is considered that this will have an effect on improving abrasion resistance and the service life of the core surface.

• 한국전기전자재료학회논문지
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• 제19권4호
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• pp.386-390
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• 2006

Global consumption of aspheric lens will expand rapidly due to golbal transformation of the electronics based industry to optics based mechatronics. Especially, F-Theta lens is one of important parts in Laser Scanning Unit(LSU) because it affects the optical performance of LSU dominantly. Non axisymmetric machine based processing techologies are required to obtain high accuracy in utlra-precision aspheric core, the most important component in plastic injection molded F-Theta lens assembly. In this study, the core with non-axisymmetric aspheric shape which is used to emit the F-Theta lens was processed using the ultra precision processing technology and the shape accuracy of the core was measured. And the results there of were evaluated and compared with the emitted shape accuracy of F-Theta lens.

• 한국주조공학회지
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• 제36권1호
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• pp.10-17
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• 2016

Numerical analysis has been performed to evaluate effect of the shape variables such as core length, slot width and slot length on misrun in aluminum die casting process for motor rotor. The predictive method for misrun in diecasting process was established by comparing the result of numerical analysis and an actual motor rotor. Solidification modulus was introduced to predict quantitatively the castability of aluminum diecasting process for motor rotor. It was found that there are minimum critical solidification modulus and slot width to prevent misrun according to core length through diecasting limit diagram proposed using the predictive method. The critical solidification modulus and slot width increase as core length increases to prevent misrun of aluminum motor rotor in diecasting process. Based on the results, the design criteria of slot shape to prevent misrun of aluminum motor rotor with various core length were established.

• Human Ecology Research
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• 제59권1호
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• pp.13-21
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• 2021

In order to examine the changes in the appearance properties and the post-adhesion appearance properties of Hanji yarn blended fabrics : 100% Hanji yarn fabric, two kinds of cotton / Hanji yarn blended fabrics and 100% cotton fabric, were selected and fused with three kinds of interlinings. After fusing, changes of standardized KES values were examined. 1. W/T, B/W of Hanji yarn blended fabrics was higher than that cotton fabric. WC/W, 2HB/W, 2HB/B, and 2HG/G values of Hanji yarn blended fabrics are lower than cotton fabric. This means that the Hanji yarn was mixed, shape retention, wrinkle recovery was improved, and the drape property was lowered. 2. After fusing, W/T, shape retention, wrinkle recovery of Hanji yarn blended fabrics increased, and WC/W values of Hanji yarn blended fabrics decreased. The wrinkle recovery property of Hanji yarn blended fabrics were improved; however, the 2HG/G value of Hanji yarn fabric increased due to fusing, and the wrinkle recovery property of Hanji yarn fabric decreased. 3. In the selection of adhesive core, I1 adhesive core is excellent in terms of shape stability and wrinkle recovery; however, an I3 adhesive core is recommended for drape and silhouette formation. When the fabric of the adhesive core was PET, it was found to penetrate better between the fabrics during adhesion than the case of cotton fabrics.

• 한국산업융합학회 논문집
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• 제26권2_2호
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• pp.327-332
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• 2023

As interest in eco-friendly and fuel-efficient electric vehicles has increased globally, there has also been a growing interest in the efficiency, vibration, and noise of motors for electric vehicles Electric vehicles generally have significantly lower driving ranges per charge compared to the maximum driving range per fueling of internal combustion engine vehicles. Additionally, there are issues with various vibrations and noise generated by the motor that can cause discomfort for passengers. Therefore, research is necessary to reduce losses, vibration, and noise of the motor to improve the driving range of electric vehicles. IPMSM with a purchased design can obtain additional reluctance torque by utilizing the difference in inductance between the d and q axes. However, due to this reluctance torque, torque ripple occurs larger than other motors. The increase in torque ripple also increases noise and vibration. Since the reluctance torque, which is the main cause of torque ripple, is determined by the shape of the motor components, torque ripple can be reduced through shape optimization. In this paper, a rotor shape for reducing torque ripple and core loss that causes vibration, noise, and efficiency to decrease of IPMSM for electric vehicles was proposed. Optimization design was carried out by changing the shape of the q-axis path of the rotor to reduce the difference in inductance of the d and q-axis of the rotor. Finally, in order to verify the validity of the design variables derived through the optimal design, the original model and the improved model were compared through the FEM. Compared to the original model, the improved model's torque verifying ripple was reduced by about 62% and core loss was reduced by about 29%, the superiority of the improved model.

• 한국환경복원기술학회지
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• 제16권4호
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• pp.53-63
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• 2013

The purpose of this study is to analyze impacts of the forest fragmentation caused by development project. Furthermore, to investigate the applicability of landscape indicator when 'Feasibility of forest land conversion to other use' is conducted. The study site was consisted of golf course development and road construction. It is to compare before and after impacts of areal and linear development. As for the methods, selecting landscape indices, clustered into 3 Categories have been utilized. Category I was concerned with 'size of forest patches', II as 'shape of forest patches', and III as 'Core Area' These were calculated by FRAGSTATS, the program for analyzing fragmentation. The results showed that linear development caused more fragmented than areal development projects. Also, patch size, patch shape and core area are related to impacts of development, while Patch size decreased, patch shape and core area increased after development. Therefore, it is necessary to minimize the impacts of forest by considering fragmentation when development project is planned.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.794-795
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• 2006

Metal powder for dust core application was developed. The powder can be produced improved high-pressure water atomization process. The process has produced powder of spherical shape and lower coercivity. The dust core obta ined shows lower core loss.

• Advances in concrete construction
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• 제11권4호
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• pp.271-284
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• 2021

This study aims to trace the response of twelve one-way sustainable concrete hollow-core slabs made by reducing cement content and using replacement of coarse aggregate by plastic aggregate. The trial mixes comprise the 25, 50, 75, and 100% replacement of natural coarse aggregate. The compressive strength of the resulting lightweight concrete with full replacement of coarse aggregate by plastic aggregate was 28 MPa. These slabs are considered to have a reduced dead weight due to using lightweight aggregate and due to reducing cross-section through using voids. The samples are tested under two verticals line loads. Several parameters are varied in this study such as; nature of coarse aggregate (natural or recycled), slab line load location, the shape of the core, core diameter, flexural reinforcement ratio, and thickness of the slab. Strain gauges are used in the present study to measure the strain of steel in each slab. The test samples were fourteen one-way reinforced concrete slabs. The slab's dimensions are (1000 mm), (600 mm), (200 mm), (length, width, and thickness). The change in the shape of the core from circular to square and the use of (100 mm) side length led to reducing the weight by about (46%). The cracking and ultimate strength is reduced by about (5%-6%) respectively. With similar values of deflection. The mode of failure will remain flexural. It is recognized that when the thickness of the slab changed from (200 mm to 175 mm) the result shows a reduction in cracking and ultimate strength by about (6% and 7%) respectively.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.451-452
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• 2006

The influence of Hi-flux powders characteristics on the performance of magnetic powder cores was studied. It was found that different cooling rate and nozzle configuration could change the shape and microstructure of powders. Smooth surface and spherical shape of powders were beneficial to improve DC bias performance and reduce core losses of magnetic powder core.