• Journal of Welding and Joining
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• 제35권2호
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• pp.1-5
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• 2017

Many microelectronic devices are miniaturizing the capacitance density and the size of the capacitor. Along with this miniaturization of electronic circuits, tantalum (Ta) capacitors have been on the market due to its large demands worldwide and advantages such as high volumetric efficiency, low temperature coefficient of capacitance, high stability and reliability. During a tantalum capacitor manufacturing process, arc welding has been used to weld base frame and sub frame. This arc welding may have limitations since the downsizing of the weldment depends on the size of welding electrode and the contact time may prevent from improving productivity. Therefore, to solve these problems, this study applies laser spot welding to weld nickel (Ni) and Au-Sn-Ni alloy using CW IR fiber laser with lap joint geometry. All laser parameters are fixed and the only control variable is laser irradiance time. Four different shapes, such as no melting upper workpiece, asymmetric spherical-shaped weldment, symmetric weldment, and, excessive weldment, are observed. This shape may be due to different temperature distribution and flow pattern during the laser spot cutting.

• 한국경영과학회지
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• 제39권2호
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• pp.97-109
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• 2014

This paper considers a reverse supply chain with simultaneous recovery of used products and manufacturing of brand-new ones. Recovered products are downgraded and have to be sold in a market different from that of brand-new products at a different price. In case of a shortage of recovered product inventory, a brand-new item, if available, can be offered at the price of a recovered product. In other words, one-way demand substitution is allowed. We address the joint decision of when to manufacture brand-new product, when to recover returned product, and how to control demand substitution to maximize the hybrid production system's profits. To this end, we propose a Markov decision Process model and investigate the structure of the optimal policy. Performance comparison is numerically implemented between the models with and without downward demand substitution option under different operating conditions of the system parameters.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.440-445
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• 2002

The characteristic equation for regenerative chatter loop including a delay element replaced by a rational function is presented by a linear differential-difference equation, accounting for the dynamics of the AMB controllers, the uncut chip thickness equation and the cutting process as well as the rigid spindle dynamics itself. The chatter stability analysis of a rigid milling spindle suspended by 5-axes active magnetic bearings(AMBs) is also performed to investigate the influences of the damping and stiffness coefficients of AMBs on the chatter free cutting conditions, as they are allowed to vary within the stable region formed by the AMB control gains. Several cutting tests varying the derivative gains of the AMB were performed to investigate the regenerative chatter vibrations, and it was concluded that the theoretical analysis results are in good consistency with the test results.

• 한국공작기계학회논문집
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• 제16권6호
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• pp.37-42
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• 2007

The purpose of this research is stability estimation of plant structure through classification and recognition about welding flaw in SWP(Spiral Welding Pipe). And, In this research, we used nondestructive test based on ultrasonic test as inspection method, and made up 2-axes inspection robot in order to control of ultrasonic probe on the SWP surface, and programmed to image processing and probabilistic neural network(PNN) classifying code by MATLAB programming. Through this process, we proved efficiency on the system of SWP stability Estimation.

• 대한안전경영과학회지
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• 제5권3호
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• pp.157-164
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• 2003

This paper studied about effects of the certificate of ISO 9000 in the manufacturing companies whose number of employee is under three hundred. First, most of company answered that acquiring the certificate of ISO 9000 is very helpful for the company management. therefore the company has the competence in the change of domestic and international economy. Second, after acquiring the certificate of ISO 9000, there were many improvements in company culture, quality control and business process productivity. As a result, the acquisition of the certificate of ISO 9000 system makes the company culture preparing the future to become a world first class company.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.278-279
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• 2006

The increasing demand for automotive industries to reduce the weight of the vehicles has led to a growing usage of Al alloy powder metallurgy (P/M) parts. In order to control the sintered microstructure and mechanical properties of the aluminium alloy powder metallurgical (P/M) parts, it is essential to establish a fundamental understanding of the microstructural development during the sintering process. This paper presents a detailed study of the effect of temperature and initial starting materials on the evolution of microstructure during the sintering of Al-Cu-Mg-Si blends for PM.

• 한국자동차공학회논문집
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• 제13권4호
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• pp.26-31
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• 2005

ITR(Inne. Tie Rod) is one of the core parts in an automobile steering system. The front wheels are connected to the steering system, which are controlled by steering wheel through the ITR. Improvement of assembling ITR is needed f3r drivers' satisfaction. Therefore, the parameters influencing the rotational torque were studied and analyzed. The useful results can be obtained, and could be applied to manufacture ITR. Through these manufacturing technologies, high quality ITR have been manufactured with high productivity.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.861-864
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• 2005

A LCD glass plate is supported by multi-pin and golf-tee type support. In the FEM analysis, the support condition is treated as simply supported boundary .condition. In this study, the optimization on the location of multi-simply support is conducted. The size optimization method of ANSYS 8.0 is used as the optimization tool to search for the optimal support location of LCD glass plate. In the manufacturing process, the support condition is a fatal factor of quality control of LCD production. From the results of optimization, deflection decreases 51% compared with the original model.

• 한국자기공명학회논문지
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• 제20권3호
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• pp.82-86
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• 2016

Ginseng is used as a medicinal ingredient. The quality control of species, age, origin and manufacturing process is important. The metabolome of ginseng about quality was studied in many reports. Almost studies carried out the extract of ginseng, however, the reproducibility cannot be obtained using extracted sample. In this study, powdery ginseng samples were analyzed using high resolution-magic angle spinning nuclear magnetic resonance (HR-MAS NMR)-based metabolomics except extraction step. Sample was measured three times using 600 MHz NMR spectrometer equipped with nano probe. Reproducibility can be enhanced using this method and the metabolic profiles of ginseng were identified and quantified.

• Interaction and multiscale mechanics
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• 제5권2호
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• pp.145-155
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• 2012

The thin-plate structure and the box-beam structure are two typical welded structures in railway vehicles. Because of their structure complexity, bigger size and multi-seams, welding residual distortion which occur in welding process bring unfavorable effect on the quality of welding products manufacturing and service. As a result, welding distortion forecasting and control become an important and urgent research topic in railway vehicles. In this paper, three different numerical methods are presented corresponding to three typical types of welded structures of railway vehicles and welding deformation are simulated. Consistence of numerical results and experimental data proves the correctness of models and feasibility of simulation methods.