• Korean Journal of Materials Research
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• v.17 no.7
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• pp.390-395
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• 2007

We systematically investigated the effects of InAs coverage variation, two-step annealing and an asymmetric InGaAs quantum well (QW) on the structural and optical characteristics of InAs quantum dots (QDs) by using atomic force microscopy (AFM), transmission electron microscopy (TEM) and photoluminescence (PL) measurement. The transition of size distribution of InAs QDs from bimodal to multi-modal was noticeably observed with increasing InAs coverage. By means of two-step annealing, it is found that significant narrowing of the luminescence linewidth (from 132 to 31 meV) from the InAs QDs occurs together with about 150 meV blueshift, compared to as-grown InAs QDs. Finally, the InAs QDs emitting at longer wavelength of $1.3\;{\mu}m$ with narrow linewidth were grown by an asymmetric InGaAs QW. The excited-state transition for the InAs QDs with an asymmetric InGaAs QW was not noticeably observed due to the large energy-level spacing between the ground states and the first excited states. The InAs QDs with an asymmetric InGaAs QW will be promising for the device applications such as $1.3\;{\mu}m$ optical-fiber communication.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.564-567
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• 2004

In the manufacture of integrated circuits, photolithography is the lowest yield step in present production lines. Electron beams form a powerful set of tools with which to attack this problem. Electron beams can be used to make patterns that are smaller than can a photolithography. We design a high voltage generator of electron beam manufacturing system. For this purpose, first, the configuration of electron beam manufacturing system was analyzed. Second, the basic configuration of a high voltage generator and test results were presented.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.30-35
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• 2003

Recently, with the rapid growth of information technology, many studies have been performed to implement web-based manufacturing system. Such technologies are expected to meet the need of many manufacturing industries those want to adopt E-manufacturing system for the construction of globalization, agility, digitalization to cope with the rapid changing market requirements. In this research, areal-time web-based machine tool and machining process monitoring system is developed as a first step fur implementing I-manufacturing system. In this system, main spindle motor current and feed current are measured using hall sensors. And the relationship between the cutting force and the spindle motor RMS current at various spindle rotational speed is obtained. Also, a rule-based expert system is developed in order to monitor the machining process effectively. Finally, developed system is applied to real machining process to verify the effectiveness.

• The Korean Journal of Food And Nutrition
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• v.33 no.4
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• pp.440-446
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• 2020

The purpose of this study was to derive the conditions for manufacturing rice porridge with optimum properties after reheating. The characteristics of rice porridge according to the soaking time, water addition rate, heating temperature, heating time, and cooling conditions were compared using the 'Samkwang' cultivar. In Step I, as the heating temperature increased, the weight change decreased and the viscosity increased, and the temperature known as the main factor of the gelatinization also appeared to affect the viscosity increase. In Step II, the viscosity and the texture properties was not significantly different as the soaking time was reduced, and 10 minutes was suitable because of due to the shortening effect of the total process time. In Step III, the residual heat was lowered by cooling after the rice porridge production, so the viscosity could be greatly reduced. Also, it was confirmed that the water addition rate of 900% and the heating temperature of 15 minutes were optimal manufacturing conditions. The next study will investigate the porridge processability of rice cultivars using these results.

• Korean Journal of Metals and Materials
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• v.47 no.12
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• pp.852-859
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• 2009

The manufacturing process of zirconium alloys is an import factor to increase their strength and corrosion resistance. In order to find an improved manufacturing process of zirconium alloys in both Zr-1Nb-1Sn-0.1Fe (Alloy-A) and Zr-1.5Nb-0.4Sn-0.2Fe-0.1Cr (HANA-4) for fuel guide tubes, sheet samples were prepared by applying two- and three-step processes that were controlled by an annealing and reduction condition. The mechanical strength and corrosion resistance of both alloys were increased by applying the twostep process rather than the three-step process. From a matrix analysis using TEM, the property improvement is related to the decrease of the precipitate mean diameter with an application of the two-step process. In a comparison of the strength and corrosion properties between Alloy-A and HANA-4, the performance of HANA-4 was feasible for application to fuel guide tubes.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.672-675
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• 1997

This paper proposes a structure of the control system for the step & scan exposure tool. The step & scan exposure tool is used for the manufacturing process of the semiconductor DRAM memory of giga bit. The control system employs the VME bus instead of the conventional ISA bus so that all control signals and data can be managed separately by the 4 VME-PCs for fast and fault-free flow of signals for multi-tasking. A high speed I/O card is equipped for the real-time monitoring and control of the sub module equipment. Then all the subsystems are integrated and aligned for the operation of the step & scan exposure tool with the VME bus and, I/O card.

• Korean Journal of Computational Design and Engineering
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• v.10 no.6
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• pp.412-420
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• 2005

The integration of CAD and CAM is critical for computer aided process planning. Recently, STEP has been emerged and utilized as a product data exchange standard format in CAD/CAM areas. The assembly information consists of assembly component relations, assembly features, assembly directions and mating conditions. The purpose of this study is to develop an efficient algorithm to extract assembly information directly from the STEP based files and to generate automatically assembly process plan from the extracted assembly features. The developed algorithms will generate assembly information codes for STEP(AICS). The results from this study can be a reasonable link between design and manufacturing for developing better CAAPP(Computer-Aided Assembly Process Planning) systems.

• International Journal of Internet, Broadcasting and Communication
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• v.9 no.2
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• pp.20-26
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• 2017

Process control is crucial in many industries, especially in semiconductor manufacturing. In such large-volume multistage manufacturing systems, a product has to go through a very large number of processing steps with reentrant) before being completed. This manufacturing system has many machines of different types for processing a high mix of products. Each process step has specific quality standards and most of them have nonlinear dynamics due to physical and/or chemical reactions. Moreover, many of the processing steps suffer from drift or disturbance. To assure high stability and yield, on-line quality monitoring of the wafers is required. In this paper we develop a real-time fault detection system on semiconductor manufacturing process. Proposed system is superior to other incremental fault detection system and shows similar performance compared to batch way.

• Korean Journal of Computational Design and Engineering
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• v.1 no.3
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• pp.203-214
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• 1996

An information sharing system, namely World Design View, is developed for browsing product design data on the World Wide Web environment. For the last few years information sharing has been rapidly emerging as an important research issue in the areas of concurrent engineering, product data management, virtual manufacturing, and so on. Since we are mainly concerned with product development, the key information that needs be communicated and shared is product data. The developed system puts the major advantages of STEP, OODB, and VRML together. The STEP standard provides a consistent data exchange format and application interfaces among different CAD/CAM systems. OODB is efficient and effective in dealing with complex data structures often found in engineering applications. Virtual worlds for 3-D product models can be created by VRML which is networked via the global Internet and hyperlinked with WWW. The World Design View system can support for members of virtual design teams, possibly distributed all over the world, to share 3-D shape information quickly and easily.

• Journal of Korean Institute of Industrial Engineers
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• v.23 no.3
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• pp.597-608
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• 1997

Life cycle product data is very important yet difficult to handle for manufacturing companies. Shoring and exchanging product data over world-wide-web is a part of key technology to implement PDM or CALS. STEP is widely accepted as a standard to represent the life-cycle product model data. Described in this paper is a web browser plug-in that can graphically display and explore product data represented by STEP over internet. By the use of the plug-in (named "npSTEP"), a product model data stored in STEP format on a web server can be displayed on a commonly used web client (browser), such as Netscape navigator, without any format conversion process. Furthermore one can explore the components or attributes of the product model data in hierarchical manner.