• Journal of the Semiconductor & Display Technology
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• v.22 no.3
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• pp.119-124
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• 2023

In this study, experimental approach of the measurement of condensation and evaporation heat transfer coefficients is discussed for mixed refrigerants using in the ultra low-temperature cooling system for semiconductor etching process. An experimental apparatus was described performing the condensation and evaporation heat transfer measurements for mixed refrigerants. The mixed refrigerant used in this study was composed of the optimal mixture determined in previous research, with a composition of Ar:R14:R23:R218 = 0.15:0.4:0.15:0.3. The experiments were conducted over a temperature range from -82℃ to 15℃ and at pressures ranging from 18.5 bar to 5 bar. The convection heat transfer coefficients of the mixed refrigerant were measured at flow rates corresponding to actual operating conditions. The condensation heat transfer coefficient ranged from approximately 0.7 to 0.9 kW/m2K, while the evaporation heat transfer coefficient ranged from 1.0 to 1.7 kW/m2K. The detailed discussion of the experimental methods, procedures, and results were described in this paper.

• International conference on construction engineering and project management
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• 2024.07a
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• pp.41-48
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• 2024

The construction industry is a significant contributor to carbon emissions, with its life cycle emissions posing significant environmental challenges. Despite its increasing importance, embodied carbon (EC) generated from the construction process is often ignored. Modular construction (MC), characterized by a combination of off-site manufacturing and on-site assembly, has been recognized for its potential to contribute to environmental benefits. However, there is still a lack of systematic explanation of urban high-rise MC. This study aims to identify whether and to what extent high-rise MC can achieve EC reductions and lay the foundation for effective carbon reductuons in the construction industry. To achieve this, the study develops a multi-level EC measurement framework for assessing EC during the construction process, using a real case to quantify the EC and determine carbon reduction performance. The innovation is a more comprehensive understanding of the boundaries of EC, as MC includes the amount of superstructure work and decoration integration. The results show that although the MC will increase EC from the transportation stage due to heavier modules, it achieves a net reduction in total EC by reducing on-site machinery energy consumption and waste rates. In conclusion, this study contributes to a better understanding of the EC emissions associated with high-rise MC, offering a valuable measurement framework for global regions evaluating the EC impacts of high-rise MC in similar contexts.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.12
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• pp.823-828
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• 2013

In this paper, it will improve in quality to adapt a right test process which is formalized from certification of TMMi Level. To do this, we suggest correlative relation through analyzing associations between TMMi and TPI next based on the previous research[10], which provides the guideline for enhancing test process level with measuring Test maturity model. Also schematize test maturity measurement through refining and improving the previous test maturity correlation metrics[6,8,9]. As one example with limited level, it shows the guideline to improve test process of one testing organization through improved correlation metrics with TMMi and TPI next.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.126-126
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• 2009

Noninvasive plasma diagnostic technique is introduced to analyze and characterize HICP (Helmholtz Inductively Coupled Plasma) source during the plasma etching process. The HICP reactor generates plasma mainly through RF source power at 13.56MHz RF power and RF bias power of 12.56MHz is applied to the cathode to independently control ion density and ion energy. For noninvasive sensors, the RF sensor and the OES (Optical emission spectroscopy) were employed since it is possible to obtain both physical and chemical properties of the reactor with plasma etching. The plasma impedance and optical spectra were observed while altering process parameters such as pressure, gas flow, source and bias power during the poly silicon etching process. In this experiment, we have found that data measured from these noninvasive sensors can be correlated to etch results. In this paper, we discuss the relationship between process parameters and the measurement data from RF sensor and OES such as plasma impedance and optical spectra and using these relationships to analyze and characterize H-ICP source.

• Journal of Korean Elementary Science Education
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• v.31 no.2
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• pp.146-153
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• 2012

The purpose of this study were to know the effects of making science newspaper activity on the science inquiry process ability of elementary school students and to analyse the writing context about their articles. The 33 sixth grader were participated in this program and they made 3 or 4 make a group, 9 groups made their own science newspaper. The results are as follow: first, there were statistically significantly differences(p<.01) on the basic science inquiry process abilities especially measurement and reasoning on making science newspaper activity. But there were no significantly differences on the integrative science inquiry process abilities; second, according to their articles on science newspaper, in personal context, they used many terms such as ecosystem, producer, consumer, decomposer, balance, but it was not personalized. And in social context, They pointed the cause and solution for the pollution and destruction in ecosystem, but it was superficial. Lastly in physical context, They used well their science concepts from class and format in newspaper in making science newspaper.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.536-539
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• 2002

The reverse engineering (RE) technology can quickly generate 3D point cloud data of an object by capturing the surface of a model using a 3D scanner. In the rapid prototyping (RP) technology, prototypes are rapidly produced from 3D CAD models in a layer-by-layer additive basis. In this paper, a physical human head shape is duplicated using a new RP process, the Transfer-type Variable Lamination Manufacturing process using expandable polystyrene foam sheet (VLM-ST), after the point cloud data of a human head shape measured from 3D SNX scanner are converted to STL file. From the duplicated human head shape, it has been shown that the VLM-ST process in connection with the 3D scanner is a fast and efficient process in that shapes with free surface, such as the human head shape, can be duplicated with ease. Considering the measurement time and the shape duplication time, the use of 3D SNX scanner and the VLM-ST process is expected to reduce the lead-time fur the development of new products in comparison with the other existing RE-RP connected manufacturing systems.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.8
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• pp.1173-1182
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• 2001

Recent noticeable advances of CNC machine tools have considerably improved productivity and precision in manufacturing processes. However, in the respect of productivity some defects still remain because selection of machining conditions entirely depends on the experiences of programmers. Usually, machining conditions such as feed rate and spindle speed have been selected conservatively by considering the worst cases, and it has brought the loss of machining efficiency. Thus, the improvement of cutting force controller has been done to regulate cutting force constantly and to maximize feedrate simultaneously in case that machining conditions change variously. In this study, sliding mode control with boundary layer is applied to milling process for cutting force regulation and in a commercial CNC machining center data transfer between PC and PMC (programmable machine controller) of CNC machine is done using a standard interface method. And in the cutting force measurement, an indirect cutting force measuring system using current signal of AC servo is adopted in order not to use high-priced equipment like tool dynamometer. The purpose of this study is to maximize the productivity in milling process, thus its results can be applied to cases such as rough cutting process.

• Korean Management Science Review
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• v.13 no.1
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• pp.135-156
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• 1996

The purpose of this paper is to study the links between manufacturing strategy and change programs of manufacturing firms in Korea. The nature of our analysis is more descriptive than normative or confirmative. First, we investigate the linkage between manufacturing strategy, manufacturing capability, change programs and performance measurement systems. Secondly, we intend to explore an empirical typology of manufacturing strategy and change programs. The initial findings of the study are as follows: Linkage between manufacturing strategy and change programs of manufacturing firms was not apparent. Flexibility as a strategic priority is positively related to the innovative change programs. There are two distinctive strategies of manufacturing firms in Korea, namely, quality strategy and balanced strategy. We identified three types of change programs, which are incremental change, administrative innovation, and process innovation. Incremental change group has represented low factor score in the change program dimensions. The firms in administrative innovation group mainly depend on information systems and business reengineering. Korean manufacturing firms seem to pursue process improvement by trying simultaneously incremental change in the process, managerial process improvement, and a little bit of innovative change. Performance variable utilization of the firms are not significantly different along with manufacturing strategies and change programs. We found, however, learning and improvement performance dimension is significantly related to flexibility variables. Process innovation group marked high score in usage of learning and improvement indices. The findings of this study seem to have various implications on realigning the manufacturing strategy, change programs, and performance systems in Korean firms.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1352-1355
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• 1996

The control of diamond turning is usually achieved through a laser-interferometer feedback of slide position. If the tool post is rigid and the material removal process is relatively static, then such a non-collocated position feedback control scheme may surface. However, as the accuracy requirement gets tighter and desired surface contours become more complex, the need for a direct tool-tip sensing becomes inevitable. The physical constraints of the machining process prohibit any reasonable implementation of a tool-tip motion measurement. It is proposed that the measured force normal to the face of the workpiece can be filtered through an appropriate admittance transfer function to result in the estimated depth of cut. This can be compared to the desired depth of cut to generate the adjustment control action in addition to position feedback control. In this work, the design methodology on the admittance model-based control with a conventional controller is presented. The recursive least-squares algorithm with forgetting factor is proposed to identify the parameters and update the cutting process in real time. The normal cutting forces are measured to identify the cutting dynamics in the real diamond turning process using the precision dynamometer. Based on the parameter estimation of cutting dynamics and the admittance model-based nanodynamic control scheme, simulation results are shown.

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.1
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• pp.27-32
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• 2003

Highly reproducible side-wall process for the fabrication of the fine gate length as small as 40nm was developed. This process was utilized to fabricate 40nm InGaAs HEMTs with the 65% strained channel. With the usage of the dual $SiO_2$ and $SiN_x$ dielectric layers and the proper selection of the etching gas, the final gate length (Lg) was insensitive to the process conditions such as the dielectric over-etching time. From the microwave measurement up to 40GHz, extrapolated fT and fmax as high as 371 and 345 GHz were obtained, respectively. We believe that the developed side-wall process would be directly applicable to finer gate fabrication, if the initial line length is lessened below the l00nm range.