• Journal of the Korean Ceramic Society
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• v.44 no.4 s.299
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• pp.235-239
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• 2007

For the pressure compaction process of the ceramic powder, the density distribution is very important for the uniform shrinkages at the sintered body. In this paper, we fabricated alumina green body using compaction process and simulated about same condition. Then comparison of simulation and experimental result confirmed that accuracy of simulation. On the average density of top and lower part was each $2.41g/cm^3,\;2.27g/cm^3$ and deviation at final step was calculated with 0.06 in simulation. Also, experiments show that total density of top and lower part was each $2.59g/cm^3,\;2.36g/cm^3$, and deviation was 0.09. Conclusion, that was not a difference to the simulation and experimental result. The application using the finite element simulation method is possible optimization of the compressing process, predict generated part of cracks and there is a possibility of getting result of more fast, more accurate then existing experience method.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.10
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• pp.40-44
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• 2010

Laser drilling is an enabling technology for Through Silicon Via (TSV) interconnect applications. Recent advances in picoseconds laser drilling of blind, micron sized vias in silicon is presented here highlighting some of the attractive features of this approach such as excellent sidewall quality. In this study, we dealt with comparison of heat affection around drilled hole between a picosecond laser and a nanosecond laser process under the UV wavelength. Points which special attention should be paid are that picosecond laser process lowered experimentally recast layer, surface debris and micro-crack around hole in comparison with nanosecond laser process. These finding suggests that laser TSV process has possibility to drill under $10{\mu}m$ via. Finally, the laser drilling platform was constructed successfully.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.9
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• pp.74-81
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• 2002

Recently tube hydroforming has been widely applied to the automotive industries due to its several advantages over conventional methods. In this paper, attention is paid to comparison of an implicit and an explicit finite element method widely used for numerical simulation of a hydroforming process. For an explicit FEM, a huge amount of computational time is required because of the very small time increment to solve a quasi-static problem. Hence, when an explicit FEM is used fDr a hydroforming process, it is general to convert the real problem to a virtual problem with a different processing time and mass density by appropriate scaling factor. However it is difficult to figure out how large the scaling should be adopted enough to ignore the dynamic effects and maintain the desired accuracy. In this paper, the comparison of the results obtained from both methods focus on the accuracy of the predicted geometrical shape and the stress with various scaling factors which are applied to analyze hydroforming process of an automobile lower arm.

• Journal of the Korean Society of Earth Science Education
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• v.2 no.1
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• pp.55-61
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• 2009

This study was designed to explore problem solving process to earth science area by elementary science gifted children, which compared and analyzed the questionnaires and problem solving to earth science area by gifted Science education center, Seoul National University Of Education, The analyzed results showed difference by gender that in the science study level at the time of entrance to the gifted Science education center, male students was the highest in the middle school as 37.5%, and female students in the elementary 6th grade as 61.5%. And male students were investigated to do more precedent study than female students. Secondly, in the problem solving process of earth science related problems, males made most use of problem solving process area(30.3%), and females symbolizing (27.5%) area. Thirdly, comparison of reasoning technology in problem solving process by gender indicated that both sexes made the most use of analytical reasoning (male 62.0%, female 53.6%) to solve problems.

• Journal of the Semiconductor & Display Technology
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• v.20 no.3
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• pp.32-38
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• 2021

We developed an inductively coupled plasma (ICP) etcher for GaN etching using a parallel plasma electrode source with a multifunctional chuck matched to it in order for the low power consumption and low process cost in comparison with the conventional ICP system with a helical-type plasma electrode source. The optimization process condition using it for the micro light-emitting diode (µ-LED) chip fabrication was established, which is an ICP RF power of 300 W, a chuck power of 200 W, a BCl₃/Cl₂ gas ratio of 3:2. Under this condition, the mesa structure with the etch depth over 1 ㎛ and the etch angle over 75° and also with no etching residue was obtained for the µ-LED chip. The developed ICP showed the improved values on the process pressure, the etch selectivity, the etch depth uniformity, the etch angle profile and the substrate temperature uniformity in comparison with the commercial ICP. The µ-LED chip fabricated using the developed ICP showed the similar or improved characteristics in the L-I-V measurements compared with the one fabricated using the conventional ICP method

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.207-208
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• 2023

The procedure of predicting the construction cost and selecting the best alternative is performed based on comparative review of each building case. In the case of office building, it is required continuously until design is complete, since the owner requirements are various and likely to change during the design process compared to a standardized apartment. However, since the comparison work for each alternative in practice uses only the unit construction cost, there is no correlation between the alternative and the final result, and it is difficult to quantitatively determine the effect of the determined design factor on the total construction cost. It is needed that a means to support the generation of design alternatives using similar building cases during the design phase. This paper proposes a BIM-based data replacing process to support creating and comparison of design alternatives of internal finishing for office building. When design alternatives are created through the proposed process, it is possible to compare several similar cases with current project under equivalent design circumstance. Because only some finishing properties are replaced while maintaining the shape information such as the length, height, and base constraint of the object to be replaced.

• JSTS:Journal of Semiconductor Technology and Science
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• v.11 no.1
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• pp.1-5
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• 2011

To enter next process control, numerous approaches, including run-to-run (R2R) process control and fault detection and classification (FDC) have been suggested in semiconductor manufacturing industry as a facilitation of advanced process control. This paper introduces a novel type of optical plasma process monitoring system, called plasma eyes chromatic system (PECSTM) and presents its potential for the purpose of fault detection. Qualitatively comparison of optically acquired signal levels vs. process parameter modifications are successfully demonstrated, and we expect that PECSTM signal can be a useful indication of onset of process change in real-time for advanced process control (APC).

• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.98-105
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• 1999

As the IC(Integrated Circuit) has been densified and complicated, it is required to thorough process control to improve yield. Experts, for this purpose, focused on the process analysis automation, which is came from the strict data management in semiconductor manufacturing. In this paper, we presents the process analysis system that can analyze causes, for a output after processes. Also, the plasma etching process that highly affects yield among semiconductor process is modeled to predict a output before the process. To approach this problem, we use adaptively trained neural networks that exhibit superior accuracy over statistical techniques. And in comparison with methods in other paper, a method that history of trend for input data is considered is shown to offer advantage in both learning and prediction capability. This research regards CD(Critical Dimension) that is considerable in high integrated circuit as output variable of the prediction model.

• Analytical Science and Technology
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• v.33 no.4
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• pp.197-207
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• 2020

The current comparison methods with scoring systems that are used to compare visualized latent fingerprints (LF) have disadvantages. Evaluators using these methods are prone to make errors and fail to discriminate LFs correctly to notice the differences among those LFs. Therefore, a comparative and quantitative evaluation method that is capable of obtaining more objective and quantitative results is needed. Densitometric image analysis (DIA) is used in other fields as a reliable semi-quantitative comparison method. To apply DIA to LFs, the potential variables that can occur during the DIA process were tested. The visualized ridges of LFs can be compared using the concentration of dots against the background to make it possible to analyze the ridges with DIA. The variables that can be present during the DIA process include the thickness of the analysis line, the number of ridges to be taken, the number of divided zones within each of the fingerprints, and the angles of the analysis line against the ridge lines that were selected. From the analysis of the inked fingerprints and circular lines that are similar to fingerprints, the angle of the analysis lines with the ridge line was the most significant variable. The preliminary test result was applied to the comparison of LFs that were developed with the powder method and then compared with the AFIS analysis. A similar trend was found, and a more detailed and semi-quantitative comparison of the visualized LFs was possible. In the future, it is necessary to check the evaluative ability of the DIA method by analyzing the visualized LFs with other various development methods. However, DIA is currently an option that can be used as an objective comparative evaluation method during fingerprint studies with supplementary role.

• Journal of Environmental Science International
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• v.15 no.6
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• pp.571-577
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• 2006

This study make a comparison between the phosphorus removal performance of FNR(Ferrous Nutrient Removal) process and A/O process by the laboratory experiments. For simultaneous removal of phosphorus, iron electrolysis was combined with oxic tank. Iron precipitation reactor on the electrochemical behaviors of phosphorus in the iron bed. The phosphorus removal in FNR process was more than A/O process. Iron salts produced by iron electrolysis might help to remove COD and nitrogen. And the demanded longer SRT is the more removes the removes COD, nitrogen, and phosphorus. Also, FNR process of sludge quantity more reduce than A/O process to input cohesive agents.