• Journal of Sensor Science and Technology
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• v.31 no.1
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• pp.36-40
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• 2022

High-power devices, such as LEDs and radars, inevitably generate a large amount of heat, which is the main cause of shortening lifespan, deterioration in performance, and failure of electronic devices. The embedded IC process can be a solution; however, when applied to large-area substrates (larger than 8 in), there is a limit owing to the difficulty in the process after wafer thinning. In this study, an 8-in wafer-level high-power electronic package based on the embedded IC process was implemented with temporary bonding and debonding technology using double-sided thermal release tape. Good heat-dissipation characteristics were demonstrated both theoretically and experimentally. These findings will advance the commercialization of high-power electronic packaging.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.59.3-59.3
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• 2019

The last two decades have seen an immense growth in our understanding of the physics of the birth and evolution of our Universe. However there are still many unanswered questions, such as: what is the nature of the dark energy, which drives the acceleration of the expansion of the Universe? Is the acceleration driven by a cosmological constant, some dynamical dark energy, or a modification of the gravitational force law on large scales? The next generation of radio observatories will conduct large area radio continuum and HI intensity mapping surveys, and so will make possible new and complimentary tests of these fundamental questions. In this talk I present the design of these next generation of surveys, current forecasts for the effectiveness of these cosmological probes, and results from precursor experiments.

• Journal of Families and Better Life
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• v.19 no.1
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• pp.95-110
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• 2001

Recently a number of large discount store and those of its users was increasing. The purpose of this study is to investigate the tendency of impulse buying and analyzes factors which influence impulse buying. The data had been collected from questionaries with 474 consumers who visit large discount store. The major statistical methods used for data analysis are frequency, percentile, mean, t-test, multiple regression analysis, one-way ANOVA, and Duncans multiple range test utilizing SPSS Win pc+program. The results of this study are as follows : 1. The four different kind of impulse buying is measured. The overall level of impulse buying is 2.76. Suggestion impulse buying(M=3.19) is the highest, and the lowest is pure impulse buying(M=2.66). 2. In the area of demographic variables is significantly different in the age of twenties and thirties(p<.05). A visit frequency and membership. In the area of in-store variables is significantly different by all factors at impulse buying except waiting time. Especially, point-of-purchase(POP) advertisement and discount sale are very important variables. A visit frequency and membership are significantly different in the area of consumer-related variables. 3. Waiting time, a visit frequency, a POP advertisement, and a discount sale have the positive effects on overall impulse buying. Pure impulse buying is influenced by shopping list, POP advertisement and a stores atmospher. Buying companion, membership, kind of store and waiting time have the effect on reminder impulse buying. Suggestion impulse buying is influenced by school career, shopping list and POP advertisement. Planned impulse buying is influenced by sex, POP advertisement, buying companion and discount sale.

• Korean Journal of Computational Design and Engineering
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• v.21 no.1
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• pp.90-98
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• 2016

When ships and offshore plants are flooded or the floating crane is equipped with a heavy object, these floating structures are excessively inclined. In this case, immersion, heel, and trim affecting the hydrostatic restoration performance are very large and are coupled each other. In this paper, in order to calculate a static equilibrium position of floating structures with excessive inclination, the nonlinear governing equations were constructed by sequential linearization. In the governing equation, the immersion, heel, and trim are fully coupled, and the equations are represented using a plane area, a primary moment, and a moment of inertia of the water plane area. Therefore, it is possible to calculate the additional factor related the water plane area for estimating stability. Position and orientation of the floating structure are obtained by iterative calculation. The calculated results are compared with the previous studies in the aspect to the performance and the accuracy.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1522-1526
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• 2005

In this study, the fabrication of large area silicon mirror is accomplished by anisotropic etching using MEMS for implementation of integrated optical pickup and the process condition is also established for improving the mirror surface roughness. Until now, few results have been reported about the production of highly stepped $9.74^{\circ}$ off-axis-cut silicon wafer using wet etching. In addition rough surface of the mirror is achieved in case of long etching time. Hence a novel method called magnetorheolocal finishing is introduced to enhancing the surface quality of the mirror plane. Finally, areal peak to valley surface roughness of mirror plane is reduced about 100nm in large area of $mm^2$ and it is applicable to optical pickup using infrared wavelength.

• 보존과학연구
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• s.26
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• pp.57-75
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• 2005

The burial custom in the Youngsan river area was to build a jar-coffin and lay the body in state, however the methods in building and moulding the massive jar, as well as in which kiln it was made has not been examined precisely. Thus, this research not only investigates previous results related to the manufacturing methods of massive jar-coffins, but also examines samples that were excavated and collected. The clay used to produce jar-coffin consists a large portion of unglazed qualities, which was split-moulded from the bottom up to the mouth area. The interior was finished by applying water, whereas the exterior was decorated by regularly pasting or stamping in parallel with a lattice design. It can be presumed that the finished jar-coffin was not moved, but the ceiling and walls were built around it as a kiln, for the jar-coffin to be oxidized or to reduce the flame condition in a temperature approximately $700~1,200^{\circ}C$The results from the research, however, show limitations to exploit the exact manufacturing method, therefore there is a need for in-depth examinations: mineralogical investigation on a large amount of jar-coffin samples through a polarized light microscope; substance analysis using various equipments; speculation on the temperature in the place of production and the flame inside.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.123-127
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• 2007

Up sizing of dye-sensitized solar cell(DSC) is the important technology to bring about commercialization of DSC. Several studies to obtain a stable large area DSC have been investigated in overseas laboratories, but have been hardly done in our country. In this study, up sizing technology of dye sensitized solar cells(DSCs) was investigated. We investigated low dark current materials for the current collecting grid. From the result, a new DSC module with metal grid was designed, and fabricated. For a new interconnection, both working and counter electrodes are alternately coupled on 10[cm]$\times$7[cm] substrate. We have achieved 68% of fill factor and photoelectric conversion efficiency of around 2.6% as the best results of new designed DSC structure.

• Journal of Environmental Science International
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• v.22 no.10
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• pp.1337-1344
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• 2013

We examined urban heat island intensity in Seongseo, Dae gu, South Korea, where a large area of water is located within the suburb. We found a maximum urban heat island intensity of $4.2^{\circ}C$, which occurred around 7 PM in the summer season. Throughout the remainder of the year, we observed the largest heat island intensity levels during late night hours. In contrast, the winter season displayed the smallest values for heat island intensity. Our results conflicted with heat island intensity values for cities where suburbs did not contain water areas. Generally, cities with suburbs lacking water displayed the largest heat island intensity levels before sunrise in the winter season. We also observed negative urban heat island intensity levels at midday in all seasons except for the summer, which is also in contrast with studies examining suburbs lacking water areas. The heat island intensity value observed in this study ($4.2^{\circ}C$) was relatively large and fell between the averages for, Asia and Europe according to the relationship between urban population and heat island intensity.

• Archives of Plastic Surgery
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• v.43 no.5
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• pp.446-450
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• 2016

Background Perineal defects are commonly encountered during the treatment of conditions such as malignancy, infectious disease, and trauma. Covering large defects in the perineal area is challenging due to its complicated anatomy and the need for functional preservation. Methods Fourteen patients who underwent reconstructive surgery with multiple perforator flaps for defects >$100cm^2$ in the perineal area were included in this retrospective cohort study. Characteristics of the perforator flap operation and postoperative outcomes were reviewed. Results Reconstruction was performed using 2 perforator flaps for 13 patients and 3 perforator flaps for 1 patient. Internal pudendal artery perforator flaps were mainly used for covering the defects. The average defect size was $176.3{\pm}61.8cm^2$ and the average size of each flap was $95.7{\pm}31.9cm^2$. Six patients had minor complications, such as wound dehiscence and partial necrosis of the flap margin, which were corrected with simple revision procedures. Conclusions Multiple perforator flaps can be used to achieve successful reconstructions of large perineal defects that are difficult to reconstruct with other coverage methods.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.73-73
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• 1999

A large area negative metal ion beam source is developed. Kinetic ion beam of the incident metal ions yields a whole nucleation and growth phenomena compared to the conventional thin film deposition processes. At the initial deposition step one can engineer the surface and interface by tuning the energy of the incident metal ion beams. Smoothness and shallow implantation can be tailored according to the desired application process. Surface chemistry and nucleation process is also controlled by the energy of the direct metal ion beams. Each individual metal ion beams with specific energy undergoes super-thermodynamic reactions and nucleation. degree of formation of tetrahedral Sp3 carbon films and beta-carbon nitride directly depends on the energy of the ion beams. Grain size and formation of polycrystalline Si, at temperatures lower than 500deg. C is obtained and controlled by the energy of the incident Si-ion beams. The large area metal ion source combines the advantages of those magnetron sputter and SKIONs prior cesium activated metal ion source. The ion beam source produces uniform amorphous diamond films over 6 diameter. The films are now investigated for applications such as field emission display emitter materials, protective coatings for computer hard disk and head, and other protective optical coatings. The performance of the ion beam source and recent applications will be presented.