• Journal of the Microelectronics and Packaging Society
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• v.21 no.4
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• pp.117-123
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• 2014

Cu through-vias, which can be used as thermal vias or vertical interconnects, were formed using bottom-up electrodeposition filling as well as top-down electrodeposition filling into open via-holes and their microstructures were observed. Solid Cu through-vias without voids could be successfully formed by bottom-up filling as well as top-down filling with direct-current electrodeposition. While chemical-mechanical polishing (CMP) to remove the overplated Cu layer was needed on both top and bottom surfaces of the specimen processed by top-down filling method, the bottomup process has an advantage that such CMP was necessary only on the top surface of the sample.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.4
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• pp.233-240
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• 2019

Open-hole tensile tests are usually performed to measure the tensile strengths of composites as they are an essential parameter for designing composite structures. However, correctly modeling the tensile test is extremely challenging as it involves various damages such as fiber and matrix damage, delamination, and debonding damage between the fiber and matrix. Therefore, a progressive damage model was developed in this study to estimate the in-plane failure and delamination between the fiber and matrix. The Hashin damage model and cohesive zone approach were used to model ply and delamination failures. The results of the present model were compared with previously published experimental and numerical findings. It was observed that neglecting delamination during finite element analysis led to overestimation of tensile strength.

• 한국전산유체공학회:학술대회논문집
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• 2004.03a
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• pp.208-213
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• 2004

The HANARO, multi-purpose research reactor, 30 MWth open-tank-in- pool type, is under normal operation since it reached the initial critical in February 1995. The HANARO is planning to produce a fission moly-99 of radio isotopes, a mother nuclide of Tc-99m, a medical isotope and is under developing a target handling tool for loading and unloading it in a circular flow tube (OR-5). A guide tube is extended from the reactor core to the top of the reactor chimney for easily un/loading a target under the reactor normal operation. But active coolant through the core can be quickly raised up to the top of the chimney through the guide tube by jet flow. This paper is described an analytical analysis to calculate the hole size of a orifice inserted in the circular irradiation hole and to study the flow characteristics through the guide tube under reactor normal operation and loading the target. As results, the results show that the hole size of orifice was 31 mm of the inner diameter to suppress the guide tube jet flow and the coolant safely cooled the target of fission moly after inserting the orifice to the flow tube.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.379-379
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• 2010

Recent technical advances in OLEDs (organic light emitting devices) requires more and more the improvement in low operation voltage, long lifetime, and high luminance efficiency. Inverted top emission OLEDs (ITOLED) appeared to overcome these problems. This evolved to operate better luminance efficiency from conventional OLEDs. First, it has large open area so to be brighter than conventional OLEDs. Also easy integration is possible with Si-based driving circuits for active matrix OLED. But, a proper buffer layer for carrier injection is needed in order to get a good performance. The buffer layer protects underlying organic materials against destructive particles during the electrode deposition and improves their charge transport efficiency by reducing the charge injection barrier. Hexaazatriphenylene-hexacarbonitrile (HAT-CN), a discoid organic molecule, has been used successfully in tandem OLEDs due to its high workfunction more than 6.1 eV. And it has the lowest unoccupied molecular orbital (LUMO) level near to Fermi level. So it plays like a strong electron acceptor. In this experiment, we measured energy level alignment and hole current density on inverted OLED structures for hole injection. The normal film structure of Al/NPB/ITO showed bad characteristics while the HAT-CN insertion between Al and NPB greatly improved hole current density. The behavior can be explained by charge generation at the HAT-CN/NPB interface and gap state formation at Al/HAT-CN interface, respectively. This result indicates that a proper organic buffer layer can be successfully utilized to enhance hole injection efficiency even with low work function Al anode.

• Composites Research
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• v.16 no.4
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• pp.66-73
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• 2003

The importance of understanding the response of structural composites to impact and CAI cannot be overstated to develop analytical models for impact damage and CAI strength predictions. This paper presents experimental findings observed from quasi-static lateral load tests, low velocity impact tests. CAI strength and open hole compressive strength tests using 3 mm thick composite plates($[45/-45/0/90]_{3s}$- IM7/8552). The conclusion is drawn that damage areas for both quasi-static lateral load and impact tests are similar and the curves of several drop weight impacts with varying energy levels(between 5.4 J and 18.7 J) follow the static curve well. In addition, at a given energy the peak force is in good agreement between the static and impact cases. It is identified that the failure behaviour of the specimens from the CAI strength tests was very similar to that observed in laminated plates with open holes under compression loading. The residual strengths art: in good agreement with the measured open hole compressive strengths. considering the impact damage site area, an equivalent hole. The experimental findings suggest that simple analytical models for the prediction of impact damage area and CAI strength can be developed on the basis of the failure mechanism observed from the experimental tests.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.1
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• pp.42-48
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• 2001

Over two decades, many researchers have performed studies on strength size effects in composite laminates under tensile and flexural loads. It is well known that there is a tendency for the strength of fibre-reinforced composites to decrease with increasing specimen size. Under compressive load, however, little work has been done on the effect of specimen size to failure strength. This is due to the fact that compressive testing of composite is very difficult. In this paper, the effect of the test specimen size on the compressive strength of composites containing open hole was considered using T300/924C, $>[45/-45/0/90]_{3S}$. For sizing test specimens, the in-plane scaling method is used i.e., the change of two- dimensional specimen area in specimen width and gauge length. The results clearly show that there is a hole size effect in the finite width plates. In addition, the specimens which have the same a/W(hole diameter/specimen width) exhibit a tendency of size effect. In contrast, test results of the unnotched specimens did not show a clear strength size effect.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.311-312
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• 2010

The fabricated photovoltaic cells based on PIN heterojunctions, in this study, have a structure of ITO/poly(3, 4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT:PSS)/donor/donor:C60(10nm)/C60(35nm)/2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline(8nm)/Al(100nm). The thicknesses of an active layer(donor:C60), an electron transport layer(C60), and hole/exciton blocking layer(BCP) were fixed in the organic photovoltaic cells. We investigated the performance characteristics of the PIN organic photovoltaic cells with copper phthalocyanine(CuPc), tetracene and pentacene as a hole transport layer. Discussion on the photovoltaic cells with CuPc, tetracene and pentacene as a hole transport layer is focussed on the dependency of the power conversion efficiency on the deposition rate and thickness of hole transport layer. The device performance characteristics are elucidated from open-circuit-voltage(Voc), short-circuit-current(Jsc), fill factor(FF), and power conversion efficiency($\eta$). As the deposition rate of donor is reduced, the power conversion efficiency is enhanced by increased short-circuit-current(Jsc). The CuPc-based PIN photovoltaic cell has the limited dependency of power conversion efficiency on the thickness of hole transport layer because of relatively short exciton diffusion length. The photovoltaic cell using tetracene as a hole transport layer, which has relatively long diffusion length, has low efficiency. The maximum power conversion efficiencies of CuPc, tetracene, and pentacene-based photovoltaic cells with optimized deposition rate and thickness of hole transport layer have been achieved to 1.63%, 1.33% and 2.15%, respectively. The photovoltaic cell using pentacene as a hole transport layer showed the highest efficiency because of dramatically enhanced Jsc due to long diffusion length and strong thickness dependence.

• Culinary science and hospitality research
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• v.13 no.1 s.32
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• pp.204-211
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• 2007

In order to develop a pot lid that would not overflow, three parts were created, each different in size. One cover (A") had a small hole (dia. 10 cm) for the vapor to escape (dia. about 2.5 mm). Another, cover A' had a medium-sized hole (dia. about 5 cm) for the vapor to escape. Cover A (dia. 300 mm, $120\;mm^H$) had a large hole (dia. 100 mm) for the vapor to escape. Because the new cover was partially open while soy paste solution cooking, it showed that it could not only prevent overflow, but also extend the burning approaching and salinity increase time, reducing both cooking time and the amount of energy necessary to cook.

• Journal of the Korea Safety Management & Science
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• v.6 no.2
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• pp.79-89
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• 2004

It is known that most people have a dominant eye, even though each of their two eyes in isolation may provide equal vision. In this study, 600 Korean male and female subjects aging from 11 to 78 were selected to investigate the various statistics about eye dominance( whether the left or right eye is dominant} in Korean and their employment characteristics of preferred eye in sighting diverse things. A simple sighting test was applied such that subjects are requested to aim a distance target through small hole in B4 sized paper with both eyes open. The dominant eye was determined by alternate occlusion: when viewing with the dominant eye into the hole is aligned with the target, whereas when viewing with the other eye into the hole appears offset to one side. The descriptive statistics showed that 83.7% and 16.3% were right and left eye dominant respectively. Moreover, various statistical analysis revealed that general tendency of eye dominance was varied by age, gender, hand dominance and visual acuity. It was thus found from these results that people sighting their eyes differently depending on the eye dominance when they sight things.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.1 s.232
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• pp.151-158
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• 2005

A characteristic of discharge for a foam spray nozzle with various parameters was investigated. The discharge patterns from a fire foam spray nozzle are important to evenly spray over a maximum possible floor area. Two parameters of a foam spray nozzle were chosen, and compared with those from the standard one. Also, in order to evaluate the performance of discharged foam agents used to protect structures from heat and fire damages, the thermal characteristics of fire-protection foams were experimentally investigated. A simple repeatable test for fire-protection foams subjected to fire radiation was developed. This test involves foam generation equipment, a fire source for heat generation, and data acquisition techniques. Results show that the bubble size of foam is increased by large inside diameter of orifice or closed air hole, but phenomenon of discharge angle and expansion ratio is opposite. For the case of the open air hole, liquid film of a circular cone discharges with formation, growth, split and fine grain. In case of the closed air hole, a pillar of foam solution discharges with that. Though the temperature gradient in the foam increases with increased foam expansion ratio. it is not change with increased intensity of heat flux.