• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.9
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• pp.1277-1289
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• 1998

The objective of the present study is to investigate experimentally the mean flow characteristics of the three-dimensional turbulent boundary layer over a rotating disk with an impinging jet at the center of the disk, which may be regarded as one of the simplest models for the flow in turbomachinery. A relatively strong radial outflow (crossflow) generated from the impinging jet is added to the radial outflow (crossflow) induced by the centrifugal force in order to create the three-dimensional boundary layer. A new calibration technique has been introduced to determine the velocity direction and magnitude using an I-wire probe, where the uncertainties are ${\pm}1.5^{\circ}$ and ${\pm}0.35\;m/s$, respectively, in the laminar boundary layer region, compared with the known exact solutions. The flow in the tangential direction is of similar type to that associated with a favorable pressure gradient, considering that no wake region appears in wall coordinate velocity profiles and the Clauser shape factor is between 4.0 and 5.3. The flow angle is significantly changed by the crossflow generated by the impinging jet.

• Journal of the Korean Ceramic Society
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• v.46 no.3
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• pp.313-316
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• 2009

A zinc borosilicate glass having a low softening temperature of $490^{\circ}C$ has been investigated as a protective layer for Ag patterns against chemical reactions with a $I^-/I_3^-$ electrolyte in dye-sensitized solar cells (DSSCs). A thick glass layer was prepared by the typical screen printing and firing processes to obtain a final thickness of ${\sim}5{\mu}m$. The chemical leaching performance of the glass layer in the electrolyte revealed that the reactive Ag pattern can be significantly protected by utilizing the low softening protective layer. The electrical resistance of the FTO-coated glass substrate was effectively maintained at a low value of ${\sim}27{\Omega}$ as long as the glass layer was well densified at a sufficiently high temperature of ${\sim}520^{\circ}C$. The transmittance of the layer was near 60%, depending on the firing temperature of the glass layer.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.53.2-53.2
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• 2011

Dye-sensitized solar cells(DSSCs) have been recognized as an alternative to the conventional p-n junction solar cells because of their simple fabrication process, low production cost, and transparency. A typical DSSC consists of a transparent conductive oxide (TCO) electrode, a dye-sensitized oxide semiconductor nanoparticle layer, liquid redox electrolyte, and a Pt-counter electrode. In dye-sensitized solar cells, charge recombination processes at interfaces between coducting glass, $TiO_2$, dye, and electrolyte play an important role in limiting the photon-to-electron conversion efficiency. A layer of ZTO thin film less than ~200nm in thickness, as a blocking layer, was deposited by DC magnetron sputtering method directly onto the anode electrode to be isolated from the electrolyte in dye-sensitized solar cells(DSCs). This is to prevent the electrons from back-transferring from the electrode to the electrolyte ($I^-/I_3^-$). The presented DSCs were fabricated with working electrode of Ga-doped ZnO glass coated with blocking ZTO layer, dye-attached nanoporous $TiO_2$ layer, gel electrolyte and counter electrode of Pt-deposited GZO glass. The effects of blocking layer were studied with respect to impedance and conversion efficiency of the cells.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.213-217
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• 2009

Underground structures are built into concrete like a architecture and public works. Concrete has watertightness as such, But buildings are leaking from the cracks. Recently, construction method do a lot of close construction in the downtown area. So architects are using the method for the outer layer of a two-layer wall to save spaces. They have been using Top-down method and waterproof agent method and others to outer layer of a two-layer wall method. But, There are many leakage in underground structure from lack on requirements performance of materials. Therefore, I hope to test the outside Waterproof Method of Ground using Wire-mesh and Non-hardening Viscosity Waterproof. In addition to, I wish to apply as outside waterproof method for the section for the outer layer of a two-layer wall in underground structure.

• Proceedings of the Korean Magnestics Society Conference
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• 2004.12a
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• pp.200-201
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• 2004

The $H_{EB}$ was investigated for exchange coupling $20\;{\AA}\;Fe/x\;{\AA}\;NiO\;(type-I samples)$, $20\;{\AA}\;Fe/x\;{\AA}$ nonmagnetic layer $(MgO, Ag, Cu)/(500-x{\AA})$ NiO (type-II smaples). In type-I samples, the $H_{EB}$ is long-range coupling when looking from the point of view of the AFM. The $H_{EB}$ consistent with a generalized Meiklejohn-Bean approach. The critical thickness, which $H_{EB}$ is observed, is $130\;{\AA}$. In type-II samples, MgO layer more decouples the thin interfacial NiO from bottom NiO than other nonmagnetic layer. Nd the decoupling of Ag smallest. This means that the Ag layer has strong coupling the thin interfacial NiO with bottom NiO.

• Progress in Superconductivity and Cryogenics
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• v.19 no.4
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• pp.26-30
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• 2017

The promising characteristics of 2G high-temperature superconductor (HTS) coated conductor (CC) tapes have made it possible to apply to various electrical device applications. In this study, the mechanical and electromechanical properties of Sn-Cu double layer stabilized GdBCO CC tapes have been characterized. The stress and strain tolerances of $I_c$ in GdBCO CC tapes adopting stainless steel substrate were evaluated using $I_c$-strain measurement at 77 K under both uniaxial tension and monotonic bending conditions. The results were compared to the conventional single Cu layer stabilized CC tape. As a result, the Sn-Cu double layer stabilized GdBCO CC tapes showed somehow lower or comparable electromechanical properties as compared to the Cu stabilized CC tape ones.

• Journal of Sensor Science and Technology
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• v.20 no.4
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• pp.260-265
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• 2011

The silicon vertical hall devices are fabricated using a modified bipolar process. It consists of the thin p-layer at Si-$SiO_2$, interface and n-epi layer without $n^+$buried layer to improve the sensitivity and influence of interface effects. Experimental samples are a sensor type I with and type H without p+isolation dam adjacent to the center current electrode. The experimental results for both type show a more high current-related sensitivity than the former's vertical hall devices. The sensitivity of type H and type I are about 150 V/AT and 340 V/AT, respectively. This sensor's behavior can be explained by the similar J-FET model.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.10a
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• pp.68-73
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• 1993

The geometrical initial imperfection is generally described that a dome digeresses from ideal shape. In actual domes the mode and amplitude for initial imperfection appear variously and affect buckling-strength sensitively. This study investigates the buckling characteristics of single-layer latticed domes with triangular network subjected to initial imperfection. Additionally, this study is to get the data that are to formulate the general equation taking initial imperfection into consideration.

• Transactions on Electrical and Electronic Materials
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• v.4 no.3
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• pp.10-14
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• 2003

In this paper, we have introduced the x-ray detector built with a CsI:Na scintillation layer deposited on amorphous selenium. To determine the thickness of the CsI:Na layer, we have estimated the transmission spectra and the absorption of continuous x-rays in diagnostic range by using computer simulation (MCNP 4C). A x-ray detector with 65 ${\mu}m$-CsI:Na/30 ${\mu}m$-Se layer has been fabricated by a thermal evaporation technique. SEM and PL measurements have been performed. The dark current and x-ray sensitivity of the fabricated detector has been compared with that of the conventional a-Se detector with 100 ${\mu}m$ thickness. Experimental results show that both detectors exhibit a similar dark current, which was of a low value below $400 pA/cm^2$ at 10 V/${\mu}m$. However, the CsI:Na-Se detector indicates high x-ray sensitivity, roughly 1.3 times that of a conventional a-Se detector. Furthermore, a CsI:Na-Se detector with an aluminium reflective layer shows a 1.8 times higher x-ray sensitivity than an a-Se detector. The hybrid type detector proposed in this work exhibits a low dark current and high x-ray sensitivity, and, in particular, excellent linearity to the x-ray exposure dose.

• Journal of Veterinary Clinics
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• v.18 no.2
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• pp.124-132
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• 2001

The purpose of this study is to know whether single layer continuous connell suture is an acceptable alternative to simple interrupted approximating suture for end-to-end intestinal anastomosis in dogs. Fourteen mixed-breed dogs weighing 2 to 5 kg were allotted to group treated with simple interrupted approximating suture (Group I) and group treated with single layer continuous Connell suture (Group II), each of 7 dogs. All dogs in each suture pattern were compared with time for total operation ad suture elapsed for intestines to anastomose, clinical signs, changing of pre-and postoperative luminal size, status of feces, adhesion at anastomotic site for 14 days after operation. Time for total operation and suture time for intestinal anastomosis were none significant between Group I and Group II, although those in Group II was about 3 minutes shorter than those in Group I, respectively. Group I spent average 47.08${\pm}$11.10 minutes on total operation, 20.97${\pm}$5.54 minutes on suture time for intestinal anastomosis and Group II spent average 44.74${\pm}$7.77 minutes, 17.73${\pm}$3.05 minutes, respectively. All dogs were no special differences in vitality, vomiting, appetite between Group I and Group II for 14 days after operation. All dogs, except one dog in Group I, had showed normal vitality and appetite since 6~8 days after operation. Initial return of fecal passage showed in all dogs before 6 days after operation and thereafter most dogs showed normal feces. According to results, it was thought that all dogs with normal vitality and appetite before 8 days had showed good prognosis. There were no changes of intestinal luminal size in 2 dogs performed Group In and one dog performed Group II between at operation and 14 days after operation. Narrowing rate of intestinal lumen in Group I was average 9.3% of the normal diameter, whereas in Group II, 9.5% of normal diameter. In complications after operation, only one dog in Group I showed intestinal intussusception but the others didn't. Length of adhesion was measured between intestinal anastomotic site and omental graft. Length of adhesion in dogs performed Group II was mostly shorter than that of Group I. Adhesion with proximate intestines occurred in five dogs, which consisted of 3 dogs performed Group I and 2 dogs performed Group II. Concurrently, they had a great length of adhesion between anastomotic site and omental graft. There were no great differences between Group I and Group II about speed of operation, clinical signs, complications such as leakage and stricture. And all dogs performed intestinal anastomosis showed good clinical condition and prognosis. In conclusion, Single layer continuous Connell suture can safely perform an intestinal anastomosis and be an alternative of simple interrupted approximating suture in aspect of speed clinically.