• Journal of Surface Science and Engineering
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• v.32 no.3
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• pp.307-311
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• 1999

The well-crystalline hydroxyapatite($Ca_{10}(PO_4)_6(OH)_2$ ; HAp) layer having a biocompatibility was successfully coated onto titanium substrate using a radio-frequency magnetron sputtering, and effects of sputtering gas and the thickness of HAp film on a crystal growth of the HAp layers were investigated. The deposition rate of the layer sputtered with water-vapour gas was slower than that of the layer sputtered with argon gas. The results of X-ray diffraction demonstrated that the about $0.8\mu\textrm{m}$ thick HAp film under water-vapour gas was an amorphous phase, the about $1.2\mu\textrm{m}$ thick film was (100) plane-oriented HAp, and the about $1.5\mu\textrm{m}$ thick film was (001)plane-oriented HAp. FT-IR analysis proved that hydroxyl group of the layer sputtered with argon gas was defected, but that of the layer sputtered with water-vapour gas was not defected. From these results, it was favorable to use water-vapour gas on the HAp coatings onto metal surface.

• The KSFM Journal of Fluid Machinery
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• v.14 no.6
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• pp.35-44
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• 2011

Membrane filtration has become firmly established as a primary process for ensuring the purity, safety and efficiency of treatment of water or effluents. Several researches have been performed to develop and design membrane systems in order to increase the accuracy and performance of the processes. In this study, a lattice Boltzmann method for the cake layer has been developed using particle dynamics based on an immersed boundary method and the cake layer formation process on membrane has been numerically simulated. Case studies including various particle sizes were also performed for a microfiltration process. The growth rate of the cake layer thickness and the permeation flow rate along the membranes were predicted. The results of this study agreed well with that of previous experiments. Effects of various particle diameters on the membrane performance were studied. The cake layer of a large particle tended to be growing fast and the permeation flow going down rapidly at the beginning. The layer thickness of a small particle increased constantly and the flow rate was smaller than that of the large particle at the end of simulation time.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.2
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• pp.31-35
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• 2014

The thickness dependent electrical, structural, and optical properties of ZnO films grown by atomic layer deposition (ALD) at various growth temperatures were investigated. In order to deposit ZnO films, diethylzinc and deionized water were used as metal precursor and reactant, respectively. ALD process window was found at the growth temperature range from $150^{\circ}C$ to $250^{\circ}C$ with a growth rate of about $1.7{\AA}/cycle$. The electrical properties were studied by using van der Pauw method with Hall effect measurement. The structural and optical properties of ZnO films were analyzed by using X-ray diffraction, field emission scanning electron microscopy, and UV-visible spectrometry as a function of thickness values of ZnO films, which were selected by the lowest electrical resistivity. Finally, the figure of merit of ZnO films could be estimated as a function of the film thickness. As a result, this investigation of thickness dependent electrical, structural, and optical properties of ZnO films can provide proper information when applying to optoelectronic devices, such as organic light-emitting diodes and solar cells.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.313-315
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• 2006

Proper water management is important to achieve high performance and durability of Polymer electrolyte fuel cell (PEFC). Among various stack components, gas diffusion layer (GDL) is considered as a core part to determine the gas and water transportation in a cell. To optimize the water management, the changes of properties as well as basic properties of GDLs were investigated before and after clamping of colls. Thickness, electric conductivity, porosity, hydroppobicity etc. were characterized by the same criteria. The amount of residual water after cell operation also was compared by direct measuring of weight. Based on the amount of residual water the endurance on the freeze condition was evaluated.

• Restorative Dentistry and Endodontics
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• v.28 no.6
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• pp.498-503
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• 2003

The purpose of this study was to evaluate the rewetting effect of water-based primer on the air-dried dentin. In this in vitro study, freshly extracted non-caries human molars and three-step adhesive system(SBMP) were used. Freshly extracted non-caries human molars and three-step adhesive system(SBMP) were used. Flat occlusal dentin surface were prepared using low-speed diamond saw, Prepared teeth were randomly divided into three groups. Group 1.(W): etched(35% phosphoric acid for 15s) and blot-dried, Group 2.(5D): 5s air-dried, Group 3.(30D): 30s ail-dried, To obtain color contrast in CLSM observation, primer was mixed with rhodamine B and bonding resin was mixed with fluorescein. Microscopic sample of each group were obtained after longitudinal section. Morphological investigation of resin-dentin interface and thickness of hybrid layer measurement using CLSM were done. Microtensile bond strength for each specimen was measured. Specimen were observed under microscope to examine the failure patterns of interface between resin and dentin. The results of this study were as follows: 1. The results(mean) of Thickness of hybrid layer were W:19.67, 5D:20.9, 30D:10$\mu\textrm{m}$. Only 30D had statistically significant differences to Wand 5D(P<0.05). 2. The results(mean) of Microtensile bond strength were W:16.02, 5D:14.69, 30D:11.14MPa. Only 30D had statistically significant differences to Wand 5D(P<0.05). 3. There were positive correlation between Thickness of hybrid layer and microtensile bond strength(P<0.05).

• Bulletin of the Korean Chemical Society
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• v.23 no.1
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• pp.71-74
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• 2002

The apparent barrier height for charge transfer through an interfacial water layer between a Pt/Ir tip and a gold surface has been measured using STM technique. The average thickness of the interfacial water layer inside an STM junction was controlled by the amount of moisture. A thin water layer on the surface was formed when relative humidity was in the range of 10 to 80%. In such a case, electron tunneling through the thin water layer became the majority of charge transfers. The value of the barrier height for the electron tunneling was determined to be 0.95 eV from the current vs. distance curve, which was independent of the tip-sample distance. On the other hand, the apparent barrier height for charge transfer showed a dependence on tip-sample distance in the bias range of 0.1-0.5 V at a relative humidity of approximately 96%. The non-exponentiality for current decay under these conditions has been explained in terms of electron tunneling and electrochemical processes. In addition, the plateau current was observed at a large tip-sample distance, which was caused by electrochemical processes and was dependent on the applied voltage.

• Korean Journal of Hydrosciences
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• v.1
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• pp.61-71
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• 1990

The characteristics of radial thickness of ice jam at the center part of channel bends were analyzed briefly in this paper. Jam thickness in channel bends increases both toward the inner bank, and dowmstream. For this study, slope at the jam's underside was assumed to be liner with similarity of radial slope of bed in alluvial bends. Radial slope at the jam's underside in floating ice elements was estimated using the force equilibrium theory in the radial direction. The eqution which can be estimated the radial slope of ice jam was suggested using Falcon and Kennedy's bed layer theory. Experimental data, which were measured at the center part of cross-section in a single 180-degree bend, were compared to the calculated values using the suggested equtions. The result shows that the calcultated values were smaller than the measured ones. Ot is considered that the estimated value of shear stress in the radial direction may be smaller than the actual and two-layer model may be not suibable for alluvial bend flow.

• Current Optics and Photonics
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• v.3 no.1
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• pp.40-45
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• 2019

Adding tunability to biological light emitters offers an unprecedented technique in biological sensing and imaging. Here, we report a tunable, lithographic-free, planar, and ultrathin metal-insulator-metal (MIM) resonator capable of tuning the optical properties solely by a silk/sodium fluorescein hydrogel layer, a biocompatible light emitter. In water, the volume of the resonator was expanded by swelling, and then the resonant mode could be shifted. Simulations predicted the red-shifted resonance peak in transmission when the MIM was swollen in water. The red-shift could be attributed to the increase in the thickness of the silk hydrogel layer due to the absorbed water. The shift of the resonance could affect the fluorescence of the dye in the silk hydrogel layer.

• Solar Energy
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• v.7 no.2
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• pp.22-29
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• 1987

This paper dealed with thickness variation of bottom heat sotrage zone due to salinity and flow rate of extration hot brine in small test solar pond (0.5m wide, 0.5m high, 1.0m long). Testing apparatus and situation were follows: 7.1 cm of height of suction diffuser and 1.8cm of height of discharge diffuser above the test pond respectively, 0.3cm of slot size of suction diffuser, 1.0cm of slot size of discharge diffuser, 47cm of length of the slot; heating of hot water ($75^{\circ}C$) through separated hot water tank, discharge of the brine into storage zone through discharge diffuser, the extration of the brine through suction diffuser, circulation of the extracted brine through a heat exchanger (cooler). Following results were obtained through the experiments. 1. In small test solar pond, the typical three zone which showed up in real solar pond were established. 2. Richardson Number was used more effectively to confirm hydrodynamic stability of the stratified flow. 3. The thickness of non convective layer had a great effect on the heat storage of the bottom convective layer, then the temperature of bottom convective layer had a relation to that of upper convective layer. 4. Optimum operating condition in the test pond was on 10%-15% of salt concentration and $0.05m^3/hr$ of flow rate of extraction hot brine. 5. Following thickness of 3 zones were available to obtain under optimum operation condition: o bottom storage zone: $30%{\pm}10%$ of total pond depth o non-convective zone: $40%{\pm}10%$ of total pond depth o Upper surface zone: $20%{\pm}10%$ of total pond depth.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.04a
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• pp.251-263
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• 2011

This study was carried out in order to investigate the effect of pre-coating layer on top-coating layer. The coated paper with five different formulations were prepared. The properties of coated paper were measured and correlation between pre and top-coated layer was evaluated. Paper gloss was increased with addition of clay and GCC that has smaller particle size. Roughness was decreased with using smaller particle GCC, clay and talc. The highest thickness was obtained with talc. Brightness and whiteness of pre-coated layer were affected to top-coated layer. GCC 60 shows the highest and ununiform water adsorption during 1sec. The adsorption was higher with increasing coated weight. Talc shows the excellent water adsorption properties due to its wettability. These results indicate that final printability and properties of top coating layer can be controlled with adjusting pre-coating layer.