• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.7
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• pp.288-292
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• 2003

AlM thin film has been deposited on A1$_2$O$_3$ substrate by reactive radio frequency(RF) magnetron sputtering method under various operating conditions such as working pressure, fraction of nitrogen partial pressure, and substrate temperature. Scanning Electron Microscope(SEM), X-ray Diffraction(XRD), and Atomic Force Microscope(AFM) have been measured to find out structural properties and preferred orientation of AlN thin films. SAW velocity of IDTs/AlN/Si structure was about 5038［㎧］ at the center frequency of 251.9［MHz］ and insertion loss was measured to be relatively low value of 35.6［dB］. SAW velocity of IDTs/AlN/A1$_2$O$_3$ structure was improved to be about 5960［㎧］ at the center frequency of 296.7［MHz］.

• Journal of the Korean institute of surface engineering
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• v.31 no.3
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• pp.171-176
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• 1998

Transparent conducting ITO (Indium Tin Oxide) thin films were prepared on soda lime glass by reactive dc magnetron sputtering mothod. The maaterial properties were measured by the X-ray diffraction meter (XRD) and atomic force microscopy (AFM) scanning. As a resuIts, the (400) park for $O_2 gas rate 2% grows uniquely as the preferred orientaon. However, the (400) peak exists at $O_2 gas rate 5% as well as the (222) peak appears abruptly as the main orietation. Both <100> and <111> grain alignments are consisted simultaneously in the XRE pattern of ITO thin films. The electrical charcteristics were esimated by the electrical resistivity, optical transmission, and Hall mobillty, ect. The resistivity of ITO thin film deposited at 4cm from the substrate center is increased from $2\times10^-4$ to $8\times10^-4\Omega$cm as a function of $O_2$ gas pressure (0~5%). The optical transmission curves with a rising of $O_2$ gas rate become shifted into longer wavelength range.

• Korean Journal of Materials Research
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• v.20 no.9
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• pp.494-499
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• 2010

Tin oxide thin films were prepared on borosilicate glass by rf reactive sputtering at different deposition powers, process pressures and substrate temperatures. The ratio of oxygen/argon gas flow was fixed as 10 sccm / 60 sccm in this study. The structural, electrical and optical properties were examined by the design of experiment to evaluate the optimized processing conditions. The Taguchi method was used in this study. The films were characterized by X-ray diffraction, UV-Vis spectrometer, Hall effect measurements and atomic force microscope. Tin oxide thin films exhibited three types of crystal structures, namely, amorphous, SnO and $SnO_2$. In the case of amorphous thin films the optical band gap was widely spread from 2.30 to 3.36 eV and showed n-type conductivity. While the SnO thin films had an optical band gap of 2.24-2.49 eV and revealed p-type conductivity, the $SnO_2$ thin films showed an optical band gap of 3.33-3.63 eV and n-type conductivity. Among the three process parameters, the plasma power had the most impact on changing the structural, electrical and optical properties of the tin oxide thin films. It was also found that the grain size of the tin oxide thin films was dependent on the substrate temperature. However, the substrate temperature has very little effect on electrical and optical properties.

• Steel and Composite Structures
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• v.31 no.1
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• pp.13-25
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• 2019

Reactive powder concrete (RPC) is a type of ultra-high strength concrete that has a relatively high brittleness. However, its ductility can be improved by confinement, and the use of RPC in composite RPC filled steel tube columns has become an important subject of research in recent years. This paper aims to present an experimental study of axial capacity calculation of RPC filled circular steel tube columns. Twenty short columns under axial compression were tested and information on their failure patterns, deformation performance, confinement mechanism and load capacity were presented. The effects of load conditions, diameter-thickness ratio and compressive strength of RPC on the axial behavior were further discussed. The experimental results show that: (1) specimens display drum-shaped failure or shear failure respectively with different confinement coefficients, and the load capacity of most specimens increases after the peak load; (2) the steel tube only provides lateral confinement in the elastic-plastic stage for fully loaded specimens, while the confinement effect from steel tube initials at the set of loading for partially loaded specimens; (3) confinement increases the load capacity of specimens by 3% to 38%, and this increase is more pronounced as the confinement coefficient becomes larger; (4) the residual capacity-to-ultimate capacity ratio is larger than 0.75 for test specimens, thus identifying the composite columns have good ductility. The working mechanism and force model of the composite columns were analyzed, and based on the twin-shear unified strength theory, calculation methods of axial capacity for columns with two load conditions were established.

• Advances in concrete construction
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• v.17 no.2
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• pp.75-92
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• 2024

High Strength steel reinforced Reactive Powder Concrete (RPC) Beam is a new type of beams which has evident advantages than the conventional concrete beams. However, there is limited research on the shear bearing capacity of high-strength steel reinforced RPC structures, and there is a lack of theoretical support for structural design. In order to promote the application of high-strength steel reinforced RPC structures in engineering, it is necessary to select a shear model and derive applicable calculation methods. By considering the shear span ratio, steel fiber volume ratio, longitudinal reinforcement ratio, stirrup ratio, section shape, horizontal web reinforcement ratio, stirrup configuration angle and other variables in the shear test of 32 high-strength steel reinforced RPC beams, the applicability of three theoretical methods to the shear bearing capacity of high-strength steel reinforced RPC beams was explored. The plasticity theory adopts the RPC200 biaxial failure criterion, establishes an equilibrium equation based on the principle of virtual work, and derives the calculation formula for the shear bearing capacity of high-strength steel reinforced RPC beams; Based on the Strut and Tie Theory, considering the softening phenomenon of RPC, a failure criterion is established, and the balance equation and deformation coordination condition of the combined force are combined to derive the calculation formula for the shear bearing capacity of high-strength reinforced RPC beams; Based on the Rankine theory and Rankine failure criterion, taking into account the influence of size effects, a calculation formula for the shear bearing capacity of high-strength reinforced RPC beams is derived. Experimental data is used for verification, and the results are in good agreement with a small coefficient of variation.

• Food Science of Animal Resources
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• v.38 no.5
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• pp.970-980
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• 2018

We evaluated the effects of pre-cooking methods on the quality of reheated marinated pork loin. Frozen marinated pork loins cooked using various methods (boiling, grilling, pan frying, infrared cooking, and superheated steam cooking) were reheated in a microwave, and their pH, color, cooking loss, re-heating loss, total loss, thiobarbituric acid reactive substance (TBARS) value, sensory properties, and shear force were determined. Although all parameters varied with different cooking methods, lightness values and TBARS values showed the tendency to decrease and increase, respectively, after reheating. Superheated steam-cooked samples showed the lowest values of cooking loss, total loss, TBARS value, and shear force (p<0.05) and the highest lightness, redness, and yellowssness values and juiciness, chewiness, and overall acceptability scores (p<0.05). These results show that pre-cooking with superheated steam maintains the quality characteristics of marinated pork loin upon reheating. Therefore, pre-cooking with superheated steam may be beneficial for the commercial distribution of frozen cooked marinated pork loin.

• Food Science of Animal Resources
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• v.38 no.5
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• pp.950-958
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• 2018

The physicochemical characteristics and oxidative stability of wet-aged and dry-aged pork cuts were investigated at different aging periods (1, 7, 14 and 21 d). Samples were assigned into four groups in terms of shoulder blade-wet aging (SW), shoulder blade-dry aging (SD), belly-wet aging (BW), and belly-dry aging (BD). SD showed significantly higher pH at 21 d of aging than the other samples. Wet-aged cuts had significantly higher released water (RW) %, lightness ($L^*$) and shear force compared to the dry-aged meats. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed greater degradation of proteins for dry-aged cuts than the wet-aged cuts. At the end of aging, wet-aged cuts showed significantly lower thiobarbituric acid-reactive substances (TBARS) value than the dry-aged samples, indicating higher oxidative stability for wet-aged pork cuts. However, dry-aging led to higher degradation of proteins resulting in increased water-holding capacity (WHC) and decreased shear force value.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.57-60
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• 2005

The objective of this paper is to investigate and analyze the behaviour of prestressed I section structural members constructed with ultra high perfomance steel fiber reinforced cementitious concrete (SFR-UHPC). This material is known as reactive powder concrete (RPC) mixed with domestic materials and its compressive strength is over 150MP. The parameters of test specimens were span to depth ratio, prestressing force, prestressing wire placement and web width. Most influential parameter to determine the failure mode between shear and flexural action was proved to be shear span ratio. The characteristics of ultra high-strength concrete is basically brittle, but due to the steel fiber reinforcement behaviour of this structure member became ductile after the peak load. As a result of the test, the stress block of compressive zone should be redefined. The proposed analytical calculation of internal force capacity based by plastic analysis gave a good prediction for the shear and flexural strength of specimens. The numerical verification of the finite element model which constitutive law developed for Mode I fracture of fiber reinforced concrete correctly captured the overall behaviour of the specimens tested.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1572-1575
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• 1996

A new type $Cu_{x}N/Cu/Cu_{x}N$ thin film electrode material with high adhesion to glass was developed by the dc reactive planar magnetron sputtering system for the PDP(Plasma Display Panel). The adhesive force of the $Cu_{x}N$ thin film was in the range of $20{\sim}40(N)$ under the conditions of the $N_2$ partial pressure of 15%, discharge current of 70mA, discharge voltage of 450V and substrate bias voltage of -100V. The adhesive force was depended on the $N_2$ partial pressure, discharge current and substrate bias voltage.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.4
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• pp.582-587
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• 2007

The pale, soft, exudative (PSE) syndrome lowers storage quality and consumers acceptability in the particular meat. With the increase in the consumption of parted chickens in Korean meat consumption trade, a parallel increase in the concern over the PSE status of chickens have been noticed. The present study focused on the PSE status of broiler's breast to investigate the effects of different degrees of PSE on its quality and storage characteristics. A total of 46 broiler chickens of 35 days old averaging 1,251-1,350 g were selected for the study. Breast separated and skin was removed. The breast meat was stored at $4^{\circ}C$ for 3 days and were analysed for pH, lightness, yellowness, redness, shear force, water-holding capacity (WHC), cooking loss, Thiobarbituric acid reactive substances (TBARS) and Volatile basic nitrogen (VBN) on day 1 and 3 during the storage. Increase in the degree of broilers breast PSE during storage caused fall in pH and shear force and increase in lightness, cooking loss, TBARS, VBN. Broilers breast PSE status confirms the actual pale soft and exudative nature of meat.