• Food Engineering Progress
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• v.21 no.2
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• pp.116-125
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• 2017

This study aims to make extruded rice snack with high quality in texture and nutrition by adding mealworm. Addition of the mealworm has the merit to fill in high-quality protein and unsaturated fatty acids which are insufficient in rice. Thus, the physicochemical properties were investigated through the process of extrusion cooking. As the extrusion process varied, the die temperatures were set to $120^{\circ}C$ and $130^{\circ}C$. Also, the moisture contents were adjusted to 30% and 35%. The specific length, the expansion ratio, and the water absorption index increased as the added content of mealworm became higher. On the contrary, the density, the breaking strength, the apparent elastic modulus, and the water solubility index decreased. As mealworm and moisture content increased, DPPH radical scavenging activity significantly increased but the rancidity decreased. As a result, the addition of mealworm to the extruded rice snack was effective in improving texture, nutrition, and antioxidation.

• Journal of the Korean Ceramic Society
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• v.33 no.11
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• pp.1209-1216
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• 1996

MoSi2-Al2O3 composites were prepared by thermal explosion mode of self-propagating high temperature syn-thesis (SHS) using element powders of MoO3 Mo Si and Al. The combustion products of MoSi2 which have 10, 20, 30 and 40 wt% Al2O3 showed the molten state in the range of Mo to MoO3 6:1-9.5:1, 2:1-8:1, 1:1-5:1, and 1:1-3:1 (molar ratio) respectively. The combustion products which made least seperation the molten phase from the slag phase were in Mo/MoO3=9, 5:1, 8:1, 5:1 and 3:1 (molar ratio) respectively. Particles size of MoSi2 and Al2O3 in the combustion product were decreased as the molar ratio of Mo to MoO3 increase. By XRD analysis only MoSi2 and $\alpha$-Al2O3 peaks were identified in the combusion products, In case of MoSi2 containing 20wt% Al2O3 5.1wt% Al existed into MoSi2 grains and 30.7wt% Si and 7.7wt% Mo existed into Al2O3 grains. The relative density of MoSi2 containing 10, 20, 30 and 40 wt% Al2O3 were 82.7, 85.2, and 81.9% respectively. The fracture strength of MoSi2-Al2O3 composites increased with increasing Al2O3 and that of MoSi2-20wt% Al2O3 composite was 195 MPa.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.5
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• pp.415-421
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• 2013

CGI is gaining popularity in applications that require either greater strength, or lower weight than cast iron. Recently, compacted graphite iron has been used for diesel engine blocks, turbo housings and exhaust manifolds. This paper were assessed acoustic emission characteristics according to the mechanical properties change of degraded CGI340 during 1-24 hours at 873~1173 K. In results of pencil lead fracture test, the dominant frequency and the velocity of base metal were 97 kHz and 5490 m/sec, respectively. The base metal in a tensile test was obtained relatively high dominant frequency. However, the heat treated materials, the longer the heat treatment time, the higher the heat treatment temperature, were obtained in the area of lower frequencies. This phenomenon appears by long-term use.

• Journal of the Korean Ceramic Society
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• v.22 no.5
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• pp.9-16
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• 1985

Agglomeration of Y-PSZ and its related properties were studied. The ultrafine $ZrO_2$ powder containg 3 mol% $Y_2O_3$ was prepared by 1) coprecipitation method b) hot petroleum drying method c) sol-gel method and the characteristics of calcined powders and the microstructures of sintered body were observed. Powder prepared by the coprecipitation method was about 125$\AA$ in crystallite size and 0.1~1.0${\mu}{\textrm}{m}$ of intra-agglomerate pore size when calcined at $600^{\circ}C$ for 1 hour. because of small crystallite size and weak agglo merate strength resultant densification of sintered body was high. But above the temperature of 130$0^{\circ}C$ efflorescent phenomena due to anions attached to powder surface was observed. Powder prepared by hot petroleum drying method was 65$\AA$ in crystallite size and 1~10${\mu}{\textrm}{m}$ of intraagglome-rate pore size and it was observed that the agglemerates were formed during the calcining process. In this case despite of small crystallite size the rate of sintering was slow and the existing lenticular interagglomerate pore was not eliminated to the final stage of sintering. Powder prepared by sol-gel method showed solid agglomertes due to rapi dhydrolysis reaction. In this powder which involves strong solid agglomerates overall sintering rate was determined by the sintering between the agglomerates and therefore sinterability of powders made by sol-gel method was very poor.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.2
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• pp.13-21
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• 1999

Flip chip assembly directly on organic boards offers miniaturization of package size as well as reduction in interconnection distances resulting in a high performance and cost-competitive Packaging method. This paper describes the investigation of alternative low cost flip-chip mounting processes using electroless Ni/Au bump and anisotropic conductive adhesives/films as an interconnection material on organic boards such as FR-4. As bumps for flip chip, electroless Ni/Au plating was performed and characterized in mechanical and metallurgical point of view. Effect of annealing on Ni bump characteristics informed that the formation of crystalline nickel with $Ni_3$P precipitation above $300^{\circ}C$ causes an increase of hardness and an increase of the intrinsic stress resulting in a reliability limitation. As an interconnection material, modified ACFs composed of nickel conductive fillers for electrical conductor and non-conductive inorganic fillers for modification of film properties such as coefficient of thermal expansion(CTE) and tensile strength were formulated for improved electrical and mechanical properties of ACF interconnection. The thermal fatigue life of ACA/F flip chip on organic board limited by the thermal expansion mismatch between the chip and the board could be increased by a modified ACA/F. Three ACF materials with different CTE values were prepared and bonded between Si chip and FR-4 board for the thermal strain measurement using moire interferometry. The thermal strain of ACF interconnection layer induced by temperature excursion of $80^{\circ}C$ was decreased with decreasing CTEs of ACF materials.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.12
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• pp.1421-1426
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• 2014

To improve the inherent safety of the sodium-cooled fast reactor (SFR), the supercritical $CO_2$ ($S-CO_2$) Brayton cycle is being considered as an alternative power conversion system to steam the Rankine cycle. In the $S-CO_2$ system, a PCHE (printed circuit heat exchanger) is being considered. In this type of heat exchangers, diffusion bonding is used for joining the thin plates. In this study, the diffusion bonding characteristics of various austenitic alloys were evaluated. The tensile properties were measured at temperatures starting from the room temperature up to $650^{\circ}C$. For the 316H and 347H types of stainless steel, the tensile ductility was well maintained up to $550^{\circ}C$. However, the Incoloy 800HT showed lower strength and ductility at all temperatures. The microstructure near the bond line was examined to understand the reason for the loss of ductility at high temperatures.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1434-1439
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• 2004

CFRP composite materials have wide application in structure materials of airplane, ships, and aero space vehicles because of their high strength and stiffness. This paper is to study the effects of curvature and orientation angle on the penetration characteristics of CFRP laminate shell. They are staked with 8 Ply specimens [0$_2$/90$_2$]$_{s}$, [0/90$_2$/0]$_{s}$ and the stacked of outer plates degree with 12 Ply specimens [0$_3$/90$_3$]$_{s}$, [0$_2$/90$_2$/0]$_{s}$ and [90$_3$/0$_3$], [90$_2$/0$_2$/90]S. They are manufactured to varied curvature radius (R=100,150,200mm and $\infty$). They are cured by heating to the appropriate harding temperature(13$0^{\circ}C$) by mean of a heater at the vaccum bag of the autoclave. Test specimens were prepared with dimensions 100mm$\times$140mm. When the specimen is subjected to transverse impact by a steel ball, the velocity of the steel ball was measured both before and after impact by determining the time for it to pass two ballistic-screen sensor located a known distance apart. In general, kinetic energy after impact-kinetic energy before impact rised in all specimens. This study observed a fracture mode inside the specimen after a penetration test using a digital camera and it examined a fracture mode and a penetration mode to stack of outer orientation angle and curvature.rvature.

• Journal of the Korean Ceramic Society
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• v.42 no.8 s.279
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• pp.575-581
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• 2005

SiC-based ceramics are considered as candidate materials for the advanced nuclear energy systems such as the generation IV reactors and the fusion reactors due to their excellent high-temperature strength and irradiation resistance. The advanced nuclear energy systems and their main components adopting ceramic composites were briefly reviewed. A novel fabrication method of $SiC_f/SiC$ composites by introducing SiC whiskers was also described. In addition, the charged-particle irradiation ($Si^{2+}$ and $H^{+}$ ion) into CVD SiC was carried out to simulate the severe environments of the advanced nuclear reactors. SiC whiskers grown in the fiber preform increased the matrix infiltration rate by more than $60\%$ compared to the conventional CVI process. The highly crystalline and pure SiC showed little degradation in hardness and elastic modulus up to a damage level of 10 dpa at $1000^{\circ}C$.

• Composites Research
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• v.22 no.2
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• pp.1-6
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• 2009

The mechanical characteristics of gamma-ray irradiated UHMWPE specimens were investigated under various heat treatment conditions. The heat treatment was performed in the range of annealing and remelting temperatures. The annealing treatment below the temperature of $130^{\circ}C$ hardly induced changes in the tensile strength, the strain at the failure and the hardness. However the remelting treatment above $140^{\circ}C$ deteriorated those mechanical properties. It was shown in an FTIR analysis that the annealing treatment caused some oxidation of free radicals created by the pretreatment of the irradiation. These quantitative data represented by the behavior of mechanical properties might be used as basic informations for the design and analysis of various artificial joints.

• Journal of Adhesion and Interface
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• v.12 no.4
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• pp.111-116
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• 2011

The characteristics of natural resin, sap of the lacquer tree were examined as an adhesive for the ceramic conservation since it has such outstanding properties like corrosion resistance against acid and alkali, heat-resistance, waterproof, antiseptic and protection against insects. In order to utilize raw lacquer as an adhesive not under the hardening conditions of lacquer like high humidity (RH 75 to 85%) and high temperature (120 to $170^{\circ}C$), but under normal condition, isinglass and animal glue were added to raw lacquer at certain ratio. In addition, the viscosity and the drying time were measured and their possibilities of application were also investigated through measurement of tensile and adhesive strength. As a result of experiment, it was possible to dry at room temperature and RH $50{\pm}5%$ to mix with raw lacquer and glue, and the drying time of sample with animal glue was faster than that of isinglass. Furthermore, the adhesion of sample with glue was increased more than raw lacquer. It seems to be possible to use the environmental friendly traditional adhesive for the ceramic conservation and restoration, if there are studies or examinations of safety of applications on objects and weathering resistance.