• Journal of Welding and Joining
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• v.15 no.3
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• pp.128-135
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• 1997

Reaction diffusion and formation of $Ni_3Al$phase with $L1_2$ structure have been studied in temperature range of 1432K to 1573K using the diffusion couple of (Ni-40, 5at%Al)/(Ni-14, 1at%Al) and (Ni-49, 2at%Al)/ (Nickel). The layer growth of Ni$_{3}$Al pyhase in the annealed diffusion couple was measured by optical microscope and electron probe microanalyzer (EPMA). The layer growth of $Ni_3Al$phase in diffusion zone obeyed the parabolic law without any indication of grain boundary effects. The layer growth of $Ni_3Al$phase in temperature range of 1423K to 1573K was mainly controlled by the volume diffusion mechanism. The rate of layer growth of $Ni_3Al$phase was found to be colsely related to the composition of intermetallic compound NiAl phase. The activation energy for layer growth of $Ni_3Al$phase was calculated to be 127kJ/mol.

• Journal of Welding and Joining
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• v.23 no.2
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• pp.75-80
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• 2005

The effect of chemical constituents of $(Cr,\;Fe)_7C_3$ carbide phase on its hardness in the chromium-carbide type Cr white iron hardfacing weld deposits has been investigated. In order to examine $(Cr,\;Fe)_7C_3$ carbide phase, a series of filler metals with varying chromium contents was used. The alloys were deposited once or twice on a mild steel plate using the self?shielding flux cored arc welding process. The hardness of $(Cr,\;Fe)_7C_3$ carbide phase was measured by the micro-Vickers hardness test. It was shown that hardness of $(Cr,\;Fe)_7C_3$ carbide phase increased with increasing Cr content in $(Cr,\;Fe)_7C_3$ carbide phase. This behavior of the hardness of $(Cr,\;Fe)_7C_3$ carbide phase was explained by the types of chemical bonds that hold atoms together in $(Cr,\;Fe)_7C_3$ carbide phase.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1973-1979
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• 2016

As technologies evolve, diverse 3D measurement techniques using cameras and pattern projectors have been developed continuously. In 3D measurement, high accuracy, fast speed, and easy implementation are very important factors. Recently, 3D measurement using multi-frequency fringe patterns for absolute phase computation has been widely used in the fringe projection profilometry. This paper proposes an improved method to compute the object's absolute phase using the reference plane's absolute phase and phase difference between the object and the reference plane. This method finds the object's absolute phase by adding the difference between the reference plane's wrapped phase and the object's wrapped phase to the reference plane's absolute phase already obtained in the calibration stage. Through this method, there is no need to obtain multi-frequency fringe patterns about new object for the absolute phase computation. Instead, we only need the object's phase difference relative to the reference planes's phase in the measurement stage.

• Progress in Superconductivity and Cryogenics
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• v.14 no.4
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• pp.28-31
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• 2012

We report the solid-liquid phase equilibria on the $GdBa_2Cu_3O_{7-{\delta}}$ (GdBCO) stability phase diagram in low oxygen pressures ($PO_2$) ranging from 1 to 100 mTorr. On the basis of the GdBCO stability phase diagram experimentally determined in low oxygen pressures, the isothermal sections of three different phase fields on log $PO_2$ vs. 1/T diagram were schematically constructed within the $Gd_2O_3-Ba_2CuO_y-Cu_2O$ ternary system, and the solid-liquid phase equilibria in each phase field were described. The invariant points on the phase boundaries include the following three reactions; a pseudobinary peritectic reaction of $GdBCO{\leftrightarrow}Gd_2O_3$ + liquid ($L_1$), a ternary peritectic reaction of $GdBCO{\leftrightarrow}Gd_2O_3+GdBa_6Cu_3O_y$ + liquid ($L_2$), and a monotectic reaction of $L_1{\leftrightarrow}GdBa_6Cu_3O_y+L_2$. A conspicuous feature of the solid-liquid phase equilibria in low $PO_2$ regime (1 - 100 mTorr) is that the GdBCO phase is decomposed into $Gd_2O_3+L_1$ or $Gd_2O_3+GdBa_6Cu_3O_y+L_2$ rather than $Gd_2BaCuO_5+L$ well-known in high $PO_2$ like air.

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1317-1322
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• 2014

Membrane disruption by an antimicrobial peptide (AMP) was investigated by measuring the $^2H$ solid-state nuclear magnetic resonance spectra of 1-palmitoyl-$d_{31}$-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC_$d_{31}$) in mixtures of POPC_$d_{31}$/cholesterol and either magainin 2 or aurein 3.3 deposited on thin cover-glass plates. The line shapes of the experimental $^2H$ solid-state nuclear magnetic resonance (SSNMR) spectra were best simulated by assuming the coexistence of a mosaic spread of bilayers containing pore structures and a fasttumbling isotropic phase or a hexagonal phase. Within a few days of incubation in a hydration chamber, an isotropic phase and a pore structure were induced by magainin 2, while in case of aurein 3.3 only an isotopic phase was induced in the presence of a bilayer phase. After an incubation period of over 100 days, alignment of the bilayers increased and the amount of the pore structure decreased in case of magainin 2. In contrast with magainin 2, aurein 3.3 induced a hexagonal phase at the peptide-to-lipid ratio of 1/20 and, interestingly, cholesterol was not found in the hexagonal phase induced by aurein 3.3. The experimental results indicate that magainin 2 is more effective in disrupting lipid bilayers containing cholesterol than aurein 3.3.

• Journal of the Korean Ceramic Society
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• v.16 no.4
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• pp.206-212
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• 1979

The phase relations and microstructure appeared at 1700℃ in a system of Si3N4-Al2O3-SiO2 were studied. The samples were pressurelessly sintered at 1700℃ for 1hr and reheated at 1600℃ for 1hr under nitrogen atmosphere. The compounds formed were identified by X-ray diffraction method and the microstrues were observed by SEM. The stable phases appeared in this system were X-phase, Si2ON2, β'-Si3N4 and Mullite. From the results of those experiments, it was concluded that the X-phase has very close composition to that proposed by G, K. Layden, Si3Al6O12N2. SEM photographs showed that Si2ON2 was a plate phase and X-phase was a rectagular plate phase.

• Korean Journal of Applied Biomechanics
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• v.17 no.1
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• pp.145-153
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• 2007

The purpose of this study is to compare and analyze the phase-by-phase elapsed time, the COG, the body joint angle changes and the angular velocities of each phase of Handspring Salto Forward Piked performed by 4 college gymnasts through 3D movement analysis program. 1. The average elapsed time for each phase was .13sec for Phase 1, .18sec for Phase 2, .4sec for Phase 3, and .3sec for Phase 5. The elapsed time for Phase 1 to Phase 3 handspring was .35sec on average and the elapsed time for Phase 4 to Phase 5 handspring salto forward piked was .7sec on average. And so it showed that the whole elapsed time was 1.44sec. 2. The average horizontal changes of COG were 93.2 cm at E1, 138. 5 cm at E2, 215.7 cm at E3, 369.2 cm at E4, 450.7 cm at E5, and 553.1 cm at E6. The average vertical changes of COG were 83.1 cm at E1, 71.3 cm at E2, 78.9 cm at E3, 93.7 cm at E4, 150.8 cm at E5, and 97.2 cm at E6. 3. The average shoulder joint angles at each phase were 131.6 deg at E1, 153.5 deg at E2, 135.4 deg at E3, 113.4 deg at E4, 39.6 deg at E5, and 67.5 deg at E6. And the average hip joint angles at each phase were 82.2 deg at E1, 60 deg at E2, 101.9 deg at E3, 161.2 deg at E4, 97.7 deg at E5, and 167 deg at E6. 4. The average shoulder joint angular velocities at each phase were 130.9deg/s E1, 73.1 deg/s at E2, -133.9 deg/s at E3, -194.4 deg/s at E4, 29.4 deg/s at E5, and -50.1 deg/s at E6. And the average hip joint angular velocities at each phase were -154.7 deg/s E1, -96.5 deg/s at E2, 495.9 deg/s at E3, 281.5 deg/s at E4, 90.3 deg/s at E5, and 181.7 deg/s at E6. The results shows that, as for the performance of handspring salto forward piked, it is important to move in short time and horizontally from the hop step to the point to place the hands on the floor and jump, and to stretch the hip joints as much as possible after the displacement of the hands and to keep the hip joints stretched and high in the vertical position at the takeoff. And it is also important to bend the shoulder joints and the hip joints fast and spin as much as possible after the takeoff, and to decrease the speed of spinning by bending he shoulder joints and the hip joints quickly after the highest point of COG and make a stable landing.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.233-238
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• 1997

An important assumption for the active power filter design using instantaneous power theory and the d-q transformation method in a 3-phase power system is based on balanced 3-phase system. However, under pratical conditions, the 3-phase power system can not be continuously balanced due to unbalanced loading. In this paper, a method to control the 3-phase active power filer using instantaneous power theory and the d-q transformation under unbalanced power system is presented and the theoretical results are verified by simulated results.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.4
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• pp.339-346
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• 2005

It is complex to realize the reference voltage vector by the space vector PWM method in three-leg two-phase inverter In this paper a new PWM technique for three-leg two-phase inverter fed two-phase induction motor is poroposed assuming that three-leg two-phase inverter is equivalent circuit for 'four-leg two-phase inverter with the connected two windings'. From assumption, six sectors are decreased to four sectors, and simple sinusoidal PWM method instead of SVPWM is applied to three-leg two-phase inverter. Also, the switching pattern to determine the switching periods at each sector is proposed. Practical verification of theoretical predictions is presented to confirm the capabilities of the new techniques.

• International Journal of Fluid Machinery and Systems
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• v.3 no.3
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• pp.245-252
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• 2010

It's known that pump head of centrifugal impeller with lager blade outlet angle is kept higher in air-water two phase flow condition, though the efficiency in water single phase flow condition is inferior. In the present study, a centrifugal impeller with variable blade outlet angles, that has higher efficiencies in both water single phase flow and air-water two phase flow conditions, is proposed. And the performances of the centrifugal impeller with variable blade outlet angles were experimentally investigated in both flow conditions of single and two-phase. In addition, effects of installing diffuser vanes on the performances of centrifugal pump with movable bladed impeller were also examined. The results are as follows: (1) The movable bladed impeller that proposed in this study is effective for higher efficiency in both water single phase and air-water two phase flow conditions. (2) When diffuser vanes are installed, the efficiency of movable bladed impeller decreases particularly at large water flow rate in water single-phase flow condition; (3) The performances of movable bladed impeller are improved by installing of diffuser vanes in air-water two-phase flow condition at relatively small water rate. The improvement by installing of diffuser vanes however disappears at large water flow rate.