• Horticultural Science & Technology
• /
• v.28 no.4
• /
• pp.656-663
• /
• 2010

In order to improve the consumer acceptance of fragrant yellow hybrids of $Phalaenopsis$ ($Phal.$), crosses between yellow hybrid varieties were made and the obtained hybrids were investigated for horticultural characteristics as well as difference in fragrance patterns. Cross combination of $Phal.$ Brother lawrence and $Phal.$ Brother saragold yielded good seedling population of 500 plants. Segregation was noticed in color density, spot and stripe patterns on yellow color base of petal and also in fragrance. Six lines with multi-branch on flower stalk and strong fragrance flower were finally selected. Volatile fragrance components were compared among $Phal.$ Brother lawrence, $Phal.$ Brother saragold and their hybrids by GC/SAW electronic nose. In the derivative pattern of chromatogram and polar derivative pattern of fragrance, similar dominant peaks appeared on retention time 7-9 s and some hybrid lines had two strong peaks on retention time 20-25 s, respectively. Also in polar frequency pattern of fragrance obtained by $VaporPrint^{TM}$ image analysis among parent flowers and hybrids, an identical strong peak near 8 s of retention time was shown. This single fragrance component is considered a key element of fragrance in $Phal.$ Brother lawrence, $Phal.$ Brother saragold and their hybrids. This peak could be used as a marker for the breeding of fragrance in $Phalaenopsis$.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.10
• /
• pp.1881-1891
• /
• 2000

Cenosphere particles of different fly ash formed at the pulverized coal power plant were hollow sphere or filled with small particles inside solid particles. And size was relatively larger than other fly ash particles as well as specific gravity was small to suspend in the water. In this paper, it was demonstrated to contain a variety of morphological particle type, and the physical and chemical properties related to the cenosphere and fly ash particles. Furthermore it was estimated the possibility to reuse the cenosphere particles on the base of cenosphere properties. Cenosphere formation resulted from melting of mineral inclusion in coal, and then gas generation inside the molten droplet. As the aluminosilicate particle was progressively heated, a molten surface layer developed around the solid core. Further heating leaded to cause the formation of fine particles at the core. The mass median diameter(MMD) of cenosphere particles was $123.11{\mu}m$ and the range of size distribution was $100{\sim}200{\mu}m$ with single modal. It was represented that specific density was $0.67g/cm^3$ fineness was $1135g/cm^3$. The chemical components of cenosphere were similar to other fly ash including $SiO_2$, $Al_2O_3$, but the amount of the chemical component was different respectively. In the case of fly ash, $SiO_2$ concentration was 54.75%, and $Al_2O_3$ concentration was 21.96%, so this two components was found in 76.71% of the total concentration. But in the case of cenosphere, it was represented that $SiO_2$ concentration was 59.17% and $Al_2O_3$ concentration was 30.16%, so this two components was found in 89.33% of the total concentration. Glassy component formed by the aluminosilicate was high in the cenosphere, so that it was suitable to use insulating heat material.

• Korean Journal of Materials Research
• /
• v.8 no.7
• /
• pp.648-652
• /
• 1998

TIG remelting was performed to harden the surface of automobile earn shaft. Multipass remelting was conducted in longitudinal direction under argon gas atmosphere. The microstructure of as-east earn shaft was gray iron which consisted of flake graphite and pearlitic matrix. The remelted area had microstructue of both fine pearlite and ledeburite structure that consisted of globular austenite and $Fe_3C$. Hardness for as-cast earn shaft had HRc 25~28, however it increased at remelted area to HRc 53~55. Black line was found at heat affected zone next to the fusion line, that is remelt area of previous pass, during multipass remelting. Black line was identified as graphite, which was transformed from $Fe_3C$. in the ledeburite structure. It is observed that all graphites were nucleated at $Fe_3C$. and matrix interface. High density energy laser remelting process was also applied to verify whether black line could be eliminated. However, black line was still existed as observed in TIG remelting process. Regraphitization was simulated on the ledeburitic structure specimen using Gleeble 1500 with conditions of 1100 and 100$0^{\circ}C$ for 0.5, I, 3, 5 and 1Osee. From the fact that graphite was formed even at the simulation condition of 100$0^{\circ}C$ for 0.5sec, it is seen that regraphitization is an inevitable phenomenon generated whatever processes used during multipass overlap remelting.

• Journal of the Korean Vacuum Society
• /
• v.15 no.4
• /
• pp.380-386
• /
• 2006

In this study, we had designed and fabricated the plasma focus device which can generate the light source for EUV(Extreme Ultra Violet) lithography. And we also have investigated the basic electrical characteristics of currents, voltages, resistance and inductance of this system. Voltage and current signals were measured by C-dot and B-dot probe, respectively. We applied various voltages of 1.5, 2, 2.5 and 3 kV to the anode electrode and observed voltages and current signals in accordance with various Ar pressures of 1 mTorr to 100 Torr in diode chamber. It is observed that the peak values of voltage and current signals were measured at 300 mTorr, where the inductance and impedance were also estimated to be 73 nH and $35 m{\Omega}$ respectively. The electron temperature has been shown to be 13000 K at the diode voltage of 2.5 kV and this gas pressure of 300 mTorr. It is also found that the ion density Ni and ionization rate 0 have been shown to be $N_i = 8.25{\times}10^{15}/cc$ and ${\delta}$= 77.8%, respectively by optical emission spectroscopy from assumption of local thermodynamic equilibrium(LTE) plasma.

• Korean Journal of Materials Research
• /
• v.2 no.6
• /
• pp.428-435
• /
• 1992

AISI 4600 Iron powder was mixed with 0~1.0% phosphor as F$e_2$P powder and/or 0~0.8% carbon as graphite powder in rotating mixer. Mixed powder was pressed 800MPa in double-punch mould. Compacts were sintered at 115$0^{\circ}C$for 30 min. in vacuum or mixed hydrogen and nitrogen gas. Sintered compacts were ground and polished, and etched by 2% nital etchant. The microstructure was observed by image analyzer and optical microscope. Density and microhardness were tested by ASTM B3l2 and Microvickers hardness tester. The results obtained were as follows : (1) As the amount of F$e_2$P powder increased, sintered microstructure showed more densified effect and the grain size was larger. (2) The shape of pore was rounded and the number of pore was decreased by F$e_2$P addition. But mean pore size was larger with F$e_2$P content. (3) Simultaneous alloying addition of F$e_2$P and graphite brought about larger grain growth than respective addition. (4) Sintering atmosphere did not affect the microstructure. (5) Hardness of sintered compact increased with phosphrous and carbon content.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.2 no.1
• /
• pp.10-19
• /
• 1992

Mn - Zn Ferrite has physical properties of the high initial permeability, saturation magnetic flux density, and low loss factor as a representative magnetic material of soft ferrites, in addition the mechanical property is excellent as a single crystal. Therefore it is important electronic components and used for VTR Head. Mn - Zn Ferrite single crystals with the diameter 8mm were grown in atmosphere mixed with $O_2$ and Ar gas by the Floating Zone(FZ) method that impurities can not be incorporated to the crystals because of not-using the crucible to put in the melt, and the sharp temperature gradient results from making a focus at one point utilizing the infrared ray emitted from the halogen lamp as a heat source. During the crystal growing, the highest temperature of melting area was maintained to be $1650^{\circ}C$, growth rate and rotation rate were 10 mm/hr, 20 rpm respectively. The phases and the growth directions of crystals were determined from the analysis of X RD patterns, Laue, TEM diffraction patterns and etch pit shapes were observed by the optical microscope through the chemical etching. The corelation of optimum conditions for acquiring the better crystals was found out with the growth rate, the length and diameter of melt at the interface according to the diameter of feed rod, and the patterns of growing interface also studied.

• Geophysics and Geophysical Exploration
• /
• v.10 no.1
• /
• pp.1-18
• /
• 2007

Non-linear elastic wavefield inversion is a powerful method for estimating elastic parameters for physical constraints that determine subsurface rock and properties. Here, I introduce six elastic-wave velocity models by reconstructing elastic-wave velocity variations from real data and a 2D elastic-wave velocity model. Reflection seismic data information is often decoupled into short and long wavelength components. The local search method has difficulty in estimating the longer wavelength velocity if the starting model is far from the true model, and source frequencies are then changed from lower to higher bands (as in the 'frequency-cascade scheme') to estimate model elastic parameters. Elastic parameters are inverted at each inversion step ('simultaneous mode') with a starting model of linear P- and S-wave velocity trends with depth. Elastic parameters are also derived by inversion in three other modes - using a P- and S-wave velocity basis $('V_P\;V_S\;mode')$; P-impedance and Poisson's ratio basis $('I_P\;Poisson\;mode')$; and P- and S-impedance $('I_P\;I_S\;mode')$. Density values are updated at each elastic inversion step under three assumptions in each mode. By evaluating the accuracy of the inversion for each parameter set for elastic models, it can be concluded that there is no specific difference between the inversion results for the $V_P\;V_S$ mode and the $I_P$ Poisson mode. The same conclusion is expected for the $I_P\;I_S$ mode, too. This gives us a sound basis for full wavelength elastic wavefield inversion.

• Journal of Environmental Science International
• /
• v.18 no.3
• /
• pp.299-308
• /
• 2009

We manufactured PVA-derived hydrogels using a foam generation technique that has been widely used to prepare colloidal gas aphrons(CGA). These gels were differentiated to the conventional gels such as for medical or pharmaceutical applications, which have tiny pores and some crystalline structure. Rather these should be used in de-pollution devices or adhesion of cells or biomolecules. The crosslinkers used in this work were amino acid, organic acid, sugars and lipids(vitamins). The structures of the gels were observed in a scanned electron microscope. Amino acids gels showed remarkably higher swelling ratios probably because their typical functional groups help constructing a highly crosslinked network along with hydrogen bonds. Boric acid and starch would catalyze dehydration while structuring to result in much lower water content and accordingly high gel content, leading to less elastic, hard gels. Bulky materials such as ascorbic acid or starch produced, in general, large pores in the matrices and also nicotinamide, having large hydrophobic patches was likely to enlarge pore size of its gels as well since the hydrophobicity would expel water molecules, thus leading to reduced swelling. Hydrophilicity(or hydrophobicity), functional groups which are involved in the reaction or physical linkage, and bulkiness of crosslinkers were found to be more critical to gel's cross linking structure and its density than molecular weights that seemed to be closely related to pore sizes. Microscopic observation revealed that pores were more or less homogeneous and their average sizes were $20{\mu}m$ for methionine, $10-15{\mu}m$ for citric acid, $50-70{\mu}m$ for L-ascorbic acid, $30-40{\mu}m$ for nicotinamide, and $70-80{\mu}m$ for starch. Also a sensory test showed that amino acid and glucose gels were more elastic meanwhile acid and nicotinamide gels turned out to be brittle or non-elastic at their high concentrations. The elasticity of a gel was reasonably correlated with its water content or swelling ratio. In addition, the PVA gel including 20% ascorbic acid showed fair ability of cell adherence as 0.257mg/g-hydrogel and completely degraded phenanthrene(10 mM) in 240 h.

• Journal of Information Display
• /
• v.11 no.1
• /
• pp.8-11
• /
• 2010

In this study, a new thin films passivation technique using Zn with high electronegativity and $MgF_2$, a fluorine material with better optical transmittance than the sealing film materials that have thus far been reported was proposed. Targets with various ratios of $MgF_2$ to Zn (5:5, 4:6 and 3:7) were fabricated to control the amount of Zn in the passivation films. The Mg-Zn-F films were deposited onto the substrates and Zn was located in the gap between the lattices of $MgF_2$ without chemical metathesis in the Mg-Zn-F films. The thickness and optical transmittance of the deposited passivation films were approximately 200 nm and 80%, respectively. It was confirmed via electron dispersive spectroscopy (EDS) analysis that the Zn content of the film that was sputtered using a 4:6 ratio target was 9.84 wt%. The Zn contents of the films made from the 5:5 and 3:7 ratio targets were 2.07 and 5.01 wt%, respectively. The water vapor transmission rate (WVTR) was determined to be $38^{\circ}C$, RH 90-100%. The WVTR of the Mg-Zn-F film that was deposited with a 4:6 ratio target nearly reached the limit of the equipment, $1\times10^{-3}\;gm^2{\cdot}day$. As the Zn portion increased, the packing density also increased, and it was found that the passivation films effectively prevented the permeation by either oxygen or water vapor. To measure the characteristics of gas barrier, the film was applied to the emitting device to evaluate their lifetime. The lifetime of the applied device with passivation was increased to 25 times that of the PLED device, which was non-passivated.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.6 no.3
• /
• pp.351-359
• /
• 1996

We have investigated the effect of hydrogen plasma on the formation of InAs QDs (quantum dots) structure by using a CBE (chemical beam epitaxy)system equipped with ECR (electron cyclotron resonance) plasma source. It is confirmed that the formation of self-organized InAs-QDs on GaAs is started after the growth of InAs layer up to 2.6 ML (monolayer) with the irradiation of hydrogen plasma while it is started after 1.9 ML without hydrogen gas and hydrogen plasma through the observation of RHEED patterns. Density and size of the QDs formed at $T_{sub}=370^{\circ}C$ are $1.9{\times}10^{11}cm^{-2}$ and 17.7 nm without hydrogen plasma, and $1.3{\times}10^{11}cm^{-2}$ and 19.4 nm with hydrogen plasma, respectively. It is also observed from the PL(photoluminescence) measurement on InAs-QDs that red shift in PL peak energy and broadening in FWHM (full width at half maximum)of PL peak caused by the effects of hydrogen plasma on the increment of size and its distribution. These effects of hydrogen plasma are considered as a act of atomic hydrogen which enhances the layer-growth of InAs on GaAs resulted from the relief of misfit strain between GaAs substrate and InAs.