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        검색결과 154

        61.
        2010.08 구독 인증기관 무료, 개인회원 유료
        In this study, we propose a new method for generating candidate solutions based on both the Cauchy and the Gaussian probability distributions in order to use the merit of the solutions generated by these distributions. The Cauchy probability distribution has larger probability in the tail region than the Gaussian distribution. Thus, the Cauchy distribution can yield higher probabilities of generating candidate solutions of large-varied variables, which in turn has an advantage of searching wider area of variable space. On the contrary, the Gaussian distribution can yield higher probabilities of generating candidate solutions of small-varied variables, which in turn has an advantage of searching deeply smaller area of variable space. In order to compare and analyze the performance of the proposed method against the conventional method, we carried out experiments using benchmarking problems of real valued functions. From the result of the experiment, we found that the proposed method based on the Cauchy and the Gaussian distributions outperformed the conventional one for most of benchmarking problems, and verified its superiority by the statistical hypothesis test.
        4,000원
        62.
        2010.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Multi shell graphite coated Ag nano particles with core/shell structure were successfully synthesized by pulsed wire evaporation (PWE) method. Ar and (10 vol.%) gases were mixed in chamber, which played a role of carrier gas and reaction gas, respectively. Graphite layers on the surface of silver nano particles were coated indiscretely. However, the graphite layers are detached, when the particles are heated up to in the air atmosphere. In contrast, the graphite coated layer was stable under Ar and atmosphere, though the core/shell structured particles were heated up to . The presence of graphite coated layer prevent agglomeration of nanoparticles during heat treatment. The dispersion stability of the carbon coated Ag nanoparticles was higher than those of pure Ag nanoparticles.
        4,000원
        63.
        2010.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Twinning-induced plasticity (TWIP) steels have attracted great attention due to their excellent mechanical properties of high tensile strength (over 800MPa) and high ductility (over 50%), which result from the high strain hardening due to the mechanical twin formation during plastic deformation. The purpose of this study is to investigate the effect of annealing temperature and alloying elements on the mechanical properties of Fe-18Mn-0.6C TWIP steel. In 1.5%Al TWIP steel with 0.123%Ti content, the average recrystallized grain size was reduced to 2.5 μm by cold rolling and annealing at 800˚C for 5 min, because of the pinning effect of the fine TiC carbides on grain coarsening. The tensile strength was decreased and the ductility was improved with the increase of the annealing temperature. However, a reversion of hardness and yield strength happened between 750˚C and 800˚C due to TiC and M3C type precipitation. 0.56% Ni added TWIP steel exhibited relatively lower yield strength, because Ni precipitates were not formed during the annealing process. When this specimen was annealed at 800˚C for 5min, the tensile strength and elongation were revealed at 1096MPa and 61.8%, respectively.
        4,000원
        64.
        2009.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Transparent ITO films were deposited on a polycarbonate substrate with RF magnetron sputtering in a pure argon(Ar) and oxygen (O2) gas atmosphere, and then post deposition electro annealed for 20 minutes in a 4×10-1Pa vacuum. Electronbombardment with an accelerating voltage of 100V increased the substrate temperature to 120oC. XRD analysis of the depositedITO films did not show any diffraction peaks, while electro annealed films indicated the growth of crystallites on the (211), (222),and (400) planes. The sheet resistance of ITO films decreased from 103 to 82Ω/□. The optical transmittance of ITO films inthe visible wavelength region increased from 85 to 87%. Observation of the work function demonstrated that the electro-annealingincreased the work function of ITO films from 4.4 to 4.6eV. The electro annealed films demonstrated a larger figure of meritof 3.0×10-3Ω-1 than that of as deposited films. Therefore, the electro annealed films had better optoelectrical performances thanas deposited ITO films.
        4,000원
        65.
        2009.08 구독 인증기관·개인회원 무료
        In the present study, we have used an annealing-control-primer (ACP)-based differentially display RT-PCR method to identify salt-stress-induced differentially expressed genes (DEGs) in barley leaves. Using 120 ACPs, a total of 11 up-regulated genes were identified and sequenced. Temporal expression patterns of some up-regulated DEGs in response to salt stress were further analyzed by Northern blot analysis. The possible roles of these identified genes are discussed within the context of their putative role in response to salt stress. Thus, the identification of some novel genes-such as SnRK1-type protein kinase; 17 kDa, class I, small heat shock protein; and RNase S-like protein precursor genes-may offer a new avenue for better understanding the salt stress response in plants, knowledge which might be helpful for developing future strategies.
        66.
        2009.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Polymer Light Emitting Diodes (PLEDs) with an ITO/PEDOT:PSS/PVK/PFO-poss/LiF/Al structure were prepared on plasma-treated ITO/glass substrates using spin-coating and thermal evaporation methods. The annealing effects of the PFO-poss film when it acts as the emission layer were investigated by using electrical and optical property measurements. The annealing conditions of the PFO-poss emission film were 100 and 200˚C for 1, 2 and 3 hours, respectively. The luminance increased and the turn-on voltage decreased when the annealing temperature and treatment time increased. After examining the Luminance-Voltage (L-V) properties of the PLED, the maximum luminance was found to be 1497 cd/m2 at 11 V for the device when it was annealed at 200˚C for 3 hours. The peak intensity of the PLED emission spectra at approximately 525 nm in wavelength increased when the annealing temperature and time of the PFO-poss film increased. These results suggest that the light emission color shifted from blue to green.
        4,000원
        67.
        2009.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Transparent Sn-doped In2O3 (ITO) single-layer and ITO/Au/ITO multilayer films were deposited onglass substrates by reactive magnetron sputtering to compare the properties of the films. They were thenannealed in a vacuum of 1×10-2 Pa at temperatures ranging from 150 to 450oC for 20 min to determinethe effect of the annealing temperature on the properties of the films. As-deposited 100nm thick ITO filmsexhibit a sheet resistance of 130Ω/□ and optical transmittance of 77% at a wavelength length of 550nm. Byinserting a 5nm-thick Au layer in ITO/metal/ITO (IMI) films, the sheet resistance was decreased to as lowas 20Ω/□ and the optical transmittance was decreased to as little as 73% at 550nm. Post-deposition annealingof ITO/Au/ITO films led to considerably lower electrical resistivity and higher optical transparency. In the X-ray diffraction pattern, as-deposited ITO films did not show any diffraction peak, whereas as-deposited ITO/Au/ITO films have Au (222) and In2O3 (110) crystal planes. When the annealing temperature reached the 150- 450oC range, the both diffraction peak intensities increased significantly. A sheet resistance of 8Ω/□ and anoptical transmittance of 82% were obtained from the ITO/Au/ITO films annealed at 450oC.
        3,000원
        68.
        2009.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The effect of annealing under argon atmosphere on hydrogenated amorphous silicon (a-Si:H) thin films deposited at room temperature and 300˚C using Radio Frequency (RF) magnetron sputtering has been investigated. For the films deposited at room temperature, there was not any increase in hydrogen content and optical band gap of the films, and as a result, quality of the films was not improved under any annealing conditions. For the films deposited at 300˚C, on the other hand, significant increases in hydrogen content and optical band gap were observed, whereas values of microstructure parameter and dark conductivity were decreased upon annealing below 300˚C. In this study, it was proposed that the Si-HX bonding strength is closely related to deposition temperature. Also, the improvement in optical, electrical and structural properties of the films deposited at 300˚C was originated from thermally activated hydrogen bubbles, which were initially trapped at microvoids in the films.
        4,000원
        69.
        2008.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Modified thermal annealing was applied to the activation of the polycrystalline silicon films doped as p-type through implantation of B2H6. The statistical design of experiments was successfully employed to investigate the effect of rapid thermal annealing on activation of polycrystalline Si doped as p-type. In this design, the input variables are furnace temperature, power of halogen lamps, and alternating magnetic field. The degree of ion activation was evaluated as a function of processing variables, using Hall effect measurements and Raman spectroscopy. The main effects were estimated to be furnace temperature and RTA power in increasing conductivity, explained by recrystallization of doped ions and change of an amorphous Si into a crystalline Si lattice. The ion activation using rapid thermal annealing is proven to be a highly efficient process in low temperature polycrystalline Si technology.
        4,000원
        70.
        2008.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The effect of silver nanoparticles (NPs) incorporation on the electronic properties of poly (3, 4-ethylenedioxythiphene) : poly(styrenesulfonate) (PEDOT : PSS) films was investigated. The surface of silver NPs was stabilized with trisodium citrate to control the size of silver NPs and prevent their aggregation. We obtained ca. 5 nm sized silver NPs and dispersed NPs in PEDOT : PSS solution. Sheet resistance, surface morphology, bonding state, and work function values of the PEDOT : PSS films were modified by silver NPs incorporation as well as annealing temperature. Sodium in silver NPs solution could lead to a decrease of work function of PEDOT : PSS; however, large content of silver NPs have an effect on the increase in work function, resulting from charge localization on the silver NPs and a decrease in the number of charge-trapping-related defects by chemical bond formation.
        3,000원
        71.
        2008.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The effect of annealing treatment conditions on the interfacial adhesion energy between electrolessplated Ni film and polyimide substrate was evaluated using a 180˚ peel test. Measured peel strength values are 26.9±0.8, 22.4±0.8, 21.9±1.5, 23.1±1.3, 16.1±2.0 and 14.3±1.3g/mm for annealing treatment times during 0, 1, 3, 5, 10, and 20 hours, respectively, at 200˚C in ambient environment. XPS and AES analysis results on peeled surfaces clearly reveal that the peeling occurs cohesively inside polyimide. This implies a degradation of polyimide structure due to oxygen diffusion through interface between Ni and polyimide, which is also closely related to the decrease in the interfacial adhesion energy due to thermal treatment in ambient conditions.
        4,000원
        72.
        2008.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Single crystal ZnIn2S4 layers were grown on thoroughly etched semi-insulating GaAs(100) substrateat 450oC with hot wall epitaxy (HWE) system by evaporating ZnIn2S4 source at 610oC. The crystalline structureof the single crystal thin films was investigated by the photoluminescence (PL) and double crystal X-ray rockingcurve (DCRC). The temperature dependence of the energy band gap of the ZnIn2S4 obtained from theabsorption spectra was well described by the Varshni’s relation, Eg(T)=2.9514eV-(7.24×10−4eV/K)T2/(T+489K). After the as-grown ZnIn2S4 single crystal thin films were annealed in Zn-, S-, and In-atmospheres, theorigin of point defects of ZnIn2S4 single crystal thin films has been investigated by the photoluminescence (PL)at 10K. The native defects of VZn, VS, Znint, and Sint obtained by PL measurements were classified as a donorsor acceptors type. And we concluded that the heat-treatment in the S-atmosphere converted ZnIn2S4 singlecrystal thin films to an optical p-type. Also, we confirmed that In in ZnIn2S4/GaAs did not form the nativedefects because In in ZnIn2S4 single crystal thin films existed in the form of stable bonds.
        4,000원
        73.
        2008.05 구독 인증기관·개인회원 무료
        We have previously shown that the larvae of swallowtail butterfly, Papilio xuthus, exhibit substantial antibacterial activity in the hemolymph, upon challenging with bacterial lipopolysaccharide (LPS). Here we report the isolation and molecular characterization of several immune inducible genes that are specifically expressed by employing annealing control primer (ACP)-based GeneFishing polymerase chain reaction (PCR) from P. xuthus the larva. Using 120 arbitrary ACPs, we identified 24 differentially expressed genes (DEGs) that are up-regulated in response to injected LPS. Sequence analysis showed that 18 DEGs revelaed a high sequence similarity to the previously characterized genes of other insects, although 6 DEGs showed no significant similarity to any known genes. Among these inducible transcripts we found 8 putative immune-related genes including cecropin and attacin. Finally, we analysed the expression profiles of potential immune-related genes by RT-PCR and found all of them were considerably increased in the mRNA levels by LPS injection.
        74.
        2008.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, BaTiO3 thin films were grown by RF-magnetron sputtering, and the effects of a post-annealing process on the structural characteristics of the BaTiO3 thin films were investigated. For the crystallization of the grown thin films, post-annealing was carried out in air at an annealing temperature that varied from 500-1000˚C. XRD results showed that the highest crystal quality was obtained from the samples annealed at 600-700˚C. From the SEM analysis, no crystal grains were observed after annealing at temperatures ranging from 500 to 600˚C; and 80 nm grains were obtained at 700˚C. The surface roughness of the BaTiO3 thin films from AFM measurements and the crystal quality from Raman analysis also showed that the optimum annealing temperature was 700˚C. XPS results demonstrated that the binding energy of each element of the thin-film-type BaTiO3 in this study shifted with the annealing temperature. Additionally, a Ti-rich phenomenon was observed for samples annealed at 1000˚C. Depth-profiling analysis through a GDS (glow discharge spectrometer) showed that a stoichiometric composition could be obtained when the annealing temperature was in the range of 500 to 700˚C. All of the results obtained in this study clearly demonstrate that an annealing temperature of 700˚C results in optimal structural properties of BaTiO3 thin films in terms of their crystal quality, surface roughness, and composition.
        4,000원
        75.
        2008.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        1.5 μm-thick copper films deposited on silicon wafers were successfully bonded at 415˚C/25 kN for 40 minutes in a thermo-compression bonding method that did not involve a pre-cleaning or pre-annealing process. The original copper bonding interface disappeared and showed a homogeneous microstructure with few voids at the original bonding interface. Quantitative interfacial adhesion energies were greater than 10.4 J/m2 as measured via a four-point bending test. Post-bonding annealing at a temperature that was less than 300˚C had only a slight effect on the bonding energy, whereas an oxygen environment significantly deteriorated the bonding energy over 400˚C. This was most likely due to the fast growth of brittle interfacial oxides. Therefore, the annealing environment and temperature conditions greatly affect the interfacial bonding energy and reliability in Cu-Cu bonded wafer stacks.
        4,000원
        76.
        2008.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A 532 nm Nd-YAG laser was applied to crystallize amorphous Si thin films in order to evaluate the applicability of a Nd-YAG laser to low-temperature polycrystalline Si technology. The irradiation of a green laser was controlled during the crystallization of amorphous Si thin films deposited onto glass substrates in a sophisticated process. Raman spectroscopy and UV-Visible spectrophotometry were employed to quantify the degree of crystallization in the Si thin films in terms of its optical transmission and vibrational characteristics. The effectiveness of the Nd-YAG laser is suggested as a feasible alternative that is capable of crystallizing the amorphous Si thin films.
        3,000원
        77.
        2008.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Fe-aluminides have the potential to replace many types of stainless steels that are currently used in structural applications. Once commercialized, it is expected that they will be twice as strong as stainless steels with higher corrosion resistance at high temperatures, while their average production cost will be approximately 10% of that of stainless steels. Self-propagating, high-temperature Synthesis (SHS) has been used to produce intermetallic and ceramic compounds from reactions between elemental constituents. The driving force for the SHS is the high thermodynamic stability during the formation of the intermetallic compound. Therefore, the advantages of the SHS method include a higher purity of the products, low energy requirements and the relative simplicity of the process. In this work, a Fe-aluminide intermetallic compound was formed from high-purity elemental Fe and Al foils via a SHS reaction in a hot press. The formation of iron aluminides at the interface between the Fe and Al foil was observed to be controlled by the temperature, pressure and heating rate. Particularly, the heating rate plays the most important role in the formation of the intermetallic compound during the SHS reaction. According to a DSC analysis, a SHS reaction appeared at two different temperatures below and above the metaling point of Al. It was also observed that the SHS reaction temperatures increased as the heating rate increased. A fully dense, well-bonded intermetallic composite sheet with a thickness of 700 μm was formed by a heat treatment at 665˚C for 15 hours after a SHS reaction of alternatively layered 10 Fe and 9 Al foils. The phases and microstructures of the intermetallic composite sheets were confirmed by EPMA and XRD analyses.
        4,000원
        78.
        2008.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The effects of the deposition and annealing temperature on the structural, electrical and opticalproperties of Ag doped ZnO (ZnO:Ag) thin films were investigated. All of the films were deposited with a 2wt%Ag2O-doped ZnO target using an e-beam evaporator. The substrate temperature varied from room temperature(RT) to 250oC. An undoped ZnO thin film was also fabricated at 150oC as a reference. The as-grown films wereannealed in temperatures ranging from 350 to 650oC for 5h in air. The Ag content in the film decreased asthe deposition and the post-annealing temperature increased due to the evaporation of the Ag in the film.During the annealing process, grain growth occurred, as confirmed from XRD and SEM results. The as-grownfilm deposited at RT showed n-type conduction; however, the films deposited at higher temperatures showedp-type conduction. The films fabricated at 150oC revealed the highest hole concentration of 3.98×1019cm-3 anda resistivity of 0.347Ω·cm. The RT PL spectra of the as-grown ZnO:Ag films exhibited very weak emissionintensity compared to undoped ZnO; moreover, the emission intensities became stronger as the annealingtemperature increased with two main emission bands of near band-edge UV and defect-related greenluminescence exhibited. The film deposited at 150oC and annealed at 350oC exhibited the lowest value of Ivis/Iuv of 0.05.
        4,000원
        79.
        2008.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The electromagnetic (EM) wave absorption properties with a variation of crystallization annealing temperature have been investigated in a sheet-type absorber using the alloy powder. With increasing the annealing temperature the complex permeability (), permittivity () and power absorption changed. The EM wave absorber shows the maximum permeability and permittivity after the annealing at for 1 hour, and its calculated power absorption is above 80% of input power in the frequency range over 1.5 GHz.
        4,000원
        80.
        2007.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
          Forming central warehouses for a number of stores can save costs in the continuous review inventory model due to economy of scale and information sharing. In this paper, transportation costs are included in this inventory model. Hence, the tradeoff betw
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