• Progress in Superconductivity
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• 제1권1호
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• pp.31-35
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• 1999

We have fabricated and tested a simple circuit of the rapid single-flux-quantum(RSFQ) four-stage shift register using a single layer high-$T_c$ superconducting (HTS) $YBa_2Cu_3O_{7-x}$ (YBCO) thin film structure with 9 step-edge Josephson junctions. The circuit includes two read superconducting quantum interference devices(SQUID) and four stages. To establish a robust HTS RSFQ device fabrication process, we have focussed on the reproducible process of sharp and straight step-edge formation as well as the ratio of film thickness to step height, t/h. The spread of step-edge junction parameters was measured from each 13 junctions with t/h=1/3, 1/2, and 2/3 at various temperatures. We have demonstrated the simplified operation of the shift register at 65 K.

• Korean Journal of Materials Research
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• 제28권4호
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• pp.235-240
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• 2018

We propose a speedy two-step deposit process to form an Au electrode on hole transport layer(HTL) without any damage using a general thermal evaporator in a perovskite solar cell(PSC). An Au electrode with a thickness of 70 nm was prepared with one-step and two-step processes using a general thermal evaporator with a 30 cm source-substrate distance and $6.0{\times}10^{-6}$ torr vacuum. The one-step process deposits the Au film with the desirable thickness through a source power of 60 and 100 W at a time. The two-step process deposits a 7 nm-thick buffer layer with source power of 60, 70, and 80 W, and then deposits the remaining film thickness at higher source power of 80, 90, and 100 W. The photovoltaic properties and microstructure of these PSC devices with a glass/FTO/$TiO_2$/perovskite/HTL/Au electrode were measured by a solar simulator and field emission scanning electron microscope. The one-step process showed a low depo-temperature of $88.5^{\circ}C$ with a long deposition time of 90 minutes at 60 W. It showed a high depo-temperature of $135.4^{\circ}C$ with a short deposition time of 8 minutes at 100 W. All the samples showed an ECE lower than 2.8 % due to damage on the HTL. The two-step process offered an ECE higher than 6.25 % without HTL damage through a deposition temperature lower than $88^{\circ}C$ and a short deposition time within 20 minutes in general. Therefore, the proposed two-step process is favorable to produce an Au electrode layer for the PSC device with a general thermal evaporator.

• 한국벤처창업학회:학술대회논문집
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• 한국벤처창업학회 2007년도 춘계학술대회
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• pp.79-99
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• 2007

This paper evaluates the economic effect of the IT SoC Industrial Foundation Composition Project. The evaluation was done in three steps. The first step was to estimate the contribution effect of the fabless small and medium venture business' sales. The step includes interview with all the CEOs of the firms under the support of the Enterprise Incubation System, The second step was to apply input-output analysis and then estimate the production inducement effect. The last step was to compare the results of estimation with the costs of the project. We have concluded this project had achieved 6.3 times greater economic effect compared to the budget. The reason for the large economic effect is that the project provided various infrastructures to the small and medium venture businesses.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제17권7호
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• pp.793-796
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• 2004

In order to improve c-axis crystalline orientation and high perpendicular coercivity of deposited ${Co}_77{Cr}_20{Ta}_3$perpendicualr recording layer, Two step method was investigated using a Facing Targets Sputtering System(FTS). The ${\Delta\theta}_50$ of ${Co}_77{Cr}_20{Ta}_3$recording layer deposited on seedlayer prepared at Room Temperature was as low as $5^\circ$, while that of the recording layer without seedlayer was about 11$^{\circ}$. The Two-Step method using ${Co}_77{Cr}_20{Ta}_3$seedlayer prepared at Room Temperature was shown to be very effective in controling the c-axis orientation of ${Co}_77{Cr}_20{Ta}_3$ recording layer with thin thickness.

• Korean Journal of Materials Research
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• 제11권9호
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• pp.769-775
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• 2001

High quality PZT piezoelectric thin films were sputter- deposited on$ RuO_2$/$SiO_2$/Si substrates by using 2-step deposition method. As the first step, PZT seed layers were fabricated at a low temperature($475^{\circ}C$ ) to form a pure perovskite phase by reducing the volatility of Pb oxide. and then, as the second step, the PZT films were deposited at high temperatures ($530^{\circ}C$~$570^{\circ}C$) to reduce the defect density in the films. By this method, the pure perovskite phase was obtained at high deposition temperature range ($530^{\circ}C$~$570^{\circ}C$) and the superior electrical properties of PZT films were obtained on $RuO_2$substrate : 2Pr : 60$\mu$C/$\textrm{cm}^2$, $E_c: 60kV/cm, \;J_t: 10^{-6}A/cm^2\; at\; 250kV/cm$. The residual stress of PZT films fabricated by the 2-step deposition method was tensile and below 150MPa. It was attempted to control the residual stress in the PZT films by applying a negative bias to the substrate. As the amplitude of the substrate bias was increased, the residual tensile stress was slightly decreased, however, the ferroelectric properties of PZT films were degraded by ion bombardment.

• Preventive Nutrition and Food Science
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• 제4권4호
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• pp.246-250
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• 1999

This study was conducted to develop the fermentation kinetic modeling for the prediction of pH and acidity changes in kimchi at isothermal and nonisothermal fermentation temperatures(0~15$^{\circ}C$) and salt concentrations(1.5~4.0%) using the traditional two-step method and alternative one-step method. The calculations of the two-step method of pH and acidity change during fermentation followed the pattern of the first order and zero order, respectively. The reaction rate constant of pH by the first order was increased from 0.008 {TEX}$day^{-1}${/TEX} to 0.017 {TEX}$day^{-1}${/TEX} by increasing the temperature from $0^{\circ}C$ to 15$^{\circ}C$ at 2.75% of salt concentration, and was decreased from 0.013 {TEX}$day^{-1}${/TEX} to 0.010 {TEX}$day^{-1}${/TEX} by increasing the salt concentration from 1.5% to 4.0% at 5$^{\circ}C$. For the pH and acidity of Kimchi, the zero order had a higher correlation than the first order to the estimate of the kinetics parameters by the one-step method. The {TEX}$E_{a}${/TEX} ranges of pH and acidity were 61.057~66.086 and 62.417~68.772 kJ/mole with different temperatures and salt concentrations. This one-step method had smaller and more realistic estimates of error(p〈0.05). The effective temperatures, {TEX}$T_{eff}${/TEX}, with 0~15$^{\circ}C$ of square function type of 12 hr intervals were 12.85, 11.48 and 12.46$^{\circ}C$ as increasing the salt concentration, 1.50, 2.75 and 4.00%, respectively. The {TEX}$T_{eff}${/TEX} were higher values than the mean temperature(7.5$^{\circ}C$).

• The Journal of Korean Society for Radiation Therapy
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• 제28권1호
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• pp.7-16
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• 2016

Purpose : This study aimed to compare and evaluate between the efficiency of two respective devices, 3D-bolus and step-bolus when the devices were used for the treatment of patients whose chest walls were required to undergo the electron beam therapy after the surgical procedure of modified radical mastectomy, MRM. Materials and Methods : The treatment plan of reverse hockey stick method, using the photon beam and electron beam, had been set for six breast cancer patients and these 6 breast cancer patients were selected to be the subjects for this study. The prescribed dose of electron beam for anterior chest wall was set to be 180 cGy per treatment and both the 3D-bolus, produced using 3D printer(CubeX, 3D systems, USA) and the self-made conventional step-bolus were used respectively. The surface dose under 3D-bolus and step-bolus was measured at 5 measurement spots of iso-center, lateral, medial, superior and inferior point, using GAFCHROMIC EBT3 film (International specialty products, USA) and the measured value of dose at 5 spots was compared and analyzed. Also the respective treatment plan was devised, considering the adoption of 3D-bolus and stepbolus and the separate treatment results were compared to each other. Results : The average surface dose was 179.17 cGy when the device of 3D-bolus was adopted and 172.02 cGy when step-bolus was adopted. The average error rate against the prescribed dose of 180 cGy was -(minus) 0.47% when the device of 3D-bolus was adopted and it was -(minus) 4.43% when step-bolus was adopted. It was turned out that the maximum error rate at the point of iso-center was 2.69%, in case of 3D-bolus adoption and it was 5,54% in case of step-bolus adoption. The maximum discrepancy in terms of treatment accuracy was revealed to be about 6% when step-bolus was adopted and to be about 3% when 3D-bolus was adopted. The difference in average target dose on chest wall between 3D-bolus treatment plan and step-bolus treatment plan was shown to be insignificant as the difference was only 0.3%. However, to mention the average prescribed dose for the part of lung and heart, that of 3D-bolus was decreased by 11% for lung and by 8% for heart, compared to that of step-bolus. Conclusion : It was confirmed through this research that the dose uniformity could be improved better through the device of 3D-bolus than through the device of step-bolus, as the device of 3D-bolus, produced in consideration of the contact condition of skin surface of chest wall, could be attached to patients' skin more nicely and the thickness of chest wall can be guaranteed more accurately by the device of 3D-bolus. It is considered that 3D-bolus device can be highly appreciated clinically because 3D-bolus reduces the dose on the adjacent organs and make the normal tissues protected, while that gives no reduction of dose on chest wall.

• Korean Chemical Engineering Research
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• 제54권1호
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• pp.1-5
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• 2016

For obtain fermentable sugar, we conducted acid hydrolysis with lignocellulosic biomass without enzyme. The lignocellulosic biomass used pinus rigida and Palm residues (EFB; empty fruit bunches). In the acid hydrolysis, we consider the hydrolysis condition to reduce a denatured sugar. So this study was conducted 2-step acid hydrolysis. First-step hydrolysis used high concentration (72 wt%) sulfuric acid at $80^{\circ}C$. At the condition, we obtained 11.49 wt%, 32 wt% glucose conversion for pinus rigida and EFB. After the step, the liquor was dilute until 9~15 wt% acid concentration and conducted second hydrolysis at $50{\sim}120^{\circ}C$. In the second hydrolysis, we obtained maximum glucose conversion (pinus rigida 86.8 wt% (39 g/L) and EFB 95.3 wt% (32.4 g/L)) at 9 wt% acid concentration and $120^{\circ}C$ for 80 min. All samples through the process are analyzed on the basis of mass balance.

• Journal of the Korean Crystal Growth and Crystal Technology
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• 제12권6호
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• pp.311-316
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• 2002

Two different approaches, namely two-step deposition process and Bias-Enhanced Nucleation (BEN) technique have been examined for deposition of high quality diamond thin film on polycrystalline Ni which has low chemical activity with the carbon neutrals provided from the $CH_4/H_2$mixtures. A two-step deposition process, consisted of pre-deposition of soot layer at lower temperatures and subsequent deposition at higher temperature condition, has been developed to deposit diamond layer directly on Ni substrate. Diamond particles were observed after deposition step at $925^{\circ}C$ for 5 hours and those particles seem to be nucleated from the soot layer pre-deposited at lower temperatures ($810^{\circ}C$). Diamond particles of a substantial size were found on Ni substrate after biasing -220 V for 10 minutes and subsequent deposition for 2 hours while no diamond particles were observed under the conditions without applied bias.

• Journal of the Korean Society for Precision Engineering
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• 제19권12호
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• pp.185-193
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• 2002

Most of NC machines are operated by Is06983 standard called G-code, which was developed in the early days of machine tools. This G-code limits hardware performance of the currently developed high-performance hardware & machine tools. By describing only movements of tool, almost all of information of previous production departments is lost, and the machining department cannot exchange information with other departments. For adjusting new hardware environment and direct communication of CNC machines with CAD/CAM software, ISO 14649, STEP -NC is researched. This new standard stores CAD/CAM information as well as operation commands of CNC machines. In this research, the new CNC machine operated by STEP-NC was built and tested. Unlike other STEP-NC milling machines, this system uses the STEP-NC file in form of XML as data input. It makes possible for STEP-NC machines to exchange information to other databases using XML. The mentioned system of this paper loads the XML file, analyzes it, makes tool paths of two5D features with information of STEP-NC, and machines automatically without making G-code. All of software is programmed with Visual C＋＋, and the milling machine is made with table milling machine, step motors, and motion control board for PC that can be directly controlled by C＋＋ commands. All modules of software and hardware were independent, it allows convenient for substitution and expansion of the milling machine. The example 1 in ISP14649-11 that had all information about geometry and machining and the example 2 that has only geometry and tool information were used to test automatic machining by the open-architecture milling machine.