• Journal of Powder Materials
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• v.28 no.1
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• pp.25-30
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• 2021

The surface of silicon dummy wafers is contaminated with metallic impurities owing to the reaction with and adhesion of chemicals during the oxidation process. These metallic impurities negatively affect the device performance, reliability, and yield. To solve this problem, a wafer-cleaning process that removes metallic impurities is essential. RCA (Radio Corporation of America) cleaning is commonly used, but there are problems such as increased surface roughness and formation of metal hydroxides. Herein, we attempt to use a chelating agent (EDTA) to reduce the surface roughness, improve the stability of cleaning solutions, and prevent the re-adsorption of impurities. The bonding between the cleaning solution and metal powder is analyzed by referring to the Pourbaix diagram. The changes in the ionic conductivity, H2O2 decomposition behavior, and degree of dissolution are checked with a conductivity meter, and the changes in the absorbance and particle size before and after the reaction are confirmed by ultraviolet-visible spectroscopy (UV-vis) and dynamic light scattering (DLS) analyses. Thus, the addition of a chelating agent prevents the decomposition of H2O2 and improves the life of the silicon wafer cleaning solution, allowing it to react smoothly with metallic impurities.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.7
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• pp.2345-2358
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• 2022

This paper presents a method to generate stained-glass animation from video inputs. The method initially segments an input video volume into several regions considered as fragments of glass by mean-shift segmentation. However, the segmentation predominantly results in over-segmentation, causing several tiny segments in a highly textured area. In practice, assembling significantly tiny or large glass fragments is avoided to ensure architectural stability in stained glass manufacturing. Therefore, we use low-frequency components in the segmentation to prevent over-segmentation and subdivide segmented regions that are oversized. The subdividing must be coherent between adjacent frames to prevent temporal artefacts, such as flickering and the shower door effect. To temporally subdivide regions coherently, we obtain a panoramic image from the segmented regions in input frames, subdivide it using a weighted Voronoi diagram, and thereafter project the subdivided regions onto the input frames. To render stained glass fragment for each coherent region, we determine the optimal match glass fragment for the region from a dataset consisting of real stained-glass fragment images and transfer its color and texture to the region. Finally, applying lead came at the boundary of the regions in each frame yields temporally coherent stained-glass animation.

• The Korean Journal of Physiology
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• v.7 no.2
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• pp.1-8
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• 1973

Though it has been reported by Clements et al. and Avery et al. that the activity of the pulmonary surfactant can be altered by the temperature changes, a conclusive evidence of the effects of temperature on the surfactant system of the lung is yet to come. In the present study, an attempt was made to observe possible effects of a few different degrees of temperature on the activity of the pulmonary surfactant of the rabbit in vivo and in vitro. The rabbit was sacrificed by blood shedding and both lungs were completely removed. The lung washings, obtained by gently lavaging the left lung with saline, was placed at 1) 4C for 1, 5, 10, 15, 30 and 40 days, and 2) 20C for 1, 2, 3, 4, 5 and 7 days for in vitro experiment. For in vivo experiment, the rabbit was placed at 4C for 4, 8, 12 and 24 hours, and the lung lavage was prepared as described above in the in vitro experiment. Tension-area (T-A) diagram of the lung lavage was recorded automatically by a modified. Langmuir-Wilhelmy balance with a synchronized recording system. The surface tensions thus obtained were compared with those of the normal rabbit, and the results are summarized as follows: 1. The maximal surface tension, minimal surface tension and stability index of the normal rabbit lung lavage were $52.5{\pm}2.3\;dynes/cm,\;4.9{\pm}2.3\;dynes/cm$ and 1.65, respectively. 2. In the group where the lung lavage was placed at 4C in vitro, the maximal and minimal surface tensions, and stability index did not show any noticeable changes comparing with the normal values up to 30 days. On the 40th day of the experiment, a tendency of a slight increase in the surface tensions was observed but the change was not significant. 3. When the lung lavage was placed at 20 C in vitro, the maximal surface tension did not show any appreciable change comparing with the normal except on the 7 th day with a slight increase. The minimal surface tension showed an increased value from the 2nd day, and on the 5 th and 7 th experimental day, markedly increased value was observed. The stability index, on the other hand. showed a marked decrease throughout the entire experiment with the value of 0.71 and 0.53 on the 5th and 7 th day, respectively. 4. In the group where the rabbit was placed at 4 C in vivo, the maximal surface tensions and stability index of the lung lavage showed little change from the normal. The minimal surface tension at 12 experimental hour showed a slight increase, but it returned to the normal value at 24 hour.

• The Journal of Engineering Geology
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• v.9 no.3
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• pp.207-225
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• 1999

Twenty water samples (eleven groundwater and nine geothermal water samples) were collected to elucidate hydrogeochemical characteristics of the groundwater and geothermal water in the Dongrae hot-spring area and its vicinity. Major and minor elements were analyzed for ground and geothermal water samples. Physicochemical properties of the groundwater and the geothermal water were examined and chemical composition of the two waters were compared. Factor and correlation analyses were carried out to simplify the physicochemical data into grouping some factors and to find interaction between them. The groundwaters belong to $Ca-HCO_3$ type, while the geothermal waters belong to Na-Cl type. The Na and Cl concentrations in the Dongrae hot-spring area are higher than those of other granite areas in South Korea. The Na/Cl weight ratio ranges from 0.7 to 1.3 for the geothermal waters. On the phase stability diagram groundwaters fall effectively in the field of stability of kaolinite, while geothermal waters fall in the stability field of microcline or kolinite depending on the chemical composition system. Based on the Na-K, Na-K-Ca and Na-K-Ca-Mg geothermometers, the geothermal reservoir is estimated to have equilibrium temperature between 115 and $145^{\circ}C$.

• Journal of Internet Computing and Services
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• v.23 no.6
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• pp.27-37
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• 2022

Virtual private network (VPN) services are used in various environments related to national security, such as defense companies and defense-related institutions where digital communication environment technologies are diversified and access to network use is increasing. However, the number of cyber attacks that target vulnerable points of the VPN has annually increased through technological advancement. Thus, this study identified security requirements by performing STRIDE threat modeling to prevent potential and new vulnerable points that can occur in the VPN. STRIDE threat modeling classifies threats into six categories to systematically identify threats. To apply the proposed security requirements, this study analyzed functions of the VPN and formed a data flow diagram in the VPN service process. Then, it collected threats that can take place in the VPN and analyzed the STRIDE threat model based on data of the collected threats. The data flow diagram in the VPN service process, which was established by this study, included 96 STRIDE threats. This study formed a threat scenario to analyze attack routes of the classified threats and derived 30 security requirements for each element of the VPN based on the formed scenario. This study has significance in that it presented a security guideline for enhancing security stability of the VPN used in facilities that require high-level security, such as the Ministry of National Defense (MND).

• Journal of the Mineralogical Society of Korea
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• v.15 no.3
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• pp.161-169
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• 2002

high pressure and temperature conditions. However, those results are not consistent with one another, and phase boundary between ilmenite and perovskite phases determined only from the quenching method may be not so reliable at all. Therefore, in-situ high pressure-temperature (hP-T) X-ray diffraction measurements were performed up to 19 GPa and $700^{\circ}C$ in a large volume press apparatus using synchrotron radiation. Experimental results show that perovskite phase is stable at pressures above 16 GPa, and transforms back to $LiNbO_3$phase near 15 CPa at room temperature, and that the perovskite-ilmenite transition is back and forth near 15 CPa at $500^{\circ}C$. LiNbO$_3$phase transforms to ilmenite at 13 CPa and $300^{\circ}C$ and at 10.8 CPa and $400^{\circ}C$, respectively. These data indicate that $LiNbO_3$phase may have a stability region in the hP-T phase diagram and that the perovskite-ilmenite phase boundary would be quite different from that previously reported.

• Journal of Pharmaceutical Investigation
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• v.27 no.1
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• pp.29-38
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• 1997

Precipitation was formed during the preparation of decoction from a mixture of Scutellariae Radix and Coptidis Rhizoma. Baicalin and berberine were identified in this coprecipitated product (CPP) and these components were the active ingredients of two herbal medicine. We extracted respectively crude baicalin and berberine in Scutellariae Radix and Coptidis Rhizoma and prepared coprecipitate of crude baicalin-berberine. To increase the stability and bioavailability of coprecipitate of crude baicalin-berberine(CBB), which is slightly soluble drug, its inclusion complex was prepared and studied in this experiment. Inclusion complex of CBB with ${\beta}-cyclodextrin(CBB-{\beta}-CD)$ was prepared by freeze drying method and its characteristics were ascertained by means of solubility test, differential thermal analysis(DTA) and scanning electron microscope(SEM). The type of $CBB-{\beta}-CD$ is classified as $A_L-type$ on phase solubility diagram, and the stoichiometric ratio of CBB(baicalin in CBB) : ${\beta}-CD$ complex is 1:1 and formation constant is 151 $M^-1$. The solubility, dissolution, in situ absorption and serum concentration of $CBB-{\beta}-CD$ were significantly increased when compared to CBB. Therefore enhanced bioavailability of CBB by inclusion complexation with ${\beta}-cyclodextrin$ might be useful for dosage form design of active ingredients of two herbal medicine.

• Journal of Energy Engineering
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• v.24 no.3
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• pp.6-12
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• 2015

The welding technology has been used in almost all industries such as automotive, shipbuilding, power plants and industrial machinery. In this study, the design and implementation of PLC $CO_2$ welding automation system were investigated. For these purposes, the structure analysis for driving supporter was performed and specification of automatic voltage regulator, mutual interface of system and circuit diagram were designed in order to contrive power-saving system. As the results, the stability of design for driving supporter could be convinced by numerical analysis and PLC automatic welding system was suitable for welding automation of structural-manufacturing factory capable of producing various and small amount products. Therefore, it was confirmed that PLC $CO_2$ welding automation system could contribute to productivity, stable quality and power-saving.

• International Journal of Aeronautical and Space Sciences
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• v.12 no.1
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• pp.57-62
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• 2011

The effects of swirl chamber's diameter and length on injector's dynamic characteristics were investigated through an experimental study. A mechanical pulsator was installed in front of the manifold of a swirl injector which produces pressure oscillations in the feed line. Pressure in the manifold, liquid film thickness in the orifice and the pressure in the orifice were measured in order to understand the dynamic characteristic of the simplex swirl injector with varying geometry. A direct pressure measuring method (DPMM) was used to calculate the axial velocity of the propellant in the orifice and the mass flow rate through the orifice. These measured and calculated values were analyzed to observe the amplitude and phase differences between the input value in the manifold and the output values in the orifice. As a result, a phase-amplitude diagram was obtained which exhibits the injector's response to certain pressure fluctuation inputs. The mass flow rate was calculated by the DPMM and measured directly through the actual injection. The effect of mean manifold pressure change was insignificant with the frequency range of manifold pressure oscillation used in this experiment. Mass flow rate was measured with the variation of injector's geometries and amplitude of the mass flow rate was observed with geometry and pulsation frequency variation. It was confirmed that the swirl chamber diameter and length affect an injector's dynamic characteristics. Furthermore, the direction of geometry change for achieving dynamic stability in the injector was suggested.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.5
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• pp.13-26
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• 1999

This paper presents a metric that can guide to optimal circuit models for interconnects among various models, given interconnect parameters and operating environment. To get this goal, we categorize interconnects into RC~c1ass and RLC-c1ass model domains based on the quantitative modeling error analysis using total resistance, inductance and capacitance of interconnects as well as operating frequency. RC~c1ass circuit models, which include most on~chip interconnects, can be efficiently analyzed by using the model~order reduction techniques. RLC-c1ass circuit models are constructed using one of three candidates, ILC(Iterative Ladder Circuit) macromodels, MC(Method of Characteristics) macromodels, and state-based convolution method, the selection process of which is based upon the allowable modeling error and electrical parameters of interconnects. We propose the model domain diagram leading to optimal circuit models and the division of model domains has been achieved considering the simulation cost of macromodels under the environmental assumption of the general purpose circuit simulator such as SPICE. The macromodeling method presented in this paper keeps the passivity of the original interconnects and accordingly guarantees the unconditional stability of circuit models.