• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.2
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• pp.125-129
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• 2005

Two kinds of physical treatments were examined for the analysis both of intrinsic surface and interior nature of CuInS $e_2$[CIS] and CuGaS $e_2$[CGS] films grown in separated systems. For the first method, a selenium protection layer which was immediately deposited after the growth of the CIS was investigated. The Se cap layer protects CISe surface from oxidation and contamination during the transport under ambient atmosphere. The Se cap was removed by thermal annealing at temperature above 15$0^{\circ}C$. After the decapping treatment at 2$25^{\circ}C$ for 60 min, ultraviolet photoemission and inverse photoemission measurements of the CIS film showed that its valence band maximum(VBM) and conduction band minimum (CBM) are located at 0.58 eV below and 0.52 eV above the Fermi level $E_{F}$, respectively. For the second treatment, an Ar ion beam etching was exploited. The etching with ion kinetic energy $E_{k}$ above 500 eV resulted in broadening of photoemission spectra of core signals and occasional development of metallic feature around $E_{F}$. These degradations were successfully suppressed by decreasing $E_{k}$ below 400 eV. CGS films etched with the beam of $E_{k}$ = 400 eV showed a band gap of 1.7 eV where $E_{F}$ was almost centered.st centered.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.183-183
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• 2012

In the era of 45 nm or beyond technology, conventional etch mask using photoresist showed its limitation of etch mask pattern collapse as well as pattern erosion, thus hard mask in etching became necessary for precise control of etch pattern geometry. Currently available hard mask materials are amorphous carbon and polymetric materials spin-on containing carbon or silicon. Amorphous carbon layer (ACL) deposited by PECVD for etch hard mask has appeared in manufacturing, but spin-on carbon (SOC) was also suggested to alleviate concerns of particle, throughput, and cost of ownership (COO) [1]. SOC provides some benefits of reduced process steps, but it also faced with wiggling on a sidewall profile. Diamond like carbon (DLC) was also evaluated for substituting ACL, but etching selectivity of ACL was better than DLC although DLC has superior optical property [2]. Developing a novel material for pattern hard mask is very important in material research, but it is also worthwhile eliminating a potential issue to continuously develop currently existing technology. In this paper, we investigated in-situ dry-cleaning (ISD) monitoring of ACL coated process chamber. End time detection of chamber cleaning not only provides a confidence that the process chamber is being cleaned, but also contributes to minimize wait time waste (WOW). Employing Challenger 300ST, a 300mm ACL PECVD manufactured by TES, a series of experimental chamber cleaning runs was performed after several deposition processes in the deposited film thickness of $2000{\AA}$ and $5000{\AA}$. Ar Actinometry and principle component analysis (PCA) were applied to derive integrated and intuitive trace signal, and the result showed that previously operated cleaning run time can be reduced by more than 20% by employing real-time monitoring in ISD process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.4
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• pp.316-322
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• 2001

Cathode materials $LiMn_{2-y}$$M_{y}$ $O_4$(M=Zn and Mg) were obtained by reacting the mixture of LiOH.$H_2O$, Mn $O_2$ and MgO ar ZnO at 80$0^{\circ}C$ for 36h in an air atmosphere. These materials showed an extended cycle life in lithium-anode cells working at room temperatue in a 3.0 to 4.3V potential window. Among these materials, LiM $n_{1.9}$M $g_{0.1}$ $O_4$ showed the best cycle performance in terms of the capacity and cycle life. The discharge capacities of the cathode for the Li/LiM $n_{1.9}$ $M_{0.1}$ $O_4$ cell at the 1st cycle and at the 70th cycle were about 120 and 105mAh/g, respectively. This cell capacity is retained by 88% after 70th cycle. In cyclic voltammetry measurement, all cells revealed tow oxidation peaks and reduction peaks. However, Li/$LiMn_{2-y}$$M_{y}$ $O_4$ cell substituted with Zn and Mg showed new reaction peak during reduction reaction.eaction.ion.ion.

• Publications of The Korean Astronomical Society
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• v.21 no.2
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• pp.51-59
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• 2006

We have successfully developed the KASI (Korea Astronomy and Space Science Institute) Solar Imaging Spectrograph (KSIS), which has been originally upgraded from the KASI solar spectrograph that was able to record solar spectra for a given slit region and to inspect the response function of narrow band filters. A prototype KSIS was developed in 2004 by using a scanning mirror in front of the spectrograph slit and a SBIG ST-8XE CCD camera. Its main disadvantage is that it took a long time (about 13 minutes) to scan a whole active region. In this work, we have upgraded the KSIS by installing a much faster Dalsa 1M15 CCD camera, which gives a data acquisition time of about 2.5 minutes. The software for KSIS was also improved for the new CCD camera on the basis of component-based development method. We have successfully made a test observation for a simple and small active region (AR10910) using the improved KSIS system. Our observations show that H-alpha images for several wavelengths have typical features in a sunspot as well as a H-alpha centerline image is quite similar to a BBSO H-alpha image, demonstrating the capability of the KSIS system.

• Journal of Chest Surgery
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• v.42 no.6
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• pp.777-780
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• 2009

We reported here on 2 cases of aortic regurgitation (AR) that were due to avulsion of the aortic valve commissure. Aortic valvuloplasty was attempted in both cases. In the 1st case, valvuloplasty was performed with reattaching the commissure using the 5-0 polypropylene continuous suture technique. However, aortic regurgitation recurred and this lead to reoperation on the postoperative $14^{th}$ day. The intraoperative finding revealed a completely re-detached commissure that required mechanical valve replacement. In the second case, we attempted to reattach the commissure using pledgetted multiple transverse mattress sutures with 5-0 polypropylene. Because the leaflet coaptation was incomplete, the aortic valve was replaced with a tissue valve.

• Journal of Korea Water Resources Association
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• v.35 no.6
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• pp.763-777
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• 2002

The objective of this study is to develop computer simulation model that produces precipitation patterns from stochastic model. The hourly precipitation process consists of the precipitation occurrence and precipitation amounts. In this study, an event cluster model developed by Lee and Lee(2002) is used to describe the occurrence process of events, and the hourly precipitation amounts within each event is described by a nonstationary form of a first-order autoregressive process. The complete stochastic model for hourly precipitation is fitted to historical precipitation data by estimating the model parameters. An analysis of historical and simulated hourly precipitation data for Seoul indicates that the stochastic model preserves many of the features of historical precipitation. The autocorrelation coefficients of the historical and simulated data are nearly identical except for lags more than about 3 hours. The precipitation intensity, duration, marginal distributions, and conditional distributions for event characteristics for the historical and simulated data showed in general good agreement with each other.

• Korean Journal of Materials Research
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• v.7 no.3
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• pp.213-217
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• 1997

AOhf(Hcousto-r)l)tic niodulator) with :!OOlIiz freclucncl- and Sfi(;(Seconrl harmonic generation) green lasel-Lvith 53% nm wavelength were used for Il\'IIII~Dii.it,ii v~ilco disk recorder) FOI rhe appli~aptin of high densit]. optical recording, a high po\ver I ~ c r is r c ~ ~ l i ~ i l - u l ic I !tic. s\-sti,m a n d optic.,~I io;iting l,t)c>rs of each optical device must have a high laser damage threshoid hie rn;itie ant] retlwtive coatings on a $TeO_{2}$ singlc crystal. which is used as an acoustooptic material, by E-beam evaporation method. Laser damage threshold \vas nicdsureci hy Ar laser with the input power oi 0.55LV 1,aser damage threiholti 01 $ZrO_{2}$ and $SiO_{2}$. filn-is were higher than $AI_{2}O_{3}$ f i l m U'e also investigated a long--tern1 stability of the output po\ver of St{(; green laser

• The Korean Journal of Nuclear Medicine
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• v.30 no.1
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• pp.104-111
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• 1996

We did Tc-99m sestamibi myocardial perfusion SPECT in 36 patients with acute myocardial infarction when they arrived at the emergency room. And we compared myocardial perfusion images with ECG findings. Then we obtained the follows. The myocardial infarction by the obstruction of left coronary descending artery and right coronary artery showed a good concordance in the diagnosis and infarction site between myocardial perfusion images and ECG findings. The 7 patients with myocardial infarction by a left circumflex coronary artery showed a perfusion defect in the lateral wall in myocardial perfusion SPECT images. But 4 patients of them showed ST segment elevation, 2 patients showed ST depression and 1 patient showed normal ECG findings. The diagnostic sensitivity of Tc-99m sestamibi myocardial perfusion SPECT was 100% by a qualified analysis. The perfusion defect site in the myocardial perfusion SPECT were corresponded with the infarct related coronary artery in 31 patients which was diagnosed by coronary angiograpy. The size of perfusion defect in the po1ar map was $31{\pm}18%(M{\pm}SD)$, in the myocardial infarction with left anterior descending coronary arery obstruction, $31{\pm}13% (M{\pm}SD)$ in the myocardial infarction with right coronary artery obstruction and $25{\pm}5.9%(M{\pm}SD)$ in the myocardial infarction with left circumflex coronary artery obstruction. We concluded that emergency myocardial perfusion SPECT images are useful in the diagnose of myocardial infarction and it's very useful when we are difficult to diagnose with ECG like as lateral wall infarction or left bundle branch block.

• Korean Journal of Food Science and Technology
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• v.37 no.6
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• pp.873-881
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• 2005

This study was conducted to improve the properties of frozen dough foods (buns and noodles etc.) on the quality deterioration with microwave oven cooking. Microwave is a useful cooking method, but it quickly takes moisture from food surface and makes lowering food quality abruptly. For improvement of these problems, mixing doughs with addition of various additives of 34 types manufactured respectively; starches, modified starches, gums and emulsifiers etc. Each mixing dough produced in sheet type $(30{\times}30{\times}1mm)$ and steamed them, was quickly froze at $-70^{\circ}C$ and packed with polyethylene. Packed samples kept at $-20^{\circ}C$ for 48 hours. After they were steam or microwave treatment packed or non-packed with polyethylene, studied for improvement effects of quality as sensory evaluation and selected 6 type additives; modified starches (TA, ST), gums (AR, GA) and emulsifiers (E, S1) as improvement agent. Because moisture loss from microwave oven cooking leads to quality deterioration of frozen dough foods, additive, such as including starches, modified starch, gums, and emusifiers were added to improve dough properties. Amylogram, scanning electron microscopy, textural analysis, and differential scanning calorimetry revealed addition of additives improved textural properties including surface-hardening of frozen dough foods compared to the control.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.4
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• pp.228-232
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• 2006

Purpose: electrophilic $^{18}F(T_{1/2}=110\;min)$ radionuclide in the form of $[^{18}F]F_2$ gas is of great significance for labeling radiopharmaceuticals for positron omission tomography (PET). However, its production In high yield and with high specific radioactivity is still a challenge to overcome several problems on targetry. The aim of the present study was to develop a method suitable for the routine production of $[^{18}F]F_2$ for the electrophilic substitution reaction. Materials and Methods: The target was designed water-cooled aluminum target chamber system with a conical bore shape. Production of the elemental fluorine was carried out via the $^{18}O(p,n)^{18}F$ reaction using a two-step irradiation protocol. In the first irradiation, the target filled with highly enriched $^{18}O_2$ was irradiated with protons for $^{18}F$ production, which were adsorbed on the inner surface of target body. In the second irradiation, the mixed gas ($1%[^{19}F]F_2/Ar$) was leaded into the target chamber, fellowing a short irradiation of proton for isotopic exchange between the carrier-fluorine and the radiofluorine absorbed in the target chamber. Optimization of production was performed as the function of irradiation time, the beam current and $^{18}O_2$ loading pressure. Results: Production runs was performed under the following optimum conditions: The 1st irradiation for the nuclear reaction (15.0 bar of 97% enriched $^{18}O_2$, 13.2 MeV protons, 30 ${\mu}A$, 60-90 min irradiation), the recovery of enriched oxygen via cryogenic pumping; The 2nd irradiation for the recovery of absorbed radiofluorine (12.0 bar of 1% $[^{19}F]fluorine/argon$ gas, 13.2 MeV protons, 30 ${\mu}A$, 20-30 min irradiation) the recovery of $[^{18}F]fluorine$ for synthesis. The yield of $[^{18}F]fluorine$ at EOB (end of bombardment) was achieved around $34{\pm}6.0$ GBq (n>10). Conclusion: The production of $^{18}F$ electrophilic agent via $^{18}O(p,n)^{18}F$ reaction was much under investigation. Especially, an aluminum gas target was very advantageous for routine production of $[^{18}F]fluorine$. These results suggest the possibility to use $[^{18}F]F_2$ gas as a electrophilic substitution agent.