• 한국전기전자재료학회논문지
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• 제21권8호
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• pp.687-694
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• 2008

This paper is focused on the improvement of MOS device reliability related to deuterium process. The injection of deuterium into the gate oxide film was achieved through two kind of method, high-pressure annealing and low-energy implantation at the back-end of line, for the purpose of the passivation of dangling bonds at $SiO_2/Si$ interface. Experimental results are presented for the degradation of 3-nm-thick gate oxide ($SiO_2$) under both negative-bias temperature instability (NBTI) and hot-carrier injection (HCI) stresses using P and NMOSFETs. Annealing process was rather difficult to control the concentration of deuterium. Because when the concentration of deuterium is redundant in gate oxide excess traps are generated and degrades the performance, we found annealing process did not show the improved characteristics in device reliability, compared to conventional process. However, deuterium ion implantation at the back-end process was effective method for the fabrication of the deuterated gate oxide. Device parameter variations under the electrical stresses depend on the deuterium concentration and are improved by low-energy deuterium implantation, compared to conventional process. Our result suggests the novel method to incorporate deuterium in the MOS structure for the reliability.

• 한국산업보건학회지
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• 제15권1호
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• pp.8-18
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• 2005

Adsorption capacity for the charcoal were tasted in this study to verify the performance of them for the use of the sampling media in industrial hygiene field. Two set of experiments were conducted. The first experiment was to test performance of the tested charcoal tube that were assembled in the laboratory with the use of the GR grade charcoal. The other tests were investigate the adsorption capacity of the charcoal tested in this study and charcoals embedded in the commercial charcoal tubes. Known air concentration samples for benzene, toluene, and o-xylene were prepared by the dynamic chamber. 1. At low air concentration levels (0.1${\times}$TLV), there was no significant differences between the tested charcoal tubes and the SKC charcoal tubes. This implies that there is no defect with the adsorption capacity of the charcoal. 2. At high concentration with 60 minutes sampling, the breakthrough were found only in the tested charcoal while no breakthrough were shown in the SKC charcoal. 3. From the breakthrough tests for the charcoal, the micropore volume(Wo) were calculated by the curve fitting with the use of Dubinin/Radushkevich(D/R) adsorption isotherm equation. The calculated values were 0.687cc/g for SKC, 0.504cc/g for Sensidyne, and 0.419cc/g for the tested charcoal(Aldrich). 4. Adsorption capacities were obtained from the isotherm curves shown adsorption capacities at several levels of the challenge concentration. All range of the air concentration concerned in industrial hygiene, the SKC charcoal showed approximately two times of adsorption capacity compared to the tested charcoal.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.327-327
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• 2009

ZnO with a large band gap (~3.37 eV) and exciton binding energy (~60 meV), is suitable for optoelectronic applications such as ultraviolet (UV) light emitting diodes (LEDs) and detectors. However, the ZnO-based p-n homojunction is not readily available because it is difficult to fabricate reproducible p-type ZnO with high hall concentration and mobility. In order to solve this problem, there have been numerous attempts to develop p-n heterojunction LEDs with ZnO as the n-type layer. The n-ZnO/p-GaN heterostructure is a good candidate for ZnO-based heterojunction LEDs because of their similar physical properties and the reproducible availability of p-type GaN. Especially, the reduced lattice mismatch (~1.8 %) and similar crystal structure result in the advantage of acquiring high performance LED devices. In particular, a number of ZnO films show UV band-edge emission with visible deep-level emission, which is originated from point defects such as oxygen vacancy, oxygen interstitial, zinc interstitial[1]. Thus, defect-related peak positions can be controlled by variation of growth or annealing conditions. In this work, the undoped ZnO film was grown on the p-GaN:Mg film using RF magnetron sputtering method. The undoped ZnO/p-GaN:Mg heterojunctions were annealed in a horizontal tube furnace. The annealing process was performed at $800^{\circ}C$ during 30 to 90 min in air ambient to observe the variation of the defect states in the ZnO film. Photoluminescence measurements were performed in order to confirm the deep-level position of the ZnO film. As a result, the deep-level emission showed orange-red color in the as-deposited film, while the defect-related peak positions of annealed films were shifted to greenish side as increasing annealing time. Furthermore, the electrical resistivity of the ZnO film was decreased after annealing process. The I-V characteristic of the LEDs showed nonlinear and rectifying behavior. The room-temperature electroluminescence (EL) was observed under forward bias. The EL showed a weak white and strong yellowish emission colors (~575 nm) in the undoped ZnO/p-GaN:Mg heterojunctions before and after annealing process, respectively.

• 한국의학물리학회지:의학물리
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• 제5권2호
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• pp.3-12
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• 1994

$Na^{+}$ 이온을 주입시킨 후, $^{17}$ Cs 감마선으로 조사된 $Al_2$O$_3$ 및, $Na^{+}$ 이 주입된 $Al_2$O$_3$의 열자극 발광을 340K～620K의 온도 구간에서 측정하였다. $Na^{+}$ 이온을 주입시킨 후, $^{137}$Cs 감마선으로 조사된 $Al_2$O$_3$의 열자극 발광 곡선은 415K, 452K, 508K, 및 568K에서 TL peak를 가지는 곡선으로 분해되었다. $Na^{+}$ 이온 주입 후 $^{137}$Cs 감마선 조사된 $Al_2$O$_3$는, $Na^{+}$ 이온만 주입된 $Al_2$O$_3$와 $^{137}$Cs 감마선 만 조사된 $Al_2$O$_3$보다 각각 defect traps에 구속된 전하운반체의 밀도와 defect traps의 밀도가 증강되었기 때문에, $Na^{+}$ 이온 주입 후 $^{137}$Cs 감마선 조사된 $Al_2$O$_3$보다 각각 20배, 5배 증가되었다. 주입 이온 선량과 에너지의 증가는 defect trap 밀도의 증가를 초래함으로, 이온 주입된 시료의 열자극 발광 세기는 이온의 선량과 에너지에 의존함을 알았다. 입사 이온의 질량이 증가함에 따라 열자극 발광 세기는 기하급수적으로 급격히 감소하였고, 이것은 열자극 발광 세기가 결함 생성률 뿐만 아니라, 이온의 주입 깊이에도 밀접한 관계가 있음을 보여주었다.

• Journal of Periodontal and Implant Science
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• 제42권4호
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• pp.119-126
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• 2012

Purpose: The aim of this study was to determine whether biphasic calcium phosphate (BCP) bone substitute with two different concentrations of Escherichia coli-expressed recombinant human bone morphogenetic protein 2 (ErhBMP-2) enhances new bone formation in a standardized rabbit sinus model and to evaluate the concentration-dependent effect of ErhBMP-2. Methods: Standardized, 6-mm diameter defects were made bilaterally on the maxillary sinus of 20 male New Zealand white rabbits. Following removal of the circular bony windows and reflection of the sinus membrane, BCP bone substitute without coating (control group) was applied into one defect and BCP bone substitute coated with ErhBMP-2 (experimental group) was applied into the other defect for each rabbit. The experimental group was divided into 2 subgroups according to the concentration of ErhBMP-2 (0.05 and 0.5 mg/mL). The animals were allowed to heal for either 4 or 8 weeks and sections of the augmented sinus and surrounding bone were analyzed by microcomputed tomography and histologically. Results: Histologic analysis revealed signs of new bone formation in both the control and experimental groups with a statistically significant increase in bone formation in experimental group 1 (0.05 mg/mL ErhBMP-2 coating) after a 4-week healing period. However, no statistically significant difference was found between experimental group 1 and experimental group 2 (0.5 mg/mL ErhBMP-2 coating) in osteoinductive potential (P<0.05). Conclusions: ErhBMP-2 administered using a BCP matrix significantly enhanced osteoinductive potential in a standardized rabbit sinus model. A concentration-dependent response was not found in the present study.

• 한국축산식품학회지
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• 제38권2호
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• pp.417-430
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• 2018

This study was conducted to determine the effects of NaCl concentration and cooking temperature on the color and pigment characteristics of presalted ground chicken breasts. Four treatments with different salt concentrations (0%, 1%, 2%, and 3%) were prepared and stored for 7 d prior to cooking. Each sample was cooked to four endpoint temperatures ($70^{\circ}C$, $75^{\circ}C$, $80^{\circ}C$, and $85^{\circ}C$). The salt concentration affected the color and pigment properties of the cooked ground chicken breasts. As the salt concentration increased, the cooking yield and residual nitrite content also increased. However, the samples with 1%, 2%, and 3% NaCl showed similar nitrosyl hemochrome and total pigment contents. Among the products containing salt, the samples with 3% NaCl showed the lowest percentage myoglobin denaturation (PMD) and the lowest CIE $a^*$ values. The cooking temperature had limited effects on the pigment properties of cooked ground chicken breasts. The oxidation-reduction potential and residual nitrite contents increased with cooking temperature, while the PMD, nitrosyl hemochrome, total pigment contents and CIE $a^*$ values were similar in the samples cooked at different temperatures. These results indicated that the addition of up to 2% salt to ground chicken breasts and storage for 7 d could cause the pink color defect of cooked products. However, the addition of 3% NaCl could reduce the redness of the cooked products.

• 대한기계학회논문집B
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• 제20권3호
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• pp.988-1004
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• 1996

The characteristics of flow and oxygen concentration are numerically studied in Czochralski 8" silicon crystal growing process considering radiative heat transfer. The analysis of net radiative heat flux on all relevant surfaces shows growing crystal affects the heater power. Furthermore, the variation of the radiative heat flux along the crystal surface in the growing direction is confirmed and should be a cause of thermal stress and defect of the crystal. The calculated distributions of temperature and, heat flux along the wall boundaries including melt/crystal interface, free surface and crucible wall indicate that the frequently used assumption of the thermal boundary conditions of insulated crucible bottom and constant temperature at crucible side wall is not suitable to meet the real physical boundary conditions. It is necessary, therefore, to calculate radiative heat transfer simultaneously with the melt flow in order to simulate the real CZ crystal growth. If only natural convection is considered, the oxygen concentration on the melt/crystal interface decreases and becomes uniform by the application of a cusp magnetic filed. The heater power needed also increases with increasing the magnetic field. For the case of counter rotation of the crystal and crucible, the magnetic field suppresses azimutal flow produced by the crucible rotation, which results in the higher oxygen concentration near the interface.

• Journal of Microbiology and Biotechnology
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• 제9권4호
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• pp.414-421
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• 1999

Helicobacter pylori were found to be resistant to azide but sensitive to vanadate, suggesting that defect in the P-type ATPase activity rather than F-type ATPase would be lethal to cell survival or growth. To elucidate the relationship between this enzyme inhibition and H. pylori death, we determined the effect of omeprazole (OMP) plus vanadate on enzyme activity and cell growth. The minimum inhibitory concentration (MIC; ca. 0.8$\mu$mol/disk) of vanadate for H. pylori growth was lowered over l0-fold with the aid of OMP, whereby its inhibitory potential toward the P-type ATPase activity was diametrically increased. Alternatively, we found that this enzyme activity was essential for active transport in H. pylori. From these observations, we strongly suggest that the immediate cause of the growth inhibition of H. pylori cells with OMP and/or vanadate might be defective in the cell's active transport due to the lack of P-type ATPase activity. From the spectral data with circular dichroism (CD) spectroscopy, we found that activated OMP (OAS) at concentration below MIC did not disrupt helical structures of membrane proteins. Separately, we determined the cytopathic effect of OAS by SDS-PAGE, indicating the change in the production of cytoplasmic protein but not cell membrane.

• 한국압력기기공학회 논문집
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• 제10권1호
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• pp.113-121
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• 2014

In this work, an integrated model including molecular dynamics and chemical rate theory was implemented to calculate the growth of point defect clusters(PDC) and copper-rich precipitates(CRP) which could change the mechanical properties of reactor pressure vessel(RPV) steels in a nuclear power plant. A number of time-dependent differential equations were established and numerically integrated to estimate the evolution of irradiation defects. The calculation showed that the concentration of the vacancies was higher than that of the self-interstitial atoms. The higher concentration of vacancies induced a formation of the CRPs in the later stage. The size of the CRPs was used to estimate the mechanical property changes in RPV steels, as is the same case with the PDCs. The calculation results were compared with the measured values of yield strength change and Charpy V-notch transition temperature shift, which were obtained from the surveillance test data of Korean light water reactors(LWRs). The estimated values were in fair agreement with the experimental results in spite of the uncertainty of the modeling parameters.

• 한국응용과학기술학회지
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• 제19권3호
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• pp.174-180
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• 2002

In recent days, the study of a new phosphorescent phosphor has been performed in order to overcome the defect of sulfide phosphor and increase the brightness and long after-glow characteristic of phosphorescent phosphor. Particularly, sulfide phosphor usually used is so chemically unstable that the study of oxide phosphors are processing. $Eu^{2+}$, $Nd^{3+}$ doped Ba-Al-O phosphors sintered at $600{\sim}1500^{\circ}C$ for 2hours had the PL emission spectrum and after-glow over $1200^{\circ}C$. In this system, as the mole concentration of alumina increases, emission bands of phosphors moved from 500nm to 380nm. The optimum concentration of flux was 5wt% and after-glow characteristics of phosphors were found at the host material molar ratio ($BaCO_{3}:Al_{2}O_{3}$), 1:1 and 1:3.