• Corrosion Science and Technology
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• 제14권3호
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• pp.120-126
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• 2015

The usage of bending products recently have increased since many industries such as automobile, aerospace, shipbuilding, and chemical plants need the application of pipings. Bending process is one of the inevitable steps to fabricate the facilities. Induction heat bending is composed of compressive bending process by local heating and cooling. This work focused on the effect of induction heat bending process on the properties of ASME SA312 Gr. TP304 stainless steel pipes. Tests were performed for base metal and bended area including extrados, intrados, crown up, and down parts. Microstructure was analyzed using an optical microscope and SEM. In order to determine intergranular corrosion resistance, Double Loop Electrochemical Potentiokinetic Reactivation (DL-EPR) test and ASTM A262 practice A and C tests were done. Every specimen revealed non-metallic inclusion free under the criteria of 1.5i of the standard and the induction heat bending process did not affect the non-metallic inclusion in the alloys. Also, all the bended specimens had finer grain size than ASTM grain size number 5 corresponding to the grain sizes of the base metal and thus the grain size of the pipe bended by induction heat bending process is acceptable. Hardness of transition start, bend, and transition end areas of ASME SA312 TP304 stainless steel was a little higher than that of base metal. Intergranular corrosion behavior was determined by ASTM A262 practice A and C and DL-EPR test, and respectively step structure, corrosion rate under 0.3 mm/y, and Degree of Sensitization (DOS) of 0.001~0.075% were obtained. That is, the induction heat bending process didn't affect the intergranular corrosion behavior of ASME SA312 TP304 stainless steel.

• Nuclear Engineering and Technology
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• 제52권9호
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• pp.1881-1895
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• 2020

The theoretical aspects behind the reactor depletion capability of the Monte Carlo code MCS developed at the Ulsan National Institute of Science and Technology (UNIST) and practical results of this depletion feature for a Material-Testing Reactor (MTR) with plate-type fuel are described in this paper. A verification of MCS results is first performed against MCNP6 to confirm the suitability of MCS for the criticality and depletion analysis of the MTR. Then, the dependence of the effective neutron multiplication factor to the number of axial and radial depletion cells adopted in the fuel plates is performed with MCS in order to determine the minimum spatial segmentation of the fuel plates. Monte Carlo depletion results with 37,800 depletion cells are provided by MCS within acceptable calculation time and memory usage. The results show that at least 7 axial meshes per fuel plate are required to reach the same precision as the reference calculation whereas no significant differences are observed when modeling 1 or 10 radial meshes per fuel plate. This study demonstrates that MCS can address the need for Monte Carlo codes capable of providing reference solutions to complex reactor depletion problems with refined meshes for fuel management and research reactor applications.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.217-217
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• 2016

The amorphous InGaZnO (a-IGZO) is widely accepted as a promising channel material for thin-film transistor (TFT) applications owing to their outstanding electrical properties [1, 2]. However, a-IGZO TFTs have still suffered from their bias instability with illumination [1-4]. Up to now, many researchers have studied the sub-gap density of states (DOS) as the root cause of instability. It is well known that defect states can influence on the performances and stabilities of a-IGZO TFTs. The defects states should be closely related with the deposition condition, including sputtering power, and pressure. Nevertheless, it has not been reported how these defects are created during conventional RF magnetron sputtering. In general, during conventional RF magnetron sputtering process, negative oxygen ions (NOIs) can be generated by electron attachment in oxygen atom near target surface and then accelerated up to few hundreds eV by a self-bias; at this time, the high energy bombardment of NOIs induce defects in oxide thin films. Recently, we have reported that the properties of IGZO thin films are strongly related with effects of NOIs which are generated during the sputtering process [5]. From our previous results, the electrical characteristics and the chemical bonding states of a-IGZO thin films were depended with the bombardment energy of NOIs. And also, we suggest that the deep sub-gap states in a-IGZO as well as thin film properties would be influenced by the bombardment of high energetic NOIs during the sputtering process.In this study, we will introduce our novel technology named as Magnetic Field Shielded Sputtering (MFSS) process to prevent the NOIs bombardment effects and present how much to be improved the properties of a-IGZO thin film by this new deposition method. We deposited a-IGZO thin films by MFSS on SiO2/p-Si and glass substrate at various process conditions, after which we investigated the morphology, optical and electrical properties of the a-IGZO thin films.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.160-160
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• 2015

InGaZnO (IGZO) thin-film transistors (TFTs) are very promising due to their potential use in high performance display backplane [1]. However, the stability of IGZO TFTs under the various stresses has been issued for the practical IGZO applications [2]. Up to now, many researchers have studied to understand the sub-gap density of states (DOS) as the root cause of instability [3]. Nomura et al. reported that these deep defects are located in the surface layer of the IGZO channel [4]. Also, Kim et al. reported that the interfacial traps can be affected by different RF-power during RF magnetron sputtering process [5]. It is well known that these trap states can influence on the performances and stabilities of IGZO TFTs. Nevertheless, it has not been reported how these defect states are created during conventional RF magnetron sputtering. In general, during conventional RF magnetron sputtering process, negative oxygen ions (NOI) can be generated by electron attachment in oxygen atom near target surface and accelerated up to few hundreds eV by self-bias of RF magnetron sputter; the high energy bombardment of NOIs generates bulk defects in oxide thin films [6-10] and can change the defect states of IGZO thin film. In this study, we have confirmed that the NOIs accelerated by the self-bias were one of the dominant causes of instability in IGZO TFTs when the channel layer was deposited by conventional RF magnetron sputtering system. Finally, we will introduce our novel technology named as Magnetic Field Shielded Sputtering (MFSS) process [9-10] to eliminate the NOI bombardment effects and present how much to be improved the instability of IGZO TFTs by this new deposition method.

• Imaging Science in Dentistry
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• 제43권3호
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• pp.145-151
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• 2013

Purpose: This study was performed to evaluate and compare the radiopacity of dentin, enamel, and 8 restorative composites on conventional radiograph and digital images with different resolutions. Materials and Methods: Specimens were fabricated from 8 materials and human molars were longitudinally sectioned 1.0 mm thick to include both enamel and dentin. The specimens and tooth sections were imaged by conventional radiograph using #4 sized intraoral film and digital images were taken in high speed and high resolution modes using a phosphor storage plate. Densitometric evaluation of the enamel, dentin, restorative materials, a lead sheet, and an aluminum step wedge was performed on the radiographic images. For the evaluation, the Al equivalent (mm) for each material was calculated. The data were analyzed using one-way ANOVA and Tukey's test (p<0.05), considering the material factor and then the radiographic method factor, individually. Results: The high speed mode allowed the highest radiopacity, while the high resolution mode generated the lowest values. Furthermore, the high resolution mode was the most efficient method for radiographic differentiation between restorative composites and dentin. The conventional radiograph was the most effective in enabling differentiation between enamel and composites. The high speed mode was the least effective in enabling radiographic differentiation between the dental tissues and restorative composites. Conclusion: The high speed mode of digital imaging was not effective for differentiation between enamel and composites. This made it less effective than the high resolution mode and conventional radiographs. All of the composites evaluated showed radiopacity values that fit the ISO 4049 recommendations.

• Journal of Radiation Protection and Research
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• 제16권1호
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• pp.43-52
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• 1991

DOSE, LIMCAL 그리고 PABLM을 포함한 방사선피폭선량프로그램에 대하여 비교 연구가 행하여졌다. DOSE 프로그램은 국내 중 저준위 방사선폐기물 처분 예비안전성평가를 위해 확립되었으며, 나머지 두 프로그램은 안전성 평가에 적용한 바 있는 프로그램들이다. 연구 결과는 C-14과 Pu-239를 제외하고 1승(mrem/yr)범위에서 잘 일치하고 있다. PABLM은 DOSE와 LIMCAL과 비교할 때 Pu-239의 경우에서 작게 나타나고 있는 반면에 C-l4의 경우에는 크게 나타나고 있다. C-14의 편차는 소개된 이동모델에서의 차이 때문이며 Pu-239의 차이는 두 프로그램과 다른 선량전환인자 값을 적용함으로써 발생한 것임을 알 수 있다.

• Tuberculosis and Respiratory Diseases
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• 제80권1호
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• pp.69-76
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• 2017

Background: Much of the attention of tuberculosis (TB) programs is focused on outcomes of microbiological cure and mortality, and health related quality of life (HRQL) is undervalued. Also, TB patients have a significantly higher risk of developing depression and anxiety compared with those in the general population. We intend to evaluate the HRQL and the prevalence of symptoms of depression and anxiety in hospitalized patients with TB. Methods: Cross-sectional study in a tertiary care hospital in Brazil. Adult patients with pulmonary TB that were hospitalized during the study period were identified and invited to participate. HRQL was measured using the Medical Outcomes Study Short Form-36 (SF-36) version 2. Hospital Anxiety and Depression Scale (HADS) was used to record symptoms of anxiety and depression. Results: Eighty-six patients were included in the analysis. The mean age of all patients was $44.6{\pm}15.4$ years, 69.8% were male, and 53.5% were white. Thirty-two patients (37.2%) were human immunodeficiency virus positive. Twenty-seven patients (31.4%) met study criteria for depression (HADS depression score ${\geq}11$) and 33 (38.4%) had anxiety (HADS anxiety score ${\geq}11$). Scores on all domains of SF-36 were significantly lower than the Brazilian norm scores (p<0.001). Conclusion: The present study shows that TB patients may have a poor HRQL. Additionally, we found a possible high prevalence of depression and anxiety in this population. Health care workers should be aware of these psychological disorders to enable a better management of these patients. The treatment of these comorbidities may be associated with better TB outcomes.

• Asian-Australasian Journal of Animal Sciences
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• 제26권11호
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• pp.1630-1636
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• 2013

An investigation was carried out to assess the carcass characteristics and meat quality aspects of immunocastrated male pigs of medium genetic potential for lean meat deposition in carcass (53 to 55%). When the crossbred Large White x Landrace pigs (n = 45) were 70 days old, they were distributed in a totally randomized design in three treatments (castrated males, females and immunocastrated males) with three replicates of five animals. The pigs were slaughtered when they were 140 days old. Carcass temperature and pH were recorded twice, at 45 min and 24 h after slaughter. The carcasses were evaluated for hot and cold carcass yield, commercial cuts yield, length and depth, back fat thickness, loin eye area and lean meat percentage. The Longissimus dorsi muscle was extracted for analysis of color ($L^*$, $a^*$, $b^*$), exudate loss, cooking loss and centesimal and sensorial analysis of the meat. There were no significant differences for the evaluated parameters between castrated males, immunocastrated males and females, except for backfat thickness between the 7th and 8th thoracic vertebra and the point P2 (lower for immunocastrated males) and carcass temperature at 45 min post slaughter (higher in immunocastrated males), however, this did not interfer with the rate of pH decrease post mortem and the meat quality. The results from this research did not indicate a benefit of immunocastration on carcass characteristics of pigs of medium genetic potential for lean meat deposition in carcass, when compared to surgical castration.

• 대한기계학회논문집
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• 제15권6호
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• pp.2026-2036
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• 1991

본 연구에서는 동력전달용 치차설계 전문가 시스템을 구축하기 위한 일단의 연구로서 먼저, 치차의 시험중 또는 사용중에 일어나는 파손에 대하여 파손의 원인탐 색과 대책수립을 위한 전문가 시스템을 개발한다.

• 한국환경농학회지
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• 제19권4호
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• pp.324-327
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• 2000

저선량 조사한 대두종자의 초기생육과 대두 유식물체의 후속고선량에 대한 방사선 감수성 변화를 알아보고자 저선량 0, 4, 8, 12, 20 Gy를 조사하여 재배한 대두 유식물체에 ${\gamma}$선 50, 100, 200 Gy를 조사한 후 생육상황을 관찰하였다. 저선량 조사에 의해 대두 신규종자의 발아율 증가효과는 없었으나 작물 생장 증대효과는 있었으며 저선량 8 Gy 조사구가 가장 효과적이었다. 대두유식물체의 고선량 방사선에 의한 생육장해는 사전 저선량조사에 의해 크게 감소되었으며 저선량 조사에 의한 고선량 방사선 저항성 증가는 8 Gy와 20 Gy조사에서 가장 효과적이었다.