• 한국결정성장학회지
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• 제30권6호
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• pp.251-257
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• 2020

디스플레이용 유리를 통해 문자나 이미지를 뚜렷하고 빠르게 인식하기 위해서는 유리의 눈부심 현상(glare)을 억제해야 한다. 본 연구 연구에서는 에칭공정을 통해 유리 표면 형상 및 광학 특성 변화를 분석하여 눈부심 현상을 낮추고자 하였다. 에칭 공정은 에칭 용액인 BOE 및 HF의 농도를 변수로 수행하였다. 에칭과정에서 유리 표면에 F 이온이 포함된 화합물이 생성되어 돌기(projection) 형태로 불규칙한 패턴을 형성되었고, 이로 인해 유리의 광학적 특성이 변화되었다; 반사율은 2.5~4.6 %, 탁도는 4.5~6.6 %, 투과율은 77~9 2 %, 그리고 광택도는 82~107 GU 범위. 그 결과 유리의 눈부심 현상을 억제하면서도 다른 광학적 특성의 손실을 최소화하는 에칭 조건을 확보하였다.

• 영미문화
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• 제16권2호
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• pp.47-70
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• 2016

Under the inhumane oppression of imperialism, the Third World's political violence has been often represented as an immediate and explosive one with an instant, concentrated visibility. Yet the ecological and psychological exploitation of the Third-World countries by empires, as Rob Nixon insists, shows the relative invisibility of slow violence. This paper is to reveal this slow violence of the marginalized areas symbolized as the lowland. Although Arne Naess' deep ecology promotes the inherent worth of living beings regardless of their instrumental utility to human needs. this paper deals with three postcolonial ecological textbooks which criticize the white-centered deep ecology: Amitav Ghosh's The Glass Palace, Jhumpa Lahiri's The Lowland, and Barbara Kingsolver's The Poisonwood Bible. Through postcolonial critical study, this paper finds out that all these three works have some themes in common. First, these postcolonial works assume a shape of family saga which is parallel to the slow violence of ecological and psychological plundering of empires in the postcolonial countries. Second, like the mangroves which have a tenacious hold on life, these postcolonial people rather overcome the heterogenic challenge with the sturdy and tough mind than defeated. Third, the native people's ethics of earth functions as the stronghold for their respectable lifestyle in their indigenous historicity. Finally, as a big fat brother, the Americanized globalization or neoliberalism is warned as the neocolonialism which is often shown as the disguised pattern of greenwashing. Namely, the people's self-enhancement is always prior to the imperialistic development or neoliberalism in the postcolonial ecological texts which sharply contrast the native's life consciousness and the empire's development theory.

• 한국표면공학회지
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• 제54권3호
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• pp.144-151
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• 2021

In the present work, planar-type ZnO powder of [0001] plane with a high aspect ratio range of 20:1 to 50:1 was synthesized. Ag or CuO could be coated on the planar-type ZnO powder by wet methods such as centrifugation or ball milling. During the coating, the average size of the powder was slightly increased while maintaining the shape and XRD pattern of ZnO. When Ag or CuO was coated, the absolute value of the zeta potential, as well as the concentration of oxygen vacancy, was increased. Ag or CuO coated planar-type ZnO power exhibited excellent antibacterial performance, which seems to be related to their high electrostatic attraction force. They could be made into a masterbatch by mixing with ABS resin, and their applicability to antibacterial substances was confirmed by manufacturing the caps of a keyboard.

• Journal of Periodontal and Implant Science
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• 제51권1호
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• pp.40-52
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• 2021

Purpose: Various crosslinking methods have been introduced to increase the longevity of collagen membranes. The aim of this study was to compare and evaluate the degradation and bone regeneration patterns of 3 collagen membranes. Methods: Four 8-mm-diameter circular bone defects were created in the calvaria of 10 rabbits. In each rabbit, each defect was randomly allocated to 1) the sham control group, 2) the non-crosslinked collagen sponge (NS) group, 3) the chemically crosslinked collagen membrane (CCM) group, or 4) the biphasic calcium phosphate (BCP)-supplemented ultraviolet (UV)-crosslinked collagen membrane (UVM) group. Each defect was covered with the allocated membrane without any graft material. Rabbits were sacrificed at either 2 or 8 weeks post-surgery, and radiographic and histologic analyses were done. Results: New bone formed underneath the membrane in defects in the CCM and UVM groups, with a distinctive new bone formation pattern, while new bone formed from the base of the defect in the NS and control groups. The CCM maintained its shape until 8 weeks, while the UVM and NS were fully degraded at 8 weeks; simultaneously, sustained inflammatory infiltration was found in the margin of the CCM, while it was absent in the UVM. In conclusion, the CCM showed longer longevity than the UVM, but was accompanied by higher levels of inflammation. Conclusions: Both the CCM and UVM showed distinctive patterns of enhancement in new bone formation in the early phase. UV crosslinking can be a biocompatible alternative to chemical crosslinking.

• 한국수자원학회논문집
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• 제55권1호
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• pp.59-70
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• 2022

상수도관망은 대표적인 사회기반시설로 수원에서 수용가에게 물을 공급하는 과정에서 병원성 미생물을 소독하기 위해 염소를 주입한다. 안전한 물의 공급을 위해 잔류염소 농도 기준(0.1-4.0 mg/L)을 유지하도록 규정하고 있으나, 사용자의 사용 패턴, 수령, 상수도관망의 형식 및 특징은 수리학적(i.e., 절점의 압력, 관로의 유속) 및 수질적(i.e., 잔류염소 농도) 특징에 영향을 미친다. 따라서, 본 연구에서는 Multi-objective Harmony Search (MOHS)를 사용하여 수질-수리 인자를 고려한 상수도관망 최적 설계 기법을 개발하였다. 설계인자로는 설계비용과 시스템 탄력성을 고려하였으며, 절점의 압력과 잔류염소 농도를 제약조건으로 적용하였다. 도출된 최적설계안은 상수도관망의 형식 및 특징에 따라 분석하였다. 이러한 최적설계안은 경제적인 측면과 수질 측면의 안전성을 충족할 수 있으며, 사용자의 사용성을 증가시킬 수 있다.

• 한국정보통신학회논문지
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• 제26권6호
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• pp.859-864
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• 2022

매년 교통사고의 가장 큰 원인으로 손꼽히는 졸음운전은 운전자의 수면 부족, 산소 부족, 긴장감의 저하, 신체의 피로 등과 같은 다양한 요인을 동반한다. 졸음 유무를 확인하는 일반적인 방법으로 운전자의 표정과 주행패턴을 파악하는 방법, 심전도, 산소포화도, 뇌파와 같은 생체신호를 분석하는 방법들이 연구되고 있다. 본 논문은 영상을 검출하는 딥러닝 모델과 생체 신호 측정 기술을 이용한 운전자 피로 감지 시스템을 제안한다. 제안 방법은 일차적으로 딥러닝을 이용하여 운전자의 눈 모양과 하품 유무, 졸음으로 예상되는 신체 동작을 파악하여 졸음 상태를 감지한다. 이차적으로 맥파 신호와 체온을 이용하여 운전자의 피로 상태를 파악하여 시스템의 정확도를 높이도록 설계하였다. 실험 결과, 실시간 영상에서 운전자의 졸음 유무 판별이 안정적으로 가능하였으며 각성상태와 졸음 상태에서의 분당 심박수와 체온을 비교하여 본 연구의 타당성을 확인할 수 있었다.

• 천문학회지
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• 제54권2호
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• pp.61-70
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• 2021

We investigate 20 post-coronal mass ejection (CME) blobs formed in the post-CME current sheet (CS) that were observed by K-Cor on 2017 September 10. By visual inspection of the trajectories and projected speed variations of each blob, we find that all blobs except one show irregular "zigzag" trajectories resembling transverse oscillatory motions along the CS, and have at least one oscillatory pattern in their instantaneous radial speeds. Their oscillation periods are ranging from 30 to 91 s and their speed amplitudes from 128 to 902 km s-1. Among 19 blobs, 10 blobs have experienced at least two cycles of radial speed oscillations with different speed amplitudes and periods, while 9 blobs undergo one oscillation cycle. To examine whether or not the apparent speed oscillations can be explained by vortex shedding, we estimate the quantitative parameter of vortex shedding, the Strouhal number, by using the observed lateral widths, linear speeds, and oscillation periods of the blobs. We then compare our estimates with theoretical and experimental results from MHD simulations and fluid dynamic experiments. We find that the observed Strouhal numbers range from 0.2 to 2.1, consistent with those (0.15-3.0) from fluid dynamic experiments of bluff spheres, while they are higher than those (0.15-0.25) from MHD simulations of cylindrical shapes. We thus find that blobs formed in a post-CME CS undergo kinematic oscillations caused by fluid dynamic vortex shedding. The vortex shedding is driven by the interaction of the outward-moving blob having a bluff spherical shape with the background plasma in the post-CME CS.

• 한국재난정보학회 논문집
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• 제17권4호
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• pp.839-847
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• 2021

연구목적: 본 연구에서는 휨을 받는 탄소 나노튜브 보강 기능경사복합재 판의 구조적 거동을 해석하였다. 이를 위해, 등기하해석과 고차전단변형이론을 결합한 수치해석 방법을 이용하였다. 연구방법: 전단보정계수를 사용하지 않고 기하학적 비선형성을 고려할 수 있는 고차전단변형이론을 통하여 휨이 작용하는 탄소 나노튜브 보강 기능경사복합재 판의 비선형 거동방정식을 유도하였으며, 수정된 Newton-Raphson 반복 기법을 사용하여 등기하해석방법에 기반한 시스템 방정식의 해를 구하였다. 연구결과: 탄소 나노튜브의 배치 양상, 폭-두께 비 및 경계조건은 휨을 받는 탄소 나노튜브 보강 기능경사복합재 판의 구조적 거동에 많은 영향을 끼침을 확인하였다. 결론: 제안된 고차전단변형이론에 근거한 등기하해석 방법은 휨을 받는 탄소 나노튜브 보강 기능경사복합재 판의 구조적 거동을 정확하고 효과적으로 해석하는 것을 알 수 있었다.

• 대한한의학원전학회지
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• 제35권3호
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• pp.41-58
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• 2022

Objectives : In this paper, the outline and overall content of the Majinhwiseong, a specialized medical text on measles written by Lee Wonpung was introduced, along with its academic historical meaning. Methods : The entire Majinhwiseong was analyzed according to content and form. In terms of form, organization, construction, cited literature, etc., were studied, while in terms of content, diagnosis of disease pattern and treatment formulas were studied. Later, based on cited medical texts and the author's social position, the academic historical meaning of this book was discussed. Results : Through the Majinhwiseong, Lee Wonpung strengthened the credibility of the text by not only providing medical knowledge on measles but listing their sources and comparing and analyzing related contents. In the diagnosis part, Lee focused on the changes in symptom, shape, color, and pulse of measles, discussing in detail its differential diagnostic methods. In the treatment part, while listing numerous formulas suggested by Ming (明) masters, Lee did not leave out treatment experiences of Joseon physicians. Meanwhile, the Majinhwiseong is indicative of measles medicine in 18th century Joseon having been progressed in the private sector rather than the official, and how the results of private sector medicine were being absorbed into the official realm through the Uiyakdongcham (議藥同參) system. Conclusions : The Majinhwiseong is a practical treatment manual written by clinician Lee Wonpung to deal measles which was widely spread at the time. The author organized existing medical knowledge on measles for clinicians while reflecting outcomes and medical situation of Joseon physicians in this book. Based on these findings, we could verify that medicine in 18th century Joseon had been progressing actively around the private medical sector.

• 한국작물학회지
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• 제36권3호
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• pp.241-248
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• 1991

한국 재래품종, 잡초형 벼인 샤례벼와 앵미 그리고 불복장미 등의 입형 종피색ㆍamy1ose 함량ㆍAlkali 붕양도 및 esterase 반응성 등 몇가지 벼 형질들을 검토하여 Indica의 범주에 속하는 것들이 있음을 밝히고 고농서와 근래 일본인들이 우리나라에서 채집 분류 보고한 기록들 중 Indica에 관한 것을 검토하였다. 이것을 요약하면 다음과 같다. 1. 1920년대에 수집 보존되어 오는 한국 재래품종 중 분명히 Indica의 범주에 속하는 것들이 있다 2. 샤례벼 집단에서 분리 계통화한 것들 중에도 Indica 범주에 속하는 것들이 있다 3. 농가 포장에서 수집한 앵미 중에도Indica 범주에 속하는 것들이 있다. 4. 1302년 불복장미로 발견된 한 시료는 쌀의 형태와 amylose 함량으로 보아 당시 Japonica와 Indica가 혼재되었던 것으로 생각된다. 5. 과거의 기록과 보고를 검토하여 우리나라에는 Japonica 뿐만 아니라 Indica도 오래전부터 재배되었을 것으로 추론하였다.