• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제40회 동계학술대회 초록집
• /
• pp.48-48
• /
• 2011

We have developed a chemically-driven top-down approach using vapor phase HCl to form various GaN nanostructures and successfully demonstrated dislocation-free and strain-relaxed GaN nanostructures without etching damage formed by a selective dissociation method. Our approach overcomes many limitations encountered in previous approaches. There is no need to make a pattern, complicated process, and expensive equipment, but it produces a high-quality nanostructure over a large area at low cost. As far as we know, this is the first time that various types of high-quality GaN nanostructures, such as dot, cone, and rod, could be formed by a chemical method without the use of a mask or pattern, especially on the Ga-polar GaN. It is well known that the Ga-polar GaN is difficult to etch by the common chemical wet etching method because of the chemical stability of GaN. Our chemically driven GaN nanostructures show excellent structure and optical properties. The formed nanostructure had various facets depending on the etching conditions and showed a high crystal quality due to the removal of defects, such as dislocations. These structure properties derived excellent optical performance of the GaN nanostructure. The GaN nanostructure had increased internal and external quantum efficiency due to increased light extraction, reduced strain, and improved crystal quality. The chemically driven GaN nanostructure shows promise in applications such as efficient light-emitting diodes, field emitters, and sensors.

• Journal of Electrical Engineering and information Science
• /
• 제2권5호
• /
• pp.65-71
• /
• 1997

We present heterojunction solar cells with a structure of metal/a-Si:H(n-i-p)/poly-Si(n-p)/metal for the terrestrial applications. This cell consists fo two component cells: a top n-i-p junction a-Si:Hi cell with wide-bandgap 1.8eV and a bottom n-p junction poly-Si cell with narrow-bandgap 1.1eV. The efficiency influencing factors of the solar cell were investigated in terms of simulation an experiment. Three main topics of the investigated study were the bottom cell with n-p junction poly-Si, the top a-Si:H cell with n-i-p junction, and the interface layer effects of heterojunction cell. The efficiency of bottom cell was improved with a pretreatment temperature of 900$^{\circ}C$, surface polishing, emitter thickness of 0.43$\mu\textrm{m}$, top Yb metal, and grid finger shading of 7% coverage. The process optimized cell showed a conversion efficiency about 16%. Top cell was grown by suing a photo-CVD system which gave an ion damage free and good p/i-a-Si:H layer interface. The heterojunction interface effect was examined with three different surface states; a chemical passivation, thermal oxide passivation, and Yb metal. the oxide passivated cell exhibited the higher photocurrent generation and better spectral response.

• 한국의사학회지
• /
• 제30권1호
• /
• pp.33-41
• /
• 2017

This study utilized Corpus-based Analysis process to compare the Cold Pathogen chapter in the 'English version of "Donguibogam"' to the 'English version of the "Shanghanlun"' translated by 罗希文 (Luo xi wen). Results of the linguistic analysis indicate that TTR, a ratio of number of types to number of tokens in the English version of "Shanghanlun" was 5.92% while TTR in the Cold pathogen chapter of English version of "Donguibogam" was 6.01%. It was also noted that the types of words frequently appearing in the two publications were the scientific name of medicinal herbs; the method of producing the herbal prescription (including terminology representing weights and measures); and Chinese descriptions of concepts considered important in both Korean and Chinese medicinal practices. Finally, it was possible to find points of comparison in naming of symptoms, diagnosis, prescriptions, and respective names of six meridians. Though the language difference is minimal, the vocabulary found in the Cold Pathogen chapter of "Donguibogam" was more diverse than Luo's translation of "Sanghanlun". In general, literal translation in keeping with the sense of original text was better performed in Luo's translation of the "Sanghanlun" whereas the English version of the Cold Pathogen chapter in the "Donguibogam" was more of a "free" translation.

• Archives of Plastic Surgery
• /
• 제37권4호
• /
• pp.496-498
• /
• 2010

Purpose: Lacerations requiring formal wound closure compose a significant number of all childhood injuries presenting to the emergency department. The problem with conventional suture technique are that suture removal is quite cumbersome, especially in children. Unwanted soft tissue damage can result in the process of suture removal, which calls for sedation, stressful for both medical personnel and child. The purpose of this study is to introduce the convenient suture technique for pediatric facial lacerations. Methods: Children under the age of four, presenting to the emergency department with facial lacerations were enrolled in the study. From March 2008 to June 2009, 63 patients (41 males and 22 females) with an average age of 1.4 years were treated with our convenient suture technique using utilized a loop suspended above a double, flat tie. Clean, tension free wounds were treated with our technique, wounds with significant skin defect and concomitant fractures were excluded. Results: The Patients were followed-up in 1, 3 and 5 days postoperatively. On the third hospital visit, suture removal was done by simply cutting the loop suspended above the wound margin and gently pulling the thread with forceps. There were no significant differences in the rates of infection and dehiscence compared with conventional suture technique. Conclusion: The use of our technique was to be simple with similar operative time compared with conventional suture technique. Removal of suture materials were easy without unwanted injuries to the surrounding tissue which resulted in less discomfort for the patient and greater parental satisfaction, minimized the complications. It can be considered as a viable alternative in the repair of pediatric facial lacerations.

• 한국초전도ㆍ저온공학회논문지
• /
• 제24권3호
• /
• pp.47-51
• /
• 2022

With the innovative development of bio, pharmaceutical, and semiconductor technologies, it is essential to demand a next-generation transfer system that minimizes dust and vibrations generated during the manufacturing process. In order to develop dust-free and non-contact transfer systems, the high temperature superconductor (HTS) bulks have been applied as a magnet for levitation. However, sintered HTS bulk magnets are limited in their applications due to their relatively low critical current density (J_c) of several kA/cm² and low mechanical properties as a ceramic material. In addition, during cooling to cryogenic temperatures repeatedly, cracks and damage may occur by thermal shock. On the other hand, the bulk magnets made by stacked HTS tapes have various advantages, such as relatively high mechanical properties by alternate stacking of the metal and ceramic layer, high magnetic levitation performance by using coated conductors with high J_c of several MA/cm², consistent superconducting properties, miniaturization, light-weight, etc. In this study, we tried to fabricate HTS tapes stacked bulk magnets with 60 mm × 60 mm area and various numbers of HTS tape stacked layers for magnetic levitation. In order to examine the levitation forces of bulk magnets stacked with HTS tapes from 1 to 16 layers, specialized force measurement apparatus was made and adapted to measure the levitation force. By increasing the number of HTS tapes stacked layers, the levitation force of bulk magnet become larger. 16 HTS tapes stacked bulk magnets show promising levitation force of about 23.5 N, 6.538 kPa at 10 mm of levitated distance from NdFeB permanent magnet.

• FOCUS: LIFE SCIENCE
• /
• 제1호
• /
• pp.2.1-2.6
• /
• 2024

This article provides detailed instructions for the correct installation, maintenance, and troubleshooting of capillary gas chromatography (GC) columns. It emphasizes the importance of proper installation to ensure optimal performance and longevity of the column. The document covers various aspects such as column trimming, installation, conditioning, testing, storage, and ferrule selection. The installation process involves ensuring that the heated zones of the GC are cool before placing the column cage in the column oven. It is essential to avoid sharp bends or stress on the capillary column during installation and to connect the front end of the column into the GC inlet at the recommended insertion distance. The document also provides guidance on trimming the column, including the use of a ceramic wafer or capillary column cutter to achieve a clean, burr-free cut. For previously used columns, it recommends removing any capillary caps, positioning the nut and ferrule, and trimming 1-2 cm from the column. After installation, the column should be purged with carrier gas to remove any oxygen and avoid oxidizing the column. Conditioning the column involves ramping to the upper isothermal temperature limit and maintaining this temperature for a specified duration. It is crucial to maintain carrier gas flow during conditioning and not exceed the upper temperature limit of the column to avoid phase damage. The document also discusses testing column performance using a suitable method and performing a test injection to assess performance. It provides recommendations for column storage, including flame-sealing the capillary ends or using retention gaps for long-term storage. Additionally, it emphasizes the importance of routine maintenance and replacement of GC consumables to extend the column's lifetime. Ferrule selection is another important aspect covered in the article, with a variety of ferrule materials available for different applications. The characteristics of common ferrule options are presented in a table, including temperature limits, reusability, and suitability for specific detector types.

• 한국콘텐츠학회논문지
• /
• 제12권10호
• /
• pp.254-279
• /
• 2012

본 연구의 목적은 가정폭력 피해 이주 여성들의 대처과정에 관한 실체이론(Substantive theory)을 개발하여, 그들이 폭력에서 벗어나 자립할 있는 실천적 방안을 제시하는데 있다. 연구문제는 '가정폭력에 대한 결혼이주여성의 대처하는 과정은 어떠한가?' 이다. 본 연구는 근거이론 방법을 적용하였으며, 가정폭력을 경험한 11명의 결혼 이주여성들이 참여하였다. 패러다임 모형 분석 결과, 중심현상은 '심신의 황폐화'로 나타났고, 인과조건은 '고통의 수레바퀴', '속수무책 당하는 폭력'으로 나타났다. 또한 맥락적 조건은 '외로운 성장기', '부조리한 결혼', '냉담한 현실'로 나타났다. 중심현상 '심신의 황폐화'는 중재조건의 영향을 받으면서 작용/상호작용을 하는데, 이때 중재조건은 '사회적 도움', '문화차이', '무력감'이었으며, 작용/상호작용은 '순응하기', '저항하기', '자기보호', '자기강화' 등으로 나타났다. 연구결과, '현실유지하기', '결단하기', '새로운 삶 시작하기'가 도출되었다. 핵심범주로는 '심신의 황폐화를 딛고 다시 일어서기'를 상정하였다. 참여자들의 가정폭력 대처과정은 충격의 단계 ${\rightarrow}$ 인고의 단계 ${\rightarrow}$ 회한의 단계 ${\rightarrow}$ 재기의 단계이며, 참여자들의 대처유형은 "현실지탱형","회귀형","미래모색형" 등 세 가지로 구분되었다.

• 마이크로전자및패키징학회지
• /
• 제9권4호
• /
• pp.11-16
• /
• 2002

본 연구에서는 $SrBi_2Ta_2O_9$ (SBT)박막의 고속식각에 따른 잔류물질 및 식각 손상의 영향을 조사하였다. ICP-RIE (inductively coupled plasma reactive ion etching) 의 ICP power와 CCP(capacitively coupled plasma) power를 변화시키면서 고속식각에 따른 박막의 손상과 열화를 XPS 분석과 Capacitance-Voltage (C-V) 측정을 통하여 알아보았다. ICP와 CCP의 power가 증가함에 따라 식각율이 증가하였고 ICP power가 700 W, CCP power가 200 W 일때 식각율은 900$\AA$/min이었다. 강유전체의 건식식각에 있어서 문제점이 플라즈마에 의한 강유전체 박막의 열화인데 반응가스 $Ar/C1_2/CHF_3$를 20/14/2의 비율로 사용하고 ICP와 CCP power를 각각 700w와 200w로 사용하였을 때 전혀 열화되지 않는 강유전체 박막의 특성을 얻을 수 있었다. 본 연구 결과는 Metal-Ferroelectric-Semiconductor (MFS) 또는 Metal-Ferroelectric-Insulator-Semiconductor (MFIS) 구조를 가지는 단일 트랜지스터형 강유전체 메모리 소자를 만드는데 건식 식각이 응용될 수 있음을 보여준다

• 대한원격탐사학회지
• /
• 제38권6_3호
• /
• pp.1761-1775
• /
• 2022

예측하기 힘든 기후변화로 인해 물 관련 재해의 발생 빈도와 피해 규모도 지속적으로 증가하는 추세이다. 재난관리의 측면에서 광범위한 지역의 피해면적을 파악하고, 중·장기적 예측을 위한 모니터링이 필수적이다. 수재해 분야에서 광역적 모니터링을 위해 Synthetic Aperture Radar (SAR) 위성영상을 활용한 원격탐사 기술 연구가 활발히 진행되고 있다. 수재해 모니터링을 위한 시계열 분석에는 방대한 양의 영상수집과 잡음이 많은 레이더 산란 특성을 고려한 복잡한 전처리과정이 필요하며, 이를 위해 상당한 시간이 소요되는 한계가 있다. 최근 클라우드 컴퓨팅 기술의 발전과 함께 위성 빅데이터를 활용한 시·공간 분석이 가능한 많은 플랫폼들이 제안되고 있다. 구글어스엔진(Google Earth Engine, GEE)은 대표적인 플랫폼으로, 600여개의 위성 자료를 무료로 제공하고 있으며 위성영상의 분석준비데이터를 기반으로 준-실시간 시·공간 분석이 가능하다. 이에 본 연구에서는 구글어스엔진을 활용한 즉각적인 수재해 피해 탐지와 중·장기적 시계열 관측 연구를 수행하였다. 변화탐지에 주로 활용되는 Otsu 기법을 통해 '20년 발생한 집중호우를 중심으로 하천 범람으로 인한 하폭의 변화와 피해 면적을 확인하였다. 또한 재난관리 측면에서 모니터링의 중요성이 요구되는 만큼 상습침수지역으로 선정된 연구대상 지역을 중심으로 '18년부터 '22년까지의 시계열 수체의 변화 경향을 확인하였다. 구글어스엔진은 자바스크립트 기반 코딩을 통한 짧은 처리시간, 시공간 분석과 표출의 강점으로 수재해 분야 활용이 가능할 것으로 판단된다. 더불어 향후 다양한 위성 빅데이터와의 연계를 통해 활용 분야가 확대될 것으로 기대된다.

• Animal Bioscience
• /
• 제37권2호
• /
• pp.193-202
• /
• 2024

Objective: Oxidative stress (OS) is a pathological process arising from the excessive production of free radicals in the body. It has the potential to alter animal gene expression and cause damage to the jejunum. However, there have been few reports of changes in the expression of long noncoding RNAs (lncRNAs) in the jejunum in piglets under OS. The purpose of this research was to examine how lncRNAs in piglet jejunum change under OS. Methods: The abdominal cavities of piglets were injected with diquat (DQ) to produce OS. Raw reads were downloaded from the SRA database. RNA-seq was utilized to study the expression of lncRNAs in piglets under OS. Additionally, six randomly selected lncRNAs were verified using quantitative real-time polymerase chain reaction (qRT-PCR) to examine the mechanism of oxidative damage. Results: A total of 79 lncRNAs were differentially expressed (DE) in the treatment group compared to the negative control group. The target genes of DE lncRNAs were enriched in gene ontology (GO) terms and Kyoto encyclopedia of genes and genomes (KEGG) signaling pathways. Chemical carcinogenesis-reactive oxygen species, the Foxo signaling pathway, colorectal cancer, and the AMPK signaling pathway were all linked to OS. Conclusion: Our results demonstrated that DQ-induced OS causes differential expression of lncRNAs, laying the groundwork for future research into the processes involved in the jejunum's response to OS.