• Proceedings of the KIEE Conference
• /
• 2015.07a
• /
• pp.1171-1172
• /
• 2015

송전선이나 전기기기의 나선(裸線)부분을 절연하고 동시에 기계적으로 유지 또는 지지하기 위한 절연체와 이것과 일체로 조립된 금구류로 구성된 절연지지물인 애자는 전기적으로 충분한 절연내력을 가지게 하기 위하여 다수의 주름을 만들어 표면에 따른 거리를 크게 한다. 이는 표면이 습하였을 때, 염분이나 먼지 등이 부착하였을 때 절연내력이 저하되는 것을 방지하는 데 효과가 있다. 그리고 재질별(세라믹, 유리, 합성수지 등), 모양별(원판형, 원주형, 중공, 갓형 등), 용도별(전차 선로용, 발전소 또는 변전소용, 통신 선로용 등) 및 사용방법(현수용, 내장용, 인류용, 고정용 등)에 따라 다양하게 분류된다. 본 논문에서는 복합 애자류(composite insulators)의 여러 가지 성능평가 시험방법 중에서 복합 애자의 여러 계면과 연결 금구의 접속부(interfaces and connections of end fittings)에 대한 이상 유무를 확인하는 시험인 수분침투시험평가기술에 대해 고찰하였다.

• Composites Research
• /
• v.21 no.3
• /
• pp.18-23
• /
• 2008

The Rapid Prototyping (RP) technology has advanced in many application areas. In this research, implantable Drug Delivery System (DDS) was fabricated by an RP system, Nano Composite Deposition System (NCDS). The DDS composite consists of 5-fluorouracil (5-FU), as drug particles, and PLGA85/15 as biodegradable polymer matrix. To have larger surface area, the DDS was fabricated in a scaffold shape, and its degradation was tested in vitro environment. Biocompatible Hydroxyapatite (HA) powders were added to the drug-polymer composite in order to control drug release. Test results showed a possibility of controlled release of scaffold DDS over 50 days.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.15 no.5
• /
• pp.367-379
• /
• 2022

In this paper, a multilayer radar absorbing structure was designed using the Particle Swarm Optimization (PSO) algorithm, and the characteristics of the multilayer radar absorbing structure were analyzed. It was shown that design values can be derived quickly and accurately by applying PSO to the design of a multilayer radar absorbing structure, and it is also shown that the optimal multilayer radar absorbing structure can be designed especially for an oblique incident. In addition, it was shown that the optimal value that meets the performance requirements can be determined even in a combination of various design parameters. It is presented through a comprehensive flowchart including the equations and detailed descriptions of all variables for each step. From the results of this paper, it is possible to omit complex and many calculations for designing a multilayer radar absorbing structure, and it is possible to use various composite materials. It can be utilized in the design and development of multilayer radar absorbing structures.

• Transactions of Materials Processing
• /
• v.14 no.7 s.79
• /
• pp.587-594
• /
• 2005

분무성형공정은 급냉응고 및 결정입자 제어에 따른 고품위 소재 개발의 장점과 함께 고밀도 near-net-shape 제품의 제조가 가능한 합금제조기술이다 분무성형체의 미세조직은 적층표면에 도달하는 액적들의 평균 열용량, 즉 고상분율에 의하여 결정되며, 이는 액적의 비행과정에서의 분사가스-액적간의 열전달과 적층표면에서의 열유입과 열유출 속도에 영향을 받는다. 실제 다양한 공정변수들이 복합적으로 미세조직 형성과정에 영향을 미치지만, 균일한 미세조직을 얻기 위하여서는 적층표면에서의 온도와 고상분율을 항상 일정하게 제어하여야만 한다 즉, 적층표면 온도를 분무 성형공정중에 지속적으로 측정하여 이를 공정 제어 시스템에 feedback하여 원하는 적층표면온도를 유지하도록 공정변수를 제어하는 것이 필수적이다. 분무성형에 제조된 성형체는 합금원소의 편석이 없고 미세한 등방성의 결정립으로 이루어진 특징적인 미세조직을 나타낸다 이와 같은 미세조직으로 인하여 분무성형체는 우수한 성형성과 기계가공성을 나타내며, 또한 분무성형-후속가공된 최종 제품은 잉곳주조에 의하여 제조된 것과 비교하여 크게 향상된 기계적 성질을 가진다.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2009.10a
• /
• pp.141-141
• /
• 2009

EHD(electrohydrodynamic) 증착법을 적용하여 코팅층 표면복합구조제어를 연구하였다. 이 방법을 이용하여 표면구조 제어를 통한 친/소수 코팅층 개발의 제반 조건들을 탐색한다. 화학적으로 안정한 코팅층을 형성할 수 있는 전구체 물질을 용매에 혼합하고, 전구체 물질의 농도를 조절하여 다양한 점도의 용액을 합성하고, 전기장을 적절한 범위에서 변화시키면서 용액의 점도와 전기장의 변화에 따른 코팅층의 표면형상을 체계적으로 조사하고, 주요 공정 변수인 용액 전구체농도와 전기장에 따른 표면형상 변화에 대한 공정 MAP을 조사하여 초친수/초발수 특성을 나타내는 최적 표면구조를 예측한다.

• Composites Research
• /
• v.16 no.3
• /
• pp.1-8
• /
• 2003

Densification occurs by the inelastic flow of the matrix materials during the consolidation processes at high temperature for MMCs, and the results depend on many process conditions such as applied pressure, temperature and volume fraction of fiber and matrix materials. This is particularly important in titanium matrix composites since material failure may occur by either the applied conditions or microstructural parameters through the processes, and thus a generic model based on micro-mechanical approaches enabling the evolution of density over time to be predicted has been developed. The mode developed is then implemented into FEM so that practical process simulation has been carried out. Further the experimental investigation of the consolidation behavior of SiC/Ti-6Al-4V composites using vacuum hot pressing has been performed, and the results obtained are compared with the model predictions.

• Membrane Journal
• /
• v.33 no.5
• /
• pp.240-247
• /
• 2023

Even among gas separation methods, CO₂ capture and separation via membranes is an ever-growing field, with many different membrane compositions continually being developed. Ionic liquid (IL) based composite membranes show excellent performance values in separating CO₂. Similarly, various copolymer/IL composite membranes also display improved performance. The addition of fillers such as graphene oxide to these copolymer/IL composite membranes shows a further enhanced version of these fillers, most likely due to the strong interactions that occur between ILs and organic fillers, which consequently improves factors such as the affinity, selectivity, and adsorption of CO₂. Copolymer/IL composite membranes utilizing a metal-organic framework (MOF) showed improved CO₂ permeability. This review discusses the study of various combinations of ionic liquid and copolymer composite membranes for carbon dioxide separation.

• Journal of Chest Surgery
• /
• v.30 no.5
• /
• pp.493-500
• /
• 1997

We performed this study to evaluate hepatic venous drainage in atrial isomerism by MR and the clinical significance of anomalous hepatic venous return in total cavopulmonary shunt operation. Numbers and locations of hepatic veins in twenty-two patients with isomerism(thirteen with right isomerism and nine with left isom rism) were evaluated by MR. Operative procedure of hepatic veins and postoperative arterial oxygen saturation were compared with hepatic vein connection in six patients after total cavopulmonary shunt operation. Among nine patients with left isomerism, hepatic venous return was totally anomalous via a single opening in eight, and via two separate openings in one. Among thirteen patients with right isomerism, partial anomalous hepatic venous connection directly to the atrium was seen in four. One showed total anomalous hepatic venous connection to atrium through one opening. Total cavopulmonary shunt operation was performed in 6 patients. Hepatic veins were connected to pulmonary arteries in four patients who had one atrial opening of hepatic vein andlor IVC, or two ipsilateral atrial opening of hepatic veins and IVC. In conclusion, hepatic vein drainage to atrium is variable in atrial isomerism. MR is useful for evaluation of hepatic vein drainage in atrial isomerism and surgical pla ning.

• Composites Research
• /
• v.14 no.4
• /
• pp.8-14
• /
• 2001

The satellite system experiences severe mechanical loads during the launch period. Therefore, the positive margin of safety of the satellite system must be demonstrated for every possible mechanical loading conditions during the launch period. This paper presents modal and stress analysis results due to quasi-static loads for the satellite antenna system. The failure tendency fur the sandwich construction of the satellite antenna system has been studied with various lamination angles of unidirectional prepreg.

• Journal of Plant Biotechnology
• /
• v.37 no.1
• /
• pp.12-24
• /
• 2010

Plant metabolomics is a research field for identifying all of the metabolites found in a certain plant cell, tissue, organ, or whole plant in a given time and conditions and for studying changes in metabolic profiling as time goes or conditions change. Metabolomics is one of the most recently developed omics for holistic approach to biology and is a kind of systems biology. Metabolomics or metabolite fingerprinting techniques usually involves collecting spectra of crude solvent extracts without purification and separation of pure compounds or not in standardized conditions. Therefore, that requires a high degree of reproducibility, which can be achieved by using a standardized method for sample preparation and data acquisition and analysis. In plant biology, metabolomics is applied for various research fields including rapid discrimination between plant species, cultivar and GM plants, metabolic evaluation of commercial food stocks and medicinal herbs, understanding various physiological, stress responses, and determination of gene functions. Recently, plant metabolomics is applied for characterization of gene function often in combination with transcriptomics by analyzing tagged mutants of the model plants of Arabidopsis and rice. The use of plant metabolomics combined by transcriptomics in functional genomics will be the challenge for the coming year. This review paper attempted to introduce current status and prospects of plant metabolomics research.