• Plant Resources
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• 제6권1호
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• pp.53-56
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• 2003

To develop optimal storage method of root of Anemarrhena Rhizome, which has been grown as major cultural herbal medicine material, root of Anemarrhena Rhizome was stored for 10 months with different packing materials and sealing methods. The loss in dry weight as influenced by packing materials and sealing methods was the lowest at vacuum packing and followed by complete sealing methods with transparent polyethylene film. The rot ratio of root during the storage period was not significantly different among packing materials but was significantly different among sealing conditions. Conclusively vacuum packing and complete sealing with polyethylene film appears to be optimal for storage of Anemarrhena Rhizome.

• Plant Resources
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• 제5권2호
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• pp.114-117
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• 2002

To develop optimal storage method of root of Peucedani Radix, which has been grown as major cultural herbal medicine material, root of Peucedani Radix was stored for 10 months with different packing materials and sealing methods. The loss in dry weight as influenced by packing materials and sealing methods was the lowest at vacuum packing and followed by complete sealing methods with transparent polyethylene film. The ratio of root rot during the storage period was not significantly different between packing materials but was significantly different between sealing conditions. Conclusively vacuum packing and complete sealing with polyethylene film appears to be optimal for storage of Peucedani Radix.

• Progress in Superconductivity
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• 제1권1호
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• pp.56-60
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• 1999

Ultra fine MgO particles added BSCCO tapes were fabricated by tape casting using Doctor Blade Method and enclosed by silver foil for different starting compositions (that is, 2223 major, 2212 major). In order to obtain optimum microstructure, thermomechanical treatment was done. Microstructure and phase were analyzed by XRD, SEM and DTA. The critical current density was measured under magnetic field at 77K. The tapes fabricated from the precursor powder with BSCCO-2223 phase (>90%) result in a microstructure with a larger grain size and higher transport critical current density value under magnetic field at given thermomechanical treatment conditions.

• 접착 및 계면
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• 제3권3호
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• pp.1-6
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• 2002

본 연구에서는 고무 재료의 설계 인자 중 어떤 것이 소음에 주된 영향을 주는지 검토하였고, 저소음 타이어 개발을 위한 고무 재료의 설계 방향을 제시하였다. 소음은 무향실 타이에 소음과 고무 시편의 충격 소음을 측정하였고, 고무 시편의 물성은 경도, 인장 물성 및 동적 점탄성을 측정하였다. 타이어 소음에 영향을 주는 고무 재료의 주된 설계 인자는 경도 또는 300% 모듈러스이고 양자간에는 정의 상관관계가 있다. 따라서 고무 재료의 경도 또는 300% 모듈러스를 낮게 설계하면 소음을 저감시킬 수 있다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 춘계학술발표대회
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• pp.47.1-47.1
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• 2009

Nanostructured biomaterials have increased those potential for utilizing in many medical applications. In this study, benefit of nanotechnology for the response with biological targets will be described in terms of size, effective surface area and surface energy (physical aspect). Also, correlations between physical and biological interactions (greater protein adsorption on nano surface roughness) will be discussed for understanding biocompatibility of nanostructured biomaterials including carbon nanotube composites and nanostructured titanium surfaces. In the application parts, various major tissue cells, such as bone, cartilage, vascular and bladder cell responses will be discussed with suggested nanomaterials. Lastly, immune responses with macrophage (adhesion and several major cytokines) on nanostructured biomaterials will be described for evasive immune response.

• 대한금속재료학회지
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• 제48권2호
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• pp.180-186
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• 2010

For the application of field emission display (FED), it is essential to develop a carbon nanotube (CNT) cathode with high emission current density. In this study, we developed and demonstrated a post-heat treatment (PHT) process to improve field emission properties of CNT cathodes. Since the PHT is intended to burn out organic materials covering the CNTs, the PHT was carried out by heating samples at a high temperature in an atmosphere. The PHT process is applied for samples processed by surface treatment with an adhesive tape. Compared to samples prior to the PHT, samples after the PHT at $360^{\circ}C$ showed about 17% improvement in emission current density. The major reason for the increased current density is mainly the increased aspect ratio of the CNTs because of the removal of the adhesive organic residues covering the CNTs, which were attached on the CNT surfaces during the surface treatment using the adhesive taping method.

• 한국초전도ㆍ저온공학회논문지
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• 제12권4호
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• pp.8-12
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• 2010

The properties of the conductor.mechanical, thermal, and electrical-are the key information in the design and optimization of superconducting coils. Particularly, in devices using second generation (2G) high temperature superconductors (HTS), whose base materials (for example, the substrate or stabilizer) and dimensions are adjustable, a design process for conductor optimization is one of the most important factors to enhance the electrical and thermal performance of the superconducting system while reducing the cost of the conductor. Recently, we developed a numerical program that can be used for 2G HTS conductor optimization. Focusing on the five major properties, viz. the electrical resistivity, heat capacity, thermal conductivity, Z-value, and enthalpy, the program includes an electronic database of the major base materials and calculates the equivalent properties of the 2G HTS conductors using the dimensions of the base materials as the input values. In this study, the developed program is introduced and its validity is verified by comparing the experimental and simulated results obtained with several 2G HTS conductors.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제25권2호
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• pp.361-379
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• 2011

본 연구는 대학의 전자공학과 학생들을 대상으로 수학 교과 내용과 전공 교과 내용의 연관성 및 수학교과 내의 선수 학습 내용과의 연관성을 이용한 공업수학 학습자료를 개발하고 이를 활용한 수학학습의 효과를 알아보는데 목적이 있다. 이러한 목적을 위해 먼저 전자공학과 전공 학습을 위해 필요한 공업수학 내용의 목록을 작성하고 이를 바탕으로 선수학습 내용 및 전공교과 내용과의 연관성을 조사한 후 연관성이 있는 내용을 학습자료의 주제로 선정하여 학습자료를 개발하였다. 그리고 개발된 학습자료를 이용하여 학습하게 한 후 학습자료에 대한 반응을 조사하고, 학습 태도에 대한 효과를 분석하였다. 그 결과, 학습자료의 도입부에 기술된 전공내용은 학생들에게 공업수학 학습에 대한 동기 부여에 도움을 주었으며, 공업수학 학습 내용 전에 기술된 선수학습 내용은 학생들에게 공업수학 학습내용의 학습에 집중하는데 도움을 주었다. 또한 개발된 학습자료는 학생들의 수학 학습 태도 중 수학 학습에 대한 자신감을 향상시키는데 효과가 있는 것으로 나타났다.

• 한국전기전자재료학회논문지
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• 제36권3호
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• pp.292-297
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• 2023

Triboelectric devices are attracting attention from researchers as self-powered electronic systems that can instantly convert mechanical input into electrical energy output. To improve triboelectric energy harvesting performance, increasing the number of contacts as well as the contact area has been carried out by numerous researchers. In this study, we design a shaker-type energy harvester which is called as maracas triboelectric generator (M-TEG), inspired by the structure of maracas, one of the musical percussion instruments. A tripod frame is inserted to the inside of a cylindrical case, which is a device with the electrodes of aluminum and copper. Then, the triboelectric energy harvesting characteristics between polypropylene (PP) balls and the electrodes are measured. The M-TEG with the frame generates the energy harvesting signals up to ~100 V and ~2.5 ㎂ due to larger contact area and numbers, which enhances the voltage and current output by 250% and 610% compared to that without the frame, respectively. This study presents the feasibility of self-powered sensors and toys using improved triboelectric energy performance with a low-cost and simple manufacturing process in the interesting structure.

• Journal of the Korean Wood Science and Technology
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• 제34권1호
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• pp.32-39
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• 2006

본 연구는 현악기에 사용되는 현악기용 도료가 현악기의 음향성능에 미치는 영향을 조사하였다. 음향분석장치(FFT)를 이용하여 목재악기용 도료의 도막두께에 따른 음향적 성능을 평가하였다. 목재악기용으로 사용된 도료는 악기용 우레탄계 상도도료, 오일 스테인계 도료, 자외선 경화형 에폭시 도료이다. 형성된 도막의 음향적인 특성은 FFT 분석기에서 측정된 공명주파수와 댐핑값(damping factor)으로부터 동적탄성계수와 전단탄성계수를 계산하여 얻고, 밀도와의 관계와 탄성계수간의 관계를 통하여 도막의 두께에 따른 음향적인 특성을 측정하고 비교분석하여 상관관계를 조사하였다.