• Journal of the Korean Ceramic Society
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• v.40 no.11
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• pp.1085-1089
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• 2003

In the present study effects of SnO$_2$-impregnation on the cell performance of Mesocarbon Microbeads (MCMB) electrode in the Li-ion battery have been investigated. Sn element was impreganted into MCMB powders by the chemical titration, and then post annealed at 250$^{\circ}C$ for 1 h in ambient atmosphere to be transformed as tin-oxide. From the measurement for the cell performance with the half cell in which the SnO$_2$-impregnated MCMB was used as an anode, the SnO$_2$-impregnated MCMB showed higher charge/discharge capacities, higher reversible specific charge capacity and better cycleability than a raw MCMB. As the amount of impregnated SnO$_2$ increased, both reversible and irreversible capacities increased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.10
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• pp.79-83
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• 1971

To investigate the effects of seed treatments and liming on nodulation and growth of lucerne(Medicago sativa L.) in an upland yellow-brown earth in N.Z. the five levels of seed treatments(Uninoculated, Inoculated, Inoculated plus lime pelleted, Inoculated plus 50/50 phosphate/dolmite pelleted, Inoculated plus ta1c pelleted), and 2 levels of lime applications (0, 25kg/10a) were compared and their interactions were observed, and then the following results were obtained. 1. In oder to obtain the effective nodulation of lucerne on acid soil it is usually necessary to apply lime and inoculate the seed. 2. The coating of inoculated lucerne seed with adequate materials will promote the nodulation. 3. The pelleting of lucerne seed may be a of reducing the need for the heavy liming. 4. The finely grounded lime was the best to use origin upland yellow-brown earth. 5. When the seed were not inoculated or pelleted with inferior material, liming is very effective for the nodulation and growth of lucerne. 6. The pelleting seed will reduce the laborious work and expenditure.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.1
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• pp.1-8
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• 2012

Since the cement industry is expected to face serious setbacks in the near future associated with environmental concerns. With the advent of new technologies and increased public awareness about global environmental issues, the cement industry is actively seeking to adopt new technologies as part of an effort to diversity its resources. This study is designed to assess the fundamental properties of zeolite cement concrete which consists mainly of natural zeolite, which is known for removal of and harmful gas, ion exchange capacity removing cation contaminant including heavy metals and ammonia, absorptive capacity and molecular sieving effect together with excellent insulation capacity as a porous material, and recently draws much attention for its possibility as an alternative material to cement. The study was conducted to show the compressive strength of concrete, slump, bleeding and air volume according to the changes of natural zeolite and alkali activator(NaOH). As a result of measuring the compressive strength of natural zeolite concrete, it was almost 40MPa and displayed similar to general concrete in the tests of slump, bleeding and air volume, with which it was considered that it may be used as a future high performance, high performance construction material.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.401-401
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• 2007

내장 전압의 측정은 전기흡수 방법과 변조 광전류 분광학을 이용하는 방법이 있으며, 우리는 이 논문에서 변조 광전류 분광학을 사용하여 내장 전압을 측정하였다. 소자에 인가 전압이 영일 때 양극과 음극의 일 함수 차이 때문에 내장 전압이 존재하며, 그로 인해 내장 전기장이 생긴다. 유기 발광 소자의 광전도도는 엑시톤이 자유전자와 정공으로 분리들 때 발생한다. 이 때 발생되는 광전류와 광전류의 위상 변화를 측정하여 내장 전압을 추정한다. 소자의 구조는 두 전극 사이에 단층으로 하여 만들었으며 모든 소자의 $Alq_3$ 두께는 150nm로 하고, 양극은 ITO를 사용하였고 음극은 Al과 LiAl을 100nm 두께로 하였다. 내장 전압의 측정 결과 ITO/$Alq_3$/LiAl의 내장 전압은 0.9eV로 측정된 데 반해 ITO/$Alq_3$/LiAl은 1.6eV로 측정되었다. 따라서, LiAl을 사용한 소자의 경우 Al을 사용한 소자에 비해 내장 전압이 0.7eV 증가되었다. 이는 LiAl의 일함수가 Al보다 낮은 값을 갖는 것과 일치하는 결과이다. 이런 결과가 나온 까닭은 LiAl을 음극으로 사용한 경우에는 자유로운 $Li^+$이 발생하여 유기물에 더 좋은 전자주입이 되도록 하여 소자의 전자 장벽을 낮추었기 때문에 전자의 주입이 활발하여 광전류의 이동이 용이했음을 알 수 있다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.333-334
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• 2007

Diamond-like carbon (DLC)박막은 높은 경도, 화학적 안정성, 높은 광 투과성을 가지고 있어, 공구강, 광학렌즈 및 플라스틱의 보호 코팅을 위해 응용되어진다. 본 연구에는 DLC 박막은 Silicon을 기반으로 하는 태양전지 반사 반지막으로 응용을 위해, 13.56 MHz RF 플라즈마 화학기상 증착 (RF-PECVD)법을 통해 합성되었다. DLC 합성 시 RF power는 150 W, 메탄 (CH4)가스의 유량은 6%~10% 조절되었다. 합성되어진 DLC 박막의 광학적 특성은 UV spectrometry, Ellipsometry를 사용하여 분석되었고, 경도는 Nano-indenter를 사용하여 측정되었다. 측정 결과 투과도와 굴절률 등의 광학적 특성은 탄소 조성비가 6%정도에서 가장 좋은 결과 값을 얻었으나, 물리적 특성인 경도는 탄소 조성비가 높을수록 증가하는 경향을 보였으며, Si기판과의 접착력은 32N 이상의 높은 값을 나타내었다. 결과로써, DLC 박막은 합성시 적절한 탄소 조성비를 통해 silicon을 기반으로 하는 태양전지 반사방지막으로 응용할 수 있다.

• Journal of Korean Society of Steel Construction
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• v.10 no.1 s.34
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• pp.37-45
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• 1998

The relational database system on fatigue strength was constructed, and the properties of fatigue life distribution were examined to analyze reliability and safety of metallic materials. Data manipulations were efficiently performed in relational fatigue strength database system using dependency diagram. Regardless of the distribution of fatigue strength, the proposed method, the Robust method and the complementary error function method using probability distribution, successfully estimated parameters of the 3-parameter Weibull distribution. The proposed criterion for estimating non-failure probability showed good results regardless of censoring time. The fatigue life distribution function described as a function of parameters of the Weibull distribution and applied stress ratio produced P-S-N characteristics reasonably.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.209.1-209.1
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• 2013

GaP는 가시광선 발광다이오드을 얻을 수 있는 적절한 재료중의 하나로 해당영역의 파장에 대하여 높은 양자효율을 얻을 수 있고, 깊은 준위 재결합이 없기 때문에 GaP 녹색 및 As 첨가한 GaAsP 적색 LED 에 적용할 수 있습니다. 또한, 상온에서 2.2 eV 에 해당하는 넓은 에너지 밴드갭을 가지고 있으므로, 소음이 없는 자외선 검출기에도 적합합니다. 이 물질에 대한 소자들은 기존에 GaP 기판을 사용하였습니다. 최근, GaP 와 격자상수가 비슷한 Si 기판을 활용하여 그 위에 성장하는 방법에 대한 관심이 많아졌습니다. Si는 물리적 및 화학적으로 안정하고 딱딱한 소재이며 대면적 기판을 쉽게 얻을 수 있어 전자 기기 및 대규모 집적 회로의 좋은 소재입니다. Si 와 대조적으로 GaP은 깨지기 쉬운 재료이며 GaP 기판은 Si와 같은 대면적 기판을 얻을 수 없습니다. 이러한 문제의 한 가지 해결책은 Si 기판위에 GaP 층의 성장입니다. GaP 과 Si의 조합은 현재의 광전소자 들에 더하여 더 많은 응용프로그램들을 가능하게 할 것입니다. 그러나, Si 기판위에 GaP 성장 시 삼차원적 성장 및 역위상 경계면과 같은 문제점들이 발생하므로 질이 높고 균일한 결정의 GaP 를 얻기가 어렵습니다. 따라서, Si 에 GaP 의 성장시 초기 단계를 제어하는 성장 기술이 필요합니다. 본 연구에서는, 유기금속화학증착법을 이용하여 Si 기판위에 양질의 GaP를 얻을 수 있는 최적의 성장조건을 얻고자 합니다. 실험 조건은 Si에 GaP의 에피택셜 성장의 초기 단계에 영향을 주는 V/III 비율, 성장압력, 기판방향 등을 가변하는 조건으로 진행하였습니다. V/III 비율은 100~6400, 성장 압력은 76~380 Torr로 진행하였고, Si 기판은 just(001)과 2~6도 기울어진 (001) 기판을 사용하였습니다.

• Journal of Korean Society of Forest Science
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• v.47 no.1
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• pp.27-36
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• 1980

To establish an easy classification method of bamboos observation of the shapes of vascular bundle sheath of Sasa, one of the important natural resources available in Korea, was made on the basis of vascular bundle sheath of bamboo culms because Sasa has a unique vascular bundle sheath as discussed by Grosser and Liese et al. Morphological characteristics of Saw observed are summarized as follows: 1. The thickness of culm wall showed no distinctive difference between upper and low parts of culms of Sasa grown at the ground level. 2. In relation to the taxonomical classification of bamboo, Sasa showed a and a' type but did not e.f.h. and e' type was not identified. 3. Two typical types of bamboo vascular bundle sheath, i.e. b.c.d.e. and g type and d and e type, were found in Sasa but sometimes b.c.g. type was not observed. 4. The results mentioned above seem to be an important key for classification of Sasa.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.1
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• pp.25-32
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• 2022

Investment casting is a production method commonly used to manufacture precision equipment, medical fields, and accessories, and has continued to develop through the modernization of equipment and high quality of materials, and its scope of use has been expanded. The purpose of this study is to minimize the defect rate by deriving structural improvement and standardization of mold temperature, which are key elements of the investment casting process, to minimize the defect rate. The scope of the study is limited to jewelry manufacturing casting processes suitable for understanding the structure and principles of small gate, and an experimental research is to be conducted by using soft Wax, gypsum powder, and 14 K gold as research materials. According to the results, the most appropriate casting standard temperature for the casting pattern of Alloy 14 k was the lowest turbulence at 980℃ flask temperature of 550℃, so good products could be produced. As a future task of this study, detailed studies are needed to data the structure and system temperature of small gate, reduce production defects in the field, and provide data for excellent investment casting competitiveness.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.50-54
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• 1999

Plasma display panel is a potential candidate for HDTV, due to the fact that the screen size can easily be increased by a thick film technology. In this study, transparent dielectric materials which satisfied the requirements of dielectrics for PDP was developed using lead alumina borosilicate glasses. The Paste which had thixotropic behavior suitable for screen printing was made of this glass composition. the paste became more thixotropic as the particle size decreased. After firing, the cross sectional area of the thick film was analyzed by SEM. The voids in the thick film were removed using bimodal particle system. The dielectric thick film showed good adhesion characteristics.