LTCC 소재의 조성과 성형 공정에 따른 소결체의 강도 특성

구신일,신효순,여동훈,남산,Gu, Sin Il,Shin, Hyo Soon,Yeo, Dong Hun,Nahm, Sahn 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.1

According to the composition of LTCC material, though it was thought that bulk defect which was made in forming process effects on the densification during the sintering, it was not reported systemically. In this study, we evaluated crystal structure, 3 point bending strength, hardness and microstructure of the samples by uniaxial pressing and tape casting using the commercial powders of the crystallizing glass and the glass/ceramic composite. In the case of glass/ceramic composite, Viox-001 powder with residual glass in the sintering, 3 point bending strength was similar regardless of forming process due to fill the bulk defect by residual glass. In the case of crystallizing glass, MLS-22, because glass phase was small in the sintering, glass did not fill the pore in the sample by uniaxial pressing process, therefore, the 3 point bending strength of it was 167 MPa. However, the 3 point bending strength of the sample by tape casting was 352 MPa and much higher. Meanwhile, crystal structure and hardness were similar regardless of forming process.

Synthesis and size control of CIS powder by the addition of diethylamine in the mechanochemical method

구신일,신효순,여동훈,남산 한양대학교 세라믹연구소 2014 Journal of Ceramic Processing Research Vol.15 No.1

CIS powder has been highly researched as a material for thick-film photovoltaic cells. CIS can be mass produced and synthesized through the mechanochemical method. Despite the simple process, however, the mechanochemical method has been reported to pose a problem with respect to uniformity as it is difficult to control the particle size and there are remnants of unreacted reactants after synthesis. Thus, in this study, diethylamine was added during the synthesis of CIS powder using the mechanochemical method to control particle size and remove excess reactants to obtain uniform powder. An increase of diethylamine during CIS synthesis led to an enhanced wet milling effect, which in turn decreased the powder size. However, at 22.5 wt.% and above, the mechanochemical energy was insufficient for synthesis, resulting in an observation of the raw materials, In, Se and a small amount of CuSe, without the synthesis of CIS.

Anorthite계 LTCC소재에서 Glass 입도와 함량 변화에 따른 강도 특성

구신일,신효순,여동훈,홍연우,김종희,남산,Gu, Sin-Il,Shin, Hyo-Soon,Hong, Youn-Woo,Yeo, Dong-Hun,Kim, Jong-Hee,Nahm, Sahn 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.11

Among LTCC material for substrate, the crystallized anorthite system was mainly studied as high strength material. However, specific factors that have affected on strength of material were studied insufficiently on anorthite system. In this study, the composition of anorthite glass was Ca-Al-Si-Zn-O. The changes of phase and microstructure were observed with the amount and the particle size of glass and the sintering temperature. It was studied that the factors affected on the strength of material. Phases of anorthite and $ZnAl_2O_4$ were formed with the increase of sintering temperature. The $Al_2O_3$ phase was increased with $Al_2O_3$ amount, acted as filler, and the strength of material is increased with $Al_2O_3$ phase. But phases of anorthite and $ZnAl_2O_4$ didn't affect on the strength of material. In the case of 60 vol% glass amounts and below $3.2\;{\mu}m$ of glass particle size, the strength of material was decreased. It is thought that the decrease of strength was due to non-homogeneous mixing between glass powder and filler.

Synthesis of Cu(In1−xGax)Se2 Powder by Using a Metal Source and the Solvothermal Method

구신일,홍승혁,홍연우,여동훈,남산,신효순 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.41

The synthesis of CIGS powder has frequently been studied for use in depositing thick films for solar cell applications. The synthesis of CIGS using a salt source and the solvothermal method has been reported. However, reports on the synthesis using a metal source of relatively low cost are a few. In this study, we selected the solvothermal method and metal sources as raw materials. The effects of the reaction temperature, the mixing of ions, and the Ga source on the phase, the morphology, and the particle size of the powder were observed. For synthesis with a Ga metal source, because the Ga ion, which controls the reaction rate, wasn’t mixed uniformly in the solvent,CIS and small amounts of CIGS were synthesized. When the uniformity of Ga ions was increased by using a rapid stirring process, the CuIn0.6Ga0.4Se2 phase was mainly synthesized. In the case of GaCl3, which has a higher solubility than Ga metal, the CuIn0.4Ga0.6Se2 phase and small amounts of CIS were synthesized. The synthesis of CIGS powder by using a metal source was strongly related to the mixing of Ga ions.

Konus crown 을 이용한 임플란트 보철수복에 관한 연구

권혁신(Hyeog Sin Kweon),구철인(Cheol Ihn Ku),부수붕(Soo Bung Boo) 조선대학교 구강생물학연구소 2000 Oral Biology Research (Oral Biol Res) Vol.24 No.2

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Konus crown 을 이용한 임플란트 보철수복에 관한 연구

권혁신,구철인,부수붕 朝鮮大學校 口腔生物學硏究所 2000 Oral Biology Research (Oral Biol Res) Vol.24 No.2

The retention types of implant prostheses are cementation. screw-tightening and telescopic friction. Implant prostheses retained y telescopic friction type have the advantages of not using cement of screws, being esthetic, and being easy to establish occlusion. Also, they have the advantage of periodontal health because superstructures can be easy to be retrieved. Particularly, they can be used in case of implant fixtures are implanted irregularly, implant fixtures are reveals on supragingiva, and patients have malocclusion tendency. On the other hand, they have defects of technique-sensitivity and expensiveness. Therefore it is considered that implant prostheses retained by telescopic friction should be used cautiously. Thus this study aims to take advantage of telescope in implant prostheses through the manufacture of implant prostheses using telescope.

대두의 모형에 따른 재식밀도가 종실수량 및 수량구성형질에 미치는 영향

構臣漢,安容泰,金侊來,殷鐘旋 韓國作物學會 1973 Korean journal of crop science Vol.- No.14

우리나라 대두의 단위면적당 생산량은 제외국에 비해 낮은 편이며 그 원인은 여러 가지로 생각할 수 있으나 단시일내에 기존품종으로서 생산량을 높이는데 대두 초형에 따르는 재식방법의 개선이 중요하다고 여겨져 중부지방에서의 밀식적응대두형과 밀식정도의 구명을 위해 본 시험이 수행되었다. 본 시험에서는 모형과 각종 형질이 서로 상이한 품종인 장단백목, 충북백, Clark 등 3개 품종이 공시되었으며 휴폭을 세구로 그리고 주간거리를 세세구로 한 3반복으로서 시험하였다. 주당 분지수와 협수는 밀식에 따라 감소되었으나 동일한 밀도에서는 Clark에서 보다 충북백과 장단백목에서 더 많은 분지수를 가지고 있었으며, 협수에 관해서는 휴폭과 주간거리에 유의한 수준의 상호작용이 있었다. 절수는 품종간에 차이가 현저하였으며 휴폭에 의해서는 전혀 변화가 없었으며 주간거리가 커짐에 따라 Clark에서 약간 증가하였다. 간장도 주간거리에 관해서만 유의차가 현저하였으나 절수의 증가와는 관계없이 도장에 기인하였다. 도복성에는 Clark가 가장 강했으며 이는 이 품종 주경의 탄력성 때문인 것으로 여겨졌다. 밀식조건하에서는 다지성이고 광엽성인 재래품종들보다 절수가 많고 초장이 큰 도입품종 Clark가 공시된 3개 품종중 가장 수량이 많았으며 밀식재배용으로의 가장 알맞은 초형임이 명확하였고 파종은 재래식 점파보다는 조파로 밀식함이 노력이 절약되고 단위면적당 수량도 현저히 증가될 것이다. This study was conducted to determine optimum canopy type for dense planting with three soybean varieties possessing different types of canopy. The experimental plots were arranged in split-split plot design. Branches and pods per plant were both reduced by close planting, particularly keen responses were observed in the variety Clark. Number of nodes per plant seems a characteristics of each variety and was independent character from the plant height. Clark, tall variety, was most resistant to lodging and it may be due to the elasticity of the stem. Seed yields of Jangdan-Baikmok, branching type, tended to be lower at the dense spacing, whereas, branchless type variety Clark was higher in seed yield at the dense planting. These results indicate that the plant type possessing more nodes and less branching per plant with be suitable for dense planting.

멀티빔 센서를 이용한 사이드 스캔 소나 개발에 관한 연구

장유신(Y.S. Chang),계중읍(J.E. Keh),구융서(Y.S. Koo),박승수(S.S. Park),김지한(J.H. Kim),이만형(M.H. Lee) 한국정밀공학회 2004 한국정밀공학회 학술발표대회 논문집 Vol.2004 No.10월

A side scan sonar system uses the towfish installed sonars, it is an equipment that search images of the bottom surface of the sea in real time. It is a typical equipment that is related to a sea investigation such as a geological survey, seabed communication cable and power line cable placing repair investigation, fish breeding ground investigation, sea purification, relic and mineral investigation, and mine and submarine search. It used to find objects and investigate on the seabed surface. But, recently, it is used to sea purification and geological survey that require information of the correct surface of the seabed. So, it needs various filtering technique and image processing techniques development to acquire high resolution image. Therefore, this research develops a side scan sonar using multi-beam sensors that supply various information with the fast scan speed and correct high resolution that is not a simple underwater investigation equipment.

적층 평판형 SOFC 모듈에서 소결 시 전해질 층의 휨 현상

오민욱,구신일,신효순,여동훈,Oh, Min-Wook,Gu, Sin-Il,Shin, Hyo-Soon,Yeo, Dong-Hun 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.3

A layered planer SOFC module was designed from planar-type SOFC. It was prepared by multi-layered ceramic technology. To form the cathode and the anode in the layered structure, reliable channels should be made on the both side of electrolyte perpendicularly. However, monolithic SOFC using multi-layered ceramic technology hasn't been studied another group, and the warpage of electrolyte in the channel, also, hasn't been studied, when electrode is printed on the electrolyte. In this study, the channels are prepared with electrode printing, and their warpage are evaluated. In the case of YSZ without electrode, the warpages are nothing in the limit of measurement using optical microscope. The warpage of 'YSZ-NiO printed' increases than that of 'NiO printed', and also, the case of 'double electrode printed' is similar to 'YSZ-NiO printed'. It is thought that, in the printed electrolyte, the warpage is related to the difference of the sintering behavior of each material.

Synthesis and Low-temperature Sintering of CuInSe2-CuGaSe2 Powders

홍승혁,구신일,여동훈,김종희,신효순,남산 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.41

A solar cell with a compound semiconductor CuInSe2-CuGaSe2 (CIGS) battery fabricated using the thin film process has weak points in that the unit cost is high and the process is complicated. To solve these problems, the screen printing method, a process for manufacturing the wide-absorbing layer of a Ⅰ-Ⅲ-Ⅵ2 compound semiconductor solar battery with ease and low cost, has been researched. Synthesis of a nano-sized homogenous CIGS powders is needed for firing of thick film formed at low temperature, and for this, the solvothermal method has been adopted. However,present, it’s difficult to obtain accurate CIGS composition, and phase uniformity for mixtures of CIS, CGS, and CIGS has been obtained. In this study, homogenous CIS and CGS powders were synthesized by using the solvothermal method with CuCl, InCl, GaCl, and Se powders and diethylamine solvent. The paste for screen printing was prepared by mixing CIS and CGS powders whose sizes were about 0.3 μm and the CIGS layer was formed by using a printing process and firing. As a result, it’s confirmed that CuIn0.7Ga0.3Se2 was formed at 900 ℃ and that volatilization of Se ions was controlled by using Se powder at atmospheric pressure during the sintering.