The rheological behavior of a cordierite honeycomb extrusion paste was investigated by measuring torque values in a Brabender plastograph. The extrusion pastes were formulated using binder (methy cellulose, MC), solvent (water), plasticizer (ploy ethylene glycol, PEG) and lubricants (oleic acid, OA). The mixing sequence and optimum organic binder, at least for homogeneous mixed state, can be determined from the rheological point of view. 3%MC-30%-1.5%PEG-1.0%OA with respect to the cordierite powder was chosen as a binder composition for the extrusion process of cordierite powder.

based composites are candidate materials for ultra-high temperature materials (UHTMs). has become an indispensable ingredient in UHTMs, due to its high melting temperature, relatively low density, and excellent resistance to thermal shock or oxidation. powders are usually synthesized by solid state reactions such as carbothermal, borothermal, or combined carbothermal reaction. SiC is added to this system in order to enhance the oxidation resistance of . In this study, ?based composites were successfully synthesized and densified through two different processing paths. or 25 vol.%SiC was fully synthesized from oxide starting materials with reducing agents after heat treatment at 1400. Besides, ?20 vol.%SiC was fully densified with as a sintering additive after hot pressing at 1900. The synthesis mechanism and the effect of sintering additives on densification of ?SiC composites were also discussed.

In this study, the feasible test for the mechanical property characterization of ceramics and multi-layer ceramic capacitor(MLCC) was performed with nanoindentation technique. In case of ceramics, hardness and elastic modulus are dependent on the densification of specimen showing the highest hardness and elastic modulus values of 12.3 GPa and 155 GPa, respectively at . In case of MLCC chip, hardness of dielectric layer was lower than that of margin region. The nanoindentation method could be useful tool for the measurement of mechanical property within dielectric layer of very thin thickness in high capacitance MLCC

Ti(C,N) solid solutions in hot-pressed Ti() (x=0.0, 0.3, 0.5, 0.7, 1.0) and 40TiC-40TiN-20Ni (in wt.%) cermet were characterized in this study. For hot-pressed Ti(C,N)s, the lattice parameters and hardness values of Ti(C,N) were determined by using XRD (X-Ray Diffraction) and nanoindentation. The properties of hot-pressed Ti(C,N) samples changed linearly with their carbon or nitrogen contents. For the TiC-TiN-Ni cermet, the hardness of the hard phase and binder phase were determined by nanoindentation in conjunction with microstructural observation. The measured hardness values were GPa for the binder phase and GPa for the hard phase, which was close to the hardness of hot-pressed Ti().

The indentation technique has been one of the most commonly used techniques for the measurement of the mechanical properties of materials due to its experimental ease and speed. Recently, the scope of indentation has been enlarged down to the nanometer range through the development of instrumentations capable of continuously measuring load and displacement. In addition to testing hardness, the elastic modulus of submicron area could be measured from an indentation load-displacement (P-h) curve. In this study, the hardness values of the constituent phases in Ti()-NbC-Ni cermets were evaluated by nanoindentation. SEM observation of the indented surface was indispensable in order to separate the hardness of each constituent phase since the Ti()-based cermets have relatively inhomogeneous microstructure. The measured values of hardness using nanoindentation were GPa for hard phase and GPa for binder phase. The effect of NbC addition on hardness was not obvious in this work.

doped (GDC) solid solutions have been considered as a promising materials for electrolytes in intermediate-temperature solid oxide fuel cells. In this study, the nano-sized GDC powder with average panicle size of 69nm was prepared by a high energy ball milling process and its sintering behavior was investigated. Heat-treatment at of nano-sized GDC powder mixture led to GDC solid-solution. The enhanced densification over 96% of relative density was obtained after sintering at for 2h. It was found that the sinterability of GDC powder could be significantly improved by the introduction of a high energy ball milling process

버섯유전체 완전해독연구는 세계적으로 식용버섯(느타리, 송이), 약용버섯(영지, 치마버섯), 독버섯(광대버섯)등에 대하여 시작단계에 있다. 국내에서는 식물세균병인 벼 흰잎마름병원균의 유전체염기서열을 완전해독(생공원)함으로써 미생물 유전체 연구기반 기술을 확보하고 있으나 진균은 종에 따라 다양한 유전체 크기를 가지고 있고 반복배열 DNA가 다수 존재하며 다양한 chromosome형이 분포하는 등으로 염기서열 분석에 어려움이 예상되어 새로운 원천기술의 정립이 필요하다. 농업과학기술원에서는 국내토종 식용버섯 유전체 연구 대상을 팽이로 선정(2007.01.30)하고 농업생명공학연구원, (주)마크로젠 연구팀에 의한 유전체 완전염기서열 해독 연구와 건국대학교, 한경대학교 연구팀과 버섯유전체의 기능분석을 위한 연구기반을 확보하기 위하여 바이오그린21사업의 유전체 개발이용연구단 과제를 4년간 수행하게 되었다. 과제의 구성은 팽이버섯 유전체 완전해독연구를 위하여 농업생명공학연구원에서 국내에서 수집된 팽이균주(KACC42777)를 대상으로 염색체분리 및 핵형분석을 수행하고 physical map 작성 및 유전자은행(BAC library)을 제작하고, (주)마크로젠에서 팽이버섯 유전체의 염기서열 해독 및 생물정보 분석을 수행하게 된다. 기능유전체연구로 농업과학기술원에서 형질전환을 이용한 변이체 pool을 작성하고, 건국대학교에서 팽이버섯의 발생단계에 따른 전사산물 구조 및 발현에 대한 연구, 한경대학교에서 팽이버섯 유전체 기능분석을 위한 Target 유전자 파괴 및 과발현 시스템을 구축하는 연구체계를 갖추었다. 이와 같은 과제를 통하여 우리나라 고유의 팽이버섯에 대한 유전체 완전해독과 우리고유의 원천기술을 확보할 수 있을 것이다. 또한 유전체 해독정보를 이용하여 신기능성 유용유전자를 다량 발굴하고, 유전자 기능분석으로 지적소유권을 조기에 확보할 수 있을 것으로 기대된다. 팽이버섯의 대량 유전자 분리 및 기능분석 기술 확립으로 유용유전자 발굴 시스템을 구축함으로써 새로운 분자육종 소재를 발굴하여 제공하고, 팽이버섯 형질전환기술의 확립으로 Post-genome 연구 tool로 활용할 수 있을 뿐 아니라 팽이버섯 유전체 해독정보를 기반으로 한 약리작용 및 발현·대사관련 유전자 기능분석으로 고부가성 생물소재를 개발할 수 있을 것으로 기대된다.

  이 논문의 공급업체의 불확실성하에서의 신문팔이 문제를 다루고 있다. 즉 공급업체의 공급량이 소매업체가 주문한 양을 충족하기 못하는 상황을 고려한 것이다. 여기서 우리는 기대 이익을 최대화하는 최적의 주문량을 구하였고, 기존의 연구와 달리 소매업체의 위험 성향을 고려하기 위해 하향 리스크에 대한 제약 조건을 추가하여, 위험 성향이 높을수록 더 많은 주문량을 사용한다는 결과를 사례 연구를 통해 확인할 수 있었다.

High temperature dielectric constants of the various ceramic materials have been measured using cavity perturbation method. The measurements were applied to refractory, traditional and fine ceramic powder compacts from room temperature to . Calibration constant in the equation suggested by Hutcheon et al., was determined from the dielectric constants of reference specimen (teflon and alumina) at room temperature. From these results, informations on the refectory materials were obtained for the microwave kiln design and understanding of the microwave heating effects of ceramics have been improved.

In this paper, we implement a portable bioelectric signal measurement system for the safety of industrial workers. The developed system consists of two parts: the one is boielectric signal measurement unit and the other is signal analyzer system with PDA. The former includes signal processing part, A/D convertor, and 8051 based microprocessor, the latter includes software for signal analysis and display. The developed system detects industrial worker's ECG and displays and stores it to PDA. The ECG data in PDA can be transmitted to PC located in a distance, allowing a doctor to review the ECG and make a treatment decision. A doctor analyzes the ECG data and gives medical treatment to industrial worker.

This study was conducted to find out the effect of follicle size and oocyte type on in vitro maturation of poricine follicular oocytes. TCM-HEPEAS medium was used to basic medium, and the oocyte matured in vitro was stained with the Rapid staining method. The results obtained were summarized as follows; 1. The number of follicles an ovary was 20.5. The number of A-and B-typed oocytes an ovary was 2.34. The proportion of A-and b-types oocytes was 40% of the recovery oocytes. 2. Cumulus expanison indexes(CEI) by the follicle size were 1.62∼2.34(<2mm), 1.27∼2.28(2∼5mm) and 1.46∼2.75(>5mm). It was no differ to maturation rate by the follicle size. 3. The degree of oocyte maturation based on oocyte type did not differ for B-and C-typed oocyted but the index of oocyte type A was higher than that of b-and C-typed oocytes. 4. When follicluar oocytes were cultured for 42 hours, the proportion of the Met-II(second metaphase) stage were 22.5% (degree 1), 35.4%(degree 2) and 65.5% (degree 3).

김치는 용기에 담아 보관하면서 위에서부터 꺼내 먹고 있어서 실제 김치 맛은 표층김치 맛과 직결된다. 따라서 표층부 김치의 변질을 최소화 할 수 있는 효과적인 방법을 모색하기 위하여 표면마감을 4가지 방법 즉 김치표층에 재래식 누름돌을 놓아 저장한 경우(A), 김치를 PE백에 넣어 봉한 후 표본병에 담아서 저장한 경우(B), 누름돌을 PE-film으로 싼 누름돌을 사용한 경우(C)와 그리고 김치를 표본병에 담고 그 위에 우거지(약 4cm)로 표면을 덮어 마감(D)한 후 각각을 10±5℃에서 60일 동안 저장하면서 표층김치(2~5cm)의 pH값, 금속이온함량, 산막효모의 발생유무, 김치국물의 적색도, 신선미와 씹힘성에 대한 관능검사 및 경도를 조사 비교하였다. 김치국물의 pH값은 저장 직전에 약 6.0이었는데 A, C, D는 저장기간 중 낮아졌다가 높아진 반면 B는 좋은 김치의 최적 pH인 4.0~4.2가 유지되었다. 재래식 누름돌 사용(A)은 Fe함량을 크게 증가(6배 이상)시켰으며, Mn과 Cu가 검출되었다. 김치표면에서의 산막효모는 B를 제외하고 A, C, D 모두에서 번식되었고, 적색도도 B의 경우만 전 저장기간 동안 선명한 적색이 유지되었으며 A 경우는 진한 흑색을, C와 D의 경우는 낮은 적색도를 나타냈다. 기계적 경도 역시 B의 경우를 제외하고는 모두가 심히 감소하였고 신선미와 씹힘성에 대한 관능평가에서도 B의 경우와 A와 C 및 D의 표면마감 방법보다 훨씬 우수(p〈0.01)하게 평가되었다.