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91.
Bongsoo Kim Seungbum Hong Hyunwoo Choi Won‐Hee Ryu Haemin Paik Yoon‐Young Choi Hyuk‐Sang Kwon Kwangsoo No 《Journal of the American Ceramic Society》2013,96(5):1355-1358
Nanoscale ferroelectric honeycombs, comprised of vertically aligned PbTiO3 nanotubes, are fabricated by vapor phase reaction between lead acetate‐infiltrated TiO2 nanotubes and PbO vapor. PbTiO3 nanohoneycombs converted by vapor phase reaction at 550°C showed well‐aligned nanoscale structure with alignment angle less than 1° and well‐defined ferroelectric properties with the effective piezoelectric coefficient of 44 pm/V. This novel nanoscale structure is expected to facilitate high efficiency sensing of electromechanical and electrochemical stimuli. 相似文献
92.
Eun-Hee Kim Je-Hyun Lee Yeon-Gil Jung Jung-Chel Jang Ungyu Paik 《Ceramics International》2013,39(4):3993-3998
An additive reagent was introduced into a water glass binder system for enhancing the mechanical properties and dimension stability of a casting mold, and for improving the surface quality of a cast product. Two different processes with three different additive reagents were employed to investigate the relation between fracture strength of the mold and water (H2O) existed in the mold. In processes I and II, the mold samples were coated with a water glass binder, and then dipped into different solutions with additive reagent after and before carbon dioxide (CO2) hardening, respectively. The fracture strength of the mold was enhanced by reducing H2O content in the mold, achieved by a hydrolysis reaction of additive reagents. In process I, the H2O movement was restricted in the mold by the solid phase, converted from the water glass during CO2 hardening. When employing process II, especially in the TEOS used as additive reagent, the fracture strength was significantly increased due to the effective reduction of H2O content in the mold and the homogeneous generation of glass phase by a sol–gel reaction of the additives. 相似文献
93.
Young‐Min Kim Hyun‐Dong Paik Dong‐Sun Lee 《Journal of the science of food and agriculture》2002,82(9):998-1002
Fresh oysters and ground beef were wrapped in antimicrobial films coated with a bacteriocin (nisin or lacticin NK24) incorporated into a polyamide binder layer. The packaged foods were stored at 3 and 10 °C and changes in counts of total aerobic bacteria and coliform bacteria were monitored together with appropriate quality attributes in order to determine the influence of the bacteriocin‐coated films on quality preservation and shelf‐life extension. Compared to plain low‐density polyethylene film, plastic films with incorporated bacteriocins slowed down microbial growth on packaged oysters and ground beef at both temperatures, contributed in some degree to the preservation of chemical quality and extended shelf‐life significantly. The effects of the antimicrobial films on the suppression of coliform bacterial growth were more pronounced at 10 than at 3 °C , while the effects on total aerobic bacteria were consistently evident at both temperatures. There was no difference in food quality preservation between the two types of antimicrobial film. © 2002 Society of Chemical Industry 相似文献
94.
Mi-Ri Joung Jin-Seong Kim Myung-Eun Song Sahn Nahm Jong-Hoo Paik Byung-Hyun Choi 《Journal of the American Ceramic Society》2009,92(7):1621-1624
The formation process and microwave dielectric properties of the Mg2 V2 O7 ceramics were investigated. The MgV2 O6 phase that was formed at around 450°C interacted with remnant MgO above 590°C to form a homogeneous monoclinic Mg2 V2 O7 phase. Finally, this monoclinic Mg2 V2 O7 phase was changed to a triclinic Mg2 V2 O7 phase for the specimen fired at 800°C. Sintering at 950°C for more than 5 h produced high-density triclinic Mg2 V2 O7 ceramics. In particular, the Mg2 V2 O7 ceramics sintered at 950°C for 10 h exhibited the good microwave dielectric properties of ɛr =10.5, Q × f =58 275 GHz, and τf =−26.9 ppm/°C. 相似文献
95.
Synthesis of BaCu(B2 O5 ) Ceramics and their Effect on the Sintering Temperature and Microwave Dielectric Properties of Ba(Zn1/3 Nb2/3 )O3 Ceramics 总被引:1,自引:0,他引:1
Min-Han Kim Jong-Bong Lim Jae-Chul Kim Sahn Nahm Jong-Hoo Paik Jong-Hee Kim Kyeong-Soon Park 《Journal of the American Ceramic Society》2006,89(10):3124-3128
BaCu(B2 O5 ) ceramics were synthesized and their microwave dielectric properties were investigated. BaCu(B2 O5 ) phase was formed at 700°C and melted above 850°C. The BaCu(B2 O5 ) ceramic sintered at 810°C had a dielectric constant (ɛr ) of 7.4, a quality factor ( Q × f ) of 50 000 GHz and a temperature coefficient of resonance frequency (τf ) of −32 ppm/°C. As the BaCu(B2 O5 ) ceramic had a low melting temperature and good microwave dielectric properties, it can be used as a low-temperature sintering aid for microwave dielectric materials for low temperature co-fired ceramic application. When BaCu(B2 O5 ) was added to the Ba(Zn1/3 Nb2/3 )O3 (BZN) ceramic, BZN ceramics were well sintered even at 850°C. BaCu(B2 O5 ) existed as a liquid phase during the sintering and assisted the densification of the BZN ceramic. Good microwave dielectric properties of Q × f =16 000 GHz, ɛr =35, and τf =22.1 ppm/°C were obtained for the BZN+6.0 mol% BaCu(B2 O5 ) ceramic sintered at 875°C for 2 h. 相似文献
96.
The effects of particle size of starting materials and amount of a BaTiO3 additive on the shrinkage behavior and elemental diffusion in Ni-based internal electrodes have been investigated in order to control the shrinkage of the internal electrode in multilayer ceramic capacitors (MLCCs). Two kinds of Ni and BaTiO3 powders were used with different particle sizes. Volume shrinkage over the range of 700–1300 °C at 150 °C intervals and linear shrinkage during sintering were measured for starting materials and composites in a reducing atmosphere. The interfaces of Ni/BaTiO3 composites with 90:10 and 70:30 volume ratios, respectively, were investigated using TEM. Composites with bimodal Ni powder show less shrinkage than those with monomodal Ni powder, showing less shrinkage in monolith Ni of bimodal particle size. The shrinkage behavior is changed during sintering with increasing amounts of BaTiO3 additives in both Ni-based composites. The particle size of the BaTiO3 additive affects the shrinkage behavior of composites, without the additional amount affecting the final shrinkage. A reaction layer of about 300 nm wide is observed at the interface between the Ni and BaTiO3 powders in composites, in which elemental Ni diffuses into the BaTiO3 without counterdiffusion. 相似文献
97.
Preservation of backseolgi by modified-atmosphere packaging (MAP) method for industrial production was evaluated with respect to shelf life and a prevalent flora was identified. Backseolgi was stored in low-density polyethylene (LDP), top-sealing package (TSP), and MAP packages. The number of microflora did not substantially change in all samples at 3°C for 30 days, but rapidly increased in LDP and TSP samples at 30°C. MAP was the most effective storage method. With DNA sequence analysis, it appeared that the predominant contaminant belonged to the genus Penicillium, and it was named Penicillium sp. DA. 相似文献
98.
W.KJ 《军民两用技术与产品》2014,(8):4-4
6月6日,中央全面深化改革领导小组第三次会议召开,会议审议通过了“关于设立知识产权法院的方案》等方案。 相似文献
99.
The present paper (Part II) is a sequel to the previous paper (Part I) [Paik JK, Seo JK. Nonlinear finite element method models for ultimate strength analysis of steel stiffened-plate structures under combined biaxial compression and lateral pressure actions—Part I: Plate elements. Thin-Walled Struct 2008, this issue, doi:10.1016/j.tws.2008.08.005.] on the application of nonlinear finite element methods for ultimate strength analysis of steel stiffened-plate structures under combined biaxial compression and lateral pressure actions. In contrast to Part I dealing with plate elements, the present paper (Part II) treats stiffened panels surrounded by strong support members such as longitudinal girders and transverse frames. In similar to Part I, some important factors of influence such as structural dimensions, initial imperfections, loading types and computational techniques in association with ultimate limit states are studied. Some useful insights in terms of nonlinear finite element method modeling are developed using ANSYS code together with the ALPS/ULSAP semi-analytical method, the latter being for the purpose of a comparison. 相似文献
100.
When used as floor joists, the new mono-symmetric LiteSteel beam (LSB) sections require web openings to provide access for inspections and various services. The LSBs consist of two rectangular hollow flanges connected by a slender web, and are subjected to lateral distortional buckling effects in the intermediate span range. Their member capacity design formulae developed to date are based on their elastic lateral buckling moments, and only limited research has been undertaken to predict the elastic lateral buckling moments of LSBs with web openings. This paper addresses this research gap by reporting the development of web opening modelling techniques based on an equivalent reduced web thickness concept and a numerical method for predicting the elastic buckling moments of LSBs with circular web openings. The proposed numerical method was based on a formulation of the total potential energy of LSBs with circular web openings. The accuracy of the proposed method's use with the aforementioned modelling techniques was verified through comparison of its results with those of finite strip and finite element analyses of various LSBs. 相似文献