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21.
Wonbaek Kim Na-Ri Kim In-Yong Ko Sung-Wook Cho Je-Shin Park In-Jin Shon 《Metals and Materials International》2011,17(2):239-243
Highly dense nanostructured TiNi with a relative density of up to 99 % was obtained within two minutes by pulsed current activated
sintering under a pressure of 80 MPa. The advantage of this process is that it allows very quick densification to near theoretical
density and prohibits grain growth in nano-structured materials. The microstructural and mechanical properties of the dense
TiNi produced by PCAS were investigated. 相似文献
22.
In-Jin Shon Dong-Mok LeeJung-Mann Doh Jin-Kook YoonIn-Yong Ko 《Materials Science and Engineering: A》2011,528(3):1212-1215
A dense nanostructured MoSi2-SiC-Si3N4 composite was sintered by the high frequency induction heating method within 2 min from mechanically activated powder of Mo2N, Mo2C and Si. Highly dense MoSi2-SiC-Si3N4 composite was produced under simultaneous application of a 80 MPa pressure and the induced current. Mechanical properties and grain size of the composite were investigated. The average hardness and fracture toughness values obtained were 1420 kg/mm2 and 4.5 MPa m1/2, respectively. 相似文献
23.
Taeshik Shon Jaeik Cho Kyusunk Han Hyohyun Choi 《Mobile Networks and Applications》2014,19(3):404-413
Cloud computing is the coming new era of information processing and has proved its benefits in high scalability and functional diversity. However, almost all cloud-computing architectures including SaaS, PaaS, and IaaS are vulnerable to serious security issues. Similarly, Mobile Cloud Computing (MCC) is vital to overcoming mobile limited storage and computing capabilities. MCC authentication and authorization issues must be provided on two levels: login password control and the environment from where the cloud is accessed. MCC has overcome the barrier of limited storage by providing remote storage but requires a strict security system that is responsible for retrievability, integrity, and seamless storage access. Elasticity and connectivity are also of major concern in MCC because delays and jitters cause degradation in the user experience. Cloud-computing architecture creates more challenges in maintaining security because of the liberty of users to choose any MCC architecture. Thus in this paper we discuss current cloud computing issues and future directions. 相似文献
24.
25.
I. J. Shon Z. A. Munir K. Yamazaki K. Shoda 《Journal of the American Ceramic Society》1996,79(7):1875-1880
A method to simultaneously synthesize and consolidate MoSi2 from powders of Mo and Si was investigated. Combustion synthesis was carried out under the combined effect of an electric field and mechanical pressure. Highly dense molybdenum silicide up to (99.2%) was produced from elemental powders in one step. Minor amounts of Mo5 Si3 were present at the boundaries of MoSi2 grains in the interior of samples made from stoichiometric reactants. The addition of 2.5 mol% Si excess, however, resulted in Mo5 Si3 -free, dense MoSi2 products. 相似文献
26.
Dense nanophase 8 mol% yttria-stabilized zirconia was sintered by high-frequency induction heated sintering (HFIHS) within 6 min from 8YSZ nanopowder prepared by co-precipitation method. Sintering was accomplished under the combined effects of an induced current and mechanical pressure. Highly dense 8YSZ with relative density of up to 96% was produced under simultaneous application of a 60-MPa pressure and the induced current. The effects of Fe2O3 additions on the sintering behavior, mechanical properties and ionic conductivities of the 8YSZ were investigated. 相似文献
27.
Jin-Seong Kim Ngoc-Huan Nguyen Myung-Eun Song Jong-Bong Lim Dong-Soo Paik Sahn Nahm Jong-Hoo Paik Byung-Hyun Choi Soon-Jae Yu 《International Journal of Applied Ceramic Technology》2009,6(5):581-586
Bi2 O3 was added to a nominal composition of Zn1.8 SiO3.8 (ZS) ceramics to decrease their sintering temperature. When the Bi2 O3 content was <8.0 mol%, a porous microstructure with Bi4 (SiO4 )3 and SiO2 second phases was developed in the specimen sintered at 885°C. However, when the Bi2 O3 content exceeded 8.0 mol%, a liquid phase, which formed during sintering at temperatures below 900°C, assisted the densification of the ZS ceramics. Good microwave dielectric properties of Q × f =12,600 GHz, ɛr =7.6, and τf =−22 ppm/°C were obtained from the specimen with 8.0 mol% Bi2 O3 sintered at 885°C for 2 h. 相似文献
28.
Jinhan Shon Ji-Hyun Eo Su Jung Hwang Jong-Bang Eun 《Food science and biotechnology》2011,20(1):99-106
Optimum conditions for collagen extraction from skate (Raja kenojei) skins with various liming concentrations, extraction solution pH, extraction temperature and time, and functional properties
were investigated. The optimum conditions for collagen extraction are as combination of place the skins in a lime solution
of 0.15 N of NaOH, extract with 5 volumes water (pH 4.0) for 4 hr at 40°C, filter, centrifuge, and lyophilize to obtain collagen
powder. The characteristics of skate skin collagen obtained under optimum extraction conditions were: solubility 82.7%, turbidity
0.28, and Hunter color L, a, and b values were 88.4, 0.92, and 11.2, respectively. On the other hand, the acidic pH values (3.0 and 5.0) of collagen were more
resistant to precipitation upon extended heating. 相似文献
29.
Synthesis of dense MoSi2 by high-frequency induction heated combustion and its mechanical properties
Kim Hwan Cheol Park Choong Do Jeong Jeong Wung Shon In Jin 《Metals and Materials International》2003,9(2):173-178
Dense MoSi2 compound was synthesized with the high-frequency induction heated combustion synthesis method in one step from elemental
powders of Mo and Si within 2 min. Simultaneous combustion synthesis and densification were carried out under the combined
effects of induced current and mechanical pressure. A highly dense MoSi2 with a relative density of up to 98% was produced with simultaneous application of 60 MPa pressure and induced current. The
percentages of the total shrinkage occurring before and during the synthesis reaction were 16% and 53%, respectively. The
average grain size was about 15 μm and a slight amount of Mo5Si3 was observed at the boundaries of the MoSi2 grains. The fracture toughness and hardness values obtained were 3.5 MPa·m1/2 and 1050 kg/mm2, respectively. These values were similar to those of commercial ones. 相似文献
30.
Soobok Shin Taeshik Shon Hongjin Yeh Kangseok Kim 《Peer-to-Peer Networking and Applications》2014,7(4):612-619
With the advent of new generation of mobile access devices such as smartphone and tablet PC, there is coming a need for ubiquitous collaboration which allows people to access information systems with their disparate access devices and to communicate with others in anytime and in anywhere. As the number of collaborators with a large number of disparate access devices increases in ubiquitous collaboration environment, the difficulties for protecting secured resources from unauthorized users as well as unsecured access devices will increase since the resources can be compromised by inadequately secured human and devices. Therfore, authentication mechanism for access of legitimate participants is essential in ubiquitous collaboration environment. In this paper we present an efficient authentication mechanism in ubiquitous collaboration environment. We show that proposed scheme is secure through security analysis and is efficient through the experimental results obtained from the practical evaluation of the scheme in ubiquitous collaboration environment. 相似文献