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991.
992.
Sn-Fe/carbon nanocomposites were synthesized by the mechanochemical treatment of Sn with various amounts of an Fe/C composite through the pyrolysis of Fe(III) acetylacetonate. The composites were then evaluated as alternative anode materials for rechargeable lithium batteries. Based on the obtained ex situ X-ray diffraction (XRD) data, X-ray absorption spectroscopy (XAS) results, and differential capacity plots (DCPs), a reaction mechanism was suggested. It was found that increasing the amounts of the SnFe phase and pyrolyzed carbon in the composite improved its electrochemical characteristics in terms of its capacity retention. 相似文献
993.
Wireless mesh networks facilitate the development of the many group oriented applications by extending the coverage area of
the group communication. Group communication in a wireless mesh network is complicated due to dynamic intermediate mesh points,
access control for communications between different administrative domains, and the absence of a centralized network controller.
In this study, we propose a topology-matching decentralized multi-service group key management scheme for wireless mesh networks.
It allows service providers to update and deliver their group keys to valid members in a distributed manner using the identity-based
encryption scheme. The analysis result indicates that the proposed scheme has advantages with regard to the rekeying cost
and storage overhead for a member and a mesh point in multi-sender group communication environments. The stateless property
is also achieved such that a stateless member, who could not be constantly online, can easily decrypt the rekeying messages
without recording the past history of transmission. 相似文献
994.
The Monte Carlo Potts model with n-fold method was used to simulate grain structure evolution in thin Cu films according to energetic competition principles.
Surface/interface, grain boundary, and strain energy factors were applied to determine grain growth and crystallographic texture
evolution as a function of film thickness. Furthermore, annealing twins were simulated through specific criteria that arbitrarily
insert twin grains into the structure through grain boundary energy considerations. Four different types of microstructures
were observed experimentally and simulated by the Monte Carlo technique. 相似文献
995.
Myung‐Han Hyun Sung‐Yeol Kim Yun‐Suk Kang Yo‐Sung Ho 《International journal of imaging systems and technology》2010,20(3):285-293
Digital matting for extracting foreground objects from an image is an important process to generate special effects in the movie industry and the broadcasting center. Recently, a digital matting algorithm has been developed to create an alpha matte using a well‐focused image generated from multiview images. However, this method could generate only a single‐view alpha matte, even though it used multiple cameras. In this article, we propose a new estimation scheme for multiview alpha mattes by sharing the trimap of the reference view. Furthermore, we use the motion vector to update the trimap for video matting. After we extract foreground objects from all view images, we composite the foreground objects with the corresponding background images captured in the same multiview camera arrangement. Experimental results demonstrate that multiview composite images can generate reasonably natural 3D views through the stereoscopic monitor. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 285‐293, 2010 相似文献
996.
997.
Seung Won Ji No Sung Myung Tong Seop Kim 《Journal of Mechanical Science and Technology》2011,25(4):945-955
Balance-of-plant components, especially the air supply system, have a critical impact on the operating condition, performance,
and reliability of polymer electrolyte fuel cells (PEMFCs). Thus, we investigated the performance and operating characteristics
of a coupled system integrating a PEMFC and an air supply unit. The performance characteristics of the fuel cell stack were
modeled using a semi-experimental correlation, and the operating characteristics of a shell-and-tube type membrane humidifier
was modeled using heat and mass transfer principles. The models of both components were validated. A turbo-blower determined
the condition of the air supplied to the humidifier and its characteristics were modeled using a performance map. A program
was developed to simulate the operation of a PEMFC system consisting of the fuel cell stack and the air supply unit, and its
operating characteristics at various conditions were investigated. In particular, the effects of operating conditions (ambient
temperature and load) on the performance of both the humidifier and the fuel cell stack were examined, and the variations
of critical operating parameters were analyzed. 相似文献
998.
To analyze the withdrawal force curve in the wetting balance curve, wetting balance tests using the 63Sn-37Pb and 96.5Sn-3.6Ag
eutectic solders were conducted by varying the immersion speed, sample perimeter, and solder temperature. The mechanism of
the withdrawal force curve was reviewed and a new method for calculating the surface tension of solders using the withdrawal
force curve was introduced. The results showed that the maximum point of the withdrawal force curve is generated when the
sliding solder meets the bottom corners of a sample and the contact angle is reduced to zero. The maximum withdrawal force
subtracted by end force can be expressed using force balance equation as F=pγ. Therefore, the surface tension of the solder
can be calculated by dividing the maximum withdrawal force by the sample parameter. 相似文献
999.
Hun‐Sik Kim Byung Hyun Park Jin‐San Yoon Hyoung‐Joon Jin 《Polymer International》2007,56(8):1035-1039
Biodegradable composites consisting of aliphatic polyesters (poly[(butylenes succinate)‐co‐(butylenes adipate)] (PBSA)) and Bombyx mori silk fibers coated with carbon nanotubes (CNTs) were prepared by melt compression molding. The mechanical properties of PBSA were enhanced by the incorporation of a small amount (3 wt%) of CNT‐coated silk fibers, while allowing its potential biodegradability to be retained, which could make these composites good candidates for commodity materials such as general‐purpose plastics. This improvement is attributed to the interactions between PBSA and CNT‐coated silk fibers in the composites. The average interfacial shear strength of the composites consisting of CNT‐coated silk fibers and PBSA matrix was 1.7 MPa, as measured by the microbond droplet test, while that of composites consisting of pure silk fibers and PBSA was only 1.1 MPa. The morphology of the CNT‐coated silk fiber‐reinforced composites was observed using scanning electron microscopy. Copyright © 2007 Society of Chemical Industry 相似文献
1000.
Jong-Jin Choi Joo-Hee Lee Dong-Soo Park Byung-Dong Hahn Woon-Ha Yoon Hua-Tay Lin 《Journal of the American Ceramic Society》2007,90(6):1926-1929
Conductive La0.8 Sr0.2 MnO3 (LSM) and La0.6 Sr0.4 Co0.2 Fe0.8 O3 (LSCF) layers with a thickness of ∼10 μm were deposited on ferritic stainless steel (SS) by the aerosol deposition method, for use as an oxidation resistance-coating layer in the metallic interconnector of a solid oxide fuel cell. The coated layers were fairly dense without pores or cracks, and maintained good adhesion even after oxidation at 800°C for 100 h. The surface of the bare SS after annealing at 800°C for 100 h was covered with Cr2 O3 and Fe3 O4 oxide scales, and the electrical conductivity was sharply decreased. However, the LSM- and LSCF-coated SSs showed a surface microstructure with almost no oxidation and maintained good electrical conductivity after annealing at 800°C for 100 h. The area-specific resistance (ASR) of LSM- and LSCF-coated alloys after 100 h of oxidation at 800°C was 20.6 and 11.7 mΩ·cm2 , respectively. 相似文献