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991.
In the electronic packaging field, the Sn-Zn alloy system has been recommended as a high-temperature Pb-free solder. There
is a need for thermodynamic data on the Sn-Ni-Zn ternary system. Such data would serve as a basis for understanding the interfacial
reaction between Sn-Zn high-temperature solder and Ni substrates and for thermodynamically evaluating the proper composition
level of Ni and Zn in Sn-based solder. This study has investigated the phase equilibria of the Sn-Ni-Zn ternary system at
800°C, 500°C, and 200°C (for Ni composition of less than 60 at.%). Scanning electron microscopy (SEM), x-ray diffraction (XRD),
and electron probe microanalysis (EPMA) were used to identify the equilibrium phases. On the basis of the experimental data
and thermodynamic parameters, the isothermal sections of the Sn-Ni-Zn ternary system have been described, considering the
ternary solubility in the binary phases and newfound ternary phases τ1 (Sn3Ni4Zn3) and τ2 (Sn4Ni4Zn2). 相似文献
992.
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
993.
994.
995.
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
996.
Vo-Gia Loc Se-goh Roh Ig Mo Koo Duc Trong Tran Ho Moon Kim Hyungpil Moon Hyouk Ryeol Choi 《Robotics and Autonomous Systems》2010,58(5):666-675
In this paper, a general study on improving adaptability of quadruped walking and climbing robot in complex environment is presented. First, a sensing system composed of range and gyroscope sensors in a novel arrangement is developed. By combining the sensing signals and the internal state of the robot, the surface geometry of the environment is sufficiently reconstructed in real-time. Secondly, a planning algorithm for the robot to overcome the reconstructed environment is conducted. Based on the reshaped surface, the planning algorithm not only provides the exact body trajectory and foot positions but also the adaptability of the robot in a specific environment. A method to improve the adaptability of the walking and climbing robot is also introduced. Thanks to the adherent ability of the robot, the center of gravity of the robot is allowed to move outside the support polygon to increase the reach-ability of the next swing leg. Finally, the effectiveness of the proposed approach is verified by the performances of the experiments in complex environments using a quadruped walking and climbing robot named MRWALLSPECT IV. 相似文献
997.
Cabbage (Brassica oleracea var. capitata L.) enriched with selenium through foliar spraying was used to study the effect of drying process on its selenium retention and other quality criteria. Parameters such as blanching, seasoning, temperature, pH, and time of treatment were studied and evaluated to obtain an optimal processing condition for dehydrated selenium-enriched cabbage. After blanching, the barrier for mass and heat transfer of cabbage cellular materials became lower so that the heat damage was high. Blanching parameters set at 95°C and 60 s retained selenium and vitamin C in cabbage best as well as inactivated enzymes present in cabbage. Seasoning reduced the water activity of cabbage and subsequently reduced the loss of selenium. Blanching and seasoning could prevent browning deterioration of cabbage and reasonably kept the fresh color. The selenium loss kinetics during drying obeyed the first-order reaction and its activation energy was 44.0 kJ mol?1. 相似文献
998.
To find a novel high-performance anode material for lithium-ion batteries, a new form of carbon characterized by highly crimped and crystalline nanofibrillar microtextures was produced by heat treating polyacrylonitrile/FeCl3 hybrid precursor and subsequent thermal annealing under hydrogen gas. This form of carbon exhibits a rechargeable capacity of ∼630 mAh/g, which is superior to that of graphite, with a Coulomb efficiency of ∼70%. Further, the new form of carbon was found to exhibit an efficiency of lithium ion insertion/extraction of ∼100% in the voltage range from 0.06 to 0.80 V, with a capacity of ∼400 mAh/g. We speculate that this excellent capacity is due to the characteristic structure of this form of carbon, i.e. its highly entangled web-like hyperstructure consisting of highly crimped and crystalline nanofibrillar microtextures, which enables good permeation and has high resilience to volume deformation during the insertion/extraction of Li ions. 相似文献
999.
1000.
Sung Hwan Hwang Mu Hee Cho Sae-Kyoung Kang Han Seo Cho Tae-Woo Lee Hyo-Hoon Park 《Lightwave Technology, Journal of》2008,26(11):1479-1485
An architecture of a passively assembled optical platform is suggested for a chip-to-chip optical interconnection system. The platform is constructed using all-fiber media for the optical paths: a fiber-embedded optical printed-circuit board (OPCB) and 90-bent fiber connector. The passive assembling was achieved by employing the guide pins/holes of commercialized ferrules in the optical link between the OPCB, 90-bent fiber connector, and the transmitter/receiver (Tx/Rx) module. From this interconnection scheme, a low total optical loss of was obtained. From an assembled platform with 10 Gb/s/ch 4 ch Tx/Rx modules, a 7-Gb/s/ch data transmission was demonstrated with a bit error rate below , involving the optical and electrical crosstalk arisen in the whole channel operation. 相似文献