The Experts below are selected from a list of 129117 Experts worldwide ranked by ideXlab platform
He Wang - One of the best experts on this subject based on the ideXlab platform.
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Experimental verification of upgraded metallurgical silicon photovoltaic power plant
Clean Technologies and Environmental Policy, 2014Co-Authors: Hong Yang, Haidong Wang, He Wang, Ding JiyeAbstract:The upgraded metallurgical silicon (UMG-Si) purified by a metallurgical Process Route directly is more energy efficient than the conventional Siemens Process, but high metallic impurities are the cause of a large fraction of the total recombination events in solar cells made from UMG-Si. The efficiency of crystalline silicon solar cells made by such materials is lower than that from a chemical Route, and UMG solar cells have big light-induced degradation. So, there always exist debates about using the upgraded metallurgical silicon for photovoltaic. In this paper, the impurity contents of silicon samples obtained in different stages were investigated, and a four-year verification of the largest UMG photovoltaic power plant in the world was conducted for the first time. The reliability, operating performance, and defects of UMG photovoltaic power plant were analyzed.
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The materials characteristic and the efficiency degradation of solar cells from solar grade silicon from a metallurgical Process Route
Journal of Materials Science, 2010Co-Authors: Hong Yang, He WangAbstract:The rising conventional energy prices have opened up the market for photovoltaic, but the lack of polycrystalline silicon from the chemical Route restricts the growth of crystalline silicon solar cells. Recently there is a trend that produces solar cells by using the newly developed solar grade silicon feedstock from a metallurgical Process Route. In this article, the chemical components of solar grade silicon feedstock are analyzed. The single crystalline silicon solar cells from 100% solar grade silicon feedstock from a metallurgical Process Route are investigated. The outdoor performance of solar modules encapsulated by such cells is reported. The experimental evidence suggests that such solar cells can achieve the average efficiency higher than 14% on single crystalline silicon wafers. However, the efficiency degradation of solar cells under natural sunlight is significant, and the electrical uniformity of small cells diced from the whole cell is too bad. The metal impurities, oxygen, carbon, and their complexes influence the performance stabilization. The article proves that the module made by such cells has a big cell mismatch loss than normal cells made by electronic grade silicon, even if these cells come from the same sort. And the operating temperature of the cells of the modules is 15–22 °C higher than normal modules under the same conditions. The solar grade silicon feedstock from a metallurgical Process Route has to be improved farther in order to be used in photovoltaic industry.
Jeffrey R Alcock - One of the best experts on this subject based on the ideXlab platform.
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creating movable interfaces by micro powder injection moulding
Journal of Materials Processing Technology, 2014Co-Authors: Usama M Attia, M Hauata, I Walton, Daniele Annicchiarico, Jeffrey R AlcockAbstract:Abstract This paper presents a novel in situ technique to produce articulated components with high-precision, micro-scale movable interfaces by micro-powder injection moulding (μPIM). The presented Process Route is based on the use of micro-scale sacrificial layer between the movable subcomponents which is eliminated during the debinding step, creating a dimensionally-controlled, micro-scale mobile interface. The fabrication technique combines the advantages of micro-powder overmoulding, catalytic debinding and sintering. The demonstrated example was a finger bone prosthesis joint consisting of two sub-components with an interface between components of 200 μm in size. The geometries of the sub-components were designed such that they are inseparable throughout the Process whilst allowing them to move relative to each other after the debinding stage. The components produced showed the feasibility of the Process Route to produce readily-assembled meso-, and potentially micro-, scale articulated systems.
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fabrication of ceramic micro scale hollow components by micro powder injection moulding
Journal of The European Ceramic Society, 2012Co-Authors: Usama M Attia, Jeffrey R AlcockAbstract:Rapid developments in microsystem technologies demand ceramic microcomponents of increasing geometrical complexity. State-of-the-art microfabrication Routes of ceramics are either limited in geometrical complexity and/or high volume capabilities. This paper presents a Process Route by which ceramic microcomponents with relatively complex three-dimensional architectures could be realised by a high-volume technique. The proposed strategy, in which yttria-stabilised zirconia was implemented, combines the capabilities of insert-micromoulding, powder micro-overmoulding, catalytic debinding and sintering. The produced architectures demonstrate the capability of the technique to combine the high performance of ceramic materials with the dimensional accuracy and mass manufacturability of powder micromoulding.
Hong Yang - One of the best experts on this subject based on the ideXlab platform.
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Experimental verification of upgraded metallurgical silicon photovoltaic power plant
Clean Technologies and Environmental Policy, 2014Co-Authors: Hong Yang, Haidong Wang, He Wang, Ding JiyeAbstract:The upgraded metallurgical silicon (UMG-Si) purified by a metallurgical Process Route directly is more energy efficient than the conventional Siemens Process, but high metallic impurities are the cause of a large fraction of the total recombination events in solar cells made from UMG-Si. The efficiency of crystalline silicon solar cells made by such materials is lower than that from a chemical Route, and UMG solar cells have big light-induced degradation. So, there always exist debates about using the upgraded metallurgical silicon for photovoltaic. In this paper, the impurity contents of silicon samples obtained in different stages were investigated, and a four-year verification of the largest UMG photovoltaic power plant in the world was conducted for the first time. The reliability, operating performance, and defects of UMG photovoltaic power plant were analyzed.
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The materials characteristic and the efficiency degradation of solar cells from solar grade silicon from a metallurgical Process Route
Journal of Materials Science, 2010Co-Authors: Hong Yang, He WangAbstract:The rising conventional energy prices have opened up the market for photovoltaic, but the lack of polycrystalline silicon from the chemical Route restricts the growth of crystalline silicon solar cells. Recently there is a trend that produces solar cells by using the newly developed solar grade silicon feedstock from a metallurgical Process Route. In this article, the chemical components of solar grade silicon feedstock are analyzed. The single crystalline silicon solar cells from 100% solar grade silicon feedstock from a metallurgical Process Route are investigated. The outdoor performance of solar modules encapsulated by such cells is reported. The experimental evidence suggests that such solar cells can achieve the average efficiency higher than 14% on single crystalline silicon wafers. However, the efficiency degradation of solar cells under natural sunlight is significant, and the electrical uniformity of small cells diced from the whole cell is too bad. The metal impurities, oxygen, carbon, and their complexes influence the performance stabilization. The article proves that the module made by such cells has a big cell mismatch loss than normal cells made by electronic grade silicon, even if these cells come from the same sort. And the operating temperature of the cells of the modules is 15–22 °C higher than normal modules under the same conditions. The solar grade silicon feedstock from a metallurgical Process Route has to be improved farther in order to be used in photovoltaic industry.
Usama M Attia - One of the best experts on this subject based on the ideXlab platform.
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creating movable interfaces by micro powder injection moulding
Journal of Materials Processing Technology, 2014Co-Authors: Usama M Attia, M Hauata, I Walton, Daniele Annicchiarico, Jeffrey R AlcockAbstract:Abstract This paper presents a novel in situ technique to produce articulated components with high-precision, micro-scale movable interfaces by micro-powder injection moulding (μPIM). The presented Process Route is based on the use of micro-scale sacrificial layer between the movable subcomponents which is eliminated during the debinding step, creating a dimensionally-controlled, micro-scale mobile interface. The fabrication technique combines the advantages of micro-powder overmoulding, catalytic debinding and sintering. The demonstrated example was a finger bone prosthesis joint consisting of two sub-components with an interface between components of 200 μm in size. The geometries of the sub-components were designed such that they are inseparable throughout the Process whilst allowing them to move relative to each other after the debinding stage. The components produced showed the feasibility of the Process Route to produce readily-assembled meso-, and potentially micro-, scale articulated systems.
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fabrication of ceramic micro scale hollow components by micro powder injection moulding
Journal of The European Ceramic Society, 2012Co-Authors: Usama M Attia, Jeffrey R AlcockAbstract:Rapid developments in microsystem technologies demand ceramic microcomponents of increasing geometrical complexity. State-of-the-art microfabrication Routes of ceramics are either limited in geometrical complexity and/or high volume capabilities. This paper presents a Process Route by which ceramic microcomponents with relatively complex three-dimensional architectures could be realised by a high-volume technique. The proposed strategy, in which yttria-stabilised zirconia was implemented, combines the capabilities of insert-micromoulding, powder micro-overmoulding, catalytic debinding and sintering. The produced architectures demonstrate the capability of the technique to combine the high performance of ceramic materials with the dimensional accuracy and mass manufacturability of powder micromoulding.
Nobuhiro Yoshikawa - One of the best experts on this subject based on the ideXlab platform.
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friction powder compaction Process for fabricating open celled cu foam by sintering dissolution Process Route using nacl space holder
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2013Co-Authors: Yoshihiko Hangai, Kousuke Zushida, Rintaro Ueji, Osamu Kuwazuru, Hidetoshi Fujii, Nobuhiro YoshikawaAbstract:Abstract Open-celled metal foams have received considerable attention in various fields and are expected to be used as engineering materials where heat exchange, sound absorption and filtration are required. In this study, Cu foam specimens with NaCl volume fractions of 60%, 70% and 80% were successfully fabricated by the friction powder compaction (FPC) Process with the sintering and dissolution Process (SDP) using NaCl as space holders. In the FPC Process, no external heat source was used for fabricating Cu foam except for the friction heat generated by the rotating tool plunged into the die and powders. From the X-ray CT and SEM observation of the pore structures of the fabricated Cu foam, it was found that almost the entire specimen had a pore structure similar to the NaCl morphology, regardless of the NaCl volume fraction. This is mainly because the sintering Process for Cu particles in the FPC Process was achieved at a temperature lower than the melting point of NaCl. From compression tests of the fabricated Cu foam, Cu foam exhibited ductile fracture regardless of its NaCl volume fraction, which is considered to be attributed to the good bonding between Cu particles. The plateau stress and energy absorption decreased with increasing NaCl volume fraction, indicating strong relationships between them. The Cu foam with the highest energy absorption per unit volume up to the specific stress changed from the high-NaCl-volume-fraction Cu foam to the low-NaCl-volume-fraction Cu foam with increasing compression stress. Consequently, it was shown that the mechanical properties of Cu foam can be controlled by adjusting the volume fraction of NaCl.
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Friction Powder Compaction for Fabrication of Open-Cell Aluminum Foam by the Sintering and Dissolution Process Route
Metallurgical and Materials Transactions A, 2012Co-Authors: Yoshihiko Hangai, Hiroaki Yoshida, Nobuhiro YoshikawaAbstract:A new friction powder compaction (FPC) Process by the sintering and dissolution Process (SDP) Route for fabricating open-cell aluminum (Al) foam, which requires no external heat sources, was developed. Foams with porosities of 74 and 83 pct were successfully fabricated and their compressive responses were investigated. The sintered mixture during the removal Process was observed nondestructively by X-ray computed tomography (CT) to reveal the progress of the removal of soluble particles and to confirm that they were completely dissolved.