The fabrication process dependent effects on single event effects (SEEs) are investigated in a commercial silicon- germanium heterojunction bipolar transistor (SiGe HBT) using three-dimensional (3D) TCAD simulat...The fabrication process dependent effects on single event effects (SEEs) are investigated in a commercial silicon- germanium heterojunction bipolar transistor (SiGe HBT) using three-dimensional (3D) TCAD simulations. The influences of device structure and doping concentration on SEEs are discussed via analysis of current transient and charge collection induced by ions strike. The results show that the SEEs representation of current transient is different from representation of the charge collection for the same process parameters. To be specific, the area of C/S junction is the key parameter that affects charge collection of SEE. Both current transient and charge collection are dependent on the doping of collector and substrate. The base doping slightly influences transient currents of base, emitter, and collector terminals. However, the SEEs of SiGe HBT are hardly affected by the doping of epitaxial base and the content of Ge.展开更多
Ionic polymer-metal composites(IPMCs)are typical smart mate-rials that are commonly used in bionic applications,including soft robots,bionic flapping aircraft,and bionic fish.However,their low output force seriously l...Ionic polymer-metal composites(IPMCs)are typical smart mate-rials that are commonly used in bionic applications,including soft robots,bionic flapping aircraft,and bionic fish.However,their low output force seriously limits device performance.Stacking of multiple IPMC actuators to improve the overall performance of soft actuators is a strategy that is used in practical applications.Under the energy dissipation condition in the IPMC stacking structure,if each single IPMC in the struc-ture has high power density,the structure will produce excel-lent performance with high efficiency that can greatly promote wider application of IPMC actuators.To meet this requirement,a method for fabrication process integration with multiple opti-mized factors was used to obtain IPMC materials in this paper.Carbon nanotube(CNT)doping,isopropyl alcohol-assisted plat-ing,and hot pressing with a mesoscopic structural mold were selected as typical optimization methods for process integration and were initially investigated separately to determine the opti-mal process parameters.By combining the best process para-meters in an integrated process,the IPMC treated by isopropyl alcohol-assisted plating and CNT doping process(No.AC7)showed excellent actuation performance and high work density(~9.71/12.36 gf,~14.93/31.89 kJ/m^(3) under 3/4 VDC).The enhanced performance meets the requirements for practical bionic applications.展开更多
Cerium dioxide, CeO2, is a potentially superior material in a myriad of areas, and many methods have been proposed to deposit single crystal CeO2 thin films. A novel fabrication technique utilizing dual plasma generat...Cerium dioxide, CeO2, is a potentially superior material in a myriad of areas, and many methods have been proposed to deposit single crystal CeO2 thin films. A novel fabrication technique utilizing dual plasma generated by metal vacuum arc (MEVVA) and radio frequency (RF) is discussed in this paper. We have recently conducted a systematic investigation to determine the optimal process window to deposit CeO2 thin films’on Si(100) substrates. The X-ray diffraction results show the existence of CeO2(100) in the as-deposited sample.展开更多
A novel liquid settling method was investigated and applied to fabricate TC4 spherical particle reinforced AZ91 alloy matrix composites.This method was called liquid state settling technique in which TC4 particles wou...A novel liquid settling method was investigated and applied to fabricate TC4 spherical particle reinforced AZ91 alloy matrix composites.This method was called liquid state settling technique in which TC4 particles would settle down under the force of gravity.High volume fraction(50%)particle reinforced AZ91 composites could be easily obtained via this novel method.This is difficult to achieve for other traditional liquid fabrication methods.In addition,there was a good dispersion of TC4 particles in the AZ91 matrix and no clusters were found,which indicate that this method was feasible.Interfacial reaction occurred and the reaction product was confirmed to be Al2Ti.Three kinds of pre-dispersion technologies were used before the settling process and different interfacial microstructures were found.Theoretical calculation and experimental results both indicated that the interfacial product which was embedded in the matrix strengthened the composites and improved the tensile strength.展开更多
We propose a co-sintering process for effective fabrication of three-layered structure for direct-write planar waveguide. Processing parameters and optical properties of the waveguide was investigated.
In textile finishing, stenters always draw considerable attention to newer inventions to boost up production via maximum utilization of energy. Prior to main drying or heat-setting chambers, intermediate heating of cy...In textile finishing, stenters always draw considerable attention to newer inventions to boost up production via maximum utilization of energy. Prior to main drying or heat-setting chambers, intermediate heating of cylindrical system especially by steam has a direct blessing to moisture evaporation, processing speed, fabric quality and so on. Based on actual operational data, this study reveals the outcomes of a pre-heating module installed within a stenter. After employing the pre-heating system to knit fabrics of different structures and compositions, 23% - 61% moisture reduction was found and the speed of processing fabrics was increased simultaneously by 17% - 30% without any compromise on fabric quality. Moreover, no less than 8.21% savings in annual electricity consumption were observed.展开更多
In recent years, flexible electronic devices have become a hot topic of scientific research. These flexible devices are the basis of flexible circuits, flexible batteries, flexible displays and electronic skins. Graph...In recent years, flexible electronic devices have become a hot topic of scientific research. These flexible devices are the basis of flexible circuits, flexible batteries, flexible displays and electronic skins. Graphene-based materials are very promising for flexible electronic devices, due to their high mobility, high elasticity, a tunable band gap, quantum electronic transport and high mechanical strength. In this article, we review the recent progress of the fabrication process and the applications of graphene-based electronic devices, including thermal acoustic devices, thermal rectifiers, graphene-based nanogenerators, pressure sensors and graphene-based light-emitting diodes. In summary, although there are still a lot of challenges needing to be solved, graphene-based materials are very promising for various flexible device applications in the future.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.61274106,11175138,and 61601352)
文摘The fabrication process dependent effects on single event effects (SEEs) are investigated in a commercial silicon- germanium heterojunction bipolar transistor (SiGe HBT) using three-dimensional (3D) TCAD simulations. The influences of device structure and doping concentration on SEEs are discussed via analysis of current transient and charge collection induced by ions strike. The results show that the SEEs representation of current transient is different from representation of the charge collection for the same process parameters. To be specific, the area of C/S junction is the key parameter that affects charge collection of SEE. Both current transient and charge collection are dependent on the doping of collector and substrate. The base doping slightly influences transient currents of base, emitter, and collector terminals. However, the SEEs of SiGe HBT are hardly affected by the doping of epitaxial base and the content of Ge.
基金This work was supported by the National Natural Science Foundation of China[11802223,61890961]Basic Research Project of China[JCKY2020110C074].
文摘Ionic polymer-metal composites(IPMCs)are typical smart mate-rials that are commonly used in bionic applications,including soft robots,bionic flapping aircraft,and bionic fish.However,their low output force seriously limits device performance.Stacking of multiple IPMC actuators to improve the overall performance of soft actuators is a strategy that is used in practical applications.Under the energy dissipation condition in the IPMC stacking structure,if each single IPMC in the struc-ture has high power density,the structure will produce excel-lent performance with high efficiency that can greatly promote wider application of IPMC actuators.To meet this requirement,a method for fabrication process integration with multiple opti-mized factors was used to obtain IPMC materials in this paper.Carbon nanotube(CNT)doping,isopropyl alcohol-assisted plat-ing,and hot pressing with a mesoscopic structural mold were selected as typical optimization methods for process integration and were initially investigated separately to determine the opti-mal process parameters.By combining the best process para-meters in an integrated process,the IPMC treated by isopropyl alcohol-assisted plating and CNT doping process(No.AC7)showed excellent actuation performance and high work density(~9.71/12.36 gf,~14.93/31.89 kJ/m^(3) under 3/4 VDC).The enhanced performance meets the requirements for practical bionic applications.
基金The work was supported by Hong Kong RGC CERG9040344 and 9040412, RGC / Germany Joint Schemes9050084 and 9050150, and CityU S
文摘Cerium dioxide, CeO2, is a potentially superior material in a myriad of areas, and many methods have been proposed to deposit single crystal CeO2 thin films. A novel fabrication technique utilizing dual plasma generated by metal vacuum arc (MEVVA) and radio frequency (RF) is discussed in this paper. We have recently conducted a systematic investigation to determine the optimal process window to deposit CeO2 thin films’on Si(100) substrates. The X-ray diffraction results show the existence of CeO2(100) in the as-deposited sample.
基金the National Natural Science Foundation of China(Grant No.51471059).
文摘A novel liquid settling method was investigated and applied to fabricate TC4 spherical particle reinforced AZ91 alloy matrix composites.This method was called liquid state settling technique in which TC4 particles would settle down under the force of gravity.High volume fraction(50%)particle reinforced AZ91 composites could be easily obtained via this novel method.This is difficult to achieve for other traditional liquid fabrication methods.In addition,there was a good dispersion of TC4 particles in the AZ91 matrix and no clusters were found,which indicate that this method was feasible.Interfacial reaction occurred and the reaction product was confirmed to be Al2Ti.Three kinds of pre-dispersion technologies were used before the settling process and different interfacial microstructures were found.Theoretical calculation and experimental results both indicated that the interfacial product which was embedded in the matrix strengthened the composites and improved the tensile strength.
文摘We propose a co-sintering process for effective fabrication of three-layered structure for direct-write planar waveguide. Processing parameters and optical properties of the waveguide was investigated.
文摘In textile finishing, stenters always draw considerable attention to newer inventions to boost up production via maximum utilization of energy. Prior to main drying or heat-setting chambers, intermediate heating of cylindrical system especially by steam has a direct blessing to moisture evaporation, processing speed, fabric quality and so on. Based on actual operational data, this study reveals the outcomes of a pre-heating module installed within a stenter. After employing the pre-heating system to knit fabrics of different structures and compositions, 23% - 61% moisture reduction was found and the speed of processing fabrics was increased simultaneously by 17% - 30% without any compromise on fabric quality. Moreover, no less than 8.21% savings in annual electricity consumption were observed.
基金Project supported by the National Natural Science Foundation of China(Nos.60936002,61025021,61434001,61574083)the State Key Development Program for Basic Research of China(No.2015CB352100)+3 种基金the National Key Project of Science and Technology(No.2011ZX02403-002)the Special Fund for Agroscientific Research in the Public Interest of China(No.201303107)supported by the Postdoctoral Fellowship(PDF)Program of the Natural Sciences and Engineering Research Council(NSERC)of CanadaChina’s Postdoctoral Science Foundation(CPSF)
文摘In recent years, flexible electronic devices have become a hot topic of scientific research. These flexible devices are the basis of flexible circuits, flexible batteries, flexible displays and electronic skins. Graphene-based materials are very promising for flexible electronic devices, due to their high mobility, high elasticity, a tunable band gap, quantum electronic transport and high mechanical strength. In this article, we review the recent progress of the fabrication process and the applications of graphene-based electronic devices, including thermal acoustic devices, thermal rectifiers, graphene-based nanogenerators, pressure sensors and graphene-based light-emitting diodes. In summary, although there are still a lot of challenges needing to be solved, graphene-based materials are very promising for various flexible device applications in the future.