Hydrogenated amorphous carbon films were fabricated by using layer-by-layer deposition method and hydrogen dilution method in a small d.c.-assisted plasma enhanced chemical vapor deposition system. It was found that t...Hydrogenated amorphous carbon films were fabricated by using layer-by-layer deposition method and hydrogen dilution method in a small d.c.-assisted plasma enhanced chemical vapor deposition system. It was found that the hydrogen plasma treatment could change the sp2/sp3 ratio to some extent by chemical etching. The improvements of field emission characteristics were observed compared with that from conventionally deposited a-C films, which can be attributed to the large field enhancement effect due to the inhomogeneous distribution of nanometer scale sp2 clusters and the reduction of the surface emission barrier due to the hydrogen termination.展开更多
A simple process to fabricate chain-like carbon nanotube （CNT） films by microwave plasma-enhanced chemical vapor deposition （MPCVD） was developed successfully. Prior to deposition, the Ti/Al2O3 substrates were gro...A simple process to fabricate chain-like carbon nanotube （CNT） films by microwave plasma-enhanced chemical vapor deposition （MPCVD） was developed successfully. Prior to deposition, the Ti/Al2O3 substrates were ground with Fe-doped SiO2 powder. The nano-structure of the deposited films was analyzed by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and Raman spectroscopy. The field electron emission characteristics of the chain-like carbon nanotube films were measured under the vacuum of 10-5 Pa. The low turn-on field of 0.80 V/μm and the emission current density of 8.5 mA/cm2 at the electric field of 3.0 V/μm are obtained. Based on the above results, chain-like carbon nanotube films probably have important applications in cold cathode materials and electrode materials.展开更多
We theoretically investigate the microwave absorption properties of hydrogen plasma in iron-catalyzed high- pressure disproportionation-grown carbon nanotubes under an external static magnetic field in the frequency r...We theoretically investigate the microwave absorption properties of hydrogen plasma in iron-catalyzed high- pressure disproportionation-grown carbon nanotubes under an external static magnetic field in the frequency range 0.3 GHz to 30 GHz, using the Maxwell equations in conjunction with a general expression for the effective complex permittivity of magnetized plasma known as the Appleton Hartree formula. The effects of the external static magnetic field intensity and the incident microwave propagation direction on the microwave absorption of hydrogen plasma in CNTs are studied in detail. The numerical results indicate that the microwave absorption properties of hydrogen plasma in iron-catalyzed high-pressure disproportionation-grown carbon nanotubes can be obviously improved when the exter- nal static magnetic field is applied to the material. It is found that the specified frequency microwave can be strongly absorbed by the hydrogen plasma in iron-catalyzed high-pressure disproportionation-grown carbon nanotubes over a wide range of incidence angles by adjusting the external magnetic field intensity and the parameters of the hydrogen plasma.展开更多
Purpose-The purpose of this paper is to introduce new implementations for parallel processing applications using bijective systolic networks and the corresponding carbon-based field emission controlled switching.The d...Purpose-The purpose of this paper is to introduce new implementations for parallel processing applications using bijective systolic networks and the corresponding carbon-based field emission controlled switching.The developed implementations are performed in the reversible domain to perform the required bijective parallel computing,where the implementations for parallel computations that utilize the presented field-emission controlled switching and their corresponding m-ary(many-valued)extensions for the use in nano systolic networks are introduced.The first part of the paper presents important fundamentals with regards to systolic computing and carbon-based field emission that will be utilized in the implementations within the second part of the paper.Design/methodology/approach-The introduced systolic systems utilize recent findings in field emission and nano applications to implement the functionality of the basic bijective systolic network.This includes many-valued systolic computing via field emission techniques using carbon-based nanotubes and nanotips.The realization of bijective logic circuits in current and emerging technologies can be very important for various reasons.The reduction of power consumption is a major requirement for the circuit design in future technologies,and thus,the new nano systolic circuits can play an important role in the design of circuits that consume minimal power for future applications such as in low-power signal processing.In addition,the implemented bijective systems can be utilized to implement massive parallel processing and thus obtaining very high processing performance,where the implementation will also utilize the significant size reduction within the nano domain.The extensions of implementations to field emission-based many-valued systolic networks using the introduced bijective nano systolic architectures are also presented.Findings-Novel bijective systolic architectures using nano-based field emission implementations are introduced in this paper,and the implementation using the general scheme of many-valued computing is presented.The carbon-based field emission implementation of nano systolic networks is also introduced.This is accomplished using the introduced field emission carbon-based devices,where field emission from carbon nanotubes and nano-apex carbon fibers is utilized.The implementations of the many-valued bijective systolic networks utilizing the introduced nano-based architectures are also presented.Originality/value-The introduced bijective systolic implementations form new important directions in the systolic realizations using the newly emerging nano-based technologies.The 2-to-1 multiplexer is a basic building block in“switch logic,”where in switch logic,a logic circuit is realized as a combination of switches rather than a combination of logic gates as in the gate logic,which proves to be less costly in synthesizing multiplexer-based wide variety of modern circuits and systems since nano implementations exist in very compact space where carbon-based devices switch reliably using much less power than silicon-based devices.The introduced implementations for nano systolic computation are new and interesting for the design in future nanotechnologies that require optimal design specifications of minimum power consumption and minimum size layout such as in low-power control of autonomous robots and in the adiabatic low-power very-large-scale-integration circuit design for signal processing applications.展开更多
Purpose–The purpose of this paper is to introduce new implementations for parallel processing applications using bijective systolic networks and their corresponding carbon-based field emission controlled switching.Th...Purpose–The purpose of this paper is to introduce new implementations for parallel processing applications using bijective systolic networks and their corresponding carbon-based field emission controlled switching.The developed implementations are performed in the reversible domain to perform the required bijective parallel computing,where the implementations for parallel computations that utilize the presented field-emission controlled switching and their corresponding many-valued(m-ary)extensions for the use in nano systolic networks are introduced.The second part of the paper introduces the implementation of systolic computing using two-to-one controlled switching via carbon-based field emission that were presented in the first part of the paper,and the computational extension to the general case of many-valued(m-ary)systolic networks utilizing many-to-one carbon-based field emission is also introduced.Design/methodology/approach–The introduced systolic systems utilize recent findings in field emission and nano applications to implement the functionality of the basic bijective systolic network.This includes many-valued systolic computing via field-emission techniques using carbon-based nanotubes and nanotips.The realization of bijective logic circuits in current and emerging technologies can be very important for various reasons.The reduction of power consumption is a major requirement for the circuit design in future technologies,and thus,the new nano systolic circuits can play an important role in the design of circuits that consume minimal power for future applications such as in low-power signal processing.In addition,the implemented bijective systems can be utilized to implement massive parallel processing and thus obtaining very high processing performance,where the implementation will also utilize the significant size reduction within the nano domain.The extensions of implementations to field emission-based many-valued systolic networks using the introduced bijective nano systolic architectures are also presented.Findings–Novel bijective systolic architectures using nano-based field emission implementations are introduced in this paper,and the implementation using the general scheme of many-valued computing is presented.The carbon-based field emission implementation of nano systolic networks is also introduced.This is accomplished using the introduced field-emission carbon-based devices,where field emission from carbon nanotubes and nano-apex carbon fibersisutilized.The implementationsof the many-valued bijective systolic networks utilizing the introduced nano-based architectures are also presented.Practical implications–The introduced bijective systolic implementations form new important directions in the systolic realizations using the newly emerging nano-based technologies.The 2-to-1 multiplexer is a basic building block in“switch logic,”where in switch logic,a logic circuit is realized as a combination of switches rather than a combination of logic gates as in the gate logic,which proves to be less costly in synthesizing multiplexer-based wide variety of modern circuits and systems since nano implementations exist in very compact space where carbon-based devices switch reliably using much less power than silicon-based devices.The introduced implementations for nano systolic computation are new and interesting for the design in future nanotechnologies that require optimal design specifications of minimum power consumption and minimum size layout such as in low-power control of autonomous robots and in the adiabatic low-power VLSI circuit design for signal processing applications.Originality/value–The introduced bijective systolic implementations form new important directions in the systolic realizations utilizing the newly emerging nanotechnologies.The introduced implementations for nano systolic computation are new and interesting for the design in future nanotechnologies that require optimal design specifications of high performance,minimum power and minimum size.展开更多
Experimental investigations on the vacuum outgassing of a carbon nanotube （CNT） cathode with high-intensity pulsed electron emission on a 2 MeV linear induction accelerator injector are presented. Under the 1.60 MV ...Experimental investigations on the vacuum outgassing of a carbon nanotube （CNT） cathode with high-intensity pulsed electron emission on a 2 MeV linear induction accelerator injector are presented. Under the 1.60 MV diode voltage, the CNT cathode could provide 1.67 kA electron beam with the amount of outgassing of about 0.51 Pa.L. It is found that the amount of outgassing, which determines the cathode emission current, depends on the diode voltage and the vacuum.展开更多
在Cu基底上,采用催化热解生长法制备了石墨化程度较高的碳纳米管阴极.当电子束能量达到1 Me V、梯度约为60 k V/ns时,发射束流强度达到15 k A,相应密度约为1 k A/cm2,束压、束流响应快,波形间几无延时.以50 Hz重复频率、约15 GW束功率...在Cu基底上,采用催化热解生长法制备了石墨化程度较高的碳纳米管阴极.当电子束能量达到1 Me V、梯度约为60 k V/ns时,发射束流强度达到15 k A,相应密度约为1 k A/cm2,束压、束流响应快,波形间几无延时.以50 Hz重复频率、约15 GW束功率强流发射时,波形稳定,随着频率增高,稳定性降低.发射炮次达1000后,表面形貌保持完整、界面无脱附;束压与束流基本满足空间电荷限制定律,发射机理属闪络型等离子体发射,等离子体速度约为3.9 cm/μs.展开更多
基金supported by the NSFof China(59802004)Jiangsu Province,China(BK99047)+1 种基金RGC of Hongkong(No.CUHK 4173/98E)support of Groucher Foundation of Hong Kong
文摘Hydrogenated amorphous carbon films were fabricated by using layer-by-layer deposition method and hydrogen dilution method in a small d.c.-assisted plasma enhanced chemical vapor deposition system. It was found that the hydrogen plasma treatment could change the sp2/sp3 ratio to some extent by chemical etching. The improvements of field emission characteristics were observed compared with that from conventionally deposited a-C films, which can be attributed to the large field enhancement effect due to the inhomogeneous distribution of nanometer scale sp2 clusters and the reduction of the surface emission barrier due to the hydrogen termination.
文摘A simple process to fabricate chain-like carbon nanotube （CNT） films by microwave plasma-enhanced chemical vapor deposition （MPCVD） was developed successfully. Prior to deposition, the Ti/Al2O3 substrates were ground with Fe-doped SiO2 powder. The nano-structure of the deposited films was analyzed by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and Raman spectroscopy. The field electron emission characteristics of the chain-like carbon nanotube films were measured under the vacuum of 10-5 Pa. The low turn-on field of 0.80 V/μm and the emission current density of 8.5 mA/cm2 at the electric field of 3.0 V/μm are obtained. Based on the above results, chain-like carbon nanotube films probably have important applications in cold cathode materials and electrode materials.
基金Project supported by the Science Research Program of Hunan Province, China (Grant No. 2010FJ4092)the National Natural Science Foundation of China (Grant No. 11075073)
文摘We theoretically investigate the microwave absorption properties of hydrogen plasma in iron-catalyzed high- pressure disproportionation-grown carbon nanotubes under an external static magnetic field in the frequency range 0.3 GHz to 30 GHz, using the Maxwell equations in conjunction with a general expression for the effective complex permittivity of magnetized plasma known as the Appleton Hartree formula. The effects of the external static magnetic field intensity and the incident microwave propagation direction on the microwave absorption of hydrogen plasma in CNTs are studied in detail. The numerical results indicate that the microwave absorption properties of hydrogen plasma in iron-catalyzed high-pressure disproportionation-grown carbon nanotubes can be obviously improved when the exter- nal static magnetic field is applied to the material. It is found that the specified frequency microwave can be strongly absorbed by the hydrogen plasma in iron-catalyzed high-pressure disproportionation-grown carbon nanotubes over a wide range of incidence angles by adjusting the external magnetic field intensity and the parameters of the hydrogen plasma.
基金This research was performed during sabbatical leave in 2015-2016 granted to the author from The University of Jordan and spent at Philadelphia University.
文摘Purpose-The purpose of this paper is to introduce new implementations for parallel processing applications using bijective systolic networks and the corresponding carbon-based field emission controlled switching.The developed implementations are performed in the reversible domain to perform the required bijective parallel computing,where the implementations for parallel computations that utilize the presented field-emission controlled switching and their corresponding m-ary(many-valued)extensions for the use in nano systolic networks are introduced.The first part of the paper presents important fundamentals with regards to systolic computing and carbon-based field emission that will be utilized in the implementations within the second part of the paper.Design/methodology/approach-The introduced systolic systems utilize recent findings in field emission and nano applications to implement the functionality of the basic bijective systolic network.This includes many-valued systolic computing via field emission techniques using carbon-based nanotubes and nanotips.The realization of bijective logic circuits in current and emerging technologies can be very important for various reasons.The reduction of power consumption is a major requirement for the circuit design in future technologies,and thus,the new nano systolic circuits can play an important role in the design of circuits that consume minimal power for future applications such as in low-power signal processing.In addition,the implemented bijective systems can be utilized to implement massive parallel processing and thus obtaining very high processing performance,where the implementation will also utilize the significant size reduction within the nano domain.The extensions of implementations to field emission-based many-valued systolic networks using the introduced bijective nano systolic architectures are also presented.Findings-Novel bijective systolic architectures using nano-based field emission implementations are introduced in this paper,and the implementation using the general scheme of many-valued computing is presented.The carbon-based field emission implementation of nano systolic networks is also introduced.This is accomplished using the introduced field emission carbon-based devices,where field emission from carbon nanotubes and nano-apex carbon fibers is utilized.The implementations of the many-valued bijective systolic networks utilizing the introduced nano-based architectures are also presented.Originality/value-The introduced bijective systolic implementations form new important directions in the systolic realizations using the newly emerging nano-based technologies.The 2-to-1 multiplexer is a basic building block in“switch logic,”where in switch logic,a logic circuit is realized as a combination of switches rather than a combination of logic gates as in the gate logic,which proves to be less costly in synthesizing multiplexer-based wide variety of modern circuits and systems since nano implementations exist in very compact space where carbon-based devices switch reliably using much less power than silicon-based devices.The introduced implementations for nano systolic computation are new and interesting for the design in future nanotechnologies that require optimal design specifications of minimum power consumption and minimum size layout such as in low-power control of autonomous robots and in the adiabatic low-power very-large-scale-integration circuit design for signal processing applications.
文摘Purpose–The purpose of this paper is to introduce new implementations for parallel processing applications using bijective systolic networks and their corresponding carbon-based field emission controlled switching.The developed implementations are performed in the reversible domain to perform the required bijective parallel computing,where the implementations for parallel computations that utilize the presented field-emission controlled switching and their corresponding many-valued(m-ary)extensions for the use in nano systolic networks are introduced.The second part of the paper introduces the implementation of systolic computing using two-to-one controlled switching via carbon-based field emission that were presented in the first part of the paper,and the computational extension to the general case of many-valued(m-ary)systolic networks utilizing many-to-one carbon-based field emission is also introduced.Design/methodology/approach–The introduced systolic systems utilize recent findings in field emission and nano applications to implement the functionality of the basic bijective systolic network.This includes many-valued systolic computing via field-emission techniques using carbon-based nanotubes and nanotips.The realization of bijective logic circuits in current and emerging technologies can be very important for various reasons.The reduction of power consumption is a major requirement for the circuit design in future technologies,and thus,the new nano systolic circuits can play an important role in the design of circuits that consume minimal power for future applications such as in low-power signal processing.In addition,the implemented bijective systems can be utilized to implement massive parallel processing and thus obtaining very high processing performance,where the implementation will also utilize the significant size reduction within the nano domain.The extensions of implementations to field emission-based many-valued systolic networks using the introduced bijective nano systolic architectures are also presented.Findings–Novel bijective systolic architectures using nano-based field emission implementations are introduced in this paper,and the implementation using the general scheme of many-valued computing is presented.The carbon-based field emission implementation of nano systolic networks is also introduced.This is accomplished using the introduced field-emission carbon-based devices,where field emission from carbon nanotubes and nano-apex carbon fibersisutilized.The implementationsof the many-valued bijective systolic networks utilizing the introduced nano-based architectures are also presented.Practical implications–The introduced bijective systolic implementations form new important directions in the systolic realizations using the newly emerging nano-based technologies.The 2-to-1 multiplexer is a basic building block in“switch logic,”where in switch logic,a logic circuit is realized as a combination of switches rather than a combination of logic gates as in the gate logic,which proves to be less costly in synthesizing multiplexer-based wide variety of modern circuits and systems since nano implementations exist in very compact space where carbon-based devices switch reliably using much less power than silicon-based devices.The introduced implementations for nano systolic computation are new and interesting for the design in future nanotechnologies that require optimal design specifications of minimum power consumption and minimum size layout such as in low-power control of autonomous robots and in the adiabatic low-power VLSI circuit design for signal processing applications.Originality/value–The introduced bijective systolic implementations form new important directions in the systolic realizations utilizing the newly emerging nanotechnologies.The introduced implementations for nano systolic computation are new and interesting for the design in future nanotechnologies that require optimal design specifications of high performance,minimum power and minimum size.
文摘Experimental investigations on the vacuum outgassing of a carbon nanotube （CNT） cathode with high-intensity pulsed electron emission on a 2 MeV linear induction accelerator injector are presented. Under the 1.60 MV diode voltage, the CNT cathode could provide 1.67 kA electron beam with the amount of outgassing of about 0.51 Pa.L. It is found that the amount of outgassing, which determines the cathode emission current, depends on the diode voltage and the vacuum.
文摘在Cu基底上,采用催化热解生长法制备了石墨化程度较高的碳纳米管阴极.当电子束能量达到1 Me V、梯度约为60 k V/ns时,发射束流强度达到15 k A,相应密度约为1 k A/cm2,束压、束流响应快,波形间几无延时.以50 Hz重复频率、约15 GW束功率强流发射时,波形稳定,随着频率增高,稳定性降低.发射炮次达1000后,表面形貌保持完整、界面无脱附;束压与束流基本满足空间电荷限制定律,发射机理属闪络型等离子体发射,等离子体速度约为3.9 cm/μs.
