1. IntroductionA large number of networks for realizing first and second order transfer functions using a currentconveyor have been reported in the literature. Especially, the networks that can offer highinput impedan...1. IntroductionA large number of networks for realizing first and second order transfer functions using a currentconveyor have been reported in the literature. Especially, the networks that can offer highinput impedance attract attention, for high input impedance has the advantage that the networksmay be used in cascade without requiring impedance matching device. In the Higashimura and展开更多
As a result of the exponential growing rate of worldwide Internet usage, satellite systems are required to support broadband Internet applications. The transmission control protocol （TCP） which is widely used in the...As a result of the exponential growing rate of worldwide Internet usage, satellite systems are required to support broadband Internet applications. The transmission control protocol （TCP） which is widely used in the Internet, performs very well on wired networks. However, in the case of satellite channels, clue to the delay and transmission errors, TCP performance degrades significantly and bandwidth of satellite links can not be fully utilized. To improve the TCP performance, a new idea of placing a TCP spoofing proxy in the satellite is considered. A Novel Satellite Transport Protocol （NSTP） which takes advantage of the special properties of the satellite channel is also proposed. By using simulation, as compared with traditional TCPs, the on-board spoofing proxy integrated with the special transport protocol can significantly enhance throughput performance on the high BER satellite link, the time needed to transfer files and the bandwidth used in reverse path are sharply reduced.展开更多
A novel scheme for all-optical inverted wavelength conversion with 40-Gb/s pseudorandom bit sequences (PRBSs) based on a modified terahertz optical asymmetric demultiplexer (TOAD) is proposed. The performance of the p...A novel scheme for all-optical inverted wavelength conversion with 40-Gb/s pseudorandom bit sequences (PRBSs) based on a modified terahertz optical asymmetric demultiplexer (TOAD) is proposed. The performance of the proposed wavelength converter is analyzed in term of extinction ratio (ER) through numerical simulations. For a typical ER of 10 dB, some key characteristic parameters of the semiconductor optical amplifier (SOA) are designed. With the properly designed parameters, a high quality eye diagram is achievable, indicating that the amplitude fluctuation of the output signal is effectively reduced.展开更多
This review emphasizes the recent advancements and prospects of thin-film kesterite-based photovoltaic(PV)applications using magnesium,iron and nickel.The quest for novel materials employed in solar cells has resulted...This review emphasizes the recent advancements and prospects of thin-film kesterite-based photovoltaic(PV)applications using magnesium,iron and nickel.The quest for novel materials employed in solar cells has resulted in incorporating these elements into the composition of kesterite as substitutes or modifiers(dopants)for zinc.This integration has induced notable repercussions on the structural,optoelectronics and morphological properties,which are reviewed.The first section of this paper offers a comprehensive review of the general characteristics of kesterite minerals.These crucial materials exhibit a high absorption coefficient(104 cm-1)and an optical band gap of 1.0-1.8 eV.Moreover,they are free of critical raw materials,non-toxic and sustainable.The second section depicts the substitution or modification of zinc by magnesium in kesterite.Additionally,this paper provides a comprehensive review of the quaternary and pentanary systems Cu_(2)MgSn(S,Se)_(4) and Cu_(2)Zn_(1-x)Mg_(x)SnS_(4),highlighting their advantages and drawbacks.In the last section,a review of the quaternary or pentanary systems is conducted,namely Cu_(2)ZnxFe_(1-x)SnS_(4) and Cu_(2)ZnxNi_(1-x)SnS_(4),along with their effects on optoelectronic properties.In conclusion,various methods for obtaining modified or substituted kesterite materials using magnesium,iron and nickel have demonstrated sustainability,scalability for industrial production and potential candidacy as substitutes for conventional PV materials.The prospects for pentanary materials(Cu_(2)Zn_(1-x)Mg_(x)SnS_(4),Cu_(2)Zn_(1-x)FexSnS_(4) and Cu_(2)Zn_(1-x)NixSnS_(4))are to overcome the efficiency record of kesterite reported in 2014,which was 12.6%for Cu_(2)ZnSn(S,Se)_(4),and to enhance its optoelectronic properties through synthesis conditions that comply with the principles of green chemistry.展开更多
文摘1. IntroductionA large number of networks for realizing first and second order transfer functions using a currentconveyor have been reported in the literature. Especially, the networks that can offer highinput impedance attract attention, for high input impedance has the advantage that the networksmay be used in cascade without requiring impedance matching device. In the Higashimura and
文摘As a result of the exponential growing rate of worldwide Internet usage, satellite systems are required to support broadband Internet applications. The transmission control protocol （TCP） which is widely used in the Internet, performs very well on wired networks. However, in the case of satellite channels, clue to the delay and transmission errors, TCP performance degrades significantly and bandwidth of satellite links can not be fully utilized. To improve the TCP performance, a new idea of placing a TCP spoofing proxy in the satellite is considered. A Novel Satellite Transport Protocol （NSTP） which takes advantage of the special properties of the satellite channel is also proposed. By using simulation, as compared with traditional TCPs, the on-board spoofing proxy integrated with the special transport protocol can significantly enhance throughput performance on the high BER satellite link, the time needed to transfer files and the bandwidth used in reverse path are sharply reduced.
文摘A novel scheme for all-optical inverted wavelength conversion with 40-Gb/s pseudorandom bit sequences (PRBSs) based on a modified terahertz optical asymmetric demultiplexer (TOAD) is proposed. The performance of the proposed wavelength converter is analyzed in term of extinction ratio (ER) through numerical simulations. For a typical ER of 10 dB, some key characteristic parameters of the semiconductor optical amplifier (SOA) are designed. With the properly designed parameters, a high quality eye diagram is achievable, indicating that the amplitude fluctuation of the output signal is effectively reduced.
文摘This review emphasizes the recent advancements and prospects of thin-film kesterite-based photovoltaic(PV)applications using magnesium,iron and nickel.The quest for novel materials employed in solar cells has resulted in incorporating these elements into the composition of kesterite as substitutes or modifiers(dopants)for zinc.This integration has induced notable repercussions on the structural,optoelectronics and morphological properties,which are reviewed.The first section of this paper offers a comprehensive review of the general characteristics of kesterite minerals.These crucial materials exhibit a high absorption coefficient(104 cm-1)and an optical band gap of 1.0-1.8 eV.Moreover,they are free of critical raw materials,non-toxic and sustainable.The second section depicts the substitution or modification of zinc by magnesium in kesterite.Additionally,this paper provides a comprehensive review of the quaternary and pentanary systems Cu_(2)MgSn(S,Se)_(4) and Cu_(2)Zn_(1-x)Mg_(x)SnS_(4),highlighting their advantages and drawbacks.In the last section,a review of the quaternary or pentanary systems is conducted,namely Cu_(2)ZnxFe_(1-x)SnS_(4) and Cu_(2)ZnxNi_(1-x)SnS_(4),along with their effects on optoelectronic properties.In conclusion,various methods for obtaining modified or substituted kesterite materials using magnesium,iron and nickel have demonstrated sustainability,scalability for industrial production and potential candidacy as substitutes for conventional PV materials.The prospects for pentanary materials(Cu_(2)Zn_(1-x)Mg_(x)SnS_(4),Cu_(2)Zn_(1-x)FexSnS_(4) and Cu_(2)Zn_(1-x)NixSnS_(4))are to overcome the efficiency record of kesterite reported in 2014,which was 12.6%for Cu_(2)ZnSn(S,Se)_(4),and to enhance its optoelectronic properties through synthesis conditions that comply with the principles of green chemistry.
