The Chinese economy is currently undergoing a digital transformation.New growth drivers are replacing old ones,creating a new development landscape.Countries with strong digital industries will be the first to reap th...The Chinese economy is currently undergoing a digital transformation.New growth drivers are replacing old ones,creating a new development landscape.Countries with strong digital industries will be the first to reap the benefits of digitalization.For China,the transformation to a digital economy is both of inevitability and heterogeneity fueled by dual circulations.Crowded out from more skill-based digitalized sectors,less-skilled labor moves to less digitalized sectors.New capital,industries and technology clusters emerge as new drivers of manufacturing and service sector development.With its large domestic market and industrial competitiveness,China has fostered a new development landscape of“dual circulations”.展开更多
This study reports a new model of an air standard Dual-Miller cycle(DMC) with two polytropic processes and heat transfer loss.The two reversible adiabatic processes which could not be realized in practice are replaced...This study reports a new model of an air standard Dual-Miller cycle(DMC) with two polytropic processes and heat transfer loss.The two reversible adiabatic processes which could not be realized in practice are replaced with two polytropic processes in order to more accurately reflect the practical working performance. The heat transfer loss is taken into account. The expressions of power output, thermal efficiency, entropy generation rate(EGR) and ecological function are addressed using finite-time thermodynamic theory. Through numerical calculations, the influences of compression ratio, cut-off ratio and polytropic exponent on the performance are thermodynamically analyzed. The model can be simplified to other cycle models under specific conditions, which means the results have an certain universality and may be helpful in the design of practical heat engines. It is shown that the entropy generation minimization does not always lead to the best system performance.展开更多
This Letter theoretically and experimentally studies the response of photonic switching in a channel-interleaved photonic analog-to-digital converter(PADC) with high sampling rate and wide input frequency range. A fig...This Letter theoretically and experimentally studies the response of photonic switching in a channel-interleaved photonic analog-to-digital converter(PADC) with high sampling rate and wide input frequency range. A figure of merit(FoM) is introduced to evaluate the switching response of the PADC when a dual-output Mach–Zehnder modulator(MZM) serves as the photonic switch to parallelize the sampled pulse train into two channels. After the optimization of the FoM and utilization of the channel-mismatch compensation algorithm,the system bandwidth of PADC is expanded and the signal-to-distortion ratio is enhanced.展开更多
A four-element compact dual-band patch antenna having a common ground plane operating at 28/38 GHz is proposed formillimeter-wave communication systems in this paper.Themultiple-input-multiple-output(MIMO)antenna geom...A four-element compact dual-band patch antenna having a common ground plane operating at 28/38 GHz is proposed formillimeter-wave communication systems in this paper.Themultiple-input-multiple-output(MIMO)antenna geometry consists of a slotted ellipse enclosed within a hollow circle which is orthogonally rotated with a connected partial ground at the back.The overall size of the four elements MIMO antenna is 2.24λ×2.24λ(at 27.12GHz).The prototype of four-element MIMOresonator is designed and printed using Rogers RTDuroid 5880 withε_(r)=2.2 and loss tangent=0.0009 and having a thickness of 0.8 mm.It covers dual-band having a fractional bandwidth of 15.7%(27.12-31.34 GHz)and 4.2%(37.21-38.81 GHz)for millimeter-wave applications with a gain of more than 4 dBi at both bands.The proposed antenna analysis in terms ofMIMOdiversity parameters(Envelope Correlation Coefficient(ECC)and Diversity Gain(DG))is also carried out.The experimental result in terms of reflection coefficient,radiation pattern,gain and MIMOdiversity parameter correlates very well with the simulated ones that show the potential of the proposed design for MIMO applications at millimeter-wave frequencies.展开更多
基金国家社科基金重大项目“新旧动能转换机制设计与路径选择”(批准号:18Z D A077)南京大学长江三角洲经济社会发展研究中心暨区域经济转型与管理变革协同创新中心联合招标重大项目“长三角区域世界级产业集聚培育和协调发展”(批准号:CYD-2020019)。
文摘The Chinese economy is currently undergoing a digital transformation.New growth drivers are replacing old ones,creating a new development landscape.Countries with strong digital industries will be the first to reap the benefits of digitalization.For China,the transformation to a digital economy is both of inevitability and heterogeneity fueled by dual circulations.Crowded out from more skill-based digitalized sectors,less-skilled labor moves to less digitalized sectors.New capital,industries and technology clusters emerge as new drivers of manufacturing and service sector development.With its large domestic market and industrial competitiveness,China has fostered a new development landscape of“dual circulations”.
基金supported by the National Natural Science Foundation of China(Grant No.51576207)
文摘This study reports a new model of an air standard Dual-Miller cycle(DMC) with two polytropic processes and heat transfer loss.The two reversible adiabatic processes which could not be realized in practice are replaced with two polytropic processes in order to more accurately reflect the practical working performance. The heat transfer loss is taken into account. The expressions of power output, thermal efficiency, entropy generation rate(EGR) and ecological function are addressed using finite-time thermodynamic theory. Through numerical calculations, the influences of compression ratio, cut-off ratio and polytropic exponent on the performance are thermodynamically analyzed. The model can be simplified to other cycle models under specific conditions, which means the results have an certain universality and may be helpful in the design of practical heat engines. It is shown that the entropy generation minimization does not always lead to the best system performance.
基金partially supported by the National Natural Science Foundation of China(Nos.61822508,61571292,and 61535006)
文摘This Letter theoretically and experimentally studies the response of photonic switching in a channel-interleaved photonic analog-to-digital converter(PADC) with high sampling rate and wide input frequency range. A figure of merit(FoM) is introduced to evaluate the switching response of the PADC when a dual-output Mach–Zehnder modulator(MZM) serves as the photonic switch to parallelize the sampled pulse train into two channels. After the optimization of the FoM and utilization of the channel-mismatch compensation algorithm,the system bandwidth of PADC is expanded and the signal-to-distortion ratio is enhanced.
基金This work is supported by the Moore4Medical Project,funded within ECSEL JU in collaboration with the EU H2020 Framework Programme(H2020/2014-2020)under Grant Agreement H2020-ECSEL-2019-IA-876190Fundacao para a Ciência eTecnologia(ECSEL/0006/2019)This work is also funded by the FCT/MEC through national funds and when applicable co-financed by the ERDF,under the PT2020 Partnership Agreement under the UID/EEA/50008/2020 Project.
文摘A four-element compact dual-band patch antenna having a common ground plane operating at 28/38 GHz is proposed formillimeter-wave communication systems in this paper.Themultiple-input-multiple-output(MIMO)antenna geometry consists of a slotted ellipse enclosed within a hollow circle which is orthogonally rotated with a connected partial ground at the back.The overall size of the four elements MIMO antenna is 2.24λ×2.24λ(at 27.12GHz).The prototype of four-element MIMOresonator is designed and printed using Rogers RTDuroid 5880 withε_(r)=2.2 and loss tangent=0.0009 and having a thickness of 0.8 mm.It covers dual-band having a fractional bandwidth of 15.7%(27.12-31.34 GHz)and 4.2%(37.21-38.81 GHz)for millimeter-wave applications with a gain of more than 4 dBi at both bands.The proposed antenna analysis in terms ofMIMOdiversity parameters(Envelope Correlation Coefficient(ECC)and Diversity Gain(DG))is also carried out.The experimental result in terms of reflection coefficient,radiation pattern,gain and MIMOdiversity parameter correlates very well with the simulated ones that show the potential of the proposed design for MIMO applications at millimeter-wave frequencies.
