自单层MoS_(2)光电晶体管问世以来,二维层状材料一直被认为是实现下一代新型光电器件与系统的最引人瞩目的候选材料之一.然而,大多数报道的二维层状材料光电探测器都存在一定的缺点,如响应率低、暗电流大、比探测率低、开关比低、响应...自单层MoS_(2)光电晶体管问世以来,二维层状材料一直被认为是实现下一代新型光电器件与系统的最引人瞩目的候选材料之一.然而,大多数报道的二维层状材料光电探测器都存在一定的缺点,如响应率低、暗电流大、比探测率低、开关比低、响应速率慢等.在本研究中,通过堆叠由大气压化学气相沉积技术所生长的MoS_(2)和SnS_(2)纳米片,制备出了多层SnS_(2)/少层MoS_(2)范德华异质结.相应的SnS_(2)/MoS_(2)异质结光电探测器展示出了具有竞争力的综合性能:大开关比(171)、高响应率(28.3 A W^(-1)),以及出色的比探测率(1.2×10^(13)Jones).此外,该器件还实现了响应/恢复时间低至1.38 ms/600μs的超快响应速率.其优异的性能与SnS_(2)/MoS_(2)异质结的Ⅱ型能带排列以及原位形成的无缝光浮栅的协同作用相关,这有助于分离光激发的电子-空穴对,并延长非平衡载流子的寿命.得益于出色的光敏性,该SnS_(2)/MoS_(2)器件实现了概念验证的光学成像应用.总体而言,本研究为实现具有优异综合性能的先进光电探测器提供了独特视角.展开更多
A fractional frequency transmission system(FFTS)is the most competitive choice for long distance transmission of offshore wind power,while the Hexverter,as a newly proposed direct AC/AC converter,is an attractive choi...A fractional frequency transmission system(FFTS)is the most competitive choice for long distance transmission of offshore wind power,while the Hexverter,as a newly proposed direct AC/AC converter,is an attractive choice for its power conversion.This paper proposes a novel control scheme characterizing the global stability and strong robustness of the Hexverter in FFTS applications,which are based on the interconnection and damping assignment passivity-based control(IDA-PBC)methodology.Firstly,the frequency decoupled model of the Hexverter is studied and then a port-controlled Hamiltonian(PCH)model is built.On this basis,the IDAPBC scheme of the Hexverter is designed.Considering the interference of system parameters and unmodeled dynamics,integrators are added to the IDA-PB controller to eliminate the steady-state error.In addition,the voltagebalancing control is applied in order to balance the capacitor DC voltages to obtain a better performance.Finally,the simulation results and experimental results are presented to verify the effectiveness and superiority of the IDA-PB controller.展开更多
A method of controlling the morphology of SnTe nanostructures produced by a simple chemical vapor deposition is presented, in which Au-containing catalysts with different Au concentrations are used to induce specific ...A method of controlling the morphology of SnTe nanostructures produced by a simple chemical vapor deposition is presented, in which Au-containing catalysts with different Au concentrations are used to induce specific growth behavior. Triangular SnTe nanoplates with a {100} dominated surface and {100}, {111} and {120} side facets were induced by AuSn catalysts, whereas 〈010〉 SnTe nanowires with four nonpolar {100} side-facets were produced using AusSn catalysts. Through detailed structural and chemical characterization, coupled with surface energy calculations, it is found that nanowire growth is thermodynamically controlled via a vapor-solid-solid growth mechanism, whereas nanoplate growth is kinetically controlled via a vapor-liquid-solid growth mechanism. Therefore, this study provides a fundamental understanding of the catalyst＇s role in the growth of IV-VI compound nanostructures.展开更多
Laser powder bed fusion(LPBF)is a timely important additive manufacturing technique that offers many opportunities for fabricating three-dimensional complex shaped components at a high resolution with short lead times...Laser powder bed fusion(LPBF)is a timely important additive manufacturing technique that offers many opportunities for fabricating three-dimensional complex shaped components at a high resolution with short lead times.This technique has been extensively employed in manufacturing Ti-6Al-4V parts for aerospace and biomedical applications.However,many challenges,including poor surface quality,porosity,anisotropy in microstructure and property,and difficulty in tailoring microstructure,still exist.In this paper,we review the recent progress in post-process treatment and its influence on the microstructure evolution and material performance,including tensile,fatigue,fracture toughness,creep,and corrosion properties.The contradictions in simultaneously achieving high strength/ductility and strength/fracture toughness/creep resistance have been identified.Furthermore,research gaps in understanding the effects of the emerging bi-modal microstructure on fatigue properties and fracture toughness require further investigation.展开更多
基金supported by the National Natural Science Foundation of China(U2001215,52272175,and 12104517)the Natural Science Foundation of Guangdong Province(2021A1515110403 and 2022A1515011487)+3 种基金the Science and Technology Projects in Guangzhou(202201011232)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(22qntd0101)the One-Hundred Talents Program of Sun Yat-sen Universitythe State Key Laboratory of Optoelectronic Materials and Technologies。
文摘自单层MoS_(2)光电晶体管问世以来,二维层状材料一直被认为是实现下一代新型光电器件与系统的最引人瞩目的候选材料之一.然而,大多数报道的二维层状材料光电探测器都存在一定的缺点,如响应率低、暗电流大、比探测率低、开关比低、响应速率慢等.在本研究中,通过堆叠由大气压化学气相沉积技术所生长的MoS_(2)和SnS_(2)纳米片,制备出了多层SnS_(2)/少层MoS_(2)范德华异质结.相应的SnS_(2)/MoS_(2)异质结光电探测器展示出了具有竞争力的综合性能:大开关比(171)、高响应率(28.3 A W^(-1)),以及出色的比探测率(1.2×10^(13)Jones).此外,该器件还实现了响应/恢复时间低至1.38 ms/600μs的超快响应速率.其优异的性能与SnS_(2)/MoS_(2)异质结的Ⅱ型能带排列以及原位形成的无缝光浮栅的协同作用相关,这有助于分离光激发的电子-空穴对,并延长非平衡载流子的寿命.得益于出色的光敏性,该SnS_(2)/MoS_(2)器件实现了概念验证的光学成像应用.总体而言,本研究为实现具有优异综合性能的先进光电探测器提供了独特视角.
基金supported by National Natural Science Foundation of China(No.51677142)Science and Technology Foundation of SGCC(Research on efficient integration of large scale long distance offshore wind farm and its key technologies in operation and control).
文摘A fractional frequency transmission system(FFTS)is the most competitive choice for long distance transmission of offshore wind power,while the Hexverter,as a newly proposed direct AC/AC converter,is an attractive choice for its power conversion.This paper proposes a novel control scheme characterizing the global stability and strong robustness of the Hexverter in FFTS applications,which are based on the interconnection and damping assignment passivity-based control(IDA-PBC)methodology.Firstly,the frequency decoupled model of the Hexverter is studied and then a port-controlled Hamiltonian(PCH)model is built.On this basis,the IDAPBC scheme of the Hexverter is designed.Considering the interference of system parameters and unmodeled dynamics,integrators are added to the IDA-PB controller to eliminate the steady-state error.In addition,the voltagebalancing control is applied in order to balance the capacitor DC voltages to obtain a better performance.Finally,the simulation results and experimental results are presented to verify the effectiveness and superiority of the IDA-PB controller.
基金This work was supported by the National Young 1000 Talent Plan, Pujiang Talent Plan in Shanghai, National Natural Science Foundation of China （Nos. 61322407, 11474058, and 11322441）, the Chinese Na- tional Science Fund for Talent Training in Basic Science （No. J1103204）, and Ten Thousand Talents Program for young talents. Part of the sample fabrication was performed at Fudan Nano-fabrication Laboratory. We acknowledge Yuanbo Zhang, Yizheng Wu, Zuimin Jiang, Likai Li, Boliang Chen for great assistance during the device fabrication and measurements.
文摘A method of controlling the morphology of SnTe nanostructures produced by a simple chemical vapor deposition is presented, in which Au-containing catalysts with different Au concentrations are used to induce specific growth behavior. Triangular SnTe nanoplates with a {100} dominated surface and {100}, {111} and {120} side facets were induced by AuSn catalysts, whereas 〈010〉 SnTe nanowires with four nonpolar {100} side-facets were produced using AusSn catalysts. Through detailed structural and chemical characterization, coupled with surface energy calculations, it is found that nanowire growth is thermodynamically controlled via a vapor-solid-solid growth mechanism, whereas nanoplate growth is kinetically controlled via a vapor-liquid-solid growth mechanism. Therefore, this study provides a fundamental understanding of the catalyst＇s role in the growth of IV-VI compound nanostructures.
基金funded by Australian Research Council IH130100008“Industrial Transformation Research Hub for Transforming Australia's Manufacturing Industry through High Value Additive Manufacturing”.
文摘Laser powder bed fusion(LPBF)is a timely important additive manufacturing technique that offers many opportunities for fabricating three-dimensional complex shaped components at a high resolution with short lead times.This technique has been extensively employed in manufacturing Ti-6Al-4V parts for aerospace and biomedical applications.However,many challenges,including poor surface quality,porosity,anisotropy in microstructure and property,and difficulty in tailoring microstructure,still exist.In this paper,we review the recent progress in post-process treatment and its influence on the microstructure evolution and material performance,including tensile,fatigue,fracture toughness,creep,and corrosion properties.The contradictions in simultaneously achieving high strength/ductility and strength/fracture toughness/creep resistance have been identified.Furthermore,research gaps in understanding the effects of the emerging bi-modal microstructure on fatigue properties and fracture toughness require further investigation.
