This study employs a data-driven methodology that embeds the principle of dimensional invariance into an artificial neural network to automatically identify dominant dimensionless quantities in the penetration of rod ...This study employs a data-driven methodology that embeds the principle of dimensional invariance into an artificial neural network to automatically identify dominant dimensionless quantities in the penetration of rod projectiles into semi-infinite metal targets from experimental measurements.The derived mathematical expressions of dimensionless quantities are simplified by the examination of the exponent matrix and coupling relationships between feature variables.As a physics-based dimension reduction methodology,this way reduces high-dimensional parameter spaces to descriptions involving only a few physically interpretable dimensionless quantities in penetrating cases.Then the relative importance of various dimensionless feature variables on the penetration efficiencies for four impacting conditions is evaluated through feature selection engineering.The results indicate that the selected critical dimensionless feature variables by this synergistic method,without referring to the complex theoretical equations and aiding in the detailed knowledge of penetration mechanics,are in accordance with those reported in the reference.Lastly,the determined dimensionless quantities can be efficiently applied to conduct semi-empirical analysis for the specific penetrating case,and the reliability of regression functions is validated.展开更多
The band structure, density of states, optical properties, carrier mobility, and loss function of graphene, black phosphorus（BP）, and molybdenum disulfide（MoS_2） were investigated by the first-principles method wi...The band structure, density of states, optical properties, carrier mobility, and loss function of graphene, black phosphorus（BP）, and molybdenum disulfide（MoS_2） were investigated by the first-principles method with the generalized-gradient approximation. The graphene was a zero-band-gap semiconductor. The band gaps of BP and MoS_2 were strongly dependent on the number of layers. The relationships between layers and band gap were built to predict the band gap of few-layer BP and MoS_2. The absorption showed an explicit anisotropy for light polarized in（1 0 0） and（0 0 1） directions of graphene, BP,and MoS_2. This behavior may be readily detected in spectroscopic measurements and exploited for optoelectronic applications. Moreover, graphene（5.27 × 10~4 cm^2·V^（-1）·s^（-1））, BP（1.5 × 10~4 cm^2·V^（-1）·s^（-1））, and MoS_2（2.57×102 cm2·V-1·s-1）have high carrier mobility. These results show that graphene, BP, and MoS_2 are promising candidates for future electronic applications.展开更多
Prussian blue analogues(PBAs) are considered as superior cathode materials for potassium-ion batteries(PIBs) because of their three-dimensional open framework structure,high stability,and low cost.However,the intrinsi...Prussian blue analogues(PBAs) are considered as superior cathode materials for potassium-ion batteries(PIBs) because of their three-dimensional open framework structure,high stability,and low cost.However,the intrinsic lattice defects and low potassium content typically results in poor rate and cycling performance,thus limited their practical applications.In this work,high-quality K1.64FeFe(CN)6(PW-HQ)material with less crystalline water(6.21%) and high potassium content(1.64 mol^(-1)) was successfully synthesized by a novel coprecipitation method with potassium citrate(K-CA) and potassium chloride(KCl) addition.Specifically,the electrode delivers a reversible capacity of 113.1 mA h g^(-1)at the current rate of 50 mA g^(-1)with~100% coulombic efficiency.Besides,the electrode retained 90% reversible capacity at 500 mA g^(-1)current density after 1000 cycles,indicating only 0.01% capacity decay per cycle.Moreover,we have revealed that the introduction of K-CA controlled the chelating rate of Fe(Ⅱ) and the addition of KCl increased the K+content,hence improving the capacity and stability of the asprepared electrodes.Structural evolution and potassium storage mechanism were further investigated by detailed ex-situ X-ray diffraction and in-situ Raman measurements,which demonstrated reversible potassiation/depotassiation behavior and negligible volume change during the electrochemical process.In general,this work provides an efficient strategy to eliminate water contents in Prussian blue cathode and improve its electrochemical performance,which plays a key role in promoting the industrialization of potassium ion batteries.展开更多
Developing an interplay between the local morphological character and its local photovoltaic(PV)parameters in a perovskite thin film is essential for guiding the construction of highly-efficient perovskite solar cells...Developing an interplay between the local morphological character and its local photovoltaic(PV)parameters in a perovskite thin film is essential for guiding the construction of highly-efficient perovskite solar cells(PSCs). To achieve a higher PSC performance, great efforts have been devoted to the growth of larger perovskite grains;however, how the gain size can influence the PSC performance in a working device remains unclear. Herein, using laser-scanned confocal microscopy coupled with a photocurrent detection module, we realize local photocurrent, photoluminescence(PL) intensity and PL lifetime mappings directly in a working PSC. For perovskite grains of various sizes(from ~500 nm to a few micrometers), their local photocurrent exhibit a statically positive correlation with the grain size, but anti-correlated with the grain’s local PL intensity. This result suggests that a larger perovskite grain likely has fewer defects and more importantly better interfacial contact with the charge collection layers and thus leads to higher charge collection efficiency, and the optimum grain size is found to be ≥2 μm.Our result provides important guidance to the growth and control of perovskite microstructures toward the further improvement of PSC performance.展开更多
The room-temperature(RT)bonding mechanisms of Ga As/Si O_(2)/Si and Ga As/Si heterointerfaces fabricated by surface-activated bonding(SAB)are investigated using a focused ion beam(FIB)system,cross-sectional scanning t...The room-temperature(RT)bonding mechanisms of Ga As/Si O_(2)/Si and Ga As/Si heterointerfaces fabricated by surface-activated bonding(SAB)are investigated using a focused ion beam(FIB)system,cross-sectional scanning transmission electron microscopy(TEM),energy dispersive x-ray spectroscopy(EDX)and scanning acoustic microscopy(SAM).According to the element distribution detected by TEM and EDX,it is found that an intermixing process occurs among different atoms at the heterointerface during the RT bonding process following the surface-activation treatment.The diffusion of atoms at the interface is enhanced by the point defects introduced by the process of surface activation.We can confirm that through the point defects,a strong heterointerface can be created at RT.The measured bonding energies of Ga As/Si O_(2)/Si and Ga As/Si wafers are 0.7 J/m^(2)and 0.6 J/m^(2).The surface-activation process can not only remove surface oxides and generate dangling bonds,but also enhance the atomic diffusivity at the interface.展开更多
Structured optical fields inside a waveguide possess the transverse spin, i.e., the spin angular momentum perpendicular to the direction of the waveguide. The physical origin of the transverse spin can be attributed t...Structured optical fields inside a waveguide possess the transverse spin, i.e., the spin angular momentum perpendicular to the direction of the waveguide. The physical origin of the transverse spin can be attributed to the presence of an effective rest mass of photons in guided waves, or equivalently, to the existence of a longitudinal field component, such that the transverse and longitudinal fields together form an elliptical polarization plane. In contrary to the traditional viewpoint, the transverse spin of photons in guided waves is also quantized, and its quantization form is related to the ellipticity of the polarization ellipse. The direction of the transverse spin depends on the propagation direction of electromagnetic waves along the waveguide, such a spin-momentum locking may have important applications in spin-dependent unidirectional optical interfaces. By means of a coupling between the transverse spin of guided waves and some physical degrees of freedom, one can develop an optical analogy of spintronics, i.e., spinoptics.展开更多
We have investigated the electronic and magnetic properties of zigzag phosphorene nanoribbons(ZPNRs)with transition metal(TM)passivated atoms,it can be found that the ZPNRs with TM passivated atoms exhibit different m...We have investigated the electronic and magnetic properties of zigzag phosphorene nanoribbons(ZPNRs)with transition metal(TM)passivated atoms,it can be found that the ZPNRs with TM passivated atoms exhibit different magnetisms except for the Ni-passivated system.Meanwhile,the results show that the magnetic moments of ZPNRs with TM passivated atoms are larger than that of ZPNRs with other passivated non-metals/groups.Interestingly,it can be found that Fe-passivated ZPNR exhibits magnetic semiconducting character,which provides the possbility for the application of phosphorene in information storage.For Mn-passivated ZPNRs,it exhibits the half-metallicity.These results may be useful for potential applications of phosphorene in electronic and high-performance spintronic devices.展开更多
Silicon-based carbon composites are believed as promising anodes in the near future due to their outstanding specific capacity and relatively lower volume effect compared to pure silicon anodes.Herein,a multilayer sph...Silicon-based carbon composites are believed as promising anodes in the near future due to their outstanding specific capacity and relatively lower volume effect compared to pure silicon anodes.Herein,a multilayer spherical core-shell(M-SCS)electrode with a graphite framework prepared with Si@O-MCMB/C nanoparticles is developed,which aims to realize chemically/mechanically stability during the lithiation/delithiation process with high specific capacity.An electrochemical-/mechanical-coupling model for the M-SCS structure is established with various chemical/mechanical boundary conditions.The simulation of finite difference method(FDM)has been conducted based on the proposed coupling model,by which the diffusion-induced stress along both the radial and the circumferential directions is determined.Moreover,factors that influence the diffusion-induced stress of the M-SCS structure have been discussed and analyzed in detail.展开更多
Integration of the cloud desktop and cloud storage platform is urgent for enterprises. However, current proposals for cloud disk are not satisfactory in terms of the decoupling of virtual computing and business data s...Integration of the cloud desktop and cloud storage platform is urgent for enterprises. However, current proposals for cloud disk are not satisfactory in terms of the decoupling of virtual computing and business data storage in the cloud desktop environment. In this paper, we present a new virtual disk mapping method for cloud desktop storage. In Windows, compared with virtual hard disk method of popular cloud disks, the proposed implementation of client based on the virtual disk driver and the file system filter driver is available for widespread desktop environments, especially for the cloud desktop with limited storage resources. Further more, our method supports customizable local cache storage, resulting in userfriendly experience for thinclients of the cloud desktop. The evaluation results show that our virtual disk mapping method performs well in the readwrite throughput of different scale files.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12272257,12102292,12032006)the special fund for Science and Technology Innovation Teams of Shanxi Province(Nos.202204051002006).
文摘This study employs a data-driven methodology that embeds the principle of dimensional invariance into an artificial neural network to automatically identify dominant dimensionless quantities in the penetration of rod projectiles into semi-infinite metal targets from experimental measurements.The derived mathematical expressions of dimensionless quantities are simplified by the examination of the exponent matrix and coupling relationships between feature variables.As a physics-based dimension reduction methodology,this way reduces high-dimensional parameter spaces to descriptions involving only a few physically interpretable dimensionless quantities in penetrating cases.Then the relative importance of various dimensionless feature variables on the penetration efficiencies for four impacting conditions is evaluated through feature selection engineering.The results indicate that the selected critical dimensionless feature variables by this synergistic method,without referring to the complex theoretical equations and aiding in the detailed knowledge of penetration mechanics,are in accordance with those reported in the reference.Lastly,the determined dimensionless quantities can be efficiently applied to conduct semi-empirical analysis for the specific penetrating case,and the reliability of regression functions is validated.
基金Project supported by the National Key R&D Program of China(Grant No.2017YFB0305800)
文摘The band structure, density of states, optical properties, carrier mobility, and loss function of graphene, black phosphorus（BP）, and molybdenum disulfide（MoS_2） were investigated by the first-principles method with the generalized-gradient approximation. The graphene was a zero-band-gap semiconductor. The band gaps of BP and MoS_2 were strongly dependent on the number of layers. The relationships between layers and band gap were built to predict the band gap of few-layer BP and MoS_2. The absorption showed an explicit anisotropy for light polarized in（1 0 0） and（0 0 1） directions of graphene, BP,and MoS_2. This behavior may be readily detected in spectroscopic measurements and exploited for optoelectronic applications. Moreover, graphene（5.27 × 10~4 cm^2·V^（-1）·s^（-1））, BP（1.5 × 10~4 cm^2·V^（-1）·s^（-1））, and MoS_2（2.57×102 cm2·V-1·s-1）have high carrier mobility. These results show that graphene, BP, and MoS_2 are promising candidates for future electronic applications.
基金financially supported by the National Key Research and Development Program of China (2022YFE0206300)the National Natural Science Foundation of China (U21A2081,22075074, 22209047)+1 种基金Outstanding Young Scientists Research Funds from Hunan Province (2020JJ2004)Major Science and Technology Program of Hunan Province (2020WK2013)。
文摘Prussian blue analogues(PBAs) are considered as superior cathode materials for potassium-ion batteries(PIBs) because of their three-dimensional open framework structure,high stability,and low cost.However,the intrinsic lattice defects and low potassium content typically results in poor rate and cycling performance,thus limited their practical applications.In this work,high-quality K1.64FeFe(CN)6(PW-HQ)material with less crystalline water(6.21%) and high potassium content(1.64 mol^(-1)) was successfully synthesized by a novel coprecipitation method with potassium citrate(K-CA) and potassium chloride(KCl) addition.Specifically,the electrode delivers a reversible capacity of 113.1 mA h g^(-1)at the current rate of 50 mA g^(-1)with~100% coulombic efficiency.Besides,the electrode retained 90% reversible capacity at 500 mA g^(-1)current density after 1000 cycles,indicating only 0.01% capacity decay per cycle.Moreover,we have revealed that the introduction of K-CA controlled the chelating rate of Fe(Ⅱ) and the addition of KCl increased the K+content,hence improving the capacity and stability of the asprepared electrodes.Structural evolution and potassium storage mechanism were further investigated by detailed ex-situ X-ray diffraction and in-situ Raman measurements,which demonstrated reversible potassiation/depotassiation behavior and negligible volume change during the electrochemical process.In general,this work provides an efficient strategy to eliminate water contents in Prussian blue cathode and improve its electrochemical performance,which plays a key role in promoting the industrialization of potassium ion batteries.
基金the funding support from the MOST(2018YFA0208704,2016YFA0200602)NSFC(21725305)+6 种基金funding support from the NSFC(22073099,U2001216)funding support from the NSFC(51773025,22109019)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB17010100)the Youth Innovation Promotion Association CAS(2019188)the Dalian Youth Science and Technology Star Project Support Program(2019RQ0105)the DICP funding(DICP I201913)funding support from the Science Research Project of Liaoning Province in China under Grant Nos.LF2020003。
文摘Developing an interplay between the local morphological character and its local photovoltaic(PV)parameters in a perovskite thin film is essential for guiding the construction of highly-efficient perovskite solar cells(PSCs). To achieve a higher PSC performance, great efforts have been devoted to the growth of larger perovskite grains;however, how the gain size can influence the PSC performance in a working device remains unclear. Herein, using laser-scanned confocal microscopy coupled with a photocurrent detection module, we realize local photocurrent, photoluminescence(PL) intensity and PL lifetime mappings directly in a working PSC. For perovskite grains of various sizes(from ~500 nm to a few micrometers), their local photocurrent exhibit a statically positive correlation with the grain size, but anti-correlated with the grain’s local PL intensity. This result suggests that a larger perovskite grain likely has fewer defects and more importantly better interfacial contact with the charge collection layers and thus leads to higher charge collection efficiency, and the optimum grain size is found to be ≥2 μm.Our result provides important guidance to the growth and control of perovskite microstructures toward the further improvement of PSC performance.
基金the National Natural Science Foundation of China(Grant Nos.61505003 and 61674140)the Beijing Education Commission Project(Grant No.SQKM201610005008)Beijing Postdoctoral Research Foundation(Grant No.2020-Z2-043)。
文摘The room-temperature(RT)bonding mechanisms of Ga As/Si O_(2)/Si and Ga As/Si heterointerfaces fabricated by surface-activated bonding(SAB)are investigated using a focused ion beam(FIB)system,cross-sectional scanning transmission electron microscopy(TEM),energy dispersive x-ray spectroscopy(EDX)and scanning acoustic microscopy(SAM).According to the element distribution detected by TEM and EDX,it is found that an intermixing process occurs among different atoms at the heterointerface during the RT bonding process following the surface-activation treatment.The diffusion of atoms at the interface is enhanced by the point defects introduced by the process of surface activation.We can confirm that through the point defects,a strong heterointerface can be created at RT.The measured bonding energies of Ga As/Si O_(2)/Si and Ga As/Si wafers are 0.7 J/m^(2)and 0.6 J/m^(2).The surface-activation process can not only remove surface oxides and generate dangling bonds,but also enhance the atomic diffusivity at the interface.
基金Project supported by the 2021 Innovation capability enhancement project of small and medium-sized technologybased enterprises in Shandong Province of China (Grant No. 2021TSGC1043)。
文摘Structured optical fields inside a waveguide possess the transverse spin, i.e., the spin angular momentum perpendicular to the direction of the waveguide. The physical origin of the transverse spin can be attributed to the presence of an effective rest mass of photons in guided waves, or equivalently, to the existence of a longitudinal field component, such that the transverse and longitudinal fields together form an elliptical polarization plane. In contrary to the traditional viewpoint, the transverse spin of photons in guided waves is also quantized, and its quantization form is related to the ellipticity of the polarization ellipse. The direction of the transverse spin depends on the propagation direction of electromagnetic waves along the waveguide, such a spin-momentum locking may have important applications in spin-dependent unidirectional optical interfaces. By means of a coupling between the transverse spin of guided waves and some physical degrees of freedom, one can develop an optical analogy of spintronics, i.e., spinoptics.
基金Project supported by the National Natural Science Foundation of China(Grant No.11564008)the Natural Science Foundation of Guangxi Zhuang Autonomous Region,China(Grant No.2017GXNSFAA198195)the Shanghai Supercomputer Center。
文摘We have investigated the electronic and magnetic properties of zigzag phosphorene nanoribbons(ZPNRs)with transition metal(TM)passivated atoms,it can be found that the ZPNRs with TM passivated atoms exhibit different magnetisms except for the Ni-passivated system.Meanwhile,the results show that the magnetic moments of ZPNRs with TM passivated atoms are larger than that of ZPNRs with other passivated non-metals/groups.Interestingly,it can be found that Fe-passivated ZPNR exhibits magnetic semiconducting character,which provides the possbility for the application of phosphorene in information storage.For Mn-passivated ZPNRs,it exhibits the half-metallicity.These results may be useful for potential applications of phosphorene in electronic and high-performance spintronic devices.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12072229 and 11602167).
文摘Silicon-based carbon composites are believed as promising anodes in the near future due to their outstanding specific capacity and relatively lower volume effect compared to pure silicon anodes.Herein,a multilayer spherical core-shell(M-SCS)electrode with a graphite framework prepared with Si@O-MCMB/C nanoparticles is developed,which aims to realize chemically/mechanically stability during the lithiation/delithiation process with high specific capacity.An electrochemical-/mechanical-coupling model for the M-SCS structure is established with various chemical/mechanical boundary conditions.The simulation of finite difference method(FDM)has been conducted based on the proposed coupling model,by which the diffusion-induced stress along both the radial and the circumferential directions is determined.Moreover,factors that influence the diffusion-induced stress of the M-SCS structure have been discussed and analyzed in detail.
基金key technologies of the integration of cloud desktop and cloud storage Platform is supported by ZTE Industry-Academia-Research Cooperation Funds
文摘Integration of the cloud desktop and cloud storage platform is urgent for enterprises. However, current proposals for cloud disk are not satisfactory in terms of the decoupling of virtual computing and business data storage in the cloud desktop environment. In this paper, we present a new virtual disk mapping method for cloud desktop storage. In Windows, compared with virtual hard disk method of popular cloud disks, the proposed implementation of client based on the virtual disk driver and the file system filter driver is available for widespread desktop environments, especially for the cloud desktop with limited storage resources. Further more, our method supports customizable local cache storage, resulting in userfriendly experience for thinclients of the cloud desktop. The evaluation results show that our virtual disk mapping method performs well in the readwrite throughput of different scale files.
