The physicochemical properties of SUS304 foil surfaces are crucial to their applications.Pulsed laser modification was applied to 30μm thick SUS304 foils to systematically investigate the influence of laser energy on...The physicochemical properties of SUS304 foil surfaces are crucial to their applications.Pulsed laser modification was applied to 30μm thick SUS304 foils to systematically investigate the influence of laser energy on surface characteristics.Through multidimensional characterization of surface morphology,three-dimensional profiles and roughness,contact angle,and chemical composition,the structure-function correlation between laser energy and the physicochemical properties of steel surface was revealed.With increasing laser energy,the surface morphology of the steel transitions from a directional rolling-marked structure to a uniform sponge-like isotropic structure,accompanied by increased peak density and an expanded interfacial area.Additionally,the chemical state on the metal surface gradually stabilizes from unstable redox reactions,forming a stable oxide layer and significantly increasing active hydroxyl groups,thereby effectively improving surface wettability.Single lap shear tests reveal an enhancement in the bonding strength of steel/carbon fiber reinforced composites joints after laser modification,which is attributed to the synergistic effects of mechanical interlocking,enhanced wettability,and chemical bonding at the interface.The demonstrated potential of laser surface treatment for modifying SUS304 ultra-thin foils provides theoretical support and technical reference for its application in fiber metal laminates.展开更多
A novel substrate integrated microstrip to ultra-thin cavity filter transition operating in the W-band is proposed in this letter.The structure is a new method of connecting microstrip circuits and waveguide filters,a...A novel substrate integrated microstrip to ultra-thin cavity filter transition operating in the W-band is proposed in this letter.The structure is a new method of connecting microstrip circuits and waveguide filters,and this new structure enables a planar integrated transition from microstrip lines to ultra-thin cavity filters,thereby reducing the size of the transition structure and achieving miniaturization.The structure includes a conventional tapered microstrip transition structure,which guides the electromagnetic field from the microstrip line to the reduced-height dielectric-filled waveguide,and an air-filled matching cavity which is placed between the dielectric-filled waveguide and the ultra-thin cavity filter.The heights of the microstrip line,the dielectric-filled waveguide and the ultra-thin cavity filter are the same,enabling seamless integration within a planar radio-frequency(RF)circuit.To facilitate testing,mature finline transition structures are integrated at both ends of the microstrip line during fabrications.The simulation results of the fabricated microstrip to ultra-thin cavity filter transition with the finline transition structure,with a passband of 91.5-96.5 GHz,has an insertion loss of less than 1.9 dB and a return loss lower than-20 dB.And the whole structure has also been measured which achieves an insertion loss less than 2.6 dB and a return loss lower than-15 dB within the filter's passband,including the additional insertion loss introduced by the finline transitions.Finally,a W-band compact up-conversion module is designed,and the test results show that after using the proposed structure,the module achieves 95 dBc suppression of the 84 GHz local oscillator.It is also demonstrated that the structure proposed in this letter achieves miniaturization of the system integration without compromising the filter performance.展开更多
The equimolar NbZrTi medium-entropy alloy(MEA)has attracted attention due to its excellent comprehensive mechanical properties.In this study,the designed body-centered cubic NbZrTiAl_(4)(atomic percent,at%)MEA by Al a...The equimolar NbZrTi medium-entropy alloy(MEA)has attracted attention due to its excellent comprehensive mechanical properties.In this study,the designed body-centered cubic NbZrTiAl_(4)(atomic percent,at%)MEA by Al addition,having a superplastic extensibility of~5000%under cold rolling,enables directly fabricated ultrathin foils with a thickness down to~0.2 mm without any treatments.Particularly,the annealed NbZrTiAl_(4) MEA foils,containing a coherent nanoscale B2,exhibit an ultrahigh yield strength of up to~1130 MPa,which even surpasses the bulk counterpart,while maintaining a good fracture elongation of up to~14%.The Al addition induced a stronger solid solution strengthening and fine-grain strengthening in the foils.Complex dislocation interactions and dislocation–B2 interactions promoted a dynamical formation of dislocation bands,which yielded work-hardening ability and tensile ductility.These findings provide a novel strategy for the design of ultrathin refractory medium-entropy foils to break through their performance limits at ultrahigh temperatures and guide the design of high-performance lightweight foils for structural applications.展开更多
The textured roll and polished roll were applied instead of the ground roll in a 20-high mill to conduct two-pass rolling of 316L stainless steel strip with thickness of 0.027 mm.After the two-pass rolling with the te...The textured roll and polished roll were applied instead of the ground roll in a 20-high mill to conduct two-pass rolling of 316L stainless steel strip with thickness of 0.027 mm.After the two-pass rolling with the textured roll and polished roll(TPR),the surface roughness of the strip is dramatically reduced,and the surface topographical anisotropy index is diminished to 30.9%of the initial strip.Comparing with the strip rolled using the ground roll in both passes(GGR),the elongation of TPR rolled strip is obviously improved,and the mechanical property anisotropy is greatly weakened.The anisotropy index of tensile strength and elongation are 42.58%and 52.59%of that of GGR rolled strip,which is mainly attributed to the significant decrease of the texture intensity of the strip by TPR process.The results indicate that TPR process can obtain the stainless steel ultra-thin strip with smooth and uniform surface topography and good mechanical properties.展开更多
Rechargeable magnesium batteries(RMBs)have attracted much attention due to the high theoretical capacity(3833 mAh cm−3)of magnesium metal negative electrode and abundant resources.However,the preparation of ultra-thin...Rechargeable magnesium batteries(RMBs)have attracted much attention due to the high theoretical capacity(3833 mAh cm−3)of magnesium metal negative electrode and abundant resources.However,the preparation of ultra-thin magnesium foils faces the problems of rolling difficulty and high processing cost,while the use of thick magnesium foils leads to low utilization of magnesium and reduces the energy density.To tackle the above problems,we successfully prepared ultra-thin magnesium foils based on electrolytic process and investigated the effect of different substrates.The magnesium foils prepared using Mo substrate have more uniform surface morphology and lower surface roughness,which is attributed to the lower magnesium nucleation overpotential of Mo substrate.Meanwhile,density functional theory calculations show that the adsorption energy of Mo on Mg is more negative,which is conducive to achieving uniform nucleation and deposition of Mg.The Mg deposition on Mo substrate undergoes the characteristic stages of transient nucleation,nucleus accretion,multidirectional heterotopic growth,and columnar crystal stacking,and ultimately the formation of a dense deposited layer.In addition,the prepared ultra-thin Mg foil with Mo substrate can stably cycle for 1000 h at 3 mA cm^(-2) with high utilization of 50% in the symmetric cell.This study develops a facile method for the preparation of ultra-thin Mg foils,which opens up a new path for developing high-performance ultra-thin negative electrodes for RMBs.展开更多
Modulating the interface between the electron transport layer(ETL)and perovskite to minimize interfacial recombination is pivotal for developing efficient and stable perovskite solar cells.Here,we introduce an ultra-t...Modulating the interface between the electron transport layer(ETL)and perovskite to minimize interfacial recombination is pivotal for developing efficient and stable perovskite solar cells.Here,we introduce an ultra-thin ZrO_(2)insulating interface layer onto the inner surface of the mesoporous TiO_(2)ETL via the chemical bath deposition in the zirconium n-butoxide solution,which alters the interface characteristics between TiO_(2)and perovskite for the printable hole-conductor-free mesoscopic perovskite solar cells(p-MPSCs).The insulating ZrO_(2)interface layer reduces interface defects and suppresses interfacial non-radiative recombination.Furthermore,the ZrO_(2)interface layer improves the wettability of the mesoporous TiO_(2)ETL,which favors the crystallization of perovskite within the mesoporous scaffold.Meanwhile,the device performance presents thickness dependence on the interface layer.While increased thickness improves the open-circuit voltage,excessive thickness negatively impacts both the short-circuit current density and fill factor.Consequently,an improved power conversion efficiency of 19.9% was achieved for p-MPSCs with the ZrO_(2)interface layer at its optimized thickness.展开更多
A novel mesa ultra-thin base AlGaAs/GaAs HBT is designed and fabricated with wet chemical selective etch technique and monitor electrode technique. It has a particular and obvious voltage-controlled NDR whose PVCR is ...A novel mesa ultra-thin base AlGaAs/GaAs HBT is designed and fabricated with wet chemical selective etch technique and monitor electrode technique. It has a particular and obvious voltage-controlled NDR whose PVCR is larger than 120. By use of device simulation,the cause of NDR is that increasing collector voltage makes the ultrathin base reach through and the device transforms from a bipolar state to a bulk barrier state. In addition, the simulated cutoff frequency is about 60-80GHz.展开更多
In many fields of high-tech industry the ultra-t hi n wall parts are employed. In this paper the experiments were carried out to dis cuss the surface microstructure of the camera’s guided drawtube by applying ult ras...In many fields of high-tech industry the ultra-t hi n wall parts are employed. In this paper the experiments were carried out to dis cuss the surface microstructure of the camera’s guided drawtube by applying ult rasonic vibration cutting device to the traditional lathe. The influence rule of the cutting condition on the surface roughness was put forward, which was drawn by comparing the ultrasonic cutting with the common cutting by use of the cemen ted carbide tool and the polycrystalline diamond (PCD) tool. The test results sh owed that the ultrasonic cutting performs better than the common cutting in the same condition. According to the test results analyzing, the surface characteriz ation is influenced clearly by the rigidity of the acoustic system and the machi ne tool, as well the setting height of the tool tip. Otherwise, the dense regula r low frequency vibration ripples will be scraped on the machined surface. When the tool tip is set higher than the rotating center of the work piece by three t imes of the amplitude of ultrasonic vibration, the vibration ripples behave alig ht; they turn light and shade alternatively when the tool tip is lower than the rotating center of the work piece by three times of the amplitude of ultrasonic vibration. According to the test result analyzing, the following conclusions are put forward: 1) The surface roughness in ultrasonic cutting is better than that in common cutting. Under a one third critical cutting velocity, the value of th e surface roughness in ultrasonic cutting rise slightly along with the cutting v elocity, while in common cutting it decreases contrast to the cutting velocity; the curves of the surface roughness in ultrasonic cutting and common cutting see m to be alike, both increase along with the feed rate and the cutting depth, but the value in ultrasonic cutting is smaller in the same condition.2) The influen ce of the coolant on the surface roughness cannot be ignored. The kerosene can b e employed to improve the surface roughness in ultrasonic machining.3) In ultras onic cutting process of aluminum alloy ultra-thin wall work piece, the PCD tool performs better than the cemented carbide tools.4) The vibration ripples result from the not enough rigidity of the acoustic system and the improper setting he ight of the tool tip. The departure of the tool tip from the rotating center of the work piece to some extent causes the vibration ripples on the machined surfa ce.展开更多
In this study, high- and low-grade grain-oriented electrical steels were used as the initial materials to produce 0.08-mm-thick sheet with one-step cold-rolling method. Electron backscattering diffraction analysis tec...In this study, high- and low-grade grain-oriented electrical steels were used as the initial materials to produce 0.08-mm-thick sheet with one-step cold-rolling method. Electron backscattering diffraction analysis technique and X-ray diffraction texture analysis technique were adopted to investigate the effect of initial Goss texture sharpness on texture evolution and magnetic properties of ultra-thin grain-oriented electrical steel. The results showed that primary recrystal- lization and secondary recrystallization were the main processes that occurred during annealing. The induced factors for secondary recrystallization of two grades samples were not Consistent. The high-grade samples presented texture induction mechanism, while the low-grade samples revealed strong surface-energy induction mechanism. The initial Goss texture sharpness had a great impact on texture evolution and magnetic properties of ultra-thin grain-oriented electrical steel. The Goss texture component formed after primary recrystallization was stronger, and better magnetic properties were obtained at low frequencies. For low-grade samples, secondary recrystallization enhanced the intensity of Goss texture, and both grain size and texture contributed to better high-frequency magnetic properties after secondary recrystallization. By controlling the annealing process, the magnetic properties of low-grade products could be significantly improved, thus achieving conversion from low-grade to high-grade products.展开更多
In recent years,Cu_(2)ZnSnS_(4)(CZTS)semiconductor materials have received intensive attention in the field of thin-film solar cells owing to its non-toxic and low-cost elements.In this work,double-pressure sputtering...In recent years,Cu_(2)ZnSnS_(4)(CZTS)semiconductor materials have received intensive attention in the field of thin-film solar cells owing to its non-toxic and low-cost elements.In this work,double-pressure sputtering technology is applied to obtain highly efficient and ultra-thin(-450 nm)pure Cu_(2)ZnSnS_(4)(CZTS)solar cell.Using mixed materials with sulfides and copper powder as a quaternary target via spark plasma sintering(SPS)method and adopting double-layer sputtering(high+low pressure),a highly adhesive and large-grained CZTS thin film is achieved.As a result,the damage to the surface of Mo contact is decreased so that the reflectivity of incident light can be improved.Moreover,the composition of CZTS film was more uniform and the secondary phase separation at the Mo interface was reduced.Therefore,the interface defect state and deep level defect density in corresponding device with double-pressure is reduced and the ratio of depletion thickness to absorption layer thickness can reached to 0.58,which promoted the collection of photogenerated carriers.Finally,an efficiency of 9.3%for ultra-thin(~450 nm)CZTS film solar cell is obtained.展开更多
Electrochemical behaviour and passive film characteristics of an ultra-thin 316 L foil with a thickness of20μm in 3.5 wt.%NaCl solution were investigated using multiple techniques,focusing on the effect of microstruc...Electrochemical behaviour and passive film characteristics of an ultra-thin 316 L foil with a thickness of20μm in 3.5 wt.%NaCl solution were investigated using multiple techniques,focusing on the effect of microstructure,the applied potential,and the pH of the solution.The microstructure contains mainly fine grains(~4μm)with high-angle boundaries and preferential orientation of(220),and no MnS inclusion was detected.The electrochemical measurements show a significantly higher breakdown potential and lower passive current density for the 316 L foil than traditional wrought 316 L.The surface analyses using angle-resolved X-ray photoelectron spectroscopy(ARXPS)and time-of-flight secondary ion mass spectroscopy(TOF-SIMS)reveal that,compared to the wrought material,both the inner and out parts of the passive film on the 316 L foil are more enriched in Cr-and Mo-oxides.The microstructure favourable for elemental diffusion and the absence of MnS inclusion facilitate the formation of a continuous compact Cr-and Mo-rich passive film,which effectively retards corrosion in NaCl solution and remains stable in acidic solution(pH 2)or at high polarised potential up to 600 mV vs Ag/AgCl.展开更多
Monte Carlo simulations reveal considerable straggling of energy loss by the same ions with the same energy in fully-depleted silicon-on-insulator （FDSOI） devices with ultra-thin sensitive silicon layers down to 2.5...Monte Carlo simulations reveal considerable straggling of energy loss by the same ions with the same energy in fully-depleted silicon-on-insulator （FDSOI） devices with ultra-thin sensitive silicon layers down to 2.5 rim. The absolute straggling of deposited energy decreases with decreasing thickness of the active silicon layer. While the relative straggling increases gradually with decreasing thickness of silicon films and exhibits a sharp rise as the thickness of the silicon film descends below a threshold value of 50 nm, with the dispersion of deposited energy ascending above ~10%. Ion species and energy dependence of the energy-loss straggling are also investigated. For a given beam, the dispersion of deposited energy results in large uncertainty on the actual linear energy transfer （LET） of incident ions, and thus single event effect （SEE） responses, which pose great challenges for traditional error rate prediction methods.展开更多
基金supported by Major Program of National Natural Science Foundation of China(U22A20188)National Science Fund for Distinguished Young Scholars(52425504).
文摘The physicochemical properties of SUS304 foil surfaces are crucial to their applications.Pulsed laser modification was applied to 30μm thick SUS304 foils to systematically investigate the influence of laser energy on surface characteristics.Through multidimensional characterization of surface morphology,three-dimensional profiles and roughness,contact angle,and chemical composition,the structure-function correlation between laser energy and the physicochemical properties of steel surface was revealed.With increasing laser energy,the surface morphology of the steel transitions from a directional rolling-marked structure to a uniform sponge-like isotropic structure,accompanied by increased peak density and an expanded interfacial area.Additionally,the chemical state on the metal surface gradually stabilizes from unstable redox reactions,forming a stable oxide layer and significantly increasing active hydroxyl groups,thereby effectively improving surface wettability.Single lap shear tests reveal an enhancement in the bonding strength of steel/carbon fiber reinforced composites joints after laser modification,which is attributed to the synergistic effects of mechanical interlocking,enhanced wettability,and chemical bonding at the interface.The demonstrated potential of laser surface treatment for modifying SUS304 ultra-thin foils provides theoretical support and technical reference for its application in fiber metal laminates.
基金Supported by the Fundamental Research Funds for the Central Universities(ZYGX2021J008)。
文摘A novel substrate integrated microstrip to ultra-thin cavity filter transition operating in the W-band is proposed in this letter.The structure is a new method of connecting microstrip circuits and waveguide filters,and this new structure enables a planar integrated transition from microstrip lines to ultra-thin cavity filters,thereby reducing the size of the transition structure and achieving miniaturization.The structure includes a conventional tapered microstrip transition structure,which guides the electromagnetic field from the microstrip line to the reduced-height dielectric-filled waveguide,and an air-filled matching cavity which is placed between the dielectric-filled waveguide and the ultra-thin cavity filter.The heights of the microstrip line,the dielectric-filled waveguide and the ultra-thin cavity filter are the same,enabling seamless integration within a planar radio-frequency(RF)circuit.To facilitate testing,mature finline transition structures are integrated at both ends of the microstrip line during fabrications.The simulation results of the fabricated microstrip to ultra-thin cavity filter transition with the finline transition structure,with a passband of 91.5-96.5 GHz,has an insertion loss of less than 1.9 dB and a return loss lower than-20 dB.And the whole structure has also been measured which achieves an insertion loss less than 2.6 dB and a return loss lower than-15 dB within the filter's passband,including the additional insertion loss introduced by the finline transitions.Finally,a W-band compact up-conversion module is designed,and the test results show that after using the proposed structure,the module achieves 95 dBc suppression of the 84 GHz local oscillator.It is also demonstrated that the structure proposed in this letter achieves miniaturization of the system integration without compromising the filter performance.
基金funded by the Youth Fund Project of GRINM(No.66922309)the National Natural Science Foundation of China(No.52301220)。
文摘The equimolar NbZrTi medium-entropy alloy(MEA)has attracted attention due to its excellent comprehensive mechanical properties.In this study,the designed body-centered cubic NbZrTiAl_(4)(atomic percent,at%)MEA by Al addition,having a superplastic extensibility of~5000%under cold rolling,enables directly fabricated ultrathin foils with a thickness down to~0.2 mm without any treatments.Particularly,the annealed NbZrTiAl_(4) MEA foils,containing a coherent nanoscale B2,exhibit an ultrahigh yield strength of up to~1130 MPa,which even surpasses the bulk counterpart,while maintaining a good fracture elongation of up to~14%.The Al addition induced a stronger solid solution strengthening and fine-grain strengthening in the foils.Complex dislocation interactions and dislocation–B2 interactions promoted a dynamical formation of dislocation bands,which yielded work-hardening ability and tensile ductility.These findings provide a novel strategy for the design of ultrathin refractory medium-entropy foils to break through their performance limits at ultrahigh temperatures and guide the design of high-performance lightweight foils for structural applications.
基金supported by the National Natural Science Foundation of China(Nos.51974196,52275361,and 52305406)the Key Projects of the National Natural Science Foundation of China(No.U22A20188)the Special Projects of the Central Government in Guidance of Local Science and Technology Development(YDZX20191400002149).
文摘The textured roll and polished roll were applied instead of the ground roll in a 20-high mill to conduct two-pass rolling of 316L stainless steel strip with thickness of 0.027 mm.After the two-pass rolling with the textured roll and polished roll(TPR),the surface roughness of the strip is dramatically reduced,and the surface topographical anisotropy index is diminished to 30.9%of the initial strip.Comparing with the strip rolled using the ground roll in both passes(GGR),the elongation of TPR rolled strip is obviously improved,and the mechanical property anisotropy is greatly weakened.The anisotropy index of tensile strength and elongation are 42.58%and 52.59%of that of GGR rolled strip,which is mainly attributed to the significant decrease of the texture intensity of the strip by TPR process.The results indicate that TPR process can obtain the stainless steel ultra-thin strip with smooth and uniform surface topography and good mechanical properties.
基金supported by the National Natural Science Foundation of China(No.U2037601)the National Key Research and Development Program(No.2023YFB3809500)the Chongqing Technology Innovation and Application Development Project(No.CSTB2022TIAD-KPX0028).
文摘Rechargeable magnesium batteries(RMBs)have attracted much attention due to the high theoretical capacity(3833 mAh cm−3)of magnesium metal negative electrode and abundant resources.However,the preparation of ultra-thin magnesium foils faces the problems of rolling difficulty and high processing cost,while the use of thick magnesium foils leads to low utilization of magnesium and reduces the energy density.To tackle the above problems,we successfully prepared ultra-thin magnesium foils based on electrolytic process and investigated the effect of different substrates.The magnesium foils prepared using Mo substrate have more uniform surface morphology and lower surface roughness,which is attributed to the lower magnesium nucleation overpotential of Mo substrate.Meanwhile,density functional theory calculations show that the adsorption energy of Mo on Mg is more negative,which is conducive to achieving uniform nucleation and deposition of Mg.The Mg deposition on Mo substrate undergoes the characteristic stages of transient nucleation,nucleus accretion,multidirectional heterotopic growth,and columnar crystal stacking,and ultimately the formation of a dense deposited layer.In addition,the prepared ultra-thin Mg foil with Mo substrate can stably cycle for 1000 h at 3 mA cm^(-2) with high utilization of 50% in the symmetric cell.This study develops a facile method for the preparation of ultra-thin Mg foils,which opens up a new path for developing high-performance ultra-thin negative electrodes for RMBs.
基金financial support from the National Natural Science Foundation of China(22439001,52172198,51902117)supported by the Innovation Fund of Wuhan National Laboratory for Optoelectronicsthe Analytical and Testing Center of Huazhong University of Science and Technology(HUST)for performing various characterizations。
文摘Modulating the interface between the electron transport layer(ETL)and perovskite to minimize interfacial recombination is pivotal for developing efficient and stable perovskite solar cells.Here,we introduce an ultra-thin ZrO_(2)insulating interface layer onto the inner surface of the mesoporous TiO_(2)ETL via the chemical bath deposition in the zirconium n-butoxide solution,which alters the interface characteristics between TiO_(2)and perovskite for the printable hole-conductor-free mesoscopic perovskite solar cells(p-MPSCs).The insulating ZrO_(2)interface layer reduces interface defects and suppresses interfacial non-radiative recombination.Furthermore,the ZrO_(2)interface layer improves the wettability of the mesoporous TiO_(2)ETL,which favors the crystallization of perovskite within the mesoporous scaffold.Meanwhile,the device performance presents thickness dependence on the interface layer.While increased thickness improves the open-circuit voltage,excessive thickness negatively impacts both the short-circuit current density and fill factor.Consequently,an improved power conversion efficiency of 19.9% was achieved for p-MPSCs with the ZrO_(2)interface layer at its optimized thickness.
文摘A novel mesa ultra-thin base AlGaAs/GaAs HBT is designed and fabricated with wet chemical selective etch technique and monitor electrode technique. It has a particular and obvious voltage-controlled NDR whose PVCR is larger than 120. By use of device simulation,the cause of NDR is that increasing collector voltage makes the ultrathin base reach through and the device transforms from a bipolar state to a bulk barrier state. In addition, the simulated cutoff frequency is about 60-80GHz.
文摘In many fields of high-tech industry the ultra-t hi n wall parts are employed. In this paper the experiments were carried out to dis cuss the surface microstructure of the camera’s guided drawtube by applying ult rasonic vibration cutting device to the traditional lathe. The influence rule of the cutting condition on the surface roughness was put forward, which was drawn by comparing the ultrasonic cutting with the common cutting by use of the cemen ted carbide tool and the polycrystalline diamond (PCD) tool. The test results sh owed that the ultrasonic cutting performs better than the common cutting in the same condition. According to the test results analyzing, the surface characteriz ation is influenced clearly by the rigidity of the acoustic system and the machi ne tool, as well the setting height of the tool tip. Otherwise, the dense regula r low frequency vibration ripples will be scraped on the machined surface. When the tool tip is set higher than the rotating center of the work piece by three t imes of the amplitude of ultrasonic vibration, the vibration ripples behave alig ht; they turn light and shade alternatively when the tool tip is lower than the rotating center of the work piece by three times of the amplitude of ultrasonic vibration. According to the test result analyzing, the following conclusions are put forward: 1) The surface roughness in ultrasonic cutting is better than that in common cutting. Under a one third critical cutting velocity, the value of th e surface roughness in ultrasonic cutting rise slightly along with the cutting v elocity, while in common cutting it decreases contrast to the cutting velocity; the curves of the surface roughness in ultrasonic cutting and common cutting see m to be alike, both increase along with the feed rate and the cutting depth, but the value in ultrasonic cutting is smaller in the same condition.2) The influen ce of the coolant on the surface roughness cannot be ignored. The kerosene can b e employed to improve the surface roughness in ultrasonic machining.3) In ultras onic cutting process of aluminum alloy ultra-thin wall work piece, the PCD tool performs better than the cemented carbide tools.4) The vibration ripples result from the not enough rigidity of the acoustic system and the improper setting he ight of the tool tip. The departure of the tool tip from the rotating center of the work piece to some extent causes the vibration ripples on the machined surfa ce.
基金financially supported by the National High Technology Research and Development Program of China(Grant No.2012AA03A505)
文摘In this study, high- and low-grade grain-oriented electrical steels were used as the initial materials to produce 0.08-mm-thick sheet with one-step cold-rolling method. Electron backscattering diffraction analysis technique and X-ray diffraction texture analysis technique were adopted to investigate the effect of initial Goss texture sharpness on texture evolution and magnetic properties of ultra-thin grain-oriented electrical steel. The results showed that primary recrystal- lization and secondary recrystallization were the main processes that occurred during annealing. The induced factors for secondary recrystallization of two grades samples were not Consistent. The high-grade samples presented texture induction mechanism, while the low-grade samples revealed strong surface-energy induction mechanism. The initial Goss texture sharpness had a great impact on texture evolution and magnetic properties of ultra-thin grain-oriented electrical steel. The Goss texture component formed after primary recrystallization was stronger, and better magnetic properties were obtained at low frequencies. For low-grade samples, secondary recrystallization enhanced the intensity of Goss texture, and both grain size and texture contributed to better high-frequency magnetic properties after secondary recrystallization. By controlling the annealing process, the magnetic properties of low-grade products could be significantly improved, thus achieving conversion from low-grade to high-grade products.
基金supported by the National Key R&D Program of China(No.2018YFE0203400)the Science and Technology plan project of Shenzhen(JCYJ20190808120001755)+1 种基金the National Natural Science Foundation of China(No.62074102)the Key Project of Department of Education of Guangdong Province(No.2018KZDXM059)China。
文摘In recent years,Cu_(2)ZnSnS_(4)(CZTS)semiconductor materials have received intensive attention in the field of thin-film solar cells owing to its non-toxic and low-cost elements.In this work,double-pressure sputtering technology is applied to obtain highly efficient and ultra-thin(-450 nm)pure Cu_(2)ZnSnS_(4)(CZTS)solar cell.Using mixed materials with sulfides and copper powder as a quaternary target via spark plasma sintering(SPS)method and adopting double-layer sputtering(high+low pressure),a highly adhesive and large-grained CZTS thin film is achieved.As a result,the damage to the surface of Mo contact is decreased so that the reflectivity of incident light can be improved.Moreover,the composition of CZTS film was more uniform and the secondary phase separation at the Mo interface was reduced.Therefore,the interface defect state and deep level defect density in corresponding device with double-pressure is reduced and the ratio of depletion thickness to absorption layer thickness can reached to 0.58,which promoted the collection of photogenerated carriers.Finally,an efficiency of 9.3%for ultra-thin(~450 nm)CZTS film solar cell is obtained.
基金the National Natural Science Foundation of China(No.5210010403)the China Postdoctoral Science Foundation(No.2021M690345)the Swedish Foundation for International Cooperation in Research and Higher Education(STINT project for Swedish-China collaboration,No.CH2017-7255)。
文摘Electrochemical behaviour and passive film characteristics of an ultra-thin 316 L foil with a thickness of20μm in 3.5 wt.%NaCl solution were investigated using multiple techniques,focusing on the effect of microstructure,the applied potential,and the pH of the solution.The microstructure contains mainly fine grains(~4μm)with high-angle boundaries and preferential orientation of(220),and no MnS inclusion was detected.The electrochemical measurements show a significantly higher breakdown potential and lower passive current density for the 316 L foil than traditional wrought 316 L.The surface analyses using angle-resolved X-ray photoelectron spectroscopy(ARXPS)and time-of-flight secondary ion mass spectroscopy(TOF-SIMS)reveal that,compared to the wrought material,both the inner and out parts of the passive film on the 316 L foil are more enriched in Cr-and Mo-oxides.The microstructure favourable for elemental diffusion and the absence of MnS inclusion facilitate the formation of a continuous compact Cr-and Mo-rich passive film,which effectively retards corrosion in NaCl solution and remains stable in acidic solution(pH 2)or at high polarised potential up to 600 mV vs Ag/AgCl.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11179003 and 10975164)
文摘Monte Carlo simulations reveal considerable straggling of energy loss by the same ions with the same energy in fully-depleted silicon-on-insulator （FDSOI） devices with ultra-thin sensitive silicon layers down to 2.5 rim. The absolute straggling of deposited energy decreases with decreasing thickness of the active silicon layer. While the relative straggling increases gradually with decreasing thickness of silicon films and exhibits a sharp rise as the thickness of the silicon film descends below a threshold value of 50 nm, with the dispersion of deposited energy ascending above ~10%. Ion species and energy dependence of the energy-loss straggling are also investigated. For a given beam, the dispersion of deposited energy results in large uncertainty on the actual linear energy transfer （LET） of incident ions, and thus single event effect （SEE） responses, which pose great challenges for traditional error rate prediction methods.
