Micro light sources are crucial tools for studying the interactions between light and matter at the micro/nanoscale,encompassing diverse applications across multiple disciplines.Despite numerous studies on reducing th...Micro light sources are crucial tools for studying the interactions between light and matter at the micro/nanoscale,encompassing diverse applications across multiple disciplines.Despite numerous studies on reducing the size of micro light sources and enhancing optical resolution,the efficient and simple fabrication of ultra-high-resolution micro light sources remains challenging due to its reliance on precise micro-nano processing technology and advanced processing equipment.In this study,a simple approach for the efficient fabrication of submicron light sources is proposed,namely shadow-assisted sidewall emission(SASE)technology.The SASE utilizes the widely adopted UV photolithography process,employing metal shadow modulation to precisely control the emission of light from polymer sidewalls,thereby obtaining photoluminescent light sources with submicron line widths.The SASE eliminates the need for complex and cumbersome manufacturing procedures.The effects of process parameters,including exposure dose,development time,and metal film thickness,on the linewidth of sources are investigated on detail.It is successfully demonstrated red,green,and blue submicron light sources.Finally,their potential application in the field of optical anti-counterfeiting is also demonstrated.We believe that the SASE proposed in this work provides a novel approach for the preparation and application of micro light sources.展开更多
Four types of submicron Ag-coated Cu particles with different Ag contents were prepared as sintering paste fillers,and the Ag contents of the particles were measured to be 10,20,30,and 40 wt.%.Four types of particles(...Four types of submicron Ag-coated Cu particles with different Ag contents were prepared as sintering paste fillers,and the Ag contents of the particles were measured to be 10,20,30,and 40 wt.%.Four types of particles(in order of increasing Ag content:A10,A20,A30,and A40)were surface-modified with stearic acid,to suppress the Ag shell dewetting and improve sinterability.The surface-modified particles were mixed with a polyol-based solvent to fabricate a resin-free paste.Subsequently,the pastes were screen-printed onto a slide glass and sintered at 250°C in a nitrogen atmosphere for 1-10 min to form an electrode.The electrical resistivity of the sintered film as a function of sintering time was measured using a four-point probe.All the four surface-modified Cu@Ag particles with different Ag contents exhibited decreased electrical resistivity.Particularly,the largest difference in values after and before the surface modification was observed for A40 with the highest Ag content;the electrical resistivities of the initial and surface-modified particles were 1.51×10^(-4) and 6.67×10^(-5)Ω·cm,respectively,after sintering for 10 min.The findings of this study confirmed that the surface modification using stearic acid effectively suppressed the dewetting of the Ag shell and improved the sinterability of the submicron Cu@Ag particles.展开更多
Although magnesium(Mg)alloys are the lightest among structural metals,their inadequate corrosion resistance makes them difficult to be used in energy-saving lightweight structures.Moreover,the improvement in corrosion...Although magnesium(Mg)alloys are the lightest among structural metals,their inadequate corrosion resistance makes them difficult to be used in energy-saving lightweight structures.Moreover,the improvement in corrosion resistance by the conventional surface treatments is always achieved at the expense of sacrificing the fatigue lifetime.In this study,high purity aluminum(Al)and AlMgSi alloy coatings were deposited on Mg alloys via an in-situ micro-forging(MF)assisted cold spray(MFCS)process for simultaneous higher corrosion resistance and longer fatigue lifetime.Besides contributing to a highly dense microstructure,the in-situ MF also greatly refines the grain of the deposited Al alloy coating to the sub-micrometer range due to the enhanced dynamic recrystallization and also generates notable compressive residual stress up to 210 MPa within the AlMgSi coating.The absence of secondary phases in the AlMgSi alloy coatings enable the coated Mg alloy with corrosion resistance,which is even better than its bulk AlMgSi counterparts.The unique combination of refined microstructure and the prominent compressive residual stress within the AlMgSi coatings,effectively delayed the crack initiation upon repeated dynamic loading,thereby leading to∼10 times increase in the fatigue lifetime of the Mg Alloy.However,although residual stress is also generated in the submmicro-sized grained pure Al coating,the low intrinsic strength of the coating layer leads to a lower fatigue lifetime than the uncoated Mg alloy substrate.The present work is aimed to provide a facile approach to break the trade-off between corrosion resistance improvement and fatigue lifetime of the coated Mg alloys.展开更多
This study delves into the intricate deposition dynamics of submicron particles within electric-flow coupled fields,underscoring the unique challenges posed by their minuscule size,aggregation tendencies,and biologica...This study delves into the intricate deposition dynamics of submicron particles within electric-flow coupled fields,underscoring the unique challenges posed by their minuscule size,aggregation tendencies,and biological reactivity.Employing an operando investigation system that synergizes microfluidic technology with advanced micro-visualization techniques within a lab-on-a-chip framework enables a meticulous examination of the dynamic deposition phenomena.The incorporation of object detection and deep learning methodologies in image processing streamlines the automatic identification and swift extraction of crucial data,effectively tackling the complexities associated with capturing and mitigating these hazardous particles.Combined with the analysis of the growth behavior of particle chain under different applied voltages,it established that a linear relationship exists between the applied voltage and θ.And there is a negative correlation between the average particle chain length and electric field strength at the collection electrode surface(4.2×10^(5)to 1.6×10^(6)V·m^(-1)).The morphology of the deposited particle agglomerate at different electric field strengths is proposed:dendritic agglomerate,long chain agglomerate,and short chain agglomerate.展开更多
Submicron scale temperature sensors are crucial for a range of applications,particularly in micro and na-noscale environments.One promising solution involves the use of active whispering gallery mode(WGM)microresonato...Submicron scale temperature sensors are crucial for a range of applications,particularly in micro and na-noscale environments.One promising solution involves the use of active whispering gallery mode(WGM)microresonators.These resonators can be remotely excited and read out using free-space structures,simplifying the process of sensing.In this study,we present a submicron-scale temperature sensor with a remarkable sensitivity up to 185 pm/℃based on a trian-gular MAPbI3 nanoplatelet(NPL)laser.Notably,as temperature changes,the peak wavelength of the laser line shifts lin-early.This unique characteristic allows for precise temperature sensing by tracking the peak wavelength of the NPL laser.The optical modes are confined within the perovskite NPL,which measures just 85 nm in height,due to total internal reflec-tion.Our NPL laser boasts several key features,including a high Q of~2610 and a low laser threshold of about 19.8μJ·cm^(−2).The combination of exceptional sensitivity and ultra-small size makes our WGM device an ideal candidate for integration into systems that demand compact temperature sensors.This advancement paves the way for significant prog-ress in the development of ultrasmall temperature sensors,opening new possibilities across various fields.展开更多
Cu 5%Cr alloy bulk material with submicron grains were fabricated by mechanical alloying and subsequent hot hydrostatic extrusion. The microstructure, mechanical properties and electrical conductivity of the alloy wer...Cu 5%Cr alloy bulk material with submicron grains were fabricated by mechanical alloying and subsequent hot hydrostatic extrusion. The microstructure, mechanical properties and electrical conductivity of the alloy were experimentally investigated, and the influence of the extrusion temperature on its microstructure and properties was made clear. Also, the strengthening mechanism of the alloy was discussed. It was revealed that the microstructure of the alloy is very fine, with an average grain size being about 100～120 nm, and thus possesses significant fine grain strengthening effect, leading to very high mechanical strength of 800～1 000 MPa. Meanwhile, the alloy also possesses quite good electrical conductivity and moderate tensile elongation, with the former in the range of 55%～70%(IACS) and the latter about 5% respectively.展开更多
The submicron powder mixtures of TiC-TiN-WC-Mo-C-Ni sintered at 1400degreesC or below in vacuum were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) an...The submicron powder mixtures of TiC-TiN-WC-Mo-C-Ni sintered at 1400degreesC or below in vacuum were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. The results showed that Mo2C formed at 800degreesC or below. Both WC and Mo2C disappeared at 1200degreesC, and TiN disappeared at 1250degreesC. In addition, the variations of lattice constants of the titanium carbonitride and nickel binder phase with sintering temperature were experimentally obtained, and the reason was analyzed.展开更多
In this study, WC-Co powder with WC submicron grain size of 0. 7 - 0. 9μm was used as feedstock powder to deposit wear resistant coating by home-made T J-9000 HVOF system. The deposition efficiency of the feedstock p...In this study, WC-Co powder with WC submicron grain size of 0. 7 - 0. 9μm was used as feedstock powder to deposit wear resistant coating by home-made T J-9000 HVOF system. The deposition efficiency of the feedstock powder was examined. Influences of the High Velocity Oxy-Fuel （HVOF） spraying parameters on the microstructures, phase compositions, microhardness, and wear resistance of sprayed coatings were investigated. The deposition efficiency of the feedstock powder was very high, and reached to 58%. The sprayed coatings were very dense, and their porosities were lower than 1% and could be lowered than 0. 42% with optimal spraying parameters. According to the X-ray Diffraction （ XRD ） analysis, the phase compositions of the sprayed coatings consisted of WC, Co, W2 C, and Co6 W6 C. W appeared at high flame power. The average microhardness of the coating was 1 100 HVo 1 and had reversely linear relationship with the porosity of coatings. The weight loss of the counter wear ring GCrl5 was 20 times than that of the sprayed WC-Co coating. At the load of 15 kg and rotational speed of 200 r/min of GCr15 counter wear ring, the friction coefficient was 0. 68 in the dry wear conditions. It was concluded that the sprayed submicron structural WC-12Co coating had good wear resistance.展开更多
Nickel-rich layered oxides have drawn sustainable attentions for lithium ion batteries owing to their higher theoretical capacities and lower cost.However,nickel-rich layered oxides also have exposed several defects f...Nickel-rich layered oxides have drawn sustainable attentions for lithium ion batteries owing to their higher theoretical capacities and lower cost.However,nickel-rich layered oxides also have exposed several defects for commercial application,such as uncontrollable ordered layered structure,which leads to higher energy barrier for Li+diffusion.In addition,suffering from structural mutability,the bulk nickelrich cathode materials likely trigger overall volumetric variation and intergranular cracks,thus obstructing the lithium ion diffusion path and shortening the service life of the whole device.Herein,we report wellordered layered Li Ni0.8Co0.1Mn0.1O2 submicron spheroidal particles via an optimized co-precipitation and investigated as LIBs cathodes for high-performance lithium storage.The as-fabricated Li Ni0.8Co0.1Mn0.1O2 delivers high initial capacity of 228 mAh g–1,remarkable energy density of 866 Wh kg–1,rapid Li ion diffusion coefficient(10–9cm2s–1)and low voltage decay.The remarkable electrochemical performance should be ascribed to the well-ordered layered structure and uniform submicron spheroidal particles,which enhance the structural stability and ameliorate strain relaxation via reducing the parcel size and shortening Li-ion diffusion distance.This work anticipatorily provides an inspiration to better design particle morphology for structural stability and rate capability in electrochemistry energy storage devices.展开更多
In this paper, we report a ferromagnetic resonance study on the permalloy film of submicron sized rectangular arrays prepared by electron beam lithography and the theoretical simulation to the non uniform demagnetiz...In this paper, we report a ferromagnetic resonance study on the permalloy film of submicron sized rectangular arrays prepared by electron beam lithography and the theoretical simulation to the non uniform demagnetizing effect and ferromagnetic resonance data. By theoretical simulation, the magnetization, gyromagnetic ratio and g value of the sample are determined. The theoretical curves of the dependence of the resonance field on the field orientation φ H fit well with the experimental data. When the steady magnetic field is applied near the film normal, a series of additional regular peaks (up to eight ) appeared in the FMR spectrum on the low field side of the main FMR peak. The resonance field of these side peaks decreases linearly with the peak number. The possible physical mechanism of these multiple peaks was discussed.展开更多
Base metal nickel is often used as the inner electrode in multilayer chip positive temperature coefficient resistance （PTCR）. The fine grain of ceramic powders and base metal nickel are necessary. This paper uses re...Base metal nickel is often used as the inner electrode in multilayer chip positive temperature coefficient resistance （PTCR）. The fine grain of ceramic powders and base metal nickel are necessary. This paper uses reducing hydrazine to gain submicron nickel powder whose diameter was 200-300 nm through adjusting the consumption of nucleating agent PVP properly. The submicron nickel powder could disperse well and was fit for co--fired of multilayer chip PTCR. It analyes the submicron nickel powder through x-ray Diffraction （XRD） and calculates the diameter of nickel by PDF cards. Using XRD analyses it obtains several conclusions： If the molar ratio of hydrazine hydrate and nickel sulfate is kept to be a constant, when enlarging the molar ratio of NaOH/Ni^2＋, the diameter of nickel powder would become smaller. When the temperature in the experiment raises to 70-80 ℃, nickel powder becomes smaller too. And if the molar ratio of NaOH/Ni2＋ is 4, when molar ratio of （C2H5O）2/Ni^2＋ increases, the diameter of nickel would reduce. Results from viewing the powders by optical microscope should be the fact that the electrode made by submicron nickel powder has a better formation and compactness. Furthermore, the sheet resistance testing shows that the electrode made by submicron nickel is smaller than that made by micron nickel.展开更多
The thin, long length and high smoothness silica photonic nanowires and taper optical fiber were fabricated using a simple and low cost chemical etching method. A two-steps wet etch process were used consisting of etc...The thin, long length and high smoothness silica photonic nanowires and taper optical fiber were fabricated using a simple and low cost chemical etching method. A two-steps wet etch process were used consisting of etching with 30% HF acid to remove cladding and 24% HF acid to decrease fiber core diameter. An approach for on-line monitoring of etching using 1300 nm light power transmitted in the optical fiber was used to determine the diameter of the remaining core and showed a transition between two different operation regimes of nanofiber from the embedded regime, where the mode was isolated from the environment, to the evanescent regime. The data indicated that the diameter of the silica fiber decreased linearly for both 30% and 24% HF acid with 1.2 and 0.1/zm/min grad diameter, respectively at room temperature, and more than 70% of the mode intensity could propagate outside fiber when the core diameter was less than 1μm. The results of fiber taper showed that the fiber was tapered by a factor of 20 while retaining a thin core structure and leaving about more than 85% of core structure.展开更多
In this study, we performed a highly time-resolved chemical characterization of nonrefractory submicron particles（NR-PM_1） in Beijing by using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer（HR...In this study, we performed a highly time-resolved chemical characterization of nonrefractory submicron particles（NR-PM_1） in Beijing by using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer（HR-ToF-AMS）. The results showed the average NR-PM_1 mass concentration to be 56.4 ± 58.0 μg/m^3, with a peak at 307.4 μg/m^3. Due to the high frequency of biomass burning in autumn, submicron particles significantly increased in organic content, which accounted for 51% of NR-PM_1 on average. Secondary inorganic aerosols（sulfate ＋ nitrate ＋ ammonium） accounted for 46% of NR-PM_1, of which sulfate,nitrate, and ammonium contributed 15%, 20%, and 11%, respectively. To determine the intrinsic relationships between the organic and inorganic species, we used the positive matrix factorization（PMF） model to merge the high-resolution mass spectra of the organic species and NO＋and NO_2~＋ions. The PMF analysis separated the mixed organic and nitrate（NO＋and NO_2~＋） spectra into four organic factors, including hydrocarbon-like organic aerosol（HOA）, oxygenated organic aerosol（OOA）, cooking organic aerosol（COA）, and biomass burning organic aerosol（BBOA）, as well as one nitrate inorganic aerosol（NIA） factor. COA（33%） and OOA（30%） contributed the most to the total organic aerosol（OA） mass, followed by BBOA（20%） and HOA（17%）. We successfully quantified the mass concentrations of the organic and inorganic nitrates by the NO＋and NO2＋ions signal in the organic and NIA factors. The organic nitrate mass varied from 0.01-6.8 μg/m^3, with an average of 1.0 ±1.1 μg/m^3, and organic nitrate components accounted for 10% of the total nitrate mass in this observation.展开更多
An 2024Al matrix composite reinforced with 36%(volume fraction)β-Si_(3)N_(4) particles was fabricated by pressure infiltration method,and its microstructure and the effect of annealing treatment on thermo-conductivit...An 2024Al matrix composite reinforced with 36%(volume fraction)β-Si_(3)N_(4) particles was fabricated by pressure infiltration method,and its microstructure and the effect of annealing treatment on thermo-conductivity were discussed.Si_(3)N_(4) particles distribute uniformly without any particle clustering and no apparent particle porosity or significant casting defects are observed in the composites.The combination of particles and matrix is well.The raw Si_(3)N_(4) particles are regular cylindrical polyhedron with flat surface and change to serrated surface in composite due to reactions during fabrication.Thermal conductivity of as-cast Si_(3)N_(4)p/2024 composite is 90.125 W/(m·K)at room temperature,and increases to 94.997 W/(m·K)after annealing treatment. The calculated results of thermal conductivity of the Si_(3)N_(4p)/Al composite by Maxwell model,H-S model and PG model are lower than experimental results while that by ROM model is higher.展开更多
To improve the removal efficiency of such submicron inclusions,we designed an argon blowing method for an RH facility based on mathematical simulations.The effect of the argon blowing on the liquid steel flow and the ...To improve the removal efficiency of such submicron inclusions,we designed an argon blowing method for an RH facility based on mathematical simulations.The effect of the argon blowing on the liquid steel flow and the movement of submicron inclusions was studied using the k-ε flow model coupled with the DPM model for inclusion movement based on fluid computational dynamics in FLUENT.It was found that a more uniform argon flow can be achieved in the up-leg snorkel with a new nozzle position and inner diameter,which resulted in a favorable up-lifting and mixing movement.The new design also increased the circulation rate of molten steel in the RH chamber.The increased turbulent kinetic energy and turbulent dispersing rate enhanced the collision probability of submicron inclusions,which results in an improved removal for 0.5-1 μm inclusions.The proposed RH facility could increase the removal rate of submicron inclusions from the original 57.1% to 66.4%,which improves the magnetic properties of non-oriented silicon steel.展开更多
Taiwan Strait is a special channel for subtropical East Asian Monsoon and its western coast is an important economic zone in China. In this study, a suburban site in the city of Xiamen on the western coast of Taiwan S...Taiwan Strait is a special channel for subtropical East Asian Monsoon and its western coast is an important economic zone in China. In this study, a suburban site in the city of Xiamen on the western coast of Taiwan Strait was selected for fine aerosol study to improve the understanding of air pollution sources in this region. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer（HR-To F-AMS） and an Aethalometer were deployed to measure fine aerosol composition with a time resolution of 5 min from May 1to 18, 2015. The average mass concentration of PM1 was 46.2 ± 26.3 μg/m^3 for the entire campaign. Organics（28.3%）, sulfate（24.9%）, and nitrate（20.6%） were the major components in the fine particles, followed by ammonium, black carbon（BC）, and chloride. Evolution of nitrate concentration and size distribution indicated that local NOx emissions played a key role in high fine particle pollution in Xiamen. In addition, organic nitrate was found to account for 9.0%–13.8% of the total measured nitrate. Positive Matrix Factorization（PMF）conducted with high-resolution organic mass spectra dataset differentiated the organic aerosol into three components, including a hydrocarbon-like organic aerosol（HOA） and two oxygenated organic aerosols（SV-OOA and LV-OOA）, which on average accounted for 27.6%,28.8%, and 43.6% of the total organic mass, respectively. The relationship between the mass concentration of submicron particle species and wind further confirmed that all major fine particle species were influenced by both strong local emissions in the southeastern area of Xiamen and regional transport through the Taiwan Strait.展开更多
Submicron aerosol is of extensive concern not only due to its significant impact on air quality but also because it is detrimental to human health.In this study,we investigated the characteristics,sources and chemical...Submicron aerosol is of extensive concern not only due to its significant impact on air quality but also because it is detrimental to human health.In this study,we investigated the characteristics,sources and chemical processes of submicron aerosol based on realtime online measurements of submicron aerosols(NR-PM 1)during December 2015 at an urban site in Beijing.The average mass concentration of NR-PM 1 was 92.5±84.9μg/m^(3),the hourly maximum was 459.1μg/m^(3) during the entire observation.The organic aerosol(OA)(55%)was the largest contributor to NR-PM 1.The average mass concentration of PAHs was 0.217±0.247μg/m^(3),exhibiting the highest concentration at night and the lowest levels in the daytime.The average mass concentration of organic nitrate was 2.52±2.36μg/m^(3) and that of inorganic nitrate was 7.62±8.22μg/m^(3),accounting for 36%and 64%,respectively,of the total nitrate mass.Positive matrix factorization(PMF)differentiated the OA into five chemical components including LV-OOA,SV-OOA,COA,HOA and CCOA,accounting for 22%,16%,13%,25%and 24%respectively,of the total OA.The average NR-PM 1 mass concentration on the heavy polluted days(HPD)was 182.8±70.2μg/m^(3),which was approximately 9 times that on clean days(CD).The enhanced secondary formation of SNA was evident on HPD,especially the rapid increase of sulfate(23%)and nitrate(19%).展开更多
Submicron-sized peanut-shaped poly（methyl methacrylate）/polystyrene （PMMA/PS） particles were successfully synthesized by seeded soap-free emulsion polymerization of styrene on the spherical crosslinked PMMA seed p...Submicron-sized peanut-shaped poly（methyl methacrylate）/polystyrene （PMMA/PS） particles were successfully synthesized by seeded soap-free emulsion polymerization of styrene on the spherical crosslinked PMMA seed particles. The obtained peanut- shaped particles showed a novel internal morphology： PS phase formed one domain which linked to the other domain having PMMA core encased by PS shell.展开更多
A new cement free iron trough castable was prepared with dense corundum and silicon carbide as the main raw materials and submicron SiO_(2) powder(d_(50)=0.242μm,SiO_(2)=99.9 mass%)as the binder.The effect of the sub...A new cement free iron trough castable was prepared with dense corundum and silicon carbide as the main raw materials and submicron SiO_(2) powder(d_(50)=0.242μm,SiO_(2)=99.9 mass%)as the binder.The effect of the submicron SiO_(2) powder addition(3%,4%,5%,6%,7%,8%,and 9%,by mass,respectively)on the properties of the prepared castables was studied.The working mechanism of submicron SiO_(2) powder was analyzed from the perspective of the particle size distribution and infrared absorption spectrum.The results show that:(1)cement free iron trough castables can be prepared using submicron SiO_(2) powder alone as the binder;(2)compared with traditional castables,the cement free castables have made a breakthrough in the water addition and hot modulus of rupture.The optimal submicron SiO_(2) powder addition is 4%-6%.展开更多
Based on focused ion beam and shear friction apparatus data, the multi-resolutions （0.2 nm-5μm） volume roughness ＆ asperity contact （VR ＆ AC） three-dimensional structure on principle slip surface interface-surf...Based on focused ion beam and shear friction apparatus data, the multi-resolutions （0.2 nm-5μm） volume roughness ＆ asperity contact （VR ＆ AC） three-dimensional structure on principle slip surface interface-surface （PSS-IS） is measured on high performance computational platform; and physical plastic-creep friction model is established by using hybrid hyper-singular integral equation ＆ lattice Boltzmann ＆ lattice Green function （BE-LB-LG）. The correlation of rheological property and VR ＆ AC evolution under transient （10 μs） macro-normal stress （18-300 MPa） and slip rate （0.25-7.5 m/s） are obtained; and the PSS-IS friction in co-seismic flash heating is quantitative analyzed for the first time.展开更多
基金supported by Natural Science Foundation of the Fujian Province,China(2024J010016)the National Key R&D Program of China(2021YFB3600400)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Project(2020ZZ113,2021ZZ130)。
文摘Micro light sources are crucial tools for studying the interactions between light and matter at the micro/nanoscale,encompassing diverse applications across multiple disciplines.Despite numerous studies on reducing the size of micro light sources and enhancing optical resolution,the efficient and simple fabrication of ultra-high-resolution micro light sources remains challenging due to its reliance on precise micro-nano processing technology and advanced processing equipment.In this study,a simple approach for the efficient fabrication of submicron light sources is proposed,namely shadow-assisted sidewall emission(SASE)technology.The SASE utilizes the widely adopted UV photolithography process,employing metal shadow modulation to precisely control the emission of light from polymer sidewalls,thereby obtaining photoluminescent light sources with submicron line widths.The SASE eliminates the need for complex and cumbersome manufacturing procedures.The effects of process parameters,including exposure dose,development time,and metal film thickness,on the linewidth of sources are investigated on detail.It is successfully demonstrated red,green,and blue submicron light sources.Finally,their potential application in the field of optical anti-counterfeiting is also demonstrated.We believe that the SASE proposed in this work provides a novel approach for the preparation and application of micro light sources.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.2021R1A2C1007400)supported,partly,by the National R&D Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(Nos.NRF-2020M3H4A3106383,NRF2020M3H4A3081764)+1 种基金supported,partly,by ETRI(No.21YB1610)supported by a Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(MOTIE)(No.P0008458,HRD Program for Industrial Innovation)。
文摘Four types of submicron Ag-coated Cu particles with different Ag contents were prepared as sintering paste fillers,and the Ag contents of the particles were measured to be 10,20,30,and 40 wt.%.Four types of particles(in order of increasing Ag content:A10,A20,A30,and A40)were surface-modified with stearic acid,to suppress the Ag shell dewetting and improve sinterability.The surface-modified particles were mixed with a polyol-based solvent to fabricate a resin-free paste.Subsequently,the pastes were screen-printed onto a slide glass and sintered at 250°C in a nitrogen atmosphere for 1-10 min to form an electrode.The electrical resistivity of the sintered film as a function of sintering time was measured using a four-point probe.All the four surface-modified Cu@Ag particles with different Ag contents exhibited decreased electrical resistivity.Particularly,the largest difference in values after and before the surface modification was observed for A40 with the highest Ag content;the electrical resistivities of the initial and surface-modified particles were 1.51×10^(-4) and 6.67×10^(-5)Ω·cm,respectively,after sintering for 10 min.The findings of this study confirmed that the surface modification using stearic acid effectively suppressed the dewetting of the Ag shell and improved the sinterability of the submicron Cu@Ag particles.
基金supported by the National Natural Science Foundation of China(51875443)Guangdong Basic and Applied Basic Research Foundation(2019B1515120016,202002030290).
文摘Although magnesium(Mg)alloys are the lightest among structural metals,their inadequate corrosion resistance makes them difficult to be used in energy-saving lightweight structures.Moreover,the improvement in corrosion resistance by the conventional surface treatments is always achieved at the expense of sacrificing the fatigue lifetime.In this study,high purity aluminum(Al)and AlMgSi alloy coatings were deposited on Mg alloys via an in-situ micro-forging(MF)assisted cold spray(MFCS)process for simultaneous higher corrosion resistance and longer fatigue lifetime.Besides contributing to a highly dense microstructure,the in-situ MF also greatly refines the grain of the deposited Al alloy coating to the sub-micrometer range due to the enhanced dynamic recrystallization and also generates notable compressive residual stress up to 210 MPa within the AlMgSi coating.The absence of secondary phases in the AlMgSi alloy coatings enable the coated Mg alloy with corrosion resistance,which is even better than its bulk AlMgSi counterparts.The unique combination of refined microstructure and the prominent compressive residual stress within the AlMgSi coatings,effectively delayed the crack initiation upon repeated dynamic loading,thereby leading to∼10 times increase in the fatigue lifetime of the Mg Alloy.However,although residual stress is also generated in the submmicro-sized grained pure Al coating,the low intrinsic strength of the coating layer leads to a lower fatigue lifetime than the uncoated Mg alloy substrate.The present work is aimed to provide a facile approach to break the trade-off between corrosion resistance improvement and fatigue lifetime of the coated Mg alloys.
基金supported by the National Natural Science Foundation of China(52200130,22308100).
文摘This study delves into the intricate deposition dynamics of submicron particles within electric-flow coupled fields,underscoring the unique challenges posed by their minuscule size,aggregation tendencies,and biological reactivity.Employing an operando investigation system that synergizes microfluidic technology with advanced micro-visualization techniques within a lab-on-a-chip framework enables a meticulous examination of the dynamic deposition phenomena.The incorporation of object detection and deep learning methodologies in image processing streamlines the automatic identification and swift extraction of crucial data,effectively tackling the complexities associated with capturing and mitigating these hazardous particles.Combined with the analysis of the growth behavior of particle chain under different applied voltages,it established that a linear relationship exists between the applied voltage and θ.And there is a negative correlation between the average particle chain length and electric field strength at the collection electrode surface(4.2×10^(5)to 1.6×10^(6)V·m^(-1)).The morphology of the deposited particle agglomerate at different electric field strengths is proposed:dendritic agglomerate,long chain agglomerate,and short chain agglomerate.
文摘Submicron scale temperature sensors are crucial for a range of applications,particularly in micro and na-noscale environments.One promising solution involves the use of active whispering gallery mode(WGM)microresonators.These resonators can be remotely excited and read out using free-space structures,simplifying the process of sensing.In this study,we present a submicron-scale temperature sensor with a remarkable sensitivity up to 185 pm/℃based on a trian-gular MAPbI3 nanoplatelet(NPL)laser.Notably,as temperature changes,the peak wavelength of the laser line shifts lin-early.This unique characteristic allows for precise temperature sensing by tracking the peak wavelength of the NPL laser.The optical modes are confined within the perovskite NPL,which measures just 85 nm in height,due to total internal reflec-tion.Our NPL laser boasts several key features,including a high Q of~2610 and a low laser threshold of about 19.8μJ·cm^(−2).The combination of exceptional sensitivity and ultra-small size makes our WGM device an ideal candidate for integration into systems that demand compact temperature sensors.This advancement paves the way for significant prog-ress in the development of ultrasmall temperature sensors,opening new possibilities across various fields.
文摘Cu 5%Cr alloy bulk material with submicron grains were fabricated by mechanical alloying and subsequent hot hydrostatic extrusion. The microstructure, mechanical properties and electrical conductivity of the alloy were experimentally investigated, and the influence of the extrusion temperature on its microstructure and properties was made clear. Also, the strengthening mechanism of the alloy was discussed. It was revealed that the microstructure of the alloy is very fine, with an average grain size being about 100～120 nm, and thus possesses significant fine grain strengthening effect, leading to very high mechanical strength of 800～1 000 MPa. Meanwhile, the alloy also possesses quite good electrical conductivity and moderate tensile elongation, with the former in the range of 55%～70%(IACS) and the latter about 5% respectively.
基金This work wasfinancially supported by the National Natural Science Foundation Of China (50074017), the NationalDoctorate Progr
文摘The submicron powder mixtures of TiC-TiN-WC-Mo-C-Ni sintered at 1400degreesC or below in vacuum were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. The results showed that Mo2C formed at 800degreesC or below. Both WC and Mo2C disappeared at 1200degreesC, and TiN disappeared at 1250degreesC. In addition, the variations of lattice constants of the titanium carbonitride and nickel binder phase with sintering temperature were experimentally obtained, and the reason was analyzed.
文摘In this study, WC-Co powder with WC submicron grain size of 0. 7 - 0. 9μm was used as feedstock powder to deposit wear resistant coating by home-made T J-9000 HVOF system. The deposition efficiency of the feedstock powder was examined. Influences of the High Velocity Oxy-Fuel （HVOF） spraying parameters on the microstructures, phase compositions, microhardness, and wear resistance of sprayed coatings were investigated. The deposition efficiency of the feedstock powder was very high, and reached to 58%. The sprayed coatings were very dense, and their porosities were lower than 1% and could be lowered than 0. 42% with optimal spraying parameters. According to the X-ray Diffraction （ XRD ） analysis, the phase compositions of the sprayed coatings consisted of WC, Co, W2 C, and Co6 W6 C. W appeared at high flame power. The average microhardness of the coating was 1 100 HVo 1 and had reversely linear relationship with the porosity of coatings. The weight loss of the counter wear ring GCrl5 was 20 times than that of the sprayed WC-Co coating. At the load of 15 kg and rotational speed of 200 r/min of GCr15 counter wear ring, the friction coefficient was 0. 68 in the dry wear conditions. It was concluded that the sprayed submicron structural WC-12Co coating had good wear resistance.
基金supported by the National Natural Science Foundation of China (21573083)1000 Young Talent (to Deli Wang)the Innovation Research Funds of HuaZhong University of Science and Technology (2017KFYXJJ164)。
文摘Nickel-rich layered oxides have drawn sustainable attentions for lithium ion batteries owing to their higher theoretical capacities and lower cost.However,nickel-rich layered oxides also have exposed several defects for commercial application,such as uncontrollable ordered layered structure,which leads to higher energy barrier for Li+diffusion.In addition,suffering from structural mutability,the bulk nickelrich cathode materials likely trigger overall volumetric variation and intergranular cracks,thus obstructing the lithium ion diffusion path and shortening the service life of the whole device.Herein,we report wellordered layered Li Ni0.8Co0.1Mn0.1O2 submicron spheroidal particles via an optimized co-precipitation and investigated as LIBs cathodes for high-performance lithium storage.The as-fabricated Li Ni0.8Co0.1Mn0.1O2 delivers high initial capacity of 228 mAh g–1,remarkable energy density of 866 Wh kg–1,rapid Li ion diffusion coefficient(10–9cm2s–1)and low voltage decay.The remarkable electrochemical performance should be ascribed to the well-ordered layered structure and uniform submicron spheroidal particles,which enhance the structural stability and ameliorate strain relaxation via reducing the parcel size and shortening Li-ion diffusion distance.This work anticipatorily provides an inspiration to better design particle morphology for structural stability and rate capability in electrochemistry energy storage devices.
文摘In this paper, we report a ferromagnetic resonance study on the permalloy film of submicron sized rectangular arrays prepared by electron beam lithography and the theoretical simulation to the non uniform demagnetizing effect and ferromagnetic resonance data. By theoretical simulation, the magnetization, gyromagnetic ratio and g value of the sample are determined. The theoretical curves of the dependence of the resonance field on the field orientation φ H fit well with the experimental data. When the steady magnetic field is applied near the film normal, a series of additional regular peaks (up to eight ) appeared in the FMR spectrum on the low field side of the main FMR peak. The resonance field of these side peaks decreases linearly with the peak number. The possible physical mechanism of these multiple peaks was discussed.
基金Project supported by the "863" (Grant No. SQ2008AA03Z4471960)the National Natural Science Foundation of China(Grant No. 60676050)
文摘Base metal nickel is often used as the inner electrode in multilayer chip positive temperature coefficient resistance （PTCR）. The fine grain of ceramic powders and base metal nickel are necessary. This paper uses reducing hydrazine to gain submicron nickel powder whose diameter was 200-300 nm through adjusting the consumption of nucleating agent PVP properly. The submicron nickel powder could disperse well and was fit for co--fired of multilayer chip PTCR. It analyes the submicron nickel powder through x-ray Diffraction （XRD） and calculates the diameter of nickel by PDF cards. Using XRD analyses it obtains several conclusions： If the molar ratio of hydrazine hydrate and nickel sulfate is kept to be a constant, when enlarging the molar ratio of NaOH/Ni^2＋, the diameter of nickel powder would become smaller. When the temperature in the experiment raises to 70-80 ℃, nickel powder becomes smaller too. And if the molar ratio of NaOH/Ni2＋ is 4, when molar ratio of （C2H5O）2/Ni^2＋ increases, the diameter of nickel would reduce. Results from viewing the powders by optical microscope should be the fact that the electrode made by submicron nickel powder has a better formation and compactness. Furthermore, the sheet resistance testing shows that the electrode made by submicron nickel is smaller than that made by micron nickel.
基金carried out in School of Physics and Astronomy in University of Southampton, UK and founded by both of IIE/SRF and CARA
文摘The thin, long length and high smoothness silica photonic nanowires and taper optical fiber were fabricated using a simple and low cost chemical etching method. A two-steps wet etch process were used consisting of etching with 30% HF acid to remove cladding and 24% HF acid to decrease fiber core diameter. An approach for on-line monitoring of etching using 1300 nm light power transmitted in the optical fiber was used to determine the diameter of the remaining core and showed a transition between two different operation regimes of nanofiber from the embedded regime, where the mode was isolated from the environment, to the evanescent regime. The data indicated that the diameter of the silica fiber decreased linearly for both 30% and 24% HF acid with 1.2 and 0.1/zm/min grad diameter, respectively at room temperature, and more than 70% of the mode intensity could propagate outside fiber when the core diameter was less than 1μm. The results of fiber taper showed that the fiber was tapered by a factor of 20 while retaining a thin core structure and leaving about more than 85% of core structure.
基金supported by“Strategic Priority Research Program”of the Chinese Academy of Sciences(No.XDB05020201)the Beijing Natural Science Foundation(No.8142034)
文摘In this study, we performed a highly time-resolved chemical characterization of nonrefractory submicron particles（NR-PM_1） in Beijing by using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer（HR-ToF-AMS）. The results showed the average NR-PM_1 mass concentration to be 56.4 ± 58.0 μg/m^3, with a peak at 307.4 μg/m^3. Due to the high frequency of biomass burning in autumn, submicron particles significantly increased in organic content, which accounted for 51% of NR-PM_1 on average. Secondary inorganic aerosols（sulfate ＋ nitrate ＋ ammonium） accounted for 46% of NR-PM_1, of which sulfate,nitrate, and ammonium contributed 15%, 20%, and 11%, respectively. To determine the intrinsic relationships between the organic and inorganic species, we used the positive matrix factorization（PMF） model to merge the high-resolution mass spectra of the organic species and NO＋and NO_2~＋ions. The PMF analysis separated the mixed organic and nitrate（NO＋and NO_2~＋） spectra into four organic factors, including hydrocarbon-like organic aerosol（HOA）, oxygenated organic aerosol（OOA）, cooking organic aerosol（COA）, and biomass burning organic aerosol（BBOA）, as well as one nitrate inorganic aerosol（NIA） factor. COA（33%） and OOA（30%） contributed the most to the total organic aerosol（OA） mass, followed by BBOA（20%） and HOA（17%）. We successfully quantified the mass concentrations of the organic and inorganic nitrates by the NO＋and NO2＋ions signal in the organic and NIA factors. The organic nitrate mass varied from 0.01-6.8 μg/m^3, with an average of 1.0 ±1.1 μg/m^3, and organic nitrate components accounted for 10% of the total nitrate mass in this observation.
基金Project(2003AA305110)supported by the Hi-tech Research and Development Program of China。
文摘An 2024Al matrix composite reinforced with 36%(volume fraction)β-Si_(3)N_(4) particles was fabricated by pressure infiltration method,and its microstructure and the effect of annealing treatment on thermo-conductivity were discussed.Si_(3)N_(4) particles distribute uniformly without any particle clustering and no apparent particle porosity or significant casting defects are observed in the composites.The combination of particles and matrix is well.The raw Si_(3)N_(4) particles are regular cylindrical polyhedron with flat surface and change to serrated surface in composite due to reactions during fabrication.Thermal conductivity of as-cast Si_(3)N_(4)p/2024 composite is 90.125 W/(m·K)at room temperature,and increases to 94.997 W/(m·K)after annealing treatment. The calculated results of thermal conductivity of the Si_(3)N_(4p)/Al composite by Maxwell model,H-S model and PG model are lower than experimental results while that by ROM model is higher.
基金Funded by the National Natural Science Foundation of China(No.51804231)the Key R&D Program of Hubei Province(No.2020BAA027)。
文摘To improve the removal efficiency of such submicron inclusions,we designed an argon blowing method for an RH facility based on mathematical simulations.The effect of the argon blowing on the liquid steel flow and the movement of submicron inclusions was studied using the k-ε flow model coupled with the DPM model for inclusion movement based on fluid computational dynamics in FLUENT.It was found that a more uniform argon flow can be achieved in the up-leg snorkel with a new nozzle position and inner diameter,which resulted in a favorable up-lifting and mixing movement.The new design also increased the circulation rate of molten steel in the RH chamber.The increased turbulent kinetic energy and turbulent dispersing rate enhanced the collision probability of submicron inclusions,which results in an improved removal for 0.5-1 μm inclusions.The proposed RH facility could increase the removal rate of submicron inclusions from the original 57.1% to 66.4%,which improves the magnetic properties of non-oriented silicon steel.
基金supported by the National Natural Science Foundation of China(21277003)the Ministry of Science and Technology of China(2013CB228503)the Shenzhen Science&Technology Plan
文摘Taiwan Strait is a special channel for subtropical East Asian Monsoon and its western coast is an important economic zone in China. In this study, a suburban site in the city of Xiamen on the western coast of Taiwan Strait was selected for fine aerosol study to improve the understanding of air pollution sources in this region. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer（HR-To F-AMS） and an Aethalometer were deployed to measure fine aerosol composition with a time resolution of 5 min from May 1to 18, 2015. The average mass concentration of PM1 was 46.2 ± 26.3 μg/m^3 for the entire campaign. Organics（28.3%）, sulfate（24.9%）, and nitrate（20.6%） were the major components in the fine particles, followed by ammonium, black carbon（BC）, and chloride. Evolution of nitrate concentration and size distribution indicated that local NOx emissions played a key role in high fine particle pollution in Xiamen. In addition, organic nitrate was found to account for 9.0%–13.8% of the total measured nitrate. Positive Matrix Factorization（PMF）conducted with high-resolution organic mass spectra dataset differentiated the organic aerosol into three components, including a hydrocarbon-like organic aerosol（HOA） and two oxygenated organic aerosols（SV-OOA and LV-OOA）, which on average accounted for 27.6%,28.8%, and 43.6% of the total organic mass, respectively. The relationship between the mass concentration of submicron particle species and wind further confirmed that all major fine particle species were influenced by both strong local emissions in the southeastern area of Xiamen and regional transport through the Taiwan Strait.
基金supported by the Ministry of Science and Technology of China(No.2017YFC0210000)the Science and Technology Planned Project in Guizhou Province(Qian Kehe Foundation[2019]1Y175)the Introducing Talent in Guizhou University(2018)。
文摘Submicron aerosol is of extensive concern not only due to its significant impact on air quality but also because it is detrimental to human health.In this study,we investigated the characteristics,sources and chemical processes of submicron aerosol based on realtime online measurements of submicron aerosols(NR-PM 1)during December 2015 at an urban site in Beijing.The average mass concentration of NR-PM 1 was 92.5±84.9μg/m^(3),the hourly maximum was 459.1μg/m^(3) during the entire observation.The organic aerosol(OA)(55%)was the largest contributor to NR-PM 1.The average mass concentration of PAHs was 0.217±0.247μg/m^(3),exhibiting the highest concentration at night and the lowest levels in the daytime.The average mass concentration of organic nitrate was 2.52±2.36μg/m^(3) and that of inorganic nitrate was 7.62±8.22μg/m^(3),accounting for 36%and 64%,respectively,of the total nitrate mass.Positive matrix factorization(PMF)differentiated the OA into five chemical components including LV-OOA,SV-OOA,COA,HOA and CCOA,accounting for 22%,16%,13%,25%and 24%respectively,of the total OA.The average NR-PM 1 mass concentration on the heavy polluted days(HPD)was 182.8±70.2μg/m^(3),which was approximately 9 times that on clean days(CD).The enhanced secondary formation of SNA was evident on HPD,especially the rapid increase of sulfate(23%)and nitrate(19%).
基金supported by National Natural Science Foundation of China(No.50943028)Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘Submicron-sized peanut-shaped poly（methyl methacrylate）/polystyrene （PMMA/PS） particles were successfully synthesized by seeded soap-free emulsion polymerization of styrene on the spherical crosslinked PMMA seed particles. The obtained peanut- shaped particles showed a novel internal morphology： PS phase formed one domain which linked to the other domain having PMMA core encased by PS shell.
基金support from the National Natural Science Foundation of China(NSFC,No.51804233)。
文摘A new cement free iron trough castable was prepared with dense corundum and silicon carbide as the main raw materials and submicron SiO_(2) powder(d_(50)=0.242μm,SiO_(2)=99.9 mass%)as the binder.The effect of the submicron SiO_(2) powder addition(3%,4%,5%,6%,7%,8%,and 9%,by mass,respectively)on the properties of the prepared castables was studied.The working mechanism of submicron SiO_(2) powder was analyzed from the perspective of the particle size distribution and infrared absorption spectrum.The results show that:(1)cement free iron trough castables can be prepared using submicron SiO_(2) powder alone as the binder;(2)compared with traditional castables,the cement free castables have made a breakthrough in the water addition and hot modulus of rupture.The optimal submicron SiO_(2) powder addition is 4%-6%.
文摘Based on focused ion beam and shear friction apparatus data, the multi-resolutions （0.2 nm-5μm） volume roughness ＆ asperity contact （VR ＆ AC） three-dimensional structure on principle slip surface interface-surface （PSS-IS） is measured on high performance computational platform; and physical plastic-creep friction model is established by using hybrid hyper-singular integral equation ＆ lattice Boltzmann ＆ lattice Green function （BE-LB-LG）. The correlation of rheological property and VR ＆ AC evolution under transient （10 μs） macro-normal stress （18-300 MPa） and slip rate （0.25-7.5 m/s） are obtained; and the PSS-IS friction in co-seismic flash heating is quantitative analyzed for the first time.
