Double glow plasma surface metallurgy technique was used to fabricate a Fe?Al?Cr?Nb alloyed layer onto the surface of the 45 steel. The microstructures and composition of th?eA Fl?eCr?Nb alloyed layer were analyzed by...Double glow plasma surface metallurgy technique was used to fabricate a Fe?Al?Cr?Nb alloyed layer onto the surface of the 45 steel. The microstructures and composition of th?eA Fl?eCr?Nb alloyed layer were analyzed by scanning electronic microscopy, X-ray diffraction and energy dispersive spectroscopy. The results indicate thatthe 20 μm alloyed layer is homogeneous and compact. The alloyed elements exhibit a gradient distribution along the cross section. Microhardness and nanoindentation tests imply that the surface hardness of the alloyed layer reaches HV 580, which is almost 2.8 times that of the substrate. Compared with the substrate, the alloyed layer has a much smaller displacement and a larger elastic modulus. According to the friction and wear tests at room temperature, the? FeAl?Cr?Nb alloyed layer has lower friction coefficient and less wear mass, implying that the Fe?Al?Cr?Nb alloyed layer can effectively improve the surface hardness and wear resistance of the substrate.展开更多
AIM: To prepare a new-type soft intraocular lens (IOL) that silicone intraocular lenses (IOLs) were modified by surface modification technique to assess IOLs biocompatibility. METHODS: With the technique of ion beam c...AIM: To prepare a new-type soft intraocular lens (IOL) that silicone intraocular lenses (IOLs) were modified by surface modification technique to assess IOLs biocompatibility. METHODS: With the technique of ion beam combined with low temperature and low pressure plasma, the surface characteristics of the IOLs including physical and optical properties were determined by the instruments of IOLs resolution, UV/VIS scanning spectrophotometer, contact angle measurement system, electron spectroscopy for chemical analysis (ESCA) and scanning electron microscope (SEM). RESULTS: The color of titanium (Ti) modified IOLs was light yellow and that of titanium nitride (TiN) modified IOLs was light brown. The absorptive degree of ultraviolet rays and the hydrophilicity of the surfaces of modified IOLs were increased, and appeared suitable chemical compositions. The resolution of unmodified and modified IOLs reached normal standard. The surfaces of unmodified and Ti-modified IOLs appeared uniform. The surfaces of TIN-modified IOLs presented fine porcelain structure. CONCLUSION: The optical properties of all IOLs and the surface morphology of the modified IOLs were not affected by modification processes. The surface properties of the modified IOLs were improved.展开更多
TiAl-based alloys have received extensive attention recently due to their excellent properties. However, the weak oxidation resistance at temperatures higher than 800℃ can limit their further high-temperature structu...TiAl-based alloys have received extensive attention recently due to their excellent properties. However, the weak oxidation resistance at temperatures higher than 800℃ can limit their further high-temperature structural applications.To improve the oxidation resistance of a high-Nb-content γ-TiAl alloy(Ti-45 Al-8.5 Nb, in units of at.%), a chromium(Cr)coating is prepared by using the plasma surface alloying technique, separately, at 800℃ and 1000℃. The x-ray diffraction(XRD) patterns reveal that an oxide surface layer consisting of Cr2O3, Al2O3, and TiO2 is produced on the Cr-coated Nb containing γ-TiAl substrates during the initial oxidation. However, the Cr2O3 is dominated in the oxide surface layer after being isothermally oxidized for 300 h. The oxidation kinetic curves are composed of a parabolic law stage(≤ 90 h) and a biquadratic law stage(≥ 90 h), fit by weight–gain curves. Due to diffusion in the fabrication process and oxidation process,the Cr-coated specimens have an adhesion force after being isothermally oxidized, specifically 69 N for a specimen after oxidation for 300 h. These results demonstrate that the Cr coating enhances the oxidation resistance and adhesion of a Ti-45 Al-8.5 Nb alloy, which may provide a new feasible scheme for designing oxidation protection layers.展开更多
We present a 3D approach to numerical modeling of the borehole-surface electromagnetic (BSEM) method. The 3D electromagnetic response created by a vertical line current source in a layered medium is modeled using th...We present a 3D approach to numerical modeling of the borehole-surface electromagnetic (BSEM) method. The 3D electromagnetic response created by a vertical line current source in a layered medium is modeled using the 3D integral equation method. The modeling results are consistent with analytical solutions. 3D Born approximation inversion of BSEM data is also conducted for reservoir delineation. The inversion method is verified by a synthetic reservoir model.展开更多
RE(NO_3)_3-HNO_3-P507-kerosene extraction system(RE=La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er, Tm,Yb,Lu,Y)was studied by the response surface technique.14 models for extracting single rare earth ele- ment in a broad range of a...RE(NO_3)_3-HNO_3-P507-kerosene extraction system(RE=La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er, Tm,Yb,Lu,Y)was studied by the response surface technique.14 models for extracting single rare earth ele- ment in a broad range of acidity and initial rare earth concentration were obtained by using the stepwise regression method.Three-dimensional display of the response surface of the model of extracting Er^(3+)was showed as an example,which reveals clearly the dependence of distribution ratio upon both initial acidity and ini- tial rare earth concentration.展开更多
We make use of the images from the Sloan Digital Sky Survey Stripe 82(Stripe 82) to present an analysis of r band surface brightness profiles and radial color gradients(g-r,u-r) in our sample of 111 nearby early-t...We make use of the images from the Sloan Digital Sky Survey Stripe 82(Stripe 82) to present an analysis of r band surface brightness profiles and radial color gradients(g-r,u-r) in our sample of 111 nearby early-type galaxies(ETGs) .Thanks to the Stripe 82 images,each of which is co-added from about 50 single frames,we are able to pay special attention to the low-surface-brightness areas(LSB areas) of the galaxies.The LSB areas affect the Sérsic fittings and concentration indices by making both of the indices less than the typical values for ETGs.In the Sérsic fits to all the surface brightness profiles,we found some Sérsic indices that range from 1.5 to 2.5,much smaller than those of typical de Vaucouleur profiles and relatively close to those of exponential disks,and some others much larger than four but still with accurate fitting.Two galaxies cannot be fitted with a single Sérsic profile,but once we try double Sérsic profiles,the fittings are improved:one with a profile relatively close to the de Vaucouleur law in the inner area and a profile relatively close to an exponential law in the LSB area,the other with a nice fitting in the inner area but still having a failed fitting in the outer area.About 60%of the sample has negative color gradients(red-core) within 1.5Re,much more than the approximately 10%positive ones(blue-core) within the same radius.However,taking into account the LSB areas,we find that the color gradients are not necessarily monotonic:about one third of the red-core(or blue-core) galaxies have positive(or negative) color gradients in the outer areas. So LSB areas not only make ETGs’Sérsic profiles deviate from de Vaucouleur ones and shift to the disk end,but also reveal that quite a number of ETGs have opposite color gradients in inner and outer areas.These outcomes remind us of the necessity of double-Sérsic fitting.These LSB phenomena may be interpreted by mergers and thus have different metallicity in the outer areas.Isophotal parameters are also discussed briefly in this paper with the following conclusion:there are more disky nearby ETGs that are identified than boxy ones.展开更多
Electron density (Ne) in a glow discharge plasma for the surface alloying technique is diagnosed by optical emission spectrometry (OES). With CH4 as the feeding gas, Ne is obtained by comparing the Hβ spectrum ac...Electron density (Ne) in a glow discharge plasma for the surface alloying technique is diagnosed by optical emission spectrometry (OES). With CH4 as the feeding gas, Ne is obtained by comparing the Hβ spectrum according to the Stark broadening effect. It is noticed that Ne varies with the working pressures (30 Pa to 70 Pa) and cathode voltages (500 V to 1000 V), respectively. Due to an abnormal glow discharge, Ne is between 1. 71 × 10^15 /cm^3 to 6.64 × 10^15 /cm^3 and increases rapidly with working gas pressures and cathode voltages. The results show that OES is a useful method to measure the plasma parameters in a surface alloying glow discharge plasma.展开更多
The corrosion mechanism of 510L low alloy steel treated by acid-cleaned surface(ACS)and eco-pickled surface(EPS)techniques in three simulated solutions(S0:atmospheric environment;S1:soil environment;S2:industrial envi...The corrosion mechanism of 510L low alloy steel treated by acid-cleaned surface(ACS)and eco-pickled surface(EPS)techniques in three simulated solutions(S0:atmospheric environment;S1:soil environment;S2:industrial environment)and the influence of interaction between different corrosive anions on corrosion were investigated.The results show that the total corrosion rates of samples in three simulated solutions were in order of S2>S0>S1,which is simultaneously correlated with initial corrosion dissolution processes as well as after the formation of corrosion products.HCO3−will inhibit the initial corrosion owing to the formation of films,whereas HSO3−will accelerate the dissolutions of the matrix based on the synergistic action of HSO3−and Cl−.On the other hand,there is no significant difference in corrosion rates between the samples treated by ACS and EPS techniques.The EPS technique that is safe,reusable and environmentally friendly can be further widely used in future work.展开更多
We report a non-destructive characterization of planar two-dimensional (2D) photonic crystals (PhCs) made in silicon on insulator (SOI) wafers using ellipsometric or Fourier transformed infrared (FTIR) spectro...We report a non-destructive characterization of planar two-dimensional (2D) photonic crystals (PhCs) made in silicon on insulator (SOI) wafers using ellipsometric or Fourier transformed infrared (FTIR) spectroscope. At large wavelengths, devices behave as homogeneous isotropic materials defined by an effective filling factor. The experimental results related to the PhC limited dimensions confirm this characterization.展开更多
The Lundberg–Palmgren(L–P)fatigue life formula,as a statistical fatigue theory,has been widely used in the industry.However,its direct applicability is limited to the components treated by surface strengthening tech...The Lundberg–Palmgren(L–P)fatigue life formula,as a statistical fatigue theory,has been widely used in the industry.However,its direct applicability is limited to the components treated by surface strengthening technologies.Rolling contact fatigue tests and surface integrity measurements of American Iron and Steel Institute(AISI)9310 rollers with several surface treatments were performed to address this issue.Based on these results,a modified L–P fatigue model was proposed,enabling the consideration of surface modification including surface roughness,residual stress,and hardening introduced by different surface treatments.Compared with the original L–P fatigue formula,its results are more accurate for surface strengthened specimens.Furthermore,this method can assess the contact fatigue life of gears treated by surface strengthening techniques.展开更多
The Mo surface modified layer on titanium was obtained by the plasma surface alloying technique. The structure and composition of the Mo modified titanium were investigated by X-ray diffraction (XRD) and glow discha...The Mo surface modified layer on titanium was obtained by the plasma surface alloying technique. The structure and composition of the Mo modified titanium were investigated by X-ray diffraction (XRD) and glow discharge optical emission spectroscopy (GDOES). The Mo modified layer contains Mo coating on subsurface and diffusion layers between the subsurface and substrate. The Xray diffraction analysis of the Mo modified titanium reveals that the outmost surface of the Mo modified titanium is composed of pure Mo. The electrochemical corrosion performance of the Mo modified titanium in saliva was investigated and compared with that of titanium. The chemical corrosion performance of the Mo modified titanium in 37 ℃ saliva was investigated and compared with that of titanium. The experimental results indicated that self-corroding electric potentials and corrosion-rate of the Mo modified titanium were higher than that of titanium in saliva. Corrosion-rate of the Mo modified titanium was lower than that of titanium in 37 ℃ saliva.展开更多
The coupling of model batteries and surface-sensitive techniques provides an indispensable platform for interrogating the vital surface/interface processes in battery systems.Here,we report a sandwich-format nanopore-...The coupling of model batteries and surface-sensitive techniques provides an indispensable platform for interrogating the vital surface/interface processes in battery systems.Here,we report a sandwich-format nanopore-array model battery using an ultrathin graphite electrode and an anodized aluminum oxide(AAO)film.The porous framework of AAO regulates the contact pattern of the electrolyte with the graphite electrode from the inner side,while minimizing contamination on the outer surface.This model battery facilitates repetitive charge-discharge processes,where the graphite electrode is reversibly intercalated and deintercalated,and also allows for the in-situ characterizations of ion intercalation in the graphite electrode.The ion distribution profiles indicate that the intercalating Li ions accumulate in both the inner and outer surface regions of graphite,generating a high capacity of~455 mAh·g^(-1)(theory:372 mAh·g^(-1)).The surface enrichment presented herein provides new insights towards the mechanistic understanding of batteries and the rational design strategies.展开更多
N doped TiO2 (N-TiO2) coatings were obtained by oxidation of titanium nitride coatings, which were pre pared by the plasma surface alloying technique on stainless steel (SS). The microstructure of N-TiO2 coatings ...N doped TiO2 (N-TiO2) coatings were obtained by oxidation of titanium nitride coatings, which were pre pared by the plasma surface alloying technique on stainless steel (SS). The microstructure of N-TiO2 coatings was characterized by X-ray diffraction (XRD), glow discharge optical emission spectrometry (GDOES), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), respectively. Ball-on-disc sliding wear was applied to test and compare the tribological behaviors of the coatings and substrate. XRD patterns showed that anatase type TiO2 existed in the coatings after oxidation. GDOES showed that the resultant coatings had a layered structure, comprising of N-TiO2 layer at the top and a diffusion-type interface. Such a hybrid coatings system showed good adhesion with the substrate. According to XPS, residual N atoms partially occupied O atom sites in the TiO2 lattice. Uniform, continuous and compact coatings were observed by SEM images of coatings after oxidation. Under a load of 7.6 N, the coefficient of friction was in the range of 0.27--0.38 for the N-TiO2/Al2O3 systems and the wear rate of the coatings was only one-fourteenth of that for untreated 316L SS. N-TiO2 coatings displayed much better wear resistance and antifrietion performance than SS substrate.展开更多
Zr and its alloys have excellent mechanical properties as new structural material,but in specific application environment,its corrosion resistance still needs to be further explored.In this work,double glow plasma sur...Zr and its alloys have excellent mechanical properties as new structural material,but in specific application environment,its corrosion resistance still needs to be further explored.In this work,double glow plasma surface alloying technique was used for copperizing on pure Zr surface.Besides,X-ray diffraction(XRD),scanning electron microscope(SEM) and energy dispersion spectrum(EDS) were employed to characterize the samples.Furthermore,research was also conducted on the polarization curve of the samples in different solutions.Copperizing on surface can improve corrosion resistance of pure Zr in 3.5 % Na Cl and 0.5 moláL-1Na OH solutions.Especially in 0.5 moláL-1Na OH solution,the corrosion resistance can achieve significant improvement.However,copperizing has no influence on the improvement of corrosion resistance of pure Zr in 0.5 moláL-1H2SO4 solution.The results may provide new insight into way for improving the corrosion property of zirconium alloys.展开更多
This article presents a complete nonlinear controller design for a class of spin-stabilized canard-controlled projectiles.Uniformly ultimate boundedness and tracking are achieved,exploiting a heavily coupled,bounded u...This article presents a complete nonlinear controller design for a class of spin-stabilized canard-controlled projectiles.Uniformly ultimate boundedness and tracking are achieved,exploiting a heavily coupled,bounded uncertain and highly nonlinear model of longitudinal and lateral dynamics.In order to estimate unmeasurable states,an observer is proposed for an augmented multiple-input-multiple-output(MIMO) nonlinear system with an adaptive sliding mode term against the disturbances.Under the frame of a backstepping design,an adaptive sliding mode output-feedback dynamic surface control(DSC) approach is derived recursively by virtue of the estimated states.The DSC technique is adopted to overcome the problem of ‘‘explosion of complexity" and relieve the stress of the guidance loop.It is proven that all signals of the MIMO closed-loop system,including the observer and controller,are uniformly ultimately bounded,and the tracking errors converge to an arbitrarily small neighborhood of the origin.Simulation results for the observer and controller are provided to illustrate the feasibility and effectiveness of the proposed approach.展开更多
A multizone/multiblock coupled RANS equation solver is presented to numerically simulate the viscous flow around an appended submarine model at Reynolds number 1. E7. k-ε two equation turbulenc model together with wa...A multizone/multiblock coupled RANS equation solver is presented to numerically simulate the viscous flow around an appended submarine model at Reynolds number 1. E7. k-ε two equation turbulenc model together with wall function are used. The resulting finite difference equations are solved by SIMPLEC, ADI. The technique of rising up the bottom surface is presented to overcome radial contraction problem in Cartesian coordinate system. Benchmark numerical calculations have been compared with experimental data, the radial distribution of axial velocity on the propeller disk plane is 4. 63%.展开更多
Hydrothermal fabrication of selectively doped(Ag++ Pd3+) advanced ZnO nanomaterial has been carried out under mild pressure temperature conditions(autogeneous; 150°C).Gluconic acid has been used as a surfa...Hydrothermal fabrication of selectively doped(Ag++ Pd3+) advanced ZnO nanomaterial has been carried out under mild pressure temperature conditions(autogeneous; 150°C).Gluconic acid has been used as a surface modifier to effectively control the particle size and morphology of these ZnO nanoparticles. The experimental parameters were tuned to achieve optimum conditions for the synthesis of selectively doped ZnO nanomaterials with an experimental duration of 4 hr. These selectively doped ZnO nanoparticles were characterized using powder X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FT-IR), UV–Vis spectroscopy and scanning electron microscopy(SEM). The solar driven photocatalytic studies have been carried out for organic dyes, i.e., Procion MX-5B dye,Cibacron Brilliant Yellow dye, Indigo Carmine dye, separately and all three mixed, by using gluconic acid modified selectively doped advanced ZnO nanomaterial. The influence of catalyst, its concentration and initial dye concentration resulted in the photocatalytic efficiency of 89% under daylight.展开更多
基金Project(51371097)supported by the National Natural Science Foundation of ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Double glow plasma surface metallurgy technique was used to fabricate a Fe?Al?Cr?Nb alloyed layer onto the surface of the 45 steel. The microstructures and composition of th?eA Fl?eCr?Nb alloyed layer were analyzed by scanning electronic microscopy, X-ray diffraction and energy dispersive spectroscopy. The results indicate thatthe 20 μm alloyed layer is homogeneous and compact. The alloyed elements exhibit a gradient distribution along the cross section. Microhardness and nanoindentation tests imply that the surface hardness of the alloyed layer reaches HV 580, which is almost 2.8 times that of the substrate. Compared with the substrate, the alloyed layer has a much smaller displacement and a larger elastic modulus. According to the friction and wear tests at room temperature, the? FeAl?Cr?Nb alloyed layer has lower friction coefficient and less wear mass, implying that the Fe?Al?Cr?Nb alloyed layer can effectively improve the surface hardness and wear resistance of the substrate.
基金A Foundation for the Author of National Excellent Doctoral Dissertation of PR China(No.10021201)
文摘AIM: To prepare a new-type soft intraocular lens (IOL) that silicone intraocular lenses (IOLs) were modified by surface modification technique to assess IOLs biocompatibility. METHODS: With the technique of ion beam combined with low temperature and low pressure plasma, the surface characteristics of the IOLs including physical and optical properties were determined by the instruments of IOLs resolution, UV/VIS scanning spectrophotometer, contact angle measurement system, electron spectroscopy for chemical analysis (ESCA) and scanning electron microscope (SEM). RESULTS: The color of titanium (Ti) modified IOLs was light yellow and that of titanium nitride (TiN) modified IOLs was light brown. The absorptive degree of ultraviolet rays and the hydrophilicity of the surfaces of modified IOLs were increased, and appeared suitable chemical compositions. The resolution of unmodified and modified IOLs reached normal standard. The surfaces of unmodified and Ti-modified IOLs appeared uniform. The surfaces of TIN-modified IOLs presented fine porcelain structure. CONCLUSION: The optical properties of all IOLs and the surface morphology of the modified IOLs were not affected by modification processes. The surface properties of the modified IOLs were improved.
基金Project supported by the National Natural Science Foundation of China(Grant No.51601122)the 2019–2020 Intergovernmental Cooperation Projects in Science and Technology of the Ministry of Science and Technology,China(Grant No.CB02-03)+3 种基金the Science and Technology Major Project of Shanxi Province,China(Grant No.20181102013)the“331 Project”Engineering Research Center of Shanxi Province,China(Grant No.PT201801)the China Postdoctoral Science Foundation(Grant No.2017M620574)the Fund from the State Key Laboratory of Advanced Metal Materials,China(Grant No.2019-ZD02).
文摘TiAl-based alloys have received extensive attention recently due to their excellent properties. However, the weak oxidation resistance at temperatures higher than 800℃ can limit their further high-temperature structural applications.To improve the oxidation resistance of a high-Nb-content γ-TiAl alloy(Ti-45 Al-8.5 Nb, in units of at.%), a chromium(Cr)coating is prepared by using the plasma surface alloying technique, separately, at 800℃ and 1000℃. The x-ray diffraction(XRD) patterns reveal that an oxide surface layer consisting of Cr2O3, Al2O3, and TiO2 is produced on the Cr-coated Nb containing γ-TiAl substrates during the initial oxidation. However, the Cr2O3 is dominated in the oxide surface layer after being isothermally oxidized for 300 h. The oxidation kinetic curves are composed of a parabolic law stage(≤ 90 h) and a biquadratic law stage(≥ 90 h), fit by weight–gain curves. Due to diffusion in the fabrication process and oxidation process,the Cr-coated specimens have an adhesion force after being isothermally oxidized, specifically 69 N for a specimen after oxidation for 300 h. These results demonstrate that the Cr coating enhances the oxidation resistance and adhesion of a Ti-45 Al-8.5 Nb alloy, which may provide a new feasible scheme for designing oxidation protection layers.
文摘We present a 3D approach to numerical modeling of the borehole-surface electromagnetic (BSEM) method. The 3D electromagnetic response created by a vertical line current source in a layered medium is modeled using the 3D integral equation method. The modeling results are consistent with analytical solutions. 3D Born approximation inversion of BSEM data is also conducted for reservoir delineation. The inversion method is verified by a synthetic reservoir model.
文摘RE(NO_3)_3-HNO_3-P507-kerosene extraction system(RE=La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er, Tm,Yb,Lu,Y)was studied by the response surface technique.14 models for extracting single rare earth ele- ment in a broad range of acidity and initial rare earth concentration were obtained by using the stepwise regression method.Three-dimensional display of the response surface of the model of extracting Er^(3+)was showed as an example,which reveals clearly the dependence of distribution ratio upon both initial acidity and ini- tial rare earth concentration.
基金Supported by the National Fund for Fostering Talents of Basic Sciences of China
文摘We make use of the images from the Sloan Digital Sky Survey Stripe 82(Stripe 82) to present an analysis of r band surface brightness profiles and radial color gradients(g-r,u-r) in our sample of 111 nearby early-type galaxies(ETGs) .Thanks to the Stripe 82 images,each of which is co-added from about 50 single frames,we are able to pay special attention to the low-surface-brightness areas(LSB areas) of the galaxies.The LSB areas affect the Sérsic fittings and concentration indices by making both of the indices less than the typical values for ETGs.In the Sérsic fits to all the surface brightness profiles,we found some Sérsic indices that range from 1.5 to 2.5,much smaller than those of typical de Vaucouleur profiles and relatively close to those of exponential disks,and some others much larger than four but still with accurate fitting.Two galaxies cannot be fitted with a single Sérsic profile,but once we try double Sérsic profiles,the fittings are improved:one with a profile relatively close to the de Vaucouleur law in the inner area and a profile relatively close to an exponential law in the LSB area,the other with a nice fitting in the inner area but still having a failed fitting in the outer area.About 60%of the sample has negative color gradients(red-core) within 1.5Re,much more than the approximately 10%positive ones(blue-core) within the same radius.However,taking into account the LSB areas,we find that the color gradients are not necessarily monotonic:about one third of the red-core(or blue-core) galaxies have positive(or negative) color gradients in the outer areas. So LSB areas not only make ETGs’Sérsic profiles deviate from de Vaucouleur ones and shift to the disk end,but also reveal that quite a number of ETGs have opposite color gradients in inner and outer areas.These outcomes remind us of the necessity of double-Sérsic fitting.These LSB phenomena may be interpreted by mergers and thus have different metallicity in the outer areas.Isophotal parameters are also discussed briefly in this paper with the following conclusion:there are more disky nearby ETGs that are identified than boxy ones.
基金supported by National Steel Union Foundation of China (No.50374050)
文摘Electron density (Ne) in a glow discharge plasma for the surface alloying technique is diagnosed by optical emission spectrometry (OES). With CH4 as the feeding gas, Ne is obtained by comparing the Hβ spectrum according to the Stark broadening effect. It is noticed that Ne varies with the working pressures (30 Pa to 70 Pa) and cathode voltages (500 V to 1000 V), respectively. Due to an abnormal glow discharge, Ne is between 1. 71 × 10^15 /cm^3 to 6.64 × 10^15 /cm^3 and increases rapidly with working gas pressures and cathode voltages. The results show that OES is a useful method to measure the plasma parameters in a surface alloying glow discharge plasma.
基金supported by Key Scientific Research Project in Shanxi Province(Grant Nos.202003D111001 and 202102050201010)Fundamental Research Program of Shanxi Province(Grant No.202103021223293)+3 种基金National Natural Science Foundation of China(Grant No.52071227)Scientific Research Fund of Taiyuan University of Science and Technology(Grant No.20202044)Award Fund for Outstanding Doctors in Shanxi Province(Grant No.20212041)Postgraduate Education Innovation Project of Shanxi Province(Grant Nos.2022Y686 and 2022Y684).
文摘The corrosion mechanism of 510L low alloy steel treated by acid-cleaned surface(ACS)and eco-pickled surface(EPS)techniques in three simulated solutions(S0:atmospheric environment;S1:soil environment;S2:industrial environment)and the influence of interaction between different corrosive anions on corrosion were investigated.The results show that the total corrosion rates of samples in three simulated solutions were in order of S2>S0>S1,which is simultaneously correlated with initial corrosion dissolution processes as well as after the formation of corrosion products.HCO3−will inhibit the initial corrosion owing to the formation of films,whereas HSO3−will accelerate the dissolutions of the matrix based on the synergistic action of HSO3−and Cl−.On the other hand,there is no significant difference in corrosion rates between the samples treated by ACS and EPS techniques.The EPS technique that is safe,reusable and environmentally friendly can be further widely used in future work.
文摘We report a non-destructive characterization of planar two-dimensional (2D) photonic crystals (PhCs) made in silicon on insulator (SOI) wafers using ellipsometric or Fourier transformed infrared (FTIR) spectroscope. At large wavelengths, devices behave as homogeneous isotropic materials defined by an effective filling factor. The experimental results related to the PhC limited dimensions confirm this characterization.
基金supported the National Natural Science Foundation of China(No.52275050)Shaanxi Key Laboratory of Gear Transmission Open Program(No.SKLGT-2022-005).
文摘The Lundberg–Palmgren(L–P)fatigue life formula,as a statistical fatigue theory,has been widely used in the industry.However,its direct applicability is limited to the components treated by surface strengthening technologies.Rolling contact fatigue tests and surface integrity measurements of American Iron and Steel Institute(AISI)9310 rollers with several surface treatments were performed to address this issue.Based on these results,a modified L–P fatigue model was proposed,enabling the consideration of surface modification including surface roughness,residual stress,and hardening introduced by different surface treatments.Compared with the original L–P fatigue formula,its results are more accurate for surface strengthened specimens.Furthermore,this method can assess the contact fatigue life of gears treated by surface strengthening techniques.
基金Funded by the ‘863" Program(2007AA03Z521)the National Natural Science Foundation of China (No.50771070)the Foundation for Re-turned Overseas Scholars of department of human research and social security of Shanxi Province
文摘The Mo surface modified layer on titanium was obtained by the plasma surface alloying technique. The structure and composition of the Mo modified titanium were investigated by X-ray diffraction (XRD) and glow discharge optical emission spectroscopy (GDOES). The Mo modified layer contains Mo coating on subsurface and diffusion layers between the subsurface and substrate. The Xray diffraction analysis of the Mo modified titanium reveals that the outmost surface of the Mo modified titanium is composed of pure Mo. The electrochemical corrosion performance of the Mo modified titanium in saliva was investigated and compared with that of titanium. The chemical corrosion performance of the Mo modified titanium in 37 ℃ saliva was investigated and compared with that of titanium. The experimental results indicated that self-corroding electric potentials and corrosion-rate of the Mo modified titanium were higher than that of titanium in saliva. Corrosion-rate of the Mo modified titanium was lower than that of titanium in 37 ℃ saliva.
基金supported by the National Key Research and Development(R&D)Program of China(No.2021YFA1502800)the National Natural Science Foundation of China(Nos.21825203,22288201,and 91945302)+2 种基金Photon Science Center for Carbon Neutrality,LiaoNing Revitalization Talents Program(No.XLYC1902117)the Dalian National Laboratory for Clean Energy(DNL)Cooperation Fund(No.DNL201907)the Youth Innovation Fund of Dalian Institute of Chemical Physics(No.DICP I202125).
文摘The coupling of model batteries and surface-sensitive techniques provides an indispensable platform for interrogating the vital surface/interface processes in battery systems.Here,we report a sandwich-format nanopore-array model battery using an ultrathin graphite electrode and an anodized aluminum oxide(AAO)film.The porous framework of AAO regulates the contact pattern of the electrolyte with the graphite electrode from the inner side,while minimizing contamination on the outer surface.This model battery facilitates repetitive charge-discharge processes,where the graphite electrode is reversibly intercalated and deintercalated,and also allows for the in-situ characterizations of ion intercalation in the graphite electrode.The ion distribution profiles indicate that the intercalating Li ions accumulate in both the inner and outer surface regions of graphite,generating a high capacity of~455 mAh·g^(-1)(theory:372 mAh·g^(-1)).The surface enrichment presented herein provides new insights towards the mechanistic understanding of batteries and the rational design strategies.
基金Item Sponsored by National Natural Science Foundation of China(50771070)Project Innovation of Graduate Students of Shanxi Province of China(20093038)
文摘N doped TiO2 (N-TiO2) coatings were obtained by oxidation of titanium nitride coatings, which were pre pared by the plasma surface alloying technique on stainless steel (SS). The microstructure of N-TiO2 coatings was characterized by X-ray diffraction (XRD), glow discharge optical emission spectrometry (GDOES), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), respectively. Ball-on-disc sliding wear was applied to test and compare the tribological behaviors of the coatings and substrate. XRD patterns showed that anatase type TiO2 existed in the coatings after oxidation. GDOES showed that the resultant coatings had a layered structure, comprising of N-TiO2 layer at the top and a diffusion-type interface. Such a hybrid coatings system showed good adhesion with the substrate. According to XPS, residual N atoms partially occupied O atom sites in the TiO2 lattice. Uniform, continuous and compact coatings were observed by SEM images of coatings after oxidation. Under a load of 7.6 N, the coefficient of friction was in the range of 0.27--0.38 for the N-TiO2/Al2O3 systems and the wear rate of the coatings was only one-fourteenth of that for untreated 316L SS. N-TiO2 coatings displayed much better wear resistance and antifrietion performance than SS substrate.
基金financially supported by the National Basic Research Program of China (No.2013CB733000)the National Natural Science Foundation of China (Nos.51271161,51271162 and 51434008)
文摘Zr and its alloys have excellent mechanical properties as new structural material,but in specific application environment,its corrosion resistance still needs to be further explored.In this work,double glow plasma surface alloying technique was used for copperizing on pure Zr surface.Besides,X-ray diffraction(XRD),scanning electron microscope(SEM) and energy dispersion spectrum(EDS) were employed to characterize the samples.Furthermore,research was also conducted on the polarization curve of the samples in different solutions.Copperizing on surface can improve corrosion resistance of pure Zr in 3.5 % Na Cl and 0.5 moláL-1Na OH solutions.Especially in 0.5 moláL-1Na OH solution,the corrosion resistance can achieve significant improvement.However,copperizing has no influence on the improvement of corrosion resistance of pure Zr in 0.5 moláL-1H2SO4 solution.The results may provide new insight into way for improving the corrosion property of zirconium alloys.
基金supported by the National Natural Science Foundation of China(No.11532002)
文摘This article presents a complete nonlinear controller design for a class of spin-stabilized canard-controlled projectiles.Uniformly ultimate boundedness and tracking are achieved,exploiting a heavily coupled,bounded uncertain and highly nonlinear model of longitudinal and lateral dynamics.In order to estimate unmeasurable states,an observer is proposed for an augmented multiple-input-multiple-output(MIMO) nonlinear system with an adaptive sliding mode term against the disturbances.Under the frame of a backstepping design,an adaptive sliding mode output-feedback dynamic surface control(DSC) approach is derived recursively by virtue of the estimated states.The DSC technique is adopted to overcome the problem of ‘‘explosion of complexity" and relieve the stress of the guidance loop.It is proven that all signals of the MIMO closed-loop system,including the observer and controller,are uniformly ultimately bounded,and the tracking errors converge to an arbitrarily small neighborhood of the origin.Simulation results for the observer and controller are provided to illustrate the feasibility and effectiveness of the proposed approach.
文摘A multizone/multiblock coupled RANS equation solver is presented to numerically simulate the viscous flow around an appended submarine model at Reynolds number 1. E7. k-ε two equation turbulenc model together with wall function are used. The resulting finite difference equations are solved by SIMPLEC, ADI. The technique of rising up the bottom surface is presented to overcome radial contraction problem in Cartesian coordinate system. Benchmark numerical calculations have been compared with experimental data, the radial distribution of axial velocity on the propeller disk plane is 4. 63%.
基金supported by University Grant Commission under University with Potential for excellence Programme (UPE), University of Mysore
文摘Hydrothermal fabrication of selectively doped(Ag++ Pd3+) advanced ZnO nanomaterial has been carried out under mild pressure temperature conditions(autogeneous; 150°C).Gluconic acid has been used as a surface modifier to effectively control the particle size and morphology of these ZnO nanoparticles. The experimental parameters were tuned to achieve optimum conditions for the synthesis of selectively doped ZnO nanomaterials with an experimental duration of 4 hr. These selectively doped ZnO nanoparticles were characterized using powder X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FT-IR), UV–Vis spectroscopy and scanning electron microscopy(SEM). The solar driven photocatalytic studies have been carried out for organic dyes, i.e., Procion MX-5B dye,Cibacron Brilliant Yellow dye, Indigo Carmine dye, separately and all three mixed, by using gluconic acid modified selectively doped advanced ZnO nanomaterial. The influence of catalyst, its concentration and initial dye concentration resulted in the photocatalytic efficiency of 89% under daylight.