ZrSiN thin films are synthesized by using plasma focus through various numbers of focus shots （10, 20, and 30）, with samples placed at 9 cm away from the tip of the anode. Crystal structures, surface morphologies, a...ZrSiN thin films are synthesized by using plasma focus through various numbers of focus shots （10, 20, and 30）, with samples placed at 9 cm away from the tip of the anode. Crystal structures, surface morphologies, and elemental compositions of ZrSiN films are characterized by an X-ray diffractometer （XRD） and scanning electron microscope （SEM） attached with energy dispersive X-ray spectroscopy （EDS）. XRD patterns confirm the formations of polycrystalline ZrSiN films. Crystallinity of nitride increases with the increase of focus shot number. The average crystallite size of zirconium nitride increases from 27 ± 3 nm to 73±8 nm and microstrain decreases from 2.28 to 1.0 with the increase of the focus shot number. SEM results exhibit the formations of granular and oval-shaped microstructures, depending on the number of focus shots. EDS results confirm the presences of silicon, zirconium, nitrogen, and oxygen in the composite films. The content values of Zr and N in the composite films increase with the increase of the focus shot number.展开更多
The Al/a-C nanocomposite thin films are synthesized on Si substrates using a dense plasma focus device with alu- minum fitted anode and operating with CH4/Ar admixture. X-ray diffractometer results confirm the formati...The Al/a-C nanocomposite thin films are synthesized on Si substrates using a dense plasma focus device with alu- minum fitted anode and operating with CH4/Ar admixture. X-ray diffractometer results confirm the formation of metallic crystalline Al phases using different numbers of focus shots. Raman analyses show the formation of D and G peaks for all thin film samples, confirming the presence of a-C in the nanocomposite thin films. The formation of Al/a-C nanocomposite thin films is further confirmed using X-ray photoelectron spectroscopy analysis. The scanning electron microscope results show that the deposited thin films consist of nanoparticles and their agglomerates. The sizes of th agglomerates increase with increasing numbers of focus deposition shots. The nanoindentation results show the variations in hardness and elastic modulus values of nanocomposite thin film with increasing the number of focus shots. Maximum values of hardness and elastic modulus of the composite thin film prepared using 20 focus shots are found to be about 10.7 GPa and 189.2 GPa, respectively.展开更多
A 2.3 kJ Mather type pulsed plasma focus device was used for the synthesis of a TiN/a-Si3N4 thin film at room temperature. The film was characterized using X-ray diffraction （XRD）, X-ray photoelectron spectroscopy ...A 2.3 kJ Mather type pulsed plasma focus device was used for the synthesis of a TiN/a-Si3N4 thin film at room temperature. The film was characterized using X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, scanning electron microscopy （SEM）, and atomic force microscopy （AFM）. The XRD pattern confirms the growth of polycrystalline TiN thin film. The XPS results indicate that the synthesized film is non-stoichiometric and contains titanium nitride, silicon nitride, and a phase of silicon oxy-nitride. The SEM and AFM results reveal that the surface of the synthesized film is quite smooth with 0.59 nm roughness （root-mean-square）.展开更多
We investigate the effects of 2 MeV Ni+ ion beam irradiation with various fluence ranging from 15 × 1011 to 60 × 1014 ions/cm2 on the surface, structural and mechanical properties of Cu-Zn alloy. The modific...We investigate the effects of 2 MeV Ni+ ion beam irradiation with various fluence ranging from 15 × 1011 to 60 × 1014 ions/cm2 on the surface, structural and mechanical properties of Cu-Zn alloy. The modification in target properties after irradiation is confirmed by using various characterization techniques viz. SEM, XRD, UTM and Vickers micro-hardness tester. The SEM results illustrate the formation of nano sized craters with different diameters. Their average diameter decreases from 190 nm to 90 nm by increasing ion fluence. The XRD analysis of irradiated targets reveals that Ni+ ion irradiation enhances the growth of (111) phase and its peak position varies due to ion induced tensile stresses in target matrix. Tensile and Vickers micro-hardness tests verify the mechanical properties of Cu-Zn alloy reduce monotonically upon irradiation. Various mechanisms such as generation, recombination, augmentation and annihilation of ion induced defects are responsible for this reduction. Understanding the relationships between various modified properties of irradiated target is essential for growing new advanced material by irradiation.展开更多
Several aspects of the internal structure of pseudoscalar mesons,accessible through generalized parton distri-butions in their zero-skewness limit,are examined.These include electromagnetic and gravitational form fact...Several aspects of the internal structure of pseudoscalar mesons,accessible through generalized parton distri-butions in their zero-skewness limit,are examined.These include electromagnetic and gravitational form factors related to charge and mass densities;and distributions in the impact parameter space.To this end,we employ an algebraically viable framework that is based upon the valence-quark generalized parton distribution expressed explicitly in terms of the associated distribution function and a profile function that governs the off-forward dynamics.The predominantly analytical nature of this scheme yields several algebraic results and relations while also facilitating the exploration of insightful limiting cases.With a suitable input distribution function,guided either by experiment or theory,and with an appropriate choice of the profile function,it is possible to provide testable predictions for spatial distributions of valence quarks inside pseudoscalar mesons.When comparison is possible,these predictions align well with existing experimental data as well as the findings of reliable theoretical approaches and lattice QCD.展开更多
Effects of deposition angle and axial distance on the structural and mechanical properties of niobium nitride syn- thesized by a dense plasma focus （DPF） system are studied. The x-ray diffraction （XRD） confirms th...Effects of deposition angle and axial distance on the structural and mechanical properties of niobium nitride syn- thesized by a dense plasma focus （DPF） system are studied. The x-ray diffraction （XRD） confirms that the deposition parameters affect the growth of multi-phase niobium nitride. Scanning electron microscopy （SEM） shows the granular surface morphology with strong thermally assisted coagulation effects observed at the 5-cm axial distance. The non-porous granular morphology observed at the 9-cm distance along the anode axis is different from those observed at deposition angles of 10° and 20°. Energy dispersive x-ray （EDX） spectroscopy reveals the maximum nitrogen content at the shortest （5 cm） axial position. Atomic force microscopy （AFM） exhibits that the roughness of coated films varies for coatings synthesized at different axial and angular positions, and the Vickers micro-hardness test shows that a maximum hardness value is （08.44 ±0.01） GPa for niobium nitride synthesized at 5-cm axial distance, which is about 500% more than that of a virgin sample.展开更多
Brass targets were irradiated with various laser pulses of Excimer laser ranging from 1200 to 3000 for constant fluence of 3.4 J/cm2 in oxygen atmosphere (100 Torr). The surface morphology and crystallographic analyse...Brass targets were irradiated with various laser pulses of Excimer laser ranging from 1200 to 3000 for constant fluence of 3.4 J/cm2 in oxygen atmosphere (100 Torr). The surface morphology and crystallographic analyses were performed by using Scanning Electron Microscope (SEM) and X-Ray Diffractometer (XRD). SEM analysis reveals the formation of laser-induced micro-sized cavities, bumps, cones and wave-like ridges with non-uniform shape and density distribution. These features are formed for all number of pulses;however with increasing number of pulses from 1200 to 2400, the density of cavities decreases whereas, the wave-like ridges become more pronounced and bump-formation is vanished. For maximum number of 3000 shots, the appearance of cones and wave-like ridges becomes diffusive, whereas the density and size of cavities increase again. XRD analysis demonstrates that no new phases are formed in irradiated brass. However, the change in peak intensity along with lower and higher angle shifting is observed which is attributed to generation of laser induced stresses. The Yield Stress (YS), Ultimate Tensile Strength (UTS) as well as Microhardness increase monotonically with increasing number of laser pulses.展开更多
Clear windows onto emergent hadron mass(EHM)and modulations thereof by Higgs boson interactions are provided by observable measures of pion and kaon structure,many of which are accessible via generalised parton distri...Clear windows onto emergent hadron mass(EHM)and modulations thereof by Higgs boson interactions are provided by observable measures of pion and kaon structure,many of which are accessible via generalised parton distributions(GPDs).Beginning with algebraic GPD Ansätze,constrained entirely by hadron-scaleπand K valence-parton distribution functions(DFs),in whose forms both EHM and Higgs boson influences are manifest,numerous illustrations are provided.They include the properties of electromagnetic form factors,impact parameter space GPDs,gravitational form factors and associated pressure profiles,and the character and consequences of allorders evolution.The analyses predict that mass-squared gravitational form factors are stiffer than electromagnetic form factors;reveal that K pressure profiles are tighter than profiles,with both mesons sustaining near-core pressures at magnitudes similar to that expected at the core of neutron stars;deliver parameter-free predictions for and K valence,glue,and sea GPDs at the resolving scale l=2GeV;and predict that at this scale the fraction of meson mass-squared carried by glue and sea combined matches that lodged with the valence degrees-of-freedom,with a similar statement holding for mass-squared radii.展开更多
Using lattice configurations for quantum chromodynamics(QCD)generated with three domain-wall fermions at a physical pion mass,we obtain a parameter-free prediction of QCD’s renormalisation-group-invariant process-ind...Using lattice configurations for quantum chromodynamics(QCD)generated with three domain-wall fermions at a physical pion mass,we obtain a parameter-free prediction of QCD’s renormalisation-group-invariant process-independent effective charge,α^(k2).Owing to the dynamical breaking of scale invariance,evident in the emergence of a gluon mass-scale,m0=0.43(1)GeV,this coupling saturates at infrared momenta:α^(0)/π=0.97(4).Amongst other things:α^(k2)is almost identical to the process-dependent(PD)effective charge defined via the Bjorken sum rule;and also that PD charge which,employed in the one-loop evolution equations,delivers agreement between pion parton distribution functions computed at the hadronic scale and experiment.The diversity of unifying roles played byα^(k^2)suggests that it is a strong candidate for that object which represents the interaction strength in QCD at any given momentum scale;and its properties support a conclusion that QCD is a mathematically well-defined quantum field theory in four dimensions.展开更多
基金supported by the National Project for Research for University,the Higher Education Commission(HEC),Pakistan
文摘ZrSiN thin films are synthesized by using plasma focus through various numbers of focus shots （10, 20, and 30）, with samples placed at 9 cm away from the tip of the anode. Crystal structures, surface morphologies, and elemental compositions of ZrSiN films are characterized by an X-ray diffractometer （XRD） and scanning electron microscope （SEM） attached with energy dispersive X-ray spectroscopy （EDS）. XRD patterns confirm the formations of polycrystalline ZrSiN films. Crystallinity of nitride increases with the increase of focus shot number. The average crystallite size of zirconium nitride increases from 27 ± 3 nm to 73±8 nm and microstrain decreases from 2.28 to 1.0 with the increase of the focus shot number. SEM results exhibit the formations of granular and oval-shaped microstructures, depending on the number of focus shots. EDS results confirm the presences of silicon, zirconium, nitrogen, and oxygen in the composite films. The content values of Zr and N in the composite films increase with the increase of the focus shot number.
文摘The Al/a-C nanocomposite thin films are synthesized on Si substrates using a dense plasma focus device with alu- minum fitted anode and operating with CH4/Ar admixture. X-ray diffractometer results confirm the formation of metallic crystalline Al phases using different numbers of focus shots. Raman analyses show the formation of D and G peaks for all thin film samples, confirming the presence of a-C in the nanocomposite thin films. The formation of Al/a-C nanocomposite thin films is further confirmed using X-ray photoelectron spectroscopy analysis. The scanning electron microscope results show that the deposited thin films consist of nanoparticles and their agglomerates. The sizes of th agglomerates increase with increasing numbers of focus deposition shots. The nanoindentation results show the variations in hardness and elastic modulus values of nanocomposite thin film with increasing the number of focus shots. Maximum values of hardness and elastic modulus of the composite thin film prepared using 20 focus shots are found to be about 10.7 GPa and 189.2 GPa, respectively.
文摘A 2.3 kJ Mather type pulsed plasma focus device was used for the synthesis of a TiN/a-Si3N4 thin film at room temperature. The film was characterized using X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, scanning electron microscopy （SEM）, and atomic force microscopy （AFM）. The XRD pattern confirms the growth of polycrystalline TiN thin film. The XPS results indicate that the synthesized film is non-stoichiometric and contains titanium nitride, silicon nitride, and a phase of silicon oxy-nitride. The SEM and AFM results reveal that the surface of the synthesized film is quite smooth with 0.59 nm roughness （root-mean-square）.
文摘We investigate the effects of 2 MeV Ni+ ion beam irradiation with various fluence ranging from 15 × 1011 to 60 × 1014 ions/cm2 on the surface, structural and mechanical properties of Cu-Zn alloy. The modification in target properties after irradiation is confirmed by using various characterization techniques viz. SEM, XRD, UTM and Vickers micro-hardness tester. The SEM results illustrate the formation of nano sized craters with different diameters. Their average diameter decreases from 190 nm to 90 nm by increasing ion fluence. The XRD analysis of irradiated targets reveals that Ni+ ion irradiation enhances the growth of (111) phase and its peak position varies due to ion induced tensile stresses in target matrix. Tensile and Vickers micro-hardness tests verify the mechanical properties of Cu-Zn alloy reduce monotonically upon irradiation. Various mechanisms such as generation, recombination, augmentation and annihilation of ion induced defects are responsible for this reduction. Understanding the relationships between various modified properties of irradiated target is essential for growing new advanced material by irradiation.
基金supported by the Spanish MICINN grant PID2022-140440NB-C22the regional Andalusian project P18-FR-5057+3 种基金the Coordinación de la Investigación Científica of the Universidad Michoacana de San Nicolás de Hidalgo,Morelia,Mexico,Grant No.4.10the Consejo Nacional de Humanidades,Ciencias y Tecnologías,Mexico,project CBF2023-2024-3544the Beatriz-Galindo support during his current scientific stay at the University of Huelva,Huelva,Spainthe Chair d'excellence within the program d'Alembert supporting a visiting professorship in the Universitéde Paris-Saclay,France。
文摘Several aspects of the internal structure of pseudoscalar mesons,accessible through generalized parton distri-butions in their zero-skewness limit,are examined.These include electromagnetic and gravitational form factors related to charge and mass densities;and distributions in the impact parameter space.To this end,we employ an algebraically viable framework that is based upon the valence-quark generalized parton distribution expressed explicitly in terms of the associated distribution function and a profile function that governs the off-forward dynamics.The predominantly analytical nature of this scheme yields several algebraic results and relations while also facilitating the exploration of insightful limiting cases.With a suitable input distribution function,guided either by experiment or theory,and with an appropriate choice of the profile function,it is possible to provide testable predictions for spatial distributions of valence quarks inside pseudoscalar mesons.When comparison is possible,these predictions align well with existing experimental data as well as the findings of reliable theoretical approaches and lattice QCD.
文摘Effects of deposition angle and axial distance on the structural and mechanical properties of niobium nitride syn- thesized by a dense plasma focus （DPF） system are studied. The x-ray diffraction （XRD） confirms that the deposition parameters affect the growth of multi-phase niobium nitride. Scanning electron microscopy （SEM） shows the granular surface morphology with strong thermally assisted coagulation effects observed at the 5-cm axial distance. The non-porous granular morphology observed at the 9-cm distance along the anode axis is different from those observed at deposition angles of 10° and 20°. Energy dispersive x-ray （EDX） spectroscopy reveals the maximum nitrogen content at the shortest （5 cm） axial position. Atomic force microscopy （AFM） exhibits that the roughness of coated films varies for coatings synthesized at different axial and angular positions, and the Vickers micro-hardness test shows that a maximum hardness value is （08.44 ±0.01） GPa for niobium nitride synthesized at 5-cm axial distance, which is about 500% more than that of a virgin sample.
文摘Brass targets were irradiated with various laser pulses of Excimer laser ranging from 1200 to 3000 for constant fluence of 3.4 J/cm2 in oxygen atmosphere (100 Torr). The surface morphology and crystallographic analyses were performed by using Scanning Electron Microscope (SEM) and X-Ray Diffractometer (XRD). SEM analysis reveals the formation of laser-induced micro-sized cavities, bumps, cones and wave-like ridges with non-uniform shape and density distribution. These features are formed for all number of pulses;however with increasing number of pulses from 1200 to 2400, the density of cavities decreases whereas, the wave-like ridges become more pronounced and bump-formation is vanished. For maximum number of 3000 shots, the appearance of cones and wave-like ridges becomes diffusive, whereas the density and size of cavities increase again. XRD analysis demonstrates that no new phases are formed in irradiated brass. However, the change in peak intensity along with lower and higher angle shifting is observed which is attributed to generation of laser induced stresses. The Yield Stress (YS), Ultimate Tensile Strength (UTS) as well as Microhardness increase monotonically with increasing number of laser pulses.
基金Supported by National Natural Science Foundation of China(12135007,11805097)Jiangsu Provincial Natural Science Foundation of China(BK20180323)+2 种基金Spanish Ministry of Science and Innovation(MICINN)(PID2019-107844GB-C22)Junta de Andalucía(P18-FR-5057,UHU-1264517)University of Huelva(EPIT-2019)。
文摘Clear windows onto emergent hadron mass(EHM)and modulations thereof by Higgs boson interactions are provided by observable measures of pion and kaon structure,many of which are accessible via generalised parton distributions(GPDs).Beginning with algebraic GPD Ansätze,constrained entirely by hadron-scaleπand K valence-parton distribution functions(DFs),in whose forms both EHM and Higgs boson influences are manifest,numerous illustrations are provided.They include the properties of electromagnetic form factors,impact parameter space GPDs,gravitational form factors and associated pressure profiles,and the character and consequences of allorders evolution.The analyses predict that mass-squared gravitational form factors are stiffer than electromagnetic form factors;reveal that K pressure profiles are tighter than profiles,with both mesons sustaining near-core pressures at magnitudes similar to that expected at the core of neutron stars;deliver parameter-free predictions for and K valence,glue,and sea GPDs at the resolving scale l=2GeV;and predict that at this scale the fraction of meson mass-squared carried by glue and sea combined matches that lodged with the valence degrees-of-freedom,with a similar statement holding for mass-squared radii.
文摘Using lattice configurations for quantum chromodynamics(QCD)generated with three domain-wall fermions at a physical pion mass,we obtain a parameter-free prediction of QCD’s renormalisation-group-invariant process-independent effective charge,α^(k2).Owing to the dynamical breaking of scale invariance,evident in the emergence of a gluon mass-scale,m0=0.43(1)GeV,this coupling saturates at infrared momenta:α^(0)/π=0.97(4).Amongst other things:α^(k2)is almost identical to the process-dependent(PD)effective charge defined via the Bjorken sum rule;and also that PD charge which,employed in the one-loop evolution equations,delivers agreement between pion parton distribution functions computed at the hadronic scale and experiment.The diversity of unifying roles played byα^(k^2)suggests that it is a strong candidate for that object which represents the interaction strength in QCD at any given momentum scale;and its properties support a conclusion that QCD is a mathematically well-defined quantum field theory in four dimensions.
