Mg alloy matrix composites reinforced with short carbon fibers(C_(sf)/Mg)are considered as potential candidates for integrated structural-functional electronic parts that satisfy the requirements of lightweight,excell...Mg alloy matrix composites reinforced with short carbon fibers(C_(sf)/Mg)are considered as potential candidates for integrated structural-functional electronic parts that satisfy the requirements of lightweight,excellent mechanical properties,and heat dissipation.However,the different characteristics of C_(sf)and Mg alloy make the interface a critical issue affecting the synergistic improvement of thermal and mechanical properties of the composites.Here,Cu coating with different thicknesses is introduced to modify the C_(sf)/Mg interface,so as to simultaneously enhance the thermal and mechanical performances,which can combine the advantages of coating modification and matrix alloying.Results reveal that thermal diffusivity(TD)of 3-C_(sf)-Cu/Mg composites is as high as 22.12 mm^(2)/s and an enhancement of 52.97%is achieved compared with C_(sf)/Mg composites,as well as 16.3%enhancement of ultimate compressive strength(UCS)in the longitudinal direction,8.84%improvement of UCS in the transverse direction,and 53.08%increasement of ultimate tensile strength(UTS).Such improvement can be ascribed to the formation of intermetallic compounds.The formation of intermetallic compounds can not only effectively alleviate the lattice distortion of the matrix and decrease interfacial thermal resistance,but also bear the loads.Our work is of great significance for designing C_(sf)/Mg composites with integrated structure and function.展开更多
To advance the understanding of the corrosion behavior of stainless steel bellows in marine atmospheric environments and enhance the precision of service life predictions,this study employs finite element simulations ...To advance the understanding of the corrosion behavior of stainless steel bellows in marine atmospheric environments and enhance the precision of service life predictions,this study employs finite element simulations to investigate the pitting corrosion rates and pit morphologies of bellows peaks and troughs under varying electrolyte film thicknesses.The model incorporates localized electrochemical reactions,oxygen concentration,and homogeneous solution reactions.For improved computational accuracy,the fitted polarization curve data were directly applied as nonlinear boundary conditions on the electrode surface via interpolation functions.Simulation results reveal that the peak regions exhibit faster corrosion rates than the trough regions.With increasing electrolyte film thickness(from 10μm to 500μm),corrosion rates at both peaks and troughs decrease progressively,and after 120 hours of simulation,the maximum corrosion rate at the peaks declines from 0.720 mm/a to 0.130 mm/a,and at the troughs from 0.520 mm/a to 0.120 mm/a,with the disparity in corrosion rates diminishing over time.Furthermore,as corrosion progresses,pits propagate deeper into the substrate,exhibiting both vertical penetration and lateral expansion along the passive film interface,ultimately breaching the substrate.This research offers valuable insights into designing corrosion mitigation strategies for stainless steel bellows in marine environments.展开更多
In this paper,a meshfree Jacobi point interpolation(MJPI)approach for the dynamic analysis of sandwich laminated conical and cylindrical shells with varying thickness is presented.The theoretical formulations for sand...In this paper,a meshfree Jacobi point interpolation(MJPI)approach for the dynamic analysis of sandwich laminated conical and cylindrical shells with varying thickness is presented.The theoretical formulations for sandwich laminated shells with varying thickness are established using the modified variational principle within the framework of first-order shear deformation theory(FSDT).The displacement components of the sandwich shell are expanded using the MJPI shape function and Fourier series in the meridional and circumferential directions,respectively.The accuracy and reliability of the proposed MJPI shape function are validated against numerical results from published literature and the commercial simulation tool Abaqus.Finally,the effects of different parameters such as thickness gradient,thickness power index and boundary condition on the free vibration and dynamic response of the sandwich laminated shell are investigated.展开更多
The yield ratios of neutron-proton(R(n/p))and^(3)H-^(3)He(R(^(3)H∕^(3)He))with reduced rapidity from 0 to 0.5 were simulated at 50 MeV/u even-even ^(36−56)Ca+^(40)Ca,even-even ^(48−78)Ni+^(58)Ni,and ^(100−139)Sn(ever...The yield ratios of neutron-proton(R(n/p))and^(3)H-^(3)He(R(^(3)H∕^(3)He))with reduced rapidity from 0 to 0.5 were simulated at 50 MeV/u even-even ^(36−56)Ca+^(40)Ca,even-even ^(48−78)Ni+^(58)Ni,and ^(100−139)Sn(every third isotopes)+112 Sn for full reduced impact parameters using the isospin-dependent quantum molecular dynamics(IQMD)model.The neutron and proton density distributions and root-mean-square radii of the reaction systems were obtained using the Skyrme-Hartree-Fock model,which was used for the phase space initialization of the projectile and target in IQMD.We defined the unified neutron skin thickness asΔRnp=<r^(2)>^(1∕2) n−<r^(2)>^(1∕2)p,which was negative for neutron-deficient nuclei.The unifiedΔRnp values for nuclei with the same relative neutron excess from different isotopic chains were nearly equal,except for extreme neutron-rich isotopes,which is a type of scaling behavior.The yield ratios of the three isotopic chain-induced reactions,which depended on the reduced impact parameter and unified neutron skin thickness,were studied.The results showed that both R(n/p)and R(^(3)H∕^(3)He)decreased with a reduced impact parameter for extreme neutron-deficient isotopes;however,they increased with reduced impact parameters for extreme neutron-rich isotopes,and increased with theΔRnp of the projectiles for all reduced impact parameters.In addition,a scaling phenomenon was observed betweenΔR np and the yield ratios in peripheral colli-sions from different isotopic chain projectiles(except for extreme neutron-rich isotopes).Thus,R(n/p)and R(^(3)H∕^(3)He)from peripheral collisions were suggested as experimental probes for extracting the neutron or proton skin thicknesses of non-extreme neutron-rich nuclei from different isotopic chains.展开更多
Precise knowledge of the nuclear symmetry energy can be tentatively calibrated using multimessenger constraints.The neutron skin thickness of a heavy nucleus is one of the most sensitive indicators for probing the iso...Precise knowledge of the nuclear symmetry energy can be tentatively calibrated using multimessenger constraints.The neutron skin thickness of a heavy nucleus is one of the most sensitive indicators for probing the isovector components of effective interactions in asymmetric nuclear matter.Recent studies have suggested that the experimental data from the CREX and PREX2 collaborations are not mutually compatible with existing nuclear models.In this study,we review the quantification of the slope parameter of the symmetry energy L from the neutron skin thicknesses of^(48)Ca and^(208)Pb.Skyrme energy density functionals classified by various isoscalar incompressibility coefficients K were employed to evaluate the bulk properties of finite nuclei.The calculated results suggest that the slope parameter L deduced from^(208)Pb is sensitive to the compression modulus of symmetric nuclear matter,but not that from^(48)Ca.The effective parameter sets classified by K=220 MeV can provide an almost overlapping range of L from^(48)Ca and^(208)Pb.展开更多
The interfacial heat transfer coefficient between hot profile surface and cooling water was determined by using inverse heat conduction model combined with end quenching experiment. Then, a Deform-3 D thermo-mechanica...The interfacial heat transfer coefficient between hot profile surface and cooling water was determined by using inverse heat conduction model combined with end quenching experiment. Then, a Deform-3 D thermo-mechanical coupling model for simulating the on-line water quenching of extruded profile with unequal and large thicknesses was developed. The temperature field, residual stress field and distortion of profile during quenching were investigated systematically. The results show that heat transfer coefficient increases as water flow rate increases. The peak heat transfer coefficient with higher water flow rates appears at lower interface temperatures. The temperature distribution across the cross-section of profile during quenching is severe nonuniform and the maximum temperature difference is 300 ℃ at quenching time of 3.49 s. The temperature difference through the thickness of different parts of profile first increases sharply to a maximum value, and then gradually decreases. The temperature gradient increases obviously with the increase of thickness of parts. After quenching, there exist large residual stresses on the inner side of joints of profile and the two ends of part with thickness of 10 mm. The profile presents a twisting-type distortion across the cross-section under non-uniform cooling and the maximum twisting angle during quenching is 2.78°.展开更多
[Objective] The research aimed to explore the most suitable gravel cover- ing thickness for selenium sand melon in arid region of central Ningxia. [Method] The natural gravel, which was from Nanshantai Region in Zhong...[Objective] The research aimed to explore the most suitable gravel cover- ing thickness for selenium sand melon in arid region of central Ningxia. [Method] The natural gravel, which was from Nanshantai Region in Zhongwei City, Ningxia, was acted as test materials to study the effects of different thicknesses of gravel covering on daily evaporation using evaporator overall weighing method. [Result] The daily evaporation capacity order of the gravel covering thickness was as follows： CK〉HI（5 cm）〉 H2（8 cm）〉 H3（10 cm）〉 H4（15 cm）. Meanwhile, with the increase of test days, the difference of cumulative evaporation capacity between H3 （10 cm） and H4 （15 cm） decreased gradually. Soil evaporation capacity reduced at the pow- er function with the increase of gravel covering thickness, and the decision coeffi- cient of the fitted curve reached to 0.925 5. [Conclusion] With the increase of gravel covering thickness, evaporation capacity of soil reduced gradually, and the soil water content increased gradually. Gravel covering could effectively reduce the evapora- tion. The thicker of covering, the more obvious inhibition effect on evaporation. The thickness of covering should increase moderately to prevent moisture loss from e- vaporation. Gravel inhibition effect on the evaporation wasn＇t obvious when the gravel covering thickness reached more than 10 cm. 10 cm gravel covering was the most appropriate thickness for local natural condition. The soil evaporation capacity along with the change of gravel covering could be simulated with power function e- quation Y=at^b.展开更多
A simplified theoretical model for the linear Rayleigh-Taylor instability of finite thickness elastic-plastic solid constantly accelerated by finite thickness viscous fluid is performed.With the irrotational assumptio...A simplified theoretical model for the linear Rayleigh-Taylor instability of finite thickness elastic-plastic solid constantly accelerated by finite thickness viscous fluid is performed.With the irrotational assumption,it is possible to consider viscosity,surface tension,elasticity or plasticity effects simultaneously.The model considers thicknesses at rigid wall boundary conditions with the velocity potentials,and deals with solid elastic-plastic transition and fluid viscosity based on the velocity continuity and force equilibrium at contact interface.The complete analytical expressions of the amplitude motion equation,the growth rate,and the instability boundary are obtained for arbitrary Atwood number,viscosity,thicknesses of solid and fluid.The thicknesses effects of two materials on the growth rate and the instability boundary are discussed.展开更多
The effects of the thickness of MgO and Fe on the electronic structure and magnetic properties of Fe/MgO/Fe magnetic tunnel junction was studied using the first principle method. Two series of models with MgO of diffe...The effects of the thickness of MgO and Fe on the electronic structure and magnetic properties of Fe/MgO/Fe magnetic tunnel junction was studied using the first principle method. Two series of models with MgO of different thicknesses： Fe（3）MgO（t）Fe（3） （t-=1,3,5,7） and with Fe of varied thicknesses： Fe（t）MgO（3）Fe（t） （t=3,4,5,6,7） were established. Calculated results show that in all the models the magnetic moment of Fe increases at the Fe/MgO interface and surface as compared with that of the inner layers. The mag- netic moment of each Fe layer was found to be independent of MgO thicknesses, while the spin-polarization of Fe layer at the interface shows a slight change in function of the MgO thicknesses. The tunneling magnetoresistance （TMR） ratio estimated by the Julliere model has the same change tendency as the spin-polarization has, and the largest value is obtained at the MgO thickness of 5 atomic layers. When the Fe thickness increases, the spin-polarization of interface Fe layer follows up an increase with a decrease. The highest TMR value is achieved when the Fe thickness is of 4 atomic layers.展开更多
We investigate the influence of interface charge on electrical performance of NbAIO/A1GaN/GaN metal-oxide- semiconductor high electron mobility transistors （MOSHEMTs）. Through C-V measurements and simulations, we fi...We investigate the influence of interface charge on electrical performance of NbAIO/A1GaN/GaN metal-oxide- semiconductor high electron mobility transistors （MOSHEMTs）. Through C-V measurements and simulations, we find that the donor-type interface fixed charge density Qit of 2.2 × 10^13 cm^-2 exists at the NbA10/A1GaN interface, which induces the shift of the threshold voltage much more negative. Furthermore, a trap density of approximately 0.43 × 10^13-1.14 ×10^13 cm^-2 eV^-1 is obtained at the NaA10/AlGaN interface, which is consistent with the frequency-dependent capacitance and conductance measurement results.展开更多
In the Southeast Margin of the Tibetan Plateau, low-velocity sedimentary layers that would significantly affect the accuracy of the H-κ stacking of receiver functions are widely distributed.In this study, we use tele...In the Southeast Margin of the Tibetan Plateau, low-velocity sedimentary layers that would significantly affect the accuracy of the H-κ stacking of receiver functions are widely distributed.In this study, we use teleseismic waveform data of 475 events from 97 temporary broadband seismometers deployed by ChinArray Phase I to obtain crustal thicknesses and Poisson's ratios within the Chuxiong-Simao Basin and adjacent area, employing an improved method in which the receiver functions are processed through a resonance-removal filter, and the H-κ stacking is time-corrected.Results show that the crustal thickness ranges from 30 to 55 km in the study area, reaching its thickest value in the northwest and thinning toward southwest, southeast and northeast.The apparent variation of crustal thickness around the Red River Fault supports the view of southeastern escape of the Tibetan Plateau.Relatively thin crustal thickness in the zone between Chuxiong City and the Red River Fault indicates possible uplift of mantle in this area.The positive correlation between crustal thickness and Poisson's ratio is likely to be related to lower crust thickening.Comparison of results obtained from different methods shows that the improved method used in our study can effectively remove the reverberation effect of sedimentary layers.展开更多
Geomorphological and Quaternarygeological field- and laboratory data (Fig.1) are introduced and interpreted with regard to the maximum Ice Age (LGM) glaciation of the Central-and South Karakoram in the Braldu-, Basna-...Geomorphological and Quaternarygeological field- and laboratory data (Fig.1) are introduced and interpreted with regard to the maximum Ice Age (LGM) glaciation of the Central-and South Karakoram in the Braldu-, Basna-, Shigar-and Indus valley system as well as on the Deosai plateau between the Skardu Basin and the Astor valley (Fig.2). These data result from two research expeditions in the years 1997 and 2000. They show that between c. 60 and 20 Ka the Central Karakorum and its south slope were covered by a continuous c. 125,000 km2 sized ice stream network. This ice stream network flowed together to a joint parent glacier, the Indus glacier. The tongue end of the Indus glacier reached down to 850 ～ 800 m a.s.l. In its centre the surface of this Indus ice stream network reached a height of a good 6000 m. Its most important ice thicknesses amounted to c. 2400 ～ 2900 m.展开更多
The spring flood of 2009 in the Red River Valley was exacerbated with severe ice breakup and ice jamming. To assist ice jam mitigation by cutting and breaking up the river ice cover before the flood season and to supp...The spring flood of 2009 in the Red River Valley was exacerbated with severe ice breakup and ice jamming. To assist ice jam mitigation by cutting and breaking up the river ice cover before the flood season and to support the operation of the Red River Floodway, Manitoba Water Stewardship is striving to model the occurrence of ice breakup and simulate the behaviour of ice jamming along the river. An important parameter in ice breakup forecasting is the ice thickness. RADARSAT-2 standard satellite images were collected along the course of the Red River in Manitoba during the 2009-2010 winter to help determine ice thicknesses along the river. Standard images can have transmit-receive polarizations in the horizontal-horizontal (HH) or horizontal-vertical (HV) configurations. Ice thickness measurements were taken in the field during the same time frame when the satellite passed over the Red River Valley. Good correlations were obtained between the HH-backscatter readings and the surveyed ice thicknesses. HV-backscatter readings correlate better with fresh snow depth measurements. Additionally, using same sensor incident angle and flight geometry allows ice thickening rate behavior over the course of the winter to be determined.展开更多
In view of the anisotropy,heterogeneity and stress-sensitive permeability in low permeability reservoirs,an analytical well test model was established by introducing the concept of permeability modulus.This model cons...In view of the anisotropy,heterogeneity and stress-sensitive permeability in low permeability reservoirs,an analytical well test model was established by introducing the concept of permeability modulus.This model considered the permeability stress-sensitivity,wellbore storage effect,and the skin effect.The perturbation technique and Laplace transformation were used to solve the mathematical model analytically in Laplace space,and the bottom-hole pressure type curves were plotted and analyzed in real space by using the Stehfest numerical inversion.展开更多
By using p-bis（p - N, N-diphenyl-aminostyryl）benzene doped 2-tert-butyl-9, 10-bis-β-naphthyl）-anthracene as an emitting layer, we fabricate a high-efficiency and long-lifetime blue organic light emitting diode wit...By using p-bis（p - N, N-diphenyl-aminostyryl）benzene doped 2-tert-butyl-9, 10-bis-β-naphthyl）-anthracene as an emitting layer, we fabricate a high-efficiency and long-lifetime blue organic light emitting diode with a maximum external quantum efficiency of 6.19% and a stable lifetime at a high initial current density of 0.0375 A/cm2. We demonstrate that the change in the thicknesses of organic layers affects the operating voltage and luminous efficiency greater than the lifetime. The lifetime being independent of thickness is beneficial in achieving high-quality full-colour display devices and white lighting sources with multi-emitters.展开更多
Luquire et al. ' s impedance change model of a rectangular cross section probe coil above a structure with an arbitrary number of parallel layers was used to study the principle of measuring thicknesses of multi-l...Luquire et al. ' s impedance change model of a rectangular cross section probe coil above a structure with an arbitrary number of parallel layers was used to study the principle of measuring thicknesses of multi-layered structures in terms of eddy current testing voltage measurements. An experimental system for multi-layered thickness measurement was developed and several fitting models to formulate the relationships between detected impedance/voltage measurements and thickness are put forward using least square method. The determination of multi-layered thicknesses was investigated after inversing the voltage outputs of the detecting system. The best fitting and inversion models are presented.展开更多
ZnO（002） films with different thicknesses, grown on Al2O3 （006） substrates by metal-organic chemical vapor deposition（ MOCVD）, were etched by Ar ion beams. The samples were examined by D8 X-ray diffraction, scan...ZnO（002） films with different thicknesses, grown on Al2O3 （006） substrates by metal-organic chemical vapor deposition（ MOCVD）, were etched by Ar ion beams. The samples were examined by D8 X-ray diffraction, scanning electron microscopy（SEM）, and photoluminescence（PL） spectrometry. The structural properties vary with the increasing thickness of the films. When the film thickness is thin, the phi（Φ） scanning curves for ZnO（103） and sapphire（116） substrate show the existence of two kinds of orientation relationships between ZnO films and sapphire, which are ZnO（002）//Al2O3 （006）, ZnO（ 100）//Al2O3 （110） and ZnO（002）//Al2O3 （006）, ZnO（ 110）//Al2O3 （110）. When the thickness increases to 500 nm there is only one orientation relationship, which is ZnO（002）// Al2O3 （006）, ZnO [ 100]//Al2O3 [ 110]. Their photoluminescence（PL） spectra at room temperature show that the optical properties of ZnO films have been greatly improved when increasing the thickness of films is increased.展开更多
Ag/La0.5 Mg0.5 MnO3/p+-Si resistance switching device for nonvolatile memory application was fabricated by sol-gel method. The thickness effects of La0.5 Mg0.5 MnO3（LMMO） films on current-voltage（I-V） characterist...Ag/La0.5 Mg0.5 MnO3/p+-Si resistance switching device for nonvolatile memory application was fabricated by sol-gel method. The thickness effects of La0.5 Mg0.5 MnO3（LMMO） films on current-voltage（I-V） characteristics, resistance switching behaviour and endurance characteristics of Ag/LMMO/p+-Si device were investigated. The same crystallisation and phase structure were confirmed in the LMMO films with increased film thickness. The Ag/LMMO/p+-Si device exhibits the typical bipolar resistive switching behaviour. As the LMMO thickness and the stable repetition switching cycle numbers increase, VSet, and VReset of the device will increase, but the RHRS/RLRS will decrease. The Ag/LMMO/p+-Si device with 165 nm thick LMMO films exhibit the best performance, in which the RHRS/RLRS exceeds 104 for 1 000 switching cycles, and its degradation is invisible for more than 106 s.展开更多
Superconducting magnetic levitation performance, including levitation force and guidance force, is important for the application of high-temperature super- conducting maglev. Both of them are not only affected by diff...Superconducting magnetic levitation performance, including levitation force and guidance force, is important for the application of high-temperature super- conducting maglev. Both of them are not only affected by different arrays of superconductors and magnets, but also by the thickness of the iron shim between permanent magnets. In order to obtain the best levitation performance, the magnetic field distribution, levitation force, and guidance force of a new type of three magnetic hills of permanent magnet guideway with iron shim of different thicknesses （4, 6, and 8 mm） are discussed in this paper. Simulation analysis and experiment results show that the guideway with iron shim of 8 mm thickness possesses the strongest magnetic field and levitation performance when the suspension gap is larger than 10 mm. However, with the decreasing of suspension gap, the guideway with iron shim of 4 mm thickness possesses the best levitation performance. The phenomena can be attributed to the density distribution of flux and magnetization of iron shim.展开更多
The specific binding of receptor to ligand covalently attached to surface with different surface densities was studied using streptavidin-biotin model pair. Biotinylated substrates with different spacer thicknesses as...The specific binding of receptor to ligand covalently attached to surface with different surface densities was studied using streptavidin-biotin model pair. Biotinylated substrates with different spacer thicknesses as formed through a simple reaction between amine immobilized surfaces and N-hydroxysucciimide groups at the end of biotin modifi ed PEG in anhydrous organic solutions（＂grafting to＂ technique）. The amount of the specifi cally adsorbed protein was measured as a function of spacer thickness between hard surface and biotin moieties. It has been shown that the amount of specifically adsorbed streptavidin decreases with the increase spacer thickness and the protein adsorbs onto the functionalized surfaces in a single molecular manner. It provides an interesting model system for studying single molecular interactions.展开更多
基金supported by the National Natural Science Foundation of China(grant no.52231004 and 52072305).
文摘Mg alloy matrix composites reinforced with short carbon fibers(C_(sf)/Mg)are considered as potential candidates for integrated structural-functional electronic parts that satisfy the requirements of lightweight,excellent mechanical properties,and heat dissipation.However,the different characteristics of C_(sf)and Mg alloy make the interface a critical issue affecting the synergistic improvement of thermal and mechanical properties of the composites.Here,Cu coating with different thicknesses is introduced to modify the C_(sf)/Mg interface,so as to simultaneously enhance the thermal and mechanical performances,which can combine the advantages of coating modification and matrix alloying.Results reveal that thermal diffusivity(TD)of 3-C_(sf)-Cu/Mg composites is as high as 22.12 mm^(2)/s and an enhancement of 52.97%is achieved compared with C_(sf)/Mg composites,as well as 16.3%enhancement of ultimate compressive strength(UCS)in the longitudinal direction,8.84%improvement of UCS in the transverse direction,and 53.08%increasement of ultimate tensile strength(UTS).Such improvement can be ascribed to the formation of intermetallic compounds.The formation of intermetallic compounds can not only effectively alleviate the lattice distortion of the matrix and decrease interfacial thermal resistance,but also bear the loads.Our work is of great significance for designing C_(sf)/Mg composites with integrated structure and function.
基金supported by the National Natural Science Foundation of China(No.52074130)Engineering Research Center of Resource Utilization of Carbon-containing Waste with Carbon Neutrality,Ministry of Education,200237 Shanghai,PR China.
文摘To advance the understanding of the corrosion behavior of stainless steel bellows in marine atmospheric environments and enhance the precision of service life predictions,this study employs finite element simulations to investigate the pitting corrosion rates and pit morphologies of bellows peaks and troughs under varying electrolyte film thicknesses.The model incorporates localized electrochemical reactions,oxygen concentration,and homogeneous solution reactions.For improved computational accuracy,the fitted polarization curve data were directly applied as nonlinear boundary conditions on the electrode surface via interpolation functions.Simulation results reveal that the peak regions exhibit faster corrosion rates than the trough regions.With increasing electrolyte film thickness(from 10μm to 500μm),corrosion rates at both peaks and troughs decrease progressively,and after 120 hours of simulation,the maximum corrosion rate at the peaks declines from 0.720 mm/a to 0.130 mm/a,and at the troughs from 0.520 mm/a to 0.120 mm/a,with the disparity in corrosion rates diminishing over time.Furthermore,as corrosion progresses,pits propagate deeper into the substrate,exhibiting both vertical penetration and lateral expansion along the passive film interface,ultimately breaching the substrate.This research offers valuable insights into designing corrosion mitigation strategies for stainless steel bellows in marine environments.
文摘In this paper,a meshfree Jacobi point interpolation(MJPI)approach for the dynamic analysis of sandwich laminated conical and cylindrical shells with varying thickness is presented.The theoretical formulations for sandwich laminated shells with varying thickness are established using the modified variational principle within the framework of first-order shear deformation theory(FSDT).The displacement components of the sandwich shell are expanded using the MJPI shape function and Fourier series in the meridional and circumferential directions,respectively.The accuracy and reliability of the proposed MJPI shape function are validated against numerical results from published literature and the commercial simulation tool Abaqus.Finally,the effects of different parameters such as thickness gradient,thickness power index and boundary condition on the free vibration and dynamic response of the sandwich laminated shell are investigated.
基金supported by National Natural Science Foundation of China(No.11405025).
文摘The yield ratios of neutron-proton(R(n/p))and^(3)H-^(3)He(R(^(3)H∕^(3)He))with reduced rapidity from 0 to 0.5 were simulated at 50 MeV/u even-even ^(36−56)Ca+^(40)Ca,even-even ^(48−78)Ni+^(58)Ni,and ^(100−139)Sn(every third isotopes)+112 Sn for full reduced impact parameters using the isospin-dependent quantum molecular dynamics(IQMD)model.The neutron and proton density distributions and root-mean-square radii of the reaction systems were obtained using the Skyrme-Hartree-Fock model,which was used for the phase space initialization of the projectile and target in IQMD.We defined the unified neutron skin thickness asΔRnp=<r^(2)>^(1∕2) n−<r^(2)>^(1∕2)p,which was negative for neutron-deficient nuclei.The unifiedΔRnp values for nuclei with the same relative neutron excess from different isotopic chains were nearly equal,except for extreme neutron-rich isotopes,which is a type of scaling behavior.The yield ratios of the three isotopic chain-induced reactions,which depended on the reduced impact parameter and unified neutron skin thickness,were studied.The results showed that both R(n/p)and R(^(3)H∕^(3)He)decreased with a reduced impact parameter for extreme neutron-deficient isotopes;however,they increased with reduced impact parameters for extreme neutron-rich isotopes,and increased with theΔRnp of the projectiles for all reduced impact parameters.In addition,a scaling phenomenon was observed betweenΔR np and the yield ratios in peripheral colli-sions from different isotopic chain projectiles(except for extreme neutron-rich isotopes).Thus,R(n/p)and R(^(3)H∕^(3)He)from peripheral collisions were suggested as experimental probes for extracting the neutron or proton skin thicknesses of non-extreme neutron-rich nuclei from different isotopic chains.
基金supported partly by the National Key R&D Program of China(No.2023YFA1606401)the National Natural Science Foundation of China(Nos.12135004,11635003,11961141004,12047513)+1 种基金the support of the National Natural Science Foundation of China(Nos.12275025 and 11975096)the Fundamental Research Funds for the Central Universities(No.2020NTST06)。
文摘Precise knowledge of the nuclear symmetry energy can be tentatively calibrated using multimessenger constraints.The neutron skin thickness of a heavy nucleus is one of the most sensitive indicators for probing the isovector components of effective interactions in asymmetric nuclear matter.Recent studies have suggested that the experimental data from the CREX and PREX2 collaborations are not mutually compatible with existing nuclear models.In this study,we review the quantification of the slope parameter of the symmetry energy L from the neutron skin thicknesses of^(48)Ca and^(208)Pb.Skyrme energy density functionals classified by various isoscalar incompressibility coefficients K were employed to evaluate the bulk properties of finite nuclei.The calculated results suggest that the slope parameter L deduced from^(208)Pb is sensitive to the compression modulus of symmetric nuclear matter,but not that from^(48)Ca.The effective parameter sets classified by K=220 MeV can provide an almost overlapping range of L from^(48)Ca and^(208)Pb.
基金Project(51605234)supported by the National Natural Science Foundation of ChinaProjects(2019JJ50510,2019JJ70077)supported by the Natural Science Foundation of Hunan Province,ChinaProjects(18B285,18B552)supported by Scientific Research Fund of Hunan Provincial Education Department,China。
文摘The interfacial heat transfer coefficient between hot profile surface and cooling water was determined by using inverse heat conduction model combined with end quenching experiment. Then, a Deform-3 D thermo-mechanical coupling model for simulating the on-line water quenching of extruded profile with unequal and large thicknesses was developed. The temperature field, residual stress field and distortion of profile during quenching were investigated systematically. The results show that heat transfer coefficient increases as water flow rate increases. The peak heat transfer coefficient with higher water flow rates appears at lower interface temperatures. The temperature distribution across the cross-section of profile during quenching is severe nonuniform and the maximum temperature difference is 300 ℃ at quenching time of 3.49 s. The temperature difference through the thickness of different parts of profile first increases sharply to a maximum value, and then gradually decreases. The temperature gradient increases obviously with the increase of thickness of parts. After quenching, there exist large residual stresses on the inner side of joints of profile and the two ends of part with thickness of 10 mm. The profile presents a twisting-type distortion across the cross-section under non-uniform cooling and the maximum twisting angle during quenching is 2.78°.
基金Supported by Natural Science Research Foundation Item of Ningxia University,China(ZR1208)Science and Technology Research Item of Ningxia Colleges and Universities,China(NGY2014065)~~
文摘[Objective] The research aimed to explore the most suitable gravel cover- ing thickness for selenium sand melon in arid region of central Ningxia. [Method] The natural gravel, which was from Nanshantai Region in Zhongwei City, Ningxia, was acted as test materials to study the effects of different thicknesses of gravel covering on daily evaporation using evaporator overall weighing method. [Result] The daily evaporation capacity order of the gravel covering thickness was as follows： CK〉HI（5 cm）〉 H2（8 cm）〉 H3（10 cm）〉 H4（15 cm）. Meanwhile, with the increase of test days, the difference of cumulative evaporation capacity between H3 （10 cm） and H4 （15 cm） decreased gradually. Soil evaporation capacity reduced at the pow- er function with the increase of gravel covering thickness, and the decision coeffi- cient of the fitted curve reached to 0.925 5. [Conclusion] With the increase of gravel covering thickness, evaporation capacity of soil reduced gradually, and the soil water content increased gradually. Gravel covering could effectively reduce the evapora- tion. The thicker of covering, the more obvious inhibition effect on evaporation. The thickness of covering should increase moderately to prevent moisture loss from e- vaporation. Gravel inhibition effect on the evaporation wasn＇t obvious when the gravel covering thickness reached more than 10 cm. 10 cm gravel covering was the most appropriate thickness for local natural condition. The soil evaporation capacity along with the change of gravel covering could be simulated with power function e- quation Y=at^b.
基金Project supported by of the Science Challenge Project of China(Grant No.TZ2018001)。
文摘A simplified theoretical model for the linear Rayleigh-Taylor instability of finite thickness elastic-plastic solid constantly accelerated by finite thickness viscous fluid is performed.With the irrotational assumption,it is possible to consider viscosity,surface tension,elasticity or plasticity effects simultaneously.The model considers thicknesses at rigid wall boundary conditions with the velocity potentials,and deals with solid elastic-plastic transition and fluid viscosity based on the velocity continuity and force equilibrium at contact interface.The complete analytical expressions of the amplitude motion equation,the growth rate,and the instability boundary are obtained for arbitrary Atwood number,viscosity,thicknesses of solid and fluid.The thicknesses effects of two materials on the growth rate and the instability boundary are discussed.
基金National Natural Science Foundation of China (60371001)
文摘The effects of the thickness of MgO and Fe on the electronic structure and magnetic properties of Fe/MgO/Fe magnetic tunnel junction was studied using the first principle method. Two series of models with MgO of different thicknesses： Fe（3）MgO（t）Fe（3） （t-=1,3,5,7） and with Fe of varied thicknesses： Fe（t）MgO（3）Fe（t） （t=3,4,5,6,7） were established. Calculated results show that in all the models the magnetic moment of Fe increases at the Fe/MgO interface and surface as compared with that of the inner layers. The mag- netic moment of each Fe layer was found to be independent of MgO thicknesses, while the spin-polarization of Fe layer at the interface shows a slight change in function of the MgO thicknesses. The tunneling magnetoresistance （TMR） ratio estimated by the Julliere model has the same change tendency as the spin-polarization has, and the largest value is obtained at the MgO thickness of 5 atomic layers. When the Fe thickness increases, the spin-polarization of interface Fe layer follows up an increase with a decrease. The highest TMR value is achieved when the Fe thickness is of 4 atomic layers.
基金Supported by the Basic Science Research Fund for the Central Universities of China under Grant No JB141104
文摘We investigate the influence of interface charge on electrical performance of NbAIO/A1GaN/GaN metal-oxide- semiconductor high electron mobility transistors （MOSHEMTs）. Through C-V measurements and simulations, we find that the donor-type interface fixed charge density Qit of 2.2 × 10^13 cm^-2 exists at the NbA10/A1GaN interface, which induces the shift of the threshold voltage much more negative. Furthermore, a trap density of approximately 0.43 × 10^13-1.14 ×10^13 cm^-2 eV^-1 is obtained at the NaA10/AlGaN interface, which is consistent with the frequency-dependent capacitance and conductance measurement results.
基金supported by the National Natural Science Foundation of China (Project 41730212)the Basic Research Project of the Institute of Earthquake Forecasting, China Earthquake Administration (2017IES0102)
文摘In the Southeast Margin of the Tibetan Plateau, low-velocity sedimentary layers that would significantly affect the accuracy of the H-κ stacking of receiver functions are widely distributed.In this study, we use teleseismic waveform data of 475 events from 97 temporary broadband seismometers deployed by ChinArray Phase I to obtain crustal thicknesses and Poisson's ratios within the Chuxiong-Simao Basin and adjacent area, employing an improved method in which the receiver functions are processed through a resonance-removal filter, and the H-κ stacking is time-corrected.Results show that the crustal thickness ranges from 30 to 55 km in the study area, reaching its thickest value in the northwest and thinning toward southwest, southeast and northeast.The apparent variation of crustal thickness around the Red River Fault supports the view of southeastern escape of the Tibetan Plateau.Relatively thin crustal thickness in the zone between Chuxiong City and the Red River Fault indicates possible uplift of mantle in this area.The positive correlation between crustal thickness and Poisson's ratio is likely to be related to lower crust thickening.Comparison of results obtained from different methods shows that the improved method used in our study can effectively remove the reverberation effect of sedimentary layers.
文摘Geomorphological and Quaternarygeological field- and laboratory data (Fig.1) are introduced and interpreted with regard to the maximum Ice Age (LGM) glaciation of the Central-and South Karakoram in the Braldu-, Basna-, Shigar-and Indus valley system as well as on the Deosai plateau between the Skardu Basin and the Astor valley (Fig.2). These data result from two research expeditions in the years 1997 and 2000. They show that between c. 60 and 20 Ka the Central Karakorum and its south slope were covered by a continuous c. 125,000 km2 sized ice stream network. This ice stream network flowed together to a joint parent glacier, the Indus glacier. The tongue end of the Indus glacier reached down to 850 ～ 800 m a.s.l. In its centre the surface of this Indus ice stream network reached a height of a good 6000 m. Its most important ice thicknesses amounted to c. 2400 ～ 2900 m.
文摘The spring flood of 2009 in the Red River Valley was exacerbated with severe ice breakup and ice jamming. To assist ice jam mitigation by cutting and breaking up the river ice cover before the flood season and to support the operation of the Red River Floodway, Manitoba Water Stewardship is striving to model the occurrence of ice breakup and simulate the behaviour of ice jamming along the river. An important parameter in ice breakup forecasting is the ice thickness. RADARSAT-2 standard satellite images were collected along the course of the Red River in Manitoba during the 2009-2010 winter to help determine ice thicknesses along the river. Standard images can have transmit-receive polarizations in the horizontal-horizontal (HH) or horizontal-vertical (HV) configurations. Ice thickness measurements were taken in the field during the same time frame when the satellite passed over the Red River Valley. Good correlations were obtained between the HH-backscatter readings and the surveyed ice thicknesses. HV-backscatter readings correlate better with fresh snow depth measurements. Additionally, using same sensor incident angle and flight geometry allows ice thickening rate behavior over the course of the winter to be determined.
基金support from the National 973 Program (Grant No. 2006CB705808)PetroChina Young and Middle Aged People Innovation Fund (Grant No. 07E1016)+1 种基金PetroChina Science & Technology Innovation Fund (Grant No. 2008D-5006-02-09)Science & Technology Innovation Fund of Southwest Petroleum University (Grant No. 2007XJZ010)
文摘In view of the anisotropy,heterogeneity and stress-sensitive permeability in low permeability reservoirs,an analytical well test model was established by introducing the concept of permeability modulus.This model considered the permeability stress-sensitivity,wellbore storage effect,and the skin effect.The perturbation technique and Laplace transformation were used to solve the mathematical model analytically in Laplace space,and the bottom-hole pressure type curves were plotted and analyzed in real space by using the Stehfest numerical inversion.
基金Project supported by the Science Fund of Science and Technology Commission of Shanghai Municipality,China (GrantNo. 10dz1140502)the Innovation Key Project of Education Commission of Shanghai Municipality,China (Grant No. 12ZZ091)the National Natural Science Foundation of China (Grant Nos. 61006005 and 61136003)
文摘By using p-bis（p - N, N-diphenyl-aminostyryl）benzene doped 2-tert-butyl-9, 10-bis-β-naphthyl）-anthracene as an emitting layer, we fabricate a high-efficiency and long-lifetime blue organic light emitting diode with a maximum external quantum efficiency of 6.19% and a stable lifetime at a high initial current density of 0.0375 A/cm2. We demonstrate that the change in the thicknesses of organic layers affects the operating voltage and luminous efficiency greater than the lifetime. The lifetime being independent of thickness is beneficial in achieving high-quality full-colour display devices and white lighting sources with multi-emitters.
文摘Luquire et al. ' s impedance change model of a rectangular cross section probe coil above a structure with an arbitrary number of parallel layers was used to study the principle of measuring thicknesses of multi-layered structures in terms of eddy current testing voltage measurements. An experimental system for multi-layered thickness measurement was developed and several fitting models to formulate the relationships between detected impedance/voltage measurements and thickness are put forward using least square method. The determination of multi-layered thicknesses was investigated after inversing the voltage outputs of the detecting system. The best fitting and inversion models are presented.
基金Supported by the National Natural Science Foundation of China(Nos. 20071013 and 20301007).
文摘ZnO（002） films with different thicknesses, grown on Al2O3 （006） substrates by metal-organic chemical vapor deposition（ MOCVD）, were etched by Ar ion beams. The samples were examined by D8 X-ray diffraction, scanning electron microscopy（SEM）, and photoluminescence（PL） spectrometry. The structural properties vary with the increasing thickness of the films. When the film thickness is thin, the phi（Φ） scanning curves for ZnO（103） and sapphire（116） substrate show the existence of two kinds of orientation relationships between ZnO films and sapphire, which are ZnO（002）//Al2O3 （006）, ZnO（ 100）//Al2O3 （110） and ZnO（002）//Al2O3 （006）, ZnO（ 110）//Al2O3 （110）. When the thickness increases to 500 nm there is only one orientation relationship, which is ZnO（002）// Al2O3 （006）, ZnO [ 100]//Al2O3 [ 110]. Their photoluminescence（PL） spectra at room temperature show that the optical properties of ZnO films have been greatly improved when increasing the thickness of films is increased.
基金Funded by the National Natural Science Foundation of China(No.51262003)the Guangxi Natural Science Foundation(No.2015GXNSFAA139253)
文摘Ag/La0.5 Mg0.5 MnO3/p+-Si resistance switching device for nonvolatile memory application was fabricated by sol-gel method. The thickness effects of La0.5 Mg0.5 MnO3（LMMO） films on current-voltage（I-V） characteristics, resistance switching behaviour and endurance characteristics of Ag/LMMO/p+-Si device were investigated. The same crystallisation and phase structure were confirmed in the LMMO films with increased film thickness. The Ag/LMMO/p+-Si device exhibits the typical bipolar resistive switching behaviour. As the LMMO thickness and the stable repetition switching cycle numbers increase, VSet, and VReset of the device will increase, but the RHRS/RLRS will decrease. The Ag/LMMO/p+-Si device with 165 nm thick LMMO films exhibit the best performance, in which the RHRS/RLRS exceeds 104 for 1 000 switching cycles, and its degradation is invisible for more than 106 s.
基金supported by the National Magnetic Confinement Fusion Science Program (2011GB112001)the Program of International S&T Cooperation (S2013ZR0595)+2 种基金the National Natural Science Foundation of China (No. 51271155)the Fundamental Research Funds for the Central Universities (SWJTU11CX073, SWJTU11ZT16 and SWJTU11ZT31)the Science Foundation of Sichuan Province (2011JY0031 and 2011JY0130)
文摘Superconducting magnetic levitation performance, including levitation force and guidance force, is important for the application of high-temperature super- conducting maglev. Both of them are not only affected by different arrays of superconductors and magnets, but also by the thickness of the iron shim between permanent magnets. In order to obtain the best levitation performance, the magnetic field distribution, levitation force, and guidance force of a new type of three magnetic hills of permanent magnet guideway with iron shim of different thicknesses （4, 6, and 8 mm） are discussed in this paper. Simulation analysis and experiment results show that the guideway with iron shim of 8 mm thickness possesses the strongest magnetic field and levitation performance when the suspension gap is larger than 10 mm. However, with the decreasing of suspension gap, the guideway with iron shim of 4 mm thickness possesses the best levitation performance. The phenomena can be attributed to the density distribution of flux and magnetization of iron shim.
文摘The specific binding of receptor to ligand covalently attached to surface with different surface densities was studied using streptavidin-biotin model pair. Biotinylated substrates with different spacer thicknesses as formed through a simple reaction between amine immobilized surfaces and N-hydroxysucciimide groups at the end of biotin modifi ed PEG in anhydrous organic solutions（＂grafting to＂ technique）. The amount of the specifi cally adsorbed protein was measured as a function of spacer thickness between hard surface and biotin moieties. It has been shown that the amount of specifically adsorbed streptavidin decreases with the increase spacer thickness and the protein adsorbs onto the functionalized surfaces in a single molecular manner. It provides an interesting model system for studying single molecular interactions.
