In this paper, for the first time, the modified strain gradient theory is used as a new size-dependent Kirchhoff micro-plate model to study the effect of interlayer van der Waals （vdW） force for the vibration analys...In this paper, for the first time, the modified strain gradient theory is used as a new size-dependent Kirchhoff micro-plate model to study the effect of interlayer van der Waals （vdW） force for the vibration analysis of multilayered graphene sheets （MLGSs）. The model contains three material length scale parameters, which may effectively capture the size effect. The model can also degenerate into the modified couple stress plate model or the classical plate model, if two or all of the material length scale parameters are taken to be zero. After obtaining the governing equations based on modified strain gradient theory via principle of minimum potential energy, as only infinitesimal vibration is considered, the net pressure due to the vdW interaction is assumed to be linearly proportional to the deflection between two layers. To solve the goveming equation subjected to the boundary conditions, the Fourier series is assumed for w = w（x, y）. To show the accuracy of the formulations, present results in specific cases are compared with available results in literature and a good agreement can be seen. The results indicate that the present model can predict prominent natural frequency with the reduction of structural size, especially when the plate thickness is on the same order of the material length scale parameter.展开更多
Toroidal torques,generated by the resonant magnetic perturbation(RMP)and acting on the plasma column,are numerically systematically investigated for an ITER baseline scenario.The neoclassical toroidal viscosity(NTV),i...Toroidal torques,generated by the resonant magnetic perturbation(RMP)and acting on the plasma column,are numerically systematically investigated for an ITER baseline scenario.The neoclassical toroidal viscosity(NTV),in particular the resonant portion,is found to provide the dominant contribution to the total toroidal torque under the slow plasma flow regime in ITER.While the electromagnetic torque always opposes the plasma flow,the toroidal torque associated with the Reynolds stress enhances the plasma flow independent of the flow direction.A peculiar double-peak structure for the net NTV torque is robustly computed for ITER,as the toroidal rotation frequency is scanned near the zero value.This structure is found to be ultimately due to a non-monotonic behavior of the wave-particle resonance integral(over the particle pitch angle)in the superbanana plateau NTV regime in ITER.These findings are qualitatively insensitive to variations of a range of factors including the wall resistivity,the plasma pedestal flow and the assumed frequency of the rotating RMP field.展开更多
The Linglong gold ore field is situated in the northwestern region of the Jiaodong gold province,China,with over 1000 tons of gold resources.Although the metallogenic mechanism and fluid sources of the Linglong gold d...The Linglong gold ore field is situated in the northwestern region of the Jiaodong gold province,China,with over 1000 tons of gold resources.Although the metallogenic mechanism and fluid sources of the Linglong gold deposit have been the subject of extensive discussion and analyzed by numerous scholars,a definitive conclusion remains elusive.The Jiuqu Au deposit is a significant metallogenic area in the eastern part of the Linglong gold ore field,characterized as a quartz vein-type gold deposit.Gold mineralization in the Jiuqu gold deposit is classified into four stages,primarily occurring within the Late Jurassic Linglong granite and Early Cretaceous Guojialing granodiorite.Pyrite,the primary gold-bearing mineral at the Jiuqu Gold Mine,has been present throughout the metallogenic period,is rich in a variety of trace elements and is closely related to the formation of gold ore.This study focused on evaluating pyrite from the essential metallogenic stages(Stages Ⅰ-Ⅲ)of the Jiuqu gold deposit using scanning electron microscopy(SEM),electron microprobe analysis(EMPA),laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry(LA-MC-ICP-MS) sulfur isotope analysis and detection.The work aimed to reconstruct the origin of metallogenic materials and the evolution of ore-forming fluids and to restrict the genesis of the deposit.Pyrite exhibits discernible alterations in both shape and crystal structure as it progresses through its ore-forming stages.The aforementioned stages can be delineated as follows:type 1 pyrite(PyⅠ),developed in the initial ore stage,is characterized by coarse-to-medium-grained euhedral pyrite in Stage Ⅰ;type 2 pyrite(PyⅡ),developed in the second ore stage,appears during the middle stage of mineralization and is characterized by subhedral or anhedral pyrite;type 3 pyrite(PyⅢ),developed in the third ore stage,primarily occurred in the late-middle stages of mineralization.It is fragmented and coexists with various metal sulfides,including chalcopyrite,sphalerite and galena.The in situ major and elemental compositions of pyrites at Jiuqu indicate that Au,in the form of visible gold,exists in pyrites with low Au and Ag contents throughout all stages.PyⅠ had lower Pb,Bi,Co and Ni contents than those of PyⅡ.PyⅢ displayed decreased Pb,Bi,Co and Ni levels compared with PyⅡ.The δ34S values of the PyⅠ,PyⅡ and PyⅢ pyrite stages ranged from 7.19% to 8.71%,6.24% to 7.68% and 7.66% to 8.07%,respectively.According to the structural and geochemical analysis of pyrite,the ore-forming fluid of the Jiuqu gold deposit was derived from a magmatic-hydrothermal formation created by enriched lithospheric mantle-derived magma,mixing S from Precambrian metamorphic rocks.Previous studies on the H-O isotopes of quartz in the region's ores have indicated the presence of primary magma water.Additionally,studies concerning the C-O isotopes of carbonate minerals in ores have suggested that C may have originated from the mantle.Fluid migration and water-rock interaction resulted in sulfide and gold precipitation.In the Late Meosozoic,lithospheric thinning of eastern North China Craton led to up welling of astheno spheric mantle and partial melting of lithospheric mantle in the Jiaodong area.Under tectonic changes,magmatic-hydro thermal fluid migrated upward along fault structures to form a gold province.展开更多
BACKGROUND:Research has revealed a relationship between atrial fi brillation(AF)and valvular heart disease;however,the causality remains largely unknown.This study explored whether a causal association between AF and ...BACKGROUND:Research has revealed a relationship between atrial fi brillation(AF)and valvular heart disease;however,the causality remains largely unknown.This study explored whether a causal association between AF and non-rheumatic aortic valve disease(AVD)and mitral valve disease(MVD)could be found.METHODS:A two-sample Mendelian randomization(TSMR)method was applied to determine the causal eff ect of AF on AVD,mitral regurgitation,and MVD.The inverse variance weighted(IVW)method was used as the primary analytical approach,and several complementary analyses were conducted.Outliers were detected using the Mendelian Randomization Pleiotropy RESidual Sum and Outlier(MR-PRESSO)and radial Mendelian randomization(MR)methods.RESULTS:Genetically predicted AF was found to be causally associated with the risk of MVD(odds ratio[OR]=1.001;95%confi dence interval[CI]:1.000-1.001;P=1.33×10-6)and mitral regurgitation(OR=1.001;95%CI:1.000-1.002;P=0.009).However,no signifi cant causal associations between AF and AVD were detected(OR=1.000;95%CI:0.999-1.000;P=0.804).Causal eff ects were still detected,even after adjusting for potential risk factors or removing the identifi ed outliers.Reverse MR analyses revealed no signifi cant causal eff ect of valvular heart disease on AF.CONCLUSION:Our findings demonstrate a positive causal association between AF,MVD,and mitral regurgitation,but not AVD.Further research and an aggressive AF management strategy should be explored as potential measures for preventing MVD.展开更多
Experimental validation of laser intensity is particularly important for the study of fundamental physics at extremely high intensities.However,reliable diagnosis of the focal spot and peak intensity faces huge challe...Experimental validation of laser intensity is particularly important for the study of fundamental physics at extremely high intensities.However,reliable diagnosis of the focal spot and peak intensity faces huge challenges.In this work,we demonstrate for the firs time that the coherent radiation farfiel patterns from laser–foil interactions can serve as an in situ,real-time,and easy-to-implement diagnostic for an ultraintense laser focus.The laser-driven electron sheets,curved by the spatially varying laser fiel and leaving the targets at nearly the speed of light,produce doughnut-shaped patterns depending on the shapes of the focal spot and the absolute laser intensities.Assisted by particle-in-cell simulations,we can achieve measurements of the intensity and the focal spot,and provide immediate feedback to optimize the focal spots for extremely high intensity.展开更多
文摘In this paper, for the first time, the modified strain gradient theory is used as a new size-dependent Kirchhoff micro-plate model to study the effect of interlayer van der Waals （vdW） force for the vibration analysis of multilayered graphene sheets （MLGSs）. The model contains three material length scale parameters, which may effectively capture the size effect. The model can also degenerate into the modified couple stress plate model or the classical plate model, if two or all of the material length scale parameters are taken to be zero. After obtaining the governing equations based on modified strain gradient theory via principle of minimum potential energy, as only infinitesimal vibration is considered, the net pressure due to the vdW interaction is assumed to be linearly proportional to the deflection between two layers. To solve the goveming equation subjected to the boundary conditions, the Fourier series is assumed for w = w（x, y）. To show the accuracy of the formulations, present results in specific cases are compared with available results in literature and a good agreement can be seen. The results indicate that the present model can predict prominent natural frequency with the reduction of structural size, especially when the plate thickness is on the same order of the material length scale parameter.
基金funded by National Natural Science Foundation of China(NSFC)(Nos.12075053,11505021 and 11975068)by National Key R&D Program of China(No.2022YFE 03060002)+1 种基金by Fundamental Research Funds for the Central Universities(No.2232024G-10)supported by the U.S.DoE Office of Science(No.DE-FG02–95ER54309)。
文摘Toroidal torques,generated by the resonant magnetic perturbation(RMP)and acting on the plasma column,are numerically systematically investigated for an ITER baseline scenario.The neoclassical toroidal viscosity(NTV),in particular the resonant portion,is found to provide the dominant contribution to the total toroidal torque under the slow plasma flow regime in ITER.While the electromagnetic torque always opposes the plasma flow,the toroidal torque associated with the Reynolds stress enhances the plasma flow independent of the flow direction.A peculiar double-peak structure for the net NTV torque is robustly computed for ITER,as the toroidal rotation frequency is scanned near the zero value.This structure is found to be ultimately due to a non-monotonic behavior of the wave-particle resonance integral(over the particle pitch angle)in the superbanana plateau NTV regime in ITER.These findings are qualitatively insensitive to variations of a range of factors including the wall resistivity,the plasma pedestal flow and the assumed frequency of the rotating RMP field.
基金supported by the National Natural Science Foundation of China(42273063)the Young Elite Scientists Sponsorship(YESS)Program of the China Association for Science and Technology(YESS20220661)+1 种基金Fundamental Research Funds for Central Universities(FRF-IDRY-23-004)the Natural Science Foundation of Shandong Province,China(ZR2022QD050).
文摘The Linglong gold ore field is situated in the northwestern region of the Jiaodong gold province,China,with over 1000 tons of gold resources.Although the metallogenic mechanism and fluid sources of the Linglong gold deposit have been the subject of extensive discussion and analyzed by numerous scholars,a definitive conclusion remains elusive.The Jiuqu Au deposit is a significant metallogenic area in the eastern part of the Linglong gold ore field,characterized as a quartz vein-type gold deposit.Gold mineralization in the Jiuqu gold deposit is classified into four stages,primarily occurring within the Late Jurassic Linglong granite and Early Cretaceous Guojialing granodiorite.Pyrite,the primary gold-bearing mineral at the Jiuqu Gold Mine,has been present throughout the metallogenic period,is rich in a variety of trace elements and is closely related to the formation of gold ore.This study focused on evaluating pyrite from the essential metallogenic stages(Stages Ⅰ-Ⅲ)of the Jiuqu gold deposit using scanning electron microscopy(SEM),electron microprobe analysis(EMPA),laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry(LA-MC-ICP-MS) sulfur isotope analysis and detection.The work aimed to reconstruct the origin of metallogenic materials and the evolution of ore-forming fluids and to restrict the genesis of the deposit.Pyrite exhibits discernible alterations in both shape and crystal structure as it progresses through its ore-forming stages.The aforementioned stages can be delineated as follows:type 1 pyrite(PyⅠ),developed in the initial ore stage,is characterized by coarse-to-medium-grained euhedral pyrite in Stage Ⅰ;type 2 pyrite(PyⅡ),developed in the second ore stage,appears during the middle stage of mineralization and is characterized by subhedral or anhedral pyrite;type 3 pyrite(PyⅢ),developed in the third ore stage,primarily occurred in the late-middle stages of mineralization.It is fragmented and coexists with various metal sulfides,including chalcopyrite,sphalerite and galena.The in situ major and elemental compositions of pyrites at Jiuqu indicate that Au,in the form of visible gold,exists in pyrites with low Au and Ag contents throughout all stages.PyⅠ had lower Pb,Bi,Co and Ni contents than those of PyⅡ.PyⅢ displayed decreased Pb,Bi,Co and Ni levels compared with PyⅡ.The δ34S values of the PyⅠ,PyⅡ and PyⅢ pyrite stages ranged from 7.19% to 8.71%,6.24% to 7.68% and 7.66% to 8.07%,respectively.According to the structural and geochemical analysis of pyrite,the ore-forming fluid of the Jiuqu gold deposit was derived from a magmatic-hydrothermal formation created by enriched lithospheric mantle-derived magma,mixing S from Precambrian metamorphic rocks.Previous studies on the H-O isotopes of quartz in the region's ores have indicated the presence of primary magma water.Additionally,studies concerning the C-O isotopes of carbonate minerals in ores have suggested that C may have originated from the mantle.Fluid migration and water-rock interaction resulted in sulfide and gold precipitation.In the Late Meosozoic,lithospheric thinning of eastern North China Craton led to up welling of astheno spheric mantle and partial melting of lithospheric mantle in the Jiaodong area.Under tectonic changes,magmatic-hydro thermal fluid migrated upward along fault structures to form a gold province.
基金supported by grants from the National Key Research and Development Program of China(2023YFC3606500)the Natural Science Foundation of Zhejiang Province(LR22H020001)the National Natural Science Foundation of China(82470428).
文摘BACKGROUND:Research has revealed a relationship between atrial fi brillation(AF)and valvular heart disease;however,the causality remains largely unknown.This study explored whether a causal association between AF and non-rheumatic aortic valve disease(AVD)and mitral valve disease(MVD)could be found.METHODS:A two-sample Mendelian randomization(TSMR)method was applied to determine the causal eff ect of AF on AVD,mitral regurgitation,and MVD.The inverse variance weighted(IVW)method was used as the primary analytical approach,and several complementary analyses were conducted.Outliers were detected using the Mendelian Randomization Pleiotropy RESidual Sum and Outlier(MR-PRESSO)and radial Mendelian randomization(MR)methods.RESULTS:Genetically predicted AF was found to be causally associated with the risk of MVD(odds ratio[OR]=1.001;95%confi dence interval[CI]:1.000-1.001;P=1.33×10-6)and mitral regurgitation(OR=1.001;95%CI:1.000-1.002;P=0.009).However,no signifi cant causal associations between AF and AVD were detected(OR=1.000;95%CI:0.999-1.000;P=0.804).Causal eff ects were still detected,even after adjusting for potential risk factors or removing the identifi ed outliers.Reverse MR analyses revealed no signifi cant causal eff ect of valvular heart disease on AF.CONCLUSION:Our findings demonstrate a positive causal association between AF,MVD,and mitral regurgitation,but not AVD.Further research and an aggressive AF management strategy should be explored as potential measures for preventing MVD.
基金supported by the Guangdong High Level Innovation Research Institute(Grant No.2021B0909050006)the National Grand Instrument Project(Grant No.2019YFF01014402)+1 种基金the National Natural Science Foundation of China(Grant No.12205008)support from the National Science Fund for Distinguished Young Scholars(Grant No.12225501)。
文摘Experimental validation of laser intensity is particularly important for the study of fundamental physics at extremely high intensities.However,reliable diagnosis of the focal spot and peak intensity faces huge challenges.In this work,we demonstrate for the firs time that the coherent radiation farfiel patterns from laser–foil interactions can serve as an in situ,real-time,and easy-to-implement diagnostic for an ultraintense laser focus.The laser-driven electron sheets,curved by the spatially varying laser fiel and leaving the targets at nearly the speed of light,produce doughnut-shaped patterns depending on the shapes of the focal spot and the absolute laser intensities.Assisted by particle-in-cell simulations,we can achieve measurements of the intensity and the focal spot,and provide immediate feedback to optimize the focal spots for extremely high intensity.
