Sapphire hemispherical domes are machined through milling and shaping using brazed diamond tools.A mathematical model describing roughness for this processing method is established,and the relationship between roughne...Sapphire hemispherical domes are machined through milling and shaping using brazed diamond tools.A mathematical model describing roughness for this processing method is established,and the relationship between roughness and its influencing factors is analyzed.Experiments on the hemispherical dome shaping process are conducted to validate the model,analyzing the variation in roughness under different tool and workpiece rotational speeds.The results are consistent with the predictions of the established roughness model,suggesting that the model can be used to guide subsequent process experiments.Milling and shaping efficiency using brazed diamond tools typically can reach 14 g/min.The machined sapphire surfaces exhibit relatively few microcracks and minimal damage,with almost all exclusively visible grooves resulting from brittle fracture removal.The surface roughness after machining is below 2.5μm.Milling sapphire domes with brazed diamond tools represents a novel shaping technique characterized by high efficiency and high quality.展开更多
Thermal metamaterial represents a groundbreaking approach to control heat conduction,and,as a crucial component,thermal invisibility is of utmost importance for heat management.Despite the flourishing development of t...Thermal metamaterial represents a groundbreaking approach to control heat conduction,and,as a crucial component,thermal invisibility is of utmost importance for heat management.Despite the flourishing development of thermal invisibility schemes,they still face two limitations in practical applications.First,objects are typically completely enclosed in traditional cloaks,making them difficult to use and unsuitable for objects with heat sources.Second,although some theoretical proposals have been put forth to change the thermal conductivity of materials to achieve dynamic invisibility,their designs are complex and rigid,making them unsuitable for large-scale use in real threedimensional(3D)spaces.Here,we propose a concept of a thermal dome to achieve 3D invisibility.Our scheme includes an open functional area,greatly enhancing its usability and applicability.It features a reconfigurable structure,constructed with simple isotropic natural materials,making it suitable for dynamic requirements.The performance of our reconfigurable thermal dome has been confirmed through simulations and experiments,consistent with the theory.The introduction of this concept can greatly advance the development of thermal invisibility technology from theory to engineering and provide inspiration for other physical domains,such as direct current electric fields and magnetic fields.展开更多
As a highly coupled aggregate of tectonism,magmatism,and metamorphism,a gneiss dome is usually taken as a vital window for understanding the crustal internal structure and the exchange of material and energy during or...As a highly coupled aggregate of tectonism,magmatism,and metamorphism,a gneiss dome is usually taken as a vital window for understanding the crustal internal structure and the exchange of material and energy during orogenic exhumation.The Qinghe gneiss dome located in the eastern Chinese Altai orogen,lies in Qinghe County,Xinjiang,records important information of late accretionary orogeny associated with continental uplift and crustal growth.According to the field investigation,the dome shows core-mantle-margin domains,in which the core is composed of migmatized granite and gneiss,the mantle consists of banded gneiss,schist,and leptynite,and the margin has rock assemblages of phyllite,schist,and meta-sandstone.From the margin to the core,the dome can be divided into chlorite-sericite,andalusite-staurolite,sillimanite-biotite,and sillimanite-garnet metamorphic zones,recording progressive metamorphism.Detailed structural analyses in the Qinghe gneiss dome indicate progressive deformation from the margin to the core.Internal and external detachment faults are clarified,with the former characterized by inflow and outward migration of crustal material and the latter marked by brittle-ductile deformation with a lineation indicating lateral slip of the upper wall when the dome uplifted.Based on these faults,upper,middle,lower structural layers are observed from the outer to inner domains of the dome.Considering the general geological background and new data,the Qinghe gneiss dome probably predominantly underwent early ductile shear deformation and late heat-flow diapirism in the early Permian,closely related to upwelling of asthenosphere mantle that resulted from slab break-off in the extensional tectonic setting.展开更多
1.Objective The Songpan-Ganze terrane is a key region for understanding the tectonic evolution of the Tibetan Plateau and the Yangtze Craton.The Songpan-Ganzi complex comprises a thick succession of deformed Ladinian-...1.Objective The Songpan-Ganze terrane is a key region for understanding the tectonic evolution of the Tibetan Plateau and the Yangtze Craton.The Songpan-Ganzi complex comprises a thick succession of deformed Ladinian-Norian turbidites(ca.230-203 Ma),covering about 200000 km^(2)of the eastern Tibet Plateau with a volume of approximately 2.0×10^(6)km^(3)(Fig.1a).Furthermore,this complex has over 100 Permian-Cenozoic felsic plutons.展开更多
With excellent seeing conditions,ultra-low infrared background noise,high frequency of space debris transits,and continuous polar night coverage,Dome A in Antarctica has become an ideal platform for ground-based astro...With excellent seeing conditions,ultra-low infrared background noise,high frequency of space debris transits,and continuous polar night coverage,Dome A in Antarctica has become an ideal platform for ground-based astronomy and space situational monitoring.As a crucial observatory site for international deep space,deep Earth,deep sea,and polar exploration,it is very important to evaluate the suitability of Dome A as an observatory site.However,owing to extreme environmental constraints,the evaluation of site conditions is mainly based on single-point measurements,making it challenging to comprehensively evaluate the effective site range and uniformity.This study integrated satellite remote sensing data to develop a cross-comparison framework for diverse indicators across Dome A,to evaluate its spatial uniformity.We find that the area surrounding the Dome A site,defined within a roughly 1°×1°latitude and longitude range,possesses excellent astronomical observation conditions.展开更多
The Jianglang Dome has integral tectonostratigraphic units and contains a suite of high-grade stratiform Cu deposits.However,the formation mechanism of this dome and genetic model of Cu mineralization remain a matter ...The Jianglang Dome has integral tectonostratigraphic units and contains a suite of high-grade stratiform Cu deposits.However,the formation mechanism of this dome and genetic model of Cu mineralization remain a matter of debate.The resolution of these problems hinges on the presence of magmatic intrusions in the core.Here,we report bulk geochemical and zircon U-Pb data of a newly discovered syenite intrusion as well as chalcopyrite Re-Os dating results.We aim to explore genesis of the Jianglang Dome,genetic model of the stratiform Cu deposits,and rare metal mineralization potential of the syenite intrusion.The dated syenite sample yields an emplacement age of 207.1±2.0 Ma,which matches post-collisional extension in the Songpan-Ganze Orogen.The syenite rocks have average high(Zr+Nb+Ce+Y)concentrations of 512 ppm,10000.Ga/Al ratios of 3.97,and crystallization temperatures of 827°C,together with low Mg#values of 1.73;they fi t the A-type granitoid defi nition and a crustal origin.Chalcopyrite separates yield a Re-Os isochron age of 207.1±5.3 Ma,which markedly postdates the formation age of their orehosting rocks(the Liwu Group,ca.553 Ma).Our new age determination,together with previous chalcopyrite Re–Os isochron age of ca.151.1 Ma and sulfi de sulfur isotope(δ^(34)S_(V-CDT)=8.7‰–5.6‰)and tourmaline boron isotope(δ^(11)B=−15.47‰to−5.91‰)data,confi rms multistage epigenetic Cu mineralization related to magmatic-hydrothermal fl uids.Compared with regional ca.209–207 Ma fertile granitoids,the studied syenite intrusion shows unevolved and barren affi nities and negligible rare metal mineralization potential.Combined with residual gravity low anomalies in the core of the Jianglang Dome,which suggest a large deepseated granitic batholith,we prefer thermal doming resulting from magma-induced uplift for the nature of this dome.展开更多
The present paper investigates the methods for estimating the maximum(positive)and the minimum(negative)peak wind force coefficients on domed free roofs based on the quasi-steady theory and the peak factor method,in w...The present paper investigates the methods for estimating the maximum(positive)and the minimum(negative)peak wind force coefficients on domed free roofs based on the quasi-steady theory and the peak factor method,in which the experimental results obtained from our previous studies(2019,2025)are used.Focus is on the distributions of the peak wind force coefficients along the centerline parallel to the wind direction considering that domed free roof is an axisymmetric body.Empirical formulas are provided to the distributions of mean wind force coefficient,RMS(root mean square)fluctuating wind force coefficient and peak factors as a function of the rise/span ratio of the roof and the turbulence intensity of the approach flow in the along-wind direction at the mean roof height.The proposed methods are validated by the experimental results for the peak wind force coefficients.The methods would provide useful information to structural engineers when estimating the design wind loads on cladding/components of domed free roofs.展开更多
基金supported by the Na-tional Natural Science Foundation of China(No.51675457)the Jiangsu Key Laboratory of Precision and Micro-man-ufacturing Technology.
文摘Sapphire hemispherical domes are machined through milling and shaping using brazed diamond tools.A mathematical model describing roughness for this processing method is established,and the relationship between roughness and its influencing factors is analyzed.Experiments on the hemispherical dome shaping process are conducted to validate the model,analyzing the variation in roughness under different tool and workpiece rotational speeds.The results are consistent with the predictions of the established roughness model,suggesting that the model can be used to guide subsequent process experiments.Milling and shaping efficiency using brazed diamond tools typically can reach 14 g/min.The machined sapphire surfaces exhibit relatively few microcracks and minimal damage,with almost all exclusively visible grooves resulting from brittle fracture removal.The surface roughness after machining is below 2.5μm.Milling sapphire domes with brazed diamond tools represents a novel shaping technique characterized by high efficiency and high quality.
基金supported by the National Natural Science Foundation of China to Jiping Huang(12035004 and 12320101004)the Innovation Program of the Shanghai Municipal Education Commission to Jiping Huang(2023ZKZD06)+2 种基金the National Natural Science Foundation of China to Ying Li(92163123 and 52250191)the Zhejiang Provincial Natural Science Foundation of China to Ying Li(LZ24A050002)the National Natural Science Foundation of China to Liujun Xu(12375040,12088101,and U2330401).
文摘Thermal metamaterial represents a groundbreaking approach to control heat conduction,and,as a crucial component,thermal invisibility is of utmost importance for heat management.Despite the flourishing development of thermal invisibility schemes,they still face two limitations in practical applications.First,objects are typically completely enclosed in traditional cloaks,making them difficult to use and unsuitable for objects with heat sources.Second,although some theoretical proposals have been put forth to change the thermal conductivity of materials to achieve dynamic invisibility,their designs are complex and rigid,making them unsuitable for large-scale use in real threedimensional(3D)spaces.Here,we propose a concept of a thermal dome to achieve 3D invisibility.Our scheme includes an open functional area,greatly enhancing its usability and applicability.It features a reconfigurable structure,constructed with simple isotropic natural materials,making it suitable for dynamic requirements.The performance of our reconfigurable thermal dome has been confirmed through simulations and experiments,consistent with the theory.The introduction of this concept can greatly advance the development of thermal invisibility technology from theory to engineering and provide inspiration for other physical domains,such as direct current electric fields and magnetic fields.
基金financially supported by the National Key Research and Development Program(Grant No.2021YFC2901802)the Shaanxi Province Natural Science Foundation(Grant No.2020JM-310)+2 种基金the Hong Kong RGC Co-funding Mechanism on Joint Laboratories with the Chinese Academy of Science(JLFS/P-702/24)the National Key R&D Program of China(Grant Nos.2018YFC0604000,2017YFC0601205)the National Natural Science Foundation of China(Grant Nos.41730213,42072264,41902229,41972237).
文摘As a highly coupled aggregate of tectonism,magmatism,and metamorphism,a gneiss dome is usually taken as a vital window for understanding the crustal internal structure and the exchange of material and energy during orogenic exhumation.The Qinghe gneiss dome located in the eastern Chinese Altai orogen,lies in Qinghe County,Xinjiang,records important information of late accretionary orogeny associated with continental uplift and crustal growth.According to the field investigation,the dome shows core-mantle-margin domains,in which the core is composed of migmatized granite and gneiss,the mantle consists of banded gneiss,schist,and leptynite,and the margin has rock assemblages of phyllite,schist,and meta-sandstone.From the margin to the core,the dome can be divided into chlorite-sericite,andalusite-staurolite,sillimanite-biotite,and sillimanite-garnet metamorphic zones,recording progressive metamorphism.Detailed structural analyses in the Qinghe gneiss dome indicate progressive deformation from the margin to the core.Internal and external detachment faults are clarified,with the former characterized by inflow and outward migration of crustal material and the latter marked by brittle-ductile deformation with a lineation indicating lateral slip of the upper wall when the dome uplifted.Based on these faults,upper,middle,lower structural layers are observed from the outer to inner domains of the dome.Considering the general geological background and new data,the Qinghe gneiss dome probably predominantly underwent early ductile shear deformation and late heat-flow diapirism in the early Permian,closely related to upwelling of asthenosphere mantle that resulted from slab break-off in the extensional tectonic setting.
基金supported by the Science and Technology Major Project of the Sichuan Institute of Geological Survey(SCIGS-CZDXM-2023003)the National Natural Science Foundation of China(41603034).
文摘1.Objective The Songpan-Ganze terrane is a key region for understanding the tectonic evolution of the Tibetan Plateau and the Yangtze Craton.The Songpan-Ganzi complex comprises a thick succession of deformed Ladinian-Norian turbidites(ca.230-203 Ma),covering about 200000 km^(2)of the eastern Tibet Plateau with a volume of approximately 2.0×10^(6)km^(3)(Fig.1a).Furthermore,this complex has over 100 Permian-Cenozoic felsic plutons.
基金supported by the Space Debris Research Project,China(KJSP2020010102)the National Key R&D Program of China(2022YFC2807300).
文摘With excellent seeing conditions,ultra-low infrared background noise,high frequency of space debris transits,and continuous polar night coverage,Dome A in Antarctica has become an ideal platform for ground-based astronomy and space situational monitoring.As a crucial observatory site for international deep space,deep Earth,deep sea,and polar exploration,it is very important to evaluate the suitability of Dome A as an observatory site.However,owing to extreme environmental constraints,the evaluation of site conditions is mainly based on single-point measurements,making it challenging to comprehensively evaluate the effective site range and uniformity.This study integrated satellite remote sensing data to develop a cross-comparison framework for diverse indicators across Dome A,to evaluate its spatial uniformity.We find that the area surrounding the Dome A site,defined within a roughly 1°×1°latitude and longitude range,possesses excellent astronomical observation conditions.
基金supported by the National Natural Science Foundation of China(Nos.41902068,42272106)Young Scholars Development Fund of Southwest Petroleum University(No.201499010083)China Geological Survey Project(Nos.DD20230338,DD20242494)。
文摘The Jianglang Dome has integral tectonostratigraphic units and contains a suite of high-grade stratiform Cu deposits.However,the formation mechanism of this dome and genetic model of Cu mineralization remain a matter of debate.The resolution of these problems hinges on the presence of magmatic intrusions in the core.Here,we report bulk geochemical and zircon U-Pb data of a newly discovered syenite intrusion as well as chalcopyrite Re-Os dating results.We aim to explore genesis of the Jianglang Dome,genetic model of the stratiform Cu deposits,and rare metal mineralization potential of the syenite intrusion.The dated syenite sample yields an emplacement age of 207.1±2.0 Ma,which matches post-collisional extension in the Songpan-Ganze Orogen.The syenite rocks have average high(Zr+Nb+Ce+Y)concentrations of 512 ppm,10000.Ga/Al ratios of 3.97,and crystallization temperatures of 827°C,together with low Mg#values of 1.73;they fi t the A-type granitoid defi nition and a crustal origin.Chalcopyrite separates yield a Re-Os isochron age of 207.1±5.3 Ma,which markedly postdates the formation age of their orehosting rocks(the Liwu Group,ca.553 Ma).Our new age determination,together with previous chalcopyrite Re–Os isochron age of ca.151.1 Ma and sulfi de sulfur isotope(δ^(34)S_(V-CDT)=8.7‰–5.6‰)and tourmaline boron isotope(δ^(11)B=−15.47‰to−5.91‰)data,confi rms multistage epigenetic Cu mineralization related to magmatic-hydrothermal fl uids.Compared with regional ca.209–207 Ma fertile granitoids,the studied syenite intrusion shows unevolved and barren affi nities and negligible rare metal mineralization potential.Combined with residual gravity low anomalies in the core of the Jianglang Dome,which suggest a large deepseated granitic batholith,we prefer thermal doming resulting from magma-induced uplift for the nature of this dome.
文摘The present paper investigates the methods for estimating the maximum(positive)and the minimum(negative)peak wind force coefficients on domed free roofs based on the quasi-steady theory and the peak factor method,in which the experimental results obtained from our previous studies(2019,2025)are used.Focus is on the distributions of the peak wind force coefficients along the centerline parallel to the wind direction considering that domed free roof is an axisymmetric body.Empirical formulas are provided to the distributions of mean wind force coefficient,RMS(root mean square)fluctuating wind force coefficient and peak factors as a function of the rise/span ratio of the roof and the turbulence intensity of the approach flow in the along-wind direction at the mean roof height.The proposed methods are validated by the experimental results for the peak wind force coefficients.The methods would provide useful information to structural engineers when estimating the design wind loads on cladding/components of domed free roofs.
