Layered rock mass of significant strength changes for adjacent layers is frequently observed in underground excavation,and dynamic loading is a prevalent scenario generated during excavation.In order to improve the dr...Layered rock mass of significant strength changes for adjacent layers is frequently observed in underground excavation,and dynamic loading is a prevalent scenario generated during excavation.In order to improve the driving efficiency and reduce engineering accidents,dynamic compression characteristics of this kind of rock mass should be understood.The dynamic properties of a layered composite rock mass are investigated through a series of rock tests and numerical simulations.The rock mass is artificially made of various proportions of sand,cement and water to control the distinct strength variations at various composite layers separated by parallel bedding planes.All rock specimens are prefabricated in a specially designed mould and then cut into 50 mm in diameter and 50 mm in height for split Hopkinson pressure bar(SHPB)dynamic compression testing.The test results reveal that increasing strain rate causes the increases of peak strength,σ_p,and the corresponding failure strain,ε_p,while the dynamic elastic modulus,E_d,remains almost unchanged.Interestingly,under the same strain rates,Ed of the composite rock specimen is found to decline first and then increase as the dip angle of bedding plane increases.The obtained rock failure patterns due to various dip angles lead to failure modes that could be classified into four categories from our dynamic tests.Also,a series of counterpart numerical simulations has been undertaken,showing that dynamic responses are in good agreement with those obtained from the SHPB tests.The numerical analysis enables us to Iook into the dynamic characteristics of the composite rock mass subjected to a broader range of strain rates and dip angles than these being tested.展开更多
A hysteresis-less inverted perovskite solar cell(PSC)with power conversion efficiency(PCE)of 13.57%was successfully achieved based on the thermal-decomposed NiO_(x) hole contact layer,possessing better electron blocki...A hysteresis-less inverted perovskite solar cell(PSC)with power conversion efficiency(PCE)of 13.57%was successfully achieved based on the thermal-decomposed NiO_(x) hole contact layer,possessing better electron blocking and hole extraction properties for its suitable work function and high-conduction band edge position.Herein,the transparent and high-crystalline NiO_(x) film is prepared by thermal-decomposing of the solution-derived Ni(OH)_(2) film in our study,which is then employed as hole transport layer(HTL)of the organic–inorganic hybrid PSCs.Reasonably,the post-annealing treatment,especially for the annealing temperature,could greatly affect the Ni(OH)_(2) decomposition process and the quality of decomposed NiO_(x) nanoparticles.The vital NiO_(x) HTLs with discrepant morphology,crystallinity and transmission certainly lead to a wide range of device performance.As a result,an annealing process of 400℃/2 h significantly promotes the photovoltaic properties of the NiO_(x) layer and the further device performance.展开更多
Antimony selenide is a promising semiconductor with great application potential in the fields of optoelectronic devices.In this work,the vapor transport deposition(VTD)method is employed to prepare Sb_(2)Se_(3)films o...Antimony selenide is a promising semiconductor with great application potential in the fields of optoelectronic devices.In this work,the vapor transport deposition(VTD)method is employed to prepare Sb_(2)Se_(3)films on substrates.The influence of deposition temperature,distance between the Sb_(2)Se_(3)sources and substrate,and the deposition holding time on the film morphology is investigated in detail.The deposited Sb_(2)Se_(3)thin film is employed to fabricate photodetector with a structure of ITO/SnO_(2)/Sb_(2)Se_(3)/Au,where the spin-coated SnO_(2)film is used as the buffer layer.The device demonstrates relative high responsivity in the range of 300-1000 nm with a maximum value of 312mAW^(-1)at 750 nm.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51608174)the Programmes for Science and Technology Development of Henan Province,China(Grant No.192102310014)。
文摘Layered rock mass of significant strength changes for adjacent layers is frequently observed in underground excavation,and dynamic loading is a prevalent scenario generated during excavation.In order to improve the driving efficiency and reduce engineering accidents,dynamic compression characteristics of this kind of rock mass should be understood.The dynamic properties of a layered composite rock mass are investigated through a series of rock tests and numerical simulations.The rock mass is artificially made of various proportions of sand,cement and water to control the distinct strength variations at various composite layers separated by parallel bedding planes.All rock specimens are prefabricated in a specially designed mould and then cut into 50 mm in diameter and 50 mm in height for split Hopkinson pressure bar(SHPB)dynamic compression testing.The test results reveal that increasing strain rate causes the increases of peak strength,σ_p,and the corresponding failure strain,ε_p,while the dynamic elastic modulus,E_d,remains almost unchanged.Interestingly,under the same strain rates,Ed of the composite rock specimen is found to decline first and then increase as the dip angle of bedding plane increases.The obtained rock failure patterns due to various dip angles lead to failure modes that could be classified into four categories from our dynamic tests.Also,a series of counterpart numerical simulations has been undertaken,showing that dynamic responses are in good agreement with those obtained from the SHPB tests.The numerical analysis enables us to Iook into the dynamic characteristics of the composite rock mass subjected to a broader range of strain rates and dip angles than these being tested.
基金funded by the National Natural Science Foundation of China(51502239)China Postdoctoral Science Foundation(2017T100751)+1 种基金Natural Science Basic Research Plan in Shaanxi Province of China(2016JQ6058)Postdoctoral Science Foundation in Shaanxi Province of China and the 111 Project of China(B14040)。
文摘A hysteresis-less inverted perovskite solar cell(PSC)with power conversion efficiency(PCE)of 13.57%was successfully achieved based on the thermal-decomposed NiO_(x) hole contact layer,possessing better electron blocking and hole extraction properties for its suitable work function and high-conduction band edge position.Herein,the transparent and high-crystalline NiO_(x) film is prepared by thermal-decomposing of the solution-derived Ni(OH)_(2) film in our study,which is then employed as hole transport layer(HTL)of the organic–inorganic hybrid PSCs.Reasonably,the post-annealing treatment,especially for the annealing temperature,could greatly affect the Ni(OH)_(2) decomposition process and the quality of decomposed NiO_(x) nanoparticles.The vital NiO_(x) HTLs with discrepant morphology,crystallinity and transmission certainly lead to a wide range of device performance.As a result,an annealing process of 400℃/2 h significantly promotes the photovoltaic properties of the NiO_(x) layer and the further device performance.
基金This work was supported by the China Postdoctoral Science Foundation(Grant No.2019M653639)the Fundamental Research Funds for the Central Universities(xjj2018021)SEM work was conducted at the International Center for Dielectric Research.
文摘Antimony selenide is a promising semiconductor with great application potential in the fields of optoelectronic devices.In this work,the vapor transport deposition(VTD)method is employed to prepare Sb_(2)Se_(3)films on substrates.The influence of deposition temperature,distance between the Sb_(2)Se_(3)sources and substrate,and the deposition holding time on the film morphology is investigated in detail.The deposited Sb_(2)Se_(3)thin film is employed to fabricate photodetector with a structure of ITO/SnO_(2)/Sb_(2)Se_(3)/Au,where the spin-coated SnO_(2)film is used as the buffer layer.The device demonstrates relative high responsivity in the range of 300-1000 nm with a maximum value of 312mAW^(-1)at 750 nm.
