Near-infrared excited rare-earth(RE)-doped up-conversion(UC)-luminescent materials have attracted enormous attention because of their unique emission properties,such as narrow emission bands,long luminescence lifetime...Near-infrared excited rare-earth(RE)-doped up-conversion(UC)-luminescent materials have attracted enormous attention because of their unique emission properties,such as narrow emission bands,long luminescence lifetimes,and multiple colors.However,current development of RE-doped luminescent material is hindered by weak and narrowband absorption problems and low photon-conversion quantum efficiencies.In addition to conventional approaches to enhance fluorescence intensity,controlling emission directivity to improve detection efficiency has become a promising approach to obtain higher luminescence brightnesses.In this paper,a self-suspended RE-doped UC luminescent waveguide is designed to realize directional emissions.Benefitting from the special morphology of the crown-like NaYF4:Yb3+/Er3+microparticle,the points contact between the waveguide and substrate can be obtained to decrease energy loss.An attractive UC luminescent pattern accompanied by powerful and controllable directional emissions is observed,and the spatial emission angle and intensity distribution are explored and analyzed in detail by introducing Fourier imaging detection and simulation.This work provides a new method for achieving controllable directional fluorescence emissions and obtaining improved detection efficiency by narrowing emission directivity,which has potential applications in 3-dimensional displays and micro-optoelectronic devices,especially when fabricating self-fluorescence micron lasers.展开更多
In order to solve the problems of data sharing security and policy conflict in multicloud storage systems(MCSS), this work designs an attribute mapping mechanism that extends ciphertext policy attribute-based encrypti...In order to solve the problems of data sharing security and policy conflict in multicloud storage systems(MCSS), this work designs an attribute mapping mechanism that extends ciphertext policy attribute-based encryption(CP-ABE), and proposes a multi-authority CP-ABE access control model that satisfies the need for multicloud storage access control. The mapping mechanism mainly involves the tree structure of CP-ABE and provides support for the types of attribute values. The framework and workflow of the model are described in detail. The effectiveness of the model is verified by building a simple prototype system, and the performance of the prototype system is analyzed. The results suggest that the proposed model is of theoretical and practical significance for access control research in MCSS. The CP-ABE has better performance in terms of computation time overhead than other models.展开更多
A suite of 27 oils from the Qinjiatun–Qikeshu oilfields in the Lishu Fault Depression of the Songliao Basin was analyzed using whole oil gas chromatography.In combination with the relative distribution of C27, C28,an...A suite of 27 oils from the Qinjiatun–Qikeshu oilfields in the Lishu Fault Depression of the Songliao Basin was analyzed using whole oil gas chromatography.In combination with the relative distribution of C27, C28,and C29 regular steranes, detailed geochemical analyses of light hydrocarbons in oil samples revealed crude oils characterized by the dual input of lower aquatic organisms and higher terrestrial plants. Several light hydrocarbon indicators suggest that the liquid hydrocarbons have maturities equivalent to vitrinite reflectances of around0.78%–0.93%. This is consistent with the maturity determination of steranes C2920 S/(20 S ? 20 R) and C29 aab/(aaa ? abb). Crude oils derived from the two distinct oilfields likely both have source rocks deposited in a lacustrine environment based on light hydrocarbon parameters and on higher molecular weight hydrocarbon parameters. The results show that light hydrocarbon data in crude oils can provide important information for understanding the geochemical characteristics of the Qinjiatun–Qikeshu oils during geologic evolution.展开更多
基金the National Natural Science Foundation of China(Grant Nos.11574190 and 11504224)the National Science Foundation of Shaanxi Province(Grant Nos.2019JQ-142 and 2019JM-441)the Fundamental Research Funds for Central Universities(Grant Nos.GK201701008,201903013,and 2017TS013).
文摘Near-infrared excited rare-earth(RE)-doped up-conversion(UC)-luminescent materials have attracted enormous attention because of their unique emission properties,such as narrow emission bands,long luminescence lifetimes,and multiple colors.However,current development of RE-doped luminescent material is hindered by weak and narrowband absorption problems and low photon-conversion quantum efficiencies.In addition to conventional approaches to enhance fluorescence intensity,controlling emission directivity to improve detection efficiency has become a promising approach to obtain higher luminescence brightnesses.In this paper,a self-suspended RE-doped UC luminescent waveguide is designed to realize directional emissions.Benefitting from the special morphology of the crown-like NaYF4:Yb3+/Er3+microparticle,the points contact between the waveguide and substrate can be obtained to decrease energy loss.An attractive UC luminescent pattern accompanied by powerful and controllable directional emissions is observed,and the spatial emission angle and intensity distribution are explored and analyzed in detail by introducing Fourier imaging detection and simulation.This work provides a new method for achieving controllable directional fluorescence emissions and obtaining improved detection efficiency by narrowing emission directivity,which has potential applications in 3-dimensional displays and micro-optoelectronic devices,especially when fabricating self-fluorescence micron lasers.
基金supported in part by the Basic Public Welfare Research Program of Zhejiang Province under Grant LGF19F020006 LGF20G030001 GF20G030006the NSFC-Zhejiang Joint Fund for the Integration of Industrialization and Informatization under Grant U1509219。
文摘In order to solve the problems of data sharing security and policy conflict in multicloud storage systems(MCSS), this work designs an attribute mapping mechanism that extends ciphertext policy attribute-based encryption(CP-ABE), and proposes a multi-authority CP-ABE access control model that satisfies the need for multicloud storage access control. The mapping mechanism mainly involves the tree structure of CP-ABE and provides support for the types of attribute values. The framework and workflow of the model are described in detail. The effectiveness of the model is verified by building a simple prototype system, and the performance of the prototype system is analyzed. The results suggest that the proposed model is of theoretical and practical significance for access control research in MCSS. The CP-ABE has better performance in terms of computation time overhead than other models.
基金financially supported by the National Oil and Gas Major Project(Grant No.2016ZX05007001-002)
文摘A suite of 27 oils from the Qinjiatun–Qikeshu oilfields in the Lishu Fault Depression of the Songliao Basin was analyzed using whole oil gas chromatography.In combination with the relative distribution of C27, C28,and C29 regular steranes, detailed geochemical analyses of light hydrocarbons in oil samples revealed crude oils characterized by the dual input of lower aquatic organisms and higher terrestrial plants. Several light hydrocarbon indicators suggest that the liquid hydrocarbons have maturities equivalent to vitrinite reflectances of around0.78%–0.93%. This is consistent with the maturity determination of steranes C2920 S/(20 S ? 20 R) and C29 aab/(aaa ? abb). Crude oils derived from the two distinct oilfields likely both have source rocks deposited in a lacustrine environment based on light hydrocarbon parameters and on higher molecular weight hydrocarbon parameters. The results show that light hydrocarbon data in crude oils can provide important information for understanding the geochemical characteristics of the Qinjiatun–Qikeshu oils during geologic evolution.
