Nickel-rich layered oxides have drawn sustainable attentions for lithium ion batteries owing to their higher theoretical capacities and lower cost.However,nickel-rich layered oxides also have exposed several defects f...Nickel-rich layered oxides have drawn sustainable attentions for lithium ion batteries owing to their higher theoretical capacities and lower cost.However,nickel-rich layered oxides also have exposed several defects for commercial application,such as uncontrollable ordered layered structure,which leads to higher energy barrier for Li+diffusion.In addition,suffering from structural mutability,the bulk nickelrich cathode materials likely trigger overall volumetric variation and intergranular cracks,thus obstructing the lithium ion diffusion path and shortening the service life of the whole device.Herein,we report wellordered layered Li Ni0.8Co0.1Mn0.1O2 submicron spheroidal particles via an optimized co-precipitation and investigated as LIBs cathodes for high-performance lithium storage.The as-fabricated Li Ni0.8Co0.1Mn0.1O2 delivers high initial capacity of 228 mAh g–1,remarkable energy density of 866 Wh kg–1,rapid Li ion diffusion coefficient(10–9cm2s–1)and low voltage decay.The remarkable electrochemical performance should be ascribed to the well-ordered layered structure and uniform submicron spheroidal particles,which enhance the structural stability and ameliorate strain relaxation via reducing the parcel size and shortening Li-ion diffusion distance.This work anticipatorily provides an inspiration to better design particle morphology for structural stability and rate capability in electrochemistry energy storage devices.展开更多
The nanorod structure is an alternative scheme to develop high-efficiency deep ultraviolet light-emitting diodes(DUV LEDs). In this paper, we first report the electrically injected 274-nm AlGaN nanorod array DUV LEDs ...The nanorod structure is an alternative scheme to develop high-efficiency deep ultraviolet light-emitting diodes(DUV LEDs). In this paper, we first report the electrically injected 274-nm AlGaN nanorod array DUV LEDs fabricated by the nanosphere lithography and dry-etching technique. Nanorod DUV LED devices with good electrical properties are successfully realized. Compared to planar DUV LEDs, nanorod DUV LEDs present>2.5 times improvement in light output power and external quantum efficiency. The internal quantum efficiency of nanorod LEDs increases by 1.2 times due to the transformation of carriers from the exciton to the free electron–hole, possibly driven by the interface state effect of the nanorod sidewall surface. In addition, the nanorod array significantly facilitates photons escaping from the interior of LEDs along the vertical direction, contributing to improved light extraction efficiency. A three-dimensional finite-different time-domain simulation is performed to analyze further in detail the TE-and TM-polarized photon extraction mechanisms of the nanostructure. Our results demonstrate the nanorod structure is a good candidate for high-efficiency DUV emitters.展开更多
?The multiplication semigroup of strongly regular ring R in the light of semigroup is researched,hence some properties of strongly regular rings are obtained. The non-division strongly regular ring R is anilpotent sem...?The multiplication semigroup of strongly regular ring R in the light of semigroup is researched,hence some properties of strongly regular rings are obtained. The non-division strongly regular ring R is anilpotent semisimple ring without identity element. It is neither the Artin ring nor the Noether ring. The setidempotents of ring R is an infinite set without the maximum and minimal conditions,it is a unions of someorder sets and hai a non-well-ordered order set at least.展开更多
We introduced the fuzzy axioms of choice,fuzzy Zorn’s lemma and fuzzy well-ordering principle,which are the fuzzy versions of the axioms of choice,Zorn’s lemma and well-ordering principle,and discussed the relations...We introduced the fuzzy axioms of choice,fuzzy Zorn’s lemma and fuzzy well-ordering principle,which are the fuzzy versions of the axioms of choice,Zorn’s lemma and well-ordering principle,and discussed the relations among them.As an application of fuzzy Zorn’s lemma,we got the following results:(1)Every proper fuzzy ideal of a ring was contained in a maximal fuzzy ideal.(2)Every nonzero ring contained a fuzzy maximal ideal.(3)Introduced the notion of fuzzy nilpotent elements in a ring R,and proved that the intersection of all fuzzy prime ideals in a commutative ring R is the union of all fuzzy nilpotent elements in R.(4)Proposed the fuzzy version of Tychonoff Theorem and by use of fuzzy Zorn’s lemma,we proved the fuzzy Tychonoff Theorem.展开更多
In this paper,a characteristic-set-based criterion is given to verify whether a polynomial is vanishing over an algebraic variety.The algorithm is feasible in practice,and does not depend on the decomposition of the v...In this paper,a characteristic-set-based criterion is given to verify whether a polynomial is vanishing over an algebraic variety.The algorithm is feasible in practice,and does not depend on the decomposition of the variety.展开更多
<正> By developing the mechanical proving method, we determine the structure of LaSalle’sinvariant set for 7-dimensional Lotka-Volterra food chain systems, based on Ritt-Wu’s prin-ciple. We then further show t...<正> By developing the mechanical proving method, we determine the structure of LaSalle’sinvariant set for 7-dimensional Lotka-Volterra food chain systems, based on Ritt-Wu’s prin-ciple. We then further show that the locally asymptotical stable equilibrium point of Lotka-Volterra food chain systems for 7 dimension must be globally stable.展开更多
基金supported by the National Natural Science Foundation of China (21573083)1000 Young Talent (to Deli Wang)the Innovation Research Funds of HuaZhong University of Science and Technology (2017KFYXJJ164)。
文摘Nickel-rich layered oxides have drawn sustainable attentions for lithium ion batteries owing to their higher theoretical capacities and lower cost.However,nickel-rich layered oxides also have exposed several defects for commercial application,such as uncontrollable ordered layered structure,which leads to higher energy barrier for Li+diffusion.In addition,suffering from structural mutability,the bulk nickelrich cathode materials likely trigger overall volumetric variation and intergranular cracks,thus obstructing the lithium ion diffusion path and shortening the service life of the whole device.Herein,we report wellordered layered Li Ni0.8Co0.1Mn0.1O2 submicron spheroidal particles via an optimized co-precipitation and investigated as LIBs cathodes for high-performance lithium storage.The as-fabricated Li Ni0.8Co0.1Mn0.1O2 delivers high initial capacity of 228 mAh g–1,remarkable energy density of 866 Wh kg–1,rapid Li ion diffusion coefficient(10–9cm2s–1)and low voltage decay.The remarkable electrochemical performance should be ascribed to the well-ordered layered structure and uniform submicron spheroidal particles,which enhance the structural stability and ameliorate strain relaxation via reducing the parcel size and shortening Li-ion diffusion distance.This work anticipatorily provides an inspiration to better design particle morphology for structural stability and rate capability in electrochemistry energy storage devices.
基金National Key R&D Program of China(2016YFB0400800)National Natural Science Foundation of China(61875187,61527814,61674147,U1505253)+1 种基金Beijing Nova Program(Z181100006218007)Youth Innovation Promotion Association of the Chinese Academy of Sciences(2017157)
文摘The nanorod structure is an alternative scheme to develop high-efficiency deep ultraviolet light-emitting diodes(DUV LEDs). In this paper, we first report the electrically injected 274-nm AlGaN nanorod array DUV LEDs fabricated by the nanosphere lithography and dry-etching technique. Nanorod DUV LED devices with good electrical properties are successfully realized. Compared to planar DUV LEDs, nanorod DUV LEDs present>2.5 times improvement in light output power and external quantum efficiency. The internal quantum efficiency of nanorod LEDs increases by 1.2 times due to the transformation of carriers from the exciton to the free electron–hole, possibly driven by the interface state effect of the nanorod sidewall surface. In addition, the nanorod array significantly facilitates photons escaping from the interior of LEDs along the vertical direction, contributing to improved light extraction efficiency. A three-dimensional finite-different time-domain simulation is performed to analyze further in detail the TE-and TM-polarized photon extraction mechanisms of the nanostructure. Our results demonstrate the nanorod structure is a good candidate for high-efficiency DUV emitters.
文摘?The multiplication semigroup of strongly regular ring R in the light of semigroup is researched,hence some properties of strongly regular rings are obtained. The non-division strongly regular ring R is anilpotent semisimple ring without identity element. It is neither the Artin ring nor the Noether ring. The setidempotents of ring R is an infinite set without the maximum and minimal conditions,it is a unions of someorder sets and hai a non-well-ordered order set at least.
基金Supported by the National Natural Science Foundation of China(11971384)by the grant of Natural Science Basic Research Program of Shaanxi(Program No.2021JM-137)the Fundamental Research Funds for the Central Universities under grant QTZX2106,China 111 Project(B16037)and OPPO Research Fund.
文摘We introduced the fuzzy axioms of choice,fuzzy Zorn’s lemma and fuzzy well-ordering principle,which are the fuzzy versions of the axioms of choice,Zorn’s lemma and well-ordering principle,and discussed the relations among them.As an application of fuzzy Zorn’s lemma,we got the following results:(1)Every proper fuzzy ideal of a ring was contained in a maximal fuzzy ideal.(2)Every nonzero ring contained a fuzzy maximal ideal.(3)Introduced the notion of fuzzy nilpotent elements in a ring R,and proved that the intersection of all fuzzy prime ideals in a commutative ring R is the union of all fuzzy nilpotent elements in R.(4)Proposed the fuzzy version of Tychonoff Theorem and by use of fuzzy Zorn’s lemma,we proved the fuzzy Tychonoff Theorem.
基金Project supported by the National "Scaling" Plan
文摘In this paper,a characteristic-set-based criterion is given to verify whether a polynomial is vanishing over an algebraic variety.The algorithm is feasible in practice,and does not depend on the decomposition of the variety.
基金Project supported by the National Natural Science Foundation of China.
文摘<正> By developing the mechanical proving method, we determine the structure of LaSalle’sinvariant set for 7-dimensional Lotka-Volterra food chain systems, based on Ritt-Wu’s prin-ciple. We then further show that the locally asymptotical stable equilibrium point of Lotka-Volterra food chain systems for 7 dimension must be globally stable.
