Quantitative description of characteristics of high-capacity channels in unconsolidated sandstone reservoirs using in situ production data

Quantitative description of the high-capacity channels in unconsolidated sandstone reservoirs, into which water was injected to improve oil recovery, is a hot topic in the field of reservoir development. This paper presents a novel approach to describing quantitatively the characteristics of connected macropores in unconsolidated sandstone reservoirs using in situ production data. Based on physical simulation for formation mechanisms of high capacity channels and interwell tracer test data, a mathematical model was established to describe high-capacity channels by grey correlation theory, flow mechanism of fluid in porous media and reservoir engineering, and a program was developed to describe quantitatively the channel characteristics. The predicted results were consistent with field monitoring data （80%）, so this model could be economically and effectively used to identify high-capacity channels.

High-capacity three-party quantum secret sharing with superdense coding

This paper presents a scheme for high-capacity three-party quantum secret sharing with quantum superdense coding, following some ideas in the work by Liuet al （2002 Phys. Rev. A 65 022304） and the quantum secret sharing scheme by Deng et al （2008 Phys. Lett. A 372 1957）. Instead of using two sets of nonorthogonal states, the boss Alice needs only to prepare a sequence of Einstei^Podolsky-l^osen pairs in d-dimension. The two agents Bob and Charlie encode their information with dense coding unitary operations, and security is checked by inserting decoy photons. The scheme has a high capacity and intrinsic efficiency as each pair can carry 21bd bits of information, and almost all the pairs can be used for carrying useful information.

Stress release in high-capacity flexible lithium-ion batteries through nested wrinkle texturing of graphene

Flexible lithium-ion batteries(LIBs)are critical for the development of next-generation smart electronics.Conversion reaction-based electrodes have been considered promising to construct high energy-density flexible LIBs,which satisfy the ever-increasing demand for practical use.However,these electrodes suffer from inferior lithium-storage performance and structural instability during deformation and long-term lithiation/delithiation.These are caused by the sluggish reaction kinetics of active-materials and the superposition of responsive strains originating from the large lithiation-induced stress and applied stress.Here,we propose a stress-release strategy through elastic responses of nested wrinkle texturing of graphene,to achieve high deformability while maintaining structural integrity upon prolonged cycles within high-capacity electrodes.The wrinkles endow the electrode with a robust and flexible network for effective stress release.The resulting electrode shows large reversible stretchability,along with excellent electrochemical performance including high specific capacity,high-rate capability and long-term cycling stability.This strategy offers a new way to obtain high-performance flexible electrodes and can be extended to other energy-storage devices.

Atomic Layer Deposition of High-Capacity Anodes for Next-Generation Lithium-Ion Batteries and Beyond

Electrification has great impacts on our modern society.To electrify future transportation,state-of-the-art lithium-ion batteries(LIBs)are still not sufficient in multiple aspects including cost,energy density,lifespan,and safety.To this end,next-generation high-energy LIBs and beyond are highly regarded.In this regard,high-capacity anodes are undergoing intensive investigation,such as silicon,SnO_(2),and lithium metal.However,such anode materials are commonly experiencing large volume changes and related issues,which are reflected on mechanical degradation,capacity fading,low efficiency,and unsatisfactory lifetime.To address these challenges,many technical strategies have been investigated.In the past decade,atomic layer deposition(ALD)has emerged as a new promising technique enabling atomic-scale surface modification and nanoscale design of high-capacity anodes for high performance.In this review,recent ALD studies on developing high-capacity anodes for LIBs and beyond are thoroughly summarized.In addition,ALD strategies and their effectiveness in pursing high-energy LIBs and beyond are discussed.Particularly,we highlighted the latest advances of ALD for addressing the notorious issues associated with Li metal anodes.It is expected that this work will promote the applications of ALD in new battery systems.

High-Capacity Quantum Secure Communication with Authentication Using Einstein-Podolsky-Rosen Pairs

A new protocol for quantum secure communication with authentication is proposed. The proposed protocol has a higher capacity as each EPR pair can carry four classical bits by the XOR operation and an auxiliary photon. Tile security and efficiency are analyzed in detail and the major advantage of this protocol is that it is more efficient without losing security.

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Analytic calculation of magnetic force between two current-carrying coils

Current-carrying coils are basic elements in electromagnetic equipments, for example, in high field magnets from high temperature superconducting wires or tapes. In the assembly of these systems and their current-carrying operation, unavoidable mis- alignment and shift from the original position can be induced by disturbances such as the imbalance of magnetic force due to safety problems. For two current-carrying coils with non-coplanar axes, the analytic expression of the magnetic force between the two coils is presented according to the rule of Ampere circulation and the Biot-Savart law. Based on the expression, the dependence of the magnetic force on the size and the relative position of each other is further investigated, and the variation of the magnetic force is obtained with the above parameters.

Numerical Analysis on the Magneto-Elastic Stability of Current-Carrying Conductors: Aiming at Applications for the Tokamak System

A novel method for calculating the magnetic stiffness matrix was proposed for the numerical analysis of the magneto-elastic stability of complicated current-carrying structures aim- ing for application in the magneto-elastic behavior of the tokamak system. A code based on the proposed method was developed and applied to the numerical analysis of two typical current- carrying structures. The good consistency of the numerical and analytical results validated the proposed method and the related numerical code.

Vacuum current-carrying tribological behavior of MoS2-Ti films with different conductivities

Current-carrying sliding is widely applied in aerospace equipment,but it is limited by the poor lubricity of the present materials and the unclear tribological mechanism.This study demonstrated the potential of MoS_(2)-based materials with excellent lubricity as space sliding electrical contact materials by doping Ti to improve its conductivity.The tribological behavior of MoS_(2)-Ti films under current-carrying sliding in vacuum was studied by establishing a simulation evaluating device.Moreover,the noncurrent-carrying sliding and static current-carrying experiments in vacuum were carried out for comparison to understand the tribological mechanism.In addition to mechanical wear,the current-induced arc erosion and thermal effect take important roles in accelerating the wear.Arc erosion is caused by the accumulation of electric charge,which is related to the conductivity of the film.While the current-thermal effect softens the film,causing strong adhesive wear,and good conductivity and the large contact area are beneficial for minimizing the thermal effect.So the moderate hardness and good conductivity of MoS_(2)-Ti film contribute to its excellent current-carrying tribological behavior in vacuum,showing a significant advantage compared with the traditional ones.

Lorentz Force from a Current-Carrying Wire on a Charge in Motion under the Assumption of Neutrality in the Symmetrical Frame of Reference

It is commonly assumed that a wire conducting an electric current is neutral in the laboratory frame of reference (the rest frame of the lattice of positive ions). Some authors consider that the wire is neutral only in a symmetrical frame of reference, in which the velocities of electrons and protons have equal norm and opposite direction. In this paper, we discuss the Lorentz transformation between different frames of reference in the context of the special theory of relativity for a current-carrying conducting wire and a probe charge in motion with respect to the wire. A simple derivation of the Lorentz force in the laboratory frame of reference for the assumed neutrality in a symmetrical frame of reference is presented. We show that the Lorentz force calculated assuming neutrality in the symmetrical frame of reference and the one assuming neutrality in the laboratory frame of reference differ by a term corresponding to a change in the test charge speed of one half the drift velocity of the electrons.

γ-MnO2 nanorods/graphene composite as efficient cathode for advanced rechargeable aqueous zinc-ion battery

Aqueous Zn//MnO2 batteries are emerging as promising large-scale energy storage devices owing to their cost-effectiveness,high safety,high output voltage,and energy density.However,the MnO2 cathode suffers from intrinsically poor rate performance and rapid capacity deterioration.Here,we remove the roadblock by compositing MnO2 nanorods with highly conductive graphene,which remarkably enhances the electrochemical properties of the MnO2 cathode.Benefiting from the boosted electric conductivity and ion diffusion rate as well as the structural protection of graphene,the Zn//MnO2-graphene battery presents an admirable capacity of 301 mAh g^-1 at 0.5 A g^-1,corresponding to a high energy density of 411.6 Wh kg^-1.Even at a high current density of 10 A g^-1,a decent capacity of 95.8 mAh g^-1 is still obtained,manifesting its excellent rate property.Furthermore,an impressive power density of 15 kW kg^-1 is achieved by the Zn//MnO2-graphene battery.

Boosting redox activity on MXene-induced multifunctional collaborative interface in high Li2S loading cathode for high-energy Li-S and metallic Li-free rechargeable batteries

Use of metallic Li anode raises serious concerns on the safety and operational performance of Li-S batteries due to uncontrolled hazard of Li dendrite formation, which is difficultly eliminated as long as the metallic Li exists in the cells. Pairing lithium sulfide (Li2S) cathode with currently available metallic Lifree high-capacity anodes offers an alternative solution to this challenge. However, the performance of Li2S cathode is primarily restricted by high activation barrier upon initial charge, low active mass utilization and sluggish redox kinetics. Herein, a MXene-induced multifunctional collaborative interface is proposed to afford superb activity towards redox solid-liquid/liquid-liquid phase transformation, strong chemisorption, high conductivity and fast ionic/charge transport in high Li2S loading cathode. Applying collaborative interface effectively reduces initial voltage barrier of Li2S activation and regulates the kinetic behavior of redox polysulfide conversion. Therefore, stable operation of additive-free Li2S cathode with high areal capacities at high Li2S loading up to 9 mg cm^-2 can be achieved with less sacrifice of high capacity and rate capability in Li-S batteries. Rechargeable metallic Li-free batteries are successfully constructed by pairing this high-performance Li2S cathode with high-capacity metal oxide anodes, which delivers superior energy density to current Li-ion batteries.

Chip-Based High-Dimensional Optical Neural Network

Parallel multi-thread processing in advanced intelligent processors is the core to realize high-speed and high-capacity signal processing systems.Optical neural network(ONN)has the native advantages of high parallelization,large bandwidth,and low power consumption to meet the demand of big data.Here,we demonstrate the dual-layer ONN with Mach-Zehnder interferometer(MZI)network and nonlinear layer,while the nonlinear activation function is achieved by optical-electronic signal conversion.Two frequency components from the microcomb source carrying digit datasets are simultaneously imposed and intelligently recognized through the ONN.We successfully achieve the digit classification of different frequency components by demultiplexing the output signal and testing power distribution.Efficient parallelization feasibility with wavelength division multiplexing is demonstrated in our high-dimensional ONN.This work provides a high-performance architecture for future parallel high-capacity optical analog computing.

Al_2O_3 coated LiCoO_2 as cathode for high-capacity and long-cycling Li-ion batteries

Lithium-ion batteries(LIBs) as energy storage devices play an important role in all aspects of our life. The increasing energy demand of the society requires LIBs with higher energy density and better performance. We here develop a new and easy-to-scaleup sol-gel method to coat a surface protection layer on commercial LiCoO2cathode. We demonstrate that a proper thickness can improve the cycling life with a higher cut-off potential(4.5 V), larger energy capacity(180 mAh/g at 0.5 C) and better energy density(35% more compared to non-coated LiCoO2). The mechanism of the protection layer is also revealed by a combination of electron microscopy and synchrotron X-ray spectroscopy.

Graphdiyne Hybrid Nanowall Arrays for High-capacity Aqueous Rechargeable Zinc Ion Battery

Development of aqueous rechargeable zinc ion battery is an important direction towards grid energy storage sought in various applications.At present,the efficient utilization of aqueous rechargeable zinc ion batteries has been seriously affected due to the defects nature of the cathode materials,such as poor capacity,limited rate performance,and limited cycle stability.Therefore,the search for high-performance cathode materials is a main challenge in this field.Herein,we in-situ prepared graphdiyne-wrapped K_(0.25)·MnO_(2)(K_(0.25)·MnO_(2)@GDY)hybrid nanowall arrays as the cathode of aqueous rechargeable zinc ion battery.The hybridnanowall arrays have obviously alleviated the pulverization and sluggish kinetic process of MnO_(2) cathode materials and shown high specific capacity(520 mA·h/g at a current density of 55 mA/g),which is near-full two-electron capacity.The high specific capacity was resulted from more than one Zn^(2+)(de)intercalation process occurring per formula unit,in which we observed a structural evolution that partially stemmed from ion exchange between the intercalated K^(+) and Zn^(2+) ions during the discharge process.The present investigation not only provides a new material for the aqueous rechargeable Zn ion batteries,also contributes a novel route for the development of next generation aqueous rechargeable Zn ion batteries with high capacity.

Sodium-based dual-ion batteries via coupling high-capacity selenium/graphene anode with high-voltage graphite cathode

Dual ion batteries(DIBs) exhibit broad application prospects in the field of electrical energy storage(EES)devices with excellent properties,such as high voltage,high energy density,and low cost.In the graphitebased DIBs,high voltage is needed to store enough anions with the formation of anion intercalation compound XCn(X=AlCl4-,PF6-,TFSI-,etc.).Hence,it is difficult for graphite-based DIBs to match proper anodes and electrolytes.Here,an Se/graphene composite is prepared via a convenient method,and assembled into a dual-ion full battery(DIFB) as anode with graphite cathode and 1 mol/L NaPF6 in EC:EMC(1:1,v:v).This DIFB has achieved a high discharge capacity of 75.9 mAh/g and high medium output voltage of 3.5 V at 0.1 A/g.Actually,the suitable anode materials,such as the present Se/graphene composite,are extremely important for the development and application of graphite-based DIBs.This study is enlightening for the design of future low-cost EES devices including graphite-based DIBs.

Intrinsic electrochemical activity of Ni in Ni_(3)Sn_(4) anode accommodating high capacity and mechanical stability for fast-charging lithium-ion batteries

Fast interfacial kinetics derived from bicontinuous three-dimensional(3D)architecture is a strategic feature for achieving fast-charging lithium-ion batteries(LIBs).One of the main reasons is its large active surface and short diffusion path.Yet,understanding of unusual electrochemical properties still remain great challenge due to its complexity.In this study,we proposed a nickel–tin compound(Ni_(3)Sn_(4))supported by 3D Nickel scaffolds as main frame because the Ni_(3)Sn_(4) clearly offers a higher reversible capacity and stable cycling performance than bare tin(Sn).In order to verify the role of Ni,atomic-scale simulation based on density functional theory systematically addressed to the reaction mechanism and structural evolution of Ni_(3)Sn_(4) during the lithiation process.Our findings are that Ni enables Ni_(3)Sn_(4) to possess higher mechanical stability in terms of reactive flow stress,subsequently lead to improve Li storage capability.This study elucidates an understanding of the lithiation mechanism of Ni_(3)Sn_(4) and provides a new perspective for the design of high-capacity and high-power 3D anodes for fast-charging LIBs.

霓虹灯电子变压器实现双保护及多功能显示原理

霓虹灯电子变压器实现双保护及多功能显示原理刘凌云（平顶山教育学院）霓虹灯作为一种冷光源，它是物理学中辉光放电理论的具本实践．市场经济条件下，正向着“密、亮、跳”的电脑程控化方向发展．而通常的霓虹灯的闪烁一般要加一台控制器，且当灯管断裂或短路时，变压器...

Current-carrying friction in carbon coated ball bearing

In this work,we proposed a method for coating the whole surfaces of bearing balls uniformly by carbon film with a rotatable ball clamp.We studied the carbon/carbon friction with a self-designed currentcarrying ball bearing friction test system.A notable and instant friction force drop of 28%and significant carbon film wear alleviation were found when currents were applied.By using TEM-,SEM-,and EDS-analysis,special carbon stacks with a mixture of large wear particles and oxide were found in the wear areas under current applied condition.We elucidated the current-carrying friction mechanisms as follows:(1)wear particles formation;(2)wear particles charged by tribomicroplasma;(3)formation of surface passivated carbon stacks under electric force;(4)sliding between passivated carbon surfaces.This work may facilitate the development of novel solid-lubricated ball bearings and lay some foundations for current-carrying rolling friction.

Magnetron sputtering NbSe_(2)film as lubricant for space current-carrying sliding contact

This study demonstrates that magnetron-sputtered NbSe_(2)film can be used as a lubricant for space current-carrying sliding contact,which accommodates both metal-like conductivity and MoS_(2)-like lubricity.Deposition at low pressure and low energy is performed to avoid the generation of the interference phase of NbSe_(3).The composition,microstructure,and properties of the NbSe_(2)films are further tailored by controlling the sputtering current.At an appropriate current,the film changed from amorphous to crystalline,maintained a dense structure,and exhibited excellent comprehensive properties.Compared to the currently available electrical contact lubricating materials,the NbSe_(2)film exhibits a significant advantage under the combined vacuum and current-carrying conditions.The friction coefficient decreases from 0.25 to 0.02,the wear life increases more than seven times,and the electric noise reduces approximately 50%.