Energy Coupling Effect Research Articles

Decomposition analysis of renewable energy demand and coupling effect between renewable energy and energy demand: evidence from China

Driving up demand for renewable energy is key to China's response to the energy crisis and to controlling carbon emissions. Several studies have been conducted to explore the factors affecting renewable energy demand. However, the literature on the importance of technological innovation in fossil energy production in affecting renewable energy demand is scant. Therefore, it is essential to explore the impact of technological innovations in fossil energy production on renewable energy demand, as well as to reveal the dynamic penetration mechanism of renewable energy in the field of energy demand, to provide policy guidelines for China to promote its energy revolution. This study decomposes renewable energy demand into 10 drivers with the extended IDA-PDA (Index Decomposition Analysis and Production-theory Decomposition Analysis) model. Then the dynamic penetration mechanism of renewable energy on the energy demand side is revealed by combining the coupled model and the decomposition results. The results show that the investment intensity effects and energy restructuring contributed the most to renewable energy demand growth, contributing 60.73% and 79.97% respectively. Conversely, technological advances in fossil energy combustion made the largest negative cumulative contribution to renewable energy demand growth, with a cumulative negative contribution of -39.57%. The drivers of renewable energy demand vary considerably across types, regions and resource endowment levels, which means that regions should develop differentiated development strategies based on their own characteristics. In addition, the coupling effect between renewable energy demand and total energy demand is weakening, with market and policy effects becoming the drivers for augmenting the response of renewable energy to total energy demand. The findings of this study provide clear pathways for expanding renewable energy demand, offering important insights for the government to balance between promoting capital-driven interests and policy-driven development.

Confined Element Distribution with Structure-Driven Energy Coupling for Enhanced Prussian Blue Analogue Cathode.

The structural failure of Na2Mn[Fe(CN)6] could not be alleviated with traditional modification strategies through the adjustable composition property of Prussian blue analogues (PBAs), considering that the accumulation and release of stress derived from the MnN6 octahedrons are unilaterally restrained. Herein, a novel application of adjustable composition property, through constructing a coordination competition relationship between chelators and [Fe(CN)6]4- to directionally tune the enrichment of elements, is proposed to restrain structural degradation and induce unconventional energy coupling phenomenon. The non-uniform distribution of elements at the M1 site of PBAs (NFM-PB) is manipulated by the sequentially precipitated Ni, Fe, and Mn according to the Irving-William order. Electrochemically active Fe is operated to accompany Mn, and zero-strain Ni is modulated to enrich at the surface, synergistically mitigating with the enrichment and release of stress and then significantly improving the structural stability. Furthermore, unconventional energy coupling effect, a fusion of the electrochemical behavior between FeLS and MnHS, is triggered by the confined element distribution, leading to the enhanced electrochemical stability and anti-polarization ability. Consequently, the NFM-PB demonstrates superior rate performance and cycling stability. These findings further exploit potentialities of the adjustable composition property and provide new insights into the component design engineering for advanced PBAs.

Quantitative characterization of granite failure intensity under dynamic disturbance from energy standpoint

Abstract Quantitative evaluation of rock dynamic disaster intensity is a challenging and difficult task in the field of earth science. In this article, the dynamic compression tests of granite under different impact velocities are carried out, and the energy evolution characteristics of the dynamic failure process of granite are analyzed. The dynamic fracture characteristics of granite were studied by using computed tomography and section scanning equipment. The results show that the energy dissipation and energy accumulation mechanism of granite under dynamic loading are fundamentally changed with the increase of impact disturbance strength, which leads to the transformation of the failure mode from the tension-type sheet crack under low-speed impact to the complex network crack coupled by tension and shear under high-speed impact. At the same time, the greater the impact velocity, the larger the macroscopic crack density, the more uneven the particle distribution on the fracture section, the greater the roughness, and the higher the rock mass fracture degree. In accordance with the results, the energy distribution ratio is proposed to quantitatively characterize the coupling effect of energy dissipation and energy accumulation in the dynamic failure process of granite and to reflect its dynamic failure intensity. The higher the energy distribution ratio, the stronger the energy coupling effect and the more intense the dynamic failure of the rock mass.

Optical properties of inverted type-I InP quantum dots with near-infrared emission

Unlike conventional type-I InP-based quantum dots (QDs), inverted type-I QDs can push the emission wavelength to the near-infrared (NIR) range. However, the fundamental optical properties of such kinds of QDs have yet to be studied in depth. In this work, we report the optical properties of inverted type-I ZnSe/InP/ZnS QDs with photoluminescence (PL) emission in the first biological window. Using femtosecond ultrafast transient absorption, the electron-injection time, Auger lifetime, and hot-carrier cooling time of the inverted type-I QDs are determined. Their temperature-dependent PL spectrum reveals that these QDs possess a higher exciton-binding energy and weaker carrier-phonon coupling effect than conventional type-I InP-based QDs. Interestingly, the QDs have strong two-photon absorption cross sections in the second biological window, up to 5120 GM at 1200 nm. These results suggest that ZnSe/InP/ZnS QDs have potential applications for light emitting devices and deep-tissue bioimaging.

Plasmon-mediated exciton-phonon coupling in CdS microbelts

Investigating underlying coupling mechanism between surface plasmons (SPs) and excitons is playing a very important role to achieve higher efficient and more stable excitonic optoelectronic devices. Here, cadmium sulfide (CdS) microbelts sputtered with Au nanoparticles (NPs) have been prepared for exploring the SP-mediated energy coupling effect. The enhancement of excitonic emission intensity and a red-shift of the peaks have been surveyed in the Fabry-Perot (F-P) resonant lasing spectra. The investigation on temperature-dependent photoluminescence (TDPL) spectra from these samples demonstrate that the optical phenomenon can be attributed to the exciton–phonon coupling. The research results will provide a paramount importance of theoretical support for building effective and bright photoelectric devices based on the complex SP materials system.

High-temperature compressive performance of the pre-impacted 2D-C/SiC composites: Coupling effect of pre-impact energy, temperature, temperature-keeping duration, and strain rate

Two-dimensional carbon fiber reinforced silicon carbide (2D-C/SiC) composites are well-known for the high-temperature performance in aeronautical and aerospace fields, but they are susceptible to foreign object damage in service. Therefore, the high-temperature performance of pre-impacted 2D-C/SiC is closely connected with flight security. In this study, the pre-impact testing was conducted using a stress-reversal split Hopkinson bar, and the pre-impact energies were set from 0.1J to 0.9J. Subsequently, the pre-impacted specimens were heated for a period in the temperature-keeping procedure from 20 °C to 1600 °C. Oxidation kinetics of the pre-impacted 2D-C/SiC specimens were obtained based on the weight loss-temperature trends. Finally, the specimens were compressed under high temperatures at the strain rates from 10−4/s to 1000/s, so the residual compressive strength (RCS)-temperature trends were achieved. Hence, the correlation between the weight loss and the RCS was established. Interestingly, the pre-impact strengthening effect on the compressive strength was found. The results revealed that the RCS of 2D-C/SiC is affected by various parameters, providing new sights into the high-temperature damage tolerance of ceramic matrix composites.

A novel Quasi Opposition based controller design for hybrid AGC considering renewable energy and excitation cross coupling effect

ABSTRACT The paper addresses the Automatic Generation Control (AGC) of the interconnected two-area power system under deregulated environment. Area 1 includes thermal system, Distributed Generation (DG), and aggregate Electric Vehicle (EV) wheras area 2 contains thermal system, gas system, and aggregate electric vehicle. Nonlinearities such as Generation Rate Constraint (GRC), Governor Dead Band (GDB), Boiler Dynamics (BD), and Communication Delay (CD) are explored in the proposed test system to achieve a realistic approach. For considering cross coupling effect between excitation system and AGC, an exact model has been investigated. A novel cascade controller has been proposed to achieve the desired goal. For optimum values of controller, new novel Quasi Opposition Lion Optimization Algorithm (QOLOA) has been suggested and implemented for the studied system. The sensitivity analysis study was performed to assess the robustness of the proposed controller by varying system parameters. System parameters are varied by ±25%, ±35%, and ±50%, and the result shows the robustness of the controller and algorithm For the proposed controller, Figure of Demerit (FOD) is compared with various algorithms, and the Integral square Error (ISE) is taken as objective function. The optimistic results shows the effectiveness & superiority of proposed AGC in different scenario of deregulation.

Snap-buckling of functionally graded multilayer graphene platelet-reinforced composite curved nanobeams with geometrical imperfections

We in this paper dedicate to study the snap-buckling of functionally graded multilayer graphene platelet-reinforced composite curved beams with geometrical imperfections on the nanometer length. It is supposed that graphene platelets (GPLs) are uniformly distributed and randomly oriented in each layer, while its weight fraction varies from one layer to another based on various functionally graded patterns. The effective material properties of functionally graded multilayer GPLRC beams are evaluated via the model of the Halpin-Tsa. In the theoretical framework of the nonlocal strain gradient theory (NSGT) and the surface elasticity theory, a generalized nonlinear size-dependent curved beam model is established. The novel model includes not only a nonlocal parameter and a material length scale parameter of NSGT but also three surface constants of the surface elasticity theory, which can explore the coupling effect of nonlocal stress, strain gradient and surface energy on the snap-buckling of nanoarches. Furthermore, the present model can be transformed into the Euler-Bernoulli shallow arch model, the Timoshenko shallow arch model as well as the Reddy's higher-order shear deformation shallow arch model by choosing the appropriated shape function. Next, On the basis of the principle of Hamilton, the nonlinear governing equations of curved nanobeams are derived. Then to obtain the analytical solution of snap-buckling of curved beams, the nonlinear equations are solved by a two-step perturbation method. Finally, a detailed parametric study is carried out based on the analytical solution, aiming at analyzing the influences of respective physical parameters on the snap-buckling of such nanostructure.

Characterizations of welding mode transformation process during 1-μm and 10-μm laser welding

To reveal the enhancing energy coupling effect of plasma, a comparison of the welding mode transformation process during 1-µm and 10-µm laser welding of aluminum alloys is carried out through experimental observation and theoretical analysis. The heat conduction welding stage hardly exists in 10-µm laser welding and obviously exists in 1-µm laser welding. Alloy composition and surface roughness of the welded plate hardly influence the deep penetration welding threshold (DPWT) of the 10-µm laser, whereas they have a significant impact on that of the 1-µm laser. In addition, 1-µm laser welding and 10-µm laser welding have similar DPWTs. These phenomena are attributed to the formation of plasma near the workpiece surface during 10-µm laser welding owing to metal vapor breakdown by 10-µm laser irradiation. The plasma remarkably enhances the energy coupling between the 10-µm laser and workpiece by thermal conduction, and the DPWT of the 10-µm laser is thus reduced to approximately equal to that of the 1-µm laser.

Experimental study on the effect of the Coupling of Ignition Energy and pressure on the explosion limit of Coal-bed methane

Coal-bed methane(CBM)was a natural gas occurring in underground coal seams, which was mainly composed of methane. In order to study the effect of ignition energy and pressure on the explosion limit of CBM, a special environment 20L explosion characteristic test system was used. The explosion limit of methane under different ignition energy(10∼400J)and pressure (0.1∼1.2MPa)was studied experimentally. The results show that with the increase of ignition energy and initial pressure, the upper limit of methane explosion was obviously increased, the lower limit of explosion was decreasing, and the range of explosion limit was enlarged. Compared with the lower limit of methane explosion, the effect of ignition energy and initial pressure on the upper limit of methane explosion was more obvious. The coupling effect of ignition energy and initial pressure on the explosion limit of methane was greater than that of a single factor, and the effect of ignition energy and initial pressure on the explosion limit was more significant than that of a single factor.

Coupling effect of surface energy and dispersion forces on nonlinear size-dependent pull-in instability of functionally graded micro-/nanoswitches

In this paper, an integrated nonclassical multi-physics model is developed to study the coupling effect of surface energy and local microstructure on the nonlinear size-dependent pull-in instability of electrostatically actuated functionally graded material (FGM) micro-/nanoswitches. The developed model incorporates the influences of fringing field, dispersion Casimir or van der Waals force in addition to residual axial stress and mid-plane stretching. For more accurate analysis of the FGM switches, a nonclassical beam model is developed based on the Euler–Bernoulli beam theory in conjunction with the modified couple stress theory and Gurtin–Murdoch surface elasticity theory to account for the size dependency and surface energy effects, respectively. Material properties of both bulk and surface layers of the FGM switch are assumed to vary according to a power law distribution through thickness. To this end, the Hamilton principle is employed to derive the nonlinear size-dependent governing integral–differential equations and the associated nonclassical boundary conditions, without neglecting any terms raised by surface energy. The size-dependent relations are derived in general form, which can be reduced to those based on different elasticity theories, including surface energy theory, modified couple stress and classical theories. The resulting nonlinear integral–differential equations are solved utilizing the generalized differential/integral quadrature method, in which the nonclassical boundary conditions are exactly implemented for different immovable ends. The obtained results are compared with the results available in the literature to valid the efficiency of the present solution method. A numerical analysis reveals that the nonlinear pull-in voltage of FGM micro-/nanoswitches is significantly influenced by the FGM’s gradient index, length scale parameter, surface energy, residual axial stress, initial gap, slenderness ratio, and dispersion forces for different immovable boundary conditions.

Analysis of Medium- and Long-term Coupling Effect of Energy- and Water-Saving Policies in Urban and Rural Areas in Beijing

Analysis of Medium- and Long-term Coupling Effect of Energy- and Water-Saving Policies in Urban and Rural Areas in Beijing

Hydropower system operation stability considering the coupling effect of water potential energy in surge tank and power grid

This paper aims to study the hydropower system operation stability considering the coupling effect of water potential energy in surge tank and power grid. Firstly, the mathematical formulation for hydropower system with surge tank that connected to power grid is established. Then, the hydropower system operation stability is investigated. The coupling effect mechanism of surge tank and power grid on stability is revealed. Finally, the formula for critical stable sectional area (CSSA) of surge tank considering power grid is derived and analyzed. The results indicate that the free vibration equation for hydropower system with surge tank that connected to power grid under step load disturbance is a ninth order linear homogeneous differential equation. The domain at the bottom left corner of the critical line on the Proportional-Integral plane is the stable domain. The proposed novel analytic solution of stable domain has a high precision and is feasible for practical applications. The formula for CSSA of surge tank considering power grid realizes the unity of the coupling effect of water potential energy in surge tank and power grid. The CSSA contains four terms, i.e. headrace tunnel term, penstock term, governor term and power grid term.

Coupling effect of water temperature and light energy on the algal growth in Lake Taihu

环境因素对藻类生长的影响机制是探讨蓝藻水华暴发的基础，其中水温和光能均是影响藻类生长的关键物理因子.基于2015年春季于太湖观测的11次藻类总初级生产力、水温廓线和营养盐浓度等，探讨水温、光能及营养盐对藻类生长过程的影响.结果表明：春季，水温、光能是影响藻类生长的关键因素，而营养盐的影响贡献相对较弱.深层水体中光能是藻类生长的关键性限制因子，浅层表现为水温、光能的共同影响，而表层主要表现为光能的抑制.水温的升高促进藻类对光能的获取和利用，提高光抑制的光能阈值，造成深层水体中光能限制程度的加强，藻类生长呈现光限制的深度变浅.本研究有利于确定气候变化下水生生态系统演变的方向，为水生生态系统的恢复提供理论依据.;The effect of environmental factors on the gross primary production of phytoplankton is a basis for understanding the cyanobacteria bloom. Hereinto, water temperature and light energy are the key physical factors affecting phytoplankton growth. Based on phytoplankton primary productivity, water temperature profile and nutrient concentration observed in Lake Taihu in the spring of 2015, we explored the effects of these environmental factors on the the algae gross primary production. Results showed that in spring, water temperature and light energy were the key factors affecting algae growth, but the effect of nutrient was relatively weak in deep layers. The light energy and water temperature jointly affected the gross primary production of phytoplankton in shallower layer. The production were inhibited by light energy in surface layer. The water temperature increase promoted the ability of algae for the acquisition and utilization of light, improved the threshold value of light limitation, and enhanced the effect of light limitation, and shallowed the photo-inhibition depth. Current study is helpful to determine the evolution direction of aquatic ecosystems under climate change, and to provide an approach for the aquatic ecosystems restoration.

Enhancement of emission and directionality of Light Emitting Diode using Surface Plasmon Resonance

Emission of the LED can be enhanced by Surface Plasmons Resonance (SPRs), which are electron oscillations that can exist at the interface between a metal and dielectric materials. The mechanism is reliant upon the energy coupling effect between the emitted photons from the semiconductor and arranged metallic nanoparticles. The focus of this theoretical investigation is study the interaction between light and the metallic film, explicitly Ag and Au, deposited onto the surface of a light emitting diode (LED), which is proposed to allow coupling between surface plasmons and free-space photons. Moreover, it’s also demonstrated how the optical emission from a typical light of LED device can be spatially controlled through the deposition of a periodically structured metallic film. This theoretical investigation indicated that high-efficiency and spatially controlled direction light emission can be predicted for light emitters. This can be done through the best selection of the proposed parameters (λ=547.6nm and ʌ=660nm) and area of overlapping the circles of wave vectors for light in free space and surface plasmons. It is also appeared that the coupling between the free photons and surface plasmons is optimumfor the proposed wavelengths

Photonic crystal frequency band selecting and power splitting devices based on the energy coupling effect between waveguides

The photonic crystal power splitter based on the energy coupling effect between waveguides has the advantages of compact structure, wide bandwidth, low bending loss, large angle of separation, and no external electromagnetic interference. In this paper, the power splitting characteristics of two-dimensional triangular-lattice photonic crystal coupled waveguide are theoretically studied by using the finite-difference time-domain method, and a functional device is designed in order to achieve different output power ratios within different frequency ranges.In the two-dimensional photonic crystal structure with triangular lattice, we set two adjacent straight waveguides and the light beam is introduced from one of them. Because of the energy coupling effect between the two line defects, the light energy propagates alternately in them. Based on this principle, structures of different coupling lengths are simulated and the interference effect of each surface is considered. The device with the best coupling length is achieved for three different output energy propagating characteristics at different frequencies, which include three-division, two-division and single output cases. That is to say, the incident light beam within a frequency band travels through a particular waveguide; light in another frequency band only flows through the other two output waveguides; light in the third frequency band is assigned to all the three output waveguides equally. However, the frequency band width for the high-quality light beam splitting area as well as the transmittance contrast of the other two functional band areas are not very ideal.Based on the above numerical results, two transmission modes in the coupling waveguides are achieved by changing the cross section shape of the dielectric column in the coupling region and also by changing the connecting position between the output branch waveguide and the energy-coupling waveguide. Through the above change, the splitting performance is further optimized.By detecting and analyzing the relative intensity of the three output waveguides, we can determine the range of the incident light beam. Furthermore, the frequency ranges of the three different light output characteristics can be adjusted flexibly by changing the cross section shape of the dielectric column in the coupling region or by changing the connecting position of output waveguides. The functional device proposed in this paper has a high transmittance contrast ratio and a compact structure, which will promote the practical application of the all-optical functional devices in the fields of large-scale all-optical complex integration.

Time-resolved Kα spectroscopy measurements of hot-electron equilibration dynamics in thin-foil solid targets: collisional and collective effects

Time-resolved Kα spectroscopy measurements from high-intensity laser interactions with thin-foil solid targets are reviewed. Thin Cu foils were irradiated with 1−10 J, 1 ps pulses at focused intensities from 1018 to 1019 W cm−2. The experimental data show Kα-emission pulse widths from 3 to 6 ps, increasing with laser intensity. The time-resolved Kα-emission data are compared to a hot-electron transport and Kα-production model that includes collisional electron–energy coupling, resistive heating, and electromagnetic field effects. The experimental data show good agreement with the model when a reduced ponderomotive scaling is used to describe the initial mean hot-electron energy over the relevant intensity range.

Absorbance amplification using chromophore-nanoplasmon coupling for ultrasensitive protein quantification.

A plasmonic nanoscale Lycurgus cup array (nanoLCA), via near-field interaction with chromophores in commercial colorimetric biochemical assays, can drastically enhance assay sensitivity by over 2 orders of magnitude. A 96-microwell plate modified by placing the plasmonic nanoLCA on the well-bottom was used with the commercial Bradford protein quantification assay. Plasmons on the nanoLCA serve as an energy donor to matched resonance chromophores, and the near-field plasmonic energy coupling effect results in an increase in absorbance value at the plasmonic resonance wavelength. Even with a 5.1-fold reduced sample volume, a limit of detection enhancement factor of 200 is accomplished using the nanoLCA compared to using the conventional Bradford assay without plasmon aid. The nanoLCA-microplate sensing platform is readily scalable to 384- or 1536-microwell plates, which further reduces the sensing volume and boosts detection throughput with the enhanced sensitivity.

A Coordinated Routing Model with Optimized Velocity for Train Scheduling on a Single-Track Railway Line

Train scheduling aims to seek a set of space-time paths for multiple trains on a railway line such that resources can be utilized efficiently with respect to prespecified criteria. By representing the train trajectory through a time-space path in its space-time network, this paper proposes an integer programming model for train scheduling on a single-track railway line, in which velocity choice is particularly considered to further decrease the expected energy consumption and interactions between different trains, and the link energy consumption is derived by the Davis formula with respect to different train speeds. The proposed model is implemented in the GAMS optimization software to solve an approximate optimal solution. Numerical examples show that the optimal timetable with optimized velocities can further decrease the energy consumption and coupling effects in comparison to the fixed velocity based schedule.

Recent Advances of Light Propagation in Surface Plasmon Enhanced Quantum Dot Devices

Surface plasmons are of particular interest recently as their performance is approaching the enhancement of light emission efficiencies, after synthesized close to the vicinity of solid state materials, i.e., semiconductor structure. As other scientific works have been proposed to improve the light-emitting efficiency, such as the use of resonant cavities, photon recycling, and thin-light emitting layers with periodic surface texturing, surface plasmon possesses a promising way to the light enhancement, due to the energy coupling effect between the emitted photons from the semiconductor and the metallic nanoparticles fabricated by nanotechnology. The usual pathway of plasmon enhanced light emitting devices is the use of Ag/Au nanoparticles coating the surface of semiconductor quantum dot (QD) or quantum well (QW) structures. However, apart from efforts to extract as much light as possible from single-driven surface plasmon-QD/QW, it is possible to enhance the light emission rate with double optical-excitations. This approach is based on the quantum interference between the external lasers and the localized quantum light, and promised to stimulate the development of plasmon-enhanced optical sensors. In this review, we describe the quantum properties of light propagation in hybrid nanoparticle and semiconductor materials, i.e., quantum dot or nanomechanical resonator coupled to Ag/Au nanoparticles, driven by two optical fields. Distinct with single excitation, plasmon-assisted complex driven by two optical fields, exhibit specific quantum interference characteristics that can be used as sensitive all-optical devices, such as the slow light switch, nonlinear optical Kerr modulator, and ultra-sensitive mass sensing. We summarize the recent advances of light propagation in surface plasmon-enhanced quantum dot devices, driven by two optical fields, which would stimulate the development of novel optical materials, deeper theoretical insights, innovative new devices, and plasmonic applications with potential for significant technological and societal impact.