Energy Modulation Research Articles

Printable Energy Storage: Stay or Go?

In the era of rapidly evolving smart electronic devices, the development of power supplies with miniaturization and versatility is imperative. Prevailing manufacturing approaches for basic energy modules impose limitations on their size and shape design. Printing is an emerging technique to fabricate energy storage systems with tailorable mass loading and compelling energy output, benefiting from elaborate structural configurations and unobstructed charge transports. The derived "printable energy storage" realm is now focusing on materials exploration, ink formulation, and device construction. This contribution aims to illustrate the current state-of-the-art in printable energy storage and identify the existing challenges in the 3D printing design of electrodes. Insights into the future outlooks and directions for the development of this field are provided, with the goal of enabling printable energy storage toward practical applications.

Metabolic regulation of Shewanella oneidensis for microbial electrosynthesis: From extracellular to intracellular

Shewanella oneidensis MR-1 (S. oneidensis MR-1) has been shown to benefit from microbial electrosynthesis (MES) due to its exceptional electron transfer efficiency. In this study, genes involved in both extracellular electron uptake (EEU) and intracellular CO2 conversion processes were examined and regulated to enhance MES performance. The key genes identified for MES in the EEU process were mtrB, mtrC, mtrD, mtrE, omcA and cctA. Overexpression of these genes resulted in 1.5–2.1 times higher formate productivity than that of the wild-type strains (0.63 mmol/(L·μg protein)), as 0.94–1.61 mmol/(L·μg protein). In the intracellular CO2 conversion process, overexpression of the nadE, nadD, nadR, nadV, pncC and petC genes increased formate productivity 1.3-fold–3.4-fold. Moreover, overexpression of the formate dehydrogenase genes fdhA1, fdhB1 and fdhX1 in modified strains led to a 2.3-fold–3.1-fold increase in formate productivity compared to wild-type strains. The co-overexpression of cctA, fdhA1 and nadV in the mutant strain resulted in 5.59 times (3.50 mmol/(L·μg protein)) higher formate productivity than that of the wild-type strains. These findings revealed that electrons of MES derived from the electrode were utilized in the energy module for synthesizing ATP and NADH, followed by the synthesis of formate in formate dehydrogenase by the combinatorial effects of ATP, NADH, electrons and CO2. The results provide new insights into the mechanism of MES in S. oneidensis MR-1 and pave the way for genetic improvements that could facilitate the further application of MES.

VO2 Nanoparticles‐Based Thermochromic Smart Windows

AbstractVanadium dioxide (VO2) has reversible metal‐to‐insulator phase transitions (MIT) under thermal stimuli, which is a traditional and widely studied material for thermochromic smart window applications. Current research interests in VO2 materials design focused on decreasing phase change temperature (τc), increasing both luminous transmittance (Tlum) and solar modulating ability (▵Tsol). This review focuses on strategies for improving the thermochromic properties of VO2, including elemental doping to composite materials, improving the solar energy modulation ability, ameliorating color, elevating phase change efficiency, increasing durability, and enhancing energy efficiency. The challenges and opportunities of VO2 nanoparticles‐based thermochromic smart windows are discussed in the outlook section.

High mobility wide bandgap polymer realized by a combined modification strategy of processing solvent and dielectric interface

High mobility organic thin film transistors (OTFTs) are realized through a combined modification strategy of processing solvent and dielectric interface when a wide bandgap donor-acceptor conjugated polymer PBODT with edge-on orientation and high crystallinity was applied. The pre-aggregation ability of PBODT in different solvents exhibits different crystallinity but remains typical edge-on orientation. Moreover, the surface energy modulation of the semiconductor/dielectric interface enhances the transport property of PBODT, delivering a high mobility of 3.68 cm2V−1s−1. In addition, a comparable mobility of 3.06 cm2V−1s−1 is demonstrated via the eco-friendly solvent mesitylene. The results have demonstrated that the synergy of solvent and dielectric interface can provide new vitality for the application of high-performance environmentally friendly OTFTs.

Wireless, flexible, self-powered sensor to analyze head impact kinematics

This work presents a prototype of a wireless, flexible, self-powered sensor used to analyze head impact kinematics relevant to concussions, which are frequent in high-contact sports. Two untethered, paper-thin, and flexible sensing devices with piezoelectric-like behavior are placed around the neck of a human head substitute and used to monitor stress/strain in this region during an impact. The mechanical energy exerted by an impact force --varied in locations and magnitudes-- is converted to pulses of electric energy which are transmitted wirelessly to a smart device for storage and analysis. The wireless prototype system is presented using a microcontroller with an integrated Bluetooth Low Energy module. The static and dynamic characteristics of the transmitted signal are then compared to signals from accelerometers embedded in a head substitute, to map the sensor’s output to the angular velocity and acceleration during impacts. It is demonstrated that using only two sensors is enough to detect impacts coming from any direction; and that placing multiple external sensors around the neck region could provide accurate information on the dynamics of the head, during a collision, which other sensors fail to capture.

Computational procedure of solar irradiation: A new approach for high performance façades with experimental validation

Promoting sustainable strategies at the urban scale requires reliable assessment of solar irradiation received by buildings envelope. This will guide modelers, urban planners, and policymakers in optimizing building designs and incorporating renewable energy modules. Existing tools for irradiation prediction suffer from several limitations, including high computational burden and reliance on data availability, which can impact the tool's reliability. This paper advances a recently developed trigonometric model by the authors for irradiation prediction that effectively captures the details of the surrounding environment while maintaining accurate results, compared to pixel counting and polygon clipping techniques. The new model successfully accounted for the discontinuities in the surroundings profile and the presence of multiple rows of surrounding buildings. Beam, diffuse, and reflected irradiation were correlated to different density indicators such as ground-space index, floor-space index, and spaciousness index. A statistical model was applied to investigate the impact of key variables on the irradiation span and the feasibility of solar modules. The computation time per façade was significantly reduced from 6.1 min to 0.8 s, with an acceptable error of 5.1%.

Phonon engineering in Yb:La2CaB10O19 crystal for extended lasing beyond the fluorescence spectrum

Since the first invention of the laser in 1960, direct lasing outside the fluorescence spectrum is deemed impossible owing to the “zero-gain” cross-section. However, when electron-phonon coupling meets laser oscillation, an energy modulation by the quantized phonon can tailor the electronic transitions, thus directly creating some unprecedented lasers with extended wavelengths by phonon engineering. Here, we demonstrate a broadband lasing (1000–1280 nm) in a Yb-doped La2CaB10O19 (Yb:LCB) crystal, far beyond its spontaneous fluorescence spectrum. Numerical calculations and in situ Raman verify that such a substantial laser emission is devoted to the multiphonon coupling to lattice vibrations of a dangling “quasi-free-oxygen” site, with the increasing phonon numbers step-by-step (n = 1–6). This new structural motif provides more alternative candidates with strong-coupling laser materials. Moreover, the quantitative relations between phonon density distribution and laser wavelength extension are discussed. These results give rise to the search for on-demand lasers in the darkness and pave a reliable guideline to study those intriguing electron-phonon-photon coupled systems for integrated photonic applications.

Evaluating the climate projections for China through the lens of the simulations of planetary boundary layer height

The planetary boundary layer height (PBLH) plays an essential role in affecting many meteorological parameters in climate change, and it is closely associated with the concentration of near surface air pollutants as well. Uncertainty of simulating PBLH is large partly due to the complexity in the modulation of surface energy, and the behaviors of the climate models in reproducing PBLH have not been fully evaluated, which also limits the understanding of future changes in PBLH. Here by utilizing a multi-model ensemble of Coupled Model Intercomparison Project Phase 6 (CMIP6), we first thoroughly evaluate the capability of CMIP6 models in reproducing the spatial distribution of PBLH over China during the period of 1995–2014, revealing large discrepancies among the CMIP6 models. Meanwhile, inaccuracy of simulated meteorological parameters can lead to large deviations of PBLH in models, among which sensible heat flux (SHFLX) and near surface relative humidity (RH) show stronger modulation effects. To enhance the confidence of future projections, we apply a method by selecting the five models with the smallest biases and a high signal-to-noise ratio, and the results indicate that changes in PBLH under shared socioeconomic pathways exhibit a dipole pattern in both summer and winter. Specifically, PBLH is projected to decrease over North China and increase over Central China and South China in summer, while in winter PBLH tends to increase stronger in southern China and weaker in the northern flank. To reveal the mechanism governing the PBLH, we find that changes of PBLH is closely associated with surface energy. SHFLX and near surface RH are the dominant factors shaping the changes in the spatial heterogeneity of PBLH in the future. This study has important implications for the improvement of surface energy and PBLH in climate models in order to effectively predict the future changes of air pollutants.

Toward a fully coherent tender and hard X-ray free-electron laser via cascaded EEHG in fourth-generation synchrotron light sources.

Free-electron-laser-based beamlines utilize fully coherent laser pulses with extremely narrow bandwidth allowing direct use of X-rays without monochromators. This could be very beneficial for all users of current and future fourth-generation diffraction-limited synchrotron light sources (DL-SLSs) who need narrowband full-coherence high-brightness X-ray pulses. Based on our previous finding, i.e. that separating the two stages of echo-enabled harmonic generation (EEHG) with a few extra bending-magnet sections provides an effective way to increase the momentum compaction of chicane 1, one can simultaneously achieve adequate prebunching at extremely high harmonics as well as keep the energy modulation to the ideal minimum. This could open the door for cascaded EEHG, toward fully coherent tender and hard X-ray wavelengths. Built on our compact design of a twin-pulse seeding electron beam with an adjustable delay and timing jitter at the level of a few femtoseconds, a cascaded EEHG can be implemented, which includes two EEHG beamlines, where the radiation pulse generated by the first beamline with harmonic h1 could be used as the input seed laser pulse to the second beamline with harmonic h2. Hence, the second radiator could potentially reach very high harmonics [h = h1(20)h2(25-100)] from 500 to 2000, corresponding to tender and hard X-ray wavelengths. It is demonstrated that the cascaded EEHG scheme is compatible with almost any current or planned fourth-generation DL-SLS, with significant benefits for space-limited storage rings in particular. The main advantage is that this scheme requires almost no change of the storage-ring lattice and is fully compatible with other beamlines. Current proposals for rings with much longer straight sections would add self-amplified spontaneous emission as another viable option for storage-ring-based free-electron lasers.

The Impact of Carbon Emission Trading on Renewable Energy: A Comparative Analysis Based on the CGE Model

This study examines the effects of carbon emission trading on renewable energy consumption in China. The research applies the CEEEA2.0 model to simulate the economic, energy, and environmental impacts of carbon trading from 2018 to 2030. The CEEEA2.0 model is a recursive dynamic computable general equilibrium model that incorporates multiple households, sectors, and an energy and environment module. Four scenarios are considered: the Business as Usual (BaU) scenario, the Emission Trading Scheme (ETS)-benchmark scenario, and the ETS-strengthened and ETS-enhanced scenarios. The findings reveal that carbon emission trading positively influences electricity consumption, resulting in a higher preference for renewable energy due to reduced price disparities between renewable sources and fossil fuels. Consequently, electricity generation from renewable sources increases in all scenarios compared to the BaU scenario. However, the share of renewable energy is not substantially affected by carbon emission trading due to the complex interplay of factors, including substitution and income effects. The study further highlights that carbon trading significantly reduces coal usage and partially increases the overall proportion of renewable energy. These results underscore the significance of establishing ambitious carbon reduction targets and continual efforts to shift towards clean energy sources.

Continuous photon energy modulation in IMRT of pancreatic cancer

Purpose: To develop a novel IMRT optimization method based on the principle of photon energy synthesis that simultaneously optimizes fluence map and beamlet energy. The method was validated on pancreatic cancers to demonstrate the benefits of the additional degree of freedom of photon energy in IMRT.Methods: Previous work has demonstrated that the effect of a photon beam of known energy can be achieved by the combination of two existing energy photons in the proper ratio. It further implied that any energy photon can be synthesized. Based on this, we propose the concept of continuous beamlet energy modulation in IMRT, or IMRT-BEM. The IMRT-BEM was modeled as the simultaneous optimization of two fluence maps, one for the low energy beam and one for the high energy beam, and it was implemented in an in-house inverse planning system. The IMRT-BEM was applied on 10 pancreatic cancer cases, where the IMRT-BEM plan was compared with single-energy IMRT plans of 6 MV (IMRT-6MV) and 15 MV photons (IMRT-15MV).Results: The IMRT-BEM plan provides a noticeable reduction to the volume irradiated at the high dose level (PTV105%) for PTV, at least 24.7% (6.4 ± 6.8 vs. 31.1 ± 18.7 (p = 0.005) and 43.8 ± 19.8 (p = 0.005) for IMRT-BEM, IMRT-6MV, and IMRT-15MV respectively). For target dose coverage, there were statistically significant improvements between the IMRT-BEM plans and the other two plans in terms of CI and HI. Compared to the IMRT-6MV plan, there were significant reductions in the Dmean of the spinal cord, liver, bowel, duodenum, and stomach. The irradiation volumes of the medium dose (V20Gy, and V40Gy) for the duodenum and bowel were reduced significantly. There were no significant differences between the IMRT-BEM and IMRT-15MV plans except for the Dmean of the spinal cord and the duodenum, the V20Gy, and V40Gy for the duodenum, and the V20Gy of the stomach.Conclusion: IMRT-BEM has certain dosimetric advantages for PTV and improves OAR sparing in pancreatic cancer, and can be effectively used in radiation treatment planning, providing another degree of freedom for planners to improve treatment plan quality.

Collective magnetic Higgs excitation in a pyrochlore ruthenate

The emergence of scalar Higgs-type amplitude modes in systems where symmetry is spontaneously broken has been a highly successful, paradigmatic description of phase transitions, with implications ranging from high-energy particle physics to low-energy condensed matter systems. Here, we uncover two successive high temperature phase transitions in the pyrochlore magnet Nd2Ru2O7 at TN = 147 K and T* = 97 K, that lead to giant phonon instabilities and culminate in the emergence of a highly coherent excitation. This coherent excitation, distinct from other phonons and from conventional magnetic modes, stabilizes at a low energy of 3 meV. We assign it to a collective Higgs-type amplitude mode, that involves bond energy modulations of the Ru4 tetrahedra. Its striking two-fold symmetry, incompatible with the underlying crystal structure, highlights the possibility of multiple entangled broken symmetries.

Geothermal-solar energy system integrated with hydrogen production and utilization modules for power supply-demand balancing

The power generation of geothermal energy is severely restricted by its low grade and limited flexibility. We propose integrating geothermal and solar energy and introducing hydrogen energy modules to achieve a flexible and highly efficient renewable power supply for communities. The comprehensive thermodynamic models of the proposed combined system are established, and the daily performance of the system is simulated and analyzed based on a power supply-demand matching strategy. From the results, the switching points of hydrogen generation/consumption mode occur at 6 h and 18 h. During the day time, the system's overall energy efficiency varies between 13.28% and 14.36%, representing a significant improvement compared to the previous geothermal-solar combined system only with 5.67% energy efficiency. Then, the effects of geothermal water temperature and solar radiation intensity on the system's daily performance are analyzed, showing the daily net hydrogen production amount increases from −28.71 kg to 306.24 kg with the improved geothermal grade. Finally, the fluctuant electricity profiles of two typical communities are taken into the simulation for case analysis. The good demand-supply matching results for both cases showcase the dynamic capture ability of the models and validate the applicability of the proposed system.

A bi-directional beam-line energy ramping for efficient patient treatment with scanned proton therapy

Objective. The treatment of mobile tumours using Pencil Beam Scanning (PBS) has become more prevalent in the last decade. However, to achieve the same beam delivery quality as for static tumours, treatments have to be combined with motion mitigation techniques, not limited but including, breath hold, gating and re-scanning, which typically prolong treatment time. In this article we present a novel method of bi-directional energy modulation and demonstrate our initial experience in improvement of treatment efficiency. Approach. At Paul Scherrer Institute Gantry 2 mobile tumours are treated by combining PBS with gating and volumetric re-scanning (VR), where the target volume is irradiated multiple times. Initial implementation of VR used only descending beam energies, creating a substantial dead time due to the beam-line initialization (ramping) before each re-scan. In 2019 we commissioned an energy meandering strategy that allows us to avoid beam line ramping in-between energy series while maintaining beam delivery quality. Main results. The measured beam parameters difference for both energy sequence are in the order of the typical daily variations: 0.2 mm in beam position and 0.2 mm in range. Using machine log files, we performed point-to-point dose difference calculations between original and new applications where we observed dose differences of less than 2%. After three years of operation employing bi-directional energy modulation, we have analysed the individual beam delivery time for 181 patients and have compared this to simulations of the timing behaviour assuming uni-directional energy sequence application. Depending on treatment complexity, we obtained plan delivery time reductions of up to 55%, with a median time gain of 17% for all types of treatments. Significance. Bi-directional energy modulation can help improving patient treatment efficiency by reducing delivery times especially for complex and specialised irradiations. It could be implemented in many existing facilities without significant additional hardware upgrades.

A Hybrid Submodule Three-Phase Multiplexing Arm Modular Multilevel Converter With Wide Operation Range and DC-Fault Blocking Capability

Three-phase multiplexing arm modular multilevel converter (TPMA-MMC) possesses lower cost, smaller volume, and higher efficiency compared with MMC. However, the limited operation range limits its popularity. Hence, in this article, it redefines arm submodule (SM) configuration type, where the conventional arm is configured with full-bridge submodules (FBSMs), and the multiplexing arm is formed by half-bridge submodules (HBSMs). Meanwhile, a new energy balance principle and modulation scheme are proposed to expand TPMA-MMC’s operation range. Furthermore, the DC-fault blocking schemes could be implemented to realize DC-fault tolerance reliably without the multiplexing arm blocking. Compared with hybrid MMC(H-MMC), it could reduce by 33.33% in submodules a least, which leads lower footprint and operation loss. Due to reregulating the energy flowing path of multiplexing arm, and rearranging the chain-link voltage of multiplexing and conventional arm, it could reduce the required SM capacitance and further decrease 65% energy storage requirement, resulting in improving the power density. Finally, the topology control scheme and DC-fault blocking scheme are verified by simulation and scale-down prototype experimental results.

Synergistic effect of energy filtering, modulation doping and boundary scattering of multiphase Cu-Sb-Bi-S system for enhanced thermoelectric performance

In this a multiphase cubic system has been successfully synthesised by solvothermal method. The profile fitting using Rietveld refinement confirms the phase fraction of monoclinic-Cu4Bi5S10, orthorhombic-Cu3BiS3, orthorhombic-Sb2S3 and tetragonal- Cu3SbS4 as 54.56%, 40.33%, 2.96%, 2.15%, respectively. Further, the presence of multiphase was additionally confirmed using HR-TEM analysis from observing the various patterns of atomic arrangement in the lattice plane. Moreover, a narrow band gap of 0.64 eV was confirmed using UV-DRS analysis. Electrical transport properties such as the Seebeck coefficient and electrical conductivity has been determined using ZEM-3 measurement which depicts the negative value of the Seebeck coefficient that conforms to the negative charge carrier transport. Interestingly the very low thermal conductivity of 0.37 Wm−1K−1 at 303 K is observed for the S2 sample. Overall, with enhanced electrical conductivity of 59.7 S.cm−1 at 473 K, and Seebeck coefficient of 60.3 μVK−1 at 353 K leads to a maximum ZT of 0.0068 at 473 K, which is due to the synergistic effects of boundary phonon scattering, energy filtering and modulation doping effect in the multiphase Cu-Bi-Sb-S system.

Controllable Optical Features of Multiple‐Layered Axial Heterostructure Nanorods for Multicolor Polariton Nanolasers

AbstractThe optical features of multiple‐layered axial heterostructures composed of III‐nitride semiconductors (GaN, InGaN, and AlGaN) are investigated to realize tunable nanolasers. The optical confinement effects develop exciton‐polariton in nanorods, leading to polariton lasing with distinctive dispersion. The lasing characteristics in the heterostructure are similar to those in the homostructure, although the carrier transfer between layers influences the optical gain. The energy‐dependent property of polariton changes the mode spacing of lasing peaks. The alloyed systems of InGaN can tune the color of lasing in the visible region, while the lasing of AlGaN is also achievable in the optimized configuration. The polarization of lasing indicates the predominant contribution of the fundamental transverse mode. Therefore, in the multiple‐layered heterostructure, controllable triple‐color lasing using the feature of polariton, modulation of band gap energy, and the amplification process of the waveguide is demonstrated for the first time, with the tunable color over a wide range of the visible region. Multicolor polariton nanolasers offer a promising path to diverse nanophotonic devices with controllable optical characteristics.

Improved anti-adhesive wear performance of rail/armature pair via interfacial energy modulation for electromagnetic launching applications

The prevention of adhesive wear between rail (made of high-strength Cu alloy) and armature (made of 7075 Al alloy) in the electromagnetic launching system is challenging due to the strong adhesion forces that arise from the interaction of asperities. Here, we propose a novel approach to enhance the anti-adhesive wear performance of rail through interfacial energy modulation between rail/armature pair for electromagnetic launching applications. Our findings indicate that the interfacial energy of the rail/armature pair can be significantly reduced by magnetron sputtering a W thin film onto the Al alloy surface. A lower coefficient of friction and a substantial alleviation in adhesion and mechanical damage of the Cu alloy are thus obtained. Molecular dynamics simulations reveal that the immiscibility and low interfacial energy of the Cu/W pair result in the formation of an amorphous interfacial layer during friction, facilitating countermotion at the contacting surfaces, thus in turn enables the low friction. The concept proposed in this work is further validated by real electromagnetic launching tests.

Spectral tailoring of the terahertz radiation from air plasma excited by two-color femtosecond pulses

We analyzed both experimentally and theoretically the spectrum of terahertz emission from air plasma excited by phase-controlled two-color femtosecond pulses. It was found that the low frequency component (<5 THz) exhibits high energy modulation contrast (>90%) for varied phase shift between the fundamental light field and its second harmonic, while the high frequency component (5–20 THz) was just slightly modulated with the phase shift. This proofs that the shape of the THz spectrum can be effectively tailored by changing the relative phase. To explain the experimental results, we developed a nonlocal plasma current approach, which was employed to calculate broadband spectral THz shapes and study their dependence on pulse parameters. It was revealed that the modulation contrast in the high-frequency part of the THz spectrum decreases with the pulse duration and the frequency detuning between the doubled fundamental frequency and the central frequency of the second harmonic field in the focal region. The obtained results indicate that the shape of the THz spectrum is affected by fine details of the frequency and phase structure of the two-color pulse, which can be used both for simple experimental tailoring of the THz spectrum and probing the two-color pulses undergoing lengthening and spectral shifts while propagating.

A Joint Clearing Model of Energy-Frequency Modulation Based on Flexible Block Order

The large-scale integration of renewable energy into the grid has led to a gradual diversification of power generation trading units on the power-side, with varying operational characteristics, costs, and trading needs among diverse power generation trading units. Traditional power system clearing models face challenges. Block order is a bidding type that allows for multiple volume–price combinations. At the same time, the randomness and volatility of renewable energy poses challenges to the safe and stable operation of the system. Building a power system clearing model that meets the diverse and flexible needs of the power system has become an important consideration. Therefore, this paper considers the design of three flexible energy blocks: a sustaining block, flux block, and adjustment block to meet the differential needs of diverse trading units and establishes a flexible block order clearing model. Secondly, it establishes a joint clearing model of electrical energy and frequency modulation (FM) to ensure the stable and reliable operation of the system, and solves the model based on relevant constraints to determine the winning electrical energy price and FM price. The CPLEX and Yalmip algorithms are used to solve the model. Finally, a case study was conducted based on an improved IEEE 14-bus system. The results showed that the model proposed in this paper can satisfy the differential needs of diverse trading units, effectively improve the renewable energy consumption capacity, and reduce the prices of the energy market and frequency modulation market. Also, the standard deviation of the net load of the system is relatively low, which improves the reliability of the power system’s operation.