Energy Transfer Research Articles

Assessment of dynamic responses and impact resistance of corrugated plate-reinforced concrete tunnels under irregular rockfall scenarios.

This article presents a composite tunnel rockfall protection structure (CPRC) employing galvanized corrugated steel plates as the inner formwork for reinforced concrete structures. It addresses the threats posed by frequent rockfall disasters in mountainous regions with complex geology. The research investigates impact damage from various rockfall shapes through numerical simulations and experiments on five representative forms, comparing traditional reinforced concrete structures RC with CPRC. The study highlights both structures' dynamic responses and damage characteristics across different impact scenarios, introducing the Residual Resistance Index RRI as a measure of post-impact safety performance. Results show that the numerical simulations align with laboratory tests, with discrepancies within 10%, validating the simulation method's accuracy in predicting impact resistance. Following impacts, both structures primarily displayed brittle concrete damage; however, the CPRC structure demonstrated a 79.46% reduction in concrete damage and an 86.31% decrease in reinforcement damage. The energy-dissipating properties of the corrugated plates significantly lowered rockfall penetration depth and impact energy transfer ratio, with an RRI exceeding 0.88 post-event. Additionally, the study reveals varying damage effects from different rockfall shapes, further supporting the CPRC structure's superior impact resistance and its effectiveness in preventing secondary disasters in tunnel engineering within mountainous terrains.

Quantum phenomena in biological systems

Quantum biology is a modern field of research that aims to understand how quantum effects can affect the chemistry underlying various biological processes. This paper reviews several examples of biological processes where quantum effects might play a notable role. Initially, the photon capture mechanism present in vision is discussed, where the energy of the photon is used to cause conformational changes to chromophoric proteins. The second example elaborates the highly efficient energy transfer process present in photosynthesis and discusses, in particular, how the random quantum walk process may enhance the performance drastically. Subsequently, the vertebrate magnetoreception, and the possible associated role of the radical pair mechanism in the process is considered. The review concludes with the discussion of some speculative ideas of putative quantum effects arising in neural processes.

Nonlinear Tide‐River‐Surge Interactions and Their Impacts on Compound Flooding During Typhoon Hato in the Pearl River Delta

AbstractIn coastal areas, multiple hydrodynamic processes co‐occur, including the astronomical tide, river discharge, and storm surge. Their propagation and interaction within coastal tidal river result in strong nonlinear behavior in inland areas. This study employed a hydrodynamic model and continuous wavelet transform analysis to investigate the complex tide‐river‐surge interactions and their impacts on compound flooding in the West River of the Pearl River Delta during an extreme typhoon event. Validated model outputs provided insights into the spatial and temporal variations of river discharge, water levels, and currents. Wavelet analysis revealed river discharge modulates tidal properties, causing nonstationary tides and asymmetries, with high flows suppressing tidal ranges but facilitating energy transfers to overtides. During Typhoon Hato, storm surges dominated high‐frequency water level fluctuations that rapidly propagated upstream. Crucially, strong high‐frequency tide‐river‐surge coupling induced significant water level amplifications, with interaction intensities increasing landward. In upstream areas where riverine and coastal drivers converged, flood risks exceeded typical estimates due to this vigorous multi‐driver compounding. Findings highlighted how existing flood mitigation approaches over simplistically superposing individual sources may severely underestimate flood levels by neglecting such nonlinear interactions. A comprehensive accounting of the cumulative, multiplicative effects of tides, discharge, storm surge, and sea level rise is imperative. This quantitative unraveling of key physical drivers offers transferable insights applicable to compound flood risk evaluations and policy guidance for enhancing resilience in other estuary and delta regions. Future work should focus on holistically modeling multivariate extremes and their interactions.

Fluorescent Carbon Dots with Red Emission: A Selective Sensor for Fe(III) Ion Detection

We present a procedure for the synthesis and purification of p-phenylenediamine-based carbon dots that can be used for the recognition of Fe(III) ions. Carbon dots have an approximately spherical shape with an average size of 10 nm and are composed of a carbonaceous core surrounded by functional groups attached to it, both of which are responsible for their dual fluorescence properties. The emission bands have a different behavior, with a blue band dependent and a red emission independent of the excitation wavelength, respectively. Red emission is appropriate for the detection of ions and other molecules in biological environments because this high wavelength prevents the occurrence of processes such as resonance energy transfer and internal filter effects. In particular, the presence of Fe(III) ions produces an important quenching phenomenon that can be applied to the fabrication of a sensor. The platform is very sensitive, with a detection limit of 0.85 µM, which is within the lowest values reported for this ion, and a high selectivity that is believed to be due to the formation of a specific complex in the ground state through specific interactions of Fe (III) ions with pyridinic and amino groups on the surface of the nanomaterials.

Photoredox-Catalyzed Markovnikov Hydroamination of Alkenes with Azoles.

A visible-light induced intermolecular hydroamination of alkenes with azoles is reported, delivering pharmaceutically valuable N-benzyl azoles in high yields with excellent Markovnikov selectivity. Mechanistic studies suggest that the process is initiated by the energy transfer of the excited photocatalyst with alkenes, followed by the single electron reduction, protonation, and subsequent single electron oxidation to afford the key alkyl carbocation intermediate. This protocol exhibits advantages of broad functional group tolerance, excellent atom economy, high efficiency, and mild reaction conditions.

Synthesis and characterization of new organometallic lanthanides metal complexes for photodynamic therapy

New Schiff base ligand: 4-methoxy salicaldhyde-2-2-phenyl-hydrazono acetaldehíyde prepared by facile method. The molecular structures characterized by elemental analysis and proton magnetic resonance spectra (1H-NMR spectra). This spectra at the chemical shifts (3.5–10.39 ppm) confirmed the types and the numbers of protons. The sharp melting point at the range 110–112 °C confirmed purity. New optically active metal (samarium, terbium and gadolinium) complexes of the Schiff base synthesized in a one pot reaction. Vibrational IR spectra confirmed functional groups. Scanning electron microscopy micrographs confirmed that the modified microstructure of the metal complexes differed in morphology than the ligand. Powder X-ray diffraction patterns confirmed good crystalline structure. The optically activity of the solid metal complexes confirmed from electronic absorption spectra. The UV absorbance band at the wavelength range 280–390 nm and the intense phosphorescence bands up to 830 nm enabled application in photo dynamic therapy for apoptosis cancer cells by conversion triplet oxygen in the tissues into reactive singlet oxygen. Low charge transfer energy: 2.59–2.61 eV, high molar extinction coefficients (ε) at the order of magnitude \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:{10}^{6}$$\\end{document} M− 1 cm− 1 and the intense phosphorescence bands reflected good photodynamic activity. The metal complexes are thermally stable.

Prevention of Overhead Shoulder Injuries in Throwing Athletes: A Systematic Review

(1) Background: Shoulder pathologies are mostly found in overhead sports. Many risk factors have been identified, in particular a deficit in the kinetic chain. The aim of this review was to find out whether prevention by strengthening the kinetic chain can have an impact on the rate of shoulder injury in overhead pitching athletes. (2) Methods: A systematic review of the literature was carried out, including studies on the role of the kinetic chain in the prevention of overhead athletes. The studies used were works published over the last 10 years searched on PubMed, Cochrane Library, PEDro and Science Direct. They were also analyzed by methodological quality scales: the PEDro scale and the Newcastle–Ottawa scale. (3) Results: Eight studies met the inclusion criteria. The studies analyzed revealed a significant correlation between the use of the kinetic chain and the prevention of shoulder injuries, associating factors such as muscle strength, physical performance in tests (CMJ, FMS), static and dynamic balance and the ability to transfer energy from the lower to the upper body. (4) Conclusions: It is important to integrate core stability work and lower limb strengthening to minimize excessive stress on the shoulder complex, while optimizing force production and performance.

Efficient Energy Transfer Enabled by Dark States in van der Waals Heterostructures.

Dark exciton states show great potential in condensed matter physics and optoelectronics because of their long lifetime and rich distribution in band structures. Therefore, they can theoretically serve as efficient energy reservoirs, providing a platform for future applications. However, their optical-transition-forbidden nature severely limits their experimental exploration and hinders their current application. Here, we demonstrate a universal dark state nonlinear energy transfer (ET) mechanism in monolayer WS2/CsPbBr3 van der Waals heterostructures under two-photon excitation, which successfully utilizes the enormous energy reserved in the dark exciton state of CsPbBr3 to significantly improve the photoelectric performance of monolayer WS2. We first propose the scenario of resonant ET between the dark state of CsPbBr3 and WS2, and then reveal that this is a typical Förster resonant ET and belongs to the 2D-2D category. Interestingly, the dark state ET in CsPbBr3 is identified as a long-range donor-bridge-acceptor hopping mode, with a potential distance exceeding 200 nm. Finally, we successfully achieve nearly an order of magnitude enhancement in the near-infrared detection performance of monolayer WS2. Our results enrich the theory of dark exciton states and ET, and they provide a way of using dark exciton states for future practical applications.

Efficient Energy Transfer from Quantum Dots to Closely‐Bound Dye Molecules without Spectral Overlap

Quantum dots (QDs) are semiconductor nanocrystals whose optical properties can be tuned by altering their size. By combining QDs with dyes we can make hybrid QD‐dye systems exhibiting energy transfer (ET) between QDs and dyes, which is important in sensing and lighting applications. In conventional QDs that need a shell to passivate surface defects, ET usually proceeds through Förster resonance energy transfer (FRET) that requires significant spectral overlap between QD emission and dye absorbance, as well as large oscillator strengths of those transitions. This considerably limits the choice of dyes. In contrast, perovskite QDs do not require passivating shells for bright emission, which makes ET mechanisms beyond FRET accessible. This work explores the design of a CsPbBr3 QD‐dye system to achieve efficient ET from CsPbBr3 QDs to dyes with dimethyl iminium binding groups where the close binding of dyes surface facilitates spatial wavefunction overlap. Using steady‐state and time‐resolved photoluminescence experiments, we demonstrate that efficient ET from CsPbBr3 to dyes with minimal spectral overlap proceeds via the Dexter exchange‐type mechanism, which overcomes the conventional restriction of spectral overlap that severely limits the tunability of these systems. This approach opens new avenues for QD‐molecule hybrids for a wide range of applications.

Efficient Energy Transfer from Quantum Dots to Closely-Bound Dye Molecules without Spectral Overlap.

Quantum dots (QDs) are semiconductor nanocrystals whose optical properties can be tuned by altering their size. By combining QDs with dyes we can make hybrid QD-dye systems exhibiting energy transfer (ET) between QDs and dyes, which is important in sensing and lighting applications. In conventional QDs that need a shell to passivate surface defects, ET usually proceeds through Förster resonance energy transfer (FRET) that requires significant spectral overlap between QD emission and dye absorbance, as well as large oscillator strengths of those transitions. This considerably limits the choice of dyes. In contrast, perovskite QDs do not require passivating shells for bright emission, which makes ET mechanisms beyond FRET accessible. This work explores the design of a CsPbBr3 QD-dye system to achieve efficient ET from CsPbBr3 QDs to dyes with dimethyl iminium binding groups where the close binding of dyes surface facilitates spatial wavefunction overlap. Using steady-state and time-resolved photoluminescence experiments, we demonstrate that efficient ET from CsPbBr3 to dyes with minimal spectral overlap proceeds via the Dexter exchange-type mechanism, which overcomes the conventional restriction of spectral overlap that severely limits the tunability of these systems. This approach opens new avenues for QD-molecule hybrids for a wide range of applications.

An efficient control scheme for operational performance enhancement of vehicular fuel cell integrated power system

Recent advancements in fuel cell (FC) technology have positioned it as a promising alternative energy source across various stationary, mobile, and transportation applications. As fuel cell vehicles (FCVs) become increasingly prominent in the transportation sector, they also offer the potential to function as supplementary stationary energy providers when parked, thereby contributing to the grid. In this study, a control method to enhance the energy transfer capability of an FCV-integrated grid system is proposed. To manage energy transfer between grid and FCVs, classical strategies using fixed parameter controllers suffer from performance degradation due to the nonlinear and external parameter-dependent nature of the FC stacks. The proposed adaptive fractional-order proportional-integral strategy bears the advantage of self-tuning parameters feature for designing the control parameters of power conditioning unit. Using fractional-order control endows the system with memory and heredity, enhancing its ability to handle nonlinearity and uncertainty. Through case studies, it is demonstrated that the proposed strategy reduces vehicular FC output power variations by over 60 % while enhancing transient response by 50 % compared to classical control methods. Thus, the limitations such as low control flexibility, slow transient response, and high undershoot/overshoot rates addressed by the classical controllers are countered thanks to the developed strategy.

The Main Groups of Photosynthetic Bacteria and Photosynthetic Pigments

Photosynthesis is one of the most important process on today’s Earth, which provides most of the energy source of the Earth’s biosphere, changed and shaped the atmosphere and oceans in early days of the Earth. Photosynthetic bacteria are a kind of prokaryotic microorganism that can assimilate or dissimilate by using light energy as an energy source and organic or inorganic matter as the electron donor for assimilation or heterocytosis, which can be divided into Cyanobacteria, Purple bacteria (PB), Green bacteria (GB), Aerobic anoxygenic photosynthesis bacteria (AAPB) and others. In this paper, the literature on photosynthetic bacteria in recent years is reviewed and combined with the latest astrobiology research, revealing the photosynthetic pigment composition of different photosynthetic bacteria. Cyanobacteria contain Chlorophyll (Chl) for the absorption and transfer of light energy including Chl a, CHl b, Chl d, carotenoids and phycobilins, of which chlorophyll b and chlorophyll d are not contained in all types of cyanobacteria, PB contain BChl a or BChl b, GSB contains photopigments BChl a, Chl a, and BChl c, d, or e, GNSB contains photopigments BChl a and/or BChl c, and AAPB mainly contain BChl a. Understanding how Photosynthesis evolves, what kinds of photosynthetic pigments and how do it function could provide a new insight into the origins of life and are beneficial to detection of extraterrestrial life and potential habitable planets.

Three-component soliton states in spinor F = 1 Bose-Einstein condensates with PT-symmetric generalized Scarf-II potentials

Abstract Introducing PT-symmetric generalized Scarf-II potentials into the three-coupled nonlinear Gross-Pitaevskii equations offers a new way to seeking stable soliton states in quasi-one-dimensional spin-1 Bose-Einstein condensates. In scenarios where the spin-independent parameter c_0 and the spin-dependent parameter c_2 vary, we use both analytical and numerical methods to investigate the three-coupled nonlinear Gross-Pitaevskii equations with PT-symmetric generalized Scarf-II potentials. We obtain analytical soliton states and find that simply modulating c_2 may change the analytical soliton states from unstable to stable. Additionally, we obtain numerically stable double-hump soliton states propagating in the form of periodic oscillations, exhibiting distinct behavior in energy exchange. For further investigation, we discuss the interaction of numerical double-hump solitons with Gaussian solitons and observe the transfer of energy among the three components. These findings may contribute to a deeper understanding of solitons in Bose-Einstein condensates with PT-symmetric potentials and may hold significance for both theoretical understanding and experimental design in related physics experiments.

Kinetic Alfvén wave cascade in sub-ion range plasma turbulence

Kinetic Alfvén waves (KAWs) are simulated with a 3D particle-in-cell (PIC) code by using the eigenvector relations of density, velocity, electric, and magnetic field fluctuations derived from a two-fluid KAW model. Similar simulations are also performed with a whistler waves setup. The 2D two-fluid eigenvector relations are converted into 3D by using rotation of the reference frame. The initial condition for the simulations is a superposition of several waves at scales slightly larger than the ion skin depth. The nonlinear interactions produce a transfer of energy to smaller scales. The magnetic field perturbation ratios, velocity perturbation, and density perturbation ratios are calculated from the simulation at higher wavenumbers and compared with the analytically expected ratios for KAWs and whistler waves. We find that in both types of simulations, initialized either with an ensemble of KAWs or with whistlers, the observed polarization relations at later times match better with the KAW relations compared to whistlers. This indicates a preference for excitation of KAW fluctuations at smaller scales. The power spectrum in the perpendicular direction is calculated, and it shows similar indices as measured in the solar wind power spectrum in the transition (sub-ion) region. The power law extends to smaller scales when a higher ion-to-electron mass ratio is taken. The 2D magnetic power spectrum in magnetic field parallel and perpendicular directions shows typical anisotropy where the power spreads more in the perpendicular direction than in the parallel direction. This study shows that KAWs can explain features of the sub-ion range plasma turbulence in the solar wind.

Quantum–Chemical Study of the Photophysical Behavior of Mesogenic Europium(III) Complexes with β‐Diketones and Lewis Bases

AbstractMetal‐containing liquid crystals such as Ln(III) complexes possess unique structural, liquid‐crystalline (LC), optical, and magnetic properties and represent modern cutting‐edge multifunctional materials. Application of mesogenic Ln(III) complexes is hindered by their nontrivial structure–property relationships. These relationships, in turn, depend on various factors, including insufficiently studied physicochemical processes. Although a proper Ln(III) element and the respective ligand environment are selected prior to synthesis of such complexes, the structural features of the coordination polyhedra, especially upon photoexcitation, are not uniquely defined. Therefore, this work focuses on the development of theoretical approaches to creating multifunctional materials represented by highly luminescent mesogenic Eu(III) complexes with β‐diketones and Lewis bases. The relationships between their structure, the parameters of Voronoi–Dirichlet polyhedra, the luminescence efficiency, and the LC properties were considered. The calculated excited states and intramolecular energy transfer rates were used to determine intramolecular energy transfer channels. The LC behavior of the studied materials was shown to mainly depend on the ligand environment, whereas their optical properties were found to be mostly governed by the coordination polyhedra.

StaR-LIF: State-resolved laser-induced fluorescence modeling for diatomic molecules

This study introduced a new model for quantitative analysis of the state-resolved laser-induced fluorescence signal of diatomic molecules, namely StaR-LIF. This model is built upon a master equation of the collisional-radiative transfer processes, which incorporated the latest data on the collisional energy transfer rates between individual spin- and parity-resolved rovibronic quantum levels, together with the most recent updates on the energy levels, line strengths and broadening/shift parameters of the relevant absorption and fluorescence transitions. To facilitate the use of this model, a web-based graphic user interface has been developed and made available at https://starlif.pku.edu.cn. Example applications of the current model have been demonstrated for NO, OH and CH, including parametric studies on the effects of variable pulse width and saturating excitation, as well as the temporal evolution of fluorescence spectrum during collisional transfer. The StaR-LIF model can provide quantitative modeling and analysis capabilities over a wide range of gasdynamic and excitation conditions, and promises to be useful in future LIF studies of complex reacting flows.

Red emission enhancement in BaYF5:Eu3+ phosphor nanoparticles by Bi3+ co-doping

Herein, we report the photoluminescence properties of Bi3+-sensitized BaYF5:10 mol%Eu3+ nanoparticles. The emission spectra feature Eu3+ peaks corresponding to transitions from the 5D0 excited to 7FJ (J = 1, 2, 3, 4) lower levels with two dominant emissions positioned in the orange-red (∼ 592 nm, 5D0 → 7F1) and deep-red (∼ 697 nm, 5D0 → 7F4) regions. Upon 265 nm excitation, the emission intensity increases with an increase of Bi3+ concentration up to 20 mol%. Due to the energy transfer from Bi3+ to Eu3+ ions, the integrated intensity of Eu3+ emission in the Bi3+ co-doped BaYF5:10 mol%Eu3+ is 216% stronger than in the Bi3+-free sample. Our findings demonstrated that BaYF5:Eu,Bi has potential in plant lighting technology due to strong emission in red and deep-red spectral areas.

Receptor determinants for ß-arrestin functional specificity at C-X-C chemokine receptor 5 (CXCR5).

ß-arrestins are multi-faceted adaptor proteins that mediate G protein-coupled receptor (GPCR) desensitization, internalization, and signaling. It is emerging that receptor-specific determinants specify these divergent functions at GPCRs, yet this remains poorly understood. Here, we set out to identify the receptor determinants responsible for ß-arrestin-mediated regulation of the chemokine receptor CXCR5. Using bioluminescence resonance energy transfer (BRET) we show that ß-arrestin1 and ß-arrestin2 are dose-dependently recruited to CXCR5 by its cognate ligand CXCL13. The carboxy-terminal tail of CXCR5 contains several Ser/Thr residues that can be divided into 3 discrete phospho-site clusters based on their position relative to transmembrane domain 7. Mutagenesis experiments revealed that the distal and medial phospho-site clusters, but not the proximal, are required for agonist-stimulated ß-arrestin1 or ß-arrestin2 recruitment to CXCR5. Consistent with this, we provide evidence that the distal and medial, but not proximal, phospho-site clusters are required for receptor desensitization. Surprisingly, the individual phospho-site clusters are not required for agonist-stimulated internalization of CXCR5. Further, we show that CXCL13-stimulated CXCR5 internalization and ERK1/2 phosphorylation, but not desensitization, remain intact in HEK293 cells lacking ß-arrestin1 and ß-arrestin2. Our study provides evidence that b-arrestins are recruited to CXCR5 and are required for desensitization but are dispensable for internalization or signaling, suggesting that discrete receptor determinants specify the divergent functions of ß-arrestins. Significance Statement CXCL13 and CXCR5 are important in the immune system and are linked to diseases, yet regulation of CXCR5 signaling remains poorly understood. We provide evidence that a phospho-site cluster located at the extreme distal carboxyl-terminal tail of the receptor is responsible for ß-arrestin recruitment and receptor desensitization. ß-arrestins are not required for CXCL13-stimulated internalization or signaling, indicating that ß-arrestins perform only one of their functions at CXCR5 and that discrete receptor determinants specify the divergent functions of ß-arrestins.

Dual metal-organic-frameworks mediated resonance energy transfer for ultrasensitive electrochemiluminescence immunosensing.

Anelectrochemiluminescence (ECL) biosensor for carcinoembryonic antigen (CEA) based on electrochemiluminescence resonance energy transfer (ECL-RET) was designed. Tris(2,2'-bipyridine)ruthenium(II) (Ru(bpy)32+) was used as an energy donor for ECL-RET, and an Au nanoparticle-modified MOF framework (AuCoFe MOF) was used as an energy receptor for ECL-RET. The ECL emission spectra of Ru(bpy)32+ were in the range 550 to 680nm, and a zinc oxalate MOF encapsulating Ru(bpy)32+ (Ru@ Zn oxalate MOF) was prepared. The UV-vis absorption spectrum of AuCoFe MOF ranges from 280 to 700nm and overlaps with emission spectra of Ru@Zn oxalate MOF, which is critical for RET. The AuCoFe MOF-Ab2 bioconjugate, target CEA antigen, and the Ru@Zn oxalate MOF-Ab1 bioconjugate together form a sandwich structure, resulting in quenching of the ECL signal of Ru@Zn oxalate MOF by AuCoFe MOF. Under the optimized experimental conditions, the ECL-RET sensor exhibited excellent analytical performance in CEA detection with a linear range of 1.0 × 10-13 to 1.0 × 10-8mgmL-1; the minimum limit of detection is 1.4 × 10-14mgmL-1 (S/N = 3); and its recoveries of spiked samples ranging from 99.1 to 100.7%. The developed sensor has excellent stability, reproducibility, and specificity and is suitable for the detection of CEA in human serum and has the potential to provide sensitive detection of other biomarkers of diseases.

Data-driven modeling of subharmonic forced response due to nonlinear resonance

Complex behavior in nonlinear dynamical systems often arises from resonances, which enable intricate energy transfer mechanisms among modes that otherwise would not interact. Theoretical, numerical and experimental methods are available to study such behavior when the resonance arises among modes of the linearized system. Much less understood are, however, resonances arising from nonlinear modal interactions, which cannot be detected from a classical linear analysis. Academic examples of such phenomena have been known, but no systematic method has been developed to detect and model nonlinear resonant interactions purely from numerical or experimental data. Here, we develop such a data-driven methodology that identifies nonlinear resonant response on low-dimensional spectral submanifolds (SSMs) of the dynamical system. Our approach is generally applicable to nonlinear resonances, but we specifically focus here on one particular behavior: subharmonic response in forced nonlinear systems without any resonance among the linearized frequencies of the unforced system. We first illustrate analytically how such a response is born out of a nonlinear resonance hidden in the conservative limit of the system. We then show how this effect can be identified and modeled purely from data. As our main example, we isolate and model previously unexplained response patterns in fluid sloshing experiments.