Energy Transfer Model Research Articles

Comparative analysis of the molecular response characteristics in Platycodon grandiflorus irradiated with heavy ion beams and X-rays

The response of plants to radiation is an essential topic in both space plant cultivation and mutation breeding by radiation. In this study, heavy ion beams (HIB) generated by the ground accelerator and X-rays (XR) were used as models of high linear energy transfer (LET) and low LET radiation to study the molecular response mechanism of Platycodon grandiflorus (P. grandiflorus) seedlings after irradiation. The gene and protein expression profiles of P. grandiflorus after 15 Gy HIB and 20 Gy XR radiation were analyzed by transcriptome and proteome. The results showed that the number of differentially expressed genes (DEGs) induced by HIB radiation was less than that of XR group, but HIB radiation induced more differentially expressed proteins (DEPs). Both HIB and XR radiation activated genes of RNA silencing, double-strand break repair and cell catabolic process. DNA replication and cell cycle related genes were down-regulated. The genes of cell wall and external encapsulating structure were up-regulated after HIB radiation. The gene expression of protein folding and glucan biosynthesis increased after XR radiation. Protein enrichment analysis indicated that HIB radiation resulted in differential protein enriched in photosynthesis and secondary metabolite biosynthesis pathways, while XR radiation induced differential protein of glyoxylate and dicarboxylate metabolism and carbon metabolism. After HIB and XR radiation, the genes of antioxidant system and terpenoid and polyketide metabolic pathways presented different expression patterns. HIB radiation led to the enrichment of non-homologous end-joining pathway. The results will contribute to understanding the biological effects of plants under space radiation.

Stochastic model of collisional energy transfer based on the diffusion equation

Collisional energy transfer from highly excited polyatomic molecules in a heat reservoir is considered as a diffusion process in energy space. It is taken into account that the density of the vibrational states of polyatomic molecules is very high and presented by a continuous energy function. Both the average energy transfer moments per collision and these moments averaged over an ensemble of molecules have been calculated to obtain an exact analytical solution to the diffusion equation. At long times, the solution to the diffusion equation converges to the equilibrium Boltzmann distribution. The conditional probability density decays at long times with a vibrational energy relaxation time. The ensemble averages tend to equilibrium with the same characteristic time.

Unraveling the Missing Link of Bio‐Electrical Stimulation from Body‐Mediated Energy Transfer

AbstractAs the technologies for treating diseases are attracting continuous attention, physical therapy methods, particularly electrical stimulation (ES), have been widely investigated owing to their high effectiveness. As ES essentially requires an external power source, various efforts are being devoted to achieving the application of ES to the human body using nanogenerators. Various studies have verified the effect of ES by applying the same output generated by the device to in vitro and in vivo bio‐electrical stimulation. However, it is unknown whether the electrical output generated by the device can be transmitted equally in the cell unit, and this is considered a common missing link in bio‐electrical stimulation research. Herein, the missing link between electrical devices and in vitro bio‐electrical stimulations is unraveled by the ex vivo, 2D simulation, and in vitro study of body‐mediated energy transfer (BmET) models. In addition, BmET‐based ES is applied to pre‐osteoblasts, and the increased cellular functions are verified.

Plasmon Resonance Energy Transfer Nanoruler for Pinpointing Molecular Distance and Interaction on the Living Cell Membrane.

Developing novel strategies to measure nanoscale distance and molecular interaction on a living cell membrane is of great significance but challenging. Here we develop a model of a linker-free plasmon resonance energy transfer, termed "PRET nanoruler", which is composed of a single-sized nanogold-antibody conjugates donor (G26@antiCD71) and a fluorophore-labeled XQ-2d aptamer receptor (XQ-2d-Cy3), that produces a separation distance (r) dependent energy transfer (ηPRET). Both the theoretical finite element simulation and experiments evidence the observable PRET between single G26NPs and XQ-2d-Cy3. Regardless of the size of ηPRET, we could confirm r is less than 5 nm, the separation of two binding sites is in the range of 13.0-18.0 nm. There is a competitive binding of Tf and XQ-2d-Cy3 on CD71 receptors. PRET nanoruler realizes the estimation of the nanoscale separation distance, and determines the molecular interaction and competitive binding. It is an alternative tool for observing nanoscale single molecular events in the future.

Farm2Fork through the lens of community ecology: concepts and applications in postharvest storage

The environment in which postharvest crops are processed and stored is a dynamic ecosystem influenced not only by environmental factors such as temperature and humidity, but also by biotic influences such as humans and insects. Abiotic influences such as variation in landscapes of warehouses, processing facilities, storage and shipping containers, and urban and agricultural settings can also drive changes in ecosystem processes for insects living in a postharvest system. Principles of community ecology can help to tease apart broad interactions among the environment including succession, interactions with conspecifics that lead to competition and niche partitioning, behavioral ecology variation, and physiology and developmental changes. Focusing on these concepts for integrated pest management (IPM) for stored product insect pests can help pest managers to better predict risk thresholds and develop targeted approaches for treatments. Typically, pest management decisions focus on single species without regards to the interactions with other species. Without consideration of the entire ecosystem, targeted treatments for one species can have both direct and indirect impacts on other species that may have equally detrimental effects on stored products. Current knowledge of stored product ecosystems lags behind what is known for field pest ecosystems, and hinders our ability to design effective control strategies for the whole system. Here, we present a review of work on stored product insect pests using a community ecology lens. We analyze how the current state of the knowledge regarding species interactions and variation and incorporating factors such as movement, species interactions, energy transfer models in succession, behavior, and effects of climate change in ecological modeling can be used to better develop and implement more effective postharvest IPM. Implementing these concepts will significantly improve management of these insects and can help reduce time and cost associated with managing and treating insect infestations.

Analytically Solvable Model for Qubit-Mediated Energy Transfer between Quantum Batteries.

The coherent energy transfer between two identical two-level systems is investigated. Here, the first quantum system plays the role of a charger, while the second can be seen as a quantum battery. Firstly, a direct energy transfer between the two objects is considered and then compared to a transfer mediated by an additional intermediate two-level system. In this latter case, it is possible to distinguish between a two-step process, where the energy is firstly transferred from the charger to the mediator and only after from the mediator to the battery, and a single-step in which the two transfers occurs simultaneously. The differences between these configurations are discussed in the framework of an analytically solvable model completing what recently discussed in literature.

Numerical Simulation of Energy and Mass Transfer in a Magnetic Stirring Photocatalytic Reactor

Hydrogen production via photocatalytic water splitting is one of the promising solutions to energy and environmental issues. Understanding the relationship between hydrogen production in suspended photocatalytic reactions and various influencing factors is crucial for expanding the scale of the system. However, the complexity of physical and chemical factors involved in hydrogen production via photocatalytic water splitting makes systematic research of this technology challenging. In recent research, the simulated light source reactor has become a preferred study object due to its strong controllability. This paper presents a comprehensive energy and mass transfer model for the suspended photocatalytic reaction in a magnetically stirred reactor. The mutual impacts between the flow field, radiation field, and reaction field are analyzed. The simulation results show that the rotating speed of the stirring magneton in the reactor has a significant influence on the flow field. The rotation of the stirring magneton generates a vortex in the central axis area of the reactor, with the relationship between the depth of the vortex f(s) and the rotating speed of the magneton s described as f(s) = 0.27e0.0032s. The distribution of radiation within the reactor is influenced by both the incident radiation intensity and the concentration of the catalyst. The relationship between the penetration depth of radiation g(i) and the incident radiation intensity i is described as g(i) = 10.73ln(i) − 49.59. The relationship between the penetration depth of radiation h(c) and the particle concentration c is given as h(c) = −16.38ln(c) + 15.01. The radiation distribution in the reactor has a substantial impact on hydrogen production, which affects the concentration distribution law of hydrogen. The total amounts of hydrogen generated in the reactor are 1.04 × 10−3 mol and 1.35 × 10−3 mol when the reaction times are 1.0 s and 2.0 s, respectively. This study serves as a foundation for the future scaling of the system and offers theoretical guidance for the optimization of the photocatalytic reactor design and operating conditions.

Bright Fluorophores in the Second Near-Infrared Window: HgSe/CdSe Quantum Dots

Fluorophores emitting in the NIR-IIb wavelength range (1.5-1.7 μm) show great potential for bioimaging due to their large tissue penetration. However, current fluorophores suffer from poor emission with quantum yields ∼2% in aqueous solvents. In this work, we report the synthesis of HgSe/CdSe core/shell quantum dots (QDs) emitting at 1.7 μm through the interband transition. Growth of a thick shell led to a drastic increase in the photoluminescence quantum yield, with a value of 63% in nonpolar solvents. The quantum yields of our QDs and other reported QDs are explained well by a model of Forster resonance energy transfer to ligands and solvent molecules. The model predicts a quantum yield >12% when these HgSe/CdSe QDs are solubilized in water. Our work demonstrates the importance of a thick type-I shell to obtain bright emission in the NIR-IIb region.

Vibration quality evaluation of reinforced concrete using energy transfer model

Vibration is an important step to ensure the compactness of reinforced concrete. In this study, the energy transfer model is firstly proposed based on the working mechanism of the internal vibrator and vibration energy theory to evaluate the vibration quality, and the reliability of the model is verified by the experiment of sinking ball. In addition, the optimal combinations of process parameters are obtained. The worse the fluidity of concrete and the larger the aggregate proportion, the faster the energy attenuation in concrete, but the total energy absorbed by concrete and the energy transfer efficiency of the vibrator increase. The overall efficiency is greater than 57% and the highest average efficiency is 66.1%. The rebar not only accelerates the energy attenuation rate but also reduces the effective energy in the concrete. In the experiments, the average energy consumption rates of rebar are 28.5%, 57.3% and 70.9% with the reinforcement spacing of 20, 10 and 5 cm respectively. The proposed model provides a new method to evaluate the vibration quality, which contributes to dealing with unqualified areas in time and providing reliable process parameters for vibrating construction.

Time-dependent saturation and physics-based nonlinear model of cross-beam energy transfer

The nonlinear physics of cross-beam energy transfer (CBET) for multi-speckled laser beams is examined using large-scale particle-in-cell simulations for a range of laser and plasma conditions relevant to indirect-drive inertial confinement fusion (ICF) experiments. The time-dependent growth and saturation of CBET involve complex, nonlinear ion and electron dynamics, including ion trapping-induced enhancement and detuning, ion acoustic wave (IAW) nonlinearity, oblique forward stimulated Raman scattering (FSRS), and backward stimulated Brillouin scattering (BSBS) in a CBET-amplified seed beam. Ion-trapping-induced detuning of CBET is captured in the kinetic linear response by a new δf-Gaussian-mixture algorithm, enabling an accurate characterization of trapping-induced non-Maxwellian distributions. Ion trapping induces nonlinear processes, such as changes to the IAW dispersion and nonlinearities (e.g., bowing and self-focusing), which, together with pump depletion, FSRS, and BSBS, determine the time-dependent nature and level of CBET gain as the system approaches a steady state. Using VPIC simulations at intensities at and above the onset threshold for ion trapping and the insight from the time-dependent saturation analyses, we construct a nonlinear CBET model from local laser and plasma conditions that predicts the CBET gain and the energy deposition into the plasma. This model is intended to provide a more accurate, physics-based description of CBET saturation over a wide range of conditions encountered in ICF hohlraums compared with linear CBET gain models with ad hoc saturation clamps often used in laser ray-based methods in multi-physics codes.

Ray-based cross-beam energy transfer modeling for broadband lasers

Broadband lasers have the potential to mitigate cross-beam energy transfer (CBET) in direct-drive inertial confinement fusion (ICF) experiments. A quantitative assessment of the bandwidth required for CBET mitigation necessitates the development of broadband ray-based CBET models that can be implemented in the radiation-hydrodynamic codes that are used to design ICF experiments. Two different approaches to broadband ray-based CBET modeling (discrete and fixed spectrum) are developed and compared to wave-based calculations. Both approaches give good agreement with wave-based calculations in ICF-relevant configurations. Full-scale 3D calculations show that the bandwidth required for adequate CBET mitigation increases with increasing scale and drive intensity.

Energy scattering of hybrid FE-SEA model with nonlinear joints

Nonlinearity in structures causes energy scattering between different frequency ranges. This paper proposes a new hybrid FE-SEA formulation to analyse complex structures with nonlinear deterministic components. The formulation is derived in two stages. First the governing equation for deterministic components in time domain is transformed to frequency domain using the method of harmonic balance and the Galerkin method. Equivalent stiffness method is then applied in frequency domain to linearise the nonlinear terms. The second process is regarded to the derivation of the hybrid model. Based on a proposed nonlinear energy transfer model and the linearisation in the first stage, the linearised hybrid FE-SEA governing equation is derived, and the iterative procedure is given. For validation purpose, nonlinear Lagrange–Rayleigh–Ritz method plus Monte Carlo simulation is used as the benchmark model. Two case studies are applied for validation and investigation of the coupling loss factor (CLF). The coupling between subsystems at different frequencies can be reflected by the CLF. Good agreements between the benchmark model and proposed hybrid model can be observed.

Radiative energy transfer model for high frequency vibration of functionally graded beams in thermal environment

A simple and efficient energy flow model is developed by radiative energy transfer method (RETM) to predict the high frequency vibration response of functionally graded(FG) beams in thermal environment. The Timoshenko beam theory is applied to derive the motion governing equations. Thermal effects are incorporated into the dynamic model through the temperature dependent material properties and the thermal stresses. The wavenumber and group velocity associated with thermal stress are included in the energy governing equation. By introducing the artificial springs to simulate different boundary conditions, the energy conversion relationship of the two waves at boundaries are deduced. The response of FG beam loaded by a high-frequency harmonic force is described by energy density and energy flow intensity. They are composed of energy rays from the real source at the load point and energy rays reflected from the imaginary sources at the boundaries. Numerical simulations are performed in various forms of thermal environments to verify the proposed model. The RETM results are compared with those obtained by the wave propagation approach under different parameters, and good consistencies are observed. Numerical results show that the vibrational energy density of FG beams are affected by thermal effects and can be reduced by optimising the gradient factors.

Theoretical investigation of the interaction of ultra-high intensity laser pulses with near critical density plasmas

A theoretical model of energy transfer from laser to particles in the ultra-high intensity regime of laser plasma interaction is proposed, assuming that most of the laser energy will be transferred to hot electrons. Varying the target density and thickness, the optimal parameters for the maximum conversion efficiency of the laser energy to particles are studied. Through 2D particle-in-cell simulations, the model is validated for a near-critical density plasma between (where cm−3 is the critical density for a laser wavelength of m) irradiated by a laser pulse of intensity in the range 1020–1023 W cm−2 and the pulse duration in the range 6.5–100 fs. As an application to this model, laser ion acceleration is studied for a laser intensity of 1022 W cm−2 and a pulse duration of 20 fs. Based on the literature and new findings from our model, the optimum thickness for ion acceleration and the maximum ion energies for an expansion like mechanism are predicted. These results can be used for applications requiring high energy ions and for preparations of experiments at the Apollon and ELI laser facilities.

Unusual Paradigm for DNA-DNA Recognition and Binding: "Socket-Plug" Complementarity.

DNA is the key informational polymer in biology by virtue of its precisely defined self-assembling properties. Watson-Crick complementarity, which underlies DNA's self-assembly, is required not only in biology but has also proved powerful in the field of nanoscience, where it has been utilized to assemble complex 2D and 3D architectures and nanodevices built from the DNA double-helix. Aside from Watson-Crick base-pairing, however, DNA also participates in alternative base pairing schemes, giving rise to DNA triplexes and G-quadruplexes. Herein, we describe "sticky-ended" DNA triplex-quadruplex composites that specifically recognize and bind to each other using a wholly different logic, "socket-plug" complementarity, a shape-sensing fitting of guanine "prongs" into guanine-lacking "cavities." A remarkable property of this kind of complementarity is the key role played in it by specific counter-cations: thus, exclusive "self" socket-plug recognition occurs over "other" in sodium salt solutions while precisely the reverse occurs in potassium salt solutions. We have used gel electrophoresis, Förster resonance energy transfer, alkylation protection, and structural modeling to study this remarkable fundamental property of DNA, that we anticipate will find wide practical application.

Kinetic and thermodynamic compensation phenomena in C3 and C4 energy crops pyrolysis: Implications on reaction mechanisms and product distributions

This work provides insight into possibilities of maximum utilization of C3-C4 energy crops for thermo-chemical conversion (slow pyrolysis) into high value biochemicals, platform chemicals, drop-in fuels and combustible gases, using coupled kinetic and thermodynamic analyses. In order to examine the kinetics of decomposition of lignocellulosic components, model-free and model-based methods faded from thermal analysis data were used. Thermodynamic compensation was used for explicatory of entropy controlled process, where conformational changes and chemical exchange directly affect the type and distribution of obtained pyrolytic products. It was shown that external variable (i.e. the heating rate/temperature) does not change either an entire reaction mechanism (mechanistic nature of MG and AD pyrolyses) or transition state, but it changes activation enthalpy and activation entropy which lead to differences in terms of heat energy consumption, pyrolysis favorability and thus rates of generation of activated complex among feedstocks. To investigate the interplay of catalysts (present in feedstocks as minerals) and reactants, selective energy transfer (SET) model was applied. The model showed an activity of catalyst with different outputs towards two reactants, lignin part of the structure in MG and 1,8-cineole in AD. It was shown that AD is more convenient for thermal conversion than MG, regarding to lower transformation energy requirement, higher reactivity, as well as much faster accumulation of products.

Estimates of prey requirements and initial examination of the primary productivity to support the magellan strait humpback whales

The waters of the Magellan Strait shelter a persistent and small feeding subpopulation of humpback whales (HWs) which is growing at a slower rate than expected, making it highly vulnerable. Despite their low abundance, the HWs represent significant consumers in this austral ecosystem. To better understand the needs of this summering subpopulation in the Magellan Strait feeding area, we estimated the biomass of prey required by HWs to meet their annual energy requirements using a velocity-dependent bioenergetic model and scaled it to two estimates of annual abundance (2011 and 2012), as well as the fraction of primary productivity required (PPR) to support that biomass of prey using a simple trophic energy transfer model. Based on a range of abundance between 75 and 101 whales, the summering subpopulation was estimated to require between 4,007 and 12,673 tons of prey under different population abundances estimates, energy needs, and residence times. These findings imply a minimum and maximum estimate ranging from 12.1 to 62.6 g C/m−2(−|-) y-1, or ∼ 6.8 to 41.5 % of net primary productivity in the feeding area to sustain the prey species directly required by HWs. Even though our estimates of prey requirements and PPR may change as new and better data become available, the results show that this small summering subpopulation requires at least a significant portion of annual phytoplankton production.

Recent progresses on ion beam irradiation induced structure and performance modulation of two-dimensional materials.

Two-dimensional (2D) materials are receiving significant attention for both fundamental research and industrial applications due to their unparalleled properties and wide application potential. In this case, the controllable modulation of their structures and properties is essential for the realization and further expansion of their applications. Accordingly, ion beam irradiation techniques, with large scope to adjust parameters, high manufacturing resolution, and a series of advanced equipment being developed, have been demonstrated to have obvious advantages in manipulating the structure and performance of 2D materials. In recent years, many research efforts have been devoted to uncovering the underlying mechanism and control rules regarding ion irradiation induced phenomena in 2D materials, aiming at fulfilling their application potential as soon as possible. Herein, we review the research progress in the interaction between energetic ions and 2D materials based on the energy transfer model, type of ion source, structural modulation, performance modification of 2D materials, and then their application status, aiming to provide useful information for researchers in this field and stimulating more research advances.

Surface hopping modeling of charge and energy transfer in active environments.

An active environment is any atomic or molecular system changing a chromophore's nonadiabatic dynamics compared to the isolated molecule. The action of the environment on the chromophore occurs by changing the potential energy landscape and triggering new energy and charge flows unavailable in the vacuum. Surface hopping is a mixed quantum-classical approach whose extreme flexibility has made it the primary platform for implementing novel methodologies to investigate the nonadiabatic dynamics of a chromophore in active environments. This Perspective paper surveys the latest developments in the field, focusing on charge and energy transfer processes.

Understanding the mechanism of the energy transfer process from non-plasmonic fluorescence bimetallic nanoparticles to plasmonic gold nanoparticles.

Understanding the fundamentals behind the photophysical response of a fluorescing species in the vicinity of plasmonic nanoparticles is of great interest due to the importance of this event in various applications. The present work has been carried out to throw light on how plasmonic nanoparticles electronically interact with non-plasmonic nanoparticles. Specifically, in this work, the excitation energy transfer (EET) from fluorescence bimetallic silver capped gold (F-AgAu) to gold nanoparticles (AuNPs) and how this process can be modulated by cetyltrimethylammonium bromide (CTAB) have been investigated at both ensemble average and single particle levels. Steady-state and time-resolved fluorescence studies have revealed that the fluorescence intensity and lifetime of F-AgAu in the presence of AuNPs are significantly quenched. Cyclic voltammetry (CV) and polarity-dependent studies have ruled out the possibility of an electron transfer mechanism. The increased non-radiative decay rate has substantiated that the photoluminescence quenching is due to excitation energy transfer from F-AgAu to AuNPs. Interestingly, investigations have revealed that the energy transfer efficiency is reduced from 87% to 28% in the presence of CTAB due to the formation of a CTAB bilayer over AuNPs. Analysis of the data by conventional EET, nano surface energy transfer (NSET), and stretched exponential models have firmly established that the EET process follows a 1/d4 distance dependence (NSET) rather than conventional 1/d6 distance dependence as predicted with the Förster resonance energy transfer model. Additionally, single particle level measurements through fluorescence lifetime imaging microscopy (FLIM) studies have clearly demonstrated that the surfactant (CTAB) can play an important role in controlling the EET process from non-plasmonic to plasmonic nanoparticles. The outcome of the present EET between two different classes of nanoparticles is expected to be useful in developing nanoscale systems for various optoelectronic applications.