Recent worldwide foodborne outbreaks emphasize the need for the development of rapid and accurate method for pathogen detection. To address such issues, a new colony based label-free detection method working on the pr...Recent worldwide foodborne outbreaks emphasize the need for the development of rapid and accurate method for pathogen detection. To address such issues, a new colony based label-free detection method working on the principles of elastic light scattering was introduced. In order to build libraries of scattering images for bacterial pathogens, it is pertinent to determine the effect of preparation and storage of the agar media on the scatter patterns. Scatter patterns of three Escherichia coli serovars (O26, O111 and O157) were studied and used in a model system, after growth on Sorbitol-MacConkey agar plates that were prepared and stored at different conditions in the laboratory. Quantitative image processing software was used to analyze variation in scatter patterns of the same serovar on media prepared under various standard laboratory conditions and to generate a cross-validation matrix for comparison. Based on the results, it was determined that attention should be given during preparation of media so that the agar plates are not air-dried more than 10 - 20 min after solidification at room temperature. The plates could be stored in sealed bags in cold room (4oC - 10oC) for up to a month before use. The findings of this study should provide guidelines in preparation, storage, and handling of media for generation of reproducible scatter patterns of bacterial colonies with the light scattering sensor for pathogen detection.展开更多
Harmful algal blooms (HABs), caused by the overgrowth of certain phytoplankton species, have negative effects on marine environments and coastal fisheries. In addition to cell-counting methods using phytoplankton nets...Harmful algal blooms (HABs), caused by the overgrowth of certain phytoplankton species, have negative effects on marine environments and coastal fisheries. In addition to cell-counting methods using phytoplankton nets, a hydroacoustic technique based on acoustic backscattering has been proposed for the detection of phytoplankton blooms. However, little is known of the acoustic properties of HAB species. In this study, as essential data to support this technique, we measured the acoustic properties of two HAB species, Akashiwo sanguinea and Alexandrium affine, which occur in the South Sea off the coast of Korea. Due to the small size of the target, we used ultrasound for the measurements. Experiments were conducted under laboratory and field conditions. In the laboratory experiment, the acoustic signal received from each species was directly proportional to the cell abundance. We derived a relationship between the cell abundance and acoustic signal received for each species. The measured signals were compared to predictions of a fluid sphere scattering model. When A. sanguinea blooms appeared at an abundance greater than 3 500 cells/mL, the acoustic signals varied with cell abundance, showing a good correlation. These results confirm that acoustic measurements can be used to detect HAB species.展开更多
The results of comprehensive microscopic optical model calculations are pres-ented for the K<sup>+</sup> scattering from <sup>6</sup>Li,<sup>12</sup>C,<sup>28</sup>Si an...The results of comprehensive microscopic optical model calculations are pres-ented for the K<sup>+</sup> scattering from <sup>6</sup>Li,<sup>12</sup>C,<sup>28</sup>Si and <sup>40</sup>Ca at incident momenta 400-800MeV/c.The unconventional medium effect （i.e.the density-dependent correction forthe K<sup>+</sup>-nucleon scattering amplitude） is considered in two approaches.Both results arein agreement with recent experimental data.The influence of the correction on K<sup>+</sup> scat-tering from different nuclei are discussed in detail and only a weak dependence of thein-medium nucleon“swelling”effects on the mass number of target nuclei is found ex-cept for very light loosely-bound nucleus.展开更多
The present study deals with the scattering of oblique surface water waves by small undulation on the bottom in the presence of a thin vertical barrier. Here, three different configurations of vertical barriers are in...The present study deals with the scattering of oblique surface water waves by small undulation on the bottom in the presence of a thin vertical barrier. Here, three different configurations of vertical barriers are investigated. Perturbation analysis is employed to determine the physical quantities, namely, the reflection and transmission coefficients. In this analysis, many different Boundary Value Problems (BVPs) are obtained out of which the first two bvps are considered. The zeroth order bvp is solved with the aid of eigenfunction expansion method. The first order reflection and transmission coefficients are derived in terms of the integrals by the method of the Green's integral theorem. The variation of these coefficients is plotted and analyzed for different physical parameters. Furthermore, the energy balance relation, an important relation in the study of water wave scattering, is derived and checked for assuring the correctness of the numerical results for the present problem.展开更多
Two assumptions are typically made when radar echo signals from precipitation are analyzed to determine the micro-physical parameters of raindrops:(1) the raindrops are assumed to be spherical;(2) multiple scattering ...Two assumptions are typically made when radar echo signals from precipitation are analyzed to determine the micro-physical parameters of raindrops:(1) the raindrops are assumed to be spherical;(2) multiple scattering effects are ignored. Radar cross sections(RCS) are usually calculated using Rayleigh's scattering equation with the simple addition method in the radar meteorological equation.We investigate the extent to which consideration of the effects of multiple scattering and of the non-spherical shapes within actual raindrop swarms would result in RCS values significantly different from those obtained by conventional analytical methods. First, we establish spherical and non-spherical raindrop models, with Gamma, JD, JT, and MP size distributions, respectively. We then use XFDTD software to calculate the radar cross sections of the above raindrop models at the S, C, X and Ku radar bands. Our XFDTD results are then compared to RCS values calculated by the Rayleigh approximation with simple addition methods. We find that:(1) RCS values calculated using multiple scattering XFDTD software differ significantly from those calculated by the simple addition method at the same band for the same model. In particular, for the spherical raindrop models, the relative differences in RCS values between the methods range from a maximum of 89.649% to a minimum of 43.701%; for the non-spherical raindrop models, the relative differences range from a maximum of 85.868% to a minimum of 11.875%.(2) Our multiple scattering XFDTD results, compared to those obtained from the Rayleigh formula,again differ at all four size distributions, by relative errors of 169.522%, 37.176%, 216.455%, and 63.428%, respectively. When nonspherical effects are considered, differences in RCS values between our XFDTD calculations and Rayleigh calculations are smaller; at the above four size distributions the relative errors are 0.213%, 0.171%, 7.683%, and 44.514%, respectively. RCS values computed by considering multiple scattering and non-spherical particle shapes are larger than Rayleigh RCS results, at all of the above four size distributions; the relative errors between the two methods are 220.673%, 129.320%, 387.240%, and 186.613%, respectively. After changing the arrangement of particles at four size distributions in the case of multiple scattering effect and non-spherical effect, the RCS values of Arrangement 2 are smaller than those of Arrangement 1; the relative errors for Arrangement 2, compared to Rayleigh, are 60.558%, 76.263%, 85.941%,64.852%, respectively. We have demonstrated that multiple scattering, non-spherical particle shapes, and the arrangement within particle swarms all affect the calculation of RCS values. The largest influence appears to be that of the multiple scattering effect.Consideration of particle shapes appears to have the least influence on computed RCS values. We conclude that multiple scattering effects must be considered in practical meteorological detection.展开更多
The mechanisms of enhancing spin-orbit torque(SOT) have attracted significant attention, particularly regarding the influence of extrinsic scattering mechanisms on SOT efficiency, as they complement intrinsic contribu...The mechanisms of enhancing spin-orbit torque(SOT) have attracted significant attention, particularly regarding the influence of extrinsic scattering mechanisms on SOT efficiency, as they complement intrinsic contributions. In multilayer systems, extrinsic interfacial scattering, along with scattering from defects or impurities inside the materials, plays a crucial role in affecting the SOT efficiency. In this study, we successfully fabricated high-quality epitaxially grown [Ir/Pt]N superlattices with an increasing number of interfaces using a magnetron sputtering system to investigate the contribution of extrinsic interfacial scattering to SOT efficiency. We measured SOT efficiency through spin-torque ferromagnetic resonance methods and determined the spin Hall angle using the spin pumping technique. Additionally, we calculated spin transparency based on the SOT efficiency and spin Hall angle. Our findings indicate that the values of SOT efficiency, spin Hall angle, and spin transparency are enhanced in the superlattice structure compared to Pt, which we attribute to the increase in interfacial scattering.This research offers an effective strategy for designing and fabricating advanced spintronic devices.展开更多
By employing a full quantum theory of electron-photon scattering in intense laser fields,we calculate the angularresolved radiation rate of the fundamental wave in Thomson scattering.We investigate the dependence of r...By employing a full quantum theory of electron-photon scattering in intense laser fields,we calculate the angularresolved radiation rate of the fundamental wave in Thomson scattering.We investigate the dependence of radiation rate on Euler angles and elucidate the underlying physical mechanism.The figure-8 profile of the radiation rate within the polarization plane is validated,while its evolution with respect to laser intensity and electron momentum is illustrated.Our findings reveal that in lower-intensity laser fields and for slow electron motion,the angular-resolved radiation rate exhibits distinct dipole emission characteristics.However,significant changes are observed at high laser intensities and/or large electron momenta,leading to pronounced alterations in the angular-resolved radiation rate.Remarkably similar variation patterns can be achieved by proportionally adjusting both laser intensity and electron momentum.展开更多
Deep learning methods have achieved significant progress in solving partial differential equations.However,when applied to the widely used anisotropic scattering neutron transport equations in reactor engineering,thes...Deep learning methods have achieved significant progress in solving partial differential equations.However,when applied to the widely used anisotropic scattering neutron transport equations in reactor engineering,these encounter significant challenges.To address this issue,this study introduces a multi-antiderivative transformation alternating iterative deep learning method(M-AIM).This method transforms the integral terms of the scattering and fission sources in the transport equation into multiple antiderivative functions corresponding to the integrand,converts the differential-integral form of the transport equation into an exact differential equation,and establishes the necessary constraints for a unique solution.The M-AIM uses multiple deep neural networks to map the unknown angular flux density of transport equations and represents various forms of antiderivative functions.It constructs the corresponding weighted loss functions.By alternating iterative training with deep learning methods applied to these neural networks,the loss is reduced gradually.When the loss decreases to a preset minimum,the neural network approaches a numerical solution for both angular flux density and antiderivative functions.This paper presents a numerical verification of geometries such as flat plates and spheres.It verifies the validity of the theoretical framework and associated methods.The study contributes to the development of novel technical approaches for applying deep learning to solve anisotropic scattering neutron transport equations in reactor engineering.展开更多
The quasi-monochromatic,continuously energy-tunable,and high-brightness gamma rays that are produced by an inverse Compton scattering(ICS)light source provide an ideal probe for gamma-ray imaging.However,owing to the ...The quasi-monochromatic,continuously energy-tunable,and high-brightness gamma rays that are produced by an inverse Compton scattering(ICS)light source provide an ideal probe for gamma-ray imaging.However,owing to the influence of the intrinsic energy-angle correlation spectrum of this type of light source,monochromatic computed tomography(CT),especially in the gamma-ray energy region,can only be realized in a low-efficiency manner,similar to first-generation CT.A dual-energy scan scheme with a large imaging field of view(FOV)was developed in this study to improve the imaging efficiency.The effectiveness of this scheme was demonstrated based on the beam parameters of a typical ICS light source using Monte Carlo simulations.By leveraging the principle of basis material decomposition,the influence of the energyangle correlation spectrum on CT reconstruction was corrected,and a monochromatic CT image of the imaging object was accurately reconstructed.Furthermore,the electron density and effective atomic number of the imaging object could be obtained simultaneously.展开更多
Stimulated Raman scattering(SRS)under a new ignition path that combines the advantages of direct-drive(DD)and indirect-drive(ID)schemes is investigated experimentally at the Shenguang-100 kJ facility.The results show ...Stimulated Raman scattering(SRS)under a new ignition path that combines the advantages of direct-drive(DD)and indirect-drive(ID)schemes is investigated experimentally at the Shenguang-100 kJ facility.The results show that collective SRS in the plasma produced by ablating a polyimide film is detected for the ID beams,but is suppressed by adding a toe before the main pulse of the ID beams.The toe also strongly influences SRS of both the ID and DD beams excited in the plasma generated in the hohlraum.When a toe is used,the SRS spectra of the DD beams show that SRS tends to be excited in lower plasma density,which will result in a lower risk of super-hot electrons.Measurements of hot electrons support this conclusion.This research will help us produce a better pulse design for this new ignition path.展开更多
A scheme based on irregular V-shaped silicon nanoantennas is proposed to optimize transverse unidirectional scattering under plane wave irradiation.Traditional methods of designing regular shapes offer fewer parameter...A scheme based on irregular V-shaped silicon nanoantennas is proposed to optimize transverse unidirectional scattering under plane wave irradiation.Traditional methods of designing regular shapes offer fewer parameters and higher search efficiency.However,due to the limitations of regular shapes,it is challenging to meet high-precision design requirements.Irregular shape design allows for a broader range of adjustments,but the complexity of shape parameters leads to lower search efficiency and a higher likelihood of converging to local optima.展开更多
Recent experiments at the National Ignition Facility and theoretical modeling suggest that side stimulated Raman scattering(SSRS)instability could reduce laser–plasma coupling and generate considerable fluxes of supr...Recent experiments at the National Ignition Facility and theoretical modeling suggest that side stimulated Raman scattering(SSRS)instability could reduce laser–plasma coupling and generate considerable fluxes of suprathermal hot electrons under interaction conditions envisaged for direct-drive schemes for inertial confinement fusion.Nonetheless,SSRS remains to date one of the least understood parametric instabilities.Here,we report the first angularly and spectrally resolved measurements of scattered light at laser intensities relevant for the shock ignition scheme(I×10^(16)W/cm^(2)),showing significant SSRS growth in the direction perpendicular to the laser polarization.Modification of the focal spot shape and orientation,obtained by using two different random phase plates,and of the density gradient of the plasma,by utilizing exploding foil targets of different thicknesses,clearly reveals a different dependence of backward SRS(BSRS)and SSRS on experimental parameters.While convective BSRS scales with plasma density scale length,as expected by linear theory,the growth of SSRS depends on the spot extension in the direction perpendicular to laser polarization.Our analysis therefore demonstrates that under current experimental conditions,with density scale lengths L_(n)≈60–120μm and spot sizes FWHM≈40–100μm,SSRS is limited by laser beam size rather than by the density scale length of the plasma.展开更多
The problem of water wave scattering by a thin vertical elastic plate submerged in uniform finite depth water is investigated here.The boundary condition on the elastic plate is derived from the Bernoulli-Euler equati...The problem of water wave scattering by a thin vertical elastic plate submerged in uniform finite depth water is investigated here.The boundary condition on the elastic plate is derived from the Bernoulli-Euler equation of motion satisfied by the plate.Using the Green’s function technique,from this boundary condition,the normal velocity of the plate is expressed in terms of the difference between the velocity potentials(unknown)across the plate.The two ends of the plate are either clamped or free.The reflection and transmission coefficients are obtained in terms of the integrals’involving combinations of the unknown velocity potential on the two sides of the plate,which satisfy three simultaneous integral equations and are solved numerically.These coefficients are computed numerically for various values of different parameters and depicted graphically against the wave number in a number of figures.展开更多
The ability to precisely estimate the void fraction of multiphase flow in a pipe is very important in the petroleum industry. In this paper, an approach based on our previous works is proposed for predicting the void ...The ability to precisely estimate the void fraction of multiphase flow in a pipe is very important in the petroleum industry. In this paper, an approach based on our previous works is proposed for predicting the void fraction independent of flow regime and liquid phase density changes in gas–liquid two-phase flows. Implemented technique is a combination of dual modality densitometry and multi-beam gamma-ray attenuation techniques. The detection system is comprised of a single energy fan beam,two transmission detectors, and one scattering detector. In this work, artificial neural network(ANN) was also implemented to predict the void fraction percentage independent of the flow regime and liquid phase density changes. Registered counts in three detectors and void fraction percentage were utilized as the inputs and output of ANN, respectively. By applying the proposed methodology, the void fraction was estimated with a mean relative error of less than just 1.2480%.展开更多
In this paper, Method of Kobayashi Potential is used to determine the scattering behavior of a strip which is placed at the air-complex conjugate medium interface. And discussion is presented that how the complex conj...In this paper, Method of Kobayashi Potential is used to determine the scattering behavior of a strip which is placed at the air-complex conjugate medium interface. And discussion is presented that how the complex conjugate medium mod-ify the scattering properties of the strip. A comparison is also given with that if we replace the conjugate medium with standard dielectric medium. E-polarized electromagnetic plane wave is supposed to be obliquely incident upon the ge-ometry. Scattered fields in both the half spaces are supposed in terms of unknown weighting functions. Discontinuous properties of Weber-Schafheitlin integral and orthogonal properties of Jacobi’s polynomials are used to determine these unknown weighting functions. Far scattered fields have been calculated using Saddle Point Method and computed for different parameters of interest.展开更多
In neutron and photon transport problems,anisotropic scattering is of great importance for the particle flux,especially when the angular flux has a strong forward peak in shielding analyses.The conventional Legendre e...In neutron and photon transport problems,anisotropic scattering is of great importance for the particle flux,especially when the angular flux has a strong forward peak in shielding analyses.The conventional Legendre expansion is widely used in discrete ordinates transport codes because of algebraic simplifications with spherical harmonics for the scattering source.However,negative cross sections caused by the finitely truncated expansion may give rise to a negative source and flux.A simple method is adopted,based on integrating functions of scattering moments,to evaluate anisotropy and convergence of expanded functions.A series of problems were designed with angular fluxes of different anisotropy,and numerical simulations were performed using the ARES transport code to study different treatments and algorithms for scattering.Results show that the diagonal transport approximation is more stable and obtains a similar accuracy with the extended approximation.A conservative fixup for the negative source could ensure particle balance and improve computational accuracy significantly for photon transport.The effect of anisotropic scattering is problem-dependent,and no distinct differences among various methods are observed for volume source problems with a continuous energy source.For beam source problems,flux results are sensitive to negative scattering functions,and strictly nonnegative cross sections need to be implemented.展开更多
The correspondence principle and the condition of supplementation were introduced by N. Bohr for the sub-mission of light phenomena, taking into account the wave nature of electromagnetic radiation on one hand, and it...The correspondence principle and the condition of supplementation were introduced by N. Bohr for the sub-mission of light phenomena, taking into account the wave nature of electromagnetic radiation on one hand, and its quantum structures on the other. In this paper, correspondence principle combines two models of matter, namely, the classical point of view of environment can be considered as an ensemble no equally-frequencies oscillators, i.e. electrons in the surrounding various atoms (molecules) of the matter and characterized by its own set of frequencies (but not hesitant in the absence of an energy source) and the quantum - environment could be presented as a set (ensemble) two-level systems, a wide range of Bohr fre-quencies. According to the correspondence principle Bohr jump-frequencies of atoms (molecules or nano particles) and natural frequencies oscillations of electrons of the same environment - oscillators are equal to each other. The dispersion characteristics of the environment in the every study range of optical frequencies correspond to the model of the classical harmonic oscillator of Lorenz, capable oscillates with Bohr fre-quency. Using the laws of classical mechanics to describe the environment and its dispersion properties, and the simultaneous presentation of light radiation in the form of a beam interacting with the environment of photons (quanta, corpuscles) helps explain peculiarities of the spectral composition Raleigh light scattered.展开更多
Muon scattering tomography(MST) is a powerful noninvasive imaging technique with significant applications in nuclear material detection and security screening.Traditional MST usually relies on the point of closest app...Muon scattering tomography(MST) is a powerful noninvasive imaging technique with significant applications in nuclear material detection and security screening.Traditional MST usually relies on the point of closest approach(PoCA) algorithm to reconstruct images from muon scattering data;however,PoCA often suffers from suboptimal image clarity and resolution.To overcome these challenges,we propose a novel approach that leverages reinforcement learning(RL) to enhance MST reconstruction,termed the μRL-enhanced method.By framing the MST optimization task as an RL problem,we developed an intelligent agent capable of dynamically adjusting the key PoCA parameters.The agent is trained using a multi-objective reward function that guides the optimization toward higher-quality reconstructions.Our experimental results show that theμRL-enhanced method significantly outperforms the traditional PoCA baseline acros s multiple benchmark metrics.Specifically,the proposed approach on average attains a 307% improvement in the intersection over union(IoU),a 79% increase in the structural similarity index measure(SSIM),and a 8.4% enhancement in the peak signal-to-noise ratio(PSNR) across four experiments.Furthermore,when benchmarked against the maximum likelihood scattering and displacement(MLSD)algorithm,the μRL-enhanced method offers modest gains in PS NR and IoU,together with a one-third increase in SSIM.These improvements demonstrate the enhanced reconstruction accuracy and structural fidelity of the μRL-enhanced method,highlighting its potential to advance MST technologies and their applications.展开更多
In complex media scattering,multiple scattering severely degrades the optical wavefront and results in blurred images,while the spectral distortion caused by the scattering effect leads to severe color distortion.Achi...In complex media scattering,multiple scattering severely degrades the optical wavefront and results in blurred images,while the spectral distortion caused by the scattering effect leads to severe color distortion.Achieving color high-resolution imaging through scattering media remains a significant challenge.Here,we propose a broadband,polarization-based method for color high-resolution imaging through scattering media.This approach enables high-resolution reconstruction by effectively separating the speckle illumination pattern from the mixed-scattering field information,leveraging polarization common-mode characteristics.Concurrently,it incorporates chromatic balance compensation to correct spectral aliasing in the scattered light field,enabling color high-resolution imaging through complex scattering media.To further optimize color distortion caused by scattering,a compensation strategy combining color constancy and white balance theory is adopted.Experimental results demonstrate that the proposed method significantly enhances both spatial resolution and color fidelity across various scattering conditions and target materials,showcasing strong adaptability and robustness.This approach provides an effective solution for achieving high-resolution color optical imaging in complex scattering environments.展开更多
Small angle x-ray scattering(SAXS)is an advanced technique for characterizing the particle size distribution(PSD)of nanoparticles.However,the ill-posed nature of inverse problems in SAXS data analysis often reduces th...Small angle x-ray scattering(SAXS)is an advanced technique for characterizing the particle size distribution(PSD)of nanoparticles.However,the ill-posed nature of inverse problems in SAXS data analysis often reduces the accuracy of conventional methods.This article proposes a user-friendly software for PSD analysis,GranuSAS,which employs an algorithm that integrates truncated singular value decomposition(TSVD)with the Chahine method.This approach employs TSVD for data preprocessing,generating a set of initial solutions with noise suppression.A high-quality initial solution is subsequently selected via the L-curve method.This selected candidate solution is then iteratively refined by the Chahine algorithm,enforcing constraints such as non-negativity and improving physical interpretability.Most importantly,GranuSAS employs a parallel architecture that simultaneously yields inversion results from multiple shape models and,by evaluating the accuracy of each model's reconstructed scattering curve,offers a suggestion for model selection in material systems.To systematically validate the accuracy and efficiency of the software,verification was performed using both simulated and experimental datasets.The results demonstrate that the proposed software delivers both satisfactory accuracy and reliable computational efficiency.It provides an easy-to-use and reliable tool for researchers in materials science,helping them fully exploit the potential of SAXS in nanoparticle characterization.展开更多
文摘Recent worldwide foodborne outbreaks emphasize the need for the development of rapid and accurate method for pathogen detection. To address such issues, a new colony based label-free detection method working on the principles of elastic light scattering was introduced. In order to build libraries of scattering images for bacterial pathogens, it is pertinent to determine the effect of preparation and storage of the agar media on the scatter patterns. Scatter patterns of three Escherichia coli serovars (O26, O111 and O157) were studied and used in a model system, after growth on Sorbitol-MacConkey agar plates that were prepared and stored at different conditions in the laboratory. Quantitative image processing software was used to analyze variation in scatter patterns of the same serovar on media prepared under various standard laboratory conditions and to generate a cross-validation matrix for comparison. Based on the results, it was determined that attention should be given during preparation of media so that the agar plates are not air-dried more than 10 - 20 min after solidification at room temperature. The plates could be stored in sealed bags in cold room (4oC - 10oC) for up to a month before use. The findings of this study should provide guidelines in preparation, storage, and handling of media for generation of reproducible scatter patterns of bacterial colonies with the light scattering sensor for pathogen detection.
基金project titled "Establishment and demonstration of red tide detection and prediction system for minimizing red tide damage" funded by the Ministry of Oceans and Fisheries, Korea (PM61410)
文摘Harmful algal blooms (HABs), caused by the overgrowth of certain phytoplankton species, have negative effects on marine environments and coastal fisheries. In addition to cell-counting methods using phytoplankton nets, a hydroacoustic technique based on acoustic backscattering has been proposed for the detection of phytoplankton blooms. However, little is known of the acoustic properties of HAB species. In this study, as essential data to support this technique, we measured the acoustic properties of two HAB species, Akashiwo sanguinea and Alexandrium affine, which occur in the South Sea off the coast of Korea. Due to the small size of the target, we used ultrasound for the measurements. Experiments were conducted under laboratory and field conditions. In the laboratory experiment, the acoustic signal received from each species was directly proportional to the cell abundance. We derived a relationship between the cell abundance and acoustic signal received for each species. The measured signals were compared to predictions of a fluid sphere scattering model. When A. sanguinea blooms appeared at an abundance greater than 3 500 cells/mL, the acoustic signals varied with cell abundance, showing a good correlation. These results confirm that acoustic measurements can be used to detect HAB species.
基金The project supportcd in part by the National Natural Science Foundation of China
文摘The results of comprehensive microscopic optical model calculations are pres-ented for the K<sup>+</sup> scattering from <sup>6</sup>Li,<sup>12</sup>C,<sup>28</sup>Si and <sup>40</sup>Ca at incident momenta 400-800MeV/c.The unconventional medium effect （i.e.the density-dependent correction forthe K<sup>+</sup>-nucleon scattering amplitude） is considered in two approaches.Both results arein agreement with recent experimental data.The influence of the correction on K<sup>+</sup> scat-tering from different nuclei are discussed in detail and only a weak dependence of thein-medium nucleon“swelling”effects on the mass number of target nuclei is found ex-cept for very light loosely-bound nucleus.
基金Supported by SERB-DST Grant(No.SB/FTP/MS-034/2013)
文摘The present study deals with the scattering of oblique surface water waves by small undulation on the bottom in the presence of a thin vertical barrier. Here, three different configurations of vertical barriers are investigated. Perturbation analysis is employed to determine the physical quantities, namely, the reflection and transmission coefficients. In this analysis, many different Boundary Value Problems (BVPs) are obtained out of which the first two bvps are considered. The zeroth order bvp is solved with the aid of eigenfunction expansion method. The first order reflection and transmission coefficients are derived in terms of the integrals by the method of the Green's integral theorem. The variation of these coefficients is plotted and analyzed for different physical parameters. Furthermore, the energy balance relation, an important relation in the study of water wave scattering, is derived and checked for assuring the correctness of the numerical results for the present problem.
基金supported by the Natural Science Foundation of Jiangsu Province (Grant No. BK20170945)the National Natural Science Foundation of China (Grant Nos. 41675029+6 种基金 41275004 61372066 41571348)National Key Laboratory of Disaster Weather, China Academy of Meteorological Sciences (2016LASW-B12)the Key Laboratory for Aerosol-Cloud-Precipitation of CMA-NUIST (KDW1703)the Startup Foundation for Introducing Talent of Nanjing University of Information Science and Technology (2016r028)Earth Science Virtual Simulation Experiment Teaching Course Construction Project of Nanjing University of Information Science and Technology (XNFZ2017C02)
文摘Two assumptions are typically made when radar echo signals from precipitation are analyzed to determine the micro-physical parameters of raindrops:(1) the raindrops are assumed to be spherical;(2) multiple scattering effects are ignored. Radar cross sections(RCS) are usually calculated using Rayleigh's scattering equation with the simple addition method in the radar meteorological equation.We investigate the extent to which consideration of the effects of multiple scattering and of the non-spherical shapes within actual raindrop swarms would result in RCS values significantly different from those obtained by conventional analytical methods. First, we establish spherical and non-spherical raindrop models, with Gamma, JD, JT, and MP size distributions, respectively. We then use XFDTD software to calculate the radar cross sections of the above raindrop models at the S, C, X and Ku radar bands. Our XFDTD results are then compared to RCS values calculated by the Rayleigh approximation with simple addition methods. We find that:(1) RCS values calculated using multiple scattering XFDTD software differ significantly from those calculated by the simple addition method at the same band for the same model. In particular, for the spherical raindrop models, the relative differences in RCS values between the methods range from a maximum of 89.649% to a minimum of 43.701%; for the non-spherical raindrop models, the relative differences range from a maximum of 85.868% to a minimum of 11.875%.(2) Our multiple scattering XFDTD results, compared to those obtained from the Rayleigh formula,again differ at all four size distributions, by relative errors of 169.522%, 37.176%, 216.455%, and 63.428%, respectively. When nonspherical effects are considered, differences in RCS values between our XFDTD calculations and Rayleigh calculations are smaller; at the above four size distributions the relative errors are 0.213%, 0.171%, 7.683%, and 44.514%, respectively. RCS values computed by considering multiple scattering and non-spherical particle shapes are larger than Rayleigh RCS results, at all of the above four size distributions; the relative errors between the two methods are 220.673%, 129.320%, 387.240%, and 186.613%, respectively. After changing the arrangement of particles at four size distributions in the case of multiple scattering effect and non-spherical effect, the RCS values of Arrangement 2 are smaller than those of Arrangement 1; the relative errors for Arrangement 2, compared to Rayleigh, are 60.558%, 76.263%, 85.941%,64.852%, respectively. We have demonstrated that multiple scattering, non-spherical particle shapes, and the arrangement within particle swarms all affect the calculation of RCS values. The largest influence appears to be that of the multiple scattering effect.Consideration of particle shapes appears to have the least influence on computed RCS values. We conclude that multiple scattering effects must be considered in practical meteorological detection.
基金financially supported by the Science Center of the National Science Foundation of China (Grant No. 52088101)the National Natural Science Foundation of China (Grant Nos. 52161160334, 12274437, 12174426, and 52271237)+1 种基金the Chinese Academy of Sciences (CAS) Project for Young Scientists in Basic Research No. YSBR-084the CAS Youth Interdisciplinary Team。
文摘The mechanisms of enhancing spin-orbit torque(SOT) have attracted significant attention, particularly regarding the influence of extrinsic scattering mechanisms on SOT efficiency, as they complement intrinsic contributions. In multilayer systems, extrinsic interfacial scattering, along with scattering from defects or impurities inside the materials, plays a crucial role in affecting the SOT efficiency. In this study, we successfully fabricated high-quality epitaxially grown [Ir/Pt]N superlattices with an increasing number of interfaces using a magnetron sputtering system to investigate the contribution of extrinsic interfacial scattering to SOT efficiency. We measured SOT efficiency through spin-torque ferromagnetic resonance methods and determined the spin Hall angle using the spin pumping technique. Additionally, we calculated spin transparency based on the SOT efficiency and spin Hall angle. Our findings indicate that the values of SOT efficiency, spin Hall angle, and spin transparency are enhanced in the superlattice structure compared to Pt, which we attribute to the increase in interfacial scattering.This research offers an effective strategy for designing and fabricating advanced spintronic devices.
基金Project supported by the National Natural Science Foundation of China(Grant No.12074261)the Natural Science Foundation of Shanghai(Grant No.20ZR1441600)。
文摘By employing a full quantum theory of electron-photon scattering in intense laser fields,we calculate the angularresolved radiation rate of the fundamental wave in Thomson scattering.We investigate the dependence of radiation rate on Euler angles and elucidate the underlying physical mechanism.The figure-8 profile of the radiation rate within the polarization plane is validated,while its evolution with respect to laser intensity and electron momentum is illustrated.Our findings reveal that in lower-intensity laser fields and for slow electron motion,the angular-resolved radiation rate exhibits distinct dipole emission characteristics.However,significant changes are observed at high laser intensities and/or large electron momenta,leading to pronounced alterations in the angular-resolved radiation rate.Remarkably similar variation patterns can be achieved by proportionally adjusting both laser intensity and electron momentum.
基金supported by the National Natural Science Foundation of China(No.12575189)。
文摘Deep learning methods have achieved significant progress in solving partial differential equations.However,when applied to the widely used anisotropic scattering neutron transport equations in reactor engineering,these encounter significant challenges.To address this issue,this study introduces a multi-antiderivative transformation alternating iterative deep learning method(M-AIM).This method transforms the integral terms of the scattering and fission sources in the transport equation into multiple antiderivative functions corresponding to the integrand,converts the differential-integral form of the transport equation into an exact differential equation,and establishes the necessary constraints for a unique solution.The M-AIM uses multiple deep neural networks to map the unknown angular flux density of transport equations and represents various forms of antiderivative functions.It constructs the corresponding weighted loss functions.By alternating iterative training with deep learning methods applied to these neural networks,the loss is reduced gradually.When the loss decreases to a preset minimum,the neural network approaches a numerical solution for both angular flux density and antiderivative functions.This paper presents a numerical verification of geometries such as flat plates and spheres.It verifies the validity of the theoretical framework and associated methods.The study contributes to the development of novel technical approaches for applying deep learning to solve anisotropic scattering neutron transport equations in reactor engineering.
基金supported by the National Natural Science Foundation of China(Nos.12375157,12027902,and 11905011)。
文摘The quasi-monochromatic,continuously energy-tunable,and high-brightness gamma rays that are produced by an inverse Compton scattering(ICS)light source provide an ideal probe for gamma-ray imaging.However,owing to the influence of the intrinsic energy-angle correlation spectrum of this type of light source,monochromatic computed tomography(CT),especially in the gamma-ray energy region,can only be realized in a low-efficiency manner,similar to first-generation CT.A dual-energy scan scheme with a large imaging field of view(FOV)was developed in this study to improve the imaging efficiency.The effectiveness of this scheme was demonstrated based on the beam parameters of a typical ICS light source using Monte Carlo simulations.By leveraging the principle of basis material decomposition,the influence of the energyangle correlation spectrum on CT reconstruction was corrected,and a monochromatic CT image of the imaging object was accurately reconstructed.Furthermore,the electron density and effective atomic number of the imaging object could be obtained simultaneously.
基金supported by the National Natural Science Foundation of China(Grant Nos.12205274,12275251,12105270,12205272,12305262,and 12035002)the National Key Laboratory of Plasma Physics(Grant No.JCKYS2024212803)+2 种基金the Fund of the National Key Laboratory of Plasma Physics(Grant No.6142A04230103)the National Key R&D Program of China(Grant No.2023YFA1608400)the National Security Academic Fund(Grant No.U2430207).
文摘Stimulated Raman scattering(SRS)under a new ignition path that combines the advantages of direct-drive(DD)and indirect-drive(ID)schemes is investigated experimentally at the Shenguang-100 kJ facility.The results show that collective SRS in the plasma produced by ablating a polyimide film is detected for the ID beams,but is suppressed by adding a toe before the main pulse of the ID beams.The toe also strongly influences SRS of both the ID and DD beams excited in the plasma generated in the hohlraum.When a toe is used,the SRS spectra of the DD beams show that SRS tends to be excited in lower plasma density,which will result in a lower risk of super-hot electrons.Measurements of hot electrons support this conclusion.This research will help us produce a better pulse design for this new ignition path.
基金supported by the National Natural Science Foundation of China(Nos.62475121 and 62335012)。
文摘A scheme based on irregular V-shaped silicon nanoantennas is proposed to optimize transverse unidirectional scattering under plane wave irradiation.Traditional methods of designing regular shapes offer fewer parameters and higher search efficiency.However,due to the limitations of regular shapes,it is challenging to meet high-precision design requirements.Irregular shape design allows for a broader range of adjustments,but the complexity of shape parameters leads to lower search efficiency and a higher likelihood of converging to local optima.
基金financial support from the LASERLAB-EUROPE Access to Research Infrastructure Activity (Application No. 23068)carried out within the framework of EUROfusion Enabling Research Projects AWP21-ENR-01-CEA02 and AWP24-ENR-IFE-02-CEA-02+3 种基金received funding from Euratom Research and Training Programme 2021–2025 under Grant No. 633053supported by the Ministry of Youth and Sports of the Czech Republic [Project No. LM2023068 (PALS RI)]by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant Nos. XDA25030200 and XDA25010100)supported by COST (European Cooperation in Science and Technology) through Action CA21128 PROBONO (PROton BOron Nuclear Fusion: from energy production to medical applicatiOns)
文摘Recent experiments at the National Ignition Facility and theoretical modeling suggest that side stimulated Raman scattering(SSRS)instability could reduce laser–plasma coupling and generate considerable fluxes of suprathermal hot electrons under interaction conditions envisaged for direct-drive schemes for inertial confinement fusion.Nonetheless,SSRS remains to date one of the least understood parametric instabilities.Here,we report the first angularly and spectrally resolved measurements of scattered light at laser intensities relevant for the shock ignition scheme(I×10^(16)W/cm^(2)),showing significant SSRS growth in the direction perpendicular to the laser polarization.Modification of the focal spot shape and orientation,obtained by using two different random phase plates,and of the density gradient of the plasma,by utilizing exploding foil targets of different thicknesses,clearly reveals a different dependence of backward SRS(BSRS)and SSRS on experimental parameters.While convective BSRS scales with plasma density scale length,as expected by linear theory,the growth of SSRS depends on the spot extension in the direction perpendicular to laser polarization.Our analysis therefore demonstrates that under current experimental conditions,with density scale lengths L_(n)≈60–120μm and spot sizes FWHM≈40–100μm,SSRS is limited by laser beam size rather than by the density scale length of the plasma.
基金supported by the NASI Senior Scientist Fellowship project a DST research project (No. SR/S4/MS: 521/08)
文摘The problem of water wave scattering by a thin vertical elastic plate submerged in uniform finite depth water is investigated here.The boundary condition on the elastic plate is derived from the Bernoulli-Euler equation of motion satisfied by the plate.Using the Green’s function technique,from this boundary condition,the normal velocity of the plate is expressed in terms of the difference between the velocity potentials(unknown)across the plate.The two ends of the plate are either clamped or free.The reflection and transmission coefficients are obtained in terms of the integrals’involving combinations of the unknown velocity potential on the two sides of the plate,which satisfy three simultaneous integral equations and are solved numerically.These coefficients are computed numerically for various values of different parameters and depicted graphically against the wave number in a number of figures.
基金the financial support of Kermanshah University of Technology for this research under grant number S/P/T/1102
文摘The ability to precisely estimate the void fraction of multiphase flow in a pipe is very important in the petroleum industry. In this paper, an approach based on our previous works is proposed for predicting the void fraction independent of flow regime and liquid phase density changes in gas–liquid two-phase flows. Implemented technique is a combination of dual modality densitometry and multi-beam gamma-ray attenuation techniques. The detection system is comprised of a single energy fan beam,two transmission detectors, and one scattering detector. In this work, artificial neural network(ANN) was also implemented to predict the void fraction percentage independent of the flow regime and liquid phase density changes. Registered counts in three detectors and void fraction percentage were utilized as the inputs and output of ANN, respectively. By applying the proposed methodology, the void fraction was estimated with a mean relative error of less than just 1.2480%.
文摘In this paper, Method of Kobayashi Potential is used to determine the scattering behavior of a strip which is placed at the air-complex conjugate medium interface. And discussion is presented that how the complex conjugate medium mod-ify the scattering properties of the strip. A comparison is also given with that if we replace the conjugate medium with standard dielectric medium. E-polarized electromagnetic plane wave is supposed to be obliquely incident upon the ge-ometry. Scattered fields in both the half spaces are supposed in terms of unknown weighting functions. Discontinuous properties of Weber-Schafheitlin integral and orthogonal properties of Jacobi’s polynomials are used to determine these unknown weighting functions. Far scattered fields have been calculated using Saddle Point Method and computed for different parameters of interest.
基金supported by the National Natural Science Foundation of China(Nos.11505059,11575061)the Fundamental Research Funds for Central Universities(No.2017XS087)
文摘In neutron and photon transport problems,anisotropic scattering is of great importance for the particle flux,especially when the angular flux has a strong forward peak in shielding analyses.The conventional Legendre expansion is widely used in discrete ordinates transport codes because of algebraic simplifications with spherical harmonics for the scattering source.However,negative cross sections caused by the finitely truncated expansion may give rise to a negative source and flux.A simple method is adopted,based on integrating functions of scattering moments,to evaluate anisotropy and convergence of expanded functions.A series of problems were designed with angular fluxes of different anisotropy,and numerical simulations were performed using the ARES transport code to study different treatments and algorithms for scattering.Results show that the diagonal transport approximation is more stable and obtains a similar accuracy with the extended approximation.A conservative fixup for the negative source could ensure particle balance and improve computational accuracy significantly for photon transport.The effect of anisotropic scattering is problem-dependent,and no distinct differences among various methods are observed for volume source problems with a continuous energy source.For beam source problems,flux results are sensitive to negative scattering functions,and strictly nonnegative cross sections need to be implemented.
文摘The correspondence principle and the condition of supplementation were introduced by N. Bohr for the sub-mission of light phenomena, taking into account the wave nature of electromagnetic radiation on one hand, and its quantum structures on the other. In this paper, correspondence principle combines two models of matter, namely, the classical point of view of environment can be considered as an ensemble no equally-frequencies oscillators, i.e. electrons in the surrounding various atoms (molecules) of the matter and characterized by its own set of frequencies (but not hesitant in the absence of an energy source) and the quantum - environment could be presented as a set (ensemble) two-level systems, a wide range of Bohr fre-quencies. According to the correspondence principle Bohr jump-frequencies of atoms (molecules or nano particles) and natural frequencies oscillations of electrons of the same environment - oscillators are equal to each other. The dispersion characteristics of the environment in the every study range of optical frequencies correspond to the model of the classical harmonic oscillator of Lorenz, capable oscillates with Bohr fre-quency. Using the laws of classical mechanics to describe the environment and its dispersion properties, and the simultaneous presentation of light radiation in the form of a beam interacting with the environment of photons (quanta, corpuscles) helps explain peculiarities of the spectral composition Raleigh light scattered.
基金supported by the National Natural Science Foundation of China (No.12222502)。
文摘Muon scattering tomography(MST) is a powerful noninvasive imaging technique with significant applications in nuclear material detection and security screening.Traditional MST usually relies on the point of closest approach(PoCA) algorithm to reconstruct images from muon scattering data;however,PoCA often suffers from suboptimal image clarity and resolution.To overcome these challenges,we propose a novel approach that leverages reinforcement learning(RL) to enhance MST reconstruction,termed the μRL-enhanced method.By framing the MST optimization task as an RL problem,we developed an intelligent agent capable of dynamically adjusting the key PoCA parameters.The agent is trained using a multi-objective reward function that guides the optimization toward higher-quality reconstructions.Our experimental results show that theμRL-enhanced method significantly outperforms the traditional PoCA baseline acros s multiple benchmark metrics.Specifically,the proposed approach on average attains a 307% improvement in the intersection over union(IoU),a 79% increase in the structural similarity index measure(SSIM),and a 8.4% enhancement in the peak signal-to-noise ratio(PSNR) across four experiments.Furthermore,when benchmarked against the maximum likelihood scattering and displacement(MLSD)algorithm,the μRL-enhanced method offers modest gains in PS NR and IoU,together with a one-third increase in SSIM.These improvements demonstrate the enhanced reconstruction accuracy and structural fidelity of the μRL-enhanced method,highlighting its potential to advance MST technologies and their applications.
基金supported by the National Natural Science Foundation of China (Grant Nos. 62405231, 62405235, and 62575229)the National Key Laboratory of Space Target Awareness (Grant Nos. STA2024KGL0203, STA2024ZCA0203, and STA-24-04-05)+3 种基金the Beijing Key Laboratory of Advanced Optical Remote Sensing Technology (Grant No. AORS202405)the China Postdoctoral Science Foundation (Grant No. 2024M762527)the Shaanxi Province High-level Innovation and Entrepreneurship Talent Program (Grant No. H02439005)the Natural Science Foundation of Shaanxi (Grant Nos. S2024-JC-JCQN-60, S2025-JCQYTS-0107, and 2025JC-QYCX-05)。
文摘In complex media scattering,multiple scattering severely degrades the optical wavefront and results in blurred images,while the spectral distortion caused by the scattering effect leads to severe color distortion.Achieving color high-resolution imaging through scattering media remains a significant challenge.Here,we propose a broadband,polarization-based method for color high-resolution imaging through scattering media.This approach enables high-resolution reconstruction by effectively separating the speckle illumination pattern from the mixed-scattering field information,leveraging polarization common-mode characteristics.Concurrently,it incorporates chromatic balance compensation to correct spectral aliasing in the scattered light field,enabling color high-resolution imaging through complex scattering media.To further optimize color distortion caused by scattering,a compensation strategy combining color constancy and white balance theory is adopted.Experimental results demonstrate that the proposed method significantly enhances both spatial resolution and color fidelity across various scattering conditions and target materials,showcasing strong adaptability and robustness.This approach provides an effective solution for achieving high-resolution color optical imaging in complex scattering environments.
基金Project supported by the Project of the Anhui Provincial Natural Science Foundation(Grant No.2308085MA19)Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA0410401)+2 种基金the National Natural Science Foundation of China(Grant No.52202120)the National Key Research and Development Program of China(Grant No.2023YFA1609800)USTC Research Funds of the Double First-Class Initiative(Grant No.YD2310002013)。
文摘Small angle x-ray scattering(SAXS)is an advanced technique for characterizing the particle size distribution(PSD)of nanoparticles.However,the ill-posed nature of inverse problems in SAXS data analysis often reduces the accuracy of conventional methods.This article proposes a user-friendly software for PSD analysis,GranuSAS,which employs an algorithm that integrates truncated singular value decomposition(TSVD)with the Chahine method.This approach employs TSVD for data preprocessing,generating a set of initial solutions with noise suppression.A high-quality initial solution is subsequently selected via the L-curve method.This selected candidate solution is then iteratively refined by the Chahine algorithm,enforcing constraints such as non-negativity and improving physical interpretability.Most importantly,GranuSAS employs a parallel architecture that simultaneously yields inversion results from multiple shape models and,by evaluating the accuracy of each model's reconstructed scattering curve,offers a suggestion for model selection in material systems.To systematically validate the accuracy and efficiency of the software,verification was performed using both simulated and experimental datasets.The results demonstrate that the proposed software delivers both satisfactory accuracy and reliable computational efficiency.It provides an easy-to-use and reliable tool for researchers in materials science,helping them fully exploit the potential of SAXS in nanoparticle characterization.
