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Laser fabrication of structural bone: surface morphology and biomineralization assessment
摘要： The current work explores the surface morphology of the laser-ablated bone using Yb-fiber coupled Nd:YAG laser (λ = 1064 nm) in continuous wave mode. As the laser-ablated region contains physiochemically modified carbonized and nonstructural region, it becomes unknown material for the body. Thus, biomineralization on such a laser-ablated region was assessed by in vitro immersion test in noncellular simulated body fluid. The presence of hydroxyapatite was detected in the precipitated mineral product using scanning electron microscopy equipped with energy dispersive spectroscopy, and X-ray diffraction analysis. The effect of varying laser parameters on distribution of surface morphology features was identified and its corresponding effect on biomineralization was studied.
关键词： Laser-bone interaction,Surface morphology,Finite element method (FEM) modeling,Laser ablation
更新于2025-09-23 15:21:01
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Theoretical and Conceptual Framework to Design Efficient Dye-Sensitized Solar Cells (DSSCs): Molecular Engineering by DFT Method
摘要： Herein, eight new donor-p-acceptor organic dyes namely M1–M8 have been theoretically investigated for their potential in optoelectronic properties. The M1–M8 were designed through structural modi?cation of p-conjugated bridge of reference reported molecule IC2. The designed molecules contain Indolo[3,2,1-jk]carbazole as core donor unit and end capped cyanoacrylic acid as acceptor unit. DFT and TDDFT calculations using B3LYP, CAM-B3LYP, xB97XD and M062X functional were performed to evaluate the photophysical and photovoltaic properties. Results indicate that HOMO–LUMO energy gaps in M1–M8 have been found smaller than IC2. Among all, M7 is a material with lowest energy gap 2.61 eV, red shifted absorption wavelength value 436 nm. Results of the calculated redox potential of the ground state, vertical excitation energy of the dye, oxidation potential of the dye in the excited state, free energy change for electron injection, dye regeneration and open circuit photovoltage and light harvesting ef?ciency indicates that p-bridges in M1–M8 would show better power conversion ef?ciency than IC2. Especially, dye M7 with p-bridge 5-(thiazol-5yl)thiazole is found to be the most promising candidate for highly effective DSSCs properties. This theoretical framework may provide new ways for experimentalists to design high-performance DSSCs materials for optoelectronic applications.
关键词： Molecular modeling,p-conjugated linkers,Indolo[3,2,1-jk]carbazole,DSSCs
更新于2025-09-23 15:21:01
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Broad-band measurements of dielectric permittivity in coaxial line using partially filled circular waveguide
摘要： The full-wave analysis was applied for a coaxial line (i.e., transmission line) that has a “short-circuited” discontinuity. The discontinuity has a radius less than or equal to the inner radius of the coaxial line. The “sample region” can be considered as a partially filled circular waveguide. Such a structure is very practical and is of particular interest for the dielectric spectroscopy applications. It takes into account the inhomogeneous field distribution, which is the limiting factor for the determination of high dielectric permittivity values at microwave frequencies. The direct problem was solved by using the mode-matching technique, and the relationship between the complex reflection coefficient and the dielectric permittivity of the cylindrical sample was obtained. By solving the inverse problem, it is possible to obtain the complex dielectric permittivity from the experimental values of the scattering matrix. The results were verified by the finite element modeling of the system and applied for particular materials. The correspondence between these approaches is excellent. This method is very suitable for the determination of permittivity, which exceeds several thousands (it is applicable for any type of material). It extends the frequency range where the permittivity can be determined reliably. There is no necessity to prepare samples with different geometries (i.e., surface area and thickness).
关键词： dielectric permittivity,coaxial line,circular waveguide,mode-matching technique,finite element modeling
更新于2025-09-23 15:21:01
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Quantifying the amplified bias of PV system simulations due to uncertainties in solar radiation estimates
摘要： Solar radiation databases used for simulating PV systems are typically selected according to their annual bias in global horizontal irradiance (GHI) because this bias propagates proportionally to plane-of-array irradiance (GPOA) and module power (PDC). However, the bias may get amplified through the simulations due to the impact of deviations in estimated irradiance on parts of the modeling chain depending on irradiance. This study quantifies these effects at 39 European locations by comparing simulations using satellite-based (SARAH) and reanalysis (COSMO-REA6 and ERA5) databases against simulations using station measurements.
关键词： Satellite-based models,PV system simulation,PV system modeling,Reanalysis
更新于2025-09-23 15:21:01
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Design and Implementation of Fiber-embedded Plasmonic Structures in Microwires
摘要： General principles are developed using a finite element model regarding how time-dependent power dissipation of magnetic nanoparticles can be used to optimize hyperthermia selectivity. To make the simulation more realistic, the finite size and spatial location of each individual nanoparticle is taken into consideration. When energy input into the system and duration of treatment is held constant, increasing the maximum power dissipation of nanoparticles increases concentrations of energy in the tumor. Furthermore, when the power dissipation of magnetic nanoparticles rises linearly, the temperature gradient on the edge of the tumor increases exponentially. With energy input held constant, the location and duration of maximum power dissipation in the treatment time scheme will affect the final energy concentration inside the tumor. Finally, connections are made between the simulation results and optimization of the design of nanoparticle power dissipation time-schemes for hyperthermia.
关键词： treatment planning,finite-element modeling,Hyperthermia optimization,magnetic nanoparticles
更新于2025-09-23 15:21:01
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<i>(Invited)</i> Physics and Compact Modeling of SiGe HBT Linearity Using Mextram
摘要： This paper presents fundamentals of SiGe HBT RF linearity and its compact modeling using Mextram 504.12 and the latest Mextram, 505.00, for both common-emitter and common-base configurations. Collector-base junction depletion capacitance model is shown to be significant for accurate modeling of peak IP3 behavior, for which two new options are introduced in Mextram 505.00. Current dependence of avalanche factor is shown to be important for accurate modeling of IP3 peak. This is increasingly important in emerging RF applications requiring SiGe HBTs to operate at increasingly high VCB with negative IB.
关键词： SiGe HBT,compact modeling,IP3,RF linearity,Mextram,avalanche factor
更新于2025-09-23 15:21:01
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A forward approach for the validation of soot sizing??models using laser-induced incandescence (LII)
摘要： While validating the numerical modeling of the primary particle size distribution (PPSD) in sooting flames, a common practice is to compare the numerical results to the corresponding experimental data obtained with the Time-Resolved Laser-Induced Incandescence (TiRe-LII) technique. Since the PPSD is not directly measured by TiRe-LII, but derived with a post-processing procedure, various uncertainties and errors can potentially affect the consistency of such comparison requiring the estimation of many input parameters. On the contrary, nowadays, detailed numerical simulations provide access to a more complete set of data, which can be used to reconstruct the incandescence signal. In this work, a forward approach for the generic validation of numerical models for the PPSD is performed. It is based on the numerical reconstruction of the temporal evolution of the incandescence from the numerical results and its comparison with the measured signal. First, two indexes are proposed to quantify the agreement between the numerically synthesized and the measured signals. Then, the effectiveness of the proposed approach is demonstrated a priori by quantifying the potential errors that can be avoided with this new strategy compared to the classical approach. Finally, the feasibility of the proposed procedure is proven by comparing synthesized signals to the experimental ones available in the literature for a laminar premixed flame. It is shown that the proposed approach can be used for strengthening the analysis on numerical model performances in addition to the classical approach.
关键词： validation,soot sizing models,numerical modeling,primary particle size distribution,laser-induced incandescence
更新于2025-09-23 15:21:01
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Research and Modeling of Photovoltaic Array Channel Noise Characteristics
摘要： The photovoltaic array can be used as a medium for carrier communication to realize monitoring of photovoltaic components. Photovoltaic array channel noise, especially the pulse-type noise therein, seriously interferes carrier communication, so it is necessary to grasp the characteristics of the photovoltaic array channel noise. Photovoltaic array channel noise modeling is a key process when conducting anti-noise immunity tests of monitoring equipment. Based on the time-domain waveform of photovoltaic series channel noise which is measured in a photovoltaic power station, this paper proposes a photovoltaic array noise modeling method of Wavelet Peak-Type Markov chain, and studies the in?uence on modeling accuracy when different mother wavelets are adopted for modeling. From the simulation results, root mean square errors of the predicted output for Haar, Biorthogonal and Daubechies wavelet-based function modeling case are 0.9614 V, 1.4915 V and 0.7928 V, respectively, validating that Daubechies wavelet-based function is the best wavelet-based function of modeling. In the case that the peak of original noise reaches 20 V, the predicted mean absolute error of this model is only 0.4926 V, which not only veri?es the applicability of the Wavelet Peak-Type Markov chain model to the photovoltaic array channel noise, but also veri?es the applicability to the pulse-type noise.
关键词： photovoltaic array channel noise,noise characteristics and modeling,wavelet packet decomposition and recombination,Peak-Type Markov chain
更新于2025-09-23 15:21:01
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Spatial Retrieval of Broadband Dielectric Spectra
摘要： A broadband soil dielectric spectra retrieval approach (1 MHz–2 GHz) has been implemented for a layered half space. The inversion kernel consists of a two-port transmission line forward model in the frequency domain and a constitutive material equation based on a power law soil mixture rule (Complex Refractive Index Model—CRIM). The spatially-distributed retrieval of broadband dielectric spectra was achieved with a global optimization approach based on a Shuffled Complex Evolution (SCE) algorithm using the full set of the scattering parameters. For each layer, the broadband dielectric spectra were retrieved with the corresponding parameters thickness, porosity, water saturation and electrical conductivity of the aqueous pore solution. For the validation of the approach, a coaxial transmission line cell measured with a network analyzer was used. The possibilities and limitations of the inverse parameter estimation were numerically analyzed in four scenarios. Expected and retrieved layer thicknesses, soil properties and broadband dielectric spectra in each scenario were in reasonable agreement. Hence, the model is suitable for an estimation of in-homogeneous material parameter distributions. Moreover, the proposed frequency domain approach allows an automatic adaptation of layer number and thickness or regular grids in time and/or space.
关键词： soil measurements,electromagnetic scattering inverse problems,dielectric measurements,modeling,microwave propagation,dielectric materials
更新于2025-09-23 15:21:01
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Intimate contact development during laser assisted fiber placement: Microstructure and effect of process parameters
摘要： Intimate contact development under LAFP-specific thermal and mechanical boundary conditions/interactions and the effect of process parameters are investigated. One-layer, unidirectional strips of CF/PEKK material were placed with different process parameters on a flat tool surface to create different intimate contact conditions. The concept of effective intimate contact, which is based on the resin content at the surface, is introduced and a methodology to measure it from surface micrographs is provided. Degree of effective intimate contact measured from the samples was compared with the existing intimate contact models. The temperature history in the compaction zone was estimated with a finite element model and pressure sensitive films were used to determine the compaction pressure. It is shown that in addition to the squeeze flow mechanism, which is the base for the current intimate contact models, through-thickness percolation flow of the resin needs to be considered to explain the effective intimate contact development.
关键词： B. Microstructures,C. Process modeling,E. Automated fiber placement (AFP),A. Polymer-matrix composites (PMCs)
更新于2025-09-23 15:21:01