Sample Thickness Research Articles

Influence of Layer Thickness and Shade on the Transmission of Light through Contemporary Resin Composites.

Material-dependent parameters have an important impact on the efficiency of light polymerization. The present in vitro study aimed to investigate the influence of the increment thickness and shade of nano- and nanohybrid resin composites on the transmission of curing light. Three contemporary resin composites were evaluated: Tetric EvoCeram® (TEC); Venus Diamond® (VD); and Filtek Supreme XTE® (FS XTE). Light transmission (LT) was recorded in accordance with the sample thickness (0.5 to 2.7 mm) and the shade. Polymerized samples were irradiated for 10 s each using the high-power LED curing light Celalux 2 (1900 mW/cm2). LT was simultaneously recorded using the MARC Patient Simulator (MARC-PS). LT was strongly influenced by the composite layer thickness. For 0.5 mm-thick samples, a mean power density of 735 mW/cm2 was recorded at the bottom side. For the 2.7 mm samples, a mean power density of 107 mW/cm2 was measured. Only LT was markedly reduced in the case of darker shades. From A1 to A4, LT decreased by 39.3% for FS XTE and 50.8% for TEC. Dentin shades of FS XTE and TEC (A2, A4) showed the lowest LT. The thickness and shade of resin composite increments strongly influences the transmission of curing light. More precise information about these parameters should be included in the manufacture manual.

Enhanced electromagnetic wave absorption in YAG-modified SiC foam

Electromagnetic technology applications are escalating, leading to increased human exposure to electromagnetic radiation. In addressing the challenges posed by this radiation, electromagnetic wave absorbing materials stand out due to their distinguished properties. This study focused on developing porous fibrous SiC three-dimensional (3D) foams. These were synthesized by freeze-drying SiC nanofiber dispersions followed by high-temperature sintering. Measurements demonstrated that the resulting SiC foams possess a relatively low density, approximating 0.1 g cm−3. Upon microscopic analysis, it became evident that the foam's porous structure is predominantly made up of SiC fibers intermixed with yttrium aluminum garnet granules. These tailored SiC foams delivered outstanding electromagnetic wave absorption characteristics, recording a minimum reflection loss value of −63 dB. Furthermore, an expansive effective absorption bandwidth of 6.9 GHz (spanning from 9.3 to 16.2 GHz) was noted for a sample thickness of 3.15 mm. Several factors contribute to this high absorption efficacy, including multiple reflections and both interface and dipole polarizations. It is also worth noting that the SiC foam displayed commendable oxidation resistance when exposed to elevated temperatures. Cumulatively, these findings underscore the promising potential of porous fibrous SiC 3D foams in electromagnetic wave absorption applications, especially in extreme conditions.

Nanocarbon/Co3O4/Epoxy Composites for Microwave Shielding and Absorption

The epoxy composite materials (CMs) with a random distribution of nanosized Co3O4 and carbon nanoparticles (graphite nanoplatelets GNP and carbon nanotubes CNT) are fabricated. Complex permittivity, permeability, and shielding properties of composite materials with 30 wt% of Co3O4 and (2–5) wt% of nanocarbon are measured in the frequency range of 1–67 GHz using the transmission–reflection method. A significant increase of microwave permittivity and presence of several peaks on the dependencies of the imaginary part of permittivity on the frequency are found for three‐phase nanocarbon/Co3O4/epoxy CMs. The observed microwave shielding efficiency of three‐phase epoxy composites is enhanced compared to two‐phase nanocarbon–epoxy composites. Such enhancement of shielding efficiency correlates with the increase of DC conductivity of these three‐phase composites. The measured complex permittivity and permeability spectra for nanocarbon/Co3O4/epoxy CMs are used for modeling the reflection loss for studied composites. It is shown that the most preferable for microwave absorption is the composites containing 2 wt% of nanocarbon filler for a sample thickness of 0.5–0.7 mm. The highest reflection loss  = 30 dB with an absorption bandwidth of 15 GHz is found for epoxy composite filled with 2 wt% of GNP and 30 wt% of Co3O4 for a sample thickness of 0.5 mm.

A non-beam-based Doppler broadening of positron annihilation radiation (DBAR) spectrometer for a single piece of micron-thickness film

Doppler broadening of positron annihilation radiation (DBAR) spectroscopy is a critical technique to provide electronic momentum information of materials. For conventional non-beam-based DBAR experiments, due to the continuous distribution of initial kinetic energy (0-545 keV) of positrons from 22Na source, two pieces of identical samples with sufficient thickness (> 1 mm for each sample with a density of 1 g/cm3) are required to stop almost all positrons in the samples. However, in many film studies, it is difficult or even impossible to meet this sample thickness requirement. In this work, judging by the output signals of a specially designed anticoincidence detector, the annihilation of positrons in a film sample and positron source are selectively collected. Furthermore, a new method is proposed to correct high-proportioned source components. Based on this, for the first time, a non-beam-based DBAR spectrometer was developed for a single piece of micron-thickness film. This approach will drastically broaden the application of DBAR spectroscopy in film characterization in future.

Generation of thermal neutron scattering data for GH3535 alloy

Recent studies related to the thermal neutron scattering (TNS) data in reactors were generally focused on fuels and moderators, while the TNS data for structural materials has received little attention. The TNS effect of the GH3535 alloy, a nickel-based alloy widely used in molten salt reactor (MSR), is studied in this work. The partial phonon densities of states (PDOS) for the main metals (Ni, Mo, Cr and Fe) in the alloy, which are required for the TNS data generation, are calculated using the density functional perturbation theory (DFPT) based on a special quasi-random structure (SQS) of the alloy. The TNS cross sections for the main metals in the alloy are generated using the modified NJOY code. To preliminarily validate the TNS data, the calculated scattering cross section, combined with the evaluated absorption cross section of the alloy, is compared with the experimental total cross section, which shows a good agreement. Moreover, an integral neutronics experiment of neutron leakage spectrum is designed to further validate the TNS data. The neutron leakage spectrum is simulated by the Monte Carlo method, which can be compared with the future experimental result. Based on the experiment geometry modeling, the TNS effects of the GH3535 alloy are analyzed at multiple incident neutron energies, sample thicknesses and temperatures, respectively. It is found that the TNS effect of the GH3535 alloy on the neutron leakage spectrum cannot be ignored, and the scattering cross section of the alloy with high precision should be included in designs of MSR.

An efficient pre-foamed method to fabricate low density poly(ether-block-amide) foams

Poly (ether-block-amide) PEBA foams have been widely used in many industrial fields. However, compared with amorphous polymers, the microcellular foaming process of PEBA is more complicated due to their complex phase morphology evolution behavior. Moreover, the productivity was limited owing to the long saturation time for thick samples. In this study, we proposed an efficient pre-foamed method to fabricate low density poly(ether-block-amide) foams. PEBA foams with controlled rather high density were firstly prepared by microcellular foaming under relatively low foaming temperatures. Afterwards, the pre-foamed PEBA sample with a high density were further foamed into much lower density by using secondary microcellular foaming under relatively high foaming temperature. The microphase separation phenomenon in PEBA was clearly studied by scanning transmission electron microscopy and atomic force microscopy-based infrared spectroscopy technique. Thanks to pre-foaming process, the diffusion rate of CO2 in PEBA matrix was greatly increased, resulting in shorter saturation time in microcellular foaming process. Most interestingly, pre-foaming process can also help PEBA achieve a higher expansion ratio compared with traditional microcellular foaming process with the same foaming parameters. Pre-foaming driven foaming process was a practical way of achieving low-density PEBA foams efficiently without adding new equipment, especially for thick parts.

Topological stability of spin textures in Si/Co-doped helimagnet FeGe

Element substitutions with magnetic or non-magnetic atoms are known to significantly impact the magnetic structure and related transport properties of magnets. To clarify the change of magnetic structure of B20-type magnets with element doping, we conduct real-space observations of spin textures and their temperature (T)-magnetic field (H) phase diagrams of a helimagnet FeGe with partially substituting Fe and Ge with Co and Si, respectively. The helical period (λ) changes dramatically by the element doping: λ increases by 147% to 103 nm in 30% Co-doped FeGe, whereas it decreases by around 70% to 49 nm in 30% Si-doped FeGe, compared to the λ =70 nm in FeGe. Upon applying the magnetic field normally to (001), (110), and (111) thin plates of both FeSi0.3Ge0.7 and Fe0.7Co0.3Ge, the hexagonal skyrmion crystal (SkX) state emerges. The magnetic phase diagrams observed through the real-space imaging reveal that (1) the SkX can extend to a larger T-H window by reducing the sample thickness or by cooling the sample under specific magnetic fields from temperatures above the transition temperature (TC ); (2) the stability of the SkX phase differs between Si-doped and Co-doped FeGe: the SkX phase is most unstable in the (111) FeSi0.3Ge0.7, while it remains robust in the (111) Fe0.7Co0.3Ge. These differences indicate distinct anisotropic behavior in FeGe with magnetic (Co) and non-magnetic-element (Si) dopants.

Self-cleaning, energy-saving aerogel composites possessed sandwich structure: Improving indoor comfort with excellent thermal insulation and acoustic performance

In the context of “carbon neutrality and emission peak”, aerogel that can meet national energy saving and emission reduction requirements while achieving efficient noise reduction has become a hot research topic. However, the development of multifunctional applications is greatly limited by the fact that pure aerogel usually exhibits relatively homogeneous properties. In this paper, SA@UGFW sandwich aerogel composites with functional silanes for structural strengthening were developed. SA@UGFW not only demonstrates ultra-lightweight (58 kg/m3) and high-strength properties (0.1 MPa) but also highly efficient self-cleaning capability (water contact angle ≈ 152.4°). The sandwich aerogel created super-efficient thermal insulation (0.015–0.017 W/(m·K)) and sound absorption performances (αmax = 0.93, NRC = 0.51, 9.77 mm). SA@UGFW exhibited a cold surface temperature of 54.2 ℃ and a ΔT of 145.8 ℃ when the heat source temperature was 200 ℃, despite the sample thickness of only 9.77 mm. At this point, ΔT was higher than 70 % of the heat source temperature. The thermal conductivity of SA@UGFW was as low as 0.00975 W/(m·K), even in −40 ℃ environment. In addition, the sandwich aerogel also showed 0.0204 W/(m·K) of low thermal conductivity following ultra-low temperature (-196 ℃) treatment for 168 h. Simulation results show that aerogel building insulation reduces heating energy savings by 31.00 % and cooling energy savings by 27.34 % compared to traditional insulation. Therefore, the sandwich aerogel with multiple functions reported in this paper achieved the enhancement of indoor comfort and was expected to be widely applied in the construction field.

Some characteristics of Cu/Cu2O/CuO nanostructure heterojunctions and their applications in hydrogen generation from seawater: effect of surface roughening

Cu/Cu2O/CuO heterojunction were synthesized, using thermal oxidation under the flow of argon and oxygen gas mixture, as efficient photoelectrode for hydrogen generation. The Cu/Cu2O/CuO heterojunction were synthesized using un-roughed and roughed Cu foils. The resulting heterojunction samples were characterized using various techniques. The evaluated oxide layer (Cu2O/CuO) thicknesses for un-roughed and roughed samples are 4.2 and 8.5 μm, respectively. XRD revealed that the oxide layer is a mix cubic Cu2O and monoclinic CuO crystalline phases with higher CuO ratio in the roughed sample. The surface morphology of the un-roughed sample is a porous surface that consisting of nanoflakes whereas surface morphology of the roughed sample is randomly oriented nanowires. The Cu/Cu2O/CuO nanostructured surface is superhydrophilic, with water contact angles of 11.12 and 0° for un-roughed and roughed samples, respectively. The roughed sample has higher absorbance over the entire studied wavelength range. The obtained values of the optical band gap for un-roughed and roughed samples are 2.48 and 2.39 eV, respectively. The photocurrent density of the roughed photoelectrode is much greater than that of un-roughed photoelectrode. The roughed photoelectrode has a photocurrent density of—0.151 mA cm−2 at—0.85 V and a photoconversion efficiency of 0.55% when illuminating with 340 nm light. This work offers a promised Cu/Cu2O/CuO photoelectrode for hydrogen generation from seawater.

Compact Mid‐Infrared Spectrometer Using Continuously Variable Infrared Filter and Microbolometer Array for Simple and Fast Measurement of Molecular Mid‐IR Spectra

AbstractThe mid‐infrared (mid‐IR) region is attractive for spectroscopy because this range has molecular fingerprint information. Existing FTIR‐based systems are limited by their complex optical systems, highlighting the ongoing necessity to advance miniaturization and simplify these systems. Here, a compact mid‐IR spectroscopy is introduced in the mid‐IR range, utilizing a continuously variable mid‐IR filter. This filter is made from Germanium (Ge) and BaF2 and is produced using physical vapor deposition. Continuously varying wavelengths of mid‐IR light are transmitted from different areas of the filter. These different wavelengths of light enter each pixel of the microbolometer array. Calibration is conducted using a sample material to match each pixel of the microbolometer array to its corresponding wavelength. Additionally, a deconvolution algorithm is applied to sharpen the acquired spectrum. This results in acquisition of high signal‐to‐noise ratio mid‐IR spectra in the LWIR region. Using this technology, mid‐IR spectroscopy for several types of samples like polymer film, and gas molecules is possible. In addition, by adopting total internal reflection, it is possible to measure non‐uniform thickness samples, such as liquid droplets.

Novel 3D-Printed lead-free radiation protection apron in the medical X-ray and thermal neutron energy range

In this study, we employed 3D printing technology to fabricate poly lactic acid (PLA) polymer samples infused with gadolinium oxide nanoparticles at additive rates of 10% and 20%. The objective was to explore their potential as radiation shielding aprons within the medical X-ray and thermal neutron energy spectrum. To facilitate comparisons, a PLA polymer sample with no additive was also produced. The homogeneity and well-defined structures of the PLA samples were observed using SEM and EDS analyses. Additionally, the excellent thermal stability of the proposed test samples was reported. In terms of gamma-ray shielding, there is a remarkable consistency between experiment, theory and simulation outcomes with a maximum discrepancy of approximately 5%. P-PLA-Gd20 sample exhibits attenuation capabilities against X-rays to a level that could serve as an alternative to lead. Additionally, the thermal and fast neutron attenuation effectiveness of the prepared samples were determined. A shielding effectiveness of 100% against thermal neutrons was achieved using a 10 mm sample thickness and the P-PLA-Gd20 sample. The findings consistently highlight the efficacy of the proposed polymer sample with a 20% gadolinium oxide nanoparticle additive, positioning it as a viable and promising alternative to traditional lead aprons.

Towards Construction of a Novel Nanometer-Resolution MeV-STEM for Imaging Thick Frozen Biological Samples

Driven by life-science applications, a mega-electron-volt Scanning Transmission Electron Microscope (MeV-STEM) has been proposed here to image thick frozen biological samples as a conventional Transmission Electron Microscope (TEM) may not be suitable to image samples thicker than 300–500 nm and various volume electron microscopy (EM) techniques either suffering from low resolution, or low speed. The high penetration of inelastic scattering signals of MeV electrons could make the MeV-STEM an appropriate microscope for biological samples as thick as 10 μm or more with a nanoscale resolution, considering the effect of electron energy, beam broadening, and low-dose limit on resolution. The best resolution is inversely related to the sample thickness and changes from 6 nm to 24 nm when the sample thickness increases from 1 μm to 10 μm. To achieve such a resolution in STEM, the imaging electrons must be focused on the specimen with a nm size and an mrad semi-convergence angle. This requires an electron beam emittance of a few picometers, which is ~1000 times smaller than the presently achieved nm emittance, in conjunction with less than 10−4 energy spread and 1 nA current. We numerically simulated two different approaches that are potentially applicable to build a compact MeV-STEM instrument: (1) DC (Direct Current) gun, aperture, superconducting radio-frequency (SRF) cavities, and STEM column; (2) SRF gun, aperture, SRF cavities, and STEM column. Beam dynamic simulations show promising results, which meet the needs of an MeV-STEM, a few-picometer emittance, less than 10−4 energy spread, and 0.1–1 nA current from both options. Also, we designed a compact STEM column based on permanent quadrupole quintuplet, not only to demagnify the beam size from 1 μm at the source point to 2 nm at the specimen but also to provide the freedom of changing the magnifications at the specimen and a scanning system to raster the electron beam across the sample with a step size of 2 nm and the repetition rate of 1 MHz. This makes it possible to build a compact MeV-STEM and use it to study thick, large-volume samples in cell biology.

Assessment of neutron and gamma-ray shielding characteristics in ternary composites: Experimental analysis and Monte Carlo simulations

The research aims to exploring the gamma-ray shielding capacities of polyacrylonitrile/chrome-filled polymer composites through a combination of experimental, theoretical and simulation methods. Additionally, employing MCNPv6 and GEANT4 simulation tools, the study evaluates the materials' performance against neutron radiation. The materials were subjected to various gamma-ray energy levels, and their shielding efficacies are analytically quantified using parameters such as Radiation Protection Efficiency (RPE), Mass Attenuation Coefficient (MAC), Linear Attenuation Coefficient (LAC), and Half-Value Layer (HVL). At various neutron energies and sample thicknesses, the numbers of transmitted neutrons were evaluated. Notably, composite P0Cr50 (not contain polyacrylonitrile and containing 50% chromium) emerges prominently, demonstrating superior radiation shielding characteristics against both gamma and neutron radiations. This attitude is attributed to its optimal chrome dispersion and density, positioning it as a promising candidate for radiation shielding applications in industrial and nuclear domains.

Color variation of composite resins in relation to the Vita Classical shade guide

Aim: The aim of this study was to verify the color variation between different composite resins and the Vita Classical Shade Guide. Methods: Two-millimeter thickness samples were made (n = 6) from eight commercial brands of composite resin (shade A2): Charisma (Kulzer), Forma (Ultradent), Harmonize (Kerr), Luna (SDI), Opallis (FGM), Oppus Bulk Fill (FGM), Vittra (FGM) and Filtek Z250 XT (3M ESPE). Specimens were stored in distilled water for 7 days and then polished. Color measurements of samples and A2 shade of the Vita Classical Shade Guide were performed using the Vita Easy Shade Advance 4.0 spectrophotometer on a black background. Color variations were calculated using the CIEDE2000 formula, considering values ≥0.81 being noticeable by the human eye and ≥1.77 being clinically unacceptable. Results were statistically analyzed with a 5% significance level. Results: Color variation (ΔE) of composite (E1 ) compared to the Vita Classical Shade Guide (E0 ) was greater than clinically acceptable for all the materials evaluated in this study. Forma (ΔE=2.08 ± sd=0.47) and Filtek Z250 XT (2.50 ± 0.20) had the smallest amount of color variation values found in the results. Harmonize (3.32 ± 0.63) presented values similar to Filtek Z250 XT, but it was worse than Forma. Vittra (3.51 ± 0.28), Charisma (3.80 ± 0.20), Opallis (4.24 ± 0.30) and Luna (5.67 ± 0.20) did not differ among each other and presented higher color variation than Forma, Filtek Z350XT and Harmonize. Oppus Bulk Fill (13.94 ± 1.12) was the composite with the greatest color variation. Conclusions: The findings in this study show that attention should be taken when using the Vita Color Shade Guide for composite shade selection.

Release kinetics and risk assessment of additives in plastic advertising banners

Plastic advertising banners (PABs) have been widely used for advertising and publicizing with large usage amount. The PABs are usually added with plenty of chemical additives for improving material performance, and the additives can be released during the lifetime of the PABs. However, limited knowledge is available on the composition and release of the additives in the PABs. In this study, benzenoids were found as the dominant additive categories in PABs. Release kinetics of benzenoid additives with high detection frequency and high abundance from the PABs under indoor and outdoor environments were investigated. During the 150-day release experiment, average release rates of the additives from the PABs under outdoor and indoor environments were 8.3 × 10−10 kg/m2·s and 6.3 × 10−10 kg/m2·s, respectively. The release rates of the additives were negatively related to the thickness of the PAB samples. Health risk assessment indicated that chemicals associated with PABs have potential carcinogenic risks to salesmen in the shopping malls. The risks of chemical exposure associated with PABs to consumers in the shopping malls were acceptable. This study unveils a considerable source of chemical exposure to humans.

One-step preparation of sea urchin-like conducting polypyrrole-modified porous carbonyl iron powders with excellent microwave absorption properties

Carbonyl iron powder (CIP) is a common microwave absorber frequently utilized to prepare microwave-absorbing materials. However, it exhibits only magnetic loss and no dielectric loss, which inevitably affects its wave-absorbing performance. Here, porous carbonyl iron powder (p-CIP) modified with conductive polypyrrole (PPy) was successfully prepared by one-step chemical etching and in-situ polymerization and then utilized to fabricate epoxy composites with high microwave absorption intensity. The scanning electron microscopy images revealed that conductive PPy was encapsulated on the surface of p-CIP. The reflection loss of the P-200 sample is −41.2 dB at 2.2 mm thickness. Reduction of the sample thickness to 1.8 mm resulted in a still acceptable reflection loss of −35.5 dB. Moreover, the effective absorption bandwidth widened to approximately 6.75 GHz (10.55–17.3 GHz). This provides a valuable approach for the development of microwave-absorbing materials with high absorption capacity.

Role of Substrate Roughness in Soil Desiccation Cracking

Soil desiccation crack is ubiquitous in nature, yet the physics of its initiation and propagation remain under debate, as it involves complex interactions across multiple fields of mechanics, hydraulics, and thermals. Here, an experimental attempt is made to uncover the role of substrate roughness on the soil desiccation process. The substrate roughness is deliberately fabricated by 3D printing, whereas the thickness of sample and environmental humidity are controlled to eliminate the effect of large hydraulic gradient. Four types of soils with varying expansibilities were desiccated on substrates with varying roughness. It reveals that: (1) soil desiccation crack evolution can be conceived as a competing process between the shear failure of soil-substrate interface, i.e., slippage of interface, and the tensile failure of soil, i.e., crack initiation, in minimizing the total energy of drying soil; (2) substrate roughness alters the failure mode and shear strength of soil-substrate interface and its sensitivity to moisture, thereby it regulates the pattern of how soil crack propagates upon drying; (3) soil expansibility is recognized as a key factor governing the crack-initiation point in addition to the widely recognized air-entry, and flaws in soil are the sources for the 120° crack angle and bimodal crack angle distribution.

The sound absorption properties of a double-leaf micro perforated panel (DL-MPP) made from a double-layered polypropylene material.

Micro-perforated panel sound absorbers are recognized as an alternative method for noise control, offering advantages over conventional porous absorbers. However, the sound absorption of a single micro-perforated panel (MPP) is limited in its ability to cover a broad range of frequencies, especially in the low-frequency region. Therefore, the primary focus of this study is to investigate the sound absorption performance of a double-leaf micro-perforated panel (DL-MPP) absorber, which aims to achieve high sound absorption across a wide frequency range. This study examines the impact of varying parameters, including perforation ratio, diameter of perforated holes, and air gap thickness, on the sound absorption characteristics of a polypropylene-based DL-MPP absorber. Polypropylene was used as the sound absorption material for this investigation. The DL-MPP absorber consists of two perforated panels installed parallel to a rigid back wall, with an air gap between them. To assess the sound absorption performance, a prototype of the DL-MPP absorber was fabricated and tested using a two-microphone impedance tube method following ASTM E1050 standard. The results demonstrate that the optimal sound absorption performance was achieved by designing the MPPs with a 1% perforation ratio, 1 mm diameter of perforated holes, and a 1 mm sample thickness.

Beam-hardening correction method for quantifying moisture content in cement paste based on X-ray radiography

The X-ray spectrum changes while traveling through specimen, and this phenomenon, known as the beam-hardening effect, breaks the linear relationship between the intensity variety on radiographs and material thickness. In the detection of water transport in cement-based materials, this effect leads to inaccurate results of the quantitative moisture distribution inside the sample, and it is difficult to eliminate this effect by gravimetric calibration. To solve this problem, this paper proposed a calibration strategy for the attenuation coefficient curve of cement-water two-phase specimens, and provided a heuristic mathematical model for fitting the 2D attenuation coefficient surface of cement paste specimens. The experiments showed that for zones close to saturation, beam-hardening leads to an overestimation of moisture content, while for a zone with a low water content, the X-ray radiography results without correction tend to underestimate it. After correction, the method showed a quantitative result close to that of the gravimetric method, and maintained a good stability in samples of different thickness.

High-energy-resolution off-resonant spectroscopy with self-seeded x-ray free-electron laser pulses.

This paper presents the implementation of high-energy-resolution off-resonant spectroscopy (HEROS) measurements using self-seeded x-ray free-electron laser (XFEL) pulses. This study systematically investigated XFEL conditions, including photon energy and accumulated shot numbers, to optimize the measurement efficiency for copper foil samples near the K-edge. The x-ray absorption spectra reconstructed using HEROS were compared with those derived from fluorescence-yield measurements. The HEROS-based spectra exhibited consistent line shapes independent of the sample thickness. The potential application of HEROS to high-temperature copper was also explored. HEROS offers distinct advantages including scan-free measurement of x-ray absorption spectra with reduced core-hole lifetime broadening and self-absorption effects. Using self-seeded XFEL pulses, HEROS facilitates single-shot-based pump-probe measurements to investigate the ultrafast dynamics in various materials and diverse conditions.