Search Results (293)

To improve the accuracy of three-dimensional (3D) reconstruction under microscopic conditions for laser-induced breakdown spectroscopy (LIBS), this study developed a novel visual platform by integrating an industrial CCD camera with a microscope. A customized microscale calibration target was designed to calibrate intrinsic and extrinsic camera parameters accurately. Based on the pinhole imaging model, disparity maps were obtained via pixel matching to reconstruct high-precision 3D ablation morphology. A mathematical model was established to analyze how key imaging parameters—baseline distance, focal length, and depth of field—affect reconstruction accuracy in micro-imaging environments. Focusing on trace element detection in WC-Co alloy samples, the reconstructed ablation craters enabled the precise calculation of ablation volumes and revealed their correlations with laser parameters (energy, wavelength, pulse duration) and the physical-chemical properties of the samples. Multivariate regression analysis was employed to investigate how ablation morphology and plasma evolution jointly influence LIBS quantification. A nonlinear calibration model was proposed, significantly suppressing matrix effects, achieving R² = 0.987, and reducing RMSE to 0.1. This approach enhances micro-scale LIBS accuracy and provides a methodological reference for high-precision spectral analysis in environmental and materials applications. Full article

With the great Clementine Gnomon in St. Maria degli Angeli, a 45 m pinhole meridian line, built in 1700–1702 upon the will of Pope Clemens XI, Francesco Bianchini inaugurated the Roman tradition of solar astrometry. We analyze two thousand dedicated observations at the Clementine Gnomon between 2018 and 2025, with solar altitudes from 20° to 71° and in various meteorological conditions, in order to assess the observational uncertainties on the solar diameter and their causes. We compare the meridian diameters measured by Bianchini near the winter solstices of 1701–1702 with the ones measured by Sigismondi in 2018–2025, reporting the observational errorbars per single measure and the systematic diminutions of the observed diameters with respect to the ephemerides, due to the turbulence and image contrast loss. Simulated datasets based on our measured uncertainties show that pinhole meridian lines cannot resolve solar diameter variations smaller than 1″ over 80 years. These limitations prevent tighter constraints on solar evolution across centuries using such instruments. Full article

Background/Objectives: Lutetium-177 is a widely used radioisotope in targeted radionuclide therapy, particularly for treating certain types of cancers relying on beta and low-energy gamma emissions, making it suitable for both therapeutic and post-therapy monitoring purposes. The purpose of this study was to evaluate the technical parameters for developing a prototype portable gamma camera dedicated to ¹⁷⁷Lu imaging applications. Methods: The well-validated GATE Monte Carlo toolkit was used to study the characteristics of the system and evaluate its performance in terms of spatial resolution, sensitivity, and image quality. For this purpose, a series of Monte Carlo simulations were executed, modeling a channel-edge aperture pinhole collimator incorporating a variety of computational phantoms. The final configuration of the prototype was standardized, incorporating the crystal size, collimator design, shielding, and the optimal FOV. After the development of the actual prototype camera, the system was also validated experimentally on the same setups as the simulations. Results: The final configuration of the prototype imaging system was standardized based on simulation results and then experimentally validated using physical phantoms under equivalent conditions. A minification of 1:5, spatial resolution of 1.0 cm, and sensitivity of 5.2 Cps/MBq at 10 cm distance source-to-collimator distance were assessed and confirmed. The experimental results agreed within 5% of simulated values. Conclusions: This study establishes the technical feasibility and foundational performance of a portable pinhole imaging system for potential clinical use in ¹⁷⁷Lu imaging workflows and thereby improving therapeutic effectiveness. Full article

The purpose of this study is to evaluate the potential impact of small aperture optics on corneal aberrations in post-RK patients. Preoperative data was evaluated from 32 eyes of 23 post-RK patients. Scheimpflug tomography was used to obtain measurements of corneal HOAs at 6-mm, 4-mm, and 2-mm corneal plane aperture diameters. The data was extrapolated using a non-linear fit to estimate HOAs that would be obtained with the 1.6 mm effective pinhole IOL aperture at the corneal plane for individual patients. The average RMS HOAs estimated for the 1.6 mm aperture was 0.063 ± 0.015 μm compared to 0.185 ± 0.029 μm for the natural pupil size. A postoperative RK case with an IC-8^® Apthera™ unilateral implantation demonstrated a 70% reduction in HOAs by objective measurement and prediction, plus a 2-line improvement in CDVA. Prediction modeling revealed that HOAs may be reduced in post-RK patients following pinhole IOL implantation, compared to the natural photopic pupil size. Furthermore, the approach can be used to guide which post-RK patients would benefit from a small aperture IOL during cataract surgery. Full article

This study comprehensively examines the barrier properties, aging behavior, and failure mechanisms of Parylene F-VT4 films, applied at four distinct thicknesses (0.3 µm, 0.6 µm, 0.9 µm, and 1.2 µm), as encapsulation layers for implantable medical devices. Parylene F-VT4, a fluorinated polymer known for its mechanical flexibility, thermal stability, and chemical inertness, is a promising candidate for long-term hermetic encapsulation. Parylene F-VT4 was uniformly deposited via a dedicated chemical vapor deposition (CVD) process typically used for Parylene depositions. The investigation of the Parylene F-VT4 films included pinhole density characterization, electrochemical impedance spectroscopy (EIS), and testing of coating lifetime based on the resistance of Cu meanders protected by Parylene F-VT4 when immersed in phosphate-buffered saline (PBS) under accelerated aging conditions (PBS at 60 °C) over 550 days. The EIS results demonstrated that thicker coatings (1.2 µm) exhibited excellent barrier properties and resistance to electrolyte penetration, whereas thinner coatings (0.3 µm and 0.6 µm) showed more rapid degradation due to microvoids and pinholes. The temporal evaluation of EIS spectra highlighted the gradual decrease in impedance magnitude, indicating the ingress of ions and water into the coating. The lifetime in PBS at 60 °C was determined by resistance-based lifetime measurements on Cu meander structures coated with Parylene F-VT4 coatings. The lifetime at 37 °C was calculated, assuming an acceleration factor of 2 per 10 °C increase in temperature, yielding lifetimes of approximately 25 days, 6.4 months, 2.3 years, and 4.5 years for 0.3 µm, 0.6 µm, 0.9 µm, and 1.2 µm coatings, respectively. These findings highlight the critical relationship between thickness and durability, providing valuable insights into the long-term performance of thin Parylene F-VT4 films for implantable devices. Full article

Despite the rapid efficiency advancement of perovskite solar cells (PSCs), non-radiative recombination at the buried interface between self-assembled monolayers (SAMs) and perovskite remains a critical bottleneck, primarily due to interfacial defects and energy level mismatch. In this study, we demonstrate a bifunctional interlayer engineering strategy by introducing 4,5-diiodoimidazole (4,5-Di-I) at the Me-4PACz/perovskite interface. This approach uniquely addresses two fundamental limitations of SAM-based interfaces: the insufficient defect passivation capability of conventional Me-4PACz due to steric hindrance effects and the poor perovskite wettability on hydrophobic SAM surfaces that exacerbates interfacial voids. The imidazole derivatives not only form strong Pb–N coordination bonds with undercoordinated Pb²⁺ but also modulate the surface energy of Me-4PACz, enabling the growth of pinhole-free perovskite films with preferential crystal orientation. The champion device with 4,5-Di-I modification achieves a power conversion efficiency (PCE) of 24.10%, with a V_OC enhancement from 1.12 V to 1.14 V, while maintaining 91% of initial PCE after 1300 h in N₂ atmosphere (25 °C), demonstrating superior stability under ISOS-L-2 protocols. This work establishes a universal strategy for interfacial multifunctionality design, proving that simultaneous defect suppression and crystallization control can break the long-standing trade-off between efficiency and stability in solution-processed photovoltaics. Full article

A theoretical model is presented for the accurate detection of a gas leak source through a pinhole in a cylindrical storage vessel using the acoustic emission (AE) technique. Pinholes of various diameters ranging from 0.20 to 1.2 mm were installed as leak sources, and safe N₂ was used as a filler gas. AE signals were measured and analyzed in terms of AE parameters (such as frequency, amplitude and RMS) as a function of angle and axial distance. Among them, the amplitude characteristic was the most important parameter to determine the leakage dynamics of AE with a continuous waveform. The simulation of AE amplitude was performed using the theoretical model for AE. For practical applications, the theoretical formula was modified into two semi-empirical equations by introducing the normalization method to fit the angular and axial characteristics of the observed AE amplitude, respectively. The main finding of this study is that the semi-empirical equations provide an accurate solution for leak source localization in the cylindrical vessel. As a priori knowledge, the value of ${\kappa }_{\eta }$ in Green’s function, which determines the angular and axial dependence of the AE amplitude, was determined by applying external excitation to the cylinder surface. The proposed formulas provide a suitable approach for practical application in the localization of leak sources in cylindrical storage tanks. Full article

Introducing nano-twins into electrolytic copper foil is an effective method to enhance strength and toughness. While pulse electrodeposition enables the easier preparation of high-density nano-twin copper, large-scale industrial production mainly relies on direct current electrodeposition. Therefore, systematically studying the effects of electroplating parameters on the microstructure and mechanical properties of direct current electrodeposited copper foil is crucial. In this paper, we discuss the effects of pH value, C_CuSO4, and J_k on the microstructure and mechanical properties of electroplated copper foils at room temperature. The results show that copper foils exhibit stronger (220)_Cu preferred orientation on the M surface than on the S surface with changes in pH value, C_CuSO4, and J_k. When the pH value is 2.5, the C_CuSO4 is between 70 and 90 g/L, and the J_k is within the range of 70–90 mA/cm², the prepared copper foil has better compactness and no obvious pinhole-like defects. Particularly, the copper foil electroplated with a pH value of 2.5, a C_CuSO4 of 80 g/L, and a J_k of 80 mA/cm² consists of equiaxed and columnar grains, featuring small grain size, uniform distribution, and a dense structure, resulting in excellent mechanical properties. Full article

As the crucial core material in aluminum–plastic-laminated films, aluminum foil serves as a barrier and shaping element for lithium-ion battery soft packaging. However, its thinness, measuring only tens of microns, makes it susceptible to the formation of pinholes during the manufacturing process, which can significantly impact the barrier performance and properties of the aluminum–plastic-laminated film. The morphology and composition of foreign particles that lead to pinholes were analyzed using scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS). Additionally, the formation mechanism and evolution law of pinholes were investigated using a laser scanning confocal microscope (LSCM). The results revealed that foreign particles responsible for pinholes originated from the inclusions in the aluminum alloy melt, filter aid particles from rolling oil, and environmental dust particles. To address this issue, potential strategies for controlling foreign particles were proposed. These included purifying the aluminum alloy melt, filtering the rolling oil, and maintaining a clean production environment. The simulated experiments showed that foreign particles were gradually embedded in the aluminum matrix during plastic deformation, leading to damage in the aluminum matrix. When the cumulative rolling reduction ratio exceeded 38%, the aluminum foil and foreign particles began to separate along the rolling direction, resulting in the formation of pinholes. The mechanism of uncoordinated deformation between foreign particles and aluminum foil was elaborated in detail. In addition, the simulation experiment indicated that once the cumulative reduction ratio surpassed 50%, the aspect ratio of the pinhole increased rapidly. When the cumulative reduction ratio increased to 83%, the pinhole began to gradually heal. Consequently, a quantitative relationship model between the pinhole area and the rolling reduction ratio was constructed. The pinhole evolution model enables a rough prediction of the actual pinhole area change and meets the requirements for engineering applications. This research provides both engineering applications and theoretical prediction approaches that can aid in the production of high-quality aluminum foil for lithium-ion battery soft packaging. Full article

CuCrO₂ (mcconnellite) was synthesized using both the solid-state method and microwave dielectric firing. It was characterized as a novel black ceramic pigment for use in various industrial glazes. For the first time, the application of mcconnellite (CuCrO₂) and its coloured glazes as selective solar absorbers (SSA) for integral ceramic solar collectors has been reported. The addition of quartz or anatase as colour modifiers was investigated to prevent the bluing of the pigment in Zn-containing glazes, a phenomenon associated with the exsolution of copper. Furthermore, doping with lanthanide oxides was explored to address two key challenges: controlling the formation of pinhole defects in porcelain glazes, which are linked to the destabilization of Cu⁺, and adjusting the IR cut-off wavelength to improve its performance as SSA. Full article

Full-field optical coherence tomography (FF-OCT) is a fast, en face interferometric technique that allows imaging inside a scattering tissue with high spatial resolution. However, camera-based detection, which lacks confocal gating, results in a suboptimal signal-to-noise ratio (SNR). To address this, we implemented a time-domain FF-OCT system that uses a digital micromirror device (DMD). The DMD allows us to scan multiple illumination spots across the sample and simultaneously realize confocal detection with multiple pinholes. Confocal imaging can also be demonstrated with line illumination and detection. Using a USAF target mounted behind a scattering layer, we demonstrate an order-of-magnitude improvement in SNR. Full article

Hybrid organic–inorganic perovskites have emerged as promising materials for next-generation optoelectronic devices owing to their tunable properties and low-cost fabrication. We report the synthesis of 3D hybrid perovskites with monoethanolammonium cations. Specifically, we investigated the optoelectronic properties and morphological characteristics of polycrystalline films of hybrid perovskites MA_xMEA_1−xPbI₃, which contain methylammonium (MA) and monoethanolammonium (MEA) cations. MA_xMEA_1−xPbI₃ crystallizes in a tetragonal perovskite structure. The substitution of methylammonium cations with monoethanolammonium ions led to an increase in the lattice parameters and the bandgap energy. Energy level diagrams of the synthesized samples were also constructed. The bandgap of MA_0.5MEA_0.5PbI₃ makes it a promising material for use in tandem solar cells. These polycrystalline films, namely MA_0.5MEA_0.5PbI₃ and MA_0.25MEA_0.75PbI₃ were fabricated using a one-step spin-coating method without an antisolvent. These films exhibit a uniform surface morphology under the specified deposition parameters. Within the scope of this study, no evidence of dendritic structures or pinhole-type defects were observed. All synthesized samples demonstrated photocurrent generation under visible light illumination. Moreover, using monoethanolammonium cations reduced the hysteresis of the I–V characteristics, indicating improved device stability. Full article

This study investigated the effectiveness of two lamination methods for integrating electrospun nanofiber membranes with woven nylon fabric for personal protective applications. The first method used a thermoplastic urethane (TPU) nonwoven adhesive, while the second method incorporated both the adhesive and a yarn, with the yarn embedding by sewing. Lamination with the TPU nonwoven adhesive slightly improved the adhesion between the nanofiber membrane and the nylon fabric. However, it decreased the air permeability, with the degree of the decrease depending on the areal density of the TPU adhesive. As the areal density of the TPU increased from 10 g/m² to 30 g/m², the air permeability decreased from 107.6 mm/s to 43.4 mm/s. The lamination resulted in a slight increase in the filtration efficiency for oil aerosol particles (0.3 µm, PM0.3, at a flow rate of 32 L/min) to 96.4%, with a pressure drop of 83 Pa. Embedding non-fusible yarns in the laminate increased the nanofiber/fabric adhesion and permeability. Still, the filtration efficiency and pressure drop were reduced to 74.4% and 38 Pa, respectively, due to numerous pinholes formed in the nanofiber layer during the sewing process. Conversely, incorporating fusible TPU yarns not only improved the interlayer adhesion by 175% compared to using TPU fabric adhesive alone but also increased the air permeability to 136.1 mm/s. However, the filtration performance (87.7%, 72 Pa) was slightly lower than that of the unlaminated nanofiber/fabric pack because the TPU yarns sealed the pinholes during lamination. Lamination embedded with hot-melt yarns provides a versatile approach for combining nanofiber membranes with conventional fabrics. It can be used to develop nanofiber-functionalized textiles for a wide range of applications, including fire protection, electrical insulation, sound absorption, filtration, marine applications, and more. Full article

Morphological changes in leukocytes are valuable markers for diseases and immune responses. In our earlier work, we presented Cellytics, a device that uses lens-free shadow imaging technology (LSIT) to monitor natural killer cell activity. Here, we present an improved Cellytics system that has been upgraded to a four-channel configuration to achieve higher throughput while maintaining robust reproducibility for rapid and cost-effective leukocyte analysis. The performance of this multi-channel Cellytics system was improved through refinements to the micro-pinhole chip. Etched pinholes provided better image resolution and clarity compared to drilled pinholes. To stimulate leukocytes, we used an activation stimulator cocktail (ASC) and quantified the resulting morphological changes using shadow-based metrics, including peak-to-peak distance (PPD) and maxima-to-minima standard deviation (MMD-SD). In addition, we developed a new leukocyte activation parameter (LAP) to specifically assess these activation-induced morphological changes. After ASC stimulation, leukocytes showed significantly increased PPD and LAP values and decreased MMD-SD compared to non-activated leukocytes. These results are consistent with the results of the flow cytometric analysis. These results emphasize the potential of Cellytics for the rapid and accurate assessment of leukocyte activation and provide a valuable tool for both clinical diagnostics and basic immunological research. Full article

This study focuses on the deposition of fullerene (C₆₀) as thin film on glass substrate by ultrasonic chemical bath deposition (UCBD) processing, under ambient temperature. Highly effective results were obtained from the films based on the solution of C₆₀ dissolved in toluene mixed with 2-methoxyethanol. The obtained films were characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). The XRD examination of the thin films reveals the presence of the C₆₀ cubic phase compared to the powder reference. The molecular structure obtained by Rietveld refinement shows no bonding between the molecules in C₆₀ powder, while in the deposed thin film the bonding is established. The molecules are bonded between them by pentagons of the right and left molecule. Each four neighbor molecules bond between them and they are all able to geometrically tie to the neighboring molecules under a crystalline FCC structure. The Sherrer and W-H methods were used to investigate microstructural parameters. The lattice parameter and the crystallite size show the same variation tendency. The average lattice parameter for the powder and the deposed films C₆₀-3h, C₆₀-5h, and C₆₀-8h is 14.0652, 14.1901, 14.0529, and 14.1848 Å, respectively, and the crystallite size calculated by the Sherrer method is 37.51, 38.98, 34.35, and 41.54 nm, respectively, as well. The IR spectrum indicated the presence of chemical π bonds (c=c) that are very suitable for enhancing the electronic properties of the material, and SEM analysis illustrated a dense, homogeneous without pinhole structures in the film morphology. Moreover, EDS emphasizes the presence of high carbon concentration and fewer stranger atoms. As a result, despite the UCBD technique being old and not very often applied in the field of organic materials, it is still a cost effective and good alternative method for organic thin film deposition. Full article