Search Results (467)

Most studies have focused on extending the applicability of the Ångström–Prescott equation and improving its accuracy in estimating solar irradiation. Only a limited number of studies have addressed atmospheric climatology using the Ångström–Prescott equation. In contrast, this study reformulates the Ångström–Prescott equation to explore its potential for extracting long-term atmospheric transparency information from radiometric measurements. It introduces a new annual formulation of the Ångström–Prescott equation derived from its common monthly version. While the formal structure is preserved, the equation shifts from its usual role, as a solar irradiation estimator, to a new role, as a predictor of long-term atmospheric transparency. The revised equation naturally defines an annual effective sunshine duration, which assigns greater weight to relative sunshine during summer months than during winter months. To enable prediction, the revised Ångström–Prescott equation is combined with Gaussian process regression. The equation provides the historical annual time series, while Gaussian process regression predicts future values and quantifies their associated uncertainty. To demonstrate the predictive capability of the method, it is applied to the analysis and prediction of four annual parameters characterizing atmospheric transparency: mean clear-sky atmospheric transparency, mean cloud transmittance, mean atmospheric transparency, and effective relative sunshine duration. The analysis is conducted using radiometric data collected at 14 stations distributed across Europe. Predictions for the upcoming decade (2024–2033) indicate that, at most stations, mean atmospheric transparency is expected to remain stable or change within approximate margins of −5% to +10%. Full article

In this explorative work, molybdenum trioxide (MoO₃) and representative doped MoO₃ materials, i.e., Cu-doped MoO₃ (2% Cu, “Cu-MoO₃”) and H-doped MoO₃ (H_0.31MoO₃, “H-MoO₃”), have been tested for the first time as photocatalysts in the UV-vis light-driven depolymerization of lignin. The catalysts have been characterized by XRD, TEM, ATR-FTIR, and UV-vis DRS. Under the adopted conditions (UV-vis irradiation, solvent 0.01 M aqueous NaOH, lignin 200 ppm, catalyst 1 g/L, rt, 5 h), photocatalytic depolymerization of wheat-straw lignin (WSL) produced increasing amounts of bio-oil on changing the catalyst from pristine MoO₃ to Cu-MoO₃ and H-MoO₃ (23%, 28% and 30%, respectively). Also, quantification of vanillin and vanillic acid shows a similar increasing trend. These results appear in line with the estimated band gap energies, which decrease in the order: MoO₃ (2.91 eV) > Cu-MoO₃ (2.86 eV) > H-MoO₃ (2.77 eV). H-MoO₃ shows the best catalytic performance, which was then fruitfully explored in the photocatalytic depolymerization of benchmark commercial Kraft lignin (bio-oil yield 32%, vanillin and vanillic acid yields 1.28% and 0.78%, respectively). In view of the results obtained, this work is expected to provide new ideas for the design of heterogeneous photocatalytic system for lignin cleavage. Full article

We present a rapid, energy-efficient, and ecofriendly route for the synthesis of alkaline earth titanate perovskites—CaTiO₃, SrTiO₃, and BaTiO₃—using an affordable, commercially available CO₂ laser engraver, commonly found in makerspaces and small-scale workshops. The method involves direct laser irradiation of compacted pellets composed of low-cost, abundant, and non-toxic precursors: TiO₂ and alkaline earth carbonates (CaCO₃, SrCO₃, BaCO₃). CaTiO₃ and BaTiO₃ were synthesized with phase purities exceeding 97%, eliminating the need for conventional high-temperature furnaces or prolonged thermal treatments. X-ray diffraction (XRD) coupled with Rietveld refinement confirmed the formation of orthorhombic CaTiO₃ (Pbnm), cubic SrTiO₃ (Pm3⁻m), and tetragonal BaTiO₃ (P4mm). Raman spectroscopy independently corroborated the perovskite structures, revealing vibrational fingerprints consistent with the expected crystal symmetries and Ti–O bonding environments. All samples contained only small amounts of unreacted anatase TiO₂, while BaTiO₃ exhibited a partially amorphous fraction, attributed to the sluggish crystallization kinetics of the Ba–Ti system and the rapid quenching inherent to laser processing. Transmission electron microscopy (TEM) revealed nanoparticles with average sizes of 50–150 nm, indicative of localized melting followed by ultrafast solidification. This solvent-free, low-energy, and highly accessible approach, enabled by widely available desktop laser systems, demonstrates exceptional simplicity, scalability, and sustainability. It offers a compelling alternative to conventional ceramic processing, with broad potential for the fabrication of functional oxides in applications ranging from electronics to photocatalysis. Full article

Scanning electron microscopy (SEM) is widely used for nanoscale imaging and the study of surface fine structure. However, its image quality is often limited by low secondary electron (SE) yield and surface charging, especially on insulating or micro-structured materials. In this study, we introduce a non-destructive technique that significantly improves SEM image acquisition by irradiating the specimen surface with ultraviolet (UV) light during observation. This approach leverages the photoelectric effect to enhance SE emission, resulting in a higher signal-to-noise ratio and improved image contrast in SEM imaging. Experiments were conducted using an in situ UV irradiation module on three representative samples: a 1 µm thick gold film (Au) deposited on a 525 µm thick silicon (Si) substrate, a black silicon (b-Si) sample, and a GaN substrate. The results demonstrate clear SE signal enhancement and effective charge mitigation under UV illumination. This UV-assisted SEM technique offers a simple and practical approach to improving electron-beam-based imaging and is expected to expand capabilities for high-contrast observation of nanoscale materials. Full article

This paper presents research on a naturally ventilated room with a façade opening covered by openwork grating. The first part describes experimental measurements of airflow velocity through the façade opening. Then, a numerical model of the room with the opening is introduced and validated using the experimental data. The core of the research consists of a series of numerical simulations in which the inflow and outflow of air are determined hour by hour using official data from a typical meteorological year and statistical climatic data for building energy calculations. Among the findings is a strong dependence of the opening performance on the façade orientation and the season of the year. For almost the entire year, excluding the daytime in July, the average ambient temperature is lower than the assumed inner temperature, which can cause heat losses due to air exchange (solar irradiation is not taken into account). The highest heat losses, close to 10 kW per window slot for all façades, are expected in February. The analysis confirms that, in temperate climates, natural ventilation is beneficial, especially when utilizing night cooling. The energy savings for a single window slot in July may reach up to 0.012 kWh/m². Full article

The issue of antibiotic resistance is becoming increasingly severe, urgently requiring the development of new antibacterial strategies. Photodynamic therapy (PDT) has gradually emerged as a promising alternative due to its spatiotemporal controllability, low risk of drug resistance, and broad-spectrum antibacterial properties. However, most existing photosensitizers (PSs) are hydrophobic, which limits their application efficiency in PDT. To address this problem, we designed and synthesized a water-soluble perylene diimide derivative (PDICN-CBn) as a photosensitizer. By introducing quaternary ammonium salt groups, its water solubility was improved, and antibacterial activity was enhanced. Subsequently, PDICN-CBn was assembled into silk fibroin/polylactic acid (SF/PLA) nanofibrous membranes via electrospinning technology, successfully constructing a visible-light-responsive ternary composite nanofibrous membrane (SF/PLA@PDICN-CBn). Using various characterization methods such as nuclear magnetic resonance (¹H-NMR), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), the microstructure, chemical composition, and structural characteristics of the nanofibrous membranes were systematically analyzed, verifying the successful synthesis of the photosensitizer and its assembly into the nanofibrous membranes. In the reactive oxygen species (ROS) experiment, electron spin resonance (ESR) spectra showed that PDICN-CBn efficiently generated singlet oxygen (¹O₂), superoxide anion (·O₂⁻), and hydroxyl radical (·OH) under visible light irradiation, confirming its ability to produce different types of ROS through both type I and type II photodynamic reactions. In the antibacterial experiments, Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and methicillin-resistant Staphylococcus aureus (MRSA) were selected for a series of tests, including plate-counting antibacterial assays, bacterial live/dead staining, and SEM observation of morphology. The results showed that 8 μg/mL of PDICN-CBn effectively destroyed the bacterial cell membrane structure and killed bacteria (bactericidal rate > 95%) after 2 h of visible light irradiation. This work successfully developed a novel visible-light-responsive SF/PLA@PDICN-CBn nanofibrous membrane with a dual antibacterial system combining photodynamic and electrostatic adsorption antibacterial properties, providing new ideas and methods for the design and development of photodynamic antibacterial materials. The prepared nanofibrous membrane has potential application values in fields such as wound dressings and medical protective materials and is expected to provide strong support for solving clinical infection problems. Full article

Solar-driven interfacial evaporation desalination technology offers a feasible solution to the global shortage of freshwater resources. However, previous interfacial evaporation technologies have often only focused on the production of freshwater resources, without fully utilizing the high-energy photons in sunlight and the salinity gradient generated after seawater evaporation. In this work, a solar-driven water–hydrogen–electricity (SWHE) co-production system integrated by solar-driven interfacial evaporation (SIE), interface photocatalytic hydrogen evolution (IPHE), and reverse electrodialysis (RE) was proposed. The aim is to enhance the efficiency of solar energy utilization and achieve simultaneous production of freshwater, hydrogen, and electricity. Under 2-sun irradiation, the SWHE device achieved a water generation rate of 0.77 kg m⁻² h⁻¹, a hydrogen generation rate of 8.57 mmol m⁻² h⁻¹, and a highest power density of 2.9 mW m⁻². Outdoor tests demonstrate that the cumulative water production reached 1.6 kg m⁻² over 6 h, with a total hydrogen yield of 12.22 mmol m⁻² and a highest power density of 0.095 mW m⁻², which validated the environmental adaptability of SWHE system. This novel design strategy is expected to provide a novel form of freshwater resources and energy supply for human society. Full article

To develop a full-color laser virtual reality head-mounted display (VR-HMD), a white laser light source, obtained by overlapping red–green–blue (RGB) lasers, is necessary. Although many studies on VR-HMD incorporating RGB lasers have been performed, there have been no studies on the removal of interferences such as electric field synthesis generated among the laser beams irradiated at a sample, namely “polarization crosstalk removal”. Therefore, the developing methods for electric field control are crucial. In this study, an attempt has been made to build a function that avoids crosstalk among the RGB beams after the irradiation of samples by separating them in time using the “time-shift” technique. If this function is realized, negative influences such as electric field synthesis can be eliminated. Consequently, the fabrication of the polarization-adjustable VR-HMD is expected in the future. Full article

The superconducting properties of YBa₂Cu₃${\mathrm{O}}_{7-\delta }$ thin films were investigated by conducting 1.7 MeV proton irradiations with a total fluence of $2.64\times {10}^{17}$${\mathrm{p}/\mathrm{cm}}^2$. The superconducting critical temperature ($T_c$) was reduced from 89.4 K to 10.1 K. The experimental procedure was similar to a previous study (0.6 MeV proton irradiation). We compared the effectiveness of $T_c$ suppression by varying the proton energy from 0.6 to 1.7 MeV and found that in general both protons of 1.7 MeV and 0.6 MeV were effective in suppressing the $T_c$ of YBCO. In particular, both results were consistent with the theoretical expectation (generalized d-wave AG theory) when a zero-temperature London penetration depth (${\lambda }_0$) = 215 nm is assumed for thin-film YBCO. For heavily irradiated cases (more than 80% $T_c$ suppression), however, 1.7 MeV protons were more effective in suppressing $T_c$ than 0.6 MeV protons. This can be understood by the fact that in the thin-film limit, higher-energy protons tend to produce less clustered point defects while lower-energy protons tend to create agglomeration of point defects. Full article

Accumulative rolling bonding (ARB) Cu/Nb nanolaminates have been widely observed to exhibit unique and large numbers of interface-based plasticity mechanisms, and these have been associated with the many extraordinary properties of the material system, especially resistances in extreme engineering environments (mechanical/pressure, thermal, irradiation, etc.) and ability to self-heal defects (microstructural, as well as radiation-induced). Recently, anisotropy in the interface shearing mechanisms in the material system has been observed and much discussed. The Cu/Nb nanolaminates appear to shear on the interface planes to a much larger extent in the transverse direction (TD) than in the rolling direction (RD). Related to that, in this present study we observe interface rotation in Cu/Nb ARB nanolaminates under constrained and unconstrained loading conditions. Although the primary driving force for interface shearing was expected only in the RD, additional shearing in the TD was observed. This is significant as it represents an interface rotation, while there was no external rotational driving force. First, we observed interface rotation in in situ rectangular micropillar compression experiments, where the interface is simply sheared in one particular direction only, i.e., in the RD. This is rather unexpected as, in rectangular micropillar compression, there is no possibility of extra shearing or driving force in the perpendicular direction due to the loading conditions. This motivated us to subsequently perform in situ microbeam bending experiments (microbeam with a pre-made notch) to verify if similar interface rotation could also be observed in other loading modes. In the beam bending mode, the notch area was primarily under tensile stress in the direction of the beam longitudinal axis, with interfacial shear also in the same direction. Hence, we expect interface shearing only in that direction. We then found that interface rotation was also evident and repeatable under certain circumstances, such as under an offset loading. As this behaviour was consistently observed under two distinct loading modes, we propose that it is an intrinsic characteristic of Cu/Nb interfaces (or FCC/BCC interfaces with specific orientation relationships). This interface rotation represents another interface-based or interface-mediated plasticity mechanism at the nanoscale with important potential implications especially for design of metallic thin films with extreme stretchability and other emerging applications. Full article

Experimental measurement of dose distributions is a pivotal step in the quality assurance of radiotherapy treatments, especially for those relying on high delivery accuracy such as hadron therapy. This study investigated the response of a polymer gel dosimeter to determine its suitability in performing geometric beam characterizations for hadron therapy under high-quenching conditions. Different extraction energies of proton and carbon ion beams were considered. Gel dose–response linearity and long-term stability were confirmed through optical measurements. Gel phantoms were irradiated with pencil beams and analyzed via magnetic resonance imaging. A multi-echo T₂-weighted sequence was used to reconstruct depth–dose profiles and transversal distributions acquired by the gels, which were benchmarked against reference data. As expected, a response-quenching effect in the Bragg peak region was noted. Nonetheless, the studied gel formulation proved reliable in acquiring the geometric characteristics of the beams, even without correcting for the quenching effect. Indeed, depth–dose distributions acquired by the gels showed an excellent agreement with measured particle range with respect to reference values, with mean discrepancies of 0.5 ± 0.2 mm. Single-spot transverse FWHM values at increasing depths also presented an average agreement within 1 mm with values determined with radiochromic films, thus supporting the excellent spatial resolving capabilities of the dosimetric gel. Full article

Recent advances in energy conversion technologies, especially solar-driven photocatalytic water splitting, are vital for satisfying the increasing global need for sustainable and clean energy. Perovskite oxides have attracted considerable attention among photocatalytic materials due to their tunable electronic structures, exceptional stability, and promise for effective hydrogen generation and environmental remediation. In this study, the optoelectronic and photocatalytic (PC) characteristics of ATiO₃ (A = Ca, Mg) perovskites, undoped and codoped with Se and Zr, have been analyzed using ab initio simulations based on the density functional theory (DFT). The calculated formation energies for codoped systems range from −1.01 to −3.32 Ry/atom, confirming their thermodynamic stability. Furthermore, band structure calculations indicate that the undoped compounds CaTiO₃ and MgTiO₃ possess indirect band gaps of 2.766 eV and 2.926 eV, respectively. In contrast, codoping alters the electronic properties by changing the band gap from indirect to direct and reducing its energy, resulting in the direct band gap values 2.153 eV, 1.374 eV, 2.159 eV, and 1.726 eV for the compounds ${{\mathrm{C}\mathrm{a}}_8\mathrm{T}\mathrm{i}}_7{\mathrm{Z}\mathrm{r}}_1{\mathrm{O}}_{23}{\mathrm{S}\mathrm{e}}_1$, ${{\mathrm{C}\mathrm{a}}_8\mathrm{T}\mathrm{i}}_6{\mathrm{Z}\mathrm{r}}_2{\mathrm{O}}_{22}{\mathrm{S}\mathrm{e}}_2$, ${{\mathrm{M}\mathrm{g}}_8\mathrm{T}\mathrm{i}}_7{\mathrm{Z}\mathrm{r}}_1{\mathrm{O}}_{23}{\mathrm{S}\mathrm{e}}_1$, and ${{\mathrm{M}\mathrm{g}}_8\mathrm{T}\mathrm{i}}_6{\mathrm{Z}\mathrm{r}}_2{\mathrm{O}}_{22}{\mathrm{S}\mathrm{e}}_2$, respectively. Additionally, this codoping improves light absorption and optical conductivity in the visible and ultraviolet ranges. These enhancements become increasingly evident with elevated dopant concentrations, leading to intensified light–matter interactions. Analysis of the band edge potentials reveals that the Se-/Zr-codoped CaTiO₃ compounds satisfy the necessary criteria for the photodissociation of water, conferring on them an ability to generate H₂ and O₂ under light irradiation. However, under different pH conditions, Se-/Zr-codoped MgTiO₃ is expected to perform better at higher pH levels, while Se-/Zr-codoped CaTiO₃ is more effective at lower pH levels. These findings highlight the promise of codoped materials for renewable energy applications, such as solar-driven hydrogen production and optoelectronic devices, with pH being a critical factor in enhancing their photocatalytic performance. Full article

This study develops a low-energy, high-precision nanoporous silicon process technology combining electrochemical etching with multi-wavelength laser irradiation and ultrasonic vibration to precisely control the size, porosity, and distribution of the nanoporous silicon structure and examines its potential applications in next-generation optoelectronic devices. This approach overcomes the challenges of poor pore uniformity and structural stability in conventional processes. The effects of different laser parameters, electrochemical conditions, and plasma bonding on the morphology are systematically analyzed. Additionally, the luminescence of the nanoporous silicon layer and its effectiveness in porous silicon diode devices were evaluated. Under 633 nm laser irradiation at 20 mW, the porosity reached 31.24%, exceeding that obtained with longer-wavelength lasers. The PS diode devices exhibited stable electroluminescence with a clear negative differential resistance (NDR) effect at 0~5.6 V. This technique is expected to significantly reduce energy consumption and simplify the manufacturing of silicon-based light-emitting devices. It also offers a scalable solution for next-generation silicon-based optoelectronic devices and advances the development of solid-state lighting and optoelectronics research. Full article

In recent years, electromagnetic waves (terahertz waves) with frequencies between 0.1 and 10 THz, which exist between radio waves and light waves, have attracted much attention. These electromagnetic waves have both the linearity of light waves and the transparency of radio waves and are expected to be applied to the field of human non-destructive testing. While it is known that terahertz waves can be used to detect foreign matter inside an object, we thought that by irradiating terahertz waves to the object to be measured from various directions, it would be possible to analyze the location and direction of contamination by comparing the scattering of the terahertz waves irradiated to the foreign matter. The samples were biomass resources in a jar with an opening of 53 mm and a diameter of 66.8 mm, and an aluminum plate 76 × 50 mm. When terahertz waves were irradiated from the side of the jar with the biomass resources in it, and the aluminum plate inserted, the transmission was higher when the metal plate was parallel to the light source and detector. This indicates that the transmission tendency of terahertz waves changes depending on the position and angle of the metal strip inside with respect to the direction of terahertz wave irradiation. This transmission tendency enables us to locate the position of a foreign object by irradiating terahertz waves from multiple directions, which is expected to be applied not only to the removal of foreign objects but also to various non-destructive inspections. Full article

Agrivoltaic technology holds great significance for promoting the collaborative development of new energy industries and modern agriculture. A systematic optimization design and preliminary electrical scheme for a 50 MW agrivoltaic power station in Shaanxi Province, China, were studied in this work. A combination of checkerboard and long-row layouts was adopted, considering the influence of the shading rate on agricultural production and photovoltaic power generation. The checkerboard pattern features the highest system efficiency, the smallest irradiance loss, and a slight lead in power generation, with a moderate shading rate, when compared to the other patterns. The expected energy gain from the bifacial modules’ rear side in this specific setup is 7.6%. These layouts ensure the power generation efficiency of the photovoltaic power station, while minimizing the shading impact of shading on crop growth, thereby achieving efficient comprehensive utilization of agricultural greenhouses and solar power generation. The primary electrical system was designed, including the main wiring design, main transformer selection, and type selection of major electrical equipment. The research results provide a practical reference for the large-scale application of agrivoltaic power stations, which is beneficial to promoting the high-quality development of modern agriculture. Full article