Irradiation Conditions Research Articles

One-Pot In Situ Construction of a Highly Stable Acylhydrazone-Derived Dy9 Cluster with Photodynamic Sterilization Property.

The extremely low stability of lanthanide clusters with precise structures and nanometer dimensions in aqueous solutions limits their application in the field of photodynamic sterilization. In this study, an hourglass-shaped nine-nucleated Dy9 cluster (1) with excellent light-driven reactive oxygen species (ROS) generation ability and photodynamic sterilization property was constructed using acylhydrazone multidentate chelating ligands obtained via an in situ reaction. The eight chelating ligands were distributed outside cluster 1, tightly wrapping the cluster core, thus preventing solvent molecules from attacking the cluster nucleus and ensuring the stability of cluster 1 in solution, which was demonstrated via X-ray diffraction and high-resolution electrospray ionization mass spectrometry (HRESI-MS). Time-dependent HRESI-MS monitoring of the self-assembly process of cluster 1 allowed two possible self-assembly mechanisms. The heavy atom effect of multiple Dy(III) ions in the Dy9 cluster enhanced the ISC pathway through spin-orbit coupling, promoting energy transfer from the excited singlet state (S1) to the triplet state (T1), which was stabilized, inducing the generation of more ROS. Cluster 1 showed a remarkable sterilization effect due to the generation of abundant ROS under light irradiation conditions. To our knowledge, this is a rare instance of lanthanide clusters with photodynamic sterilization, providing new horizons for the construction of fast and efficient sterilizers.

Triphenylamine Sensitized 8-Dimethylaminoquinoline: An Efficient Two-Photon Caging Group for Intracellular Delivery.

Triphenylamine-sensitized 8-dimethylaminoquinoline (TAQ) probes showed fair two-photon absorption and fragmentation cross sections in releasing kainate and GABA ligands. The water-soluble PEG and TEG-analogs allowed cell internalization and efficient light-gated liberation of the rhodamine reporter under UV and two-photon (NIR) irradiation conditions.

Different Biocompatibility and Radioprotective Activity of Squid Melanin Nanoparticles on Human Stromal Cells.

Squid ink melanin nanoparticles (NPs) have recently been demonstrated to have a number of bioactivities; however, their biocompatibility has been poorly investigated. In this study, we aimed to evaluate the effects of this NP on stromal cells, including human fibroblasts (hFBs), human umbilical vein endothelial cells (hUVECs), and human umbilical cord-derived mesenchymal stem cells (UCMSCs), and on the development of zebrafish embryos under normal X-ray irradiation conditions. The NPs showed high biocompatibility with low cytotoxicity, no cell senescence induction, and no effect on cell migration in hFBs or cell differentiation in UCMSCs. Nonetheless, this compound prevented cell movement in UCMSCs and significantly suppressed tube formation in hUVECs at a dose of 25 μg/mL. The NPs successfully penetrated the hUVECs but not the other two stromal cell types. The expression levels of functional genes involved in angiogenesis, apoptosis, antioxidant activity, and radiation sensitivity were altered in NPs subjected to hUVECs but were not affected in hFBs and UCMSCs. Melanin NPs significantly rescued cell viability and gene expression in irradiated hFBs and UCMSCs but not in hUVECs. In vivo treatments of zebrafish embryos showed that melanin NPs were nontoxic whether alone or under X-ray irradiation. These findings suggested that nanosized squid ink melanin had biocompatibility with selective stromal cells and was safe for early development.

Accuracy of EVC Method for the PiN Diode Pattern on SiC Epi-Wafer

In the previous report, we proposed the EVC (Expansion-Visualization-Contraction) method (Fig. 1) that effectively screens for malignant BPDs (basal plane dislocations) in the epi layer and near substrate interface, which expand to SSFs (Shockley-type stacking faults), leading to forward voltage degradation. The method intentionally utilizes the REDG (recombination enhanced dislocation glide) mechanism by UV (ultraviolet) irradiation in wafer sorting to replace the so-called burn-in (accelerated current stress) process, which is time-consuming during mass production. In this report, to verify the effectiveness of this method, we compared the SSFs expanded by forward biasing the PiN diode (Fig.3) on a wafer with the SSFs expanded by UV irradiating at the same PiN diode area where the metal electrode was removed by etching. The accuracy of the EVC method requires that SSFs expanded by forward biasing should be detected in the same positions as those of SSFs expanded by UV irradiation. Not all BPDs expand at the same time, but the number of expanded SSFs increases over time under constant forward current conditions. In this experiment, the current density was 400 A/cm2 for 8 minutes, and the excessive UV irradiation conditions was 143 W/cm2 for 20 minutes to avoid missing. Missing means the inability to check the SSFs expanded by forward biasing against the SSFs expanded by UV irradiation (Fig.2). For each diode electrode window, the presence or absence of SSFs were determined, and as shown in Table 2, 2 out of 49 window areas were missing, with the EVC method accuracy rate of 96 %.

Characteristics of solar to hydrogen-rich fuel production integrating parabolic trough collectors with partially rotatable tracking strategies

To achieve carbon neutrality, hydrogen and solar energy are receiving increasing attention. Concentrated solar thermal energy by parabolic trough collectors can be used to drive methanol cracking reactions for distributed hydrogen-rich syngas production. In this scenario, the collector is characterized by its small size and easy to integrate with hydrogen utilization equipment. However, parabolic trough collectors use a single-axis strategy with inherent large cosine loss, resulting in a low annual efficiency. The partially rotatable tracking is an advanced tracking strategy, which considers the trade-off between performance and cost compared to double-axis tracking strategies, and shows great potential for applications in distributed solar thermochemical reactions. In this study, solar to hydrogen-rich fuel production integrating parabolic trough collectors with the partially rotatable tracking strategy is proposed. The effect of the partially rotatable tracking strategy on the solar thermochemical conversion of methanol cracking is revealed. An annual normalized optical improvement of 40%∼54% is realized over a latitude range of 0∼50° by means of an optimal daily rotation angle. The solar thermochemical reactor with the partially rotatable tracking strategy has the less irreversibility loss during the concentrating process and the higher thermochemical efficiency. The results show that in three Chinese cities (Beijing, Lhasa and Guangzhou) with different latitudes and irradiation conditions, a partial north-south rotation strategy yields an additional 17.42%, 11.62% and 6.22% of chemical energy per year from the sun, while a partial east-west rotation strategy yields an additional 14.91%, 19.35% and 15.37% per year from the sun. The encouraging results indicate a promising method for the effective conversion of solar energy to chemical energy of hydrogen-rich fuels.

CdSe nanoflower as a new near infrared-activated photocatalyst for remediation of pharmaceutical wastewaters

Photocatalysis using Near Infrared (NIR) light is a promising method for a wide range of applications from environmental remediation. For this purpose, a flower-like cadmium selenide (CdSe nanoflower), as a new promising NIR-activated photocatalyst, was synthesized through a hydrothermal process and characterized using various spectroscopic and microscopic analytical techniques. The characterization results indicated that CdSe nanoflower is classified as an n-type semiconductor with a direct band gap of 1.7 eV (i.e., ECB = −0.7 V and EVB = 1 V indicated by Mott-Schottky analysis), and crystallite size and strain of 9.17 nm and 2.14, respectively. In the presence of various scavengers, the production of reactive oxygen species decreases, resulting in lower degradation efficiency. To investigate the photocatalytic efficacy, sulfamethoxazole (SMX) was used as a model pollutant drug molecule. The optimization of the process revealed that over 98% of SMX could be degraded under NIR irradiation and optimal conditions (pH = 7, photocatalyst dosage = 0.1 g, SMX concentration = 40 mg/L, time = 60 min), where Lagergren model with a correlation coefficient of 0.9765 was the best kinetic model describing the empirical results. The study indicates that CdSe nanoflower can be reused and regenerated up to 7 times with a 12% decrease in performance and after 60 min of degradation, the TOC concentration decreased by 81% in the best conditions. Additionally, CdSe nanoflower showed photodynamic microbial inactivation efficacy against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) under NIR light irradiation, where almost 95 and 99 % of bacteria was reduced in 20 min. The results of this work show CdSe nanoflower has great potential as a photocatalytic material with antimicrobial properties in the context of wastewater treatment and the management of microbial infections.

Technique of Reactor Experiments of Tin-Lithium Alloy Interaction with Hydrogen Isotopes Under Neutron Irradiation Conditions

The implementation of the ITER and DEMO projects currently includes the investigation of the structural and functional material properties of fusion reactors (FRs). Research to support the use of liquid metals and alloys as plasma-facing materials (PFMs) is a crucial area of work during the development of new FRs. Recent studies indicate the prospects of the tin-lithium (Sn-Li) alloy as a new liquid metal for protecting the in-vessel elements of a FR from the energy flows and high-density particles. Sn-Li alloy has been widely explored for utilization as PFM; however, there is a shortage of investigations being performed at nuclear reactors. The utilization of Sn-Li alloy as PFM in a FR must be fully justified by validated experimental results on tests under extremely high heat, plasma, and radiation loads. The paper presents the methodology of in-pile experiments performed at the IVG.1M research reactor (Kurchatov, Kazakhstan) to study the interaction of hydrogen isotopes with Sn-Li alloy under neutron irradiation conditions. A Sn-Li sample with 73 at. % tin and 27 at. % lithium was manufactured. A unique experimental ampoule device (AD) with a Sn-Li sample had been developed and manufactured for in-pile tests. The results of neutron-physical and thermophysical calculations of designs of the experimental device with Sn-Li alloy under irradiation conditions of the IVG.1M reactor were performed to justify the AD design. Methodical experiments were performed to determine the temperature dependence of the change in the composition of the gas phase in the chamber with Sn-Li alloy. The time dependence of the partial pressure of hydrogen, tritium, and tritium-containing molecules in the AD volume with the Sn-Li alloy on its temperature under reactor irradiation conditions at a power of 3 MW has been studied. Key findings include the successful measurement of tritium release, the determination of temperature conditions for tritium generation and release, and the validation of our experimental AD for conducting such studies.

Design of solar and energy storage systems fed reduced switch multilevel converter with flower pollination optimization

In the present situation, the growing use of power electronic devices and non-linear loads has led to power quality (PQ) issues, including harmonics and poor power factor, which adversely affect the distribution network. This study contributes a design of shunt active power filter, powered by solar energy and energy storage systems, to address these PQ issues. To minimize losses, a five-level reduced-switch voltage source converter has been considered. Additionally, a neural network-based reference signal generation method is used, eliminating the need for conventional synchronous reference frame and active-reactive power theories, along with their complex abc and αβ0 transformations. This work also includes the optimal selection of the shunt filter and the gain parameters for the proportional-integral-derivative (PID) controller used in the shunt and battery control system. These parameters, along with the weights and biases of the neural network, are optimally determined using a nature-inspired flower pollination optimization algorithm.The proposed system has three primary objectives: (1) stabilizing the voltage across the DC bus capacitor, (2) reducing total harmonic distortion (THD) and improving the power factor (PF), and (3) ensuring the power management under the varying irradiation and load conditions. The effectiveness of the proposed system is evaluated through three testing scenarios, with results compared to conventional SRF and pq methods using a proportional-integral controller (PIC). The analysis reveals that the THD for the case studies is 3.32 %, 2.93 %, and 3.98 %, significantly lower than the other techniques compared. Additionally, the PF is nearly at unity, with a lower settling time of 0.05 s for the DC bus voltage.

Study of irradiation temperature effect on radiation-induced polymorphic transformation mechanisms in ZrO2 ceramics

The influence of high-dose exposure to heavy Xe23+ ions on the alteration in optical and structural properties, alongside the polymorphic transformation degree in polycrystalline ZrO2 ceramics is considered in the paper. The focus on such studies is primarily due to the possibility of obtaining new data on the mechanisms of radiation-induced damage associated with exposure to heavy ions comparable to fission fragments of nuclear fuel, alongside the comparison of the observed changes in the damaged layer properties with the polymorphic transformation processes characteristic of ZrO2 ceramics. Analysis of the obtained data on alterations in the optical and structural features of ceramics contingent upon irradiation conditions revealed that, the irradiation temperature leads to less pronounced structural degradation caused by deformation distortions of OI-Zr-OI, Zr-OII, Zr-OI/OII and Zr-OI bonds, as well as the accumulation of oxygen vacancies in the damaged layer. At the same time, using a set of research methods, it was determined that at irradiation temperatures above 700 K the processes of polymorphic transformations t – ZrO2→ c – ZrO2 caused by radiation and deformation effects are less pronounced, which results in the formation of inclusions in the form of t – ZrO2.

Improving Radiometric Block Adjustment for UAV Multispectral Imagery under Variable Illumination Conditions

Unmanned aerial vehicles (UAVs) equipped with multispectral cameras offer great potential for applications in precision agriculture. A critical challenge that limits the deployment of this technology is the varying ambient illumination caused by cloud movement. Rapidly changing solar irradiance primarily affects the radiometric calibration process, resulting in reflectance distortion and heterogeneity in the final generated orthomosaic. In this study, we optimized the radiometric block adjustment (RBA) method, which corrects for changing illumination by comparing adjacent images and from incidental observations of reference panels to produce accurate and uniform reflectance orthomosaics regardless of variable illumination. The radiometric accuracy and uniformity of the generated orthomosaic could be enhanced by improving the weights of the information from the reference panels and by reducing the number of tie points between adjacent images. Furthermore, especially for crop monitoring, we proposed the RBA-Plant method, which extracts tie points solely from vegetation areas, to further improve the accuracy and homogeneity of the orthomosaic for the vegetation areas. To validate the effectiveness of the optimization techniques and the proposed RBA-Plant method, visual and quantitative assessments were conducted on a UAV-image dataset collected under fluctuating solar irradiance conditions. The results demonstrated that the optimized RBA and RBA-Plant methods outperformed the current empirical line method (ELM) and sensor-corrected approaches, showing significant improvements in both radiometric accuracy and homogeneity. Specifically, the average root mean square error (RMSE) decreased from 0.084 acquired by the ELM to 0.047, and the average coefficient of variation (CV) decreased from 24% (ELM) to 10.6%. Furthermore, the orthomosaic generated by the RBA-Plant method achieved the lowest RMSE and CV values, 0.039 and 6.8%, respectively, indicating the highest accuracy and best uniformity. In summary, although UAVs typically incorporate lighting sensors for illumination correction, this research offers different methods for improving uniformity and obtaining more accurate reflectance values from orthomosaics.

Halogenation Strategy: Simple Wide Band Gap Nonfullerene Acceptors with the BODIPY-Thiophene-Backboned Polymer Donor for Enhanced Outdoor and Indoor Photovoltaics.

Researchers have been motivated to develop photovoltaic systems that can efficiently convert artificial light into power with the growing use of indoor electrical devices for the Internet of Things. Understanding the impact of molecular design strategies involving morphological optimization through the terminal group of the non-fullerene acceptors (NFAs) is crucial. This is critically important to enhancing the photovoltaic efficiency of organic photovoltaic devices under diverse irradiation conditions. Halogenation of terminal groups proves to be a standout approach for adjusting energy levels, refining light-harvesting capabilities, crystallinity, and bolstering the intermolecular stacking in NFAs. Herein, we have designed two simple NFAs, DICTF-4F and DICTF-4Cl, to explore the dihalogenation (F and Cl) effect on the terminal group on the optical and electrochemical properties. After combining with the BODIPY-thiophene-backboned donor polymer P(BdP-HT), the organic solar cells (OSCs) using an optimized active layer with P(BdP-HT):DICTF-4F and P(BdP-HT):DICTF-4Cl attained a power conversion efficiency (PCE) of about 8.03 and 14.16%, respectively, under 1 sun illumination. Moreover, the OSC-based P(BdP-HT):DICTF-4Cl active layer showed a PCE approaching 24% under 1000 lx indoor conditions.

Readout circuit for a ZnO bulk-acoustic-wave X-ray dose rate detector

Bulk Acoustic Wave (BAW) resonators based on piezoelectric semiconductors are radio frequency devices that can convert X-ray dose rate into resonant frequency offset, which exhibit strong anti-interference capabilities and low power consumption and are suitable for wireless sensing systems. In this study, we designed a readout circuit for a ZnO BAW X-ray dose rate detector. (0001)-oriented ZnO single crystals were used to fabricate the high-quality BAW X-ray detector. Under dark field and X-ray irradiation conditions, the resonant frequency offset of the detector was recorded via the readout circuit. The readout circuit consists of an oscillator circuit based on a Pierce oscillator circuit structure, a frequency mixing circuit, and an STM32 microcontroller. This design offers higher frequency stability and lower phase noise. In practical applications, it can replace the expensive and bulky vector network analyzer for detecting and storing the resonant frequency of BAW resonators with the advantages of fast readout speed and portability.

Pre-exposure to peracetic acid followed by UV treatment for deactivating vancomycin-resistant Enterococcus faecalis through intracellular attack

Antimicrobial resistance (AMR) poses a global health threat to aquatic environments and its propagation is a hot topic. Therefore, deactivating antibiotic-resistant bacteria (ARB) and removing antibiotic resistance genes (ARGs) from water is crucial for controlling AMR transmission. Peracetic acid (PAA), which is known for its potent oxidizing properties and limited by-product formation, is emerging as a favorable disinfectant for water treatment. In this study, we aimed to assess the efficacy of pre-exposure to PAA followed by UV treatment (PAA-UV/PAA) compared with the simultaneous application of UV and PAA (UV/PAA). The focus was on deactivating vancomycin-resistant Enterococcus faecalis (VREfs), a typical ARB in water. Pre-exposure to PAA significantly enhanced the efficacy of subsequent UV/PAA treatment. At a UV fluence of 7.2 mJ cm−2, the PAA-UV/PAA method achieved a 6.21 log reduction in VREfs, surpassing the 1.29 log reduction observed with UV/PAA. Moreover, compared to UV/PAA, PAA-UV/PAA showed increased efficacy with longer pre-exposure times and higher PAA concentrations, maintaining superior performance across a broad pH range and in the presence of humic acid. Flow cytometry analysis indicated minimal cellular membrane damage using both methods. However, the assessments of superoxide dismutase (SOD) activity and adenosine triphosphate content revealed that PAA-UV/PAA induced greater oxidative stress under similar UV irradiation conditions, leading to slower bacterial regrowth. Specifically, SOD activity in PAA-UV/PAA surged to 3.06 times its baseline, exceeding the 1.73-fold increase under UV/PAA conditions. Additionally, pre-exposure to PAA amplified ARGs degradation and reduced resistance gene leakage, effectively mitigating the spread of AMR. Pre-exposure to 200 μM PAA for 10 and 20 min enhanced vanB gene removal efficiency by 0.14 log and 1.29 log, respectively. Our study provides a feasible approach for optimizing UV/PAA disinfection for efficient removal of ARB and ARGs.

Role of nitrogen and silver compounds in photocatalytic properties of carbon nanoparticle

To develop the photocatalytic method of water decontamination in an industrial scale, the structure of the photocatalyst should be modified in order to work under visible light irradiation. This paper is a report on a comparison of the efficiency of the photocatalytic activity of carbon, carbon nitride (CN) and carbon-silver (CAg) nanostructures for the degradation of Methylthioninium chloride in water. Carbon nanoparticles were synthesized by pulsed laser ablation (PLA) of a graphite target in distilled water. To synthesize CN nanocomposite, carbon nanoparticles were placed in normal pressure nitrogen-filled oven at 700 °C for 5 h. And to synthesize the CAg nanocomposite, bulk silver was ablated in the carbon nanoparticles solution by pulsed laser. Degradation was examined in dark condition and under the UV and visible light irradiations. Results show that the efficiency of photocatalytic activity of carbon dots as an abundant nanomaterial was increased, by their modification through atomic substitution (carbon nitride) and alloying (carbon-silver). Results show that the chemical properties of CN made this nanocomposite have the best performance among the 3 nanomaterials in dark and UV irradiated conditions, while the plasmonic absorption of silver nanoparticles made this material to have the best photocatalytic performance under visible light irradiation.

Degradation by photo-Fenton process using Fe-clay as heterogeneous catalyst under sunlight and microwave irradiation

This study presents a newly developed, highly efficient heterogeneous iron-based catalyst (Fe-CY), supported on treated bentonite clay (CY), designed for the degradation of methylene blue (MB) dye. The bentonite clay underwent a two-stage treatment involving physical and chemical processes to produce the designated treated clay (CY), which served as the support material for Fe-CY catalyst preparation using the wet impregnation technique. Subsequently, the performance of the resulting catalyst was assessed in a photo-Fenton reaction aimed at degrading MB dye under both solar and microwave irradiation conditions. To determine the optimal decolorization conditions, several variables, including catalyst dosage, H2O2 quantity, pH, and initial MB concentration in the reaction system, were systematically investigated. Miscellaneous characterization techniques were employed to assess the support, and prepared catalyst. X-ray diffraction (XRD) was used to determine crystallinity, scanning electron microscopy (SEM) to analyze morphological structure, Fourier-transform infrared spectroscopy (FTIR) to identify surface functional groups, energy dispersive X-ray (EDX) analysis for the purpose of elemental analysis, and Brunauer-Emmett-Teller (BET) for analyzing the textural properties. The experimental findings highlight the remarkable effectiveness of the catalyst in degrading methylene blue (MB). Upon exposure to sunlight and microwave irradiation, the catalyst achieved substantial MB color removal rates of 99.5% and 95.5% within 180 and 8 min, respectively. Moreover, the stability of the catalyst was evaluated across three consecutive cycles, revealing a sustained removal efficiency of 83.05%. Finally, a comprehensive investigation into the mechanism behind methylene blue (MB) removal was conducted, revealing insights into the unique catalytic properties of the Fe-clay catalyst.

Electrodeposition of WO3 Nanoparticles Onto a Carbon Membrane Surface for the Development of a Hybrid Filtration/Photocatalysis System

This study proposes the development of a photoactive filtration membrane using carbon fiber (CF) modified with an n-type semiconductor (WO3) to create a hybrid filtration/photocatalysis system applied in water treatment for simultaneous retention and degradation of the emerging contaminant (Sertraline - SER). The membrane was prepared through chemical electrodeposition in a three-electrode electrochemical cell, utilizing CF as the working electrode, two-dimensionally stable anode counter electrodes (De Nora), and an Ag/AgCl 4.0 mol L-1 KCl reference electrode. The preparation conditions included: 5.0 mmol L-1 of Na2WO4, 0.075% (v/v) H2O2, pH 1.4, with a potential of -0.5 V applied for 1 h, followed by heat treatment at 450 °C.Characterizations revealed a mesoporous structure, with UV-Vis absorption (300 - 700 nm), a band gap of 3.6 eV, and a BET surface area of 3.1 m2 g-1. Micrographs illustrated the formation of a uniform layer of WO3 on the CF surface, and characteristic peaks of C and WO3 in the monoclinic phase were confirmed. XPS analysis assigned species, including C 1s, O 1s, W (4f, 4f7/2, 4d5/2 4d3/2), with an intense peak at 530 eV related to the metallic bond (W-O).The optimized experimental conditions: SER 2.0 mg L-1, volume 100 mL, flow rate 180 mL min-1, pH 5.6, UV LED irradiation, complete removal of SER was observed in 30 min when applied to real effluents from a water treatment plant before and after the chlorination step. Additionally, complete degradation was achieved after 90 min of the experiment in simulated effluents in Milli-Q water. The photoactive membrane proved effective under various conditions, achieving 1.41 mg L-1 SER degradation after five reuse cycles and complete SER degradation after 40 min under solar irradiation. Experiments with scavenger agents confirmed the participation of species (HO•, O2 •-, 1O2, h+, and H2O2) in the degradation process. Additionally, six degradation products were identified with mass-charge (m/z) of 176, 189, 191, 273, 293, and 322, generated from hydroxylation, demethylation, and dechlorination reactions.The photoactive membrane has shown excellent potential for applications in filtration processes, mitigating issues associated with fouling. It facilitates the rapid removal and effective degradation of pollutants while also allowing for its application under various irradiation conditions. This feature simplifies and enables effective management in the treatment of contaminated waters.

Evaluation of the design features and components for a large-scale solar simulator for PV module testing

The evaluation of photovoltaic devices must be carried out in laboratories under stable conditions of irradiance, spatial uniformity, and spectral mismatch. Large-scale solar simulators are a reliable option for this. Various designs of simulators have been reported; however, more needs to be deepened in their study. In this work, an experimental investigation was conducted in order to explore the relationship between spatial non-uniformity, temporal instability, and the design features and components of a large-scale solar simulator based on metal halide lamps. The evaluation was based on the standard performance requirements of solar simulators, and various parameters were considered, including the geometry of the reflectors, the distance between reflectors, and the height of the lamps. In addition, the forces and deformations of the complete structure of the simulator, as well as the effects of the lamp orientation and the type of electrical supply, were analyzed. Based on the evaluation results of the design features and components, a simulator solar with an illuminated area of 1.7 m x 1.8 m was designed, constructed, and experimentally tested. A simulator class C was achieved, covering an area of 0.50 m x 0.50 m. The performance of the solar simulator was validated by experimental tests performed on commercial photovoltaic modules.

Etch-stop mechanisms in plasma-enhanced atomic layer etching of silicon nitride: A molecular dynamics study

Possible mechanisms of etch-stops in plasma-enhanced atomic layer etching (PE-ALE) for silicon nitride (SiN) were examined with molecular dynamics (MD) simulations. Recent experiments [Hirata et al., J. Vac. Sci. Technol. A 38, 062601 (2020)] have shown that the PE-ALE process of SiN consisting of hydro-fluorocarbon (HFC) adsorption and argon ion (Ar+) irradiation can lead to an etch-stop. The MD simulations have revealed that carbon (C) remnants at the end of a PE-ALE cycle can enhance further accumulation of C in the subsequent cycle. Under typical Ar+ ion irradiation conditions, nitrogen (N) atoms are preferentially removed from the surface over silicon (Si) atoms, and therefore, the SiN surface becomes more Si rich, which also promotes C accumulation by the formation of Si–C bonds. It is also seen that fluorine atoms contribute to the removal of Si, whereas hydrogen and C atoms contribute to the removal of N from the SiN surface.

Intelligent Solar System for Effective Renewable Energy

Photovoltaic (PV) systems are gaining popularity as a sustainable and renewable energy solution. Charge controllers play a crucial role in maximizing the energy harvested from PV panels and ensuring efficient battery charging. This study presents a comprehensive comparison between Pulse Width Modulation (PWM) and Maximum Power Point Tracking (MPPT) charge controllers, analyzing their performance, efficiency, and suitability for different PV system configurations. The analysis begins with an overview of PWM charge controllers, which regulate the charging process by rapidly switching the PV panel voltage on and off. PWM controllers are known for their simplicity, affordability, and reliability. However, their fixed voltage operation limits their ability to extract maximum power from the PV panels, especially in scenarios with varying solar irradiance and temperature conditions. In contrast, MPPT charge controllers employ advanced algorithms to continuously track the maximum power point (MPP) of the PV panels. By dynamically adjusting the operating voltage and current, MPPT controllers can optimize the power transfer from the PV panels to the battery bank. This capability results in higher energy harvesting, especially in situations with partial shading or non-ideal operating conditions.

Laser surface structuring of diamond-like carbon films for tribology

The paper overviews experimental findings of the direct laser processing and surface microstructuring (texturing) of various diamond-like carbon films (a-C:H, ta-C, DLN, metal-doped DLN), aimed at improvements of their tribological and nanotribological properties. The nanosecond UV and femtosecond IR/visible pulsed lasers were applied in microprocessing of the films, focusing on high precision surface structuring with fs-laser pulses. The studies were concentrated on the following tasks: (i) surface graphitization in laser microstructuring of the films under different irradiation conditions, (ii) lubricated friction performance of DLN films micropatterned with UV ns and visible fs pulsed lasers, and (iii) nanoscale friction of laser-structured DLN and metal-doped DLN films examined with contact-mode atomic force microscopy. The important findings of our studies are related to fabrication of highly-precise microgroove/microcrater patterns on DLN films and improvements of frictional properties of the laser-structured films at the macro, micro and nanoscale. The surface microstructures improved the film properties under oil-lubricated sliding in dependence on their geometrical parameters (size, depth, period) and ambient temperature. The nanoscale friction behavior of laser-structured films was shown to be controlled by the surface graphitization, nanoscale roughness, capillary forces and wear of AFM tips during friction force imaging.