Irradiation Time Research Articles

Wireless sequential dual light delivery for programmed PDT in vivo

Using photodynamic therapy (PDT) to treat deep-seated cancers is limited due to inefficient delivery of photosensitizers and low tissue penetration of light. Polymeric nanocarriers are widely used for photosensitizer delivery, while the self-quenching of the encapsulated photosensitizers would impair the PDT efficacy. Furthermore, the generated short-lived reactive oxygen spieces (ROS) can hardly diffuse out of nanocarriers, resulting in low PDT efficacy. Therefore, a smart nanocarrier system which can be degraded by light, followed by photosensitizer activation can potentially overcome these limitations and enhance the PDT efficacy. A light-sensitive polymer nanocarrier encapsulating photosensitizer (RB-M) was synthesized. An implantable wireless dual wavelength microLED device which delivers the two light wavelengths sequentially was developed to programmatically control the release and activation of the loaded photosensitizer. Two transmitter coils with matching resonant frequencies allow activation of the connected LEDs to emit different wavelengths independently. Optimal irradiation time, dose, and RB-M concentration were determined using an agent-based digital simulation method. In vitro and in vivo validation experiments in an orthotopic rat liver hepatocellular carcinoma disease model confirmed that the nanocarrier rupture and sequential low dose light irradiation strategy resulted in successful PDT at reduced photosensitizer and irradiation dose, which is a clinically significant event that enhances treatment safety.

Use of UV-C radiation and packaging to maintain the quality of minimally processed kale

Kale, a imortant crop for family farms, gains added value through minimal processing, enhancing freshness and convenience. UV-C irradiation emerges as a promising method for extending kale's shelf life without chemicals, although standardization is complex due to varying food resistances to light penetration.The study in question analyzed the effects of two different irradiation times on minimally processed cabbage, packaged in bowls and Styrofoam with plastic film, observing changes in physical-chemical and sensory parameters, such as loss of mass, color, pH, and visual and olfactory signs of deterioration. Six treatments were tested, varying the exposure time and the type of packaging, as well as a treatment with chlorinated sanitizer, using the Tukey test at 5% significance to determine the most effective in preserving the product. It was found that the packaging in the cumbuca resulted in less mass loss compared to the tray, and the lowest pH values were recorded in the treatment with UV-C light in the cumbuca, which may indicate that they are an option for reducing the stress of the product after processing. None of the color parameters a* and b* or the luminosity index differed from each other, so it is valid to say that the UV-C radiation and chlorine sanitization treatments applied in the experiment were able to preserve the color of the cabbage samples for a period of 8 days. Therefore, the application of UV-C light did not negatively affect the color, pH or loss of mass of the minimally processed cabbage and combined with the correct packaging can be an alternative to conventional sanitization, in addition to maintaining the original aroma of the product.

EXPLORING THE IN‐SITU DEVELOPMENT OF A 1D/2D GADOLINIUM IRON OXIDE/TUNGSTEN DISULFIDE PHOTOCATALYST TO IMPROVE TETRACYCLINE DEGRADATION MEDIATED BY VISIBLE LIGHT

In the field of photocatalysis, heterojunction photocatalysts have garnered a lot of attention due to their high‐efficiency interfacial charge‐transfer property and their nanoarchitecture. Herein, GdFeO3/WS2is successfully synthesized by the in‐situ growth method and holds significant catalytic properties and efficient degradation for tetracycline. Using WS2 as a co‐catalyst could reduce e‐ and h+ recombination, improving GdFeO3's photocatalytic performance. The GdFeO3/WS2 possesses a bandgap of 1.9 eV, 178.9 m2 g−1 specific surface area, 0.2 nm pore size, and a lifespan of 6 ns. The optimal GdFeO3/WS2 photocatalyst exhibits a maximum removal of 96.2% at a tetracycline concentration of 10 mg/L, a pH of 3, and 40 mg of photocatalyst in an irradiation time of 90 min. Tetracycline has a higher photocatalytic efficiency in visible light (96.2%) than in sunlight (72.6%). Trapping tests revealed that the major reactive species for tetracycline removal in an aqueous solution are •OH, and •O2‐. The recycle experiment shows no deactivation of the GdFeO3/WS2 photocatalyst after 5 recycles. This study sheds light on the rational design of the GdFeO3/WS2 photocatalyst as a potential material for treating wastewater.

Enhancing Domestic Wastewater Treatment: A Study on the Efficacy of Tiered Filtration and a Combined Photocatalytic Ozonation Methods

This study aimed to construct an optimized reactor using photocatalytic ozonation, and its effectiveness was determined using PermenLHK No. 86/2016. The Tanjung Uma housing estate in Batam city was selected as the study sample site for domestic wastewater because of its role as a significant water body that receives liquid waste from a majority of activities across the city. The experiment employed a quantitative research approach and a true experimental approach, testing variables (catalyst weight, UV irradiation time, and ozonation duration) in a laboratory setting (25°C and 40-70% Humidity). The study found that the optimized parameter (a combination of 2 h of irradiation, with 2 g of TiO2 along with 5 min of ozonation) resulted in a significant difference in water quality parameters compared to before treatment with 92% effectivity. It can be concluded that this Reactor prototype was highly successful in reducing environmental impacts based on its effectiveness

Controllable defects in monolayer graphene induced by hydrogen and argon plasma

Abstract Graphene has attracted wide attentions since its successfully exfoliation. Honeycomb sp2 carbon lattice and Dirac semi-metal band structure make graphene a promising material with excellent mechanical strength, thermal conductivity, and carrier mobility. However, the absence of intrinsic bandgap limits its application in semiconductor. Defects in graphene is supposed to modify its band structure and lead to an opened bandgap. Many methods have been demonstrated to introduce defects into graphene, such as chemical reaction, plasma, electron beam, and laser. However, the species of defects are mostly uncontrollable in most treatment processes. In this study, we report three kinds of defects can be controllably induced in graphene via hydrogen (H2) and argon (Ar) plasma. With different parameter and feeding gas, hydrogenated graphene, graphene nanomesh and graphene with vacancies can be well obtained. The defect density can be precisely controlled by tuning plasma power and irradiation time. Morphological, spectroscopic, and electrical characterizations are performed to systematically investigate the defect evolution. Graphene nanomesh and graphene with vacancies show obvious difference for roughness and coverage, whereas the morphology of hydrogenated graphene remains similar with that of as-prepared graphene. For hydrogenated graphene, an opened bandgap of ~20 meV is detected. For graphene nanomesh and graphene with vacancies, the semiconductive on/off behaviors are observed. We believe this work can provide more details of plasma-induced defects and assist the application of graphene in semiconductor industry.

Novel nanostructure approach for antibiotic decomposition in a spinning disc photocatalytic reactor

Conventional wastewater treatment processes are often unable to remove antibiotics with resistant compounds and low biological degradation. The need for advanced and sustainable technologies to remove antibiotics from water sources seems essential. In this regard, the effectiveness of a spinning disc photocatalytic reactor (SDPR) equipped with a visible light-activated Fe3O4@SiO2-NH2@CuO/ZnO core–shell (FSNCZ CS) thin film photocatalyst was investigated for the decomposition of amoxicillin (AMX), a representative antibiotic. Various characterization techniques, such as TEM, FESEM, EDX, AFM, XRD, and UV–Vis-DRS, were employed to study the surface morphology, optoelectronic properties, and nanostructure of the FSNCZ CS. Key operating parameters such as irradiation time, pH, initial AMX concentration, rotational speed, and solution flow rate were fine-tuned for optimization. The results indicated that the highest AMX decomposition (98.7%) was attained under optimal conditions of 60 min of irradiation time, a rotational speed of 350 rpm, a solution flow rate of 0.9 L/min, pH of 5, and an initial AMX concentration of 20 mg/L. Moreover, during the 60 min irradiation time, more than 69.95% of chemical oxygen demand and 61.2% of total organic carbon were removed. After the photocatalytic decomposition of AMX, there is a substantial increase in the average oxidation state and carbon oxidation state in SDPR from 1.33 to 1.94 and 3.2, respectively. Active species tests confirmed that ·OH and ·O2− played a dominant role in AMX decomposition. The developed SDPR, which incorporates a reusable and robust FSNCZ CS photocatalyst, demonstrates promising potential for the decomposition of organic compounds.

INVESTIGATING THE EFFECT OF HYDROGEN PEROXIDE ON PHOTOCATALYTIC DEGRADATION OF COMMERCIAL PARACETAMOL USING TiO2

The role of hydrogen peroxide on paracetamol degradation was investigated. Photocatalysis system contains UV radiation and commercial titania (TiO2 ) as catalyst. The parameters studied for optimal photocatalysis conditions were catalyst dose (0.05 - 0.2 g), initial concentration of paracetamol (5 - 20 mg L-1), and irradiation times (0 - 210 min). Optimal condition obtained by determining the changes of paracetamol concentration converted to be degradation percentage. The influence of hydrogen peroxide concentrations (1 % - 7 %) on photocatalysis TiO2 system was studied. The highest paracetamol degradation was obtained at addition of 3 %. It gives positive effect on degradation process. Thus, hybrid process (UV / TiO2 / H2O2 ) is more effective in comparison to the process UV/ TiO2 and UV/H2O2. Paracetamol (5 mg L-1) was degraded about 90.80 % using 0.1 g TiO2 , 3 % H2O2 addition for 180 min. According to the GC-MS analysis results, paracetamol degradation forms new less toxic by-products. The hybrid process is an alternative technique for degradation of wastewater containing paracetamol.

Beta-Irradiation of pure 1-alkyl-3-methylimidazolium-based ionic liquids

Abstract1-Alkyl-3-methylimidazolium ionic liquids are common cellulose solvents and biomass pretreatment agents, while beta-irradiation (“e-beaming”) is often used to decrease the recalcitrance of biomass towards hydrolysis or saccharification. Aiming at the general goal of elucidating the interaction between lignocellulosics, imidazolium-based ionic liquids, and beta-irradiation, we studied the effect of beta-irradiation on the pure ILs 1-ethyl-3-methylimidazolium and 1-butyl-3-methylimidazolium, both as chloride and acetate. Contrary to the expectation of inertness, irradiation caused degradation of the ILs, which was proportional to irradiation dosage, i.e., to irradiation time and intensity. At a dosage of 2400 kGy, 0.2% (2000 ppm) of the IL were chemically altered. The main degradation pathway is the formation of imidazole and N-methylimidazole with concomitant dealkylation. The cleaved-off alkyl groups, apparently in cationic form, react with the anions present, accounting for the formation of alkyl chlorides and alkyl acetates from the chloride ILs and acetate ILs, respectively. A second, minor pathway comprises the degradation of the imidazole ring under conversion of the C2-unit from the former C4-C5 moiety into ethylenediamine and reaction of the C1-unit from the former C2 with the IL anions. Because of the non-neglible byproduct formation, the degradation of the ILs upon beta-irradiation and possible side reactions of the resulting byproducts need to be kept in mind for all setups that involve beta-irradiation and imidazolium ILs simultaneously. Graphical abstract

UV-Radiation and TiO2 Nanoparticles Effects on Physical Properties of PVA/CMC/TiO2 Nanocomposite Films

Fabrication of nanocomposite films of polyvinyl alcohol/carboxymethyl cellulose (PVA/CMC) blended with Titanium dioxide nanoparticles (TiO2 NPs) by a modest solution casting technique is investigated. Also, TiO2 NPs and UV-irradiation effects for different intervals (12, 26, 40, and 48 hours) on the morphology (FESEM), structure (XRD), composition (FTIR) and optical properties (UV-Vis) of as-prepared films are inspected. FESEM images display that the morphology of PVA/CMC/TiO2 nanocomposite films is altered due to the strong influence of TiO2 NPs and UV exposure. The XRD spectra indicate that the amorphous phase of the samples has changed (decline or enhancement) due to UV exposure. The FTIR spectra demonstrate that the UV-irradiation period had a favourable impact on polymer structure by exhibiting some interesting IR peaks. Furthermore, the UV-Vis examination illustrates that the increased UV-irradiation times (12 h to 40 h) and TiO2 NPs addition improved the absorption intensity of the as-prepared films. Interestingly, the Energy gap Eg of the nanocomposite films was tuned from 4.47 eV to 5.01 eV with increased irradiation time (12 h to 40 h). In contrast, due to a higher increased UV-irradiation time of 48 h, the Energy gap Eg value of nanocomposite film was decreased to 4.62 eV. That can be attributed to the strong effect of UV exposure, which influenced the creation of structural defects. Finally, these findings prove that the PVA/CMC/TiO2 nanocomposite films have an amazing chance to be used in important optoelectronic applications.

Evaluation of quantification methods to determine photodynamic action on mono- and dual-species bacterial biofilms.

The effect of photodynamic inactivation (PDI) sensitized by 5,10,15,20-tetra(4-N,N,N-trimethylammoniophenyl)porphyrin (TMAP4+) on different components of mono- and dual-species biofilms of Staphylococcus aureus and Escherichia coli was determined by different methods. First, the plate count technique showed that TMAP4+-PDI was more effective on S. aureus than E. coli biofilm. However, crystal violet staining revealed no significant differences between before and after PDI biofilms of both bacteria. On the other hand, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method indicated a reduction in viable cells as the light exposure time increases in both, mono- and dual-species biofilms. Furthermore, it was determined that as the irradiation time increases, the amount of extracellular polymeric substances present in the biofilms decreased. This effect was presented in both strains and in the mixed biofilm, being more evident in S. aureus mono-specie biofilm. Finally, scanning electron microscopy analysis showed a decrease in the number of cells forming the biofilm after photosensitization treatments. This information makes it possible to determine whether the photodynamic action is based on damage to metabolic activity, extracellular matrix and/or biomass, which may be useful in establishing a fully effective PDI protocol for the treatment of microorganisms growing as biofilms.

Simulation of Boron Dose and Irradiation Time in Lung Cancer Treatment with Boron Neutron Capture Therapy (BNCT) Using MCNP-6

<p>Boron Neutron Capture Therapy (BNCT) is a cancer radiation treatment. This approach employs a boron carrier agent in the form of a chemical that is injected into the body and then travels to the cancer cells. In a lung cancer case study, BNCT treatment simulation was carried out using Monte Carlo N Particle (MCNP) software version 6.2. The goal of this study was to determine the most effective boron concentration and irradiation duration in lung cancer therapy utilizing the BNCT method. The geometry based on a phantom model created by Oak Ridge National Laboratory (ORNL). The simulated cancer geometry, which is placed in the right lung's middle lobe. The skin, ribs, and right lung are among the organs at risk. The skin, ribs, and right lung are among the organs at risk. The neutron source for the simulation is the collimator output from the Kartini Nuclear Reactor's thermal column. In this simulation, the variations in boron concentrations were 40 g/g, 45 g/g, 50 g/g, 55 g/g, and 60 g/g of cancer tissue at 5 g/g intervals. The researchers discovered a link between boron injection concentration and irradiation time, with higher boron injection concentrations resulting in shorter irradiation times. The volume of boron injected determines the effective dose absorbed by healthy tissue surrounding cancer cells. The effective boron concentration for lung cancer therapy is 60 g/g, with deterministic cell killing in the rib marrow and right lung. When utilizing a boron concentration of 60 g/g, the irradiation time is 20.4 minutes. Boron concentrations of 60 g/g are projected to create an effective irradiation time for BNCT-based lung cancer therapy based on the ALARA principle due to their shorter duration when compared to other concentration variations.</p>

Effect of high irradiance and short exposure times on the depth of cure of six bulk-fill resin composites.

This study examined the effect of high irradiance and short exposure times on the depth of cure of six resin-based composites (RBCs). Bluephase PowerCure and the Valo X light-curing units (LCUs) were used to photocure bulk-fill RBCs for their recommended exposure times: Admira Fusion x-tra (AFX/20s), Aura Bulk Fill (ABF/20s), Filtek One Bulk Fill (FOB/20s), Opus Bulk Fill APS (OBF/30s), Tetric EvoCeram Bulk Fill (TEC/10s) and Tetric PowerFill (TPF/10s). In addition, all bulk-fill RBCs were tested for depth of cure with one short 3 s exposure time from the Bluephase PowerCure or the Valo X in the Xtra Power mode. The RBCs (n=10 per RBC) were inserted into a 4mm diameter metal mold and covered by a polyester strip before being photocured. After 24h of storage, uncured RBC was scraped away to determine the depth of cure of the RBCs. None of the RBCs achieved a 4mm depth of cure. The depth of cure of TEC and TPF was unaffected by the exposure times (recommended or short) when using the Valo X. The depth of cure of AFX/20s, AFX/Xtra Power, ABF/Xtra Power, FOB/Xtra Power, and OBF/30s RBCs was greater when using Valo X compared to the Bluephase PowerCure. It was concluded that short exposure times can reduce depth of cure and should only be used for some RBCs.

High-Efficiency Ternary CeO2/WO3/AC Photocatalyst Supported by Biomass Waste-derived Activated Carbon for Efficient Doxycycline Photodegradation: Optimization of Synthesis Conditions and Operational Parameters

Herein, a stable and reusable photocatalyst based on activated carbon (AC) with varying CeO2/WO3 loadings is synthesized and optimized using Central Composite Design (CCD) with the intention of Doxycycline (DOX) degrading as an organic pollutant. Prepared optimum photocatalyst have been characterized through XRD, BET, FE-SEM, EDS-Mapping, TEM, FT-IR, and UV-Vis band gap analyses. Additionally, the effect of operational parameters including catalyst dosage (0.2-1.4 g.L−1), DOX concentration (10-50 ppm), irradiation time (20-140 min), and pH (2-10) on DOX degradation is investigated by CCD in order to highly-efficient DOX degradation. The best working condition shows an experimental degradation efficiency of 97.23%. Moreover, selected CeO2/WO3/AC photocatalyst remove 83.11% of COD from DOX solution. The h+ and •O2− radicals are found to be essential for the destruction of the DOX due to heir strong and nonselective oxidation characteristics. Furthermore, the stability of the selected photocatalyst observed after undergoing five degradation cycles.

Photocatalytic activity and mechanism of YMnO3/NiO photocatalyst for the degradation of oil and gas field wastewater

One-step hydrothermal method has been used to synthesize YMnO3@NiO (YMO@NO) photocatalysts with high photocatalytic activity for the degradation of oil and gas field wastewater under simulated solar irradiation. Through various characterization methods, it has been confirmed that the YMO@NO photocatalyst comprises only YMO and NO, without any other impurities. The microstructure characterization confirmed that the YMO@NO photocatalyst was composed of large squares and fine particles, and heterojunction was formed at the interface of YMO and NO. The optical properties confirm that the YMO@NO photocatalyst has high UV-vis optical absorption coefficient, suggesting that it has high UV-vis photocatalytic activity. Taking oil and gas field wastewater as degradation object, YMO@NO photocatalyst showed the highest photocatalytic activity (98%) when the catalyst content was 1.5 g/L, the mass percentage of NO was 3%, and the irradiation time was 60 min. Capture and stability experiments confirm that the YMO@NO photocatalyst is recyclable and electrons, holes, hydroxyl radicals and superoxide radicals play major roles in the photocatalysis process. Based on experiments and theoretical calculations, a reasonable photocatalytic mechanism of the YMO@NO photocatalyst is proposed.

Reduction of Graphene Oxide Film on Glass Substrate using Argon Ion Beam Irradiation: A Systematic Study with X-ray Photoelectron Spectroscopy Analysis

In our research, we explored a novel and eco-friendly method of utilizing argon ion beam irradiation to thin down graphene oxide (GO) films on glass substrates, aiming to enhance their mechanical, electrical, and optical properties. By employing high-energy argon ions, we developed a groundbreaking, environmentally conscious technique that not only permits micro-patterning directly on GO films but also facilitates concurrent material characterization. Varying the energy levels (1000, 2000, and 3000 eV) and exposure times (0 to 80 sec, in 20-second increments), we meticulously examined the impact on carbon and oxygen atomic ratios of the GO using X-ray photoelectron spectroscopy (XPS) for in-depth analysis. Our findings revealed that increasing the argon ion beam energy to 2000 eV and extending the irradiation time significantly reduced oxygen content while increasing the carbon atomic ratio, indicating effective GO surface reduction. However, further increasing the energy to 3000 eV resulted in a slight increase in oxygen content and a decrease in the carbon atomic ratio compared to the energy 2000 eV, suggesting a decrease in reduction efficacy. This method's simplicity, eco-friendliness, and precision mark a significant advancement over traditional chemical reduction methods, offering a solid understanding of high-energy argon ion beam irradiation's effectiveness in GO reduction. Our comprehensive analysis, including survey and high-resolution C 1s and O 1s XPS spectra, highlights the surface chemistry modifications induced by this treatment, demonstrating the versatility of argon ion beam irradiation in producing reduced graphene oxide (rGO) for various applications.

Development of reversibly photo-crosslinkable water-stable poly(2-ethyl-2-oxazoline) nanofibers via functionalization with cinnamoyl moieties

Poly(2-ethyl-2-oxazoline) (PEtOx) is a potent member of the versatile poly(2-oxazoline) polymer platform with its high hydrophilicity that could be beneficial in numerous biomedical applications, especially in the form of a nanofibrous membrane. However, its water-solubility limits its application in situations where a stable, nanofibrous morphology is required in aqueous environments. The present work offers a straightforward route towards water-stable PEtOx-based nanofibrous membranes, via post-polymerization functionalization with cinnamoyl moieties (PEtOx-Cin) and photo-crosslinking of the electrospun membranes. It is shown that a UVB treatment does not significantly affect the nanofibrous morphology, while successfully inducing the cinnamoyl dimerization process and hence the formation of a polymeric network, as evidenced by spectral analysis. The hereby crosslinked PEtOx-based nanofibers exhibit a prolonged water-stability (at least 45 days), while, interestingly, intermediate irradiation times yield the best results. Full disintegration of the photo-crosslinked nanofibers in aqueous media could be achieved by subsequent UVC exposure. This is not only due to decrosslinking of the cinnamoyl dimers, but also due to partial degradation of the polymeric backbone. The investigation of UVB/UVC exposure on pure PEtOx nanofibrous membranes confirmed the photo-degradation of the polymeric backbone by a significant decrease in molar mass as observed by size exclusion chromatography and supported by spectral analysis. The hereby proposed, straightforward route for reversible crosslinking of PEtOx-based nanofibrous membranes and their accessible disintegration will contribute to the promotion of these materials in biomedical applications where a water-stable, nanofibrous morphology combined with high hydrophilicity and easy removal is required.

Natural Phytochemical and Visible Light at Different Wavelengths Show Synergistic Antibacterial Activity against Staphylococcus aureus

As the risk of antibiotic-resistant bacteria increases, interest in non-antibiotic treatment is also increasing. Among the methods used in non-antibiotic therapy, natural antibiotics such as essential oils have disadvantages such as low efficiency. In the case of phototherapy, the light used for antibacterial activities has low penetration into the human body because of its short wavelength, making it of low medical utility. To solve this problem, this study aimed to determine conditions for enhancing the antibacterial activity of natural phytochemicals and visible light. Four natural phytochemical extracts that showed high antibacterial properties in previous studies were analyzed. Synergistic effects on antibacterial activity and cytotoxicity were determined when natural phytochemical extracts and visible light were simultaneously used. As a result, it was confirmed that the antibacterial activity increased by four times when Sanguisorba officinalis L. was irradiated with 465 nm for 10 min and 520 nm for 40 min, and Uncaria gambir Roxb. was irradiated with 465 nm for 10 min and 520 nm for 60 min compared to when Sanguisorba officinalis L. and Uncaria gambir Roxb. were used alone. The synergistic effect on antibacterial activity was independent of the absorption peak of the natural phytochemical extracts. In addition, in the case of natural phytochemical extracts with improved antibacterial activity, it was confirmed that the improvement of antibacterial activity was increased in inverse proportion to the light irradiation wavelength and in proportion to the light irradiation time. The antibacterial activity was enhanced regardless of antibiotic resistance. In the case of cytotoxicity, it was confirmed that there was no toxicity to A549 cells when treated with 465 nm, the shortest wavelength among the natural phytochemical extracts. These results show how to replace blue light, which has been underutilized due to its low transmittance and cytotoxicity. They also demonstrate the high medical potential of using natural phytochemical and visible light as a combination therapy.

Studies on Selective Laser Quenching by High Repetition Frequency Lasers with Scanning Galvanometer

This study introduces a novel material processing methodology termed High Repetition Frequency Selective Laser Quenching (HRF-SLQ). This technique utilizes high-power lasers with a maximum power of 5 kilowatts in conjunction with a scanning galvanometer, operating at elevated repetition rates up to 200 hertz, to specifically treat surfaces of high and medium carbon steels. The application of this method leads to the creation of allotropic metal matrix composite materials (A-MMCs). In general, the scanning speed of a galvanometer can range from hundreds to thousands of times per second. Based on the high acceleration and rapid jumping characteristics of the scanning galvanometer, this technology transforms the high-power laser heating of metal plates from continuous heating mode to parallel pulse heating mode, which repeats heating 30 to 200 times per second. This transformation ensures the quenched layer avoids melting even under prolonged irradiation times by high-power lasers. Consequently, it can significantly enhance processing efficiency by selective laser quenching (SLQ), ensuring that the depth of the hardened layer reaches 0.88 to 0.94 millimeters and keeping the surface smooth without melting. This paper systematically investigates the influence of various processing parameters, such as laser power (P), single heating time (t1), and the number of processing units (N), on the depth of the SLQ and the quenching efficiency. It also examines the impact of HRF-SLQ technology on the properties of A-MMCs and analyzes temperature field variations from room temperature to melting point through simulation methods combined with laser quenching experiments.

The dazzling/damage mechanism of InGaAs detectors by near-infrared continuous laser

To investigate the dazzling/damage mechanism of InGaAs detectors by continuous laser, InGaAs detectors irradiated by continuous laser were analyzed theoretically and verified experimentally. Constructing the dazzling model of InGaAs detectors, saturated pixel data at different power levels were obtained. After comparing these data with verified experiments, it was observed that the magnitude and regularity of saturated pixel were relatively consistent at the same power levels. A finite element theoretical model of laser-irradiated InGaAs detectors was designed by Comsol. After calculation, the corresponding laser damage threshold for InGaAs detector was about 9.13 × 105 W/cm2 and 2.63 × 105 W/cm2 for irradiation times of 40 ms and 400 ms, respectively. These values were in relatively good agreement with the experimentally obtained damage thresholds of 1.07 × 106 W/cm2 and 3.95 × 105 W/cm2. The verified experiments confirmed the validity of the simulation methods and the dazzling/damage model employed in this paper. This study serves as a reference for further research on the laser irradiation effects and damage mechanisms of InGaAs detectors, as well as for laser protection and performance optimization in imaging systems.

The bacteriostatic effect of a new controlled-release carotenoids-silver nanoparticle

Discuss the bacteriostatic effect of a novel controlled release silver nanoparticles carotenoids-silver nanoparticle. Detect the optimal extraction conditions for carotenoids through material liquid ratio, different ultrasonic temperatures and times; Detect the optimal synthesis conditions of carotenoids-silver nanoparticle through different volume ratios, UV irradiation times, and temperatures; Detect the bacteriostatic effects on Escherichia coli and Staphylococcus albus using the minimum inhibitory concentration (MIC) and Oxford cup agar plate diffusion method. The experiment proved that the best extraction effect of carotenoids was achieved when the volume ratio of orange peel powder to ethanol was 1:25, the ultrasound time was 40 min, and the temperature was 50 °C; When the amount of carotenoid extract added is 12 mL, the concentration of silver nitrate is 8 mmol/l, the UV irradiation time is 40 min, and the ultrasound temperature is 60 °C, the synthesized carotenoids-silver nanoparticle has the highest absorbance value; carotenoids-silver nanoparticle have strong inhibitory effects on the growth of both Escherichia coli and Staphylococcus albus. As the concentration increases, the bacteriostatic effect also becomes stronger, especially the strongest inhibitory effect on Staphylococcus albus. It was shown that carotenoids-silver nanoparticle has significant bacteriostatic effects, providing new ideas for the development of bacteriostatic agents in plant resources.