Search Results (230)

Large-field-of-view (FOV) and high-resolution imaging have always been the goals pursued by imaging technology. A scale-adaptive high-resolution imaging architecture is established using a rotating-prism-embedded variable-boresight camera. By planning to prism motion, the multi-view images with rich information are combined to form a large-scale FOV image. The boresight is guided towards the region of interest (ROI) in the combined FOV to reconstruct super-resolution (SR) images with the desired information. A novel distortion correction method is proposed using virtual symmetrical prisms with rotation angles that are complementary. Based on light reverse tracing, the dispersion induced by monochromatic lights with different refractive indices can be eliminated by accurate pixel-level position compensation. For resolution enhancement, we provide a new scheme for SR imaging consisting of the residual removal network and information enhancement network by multi-view image fusion. The experiments show that the proposed architecture can achieve both large-FOV scene imaging for situational awareness and SR ROI display to acquire details, effectively perform distortion and dispersion correction, and alleviate the occlusion to a certain extent. It also provides higher image clarity compared to the traditional SR methods and overcomes the problem of balancing large-scale imaging and high-resolution imaging. Full article

Plant seedlings are sensitive to cultivation environment factors and highly susceptible to pathogenic infections under adverse conditions such as inappropriate light environment. In this study, five kinds of LED lighting sources with different red (R) and blue (B) light combinations were set up: R10B0, R7B3, R5B5, R2B8 and R0B10 (with R:B ratios of 10:0, 7:3, 5:5, 2:8 and 0:10, respectively) to explore their effects on tomato seedlings’ growth, AsA-GSH cycle, endogenous hormones, and resistance to Phytophthora infestans, providing a basis for factory seedling light-quality selection. The results showed that with the increase in the proportion of blue light in the composite light, the growth indicators, photosynthetic characteristic parameters and enzyme activities of tomato seedlings generally increased. The contents of AsA, reduced glutathione, and oxidized glutathione all reached the maximum under high-proportion blue-light treatments (R2B8 and R0B10). The high-blue-light groups (R2B8 and R0B10) had the highest AsA and glutathione contents. The red–blue combinations reduced inhibitory ABA and increased growth-promoting hormones (e.g., melatonin), while monochromatic light increased ABA to inhibit growth. After inoculation with P. infestans, the apoplastic glucose content was the highest under the red–blue-combined treatments (R5B5 and R2B8), while the total glucose content in leaves was the highest under the combined light R2B8 treatment. In conclusion, high-proportion blue-light treatment can greatly promote the photosynthetic process of tomato, enhance the AsA-GSH cycle, and achieve the best effect in improving the resistance of tomatoes to P. infestans. Given these, the optimal light environment setting was R:B = 2:8. Full article

In recent years, with the continuous advancement of technology and the expansion of application scenarios, AR has become a highly regarded field. However, AR still faces several challenges in practical usage. Notable shortcomings include inadequate image uniformity, low diffraction efficiency. Among these, the insufficient image uniformity stands out as a significant issue directly affecting user experience. The analysis of uniformity improvement in this study is limited to the simulated scenario of monochromatic blue light (LED light source), aiming to optimize the insufficient uniformity of the image output of the diffractive optical waveguide-based AR technology scheme. We improve the details of the input grating in the waveguide, such as the morphological characteristics of the grating, the detail parameter, etc. In addition, we propose to incorporate a photonic crystal film in the waveguide as an innovative study and find that the incorporation of the photonic crystal thin film significantly improves the uniformity of the output image in the diffractive optical waveguide scheme. In order to further verify the effect of the photonic crystal film on the uniformity of its image output, we also compare different types of coupled gratings and find that they all have a positive effect. Thus, the photonic crystal film demonstrated effective control over the diffraction optical waveguide scheme. This research offers new insights and design approaches for enhancing the output image uniformity based on diffraction optical waveguide technology, providing a new path for improving image uniformity in AR displays. Full article

Light from fast radio bursts (FRBs) can be deflected by the gravitational lensing effect of primordial black holes (PBHs), if they are distributed along the path from the FRBs to the observer. Consequently, the PBH mass function can be constrained by the lensing events of FRBs. In this work, four different PBH mass functions are investigated (i.e., the monochromatic, log-normal, skew log-normal, and power-law distributions), and the constraints on the model parameters are obtained, if the PBH abundance $f_{\mathrm{PBH}}$ and the event rate of lensed FRBs $\overline{\mathit{\tau }}$ are given. We find that, if $\overline{\mathit{\tau }}<{10}^{-4}$ in future FRB experiments, $f_{\mathrm{PBH}}$ will be less than ${10}^{-2.5}$ in most of the PBH mass range from 1–$100M_{\odot }$ for the monochromatic mass function. Moreover, for the three extended mass functions, $\overline{\mathit{\tau }}$ increases when the PBH mass distributions spread to larger masses, setting more stringent constraints on $f_{\mathrm{PBH}}$. Full article

Neutrophils are the first line of defense of the human immune system against pathogens. Photobiomodulation, mediated by mitochondrial photoacceptors such as cytochrome c oxidase, has emerged as a method to modulate neutrophil function through targeted light exposure. Despite the extensive characterization of neutrophil extracellular traps (NETs) formation (NETosis), the wavelength-specific modulation of neutrophil photoactivation and the involvement of redox pathways remain poorly defined. In this study, the effects of monochromatic (365 nm, 415 nm, 437 nm, and 625 nm) and dichromatic LED-light irradiation on NETs formation were systematically examined. The highest netotic responses were elicited by UV-A (365 nm) and violet-blue light (415 nm), whereas 437 nm showed the lowest induction and 625 nm stimulated a moderate netotic response. The pharmacological inhibition of NETosis induced by 365 nm and 415 nm irradiation with specific NADPH oxidase inhibitor, apocynin, and mitochondrial reactive oxygen species (mtROS) scavenger, MitoTEMPO, attenuated NETs formation by engaging both enzymatic and mitochondrial oxidative sources. Notably, mtROS played a dominant role under 415 nm stimulation in contrast to 365 nm-induced NETosis as demonstrated by higher sensitivity to MitoTEMPO. Importantly, combined simultaneous irradiation with 415 nm and 625 nm LEDs resulted in a significant suppression of NETs formation by more than 50%, highlighting a potent inhibitory synergy observed for the first time and suggesting a new approach of wavelength pairing to modulate neutrophil activation. These results were further supported by measurements of ROS production using a luminol-amplified chemiluminescence assay. Collectively, these findings delineate a wavelength- and ROS-dependent framework for light-induced neutrophil activation, with mitochondrial pathways exerting central control particularly under short-wavelength irradiation. Full article

The current research on light transmission under rainfall conditions primarily focuses on monochromatic converging light sources, and the related conclusions cannot be directly applied to spherical continuous-spectrum light sources (SCLSs). Based on the Lorenz–Mie scattering method, this study calculated the optical parameters of Gamma-distributed rainfall across three rainfall types and four intensity levels. A numerical algorithm model for radiative transfer under rainfall conditions was established for SCLSs. The effects of rainfall type, rainfall intensity, and light wavelength on radiative transfer were analyzed. Key conclusions include the following: when rainfall intensity is below moderate, the type of rainfall can be disregarded. However, for heavy to torrential rain, distinct differences between stratiform and non-stratiform rainfall must be considered. The attenuation caused by rainfall intensity does not increase linearly. Specifically, attenuation during moderate rain is lower than that in light rain, while heavy and torrential rain exhibit greater attenuation than both light and moderate rain. Wavelength bands significantly influence radiative transfer. Efforts to optimize the attenuation of radiative energy by rainfall should focus on the primary energy bands where most energy is concentrated. These findings highlight the importance of considering rainfall classification, nonlinear attenuation mechanisms, and wavelength-specific characteristics when evaluating radiative transfer under varying rainfall conditions. Full article

It is well known that for low-intensity incident light within a certain frequency range, the stopping voltage of the photoelectric effect is independent of the intensity but dependent on the frequency of the light, which is described by the equation $V=h\nu /e-W_0/e$, where V is the stopping voltage, h is the Planck constant, $\nu$ is the frequency of incident light, e is the basic charge, and $W_0$ is the work function. This implies that the stopping voltage increases with the frequency of the incident light. However, our experiments reveal that for non-monochromatic incident light, the stopping voltage is not determined by the maximum frequency component of the incident light, but by the maximum center frequency among all wave train components (with different center frequencies) involved in the incident light; that is to say, in the photon energy expression $h\nu$, the physical quantity $\nu$ does not refer to the frequency of monochromatic light, but represents the center frequency of a wave train spectrum. The spectral bandwidth of a wave train component can be as large as 122 nm in the visible and near-infrared regions. These findings highlight the need for greater attention to such effects in photoelectric detection and the study of energy exchange between light and matter. Full article

Light is a major environmental factor that regulates circadian rhythms and pineal melatonin synthesis. While the influence of nighttime light exposure on melatonin suppression has been extensively investigated, much less is known about the impact of photophase light wavelength on pineal function. The aim of the study was to determine the influence of monochromatic light during the photophase on diurnal changes in melatonin-related indoles in the rat pineal gland. Wistar rats were exposed for 7 days to 150 lx of monochromatic blue (463 ± 10 nm), green (523 ± 10 nm), or red (623 ± 10 nm) LED light, or to white fluorescent light (control), under a 12:12 light–dark cycle. Pineal glands were collected every 3 h over 24 h, and the indole content was analyzed by high-performance liquid chromatography. The results demonstrated that both the timing and course of N-acetylserotonin (NAS) and melatonin (MLT) rhythms were significantly affected by light wavelength. Blue light most effectively preserved the normal rhythmicity observed under full-spectrum white light, whereas green—and particularly red light—delayed nocturnal NAS and MLT synthesis. These changes were accompanied by concurrent alternations in rhythms of serotonin, its precursors, and metabolites. The data strongly suggest that spectral light composition during the photophase influences pineal indole metabolism via melanopsin-mediated phototransduction and possibly other retinal mechanisms. These findings may have implications for the design of artificial lighting environments in human life and animal housing. Full article

When a semiconducting sample is illuminated by an intensity-modulated monochromatic light beam with photon energy exceeding the band gap, part of the absorbed energy is directly converted into heat through photon–lattice interactions. This gives rise to a heat source that closely follows the temporal profile of the optical excitation, known as the fast heat source. Simultaneously, another portion of the absorbed energy is used to generate electron-hole pairs. These charge carriers diffuse together and recombine via electron–electron and electron–hole interactions, transferring their kinetic energy to the lattice and producing additional heating of the sample. This indirect heating mechanism, associated with carrier recombination, is referred to as the slow heat source. In this study, we develop a model describing surface temperature variations on the non-illuminated side of a thermally thin semiconductor exposed to a rectangular optical pulse, explicitly accounting for the contribution of surface charge carrier recombinations. Using this model, we investigate the influence of surface recombination velocity and the material’s plasma properties on the time-domain temperature response for both plasma-opaque and plasma-transparent samples. Our results demonstrate that charge carrier recombinations can significantly affect the transient photoacoustic signal recorded using a minimum volume cell, highlighting the potential of time-resolved photoacoustic techniques for probing the electronic properties of semiconductors. Full article

In this study, the effects of different monochromatic (red, blue, and yellow light) and composite (red–blue and red–yellow) LED light withering on the aroma of black tea was investigated. The results showed that among monochromatic LED treatments, red light withering achieved the highest sensory evaluation score for aroma. However, yellow light withering enhanced soluble sugar content and reduced tea polyphenol levels. It also increased the total amount of volatile compounds more effectively than red or blue light treatments. Nevertheless, single-wavelength LED withering was less effective than natural light in aroma improvement. In contrast, composite light withering outperformed single-wavelength LED treatments in improving black tea aroma, with the red–yellow light combination being more pronounced. It elevated the level of hydrocarbons, certain aldehydes, and alcohols, which ultimately impart an almond-like and roasted aroma profile to the black tea. The findings suggested that appropriate composite light withering can effectively improve the aroma of black tea. Full article

This study investigates the effect of monochromatic light on the body weight (BW), melatonin concentration and its receptors expression levels, intestinal health, and gut microorganisms of Yangzhou geese. Green light (GL) significantly increased BW, melatonin and its receptor expression levels, villus height (VH) and villus height/crypt depth (VH/CD) ratio, superoxide dismutase (SOD), catalase (CAT), and total antioxidant capacity (T-AOC) activities, as well as the abundance of Synergistota and Prevotellaceae_UCG-001, compared with white light (WL). Blue light (BL) significantly increased the mRNA expression of melatonin membrane receptor 1a (Mel1a) and nuclear receptor 1α (RORα), VH and VH/CD ratio, CAT activity, cecal microbes diversity, and decreased malondialdehyde (MDA) levels. Red light (RL) significantly decreased average daily feed intake, reduced the abundances of Synergistota and Prevotellaceae_UCG-001, and increased Mel1a and RORα mRNA expression levels, MDA content, and cecum microbial diversity. Moreover, melatonin levels were significantly higher in the GL and BL groups compared to RL. Furthermore, the mRNA expression levels of Claudin-10, Occludin, and occludens-1 (ZO-1) were significantly upregulated under GL or BL exposures compared to the WL group, whereas RL only enhanced the expression levels of ZO-1. Spearman’s correlation analysis revealed that the relative abundance of Prevotellaceae_UCG-001 exhibited positive correlations with BW, melatonin and its receptors expression, gut health, and antioxidant capacity. Overall, these findings suggested that GL exposure enhanced melatonin synthesis and its receptors expression, modulated intestinal homeostasis and microbial ecology, and ultimately increased goose BW. Full article

Synchrotron radiation light sources have been successfully utilized in material science, biomedicine, and other fields due to their high intensity, excellent monochromaticity, coherence, and collimation. In recent years, synchrotron radiation has significantly expedited the advancement of medical applications, particularly through innovations in imaging and radiotherapy. For instance, synchrotron X-ray imaging has enabled high-contrast and spatial–temporal resolution images for early-stage diagnosis of breast cancer and cardiovascular diseases, offering superior diagnostic accuracy compared to conventional methods. Additionally, novel synchrotron radiation-based radiotherapy techniques, such as microbeam therapy and stereotactic radiotherapy, have shown great potential for clinical application by enabling precise tumor targeting while minimizing damage to surrounding healthy tissues. These advancements are projected to redefine imaging diagnostics and therapeutic strategies, particularly for resistant cancers, by offering enhanced precision, reduced radiation doses, and improved therapeutic outcomes. This review provides an overview of synchrotron radiation beamline characteristics, recent breakthroughs in imaging and radiotherapy, and their emerging applications in treating heart, breast, lung, bone, and brain conditions. Full article

When interferograms in space heterodyne spectrometers exhibit tilted or distorted fringes, significant errors may occur in the demodulated spectral information. To address this issue, we propose a method for interferogram correction based on automatic spectral analysis. Simulations on erroneous interferograms of monochromatic and polychromatic light demonstrate that this method effectively corrects fringe tilts and significantly improves spectral demodulation accuracy. The standard deviations between the corrected spectra and ideal spectra for monochromatic and polychromatic light are 0.016 and 0.019, respectively, compared to 0.104 and 0.127 for uncorrected spectra. Additionally, the method successfully corrects experimental interferograms of potassium and neon lamps, accurately demodulating characteristic peaks of potassium and neon emission lines. It also enables accurate displacement measurement in a Michelson interferometer experiment. This method, through automatic analysis and one-sided spectral correction, efficiently and accurately corrects erroneous interferograms and enhances spectral demodulation accuracy, showing broad application potential. Full article

The genus Trichoderma comprises a group of fungi known for their beneficial effects on plant growth and stress tolerance. Light is a key environmental factor affecting many plant physiological processes. However, a significant research gap remains regarding the interaction between light quality and Trichoderma harzianum inoculation, particularly their combined effects on tomato plant growth and photosynthetic efficiency. Here, we showed that T. harzianum inoculation effectively alleviated the growth inhibition caused by monochromatic red light or blue light in tomato plants. Combined red and blue light treatment with T. harzianum inoculation (RBT) promoted root development by regulating the rational distribution of carbon assimilation products. Specifically, the RBT treatment upregulated the expression of photosynthesis-related genes, including key Calvin cycle enzyme genes such as FBPase, FBPA, TPI, and SBPase, as well as the light signal transduction factor HY5. In addition, T. harzianum inoculation increased the maximal photochemical efficiency of PSII (Fv/Fm), and the net photosynthetic rate (Pn). The activity of sucrose synthetase (SS) and sucrose phosphate synthetase (SPS) was also enhanced, promoting photosynthetic product accumulation in leaves and roots. Among all treatment groups, RBT performed the best in the above indexes. Full article

Light is crucial in controlled-environment agriculture (CEA), affecting germination, growth, and overall plant quality. Here, we explored the optimization of various LED light spectra on the germination traits such as germination percentage, mean germination time, germination index, vigor index, and early seedling growth of ‘Lollo Bionda’ lettuce seedlings in a plant factory. A completely randomized design was implemented, involving three replications. LED lamps with different spectral compositions—red (R, peak at 656 nm), red/blue (3:1 ratio, R:B, peak at 656 nm), blue (B, peak at 450 nm), and white (400–700 nm)—were utilized in this study. The combination of red and blue LED lights, along with monochromatic red and blue treatments, significantly enhanced germination traits and early seedling growth compared to white and ambient lighting. The combined spectrum resulted in the highest seedling emergence, the longest shoot and root lengths, and the highest fresh weight. These findings underscore the potential of the LED technology to improve germination efficiency and enhance seedling quality in CEA. Future studies should refine multispectral LED strategies by examining factors such as light intensity and photoperiod, while also elucidating the molecular pathways involved in light-driven germination and early development in lettuce. Full article