Refraction Of Light Research Articles

Tailoring anisotropic ZnO/wood-structural holocellulose hybrids for dye degradation through controlled nanoinsertion

Nanostructured inorganic/wood-structural holocellulose hybrids offer new potential applications, including mechanical energy conversion, superhydrophobic materials, gas adsorption and so on. Owing to the anisotropy of wood, controlling the morphology of mineral particles inside porous holocellulose scaffold is still far from satisfactory. In this work, a homogeneous zinc oxide (ZnO) decoration inside wood-structural holocellulose scaffold was achieved while the morphology, distribution and content of ZnO micro-nano particles were controllable through changing the conditions of hydrothermal growth. The holocellulose scaffold was prepared through delignification and periodate oxidation, which is favorable for Zn2+ capture and ZnO nuclei formation because of the surface charge increased. The controlled ZnO insertion was realized by changing metal salt concentration, temperature and hydrothermal time. The obtained multilayer ZnO could provide multiple light refractions and reflections and enhance the utilization of light. Consequently, with a minor ZnO loading (15 wt%), the ZnO/wood-structural hybrids could totally degrade methyl orange and methyl blue in 6 h. This novel and scalable synthesis method shows potential for both the design and photocatalytic activity of holocellulose hybrids.

Ultraviolet optical properties of CaSrF2 crystal grown by the cone die Czochralski method

Fluoride crystals with extremely wide band gaps are ideal optical materials in the UV wavelength range. Large 4-inch diameter calcium strontium fluoride (Ca0.582Sr0.418F2) single crystal was grown using the Czochralski method with a Cone-shape Die (CD-CZ). The refractive index and relative transmittance of the crystal was evaluated by cutting it into a triangular prism and polished. The direct measurement of the refractive index and relative transmittance was done by using a spectrograph to image the refraction of light as it passes through a dual prism set-up consisting of a SQ prism as reference and either CaF2 or Ca0.582Sr0.418F2 as the material under evaluation. Characterization results showed that Ca0.582Sr0.418F2 has excellent refractive index dispersion and transmittance in the UV region, confirming the applicability of the dual prism with spectrograph setup to measurements of the refractive index and relative transmittance in the UV region.

Paper Crystallisations

Abstract This essay investigates the graphical and diagrammatic techniques the Dutch mathematician and natural philosopher Christiaan Huygens (1629–1695) employs in his meteorological investigations. A distinction is discerned between Huygens’ drawings of crystalline structures under the microscope, and his hypothetical modelling of different types of atmospheric light-refracting bodies. It is demonstrated, however, that both domains of inquiry are intricately connected through Huygens’ longstanding interest in “wondrous” light refraction phenomena in the atmosphere, such as solar halos and parhelia.

3D-3C measurements of flow reversal in small sessile drops in shear flow

Sessile drops play an important role in nature and the operation of many technical and biological systems as for instance fuel cells, cleaning processes, lab-on-a-chip devices and single-cell analysis. Nonetheless, their dynamic behaviour in a shear flow is still not fully understood (e. g. detachment mechanism). Challenges exist regarding the precise simulation of two-phase flows as well as difficulties in conducting flow measurements with sufficient temporal resolution of more than 1 kHz. In this article, we present the first three-dimensional flow measurements in strongly oscillating drops stemming from a shear flow by using a monocular 3D localization microscope based on a Double-Helix Point Spread Function combined with Particle Tracking Velocimetry. The high temporal resolution and the large measurement volume - in terms of microscopy - make it possible to measure the time- and phase-averaged flow in small drops with Bond numbers (Bo) smaller than 1. Water drops were placed in an air flow channel and measurements were conducted for Reynolds numbers (Red) from about 750 to 1700. Our measurements show that the results of previous investigations for drops with Bo>1 concerning vortex pattern and flow reversal inside the drop apply for smaller drops as well. In addition, we are able to reveal the three-dimensional flow structure and multiple vortex-pattern in time and space. We discover a periodic 3D vortical flow pattern that corresponds to the first and second eigenfrequency of the drop. Moreover, we demonstrate the potential of adaptive optics to correct measurement errors stemming from time-varying light refraction when conducting measurements through the fluctuating drop surface, in particular for opaque substrates. The results may help in understanding the coupling of inner and outer flow for sessile drops in shear flow which allows for an analysis of the onset motion of these drops, i.e. drop removal. Removal of sessile drops plays a crucial role in many applications, which includes among other things the water management of fuel cells where small drops with Bo<1 predominantly occur.

Nanofiber aerogel with layered array with structure coupled photothermal/magnetothermal effect for continuous seawater desalination

The solar evaporation is susceptible to intermittent solar irradiation as well as salt crystallization deposition on the surface severely limits the evaporation efficiency. In this work, subject to inspiration of the transpiration, groove array structure and antifouling performance of banana leaves, a multifunctional photothermal/ magnetothermal coupled three-dimensional(3D) aerogel evaporator with layer-by-layer array structure was prepared by blow-spun technology which can achieve mass produced. The unique super hydrophilic vertical array structure has multi-scale high-efficiency water transport channels and the SnSe-Fe3O4 evaporation layer realizes super hydrophobic self-cleaning and excellent photothermal and magnetothermal conversion performance, which can achieve all-weather seawater desalination. The vertical array structures facilitate the reflection and refraction of light and promote the seawater convection and salt crystals absorption coupling. It could improve the photothermal conversion efficiency and salt resistance of the evaporator. Which resulted in an evaporation rate of 2.53 kg m−2h−1 under 1 sun, with solar energy conversion efficiency of 105 % and the evaporation rate is about 4.54 kg m−2h−1 at a magnetic field. Furthermore, it could purify organic pollutants in industrial wastewater and use waste heat to generate electricity. This evaporator provides a new economical and environmentally friendly solution for seawater desalination and sewage treatment.

RSE-YOLOv8: An Algorithm for Underwater Biological Target Detection.

Underwater target detection is of great significance in underwater ecological assessment and resource development. To better protect the environment and optimize the development of underwater resources, we propose a new underwater target detection model with several innovations based on the YOLOv8 framework. Firstly, the SAConv convolutional operation is introduced to redesign C2f, the core module of YOLOv8, to enhance the network's feature extraction capability for targets of different scales. Secondly, we propose the RFESEConv convolution module instead of the conventional convolution operation in neural networks to cope with the degradation of image channel information in underwater images caused by light refraction and reflection. Finally, we propose an ESPPF module to further enhance the model's multi-scale feature extraction efficiency. Simultaneously, the overall parameters of the model are reduced. Compared to the baseline model, the proposed one demonstrates superior advantages when deployed on underwater devices with limited computational resources. The experimental results show that we have achieved significant detection accuracy on the underwater dataset, with an mAP@50 of 78% and an mAP@50:95 of 43.4%. Both indicators are 2.1% higher compared to the baseline models. Additionally, the proposed model demonstrates superior performance on other datasets, showcasing its strong generalization capability and robustness. This research provides new ideas and methods for underwater target detection and holds important application value.

Treatment of antibiotics in mariculture wastewater via phosphate-doped porous coralline carbon nitride/porous mullite honeycomb sunlight-driven photocatalytic system: Morphological control, long-term and continuous flow application

Herein, this study describes a promising sunlight-driven photocatalytic system designed for the elimination of antibiotics (e.g., fluoroquinolones and sulfonamides) in real maricultural wastewater. Phosphate-doped porous coralline carbon nitride (P-CCN), synthesized by controlling morphology from two-dimensional block CN, was immobilized onto porous mullite honeycomb to construct a practical and molding photocatalytic system (P-CCN/PMH). By leveraging its microscopic porous coral structure, P-CCN displayed an augmentation in surface-active sites and a notable inner light refraction effect. This enhancement contributed to the high-efficiency performance of P-CCN/PMH system, producing 8.232 mM·h−1·g−1 H2O2 under sunlight, which was 7.21-fold higher than before modification; and its degradation rate constant to enrofloxacin (0.263 min−1) was 39.31-fold higher. The P-CCN/PMH system demonstrated superior capability in terms of adaptability to a wide concentration range, acid-alkali conditions, mineralization, carbon reduction, and challenging ionic surroundings or water matrices. Crucial superoxide radicals have been confirmed through mass-spectrometric technique and theoretical calculations, leading to ring-opening effects. Long-term and continuous-flow experiments were deeply carried out, validating the commendable competence of the P-CCN/PMH photocatalytic system in simulated wastewater treatment scenarios. Ultimately, the aggregate results highlight valuable insights into coralline materials synthesis and modular catalyst construction, presenting potential for addressing challenges related to environmental antibiotics pollution.

Bridging concepts of drishti: Shalakya tantra and modern science

Introduction: Shalakya Tantra, a key aspect of traditional Indian medicine, focuses on the intricacies of human vision or 'drishti' in Ayurvedic literature. This ancient discipline offers a comprehensive exploration of 'Urdhvajatrugata' parts, encompassing the eyes, ears, nose, throat, and head, which modern research has yet to match in depth. The study of 'drishti' and its related concepts, such as 'mandala,' 'patala,' and 'sandhi,' reveals a profound understanding that warrants further exploration, particularly in contrast with contemporary findings. The Sushruta Samhita details 'Drishti' extensively, describing its anatomical and functional aspects, including its composition of 'Dravyas' (substances) and 'Mahabhutas' (elements), with a notable presence of 'Teja' or fire as 'Alochaka Pitta.' Aim and Objective: · To describe 'Drishti' from both Ayurvedic and modern perspectives. · To provide a detailed analysis of the various aspects of 'Drishti.' Materials and Methods: Materials include Ayurvedic scriptures (Sushruta Samhita, Charak Samhita, Bhela Samhita), modern textbooks, medical journals, and published research papers. The study is a review based on literature from authentic Ayurvedic sources and modern texts. Results and Discussion: The concept of 'Drishti' is analysed from anatomical and physiological viewpoints. Ayurvedic texts describe the eye as a layered entity with six junctions and thin membranes crucial for its function. Different interpretations of 'Drishti' include the retina, vision, pupil, and crystalline lens. Modern science aligns with these descriptions through detailed processes involving light refraction, image focusing, and neural processing. Conclusion: The study highlights the synergy between Ayurvedic and modern scientific perspectives on 'Drishti,' emphasizing the relevance of traditional wisdom in contemporary healthcare. Integrating these approaches offers a richer understanding of ocular health and underscores the potential for future research to enhance medical treatments and promote holistic well-being.

Method of 3D reconstruction of underwater concrete by laser line scanning

High-precision 3D (three-dimensional) reconstruction of underwater concrete is helpful for the detection and analysis of underwater concrete diseases. A prevalent method involves mounting optical cameras in waterproof housings to enable the 3D reconstruction of underwater concrete. Achieving millimetric accuracy in underwater 3D reconstruction poses a significant challenge in current research. The refraction of light on surfaces of different media and its reflection underwater complicate the process. In this paper, a 3D reconstruction method of underwater concrete based on laser line scanning is proposed. Firstly, the underwater imaging model is established by the ray tracing method, and the refraction conversion matrix is derived. Then, based on this matrix, the conversion relationship between the measured 3D size and the real 3D size of the underwater object is obtained. Finally, image restoration technology is introduced in the process of laser stripe extraction to eliminate the influence of reflected light on the extraction of laser stripe center, to improve the reconstruction accuracy. We used the independently developed laser line 3D scanning equipment to carry out experimental analysis. The results showed that the error rate caused by direct reconstruction of underwater objects was 9.75 %. Additionally, the error rate obtained from 3D reconstruction of underwater objects using the conversion model was 2.89 %. This study provides technical support for the 3D detection of underwater concrete.

Polarization-sensitive optical coherence tomography and scleral collagen fiber orientation in osteogenesis imperfecta

Osteogenesis imperfecta (OI), a rare genetic connective tissue disorder, primarily arises from pathogenic variants affecting the production or structure of collagen type I. In addition to skeletal fragility, individuals with OI may face an increased risk of developing ophthalmic diseases. This association is believed to stem from the widespread presence of collagen type I throughout various parts of the eye. However, the precise consequences of abnormal collagen type I on different ocular tissues remain unknown. Of particular significance is the sclera, where collagen type I is abundant and crucial for maintaining the structural integrity of the eye. Recent research on healthy individuals has uncovered a unique organizational pattern of collagen fibers within the sclera, characterized by fiber arrangement in both circular and radial layers around the optic nerve head. While the precise function of this organizational pattern remains unclear, it is hypothesized to play a role in providing mechanical support to the optic nerve. The objective of this study is to investigate the impact of abnormal collagen type I on the sclera by assessing the fiber organization near the optic nerve head in individuals with OI and comparing them to healthy individuals. Collagen fiber orientation of the sclera was measured using polarization-sensitive optical coherence tomography (PS-OCT), an extension of the conventional OCT that is sensitive to materials that exhibit birefringence (axial changes in light refraction). Birefringence was quantified and used as imaging contrast to extract collagen fiber orientation as well as the thickness of the radially oriented scleral layer. Three individuals with OI, exhibiting different degrees of disease severity, were assessed and analyzed, along with seventeen healthy individuals. Mean values obtained from individuals with OI were descriptively compared to those of the healthy participant group. PS-OCT revealed a similar orientation pattern of scleral collagen fibers around the optic nerve head between OI individuals and healthy individuals. However, two OI participants exhibited reduced mean birefringence of the radially oriented scleral layer compared to the healthy participant group (OI participant 1 oculus dexter et sinister (ODS): 0.34°/μm, OI participant 2: ODS 0.26°/μm, OI participant 3: OD: 0.29°/μm, OS: 0.28°/μm, healthy participants: ODS 0.38 ± 0.05°/μm). The radially oriented scleral layer was thinner in all OI participants although within ±2 standard deviations of the mean observed in healthy individuals (OI participant 1 OD: 101 μm, OS 104 μm, OI participant 2: OD 97 μm, OS 98 μm, OI participant 3: OD: 94 μm, OS 120 μm, healthy participants: OD 122.8 ± 13.6 μm, OS 120.8 ± 15.1 μm). These findings imply abnormalities in collagen organization or composition, underscoring the necessity for additional research to comprehend the ocular phenotype in OI.

A photoelectrochemical sensor based on In2S3/AgInS2 in situ Z-type heterojunction with “photo-modulated interface charge” for sensitive detection of Programmed Death-Ligand 1

The construction of heterostructure photoelectrodes can enhance the performance of photoelectrochemical (PEC) sensors. However, it is still a critical challenge to achieve efficient transfer of interface carriers. In this paper, we propose a strategy of “photo-modulated interface charge” to design a PEC sensor based on a hollow hexagonal tubular In2S3/AgInS2 in situ Z-type heterojunction for the susceptible detection of Programmed Death-ligand 1 (PD-L1). The hollow structured In2S3/AgInS2 is ingeniously synthesized employing indium-sourced MIL-68 as a sacrificial template and in situ cation exchange technique. This composite material has close contact interfaces due to in situ growth, which facilitates the spontaneous establishment of a robust and stable built-in electric field between the interfaces. Moreover, the inner cavity structure promotes multiple light refractions and scatterings, significantly enhancing light trapping capability. Under the influence of both light irradiation and electric field force, the migration direction of the interfacial charge is reversed, forming a Z-transfer path, which effectively delays the compounding of the electron-hole pairs (e-/h+) and further improves the sensitivity of the sensor. The minimum detection threshold of the PEC sensor is 26.58 fg/mL, and the feasibility of real samples is investigated, providing new insights for early diagnosis and prognostic treatment of diseases.

Bio-Inspired Photosynthesis Platform for Enhanced NADH Conversion and L-Glutamate Synthesis.

Inspired by the layered structure, light absorption, and charge carrier pathway of chloroplast thylakoids in natural photosynthesis, we propose a novel artificial photosynthesis platform, which is composed of layered structured vaterite as the scaffold with gold nanoparticles (AuNPs), photosensitizer eosin Y (EY), and redox enzyme L-glutamate dehydrogenase (GDH) as the functional components. The EY exhibited significantly enhanced light absorption and charge carrier generation due to the localized surface plasmon resonance (LSPR) around the AuNPs and light refraction within the layers. This artificial photosynthesis platform can regenerate reduced nicotinamide adenine dinucleotide (NADH) under visible light and promote the rapid conversion of α-ketoglutarate to L-glutamate (0.453 Mm/h). The excellent biocompatibility of layered vaterite significantly enhances the resistance of GDH to harsh conditions, including high pH (pH = 10) and elevated temperatures (37-57 °C).

Comparison Subjective and Objective Chromoretinoscopy

Subjective duochrome (chromoretinoscopy) is a method of analyzing the refraction of light in the eye using a small, hand-held device called a duochrome. The device consists of a light source and two filters; one red and other is green. The light is shone into the eye, and the filters are used to measure the amount of light that is absorbed or scattered by the eye. It relies on the observations and interpretation of the person performing the test. The results of the test can be influenced by factors such as the skill and experience of the person performing the test, as well as the patient's cooperation and willingness to follow instructions. Objective duochrome (chromoretinoscopy) is a method of analyzing the refraction of light in the eye using an automated device. The device uses a light source and two filters, similar to the subjective duochrome, but it also includes a computerized system for measuring and analyzing the results. It relies on the automated measurement and analysis of the results, rather than on the observations and interpretation of the person performing the test. As a result, it is generally considered to be more accurate and reliable than subjective duochrome chromoretinoscopy. To compare retinoscopy using colored filters (chromo-retinoscopy) with the conventional subjective duochrome method. All people between the ages of 16-35 years are included in this study whose responses are reliably taken in the subjective part of this study. Emmetropic, any kind of ametropic people have included in the study. The people were excluded with variable or unreliable responses, having any ocular pathology, and tired and irritated people. The difference between subjective and objective duochrome tests is 0.006 diopters. Statistically, this is not a significant difference. The objective duochrome technique (chromoretinoscopy) yields highly correlating values to subjective duochrome values. Thus, this technique can be relied on and can be added as a part of regular workup in clinics.

Photocatalytic activity of molybdenum disulfide nanotube arrays with different wall thicknesses under visible light

Light trapping based on nanostructure has emerged as an effective method to improve light absorption of the photocatalytic devices. Herein, molybdenum disulfide nanotube arrays with different wall thicknesses were successfully synthesized by changing reactant concentration from 50 % to 150 %. The nanotubes overcame aggregation of the nanosheets, offered multiple scattering centers and enabled multiple refraction of light, leading to excellent light harvest in the visible range and molecule absorption efficiency as high as 21.0 %. The photodegradation efficiency of methylene blue as catalyzed by the nanotubes was modulated by the wall thickness, in which the highest degradation efficiency of 69.6 % and the largest kinetic constant of 5.516×10−3min−1·cm−2 were achieved for the thinnest wall. The analysis revealed that the photocatalytic activity of the nanotube arrays was dominated by the dye absorption, environment, light excitation and charge recombination, which would provide structural design for their applications in optoelectronics and photocatalysis.

Studies on the quantitative analysis of an electrochemical solution via the Schlieren method

A quantitative schlieren technique has been applied to measure the change of copper sulfate concentration in an electrochemical cell during the copper electroplating process. We constructed a mathematical model that correlates the grayscale values of schlieren images with the concentration of copper sulfate and analyzed the impact of refraction, reflection, and absorption of light during its passage through the solution on the precision of a schlieren quantitative analysis. Ultimately, by examining the temporal and spatial changes in the distribution of the copper sulfate concentration, we ascertained the impacts of convection, diffusion, and electromigration on the concentration distribution. The impact of the current studies would be greatly expanded in important electrochemical practices such as renewable energy conversions and rechargeable batteries.

A more accurate investigation of XSiN[formula omitted] (X [formula omitted] Ca, Sr, Ba) using a DFT-1/2 scheme

In this work the electronic and optical properties of luminescent materials XSiN2 (X = Ca, Sr, Ba) were revisited based on density function theory (DFT) calculations with a newly developed DFT-1/2 scheme. It was found that the DFT-1/2 correction on nitrogen can well correct the band gaps to approach the experimental values, showing its advantage comparing to the Perdew–Burke–Ernzerhof (PBE) and the Strongly Constrained and Appropriately Normed (SCAN) functionals. Then the electronic band structures and optical properties of the three compounds were investigated using the DFT-1/2 scheme. Within the three compounds, the band gap shows a monotonic decrease along with the atomic number of alkali earth metal mainly due to the downshift of the conduction band edge, where the electronic conductivity is primarily based on electron since it shows a much smaller effective mass than hole. CaSiN2 owns more flat valence bands, while SrSiN2 gives lighter electron. Moreover, the three compounds show high optical absorption, but distinct behavior of light absorption and refractivity in specific energy range, suggesting their applications in optical applications.

The archerfish uses motor adaptation in shooting to correct for changing physical conditions

The archerfish is unique in its ability to hunt by shooting a jet of water from its mouth that hits insects situated above the water’s surface. To aim accurately, the fish needs to overcome physical factors including changes in light refraction at the air-water interface. Nevertheless, archerfish can still hit the target with a high success rate under changing conditions. One possible explanation for this extraordinary ability is that it is learned by trial and error through a motor adaptation process. We tested this possibility by characterizing the ability of the archerfish to adapt to perturbations in the environment to make appropriate adjustments to its shots. We introduced a perturbing airflow above the water tank of the archerfish trained to shoot at a target. For each trial shot, we measured the error, i.e., the distance between the center of the target and the center of the water jet produced by the fish. Immediately after the airflow perturbation, there was an increase in shot error. Then, over the course of several trials, the error was reduced and eventually plateaued. After the removal of the perturbation, there was an aftereffect, where the error was in the opposite direction but washed out after several trials. These results indicate that archerfish can adapt to the airflow perturbation. Testing the fish with two opposite airflow directions indicated that adaptation took place within an egocentric frame of reference. These results thus suggest that the archerfish is capable of motor adaptation, as indicated by data showing that the fish produced motor commands that anticipated the perturbation.

The archerfish uses motor adaptation in shooting to correct for changing physical conditions.

The archerfish is unique in its ability to hunt by shooting a jet of water from its mouth that hits insects situated above the water's surface. To aim accurately, the fish needs to overcome physical factors including changes in light refraction at the air-water interface. Nevertheless, archerfish can still hit the target with a high success rate under changing conditions. One possible explanation for this extraordinary ability is that it is learned by trial and error through a motor adaptation process. We tested this possibility by characterizing the ability of the archerfish to adapt to perturbations in the environment to make appropriate adjustments to its shots. We introduced a perturbing airflow above the water tank of the archerfish trained to shoot at a target. For each trial shot, we measured the error, i.e., the distance between the center of the target and the center of the water jet produced by the fish. Immediately after the airflow perturbation, there was an increase in shot error. Then, over the course of several trials, the error was reduced and eventually plateaued. After the removal of the perturbation, there was an aftereffect, where the error was in the opposite direction but washed out after several trials. These results indicate that archerfish can adapt to the airflow perturbation. Testing the fish with two opposite airflow directions indicated that adaptation took place within an egocentric frame of reference. These results thus suggest that the archerfish is capable of motor adaptation, as indicated by data showing that the fish produced motor commands that anticipated the perturbation.

35‐3: Modeling Eye Movement and Reflection in Virtual Environments for Eye Tracking

Eye movement tracking plays a pivotal role in use interaction within Virtual Reality (VR) environments. Our research focuses on an advanced eye movement simulation using virtual environment for eye tracking training and eye tracking precision evaluating platform. We developed a real‐eye model, enhanced light refraction and corneal reflections under infrared LED light with eye rotation. Our study also customized screen,light source and cameras placement to capture eye images more faithfully. We also presents a noval testing methology and equipments of spatial accuracy testing of the eye‐tracking systems. The proposed proprietary eye‐tracking test system designed to recreate scenarios of human gaze and provide true values for eye gaze directions. Overall, the integration of Pupil Center Corneal Reflection (PCCR) based dataset generation and testing platform mark a significant advancement, enabling huge database, precise groudtruth training and accurate results testing.

Research on underwater robot ranging technology based on semantic segmentation and binocular vision

Based on the principle of light refraction and binocular ranging, the underwater imaging model is obtained. It provides a theoretical basis for underwater camera calibration. In order to meet the requirement of underwater vehicle to identify and distance underwater target, a new underwater vehicle distance measurement system based on semantic segmentation and binocular vision is proposed. The system uses Deeplabv3 + to identify the underwater target captured by the binocular camera and generate the target map, which is then used for binocular ranging. Compared with the binocular ranging using the original drawing, the measurement accuracy of the proposed method has not changed, the measurement speed is increased by 30%, and the error rate is controlled within 5%, which meets the needs of underwater robot operations.