Visible Domain Research Articles

Enhancing Near‐Infrared Absorption in Osmium(II) Complexes Under the Cumulative Influence of Terpyridine Ligand and Anions: Combined Experimental and DFT/TD‐DFT Investigation

AbstractThis work presents synthesis, characterization, and thorough examination on the photophysical and electrochemical behaviours of a new class of homo‐ and heteroleptic Os(II)‐terpyridine complexes. The compounds exhibit intense singlet metal‐to‐ligand charge‐transfer (1MLCT) bands in the visible region (490–500 nm) and weak and broad spin‐forbidden bands in the spectral window of 670–680 nm due to singlet ground state (1GS) to 3MLCT state transition, facilitated by spin‐orbit coupling. The complexes exhibit strong luminescence within 730–750 nm at room temperature having lifetimes in the domain of 101–158 ns, depending upon solvents. Taking advantage of active methylene protons, anion‐induced modulation of spectral and electrochemical characteristics of the complexes has been convincingly demonstrated via different optical channels and spectroscopic tools as well as by cyclic voltammetry. The augmentation in absorption spectral characteristics is quite remarkable in presence of F− and intense absorption bands spanning across the entire visible region and stretching up to NIR domain is achieved. The mode of complex‐anion interplay was elucidated via 1H, 31P{1H} and 19F NMR spectroscopy as well as by computational investigations using DFT and TD‐DFT methods. The complexes also act as molecular sensors and switches that can function in visible and NIR domains upon alternate addition of anion and acid.

Evaluation of SDGSAT-1 MII data in total suspended matter estimation in clear to extremely turbid rivers

ABSTRACT The Multispectral Imager (MII) onboard the newly launched SDGSAT-1 holds significant promise for monitoring and understanding variations in water quality within nearshore water systems, with an impressive spatial resolution of 10 m, seven spectral bands in the visible and near-infrared domain and a wide swath of 300 km. This paper evaluates the MII data in estimating the concentration of total suspended matter (TSM) in rivers and estuaries from clear to extremely turbid conditions. For atmospheric correction, the ACOLITE model showed superior performance compared to the FLAASH and 6SV, with average unbiased relative error (AURE) ranging from 11.8% to 26.4% in the four visible bands of MII. Through comparison, a TSM model based on the visible band ratio (i.e., Rrs (660)/Rrs (560)) was proposed to ensure the application of MII data in both clear and turbid waters, with an overall AURE of 40.9%. The model was then applied to map the TSM variations in the Hai and Liao Rivers in northern China using the MII data, where reliable spatial and temporal patterns were observed. The study concludes by discussing the applicability of MII data in water quality mapping in nearshore waters, along with key considerations such as model applicability, atmospheric correction, and land adjacency.

Enhanced Hg(II) reduction activity over two-dimensional n-n heterojunction MoS2/Bi2WO6 nanocomposites under visible light illumination

Enhanced Hg(II) reduction activity over two-dimensional n-n heterojunction MoS2/Bi2WO6 nanocomposites under visible light illumination

First-principles calculations to investigate Electronic, Optical, Mechanical, and transport characteristics of novel A2BAuCl6 (A = K/Rb/Cs; B = Sc/Y)

First-principles calculations to investigate Electronic, Optical, Mechanical, and transport characteristics of novel A2BAuCl6 (A = K/Rb/Cs; B = Sc/Y)

Reflectance spectrometry and multispectral data for mapping fractures and hydrothermal alterations in the northern edge of the eastern High Atlas, Morocco

Reflectance spectrometry and multispectral data for mapping fractures and hydrothermal alterations in the northern edge of the eastern High Atlas, Morocco

Investigating the effect of Pb doping on the structural, electronic, magnetic, and optical properties of wurtzite CdS

Investigating the effect of Pb doping on the structural, electronic, magnetic, and optical properties of wurtzite CdS

Inf-OSRGAN: Optimized Blind Super-Resolution GAN for Infrared Images

With the widespread application of infrared technology in military, security, medical, and other fields, the demand for high-definition infrared images has been increasing. However, the complexity of the noise introduced during the imaging process and high acquisition costs limit the scope of research on super-resolution algorithms for infrared images, particularly when compared to the visible light domain. Furthermore, the lack of high-quality infrared image datasets poses challenges in algorithm design and evaluation. To address these challenges, this paper proposes an optimized super-resolution algorithm for infrared images. Firstly, we construct an infrared image super-resolution dataset, which serves as a robust foundation for algorithm design and rigorous evaluation. Secondly, in the degradation process, we introduce a gate mechanism and random shuffle to enrich the degradation space and more comprehensively simulate the real-world degradation of infrared images. We train an RRDBNet super-resolution generator integrating the aforementioned degradation model. Additionally, we incorporate spatially correlative loss to leverage spatial–structural information, thereby enhancing detail preservation and reconstruction in the super-resolution algorithm. Through experiments and evaluations, our method achieved considerable performance improvements in the infrared image super-resolution task. Compared to traditional methods, our method was able to better restore the details and clarity of infrared images.

REAL ESTATE, PHOTOGRAPHY, AND CAPITALIST ABSTRACTION. ON EDGAR MARTINS’ THIS IS NOT A HOUSE, DANIEL SHEA’S 43-35 10TH STREET, AND LEWIS BUSH’S METROPOLE

The paper analyses three photographic bodies of work — Edgar Martins’ This Is Not a House, Daniel Shea’s 43-35 10th Street, and Lewis Bush’s Metropole — looking at various aspects of the real estate market: real estate collapse and the 2008 financial crisis in the USA, as well as real estate boom and gentrification in New York City and London. The case studies depict the real estate industry as an example of how invisible and abstract market processes shape visible and concrete domains of everyday life, such as, income inequalities, social relationships, or public space aesthetics. The artists in question use photography as a tool to deconstruct the abstractions of neoliberal capitalism through an attempt to visualise the invisible. By examining the three case studies in the light of economic theory on the real estate market, the paper defines links between neoliberal capitalism and the medium of photography using the idea of abstraction, and shows how photography is used to dissect the complexity of economic processes taking place within the realm of neoliberal capitalism.

In-situ observations of resident space objects with the CHEOPS space telescope

In-situ observations of resident space objects with the CHEOPS space telescope

Electrical Conduction Mechanism of Mg-Doped ZrO2 Thin Films.

Amorphous ZrO2 thin films with increasing Mg content were deposited on quartz substrates, by dip coating method. The films are transparent in the visible domain and absorbent in UV, with an optical band gap that decreases with the increase of Mg content, from 5.42 eV to 4.12 eV. The temperature dependent conductivity measurements showed typical semiconductor comportment. The decrease of the electrical conductivity by Mg doping was related to the increase of the OH groups (37% to 63%) as seen from X-ray Photoelectron Spectroscopy. It was found out that the electrical conductivity obeys the Meyer-Neldel rule. This rule, previously reported for different disordered material systems is obtained for ZrO2 for the first time in the literature. Exploring novel aspects of Mg-doped ZrO2, the present study underscores the origin of the Meyer-Neldel rule explained by the small-polaron hopping model in the non-adiabatic hopping regime. Determination of the presence of such a conduction mechanism in the samples hold promise for comprehending the important aspects, which might be a concern in developing various devices based on Mg-doped ZrO2.

The Aesthetics of the Invisible—At the Margins of Phenomenology

ABSTRACT The paper focuses on the complex relations between aesthetics and phenomenology as they show themselves within the core locus of their interplay—the realm of the visible and the invisible. To do so, the paper examines a specific case study, a Rembrandt painting—A Woman Bathing in a Stream (1654)—through which the discussion illuminates the interconnected and inseparable relationship between aesthetics and phenomenology in relation to Merleau-Ponty’s ontology of the visible and the invisible. The reading addresses both dimensions of the visible: the essential intersubjective aspect of life and its complex visual representation in art. To achieve this, the paper first explores Merleau-Ponty’s late aesthetic ontology—a phenomenology that perceives the aesthetic realm, particularly the visible domain, as originating from human corporeal existence, thereby redefining the act of seeing and the concepts of the visible and the invisible; I show the manner in which invisible elements permeate our visual experience in the Rembrandt painting and in seeing as such. The paper also reveals the unique ontological role of painting and the painter in unveiling the aesthetic world, and in guiding the philosopher toward a vision that true philosophy—phenomenology—must embrace. The paper concludes by rethinking the significance of aesthetics, and especially, the arts, to phenomenological thought, and the necessity of phenomenology to aesthetic thought.

High stability and photocatalytic activity of N-doped ZrO2 thin films

High stability and photocatalytic activity of N-doped ZrO2 thin films

Antimicrobial Packaging for Plum Tomatoes Based on ZnO Modified Low-Density Polyethylene.

Food safety and quality are major concerns in the food industry. Despite numerous studies, polyethylene remains one of the most used materials for packaging due to industry reluctance to invest in new technologies and equipment. Therefore, modifications to the current materials are easier to implement than adopting whole new solutions. Antibacterial activity can be induced in low-density polyethylene films only by adding antimicrobial agents. ZnO nanoparticles are well known for their strong antimicrobial activity, coupled with low toxicity and UV shielding capability. These characteristics recommend ZnO for the food industry. By incorporating such safe and dependable antimicrobial agents in the polyethylene matrix, we have obtained composite films able to inhibit microorganisms' growth that can be used as packaging materials. Here we report the obtaining of highly homogenous composite films with up to 5% ZnO by a melt mixing process at 150 °C for 10 min. The composite films present good transparency in the visible domain, permitting consumers to visualize the food, but have good UV barrier properties. The composite films exhibit good antimicrobial and antibiofilm activity from the lowest ZnO composition (1%), against both Gram-positive and Gram-negative bacterial strains. The homogenous dispersion of ZnO nanoparticles into the polyethylene matrix was assessed by Fourier transform infrared microscopy and scanning electron microscopy. The optimal mechanical barrier properties were obtained for composition with 3% ZnO. The thermal analysis indicates that the addition of ZnO nanoparticles has increased thermal stability by more than 100 °C. The UV-Vis spectra indicate a low transmittance in the UV domain, lower than 5%, making the films suitable for blocking photo-oxidation processes. The obtained films proved to be efficient packaging films, successfully preserving plum (Rome) tomatoes for up to 14 days.

Improved near-resonant two photon absorption of α-MnO2 nanowires surface functionalized reduced graphene oxide sheets

Improved near-resonant two photon absorption of α-MnO2 nanowires surface functionalized reduced graphene oxide sheets

Greening in the spotlight: How public inquisitiveness shapes European SMEs' actions in response to climate concerns

AbstractWe examine greening activities among European small and medium‐sized enterprises (SMEs) in the product and process domains, and argue that greater public climate concern in an SME's home country environment primarily associates with greening in the inherently more visible product domain. Moreover, we introduce the concept of public inquisitiveness and propose that greater inquisitiveness prompts SMEs to also pay attention to less visible process greening activities as a response to public climate pressures. We test our ideas using multilevel regression models on a large representative sample of SMEs from 18 European Union (EU) countries. The study's main ideas are supported by the findings, which point to possible trade‐offs between product and process greening among resource‐constrained SMEs, and suggest the general public's inquisitiveness indeed plays a key role in preventing under engagement in less outwardly visible greening strategies. We discuss our study's implications for discourse on how and under which conditions normative institutional forces shape firm‐level sustainable behavior, as well as for SMEs' pro‐environmental stakeholders.

Application of Optical Emission Spectroscopy to Electron Cyclotron Resonance Ion Sources

Electron Cyclotron Resonance Ion Sources (ECRIS) are widely used for production of highly charged high intensity ion beams for research, medical and industrial applications.ECRIS performances, especially the charge state distribution and beam intensity, depend significantly on the electron energy distribution function that ranges from a few eV to hundreds of keV. Further improvements of ECRIS performances require a deeper and deeper understanding of the plasma heating mechanisms and ion generation by means of opportune plasma diagnostics. Amongst others, optical emission spectroscopy (OES) is the most remarkable for application in ECRIS: it is a non-invasive diagnostics able to operate also in high-voltage conditions and it requires small room for operation. OES has been already tested for plasma diagnostics in proton sources.This work presents the experimental set-up developed for the plasma diagnostics of the Advanced Ion Source for Hadrontherapy (AISHa), an ECRIS for medical applications, together with the strategy applied to relate plasma emission lines in the visible and near-infrared domain to plasma parameters for some ions of interest. Preliminary results and perspectives will be also discussed.

Calculation and experiment of carpet illusionary cloaking modeling based on coding metasurface

Calculation and experiment of carpet illusionary cloaking modeling based on coding metasurface

Thermo‐Optical Switches Based on Spin‐Crossover Molecules with Wideband Transparency

AbstractIn this work, a thermally tunable optical resonator operating in the visible wavelength range is reported, which consists of a bilayer structure composed of a thin silver layer and a dielectric coating of [Fe(HB(1,2,4‐triazol‐1‐yl)3)2] switchable spin‐crossover (SCO) molecules. White light is coupled to the resonant structure using a prism and the resulting resonance spectra are investigated as a function of the incident angle and temperature. Switching the SCO molecules from the low‐spin to the high‐spin state gives rise to a substantial blueshift of the resonances reaching up to 30 nm (associated with a reflectance modulation of up to 70%), which can be linked, through transfer‐matrix simulations, to the variation of the optical thickness of the molecular layer. Interestingly, the study demonstrated that the large thermal tunability of the device also gives rise to a photothermal nonlinearity, which can be leveraged for achieving optical limiting applications. Overall, through the present study, it is shown that molecular SCO nanomaterials can be superior to commonly used thermo‐optical switches and well‐established optical phase‐change materials for applications requiring high broadband optical transparency in the visible spectral domain.

Three-dimensional Atmospheric Dynamics of Jupiter from Ground-based Doppler Imaging Spectroscopy in the Visible

We present three-dimensional (3D) maps of Jupiter’s atmospheric circulation at cloud-top level from Doppler-imaging data obtained in the visible domain with JIVE, the second node of the JOVIAL network, which is mounted on the Dunn Solar Telescope at Sunspot, New Mexico. We report on 12 nights of observations between 2018 May 4 and May 30, representing a total of about 80 hr. First, the average zonal wind profile derived from our data is compatible with that derived from cloud-tracking measurements performed on Hubble Space Telescope images obtained in 2018 April from the Outer Planet Atmospheres Legacy program. Second, we present the first ever 2D maps of Jupiter’s atmospheric circulation from Doppler measurements. The zonal velocity map highlights well-known atmospheric features, such as the equatorial hot spots and the Great Red Spot (GRS). In addition to zonal winds, we derive meridional and vertical velocity fields from the Doppler data. The motions attributed to vertical flows are mainly located at the boundary between the equatorial belts and tropical zones, which could indicate active motion in theses regions. Qualitatively, these results compare well to recent Juno data that have unveiled the 3D structure of Jupiter’s wind field. To the contrary, the motions attributed to meridional circulation are very different from what is obtained by cloud tracking, except at the GRS. Because of limitations with data resolution and processing techniques, we acknowledge that our measurements of the vertical or meridional flows of Jupiter are still to be confirmed.

Growth and spectroscopic properties of Ca3(Ta,Ga)5O12:Pr3+ single crystal as a promising new laser material in the visible domain

Growth and spectroscopic properties of Ca3(Ta,Ga)5O12:Pr3+ single crystal as a promising new laser material in the visible domain