Dispersive Component Research Articles

Roles of London Dispersive and Polar Components of Nano-Metal-Coated Activated Carbons for Improving Carbon Dioxide Uptake

Adsorption using carbonaceous materials has been considered as the prevailing technology for CO2 capture because it offers advantages such as high adsorption capacity, durability, and economic benefits. Activated carbon (AC) has been widely used as an adsorbent for CO2 capture. We investigated CO2 adsorption behaviors of magnesium oxide-coated AC (MgO-AC) as a function of MgO content. The microstructure and textural properties of MgO-AC were characterized by X-ray diffraction and nitrogen adsorption–desorption isotherms at 77 K, respectively. The CO2 adsorption behaviors of MgO-AC were evaluated at 298 K and 1 atm. Our experimental results revealed that the presence of MgO plays a key role in increasing the CO2 uptake through the interaction between an acidic adsorbate (e+) and an efficient basic adsorbent (e−).

New Methodology to Study the Dispersive Component of the Surface Energy and Acid-Base Properties of Silica Particles by Inverse Gas Chromatography at Infinite Dilution.

A new methodology was proposed to determine the dispersive component of the surface energy ${\gamma}_s^d$ of a solid taking into account the effect of the temperature on the surface area of n-alkanes, methylene group (${a}_{- CH2-}$) and polar molecules, thus defeating the method used by Dorris-Gray Schultz etal. We determined the correct ${\gamma}_s^d$ of the surface energy, the specific free energy, enthalpy and entropy of adsorption of polar molecules as well as the acid base constants of silica particles with an excellent accuracy. We confirmed the dependence of the dispersive component of the surface energy on the variations of the surface areas of organic molecules used in IGC technique at infinite dilution. The specific properties of interactions of silica particles were determined. The new proposed model took into account this thermal effect. Obtained results proved that the other used IGC methods gave inaccurate values of the specific parameters of silica surface, except for the vapor pressure method that led to excellent results of the specific free energy, enthalpy and entropy of adsorption, and the acid-base constants of the silica particles.

Change in the surface roughness and surface free energy of Samama (Anthocephalus macrophyllus) after citric acid impregnation through pre-compression method

This research aims at detecting the hydrophobicity change in Samama (Anthocephalus macrophyllus) wood surface after hydro-thermo-mechanical modification. The modification started by soaking the test piece until water-saturated, followed with pre-compression at 100 °C for an hour. The second stage was impregnation of citric acid 10% using autoclave at pressure 7.5 kg cm−2 for 4 h. The other test piece was only impregnated using distilled water, without citric acid, with the same pressure within the same time. Further, the second compression was conducted on the test piece impregnated only with distilled water and citric acid. It was conducted at 180 °C for 10, 20, 30, 40, 50 and 60 min. The compaction target was 20%. After conditioning for 2 weeks at room temperature (25 °C) and RH 85%, the test piece was soaked in distilled water for 24 h for the spring back test. The surface roughness and surface free energy were tested after the spring back test. The test result shows that the tangential surface of Samama wood impregnated with citric acid and compressed for 50 min (type CA50) has the smoothest tangential surface. The type also has the lowest SFE value of 36.193 mJ m−2. In addition, the dispersive component of densified Samama wood surface seems to increase and, on the contrary, its polar component is reduced. The wood radial surface impregnated with citric acid tends to be rougher with a higher total SFE value than that of the tangential surface.

The Earnings Expectations Game and the Dispersion Anomaly

This study examines the role of differences in firms’ propensity to meet earnings expectations in explaining why firms with high analyst forecast dispersion experience relatively low future stock returns. We first demonstrate that the negative relation between dispersion and returns is concentrated around earnings announcements. Next, we show that this relation disappears when we control for ex ante measures of firms’ propensity to meet earnings expectations and that the component of dispersion explained by these measures drives the return predictability of dispersion. We further demonstrate that firms with low analyst dispersion are substantially more likely to achieve positive earnings surprises and provide new evidence consistent with both expectations management and strategic forecast pessimism explaining this result. Overall, we conclude that investor mispricing of firms’ participation in the earnings-expectations game provides a viable explanation for the dispersion anomaly. This paper was accepted by Brian Bushee, accounting.

New solid forms of the diuretic compound 4-Chloro Salicylic Acid-5-Sulfonamide

Four multi-component solid forms of the diuretic compound 4-Chloro Salicylic Acid-5-Sulfonamide (CSAS), including two hydrates (named as 2-hydrate, 3-hydrate), one cocrystal with benzoic acid (named as 4-cocrystal) and a cocrystal-solvate of 4,4’ bipyridine (BIP) with 1,4 dioxane (denoted as 5-multicomp) were successfully obtained. The crystal structures were determined by X-ray single crystal technique and further, the structural characterization was made by XRPD and FT-IR. The total lattice energy, which can be partitioned in Coulombic, polarization, dispersion and repulsion components has been computed using the atom-atom Coulomb-London-Pauli forcefield approximation (AA-CLP). For the two hydrates, the diuretic molecules and water molecules are connected to each other via N-H…O and O-H…O hydrogen bonds. The cocrystal with benzoic acid has the diuretic molecule linked to benzoic acid in a 1:1 stoechiometric manner via carboxyl-carboxyl O-H…O hydrogen bonds, forming a R22(8) homosynthon. The multicomponent cocrystal-solvate system is stabilized by a combination of C-H…O and N-H…O hydrogen bonds between the solvent, 4,4’ bipyridine and the starting compound.

Changes in Surface Free Energy and Surface Conductivity of Carbon Nanotube/Polyimide Nanocomposite Films Induced by UV Irradiation.

Changes in surface energy and electrical conductivity of polyimide (PI)-based nanocomposite films filled with carbon nanotubes (CNTs) induced by UV exposure are gaining considerable interest in microelectronic, aeronautical, and aerospace applications. However, the underlying mechanism of PI photochemistry and oxidation reactions induced by UV irradiation upon the surface in the presence of CNTs is still not clear. Here, we probed the interplay between CNTs and PIs under UV exposure in the surface properties of CNT/PI nanocomposite films. Changes in contact angles and surface electrical conductivity at the surface of CNT/PI nanocomposite films after UV exposure were measured. The unpaired electron intensity of free radicals generated by UV exposure was monitored by electron paramagnetic resonance. Our study indicates that the covalent interactions between CNTs and radicals generated by UV irradiation on the PI surfaces tailor the surface energy and surface conductivity through anchoring radicals on CNTs. Surprisingly, adding CNTs into PI films exposed to UV leads to antagonistic contributions of dispersion and polar components to the surface energy. The surface electrical conductivity of the CNT/PI nanocomposite films has been improved due to an enhanced hopping behavior with dense π-conjugated CNT sites. To explain the observed changes in surface energy and surface conductivity of CNT/PI nanocomposite films induced by UV exposure, a qualitative model was put forward describing the covalent interactions between UV-induced PI free radicals and CNTs, which govern the chemical nature of surface components. This study is helpful for characterizing and optimizing nanocomposite surface properties by tuning the covalent interactions between components at the nanoscale.

CLIFF: A component-based, machine-learned, intermolecular force field

Computation of intermolecular interactions is a challenge in drug discovery because accurate ab initio techniques are too computationally expensive to be routinely applied to drug-protein models. Classical force fields are more computationally feasible, and force fields designed to match symmetry adapted perturbation theory (SAPT) interaction energies can remain accurate in this context. Unfortunately, the application of such force fields is complicated by the laborious parameterization required for computations on new molecules. Here, we introduce the component-based machine-learned intermolecular force field (CLIFF), which combines accurate, physics-based equations for intermolecular interaction energies with machine-learning models to enable automatic parameterization. The CLIFF uses functional forms corresponding to electrostatic, exchange-repulsion, induction/polarization, and London dispersion components in SAPT. Molecule-independent parameters are fit with respect to SAPT2+(3)δMP2/aug-cc-pVTZ, and molecule-dependent atomic parameters (atomic widths, atomic multipoles, and Hirshfeld ratios) are obtained from machine learning models developed for C, N, O, H, S, F, Cl, and Br. The CLIFF achieves mean absolute errors (MAEs) no worse than 0.70kcal mol-1 in both total and component energies across a diverse dimer test set. For the side chain-side chain interaction database derived from protein fragments, the CLIFF produces total interaction energies with an MAE of 0.27kcal mol-1 with respect to reference data, outperforming similar and even more expensive methods. In applications to a set of model drug-protein interactions, the CLIFF is able to accurately rank-order ligand binding strengths and achieves less than 10% error with respect to SAPT reference values for most complexes.

Application of non-ionic surfactant in modifying the surface of carbon black and its role in the formation of colloidal composite materials

In this work, carbon black (CB)/silica colloidal composites were synthesized using a surface adsorption methodology. A unique biocompatible, amphiphilic, non-ionic polysorbetol monoelate easter (Tween 80) surfactant was used to enhance surface activity and wettability of CB aggregates. A metal alkoxide (tetraethoxysilane) was used as precursor for silica precipitation in an acid catalyzed reaction. The precipitated silica gets adsorbed onto surfactant modified CB aggregate via an interactive hydrophilic layer. This results in formation of different configurations of CB/silica colloidal composite, which was characterized by morphological studies. The chemical extraction study was done to quantify, the amount of silica present in CB/silica colloidal composites and observation were further supported by energy dispersive x-ray (EDX) analysis. The x-ray diffraction (XRD) characterizes, the structural arrangement of synthesized materials. The surface-free energies studies by inverse gas chromatography (IGC) were done to understand changes in dispersive and polar component of CB-silica composite compared to conventional filler materials. The distribution of silica in CB/silica composite aggregates was uniform up to adsorption level of 5 wt%. Further, increase in the level of silica adsorption leads to flocculation, causing agglomerated composites. The results obtained encourage adaptation of a simple, low-cost and environmentally friendly process to promote synthesis of CB/silica composite material.

The interplay between mutualism, competition and dispersal promotes species coexistence in a multiple interactions type system

The stability and maintenance of species biodiversity in the multiple interactions type systems have attracted much attention. Regardless of their nature, several forms of interactions are discovered to exhibit oscillatory behaviour. This large-amplitude oscillation also de-stabilizes populations of multiple species and raises species’ chances of extinction. A central question in ecology is how do we maintain community stability and species coexistence mechanisms in a multiple interactions type community. It is thought that the dynamics of mutualism support multi-species coexistence in a complex ecological system. Here, we extend a four-species multiple interactions type (e.g., resource-competitor-exploiter-mutualist) system by incorporating a local dispersal component. We then employ this model to assess how the combined impacts of dispersal, mutualism and competition shape species coexistence and community stability in this ecological system. Our findings show that the interplay of mutualism and competition affects the complexity of ecological dynamics in this multiple interactions type system with local dispersal. Using numerical simulation, we demonstrate how strong mutualism could stabilize the spatio-temporal dynamics. Employing bifurcation analysis, we also discover that mutualism essentially modifies this ecological community’s response to increasing competitive pressure on the resource species. These insights are evident in our findings through the emergence of intriguing dynamics where stable limit cycles alternate with unstable ones as competitive pressure varies. While alternative stable states are common in different ecological systems with mutualistic interactions, they are often stable, whereas, in our studies, we realize that there can be alternative stable or unstable states if the spatial dimension is considered through the incorporation of the diffusion component. Consequently, the long-term dynamics converge to multi-species coexistence outcomes either via a stable steady state or a limit cycle depending on species’ initial abundances. It is also observed that this complexity ceases when mutualism becomes strong enough. Additionally, the destabilization of species biodiversity phenomenon through the occurrence of limit cycles increasing in the amplitude of oscillations (with some species population densities approaching zero) is weakened in the presence of strong mutualistic strength and local dispersal. Overall, the joint effects of mutualism, competition and local dispersal result in different community compositions, and these insights may have significant consequences in conservation management and biological control strategies.

Building Systems Based on Foamed Modified Polymers

Systems of floor insulation on the ground, isolation of roads and shallow foundations suggest the use of heat-insulating products resistant to moisture, the minerals contained in it, having low heat conductivity and water absorption and relatively high strength for compressive loads.The aim of the research was to study the possibility of using mineral substances containing crystalline water as a dispersed component. Firstly, such compounds as a reinforcing component increase the strength characteristics of products. Secondly, being flame retardants, they contribute to increasing the fire safety of materials and building systems in which these materials are used. To achieve this goal, two particular tasks were set: determination of the optimal consumption of mineral modifying additives; assessment of exploitative stability of the received products. It was found that the introduction of a mineral modifying additive can significantly increase the compressive strength by 10% deformation of samples from extruded polystyrene foam. The exploitative stability of products with a mineral additive varies slightly and depends on its consumption and uniform distribution in the product matrix. The effect of additive consumption on the change in the thermal conductivity of products has not been established. A nomogram has been built which allows one to evaluate the properties of products and determine the optimal consumption of a modifying additive.Systems of using products from modified extruded polystyrene foam in monolithic foundations with insulation for buildings erected on problem soils are considered.

New Methods for the Determination of the Surface Physicochemical Properties and Glass Transition of Polyaniline in Conducting and Non-Conducting Forms by Using Igc Technique at Infinite Dilution

Many studies were devoted in our Laboratory to the determination of physico-chemical and thermodynamic properties of polymers and/or oxides by using the inverse gas chromatography (IGC) at infinite dilution. More particularly, we studied the interactions of solid substrates with some model organic molecules and their acid-base properties, in Lewis terms, by determining the acidic and basic constants. We proposed in this paper to study the surface thermodynamic energetics, transition phenomena, specific interactions and acid-base properties of both the conducting polyaniline (PANI-HEBSA) and the non-conducting form (PANI-EB) on the light of the new progresses of IGC methods. This technique was used to obtain the net retention volume Vn and then the dispersive free enthalpy of n-alkanes adsorbed on PANI. The curves of the dispersive component of the surface energy of n-alkanes adsorbed on PANI, as a function of the temperature highlighted the presence of two transition temperatures on 383K and 430K respectively for PANI-HEBSA and PANI-EB. There results were confirmed by the curves of RTlnVn =f(1/T) of n-alkanes. The determination of the specific free enthalpy of polar molecules adsorbed on PANI proved a shift of 4K in the value of the glass transition of PANI-EB. From the variation of as a function of the temperature, one deduced the values of the specific enthalpy of the various polar molecules and determined the acidic constant KA and basic constant KD, the two constants characterizing the solid substrate. It was showed that PANI is highly more basic than acidic (about 2.6 times more basic) and an increase of the acid-base character was highlighted near the glass transition for PANI-EB.

Synthesis of low surface energy thin films of nonhalogenated polyepichlorohydrin-triazoles with side alkyl chain

The dispersive and polar components of surface energy of a polymer thin film are hypothesized to be reduced by introduction of intramolecular interactions to pull side chains to the backbone and by establishment of hydrophobic interactions between extended alkyl chains to compact the molecular volume. A series of new polymer, polyepichlorohydrin (PECH)-triazole polymer with side chain with different number of methylene groups, were synthesized to prove this proposal. The newly synthesized polymer has high film-formation capacity and no halogens. The interactions between ether oxygen and imine nitrogen atoms depress the dipole effects and the hydrophobic interactions between extended methylene groups of the side chain on triazole compact the molecular volume, so the yielded surface energy has been effectively reduced to a level lower than PTFE. The synthesized polymer is a nonhalogenated low surface-energy material with potential applications.

Bifurcation of chemically driven self-propelled droplets on a surfactant-adsorbed surface based on spreading coefficients

The bifurcation of the self-propelled motion of a reactive fluid on a solid surface is of fundamental interest in the haptotaxis of cells, cellular adhesion, and the energy conversion of active matter. Changes in the wettability of a solid surface due to chemical reactions are significantly related to bifurcation, with the thermodynamic factors primarily accounting for the substrate–droplet interaction energy, and the kinetic factors determining the time constant of the formation of the wettability gradient. However, no quantitative experiments have been performed to elucidate bifurcation with consideration of the time-dependent change in the wettability under nonequilibrium conditions with the purpose of determining the contributions of the thermodynamic and kinetic factors to droplet motion. In this study, we systematically varied the wettability of a surfactant-adsorbed solid surface by adjusting the pH of the surrounding fluid and quantitatively investigated the relationship between bifurcation, which arrests self-propelled droplet motion, and the spreading coefficient that determine the disjoining pressure. The size-dependent droplet velocity is consistent with the indications of a model that considers the kinetic factors of the relevant chemical reactions. In addition, bifurcation occurred when the sign of the thermodynamically determined dispersive component of the spreading coefficient changed, corresponding to a change in the direction of the disjoining pressure. Our analysis of the time-dependent spreading coefficient has the potential for contributing to the elucidation of various bifurcation phenomena induced by a change in the wettability gradient through consideration of both the thermodynamic and kinetic factors of the relevant chemical and physical reactions.

Evidence for intermolecular forces involved in ladybird beetle tarsal setae adhesion

Why can beetles such as the ladybird beetle Coccinella septempunctata walk vertically or upside-down on a smooth glass plane? Intermolecular and/or capillary forces mediated by a secretion fluid on the hairy footpads have commonly been considered the predominant adhesion mechanism. However, the main contribution of physical phenomena to the resulting overall adhesive force has yet to be experimentally proved, because it is difficult to quantitatively analyse the pad secretion which directly affects the adhesion mechanism. We observed beetle secretion fluid by using inverted optical microscopy and cryo-scanning electron microscopy, which showed the fluid secretion layer and revealed that the contact fluid layer between the footpad and substrate was less than 10–20 nm thick, thus indicating the possibility of contribution of intermolecular forces. If intermolecular force is the main physical phenomenon of adhesion, the force will be proportional to the work of adhesion, which can be described by the sum of the square roots of dispersive and polar parts of surface free energy. We measured adhesion forces of ladybird beetle footpads to flat, smooth substrates with known surface free energies. The adhesive force was proportional to the square-root of the dispersive component of the substrate surface free energy and was not affected by the polar component. Therefore, intermolecular forces are the main adhesive component of the overall adhesion force of the ladybird beetle. The footpads adhere more strongly to surfaces with higher dispersive components, such as wax-covered plant leaves found in the natural habitat of ladybird beetles. Based on the present findings, we assume ladybird beetles have developed this improved performance as an adaptation to the variety of plant species in its habitat.

New insights into star cluster evolution towards energy equipartition

ABSTRACT We present the results of a study aimed at exploring the evolution towards energy equipartition in star cluster models with different initial degrees of anisotropy in the velocity distribution. Our study reveals a number of novel aspects of the cluster dynamics and shows that the rate of evolution towards energy equipartition (i) depends on the initial degree of radial velocity anisotropy – it is more rapid for more radially anisotropic systems; and (ii) differs for the radial and the tangential components of the velocity dispersion. (iii) The outermost regions of the initially isotropic system evolve towards a state of ‘inverted’ energy equipartition in which high-mass stars have a larger velocity dispersion than low-mass stars – this inversion originates from the mass dependence of the tangential velocity dispersion whereas the radial velocity dispersion shows no anomaly. Our results add new fundamental elements to the theoretical framework needed to interpret the wealth of recent and upcoming observational studies of stellar kinematics in globular clusters, and shed further light on the link between the clusters’ internal kinematics, their formation, and evolutionary history.

Encapsulation of bimetallic phosphides into graphitized carbon for pH-universal hydrogen evolution reaction

Exploring nonprecious electrocatalysts for water splitting with high efficiency and durability is critically important. Herein, bimetallic phosphides are encapsulated into graphitized carbon to construct a C@NiCoP composite nanoarray using bimetallic metal–organic framework (MOF) as a self-sacrificial template. The resulting C@NiCoP exhibits superior performance for pH-universal electrocatalytic hydrogen evolution reaction (HER), particularly representing a low overpotential of 46.3 mV at 10 mA cm−2 and Tafel slope of 44.1 mV dec−1 in alkaline media. The structural characterizations combined with theoretical calculation demonstrate that tailored electronic structure from bimetal atoms and the synergistic effect with graphitized carbon layer could jointly optimize the adsorption ability of hydrogen on active sites in HER process, and enhance the electrical conductivity as well. In addition, the carbon layer served as a protecting shell also prevents highly dispersed NiCoP components from agglomeration and/or loss in harsh media, finally improving the durability. This work thus provides a new insight into optimizing activity and stability of pH-universal electrocatalysts by the nanostructural design and electronic structure modulation.

Engineering Molecular Polymerization for Template‐Free SiOx/C Hollow Spheres as Ultrastable Anodes in Lithium‐Ion Batteries

AbstractSiOx/C composites with a void‐reserving structure are promising anodes for lithium‐ion batteries. However, the facile and controllable synthesis of uniformly dispersed SiOx and carbon components, simultaneously incorporating ample voids, still remains a great challenge. Herein, a molecular polymerization strategy is devised to construct SiOx/C hollow particles for lithium‐ion batteries. 3‐aminopropyltriethoxysilane and dialdehyde molecules are judiciously engineered as silicon and carbon precursors to produce the polymer hollow spheres (PHSs) through a one‐step aldimine condensation without any template and additive. A range of PHSs is obtained using terephthalaldehyde, glutaraldehyde, and glyoxal as the crosslinkers, demonstrating the high tunability of the strategy. Importantly, in situ pyrolysis of the PHSs warrants the homogeneous incorporation of SiOx (<5 nm) in carbon hollow capsids at a nanocluster scale. The obtained SiOx/C hollow spheres exhibit excellent Li+‐ion storage behaviors, including cycling lifespan, coulombic efficiency, and rate performance. The superior performance is attributed to the well‐dispersed SiOx nanoclusters in carbon substrate and the hollow structure. This molecular polymerization approach not only enables Si‐based hollow composites effective and scalable anode materials but also opens up a new avenue for the controllable synthesis of template‐free hollow architectures.

Ammonia storage/release behaviors of the CeSn0.2Mo0.6Ox/TiO2 catalyst in selective catalytic reduction of NO

• CeSnMoO x /TiO 2 obtained stable NO removal due to ammonia storage/release. • Excess NO induced ammonia release, the amount reached maximum during 250−300 °C. • Ammonia was mainly stored in physical form and partly by chemical adsorption. • High temperature enhanced ammonia activation and improved ammonia release. This work explored the ammonia storage/release behaviors of the CeSn 0.2 Mo 0.6 O x /TiO 2 catalyst in selective catalytic reduction of NO. Results displayed that the CeSn 0.2 Mo 0.6 O x /TiO 2 performed much higher NO removal rate than the theoretical maximum if the NH 3 /NO ratio was lower than one, which was due to the ammonia storage/release behaviors. The ammonia storing was more likely to occur at low temperatures, and the storage capacity of the catalyst reached 27 μmol m −2 at 50 °C. Moreover, ammonia exists mainly on physical form of temperatures below 250 °C and is adsorbed in weakly acidic sites; while high temperature strengthen activation of strong acid sites, resulting in increasing the ammonia storage at 350 °C. NH 3 -TPD results showed two peaks of ammonia desorption, indicating the weak and strong acid sites of the catalyst. The ammonia storage/release curves at Constant Temperature Flow Field were asymmetric and BET isotherm showed Type H3 hysteresis loop, which was caused by mass transfer in the plate-like pore structure formed by the particle polymerization. The porous structure and highly dispersed active components were beneficial for storing ammonia. The effective utilization ratio of the stored ammonia decreased with the increasing temperature and GHSV.

Silanization of siliceous materials, part 3: Modification of surface energy and acid-base properties of silica nanoparticles determined by inverse gas chromatography (IGC)

Surface modified silica nanoparticles are well-established composite materials. To improve their embedding and application behavior, surface energy analysis has been performed before and after silanization with mercaptopropyltrimethoxysilane (MPTMS) using inverse gas chromatography technique (IGC). Experiments with two silica materials have been conducted at infinite dilution to determine the dispersive component of the surface energy (γsd) as well as the specific component (γssp) using the van Oss theory and a least-squares procedure evaluating the IGC data of 8 polar probe molecules collectively (instead of evaluating only the data of a pair of monopolar probes as is often the case in IGC studies). After surface silylation, the total surface energy (γst) of pyrogenic silica nanoparticles decreased from 225 mJ/m2 to 149 mJ/m2 referring to both a reduced wettability and an increased hydrophobicity of the MPTMS-modified sample. Moreover, the acidity/basicity parameters according to the van Oss and the Gutmann approach indicated that the acidity of the silica surface decreases by MPTMS grafting. In addition, IGC at finite concentration (using isopropanol as probe molecule) was applied to obtain the energetic heterogeneity of the silica surface. The results showed a bimodal energy distribution with maxima at about 18 and 25 kJ/mol and a reduction of the higher energetic sites from 65% to only 35% after MPTMS treatment. Overall, it can be seen that the dominance of specific interactions on silica surfaces is maintained even after extensive silanization. These findings are in agreement with the results of 29Si CP MAS NMR measurements which confirm the assignment of higher energetic sites to silanol groups. For the interpretation of the IGC results, quantum chemical calculations proved the preferred interaction of isopropanol onto silica surfaces via hydrogen bridging.

Compressive circular polarization snapshot spectral imaging

A compressive sensing based circular polarization snapshot spectral imaging system is proposed in this paper to acquire two-dimensional spatial, one-dimensional circular polarization (the right and left circular polarization), and one-dimensional spectral information by one snapshot measurement, simultaneously. The dispersed component combined with a double Amici prism and a Wollaston prism was used to implement the spectral shifting along two orthogonal directions. Theoretically, the spectral resolution could be improved compared with the traditional coded aperture snapshot spectral imager proposed by Brady et al. The right and left circular polarization components are extracted by the assembly with an achromatic quarter wave-plate and a Wollaston prism. The encoding and reconstruction are illustrated comprehensively. The feasibility and fidelity are verified from the aspects of image and spectral reconstruction evaluations. It provides us an alternative approach for circular polarization spectral imaging for the dynamic objects in the fields such as defogging, underwater imaging, insects detection, and so on.