Search

ObjectivesThe absorption and regeneration properties of different formulations of methyldiethanolamine (MDEA) mixed with different diamines were studied.MethodsIn the simulated flue gas environment with 12% CO2 and 88% N2, MDEA was used as the main agent, while ethylenediamine (EDA), 1,3-diaminopropane (DAP), N-methyl-1,3-propanediamine (MAPA), aminoethylethano-lamine (AEEA), N,N-dimethylethylenediamine (DMEDA) and 3-dimethylaminopropylamine (DMPDA) were added as activators, respectively. Under a total amine concentration of 40%, the chemical absorbent was configured with mass ratios of main agent to activator of 1∶1, 2∶1 and 3∶1, respectively. The absorption rate, regeneration rate and circulation capacity of different absorbers were determined by comparing bubble absorption and oil bath regeneration experiments.ResultsMDEA-EDA system has the best absorption property when the mass ratio of MDEA to EDA is 1∶1. The MDEA-DMEDA system has the best regeneration property when the mass ratio of MDEA to DMEDA is 2∶1, with a circulation capacity reaching 1.7 mol/kg. The overall properties of MDEA-AEEA system are optimized when the mass ratio of MDEA to AEEA is 1∶1, with a cycle capacity reaching 1.49 mol/kg.ConclusionsThe research results can provide a theoretical basis for the formulation optimization of mixed amine solutions in industry.

Copyright of Power Generation Technology is the property of Power Generation Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The wetting property to different oil of cotton fibers which come from different regions of China was studied. The surface adsorption characteristics of cotton fibers were characterized. It is found that the oleophilic and hydrophobic properties of all the raw cotton fibers are fantastic and the average static contact angle of cotton fibers to water is 135.36°, but it is less than 51° to different oil such as engine oil, waste oil and salad oil. In the dynamic spreading process, the droplets of water formed on the surface of cotton fibers and the contact angles of all the cotton fibers to water is not changing with time while the oil liquids were quickly and completely spread out almost in 2000 ms. The speed of spreading is closely relevant with the viscosity of oil and the higher oil viscosity, the slower wetting velocity. The contact angles of cotton fibers come from different regions to the same oil liquid had little changes, thus the adsorption velocity difference of cotton fibers to engine oil, waste oil and salad oil was not significant, respectively.

Superabsorbent polymers (SAPs) have attracted tremendous attention recently, with researchers noting that their high water absorbability is valuable for various applications, especially in agricultural contexts. Two types of materials can be used to produce SAPs: Fossil‐based (which are harmful to the environment) and bio‐based (which are significantly more environmentally friendly, given their biodegradability and minimal toxic side effects). Although bio‐based SAPs are preferable for environmental reasons, their synthesis tends to be time consuming and labour intensive, while their absorption capacity (AC) can be far below expectations. To address these problems, a novel, eco‐friendly, cellulose‐based superabsorbent polymer (Cellulo‐SAP) was developed in this study through facile preparation via free radical synthesis using modified cellulose. Then, the absorbency, thermal/pH stability, reusability, and biodegradability of Cellulo‐SAP were evaluated. This new polymer demonstrated reusability as a water reservoir, in addition to high thermal and pH stability. More importantly, Cellulo‐SAP achieved an AC of 475 g/g and exhibited superior biodegradability compared to a commercial, fossil‐based SAP. Accordingly, these results prove that Cellulo‐SAP can be used in agriculture as an effective alternative to fossil‐based SAPs. [ABSTRACT FROM AUTHOR]

This work evaluates the application effect and mechanism of superplasticizers (SPs) in alkali-activated materials (AAM). Naphthalene superplasticizer (NS), aliphatic superplasticizer (AS) and polycarboxylate superplasticizer (PS) were selected, and three aluminosilicate precursors and two alkali activators were used to prepare AAM. The results showed that all three SPs cannot effectively improve the fluidity of AAM paste, but have certain plasticizing effect in AAM mortar. Both the molecular structure and absorption property of the three SPs changed in AAM. The activator NaOH had more serious damage to the molecular structure of SPs, while the competitive adsorption of Na2SiO3 to SPs was more intense. The intrinsic viscosity and infrared spectrum characteristic peak of AS were relatively stable, followed by NS, while the PS molecule was the most unstable in the alkaline environment. For precursors, metakaolin had the highest surface adsorption energy, resulting in its winding with the incomplete SPs molecule damaged by activator and a decrease in paste fluidity. For fly ash with a smooth surface and low calcium content, its absorption capacity to SPs was the worst, having the smallest adsorption layer thickness of SPs and |ζ| potential. Although the slag could form effective absorption with the anion of SPs, there was significant competition for calcium ions between the SPs and activators, causing the detachment of SPs from the slag surface. [ABSTRACT FROM AUTHOR]

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The improvement of gel strength and absorption properties through the surface-crosslinking of superabsorbent polymers (SAPs) is essential for sanitary industry applications. We prepared core-SAP via aqueous solution copolymerization, and then surface-crosslinked the core-SAP under various conditions. The structure of the SAP was characterized using Fourier transform infrared (FT-IR) spectroscopy. Central composite design (CCD) of response surface methodology (RSM) has been applied to determine the optimum surface-crosslinking conditions such as surface-crosslinker content, reaction temperature, and reaction time. The optimal surface-crosslinking conditions were identified at a surface-crosslinker content of 2.22 mol%, reaction temperature of 160 °C, and reaction time of 8.7 min. The surface-crosslinked SAP showed excellent absorbency under load of 50 g/g with a permeability of 50 s. Other absorption properties were also evaluated by measuring the free absorbency and centrifuge retention capacity in saline solution. [ABSTRACT FROM AUTHOR]

Ordered by set inclusion, the retracts of a lattice L together with the empty set form a bounded poset R e t (L) . By a grid we mean the direct product of two non-singleton finite chains. We prove that if G is a grid, then R e t (G) is a lattice. We determine the number of elements of R e t (G) . Some easy properties of retracts, retractions, and their kernels called retraction congruences of (mainly distributive) lattices are found. Also, we present several examples, including a 12-element modular lattice M such that R e t (M) is not a lattice. [ABSTRACT FROM AUTHOR]

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Orthorhombic phase α-BiNbO4 : Eu3+ and triclinic phase β-BiNbO4 : Eu3+ were synthesized by solid-state reaction method. Their structure and fluorescence properties were studied by X-ray diffractometer (XRD), Raman spectra, absorption spectra and luminescence spectra. Results indicate that pure α-BiNbO4 were successfully synthesized at 900 °C, while triclinic phase β-BiNbO4 obtained at 1 200 °C. The band structure of both structure BiNbO4 was studied using the first principle theory and absorption spectra. The optical band gap obtained for α-BiNbO4 and β-BiNbO4 are 2. 69 eV and 2. 96 eV respectively, in agreement with the theoretical result of 2. 640 eV and 3. 032 eV. After Eu3+ doping, theirs band gap blue shifts to 2. 89 eV and 3. 05 eV respectively, which effectively change their optical response range. The main emission peaks are from 5D0→7F2 transition of Eu3+ for both structural BiNbO4 :Eu, centerted at 615 nm and 611 nm respectively. But the emission intensity of β-BiNbO4 :Eu sample is much higher, and its luminescence intensity ratio between 5D0→ 7F2 and 5D0→7F1 transitions is much higher. For Er3+ doping, upconversion emission is observed for both structures excited at 980 nm. The upconversion emission intensity of β-BiNbO4 : Er sample is almost 40 times higher than that of α-BiNbO4 : Er sample. This results indicate that β-BiNbO4 is more suitable as the host material of rare earth ions doping phosphor. [ABSTRACT FROM AUTHOR]

Orthorhombic phase α-BiNbO4 : Eu3+ and triclinic phase β-BiNbO4 : Eu3+ were synthesized by solid-state reaction method. Their structure and fluorescence properties were studied by X-ray diffractometer (XRD), Raman spectra, absorption spectra and luminescence spectra. Results indicate that pure α-BiNbO4 were successfully synthesized at 900 °C, while triclinic phase β-BiNbO4 obtained at 1 200 °C. The band structure of both structure BiNbO4 was studied using the first principle theory and absorption spectra. The optical band gap obtained for α-BiNbO4 and β-BiNbO4 are 2. 69 eV and 2. 96 eV respectively, in agreement with the theoretical result of 2. 640 eV and 3. 032 eV. After Eu3+ doping, theirs band gap blue shifts to 2. 89 eV and 3. 05 eV respectively, which effectively change their optical response range. The main emission peaks are from 5D0→7F2 transition of Eu3+ for both structural BiNbO4 :Eu, centerted at 615 nm and 611 nm respectively. But the emission intensity of β-BiNbO4 :Eu sample is much higher, and its luminescence intensity ratio between 5D0→ 7F2 and 5D0→7F1 transitions is much higher. For Er3+ doping, upconversion emission is observed for both structures excited at 980 nm. The upconversion emission intensity of β-BiNbO4 : Er sample is almost 40 times higher than that of α-BiNbO4 : Er sample. This results indicate that β-BiNbO4 is more suitable as the host material of rare earth ions doping phosphor. [ABSTRACT FROM AUTHOR]

The improvement of gel strength and absorption properties through the surface-crosslinking of superabsorbent polymers (SAPs) is essential for sanitary industry applications. We prepared core-SAP via aqueous solution copolymerization, and then surface-crosslinked the core-SAP under various conditions. The structure of the SAP was characterized using Fourier transform infrared (FT-IR) spectroscopy. Central composite design (CCD) of response surface methodology (RSM) has been applied to determine the optimum surface-crosslinking conditions such as surface-crosslinker content, reaction temperature, and reaction time. The optimal surface-crosslinking conditions were identified at a surface-crosslinker content of 2.22 mol%, reaction temperature of 160 °C, and reaction time of 8.7 min. The surface-crosslinked SAP showed excellent absorbency under load of 50 g/g with a permeability of 50 s. Other absorption properties were also evaluated by measuring the free absorbency and centrifuge retention capacity in saline solution.

In the last several decades, significant efforts have been devoted to two-dimensional (2D) materials on account of their optical properties that have numerous applications in the optoelectronic world in the range of light-emitting diodes, optical sensors, solar energy conversion, photo-electrochemical cells, photovoltaic solar cells, and even the biomedical sector. First, we provide an outline of linear optical properties of 2D materials such as graphene, TMDs, h-BN, MXenes, perovskite oxide, and metal-organic framework. Then, we discuss the optoelectronic properties of the 2D materials. Along with these, we also highlight the important efforts in developing 2D optical materials with intensive emission properties at a broad wavelength from ultraviolet to near-infrared. The origin of this tunable emission has been discussed decoratively. Thickness and layer-dependent optical properties have been highlighted and are explained through surface defects, strain, vacancy, doping, and dangling bonds emerging due to structural change in the material. The linear and nonlinear optical properties in 2D MXene and perovskite oxides are also impressive due to their potential applications in next-generation devices with excellent optical sensitivity. Finally, technological innovations, challenges, and possible tuning of defects and imperfections in the 2D lattice are discussed.

Carbon nanotubes (CNTs) can create a larger specific surface area and space conductive network with its in-situ growth on the carbon fiber (CF) felt, which have the potential to be an excellent electromagnetic (EM) wave absorbing materials. Herein, we reported a fast and effective induction heating method to in-situ grow CNTs on the CF matrix to prepare carbon nanotubes/carbon fiber (CNTs/CF) composites. The CNTs/CF composites prepared by rapid induction heating have light weight and excellent flexibility. Due to the dense space conductive network formed by CNTs, the EM wave absorbing properties of CNTs/CF composite features 1% filling amount, thin absorption thickness, and width absorption bandwidth. The minimum reflection loss (RL) and peak location can be tailored by controlling the dopant ratio of ferrocene, range from −44.46 dB at 14.16 GHz (the effective bandwidth below −10 dB was achieved in a wide range from 10.48 to 17.92 GHz at the thickness of 3 mm) to −40.615 dB at 5.36 GHz (the bandwidth below −10 dB is narrowed from 4.80 to 6.24 GHz at the thickness of 4.7 mm). Due to its extremely light weight, excellent EM wave absorbing property and flexibility, CNTs/CF composites have the potential to be used in the chip-shielding field. Image 1 • The innovative induction heating was proposed to prepare CNTs/CF composite. • EM wave absorption performance can be controlled by adjusting the density of CNTs. • The excellent EM wave absorption performance can be obtained with a filling amount about 1%. • The EM wave loss mechanism is discussed in detail. [ABSTRACT FROM AUTHOR]

In terms of optical properties, most of the foods are turbid. The ability of light to penetrate a turbid material mainly depends on its absorption and scattering properties. Understanding the absorption and scattering properties of food is not only helpful to understand their chemical and physical properties, but also useful to optimize and develop effective devices for quality determination of food. To provide information for further studies on absorption and scattering properties of turbid food, the measurement techniques, such as integrating sphere, spatially resolved, frequency-domain, and time-resolved spectroscopes, and calculation algorithms, such as inverse adding double, Monte Carlo, and diffuse approximation, on obtaining absorption and scattering properties over the visible and near-infrared wavelength range were reviewed. The characteristics of these methods as well as the future trend on studying absorption and scattering properties of turbid food were also presented. [ABSTRACT FROM AUTHOR]

The impact of mesoscale eddies on phytoplankton communities attracts considerable research attention because phytoplankton play numerous roles in marine ecosystems. Using remote sensing techniques, this study considered a synoptic relationship between phytoplankton size structure, which is a determinant of energy transfer efficiency in marine ecosystems, and mesoscale eddies, which are ubiquitous ocean features. We found clear spatial variation in the impacts of mesoscale eddies on phytoplankton size structure; phytoplankton communities with larger cell sizes were supported by anticyclonic eddies in oligotrophic regions and by cyclonic eddies in eutrophic regions. Differences in the phytoplankton size structure within these two types of mesoscale eddies became greater, accompanied by interannual trends in the phytoplankton size structure for 2003–2014. Our findings are the first to demonstrate the important linkage between mesoscale eddies and phytoplankton size structure on a global scale; this new knowledge might help better predict variability in marine ecosystems. Plain Language Summary: Mesoscale eddies are ubiquitous ocean features and they play a significant role in phytoplankton dynamics. This study used satellite remote sensing techniques to examine the impact of mesoscale eddies on phytoplankton size structure, an important factor of marine ecosystems. We found clear regional and temporal variations in the impacts of two types of mesoscale eddies: communities of larger‐sized phytoplankton were observed in anticyclonic eddies in oligotrophic regions and in cyclonic eddies in eutrophic regions, and differences in the phytoplankton size structure inside these two eddy types increased during the period 2003–2014. Our findings are the first to demonstrate the important linkage between the cell‐size composition of phytoplankton communities and mesoscale eddies on a global scale; this new knowledge might help us to better predict variability in marine ecosystems both now and in the future. Key Points: This study presents the first findings on the linkage between phytoplankton size and mesoscale eddies on a global scalePhytoplankton communities with larger cell sizes were supported by anticyclonic (cyclonic) eddies in oligotrophic (eutrophic) regionsThese differences in phytoplankton size structure between two types of mesoscale eddies became greater over the 2003–2014 time period [ABSTRACT FROM AUTHOR]

In this article, smoke suppression of Si-Al mesoporous structure on medium density fiberboard (MDF) was investigated by cone calorimeter test (CCT), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and fourier transform infrared spectrometry (FTIR). The CCT results show that the Si-Al mesoporous structure can effectively decrease heat release rate (HRR), total heat release (THR), smoke production rate (SPR), total smoke production (TSP), smoke rate (SR), CO and CO 2 concentration, etc. Particularly, the SR curves of MDF present that Si-Al mesoporous structure are considered to be a filter, which can net the solid particles and volatile flammable components in the smoke and fix onto wood fiber. Remarkably, the CO and CO 2 concentration curves of MDF indicate that the Si-Al mesoporous structure has an excellent adsorption property, which can rapidly absorb CO and CO 2 that generated in wood combustion process. On the other hand, the FTIR and TGA results reveal that the Si-Al mesoporous structure can significantly improve the structure of char residue. [ABSTRACT FROM AUTHOR]

The effects of Co 2 O 3 addition on the electromagnetic properties of NiCuZn ferrite were investigated, by considering the variation of complex permeability, complex permittivity and quasi-microwave absorption property in the 1–1000 MHz frequency range. Results show that the introduction of Co 3+ ions in NiCuZn ferrite leads to the marked shifting of magnetic resonance towards high-frequency and a slight increase of the permittivity. These Co-related effects enhance the maximum reflection loss in NiCuZn ferrite to reach −55.1 dB with its absorption bandwidth being tunable in the frequency range 480–1000 MHz, which provides a potential absorber for the anti-electromagnetic interference applications in electronic industry. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Eight newly synthesized disazo disperse dyes containing benzothiazole and pyrazole moieties were prepared by diazotization of 2-aminobenzothiazole, coupling with 3-aminocrotononitrile as active methylene, cyclization reactions with hydrazine hydrate and phenyl hydrazine, diazotization again and finally coupling with dimedone, dioxane, 1-methyl imidazole and 2-methyl imidazole, respectively. Their structures were characterized with spectroscopic methods (FT-IR, H-NMR, C-NMR) and solvatochromic properties were studied with UV-Vis spectroscopy in different solvents. Tautomeric structures of synthesized dyes were also examined in detail. [ABSTRACT FROM AUTHOR]

In this paper, the flower-like FeCo/ZnO composites were successfully firstly prepared by a two-step method, and their microstructures and microwave absorbing properties were characterized. The results show that with an increase of temperature, the content of ZnO loaded on a FeCo/ZnO composite surface was increased. The optimal reflection loss (RL) value can be reached around −53.81 dB at 9.8 GHz, which is obviously superior to results of previous studies and reports, and its effective bandwidth (RL < −10 dB) is 3.8 GHz in the frequency range of 8.7−11.8 GHz with a matching thickness of 1.9 mm. We considered that a large number of lamellar and rod-like ZnO loaded on nano-FeCo single-phase solid solution by two-step method can significantly improve the electromagnetic wave absorption properties.

We report herein the synthesis of a novel hexagonal boron nitride nanocrystal/graphite nanoflake ( h -BNNC/GNF) composite through a wet-chemistry coating of graphite nanoflakes and subsequent in-situ thermal treatment process. The characterization results of X-ray diffraction, scanning electron microscope, transmission electron microscope, energy dispersive X-ray spectrum, and X-ray photoelectron spectroscopy demonstrate that h -BNNCs with diameter of tens of nanometers are highly crystallized and anchored on the surfaces of graphite nanoflakes without obvious aggregation. The minimum reflection loss (RL) value of the h -BNNC/GNF based absorbers could reach −32.38 dB (>99.99% attenuation) with the absorber thickness of 2.0 mm. This result is superior to the other graphite based and some dielectric loss microwave absorption materials recently reported. Moreover, the frequency range where the RL is less than −10 dB is 3.49–17.28 GHz with the corresponding thickness of 5.0–1.5 mm. This reveals a better electromagnetic microwave absorption performance of h -BNNC/GNFs from the X-band to the K u -band. The remarkable enhancement of the electromagnetic microwave absorption properties of h -BNNC/GNFs can be assigned to the increase of multiple scattering, interface polarization as well as the improvement of the electromagnetic impedance matching of graphite nanoflakes after being coated with h -BNNCs. [ABSTRACT FROM AUTHOR]

Ti-based metallic glassy powders were utilized as dealloying precursors and core-shell structured absorbents with metallic glassy particles as core and amorphous metal oxides as shell were synthesized through hydrothermal method. The absorbents exhibited superior adsorption efficiency and capacity for removing toxic Cr 6 + in aqueous solution. In addition, the electromagnetic wave absorption properties were investigated and the absorbents had considerable electromagnetic wave absorbing ability owing to its dielectric loss. This work provides a strategy for fabrication of core-shell particles using facile dealloying of multiple component alloys. [ABSTRACT FROM AUTHOR]

This paper focuses on the honeycomb cores with absorbing coatings, the effective permittivity is predicted and the absorption property is optimized. The correctness of effective results is verified by experimental measurement, numerical simulation and theoretical analysis. When honeycomb cores with absorbing coatings are regarded as layered multi-phase materials, the upper and lower bounds of effective permittivity are calculated by the way of multi-step equivalence. In order to exhibit the dispersion effect, the improved strong fluctuation theory is proposed. In the second part of works, the size optimization is executed to improve absorption property. The optimization problem is defined that the area T which is surrounded by the effective reflectivity curve and the boundary line (R0 = -10 dB) is maximized under the upper bound constraints of reflectivity and volume fraction. The optimal effective reflectivity curve is obtained within the given frequency range. [ABSTRACT FROM AUTHOR]

The seven rhenium (I) tricarbonyl complexes having a general formula fac-[ReBr(CO)3(R1,R2,R3-N^N)] (N^N = imidazo[4,5-f]-1,10-phenanthroline; R1 = tBu, R2 = R3 = H, 1; R1 = CCH, R2 = R3 = H, 2; R1 = tBu, R2 = CCH, R3 = H, 3; R1 = tBu, R2 = R3 = CCH, 4; R1 = tBu, R2 = CH3, R3 = H, 5; R1 = tBu, R2 = R3 = CH3, 6; R1 = tBu, R2 = OCH3, R3 = H, 7) have been investigated theoretically by density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. The different substituted groups on N^N ligand induce changes on the electronic structures and photophysical properties for these complexes. It is found that the introduction of CC decreases the energy level of lowest unoccupied molecular orbital (LUMO) while the introduction of CH3 or OCH3 lead to increase the energy level of LUMO. The order of LUMO energy level rising is in line with the increasing of donating abilities of substituted groups; and the influence of R2 position is greater than that of R1 position on LUMO energy level. The lowest energy absorption bands have changes in the order of 7 < 6 < 5 < 1 < 2 < 3 < 4. These results of electronic affinity (EA), ionization potential (IP), and reorganization energy ( λ) indicate that all of these complexes can be used as electron transporting materials. Moreover, the smallest difference between λelectron and λhole of 4 indicates that it is better to be used as an emitter in the organic light-emitting diodes. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

A bio-absorbent of Fe-CoNiP coated on the diatomite was fabricated by way of electroless plating of CoNiP and subsequent chemical vapor deposition of Fe. The surface morphology and composition of the above-mentioned diatomite particles at different stage were characterized with the scanning electron microscopy and the energy spectrum analysis respectively, and the results showed that the diatomite was successfully coated with CoNoP and Fe (carbony iron). The complex permittivity and permeability of composites filled with the bio-absorbent and paraffin was measured in frequency range of 2–18 GHz, and then the microwave reflection loss (RL) and the shielding effectiveness (SE) were calculated. The results showed that the permittivity and the permeability were both enlarged as Fe films were coated onto the CoNiP-coated diatomite, which was attributed to the excellent electromagnetic property of carbonyl irons. The composites made with the Fe-CoNiP diatomite had a better absorbing property (minimum RL −11.0 dB) as well as the shielding property (maximum SE 5.6 dB) at thickness 2 mm. It indicated the absorption property was mainly due to the attenuation on the microwave, and the Fe-CoNiP diatomite could be an effective absorbent with low-density. [ABSTRACT FROM AUTHOR]

The synthesis, extraction and chromogenic properties of calix[4]arenes, carrying phenylazo and amido groups on theirupperandlowerrims, respectively, are described. Novel azocalix[4]arene amides (1a–d, 2a–d, 3a–d) and some of their telomers (T1a–T1d) have been synthesised and characterised by spectroscopic methods as well as elemental analysis techniques. Compounds1cand2bwere additionally characterised by two-dimensional nuclear magnetic resonance spectroscopic methods. Some of the compounds were examined by absorption spectra using different solvents. The colour changes of the resulting solutions can be observed by the ‘naked eye’. Metal extraction abilities of compounds have been investigated comparatively. Telomer structures of azocalix[n]arenes exhibited higher extraction rates compared to those of their monomers. Products obtained under this study, especially telomers, can be used in the field of ion-selective electrodes. [ABSTRACT FROM AUTHOR]

3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) nanostructures with different morphologies are prepared on glass substrates at different substrate temperature (Ts) in a molecular beam epitaxy (MBE) system. Scanning/transmission/scanning transmission electron microscopy (SEM/TEM/STEM), X-ray diffraction (XRD), selected area electron diffraction (SAED) and nanobeam diffraction (NBD) techniques are employed in the systematical characterizations of the nanostructures. It is found that the PTCDA nanosheets (NSs), nanowires and nanorods are facile to produce at Ts = 350°, 330°C and 240°C, respectively; the continuous films are obtained at 180°C and 50°C. XRD studies indicate that only the α-phase polymorph is formed regardless of the Ts. SAED and NBD results show that the nanowire and NS are single crystalline. The optical properties of the prepared PTCDA nanostructures are also found to be influenced by Ts and are correlated with the crystal quality and size. PTCDA nanowires and NSs exhibit an obvious redshift and broadening in the adsorption spectra, and enhanced emission intensity. The improved optical properties facilitate potential applications of these nanostructures in organic optoelectronic devices. With the transformation from multi-crystalline film to 1D nanostructures, the crystal texture of PTCDA enhances greatly. The improved structural quality leads to a reduced distance between the oppositely charged stacked molecules on the microscopic scale, and thus a favorite formation of the self-trapped charge-transfer (CTST) excitons. Simultaneously, the transition probabilities from the ground state to CT and CTST states are enhanced, while the mixed F-CT states are attenuated with the evolutions of PTCDA morphology. The observed redshift and broadening of the optical adsorption band as well as its intensified emission accompanying the crystalline quality increasing of PTCDA nanostructures suggest potential applications of these nanostructures in relevant organic optoelectronic devices. [ABSTRACT FROM AUTHOR]

During the manufacturing processes of the thin-film transistor liquid-crystal display (TFT-LCD) panel, red, green, and blue (RGB) color filter coatings undergo the layer-adding process which causes the rough surfaces between the layers. The rough surfaces make acquiring an accurate measurement of the optical properties and thickness (n, k, d) much more difficult because the scattering effects occur. The effective layer-included model is considered in determining the (n, k, d) by including effective layers to reside between and above the multilayer (ML). To show the feasibility of the effective layer-included model, we examined the model by fitting the (n, k, d) for different virtual systems which contain different kinds of scatters reside between and above it. Our findings show that the fitted (n, k, d) can be closer to the assumed (n, k, d) by using the effective layer-included model rather than the standard model. Also, the tolerance of initial assigned (n, k, d) regions to obtain the accurate results are investigated. Further, both models are used to determine the (n, k, d) of the fabricated RGB color filter samples. In the experimental measurements, all reflection and transmission signals are measured by utilizing the in-house variable angle spectroscopic ellipsometry (VASE) system. Consequently, the thicknesses determined from effective layer-included model are closer to the thicknesses measured from profilometry (Alpha-step 100). Also, the transmissions under 0 °, 15 °, and 30 ° illuminations calculated from the fitted (n, k, d) through the effective layer-included model are closer to the VASE measurements rather than the standard model for each sample. We conclude that the effective layer-included model can be used to determine the accurate (n, k, d) of RGB color filter coatings with rough surface. [ABSTRACT FROM PUBLISHER]

Abstract: The master alloys of Fe87.5−x Si13.5Cr x (x=0, 4, 8, 12at%) were prepared in vacuum induction melting furnace. Corresponding powder samples were obtained by 60h ball milling of the crushed master alloys, and studied by morphological, microstructural, electromagnetic and microwave absorption tests in the frequency range from 0.5 to 18GHz. The powders were characterized by a particle size less than 1μm and a grain size less than 100nm. In the cases of x≥8, Fe3Si phase with D03-type structure was observed, and the powders became amorphous completely. A crystallization temperature of 685K was found for x=8. Coercivity force and saturation magnetization of the powders decreased with the increasing of Cr content. As an electromagnetic wave absorbing material, the minimum reflectivity was −15.5dB at 8.5GHz and the absorption band was broad for x=8 powders. [Copyright &y& Elsevier]

Abstract: The ground geometries, frontier molecular orbitals, and absorption properties of [Re(CO)3(cpen-dpy)Cl] (cpen-dpy = cyclopenta[b]dipyridine) functionalized with different aromatic ring groups were theoretically studied. The introduction of different moieties insignificantly changed the geometric parameters of the complexes. However, the molecular orbital energy levels of the complexes with aromatic ring groups were strongly affected by the solvent molecules. The lowest lying absorption bands of all complexes had HOMO → LUMO transition configurations that resulted in the ligand-to-ligand charge transfer character. The results showed that all complexes displayed a comparative higher sensitivity within the long wavelength range with stronger oscillator strength, which can be beneficial to more efficient absorption of the solar spectrum. The calculated ionization potential and electron affinity revealed that the balanced transport of electrons and holes of 1 was more accessible, whereas 4 possessed good hole-transfer abilities. [Copyright &y& Elsevier]

The homopolymer of butyl methacrylate was synthesized by suspension polymerization, then the solution for the monomer hydroxyethyl methacrylate (HEMA) and the initiator benzoyl peroxide (BPO) was mixed with the homopolymer, finally the above mixture was made into organic liquids absorptive functional fiber via the method of reactive extrusion-melt spinning. The absorption capacity, gel fraction, remaining ratio and thermal stability of the fiber were investigated. In addition, the morphology of the fiber was observed by field emission scanning electron microscope (FESEM). The results show that with increasing the mass fraction of HEMA in the mixture the spinnability of the mixture gradually becomes poor, and the absorbency for all the fiber samples displays the changing trend of first increase and then decrease with the extension of absorptive time. The gel fraction first increases and then decreases with increasing the mass fraction of HEMA in the mixture, along with the remaining ratio. The fiber is first endowed with high thermal stability as increasing the mass fraction of HEMA, but then the low thermal stability results from the continuous increase of the mass fraction of HEMA. Furthermore, FESEM images reveal that the fiber obtained as the mass fraction of HEMA being equal to 0 wt% has a mono-phase structure as well as smooth and neat cross-section. However, the fiber shows coarser cross-section and multi-phase structure with the increase of the mass fraction of HEMA. [ABSTRACT FROM PUBLISHER]

Abstract: The ground and excited state geometries and frontier molecular orbital, absorption and emission properties of the four transition metal complexes Re(bpy)(CO)3(PEt3)+ (1), Re(bpy)(CO)3(PPh3)+ (2), Re(bpy)(CO)3[P(OEt3)]+ (3) and Re(bpy)(CO)3[P(OPh3)]+ (4) were studied theoretically. The introduction of different phosphine ligands significantly changed the geometric parameters of the complexes. The axial Re–C bond distance was longer than the equatorial Re–C bond distance. The lowest lying absorption bands of 1 and 2 have HOMO→LUMO transition configurations resulting in MLCT/LLCT transition characteristics. The HOMO-1→LUMO transition predominantly contributed to the lowest absorption bands of 3 with MLCT/LLCT characteristics. The absorption band of 4 at 326nm was dominated by HOMO-4→LUMO and HOMO-6→LUMO transitions with mixed MLCT/LLCT characteristics. The phosphorescence emission energies of 1–4 were also calculated and compared with the experimental values. [ABSTRACT FROM AUTHOR]

Cross-linked fluoroalkyl end-capped cooligomers possessing double decker-type aromatic silsesquioxane segments as core units [R-( Ar-SiSQ)-(Co-M)-R] were prepared under mild conditions by the cooligomerizations of fluoroalkanoyl peroxide with the corresponding aromatic silsesquioxane possessing bifunctional vinyl groups ( Ar-SiSQ) and comonomers (Co-M) such as acryloylmorpholine (ACMO), N, N-dimethylacrylamide (DMAA) and N-(1,1-dimethyl-3-oxobutyl)acrylamide (DOBAA). Interestingly, these cross-linked fluorinated cooligomers thus obtained were found to form the nanometer size-controlled nanoparticles with a good dispersibility in a variety of solvents including fluorinated aliphatic solvents. These fluorinated cooligomeric nanoparticles were demonstrated to have red-shifted fluorescent emissions related to the presence of aromatic silsesquioxane segments, compared with that of parent aromatic silsesquioxane, indicating that each aromatic moiety in these nanoparticles can interact effectively with each other through the π-π stacking between the aromatic moieties to afford the red-shifted fluorescent emissions. These fluorinated nanoparticles were also applied to the surface modification of poly(methyl methacrylate) (PMMA) to exhibit not only a good oleophobicity imparted by fluorine but also a fluorescent emission behavior related to aromatic silsesquioxane segments in nanoparticles on the modified PMMA surface. More interestingly, cross-linked R-( Ar-SiSQ)-(DOBAA)-R cooligomeric nanoparticles interacted with fluorescein to give the corresponding fluorinated cooligomeric particles/fluorescein nanocomposites in methanol. These fluorinated fluorescein nanocomposites were found to afford an extraordinarily enhanced light absorption ( λ = 441 nm), compared with that of fluoroalkyl end-capped DOBAA oligomer [R-(DOBAA)-R] possessing no aromatic silsesquioxane segments. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The temperature of a solar cell will increase when it is exposed to the sunlight, which results in variations of optical parameters and thermal expansion coefficient of the cell, thus affecting its spectral absorption feature. This paper is aimed to investigate the effects of temperature on the absorption property of solar cells with micro-structured surfaces. By taking hemispherical, cylindrical and spherical surfaces as models, numerical computation is conducted to obtain spectral distribution of absorptance of such surfaces with different structural parameters by means of the finite difference time domain (FDTD) method. Furthermore, the effects of material properties and structural period on the absorption property are also investigated. [ABSTRACT FROM AUTHOR]

Hybrid MnZn/NiZn/PVC polymer composite materials have been prepared using a dry low-temperature hot-pressing process and the influence of particle size, concentration, and the fraction ratio of the dual MnZnINiZn ferrite ifiler on their complex permeability μ= μ'–j μ" and electromagnetic wave (EM-wave) absorbing properties were investigated within the frequency range of 1-3000 MHz. The observed frequency dispersion of permeability was of a relaxation type and caused by a resonance of vibrating domain walls and a natural ferromagnetic resonance of precessing magnetic moments in domains. The complex permeability and resonance frequency fres of hybrid composites have been affected mainly by changes in concentration and fraction ratio of ferrite filler: the μ' at low frequency decreased and fres shifted towards the higher frequency region with the decrease of ferrite concentration and with the configuration change from the MnZn/PVC composite to NiZn/PVC one. Measured values of complex permeability were used to determine the return loss RL using a model of a single-layered EM-wave absorber backed by a perfect conductor. In the designed single layer absorbers, the RL as well as the matching frequency fm, matching thickness dm, bandwidth Δf for RL ⩽ -20 dB, and the minimum of return loss (RL)min seem to be strongly dependent on particle size, concentration, and the fraction ratio of the dual MnZn/NiZn ferrite filler. [ABSTRACT FROM AUTHOR]

Based on the sheath-core bicomponent composite fibers with modified polystyrene (PS) and the modified polypropylene (PP), composite fibers obtained were further cross-linked and sulphonated with chlorosulphonic acid to produce strong acidic cation ion exchange fibers. The structures of the fibers obtained were characterized using Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) etc. The optimal technology of the fibers obtained is discussed. The static absorption capacity of the sheath-core bicomponent composite cation exchange fibers for Zn, Cu was determined. The absorption kinetics and major factors affecting the absorption capacities of Zn, Cu were studied, and its chemical stability and regenerating properties were probed. The results suggest that cation exchange fibers with better mechanical properties and higher exchange capability were obtained. Moreover, this type of ion exchange fiber has good absorption properties and working stability to various metal ions. Hence, they have higher practicability. [ABSTRACT FROM AUTHOR]

Abstract: Ordered macroporous anatase titania films doped with Ag nanoparticles (NPs) were synthesized by infiltrating titania sol into the interstitial voids of polystyrene colloidal sphere templates, removing the templates, immersing the films in a silver nitrate solution, and subsequently reducing in hydrogen atmosphere. Ag NPs were distributed uniformly within the macropores of the anatase titania film. Both the macroporous titania films doped with Ag NPs and those without doping have a blue-shift compared with that of the sol–gel derived titania film. Except for the plasma resonance absorption of Ag NPs, the macroporous titania film doped with Ag NPs also has a red-shift compared with the undoped sample. The macroporous titania film doped with Ag NPs have potential applications in the fields of optics, gas sensors, and catalysis. [Copyright &y& Elsevier]

A series of novel Dy3+/Eu3+/Sm3+-activated InNbTiO 6 phosphors have been prepared by conventional solid state reaction method. Based on the structure refinement, RE3+ ions are preferred to occupy the site of In3+ (2 e) in the wolframite-type host lattice. According to their UV–visible diffusion reflectance spectra, the band gap and absorption property of un-doped InNbTiO 6 sample can be tuned by the dopants. Under UV–visible light excitation, Dy3+/Eu3+/Sm3+ activators in this matrix mainly show emission lines originating from their characteristic f→f transitions. The optimal excitation and emission wavelength are 385 nm and 581 nm for Dy3+, 394 nm and 616 nm for Eu3+, 406 nm and 615 nm for Sm3+. Concentration quenching occurs at 0.06 for Dy3+, 0.06 for Eu3+, and 0.04 for Sm3+, ascribed to resonant q-q, q-q, and d-q interactions, respectively. The luminescence lifetimes are determined to be 0.13, 0.50, and 0.50 ms for InNbTiO 6 :0.06Dy3+, InNbTiO 6 :0.06Eu3+, and InNbTiO 6 :0.04Sm3+, respectively. The Dy3+, Eu3+, and Sm3+ doped phosphors exhibited yellowish-white, red, and orange-red luminescence, respectively. The quantum yields and thermal stability of representative phosphors have been investigated. Present work shows that these new phosphors are promising for application in UV-LED solid-state lighting devices. New yellowish-white, red, and orange-red emitting phosphors have been fabricated using the InNbTiO 6 matrix. Image 1 • The yellowish-white, red, and orange-red emitting phosphors have been fabricated using the InNbTiO 6 matrix. • These activators occupy the site of In3+ (2 e) in the wolframite-type host lattice. • Multipolar interactions are responsible for the concentration quenching effect of Dy3+/Eu3+/Sm3+ activators. • PL of representative phosphors have shed light on the effect of Ti4+ ions to luminescent behavior in the same structure. • The thermal stability of InNbTiO 6 :Sm3+ phosphors is favorable under the excitation of UV-visible light. [ABSTRACT FROM AUTHOR]

In this paper, the flower-like FeCo/ZnO composites were successfully firstly prepared by a two-step method, and their microstructures and microwave absorbing properties were characterized. The results show that with an increase of temperature, the content of ZnO loaded on a FeCo/ZnO composite surface was increased. The optimal reflection loss (RL) value can be reached around −53.81 dB at 9.8 GHz, which is obviously superior to results of previous studies and reports, and its effective bandwidth (RL < −10 dB) is 3.8 GHz in the frequency range of 8.7–11.8 GHz with a matching thickness of 1.9 mm. We considered that a large number of lamellar and rod-like ZnO loaded on nano-FeCo single-phase solid solution by two-step method can significantly improve the electromagnetic wave absorption properties. [ABSTRACT FROM AUTHOR]

As an emerging promising photovoltaic absorber material, GeSe has attracted significant interest recently due to its simple binary composition, attractive optical and electrical properties as well as earth‐abundant and low‐toxic constituents. However, no systematic study on the absorption property tuning of GeSe has been reported. Here, first it is shown that the crystallization temperature of amorphous GeSe is about 330 °C through differential thermal analysis and temperature‐dependent X‐ray diffraction. Next, GeSe films with tunable absorption property in the range of 1.79–1.14 eV are fabricated by annealing amorphous GeSe films at different temperatures. Finally, through the combined analysis of bandgaps measured by transmission spectroscopy and nanosheet thickness characterized by cross‐sectional high‐resolution transmission electron microscopy, the blue shift of bandgap with decreasing thickness of nanosheets has been attributed to the quantum confinement effect. Such continuously tunable absorption property of GeSe films makes it more useful for further optoelectronics. A controllable absorption property tuning of GeSe films in the range of 1.79–1.14 eV through annealing treatment of amorphous GeSe films has been demonstrated. Such continuously tunable absorption property of GeSe films makes it more useful for further optoelectronics. [ABSTRACT FROM AUTHOR]