| 1. |
- Fang, Bo, et al.
(författare)
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Dual-Channel Neural Network for Atrial Fibrillation Detection From a Single Lead ECG Wave
- 2023
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Ingår i: IEEE journal of biomedical and health informatics. - : Institute of Electrical and Electronics Engineers (IEEE). - 2168-2194 .- 2168-2208. ; 27:5, s. 2296-2305
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Tidskriftsartikel (refereegranskat)abstract
- With the dramatic progress of wearable devices, continuous collection of single lead ECG wave is able to be implemented in a comfortable fashion. Data mining on single lead ECG wave is therefore attracting increasing attention, where atrial fibrillation (AF) detection is a hot topic. In this paper, we propose a dual-channel neural network for AF detection from a single lead ECG wave. Two primary phases are included, the data preprocessing part followed by a dual-channel neural network. A two-stage denoising procedure is developed for data preprocessing, so as to tackle the high noise and disturbance which generally resides in the ECG wave collected by wearable devices. Then the time-frequency spectrum and Poincare plot of the denoised ECG signal are imported into the developed dual-channel neural network for feature extraction and AF detection. On the 2017 PhysioNet/CinC Challenge database, the F1 values were 0.83, 0.90, and 0.75 for AF rhythm and normal rhythm, and other rhythm, respectively. The results well validate the effectiveness of the proposed method for AF detection from a single lead ECG wave, and also indicate its performance advantages over some state-of-the-art counterparts.
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| 2. |
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| 3. |
- Wang, JunXin, et al.
(författare)
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General Method for Determining Light Scattering and Absorption of Nanoparticle Composites
- 2019
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Ingår i: Advanced Optical Materials. - : Wiley-VCH Verlagsgesellschaft. - 2162-7568 .- 2195-1071. ; 7:4
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Tidskriftsartikel (refereegranskat)abstract
- Scattering and absorption from nanoparticles are of major importance in optical research as well as in a range of applications. The Kubelka–Munk two-flux radiative transfer model gives a simple description of light scattering in nanoparticle composite materials, but inversion of experimental transmittance and reflectance data to obtain backscattering and absorption coefficients remains challenging. Here, a general method for evaluating these parameters from transmittance and reflectance spectra, combined with spectral angle resolved light scattering measurements is developed. The angular dependence is approximatedby an extension of the empirical Reynolds–McCormick phase function, which is fitted to the experimental angle resolved light scattering data. This approach is verified by measurements on three typical nanoparticle/polymer composites containing plasmonic Au, ferromagnetic Fe3O4, and dielectric TiO2 particles. An approximation to the angular scattering pattern is further demonstrated, which can be applied to obtain the optical parameters using only reflectance and transmittance data, in cases where angle-resolved measurements are not available. These results can be extended to a wide range of isotropic, anisotropic, and multiple scattering systems, and will be highly useful in the fields of light scattering coatings/metamaterials, UV-shielding films, displays, absorption/scattering layers in solar cells and biological scatterers.
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| 4. |
- Barrios, David, et al.
(författare)
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Light Scattering Parameters of Polymer Dispersed Liquid Crystals Obtained by Inversion of Experimental Data
- 2022
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Ingår i: Proceedings of the Bremen Zoom Workshop on Light Scattering 2022. - : Leibniz Institute for Materials Engineering IWT. ; , s. 8-11
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Polymer Dispersed Liquid Crystal (PDLC) devices are electrically controlled smart windows, that switch from a translucent milky appearance (off state) to a transparent clear appearance (on state). We have studied the intrinsic and extrinsic scattering and absorption coefficients obtained by inversion of spectrophotometric transmittance and reflectance data. The inversion procedure uses two flux and four flux models and similar approximations for the average crossing parameter (ACP) as in our previous workon suspended particle devices [1]. Good fits are obtained, but the ACP approximation was found to be inconsistent with fitted parameters.
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| 5. |
- He, Tongyue, et al.
(författare)
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Toward Wearable Sensors : Advances, Trends, and Challenges
- 2023
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Ingår i: ACM Computing Surveys. - : Association for Computing Machinery (ACM). - 0360-0300 .- 1557-7341. ; 55:14S
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Forskningsöversikt (refereegranskat)abstract
- Sensors suitable for wearable devices have many special characteristics compared to other sensors, such as stability, sensitivity, sensor volume, biocompatibility, and so on. With the development of wearable technology, amazing wearable sensors have attracted a lot of attention, and some researchers have done a large number of technology explorations and reviews. However, previous surveys generally were concerned with a specified application and comprehensively reviewed the computing techniques for the signals required by this application, as well as how computing can promote data processing. There is a gap in the opposite direction, i.e., the fundamental data source actively stimulates application rather than from the application to the data, and computing promotes the acquisition of data rather than data processing. To fill this gap, starting with different parts of the body as the source of signal, the fundamental data sources that can be obtained and detected are explored by combining the three sensing principles, as well as discussing and analyzing the existing and potential applications of machine learning in simplifying sensor designs and the fabrication of sensors.
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| 6. |
- Jacobsson, Jesper, 1984-, et al.
(författare)
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An open-access database and analysis tool for perovskite solar cells based on the FAIR data principles
- 2022
-
Ingår i: Nature Energy. - : Springer Nature. - 2058-7546. ; 7:1, s. 107-115
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Tidskriftsartikel (refereegranskat)abstract
- Large datasets are now ubiquitous as technology enables higher-throughput experiments, but rarely can a research field truly benefit from the research data generated due to inconsistent formatting, undocumented storage or improper dissemination. Here we extract all the meaningful device data from peer-reviewed papers on metal-halide perovskite solar cells published so far and make them available in a database. We collect data from over 42,400 photovoltaic devices with up to 100 parameters per device. We then develop open-source and accessible procedures to analyse the data, providing examples of insights that can be gleaned from the analysis of a large dataset. The database, graphics and analysis tools are made available to the community and will continue to evolve as an open-source initiative. This approach of extensively capturing the progress of an entire field, including sorting, interactive exploration and graphical representation of the data, will be applicable to many fields in materials science, engineering and biosciences.
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| 7. |
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| 8. |
- Niklasson, Gunnar A., 1953-, et al.
(författare)
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Inversion of Light Scattering Experiments by Using the Four-Flux Theory
- 2022
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Ingår i: Proceedings of the Bremen Zoom Workshop on Light Scattering 2022. - : Leibniz Institute for Materials Engineering IWT. ; , s. 40-43
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We discuss methods to use the four-flux theory to obtain parameters characterizing light scattering in particulate materials, by inversion of spectrophotometric transmittance and reflectance data. Specifically, we assess the possibility to simplify the inversion procedure by using approximations for some of the parameters of this theory, in particular the forward scattering ratios (FSR’s) and average pathlength parameters (APP’s), that are related to the angular distribution of the radiation field in the material. We also consider the possibility to obtain information on these parameters by angle resolved scattering measurements.
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| 9. |
- Niklasson, Gunnar A., 1953-, et al.
(författare)
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Optics of sunscreen lotions : Preliminary results on scattering and absorption coefficients
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Sunscreen lotions are used to protect the skin from damage due to solar ultraviolet (UV) radiation. The active UV-blocking components can be organic molecules or inorganic particles, for example TiO2. While both in-vivo and in-vitro methods exist for assessing the protective capacity of sunscreens, their basic optical properties have received little attention. In this paper we take the first steps to address this issue by presenting a method to obtain spectra of absorption and scattering coefficients of a sunscreen by analysis of experimental transmittance and reflectance spectra. We model the optical properties of the sunscreen by two-flux theory, develop approximate expressions for interface reflection coefficients and obtain the remaining optical parameters by fitting the two-flux theory to measurements. We analyze spectrophotometric reflectance and transmittance spectra of experimental narrow band UV blocking materials based on mesoporous magnesium carbonate – TiO2 mixtures, as well as some commercial sunscreens. Our method is demonstrated in vitro using quartz substrates and is further used to model in vivo measurements on the upside of the hand of one of the authors. The obtained absorption and scattering coefficient spectra give information on the relative contributions of these processes to the UV-blocking effect as well as the scattering of visible light responsible for the whitening of the skin upon application of a sunscreen lotion. Our analysis method may be useful for computational optimization of novel sunscreen formulations as well as for the development of in-vivo test methods.
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| 10. |
- Niklasson, Gunnar, 1953-, et al.
(författare)
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Light Scattering Parameters by Inversion of Experimental Data: The Case of Sunscreen Lotions
- 2021
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Ingår i: Proceedings of the Bremen Zoom Workshop on Light Scattering 2021. - Bremen : Leibniz Institute for Materials Engineering IWT. ; , s. 16-19
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Konferensbidrag (refereegranskat)abstract
- We present a method to obtain absorption and backscattering coefficients of a light scattering material and apply it to the technologically important case of sunscreen lotions. While both in-vivo and in-vitro methods exist for assessing the ultraviolet (UV) protective capacity of sun-screens, their basic optical properties have previously received little attention. We model the light scattering properties by two-flux theory and invert spectrophotometric total transmittance and reflectance measurements to obtain backscattering and absorption coefficient spectra.
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| 11. |
- Qu, Hui-Ying, et al.
(författare)
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Multicolored absorbing nickel oxide films based on anodic electrochromism and structural coloration
- 2021
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 129:12
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Tidskriftsartikel (refereegranskat)abstract
- Inorganic electrochromic materials are promising for applications in color-based chromogenic technologies. Limited color control in these materials has, however, hitherto hampered their applications. Here, we show that multicolored nickel oxide (NiO) films can be obtained due to the combined effect of the intrinsic color of NiO and the structural color of the inverse opal structures by tailoring anodic oxide NiO films, exhibiting an absorption tail in the visible region into three-dimensional ordered macroporous inverse opal photonic bandgap structures. Various colors were achieved by the synergistic mechanism of structural and electrochromic coloration, thus realizing a wide spectrum of blue, green, yellow, orange, and brown colors depending on pore size, wall thickness, and viewing angle. Importantly, it is shown that the depth of color can be varied by applying an external potential. The electrochromic coloring of the inverse opal NiO films is found to be very different from the typical optical switching of non-structural NiO films. Thus, our work brings insights into the development of inorganic colored electrochromic materials.
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| 12. |
- Vargas, William E., et al.
(författare)
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Effective backscattering and absorption coefficients of light diffusing materials retrieved from reflectance and transmittance spectra of diffuse radiation
- 2021
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Ingår i: Journal of Modern Optics. - : Informa UK Limited. - 0950-0340 .- 1362-3044. ; 68:12, s. 605-623
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Tidskriftsartikel (refereegranskat)abstract
- Solutions of the differential equations for the diffuse components of the four-flux model are obtained, including explicit expressions for the collimated-diffuse and diffuse-diffuse reflectance and transmittance for an optical three-layer system. We establish a method to invert collimated-diffuse reflectance and transmittance in order to obtain the spectral variation of all average pathlength parameters and forward scattering ratios, by applying a spectral simulated annealing method. The inversion procedure was tested with synthetic collimated-diffuse reflectance and transmittance spectra and showed very good convergence. Subsequently, the method was applied to measured spectra of a light scattering and absorbing medium containing TiO2 particles in a low-absorbing matrix, which was enclosed between two glass slides. Hence the present paper, together with our previous one, wherein we inverted collimated-collimated reflectance and transmittance spectra to obtain scattering and absorption coefficients, establishes a reliable inversion method for obtaining all parameters in the most general version of the four-flux theory from experimental data.
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| 13. |
- Vargas, William E., et al.
(författare)
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Scattering and absorption cross sections of light diffusing materials retrieved from reflectance and transmittance spectra of collimated radiation
- 2020
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Ingår i: Journal of Modern Optics. - : Taylor & Francis Group. - 0950-0340 .- 1362-3044. ; 67:11, s. 974-991
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Tidskriftsartikel (refereegranskat)abstract
- Four-flux radiative transfer models have been extensively used to describe reflectance and transmittance (R&T) spectra of light scattering and absorbing (S&A) media. Solutions to the differential equations corresponding to the collimated fluxes are obtained by subsequent application of boundary conditions. Explicit expressions for the collimated R&T of light are reported, when considering a light S&A medium contained between two glass slides, an experimental arrangement which is appropriate for liquid suspensions and viscous matrices containing solid particles. A spectral simulated annealing method is applied to retrieve, from measured R&T spectra of collimated light under normal incident radiation, the scattering and absorption coefficients of the composite medium. First, the accuracy of the method is established by applying it to synthetic collimated R&T data. Secondly, we apply the method to experimental data and use it to determine the S&A coefficients of a layer of TiO2 particles dispersed in a PVP/water matrix.
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| 14. |
- Wang, JunXin, et al.
(författare)
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A general phase function of micro/nanoparticle composites.
- 2020
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Ingår i: 2020 Virtual MRS Spring/Fall Meeting.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Light scattering from particles show unique angular scattering patterns, which are strongly dependent on the particle size to incident wavelength ratio and the refractive index contrast between host medium and the particles. Multiple scattering becomes important when the particle concentration increases, which complicates the angular scattering distributions. In many cases, empirical phase functions have to be applied. A novel empirical phase function was introduced to describe the angle-dependent distribution of scattered light from a collection of micro/nanoparticles inside a thin layer. Angular dependence of light scattering from a polymer host containing sub-micron dielectric and metallic particles was measured. The method gives an excellent approximation to the angular effects of multiple scattering arising from aggregation, non-spherical shape and surface roughness. In addition, it is also a good approximation in the single scattering regime, since it closely reproduces scattering phase functions of particles in the Rayleigh, Mie and geometrical optics regimes. The feasibility of our approach was demonstrated by its ability to fit experimental data on the forward and backward scattering profiles of plasmonic and dielectric submicron particle composite layers. The robust and wide applicability of our method is expected to attract a board interest from researchers in physics and materials science.
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| 15. |
- Wang, JunXin, et al.
(författare)
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A novel phase function describing light scattering of layers containing colloidal nanospheres
- 2019
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Ingår i: Nanoscale. - : ROYAL SOC CHEMISTRY. - 2040-3364 .- 2040-3372. ; 11:15, s. 7404-7413
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Tidskriftsartikel (refereegranskat)abstract
- Light scattering from small particles exhibit unique angular scattering distributions, which are strongly dependent on the radius to wavelength ratio as well as the refractive index contrast between the particles and the surrounding medium. As the concentration of the particles increases, multiple scattering becomes important. This complicates the description of the angular scattering patterns, and in many cases one has to resort to empirical phase functions. We have measured the angle dependence of light scattering from a polymer layer containing sub-micron metallic and dielectric particles. The samples exhibited strongly forward and backward peaked scattering patterns, which were fitted to a number of empirical approximative phase functions. We found that a novel two-term Reynolds-McCormick (TTRM) phase function gave the best fit to the experimental data in all cases. The feasibility of the TTRM approach was further validated by good agreement with numerical simulations of Mie single scattering phase functions at various wavelengths and sizes, ranging from the Rayleigh scattering regime to the geometrical optics regime. Hence, the widely adaptable TTRM approach is able to describe angular scattering distributions of different kinds of nanospheres and nanocomposites, both in the single scattering and multiple scattering regimes.
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| 16. |
- Wang, JunXin, et al.
(författare)
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Angle dependent light scattering by gold nanospheres
- 2015
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Ingår i: Inera Conference 2015. - : IOP Publishing.
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Konferensbidrag (refereegranskat)abstract
- Gold nanocrystals exhibit unique optical properties in enhanced light absorption and scattering owing to their extremely large scattering/absorption cross. sections and large electric field enhancements generated by localized surface plasmon resonance. In this work, the optical properties of gold nanospheres with diameters of 60 nm and 200 nm with remarkable uniformity in size were studied both numerically and experimentally. The total transmittance and reflectance as well as the angle. resolved light scattering intensities of the gold nanospheres were measured. The absorption and scattering coefficients were obtained by fitting the experimental data to the two. flux theory and were in qualitative agreement with single. scattering calculations using the Mie theory.
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| 17. |
- Wang, JunXin
(författare)
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Angle dependent light scattering of functional nanoparticle composites
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Varies functional nanoparticles play crucial roles in energy- and optical- related applications. The incorporation of functional nanoparticles into non-absorbing polymers to form optical absorption and scattering thin films have attracted considerable interest due to a successful selection of particles and matrices, synergistic effects of separation and fixation of particles, and controllable layer thicknesses and structures. To investigate the optical parameters, especially absorption and scattering coefficients of the nanocomposites, it is critical to evaluate and optimize those particle based functional layers.In this thesis, we mainly focus on developing approaches for the inversion of scattering and absorption coefficients from optically measured transmittance and reflectance spectra. A two-flux radiative transfer model is robust for this purpose, but its limitation lies in failing to converge the transmittance and reflectance spectra to experimental data owing to the approximation of the completely diffuse scattering patterns. We carried out thorough characterization of angle- and wavelength-resolved light scattering on those nanocomposites with metallic Au, ferromagnetic Fe3O4 and photocatalytic TiO2 nanoparticles. We further developed an empirical scattering phase function, which can fully represent the scattering distributions for aggregated particles in the multiple scattering regime, as well as the single scattering in the Rayleigh, Mie and geometric optical scattering regimes. The incorporation of angle-resolved data into the two-flux theory to derive scattering and absorption coefficients have been validated using the functional nanoparticle composites. Several approximations are also proposed to obtain the scattering and absorption coefficients when angle resolved measurements were not available.The optical performance was investigated on the nanocomposites mentioned above with varied sizes, shapes and concentrations using a spectrophotometer, an in-plane scatterometer and an out-of-plane goniometer. Single particle dark-field scattering spectra were also obtained for Au, Fe3O4, and TiO2 particles in the forward and backward directions.
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| 18. |
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| 19. |
- Wang, JunXin, et al.
(författare)
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Extraction of Backscattering and Absorption Coefficients of Magnetite Nanosphere Composites from Light-Scattering Measurements : Implications for Optomagnetic Sensing
- 2020
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Ingår i: ACS Applied Nano Materials. - : American Chemical Society (ACS). - 2574-0970. ; 3, s. 11172-11183
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Tidskriftsartikel (refereegranskat)abstract
- Interaction of light with magnetic nanoparticles, dispersed insolution or embedded in other materials, is of major interest in a range of applications, one example being optomagnetic sensors. In applied research, light absorption and scattering of nanoparticle composites are often quantified by the Kubelka−Munk two-flux radiative transfer model. In this paper, we synthesized magnetite (Fe3O4) nanospheres with different diameters and encapsulated them into a polymer matrix. Their spectral transmittance and reflectance were investigated by spectrophotometry, together with measurements of angle-resolved scattering in the forward and backward hemispheres. The measured angular distribution was applied to approximate the scattering-phase function inside the film, which could be well described by the revised Reynolds−McCormick model. The backscattering and absorption coefficients were derived by inversion of the Kubelka−Munk relations, using the interface reflectances obtained from angle-dependent measurements. We present detailed optical properties for samples with various particle concentrations and scattering layer thicknesses, consisting of the magnetite and polymer composites. The absorption and backscattering coefficients for particles of diameter 458 nm showed qualitative agreement with single-scattering Mie calculations. The optical properties of composites with smaller particles might beinfluenced by an oxidized Fe2O3-like surface layer. The present approach can be used to study different kinds of magnetic nanoparticle clusters, dispersed in a supporting medium, and thus provide optical parameters of relevance for interpreting results ofoptomagnetic sensing experiments.
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| 20. |
- Wang, JunXin, et al.
(författare)
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Extraction of light absorption and scattering coefficients of gold nanocomposites.
- 2021
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Ingår i: Proceedings Bremen Zoom Workshop on Light Scattering 2021.. - : Leibniz Institute for Materials Engineering IWT. ; , s. 25-28
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Interaction of light with plasmonic Au nanoparticles have received extensive attention owing totheir extremely large absorption and scattering coefficients and enhanced local electromagneticfields. We present a revised Kubelka-Munk two-flux radiative transfer model to determine the absorption and backscattering coefficients of composites containing Au nanospheres from experimental transmittance and reflectance spectra. Using a simple approximation for the forward scattering ratio, the forward scattering coefficients were also obtained. The sum of the simulated absorption coefficient, together with the forward and backward scattering coefficients were comparable with the extinction coefficient derived from measurements of collimated transmittance and reflectance. We also present measurements of single-particle scattering spectra from Au nanospheres immobilized on ITO/glass.
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| 21. |
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| 22. |
- Wang, JunXin, et al.
(författare)
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Light scattering materials for energy-related application: : Determination of absorption and scattering coefficients
- 2019
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Konferensbidrag (refereegranskat)abstract
- Many smart materials with applications in the fields of solar energy and energy-efficient buildings are structured and exhibit significant light scattering. To facilitate optical design of materials and devices for these applications, knowledge of their basic optical parameters, describing light scattering and absorption is necessary. Previous methods to extract these coefficients from experimental data either relied on unverified approximations or required extensive computational effort. In certain cases the obtained scattering and absorption coefficients could even not accurately reproduce the experimental spectra.In this paper we present a novel method for determining scattering (S) and absorption (K) coefficients from total transmittance and reflectance measurements by inversion of the Kubelka-Munk theory. The reflectance parameters appearing in this theory depend on the angular distribution of scattered light inside the material. We present an approximation for this distribution that was verified by comparison with angle resolved scattering measurements. The versatility of our method is demonstrated by a reanalysis of experimental data for several materials of interest in energy-related applications. Specifically we report spectra of S and K for: (a) pigmented polymer foils for radiative cooling applications; (b) suspended particle devices for smart windows; (c) selective solar absorbing paints for solar collectors and (d) solar reflecting TiO2-pigmented paints.
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| 23. |
- Wang, JunXin, et al.
(författare)
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Light scattering materials for energy-related applications : Determination of absorption and scattering coefficients
- 2020
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Ingår i: Materials Today. - : Elsevier BV. - 2214-7853. ; 33:Part 6, s. 2474-2480
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Tidskriftsartikel (refereegranskat)abstract
- To facilitate optical design of energy-efficient materials and devices, a detailed knowledge of their basic optical parameters is necessary. In this paper we present a novel method for determining scattering (S) and absorption (K) coefficients from total transmittance and reflectance measurements by inversion of the Kubelka-Munk theory. The reflectance parameters appearing in this theory depend on the angular distribution of scattered light inside the material. The versatility of our method is demonstrated by a reanalysis of experimental data for several materials of interest in energy-related applications. Specifically, we report spectra of S and K for: (a) pigmented polymer foils for radiative cooling applications; (b) suspended particle devices for smart windows; (c) solar reflecting TiO2-pigmented paints and (d) selective solar absorbing paints for solar collectors.
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| 24. |
- Wang, Yazhou, et al.
(författare)
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n-Type Organic Electrochemical Transistors with High Transconductance and Stability
- 2023
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 35:2, s. 405-415
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Tidskriftsartikel (refereegranskat)abstract
- An n-type conjugated polymer based on diazaisoindigo (AIID) and fluorinated thiophene units is introduced. Combining the strong electron-accepting properties of AIID with backbone fluorination produced gAIID-2FT, leading to organic electrochemical transistors (OECTs) with normalized values of 4.09 F cm-1 V-1 s-1 and a normalized transconductance (gm,norm) of 0.94 S cm-1. The resulting OECTs exhibit exceptional operational stability and long shelf-life in ambient conditions, preserving 100% of the original maximum drain current after over 3 h of continuous operation and 28 days of storage in the air. Our work highlights the advantages of integrating strong electron acceptors with donor fluorination to boost the performance and stability of n-type OECTs.
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| 25. |
- Wu, Hua, et al.
(författare)
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Mixed-Halide Double Perovskite Cs2AgBiX6 (X=Br, I) with Tunable Optical Properties via Anion Exchange
- 2021
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 14:20, s. 4507-4515
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Tidskriftsartikel (refereegranskat)abstract
- Lead-free double perovskites, A2M+M′3+X6, are considered as promising alternatives to lead-halide perovskites, in optoelectronics applications. Although iodide (I) and bromide (Br) mixing is a versatile tool for bandgap tuning in lead perovskites, similar mixed I/Br double perovskite films have not been reported in double perovskites, which may be due to the large activation energy for ion migration. In this work, mixed Br/I double perovskites were realized utilizing an anion exchange method starting from Cs2AgBiBr6 solid thin-films with large grain-size. The optical and structural properties were studied experimentally and theoretically. Importantly, the halide exchange mechanism was investigated. Hydroiodic acid was the key factor to facilitate the halide exchange reaction, through a dissolution–recrystallization process. In addition, the common organic iodide salts could successfully perform halide-exchange while retaining high mixed-halide phase stability and strong light absorption capability.
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