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1
El-Gazzar, Samir M., Rudolph A. Jacob, and Scott P. McGregor. "The Relative and Incremental Valuation Effects of Embedded Value Disclosure by Life Insurers: Evidence from Cross-Listed Firms in the U.S." Accounting Horizons 29, no. 2 (December 1, 2014): 327–39. http://dx.doi.org/10.2308/acch-51015.
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SYNOPSIS European life insurers began disclosing embedded value information (EV) over a decade ago due to concerns with traditional local accounting standards. EV is an estimate of the present value of future net cash flows from in-force life insurance business. However, U.S.-based life insurers have yet to adopt this disclosure, although several surveys and empirical studies suggest that EV disclosure provides valuable information in assessing life insurers' performance. This paper examines the incremental valuation effects of EV disclosure in the presence of U.S. GAAP. We utilize a sample of cross-listed life insurers as surrogates to assess the valuation effects of EV disclosures for U.S. life insurers. Our empirical results show a higher association between EV and stock market prices than those of traditional accounting metrics such as earnings or book value. The results also show that EV has incremental explanatory power beyond those of traditional U.S. GAAP accounting measures. Our findings provide vital input to FASB and IASB as they currently engage in a joint project to develop uniform globally acceptable, comparable accounting standards for life insurers.
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Pandey, Ravindra, Jun Zuo, and A. Barry Kunz. "Derivation of interionic potentials using embedded quantum-mechanical clusters: Cation and anion impurities in MgO." Journal of Materials Research 5, no. 3 (March 1990): 623–28. http://dx.doi.org/10.1557/jmr.1990.0623.
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The ICECAP methodology is used to derive interionic potentials of some cation and anion impurities in MgO, namely, Li+, Na+, K+, Be2+, H−, S2−, and O2−. Analysis is given of the defect energies obtained by using the derived impurity potentials. Based on the available experimental data, comparison is made to justify the reliability of the derived impurity potential for Be2+. The calculated activation energy for Be2+ diffusion comes out to be 1.54 eV as compared to the experimental value of 1.60 eV, which is considered to be very satisfactory.
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Préfontaine, Jacques, Jean Desrochers, and Lise Godbout. "The Informational Content Of Voluntary Embedded Value (EV) Financial Disclosures By Canadian Life Insurance Companies During The Recent Period Of Market Turmoil." International Business & Economics Research Journal (IBER) 10, no. 4 (March 30, 2011): 1. http://dx.doi.org/10.19030/iber.v10i4.4179.
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The informational content and relevance to external stakeholders of voluntary financial disclosures by commercial banks is now becoming more widely recognized. For instance, banks voluntary disclosures of liquidity, interest rate and market risk metrics have been found to be closely associated with market value of equity and credit ratings. So far, there has been very scarce published research on investigating the informational content and relevance to external stakeholders of voluntary financial disclosures by life insurance companies during the recent period of market turmoil. In order to improve upon this situation, this paper updates previous findings and reports on the informational content of voluntary embedded value (EV) financial disclosures by Canadian life insurance companies during the 2000-2010 time period. As opposed to traditional statutory balance sheet and earnings reporting, EV voluntary disclosure attempts to estimate the present value of future earnings generated by a life insurers current book of various insurance businesses. The preliminary results presented in this study indicate that recent EV voluntary financial disclosures failed to communicate intrinsic informational content and to provide value relevance to external stakeholders in the sense that they were not found to be closely associated with life insurers market value of equity and credit ratings during the recent 2007-2010 period of market turmoil.
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Jacob, Rudolph A., Samir El-Gazzar, and Scott McGregor. "Evolution of financial reporting of life insurers." Journal of Financial Regulation and Compliance 25, no. 1 (February 13, 2017): 56–72. http://dx.doi.org/10.1108/jfrc-02-2016-0012.
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Purpose This paper aims to examine the capital market effects and predominance of unregulated embedded value (EV) financial reporting in the life insurance industry in foreign domestic markets, and US markets for foreign firms that cross-list in the USA. Design/methodology/approach Recent empirical archival data are analyzed and evaluated to determine the incremental and relative value relevance of an unregulated valuation metric that is disclosed by life insurers. Findings The findings support the proposition that EV is valuable supplemental information in foreign domestic markets, and in US markets for foreign life insurers that cross-list in the USA. Given that International Accounting Standards Board (IASB) and the Financial Accounting Standards Board (FASB) are engaged in projects to improve accounting standard for insurance companies, and have faced criticism with the existing drafts on this issue, the two institutions ought to consider the valuation relevance of EV disclosures. Moreover, this analysis strongly suggests that financial analysts in the USA should consider EV in valuing life insurers’ stocks. Practical implications The findings discussed in this paper are of special interest to financial reporting policy makers, financial analysts, firm compensation committees and managers, and academics. Originality/value This paper contributes to the extant literature by providing recent evidence that suggests that EV, an unregulated fair value market-driven metric, is more value-relevant than traditional earnings metrics such as earnings and book value. It is the only study that we are cognizant of that critically examines the recent empirical literature on this evolving issue.
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Azmi, N. A., Md Rahim Sahar, and Sib Krishna Ghoshal. "Optical Absorption of Nd3+ Doped Tellurite Glass Containing Ag Nanoparticles." Advanced Materials Research 895 (February 2014): 236–40. http://dx.doi.org/10.4028/www.scientific.net/amr.895.236.
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Understanding the optical properties of rare earth doped tellurite glasses with embedded metallic nanoparticles (NPs) are promising for photonics. Series of Nd3+ doped tellurite glasses containing Ag NPs having chemical composition (70-x)Te2O3-10MgO-20Li2CO3-0.5Nd2O3-xAg, where 0.0 x 1.0 mol% are synthesized. Their optical properties are measured using UV-Vis-NIR spectroscopy. The absorption spectra exhibits nine absorption bands in the wavelength range of 300-900 nm are obtained and the glass showed light emission due to 4F3/2 4I9/2 transition. The values of optical band gap Eopt and Urbach energy Eu are evaluated from the absorption band. The value of Eopt is found to lie between 2.78 and 2.91 eV for the direct transition whereas the Eu values lie between 0.27 and 0.37 eV. The optical behavior of the samples is studied with varying Ag NPs content and the results are compared with similar studies.
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HARBICH, W., Y. BELYAEV, R. KLEIBER, and J. BUTTET. "OPTICAL SPECTROSCOPY OF SIZE-SELECTED SILVER CLUSTERS EMBEDDED IN SOLID NEON: A CLUSTER-SUPPORT INTERACTION STUDY." Surface Review and Letters 03, no. 01 (February 1996): 1147–52. http://dx.doi.org/10.1142/s0218625x96002059.
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Silver ions comprising 8, 11, 20, and 21 atoms have been produced by sputtering, mass-selected in a quadrupole mass filter and deposited at 30-eV landing energy together with neon on a 5-K sapphire support. The absorption spectra show results similar to the system Ag n / argon , but are better resolved. The spectra are compared to gas-phase depletion data and to corresponding sodium clusters. The matrix shift is analyzed and a value of the gas-phase position of the spectra is given.
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Fedrigo, S., W. Harbich, and J. Buttet. "MEDIA EFFECTS ON THE OPTICAL ABSORPTION SPECTRA OF SILVER CLUSTERS EMBEDDED IN RARE GAS MATRICES." International Journal of Modern Physics B 06, no. 23n24 (December 1992): 3767–71. http://dx.doi.org/10.1142/s0217979292001821.
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The optical absorption of small mass selected Agn -clusters (n=7, 11, 15, 21) embedded in solid Ar, Kr and Xe has been measured. The absorption spectra show 1 to 3 major peaks between 3 and 4.5 eV, depending on the cluster size. Changing the matrix gas Ar→Kr→Xe induces a redshift which is comparable for all sizes studied and does not affect the main structure of the absorption spectra. We propose a scheme to estimate the gas phase value of the absorption energies which is in fair agreement with an estimation obtained by a simple model based on a Drude metal.
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Grishakov, Konstantin S., Konstantin P. Katin, and Mikhail M. Maslov. "Theoretical Studies of the Stone-Wales Defect in C36 Fullerene Embedded inside Zigzag Carbon Nanotube." Advances in Physical Chemistry 2016 (November 1, 2016): 1–4. http://dx.doi.org/10.1155/2016/1862959.
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We apply density functional theory at PBE/6-311G(d) level as well as nonorthogonal tight-binding model to study the Stone-Wales transformation in C36 fullerene embedded inside the (14,0) zigzag carbon nanotube. We optimize geometries of two different isomers with the D2d and the D6h symmetries and the transition state dividing them. The mechanism of Stone-Wales transformation from D2d to D6h symmetry for the encapsulated C36 is calculated to be the same as for the isolated one. It is found that the outer carbon wall significantly stabilizes the D6h isomer. However, carbon nanotube reduces the activation barrier of Stone-Wales rearrangement by 0.4 eV compared with the corresponding value for the isolated C36.
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Julg, André, and Odette Julg. "Spherical box model and reduction of Coulomb interactions in the crystal field theory of 3dn ions." Canadian Journal of Chemistry 63, no. 7 (July 1, 1985): 1955–59. http://dx.doi.org/10.1139/v85-323.
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With an accuracy of 0.1 eV, all the electron transitions in any 3d transition element and in the corresponding ions, isolated or inside a crystal, can be obtained with the Hartree–Fock model by using hydrogen d orbitals with suitable effective charges ζ. When the ion is embedded in a crystal, the value of ζ is generally weaker than that in the isolated state. For a given ion, the value of the reduction factor depends on the nature of the crystal. This phenomenon is explained by the boundaries imposed on the ion by the presence of the first neighboring ions (box effect). The application to some crystals (oxides and carbonates) corroborates this interpretation. An empirical relationship between the size of the ion and that of the cavity in which it is confined is proposed.
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Zielony, Eunika, Ewa Płaczek-Popko, and Grzegorz Karczewski. "Dielectric Response of ZnTe–Ti/Al Schottky Junctions with CdTe Quantum Dots Studied by Impedance Spectroscopy." Crystals 10, no. 3 (March 6, 2020): 170. http://dx.doi.org/10.3390/cryst10030170.
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The electrical properties of ZnTe–Ti/Al Schottky junctions were investigated by the impedance spectroscopy (IS) method. Current-voltage (I-V) and capacitance-voltage (C-V) measurements were also performed. The studied samples were the CdTe quantum dot structures embedded in ZnTe matrix and a reference ZnTe sample without quantum dots. C-V characteristics confirmed the presence of quantum dots (QDs) in the structures. Electric modulus and impedance data were analyzed. IS studies proved that long-range conductivity governs the relaxation processes in the junctions. For both samples, the data were fitted with a simple RC circuit composed of a depletion layer capacitance in parallel with bulk resistance and a series resistance of contacts. The activation energy of the relaxation process observed for the reference sample obtained from the Arrhenius plot of the resistance, imaginary impedance, and electric modulus equals 0.4 eV at zero bias. For the quantum dot sample, the value of activation energy determined with the help of the same methods equals 0.2 eV. In conclusion, it was assumed that the relaxation processes for the reference sample are attributed to the trap present in ZnTe host material, whereas those observed for the QD structure are assigned to the deep level associated with defects located close to the QDs created during their growth.
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Ragni, De Luca, Perucca Orfei, Colombini, Viganò, Lugano, Bollati, and de Girolamo. "Insights into Inflammatory Priming of Adipose-Derived Mesenchymal Stem Cells: Validation of Extracellular Vesicles-Embedded miRNA Reference Genes as A Crucial Step for Donor Selection." Cells 8, no. 4 (April 23, 2019): 369. http://dx.doi.org/10.3390/cells8040369.
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Mesenchymal stem cells (MSCs) are promising tools for cell-based therapies due to their homing to injury sites, where they secrete bioactive factors such as cytokines, lipids, and nucleic acids, either free or conveyed within extracellular vesicles (EVs). Depending on the local environment, MSCs’ therapeutic value may be modulated, determining their fate and cell behavior. Inflammatory signals may induce critical changes on both the phenotype and secretory portfolio. Intriguingly, in animal models resembling joint diseases as osteoarthritis (OA), inflammatory priming enhanced the healing capacity of MSC-derived EVs. In this work, we selected miRNA reference genes (RGs) from the literature (let-7a-5p, miR-16-5p, miR-23a-3p, miR-26a-5p, miR-101-3p, miR-103a-3p, miR-221-3p, miR-423-5p, miR-425-5p, U6 snRNA), using EVs isolated from adipose-derived MSCs (ASCs) primed with IFNγ (iASCs). geNorm, NormFinder, BestKeeper, and ΔCt methods identified miR-26a-5p/16-5p as the most stable, while miR-103a-rp/425-5p performed poorly. Our results were validated on miRNAs involved in OA cartilage trophism. Only a proper normalization strategy reliably identified the differences between donors, a critical factor to empower the therapeutic value of future off-the-shelf MSC-EV isolates. In conclusion, the proposed pipeline increases the accuracy of MSC-EVs embedded miRNAs assessment, and help predicting donor variability for precision medicine approaches.
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Mirabella, Salvo, Salvo Cosentino, and Antonio Terrasi. "Synthesis and Light Absorption Mechanism in Si or Ge Nanoclusters for Photovoltaics Applications." Solid State Phenomena 205-206 (October 2013): 465–74. http://dx.doi.org/10.4028/www.scientific.net/ssp.205-206.465.
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Photon absorption in the solar energy range has been investigated in semiconductor nanostructures. Different synthesis techniques (magnetron sputtering, plasma enhanced chemical vapor deposition, ion implantation) followed by thermal annealing, have been employed to fabricate Si or Ge nanoclusters (1-25 nm in size) embedded in SiO2or Si3N4matrices. The thermal evolution in the formation of Si nanoclusters (NCs) in SiO2was shown to depend on the synthesis technique and to significantly affect the light absorption. Experimentally measured values of optical bandgap (EgOPT) in Si NCs evidence the quantum confinement effect which significantly increases the value ofEgOPTin comparison to bulk Si.EgOPTspans over a large range (1.6-2.6 eV) depending on the Si content, on the deposition technique and, in a most significant way, on the structural phase of NC. Amorphous Si NCs have a lowerEgOPTin comparison to crystalline ones. The matrix effect on the synthesis and light absorption in semiconductor NCs was investigated for Ge NCs. Large difference in the Ge NCs synthesis occurred when using SiO2or Si3N4matrices, essentially due to a much lower Ge diffusivity in the latter, which slows down the formation and growth of Ge NCs in comparison to silica matrix. Light absorption in NCs is also shown to be largely affected by the host matrix. Actually, Ge NCs embedded in Si3N4material absorb photons in the solar energy range with a higher efficiency than in silica, due to the different confinement effect. In fact, Si3N4host offers a lower potential barrier to photogenerated carriers in comparison to silica, thus a lower confinement effect is expected, leading to slightly smaller optical bandgap. These effects have been presented and discussed for potential application in light harvesting purposes.
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Kumar, Ranjeet, and D. Saxena. "Fault location in distribution network using travelling waves." International Journal of Energy Sector Management 13, no. 3 (September 2, 2019): 651–69. http://dx.doi.org/10.1108/ijesm-07-2018-0007.
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Purpose An electrical power distribution network is expected to deliver uninterrupted power supply to the customers. The disruption in power supply occurs whenever there is a fault in the system. Therefore, fast fault detection and its precise location are necessary to restore the power supply. Several techniques are proposed in the past for fault location in distribution network but they have limitations as their fault location accuracy depends on system conditions. The purpose of this paper is to present a travelling wave-based fault location method, which is fast, accurate and independent of system conditions. Design/methodology/approach This paper proposes an effective method for fault detection, classification and location using wavelet analysis of travelling waves for a multilateral distribution network embedded with distributed generation (DG) and electric vehicle (EV) charging load. The wavelet energy entropy (WEE) is used for fault detection and classification purpose, and wavelet modulus maxima (WMM) of aerial mode component is used for faulted lateral identification and exact fault location. Findings The proposed method effectively detects and classifies the faults, and accurately determines the exact fault location in a multilateral distribution network. It is also found that the proposed method is robust and its accuracy is not affected by the presence of distributed generation and electric vehicle charging load in the system. Originality/value Travelling wave based method for fault location is implemented for a multilateral distribution network containing distributed generation and electric vehicle load. For the first time, a fault location method is tested in the presence of EV charging load in distribution network.
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Ahmed, Tanvir, Elena V. Levchenko, Alexander V. Evteev, Zi Kui Liu, William Yi Wang, Rafal Abdank-Kozubski, Irina V. Belova, and Graeme E. Murch. "Molecular Dynamics Prediction of the Influence of Composition on Thermotransport in Ni-Al Melts." Diffusion Foundations 12 (September 2017): 93–110. http://dx.doi.org/10.4028/www.scientific.net/df.12.93.
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The influence of composition on thermotransport (coupling between mass and heat transport) in Ni-Al melts is investigated by making use of equilibrium molecular dynamics simulations in conjunction with the Green-Kubo formalism. To describe interatomic interactions in Ni-Al melt models, we employ the embedded-atom method potential developed in [G.P. Purja Pun, Y. Mishin, Phil. Mag., 2009, 89, 3245]. It is demonstrated that the employed interatomic potential gives good agreement with the recent experimental study [E. Sondermann, F. Kargl, A. Meyer, Presented at the 12th International Conference on Diffusion in Solids and Liquids (DSL-2016), 26-30 June 2016, Split, Croatia] regarding the direction of thermotransport in Al-rich liquid Ni-Al alloys. Moreover, the predicted values of the reduced heat of transport (the quantity which explicitly characterizes both the magnitude and direction of thermotransport) in Ni-Al melts, reveal fairly weak composition dependence while being practically independent of temperature at all. Accordingly, in the presence of a temperature gradient, our simulation results for the models of liquid Ni25Al75, Ni50Al50 and Ni75Al25 alloys predict consistently Ni and Al to migrate to the cold and hot ends, respectively. Meanwhile, the highest value, about eV, of the reduced heat of transport is observed for Ni50Al50 alloy model and it slightly decreases towards Al-rich and Ni-rich compositions.
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Gopalakrishnan, K., C. Ramesh, M. Elango, and M. Thamilselvan. "Optical and Magnetic Studies on Cu2O/PANI Nanocomposite Prepared by Chemical Polymerization Method." ISRN Materials Science 2014 (January 21, 2014): 1–7. http://dx.doi.org/10.1155/2014/567927.
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Polyaniline embedded green copper oxide (Cu2O/PANI) nanocomposite has been synthesized through in situ chemical polymerization method in acidic medium at room temperature. The structural, optical, and magnetic properties of Cu2O/PANI nanocomposite were investigated through Fourier transform infrared spectroscopy (FTIR), UV-Vis absorption spectra (UV-Vis spectra), scanning electron microscopy (SEM), photoluminescence spectra (PL), and vibrating sample magnetometer (VSM). FTIR spectra confirmed the formation of Cu2O/PANI composite through the shifting of vibrational peaks of PANI and green Cu2O nanoparticles at 825, 1142, 1299, 1499, 1573 cm−1 and 695 cm−1 respectively. SEM analysis revealed that many aggregations of well-separated irregular shape of Cu2O nanoparticles with diameter about 15–40 nm exist in the composite matrix. Optical absorbance studies further confirmed the formation of composite through the blue shift of absorption peaks of PANI and diminishing intensity peak of Cu2O. Cu2O/PANI nanocomposite demonstrates semiconducting as well as diamagnetic behavior like PANI and Cu2O nanoparticles. The nanocomposite exhibits high relative photoluminescence intensity in blue as well as green-yellow region of visible spectrum. The optical band gap value from absorption coefficient data is found to be 3.23 eV.
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Nomura, Miki, and James B. Adams. "Interstitial diffusion along twist grain boundaries in Cu." Journal of Materials Research 10, no. 11 (November 1995): 2916–24. http://dx.doi.org/10.1557/jmr.1995.2916.
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Interstitial diffusion along twist grain boundaries was studied using the Embedded Atom Method (EAM). Six (100) twist grain boundaries (8.79°–43.6°) in copper were investigated. Interstitial formation energies were found to be much lower (0.26-0.78 eV) than in the bulk, and migration energies were found to be comparable (0.01 eV-0.24 eV) to the bulk values (0.09 eV). The vacancy mechanism is favored for low angle boundaries, and the interstitial mechanism is favored for high angle boundaries. The trends in formation energy versus twist angle were partly explained in terms of the volume expansion of the grain boundary. The total diffusion rate due to both mechanisms was calculated, and agreed reasonably well with experimental data for Cu in polycrystalline Cu. The calculated diffusion rate for specific twist boundaries also agreed well with experimental measurements for Zn/Al.
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Galkin, N. G., D. L. Goroshko, E. A. Chusovitin, A. V. Shevlyagin, K. N. Galkin, and A. K. Gutakovskii. "Silicon p+–p−–n Diodes with Embedded β-FeSi2 and CrSi2 Nanocrystals: Morphology, Crystal Structure and Photoelectric Properties." International Journal of Nanoscience 18, no. 03n04 (April 2, 2019): 1940084. http://dx.doi.org/10.1142/s0219581x19400842.
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The [Formula: see text]–[Formula: see text]–[Formula: see text] diode structures with a variable number of [Formula: see text]-FeSi2 and CrSi2 nanocrystal (NC) bilayer were studied at room and liquid nitrogen temperatures. The high crystal quality of Si and embedded NCs was determined by HRTEM cross-sectional data. This diode demonstrated a photoresponse in the IR region (1.02–0.8[Formula: see text]eV) which was associated with a decrease in recombination losses with the main contribution coming from CrSi2 NCs. Calculations of photoyield and its extrapolation to zero resulted in band gap values of 0.35[Formula: see text]eV at 300[Formula: see text]K and 0.46[Formula: see text]eV at 90[Formula: see text]K. The spectral sensitivity of [Formula: see text][Formula: see text]A/W and specific detectivity of [Formula: see text][Formula: see text](cm Hz[Formula: see text]/W) were determined at [Formula: see text][Formula: see text][Formula: see text]m and T=300[Formula: see text]K.
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TIT, NACIR, and ALTYNBEK MURAT. "STRAIN-INDUCED BAND-MIXING EFFECTS IN ZnS/CdS (001) SUPERLATTICES." International Journal of Modern Physics B 22, no. 12 (May 10, 2008): 1997–2008. http://dx.doi.org/10.1142/s0217979208039290.
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The electronic properties of ZnS/CdS (001) superlattices (SLs) are investigated using the sp3s* tight-binding method versus substrate composition and valence-band offset (VBO). The results show that the electron is always confined within the CdS slabs; and also show a more striking feature due to the prominent localization of the top hole state near the interface region independently from the substrate composition (strain state). Theoretically, we have varied the VBO and inspected its effect on the interface state, and found that this latter persists to exist for VBO values within the interval [-1.4 eV, 0.6 eV]. This interface state is a manifestation of strong band mixing effects induced by the biaxial strain, and is expected to enhance the radiative efficiency of the SLs. The modelling of some available PL data, obtained for thin CdS quantum well embedded inside ZnS , has shown that the samples are of type-I with high energy bandgaps lying within the blue to ultraviolet spectral region.
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Fangsuwannarak, Thipwan, K. Khunchana, and S. T. Rattanachan. "Optical Band Gaps and Electrical Conductance of Si Nanocrystals in SiO2 Matrix for Optoelectronic Applications." Key Engineering Materials 545 (March 2013): 134–40. http://dx.doi.org/10.4028/www.scientific.net/kem.545.134.
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In this study, silicon nanocrystal (Si-nc) films were synthesized by compositing of Si-nc powder embedded in silicon oxide phase. The Si-nc film produced by the spin-coating methode using Tetraethylorthosilicate, ethanol, phosphoric acid, and Si-nc powder as suspension precursors. The variation in structural and optical properties of Si-nc sol films with the amounts of Si-nc powder have been characterized. Atomic force microscopy (AFM) shows that low density level of Si-nc power can result in the amount of porosity in the Si-nc films. It is found that when the Si-nc films have the higher Si-nc density, the small pores in the SiO2 phase were removed. In addition, optical energy gap (Eg) of Si-nc samples was evaluated by the Tauc plot method. It is a crucial attribute for a promising photonic device. The obtained optical bang gap values were extended from 1.10 eV to 1.40 eV as compared with the typical Si bulk. In addition, density of Si-nc clusters has a considerable effect on the electrical conductance of the Si-nc films measured at room temperature.
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Ambrosio, Roberto, Amanda Carrillo, Maria Mota, Karla de la Torre, Richard Torrealba, Mario Moreno, Hector Vazquez, Javier Flores, and Israel Vivaldo. "Polymeric Nanocomposites Membranes with High Permittivity Based on PVA-ZnO Nanoparticles for Potential Applications in Flexible Electronics." Polymers 10, no. 12 (December 11, 2018): 1370. http://dx.doi.org/10.3390/polym10121370.
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This study reports the optical, structural, electrical and dielectric properties of Poly (vinyl alcohol) thin films membranes with embedded ZnO nanoparticles (PVA/ZnO) obtained by the solution casting method at low temperature of deposition. Fourier Transform Infrared spectra showed the characteristics peaks, which correspond to O–H and Zn–O bonds present in the hybrid material. The X-ray diffraction patterns indicated the presence of ZnO structure into the films. The composite material showed low absorbance and a wide band of gap energy from 5.5 to 5.83 eV. The surface morphology for the thin films of PVA/ZnO was studied by Atomic Force Microscopy and Scanning Electron Microscopy. The electrical properties of the membranes were also characterized by current-voltage characteristics and the DC conductivity showed Arrhenius behavior with values of activation energy from 0.62 to 0.78 eV and maximum conductivity at 2.4 × 10−12 S/cm. The dielectric properties of the nanocomposites were measured from low to high frequencies, and the results showed a high dielectric constant (ε) in the order of 104 at low frequency and values from ε ≈ 2000 to 100 in the range of 1 KHz–1 MHz respectively. The properties of PVA/ZnO such as the high permittivity and the low temperature of processing make it a suitable material for potential applications in the development of flexible electronic devices.
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Ragni, Enrico, Carlotta Perucca Orfei, Paola De Luca, Alessandra Colombini, Marco Viganò, Gaia Lugano, Valentina Bollati, and Laura de Girolamo. "Identification of miRNA Reference Genes in Extracellular Vesicles from Adipose Derived Mesenchymal Stem Cells for Studying Osteoarthritis." International Journal of Molecular Sciences 20, no. 5 (March 5, 2019): 1108. http://dx.doi.org/10.3390/ijms20051108.
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Osteoarthritis (OA) leads to chronic pain and disability, and traditional conservative treatments are not effective in the long term. The intra-articular injection of mesenchymal stem cells (MSCs) is considered a novel therapy for OA whose efficacy mainly relies on the adaptive release of paracrine molecules which are either soluble or extracellular vesicles (EVs) embedded. The correct quantification of EV-miRNAs using reliable reference genes (RGs) is a crucial step in optimizing this future therapeutic cell-free approach. The purpose of this study is to rate the stabilities of literature-selected proposed RGs for EV-miRNAs in adipose derived-MSCs (ASCs). EVs were isolated by ultracentrifugation from ASCs cultured with or without inflammatory priming mimicking OA synovial fluid condition. Expression of putative RGs (let-7a-5p, miR-16-5p, miR-23a-3p, miR-26a-5p, miR-101-3p, miR-103a-3p, miR-221-3p, miR-423-5p, miR-425-5p, U6 snRNA) was scored by using the algorithms geNorm, NormFinder, BestKeeper and ΔCt method. miR-16a-5p/miR-23a-3p yielded the most stable RGs, whereas let-7a-5p/miR-425-5p performed poorly. Outcomes were validated by qRT-PCR on miR-146a-5p, reported to be ASC-EVs enriched and involved in OA. Incorrect RG selection affected the evaluation of miR-146a-5p abundance and modulation by inflammation, with both values resulting strongly donor-dependent. Our findings demonstrated that an integrated approach of multiple algorithms is necessary to identify reliable, stable RGs for ASC-EVs miRNAs evaluation. A correct approach would increase the accuracy of embedded molecule assessments aimed to develop therapeutic strategies for the treatment of OA based on EVs.
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San-Fabián, Emilio, Enrique Louis, María Díaz-García, Guillermo Chiappe, and José Vergés. "Transport and Optical Gaps in Amorphous Organic Molecular Materials." Molecules 24, no. 3 (February 9, 2019): 609. http://dx.doi.org/10.3390/molecules24030609.
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The standard procedure to identify the hole- or electron-acceptor character of amorphous organic materials used in OLEDs is to look at the values of a pair of basic parameters, namely, the ionization potential (IP) and the electron affinity (EA). Recently, using published experimental data, the present authors showed that only IP matters, i.e., materials with IP > 5.7 (<5.7) showing electron (hole) acceptor character. Only three materials fail to obey this rule. This work reports ab initio calculations of IP and EA of those materials plus two materials that behave according to that rule, following a route which describes the organic material by means of a single molecule embedded in a polarizable continuum medium (PCM) characterized by a dielectric constant ε . PCM allows to approximately describe the extended character of the system. This “compound” system was treated within density functional theory (DFT) using several combinations of the functional/basis set. In the preset work ε was derived by assuming Koopmans’ theorem to hold. Optimal ε values are in the range 4.4–5.0, close to what is expected for this material family. It was assumed that the optical gap corresponds to the excited state with a large oscillator strength among those with the lowest energies, calculated with time-dependent DFT. Calculated exciton energies were in the range 0.76–1.06 eV, and optical gaps varied from 3.37 up to 4.50 eV. The results are compared with experimental data.
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Membrado, M., and A. F. Pacheco. "Bose–Einstein condensate haloes embedded in dark energy." Astronomy & Astrophysics 611 (March 2018): A81. http://dx.doi.org/10.1051/0004-6361/201731447.
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Context. We have studied clusters of self-gravitating collisionless Newtonian bosons in their ground state and in the presence of the cosmological constant to model dark haloes of dwarf spheroidal (dSph) galaxies. Aims. We aim to analyse the influence of the cosmological constant on the structure of these systems. Observational data of Milky Way dSph galaxies allow us to estimate the boson mass. Methods. We obtained the energy of the ground state of the cluster in the Hartree approximation by solving a variational problem in the particle density. We have also developed and applied the virial theorem. Dark halo models were tested in a sample of 19 galaxies. Galaxy radii, 3D deprojected half-light radii, mass enclosed within them, and luminosity-weighted averages of the square of line-of-sight velocity dispersions are used to estimate the particle mass. Results. Cosmological constant repulsive effects are embedded in one parameter ξ. They are appreciable for ξ > 10−5. Bound structures appear for ξ ≤ ξc = 1.65 × 10−4, what imposes a lower bound for cluster masses as a function of the particle mass. In principle, these systems present tunnelling through a potential barrier; however, after estimating their mean lifes, we realize that their existence is not affected by the age of the Universe. When Milky Way dSph galaxies are used to test the model, we obtain 3.5−1.0+1.3 × 10−22 eV for the particle mass and a lower limit of 5.1−2.8+2.2 × 106 M⊙ for bound haloes. Conclusions. Our estimation for the boson mass is in agreement with other recent results which use different methods. From our particle mass estimation, the treated dSph galaxies would present dark halo masses ~5–11 ×107 M⊙. With these values, they would not be affected by the cosmological constant (ξ < 10−8). However, dark halo masses smaller than 107 M⊙ (ξ > 10−5) would already feel their effects. Our model that includes dark energy allows us to deal with these dark haloes. Assuming quantities averaged in the sample of galaxies, 10−5 < ξ ≤ ξc dark haloes would contain stars up to ~8–15 kpc with luminosities ~9–4 ×103 L⊙. Then, their observation would be complicated. The comparison of our lower bound for dark halo masses with other bounds based on different arguments, leads us to think that the cosmological constant is actually the responsible of limiting the halo mass.
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Akinto, Olakanmi F., and Farida Tahir. "Effective ℒ5 Lagrangian and masses of Majorana neutrinos." International Journal of Geometric Methods in Modern Physics 18, no. 06 (March 3, 2021): 2150081. http://dx.doi.org/10.1142/s021988782150081x.
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Using the fact that neutrinos only participate in weak and gravitational interactions, we explore the possibility of having their masses emerged at the intersection between extended electroweak theory and theory of gravity. We describe how these two seemingly incompatible theories could be embedded in a lepton-number violating 5-dimensional Lagrangian [Formula: see text]. A peculiar feature of this approach is its ability to generate effective Majorana neutrino masses via the spontaneous symmetry breaking (SSB) of Grand Unified Theory (GUT), [Formula: see text] and 4[Formula: see text] symmetric matrix of gravitational couplings. Within the purview of this theoretical framework, we obtain values for the effective Majorana mass [Formula: see text][Formula: see text]meV, and the Majorana neutrino masses [Formula: see text][Formula: see text]meV, [Formula: see text][Formula: see text]meV, [Formula: see text][Formula: see text]meV, [Formula: see text][Formula: see text]meV and [Formula: see text][Formula: see text]eV. Our results are in good agreement with both experimental and cosmological data.
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Grandjean, Thomas, Jakobus Groenewald, Andrew McGordon, Widanalage Widanage, and James Marco. "Accelerated Internal Resistance Measurements of Lithium-Ion Cells to Support Future End-of-Life Strategies for Electric Vehicles." Batteries 4, no. 4 (October 4, 2018): 49. http://dx.doi.org/10.3390/batteries4040049.
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Industrial and academic communities have embarked on investigating the sustainability of vehicles that contain embedded electrochemical energy storage systems. Circular economy strategies for electric vehicle (EV) or hybrid electric vehicle (HEV) battery systems are underpinned by implicit assumptions about the state of health (SOH) of the battery. The internal resistance of battery systems is the essential property for determining available power, energy efficiency, and heat generation. Consequently, precise measurement is crucial to estimate the SOH; however, the international standards and best practice guides that exist to define the measurements include long preconditioning and rest times that make the test duration prohibitive. The aim of this research is to critically evaluate whether test duration times for internal resistance measurements can be reduced to values that may facilitate further end-of-life (EOL) options. Results reveal a newly developed technique using pulse-multisines is two to four times faster to perform when compared to the standard protocol whilst maintaining accuracy for battery electric vehicle (BEV) and HEV cells, respectively. This novel method allows different stakeholders to rank the relative importance of test accuracy verses experimental test time when categorising used Li-ion cells for different EOL applications.
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González Sánchez, E., J. Gómez-Román, A. Muñoz-Callejas, A. Marengo, N. Tsapis, K. Bohne-Japiassu, M. Á. González-Gay, et al. "POS0331 LUNG TARGETED DELIVERY OF EVEROLIMUS AS A NEW TREATMENT OF SCLERODERMA-RELATED INTERSTITIAL LUNG DISEASE (SSc-ILD) DEVELOPED BY PSGL-1 KO MICE." Annals of the Rheumatic Diseases 80, Suppl 1 (May 19, 2021): 393.1–393. http://dx.doi.org/10.1136/annrheumdis-2021-eular.2498.
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Background:Interstitial lung disease (ILD), the main cause of mortality in scleroderma (SSc) patients (1), has no treatment (2). P-selectin glycoprotein ligand 1 (PSGL-1), the main ligand for P-Selectin, is expressed on leukocytes and responsible for the initial steps of extravasation (3). The absence of PSGL-1 in mice spontaneously develops an autoimmune syndrome similar to human SSc with fibrosis, vascular damage, autoantibodies and pulmonary arterial hypertension in females, and almost 60% of animals older than 12 months develop ILD with aging (4). In this work, the therapeutic action of everolimus-loaded nanomedicine given by local administration as a treatment for ILD was evaluated. The intratracheal administration of everolimus loaded into in liposomes decorated with hyaluronic acid (HA) is studied as an administration strategy to reach the inflammatory and fibrotic cells, targeting these cells and avoiding systemic effects and possible toxicity on epithelial cellsObjectives:1) To study the effect of everolimus on bronchoalveolar lavage (BAL) cell populations and in lung pathology in SSc-ILD PSGL-1 KO mice2) To analyze the intratracheal application of everolimus included in empty liposomes (Lip+Ev) vs. liposomes decorated with hyaluronic acid (Lip-HA+Ev) as an administration strategy to decrease drug toxicity and increase drug effectivityMethods:In an observational study, PSGL-1−/− C57BL/6 males older than 12 months (n=4) were treated intratracheally with 4 doses of Lip or Lip-HA (with or without everolimus included), once a week (Lip+Ev 295.67µg/mL; Lip+Ev 82.73µg/mL; Lip-HA+Ev 82.73µg/mL). Then, animals were euthanatized and BAL and lungs were obtained. BAL cells were stained for flow cytometry analysis. Lungs were embedded in paraffin blocks for blind histological analysis by a pathologist and evaluated for interstitial inflammation and fibrosis degree. Lip-HA was selected as the treatment of choice for a second experiment (n=8) following the same experimental design (86.22µg/mL)Results:The observational study showed an increase in CD45+, alveolar macrophages (AM), eosinophils (Eos), granulocytes (Gr1+) and T cells in the BAL of untreated PSGL-1-/- mice compared with WT mice. Everolimus reduced these populations to WT levels in all casesLip-HA+Ev administration was chosen for further experiments because a lower dose of the drug gave a better result than the high dose in undecorated liposomes. Reduction of CD45+, AM, eosinophils, and CD45- cells populations by Lip-HA+Ev was confirmed. Lip-HA treatment increased the number of neutrophils and T cells, but this effect is controlled by the everolimus administrationHistological lung analysis showed an increase in interstitial inflammation and fibrosis in untreated PSGL-1-/- and empty Lip-HA experimental groups. Treatment with everolimus included in Lip-HA reduced the fibrotic and inflammatory interstitial lung lesions, reaching values similar to those observed in WT miceConclusion:PSGL-1 KO mice present ILD associated with scleroderma (SSc-ILD) with an increase of CD45+, Gr1+, Eos, T cells and AM populations in the BAL. Intratracheal treatment with everolimus included in liposomes decorated with hyaluronic acid reduces immune cell infiltration and fibrosis once SSc-ILD is establishedReferences:[1]Solomon JJ, Olson AL, Fischer A, Bull T, Brown KK, Raghu G (2013). Scleroderma lung disease[2]Singh D, Parihar AK, Patel S, Srivastava S, Diwan P, Singh MR (2019). Scleroderma: An insight into causes, pathogenesis and treatment strategies. Pathophysiology, 26(2)[3]Zarbock A, McEver RP, Hidalgo A (2011). Leukocyte Ligands for Endothelial Selectins: Specialized Glycoconjugates That Mediate Rolling and Signaling Under Flow. BLOOD[4]Pérez-Frías A, Núñez-Andrade N, et al. (2014). Development of an autoimmune syndrome affecting the skin and internal organs in P-selectin glycoprotein ligand 1 leukocyte receptor-deficient mice. Arthritis RheumatolDisclosure of Interests:None declared
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Hernandez-Hernandez, Arturo, Victor Tapio Rangel-Kuoppa, Thomas Plach, Francisco De Moure-Flores, Jose G. Quiñones-Galvan, Karen E. Nieto Zepeda, Martin Zapata-Torres, and Miguel Meléndez-Lira. "Synthesis of Light Emitting Ge Nanocrystals by Reactive RF Sputtering." Solid State Phenomena 178-179 (August 2011): 61–66. http://dx.doi.org/10.4028/www.scientific.net/ssp.178-179.61.
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In this work we report the results of the synthesis, structural and optical characterization of SiO2/Ge/SiO2heterostructures by reactive RF sputtering. The SiO2films were grown by reactive sputtering employing a plasma mixture of oxygen and argon. The Ge layer was grown employing an Ar atmosphere. The samples were prepared on p-type Si (1 1 1) substrates by reactive sputtering. The effect of the partial pressure of oxygen on the electronic properties of the heterostructure is reported[1]. Structural characterization was carried out by grazing angle X-ray difraction. Surface roughness was quantified by atomic force microscopy. The presence of Ge nanocrystals (Ge-NCs) was evidenced by X-ray diffraction. The vibrational properties were studied by Raman spectroscopy. The Raman spectra showed modes associated to germanium indicating the formation of low dimensionality germanium particles embedded within a SiO2matrix. Photoluminescence emission is observed around ~1.7 eV and it is associated to the quantum confinement of carriers in Ge-NCs. Ohmic contacts were deposited using a van der Pauw geometry employing an a AuSb alloy for the contacts. Temperature dependent Hall (T-Hall) measurements were done between 35 K and 150 K, using the van der Pauw method. The results indicated low resistivity values that could be explained due to some variable range hopping conduction mechanism.
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Gehlot, Anita, Sultan S. Alshamrani, Rajesh Singh, Mamoon Rashid, Shaik Vaseem Akram, Ahmed Saeed AlGhamdi, and Fahad R. Albogamy. "Internet of Things and Long-Range-Based Smart Lampposts for Illuminating Smart Cities." Sustainability 13, no. 11 (June 4, 2021): 6398. http://dx.doi.org/10.3390/su13116398.
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Intelligent and resilient infrastructure is necessary for smart cities for contributing flexible and smart amenities to the citizens. Concerning the United Nations (UN) estimation, the global population residing in urban cities will reach 68% by 2050. Additionally, the Sustainable Energy Action Plans (SEAP) report suggests implementing energy efficiency technologies in smart cities to meet the rising urban population requirement. Internet of Things (IoT) technology empowers to achieve the goal of energy efficiency by integrating sensors, wireless technology, and renewable energy sources in the lighting system. At present, the IoT-based lighting system in urban cities is implemented with streetlamps and lampposts. In this study, we are focusing on lampposts, as it has the flexibility of establishing and implementing a multitude of applications on a single system. Due to technological advancement, the lamppost is embedded with multiple sensors, communication protocols, and energy distribution infrastructure for delivering smart and affordable amenities to the citizens residing in the smart cities. This motivates us to implement a smart lamppost that provides a multitude of applications such as smart light, digital signs, environmental monitoring conditions, electric vehicle (EV) charging port, wireless fidelity (Wi-Fi) hotspot, etc., on a single lamppost. This study proposed the IoT-assisted fog and edge-based smart lamppost for the smart cities to realize the smart infrastructure. Further, this smart lamppost is integrated with low power and long-range communication, i.e., Long Range (LoRa), enabling the smart lamppost to communicate the sensory data to a long-range. Additionally, LoRa is integrated with a Wi-Fi module for establishing the interconnection between the smart lamppost and IoT server. Generally, the proposed architecture is broad perspective; however, we have developed and implemented the hardware models of three components including lighting system, environmental parameters and image sensing in real time. Lighting system and environmental parameter monitoring are integrated on same hardware model for sensing and logging the real-time values of temperature, humidity, CO and light intensity on the IoT server. The developed image sensing prototype based on ESP 32 controller is also evaluated in real-time scenarios, and the performance of the prototype is efficient. The proposed system delivers reliable performance in terms of sensing and communicating environmental parameters and images to the IoT server. Moreover, in future, we will complete the development of other components of the smart lamppost for enhancing the smarter infrastructure in smart cities.
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Eden, Yoram. "The Implementation of Embedded Value (EV) Reporting in Israel: Myth and Reality." Asia-Pacific Journal of Risk and Insurance 8, no. 1 (January 10, 2013). http://dx.doi.org/10.1515/apjri-2012-0010.
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Préfontaine, Jacques, Jean Desrochers, and Lise Godbout. "The Informational Content Of Voluntary Embedded Value (EV) Financial Disclosures By Canadian Life Insurance Companies." International Business & Economics Research Journal (IBER) 8, no. 12 (February 15, 2011). http://dx.doi.org/10.19030/iber.v8i12.3192.
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The informational content and relevance to external stakeholders of voluntary financial disclosures by commercial banks is now becoming more widely recognized. For instance, banks voluntary disclosures of liquidity, interest rate and market risk metrics have been bound to be closely associated with market value of equity and credit ratings. So far, there has been very scarce published research on investigating the informational content and relevance to external stakeholders of voluntary financial disclosures by life insurance companies. In order to improve upon this situation, this paper studies and reports the informational content of voluntary embedded value (EV) financial disclosures by Canadian life insurance companies. As opposed to traditional statutory balance sheet and earnings reporting, EV voluntary disclosure attempts to estimate the present value of future earnings generated by a life insurers current book of various insurance businesses. The preliminary results presented in this study indicate that EV voluntary financial disclosures communicate intrinsic informational content and provide value relevance to external stakeholders in the sense that they were found to be closely associated with life insurers market value of equity.
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Taylor, V. A., I. Moseley, S. Sun, R. Smith, A. Roy, V. U. Ludwig, and J. A. Brewer. "Awareness drives changes in reward value which predict eating behavior change: Probing reinforcement learning using experience sampling from mobile mindfulness training for maladaptive eating." Journal of Behavioral Addictions, July 15, 2021. http://dx.doi.org/10.1556/2006.2021.00020.
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AbstractBackground and aimsMaladaptive eating habits are a major cause of obesity and weight-related illness. The development of empirically-based approaches, such as mindfulness training (MT) that target accurate mechanisms of action to address these behaviors is therefore critical. Two studies were conducted to examine the impact of MT on maladaptive eating and determine the involvement of reinforcement learning mechanisms underlying these effects.MethodsIn Study1, maladaptive eating behaviors were assessed using self-report questionnaires at baseline and 8 weeks after an app-based MT intervention (n = 46). A novel mindful eating craving tool was embedded in our intervention to assess: eating behaviors (intake frequency/magnitude), and reward (contentment ratings) experienced after eating. Using a well-established reinforcement learning (Rescorla-Wagner) model, expected reward values (EV) were estimated as a function of contentment levels reported after eating. In Study2 (n = 1,119), craving tool assessments were examined in an independent sample using the app in a real-world naturalistic context.ResultsStudy 1's results revealed a significant decrease in EV and eating behaviors across craving tool uses. In addition, changes in reward values predicted decreases in eating behaviors. Finally, Study 1's results revealed significant pre-post intervention reductions in self-reported eating behaviors. In Study2, we observed a significant decrease in EV, but not in eating behaviors, across craving tool uses. Study 2 also revealed a predictive relationship between EV and eating behaviors.Discussion and conclusionsThese results support the implementation of MT to prevent and treat maladaptive eating behaviors, which target reinforcement learning processes as mechanisms of action.
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Nguyen, Bella, Nicholas C. Wong, Tim Semple, Michael Clark, Stephen Q. Wong, Connull Leslie, Bob Mirzai, Michael Millward, Katie Meehan, and Annette M. Lim. "Low-coverage whole-genome sequencing of extracellular vesicle-associated DNA in patients with metastatic cancer." Scientific Reports 11, no. 1 (February 17, 2021). http://dx.doi.org/10.1038/s41598-021-83436-1.
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AbstractLow-coverage whole-genome sequencing (LC-WGS) can provide insight into oncogenic molecular changes. Serum extracellular vesicles (EV) represent a novel liquid biopsy source of tumoral DNA. This study compared copy number alteration (CNA) profiles generated from LC-WGS of formalin-fixed paraffin-embedded (FFPE) tumoral DNA and EV-DNA obtained from cancer patients. Patients with squamous cell carcinoma of the base of tongue (n = 3) and cutaneous squamous cell carcinoma (n = 2) were included. LC-WGS (0.5-1X coverage) was performed on FFPE-DNA and serum EV-DNA. Similarity between CNA profiles was analysed using QDNAseq. FFPE samples had a mean CNA of 31 (range 17–50) over 1.9 × 109 (range 1.0–2.6 × 109) bp in length, and EV samples had a mean CNA value of 17 (range 7–19) over 7.6 × 108 (range 2.9–15 × 108) bp in length. A mean of 8 (range 0–21) CNA over 5.9 × 108 (range 1.6–14 × 108) bp in length was found to overlap between EV and FFPE-derived samples per patient. Although the mean correlation efficient between samples was r = 0.34 (range − .08 to 0.99), this was not statistically significant (p > 0.05). Regions of highest deletion and duplication in FFPE samples were not well reflected in the EV-DNA. Selected CNA regions in EV-associated DNA were reflective of the primary tumor, however appreciation of global CNA and areas of most significant change was lost. The utility of LC-WGS of EV-derived DNA is likely limited to molecular alterations of known interest.
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Hassan, K. M., A. K. Sharma, J. Narayan, J. F. Muth, and C. W. Teng. "Germanium Nanostructures Fabricated by PLD." MRS Proceedings 536 (1998). http://dx.doi.org/10.1557/proc-536-329.
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AbstractQuantum confined nanostructures of semiconductors such as Ge and Si are being actively studied due to their interesting optical and electronic transport properties. We fabricated Ge nanostructures buried in the matrix of polycrystalline-AIN grown on Si(111) by pulsed laser deposition at lower substrate temperatures than that used in previous studies. The characterization of these structures was performed using high resolution transmission electron microscopy (HRTEM), photoluminescence and Raman spectroscopy. HRTEM observations show that the Ge islands are single crystal with a pyramidal shape. The average size of Ge islands was determined to be 15 nm, considerably smaller than that produced by other techniques. The Raman spectrum reveals a peak downward shift, upto 295 cm−1, of the Ge-Ge mode caused by quantum confinement in the Ge-dots. Photoluminescence (PL) was observed both with a single layer of Ge nanodots embedded in the AlN matrix and from ten layers of dots interspersed with AIN. The PL of the dots was blue shifted by ˜0.266 eV from the bulk Ge value of 0.73 eV at 77 K, resulting in a distinct peak at ˜1.0 eV. The full width at half maximum (FWHM) of the peak was 13 meV, for the single layer and 8 meV for the ten layered sample, indicating that the Ge nanodots are fairly uniform in size, which was found to be consistent with our HRTEM results. The importance of pulsed laser deposition (PLD) in fabricating novel nanostructures is discussed.
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López, M., B. Garrido, O. González, C. García, A. Pérez-Rodríguez, J. R. Morante, C. Bonafos, M. Carrada, R. J. Rodríguez, and J. Montserrat. "Correlation between Structural and Optical Properties of Si Nanocrystals in SiO2: Model for the Visible Light Emission." MRS Proceedings 647 (2000). http://dx.doi.org/10.1557/proc-647-o13.5/r8.5.
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AbstractThe correlation between the structural and optical properties of Si nanocrystals embedded in SiO2 is the key factor to understand their emission mechanism. However, there is a great difficulty in imaging Si nanocrystals in SiO2 and measuring their size distribution because of the lack of contrast in electron microscopy. We have used here a new method for imaging Si nanocrystals by using high resolution electron microscopy in conjunction with conventional electron microscopy in dark field conditions. Regarding the optical properties, the band-gap energies and photoluminescence have been measured by direct and independent methods. The results have allowed experimental determination, for the first time in this material, of the experimental Stokes shift between absorption and emission as a function of crystallite size. The experimental band-gap versus size correlates well with the most accurate theoretical predictions. Moreover, the photoluminescence energy emission versus crystallite size shows a parallel behaviour to that of band-gap energy. Consequently, the experimental Stokes shift is independent of nanocrystal size and is found to be 0.26±0.03 eV. This value is almost twice the energy of the Si-O vibration (0.134 eV). These results suggest that the dominant emission of Si nanocrystals passivated with SiO2 is a fundamental transition spatially located at the Si-SiO2 interface and with the assistance of a local Si-O vibration.
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López, M., B. Garrido, O. González, C. García, A. Pérez-Rodríguez, J. R. Morante, C. Bonafos, M. Carrada, R. J. Rodríguez, and J. Montserrat. "Correlation between Structural and Optical Properties of Si Nanocrystals in SiO2: Model for the Visible Light Emission." MRS Proceedings 650 (2000). http://dx.doi.org/10.1557/proc-650-r8.5/o13.5.
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ABSTRACTThe correlation between the structural and optical properties of Si nanocrystals embedded in SiO2 is the key factor to understand their emission mechanism. However, there is a great difficulty in imaging Si nanocrystals in SiO2 and measuring their size distribution because of the lack of contrast in electron microscopy. We have used here a new method for imaging Si nanocrystals by using high resolution electron microscopy in conjunction with conventional electron microscopy in dark field conditions. Regarding the optical properties, the band-gap energies and photoluminescence have been measured by direct and independent methods. The results have allowed experimental determination, for the first time in this material, of the experimental Stokes shift between absorption and emission as a function of crystallite size. The experimental band-gap versus size correlates well with the most accurate theoretical predictions. Moreover, the photoluminescence energy emission versus crystallite size shows a parallel behaviour to that of band-gap energy. Consequently, the experimental Stokes shift is independent of nanocrystal size and is found to be 0.26±0.03 eV. This value is almost twice the energy of the Si-O vibration (0.134 eV). These results suggest that the dominant emission of Si nanocrystals passivated with SiO2 is a fundamental transition spatially located at the Si-SiO2 interface and with the assistance of a local Si-O vibration.
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Oh, YoungHwan, WooSik Nam, GonSub Lee, JeaGun Park, and YongBok Lee. "Small Molecular Organic Nonvolatile Memory Fabricated with Ni Nanocrystals Embedded in Alq3." MRS Proceedings 1071 (2008). http://dx.doi.org/10.1557/proc-1071-f05-12.
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AbstractRecently, organic nonvolatile memory has attracted much interest as a candidate device for next generation nonvolatile memory because of its simple process, small device area, and high speed. To investigate electrical characteristics of small molecular organic nonvolatile memory with Ni as a middle metal layer, we developed a small molecular organic nonvolatile memory with the device structure of Aluminum tris (8-hydroxyquinolate) (Al/Alq3), Ni nanocrystals, and Alq3/Al. A high vacuum thermal deposition method was used for the device fabrication. It is critical that the fabrication process condition for Ni nanocrystals be optimized, including ∼100 Å thickness, 0.1 Å/sec-evaporation rate, and in-situ plasma oxidation for effective oxidation. The reasons we chose Ni for the middle metal layer are that Ni has a smaller grain boundary, which is beneficial for scaling down and has a larger work function (∼5.15 eV) that can make a deep quantum well in an energy band diagram, compared with that of Al. Our device showed an electrical nonvolatile memory behavior including Vth of ∼2 V, Vw (write) of ∼3.5 V, negative differential region (NDR) of 3.5∼7 V, Ve (erase) of 8 V, and symmetrical electrical behavior at reverse bias. In addition, an interesting behavior of electrical properties was that, although retention and endurance characteristics were similar to the Al device, the Ion/Ioff ratio was greater than 104 at Vr (read) of 1 V. This value of the Ni device was higher than 102 compared to that of the Al device. Also, small molecular organic nonvolatile memory with a Ni middle layer with α-NPD at same fabrication condition showed more unstable characteristics than Alq3. We can speculate that there is a relationship in fabrication condition between the middle metal material and the organic material. Finally, we conclude that our device with a Ni nanocrystals middle layer is more reliable and useful for small molecular organic nonvolatile memory.
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Tibbits, P., M. Karimi, D. Ila, I. Dalins, and G. Vidali. "Order/Disorder and Phase Diagram of H on Pd(100)." MRS Proceedings 193 (1990). http://dx.doi.org/10.1557/proc-193-289.
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ABSTRACTAn atomistic simulation of H-Pd(100) provided a phase diagram for the c2×2 H overlayer phase. The Embedded Atom Method (EAM) calculated energy of each configuration of atoms and the Metropolis Monte Carlo algorithm equilibrated the structure and generated configurations from which to sample the structure factor for the H overlayer. The procedure provided the expectation of the square of the structure factor modulus, < |S2| >, as a function of temperature at three coverages. The inflection point of the < |S2| > versus T curve estimated the critical temperature for disordering, Tc,, for one value of coverage, θ. The plot of Tc versus θ, the phase boundary for the c2×2 phase, lay about 125 K below the experimentally determined boundary. A comparison of the energies of ordered and disordered phases showed ΔE = 0.016 eV per hydrogen atom. Equating this unrealistically small energy difference to thermal kinetic energy (3/2)kBTc at the critical temperature implies Tc ≈ 100 K. Obtaining – |S2| > values relatively free of noise at such low temperatures required large numbers of Monte Carlo steps. The c2×2 phase is the experimentally determined stable low temperature phase, and was assumed to be the lowest-energy phase possible in this simulation. The very small ΔE indicates that some other ordered phase may be more stable than c2×2 in the EAM model.
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Wu, Xiaojing, Jérôme Hénin, Laura Baciou, Marc Baaden, Fabien Cailliez, and Aurélien de la Lande. "Mechanistic Insights on Heme-to-Heme Transmembrane Electron Transfer Within NADPH Oxydases From Atomistic Simulations." Frontiers in Chemistry 9 (May 4, 2021). http://dx.doi.org/10.3389/fchem.2021.650651.
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NOX5 is a member of the NADPH oxidase family which is dedicated to the production of reactive oxygen species. The molecular mechanisms governing transmembrane electron transfer (ET) that permits to shuttle electrons over the biological membrane have remained elusive for a long time. Using computer simulations, we report conformational dynamics of NOX5 embedded within a realistic membrane environment. We assess the stability of the protein within the membrane and monitor the existence of cavities that could accommodate dioxygen molecules. We investigate the heme-to-heme electron transfer. We find a reaction free energy of a few tenths of eV (ca. −0.3 eV) and a reorganization free energy of around 1.1 eV (0.8 eV after including electrostatic induction corrections). The former indicates thermodynamically favorable ET, while the latter falls in the expected values for transmembrane inter-heme ET. We estimate the electronic coupling to fall in the range of the μeV. We identify electron tunneling pathways showing that not only the W378 residue is playing a central role, but also F348. Finally, we reveal the existence of two connected O2−binding pockets near the outer heme with fast exchange between the two sites on the nanosecond timescale. We show that when the terminal heme is reduced, O2 binds closer to it, affording a more efficient tunneling pathway than when the terminal heme is oxidized, thereby providing an efficient mechanism to catalyze superoxide production in the final step. Overall, our study reveals some key molecular mechanisms permitting reactive oxygen species production by NOX5 and paves the road for further investigation of ET processes in the wide family of NADPH oxidases by computer simulations.
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Abdul Karim, Kasrul, Md Nazri Othman, Auzani Jidin, Abdul Rahim Abdullah, and Mohd Zulkifli Ramli. "Development of Integrated Monitoring System for Re-Electric Vehicle." Jurnal Teknologi 71, no. 2 (November 27, 2014). http://dx.doi.org/10.11113/jt.v71.3727.
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Awareness of technological development of an electric vehicle (EV) has increased from year to year, particularly with commercialization of the electric vehicles in the consumer market. In contrast to the internal combustion engine (ICE) vehicles based on gasoline, electric vehicles rely on the batteries as the sole energy source. Although the electric vehicles have a relatively simple structure and their operations are more environmentally friendly, the battery energy capacity is limited, high in price and requires long charging time which as a result will limit the driving distance. Therefore, to tackle these issues a dedicated monitoring system for the battery is designed and developed. The developed integrated monitoring system consists of graphical display, measuring circuitries, speedometer, GPS, gyro and the controller module that monitors the batteries' status as well as other parameters that are important for the safe operation of electric vehicles. In addition the data was recorded during the driving for research purpose and future references, and the safety aspects are embedded in the controller module. The development of the system and its algorithm is described in this paper. The integrated monitoring system was tested in a real driving conditions to verify the functionality. The results show that the system is capable to measure and record all key parameter values, especially related to individual batteries along the journey. It also provides the user with a high degree of reliability through interactive and informative graphical display. As a conclusion, the use of the integrated monitoring system is not only able to ensure the efficient use of the battery and prolong its life span but also the safety aspect is considered in the design. For further system improvement, the battery characteristic, regenerative braking and traffic conditionswas incorporated into the algorithm.