Relevant bibliographies by topics / D-band Theory

Academic literature on the topic 'D-band Theory'

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Published: 6 September 2023

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Journal articles on the topic "D-band Theory"

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Natori, A., and H. Kamimura. "Theory of a D- Band." Progress of Theoretical Physics Supplement 69 (May 14, 2013): 353–64. http://dx.doi.org/10.1143/ptp.69.353.

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Moriarty, John A. "Generalized pseudopotential theory of d-band metals." International Journal of Quantum Chemistry 24, S17 (July 9, 2009): 541–54. http://dx.doi.org/10.1002/qua.560240859.

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Jiao, Jun Rong, Jia Heng Wang, Chang Wei Gong, Yue Sheng Chai, and Wei Shao. "Structural, Optical and Magnetic Properties of W-Doped TiO2." Applied Mechanics and Materials 556-562 (May 2014): 330–34. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.330.

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Based on the density functional theory method, the ab initio calculation with GGA+U was performed to investigate the electronic structure and properties of W-doped TiO2. The results indicated that W-doping induced ferromagnetism and shifted the absorption spectra to visible light region. The ferromagnetism derived from the spin-split of O 2p and W 5d caused by p–d orbit hybridization. Several impurity bands under the conduction band decreased the band gap.
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Fujisawa, Jun-ichi. "Highly-selective absorption control in photosynthetic chlorin dyes." Journal of Porphyrins and Phthalocyanines 19, no. 04 (April 2015): 601–9. http://dx.doi.org/10.1142/s1088424614501041.

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Selective chemical control of light-absorption bands of dye molecules in which the wavelengths of two or more absorption bands are individually controlled by chemical modifications is an ultimate challenge in chemistry and an important subject for their wide applications. Recently, selective absorption tuning was first reported in photosynthetic bacteriochlorin dyes. In the bacteriochlorin dyes, either the visible or near IR band is selectively shifted by the chemical modifications almost retaining the other band. Fujisawa et al. clarified that the selective absorption tuning is accomplished by chemical control of configuration interactions in the two two-level systems. This paper reports on more highly-selective absorption tuning in photosynthetic chlorin dyes, bacteriochlorophylls (BChls) d and e and the mechanism. In BChls d and e, the near UV band (so-called Soret band) is selectively red-shifted by the chemical modifications of BChl d involving the formylation and methylation perfectly retaining the visible band (so-called Qy). Density functional theory (DFT) and time-dependent DFT analyses showed that the red-shift of the Soret band is predominantly attributed to the large stabilization of the second lowest unoccupied molecular orbital induced by the formylation. In contrast, the Qy absorption retention results from the perfect cancellation between the positive excitation-energy change due to the formylation and negative excitation-energy change due to the methylation, both of which are significantly contributed by configuration interactions. This work reveals that the highly-selective absorption control in BChls d and e is accomplished by the complicated control of configuration interactions in the four-level system.
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Pan, Hongbo, Jia Tian, Taoyang Wang, Jing Wang, Chengbao Liu, and Lei Yang. "Band-to-Band Registration of FY-1C/D Visible-IR Scanning Radiometer High-Resolution Picture Transmission Data." Remote Sensing 14, no. 2 (January 17, 2022): 411. http://dx.doi.org/10.3390/rs14020411.

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The visible-IR scanning radiometer (VIRR) of FY1-C/D meteorological satellites consists of 10 bands with 4 different focal plane assemblies (FPAs). However, there are significant band-to-band registration (BBR) errors between different bands, which cannot be compensated for by a simple shift in the along-scan direction. A rigorous BBR frame was proposed to analyze the sources of misregistration in the whisk-broom camera. According to theory, the 45° scanning mirror introduces tangent function style misregistration in the along-track direction and secant function style misregistration in the across-track direction between different bands if the bands are not in the same optical axis. As proven by the experiments of both FY-1C and FY-1D, the image rotation caused by the 45° scanning mirrors plays a major role in the misregistration. However, misregistration between different FPAs does not strictly adhere to this theory. Therefore, a polynomial-based co-registration method was proposed to model the BBR errors for the VIRR. To achieve 0.1 pixel accuracy, a fourth-degree polynomial was used for BBR in the along-scan direction, and a fifth-degree polynomial was used for the along-track direction. For the reflective bands, the root-mean-square errors (RMSEs) of misregistration could be improved from 3 pixels to 0.11 pixels. Limited by matching accuracy, the RMSEs of misregistration between thermal bands and reflective bands were approximately 0.2 to 0.4 pixels, depending on the signal-to-noise ratio.
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Silva-Molina, R. A., R. Gámez-Corrales, J. M. Hernández-Cazares, and I. G. Espinoza-Maldonado. "Study of Optical Vibrations Modes of Mineral Graphite by Micro Raman Spectroscopy." MRS Proceedings 1481 (2012): 37–43. http://dx.doi.org/10.1557/opl.2012.1630.

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ABSTRACTWe present experimental and theoretical Raman spectra of natural graphite mineral of Sonora, Mexico. In this work, we take the advantage of the utility of the RAMAN spectroscopy as a technique to determine the crystallinity and structure of graphite mineral. The RAMAN spectroscopy provides information that can be used to determine the degree of graphitization, which in turn can be used to know the metamorphic degree of the host rock. The resulting RAMAN spectra of graphite were divided in first and second order regions, in the first region (1100-1800cm-1) the E2gvibration mode with D6hcrystal symmetry occurs at 1580cm-1(G band) that indicates poorly organized graphite, additional bands appears in the first order region at 1350 cm-1(D band) called the defect band, and another at 1620 cm-1(D* band). The second-order region (2200-3400cm-1) shows several bands at ~2400 ~2700 ~2900 ~3300cm-1, all of them attributed to electron-phonon interactions or combination scattering. The density functional theory calculations were applied to determine the vibrational properties and the stacking layers of graphite.
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Kolev, S. K., D. V. Trifonov, H. A. Aleksandrov, V. A. Atanasov, V. N. Popov, and T. I. Milenov. "DFT simulation of the Raman spectrum of single layer graphene." Journal of Physics: Conference Series 2487, no. 1 (May 1, 2023): 012003. http://dx.doi.org/10.1088/1742-6596/2487/1/012003.

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Abstract Raman spectroscopy is one of the most suitable tools for studying few-layer graphene. The position of the G band and the defect-induced D and D' bands in the spectra of perfect single-layer graphene with sp2-hybridized carbon atoms and hydrogenated graphene with 27.7% sp3-hybridized carbon atoms are simulated using the Density Functional Theory (DFT) method with Perdew-Burke-Ernzerhof (PBE) functional. In the case of perfect graphene, the Raman G band is predicted at 1612 cm-1. In the case of the hydrogenated structure, a new feature appears. Namely, along with the G band, now shifted to 1591 cm-1, an additional feature, located at 1703 cm-1, is clearly seen. The latter is due to oscillations, involving six atomic benzene rings, containing two sp3-hybridized C atoms. According to our results, the presence of defects, related to sp3 hybridized carbon, gives rise to the appearance of the defect D' band in the Raman spectrum of defective graphene. This study shows that it is possible to simulate Raman spectra using the DFT method, with the results qualitatively matching the experimental data.
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Lobban, A. P., S. Zola, U. Pajdosz-Śmierciak, V. Braito, E. Nardini, G. Bhatta, A. Markowitz, et al. "X-ray, UV, and optical time delays in the bright Seyfert galaxy Ark 120 with co-ordinated Swift and ground-based observations." Monthly Notices of the Royal Astronomical Society 494, no. 1 (March 4, 2020): 1165–79. http://dx.doi.org/10.1093/mnras/staa630.

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ABSTRACT We report on the results of a multiwavelength monitoring campaign of the bright, nearby Seyfert galaxy Ark 120, using a ∼50-d observing programme with Swift and a ∼4-month co-ordinated ground-based observing campaign, pre-dominantly using the Skynet Robotic Telescope Network. We find Ark 120 to be variable at all optical, UV, and X-ray wavelengths, with the variability observed to be well correlated between wavelength bands on short time-scales. We perform cross-correlation analysis across all available wavelength bands, detecting time delays between emission in the X-ray band and the Swift V, B, and UVW1 bands. In each case, we find that the longer wavelength emission is delayed with respect to the shorter wavelength emission. Within our measurement uncertainties, the time delays are consistent with the τ ∼ λ4/3 relation, as predicted by a disc reprocessing scenario. The measured lag centroids are τcent = 11.90 ± 7.33, 10.80 ± 4.08, and 10.60 ± 2.87 d between the X-ray and V, B, and UVW1 bands, respectively. These time delays are longer than those expected from standard accretion theory and, as such, Ark 120 may be another example of an active galaxy whose accretion disc appears to exist on a larger scale than predicted by the standard thin-disc model. Additionally, we detect further inter-band time delays: most notably between the ground-based I and B bands (τcent = 3.46 ± 0.86 d), and between both the Swift XRT and UVW1 bands and the I band (τcent = 12.34 ± 4.83 and 2.69 ± 2.05 d, respectively), highlighting the importance of co-ordinated ground-based optical observations.
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Wang, Tianzuo, Lun Pan, Xiangwen Zhang, and Ji-Jun Zou. "Insights into the Pt (111) Surface Aid in Predicting the Selective Hydrogenation Catalyst." Catalysts 10, no. 12 (December 16, 2020): 1473. http://dx.doi.org/10.3390/catal10121473.

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The d-band center position of the metal catalyst is one of the most important factors for catalytic selective hydrogenation, e.g., the conversion of nitrostyrene to aminostyrene. In this work, we modulate the d-band center position of the Pt surface via H coverage manipulation in order to assess the highly efficient selective hydrogenation catalyst using density functional theory (DFT) calculation, which is validated experimentally. The optimal transition metal catalysts are first screened by comparing the adsorption energy values of two ideal models, nitrobenzene and styrene, and by correlating the adsorption energy with the d-band center positions. Among the ten transition metals, Pt nanoparticles have a good balance between selectivity and the conversion rate. Then, the surface hydrogen covering strategy is applied to modulate the d-band center position on the Pt (111) surface, with the increase of H coverage leading to a decline of the d-band center position, which can selectively enhance the adsorption of nitro groups. However, excessively high H coverage (e.g., 75% or 100%) with an insufficiently low d-band center position can switch the chemisorption of nitro groups to physisorption, significantly reducing the catalytic activity. Therefore, a moderate d-band center shift (ca. −2.14 eV) resulted in both high selectivity and catalytic conversion. In addition, the PtSn experimental results met the theoretical expectations. This work provides a new strategy for the design of highly efficient metal catalysts for selective hydrogenation via the modulation of the d-band center position.
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Jiao, Shilong, Xianwei Fu, and Hongwen Huang. "Descriptors for the Evaluation of Electrocatalytic Reactions: d‐Band Theory and Beyond." Advanced Functional Materials 32, no. 4 (October 13, 2021): 2107651. http://dx.doi.org/10.1002/adfm.202107651.

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Dissertations / Theses on the topic "D-band Theory"

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Cao, Xiaodong [Verfasser], and Philipp [Akademischer Betreuer] Hansmann. "Extensions of dynamical mean-field theory to non-local correlations and multi-band systems / Xiaodong Cao ; Betreuer: Philipp Hansmann." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2019. http://d-nb.info/1217253378/34.

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Jeong, Sang Min. "Analysis of Vibration of 2-D Periodic Cellular Structures." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7122.

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The vibration of and wave propagation in periodic cellular structures are analyzed. Cellular structures exhibit a number of desirable multifunctional properties, which make them attractive in a variety of engineering applications. These include ultra-light structures, thermal and acoustic insulators, and impact amelioration systems, among others. Cellular structures with deterministic architecture can be considered as example of periodic structures. Periodic structures feature unique wave propagation characteristics, whereby elastic waves propagate only in specific frequency bands, known as "pass band", while they are attenuated in all other frequency bands, known as "stop bands". Such dynamic properties are here exploited to provide cellular structures with the capability of behaving as directional, pass-band mechanical filters, thus complementing their well documented multifunctional characteristics. This work presents a methodology for the analysis of the dynamic behavior of periodic cellular structures, which allows the evaluation of location and spectral width of propagation and attenuation regions. The filtering characteristics are tested and demonstrated for structures of various geometry and topology, including cylindrical grid-like structures, Kagom and eacute; and tetrhedral truss core lattices. Experimental investigations is done on a 2-D lattice manufactured out of aluminum. The complete wave field of the specimen at various frequencies is measured using a Scanning Laser Doppler Vibrometer (SLDV). Experimental results show good agreement with the methodology and computational tools developed in this work. The results demonstrate how wave propagation characteristics are defined by cell geometry and configuration. Numerical and experimental results show the potential of periodic cellular structures as mechanical filters and/or isolators of vibrations.
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Stadler, Katharina Maria [Verfasser], and Jan von [Akademischer Betreuer] Delft. "A model study of strong correlations in Hund metals : the Numerical Renormalization Group as efficient multi-band impurity solver for Dynamical Mean-Field Theory / Katharina Maria Stadler ; Betreuer: Jan von Delft." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2019. http://d-nb.info/1182228690/34.

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Greif, Ludwig Albrecht Theodor [Verfasser], Axel [Akademischer Betreuer] Hoffmann, Axel [Gutachter] Hoffmann, and der Maur Matthias [Gutachter] Auf. "Quantum dots and quantum wires and their usage in future optoelectronic devices in the framework of 8-band kp-theory / Ludwig Albrecht Theodor Greif ; Gutachter: Axel Hoffmann, Matthias Auf der Maur ; Betreuer: Axel Hoffmann." Berlin : Technische Universität Berlin, 2019. http://d-nb.info/1200018214/34.

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Ahmad, Rafia. "Overcoming Challenges Associated with Hydrogen Storage Efficiency and Fuel Cell Catalysis : An Ab Initio Study." Thesis, 2017. http://etd.iisc.ac.in/handle/2005/4301.

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Fuel cells offer the best solution to the imminent energy and environmental crisis staring at our face, urging the scientific community to overcome all the challenges faced by its effective commercialization. These harness the power of hydrogen, which requires efficient methods to store hydrogen reversibly. Fuel cells have been known to function the best while employing Pt as the catalyst. An acute setback to the coherent working of a fuel cell is the degradation of expensive and scarce Pt catalyst by CO. Converting this CO to CO2 through fast reaction kinetics promises an answer to this vital issue. However, CO2 production will further increase its concentration in the atmosphere undesirably adding to the steady emissions from consumption of fast depleting fossil fuels. Consequently, global warming will accelerate, which threatens the sustainability and prosperity of the society. Converting CO2 to value-added products should solve both fossil-fuel shortage and anomalous climate change. Storing energy in chemical bonds, as fuels such as CH4, and finding an electrochemical catalyst to reduce CO2 to such hydrocarbon fuels would provide an ideal solution for discontinuous renewable energy sources. This thesis effectively addresses these major issues faced by a successful global implementation of fuel cells and sustainable energy. The reported results and findings provide a better understanding of materials properties, which can be generalized to other systems as well. The thesis has been organized as follows: Chapter 1 introduces fuel cells and heterogeneous catalysis, challenges associated with their large-scale commercialization, and pathways to achieve optimized catalytic and hydrogen storage performance. An overview of importance of nanoparticles in heterogeneous catalysis is given along with traditional methods followed to parametrize and evaluate hydrogen storage and catalytic efficiencies. The motivation of the research work has been highlighted in this chapter. Chapter 2 describes the theoretical methodology employed for the work. It gives an understanding of first principles-based Density Functional Theory (DFT) and various exchange and correlation energy functional used to obtain electronic and structural information. Theory underlying the methods employed for computationally calculating reaction energy pathways, barriers, rates, and turnover frequency are also described briefly. Chapter 3 proposes a strategy to enhance the hydrogen storage properties of transition metal clusters. Doping of small Ti clusters by B, enhances their reversible hydrogen storage capacity. Among all Tin−1B (n = 3, 4, 5, 6, and 7) clusters, Ti3B stores the maximum number of 12 H2 molecules (three dissociated and nine Kubas type). The best capacity of Ti3B originates from the combined effect of a large charge transfer from Ti to B and a high localization of Ti empty d states at a large distance above the Fermi-level. For Ti3 anchored to B of BC3, the number of Kubas-bound hydrogen remains the same as that of the free-standing Ti3B, while the unusable chemisorbed hydrogen are absent. Gibbs energy of adsorption as a function of H2 partial pressure shows that Ti3@BC3 adsorbs and desorbs nine Kubas-bound hydrogen at ambient pressures and room temperature. Chapter 4 investigates the problem of O2 interference in hydrogen storage on metal decorated carbonaceous systems, which remains one of the major stumbling blocks in the successful realization of the theoretically promised high storage of Kubas bound H2. The interference is a consequence of preferred O2 binding at the metal site, thereby blocking it for H2 adsorption. Arene capping of a Sc-metallocarbene (MCB) efficiently reverses the preferential adsorption of O2 over H2. The capped Sc-MCB completely repels O2 off the Sc-site allowing solely Kubas binding of H2, consequent of the down-shift of the d-band center of Sc from 1.29 eV in the uncapped to 5.67 eV in the capped MCB, below the Fermi-level, respectively. This optimized d-band center position enables the empty Sc antibonding states to only be available for hydrogen adsorption via Kubas interaction, thereby, to completely avoid oxygen binding. Chapter 5 shows for the first time that on supported Pt3Co/MgO(100), the preferred CO adsorption site inverts to Co from Pt. This inversion results from the better availability of empty anti-bonding d-states of Co atom in Pt3Co than those of the Pt atoms. The d-band center has a one-to-one correlation with CO adsorption energy and its relative position determines the adsorption site. Furthermore, for Mars van Krevelan (MvK) mechanism of CO oxidation on Pt3Co /Li-doped MgO(100), low reaction barrier of 0.11 eV predicts excellent reaction kinetics. A novel design strategy of d-band center inversion for CO oxidation catalysts with no Pt poisoning and excellent reaction kinetics is proposed. Chapter 6 extends the search for bimetallic Pt clusters, which possess the CO adsorption site inversion properties inherently. Among all 3d transition metals (M) in Pt3M, only V d- band center is closer to the Fermi level than that of Pt. This leads to a larger affinity of V towards CO, making it more reactive than Pt. The relative position of d-band center from Fermi-level describes the favorable adsorption site in a system. The d- band center position of only the V atom (among all M = Sc, Ti, V, Mn, Fe, Co, Ni, Cu, and Zn) is closer to the Fermi level than that of the Pt atoms, increasing its preference towards CO. Furthermore, anchoring Pt3V on Li-doped MgO(100) activates a spontaneous oxygen vacancy, oxidizing CO via small reaction barrier of 0.13 eV, exhibiting better reaction kinetics than the free-standing cluster. Chapter 7 elucidates the prospect of tuning catalytic processes as a function of cluster size, which has been a long-sought goal in heterogeneous catalysis. Ptn(V/Co)m, for (n m = 4, 2; 9, 3; 15, 5; 41, 14; and 59, 20) are studied as CO oxidation catalysts. The site inversion is preserved for the CO adsorption on V for all PtnVm. This inversion to Co from Pt is introduced beyond 12-atom cluster for PtnCom. A subsequent peroxo-like O2 adsorption after CO, on the adjacent Pt sites leads to the efficient oxidation of CO to CO2 with low Langmuir-Hinshelwood (L-H) mechanism barriers. The maximized catalytic activity is observed for the 55-atom cluster of Pt41(V/Co)14 pertaining to the optimal CO binding and best reaction kinetics. Finally, MvK mechanism of CO oxidation on Pt41V14/Li-doped MgO(100) proceeds via low reaction barrier of 0.14 eV, promising efficient CO oxidation catalytic activity. Chapter 8 exhibits insights into low and ambient temperature CO oxidation catalytic activities of Pt plates supported on reconstructed Si 7×7 (111) surface. The catalytic activity of CO oxidation over Pt/Si 7 × 7 (111) reconstructed surface with restricted platinum loading is analysed. We report, tuning of CO oxidation catalytic activity with size of single-layered platinum clusters Ptn/Si-RS (n = 10, 20, 30, and 45). The catalytic performance varies for Ptn plates, which is a consequence of the different interactions between Pt and Si-RS with changing n. The distance of d-band centers of Ptn/Si-RS from π orbitals of CO and O2 correlates with the strength of adsorption energy as n changes. The reaction kinetics analysis reveals that more than 10 CO2 molecules can be produced via CO oxidation on Ptn/Si-RS. This turn over frequency of CO2 exceeds that of the conventional CO oxidation catalysts. The results of this work will lead to the effective use of platinum and Si 7×7 (111) components at ambient atmospheres to design CO tolerant catalysts and ensure its fast oxidation. Chapter 9 presents a facile solution to the enormous problem of efficient CO2 mitigation, utilizing the knowledge of increasing catalytic efficiency by employing trimetallic nanoparticles. DFT calculations in combination with the computational hydrogen electrode (CHE) model develop a detailed description of the free-energy landscape and limiting potential for NiTM@Cu (TM = 3d transition metals) alloy core shell nanoparticles. An overview of the thermodynamics of CO2 conversion to CH4 as a function of limiting potential establishes that these alloy core shell catalysts promise excellent CO2 reduction at overpotentials as low as 0.17 V with respect to the equilibrium potential or standard potential value (SPV). This efficiency stems from the fact that the rate limiting step of CO protonation to CHO has small exothermicity, especially for the early transition metals (Sc, Ti, and V). Furthermore, the better stabilization of CHO than CO on the NiTM@Cu core-shell catalysts makes the vastly reported rate limiting step of CO protonation exergonic at very small overpotentials. The chapter also establishes that the limiting potential can be tuned by varying the core composition in Ni13−xMx@Cu, in turn affecting the catalytic activity. The complete reaction profile of CO2 electro-reduction in the presence of water affects the binding energies. Moreover, the intrinsic solvation effect does not relatively change the reaction pathways and overpotential values. Chapter 10 summarizes and concludes the work presented in this thesis in addition to a brief description of future projects.
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Bartenschlager, Sonja [Verfasser]. "Quantenmechanische Theorie zur d-Band-Katalyse des elektrochemischen Elektronentransfers mit Bindungsbruch / vorgelegt von Sonja Bartenschlager." 2009. http://d-nb.info/999656538/34.

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Lindner, Marko [Verfasser]. "Fredholm theory and stable approximation of band operators and their generalisations / von Marko Lindner." 2009. http://d-nb.info/996253513/34.

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Taubitz, Christian. "Investigation of the magnetic and electronic structure of Fe in molecules and chalcogenide systems." Doctoral thesis, 2010. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-201006096312.

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In this work the electronic and magnetic structure of the crystals Sr2FeMoO6, Fe0.5Cu0.5Cr2S4, LuFe2O4 and the molecules FeStar, Mo72Fe30, W72Fe30 are investigated by means of X-ray spectroscopic techniques. These advanced materials exhibit very interesting properties like magnetoresistance or multiferroic behaviour. In case of the molecules they also could be used as spin model systems. A long standing issue concerning the investigation of these materials are contradicting results found for the magnetic and electronic state of the iron (Fe) ions present in these compounds. Therefore this work focuses on the Fe state of these materials in order to elucidate reasons for these problems. Thereby the experimental results are compared to multiplet simulations.
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Books on the topic "D-band Theory"

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NATO Advanced Research Workshop on Narrow-Band Phenomena--Influence of Electrons with Both Band and Localized Character (1987 Staverden, Netherlands). Narrow-band phenomena--influence of electrons with both band and localized character. New York: Plenum Press, 1988.

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Conduction in non-crystalline materials. Oxford: Clarendon Press, 1987.

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F, Mott N. Conduction in non-crystalline materials. 2nd ed. Oxford: Clarendon Press, 1993.

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1936-1984, McMillan William L., Hutiray Gy, So lyom J, and International Conference on Charge Density Waves in Solids (1984 : Budapest, Hungary)., eds. Charge density waves in solids: Proceedings of the International Conference held in Budapest, Hungary, September 3-7, 1984. Berlin: Springer-Verlag, 1985.

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Density waves in solids. Reading, Mass: Addison-Wesley Pub. Co., Advanced Book Program, 1994.

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Solymar, L. Solutions manual for Lectures on the electrical properties of materials. Oxford: Oxford University Press, 1993.

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Solymar, L. Lectures on the electrical properties of materials. 4th ed. Oxford: Oxford University Press, 1988.

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Electronic properties of materials: An introduction for engineers. Berlin: Springer-Verlag, 1985.

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Electronic properties of materials. 3rd ed. New York: Springer, 2001.

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Electronic properties of materials. 2nd ed. Berlin: Springer-Verlag, 1992.

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Book chapters on the topic "D-band Theory"

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Mel’nikov, Alexander S. "Band Theory of Quasiparticle Excitations in the Mixed State of d-Wave Superconductors." In Springer Series in Solid-State Sciences, 207–24. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-662-04665-4_12.

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Gosavi, Hrishikesh S., Phanisri P. Pratapa, and Vijaya V. N. Sriram Malladi. "Band Gap Estimation of D-LEGO Meta-structures Using FRF-Based Substructuring and Bloch Wave Theory." In Conference Proceedings of the Society for Experimental Mechanics Series, 41–47. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-04094-8_5.

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Moriarty, John A. "Interatomic Potentials in Metals with Empty or Filled d Bands." In Theory and Application of Quantum-Based Interatomic Potentials in Metals and Alloys, 135–75. Oxford University PressOxford, 2023. http://dx.doi.org/10.1093/oso/9780198822172.003.0004.

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Abstract In this chapter, quantum-based interatomic potentials are derived for the d-band metals at the beginning and end of each transition series, using generalized pseudopotential theory (GPT). Ideally, such materials have either empty d bands above the Fermi level (e.g., Ca) or filled d bands below the Fermi level (e.g., Zn). The important new physics in these systems is the sp-d hybridization of the nearly free-electron sp valence bands with the narrow d bands, physics which can still be captured in the real-space cohesive-energy functional at the pair-potential level. An accurate treatment of the sp-d hybridization, however, requires an optimum choice of the d basis state in the GPT, which is achieved through machine learning and has been accomplished for Ca, Sr, Zn, Cd and Hg. The remaining candidate metals Ba, Cu, Ag and Au are best treated as transition metals with partial d-band filling, as discussed in Chapter 5, although for the noble metals a modified filled-d-band GPT treatment has shown some success, as has the alternate resonant model potential treatment of Dagens et al.
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Moriarty, John A. "Fundamental Principles in Metals Physics." In Theory and Application of Quantum-Based Interatomic Potentials in Metals and Alloys, 35–90. Oxford University PressOxford, 2023. http://dx.doi.org/10.1093/oso/9780198822172.003.0002.

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Abstract In this chapter, the underlying fundamental principles in metals physics necessary to develop quantum-based interatomic potentials in subsequent chapters are discussed. Density functional theory (DFT) is reviewed together with guidance from DFT electronic-structure calculations for both prototype simple metals and d-band transition metals. The nearly free electron (NFE) nature of the valence energy bands in simple metals allows a quantum treatment of the cohesive-energy functional within a plane wave basis set and the use of pseudopotential perturbation theory. The narrow d bands of transition series metals can be treated in a tight-binding (TB) representation with localized d basis states and simplified canonical d bands. The full hybrid NFE-TB nature of d-band metals, including sp-d hybridization, can be accommodated in a mixed basis set of plane waves and localized d states through the use of generalized pseudopotential theory, which is developed from a rigorous pseudo-Green’s function approach applied to DFT.
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Moriarty, John A. "Extension to f-Band Actinide Metals and p-Band Simple Metals." In Theory and Application of Quantum-Based Interatomic Potentials in Metals and Alloys, 480–92. Oxford University PressOxford, 2023. http://dx.doi.org/10.1093/oso/9780198822172.003.0012.

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Abstract In this chapter, the generalized pseudopotential theory (GPT) of quantum-based interatomic potentials is extended beyond its usual treatment of d-band transition-series metals to f-band actinide metals, and also to possible strong bonding p-band simple metals. This extension is possible because the underlying pseudo-Green’s function formalism from which the GPT was developed in a plane-wave, localized d-state basis does not actually impose any symmetry requirement on the character of the localized basis states. Thus, the GPT formalism can be immediately extended to include, in addition to plane waves, localized p or f states. In practice, such an extension is most easily accomplished in the context of the simplified model-GPT (MGPT), with the canonical d-band formalism developed in Chapter 5 acting as a prototype for corresponding canonical p-band and f-band treatments. Here, the canonical f-band MGPT treatment has been successfully applied to uranium. A novel MGPT treatment, with the normal f bonding turned off to simulate strong electron correlation, also explains the low-density delta phase of plutonium.
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Khaneja, Navin. "SQUID Magnetometers, Josephson Junctions, Confinement and BCS Theory of Superconductivity." In Magnetometers - Fundamentals and Applications of Magnetism. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.83714.

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A superconducting quantum interference device (SQUID) is the most sensitive magnetic flux sensor currently known. The SQUID can be seen as a flux to voltage converter, and it can generally be used to sense any quantity that can be transduced into a magnetic flux, such as electrical current, voltage, position, etc. The extreme sensitivity of the SQUID is utilized in many different fields of applications, including biomagnetism, materials science, metrology, astronomy and geophysics. The heart of a squid magnetometer is a tunnel junction between two superconductors called a Josephson junction. Understanding the work of these devices rests fundamentally on the BCS theory of superconductivity. In this chapter, we introduce the notion of local potential and confinement in superconductivity. We show how BCS ground state is formed from interaction of wave packets confined to these local potential wells. The starting point of the BCS theory of superconductivity is a phonon-mediated second-order term that describes scattering of electron pair at Fermi surface with momentum k i , − k i and energy 2 ℏ ω i to k j , − k j with energy 2 ℏ ω j . The transition amplitude is M = − d 2 ω d ω i − ω j 2 − ω d 2 , where d is the phonon scattering rate and ω d is the Debye frequency. However, in the presence of offset ω i − ω j , there is also a present transition between states k i , − k i and k j , − k i of sizable amplitude much larger than M . How are we justified in neglecting this term and only retaining M ? In this chapter, we show all this is justified if we consider phonon-mediated transition between wave packets of finite width instead of electron waves. These wave packets are in their local potentials and interact with other wave packets in the same well to form a local BCS state we also call BCS molecule. Finally, we apply the formalism of superconductivity in finite size wave packets to high Tc in cuprates. The copper electrons in narrow d-band live as packets to minimize the repulsion energy. The phonon-mediated coupling between wave packets (of width Debye energy) is proportional to the number of k-states in a packet, which becomes large in narrow d-band (10 times s-band); hence, d-wave Tc is larger (10 times s-wave). At increased doping, packet size increases beyond the Debye energy, and phonon-mediated coupling develops a repulsive part, destroying superconductivity at large doping levels.
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Zaier, Rania, and Sahbi Ayachi. "Designing Well-Organized Donor-Bridge-Acceptor Conjugated Systems Based on Cyclopentadithiophene as Donors in Bulk Heterojunction Organic Solar Cells: DFT-Based Modeling and Calculations." In Solar Cells - Theory, Materials and Recent Advances. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.94874.

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Two host materials based on CPDT as donors in bulk heterojunction organic solar cells were designed and investigated by means of DFT calculations. The first one (P-CPDTBT3) is a copolymer with D-A configuration and the second one (SM-CPDTDPP) is a D-π-A-π-D type small molecule. The investigated materials exhibited interesting structural properties with high planarity and rigidity originated from intra-molecular non-covalent interactions between the different building blocks. Thanks to their narrow band gaps, the optical absorption spectra have covered the main part of solar spectrum of interest. In addition, some general transport properties have been established. The transition density matrix (TDM) was used to get insight into the interaction of hole–electron localization and the electronic excitation processes. The photovoltaic parameters (FF, Voc) were calculated. The obtained results have been attempted to provide novel structure–property relationships for the rational design strategies of high-performance photovoltaic materials with power conversion efficiency of nearly 10%.
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Zaier, Rania, and Sahbi Ayachi. "Computational Study on Optoelectronic Properties of Donor-Acceptor Type Small π-Conjugated Molecules for Organic Light-Emitting Diodes (OLEDs) and Nonlinear Optical (NLO) Applications." In Density Functional Theory - Recent Advances, New Perspectives and Applications. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.98590.

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Recently, donor-acceptor type molecule that contains electron-rich (D) and electron-deficient (A) moiety has emerged as an interesting approach of molecular design strategy to develop organic light-emitting diodes (OLEDs) and non-linear optical (NLO) devices. In this work, we report a theoretical investigation based on two donor-acceptor (D-A) type small π-conjugated molecules based on dithieno [3,2-b: 2′,3′-d] pyrrole (DTP) and anthracene derivatives. All of the theoretical calculations were performed by Density Functional Theory (DFT) approach at B3LYP/6-31 g(d) level of theory. The structural, electronic, optical and charge transfer properties were investigated. The effect of acceptor blocks (DPA and DTA) on the molecular characteristics was elucidated. The obtained results clearly show that the studied compounds exhibit non-coplanar structures with low electronic band gap values. These relevant structures exhibited important optical absorption and intense emission in the green-yellow region. NLO investigation based on static polarizability (α0), first-order hyperpolarizability (β0) and second-order hyperpolazabilty (ɣ0) demonstrated that the studied materials exhibit excellent NLO properties. Thus, the designed materials showed promising capabilities to be utilized in OLED and NLO applications.
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Moriarty, John A. "Interatomic Potentials with Electron Temperature." In Theory and Application of Quantum-Based Interatomic Potentials in Metals and Alloys, 493–507. Oxford University PressOxford, 2023. http://dx.doi.org/10.1093/oso/9780198822172.003.0013.

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Abstract In Chapters 7 and 8, the high temperature (T) properties of metals were treated in the conventional weak-coupling limit, where zero-T quantum-based interatomic (QBIPs) are applied to obtain the thermal components of thermodynamic properties in the solid as well as the liquid. In this chapter, we consider the alternative strong-coupling limit, where the ion and electron temperatures are treated on an equal footing, leading to explicit T-dependent QBIPs. Such a strong-coupling treatment can be important for narrow-band 3d and 4d transition metals near melt due to their high density of electronic states and corresponding large observed specific heats. Here the generalized pseudopotential theory (GPT) of QBIPs is first extended to finite electron temperature within the rigorous Mermin formulation of density functional theory. For a Mo prototype, T-dependent model-GPT potentials have then been developed for optimized noncanonical d bands and applied to the simulation of the high-pressure melt curve, a result that is found to be in excellent agreement with both experiment and full quantum molecular dynamics simulations.
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Mar, Winnie A., and Eléonore Blondieux. "Hypervitaminoses, Hypovitaminoses, Fluorosis, and Lead Poisoning." In Musculoskeletal Imaging Volume 2, edited by Mihra S. Taljanovic and Tyson S. Chadaz, 319–21. Oxford University Press, 2019. http://dx.doi.org/10.1093/med/9780190938178.003.0117.

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Chapter 116 discusses hypervitaminoses, including hypervitaminosis A and D, and hypovitaminoses, particularly scurvy and its effects on the musculoskeletal system. Fluoride and lead poisoning are also discussed. The pathophysiology of these diseases and imaging findings are delineated. The main imaging findings of hypervitaminosis A are wavy metaphyseal periostitis in children and enthesopathy in adults. Metastatic calcification is seen with hypervitaminosis D. In scurvy, there is a dense line of the physis, at the zone of provisional calcification, and a lucent metaphyseal band, with possible periosteal elevation caused by subperiosteal hemorrhage. In fluorosis, there is increased bone density and periostitis. In lead poisoning, there are dense metaphyseal bands.
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Conference papers on the topic "D-band Theory"

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Kumar, Meena R., Dilip Kumar, and A. K. Shukla. "Development of D-band Gunn oscillator." In 2008 International Conference on Recent Advances in Microwave Theory and Applications (MICROWAVE). IEEE, 2008. http://dx.doi.org/10.1109/amta.2008.4763130.

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Yablonovitch, Eli. "Photonic band structure: the band theory of light in 3-D dielectric structures." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1987. http://dx.doi.org/10.1364/oam.1987.mr11.

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By analogy to electron waves in a crystal, light waves in a 3-D periodic dielectric structure should be described by band theory. Recently, the idea of the photonic band structure1 has been introduced, meaning that the concepts of reciprocal space, Brillouin zones, dispersion relations, Bloch wave functions, Van Hove singularities, etc. can now be applied to optical waves. If the depth of index of refraction modulation is sufficient, a photonic band gap can exist. This is an energy band in which optical modes, spontaneous emission, and zero point fluctuations are all absent. Therefore, inhibited spontaneous emission can now begin to play a role in semiconductors and solid-state electronics.
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Li, Juan, Li-Xin Guo, and Ke Li. "Wide-band scattering of 1-D dispersive soil surface." In 2012 10th International Symposium on Antennas, Propagation & EM Theory (ISAPE - 2012). IEEE, 2012. http://dx.doi.org/10.1109/isape.2012.6408865.

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Yang, Dandan, Jincai Wen, Meilin He, and Ruicong He. "A D-band Monolithic Low Noise Amplifier on InP HEMT Technology." In 2018 12th International Symposium on Antennas, Propagation and EM Theory (ISAPE). IEEE, 2018. http://dx.doi.org/10.1109/isape.2018.8634087.

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Sukharevsky, Oleg I., and Gennady S. Zalevsky. "3-D Electromagnetic Scattering by Ellipsoidal Silver Nanoparticles in Optical Band." In 2018 IEEE 17th International Conference on Mathematical Methods in Electromagnetic Theory (MMET). IEEE, 2018. http://dx.doi.org/10.1109/mmet.2018.8460294.

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Wu, Tao, Zhensen Wu, Yinyu Wei, and Xiaoxiao Zhang. "The analysis on Doppler spectrum of 2-D sea clutter in multi-band." In 2016 11th International Symposium on Antennas, Propagation and EM Theory (ISAPE). IEEE, 2016. http://dx.doi.org/10.1109/isape.2016.7834013.

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Zhang, Fan, Lili Xu, Jianqiang Zhang, Pulong Nan, Xiaofan Jin, and Gaofeng Pan. "A 3-D Printed Ka-Band Waveguide Bandpass Filter With Quasi-Elliptic Response." In 2021 13th International Symposium on Antennas, Propagation and EM Theory (ISAPE). IEEE, 2021. http://dx.doi.org/10.1109/isape54070.2021.9753345.

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Yablonovitch, Eli. "Photonic band structure." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.me1.

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By analogy to electron waves in a crystal, electromagnetic waves in a 3-D periodic dielectric structure should be described by band theory. The idea of photonic band structure1 is rapidly2–5 gaining acceptance. The concepts of reciprocal space, Brillouin zones, dispersion relations, Bloch wave functions, Van Hove singularities, etc., are now being applied to optical waves. If the depth of refraction index modulation is sufficient, a photonic band gap can exist. This is a frequency band in which electromagnetic modes, spontaneous emission, and zero point fluctuations are all absent. Indeed, a photonic band gap cam be essentially ideal provided the dielectric response is real and dissipationless. In addition to the obvious uses in atomic and laser physics, photonic band structure can now begin to play a role in microwave and millimeter wave electronics. Defects can be introduced into the otherwise perfect 3-D structures, creating electromagnetic donor modes and acceptor modes. Effectively, these defects are purely dielectric single-mode high-Q cavities suitable for a range of frequencies from microwaves to the visible. At the outset it was realized1 that a face-centered-cubic (FCC) array in real space would produce the most spherelike Brillouin zone in reciprocal space. This spherelike geometry increased the likelihood that a forbidden gap would overlap all the way around the surface of the Brillouin zone. But is was unclear what should be the shape in real space of the atoms in this FCC array. The history of this field has been a search for that optimal 3-D dielectric geometry, favored by nature and by Maxwell’s equations. During this same period, electronic band theorists began calculating photonic band structure. It rapidly became apparent that the familiar scalar wave band theory, so frequently used for electrons in solids, was in utter disagreement with experiment on photons.7–10 Recently3–5 a full vector-wave band theory became available, which not only agreed with experiment, it successfully highlighted some discrepancies in the experiment.
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Yuan, Jing, and Hongxia Ye. "Beam Simulation and Band-limited Matrix Decomposition for Fast Imaging of 1-D Random Rough Surface." In 2018 12th International Symposium on Antennas, Propagation and EM Theory (ISAPE). IEEE, 2018. http://dx.doi.org/10.1109/isape.2018.8634163.

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Koch, Stephan W., Hartmut Haug, and Murray Sargent. "Semiconductor laser theory with many-body effects." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1988. http://dx.doi.org/10.1364/oam.1988.mj5.

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A theory of a semiconductor laser is developed that includes the many-body effects due to Coulomb interactions. The theory is valid for both 3-D bulk semiconductors as well as quasi-2-D quantum well structures. We emphasize plasma density-dependent band gap renormalization, broadening due to intraband scattering, and electron–hole Coulomb enhancement. The very short intraband scattering relaxation time allows us to eliminate the interband polarization adiabatically and to introduce a hydrodynamic description of the intraband kinetics. From this general formulation a diffusion equation for the carrier density is derived. The resulting diffusion coefficient decreases with carrier density and laser intensity due to the reduction of the electron drift. We use our theory in the problem of laser gain, index, and side mode instabilities. We show that near the laser operating point, our many-body theory can be approximated by a simple rate equation formalism. However, in contrast to the usual rate-equation theory, the semiconductor rate constants are functions of temperature, tuning, and carrier density.
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Reports on the topic "D-band Theory"

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Nin Pratt, Alejandro, Gert-Jan Stads, Luis de los Santos, and Gonzalo Muñoz. Unlocking Innovation: Assessing the Role of Agricultural R&D in Latin America and the Caribbean. Inter-American Development Bank, July 2023. http://dx.doi.org/10.18235/0005006.

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This report presents a comprehensive analysis of public agricultural research and development (R&D) in Latin America and the Caribbean (LAC), focusing on the contextual factors influencing agricultural R&D investment and their implications for agricultural productivity growth. The analysis combines new data for ten LAC countries collected by the International Food Policy Research Institute's (IFPRI's) Agricultural Science and Technology Indicators (ASTI) program with support from the Inter-American Development Bank (IDB), with existing ASTI and other datasets. By integrating these various datasets, the report provides an in-depth examination of recent trends in public agricultural research spending, capacity, and outputs across the LAC region.
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Pritchett, Lant, and Martina Viarengo. Learning Outcomes in Developing Countries: Four Hard Lessons from PISA-D. Research on Improving Systems of Education (RISE), April 2021. http://dx.doi.org/10.35489/bsg-rise-wp_2021/069.

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The learning crisis in developing countries is increasingly acknowledged (World Bank, 2018). The UN’s Sustainable Development Goals (SDG) include goals and targets for universal learning and the World Bank has adopted a goal of eliminating learning poverty. We use student level PISA-D results for seven countries (Cambodia, Ecuador, Guatemala, Honduras, Paraguay, Senegal, and Zambia) to examine inequality in learning outcomes at the global, country, and student level for public school students. We examine learning inequality using five dimensions of potential social disadvantage measured in PISA: sex, rurality, home language, immigrant status, and socio-economic status (SES)—using the PISA measure of ESCS (Economic, Social, and Cultural Status) to measure SES. We document four important facts. First, with the exception of Ecuador, less than a third of the advantaged (male, urban, native, home speakers of the language of instruction) and ESCS elite (plus 2 standard deviations above the mean) children enrolled in public schools in PISA-D countries reach the SDG minimal target of PISA level 2 or higher in mathematics (with similarly low levels for reading and science). Even if learning differentials of enrolled students along all five dimensions of disadvantage were eliminated, the vast majority of children in these countries would not reach the SDG minimum targets. Second, the inequality in learning outcomes of the in-school children who were assessed by the PISA by household ESCS is mostly smaller in these less developed countries than in OECD or high-performing non-OECD countries. If the PISA-D countries had the same relationship of learning to ESCS as Denmark (as an example of a typical OECD country) or Vietnam (a high-performing developing country) their enrolled ESCS disadvantaged children would do worse, not better, than they actually do. Third, the disadvantages in learning outcomes along four characteristics: sex, rurality, home language, and being an immigrant country are absolutely large, but still small compared to the enormous gap between the advantaged, ESCS average students, and the SDG minimums. Given the massive global inequalities, remediating within-country inequalities in learning, while undoubtedly important for equity and justice, leads to only modest gains towards the SDG targets. Fourth, even including both public and private school students, there are strikingly few children in PISA-D countries at high levels of performance. The absolute number of children at PISA level 4 or above (reached by roughly 30 percent of OECD children) in the low performing PISA-D countries is less than a few thousand individuals, sometimes only a few hundred—in some subjects and countries just double or single digits. These four hard lessons from PISA-D reinforce the need to address global equity by “raising the floor” and targeting low learning levels (Crouch and Rolleston, 2017; Crouch, Rolleston, and Gustafsson, 2020). As Vietnam and other recent successes show, this can be done in developing country settings if education systems align around learning to improve the effectiveness of the teaching and learning processes to improve early learning of foundational skills.
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