Materials Literature
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Organic derivatives of a layered perovskite compound, HLaNb 2 O 7 · x H 2 O (HLN), with interlayer surfaces possessing n -alkoxyl groups ( n -decoxyl and n -propoxyl) have been allowed to react with various alcohols and a diol (ethylene glycol) to form new organic derivatives via substitution reactions. The reaction o…
By employing monomer-resolved Monte Carlo simulations, we analyze the conformations, density distributions, correlation functions, and the form factor of model dendrimers of fourth generation. We find that these objects are hybrids between polymer chains and compact colloidal particles, with the fluctuations of the mo…
Crown-annelated quater- (4T) and sexithiophenes (6T) with oligooxyethylene chains of various lengths attached at the 3-positions of the terminal thiophene rings have been synthesized. Analysis of the cation-binding properties of the macrocycles by (1)H NMR and UV-vis spectroscopy reveals the formation of a 1:1 complex…
We report on the interface properties of thermally oxidized n-GaN metal–oxide–semiconductor capacitors fabricated on sapphire substrates. 100-nm-thick β-Ga2O3 was grown by dry oxidation at 880 °C for 5 h. From secondary ion mass spectrometry measurements, an intermediate Ga oxynitride layer with graded compositions is…
Self-organized single crystalline two-dimensional hexagonal arrays of pores in InP semiconductor compound are reported. We show that the self-arrangement of pores can be obtained on n-type substrates with (100) and (111) orientations. The long-range order in pore distribution evidenced in (100)InP samples proves to be…
The 3D-hexagonal mesoporous films are used as templates to grow uniform silver nanoparticles. The grafting of hydrophobic groups at the pore surface, significantly slows down the silver ion diffusion, anchoring small silver clusters in micropores and leading to organized domains of silver particles in mesopores with a…
We have fabricated a single-wall carbon-nanotube (CNT)-based nonvolatile memory device using SiO2–Si3N4–SiO2 (ONO) layers as a storage node. The memory device is composed of a top gate structure with a channel width of a few nanometers and the ONO layer embedded between CNT and gate electrode. When the bias voltage be…
Structural and dynamic properties of cristobalite silica have been studied using molecular dynamics simulations based on a charge transfer three-body potential model. In this potential model, the directional covalent bonding of SiO2 is characterized by a charge transfer function of the interatomic distance between Si…
The theoretical investigation of mesoscopic objects requires new techniques which are particularly suited for the study of selected aspects of these systems. Vibrational spectroscopy is a main source for structural information on heterogeneous systems. We present an efficient quantum chemical method, which relies on a…
The shock-wave resistance of WS(2) nanotubes has been studied and compared to that of carbon nanotubes. Detailed structural features of post-shock samples were investigated using HRTEM, XRD, and Raman spectroscopy. WS(2) nanotubes are capable of withstanding shear stress caused by shock waves of up to 21 GPa, although…
We have measured the dielectric relaxation of several molecular organic supercooled liquids, ααβ-tris-naphthylbenzene (C36H24 and C36H10D14), squalane, and decahydroisoquinoline. The dynamics is studied in the frequency range 10−2–107 Hz, equivalent to temperatures between Tg and approximately 1.2×Tg. For the very low…
We report on the spin-polarized electron injection through an Fe(100)/InAs(100) junction. The circularly polarized electroluminescence of injected electrons from epitaxially grown Fe thin film into InAs(100) in an external magnetic field is measured to investigate the spin injection efficiency. The obtained polarizati…
Mn 2p soft X-ray absorption (XAS) spectroscopy excited with circularly polarized synchrotron radiation has been applied to a new class of material, c(2x2)CuMn/Cu(001) two-dimensional ordered surface alloy. A significant X-ray magnetic circular dichroism (XMCD) signal has been clearly observed at T=25K, indicating the…
Phase diagrams for single bubble sonoluminescence (SBSL) are calculated. The employed model is based on a set of ordinary differential equations and accounts for the bubble hydrodynamics, heat exchange, phase change of water vapor, chemical reactions of the various gaseous species in the bubble (N2, O2, and H2O being…
The expulsion dynamics of the last liquid monolayer of molecules confined between two surfaces has been analyzed by solving the two-dimensional (2D) Navier-Stokes equation for a compressible liquid. We find that the squeeze-out is characterized by the parameter g0 ~ P0/(rho c^2), where P0 is the average perpendicular…
Starch, one of the most inexpensive and most readily available of all natural polymers, can be processed into thermoplastic materials only in the presence of plasticizers and under the action of heat and shear. Poor water resistance and low strength are limiting factors for the use of materials manufactured only from…
We study the binding of molecular oxygen to a graphene sheet and to a (8,0) single walled carbon nanotube, by means of spin-unrestricted density-functional calculations. We find that triplet oxygen retains its spin-polarized state when interacting with graphene or the nanotube. This leads to the formation of a weak bo…
The subwavelength imaging quality of a metamaterial superlens is studied numerically in the wave vector domain. Examples of image compression and magnification are given and resolution limits are discussed. A minimal resolution of λ/6 is obtained using a 36 nm silver film at 364 nm wavelength. Simulation also reveals…
Mechanistic models for ethylene copolymerization with Ziegler–Natta catalysts contain many kinetic rate constants. Precise estimates of key parameters are required if the models are to be used to obtain reliable predictions of polymer properties for a specified catalyst over a range of polymerization conditions. In th…
The difference between oxide and hydrogen passivation of small Si nanocrystals is explored by all-electron, hybrid functional DFT calculations with unrestricted geometry optimization. Oxide passivation lowers the band gap by about 2.4 eV for Si 35 cores and by about 1.5 eV for Si 66 cores. The oxide-passivated nanocry…