Materials Literature
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Combining the augmented space representation for phonons with a generalized version of Yonezawa-Matsubara diagrammatic technique, we have set up a formalism to seperate the coherent and incoherent part of the total intensity of thermal neutron scattering from disordered alloys. This is done exacly without taking any r…
Dots in cells: Recent advances in the use of functionalized semiconductor quantum dots in bioimaging, from cancer studies to blood-flow monitoring, are described. The image shows a mouse fibroplast labeled with two different sizes (and therefore two different colors) of CdSe/ZnS quantum dots.
The transport properties of high-performance thin-film transistors (TFT) made with a regio-regular poly(thiophene) semiconductor (PQT-12) are reported. The room-temperature field-effect mobility of the devices varied between 0.004 cm2/V s and 0.1 cm2/V s and was controlled through thermal processing of the material, w…
We report our detailed calculation of the infrared spectra of GaAs and GaP from first principles, and similar ongoing efforts for diamond-type spectra, which have recently been calculated.
Studies of the kinetics of the bias-stress effect are reported for PQT-12 polymer thin film transistors. We associate the bias-stress effect with bipolaron formation, based on the observation that the stressing rate is proportional to the square of the hole concentration. The bipolaron formation rate is measured as a…
On a Si(111) vicinal face near the structural transition temperature, the $1 \times 1$ structure and the $7 \times 7$ structure coexist in a terrace: the $1 \times 1$ structure is in the lower side of the step edge and the $7 \times 7$ structure in the upper side. The diffusion coefficient of adatoms is different in t…
We study the half-breathing phonon in the three-band model of a high temperature superconductor, allowing for vibrations of atoms and resulting changes of hopping parameters. Two different approaches are compared. From the three-band model a t-J model with phonons can be derived, and phonon properties can be calculate…
electromagnetic field distributions are found for frequencies slightly under one hundred giga Hertz, using a left handed substrate in a microstrip guided wave structure
We report the synthesis of colloidal Mn2+-doped ZnO (Mn2+:ZnO) quantum dots and the preparation of room-temperature ferromagnetic nanocrystalline thin films. Mn2+:ZnO nanocrystals were prepared by a hydrolysis and condensation reaction in DMSO under atmospheric conditions. Synthesis was monitored by electronic absorpt…
Inhomogeneously doped thermoelectric nanomaterials with a delta-function electronic density of states can operate with Carnot efficiency in the absence of phonon heat leaks. Here we self-consistently calculate the efficiency and power from open-circuit to short-circuit of a simple model of a thermoelectric nanomateria…
The native extracellular matrix (ECM) of elastic tissues is strong and flexible and supports cell adhesion and enzymatic matrix remodeling. In an attempt to convey these ECM properties to a synthetic scaffold appropriate for soft tissue engineering applications, a biodegradable, elastomeric poly(ester urethane)urea (P…
New interesting α-SiAlON:Eu-based yellow oxynitride phosphors with the formula (Ca x Eu y )Si 12 - 2 x - 3 y Al 2 x +3 y O y N 16 - y ( x = 0.2−2.2, y = 0−0.25) have been prepared, and the effects of the activator concentration and the overall composition of the host lattice on optical properties have been investigate…
The largest known Dy–Mn complex is [DyIII6MnIII4MnIV2(H2shi)4(Hshi)2(shi)10] (H3shi is salicylhydroxamic acid; see stereopicture). The Dy ions are arranged in a nearly planar hexagonal ring and are capped on opposite sides by a MnIII2MnIV trimer. This mixed-metal topology provides a new structure class for the examina…
A review of electrochromic (EC) polymers and their applications in absorption/transmission, reflective, and patterned electrochromic devices (ECDs) is presented. Fundamental properties of EC materials such as optical contrast, coloration efficiency, switching speed, and stability are described along with the commonly…
A versatile self-assembly process for preparing nanoscale “sandwich” layer arrays(see Figure) by incorporating bimetal solid solutions into a biological system is reported. Collagen was used as the biological scaffold, and also to control the growth of various metal nanocrystals in an exact arrangement, using two unif…
The influence of the charge transfer between metal and oxygen atoms on the EELS integrated cross sections has been studied experimentally and theoretically in titanium and manganese oxides of different valence. It is demonstrated that the behavior of the metal ${L}_{2,3}$ integrated cross section can be connected with…
Abstract A novel fluorinated aromatic dianhydride, 4,4′‐[2,2,2‐trifluoro‐1‐(3‐trifluoromethyl‐phenyl)ethylidene]diphthalic anhydride (TFDA) was synthesized by coupling of 3′‐trifluoromethyl‐2,2,2‐trifluoroacetophenone with o ‐xylene under the catalysis of trifluoromethanesulfonic acid, followed by oxidation of KMnO 4…
Many novel applications of silver become possible if silver nanotubes can be produced reliably and easily. A simple, template-assisted procedure is reported here. The Figure shows a scanning electron microscopy image of one of the silver nanotubes, which was broken by ultrasonic vibration, demonstrating that the nanos…
We present experimental results on the dynamics of wormlike micellar filaments surrounded by an immiscible viscous bulk fluid. For certain concentrations, these filaments develop a beads-on-string structure previously observed only in polymer jets and filaments surrounded by air. By taking advantage of the longer time…
In Methanothermobacter thermautotrophicus, oxaloacetate synthesis is a major and essential CO(2)-fixation reaction. This methanogenic archaeon possesses two oxaloacetate-synthesizing enzymes, pyruvate carboxylase and phosphoenolpyruvate carboxylase. The phosphoenolpyruvate carboxylase from this organism was purified t…