Materials Literature
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A model of relaxor ferroelectrics based on the interacting polar clusters picture has been formulated. The electric dipole moment of a nanosized polar domain is allowed a large number of discrete orientations and its length is assumed to fluctuate in a broad interval. Introducing a set of quasicontinuous order paramet…
The radiative lifetime, ${\ensuremath{\tau}}_{R},$ of the ${}^{5}{D}_{0}$ metastable excited state of ${\mathrm{Eu}}^{3+}$ ions in nanocrystalline monoclinic ${\mathrm{Y}}_{2}{\mathrm{O}}_{3}$ samples is about four times longer than that in the micron size powder of the same material. The ${\mathrm{Eu}}^{3+}$ radiativ…
Electronic structure calculations of $\ensuremath{\beta}\ensuremath{-}{\mathrm{BaB}}_{2}{\mathrm{O}}_{4}$ from first principles are performed based on a plane-wave pseudopotential method, and the linear optical properties are then obtained. The static second-harmonic generation (SHG) coefficients are calculated at the…
Femtosecond (fs) broad-band transient absorption (TA) is used to study the intraband relaxation and depopulation dynamics of electron and hole quantized states in CdSe nanocrystals (NC's) with a range of surface properties. Instead of the drastic reduction in the energy relaxation rate expected due to a ``phonon bottl…
A fully sealed field-emission display 4.5 in. in size has been fabricated using single-wall carbon nanotube (CNT)-organic binders. The fabricated displays were fully scalable at low temperature, below 415 °C, and CNTs were vertically aligned using paste squeeze and surface rubbing techniques. The turn-on fields of 1 V…
Aluminosilicate zeolites such as UTD-1 (structure shown) belong to a family of nanoporous inorganic materials that find utility in catalysis, separation, and ion exchange. During the last decade, the rate of discovery of new open-framework materials based, for example, on phosphates, sulfides, halides, nitrides, and c…
Abstract Numerical and experimental studies were performed to analyze a planar flow melt spinning process (PFMS) with a focus on the optimal nozzle design. Three-dimensional computational fluid dynamics (CFD) modeling using FIDAP was carried out to analyze the flow distribution in various nozzle shapes including recta…
Abstract In this paper, the non-linear dynamics of a new Shape Memory Alloy (SMA) actuator that possesses impressive payload lifting capabilities are presented. This actuator consists of 48 SMA wires mechanically bundled in parallel forming one powerful muscle. It was designed to lift up to 100 lbs., which is approxim…
Abstract Reactive melt infiltration is viewed as a promising means of achieving near-net shape manufacturing with quick processing time and at low cost. Since the reactants and products are, in general, of varying density, overall conservation of mass dictates that there is a force related to chemical conversion which…
Improvement of processability of Poly(ε-caprolactone) (PCL) was achieved by introduction of a branch structure using gamma-irradiation from a 60Co source. Irradiated PCL has higher molecular weight by producting a branch structure. Hence, the irradiation at a lower dose, such as 3 Mrad, leads to a higher melt viscosit…
Through differential scanning calorimetry, isothermal crystallization from the melt of polytetrafluoroethylene (PTFE) has been investigated. PTFE was regarded as one of the polymers for which crystallization is so rapid that the samples crystallize during the cooling from the melt to the selected crystallization tempe…
Crystallization and melting behaviors of poly(p-phenylene sulfide) (PPS) in blends with poly(ether sulfone) (PES) prepared by melt-mixing were investigated by differential scanning calorimetry (DSC). The blends showed two glass transition temperatures corresponding to PPS- and PES-rich phases, which increased with inc…
In this article, we describe the synthesis of polypeptides onto the whole specific surface of poly(ethylene terephthalate) particle track membranes. In this case, initial functionalization is necessary. It had been done by an optimized surface oxidation in accordance with the method of Marchant-Brynaert, J.; Deldime,…
Effects of corona treatment and aging on commercially produced corona discharged polypropylene (PP) films were followed via surface sensitive roughness analysis by atomic force microscopy (AFM), water contact angle (WCA), and X-ray photoelectron spectroscopic (XPS) measurements. Roughness analysis by AFM gave similar…
The physical aging of bisphenol A polycarbonate was studied using the differential scanning calorimetry technique. Cowie and Ferguson's model and Williams-Watts function were used to analyze the data. It is confirmed that the relation ΔH∞(Ta) = ΔCp(Tg − Ta), where ΔH∞(Ta) is the value of the aging enthalpy for t = ∞,…
We explore a new class of computationally feasible approximations of the two-body density matrix as a finite sum of tensor products of single-particle operators. Physical symmetries then uniquely determine the two-body matrix in terms of the one-body matrix. Representing dynamical correlation alone as a single tensor…
Interparticle interaction and structure of glycogen from a shell fish (mussels) were studied in water and 0.5 N NaOH by static and dynamic light scattering and viscometry. A concentration regime up to 30% w/v was covered. Beyond the overlap concentration a large-scale clustering was observed which was interpreted as a…
The [P 2 W 18 M 6 S 6 O 74 (H 2 O) 6 ] 12 - anions, M = Mo, W, were obtained through the stereospecific addition of the dithiocation [M 2 O 2 S 2 ] 2+ to the trivacant A-α-[PW 9 O 34 ] 9 - . K 12 [P 2 W 18 Mo 6 S 6 O 74 (H 2 O) 6 ]·26H 2 O has been isolated as crystals and has been characterized by X-ray diffraction (…
In this paper we describe an experimental procedure that can be used to study the photoreduction of metal ions on the surfaces of individual TiO 2 particles. The submicrometer-sized particles are isolated on porous membranes, characterized by atomic force microscopy (AFM), removed from the microscope, exposed to AgNO…
An azocarbazole-based polyimide was synthesized from an azocarbazole diamine monomer and 4,4‘-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) by a two-step polycondensation reaction. Birefringence experiments have been performed on the pure polyimide and on the polyimide mixed with small azo chromophores. Becaus…