Materials Literature
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The accurate control of a system that exhibits hysteresis requires a control strategy that incorporates some form of compensation for the hysteresis. One approach is to develop an accurate model P of the hysteresis and then use the inverse P<SUP>-1</SUP> as a compensator (inverse compensation). This paper focuses on t…
The photoluminescence behavior of dicyanoargentate(I) ions doped in KCl host crystals has been studied. Several ultraviolet and visible emission bands are observed in this system. Each emission band becomes dominant at a characteristic excitation wavelength; that is, the energy of the emission can be tuned by site-sel…
Novel Ru(II) and Ru(III) complexes having TPA (tris(2-pyridylmethyl)amine, L1) and 5-Me(3)-TPA (tris(5-methyl-2-pyridylmethyl)amine, L2) were prepared to establish their synthetic routes and to elucidate coordination geometry and interactions between tightly bound tripodal tetradentate ligands and Ru(II)/Ru(III) cente…
The secondary relaxations of a series of glassy copolymers based on poly(ethylene terephthalate) (PET) and poly(1,4-cyclohexylenedimethylene terephthalate) (PCT) involve cooperative motions of the cyclohexylene rings. The cooperativity gives rise to longer range motions which create significant volume fluctuations tha…
We present numerical simulations of avalanches and critical phenomena associated with hysteresis loops, modeled using the zero-temperature random-field Ising model. We study the transition between smooth hysteresis loops and loops with a sharp jump in the magnetization, as the disorder in our model is decreased. In a…
The thermal properties of silver are calculated within the quasi-harmonic approximation, by using phonon dispersions from density-functional perturbation theory, and the pseudopotential plane-wave method. The resulting free energy provides predictions for the temperature dependence of various quantities such as the eq…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationDirect Observation of Size-Dependent Optical Enhancement in Single Metal NanoparticlesSteven R. Emory, William E. Haskins, and Shuming NieView Author Information Department of Chemistry, Indiana University Bloomington, Indiana 47405 Cite this: J. Am. Chem. Soc. 1998, 120,…
Titania, zirconia, and alumina samples with periodic three-dimensional arrays of macropores were synthesized from the corresponding metal alkoxides, using latex spheres as templates. In a fast, single-step reaction, the monomeric alkoxide precursors permeate the array of bulk polystyrene spheres and condense in air at…
We investigate morphology evolution under melt blending of an immiscible mixture of two polymers, to which small amounts of a block copolymer are added as an emulsifier. We demonstrate the effect on blend morphology of an exothermic interaction between the major component, which constitutes the continuous matrix, and…
The Raman spectrum of dihydrofolate (H 2 folate) complexed with dihydrofolate reductase (DHFR) and NADP +, believed to be an accurate mimic of the productive DHFR/NADPH/H 2 folate complex involved in the reaction catalyzed by DHFR, contains bands associated with stretch motions of N5 C6 of bound substrate. However, th…
The mechanism of poly( p -phenylenebenzoxazole) formation from terephthalic acid (TA) and diaminodihydroxybenzene dihydrochloride (DADHB) in polyphosphoric acid (PPA) was studied. The solubility of TA in PPA with 86% P 2 O 5 content was determined to be 0.02% at 100 °C and 0.06% at 140 °C. Dissolved TA existed as thre…
The sequential reaction of (OEP)Os(CO) with NOPF 6 (in CH 2 Cl 2 ) followed by RMgX (in THF) gives variable isolated yields of the new (OEP)Os(NO)R (5−44%), (OEP)Os(R) 2 (1−10%), (OEP)Os(NO)X (14−19%), and [(OEP)Os(NO)] 2 (μ-O) (up to 24%) compounds, depending on the reaction conditions and the nature of R and X (OEP…
This paper reports a systematic experimental and theoretical study of the second-order nonlinear optical properties of multichromophoric molecules that range from dipolar symmetry to three-dimensional octupolar symmetry. The four possible conformers of tetranitrotetrapropoxycalix[4]arene ( cone, paco, 1,2-alt, 1,3-alt…
The degree of polymerization (DP n ) of poly( p -phenylene) (PPP) 3 with appendant third-generation, Fréchet-type dendrons was determined as 110 after a chemical modification. This DP n is extraordinarily high and shows that the mechanistically complex Suzuki polycondensation can thus be employed even in the case of s…
The effects of a metal ion-bound carboxylate group on the acidity of a water molecule bound to the same cation have been assessed by ab initio molecular orbital calculations. In the hexahydrate Mg[H 2 O] 6 2+ the free energy required to deprotonate one coordinated water molecule is only 40% of that required to deproto…
Forced Rayleigh scattering (FRS) and pulsed-field-gradient NMR have been used to measure the self-diffusion coefficient, D, of a poly(ethylene oxide)−poly(ethylethylene) diblock copolymer in the molten state. The copolymer contains 42% PEO by volume and has a total molecular weight of 4100 g/mol. Upon heating from roo…
Poly(vinyl alcohol)- (PVA) and Cu(OH) 2 −PVA-intercalated graphite oxide (GO) were prepared and characterized in detail. The I c values of PVA-intercalated GO varied widely in the range 1.32−2.24 nm. In the case of PVA-intercalated GO, a stepwise increase of the I c value of ∼0.5 nm was observed along with the increas…
Argon plasma treatment and subsequent atmospheric exposure have been used to incorporate new oxygen functionalities at the surface of polystyrene (PS) and polypropylene (PP). High-energy resolution X-ray photoelectron spectroscopy (XPS) has yielded molecular information regarding the site of modification in both polym…
In tetragonal zirconia, the cation is coordinated by two interpenetrating tetrahedra of oxygen ions, implying two different cation-oxygen bond lengths. Neutron powder diffraction was used to study tetragonal ZrO2–2 mol% Y2O3 incorporating various amounts of the different tetravalent ions Ge, Ti, Sn and Ce. Precise and…
This paper discusses the design and performance of a 256 X 256 bolometer-type uncooled infrared detector. First, model calculations are carried out to clarify the relations of the noise equivalent temperature difference (NETD) to the electrical properties of the bolometer material. The properties are mainly resistivit…