Materials Literature
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There is great interest in the investigation of heterodimers formed by metalloporphyrins and metallophthalocyanines grafted with oppositely charged substituents, since these systems are models of the photosynthetic special pair and promising unidirectional electron transfer molecular devices. In the present study new…
Abstract Light‐induced spin‐polarized transient EPR spectra are reported for several water‐soluble copper porphyrins. The spectra are assigned to the doublet ground state, with emissive spin polarization resulting from photoexcitation and subsequent electronic relaxation. In contrast to other systems for which polariz…
The crystal structure of CaZr(PO 4 ) 2 was determined from conventional X-ray powder diffraction data using direct methods, and it was further refined by the Rietveld method. The structure was orthorhombic (space group P 2 1 2 1 2 1 , Z =4) with a =1.448 76(4), b =0.672 13(1), c =0.623 47(2) nm, and V =0.607 10(3) nm…
The interactions of dissociated lattice dislocations with a near-Σ = 3 grain boundary (GB) in copper have been investigated by transmission electron microscopy using the weak-beam technique combined with bright-field image matching. From our observations, Shockley partials are required to recombine when entering the G…
Molecular nonlinear optics describes the nonlinear optical properties of materials at the molecular level. At this most fundamental level, the nonlinear response can be described in terms of molecular parameters, such as number of polarizable electrons, non-centrosymmetric substitution by electron-donor or electron-ac…
We report the direct observation of electromigration and induced stress in the Cu nanowire. During the electromigration, the decrease in pulling stress in the nanowire is observed with the modification of the nanowire. When the nanowire reaches the stable state, the single crystal lattice of Cu appears in the nanowire…
Strong and fragile glass relaxation behaviours are obtained simply changing the constraints of the kinetically constrained Ising chain from symmetric to purely asymmetric. We study the out-of-equilibrium dynamics of these two models focusing on the Kovacs effect and the fluctuation–dissipation (FD) relations. The Kova…
Enzyme washing is commonly used as a wet process technique to improve textile handle, appearance, and other surface characteristics of cottons in the industry. In this research, we have studied the effects of cellulase treatment on tensile strength, flex abrasion resistance, and handle of cotton fabric crosslinked by…
TTF produces two completely different phenomena with the different isomers of chloranil; with the para isomer it produces an insulating, alternating stack, ambient temperature neutral solid. While with the ortho isomer, it produces a more interesting system consisting of interconvertible conducting ionic and covalent…
Abstract Expressions for the degree of randomness, B, and for the number- and weight-average block lengths of condensation copolymers containing both symmetrical (AA + BB) and unsymmetrical (AB) monomer units are established through an approach based on functional group probabilities. Several parameters introduced in…
Abstract The crystal structure of CaSiO 3 -walstromite has been solved and refined by a data set collected in situ from an inclusion in a diamond single crystal (1135 observed reflections, Mo K α , Nonius CAD4, R = 3.46). The crystal structure is almost identical to that of walstromite (Ca 2 BaSi 3 O 9 ). The replacem…
X-ray powder diffraction data, high resolution electron microscopy observation and refined unit cell parameters for δ-Al 2 O 3 prepared from γ-Al 2 O 3 are reported here. The new lattice parameters were a =7.9631(7) and c =23.3975(23) Å with space group P4 1 2 1 2 (No. 92). The new data provide evidence for the simple…
We obtained the molecular weight and long chain branching distribution for polyolefins made with a combination of two single-site metallocene catalysts in a CSTR. Long chain branches are assumed to be formed by the incorporation of chains formed with a double bond end (macromers) at the catalyst sites. In the case whe…
Abstract Acrylic process aids have been widely used for decades in the production of both rigid and flexible PVC materials. Their advantages are well‐known and are briefly reviewed in this paper. Excessive use of process aids or selection of the wrong molecular weights may, however, lead to undesirable behavior ultima…
Studies on the dissolution of stressed crystals have shown that stress corrosion can lead to roughening of interfaces. The corrosion pattern develops due to gradients in elastic energy along a free crystal surface with an initial roughness. Dissolution will cause further increase in elastic energy, which in turn will…
The types of damage to sample surfaces that can occur during x-ray or electron irradiation used during Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS) are summarized. The material and instrumental dependence of the rate and nature of damage formation or sample degradation are highlighted.…
Abstract This paper describes a method for evaluating the kinetic constants in a rate expression for catalytic combustion applications using experimental light‐off curves. The method uses a transient one‐dimensional single channel monolith finite element reactor model to simulate reactor performance. The heat and mass…
Abstract Alternating poly(amide urea)s from ε-caprolactam, diamines H 2 N-(CH 2 ) x - NH 2 (x = 2 - 4), and diphenyl carbonate were prepared in two steps. The microstructure of the poly(amide urea)s, as determined by means of 1 H NMR spectroscopy, reveals a strictly alternating sequence of the building blocks. The mol…
The role of KOH in the one-stage KOH-activation of rice straws was studied using FTIR, XPS, TGA, and DTG techniques. It was found that at the impregnation, KOH extracts to some extent the lignin component from rice straw and reacts with hydroxyl groups. On heat-treatment, the impregnated KOH facilitates intermolecular…
Abstract The type B structure of the single rare earth element disilicates has been revised using room temperature and pressure single-crystal X-ray diffraction measurements on Gd 2 Si 2 O 7 , Tb 2 Si 2 O 7 and Ho 2 Si 2 O 7 synthesized at 2–2.5 GPa, 1400–1500 °C in a piston-cylinder apparatus and Dy 2 Si 2 O 7 synthe…