Materials Literature
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Diffraction gratings with feature sizes comparable to the wavelength are analyzed with a finite-difference time-domain method, which is a unique approach to electromagnetic problems in the time domain. The diffraction efficiencies obtained are in good agreement with other commonly used numerical methods in the frequen…
Self-assembled metal chalcogenide open-framework materials such as that shown in the Figure—a projection on the [100] plane of the structure of a microporous layered tin(IV) sulfide (DABCOH)2Sn3S7 1, where DABCOH denotes singly protonated 1,8-diazabicyclooctane—are of interest for chemical sensing applications. A “ver…
Properties such as chemical and structural stability, thermal expansion and thermal conductivity are investigated, with the purpose of better characterizing the behaviour of Czochralski grown GdCOB [Ca4GdO(BO3)3], oxoborate single crystals, to be used in optical devices.
Aluminium alkoxide moieties are grafted onto purely siliceous mesoporous MCM-41 via siloxide linkages, producing materials which reveal enhanced catalytic activity in the MPV reduction of cyclic ketones; nitrogen physisorption and 27Al MAS NMR spectroscopy are applied to characterise the catalytically active hybrid sy…
2,2′-Bipyridines are known to coordinate to a wide variety of metal centres. In this paper, liquid-crystalline two-chained (dicatenar), four-chained (tetracatenar) and six-chained (hexacatenar) bipyridines are synthesised and their mesomorphism is described. For the tetracatenar bipyridines, a full homologous series,…
An account is given of the research that has been carried out on mechanical alloying/milling (MA/MM) during the past 25 years. Mechanical alloying, a high energy ball milling process, has established itself as a viable solid state processing route for the synthesis of a variety of equilibrium and non-equilibrium phase…
Cobalt(ii)–iron(iii) mixed hydroxides with hydrotalcite-like structure have been synthesized. Depending on the experimental conditions during synthesis, CoII becomes partially oxidized to CoIII . The solids have been characterized by X-ray diffraction, FTIR spectroscopy, temperature-programmed reduction and nitrogen a…
Secondary electron (SE) imaging of semiconductors reveals contrast between n- and p-type areas that can serve as the basis for a two-dimensional dopant profiling technique. In this article, recent experiments that address sensitivity, spatial resolution, calibration methodology, p/n junction effects, and sample prepar…
Nano-sized copper(i) oxide particles dispersed in nylon 11 thin films have been prepared by a thermal relaxation technique. The obtained composite films were characterized by XRD, HRTEM, XPS, AES and UV-VIS absorption spectroscopy. Upon heat treatment under air, metallic copper initially deposited on the nylon 11 surf…
Cyclodextrins are cyclic oligosaccharides. These molecules are able to form inclusion complexes with a large number of organic molecules. The properties of cyclodextrins enable them to be used in a variety of different textile applications. Cyclodextrins may act as auxiliaries in washing and dyeing processes, and they…
Zirconium oxide is active for photoreduction of gaseous carbon dioxide to carbon monoxide with hydrogen. A stable surface species arises under the photoreduction of CO2 on zirconium oxide and is identified as surface formate by IR spectroscopy. Adsorbed CO2 is converted to formate by photoreaction with hydrogen. The s…
Electrochromic (EC) behaviours of nickel oxide (NiOx) thin films, grown by chemical process in a nickel ammine complex solution [Ni(NH3)x2+] after electrolysis of this solution (EL–C method), were investigated using various alkaline electrolyte solutions; potassium borate buffer (pH 12), KOH (pH 12.9), (CH3)4NOH and (…
Atomic stresses were calculated for carbon nanotubes under strain conditions. Graphitic tubules with radii ranging from approximately 2 to 11Åand two different tubule structures with varying atomic orientations were included in the calculations. Elongations and contractions were applied in the axial direction and atom…
The protonation constants (K iH) of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (H4dota) were redetermined at 25 °C in 0.1 M NMe4Cl. The log Ki H values (i = 1–5) are 12.6, 9.70, 4.50, 4.14 and 2.32, respectively. The stability constants of [Ce(dota)]– and [Yb(dota)]– were determined by pH-potentiometry a…
Polymeric blends of silk fibroin (SF) and S-carboxymethyl kerateine (SCMK) were prepared by the solvent casting method to study the effect of surface properties on the antithrombogenicity. The films of SF/SCMK showed better antithrombogenic properties than SF or SCMK alone. Among them, the film containing 50 wt% SCMK…
New methodology was developed for the selective synthesis of regiochemically defined porphyrazines of the form M[pz(A 2;B 2 )] (shown in Chart 1) where A and B represent peripheral functionalization attached to the β-positions of the pyrroles. Specifically, phthalonitriles or derivatives thereof with sterically bulky…
A number of dendrimers based on polyhedral silsesquioxane cores have been synthesised and characterised. The new molecules are prepared by repetitive hydrosilation/alkenylation reactions, which provide a facile and high yield route to dendrimers with a high density of branch ends per generation. Judicious choice of hy…
The electromagnetic microwave absorption properties of Barium M-type ferrite, in which Fe3+ was substituted by (Ti0.5Mn0.5)3+, were investigated in the GHz frequency range. The anisotropy field (HA) of Barium M-type ferrite can be changed by varying the Ti0.5Mn0.5 content, which enables the natural resonance frequency…
Exposure of the polymeric solid [CuI(4-pic)]∞ to either liquid or vapor toluene leads to disappearance of this material’s characteristic room temperature blue emission (λmax 437 nm) and the appearance of the yellow emission (λmax 580 nm) indicative of the [CuI(4-pic)]4 tetramer; the process is reversed when the latter…
Constant voltage anodizing of binary Mg‐Al alloys containing 2, 5, 8, and 12% of aluminum was studied. Anodizing was conducted in a bath containing 3 M KOH + 0.6 M KF + 0.21 M with additions of 0.013, 0.064, 0.13, and 0.4 M of . A thin amorphous film was formed during the first stage of anodizing. Prolonged anodizing…