Materials Literature
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Silver nanocrystals have been grown on Xe buffer layers at 50 K. These 3D nanocrystals are delivered to $\mathrm{Si}(111)\ensuremath{-}(7\ifmmode\times\else\texttimes\fi{}7)$ surfaces when the Xe layer is desorbed, but the density observed on the surface depends strongly on the buffer layer thickness. This dependence…
A new coordination mode for the porphyrin ligand is found in [B2O2(BCl3)2(tpClpp)] (tpClpp=dianion of 5,10,15,20-tetra-p-chlorophenylporphyrin; the p-chlorophenyl groups are omitted for clarity in the picture shown on the right). This complex contains a four-membered B2O2 ring in the cavity of the ligand. The two boro…
Der bislang größte anorganische Cluster [(MoO3)176(H2O)80H32](2±2)− 1 (im Bild rechts sind die Mo-O-Polyeder gezeigt), der jetzt röntgenstrukturanalytisch charakterisiert wurde, weist neben einem Hohlraum mit einem Durchmesser von 2.3 nm bemerkenswerterweise die Stöchiometrie eines reduzierten, protonierten und hydrat…
Simply mixing solutions of the title compound 1 and tetrathiafulvene (TTF) in acetonitrile provides the charge-transfer complex 2. Here, 1 functions as a novel electron acceptor and is present in the complex as a radical anion. An electrical conductivity of up to 3 S cm−1 was determined for 2 with a two-point powder m…
We have investigated the formation of polymer walls for high polymer content liquid crystal (LC) formulations, using a patterned electric field to induce phase separation. The effect of this field on the phase separation temperature of a LC/monomer mixture is studied as a function of the photopolymerizable monomer con…
Deposition of individual single-wall carbon nanotubes over multiple (up to seven) Pt nanoelectrodes is realized. Two-probe and four-probe transport measurements between adjacent pairs of electrodes show similar but not identical single-electron Coulomb charging signatures at low temperatures. The observations indicate…
High-sensitivity femtosecond transient absorption is applied to directly measure the population-depopulation dynamics of the lowest ( $1S$) and the first excited ( $1P$) electron states in CdSe nanocrystals (NC's) of different radii with $1S$--- $1P$ energy separation up to 16 longitudinal optical phonon energies. Ins…
Copper(II)-containing nickel(II) hydroxide particles, i.e., α-Ni 1 - x Cu x (OH) 2 (0 < x ≤ 0.4), have been prepared by aging 0.5 mol dm - 3 urea, Ni(NO 3 ) 2, and Cu(NO 3 ) 2 solutions at 363 K. After 3 h, coprecipitation is almost complete. The formed solids, characterized by powder X-ray diffraction, scanning elect…
The electrical transport properties, such as direct current (dc) electrical conductivity (σ), dielectric constant (ε′), and dc current–time characteristics of unirradiated and γ-irradiated pure and NiCl2-doped PVA were studied in the temperature range of 26–155°C. Quantitative analysis was carried out to determine the…
The reaction between Ru(2)(O(2)CMe)(4)Cl and Hadmp (Hadmp = 2-amino-4,6-dimethylpyridine) under different conditions has been investigated. By conducting the reaction in a methanol solution at room temperature the product obtained was Ru(2)(admp)(O(2)CMe)(3)Cl (1). In a melt reaction at 65 degrees C the product isolat…
The reaction of [Fe(salen)](+) and {A(3)[Fe(CN)(6)]} (A = NEt(4), K), depending on the countercation A(+) and on the reaction solvent, led to [(NEt(4)){Fe(salen)}(2){Fe(CN)(6)}](n)(), 4, and [{Fe(salen)}(3){Fe(CN)(6)}(MeOH)(2)](n)().3nH(2)O, 5 [NEt(4) = tetraethylammonium cation, salen = N, N'-ethylenebis(salicylidene…
A mathematical model for solid-state polymerization of poly(ethylene terephthalate) was developed. The effects of temperature and chain entanglement on chain mobility were considered to estimate the rate constants of chemical reactions. The diffusivities of volatile byproducts could be determined using the free volume…
New types of ecologically friendly polymer flame-retardant systems were proposed for Nylon 6,6 and polypropylene [high temperature polymer–organic char former, poly(vinyl alcohol), and silicon–inorganic system]. These systems can act in condensed and gaseous phases. The cone calorimeter and LOI tests indicated the imp…
Starch-based polyurethane foams were synthesized by reacting a mixture of starch and polycaprolactone triol with an aliphatic diisocyanate, in the presence of water as blowing agent. Some foams were also prepared by adding a certain amount of polyethyleneglycol. The reaction kinetics is affected by the presence of sta…
An ion-exchangeable thin film which has the layered structure of K 4 Nb 6 O 17 was prepared from a suspension of fine particles of K 4 Nb 6 O 17 . The superfine particles which were obtained by wet grinding were coated onto a substrate, and they were calcined between 873 and 1073 K. Crystallization of the fine particl…
Nafion®/SiO2, Nafion®/[ORganically MOdified SILicate (ORMOSIL)] and Nafion®/dimethylsiloxane hybrids were created via in situ sol–gel reactions for tetraethoxysilane, diethoxydimethylsilane, and their mixtures. Differential scanning calorimetry studies showed a broad endotherm for unfilled Nafion®-H+ at Tα ≈ 215°C tha…
Crystallization of sodium acetate trihydrate from water affords hexagonal plates. When crystallized from cyclohexane, a solvent in which this salt is completely insoluble but in which it may be solubilized by macrocyclic crown polyethers, needle-shaped crystals are produced. This habit change is consistent with select…
The possibilities of ‘resistless’ microstructuring of As36·1S63·9 wafers by soft X-ray irradiation and wet alkaline etching have been investigated. Scanning electron microscopy is used to study the influence of the exposure and processing parameters on the depth and acuity of the patterned structures. Structures 1 μm…
Experimental film formation of a rubber-based negative photoresist by spin coating relative to that of a diazoquinone sensitized positive photoresist was investigated. The baked film produced with the negative photoresist is thinner than that produced with the positive photoresist in the first stage of the spinning in…
The low-temperature crystal structure and temperature dependence of lattice parameters and atomic mean-square displacements of thallium nitrite (${\mathrm{TlNO}}_{2})$ and cesium nitrite (${\mathrm{CsNO}}_{2})$ have been determined by neutron powder diffraction. Previously, based on specific heat and dielectric relaxa…