Materials Literature
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2,2-Dibutyl-2-stanna-1,3-dioxepane (DSDOP)-initiated copolymerizations of trimethylene carbonate (TMC) with β-D,L-butyrolactone (β-D,L-BL), δ-valerolactone (δ-VL), ε-caprolactone (ε-CL) or L-lactide (Lac) were performed in chlorobenzene at 80°C. When equimolar mixtures of TMC and a lactone were copolymerized, copolyes…
During blood coagulation, prothrombin (PT) is ultimately degraded to three fragments, thrombin, fragment 1 (F1) and fragment 2 (F2), which, collectively, contain all of the structural features of PT. One of these fragments, F1, is excreted in human urine and is the principal protein occluded into calcium oxalate (CaOx…
Polymer technology has shown good performance and has certain advantages over ceramic technology in insulators. However, it often comes with a potentially weak point, i.e., the interface between two solid insulators. In The Netherlands, a cascade of 150 kV termination breakdowns occurred several years ago. The present…
Electropolymerization of zinc-10-bipyridinium-octaethyl-porphyrinate by cyclic scanning between −0.6 and +1.6 V yields a zigzag configured polymer, which appears as swollen, vesicular bilayer on atomic force micrographs. The same procedure leads to micrometer-long wire-shaped linear polymers, if the 5,15-methine bridg…
The connection between the crystallographic phase problem and the feasible set approach is explored. It is argued that solving the crystallographic phase problem is formally equivalent to a feasible set problem using a statistical operator interpretable via a log-likelihood functional, projection onto the non-convex s…
Poly(imide–silica) hybrid materials with covalent bonds were prepared by (3-aminopropyl)methyldiethoxysilane (APrMDEOS) terminated amic acid, water, and tetramethoxysilane (TMOS) via a sol–gel technique. Infrared (IR), 29Si and 13C CP/MAS nuclear magnetic resonance (NMR) spectroscopy, and thermogravimetric analysis (T…
Simultaneous piezoelectric microgravimetry and cyclic voltammetry (CV) at an electrochemical quartz microbalance have been used to monitor the growth of poly(neutral red) films on the gold and graphite electrodes during potential cycling between –0.7 V and 0.75 V (vs. SCE) in sodium phosphate buffer (pH 5.3) and NaNO3…
The dissolution rates of most primary and secondary minerals are promoted by the presence of proton‐ and complex‐forming ligands. Effects on the rates of dissolution of hornblende by naturally occurring organic acids at concentrations commonly encountered in soil solutions and surface waters was studied in a pH 4.0, 0…
ABSTRACT Average cholesterol reduction increased as β‐cyclodextrin concentration increased, regardless of other factors. The process was optimized using RSM. When β‐cyclodextrin addition was 10%, the effect of stirring speed was more noticeable than that of stirring time. When stirring speed was at 1,600 rpm, 94.2% of…
Poly(dimethylsiloxane) networks were prepared by tetrafunctionally end-linking hydroxyl-terminated chains with tetraethoxysilane (TEOS). Molecular composites were then prepared by in situ sol–gel reactions on additional TEOS swelled into the networks, resulting in the formation of reinforcing silica fillers within the…
After a brief introduction to discotic liquid crystals, we describe recent progress in elucidating the properties of the columnar phases as one-dimensional electrical conductors (or molecular wires), fast photoconductors, light emitting diodes and ferroelectrics, all of which have potentially important practical appli…
A series of $[{\mathrm{La}}_{2/3}{\mathrm{Ca}}_{1/3}{\mathrm{MnO}}_{3}(\ensuremath{\Lambda}/2)/{\mathrm{La}}_{1/3}{\mathrm{Ca}}_{2/3}{\mathrm{MnO}}_{3}(\ensuremath{\Lambda}/2){]}_{15}$ multilayers, with bilayer thicknesses $\ensuremath{\Lambda}$ between $2$ and 32 nm, has been prepared by pulsed laser deposition. The…
Herein we examine the origin of the high-temperature (350 K) behavior of a thermophilic mutant enzyme (labeled as 5-3H5; see Zhao and Arnold Prot. Eng. 1999, 12, 47−53) derived from subtilisin E by eight amino acid substitutions. Through the use of molecular dynamics (MD) simulations, we have provided molecular-level…
A method for accurate dimensional and angular measurements of microstructures analysed in the scanning electron microscope is described. The method considers central and parallel projections and involves (a) digital image acquisition of stereopaired images from the scanning electron microscope's photodisplay, (b) gene…
Epoxy-anhydride cure has been studied by differential scanning calorimetry under nonisothermal conditions. The isoconversional method of kinetic analysis yields a dependence of the effective activation energy on the extent of conversion (α) that increases from ≈ 20 to 70 kJ·mol–1 with increasing α. The occurrence of t…
A linear elastic solution is proposed for a circular disc in transition from a plate-like (pure bending) to a membrane-like behavior (pure stretching) under a central point load. The strain energy release rate for film delamination is found to be G = χ(Pw 0/πa 2) with χ a numerical constant varying from 1/2 for a plat…
Thin silica–titania films doped with different concentration of PbS quantum dots (PbS/oxide molar ratios ranging from 5% to 25%) were fabricated via a sol-gel route. The structural properties were studied by x-ray diffraction, high-resolution transmission electron microscopy, and Rutherford backscattering spectrometry…
A range of compositions and temperatures below the monotectic temperature exists where there are thermodynamic restrictions that prevent the equilibrium solid from forming directly from the undercooled homogeneous liquid. In this region, the solid can form only after liquid‐liquid phase separation has occurred. As sug…
We report on the microstructure and mechanical properties of diamond films grown using varying nitrogen additions to a plasma with a high-CH4 fraction of 15% (in hydrogen) and an operating pressure of 125 Torr. Films were grown at N2/CH4 ratios ranging from 0 to 0.30 by fixing the CH4 flow rate and changing only the N…
The influence of yttrium doping on the microstructure and microchemistry of hot‐pressed α‐alumina was investigated using a combination of electron microscopy techniques. The implications of microstructure and microchemistry on the improved creep behavior of the doped material are discussed. The samples doped only with…