Materials Literature
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The extracellular (interstitial) pH (pHe) of solid tumours is significantly more acidic compared to normal tissues. In-vitro, low pH reduces the uptake of weakly basic chemotherapeutic drugs and, hence, reduces their cytotoxicity. This phenomenon has been postulated to contribute to a 'physiological' resistance to wea…
We here present a versatile process for the preparation of maghemite/polyaniline (γ-Fe 2 O 3 /PAn) nanocomposite films with macroscopic processibility, electrical conductivity, and magnetic susceptibility. The γ-Fe 2 O 3 nanoparticles are coated and the PAn chains are doped by anionic surfactants of ω -methoxypoly(eth…
There are numerous operational problems with the technology of oil-filled transformers including their considerable mass and associated civil engineering. In addition, blast walls, acoustic baffles or sufficient space are required to protect surrounding buildings in an urban environment. In an attempt to answer these…
Time-resolved polarized Fourier transform infrared (FTIR) spectroscopy on thin microtomized sections of single-crystal ferroelectric liquid crystalline elastomers (SC-FLCE) is employed to analyze its structure and mobility in response to an external electric field. Due to its specificity, FTIR spectroscopy enables to…
The presence of surface-active compounds does not influence the settling time of a partially miscible liquid mixture as it phase separates. On the other hand, when the same mixture is agitated isothermally while in its two-phase state, its settling time greatly increases if surfactants are added. This phenomenon is mo…
Single-component polymeric precursors to SiC/Si 3 N 4 /C/BN and Si 3 N 4 /BN ceramic nanocomposites were synthesized via hydroboration and dehydrocoupling of vinyl-containing cyclotrisilazanes. The polymer-to-ceramic conversion process was investigated by 13 C, 29 Si, and 11 B solid-state magic-angle spinning (MAS) NM…
Mica powders with ultrahigh specific surface areas (ca. 100 m 2 /g) were treated with aqueous solutions of peroxide radical initiators bearing a single cationic group to exchange the mica surface ions with initiator cations. The stability of the initiators, the adsorption isotherms on the mica, and the adsorption equi…
The interdiffusion dynamics of a polymer interface towards its equilibrium profile is studied using a dynamical mean field method, in which the nonequilibrium chemical potentials are evaluated numerically using the full polymer mean field free energy. Our results demonstrated that the interfacial width grows as t 1/4…
The crystallization of nylons 6, 10, 6,12, and 4,6 was monitored in situ by X-ray diffraction from the melt. Nylons 6,10 and 6,12 were found to crystallize into the α-phase as indicated by the two-peak nature of the diffractogram. Nylon 4,6 crystallized with a single peak, which is characteristic of the γ-phase (hexag…
Wide-angle X-ray data point to a three-phase structure in isotropic and drawn specimens of a homogeneous poly(ethylene- co -octene) (7.3 mol % 1-octene). In addition to the amorphous halo, the unoriented polymer exhibits Bragg reflections characteristic of the orthorhombic crystalline phase and an additional reflectio…
The dielectric properties of layer perovskites in the Dion−Jacobson (KCa 2 Nb 3 O 10, HCa 2 Nb 3 O 10, CsPb 2 Nb 3 O 10, HPb 2 Nb 3 O 10, KCa 2 NaNb 4 O 13, KLa 2 NbTi 2 O 10 ) and Ruddlesden−Poppper (K 2 La 2 Ti 3 O 10 ) series, and of related lamellar oxides (KTiNbO 5, HTiNbO 5 ) were measured. Most of these compoun…
A new family of mesoporous silica molecular sieves with micelle-templated structures (MTS) has been synthesized using nonionic ethoxylated sorbitan esters, namely, Tween-20, -40, -60, or -80, as structure-directing agents. These MTS materials possess a wormhole-like framework typical of MSU- X mesostructures, with int…
A series of hydroxy-containing polyimides, containing pendent hydroxyl groups ortho to the heterocyclic imide nitrogen, were prepared via the solution condensation of aromatic dianhydrides with bisaminophenols. The polyimides were found to undergo thermal conversion to polybenzoxazoles upon heating between 350 and 500…
Repulsive and attractive forces are both possible between a superconducting sample and a permanent magnet, and they can give place to magnetic levitation or free-suspension phenomena, respectively. We show experiments to quantify this magnetic interaction which represents a promising field regarding to short-term tech…
Thin films were grown on amine-primed Si and glass substrates by sequential adsorption reactions of polyallylamine hydrochloride (PAH) and anionic colloids derived from HTiNbO 5 and HCa 2 Nb 3 O 10 . The acid−base chemistry of polycation/polyanion adsorption was studied in detail for PAH/HTiNbO 5 . The p K a of PAH, d…
We obtain an analytical solution of a one-dimensional sandpile problem in a thick flow regime, when it can be formulated in terms of linear equations. It is shown that a space periodicity takes place during the sandpile evolution even for a sandpile of only one type of particles. Similar periodicity was observed previ…
We examined what determines the designability of 2-letter codes (H and P) lattice proteins from three points of view. First, whether the native structure is searched within all possible structures or within maximally compact structures. Second, whether the structure of the used lattice is bipartite or not. Third, the…
2,2-Dibutyl-2-stanna-1,3-dioxepane (DSDOP) was polycondensed at 80 °C in bulk with succinyl chloride, adipoyl chloride, suberoyl chloride, sebacoyl chloride, and 1,12-dodecanedioyl chloride. In the case of adipoyl chloride the stoichiometry was varied and the temperature in the case of sebacoyl chloride. With a slight…
A unified interpretation is presented for high-temperature (ca. 423 K) unit-cell enlargement of MCM-41 synthesized in the presence of cetyltrimethylammonium (CTMA + ) surfactants without auxiliary organics. Such processes during postsynthesis hydrothermal treatments and direct syntheses were reported by several resear…
The decay of a crystalline cone below the roughening transition is studied. We consider local mass transport through surface diffusion, focusing on the two cases of diffusion limited and attachment-detachment limited step kinetics. In both cases, we describe the decay kinetics in terms of step flow models. Numerical s…