Materials Literature
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A series of monolithic poly[methyl methacrylate- co -3-(trimethoxysilyl)propyl methacrylate]−silica hybrid materials have been prepared via the sol−gel reactions. The fracture surfaces of the materials were systematically examined with atomic force microscopy (AFM) as a function of the silica content from ∼23 to 100 v…
New soluble polyimides were prepared from a series of diamines and a tetracarboxylic dianhydride with a benzhydrol unit, 3,3‘,4,4‘-benzhydrol tetracarboxylic dianhydride (BHTDA), by one-step method polymerization. The diamines containing flexible units, bulky substituents, and/or noncoplanar conformation unit were pre…
Theoretical considerations of the molecular hyperpolarizabilities (β) of donor−acceptor substituted aromatic molecules show that the transfer of a proton from the electron-donor group of an acid to the electron acceptor group of a base could increase β for both resulting ionic species relative to the corresponding neu…
A series of alkyl-substituted and unsubstituted poly(3,4-alkylenedioxythiophene)s were synthesized electrochemically using 3,4-alkylenedioxythiophene derivative monomers where either the size of the alkylenedioxy ring or the nature of the pendent group was varied. The specific systems studied include 3,4-ethylenedioxy…
This four-volume reference aims to provide information on the basic principles of both low- and high-molecular weight materials, as well as the synthesis, characterization, modification, and applications (such as in computer displays or as structural materials) of all types of liquid crystals. Volume 1, for example, d…
Hydroxypropyl methylcellulose acetate succinate (HPMCAS) is a new enteric coating material developed by Shin-Etsu Chemical Co., and is marketed under the trade name Shin-Etsu (AQOAT® [49]. It is available in three grades: AS-L(F or G), AS-M(F or G), and AS-H(F or G), corresponding to an average succinyl to acetyl subs…
X-ray photoelectron spectroscopy, XPS, was used for the characterization of electrically conducting polymeric materials. In the spectrum of polypyrrole, PPy, the Nls region exhibits two peaks, at 402.0 and 399.8 eV, corresponding to -N+ - and -N-moieties, respectively. The intensity of the N+ peak decreases as the mat…
By a combination of Q-band pulsed ENDOR (electron nuclear double resonance) and X-band ESEEM (electron stimulated echo envelope modulation) techniques, we have determined the hyperfine tensors for ethylene (C1) and cyano (C2) carbons and N, of [Ni(mnt)(2)](-), along with the quadrupole tensor for nitrogen. These measu…
The changes in chemical states and composition of the surface region of a Ag 2 CO 3 powder at various stages during thermal decomposition have been examined using X-ray photoelectron spectroscopy (XPS) and ion scattering spectroscopy (ISS). The near-surface region of the as-received powder consists primarily of Ag 2 C…
The collision of two equi-sized drops immersed in an immiscible liquid phase undergoing a shear flow in a parallel plate apparatus has been investigated over a range of capillary numbers. The drops were observed along the vorticity direction of shear flow by video enhanced contrast optical microscopy. Images of the co…
An investigation is made into the dynamics involved in the movement of the contact line when a single liquid with an interface moves into a vacuum over a smooth solid surface. In order to remove the stress singularity at the contact line, it is postulated that slip between the liquid and the solid or some other mechan…
We consider a superconducting film with Magnetic Dots Array (MDA) placed on it. Magnetic moments of these dots are supposed to be normal to the film and strong enough to create vortices in the superconducting film. Magnetic interaction between dots is negligible. Below the superconducting transition temperature of the…
We present a thermodynamics argument against a strictly linear temperature dependence of the magnetic penetration depth, which applies to superconductors with arbitrary pairing symmetry at low temperatures.
We study hysteresis for a two-dimensional, spin-1/2, nearest-neighbor, kinetic Ising ferromagnet in an oscillating field, using Monte Carlo simulations and analytical theory. Attention is focused on small systems and weak field amplitudes at a temperature below $T_{c}$. For these restricted parameters, the magnetizati…
The bonding between two M(dmit)(2) monomers (M = Ni, Pd, Pt) in the stacks that are characteristic for the crystal structure of these compounds has been analyzed, using decomposition of the interaction energy in steric repulsion, electron pair bond formation, and donor-acceptor interactions. Atom over atom (eclipsed)…
This work has synthesized new diamantane-based polyimides by reacting 1,6-bis(4-aminophenyl)diamantane ( 5 ) with various aromatic tetracarboxylic dianhydrides. Dynamic mechanical analysis (DMA) reveals that diamantane-based polyimides have three relaxations on the temperature scale between 0 and 500 °C. The low-tempe…
Optical absorption and extended X-ray absorption fine structure (EXAFS) spectra were measured on series of ZrF 4 −BaF 2 −LaF 3, ZrF 4 −BaF 2 −MF−LaF 3 (M; Li, Na, K, Rb, or Cs) and AlF 3 −BaF 2 −CaF 2 −YF 3 glasses doped with Ni 2+ . The optical absorption spectra show that Ni 2+ ions in all the glasses exist in octah…
The influence of the Ni deposition mode on the dispersion of Ni 2+ precursors was investigated in the preparation of Ni/SiO 2 catalysts. The coordination sphere of Ni complexes was mainly studied by XAFS spectroscopy in the initial step (dried samples) and after a vacuum activating treatment at 700 °C. Four modes of d…
The oxygenase domain (amino acids 1-498) of inducible nitric oxide synthase (iNOSox) is a hemeprotein that binds L-arginine (L-Arg) and tetrahydrobiopterin (H4B). During NO synthesis, the heme iron must bind and activate O2, but it also binds self-generated No to form an inactive complex. To better understand how L-Ar…
Freshly vacuum-evaporated, neat amorphous MoO 3 thin films exhibit only UV photochromism. Visible-light photochromism is induced in these films when they are cathodically polarized for a short duration in a nonaqueous electrolyte. The efficiencies of the UV and visible-light photochromism of the MoO 3 thin films incre…