Materials Literature
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The effect of the overall crystallinity and the initial crystal morphology on the welding behavior of semicrystalline polymers was investigated by means of T-peel testing above and below the melting point using ultrahigh-molecular-weight polyethylene (UHMWPE) as a model polymer. Different crystal morphologies were gen…
Crystalline cyclic poly(oxyethylene)s with number-average molar masses ( M n ) of 4000, 6000, and 10000 g mol -1 were studied by wide-angle (WAXS) and small-angle (SAXS) X-ray scattering, high-frequency and low-frequency laser-Raman spectroscopy, and differential scanning calorimetry (DSC). The subcell of the crystall…
A pure silica MCM-41 preparation with high crystalline order perpendicular to the channels has been examined using small-angle neutron scattering and the contrast variation method in both the calcined and template-containing forms. This defines various structural features such as template and water distributions and c…
A layer-by-layer film could be fabricated on a substrate by the consecutive adsorption method based on the charge-transfer (CT) interaction between electron-donating carbazolyl groups and electron-accepting 3,5-dinitrobenzoyl groups in the side chains of two kinds of methacrylate polymers, poly[2-(9-carbazolyl)ethyl m…
A novel flavonoid diglycoside, 5,6,7,4'-tetrahydroxyflavonol 3-O-rutinoside (1), and a previously known compound, kaempferol 3-O-neohesperidoside (2), were isolated from an ethyl acetate extract of Daphniphyllum calycinum leaves that showed significant activity in a 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical as…
Amphiphilic hydrogen bond networks consisting of alkylated melamines and ammonium headgroup-appended cyanuric acids are stably dispersed in water as supramolecular membranes. Electron micrographs of these aqueous dispersions indicated the formation of supramolecular assemblies of mesoscopic dimension. Their aggregate…
Single-component monolayers of dendrimers and two-component monolayers consisting of dendrimers and n -alkanethiols immobilized on Au substrates are described. Single-component monolayers are prepared by exposing an Au substrate to ethanolic solutions of amine- or hydroxy-terminated polyamidoamine (PAMAM) dendrimers.…
The lifetime of image states, which represent a key quantity to probe the coupling of surface electronic states with the solid substrate, have been recently determined for quantum numbers $n\le 6$ on Cu(100) by using time-resolved two-photon photoemission in combination with the coherent excitation of several states (…
The electronic response of a composite consisting of aligned metallic cylinders in vacuum is investigated, on the basis of photonic band structure calculations. The effective long-wavelength dielectric response function is computed, as a function of the filling fraction. A spectral representation of the effective resp…
Heat capacity measurements on the prototypical three-dimensional random-field Ising model compound Fe0.58Zn0.42F2 have been performed in both of the field-cooling (FC) and zero-field-cooling (ZFC) procedures. There is no evidence of hysteresis between the FC and ZFC protocols within the experimental accuracy. The abse…
We describe the fundamental equations for description of electron-photon interactions in insulating nanostructures. Since the theory for the nanostructures are based on the theory for the bulk crystals, we shall describe elements of the theory for the bulk crystals \cite{knox}-\cite{b2} in the first three subsections.…
It is found experimentally that the coexistence region of a vapor-liquid system or a binary mixture is substantially narrowed when the fluid is confined in a aerogel with a high degree of porosity (e.g. of the order of 95% to 99%). A Hamiltonian model for this system has recently been introduced (J.Donley PRE 55:539,…
Polarized attenuated total reflectance (ATR), grazing angle reflection−absorption, and transmission Fourier transform infrared (FT-IR) spectroscopy methods have been used to investigate the orientation of peptide nanotubes in the functionally relevant environment of ordered phospholipid multibilayers. Eight-residue cy…
Relatively monodisperse, highly luminescent zinc blende ZnSe nanocrystals are synthesized in a hexadecylamine/trioctylphosphine coordination solvent. The controlled growth process affords tunable sample sizes. Pure band-edge fluorescence size-tunable between 2.8 and 3.4 eV is obtained at room temperature with quantum…
The novel compound 1,10-diiodophenanthrene (right) is twisted by 68° owing to I–I repulsion. Density functional calculations with basis sets augmented by iodine pseudopotentials have been performed for this compound and for 2,2′diiodobiphenyl and 1,8-diiodonaphthalene, and the distortion of their structures caused by…
A thermally populatedS=3/2 spin state at room temperature is quite unusual for the coordination chemistry of six-coordinate iron(III) ions. For the complex cation [Fe(L-N4Me2Me2)(S2C6H4)]+, the occurrence of a spin crossover between a low-spin state and an intermediate-spin state is established by structural, magnetic…
Analysis of the dihydrofolate reductase (DHFR) complex with folate by two-dimensional heteronuclear (1H-15N) nuclear magnetic relaxation revealed that isolated residues exhibit diverse backbone fluctuations on the nanosecond to picosecond time scale [Epstein, D. M., Benkovic, S. J., and Wright, P. E. (1995) Biochemist…
A number of derivatives of 1,3-dithienylbenzo[ c ]thiophene have been synthesized. The mono- and dicarboxaldehydes have been elaborated to give new vinylenes and cyanovinylenes. β-Dodecyl- and hexyl-substituted analogues have been prepared. Results from cyclic voltammetric investigation as well as fluorescence studies…
Polymerization of two isomeric heterocyclic monomers, 3-methyl-1-vinylpyrazole and 1-allylimidazole, was investigated under pulsed plasma conditions. Large-scale, progressive variations in polymer compositions were observed with sequential changes in the plasma duty cycles employed, all other plasma variables being he…
Pyruvate kinase from rabbit muscle has been cocrystallized as a complex with MgIIATP, oxalate, Mg2+, and either K+ or Na+. Crystals with either Na+ or K+ belong to the space group P2(1)2(1)2(1), and the asymmetric units contain two tetramers. The structures were solved by molecular replacement and refined to 2.1 (K+)…