Materials Literature
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The reactivities of metallic nanosystems in catalytic processes are considered. The activities of nanoparticles in catalysis are due to their unique microstructures, electronic properties and high specific surfaces of the active centres. The problems of increasing the selectivities of catalytic processes are discussed…
A series of nanocomposite materials that consisted of emeraldine base of polyaniline and layered montmorillonite (MMT) clay were prepared by effectively dispersing the inorganic nanolayers of MMT clay in organic polyaniline matrix via in-situ polymerization. Organic aniline monomers were first intercalated into the in…
2-(N-Phthalimido)ethanol (NPE) was prepared by reacting phthalic anhydride with ethanolamine in dimethy formamide medium. The NPE thus obtained was reacted with methacryloyl chloride in the presence of triethylamine to form the monomer, 2-(N-Phthalimido)ethyl methacrylate (NPEMA). Free radical polymerization technique…
TROSY-based HN(CO)CA 2D and 3D pulse schemes are presented for measurement of (13)C(alpha)-(13)C(beta) dipolar couplings in high molecular weight (15)N,(13)C,(2)H-labeled proteins. In one approach, (13)C(alpha)-(13)C(beta) dipolar couplings are obtained directly from the time modulation of cross-peak intensities in a…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTEffect of an Internal Anthranilamide Turn Unit on the Structure and Conformational Stability of Helically Biased Intramolecularly Hydrogen-Bonded DendronsBaohua Huang and Jon R. ParquetteView Author Information Department of Chemistry The Ohio State University Columbus…
A new equation describing the behavior of the structural relaxation time, tau(T,P), as a function of both pressure and temperature, is discussed. This equation has been derived from the Adam-Gibbs theory by writing the configurational entropy, S(c), in terms of the excess thermal heat capacity and of the molar thermal…
We visualize undulations in layered systems using a cholesteric stripe phase with a macroscopic supramicron periodicity. The wave vector of stripe pattern is in the cell's plane. The undulation is induced by an in-plane magnetic field normal to the stripes. The observed displacement of layers is much larger than the v…
A method is suggested for the coating of micron-sized particles by polymeric films based on surface-controlled precipitation. Polymer particles were coated by dextran and DNA in a water/ethanol mixture containing multivalent cations. A theoretical model for depositing polymers on colloidal particles is presented using…
We investigate two-dimensional (2D) melting in the presence of a one-dimensional (1D) periodic potential as, for example, realized in recent experiments on 2D colloids subjected to two interfering laser beams. The topology of the phase diagram is found to depend primarily on two factors: the relative orientation of th…
Five generations of poly(propylene imine) dendrimers have been modified by palmityl and adamantyl endgroups via a thiourea linkage. The synthesis of the thiourea dendrimers DAB-dendr-(NHCSNHAd)(n) and DAB-dendr-(NHCSNHC(16)H(33))(n) (n = 4, 8, 16, 32, 64) proceeds smoothly via the amino-terminated DAB dendrimer and th…
The transport and relaxation properties of a molecular supercooled liquid on an isobar are studied by molecular dynamics. The molecule is a rigid heteronuclear biatomic system. The diffusivity is fitted over four orders of magnitude by the power law $D\ensuremath{\propto}(T\ensuremath{-}{T}_{c}{)}^{{\ensuremath{\gamma…
The rotational dynamics of a supercooled model liquid of rigid A-B dumbbells interacting via a Lennard-Jones potential is investigated along one single isobar. The time-temperature superposition principle, one key prediction of mode-coupling theory (MCT), was studied for the orientational correlation functions C(l). I…
Titanium-containing mesoporous molecular sieve Ti−MCM-41 has been synthesized using colloidal silica as the silicon source and TiCl 3 solution as the titanium source and was characterized by X-ray diffraction, N 2 adsorption, UV−vis, and UV−Raman spectroscopies. The formation of anatase TiO 2 can be avoided during the…
Mesoporous silica materials (MCM-41) were characterized by 13 C and 29 Si magic angle spinning (MAS) NMR. 13 C chemical shifts reveal a high content of gauche conformations in the chain of cationic surfactant molecules within the nanopores. 13 C T 1 's and proton to carbon cross-polarization times ( T CH ) demonstrate…
A statistical mechanical treatment is given of the confinement of a wormlike polymer in an entangled solution to a tube, yielding quantitative predictions for the average tube diameter D(e) and macroscopic plateau modulus G, in the tightly entangled regime in which D(e) is much less than the persistence length L(p). T…
The lattice parameters of MgB2 up to pressures of 8 GPa were determined using high-resolution x-ray powder diffraction in a diamond anvil cell. The bulk modulus, B0, was determined to be 151 +-5 GPa. Both experimental and first-principles calculations indicate nearly isotropic mechanical behavior under pressure. This…
Microprocessor powers are increasing at a phenomenal rate, which requires very small thermal resistance between the die (chip) and the ambient, if the current economical methods of conduction and convection cooling are to be utilized. A typical thermal solution in flip chip technology utilizes two levels of thermal in…
This work presents a step furthering a new perspective of proactive control of the spin-exciton dynamics in the quantum limit. Laser manipulation of spin-polarized optical excitations in a semiconductor nanodot is used to control the spin dynamics of two interacting excitons. Shaping of femtosecond laser pulses keeps…
We report on the ESR, magnetization and magnetic susceptibility measurements performed over a large temperature range, from 1.5 to 750 K, on high-quality stoichiometric LiNiO2. We find that this compound displays two distinct temperature regions where its magnetic behavior is anomalous. With the help of a statistical…
During the directional solidification of peritectic alloys, two stable solid phases (parent and peritectic) grow competitively into a metastable liquid phase of larger impurity content than either solid phase. When the parent or both solid phases are morphologically unstable, i.e., for a small temperature gradient/gro…