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lmpressum / Masthead
Optical absorption by small metallic particles
We study theoretically the dependence of absorption by small metallic particles on particle shape and wave polarization in the IR frequency range. We examine the electric and magnetic absorption by small particles. The particles may be either larger or smaller than the electron mean free path. We show that for asymmet…
Intramolecular Reactions of Temporarily Silicon-Tethered Molecules
All articles of this category The Temporary Silicon Connection transforms a potential inter molecular reaction into an intra molecular one, by transiently connecting both partners through a silicon linkage. In addition to entropic advantages, temporary connectivity forces regioselectivity and high stereoselectivity of…
Hydrogen-Bond Acceptor and Donor Properties of Divalent Sulfur (Y-S-Z and R-S-H)
The hydrogen-bond acceptor ability of divalent sulfur in Y —S— Z systems, Y , Z = C, N, O or S, and the donor ability of thiol S—H have been studied using crystallographic data retrieved from the Cambridge Structural Database. Of 1811 Y —S— Z substructures that co-occur with N—H or O—H donors, only 86 (4.75%) form S..…
Determination of the universality class of Gadolinium
We resolve a longstanding puzzle for the static and dynamic critical behavior of Gadolinium by a combined theoretical and experimental investigation. It is shown that the spin dynamics of a three dimensional ferromagnet with hcp lattice structure and a spin-spin interaction given by both exchange and dipole-dipole int…
The Use of the Pseudo-Voigt Function in the Variance Method of X-ray Line-Broadening Analysis
A modified application of the variance method, using the pseudo-Voigt function as a good approximation to the X-ray diffraction profiles, is proposed in order to obtain microstructural quantities such as the mean crystallite size and root-mean-square (r.m.s.) strain. Whereas the variance method in its original form is…
In vivo biocompatibility and biostability of modified polyurethanes
Modified segmented polyurethanes were examined for biostability and biocompatibility using an in vivo cage implant system for time intervals of 1, 2, 3, 5, and 10 weeks. Two types of materials were used: polyether polyurethanes and polycarbonate polyurethanes. Two unmodified polyether polyurethanes (PEUU A' and SPU-PR…
Raman- and infrared-active phonons in hexagonalYMnO3: Experiment and lattice-dynamical calculations
Raman-scattering and far-infrared-transmission spectra of hexagonal ${\mathrm{YMnO}}_{3}$ (space group ${P6}_{3}cm)$ are reported and discussed. In the Raman spectra measured in several exact scattering configurations, lines of ${A}_{1}$ (at 148, 190, 257, $\ensuremath{\sim}300$, 433, 459, and 681 cm${}^{\ensuremath{-…
Recent innovations in edible and/or biodegradable packaging materials
Certain newly discovered characteristics of natural biopolymers should make them a choice material to be used for different types of wrappings and films. Edible and/or biodegradable packagings produced from agricultural origin macromolecules provide a supplementary and sometimes essential means to control physiologica…
Self‐Assembly of Bisurea Compounds in Organic Solvents and on Solid Substrates
Abstract New low molecular weight gelators based on the structure RNHCONHXNHCONHR have been synthesized and tested for their ability to cause gelation of organic solvents. Compounds 2 (R = n ‐dodecyl, X = ‐(CH 2 ) 9‐ ), 3 (R = n ‐dodecyl, X = ‐(CH 2 ) 12‐ ), 4 (R = n ‐dodecyl, X = 4, 4′‐biphenyl), and 5 (R = benzy…
Li and Na Diffusion in TiO2 from Quantum Chemical Theory versus Electrochemical Experiment
Diffusion of Li and Na ions in TiO 2, anatase, has been studied using theoretical (quantum chemical ab initio periodic Hartree−Fock and a modified semiempirical INDO) as well as electrochemical (chronocoloumetry) methods. On the basis of the theoretical calculations, the geometry of equilibrium and transition states f…
Constrained Densification of Alumina/Zirconia Hybrid Laminates, I: Experimental Observations of Processing Defects
Various forms of damage were observed in pressure‐less‐sintered Al 2 O 3 /ZrO 2 symmetric laminates and asymmetric laminates (bilayers) fabricated by tape casting and lamination. These defects included channel cracks in the ZrO 2 layers, Al 2 O 3 edge‐effect cracks parallel to the layers, delamination in the Al 2 O 3…
Electrochemical Properties of Quaternary Ammonium Salts for Electrochemical Capacitors
The limiting reduction and oxidation potentials and electrolytic conductivities of new quaternary ammonium salts were examined for electrochemical capacitor applications, whose anions have already been tested as lithium salts for lithium battery applications. The anodic stability was in the following order The electro…
Comparison of Structural Models of Mixed-Layer Illite/Smectite and Reaction Mechanisms of Smectite Illitization
Abstract This paper compares mechanisms of the reaction of smectite to illite, in light of structural models for interstratified illite/smectite (I/S). The crystal structure of I/S has been described previously by a nonpolar and polar 2:1 layer model. In a nonpolar model, individual 2:1 layers are chemically homogeneo…
New Strategies for the Generation of Large Heteropolymetalate Clusters: The β‐B‐SbW9 Fragment as a Multifunctional Unit
Abstract Proceeding from the α‐ B ‐SbW 9 O 33 fragment 1 , various novel large heteropolyanions ([Na 2 Sb 8 W 36 O 132 (H 2 O) 4 ] 22– ( 2 ), [Sb 2 W 22 O 74 (OH) 2 ] 12− ( 3 ) and [Sb 2 W 20 M 2 O 70 (H 2 O) 6 ] (14−2 n )− ( 4 ); M n + = Fe 3+ , Co 2+ , Mn 2+ , Ni 2+ ) have been obtained in crystalline form by system…
Nonlinear Optical Properties of Liquid Crystals and Polymer Dispersed Liquid Crystals
Physical properties of thermotropics basic nonlinear optics light-induced reorientation thermal effects linear and nonlinear optical properties of PDLC.
The Crystal Structure of Citrate Synthase from the Hyperthermophilic Archaeon Pyrococcus furiosus at 1.9 Å Resolution,
The crystal structure of the closed form of citrate synthase, with citrate and CoA bound, from the hyperthermophilic Archaeon Pyrococcus furiosus has been determined to 1.9 A. This has allowed direct structural comparisons between the same enzyme from organisms growing optimally at 37 degrees C (pig), 55 degrees C (Th…
Cloning and analysis of the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) biosynthesis genes of Aeromonas caviae
A 5.0-kbp EcoRV-EcoRI restriction fragment was cloned and analyzed from genomic DNA of Aeromonas caviae, a bacterium producing a copolyester of (R)-3-hydroxybutyrate (3HB) and (R)-3-hydroxyhexanoate (3HHx) [P(3HB-co-3HHx)] from alkanoic acids or oils. The nucleotide sequence of this region showed a 1,782-bp poly (3-hy…