Materials Literature
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CuxS nanocrystals (NC’s) are reported. The samples are prepared by a CdS-to-CuxS chemical conversion from the glasses originally containing CdS NC’s. A room-temperature linear absorption of the converted samples shows several well resolved peaks with spectral positions from red to blue. These spectral features are exp…
Thin film ferroelectrics with polarization gradients normal to the growth surface readily form when gradients in temperature, strain, or composition are coupled to the polarization vector in ferroelectric materials. This letter describes the formation of thin films of potassium tantalum niobate with graded polarizatio…
Extremely stiff macromolecules in the form of “hairy rods” or more precisely “molecular bottlebrushes” (without a handle) are easily accessible by the polymerization of polymacromonomers. As anticipated from their high degree of stiffness, these molecules form lyotropic, liquid‐crystalline phases, although they consis…
Cyclic tetrameric units (··Mn-NC-Fe-CN··)4 (depicted on the right) construct the two-dimensional network of the title compound. The layers thus formed are linked together by van der Waals contacts. The compound displays metamagnetism: ferromagnetic coupling is observed within layers and antiferromagnetic coupling betw…
π-Stacking interactions between adjacent aromatic ligand fragments of L− separated by approximately 3.4 Å provides a pathway for weak ferromagnetic coupling in the tetramer [Mn4L4](PF6)4 (1). The cavity of L− is too large for a single MnII ion; instead the tetramer 1 comprises a Mn4 tetrahedron, with a ligand L− attac…
An air bubble trapped in water by an oscillating acoustic field undergoes either spherical or nonspherical pulsations depending on the strength of the forcing pressure. Two different instability mechanisms (the Rayleigh-Taylor instability and parametric instability) cause deviations from sphericity. Distinguishing the…
Novel, polymeric linear chains of Keggin polyoxometalate units PMnW11O39 linked through Mn-O-W bridges (see picture below) are present in the structure of the title compound 1. The chains alternate with layers of the organic donor bis(ethylenedithio)tetrathiafulvalene (ET). Compound 1 promises interesting material pro…
Viscometry and dynamic light scattering (DLS) were used to study suspensions of colloidal particles which interact like hard spheres. The rate of ``structural relaxation'' of microscopic density fluctuations, indicated by the long-time diffusion coefficient measured by DLS at the peak of the static structure factor, w…
We have measured Raman spectra of diamond with nanometer size, called cluster diamond. The Raman bands assigned to sp2 and sp3 clusters have been observed at around 1600 and 1322 cm−1, respectively. This result suggests that the cluster diamond slightly contains the sp2 cluster. The Raman band assigned to sp3 cluster…
A detailed study of doped LaMn${\mathrm{O}}_{3}$ with fixed carrier concentration reveals a direct relationship between the Curie temperature ${T}_{c}$ and the average ionic radius of the La site $〈{r}_{A}〉$, which is varied by substituting different rare earth ions for La. With decreasing $〈{r}_{A}〉$, magnetic order…
Abstract Six new polyether azomethines were synthesized by melt and solution polycondensation of six different diamines with 4,4′‐[1,4‐phenylene bis(oxy)] bisbenzaldehyde. The polymers synthesized by solution method are yellow to white in color and had inherent viscosities up to 0.59 dL/g in concentrated H 2 SO 4 . Th…
Abstract Six nearly monodisperse substituted poly(styrene) homopolymers, poly(styrene) (PS), poly(2‐methylstyrene) (P2MS), poly(3‐methylstyrene) (P3MS), poly(4‐methylstyrene) (P4MS), poly(tertiary‐butylstyrene) (PtBS), and poly(α‐methylstyrene) (FαMS) were anionically polymerized and subsequently saturated using heter…
Abstract 4,4′‐Binaphthyl‐1,1′,8,8′‐tetracarboxylic dianhydride was synthesized from 4‐chloro‐1,8‐naphthalic anhydride and polymerized with aromatic and pliphatic diamines in m ‐cresol or N ‐methyl‐2‐pyrrolidinone (NMP). The polyimides, except for two derived from p ‐phenylenediamine and hydrazine, are soluble in 1,1,2…
Abstract Three N , N ′‐bis (glycidyl ester imide) of pyromellitic acid (diepoxides) were prepared and were used as chain extenders for poly (ethylene terephthalate) (PET) and poly (butylene terephthalate) (PBT). The typical reaction conditions for the coupling of the polyester macromolecules were heating with the chai…
It is the intention of this paper to rigorously clarify the role of the occupation numbers in the current practical applications of the density functional formalism. In these calculations one has to decide how to distribute a given, fixed number of electrons over a set of single-particle orbitals. The conventional cho…
There are two stereochemical classes of hydratase-dehydratase enzymes. Those that catalyze the addition of water to alpha, beta-unsaturated thioesters give syn addition-elimination stereochemistry, whereas those that catalyze the addition of water to conjugated carboxylate substrates give anti stereochemistry. This di…
Classification of admixtures influence of admixtures on nucleation - homogeneous nucleation heterogeneous nucleation secondary nucleation influence of admixtures on crystal growth - the role of the solid surface, the role of the interphase solid - liquid influence of admixtures on crystal shape influence of solvents d…
We consider (AlAs)_n/(GaAs)_n superlattices with random thickness fluctuations Delta-n around the nominal period n. Using three-dimensional pseudopotential plane-wave band theory, we show that (i) any amount Delta-n/n of thickness fluctuations leads to band-edge wavefunction localization, (ii) for small Delta-n/n the…
Abstract Polymer blends based on high‐density polyethylene (HDPE) and acrylonitrile butadiene rubber (NBR) were prepared by a melt blending technique. The mixing parameters such as temperature, time, and speed of mixing were varied to obtain a wide range of properties. The mixing parameters were optimized by evaluatin…
Using a functional lactose permease mutant devoid of Cys (C-less permease), each amino acid residue in putative transmembrane helix V was replaced individually with Cys (from Met145 to Thr163). Of the 19 mutants, 13 are highly functional (60-125% of C-less permease activity), and 4 exhibit lower but significant lactos…