Materials Literature
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Azobenzene E<==>Z photoisomerization, following excitation to the bright S(pi pi*) state, is investigated by means of ab initio CASSCF optimizations and perturbative CASPT2 corrections. Specifically, by elucidating the S(pi pi*) deactivation paths, we explain the mechanism responsible for azobenzene photoisomerization…
We report on an efficient route to design large macrocyclic polymers of controlled molar mass and narrow dispersity. The strategy is based on the synthesis of a triblock copolymer ABC, in which the long central block B is extended by two short A and C sequences bearing reactive antagonist functions. When reacted under…
Mn2+-doped ZnS nanocrystals with an amine-capping layer have been synthesized and used for the fluorescence detection of ultratrace 2,4,6-trinitrotoluene (TNT) by quenching the strong orange Mn2+ photoluminescence. The organic amine-capped nanocrystals can bind TNT species from solution and atmosphere by the acid-base…
One of the key challenges in anticancer therapy is the toxicity and poor bioavailability of the anticancer drugs. Nanotechnology can play a pivotal role by delivering drugs in a targeted fashion to the malignant cells that will reduce the systemic toxicity of the anticancer drug. In this report, we show a stepwise dev…
Carbons have been prepared by the low-temperature pyrolysis, under argon, of a number of long-chain polymers. We have found that the resistivity (Ω cm -1 ) varies considerably with the temperature of pyrolysis; thus, for ammonium polyacrylate, the resistivity of that pyrolyzed at 600 °C is 9.7 × 10 4 Ω cm -1 whereas t…
A soft method for purifying multi-wall carbon nanotubes (N-doped and undoped) is presented. The technique includes a hydrothermal/ultrasonic treatment of the material in conjunction with other subsequent treatments, including the extraction of polyaromatic compounds, dissolution of metal particles, bundle exfoliation,…
The ground-state properties of small silver clusters Agn (2⩽n⩽24) have been studied using a linear combination of atomic Gaussian-type orbitals within the density functional theory. The results show that the Ag13 clusters, due to their noticeable magnetic moment and their considerable highest occupied-lowest unoccupie…
Hetero- und Homodreikernkomplexe von Thorium und Uran mit gemischtvalenten Metallzentren wurden elektrochemisch (siehe Bild, Tpy=2,2′:6′,2′′-Terpyridin), spektroskopisch und hinsichtlich ihrer magnetischen Eigenschaften analysiert. Dabei zeigte sich eine beträchtliche elektronische Wechselwirkung, wobei die Kommunikat…
The yields of H2 and Cl- were determined in the radiolysis of deaerated, aerated, and water mixtures of poly(vinyl chloride) (PVC) powders with gamma-rays and 5 MeV He ions. H2 yields with gamma-rays are low at about 0.25 molecule/100 eV and they double with He ion radiolysis indicating a second order formation proces…
We have prepared comparable-diameter ZnO and Zn 1- x Co x O nanowires with both circular and hexagonal cross-sections. The average diameters are ∼113 and ∼134 nm for cylindrical and hexagonal nanowires, respectively. The as-grown nanowires have been characterized via structure, electrical conductivity and photolumines…
We report the formation of embedded ZnO quantum dots (QDs) by Zn and F ion sequential implantation and subsequent annealing. Optical absorption and photoluminescence spectrum measurements, transmission electron microscopy bright field images and selected area electron diffraction patterns indicate that ZnO QDs were fo…
A simple synthesis method of gold nanoparticles dispersed at the silica surface which allows a progressive and controlled increase of Au particle population is described. An important step of the preparation is treatment in H 2 at 573 K, which allows cleaning the surface of Au from chlorine, a frequently present impur…
For semicrystalline polymers there is an ongoing debate at what temperature the immobilized or rigid amorphous fraction (RAF) devitrifies (relaxes). The question if the polymer crystals aremelting first and simultaneously theRAFdevitrifies or the RAF devitrifies first and later on the crystals melt cannot be answered…
The texture of ultrafine-grained Al alloy AA6016 produced by accumulative roll bonding (ARB) has been measured by neutron diffraction. The starting texture consists of a strong cube component. During ARB, this texture breaks down and a texture typical for rolling of face-centered cubic metals with high stacking fault…
We investigate the hydrogen adsorbing characteristics of single-walled carbon nanotubes (CNTs) through fundamental molecular dynamics simulations that characterize the role of ambient pressure and temperature, the presence of surface charges on the CNTs, inclusion of metal ion interconnects, and nanocapillary effects.…
The insulator to metal transition in $\mathrm{La}\mathrm{Ti}{\mathrm{O}}_{3}$ induced by La substitution via Sr is studied within multiband exact diagonalization dynamical mean field theory at finite temperatures. It is shown that weak hole doping triggers a large interorbital charge transfer, with simultaneous electr…
It has become apparent through experimentation at the micro- and nanolevels that the crystalline defects known as dislocations have significant effects on a material’s properties. Accordingly, a complete material state description must include the characterization of the dislocated state. However, this characterizatio…
High purity in high yield L-lactide was prepared using a new purification method, and poly-L-lactide (PLLA) with ultra-high weight average molecular mass and narrow polydispersity index was synthesized by ring-opening polymerization. The effects of the purification method on the purity and yield of L-lactide were inve…
Lead sulfide nanocrystals (NCs) along with nanothreads and nanosheets were synthesized in the presence of water soluble polymers such as poly(styrene sulfonate) sodium salt (PSS) and poly(vinyl pyrolidone) (PVP) in aqueous phases at relatively mild temperature of 80 °C. The amount of each polyelectrolyte was systemati…
This work reports the successful use of a combination of non-conventional methods of synthesis (mechanosynthesis) and sintering (spark plasma sintering, SPS) for the preparation of nanostructured 0.92PbZn(1/3)Nb(2/3)O(3)-0.08PbTiO(3) (PZN-PT) ceramics. With this approach we achieve not only the stabilization of the PZ…