Materials Literature
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Guest–host composites with improved dispersion of guest species can be fabricated using a new method that exploits the confined space between the silica walls and templated aggregates in as-prepared mesoporous materials. This produces mesoporous functional composites with high oxide dispersions with potential applicat…
We report on measurements of the crystal structure and hole density in a series of as-grown and annealed GaMnAs samples. The measured hole densities are used to obtain the fraction of incorporated Mn atoms occupying interstitial and substitutional sites. This allows us to make a direct comparison of the measured latti…
We demonstrate tunable room-temperature amplified spontaneous emission and lasing from blue-emitting core-shell CdS∕ZnS nanocrystals (NCs) stabilized in a sol-gel derived silica matrix. Variable stripe length measurements show that these NC-silica composites have a modal gain of ∼100cm−1 at room temperature. Coating m…
Polymerization of polyaniline in the presence of carbon nanotubes results in a soluble carbon nanotube/polyaniline composite (Figure, left) displaying enhanced thermal and electrical properties. Polyaniline in the proximity of nanotubes grows in a more planar conformation due to strong π–π interactions simultaneously…
Single-crystalline gold nano- and microplates with triangular or hexagonal shapes are synthesized by reduction of HAuCl(4) in lyotropic liquid crystal (LLC) mainly made of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers and water after adding a small amount of capping agents, cetyltrim…
Different ways of dealing with one-dimensional (1D) spectra, measured e.g. in the Compton scattering or angular correlation of positron annihilation radiation (ACAR) experiments are presented. On the example of divalent hexagonal close packed metals it is shown what kind of information on the electronic structure one…
It is experimentally demonstrated that an adiabatic demagnetization - remagnetization scheme, where the Zeeman order of abundant nuclei is first adiabatically converted into the dipolar order, and then, into the Zeeman order of rare nuclei, can significantly increase polarization of rare nuclei compared to the convent…
Density--functional simulations have been performed on Na$_{55}$, Na$_{92}$ and Na$_{142}$ clusters in order to understand the experimentally observed melting properties [M. Schmidt \textit{et al.}, Nature (London) \textbf{393}, 238 (1998)]. The calculated melting temperatures are in excellent agreement with the exper…
The influence of experimental noise on densities rho(p) reconstructed by the Cormack method from their line projections, e.g. 2D ACAR spectra, is investigated. Simulations of statistical noise are performed for various sets of 2D spectra for two model rho(p) having the cubic symmetry. For the reconstructed densities p…
We describe defects - dislocations and disclinations - in the framework of Riemann-Cartan geometry. Curvature and torsion tensors are interpreted as surface densities of Frank and Burgers vectors, respectively. Equations of nonlinear elasticity theory are used to fix the coordinate system. The Lorentz gauge yields equ…
Phase transitions in CsPbCl$_3$ crystals have been explored by photoacoustic (PA) method in a wide temperature range of 150--300 K. The PA signals, induced by ns-pulsed laser excitation of electronic states and detected with a piezoelectric transducer, are thermoelastic ultrasonic waves lasting for hundreds of microse…
Three-terminal electrochemical transistors are manufactured from thin films of poly(3,4-ethylenedioxythiophene): poly(styrene sulfonic acid), and form the basis of oscillatory and digital circuits, thus opening the door for logic systems based on \(electronic paper\). The transistors use ions and electrons as signal c…
Silicon nanoparticles are synthesized from a mixture of argon/silane in a continuous flow atmospheric-pressure microdischarge reactor. Particles nucleate and grow to a few nanometers (1-3 nm) in diameter before their growth is abruptly terminated in the short residence time microreactor. Narrow size distributions are…
Novel polymer core–shell nanoparticles that exhibited a pH-dependent lower critical solution temperature (LCST) have been synthesized. The nanoparticles displayed stable structure in a nominal physiological environment but deformed and precipitated in an acidic environment, thereby releasing the enclosed drug molecule…
We have developed a unique micromechanical method to extract extremely thin graphite samples. Graphite crystallites with thicknesses ranging from 10 to 100nm and lateral size ∼2μm are extracted from bulk. Mesoscopic graphite devices are fabricated from these samples for electric field-dependent conductance measurement…
We report the immobilization of various enzymes in mesoporous silica (MS) spheres followed by encapsulation via the layer-by-layer assembly of multilayered nanocomposite thin shells. A range of enzymes with different molecular sizes and isoelectric points (pI) (e.g., catalase, peroxidase, cytochrome C, and lysozyme) h…
Fe/Ti oxide films with graded composition profiles have been prepared from aqueous metal‐fluoro complex solutions by the liquid phase deposition method. Films were deposited from a solution, in which the (NH 4 ) 2 TiF 6 solution was added under a controlled flow rate into the FeOOH–NH 4 F·HF solution. Transmission ele…
We report the results of a study of the growth of pores in n-CdSe single crystals using anodic etching techniques. Upon anodization in dark, a nonuniform distribution of pores was produced. However, anodic dissolution of the material under in situ UV illumination proves to result in uniform distribution of pores stret…
2,3-Anhydroerythritol ( 1a ) and 2,3-anhydro- dl -threitol ( 1b ) were polymerized using boron trifluoride diethyl etherate (BF 3 ·OEt 2 ) as a cationic initiator. The polymerizations of 1a and 1b proceeded through a ring-opening reaction with a proton-transfer reaction to produce hyperbranched carbohydrate polymers (…
An integral equation theory is developed for the structure and thermodynamics of melts of random copolymers. The molecules are modeled as flexible chains with a random sequence of two types of sites, with square well potentials between sites. The polymer reference interaction site model (PRISM) integral equation theor…