Materials Literature
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Li Nb O 3 ∕ Nb -doped SrTiO3 heterojunction was fabricated by pulsed laser deposition. The current-voltage curve of this heterojunction shows good rectifying property and changes with temperature dramatically. For the forward bias, the conduction mechanism changes from Ohmic-like for the low bias voltages to space cha…
Poly(l-lactic acid) was crystallized from the glassy state at different temperatures to produce fully transformed semi-crystalline specimens exhibiting different lamellar morphologies. The materials were tested by dynamic mechanical analysis, where a T g decrease was found with an increasing crystallization temperatur…
The lattice structure of (110)-oriented BiFeO3 epitaxial thin layers has been identified by synchrotron x-ray diffraction. By using (221) and (221¯) peaks in the (HHL) zone, a ground state monoclinic Mb phase has been observed with lattice parameters of (β;am∕√2andcm)=(89.35°;3.985and3.888Å). These results demonstrate…
The authors measure the temperature dependence of the first absorption feature (dE∕dT) for different sizes of CdSe∕ZnS nanocrystals. In contrast to previous experiments, they find that dE∕dT is experimentally identical for all nanocrystal sizes considered and agrees well with the bulk CdSe value. They show that a firs…
Using combined microscopy and optical characterizations, the authors demonstrate effective Er doping into freestanding ZnO nanowires via ion implantation. The Er atoms are observed to take the substitutional sites in ZnO without causing obvious distortion to the host lattice. While the band gap threshold of the Er dop…
The mechanical properties of individual tungsten oxide (WO3) nanowires, directly grown onto tungsten scanning tunneling microscopy tips, have been investigated by a custom-built in situ transmission electron microscopy (TEM) measurement system. Young’s modulii (E) of the individual WO3 nanowires were measured with the…
Twin boundaries (TBs) in ultra-fine grained (UFG) copper prepared by powder metallurgy were investigated using high-resolution transmission electron microscopy (HRTEM) and geometric phase analysis (GPA). Specimens were analyzed both before and after mechanical deformation (compression of 40%) and emphasis placed on th…
Grain boundaries are known to be sources and sinks for bulk vacancies, but the exchange that occurs between the grain boundary and the bulk under a low stress is still obscure. In the present paper, it is shown that grain boundaries may act as sources to emit vacancies when an anelastic deformation occurs under a comp…
The strengthening mechanisms in bimetallic Cu/Ni thin layers are investigated using a hybrid approach that links the parametric dislocation dynamics method with ab initio calculations. The hybrid approach is an extension of the Peierls–Nabarro (PN) model to bimaterials, where the dislocation spreading over the interfa…
Abstract The gelation rates of poly(3‐alkyl thiophenes) (P3AT) are strongly dependent on the pendent alkyl chain length. Poly(3‐hexyl thiophene (P3HT) gels at higher isothermal temperatures than that of poly(3‐dodecyl thiophene), (P3DDT). Gelation rate has been expressed as a combination of a temperature dependent fun…
Magnetic field-induced entropy change has been experimentally studied for phase-separated manganites Eu0.55Sr0.45MnO3 and La0.27Nd0.40Ca0.33 MnO3. The entropy derived from the measured heat capacity exhibits a significant decrease under applied field in a broad temperature range below Curie temperature, and the maximu…
A series of molecular dynamics simulations using the embedded atom method is conducted to investigate crack propagation under mode I loading in a Ni single crystal with and without defects. The crack system (0 0 1)[1 0 0] in a slab of 160 000 atoms was studied. Defects consisting of lines of vacancies were introduced…
Luminescent amorphous silicon nitride films were fabricated by plasma-enhanced chemical vapor deposition at room temperature followed by thermal oxidation at 100°C. Very bright green emissions were clearly observed with the naked eye in a bright room after the samples had been oxidized. The emission peak is located at…
To improve the field emission current density of aligned carbon nanotubes grown by thermal chemical vapor deposition, postgrowth thermal annealing was conducted at 850°C for 1h in vacuum plus at 465°C for 2h in air. It was found that the highest field emission current density significantly improved by a factor of 4 (f…
Single-phase Er2SiO5 nanocrystal aggregates were produced on a large scale using Si nanowire (Si-NW) arrays as templates. A dense array of Si-NWs was grown by vapor-liquid-solid mechanism using Au catalyst on Si (111) substrate. Afterwards, ErCl3∙6H2O dissolved ethanol solution was spin coated and annealed first at 90…
The vibrational fine structure of x-ray photoelectron (XP) spectra of a number of different small hydrocarbon molecules and reaction intermediates adsorbed on Pt(111) and Ni(111) has been investigated in detail. The data for methyl, methylidyne, acetylene, and ethylene can consistently be analyzed within the linear co…
Temperature dependence of electrical properties is studied statistically from 24 p-channel Pt∕SrBi2Ta2O9∕Hf–Al–O∕Si field-effect transistors up to 85°C. They show consistent properties and the distribution of threshold voltage is narrow. The memory window decreases from 1.40to1.15V as temperature increases from 27to85…
Hydrogen atoms play a central role in many biochemical processes yet are difficult to visualize by x-ray crystallography. Spallation neutron sources provide a new arena for protein crystallography with TOF measurements enhancing data collection efficiency and allowing hydrogen atoms to be located in smaller crystals o…
We measured the dynamic structure factor S(Q,omega) of liquid and undercooled water down to 253 K in the Q approximately 0.02-0.1 nm;{-1} momentum transfer region. We observe the neat departure of the apparent speed of sound from the adiabatic regime as a function of decreasing temperature. Our evaluation of the infin…
Abstract Self‐reinforced cellulose films were prepared by incomplete dissolution of commercial microcrystalline cellulose in LiCl/DMAc solvent and subsequent coagulation of regenerated cellulose in the presence of undissolved microcrystalline cellulose. By drawing in wet conditions and subsequent drying, preferred ori…