Nanotexture influence of BaTiO3 particles on piezoelectric behaviour of PA 11/BaTiO3 nanocomposites

The piezoelectric activity of a hybrid ferroelectric nanocomposite, i.e. polyamide 11/barium titanate (BT), has been investigated for different loadings of BT particles. The BT volume fraction (/) was ranging from 0.024 to 0.4 with a particle size of 50, 100, 300 and 700 nm. The influence of polarization mode on the piezoelectric behaviour has been studied. The magnitude of the poling field used in this study is in the same order of magnitude of the one used for bulk BT i.e. significantly lower than for piezoelectric polymers. The optimum piezoelectric coefficient is reached when the amorphous phase of the polymeric matrix is in the liquid state i.e. for a polarization temperature higher than the glass transition and for time constant allowing macromolecular mobility. The composite piezoelectric activity decreases for particles size lower than 300 nm due to the loss of the tetragonal phase. The nanotexture of these particles has been investigated by transmission electron microscopy (TEM) and high-resolution TEM. A core shell structure has been observed. An increase of the longitudinal piezoelectric strain coefficient d33 with the raising of BT volume fraction was shown. Contrary to inorganic piezoelectric ceramics, the dielectric permittivity of hybrid composites remains moderate; therefore it allows the piezoelectric voltage coefficient of composites to be higher than ceramics

Back-side-on-BOX heterogeneously integrated III-V-on-silicon O-band discrete-mode lasers

We demonstrate foundry-fabricated O-band III-V-on-silicon discrete-mode lasers. The laser fabrication follows the back-side-on-buried-oxide laser integration process and is compatible with complex, multilayer, silicon-on-insulator based platforms. A series of devices were characterized, with the best devices producing on-chip powers of nearly 20 mW with Lorentzian linewidths below 20 kHz and a side mode suppression ratio of at least 60 dB

ANGABEN UBER DIE DAMAR-DROSSEL, GEOCICHLA CITRINA (LATH.), VON JAVA,

abstract not availabl

ZUR LEBENSWEISE UND VERBREITUNG VON STACHYRIS MELANOTHORAX (TEMM.)

ABSTRACT NOT AVAILABL

Dielectric relaxations and ferroelectric behaviour of even–odd polyamide PA 6,9

Thermo Stimulated Current (TSC) combined with Dynamic Dielectric Spectroscopy (DDS) have been applied to the investigation of dielectric relaxation modes of an even–odd Polyamide PA 6,9. The correlation between results obtained by both methods allows us to describe precisely the molecular mobility. At high temperature, the various dielectric relaxation phenomena are separated by applying the dielectric modulus formalism. The comparison between the activation enthalpy values obtained by DDS and TSC leads to the assignment of the so-called α mode to cooperative movements of polymeric sequences. Molecular mobility of PA 6,9 is compared with the one of PA 11. The piezoelectric activity of PA 6,9 is shown and analyzed

Diodes with Breakdown Voltages Enhanced by the Metal-Insulator Transition of LaAlO3_3-SrTiO3_3 Interfaces

Using the metal-insulator transition that takes place as a function of carrier density at the LaAlO$_3$-SrTiO$_3$ interface, oxide diodes have been fabricated with room-temperature breakdown voltages of up to 200 V. With applied voltage, the capacitance of the diodes changes by a factor of 150. The diodes are robust and operate at temperatures up to 270 C

The three-dimensional structure of the bifunctional proteinase k/α-amylase inhibitor from wheat (PKI3) at 2.5 Å resolution

AbstractWheat germ contains an inhibitor for proicinase K, called PK13 (M1 ∼ 19600) which simultaneously inhibits α-amylase. PK13 was crystallized, space group P21, α = 43.02 (5) Å, n = 65.18 (7) Å, c = 32.33 (4) Å, β = 112.79 (9), X-ray data were collected to 2.5 Å resolution, the structure solved by molecular replacement on the basis of the atomic coordinates of the homologous Erythrina caffra DE-3 inhibitor, and refined with simulated annealing techniques with a current R-factor of 21%. The three-dimensional structure of PK13 is stabilized by two disulfide bridges and has a central β-barrel with distorted β-structure. In analogy to related inhibitors, the binding site for proteinase K is assumed to be located on the surface of the protein (amino acids residues 66–67), although the 75–76 peptide bond is cleaved upon binding

Electric-field-induced pyroelectric order and localization of the confined electrons in LaAlO3/SrTiO3 heterostructures

With infrared ellipsometry, x-ray diffraction, and electric transport measurements we investigated the electric-field-effect on the confined electrons at the LaAlO3/SrTiO3 interface. We obtained evidence that the localization of the electrons at low temperature and negative gate voltage is induced, or at least strongly enhanced, by a pyroelectric phase transition in SrTiO3 which strongly reduces the lattice polarizability and the subsequent Coulomb screening. In particular, we show that the charge localisation and the polar order of SrTiO3 both develop below about 50 K and exhibit similar, unipolar hysteresis loops as a function of the gate voltage. Our findings suggest that the pyroelectric order also plays an important role in the quantum phase transition at very low temperatures where superconductivity is suppressed by an electric field.Comment: 5 pages, 4 figures, supplementary materia

A clinicopathological analysis of 151 odontogenic tumors based on new WHO classification 2022: A retrospective cross-sectional study

Background: Odontogenic tumors are a diverse group of lesions with a variety of clinical behavior and histopathologic subtypes, from hamartomatous and benign to malignant. The study aimed to examine the clinical and pathological features of odontogenic tumors in Baghdad over the last 11 years (2011–2021). Materials and Methods: The present retrospective study analyzed all formalin-fixed, paraffin-embedded tissue blocks of patients diagnosed with an odontogenic tumor that were retrieved from archives at a teaching hospital/College of Dentistry in Baghdad University, Iraq, between 2011 and 2021. The diagnosis of each case was confirmed by examining the hematoxylin and eosin stained sections by two expert pathologists. Data from patients' case sheets were collected, including age, gender, location, and histopathological information. The type of lesions was evaluated based on the World Health Organization's most recent classification (March 2022). Results: There were 151 odontogenic tumor during this period. The most common type (39.1%) was Solid ameloblastoma. The mandibular tumors (76.8%) were more than the maxillary tumors (23.2%). The female to male ratio was 1.1:1. The most cases are found between the 2nd and 5th decades of life. Conclusions: Solid ameloblastoma was the most common odontogenic tumor, while primordial odontogenic tumor was the rarest, Odontogenic tumors were slightly more common in females than in males, the most common cases occur in the mandible., the outcome of the study gives valuable information regarding the patients' profile and type of odontogenic tumors over 11 years, which could aid in the early diagnosis and enhance the intervention