Tetragonal La-modified lead zirconate titanate ceramics with a Zr/Ti ratio of 40/60 (x/40/60) with La contents (x) between 0 and 21 at. % were prepared by the mixed oxide method and were subsequently characterized using dielectric spectroscopy. Small La contents tended to diffuse the dielectric response in the temperature region around the phase transition, however, no distinct changes were observed in the paraelectric region. Compositions with intermediate La contents showed a thermally driven (spontaneous) transformation from a relaxor to a normal ferroelectric, i.e., micro-macro domain switching. Materials with a high La content exhibited typical relaxor ferroelectric behavior. The relative thermodynamic stability of the ensemble of micropolar regions is then discussed in reference to that of the long-range ferroelectric state.

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Background: Prior research on Child Protective Services (CPS) involvement among at-risk youth focuses on their roles as parents perpetrating maltreatment against biological offspring. Given family complexity and assortative partnering, measuring all CPS involvement -as perpetrators and non-offending parents of victims -provides new insight into intergenerational maltreatment patterns.Objectives: Our objective was to investigate the risk of multiple forms of parent or perpetrator CPS involvement (PP-CPS) by age 25, among those exposed to three forms of adversity in their late teens (at ages 14-17): alleged victim on a CPS investigation, out-of-home care (OHC), and poverty. Participants and setting:We used a sample of 36,475 individuals born in 1990-1991 from the Wisconsin Data Core longitudinal administrative database, and tracked their involvement in CPS, OHC, and the food assistance program (SNAP) over time. Our sample consisted of individuals who, at ages 14-17, met one of the following criteria: were in OHC; had CPS involvement as a victim but no OHC (CPSV group), or received food assistance without CPSV or OHC (SNAP group).Methods: Using logistic regression, we modeled four forms of PP-CPS involvement: parentperpetrator, resident parent non-perpetrator, nonresident parent non-perpetrator, and non-biological parent-perpetrator.Results: Predicted risks of any PP-CPS involvement by age 25 were 10 % (SNAP group), 17-22 % (CPSV group), and 26-33 % (OHC group); among OHC youth known to have a biological *

Photoluminescence spectra of relatively pure GaAs display four emission bands at low temperatures, with energies near 1.51,1.49,1.455, and 1.42 eV. We report evidence that the 1.49-, 1.45-, and 1.42-eV bands are, respectively, a donor-acceptor recombination band, as suggested by Gershenzon, and two weaker replicas displaced by one and two phonons. With increasing temperature in the range from 25 to 35°K, the 1.49-eV band shifts slightly toward higher energy and is quenched in favor of the 1.51-eV band, while the total emission remains constant. The two lower energy bands change in frequency and intensity in exactly the same manner as the 1.49-eV band. We interpret the shift toward higher energy as due to an increasing importance of recombination of more closely spaced donor-acceptor pairs, and the quenching of the recombination band as due to increasing ionization of the donors. In addition, slight variations of the properties of the 1.49-eV band with increasing excitation intensity were noted which are compatible with the donor-acceptor recombination hypothesis.

A comparison of spectroscopic and microscopic observations of ion-induced intermixing in InGaAs/InP quantum wells Appl.