Magnetic Resonance Studies of Half-Metallic Epitaxial CrO2 Thin Films Grown on Differently Oriented TiO2 Substrates

The results of structural and ferromagnetic resonance (FMR) investigations of epitaxial half- metallic chromium dioxide (CrO₂) thin films of thicknesses between 58?nm and 540?nm grown by chemical vapor deposition (CVD) on (100) and (110)-oriented TiO₂ single crystal substrates are presented. The angular dependences of the FMR spectra in different experimental geometries were obtained. Effective magnetic anisotropies of epitaxially grown CrO₂ films of different thicknesses on strain and strain-free surfaces of TiO₂ substrates were estimated. The results indicate that the magnetic behavior of the CrO₂ films results from a competition between the magnetocrystalline and strain anisotropies. It has been revealed that the strain anisotropy dominates in the films grown onto (100)-oriented TiO₂ substrates. On the contrary, the films grown onto (110)-oriented substrates demonstrate strain-free magnetic anisotropy behavior.     

Magnetic phase composition of strontium titanate implanted with iron ions

Thin magnetic films were synthesized by means of implantation of iron ions into single-crystalline (1 0 0) substrates of strontium titanate. Depth-selective conversion electron Mössbauer spectroscopy (DCEMS) indicates that origin of the samples magnetism is α-Fe nanoparticles. Iron-substituted strontium titanate was also identified but with paramagnetic behaviour at room temperature. Surface magneto-optical Kerr effect (SMOKE) confirms that the films reveal superparamagnetism (the low-fluence sample) or ferromagnetism (the high-fluence sample), and demonstrate absence of magnetic in-plane anisotropy. These findings highlight iron implanted strontium titanate as a promising candidate for composite multiferroic material and also for gas sensing applications.     

Effect of cesium salt of tungstophosphoric acid (Cs-TPA) on the properties of sulfonated polyether ether ketone (SPEEK) composite membranes for fuel cell applications

We have prepared composite membranes for fuel cell applications. Cesium salt of tungstophosphoric acid (Cs-TPA) particles was synthesized by aqueous solutions of tungstophosphoric acid and cesium hydroxide and, Cs-TPA particles and sulfonated (polyether ether ketone) (SPEEK) with two sulfonation degrees (DS), 60 and 70%have been used. We examined both the effects of Cs-TPA in SPEEK membranes as functions of sulfonation degrees of SPEEK and the content of Cs-TPA. The performance of the composite membranes was evaluated in terms of water uptake, ion exchange capacity, proton conductivity, chemical stability, hydrolytic stability, thermal stability and methanol permeability. The morphology of the membranes was investigated with SEM micrographs. Increasing sulfonation degree of SPEEK from 60 to 70 caused agglomeration of the Cs-TPA particles. The methanol permeability was reduced to 4.7 × 10⁻⁷ cm²/s for SPEEK (DS: 60%)/Cs-TPA membrane with 10 wt.% Cs-TPA concentration, and acceptable proton conductivity of 1.3 × 10⁻¹ S/cm was achieved at 80 °C under 100% RH. The weight loss at 900 °C increased with the addition of inorganic particles, as expected. The hydrolytic stability of the SPEEK/Cs-TPA based composite membranes was improved with the incorporation of the Cs-TPA particles into the matrix. We also noted that SPEEK60/Cs-TPA composite membranes were hydrolytically more stable than SPEEK70/Cs-TPA composite membranes. On the other hand, Methanol, water vapor, and hydrogen permeability values of SPEEK60 composite membranes were found to be lower than that of Nafion^®.     

Integration into mathematics classrooms of an adaptive and intelligent individualized e-learning environment: Implementation and evaluation of UZWEBMAT

The purpose of this study is to design an adaptive and intelligent individualized e-learning environment based on learning style and expert system named UZWEBMAT and to evaluate its effects on students’ learning of the unit of probability. In the study, initially, learning objects were prepared in three different ways in relation to Visual–Auditory–Kinesthetic (VAK) learning style for each subject of the probability unit. These were appropriate for secondary school mathematics curricula. Then, they were transferred into the digital environment. Each student may follow a different course, and the solution supports s/he will get may also differ highlighting the individual learning. The sample of the study consists of 81 10th grade students from two high schools in Trabzon, Turkey. Qualitative and quantitative data were collected from students to answer research questions. Quantitative data were given as frequency distribution and percentages. Qualitative data were analyzed using qualitative data analysis methods. Results of the study indicated that opinions regarding UZWEBMAT are rather positive. Aiming at individual learning, UZWEBMAT provides the most appropriate environment for students. In addition, UZWEBMAT can be used as well to reinforce traditional classroom education.     

The effect of graphene flake size on the properties of graphene-based polymer composite films

In this work, the role of graphene flake size on the properties of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) composites was studied. Graphene flakes were added to PVDF-HFP using a solution mixing and molding process. By increasing graphene particle size and its concentration in the composites, higher electrical conductivity, in-plane thermal conductivity, and elastic modulus were achieved. Maximum tensile strength was obtained for the composites with average graphene flake size of 2, 5, and 7 μm at graphene concentrations of 10 wt%, 5 wt%, and 20 wt%, respectively. Thick flexible composite films (0.2–0.4 mm) with ultra-high in-plane electrical conductivity (~4500 S/m), in-plane thermal conductivity (~26 W/m/K), and tensile strength (~50 MPa) were obtained for the samples containing the graphene flakes with a larger average particle size of 7 μm. To our knowledge, the first two values are larger than any other values reported in the literature for PVDF-based composites.     

Psychotherapy and the law: The duty to warn.

Suggests that the approach by L. Everstine et al (see record 1980-31031-001) to the process of obtaining the client's informed consent is helpful and will protect both clients and therapists. The standard citation for the Tarasoff v. Regents of the University of California, 17 C.3d 425, 131 Cal Rptr. 14, 551 P.2d 334 (1976) is given. Also mentioned is a more recent case, Thompson v. County of Alameda, 27 Cal 3d 741, 167 Cal Rptr. 70, (July, 1980). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Long‐Term Effects of E‐Advertising: The Influence of Internet Pop‐ups Viewed at a Low Level of Attention in Implicit Memory

Faced with an abundance of advertising messages, Internet users allocate only minimal cognitive resources to advertising. What are the effects of pop‐up ads for a new brand viewed at low‐level attention, and then measured when the Internet users have forgotten having seen them? In the theoretical context of processing fluency and implicit memory, the experiment (n = 398) studied the effects of repeated brief exposure to different types of content (words/image) in pop‐up ads 7 days and 3 months after exposure. The results show the overall positive effects of the pop‐ups, the superiority of the image over words for effects on attitude toward the brand and the purchase intentions; but the words produce more semantic effects than the image.     

Quantum chemical computational studies on bis-thiourea zinc acetate

In this study, quantum chemical calculations of vibrational spectra, Raman spectra, electronic properties (total energy, dipole moment, electronegativity, chemical hardness and softness), Mulliken atomic charges and thermodynamic parameters of bis-thiourea zinc acetate (BTZA) have been performed using Gaussian 09 program. Additionally, nonlinear optical (NLO), conformational, natural bond orbital (NBO) analyses of BTZA have been carried out using the same program. The structural and spectroscopic data of the molecule in the ground state have been calculated using Hartree-Fock (HF) and density functional method (DFT/B3LYP) with the 6-311++G(d,p) basis set. In addition, the molecular frontier orbital energies (HOMO, HOMO-1, LUMO and LUMO+1) of the title compound have been calculated at the HF and B3LYP levels. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. Finally, the calculated results were applied to simulate infrared and Raman spectra of the title compound which showed good agreement with the experimental ones.