Coherence filters and their uses II. One-dimensional realizations

Abstract

In part I of this investigation it was shown that the phenomenon of correlation-induced spectral changes may be used to construct novel types of spectral filter which could modify the spectrum of the source in any desired manner. In the present paper a method of realizing such filters is described and some of their potential applications are discussed.     

Synthesis and Properties of some ε‐Caprolactone‐Based Di‐ and Triblock Polymers by Anionic Polymerization

Block copolymers containing ε‐caprolactone were synthesized. Mechanical properties as a function of chemical composition and domain structure as a function of elongation were studied. Based on previous optimal conditions determination by factorial design of experiments of ε‐caprolactone anionic polymerization, polystyrene‐block‐poly(ε‐caprolactone), polyisoprene‐block‐poly(ε‐caprolactone), polystyrene‐block‐polybutadiene‐block‐poly(ε‐caprolactone) (SBCL), and polystyrene‐block‐polyisoprene‐block‐poly(ε‐caprolactone) (SICL) with different compositions where synthesized, and characterized by GPC and DSC. Both the SICL and SBCL materials are thermoplastic elastomers, from which spin‐cast films were prepared. Their mechanical properties were determined, small angle X‐ray scattering (SAXS) measurements were carried out during straining, and dynamic mechanical analysis (DMA) was performed. All diblock polymers separate into a two‐phase structure, but the melting point of crystalline poly(ε‐caprolactone) domains in the block polymer is higher than in the case of the homopolymer. According to DMA data, some of the SICL and SBCL materials are three‐phase systems, but others are only two‐phase systems. The two‐phase materials show a considerable depression of the composite hard domain glass transition and, consequently, turn out to be very soft. It appears peculiar that the transition from three‐phase to two‐phase material is accomplished by decreasing the soft block length. For the soft material SAXS exhibits a lamellar stack nanoscale structure and several reflections of colloidal crystals. As a function of increasing elongation, the crystal reflections broaden, whereas lamellar stacks rotate as a whole.     

Thermal cycling performances of multilayered yttria-stabilized zirconia/gadolinium zirconate thermal barrier coatings

Gadolinium zirconate (Gd₂Zr₂O₇, GZO) as an advanced thermal barrier coating (TBC) material, has lower thermal conductivity, better phase stability, sintering resistance, and calcium-magnesium-alumino-silicates (CMAS) attack resistance than yttria-stabilized zirconia (YSZ, 6-8 wt%) at temperatures above 1200°C. However, the drawbacks of GZO, such as the low fracture toughness and the formation of deleterious interphases with thermally grown alumina have to be considered for the application as TBC. Using atmospheric plasma spraying (APS) and suspension plasma spraying (SPS), double-layered YSZ/GZO TBCs, and triple-layered YSZ/GZO TBCs were manufactured. In thermal cycling tests, both multilayered TBCs showed a significant longer lifetime than conventional single-layered APS YSZ TBCs. The failure mechanism of TBCs in thermal cycling test was investigated. In addition, the CMAS attack resistance of both TBCs was also investigated in a modified burner rig facility. The triple-layered TBCs had an extremely long lifetime under CMAS attack. The failure mechanism of TBCs under CMAS attack and the CMAS infiltration mechanism were investigated and discussed.     

Processing parameters for selective intermixing of GaAs/AIGaAs quantum wells

Some of the parameters which determine the amount of intermixing of GaAs/AIGaAs quantum wells (QWs) using SiO₂ capping and rapid thermal annealing (RTA) have been studied using photoluminescence (PL) techniques. The degree of intermixing of QWs was found to be larger for thicker SiO₂ capping layers and for shorter distances between the QWs and the oxide-wafer interface. A maximum PL energy difference of 90 meV was observed between the region covered by a 1.3 μm thick oxide layer and the non-oxide region in a wafer that was annealed at 1100° C for 15 s.     

Hypnosis training in APA- and non-APA-approved clinical/counseling doctoral programs.

Assessed the status of and attitudes toward hypnosis training in 186 American Psychological Association (APA)-approved and nonapproved doctoral programs. 53% of the departments returned questionnaires within the allotted time period. Results indicate that 30% of the APA-approved and 39% of the non-APA-approved programs offer either a full or partial course in hypnosis. Approximately 60% of the programs in both groups either offer some type of academic course or allow students the opportunity to enhance their previously learned hypnosis skills through practicum courses. Respondent attitudes toward hypnosis were generally positive. (4 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optical observation of growth and melting dynamics of3He-4He mixture crystals

Crystals grown from 2.1% and 9.3% solutions of³ He in⁴He were observed in a cryostat with optical access from two orthogonal directions (above and from the side). Video films of dynamic processes were recorded at temperatures between 0.5K and 1.8K. Facetted melting of crystals (in contrast with rounded melting which is the general case) was observed below 0.75K. This is in accordance with previous experiments which showed a higher³He concentration along the edges of the crystal. We also recorded morphological growth instabilities of the 9.3% b.c.c. crystals. In the temperature region below about 0.9K where the latent heat is negative no dendritic growth was observed, which we interpret as resulting from opposing effects of temperature and concentration gradients.     

A Cube Model for Competency Development: Implications for Psychology Educators and Regulators.

This article provides a conceptual framework for training in professional psychology focused on the construct of competency. The authors present a 3-dimensional competency model delineating the domains of knowledge, skills, attitudes, and values that serve as the foundation required of all psychologists, the domains of functional competencies that broadly define what psychologists do, and the stages of professional development from doctoral education to lifelong learning through continuing education. The goal in presenting this model is to provide a conceptual frame of reference for those responsible for psychology education, credentialing, and regulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nitridation of hafnium oxide by reactive sputtering

Hafnium oxide films were RF sputtered from HfO₂ target in Ar/O₂ or Ar/N₂ ambient on silicon substrates. The composition of the deposited films was analyzed by X-ray photoelectron spectroscopy (XPS). For samples sputtered in Ar/N₂, it was observed that nitrogen was incorporated in the bulk of hafnium oxide films in the form of HfON, and SiON layer was formed at the silicon-insulator interface. After annealing the hafnium oxide films at 600-700 °C, MOS structures were fabricated and used for electrical characterization. The effects of nitridation of hafnium oxide on both the capacitance-voltage and current-voltage characteristics of the MOS capacitors were discussed.     

Interactive design and optimization of flight-vehicle lifting surface structures

A computerized procedure for the design and optimization of flight vehicle structures employing interactive graphics is described. The procedure represents a subsystem of the multi-disciplinary Interactive Structural Sizing and Analysis System (ISSAS), currently being employed at IAI. The paper describes three interactive modules that deal with the primary structural layout, design, finite element modeling and reduction of analytic data for flight vehicle lifting surface structures. The procedure described herein represents a sizable saving in elapsed time and man-hours per design iteration, relative to conventional methods, and provides for the design of superior quality structure in a shorter period of time and at lower cost.