Introduction: Building on the expanding cross cultural interest in FACES, the Spanish version of the Family Adaptability and Cohesion Evaluation Scale (FACES IV), aimed at the assessment of the dimensions of cohesion and flexibility of the Circumplex Model, was validated following the author's guidelines. Method: The sample was composed by 665 college students. Besides, FACES II was also used and family communication, satisfaction, stress and strengths were also measured. Results: The results supported its psychometric adequacy. Construct validity, concurrent and discriminant validity of all the scales were confirmed, maintaining the original structure of the instrument, with 6 scales, 4 Unbalanced scales (Disengaged, Enmeshed, Rigid, and Chaotic), and two Balanced scales (Cohesion and Flexibility). Additionally, the ratio scores confirmed the curvilinearity of the model. Conclusion: All the results supported the adequacy of the Spanish version, which is also promising for use in educational settings, in counseling and in research. Findings with the Spanish version of FACES IV are similar to findings in the United States and other countries.

The aim of this study was to obtain a culturally adapted Spanish version of the American Family Adaptability and Cohesion Evaluation Scale (FACES IV). For this purpose, rigorous procedures were used in the retro-translation process and in the subsequent empirical study. The sampling consisted of 455 university students and a balanced scale of 13 items (α = .87) was obtained; a scale that can be used independently. Moreover, the study was rounded off with a 6-factor model that includes 2 central scales—cohesion and adaptability—and 4 extreme scales—chaotic, rigid, disengaged, and enmeshed—each one with 4 items. All the scales proved to have good psychometric qualities and suitable convergent, concurrent, and content validity, yet it will be necessary to go more deeply into the rigid scale. The construct validity was supported by a confirmatory factorial analysis with sound fit indexes (root mean square error of approximation [RMSEA] = 0.046, normed fit index [NFI] = 0.94, the comparative fit index [CFI] = 0.97, and the goodness-of-fit index [GFI] = 0.92). In its Spanish version, FACES IV is a useful instrument for family assessment, although further studies need to be carried out so as to confirm the results obtained.

Section Headings. Preface. Introduction and explanatory notes. Framework type data sheets (arranged by 3-letter code in alphabetical order). Appendices. Isotypic material index.

An experimental X-ray powder diffraction pattern was produced and analyzed for alpha-polymorphic tegafur, also called Ftorafur (an antineoplastic agent). The indexed data matched the powder patterns in the ICDD PDF-4/Organics database calculated from the reported single-crystal X-ray diffraction data in the Cambridge Structural Database. Alpha tegafur has a triclinic crystal system, with reduced cell parameters of a=16.720(6) Å, b=9.021(5) Å, c=5.995(3) Å, α=93.66(4)°, β=93.15(8)°, γ=100.14(4)°. There are four formula units contained in one unit cell. The cell volume and space group were determined to be 886.27 Å3 and P-1, respectively.

Semi-insulating multiple quantum well photorefractive devices using GaAs/Al0.29Ga0.71As with an electric field applied perpendicular to the layers are demonstrated. Semi-insulating behavior is obtained by doping with Cr(1016/cm3) during epitaxial growth of the material. Diffraction efficiencies as high as 3% with an applied voltage of 20 V and microsecond response times are obtained in a 2 μm thick device. These devices are of importance for implementation of fast and sensitive two-dimensional optical information processing systems at wavelengths compatible with current diode lasers without the spatial-bandwidth limitations of thick photorefractive materials.

Single-pulse and cw measurements of the response of a semi-insulating CdZnTe/ZnTe multiple-quantum-well photorefractive device are presented. In single-pulse experiments, photodiffractive (absorption) gratings have been written with less than 1.8-microJ/cm(2) incident fluence, and a diffraction efficiency of 1.1% is obtained from the 1.56-microm active layer of the device. With an optimized structure, the ultimate response time of the device can be below 100 ps. In cw measurements a maximum diffraction efficiency of 1.35% is obtained.

We have studied the effect of barrier design on the grating period dependence of the diffraction efficiency in semi-insulating GaAs/AlGaAs and CdZnTe/ZnTe multiple quantum well photorefractive devices in the geometry with the applied field perpendicular to the quantum wells. In GaAs/ AlGaAs devices, lowering of the barrier height by reduction of Al concentration from 40% to 30% and reduction of barrier thickness from 100 Å to 35 Å increases the diffraction efficiency by 5 orders of magnitude. This is due to the reduction in carrier sweepout time from the quantum wells reducing the lateral diffusion of carriers in the wells. In an optimized structure, a diffraction efficiency of 3% at 852 nm from a 2 pm thick sample is obtained by application of 20 V. We will discuss the relevant parameters in the design of a photorefractive multiple quantum well device. As an application, the performance of a joint transform correlator based on a multiple quantum well photorefractive device and diode lasers will be discussed.

We describe the video-rate operation of a compact (30 × 30 × 10 cm) joint transform optical image correlator using two cw diode lasers and a semi-insulating GaAs/AlGaAs multiple-quantum-well photorefractive device as the erasable holographic element. The video images of the objects to be correlated are introduced to the system through a liquid crystal spatial light modulator (SLM) containing 320 × 220 pixels, and the resultant correlation is read out with a CCD camera. With only 1 mW incident write power at 830 nm, the response time of the photorefractive device is sub-microsecond, presenting the possibility of more than 10 6 correlations per second in a compact system. Furthermore, the small interaction length of the multiple-quantum-well device (2 μm) removes the spatial-bandwidth limitations of correlators based on thick photorefractive materials operating in the Bragg regime. We will discuss the performance of this system for pattern and character recognition.

Although the photorefractive sensitivity of the semiconductors is many orders of magnitude larger than the oxides, their small Pockels electro-optic coefficient has been a serious drawback. By taking advantage of the quadratic effects near the band-edge, nonlinearity and sensitivity of semiconductor photorefractivcs can be dramatically improved. Recently, two-beam-coupling gain coefficients of 16.3 cm−1 in GaAs [1] and 26.0 cm−1 in InP [2] have been reported near the band-edge. Quantum confinement of excitons in multiple quantum wells (MQWs) provides an additional enhancement of the resonant electro-optic nonlinearities. We have recently demonstrated how enhanced photorefractive sensitivity can be obtained in semi-insulting MQW devices [3]. These devices were made semi-insulting through ion-implantation to provide sufficient density of traps for the photorefractive process as well as relieving the need for any pixelation.

We report the first study of the room-temperature electroabsorption effects in CdZnTe/ZnTe multiple quantum well structures which exhibit sharp excitonic absorption peaks. The magnitude of the Franz Keldysh and quantum-confined Stark Effects are found to be comparable to those of III-V semiconductors. With optimized structures we expect II-VI semiconductors to be important components for information processing in the visible spectrum.

We present results on the operation of a high sensitivity semi-insulating multiple quantum well device for optical image processing. This device operates in the visible spectrum using II-VI CdZnTe/ZnTe multiple quantum well structures. Incident light creates charge carriers that screen an applied ac electric field modulating the absorption and refractive index of the structure through the quantum confined Stark effect. In this way, an incident intensity pattern is recorded as an absorption and refractive index variation. The semi-insulating nature of the material eliminates the need for pixelation. In a wave-mixing experiment, a peak diffraction efficiency of 0.25% was observed from 2.25 μm active layer of the device. Two-beam-coupling gain coefficients of ∼500 cm−1 at wavelengths longer than the exciton absorption peak should be possible.

Optically pumped lasing has been observed up to 100 K in a Cd 0.2 Zn 0.8 Te ZnTe superlattice grown on a GaAs Si substrate. At 100 K, rapid degradation of the lasing signal is seen. This result is inferior to that previously reported for a similar structure grown on a GaAs bulk substrate, for which room-temperature lasing was seen with no degradation. X-ray rocking curve and morphology measurements suggest that the II–VI epilayer has limited ability to heal the extra defects that are present when a GaAs Si , rather than a bulk GaAs, substrate is used.

We use semi-insulating multiple quantum wells to combine the holographic properties of the photorefractive effect with the large resonant optical nonlinearities of quantum-confined excitons. GaAs–AlGaAs multiple-quantum-well structures are made semi-insulating by proton implantation. The implant damage produces defects that are available to trap and store charge during transient holographic recording by means of coherent excitation. The advantages of charge storage and resonant optical nonlinearity combine to produce new optical devices with large sensitivities. The potential use of these devices for image processing is demonstrated by using the Franz–Keldysh effect in four-wave mixing at wavelengths near 830 nm.

Defect levels in semi-insulating GaAs and InP are investigated by deep level photodiffractive spectroscopy. Temperature-dependent four-wave mixing based both on photochromic and photorefractive effects permits a determination of the energy levels within the semiconductor band gap. This optical technique eliminates difficulties encountered with high-resistivity material using conventional electrical measurements.

Current oscillations arising from voltage-controlled negative differential resistivity are observed in optically pumped semi-insulating InP at low temperature. The presence of high-field domains sweeping through the sample are detected using photorefractive four-wave mixing. Direct evidence of the role of defects in these current oscillations is presented using deep-level photodiffractive spectroscopy. A deep hole trap with an energy Ev +85 meV is observed. The current oscillations occur only when this defect level is partially occupied.

We have performed photodiffractive four-wave mixing in semi-insulating multiple GaAs/AlGaAs quantum wells at a wavelength of 0.83 microm. The quantum wells were made semi-insulating by proton implantation, which introduces defects that are available to trap and store charge during holographic recording. The experiments demonstrate how photodiffractive behavior using the large resonant nonlinearities of quantum-confined excitons yields highly sensitive material for optical image processing. When pump powers of 1 mW/cm(2) are used, the measured sensitivity is 2 orders of magnitude greater than that of bulk, nonresonant photorefractive semiconductors.

We report here for the first time the demonstration of self-pumped phase conjugation in photorefractive semiconductors using 1.32 μm light. Using an ac field technique to enhance the gain coefficient in InP:Fe and a single input pump beam, phase conjugate reflectivities of 11% were measured using an input beam intensity of less than 1 mW/mm2. These results open up many possibilities for using photorefractive semiconductors in applications with low-power infrared diode lasers.