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Pumped by a Ti:sapphire laser, a passively Q-switched laser oscillation from an unprocessed Nd:LaB3O6 cleavage microchip with a Cr4+:YAG saturable absorber has been demonstrated. The influence of the transmission of the output coupler on the pulse width and repetition rate at various absorbed pump powers has been investigated. A pulse with 2.8 μJ energy, 2.2 ns duration, and 29 kHz repetition rate at 1060 nm was obtained at the absorbed pump power of 1.25 W and output coupler transmission of 3.2%, which results in 1.25 kW peak power. The polarization and spectral properties of laser radiation were measured. [ABSTRACT FROM AUTHOR]

The improvement of the laser performances of an unprocessed 5.6 at. % Nd3+:LaB3O6 cleavage microchip has been reported. Pumped by a Ti:sapphire laser at 871 nm, quasi-cw output laser power up to 395 mW around 1060 nm wavelength with slope efficiency near 52% has been obtained in an end-pumped plano-plano resonator. The influence of the ratio between the cavity mode and pump beam area on the laser performances and laser spectra at various output powers has been investigated. The experimental results have shown that the cleavage technique can become a practical and effective method to obtain the microchip laser medium easily and directly. [ABSTRACT FROM AUTHOR]

Investigates some of the properties of strained-layer quantum-well heterostructure (SL-QWH) current injection lasers to evaluate the potential of the strained-layer lasers. Cross section of SL-QWH laser grown by molecular beam epitaxy; Room temperature emission spectra for SL-QWH laser; Degradation of a SL-QWH laser during 1000 h of operation.

Studies the growth and characterization of lattice-matched calcium compound growth in gallium arsenide substrates. Application of lattice-matched insulators on semiconductors; Details on the experiment; Discussion on the results of the study.

Objectives: To determine bone morphogenetic proteins (BMPs) and Dickkopf homologue-1 (Dkk-1) levels in ankylosing spondylitis (AS).Method: Serum BMPs and Dkk-1 were measured in 72 AS patients and 30 healthy controls. For AS patients, we recorded the demographic data, disease activity, functional index, and global assessment with questionnaires, and image changes with roentgenography. We also measured human leucocyte antigen-B27 and systemic inflammatory reactants.Results: BMPs were higher but Dkk-1 was significantly lower in AS patients than in controls. Dkk-1 was higher in AS patients who received non-steroidal anti-inflammatory drugs (NSAIDs) regularly in the past year (p = 0.001). Serum BMP-7 level and the BMP-7/Dkk-1 ratio correlated significantly with sacroiliitis severity, Bath Ankylosing Spondylitis Radiology Index (BASRI)-total, modified Stoke Ankylosing Spondylitis Spinal Score, and disease duration. There were also significant positive correlations among serum levels of BMP-2, -4, and -6, BASRI-total, and disease duration (p < 0.05). However, BMP-2/Dkk-1 was only significantly correlated with disease duration. The calculated area under the standard receiver operating characteristics curve suggested that BMP-2/Dkk-1 and serum BMP-2 are good indicators to predict disease activity, functional index, and patient global assessment in AS patients.Conclusion: BMPs and BMPs/Dkk-1 were significantly correlated with disease activity, and radiological and functional indices in AS patients. Dkk-1 was lower in AS patients than in controls. Among AS patients, Dkk-1 was higher in those taking NSAIDs regularly. BMP or Dkk-1 may be taken as a biomarker for disease severity or a treatment outcome predictor in AS, but this needs further study. [ABSTRACT FROM AUTHOR]

Two novel red phosphors KBaEu(XO4)3 (X = Mo, W) have been synthesized by high-temperature solid-state reactions and the crystal structures were determined for the first time. Single-crystal X-ray diffraction data reveal that their space groups are C2/c. The crystalline structure is constituted of K/BaO8 distorted square antiprisms and distorted EuO8 polyhedra which form chains lying along the c-axis and two kinds of distorted XO4 tetrahedra. This high disorder of K/Ba which might lower the crystal field symmetry around Eu3+ results in the high purity of red emission around 615 nm originating from 5D0→7F2 transition under near-ultraviolet (NUV) excitation. With increasing temperature, the luminescence of KBaEu(XO4)3 (X = Mo, W) phosphors decreases almost linearly with subtle alteration for the CIE coordinate. As the temperature reaches 550 K, the red emission intensity decreases to 37.3% and 50.7% of that at 300 K for KBaEu(MoO4)3 and KBaEu(WO4)3, respectively. The analysis of the decay curves of the 5D0→7F2 emission at variable temperatures indicates the weak cross relaxation and non-radiative energy transfer between Eu3+ ions. These results demonstrate that the investigated phosphors are attractive for application in high power NUV excited white LEDs. [ABSTRACT FROM AUTHOR]

Burrowing is an energetically costly form of locomotion that has evolved multiple times in mammals. Burrowing performance is associated with varying degrees of morphological specialization and is also affected by the characteristics of the substrate that animals burrow in. Moles (Talpidae) are well known for their specialized forelimbs and extreme dedication to life underground. In this study, we investigated how soil compactness affects burrowing performance in two sympatric mole species, eastern moles ( Scalopus aquaticus) and hairy-tailed moles ( Parascalops breweri). We measured burrowing speed, the amount of soil moved, rate of soil transport, tunnel length, activity level and the tendency to burrow over long distances, and tested how these variables changed in response to loose, intermediate and compact soils. We found that increasing soil compactness impedes tunneling performance as evidenced by reduced burrowing speed, increased soil transport, shorter tunnels, shorter activity time and less time spent burrowing continuously. Eastern moles built longer tunnels than hairy-tailed moles as soil compactness increased. This difference is linked to burrowing for longer times and distances, not higher burrowing speeds or rates of soil transport. Differences in performance between the two species may be associated with differences in the structure and extent of their burrow systems or the morphology of their forelimbs. They may also reflect preferences for loose (hairy-tailed moles) or compact soils (eastern moles). [ABSTRACT FROM AUTHOR]

Presents a study which focused on copper spin orientation in titanium(barium strontium)praseodymium copper[sub2]oxygen[sub7]. Methods; Results; Discussion.

Analyzes the growth of single crystals of the superconductor YBa[sub2]Cu[sub3]O[suby] from a mixture of solid phase YBa[sub2]Cu[sub3]O[suby] and liquid phase silver. Details of the process involved in growing high J[subc] superconducting yttrium (Y)-123 crystals from a mixture of stoichiometric Y-123 and Ag[sub2]; Description of stoichiometric Y-123 powder; Comparison between single and cube-like crystals; Effect of the addition of Ag[sub2]O on the stoichiometric Y-123 powder.

Presents a study which examined heteroepitaxial growth of zinc selenide (ZnSe) on a gallium arsenide/silicon (GaAs/Si) substrate. Examination of the crystallinity of ZnSe/GaAs/Si; Relative relationship of thermal mismatch and lattice mismatch of ZnSe to GaAs; Conclusion.

Presents information on a study which discussed the growth of zinc selenide (ZnSe) epitaxial layers on (111) silicon (Si) substrates by low-pressure metalorganic chemical vapor deposition. Measurement of the electrical properties of the ZnSe epilayers; Investigation of the surface morphology and cross section of the ZnSe layers by scanning electron microscopy; Procedure undergone by the Si substrate prior to growth.

Presents a study which examined the relationship of the performance of a double-heterostructure (DH) laser with various polishing techniques used for gallium arsenide (GaAs) substrates preparation. Description of the process of polishing; Fabrication of broad-area laser diodes; Results for DH lasers with GaAs active regions.