Design and performance of a complex-coupled DFB laser with sampled grating

A complex-coupled DFB laser with sampled grating has been designed and fabricated. The method uses the + 1 st order reflection of the sampled grating for laser single-mode operation. The typical threshold current of the sampled grating based DFB laser is 25 mA, and the optical output is about 10 mW at the injected current of 100 mA. The lasing wavelength of the device is 1.5385μm, which is the +1 st order wavelength of the sampled grating.

1.3 mu m InGaAsP/InP strained layer multi-quantum-well complex-coupled distributed feedback laser

1.3 mu m strained-layer multi-quantum wells complex-coupled distributed feedback lasers with a wide temperature range of 20 to 100 degrees C are reported. The low threshold current of 10mA and high single-facet slope efficiency of 0.3mW/mA were obtained for an as cleaved device. The single mode yield was as high as 80%.

Epitaxial growth of SiC on complex substrates

Epitaxial growth of SiC on complex substrates was carried out at substrate temperature from 1200 degreesC to 1400 degreesC. Three kinds of new complex substrates, c-plane sapphire, AlN/sapphire, and GaN/AlN/sapphire, were used in this study. We obtained a growth rate in the range of 1-6 mum/h. Thick (6 mum) SIC epitaxial layers with no cracks were successfully obtained on AlN/sapphire and GaN/AlN/sapphire substrates. X-ray diffraction patterns have confirmed that single-crystal SiC was obtained on these complex substrates. Analysis of optical transmission spectra of the SIC grown on sapphire substrates shows the lowest-energy gap near 2.2 eV, which is the value for cubic SiC. The undoped SIC showed n-type electrical conductivity. (C) 2001 Elsevier Science B.V. All rights reserved.

A modified criterion for shear band formation in bulk metallic glass under complex stress states

A new criterion for shear band formation in metallic glasses is proposed based on the shear plane criterion proposed by Packard and Schuh [1]. This modified shear plane (MSP) criterion suggests that a shear band is not initiated randomly throughout the entire material under stress but is initiated at the physical boundaries or defects and at locations where the highest normal stress modified maximum shear stress occurs. Moreover, the same as in the shear plan criterion, the shear stress all over the shear band should exceed the shear yield strength of the material. For a complete shear band to form, both requirements need to be fulfilled. The shear yield strength of the material is represented by the shear stress of the point at which the shear band stops. The new criterion agrees very well with experimental results in both the determination of the shear yield strength and the shear band path. (C) 2010 Elsevier B.V. All rights reserved.

Probability of Sediment Incipient Motion Under Complex Flows

Presented in this paper is a mathematical model to calculate the probability of the sediment incipient motion, in which the effects of the fluctuating pressure and the seepage are considered. The instantaneous bed shear velocity and the pressure gradient on the bed downstream of the backward-facing step flow are obtained according to the PIV measurements. It is found that the instantaneous pressure gradient on the bed obeys normal distribution. The probability of the sediment incipient motion on the bed downstream of the backward-facing step flow is given by the mathematical model. The predicted results agree well with the experiment in the region downstream of the reattachment point while a large discrepancy between the theory and experiment is seen in the region near the reattachment point. The possible reasons for this discrepancy are discussed.

HIRFL-CSR complex

The construction and commissioning of HIRFL-CSR were finished in 2007. From 2000 to 2005 the subsystem and key devices of CSR were successfully fabricated, such as magnet, power supply, UHV system, e-cooler, electric-static deflector with the septum of 0.1 mm, and the fast-pulse kicker with the rise time of 150 ns. After that the CSR commissioning activities were performed in 2006 and 2007, including the accumulation of those heavy ions of C, Ar, Kr and Xe by the combination of stripping injection (STI) or multiple multi-turn injection (MMI) and e-cooling with a hollow e-beam, wide energy-range synchrotron ramping by changing the RF harmonic-number at mid-energy, the beam stacking in the experimental ring CSRe, the RIBs mass-measurement with the isochronous-mode in CSRe by using the time-of-flight method, and the ion beam slow-extraction from CSRm.

Slow cross-symmetry phase relaxation in complex collisions

We discuss the effect of slow phase relaxation and the spin off-diagonal S-matrix correlations on the cross-section energy oscillations and the time evolution of the highly excited intermediate systems formed in complex collisions. Such deformed intermediate complexes with strongly overlapping resonances can be formed in heavy-ion collisions, bimolecular chemical reactions, and atomic cluster collisions. The effects of quasiperiodic energy dependence of the cross sections, coherent rotation of the hyperdeformed similar or equal to(3 : 1) intermediate complex, Schrodinger cat states, and quantum-classical transition are studied for Mg-24 + Si-28 heavy-ion scattering.