The AlGaAs single-mode stability

Single-mode spectral behavior with aging in constricted double heterojunction (CDH) lasers was studied. The CDH lasers demonstrated excellent reliability ( or = 1 million years extrapolated room-temperature MTTF) and single-mode operation after 10,000 hours of 70 C aging. The deleterious effects of laser-fiber coupling on the spectra of the diodes were eliminated through the use of wedge-shaped fibers. A novel high-power large optical cavity (LOC)-type laser was developed: the terraced-heterostructure (TH)-LOC laser, which provides the highest power into a single-mode (i.e., 50 mW CW) ever reported

Studies of single-mode injection lasers and of quaternary materials. Volume 1: Single-mode constricted double-heterojunction AlGaAs diode lasers

Constricted double-heterojunction (CDH) lasers are presented as the class of single-mode nonplanar-substrate devices for which the lasing cavity is on the least resistive electrical path between the contact and the substrate. Various types of CDH structures are considered under three general topics: liquid-phase epitaxy over channeled substrates, lateral mode control, and current control in nonplanar-substrate devices. Ridge-guide CDH lasers have positive-index lateral-mode confinement and provide: single-mode CW operation to 7 mW/facet at room temperature and to 3 mW/facet at 150 C; light-current characteristics with second-harmonic distortion as low as -57 dB below the fundamental level; threshold-current temperature coefficients, as high as 375 C (pulsed) and 310 C (CW); constant external differential quantum efficiency to 100 C; and lasing operation to 170 C CW and 280 C pulsed. Semileakyguide CDH lasers have an asymmetric leaky cavity for lateral-mode confinement and provide single-mode operation to 15 to 20 mW/facet CW and to 50 mW/facet at 50% duty cycle. Modulation characteristics and preliminary reliability data are discussed

Phase Synchronization and Polarization Ordering of Globally-Coupled Oscillators

We introduce a prototype model for globally-coupled oscillators in which each element is given an oscillation frequency and a preferential oscillation direction (polarization), both randomly distributed. We found two collective transitions: to phase synchronization and to polarization ordering. Introducing a global-phase and a polarization order parameters, we show that the transition to global-phase synchrony is found when the coupling overcomes a critical value and that polarization order enhancement can not take place before global-phase synchrony. We develop a self-consistent theory to determine both order parameters in good agreement with numerical results

Meat Product Reformulation: Nutritional Benefits and Effects on Human Health

This chapter aims to present the current state of the art in the field of meat product reformulation with respect to issues concerning the nutritional improvement and overall health benefits of such products. Our research team has recently finalised a national research project concerning this topic, and we feel that other food scientists could benefit from the theoretical and practical knowledge gathered during this time. The chapter will be divided into four subchapters. The first subsection will present the main targets of meat reformulation, such as lipid or protein profile modification, the use of bioactive compounds as additives, etc. The second subsection will discuss the bioavailability and bioaccessibility of carotenoids, phenolic compounds and other bioactive compounds, presenting these parameters from a nutraceutical perspective. The last subsections will include reported consumer attitudes. In this work, we will present data that could aid scientists in the field of food science to better grasp notions concerning consumer benefit, such as bioavailability, not only of a specific bioactive compound but also as part of a complex food matrix

Evidence of Low-Temperature Superparamagnetism in Mn3O_{3}O_{4}$ Nanoparticle Ensembles

Please refer to the abstract within the main body of the paper

Vacancy trapping and annealing in noble-metal films grown at low temperature

doi:10.1063/1.1527988We have used synchrotron x-ray diffraction to study the homoepitaxial growth on Cu(001), Ag(001), and Ag(111), at temperatures between 300 and 65 K. The growth on all of these surfaces exhibits a consistent trend towards a large compressive strain that is attributed to the incorporation of vacancies into the growing film below 160 K. In each case, the vacancy concentration is ∼ 2% at 110 K and we have measured the temperature dependence for incorporation on the (001) surfaces as well as the annealing behavior for Cu(001). These results, which suggest new kinetic mechanisms, have important implications for understanding epitaxial crystal growth.Support is acknowledged from the NSF under Contract Nos. ~P.W.S! DMR-9202528 and ~P.F.M!, ~C.E.B! DMR-9623827, MISCON under DOE Grant No. DE-FG02-90ER45427, and the University of Missouri Research Board. The SUNY X3 beam line is supported by the DOE, under Contract No. DE-FG02-86ER45231 and the NSLS is supported by the DOE, Division of Material Sciences and Division of Chemical Sciences. The Advanced Photon Source is supported by DOE Contract No. W-31-109-Eng-38, and the mCAT beam line is supported through the Ames Laboratory Contract No. DOE W-7405-Eng-82