Uniform performance of high-efficiency room-temperature GaInAsSb/GaSb photodiodes for 1.75 < lambda < 2.2 mum.
A group of 126 experimental, packaged, backilluminated, 1.75-2.2-microm wavelength, GaInAsSb mesa (~85-microm diameter) photodetectors have been assembled and evaluated. Average room-temperature properties were peak quantum efficiency, 86%; zero-bias capacitance, 3.9 pF; dark current at -0.5-V bias, 7.4 microA.
Room-temperature GaInAsSb/AlGaAsSb DH injection lasers at 2.2 μm
Double-heterostructure lasers based on the GaInAsSb/AlGaAsSb system have been prepared by liquid-phase epitaxy and operated in the 2.2 μm-wavelength region. Room-temperature, pulsed threshold current densities of 6 kA/cm2 and characteristic temperatures of T 0= 85 K have been obtained.
Pig Vocalizations Under Selected Husbandry Practices
Acoustical characteristics of vocalizations of sows, piglets, and nursery pigs under selected husbandry practices were analyzed with a digital signal processing system. The duration (D) and major energy-resonance frequency (P) for each call were determined as follows: a) processing of piglets (D = 0.81 s and f* = 3 700 Hz); b) food anticipation of breeding-gest ation sows (2.50 s and 3 000 Hz); c) isolation of piglet (0.34 s and 500, 3 500 Hz); d) startling of nursery pigs (0.29 s and 900 Hz); e) sows in heat (3.07 s and 1 375 Hz); f) farrowing (0.10 s and 3 000 Hz); g) sow nursing (0.15 s and 1 000 Hz); and h) mate greeting of sow (0.13 s and 1 000 Hz). Calls a) to d) are responses to human generated stressors, and calls e) through h) responses to social and physiological states of the pigs. Thus, vocalizations can be segmented for different pig production situations.