A Ti:Al2O3 master-oscillator/power-amplifiersystem

The authors have constructed a multistage Ti:Al₂O₃ master-oscillator/power-amplifier system which generates 115-ns, 0.38-J pulses at 800 nm. The system is tunable from 760 to 825 nm and has a repetition rate of 10 Hz. Measurements of the output pulse demonstrate near-diffraction-limited performance and a Fourier-transform-limited bandwidth of ~4 MHz     

Growth, spectroscopy, and lasing of titanium-doped sapphire

The growth, spectroscopy, and lasing of titanium-doped sapphire are discussed. Particular attention is given to the problems of achieving high-quality laser material and to the identification and elimination of defects that currently limit Ti:Al2O3laser performance.     

Chaotic Expansion of Elements of the Universal Enveloping Algebra of a Lie Algebra Associated with a Quantum Stochastic Calculus

The functional Ito formula, in the form df() = f( + d ) –f(),is formulated and proved in the context of a Lie algebra L associatedwith a quantum (non-commutative) stochastic calculus. Here fis an element of the universal enveloping algebra U of L, andf() + d() – f() is given a meaning using the coproductstructure of U even though the individual terms of this expressionhave no meaning. The Ito formula is equivalent to a chaoticexpansion formula for f() which is found explicitly. 1991 MathematicsSubject Classification: primary 81S25; secondary 60H05; tertiary18B25.     

Adapted packet speech interpolation

Adapted packet speech interpolation (APSI) is presented as an evolution of digital speech interpolation (DSI) techniques. The inherent overload penalties of DSI are mitigated by the use of an overload strategy which distributes the penalties uniformly across all active speech sources. A novel use of linear delta modulation (LDM) allows the system to re-encode the input sources at various rates depending upon the total offered load to the system. The subjective performance of hardware is discussed. Two models of silence and talk-spurt behaviour (called activity) of speech are presented: an analytic model for single speakers obtained by the application of renewal theory, and a simulation model obtained from the analytic model.     

Appropriateness and effectiveness of communication channels in competent interpersonal communication

We examined perceived appropriateness and effectiveness of six communication channels (face-to-face, telephone, voice mail, electronic mail, letter, fax) used in relation to interpersonal communication motives (inclusion, affection, control relaxation, escape, pleasure) in other-directed and self-directed need-fulfillment situations. In Study 1, respondents selected the channel they thought would best communicate standard messages and rated it on effectiveness and appropriateness. In Study 2, respondents rated the effectiveness and appropriateness of all six communication channels by considering scenarios that reflected the two need-fulfillment directions of all six motives. Analyses revealed significant main effects for direction, channel, and motive, and significant interaction effects.