1,722,961 research outputs found
mathewsii
No full textLoeseliastrum matthewsii (A. Gray) S. TimbrookDesert calicoLangloisia mathewsiiJoshua Tree National Monument. Covington Flat Canyon.4200 fee
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Raman amplifier for ultrashort soliton transmission
No full textWe consider the choice of pump wavelength for a Raman amplified picosecond soliton transmission system and demonstrate transmission of 800 fs solitons over 22 km using a 1535 nm pump source
Passive harmonically modelocked fibre soliton laser with repetition rate above 2 GHz
No full textWe present a study of a passive harmonically modelocked subpicosecond soliton fibre laser which operates with a repetition rate above 2 GHz. Modelocking of the laser is achieved by the combined action of a multi-quantum well (MQW) saturable absorber and a nonlinear amplifying loop mirror. In this configuration the MQW sample acts not only as a saturable absorber but also acts as a passive phase modulator which is capable of stabilizing the pulse repetition rate. A simple model describing this process in terms of excited free carriers in the MQW is presented and is used to derive an expression for the time jitter of the laser which gives good agreement with experimentally observed values
Soliton fibre laser with hybrid saturable absorber
No full textWe present an experimental study of a picosecond fiber soliton laser in which mode-locking is achieved by the combined action of MQW saturable absorber and nonlinear amplifying loop mirror (NALM). In this configuration a MQW sample acts not only as a saturable absorber but also as a passive phase modulator while the inclusion of NALM ensure fixed energy of the generated pulses. The laser stably operates at repetition rate of 250 MHz with timing jitter below 10 ps
Two gigahertz soliton fibre laser modelocked with hybrid saturable absorber
No full textA subpicosecond fibre soliton laser passively modelocked by the combined action of a multi-quantum well saturable absorber and nonlinear amplifying loop mirror is shown to operate with a stable repetition rate of over 2GHz
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