Studies of (GaAI)As injection lasers operating with an optical fiber resonator

The characteristics of an optical fiber external resonator in conjunction with (GaAl)As stripe geometry lasers are described. We have observed a 6–10% reduction in the threshold current and have obtained 150 ps pulses at gigahertz repetition rates. The fiber resonator has also been used to quench self‐pulsations in a (GaAl)As injection laser. In order to explain many of our results we have used a model that uses the conventional semiconductor rate equations modified by the addition of saturable electron traps and the effects of the external cavity. Our results predict many of the self‐locking effects observed in injection lasers operating in an external cavity. Furthermore, the degree of self‐locking will be a strong function of the external cavity length and the density of saturable absorbers

Asymptotic analysis of first passage time in complex networks

The first passage time (FPT) distribution for random walk in complex networks is calculated through an asymptotic analysis. For network with size $N$ and short relaxation time $\tau\ll N$, the computed mean first passage time (MFPT), which is inverse of the decay rate of FPT distribution, is inversely proportional to the degree of the destination. These results are verified numerically for the paradigmatic networks with excellent agreement. We show that the range of validity of the analytical results covers networks that have short relaxation time and high mean degree, which turn out to be valid to many real networks.Comment: 6 pages, 4 figures, 1 tabl

Beam breakup instability in an annular electron beam

It is shown that an annular electron beam may carry six times as much current as a pencil beam for the same beam breakup (BBU) growth. This finding suggests that the rf magnetic field of the breakup mode is far more important than the rf electric field in the excitation of BBU. A proof‐of‐principle experiment is suggested, and the implications explored.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71057/2/JAPIAU-74-9-5877-1.pd

Sequence of phase formation in planar metal-Si reaction couples

A correlation is found between the sequence of phase formation in thin-film metal-Si interactions and the bulk equilibrium phase diagram. After formation of the first silicide phase, which generally follows the rule proposed by Walser and Bené, the next phase formed at the interface between the first phase and the remaining element (Si or metal) is the nearest congruently melting compound richer in the unreacted element. If the compounds between the first phase and the remaining element are all noncongruently melting compounds (such as peritectic or peritectoid phases), the next phase formed is that with the smallest temperature difference between the liquidus curve and the peritectic (or peritectoid) point

Effects of a series resistor on electron emission from a field emitter

Universal curves are constructed that provide an immediate determination of the effect of a series resistor on the electron emission from a field emitter. These curves are applicable to both the low current and high current regime. The effects of space charge and of the series resistor are apparent from these curves, which are applicable to a large class of materials. An example is given to illustrate their use. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70468/2/APPLAB-69-18-2770-1.pd

Is there a Role for Preoperative Infusion or Intraoperative Cholangiography?

Background: There has been a resurgence of interest in recent years in preoperative infusion cholangiography (PIC). The role of routine PIC compared to routine intraoperative cholangiography (IOC) has not been clearly defined

Gamification for Teamwork Skills: Can a Challenge-based Online Tournament Help Students Learn New Knowledge Collaboratively in Teams?

The interest in deploying innovative technologies with gamification to engage student learning in enjoyable style has been growing. This study aimed to investigate whether a purposely designed eTournament with the integration of concepts of gamification and team development could help the participating tertiary education students (N=416) from a variety of backgrounds in terms of culture and discipline to learn to work in teams collaboratively in a challenge-based online game. The qualitative data collected from the top 10 teams’ online discussions supported that the thoughtful design of the eTournament did facilitate their development of teamwork skills. In addition, quantitative data collected from two of the Post-game Questionnaire questions indicated that over 79% of the respondents strongly agree or agree that they enjoyed the eTournamentin general, and over 84% of respondents strongly agree or agree that they become more aware of the seventeen United Nations Sustainable Development Goals because of the eTournament. Notwithstanding, findings in this study show little evidence in supporting team-playing in PaGamO due to the design of the game regardless of the teamwork skills developed in the early stage of the eTournament. Suggestions to address the limitations of this study are also presented for future improvement

Limiting current in a relativistic diode under the condition of magnetic insulation

The maximum emission current density is calculated for a time-independent, relativistic, cycloidal electron flow in a diode that is under the condition of magnetic insulation. Contrary to conventional thinking, this maximum current is not determined by the space charge limited condition on the cathode, even when the emission velocity of the electrons is assumed to be zero. The self electric and magnetic fields associated with the cycloidal flow are completely accounted for. This maximum current density is confirmed by a two-dimensional, fully electromagnetic and fully relativistic particle-in-cell code. © 2003 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71144/2/PHPAEN-10-11-4489-1.pd