Consequences of negative differential electron mobility in insulated gate field effect transistors

We study the consequences of negative differential electron mobility in insulated gate field effect transistors (FETS) using the field model. We show that, in contrast to the case of the monotonic velocity saturation model, the field distributions in a short-channel FET may be described by the gradual channel approximation even for high drain-to-source voltages. The current-voltage dependence of the short-channel FET should have a branch with a negative slope. The FET exhibits a negative differential resistance and may show convective or absolute instability, depending on the applied voltages. The fluctuation growth is governed by the diffusion law with a negative effective diffusion coefficient.Comment: 4 pages, 2 figure

The telephone in family practice

In a time-and-motion study in family practice it was found that 35,8% of all patient contact was per telephone. The study further revealed that 12,3% of total practice time was spent on the telephone, stressing its importance as a useful tool. in family practice. The study supports others which suggest that 'telephone medicine' is worthy of careful examination in terms of cost-effectiveness. The implications for the doctor-patient relationship are also considered

An Application of Social Network Analysis on Military Strategy, System Networks and the Phases of War

The research developed in this study will utilize Social Network and Graph Theory terminology and methodology applied to groups of systems, rather than individuals within a given system, in order to shape strategic level goals. With regard to military operations, Social Network Analysis has been used to show that enemy networks and relationships can be accurately represented using weighted layers with weighted relationships in order to identify the key player(s) that must be influenced and/or removed so that a particular effect on the enemy might be realized. Social Network Analysis is therefore a significant tool concerning tactical level of operations that aids in developing a targeting methodology which aids tactical commanders in mission planning, however has never been applied to strategic levels of Command. Like previous key player problems, this research will utilize system attributes and global relational strengths as inputs. The output results will rank order representative systems of interest that satisfy the constraints and desired objectives within a particular Phase of War. This work will apply and extend the tools of Social Network Analysis structure and techniques to a theater level mission

Steering effects on growth instability during step-flow growth of Cu on Cu(1,1,17)

Kinetic Monte Carlo simulation in conjunction with molecular dynamics simulation is utilized to study the effect of the steered deposition on the growth of Cu on Cu(1,1,17). It is found that the deposition flux becomes inhomogeneous in step train direction and the inhomogeneity depends on the deposition angle, when the deposition is made along that direction. Steering effect is found to always increase the growth instability, with respect to the case of homogeneous deposition. Further, the growth instability depends on the deposition angle and direction, showing minimum at a certain deposition angle off-normal to (001) terrace, and shows a strong correlation with the inhomogeneous deposition flux. The increase of the growth instability is ascribed to the strengthened step Erlich Schwoebel barrier effects that is caused by the enhanced deposition flux near descending step edge due to the steering effect.Comment: 5 page

Book Reviews : Boekbesprekings

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Formation of plasma around a small meteoroid: 1. Kinetic theory

This article is a companion to Dimant and Oppenheim [2017] https://doi.org/10.1002/2017JA023963.This paper calculates the spatial distribution of the plasma responsible for radar head echoes by applying the kinetic theory developed in the companion paper. This results in a set of analytic expressions for the plasma density as a function of distance from the meteoroid. It shows that at distances less than a collisional mean free path from the meteoroid surface, the plasma density drops in proportion to 1/R where R is the distance from the meteoroid center; and, at distances much longer than the mean‐free‐path behind the meteoroid, the density diminishes at a rate proportional to 1/R2. The results of this paper should be used for modeling and analysis of radar head echoes.This work was supported by NSF grant AGS-1244842. (AGS-1244842 - NSF

Multiple Quantum NMR Dynamics in Dipolar Ordered Spin Systems

We investigate analytically and numerically the Multiple Quantum (MQ) NMR dynamics in systems of nuclear spins 1/2 coupled by the dipole-dipole interactions in the case of the dipolar ordered initial state. We suggest two different methods of MQ NMR. One of them is based on the measurement of the dipolar temperature in the quasi-equilibrium state which establishes after the time of order T2 after the MQ NMR experiment. The other method uses an additional resonance 45^0 -pulse after the preparation period of the standard MQ NMR experiment in solids. Many-spin clusters and correlations are created faster in such experiments than in the usual MQ NMR experiments and can be used for the investigation of many-spin dynamics of nuclear spins in solids.Comment: 11 pages, 3 figures. accepted for publication in Physical Review

One loop renormalization for the axial Ward-Takahashi identity in Domain-wall QCD

We calculate one-loop correction to the axial Ward-Takahashi identity given by Furman and Shamir in domain-wall QCD. It is shown perturbatively that the renormalized axial Ward-Takahashi identity is satisfied without fine tuning and the ``conserved'' axial current receives no renormalization, giving $Z_A=1$. This fact will simplify the calculation of the pion decay constant in numerical simulations since the decay constant defined by this current needs no lattice renormalization factor.Comment: 16 pages, 3 axodraw.sty figure

Orbit equivalence rigidity for ergodic actions of the mapping class group

We establish orbit equivalence rigidity for any ergodic, essentially free and measure-preserving action on a standard Borel space with a finite positive measure of the mapping class group for a compact orientable surface with higher complexity. We prove similar rigidity results for a finite direct product of mapping class groups as well.Comment: 11 pages, title changed, a part of contents remove