Measurement of the D-D fusion neutron energy spectrum and variation of the peak width with plasma ion temperature

and disposal, in whole or in part by or for the United States govern-ment is permitted. By acceptance of this article, the publisher and/or recipient ac-knowledges the U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright covering this paper. 1 Measurement of the d-d fusion neutron energy spectrum and variation of the peak width with plasma ion temperature W. A. Fisher*, S. H. Chen*, D. Gwinnt, R. R. Parkert We report a set of neutron spectrum measurements made at the Alcator C tokamak under ohmic heating conditions. It has been found that the width of the D-D fusion neutron peak increases with the plasma ion temperature consistent with the theoretical prediction. In particular the neutron spectra resulting from the sum of many plasma discharges with ion temperatures of 780 eV and 1050 eV have been ob-tained. The width for the 780 eV case is 64 +9,-11 keV and that of the 1050 eV case, 81 +10,-14 keV FWHM, corresponding to ion tempera-tures of 740 eV and 1190 eV respectively

Determining surface magnetization and local magnetic moments with atomic scale resolution

We propose a method to determine the direction of surface magnetization and local magnetic moments on the atomic scale. The method comprises high resolution scanning tunneling microscope experiments in conjunction with first principles simulations of the tunneling current. The potential of the method is demonstrated on a model system, antiferromagnetic Mn overlayers on W(110). We expect that it will ultimately allow to study the detailed changes of magnetic surface structures in the vicinity of dopants or impurities.Comment: Four pages (RevTeX) and five figures (EPS). For related papers see http://cmmp.phys.ucl.ac.uk/~wah

Tip effects in scanning tunnelling microscopy of atomic-scale magnetic structures

The spin-polarized scanning tunnelling microscope (STM) can in principle resolve not only the electronic, but also the magnetic surface structure. We model recent STM measurements achieving magnetic resolution on the atomic scale by a first-principles method. It is shown that the signature of a specific magnetic or non-magnetic STM tip can unambiguously be identified. It is also established that the model of Tersoff and Hamann would yield an electronic as well as magnetic contrast of the surface which is well below STM resolution.Comment: Four pages (RevTeX) and three figures (EPS). For related papers see http://cmmp.phys.ucl.ac.uk/~wah/index.htm

Effects of Simple Carbohydrate vs. Carbohydrate-Protein Intake on Glucose Homeostasis Following Intense Exercise

Kluka, J., Baskerville, J., Clifton, K., Fisher, K., Marks, D., Weidner, C., Veerabhadrappa, P. and Braun, W.A. (FACSM), Shippensburg University, Shippensburg, PA. Purpose: To test the effects of simple carbohydrate (CHO) and the combination of CHO and protein on blood glucose (BG) clearance following intense anaerobic exercise. Methods: Eight members (age = 18.8 ± 1.4 years) of the Shippensburg University Football team participated in the study. On separate test days, subjects were given either a placebo (PL) drink, a CHO drink (74 g CHO in 473 ml), or a carbohydrate-protein (C-PRO) drink (58 g CHO and 16 g PRO in 473 ml), upon completing the exercise bout. Before exercise, baseline measurements were taken for BG and heart rate. The subject then completed a 90-sec modified Wingate protocol (resistance set at 70% of the individual’s Wingate protocol resistance). BG was tested post-exercise, and every ten minutes after ingestion of the solution for 60 min. Results: Neither total revolutions completed (PL = 123.0±5.0; CHO = 126.9±3.9; C-PRO = 125.4±2.8) nor post-exercise BG (mg.dl-1) differed across treatments (PL = 88.6±6.5; CHO = 93.1±4.0; C-PRO = 101.1±4.7). However, CHO elicited the highest (p\u3c0.05) mean BG during recovery and the lowest BG was found in the PL. Conclusion: While matching post-exercise energy intake, C-PRO elicited a smaller BG area than CHO but tended to be larger than that of PL (p=0.052). C-PRO may be a better choice for post-exercise intake if aiming to maintain glucose homeostasis during recovery

Measurement of Fluorescence Phenomena from Yttrium and Gadolinium Oxysulfide Phosphors using a 45-MeV Proton Beam

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

The Role of Surface Entropy in Statistical Emission of Massive Fragments from Equilibrated Nuclear Systems

Statistical fragment emission from excited nuclear systems is studied within the framework of a schematic Fermi-gas model combined with Weisskopf's detailed balance approach. The formalism considers thermal expansion of finite nuclear systems and pays special attention to the role of the diffuse surface region in the decay of hot equilibrated systems. It is found that with increasing excitation energy, effects of surface entropy lead to a systematic and significant reduction of effective emission barriers for fragments and, eventually, to the vanishing of these barriers. The formalism provides a natural explanation for the occurrence of negative nuclear heat capacities reported in the literature. It also accounts for the observed linearity of pseudo-Arrhenius plots of the logarithm of the fragment emission probability {\it versus} the inverse square-root of the excitation energy, but does not predict true Arrhenius behavior of these emission probabilities

On the relation of Thomas rotation and angular velocity of reference frames

In the extensive literature dealing with the relativistic phenomenon of Thomas rotation several methods have been developed for calculating the Thomas rotation angle of a gyroscope along a circular world line. One of the most appealing concepts, introduced in \cite{rindler}, is to consider a rotating reference frame co-moving with the gyroscope, and relate the precession of the gyroscope to the angular velocity of the reference frame. A recent paper \cite{herrera}, however, applies this principle to three different co-moving rotating reference frames and arrives at three different Thomas rotation angles. The reason for this apparent paradox is that the principle of \cite{rindler} is used for a situation to which it does not apply. In this paper we rigorously examine the theoretical background and limitations of applicability of the principle of \cite{rindler}. Along the way we also establish some general properties of {\it rotating reference frames}, which may be of independent interest.Comment: 14 pages, 2 figure

Fokker-Planck equations and density of states in disordered quantum wires

We propose a general scheme to construct scaling equations for the density of states in disordered quantum wires for all ten pure Cartan symmetry classes. The anomalous behavior of the density of states near the Fermi level for the three chiral and four Bogoliubov-de Gennes universality classes is analysed in detail by means of a mapping to a scaling equation for the reflection from a quantum wire in the presence of an imaginary potential.Comment: 10 pages, 5 figures, revised versio