41,253 research outputs found
Investigation on the Tachyonic Neutrino
According to the experimental data, it is still controversial whether the
neutrinos, especially the electron-neutrino and muon-neutrino, can be
considered as the fermionic spinorial tachyons, and there is still no reliable
report on the existence of the right-handed neutrinos. In this letter, we show
that the neutrinos with the single handedness can not be the tachyons, but only
those of the both handedness can be. Several implications of this result are
discussed.Comment: 13 pages, latex, no figure
The design of caring environments and the quality of life of older people
There has been little systematic research into the design of care environments for older people. This article reviews empirical studies from both the architectural and the psychological literature. It outlines the instruments that are currently available for measuring both the environment and the quality of life of older people, and it summarises the evidence on the layout of buildings, the sensory environment and the privacy of residents. The conclusion is drawn that all evidence-based design must be a compromise or dynamic and, as demands on the caring environment change over time, this compromise must be re-visited in the form of post-occupancy evaluation
XeCl laser pumped iodine laser using t-C4F9I
An iodine photodissociation laser using t-C4F9I as the active material was pumped by an XeCl laser. An iodine laser output energy of 3 mJ with pulse duration of 25 ns was obtained when the pumping pulse energy was 80 mJ, the iodide pressure was 70 torr, and the reflectance of the output mirror was 85 percent. The high pumping efficiency and low threshold pump power achieved in this experiment are attributable to the high absorption cross section at the pump laser wavelength (308 nm) of the iodide used
Direct solar-pumped iodine laser amplifier
The optimum conditions of a solar pumped iodine laser are found in this research for the case of a continuous wave operation and a pulsed operation. The optimum product of the pressure(p) inside the laser tube and the tube diameter(d) was pd=40 approx. 50 torr-cm on the contrary to the case of a high intensity flashlamp pumped iodine laser where the optimum value of the product is known to be pd=150 torr-cm. The pressure-diameter product is less than 1/3 of that of the high power iodine laser. During the research period, various laser materials were also studied for solar pumping. Among the laser materials, Nd:YAG is found to have the lowest laser threshold pumping intensity of about 200 solar constant. The Rhodamine 6G was also tested as the solar pumped laser material. The threshold pumping power was measured to be about 20,000 solar constant. The amplification experiment for a continuously pumped iodine laser amplifier was performed using Vortek solar simulator and the amplification factors were measured for single pass amplification and triple pass amplification of the 15 cm long amplifier tube. The amplification of 5 was obtained for the triple pass amplification
Comments on `` Black Hole Entropy from Conformal Field Theory in Any Dimension ''
In a recent letter, Carlip proposed a generalization of the
Brown-Henneaux-Strominger construction to any dimension. We present two
criticisms about his formulation.Comment: 4 pages, Enriched version for the accepted one (Phys. Rev. Lett.
The Corrected Log N-Log Fluence Distribution of Cosmological Gamma-Ray Bursts
Recent analysis of relativistically expanding shells of cosmological
gamma-ray bursts has shown that if the bursts are cosmological, then most
likely total energy (E_0) is standard and not peak luminosity (L_0). Assuming a
flat Friedmann cosmology (q_o = 1/2, Lambda = 0) and constant rate density
(rho_0) of bursting sources, we fit a standard candle energy to a uniformly
selected log N-log S in the BATSE 3B catalog correcting for fluence efficiency
and averaging over 48 observed spectral shapes. We find the data consistent
with E_0 = 7.3^{+0.7}_{-1.0} X 10^{51} ergs and discuss implications of this
energy for cosmological models of gamma-ray bursts.Comment: A five page LateX file that uses the Revtex conference proceedings
macro aipbook.sty, and includes three postscript figures using psfig. To Be
published in the Proceedings of the Third Hunstville Symposium on Gamma-Ray
Bursts, eds. C. Kouveliotou, M.S. Briggs and G.J. Fishman (New York:AIP).
Postscript version availible at http://nis-www.lanl.gov/~jsbloom/LOG_S.p
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