CHIRAL DYNAMICS AND THE SPIN STRUCTURE OF THE NUCLEON AT LOW ENERGIES

Experimental point-projection shadow microscope (PPM) images of uncoated, unstained purple membrane (PM, bacteriorhodopsin, a membrane protein from Halobacterium holobium) were obtained recently using 100 volt electrons. The membrane thickness is about 5 nm and the hexagonal unit cell dimension 6 nm. The images show contrast around the edges of small holes, as shown in figure 1. The interior of the film is opaque. Since the inelastic mean free path for 100V electrons in carbon (about 6 Å) is much less than the sample thickness, the question arises that how much, if any, transmission of elastically scattered electrons occurs. A large inelastic contribution is also expected, attenuated by the reduced detection efficiency of the channel plate at low energies. Quantitative experiments using an energy-loss spectrometer are planned. Recently Shedd has shown that at about 100V contrast in PPM images of thin gold films can be explained as Fresnel interference effects between different pinholes in the film, separated by less than the coherence width.

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Electrical Damage Due to Low Energy Plasma Processing of GaAs Structures

MRS Proceedings ◽

10.1557/proc-223-209 ◽

1991 ◽

Vol 223 ◽

Author(s):

Hans P. Zappe ◽

Gudrun Kaufel

Keyword(s):

Chemical Processes ◽

Low Energy ◽

Electrical Behavior ◽

Rapid Thermal Anneal ◽

High Temperature Anneal ◽

Significant Damage ◽

Low Energies ◽

Long Time ◽

Physical Plasma

ABSTRACTThe effect of numerous plasma reative ion etch and physical milling processes on the electrical behavior of GaAs bulk substrates has been investigated by means of electric microwave absorption. It was seen that plasma treatments at quite low energies may significantly affect the electrical quality of the etched semiconductor. Predominantly physical plasma etchants (Ar) were seen to create significant damage at very low energies. Chemical processes (involving Cl or F), while somewhat less pernicious, also gave rise to electrical substrate damage, the effect greater for hydrogenic ambients. Whereas rapid thermal anneal treatments tend to worsen the electrical integrity, some substrates respond positively to long-time high temperature anneal steps.

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Response of $D^0$ U-LAr Calorimeters at Low-Energies and the Effect of Oxygen Contamination on Observed Signals

10.2172/1424424 ◽

1994 ◽

Author(s):

Robert James Hirosky

Keyword(s):

Oxygen Contamination ◽

Low Energies ◽

Effect Of Oxygen

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Interaction of ditertiary phosphines with phenyl- and 1-naphthyldithiocarbamatonickel(II)

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19851383 ◽

1985 ◽

Vol 50 (6) ◽

pp. 1383-1390

Author(s):

Aref A. M. Aly ◽

Ahmed A. Mohamed ◽

Mahmoud A. Mousa ◽

Mohamed El-Shabasy

Keyword(s):

Thermal Analysis ◽

Powder Diffraction ◽

Spin Structure ◽

Magnetic Measurements ◽

Mixed Ligand ◽

Mixed Ligand Complexes ◽

X Ray ◽

Square Planar

The synthesis of the following mixed ligand complexes is reported: [Ni(phdtc)2(dpm)2], [Ni(phdtc)2(dpe)2], [Ni(phdtc)2(dpp)3], [Ni(1-naphdtc)2(dpm)2], [Ni(1-naphdtc)2], and [Ni(1-naphdtc)2(dpp)2], where phdtc = PhNHCSS-, 1-naphdtc = 1-NaPhNHCSS-, dpm = Ph2PCH2PPh2, dpe = Ph2P(CH2)2PPh2, and dpp = Ph2P(CH2)3PPh2. The complexes are characterised by microanalysis, IR and UV-Vis spectra, magnetic measurements, conductivity, X-ray powder diffraction, and thermal analysis. All the mixed ligand complexes are diamagnetic, and thus a square-planar or square-pyramidal (low-spin) structure was proposed for the present complexes.

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Effects of the solar wind termination shock and heliosheath on theheliospheric modulation of galactic and anomalous Helium

Annales Geophysicae ◽

10.5194/angeo-22-3063-2004 ◽

2004 ◽

Vol 22 (8) ◽

pp. 3063-3072 ◽

Cited By ~ 15

Author(s):

U. W. Langner ◽

M. S. Potgieter

Keyword(s):

Solar Wind ◽

Cosmic Ray ◽

Magnetic Polarity ◽

Termination Shock ◽

Shock Acceleration ◽

Diffusive Shock Acceleration ◽

Cosmic Ray Modulation ◽

Low Energies ◽

Solar Wind Termination Shock ◽

Charge Sign

Abstract. The interest in the role of the solar wind termination shock and heliosheath in cosmic ray modulation studies has increased significantly as the Voyager 1 and 2 spacecraft approach the estimated position of the solar wind termination shock. The effect of the solar wind termination shock on charge-sign dependent modulation, as is experienced by galactic cosmic ray Helium (He++) and anomalous Helium (He+), is the main topic of this work, and is complementary to the previous work on protons, anti-protons, electrons, and positrons. The modulation of galactic and anomalous Helium is studied with a numerical model including a more fundamental and comprehensive set of diffusion coefficients, a solar wind termination shock with diffusive shock acceleration, a heliosheath and particle drifts. The model allows a comparison of modulation with and without a solar wind termination shock and is applicable to a number of cosmic ray species during both magnetic polarity cycles of the Sun. The modulation of Helium, including an anomalous component, is also done to establish charge-sign dependence at low energies. We found that the heliosheath is important for cosmic ray modulation and that its effect on modulation is very similar for protons and Helium. The local Helium interstellar spectrum may not be known at energies

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