2,887 research outputs found

    Thermal Expansion and Magnetostriction Studies of a Kondo Lattice Compound: Ceagsb2

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    We have investigated a single crystal of CeAgSb2 using low field ac-susceptibility, thermal expansion and magnetostriction measurements in the temperature range 1.5K to 90K. The ac-susceptibility exhibits a sharp peak at 9.7K for both B//c and B perp c due to the magnetic ordering of the Ce moment. The thermal expansion coefficient alpha, exhibits highly anisotropic behaviour between 3K and 80K : alpha is positive for dL/L perp c, but negative for dL/L // c. Furthermore, alpha (for dL/L) perp c (i.e. in ab-plane) exhibits a sharp peak at TN followed by a broad maximum at 20K, while a sharp negative peak at TN followed by a minimum at 20K has been observed for (dL/L //) the c direction. The observed maximum and minimum in alpha(T) at 20K have been attributed to the crystalline field effect on the J=5/2 state of the Ce3+ ion. The magnetostriction also exhibits anisotropic behaviour with a large magnetostriction along the c-axis. The ab-plane magnetostriction exhibits a peak at B=3.3T at 3K, which is consistent with the observed peak in the magnetoresistance measurements.Comment: 4 Pages (B5), 3 figures, submitted to SCES200

    Test of Information Theory on the Boltzmann Equation

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    We examine information theory using the steady-state Boltzmann equation. In a nonequilibrium steady-state system under steady heat conduction, the thermodynamic quantities from information theory are calculated and compared with those from the steady-state Boltzmann equation. We have found that information theory is inconsistent with the steady-state Boltzmann equation.Comment: 12 page

    Multi-band spectroscopy of inhomogeneous Mott-insulator states of ultracold bosons

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    In this work, we use inelastic scattering of light to study the response of inhomogeneous Mott-insulator gases to external excitations. The experimental setup and procedure to probe the atomic Mott states are presented in detail. We discuss the link between the energy absorbed by the gases and accessible experimental parameters as well as the linearity of the response to the scattering of light. We investigate the excitations of the system in multiple energy bands and a band-mapping technique allows us to identify band and momentum of the excited atoms. In addition the momentum distribution in the Mott states which is spread over the entire first Brillouin zone enables us to reconstruct the dispersion relation in the high energy bands using a single Bragg excitation with a fixed momentum transfer.Comment: 19 pages, 7 figure

    The goldstone real-time connected element interferometer

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    Connected element interferometry (CEI) is a technique of observing a celestial radio source at two spatially separated antennas and then interfering the received signals to extract the relative phase of the signal at the two antennas. The high precision of the resulting phase delay data type can provide an accurate determination of the angular position of the radio source relative to the baseline vector between the two stations. This article describes a recently developed connected element interferometer on a 21-km baseline between two antennas at the Deep Space Network's Goldstone, California, tracking complex. Fiber-optic links are used to transmit the data to a common site for processing. The system incorporates a real-time correlator to process these data in real time. The architecture of the system is described, and observational data are presented to characterize the potential performance of such a system. The real-time processing capability offers potential advantages in terms of increased reliability and improved delivery of navigational data for time-critical operations. Angular accuracies of 50-100 nrad are achievable on this baseline

    Preprototype nitrogen supply subsystem development

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    The design and development of a test stand for the Nitrogen Generation Module (NGM) and a series of tests which verified its operation and performance capability are described. Over 900 hours of parametric testing were achieved. The results from this testing were then used to design an advanced NGM and a self contained, preprototype Nitrogen Supply Subsystem. The NGM consists of three major components: nitrogen generation module, pressure controller and hydrazine storage tank and ancillary components. The most important improvement is the elimination of all sealing surfaces, achieved with a total welded or brazed construction. Additionally, performance was improved by increasing hydrogen separating capability by 20% with no increase in overall packaging size

    Keep Your Money: Let the West Pay for Its Own Water Projects

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    Protecting New Mexico’s Waters: A Blueprint for the Future

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    Aquatic species are imperiled by water diversions, introduced species, pollution and now climate change. In the western U.S., water law rewards the withdrawal and use of water, rather than leaving water instream for ecological, recreational and other purposes. New Mexico has no statutory protections for environmental flows and is increasing its diversions of water from rivers. This paper discusses the status of instream flows in the state and proposes policies to better protect the state’s waters

    Antenuptial Agreements and California Law: Building Confidence

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    This Comment examines the legal issues surrounding the increased popularity of antenuptial agreements. The author argues that California law has failed to recognize the close and trusting nature of the parties\u27 relationship and has treated prospective spouses as arm\u27s-length adversaries. The author examines the validity of California\u27s arm\u27s-length analysis of antenuptial agreements and contrasts this approach with that of the majority of jurisdictions, which impose a fiduciary relationship on parties entering into antenuptial agreements. The author concludes that the California legislature should adopt the majority view, in accordance with public policy and the intimations of the California Supreme Court

    Keep Your Money: Let the West Pay for its Own Water Projects

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    The question posed here is what role the federal government should play in responding to the western water crisis, in light of the changes in the social and political landscape that have occurred in the last decade. My thesis is that solutions to water needs that are funded locally are more likely to be sustainable than those produced through national appropriations. My thinking is affected by the work I did on a Presidential commission that recommended sustainability be the cornerstone of western water policy
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