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Methods of Opacity Calculations

Description: "Methods for calculating the opacity of materials at high temperatures are discussed in this report. Minor improvements are outlined for the treatment of continuous absorption processes, and a small error usually made in treating the scattering process is corrected. In contrast to all previous calculations of opacity, the effect of line absorption is carefully examined, for it may well be the dominant process under certain conditions of temperature and density. Detailed methods for calculating the line absorption contribution are, therefore, developed. To illustrate the principles involved, the opacity of pure iron at a temperature of 1000 volts and normal density is worked out in detail" (p. ii).
Date: 1949
Creator: Mayer, Harris
Partner: UNT Libraries Government Documents Department

Field Errors in Hybrid Insertion Devices

Description: Hybrid magnet theory as applied to the error analyses usedin the design of Advanced Light Source (ALS) insertion devices isreviewed. Sources of field errors in hybrid insertion devices arediscussed.
Date: February 3, 1995
Creator: Schlueter, R.D.
Partner: UNT Libraries Government Documents Department

Resonant soft X-ray emission spectroscopy of liquids

Description: We present now a possible way to carry out soft-x-rayfluorescence spectroscopy of liquids. The liquid cell has a window toattain compatibility with UHV conditions of the spectrometer andbeamline, The synchrotron radiation enters the liquid cell through a 100nm-thick silicon nitride window and the emitted xrays exit through thesame window. This allows in particular liquid solid interfaces to bestudied. Such a liquid cell has been used to study the electronicstructure of a variety of systems ranging from water solutions ofinorganic salts and inertial drugs to nano materials and actinidecompounds in their wet conditions.
Date: October 27, 2004
Creator: Guo, J.-H.; Augustsson, A.; Englund, C.-J. & Nordgren, J.
Partner: UNT Libraries Government Documents Department

RECENT BEAM MEASUREMENTS AND NEW INSTRUMENTATION AT THE ADVANCED LIGHT SOURCE

Description: The Advanced Light Source (ALS) in Berkeley was the first of the soft x-ray third generation light source ever built, and since 1993 has been in continuous and successful operation serving a large community of users in the VUV and soft x-ray community. During these years the storage ring underwent through several important upgrades that allowed maintaining the performance of this veteran facility at the forefront. The ALS beam diagnostics and instrumentation have followed a similar path of innovation and upgrade and nowadays include most of the modem and last generation devices and technologies that are commercially available and used in the recently constructed third generation light sources. In this paper we will not focus on such already widely known systems, but we will concentrate our effort in the description of some measurements techniques, instrumentation and diagnostic systems specifically developed at the ALS and used during the last few years.
Date: May 5, 2008
Creator: Sannibale, Fernando; Baptiste, Kenneth; Barry, Walter; Chin, Michael; Filippetto, Daniele; Jaegerhofer, Lukas et al.
Partner: UNT Libraries Government Documents Department

Enabling instrumentation and technology for 21st century light sources

Description: We present the summary from the Accelerator Instrumentation and Technology working group, one of the five working groups that participated in the BES-sponsored Workshop on Accelerator Physics of Future Light Sources held in Gaithersburg, MD September 15-17, 2009. We describe progress and potential in three areas: attosecond instrumentation, photon detectors for user experiments, and insertion devices.
Date: June 1, 2010
Creator: Byrd, J.M.; Shea, T.J.; Denes, P.; Siddons, P.; Attwood, D.; Kaertner, F. et al.
Partner: UNT Libraries Government Documents Department

Microstructure evolution of tin under electromigration studied bysynchrotron X-Ray micro-diffraction

Description: Under constant current electromigration, white tin(?-Sn)exhibited a resistance drop of up to 10 percent. It has a body centertetragonal (BCT) structure, and the resistivity along the aand b axes is35 percent smaller than that along the c axis.Microstructure evolutionunder electromigration could be responsible for the resistance drop.Synchrotron radiation white beam x-ray microdiffraction was used to studythis evolution. Both stress and grain orientation was studied.Grain-by-grain analysis was obtained from the diffracted Laue patternsabout the changes of grain orientation during electromigration testing inex-situ and in-situ samples. We observed that high resistance grainsreorient with respect to the neighboring low resistance grains, mostlikely by grain rotation of the latter. A different mechanism ofmicrostructure evolution under electromigration from the normal graingrowth is proposed and discussed.
Date: May 5, 2005
Creator: Wu, Albert T.; Lloyd, J.R.; Tamura, N. & Tu, K.-N.
Partner: UNT Libraries Government Documents Department

Correlation between exchange bias and pinned interfacialspins

Description: Using x-ray magnetic circular dichroism, we have detectedthe very interfacial spins that are responsible for the horizontal loopshift in three different exchange bias sandwiches, chosen because oftheir potential for device applications. The "pinned" uncompensatedinterfacial spins constitute only a fraction of a monolayer and do notrotate in an external magnetic field since they are tightly locked to theantiferromagnetic lattice. A simple extension of the Meiklejohn and Beanmodel is proposed to account quantitatively for the exchange bias fieldsin the three studied systems from the experimentally determined number ofpinned moments and their sizes.
Date: July 1, 2003
Creator: Ohldag, H.; Scholl, A.; Nolting, F.; Arenholz, E.; Maat, S.; Young, A.T. et al.
Partner: UNT Libraries Government Documents Department

Effects of light on the resistivity of chemical vapor deposited graphene films

Description: This article reports that the resistance of a chemical vapor deposition (CVD) grown graphene film transferred onto an SiO₂ substrate increases to higher saturation values upon exposure to light of decreasing wavelength from the visible to ultraviolet.
Date: October 24, 2016
Creator: Mo, Yudong; Pérez, José M.; Ye, Zhou; Zhao, Lei; Yang, Shizhong; Tan, Liuxi et al.
Partner: UNT College of Arts and Sciences

The Use of Light Imagery in the Fiction of Ernest Hemingway

Description: The purpose of this study is to identify and examine the light imagery in Ernest Hemingway's major fiction and to evaluate its importance. In this study, imagery is defined as descriptive words or figures of speech that create pictures in the mind. In general, this definition will be applied to Hemingway's use of light and dark.
Date: August 1967
Creator: DePasqual, Joseph Albert
Partner: UNT Libraries

Monte Carlo Calculations of Reflected Intensities for Real Spherical Atmospheres

Description: To calculate the emergent radiation field, a realistic atmospheric model and algorithm must be developed. The radiation field may be characterized by the emergent intensities of scattered light. This is possible only if the algorithm determines these intensities as dependent upon atmospheric and angular parameters.
Date: January 1969
Creator: Montgomery, John A.
Partner: UNT Libraries