196,701 research outputs found
Mary and Sandra Giles with Nancy, circa 1860-1885
No full textCarte-de-visite of Mary and Sandra Giles with Nancy, circa 1860-1885. Photograph taken by E. M. Recher, Hagerstown, Maryland. From the Humrichouse Family photograph album. To view the entire album, please visit http://hdl.handle.net/1903.1/11824
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
Effects of spin symmetry breaking in topological insulators
No full textTopological insulators are one of the most thoroughly investigated systems in condensed matter physics over the last years. In these systems, a prominent role is inevitably taken by time-reversal symmetry, which leads to Kramers theorem and symmetry protected edge states. However, Kramers theorem does not imply that the spin-z component is a good quantum number. This thesis sheds light on several phenomena that appear in topological insulators without this spin conservation, for example in the context of generic helical liquids. A topological insulator strip is examined which allows for forward- and backscattering between the edge states. This results in a measurable effect on the conductance. Furthermore, interfaces between edge-state regions with induced superconductivity, strong interactions and broken spin conservation are analyzed. Calculations using Luttinger liquid theory reveal parafermions at these interfaces. Finally, disorder in the Kane-Mele model in combination with Rashba spin-orbit coupling is studied. It is found that disorder can lead to a topological phase, the topological Anderson insulator, even though the clean system is a trivial insulator
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
Correlated spin transport in nanostructures: entanglement creation and spin filtering
No full textThe electron spin for electronics has only recently attracted much interest.
The idea to use spin|as opposed to charge|as the fundamental data carrier
was motivated by recent experiments that showed unusually long spindephasing
times up to microseconds for electrons in semiconductors as well
as phase coherent transport over distances exceeding one hundred micrometers.
In addition, experiments demonstrated the injection of spin-polarized
carriers|electrons and holes|from a magnetic into a non-magnetic semiconductor
which opens the door for various applications in spin electronics
(spintronics). Besides the broad use of the electron spin in conventional devices,
like in giant magnetoresistance (GMR) based magnetic read-out heads
for computer hard drives or for non-volatile memories, the spin of the electron
con�ned in nanostructures such as semiconductor quantum dots serves
as a natural realization of a quantum bit (qubit). A quantum computer
uses explicitly the quantum nature of systems where phase coherence and
entanglement play a crucial role which requires a radically new design of
the underlying computer hardware. In particular, entangled spin qubits,
combined with the ability to control them via their charges, can serve as
electronic EPR (Einstein-Podolsky-Rosen)-pairs in wires, i.e. pairs of electrons
which are spatially separated (and uncorrelated) but still correlated
with respect to their spins. Such entangled particles are the resource for
secure quantum communication protocols which have been experimentally
implemented using photons|the quantized units of light. The equivalent
experiments for massive particles like electrons in a solid-state environment
have not yet been performed, although their need cannot be overestimated,
both from a practical point of view and also from a more fundamental one.
In this Thesis, we address the question of creating such nonlocal spinentangled
electron pairs in a way that is suitable to detect the produced entanglement
in transport experiments via their current-noise properties. We discuss various setups|entanglers| where Cooper pairs in a superconductor
with spin singlet wave functions act as the source of spin-entanglement. In
the presence of a voltage bias between the superconductor and two spatially
separated normal conducting leads which are weakly tunnel-coupled to the
superconductor, the electrons of a Cooper pair can tunnel coherently|in an
Andreev (pair-)tunneling process|from the superconductor to the normal
leads thereby remaining in the spin singlet state. This produces a current
carried by pairs of spin-entangled electrons in the leads. In these setups,
superconducting pair-correlations and Coulomb interaction between the two
electrons are competing features. On the one hand, the orbital wave function
of a Cooper pair is symmetric which favors the tunneling of both electrons
into the same outgoing arm of the entangler. Such processes are unwanted
since they do not lead to nonlocality. On the other hand, in small lowdimensional
quantum con�ned nanostructres, electron-electron interaction
becomes sizable and can be used to separate the two electrons of a Cooper
pair. We exploit such strong correlations between the electron charges of
a pair by using either quantum dots in the Coulomb blockade regime, one
dimensional wires with Luttinger liquid properties or resistive outgoing leads
coupled to the superconductor. We calculate the two competing tunneling
currents from the superconductor to di�erent leads (desired pair-split process)
and to the same lead (unwanted local process) in detail. By comparing
their ratio, we can estimate the e�ciency of the entangler and see how it
depends on various system parameters. This then allows us to identify a
regime of experimental accessibility where the pair-split process is dominant.
The ability to have (coherent) control over single electron spins in semiconductor
nanostructures is crucial in view of quantum computing with electron
spins. In particular, spin-�ltering and spin read-out is of great importance.
For this we consider a quantum dot in the Coulomb blockade regime
weakly coupled to current leads and show that in the presence of a magnetic
�eld the dot acts as an e�cient spin �lter (at the single-spin level) which
produces a spin-polarized current. Conversely, if the leads are fully spinpolarized,
the magnitude of the transport current through the dot depends
on the spin state of the dot. Quantum dots permit the control of charge
down to single electrons. It is therefore feasible to consider a single spin 1/2
on the dot|a spin qubit|which can be read out by a current. Combined
with electron spin resonance (ESR) techniques this allows one to operate the
quantum dot as a single spin memory with read-in and read-out capabilities
Simulation of thermal plant optimization and hydraulic aspects of thermal distribution loops for large campuses
No full textFollowing an introduction, the author describes Texas A&M University and its utilities system. After that, the author presents how to construct simulation models for chilled water and heating hot water distribution systems. The simulation model was used in a $2.3 million Ross Street chilled water pipe replacement project at Texas A&M University. A second project conducted at the University of Texas at San Antonio was used as an example to demonstrate how to identify and design an optimal distribution system by using a simulation model. The author found that the minor losses of these closed loop thermal distribution systems are significantly higher than potable water distribution systems. In the second part of the report, the author presents the latest development of software called the Plant Optimization Program, which can simulate cogeneration plant operation, estimate its operation cost and provide optimized operation suggestions. The author also developed detailed simulation models for a gas turbine and heat recovery steam generator and identified significant potential savings. Finally, the author also used a steam turbine as an example to present a multi-regression method on constructing simulation models by using basic statistics and optimization algorithms. This report presents a survey of the author??s working experience at the Energy Systems Laboratory (ESL) at Texas A&M University during the period of January 2002 through March 2004. The purpose of the above work was to allow the author to become familiar with the practice of engineering. The result is that the author knows how to complete a project from start to finish and understands how both technical and nontechnical aspects of a project need to be considered in order to ensure a quality deliverable and bring a project to successful completion. This report concludes that the objectives of the internship were successfully accomplished and that the requirements for the degree of Degree of Engineering have been satisfied
- …
