Interaction of plasmas with intense lasers (open access)

Interaction of plasmas with intense lasers

The interaction of plasmas with intense lasers is an excellent example of how different fields of physics are inter-connected. Invention of the laser and its ongoing development has allowed the creation and study of high temperature, dense matter in the laboratory. The results both advance the underlying plasma science and are relevant to many fields ranging from astrophysics to fusion and nonlinear physics. A brief overview of the interaction physics is given. Selected topics are discussed to illustrate the exciting progress in experimental, theoretical and computational investigations with focused laser intensities up to 10{sup 21} W/cm{sup 2}.
Date: April 30, 1999
Creator: Kruer, W.
System: The UNT Digital Library
Cooperative learning of neutron diffusion and transport theories (open access)

Cooperative learning of neutron diffusion and transport theories

A cooperative group instructional strategy is being used to teach a unit on neutron transport and diffusion theory in a first-year-graduate level, Reactor Theory course that was formerly presented in the traditional lecture/discussion style. Students are divided into groups of two or three for the duration of the unit. Class meetings are divided into traditional lecture/discussion segments punctuated by cooperative group exercises. The group exercises were designed to require the students to elaborate, summarize, or practice the material presented in the lecture/discussion segments. Both positive interdependence and individual accountability are fostered by adjusting individual grades on the unit exam by a factor dependent upon group achievement. Group collaboration was also encouraged on homework assignments by assigning each group a single grade on each assignment. The results of the unit exam have been above average in the two classes in which the cooperative group method was employed. In particular, the problem solving ability of the students has shown particular improvement. Further,the students felt that the cooperative group format was both more educationally effective and more enjoyable than the lecture/discussion format.
Date: April 30, 1999
Creator: Robinson, Michael A.
System: The UNT Digital Library
A DES ASIC Suitable for Network Encryption at 10 Gbps and Beyond (open access)

A DES ASIC Suitable for Network Encryption at 10 Gbps and Beyond

The Sandia National Laboratories (SNL) Data Encryption Standard (DES) Application Specific Integrated Circuit (ASIC) is the fastest known implementation of the DES algorithm as defined in the Federal Information Processing Standards (FIPS) Publication 46-2. DES is used for protecting data by cryptographic means. The SNL DES ASIC, over 10 times faster than other currently available DES chips, is a high-speed, filly pipelined implementation offering encryption, decryption, unique key input, or algorithm bypassing on each clock cycle. Operating beyond 105 MHz on 64 bit words, this device is capable of data throughputs greater than 6.7 Billion bits per second (tester limited). Simulations predict proper operation up to 9.28 Billion bits per second. In low frequency, low data rate applications, the ASIC consumes less that one milliwatt of power. The device has features for passing control signals synchronized to throughput data. Three SNL DES ASICS may be easily cascaded to provide the much greater security of triple-key, triple-DES.
Date: April 30, 1999
Creator: Gass, Karl; Pierson, Lyndon G.; Robertson, Perry J.; Wilcox, D. Craig & Witzke, Edward L.
System: The UNT Digital Library
An Evaluation of the Parallel Shift-and-Invert Lanczos Method (open access)

An Evaluation of the Parallel Shift-and-Invert Lanczos Method

When the Lanczos method is used to compute eigenvalues, it is often restarted or used with the shift-and-invert scheme. The restarted scheme usually uses less memory but the shift-and-invert scheme is more robust. In addition, the shift-and-invert Lanczos method requires accurate solutions of a series of linear systems. Parallel software packages suitable for these linear systems are only started to become available. In this talk, we will present our evaluation of two such packages and briefly examine when it is necessary to use the shift-and-invert scheme.
Date: April 30, 1999
Creator: Wu, K. & Simon, H.
System: The UNT Digital Library
IC-Compatible Technologies for Optical MEMS (open access)

IC-Compatible Technologies for Optical MEMS

Optical Micro Electro Mechanical Systems (Optical MEMS) Technology holds the promise of one-day producing highly integrated optical systems on a common, monolithic substrate. The choice of fabrication technology used to manufacture Optical MEMS will play a pivotal role in the size, functionality and ultimately the cost of optical Microsystems. By leveraging the technology base developed for silicon integrated circuits, large batches of routers, emitters, detectors and amplifiers will soon be fabricated for literally pennies per part. In this article we review the current status of technologies used for Optical MEMS, as well as fabrication technologies of the future, emphasizing manufacturable surface micromachining approaches to producing reliable, low-cost devices for optical communications applications.
Date: April 30, 1999
Creator: Krygowski, T.W. & Sniegowski, J.J.
System: The UNT Digital Library
R-parity-violating production of single top squarks with R-parity-conserving decays. (open access)

R-parity-violating production of single top squarks with R-parity-conserving decays.

Single-top-squark production probes R-parity-violating extensions of the minimal supersymmetric standard model though the {lambda}{sub 3ij}{double_prime} coupling. For top-squark masses in the range 180-325 GeV, and {lambda}{sub 3ij}{double_prime} > 0.02-0.06, we show that discovery of the top squark is possible with 2 fb{sup {minus}1} of integrated luminosity at run II of the Fermilab Tevatron. The bound on {lambda}{sub 3ij}{double_prime} can be reduced by up to an order of magnitude with existing data from run I, and by two orders of magnitude at run II if the top squark is not found.
Date: April 30, 1999
Creator: Berger, E. L.; Harris, B. W. & Sullivan, Z.
System: The UNT Digital Library
Further Evidence for a Prepulse on OMEGA (open access)

Further Evidence for a Prepulse on OMEGA

None
Date: April 30, 1999
Creator: unknown
System: The UNT Digital Library