Interference lithography is an emerging, technology that provides a means for achieving high resolution over large exposure areas (approximately 1 m{sup 2}) with virtually unlimited depth of field. One- and two-dimensional arrays of deep submicron structures can be created using near i-line wavelengths and standard resist processing. In this paper, we report on recent advances in the development of this technology, focusing, in particular, on how exposure latitude and resist profile scale with interference period We present structure width vs dose curves for periods ranging from 200 nm to 1 um, demonstrating that deep submicron structures can be generated with exposure latitudes exceeding 30%. Our experimental results are compared to simulations based on PROLITIV2.

Scanning force microscopy (SFM) was applied to direct nanoscale investigation of the mechanism of retention loss in ferroelectric thin films. Experiments were conducted by performing local polarization reversal within an individual grain with subsequent imaging of a resulting domain structure at various time intervals. A conductive SFM tip was used for domain switching and imaging in the SFM piezoresponse mode.

Preliminary work is presented on an effort to generate synthetic constitutive data for random composite materials. The long-ranged goal is to use the overall response determined from finite element simulations of representative volumes (RV) of the heterogeneous material to construct a homogenized constitutive model. A simple composite of a matrix containing polydispersed spheres was chosen as the first configuration to simulate. Here the accuracy of the numerical simulation tools is tested by determining effective elastic constants of the ordered elastic composite in which equal-sized spheres are arranged in each of three cubic lattice configurations. The resulting anisotropic effective elastic constant values agree with theoretical results to better than 10%, with typical agreement being better than 4%.

Significant progress has been made in developing a three-dimensional capability for predicting the mechanical response of rock over spatial and time scales of geologic interest to the Oil and Gas industry. An Advanced Computational Technology Initiative (ACTI) initiated three years ago to achieve such a computational technology breakthrough has made significant progress towards its goal by adapting and improving the unique advanced quasistatic finite element technology developed by Sandia National Laboratories to the mechanics applications important to exploration and production (E and P). This capability now gives the industry a powerful tool to help reduce risk on prospects, improve pre-project initial reserve estimates, and lower operating costs. Progress to date on this program is reported herein by presenting and discussing the enhancements and adaptations that have been made to the technology, with specific examples to illustrate their use on large E and P geomechanics problems.

Shock wave techniques have become a standard tool for studying the high pressure dynamic response of materials. An important advance in this field is the development of techniques for making detailed measurements of the time-resolved wave structure in shock and release waves. These techniques began with the development of stress wave gauges in the early 1960s and have evolved into a variety of high-resolution techniques being used in present shock physics applications. This paper provides a brief review of the development and use of time-resolved interferometer techniques for studying the high pressure dynamic response of materials. Applications of these techniques include studies of the initial compressive yield response of materials, plastic viscosity occurring during shock compression, measurements of compressive and tensile yield strength after passage of strong shock waves, and measurements of the kinetic properties of phase transitions. Dynamic material properties obtained from these measurements are important in developing predictive material models important to Science Based Stockpile Stewardship and in validating the equation of state and constitutive response of material models being used in a variety of applications. Examples are given which illustrate the importance of these measurements in current weapon physics and in other non-weapon applications. Prospects for extending …

When the detonation reaction-zone length, {eta}{sub r}, is short in comparison to the dimensions of the explosive piece being burnt, the detonation can be viewed as a propagating surface (or front) separating burnt from unburnt material. If the product of the shock curvature, {kappa} and {eta}{sub r} is small (i.e., the scaled shock curvature satisfies the {vert_bar}{kappa}{eta}{sub r}{vert_bar} {much_lt} 1), then to leading order the speed of this surface, D{sub n}({kappa}) is a function only of {kappa}. It is in this limit that the original version of the asymptotic detonation front theory, called detonation shock dynamics (DSD), derives the propagation law, D{sub n}({kappa}). In this lecture, the authors compare D{sub n}({kappa})-theory with the results obtained with high-resolution direct numerical simulations (DNS), and then use the DNS results to guide the development of extended asymptotic front theories with enhanced predictive capabilities.

This paper is on the operation principles of the Visible Light Photon Counters (VLPCs), application to high luminosity-high multiplicity tracking for High Energy Charged Particle Physics, and application to Medical Imaging and Particle Astrophysics. The VLPCs as Solid State Photomultipliers (SSPMS) with high quantum efficiency can detect down to single photons very efficiently with excellent time resolution and high avalanche gains.

This experiment demonstrates detection of cosmic ray tracks by using Scintillating fiber planes and multi-anode photomultipliers (MA-PMTs). In a laboratory like this, cosmic rays provide a natural source of high-energy charged particles which can be detected with high efficiency and with nanosecond time resolution.

Oxide inclusions form in welds because of deoxidation reactions in the weld pool. These inclusions control the weld microstructure development. Thermodynamic and kinetic calculation of oxidation reaction can describe inclusion characteristics such as number density, size, and composition. Experimental work has shown that fluid-flow velocity gradients in the weld pool can accelerate inclusion growth by collision and coalescence. Moreover, fluid flow in welds can transport inclusions to different temperature regions that may lead to repeated dissolution and growth of inclusions. These phenomena are being studied with the help of computational coupled heat transfer, fluid-flow, thermodynamic, and kinetic models. The results show that the inclusion formation in steel welds can be described as a function of the welding processes, process parameters, and steel composition.

Experimental Breeder Reactor-II (EBR-II), an experimental sodium cooled fast breeder reactor located at Argonne National Laboratory-West (ANL-W), was shut down in 1994, and has since been defueled in preparation for final plant closure. Approximately 100,000 gallons of liquid sodium is contained in the primary and secondary cooling systems of the EBR-II plant. The liquid sodium must be drained from the reactor systems during closure of the plant to place the reactor plant in an industrially and radiologically safe condition for long term storage or dismantlement. Because the liquid sodium is a listed waste under the Resource Conservation Recovery Act (RCRA), it is not suitable for disposal. It therefore must be transferred to the Sodium Process Facility (SPF), which is located approximately nine hundred feet from the reactor complex, where it will be processed into a non-reactive form, suitable for land disposal in Idaho. To facilitate this transfer, a heated pipeline for carrying liquid sodium metal from EBR-II to the SPF was designed and installed. The SPF was originally designed and built to process primary sodium from the Fermi-1 reactor. The sodium is stored at ANL-W in 55 gallon drums. Design of the SPF did not originally accommodate processing of EBR-II …

Development of high-temperature superconductor technology will make possible the design and fabrication of smaller, lighter, and more efficient power devices such as motors, generators, transformers, transmission cables, and fault-current limiters. A prototype fault-current limiter, a 200-hp motor, and a 50-m-long transmission cable have already been demonstrated using Ag-clad Bi-2223 superconductor tapes. We have recently enhanced the transport current properties of long lengths of multifilament Ag-clad Bi-2223 tapes through increased packing density of precursor powder, improved mechanical deformation, optimization of conductor design, and adjusted cooling rate. These improved processing parameters had a pronounced effect on the transport critical current of the super-conducting tapes. Our improvements are briefly discussed and their implications are assessed in this paper.

The possibilities of a ring cooler stage in a muon collider are explored. A basic design is examined both with analytic calculations and simulation of the evolution of beam phase space.

The azimuthal dependence of second- and third-order coupling are used to measure the relative contributions of each to direct third harmonic generation with efficiencies up to 6%. The values of {xi}{sub ij}{sup (3)} are measured.

The technology of room-temperature-setting phosphate ceramics or Ceramicrete{trademark} technology, developed at Argonne National Laboratory (ANL)-East is being used to treat and dispose of low-level mixed wastes through the Department of Energy complex. During the past year, Ceramicrete{trademark} technology was implemented for field application at ANL-West. Debris wastes were treated and stabilized: (a) Hg-contaminated low-level radioactive crushed light bulbs and (b) low-level radioactive Pb-lined gloves (part of the MWIR {number_sign} AW-W002 waste stream). In addition to hazardous metals, these wastes are contaminated with low-level fission products. Initially, bench-scale waste forms with simulated and actual waste streams were fabricated by acid-base reactions between mixtures of magnesium oxide powders and an acid phosphate solution, and the wastes. Size reduction of Pb-lined plastic glove waste was accomplished by cryofractionation. The Ceramicrete{trademark} process produces dense, hard ceramic waste forms. Toxicity Characteristic Leaching Procedure (TCLP) results showed excellent stabilization of both Hg and Pb in the waste forms. The principal advantage of this technology is that immobilization of contaminants is the result of both chemical stabilization and subsequent microencapsulation of the reaction products. Based on bench-scale studies, Ceramicrete{trademark} technology has been implemented in the fabrication of 5-gal waste forms at ANL-West. Approximately 35 kg of real …

The subject of this paper is the development of mathematical foundations for a theory of simulation. Sequentially updated cellular automata (sCA) over arbitrary graphs are employed as a paradigmatic framework. In the development of the theory, the authors focus on the properties of causal dependencies among local mappings in a simulation. The main object of and study is the mapping between a graph representing the dependencies among entities of a simulation and a representing the equivalence classes of systems obtained by all possible updates.

Planar, micron-scale ellipses patterned from 700A-thick Co films exhibit nearly complete suppression of hysteresis when magnetized in- plane along their short axes. Using a combination of Magnetic Force Microscopy and Vibrating Sample Magnetometry, we find that the suppression of hysteresis is associated with the continuous deformation of a dipole field configuration. The presence of hysteresis for in-plane, long-axis magnetization is associated with transitions between topologically inequivalent configurations.

This paper presents several upper and lower bounds for the number-of-bits required for solving a classification problem, as well as ways in which these bounds can be used to efficiently build neural network chips. The focus will be on complexity aspects pertaining to neural networks: (1) size complexity and depth (size) tradeoffs, and (2) precision of weights and thresholds as well as limited interconnectivity. They show difficult problems-exponential growth in either space (precision and size) and/or time (learning and depth)-when using neural networks for solving general classes of problems (particular cases may enjoy better performances). The bounds for the number-of-bits required for solving a classification problem represent the first step of a general class of constructive algorithms, by showing how the quantization of the input space could be done in O (m{sup 2}n) steps. Here m is the number of examples, while n is the number of dimensions. The second step of the algorithm finds its roots in the implementation of a class of Boolean functions using threshold gates. It is substantiated by mathematical proofs for the size O (mn/{Delta}), and the depth O [log(mn)/log{Delta}] of the resulting network (here {Delta} is the maximum fan in). Using the fan in …

{l_brace}222{r_brace}MgO/Cu is one of the most extensively characterized ceramic/metal interfaces, in view of the atom probe field ion microscopy, Z-contrast Scanning Transmission Electron Microscopy (STEM), and spatially resolved Electron energy loss spectroscopy (EELS) measurements performed by the present authors, as well as the high resolution electron microscopy (HREM) of this system by others. Atomistic simulations with local density functional theory (LDFT) and Molecular Dynamics (MD) have been performed to gain additional insight into the structure of this interface. This presentation describes an interface interatomic potential for {l_brace}222{r_brace}MgO/Cu derived from LDFT total energy calculations, and its application to structural properties, including the terminating species, the absence of dislocation standoff, and the symmetry of the interfacial dislocation network.

Observations made more than ten years ago showed that SiC could be made amorphous at cryogenic temperatures by in-situ 300kV electron irradiation. However, high voltage electron microscope (HVEM) results indicate a threshold voltage of 725 kV for amorphization of SiC at 140 K. In addition, a recent review exposes the considerable uncertainty in the literature regarding displacement energies for SiC. Therefore, further experiments have been performed in a Philips CM30 (LaB{sub 6} cathode) with a Gatan double-tilt cooling holder in an attempt to determine the threshold voltage for amorphization at {approximately} 140 K. Sintered {alpha}-SiC (defected 6H polytype), beam direction B = <11{bar 2}0>, and probes containing {approximately} 75 nA in {approximately} 0.5 {micro}m, were used. Amorphization occurred in <10 min at 300 kV and after {approximately} 60 min at 180 kV; visible darkening occurred at lower voltages and doses. Similar behavior occurred for B = [0001]. The critical dose for amorphization was measured as a function of accelerating voltage. Probe current profiles were measured by post-specimen scanning (CM30 SCIM mode with 100 {micro}m diameter Gatan STEM detector) images of the focused probes positioned in a hole, and probe currents were measured from the exposure time, which had previously been …

The authors discuss the motivation for resummation of the effects of initial-state soft gluon radiation, to all orders in the strong coupling strength, for processes in which the near-threshold region in the partonic subenergy is important. The author summarizes the method of perturbative resummation and its application to the calculation of the total cross section for top quark production at hadron colliders. Comments are included on the differences between the treatment of subleading logarithmic terms in this method and in other approaches.

The authors present the results of MD modeling on the structural properties of grain boundaries (GB) in thin polycrystalline films. The transition from crystalline boundaries with low mismatch angle to amorphous boundaries is investigated. It is shown that the structures of the GBs satisfy a thermodynamical criterion suggested in a cited reference. The potential energy of silicon atoms is closely related with a geometrical quantity -- tetragonality of their coordination with their nearest neighbors. A crossover of the length of localization is observed to analyze the crossover of the length of localization of the single electron states and properties of conductance of the thin polycrystalline film at low temperature. They use a two-dimensional Anderson localization model, with the random one site electron charging energy for a single grain (dot), random non-diagonal matrix elements, and random number of connections between the neighboring grains. The results on the crossover behavior of localization length of the single electron states and characteristic properties of conductance are presented in the region of parameters where the transition from an insulator to a conductor regimes takes place.

We present an analysis of the recent solar neutrino data from the five experiments using Bayesian approach. We extract quantitative and easily understandable information pertaining to the solar neutrino problem. The probability distributions for the individual neutrino fluxes and, discrepancy distribution for B and Be fluxes, which include theoretical and experimental uncertainties have been extracted. The analysis carried out assuming that the neutrinos are unaltered during their passage from the sun to earth, clearly indicate that the observed PP flux is consistent with the 1995 standard solar model predictions of Bahcall and Pinsonneault within 2{sigma} (standard deviation), whereas the {sup 8}B flux is down by more than 12{sigma} and the {sup 7}Be flux is maximally suppressed. We also deduce the experimental survival probability for the solar neutrinos as a function of their energy in a model-independent way. We find that the shape of that distribution is in qualitative agreement with the MSW oscillation predictions.

Subsurface Disposal (SDA) of the Radioactive Waste Management Complex serves as the low level waste burial ground at the Idaho National Engineering and Environmental Laboratory (INEEL). The low level wastes are buried in trenches, pits, and soil vaults in surficial sediments. A closure/post-closure plan must be written prior to closure of the SDA. The closure plan for the facility must include a design for an engineered barrier closure cover that will meet all applicable regulatory requirements. This paper describes the approach being followed at the INEEL to choose an appropriate cover design for the SDA closure. Regulatory requirements and performance objectives potentially applicable to closure of the SDA were identified. Technical issues related to SDA closure were identified from a literature search of previous arid site engineered barrier studies and from previous SDA closure cover evaluations. Five engineered barrier conceptual design alternatives were identified: (1) a bio/capillary barrier cover, (2) a thin soil cover, (3) a thick soil cover, (4) a Resource Conservation and Recovery Act cover, and (5) a concrete sealed surface cover. Two of these designs were chosen for in situ hydraulic testing, rather than all five, in order to maximize the amount of information generated relative to …

Laboratory tests on 0.5 meter scale blocks of Topopah Spring tuff were performed to determine fluid flow and mechanical behavior of samples containing fractures. Results include data for a comprehensive set of flow measurements through a rock sample containing a horizontally oriented fracture at uniaxial stress conditions up to 8 MPa at room temperature. Directional channeling, rather than mean fracture aperture, controls the flow. On the time scale of these experiments, inhibition is negligible.