Development of nonflammable coating for polycarbonate Final report

Sodium and potassium silicates applied to polycarbonates to provide nonflammable coating

Polymer Dissolution Model: An Energy Adaptation Of The Critical Ionization Theory

The current scale of features size in the microelectronics industry has reached the point where molecular level interactions affect process fidelity and produce excursions from the continuum world like line edge roughness (LER). Here we present a 3D molecular level model based on the adaptation of the critical ionization (CI) theory using a fundamental interaction energy approach. The model asserts that it is the favorable interaction between the ionized part of the polymer and the developer solution which renders the polymer soluble. Dynamic Monte Carlo methods were used in the current model to study the polymer dissolution phenomenon. The surface ionization was captured by employing an electric double layer at the interface, and polymer motion was simulated using the Metropolis algorithm. The approximated interaction parameters, for different species in the system, were obtained experimentally and used to calibrate the simulated dissolution rate response to polymer molecular weight and developer concentration. The predicted response is in good agreement with experimental dissolution rate data. The simulation results support the premise of the CI theory and provide an insight into the CI model from a new prospective. This model may provide a means to study the contribution of development to LER and other related defects based on molecular level interactions between distinct components in the polymer and the developer.Chemical Engineerin

Nonthermal hard X-ray excess in the Coma cluster: resolving the discrepancy between the results of different PDS data analyses

The detection of a nonthermal excess in the Coma cluster spectrum by two BeppoSAX observations analyzed with the XAS package (Fusco-Femiano et al.) has been disavowed by an analysis (Rossetti & Molendi) performed with a different software package (SAXDAS) for the extraction of the spectrum. To resolve this discrepancy we reanalyze the PDS data considering the same software used by Rossetti & Molendi. A correct selection of the data and the exclusion of contaminating sources in the background determination show that also the SAXDAS analysis reports a nonthermal excess with respect to the thermal emission at about the same confidence level of that obtained with the XAS package (~4.8sigma). Besides, we report the lack of the systematic errors investigated by Rossetti & Molendi and Nevalainen et al. taking into account the whole sample of the PDS observations off the Galactic plane, as already shown in our data analysis of Abell 2256 (Fusco-Femiano, Landi & Orlandini). All this eliminates any ambiguity and confirms the presence of a hard tail in the spectrum of the Coma cluster.Comment: 12 pages, 2 figures. Accepted for publication in ApJ Letter

Combining visibilities from the Giant Meterwave Radio Telescope and the Nancay Radio Heliograph: High dynamic range snapshot images of the solar corona at 327 MHz

We report first results from an ongoing program of combining visibilities from the Giant Meterwave Radio Telescope (GMRT) and the Nancay Radio Heliograph (NRH) to produce composite snapshot images of the sun at meter wavelengths. We describe the data processing, including a specific multi-scale CLEAN algorithm. We present results of a) simulations for two models of the sun at 327 MHz, with differing complexity b) observations of a complex noise storm on the sun at 327 MHz on Aug 27 2002. Our results illustrate the capacity of this method to produce high dynamic range snapshot images when the solar corona has structures with scales ranging from the image resolution of 49" to the size of the whole sun. We find that we cannot obtain reliable snapshot images for complex objects when the visibilities are sparsely sampled.Comment: Accepted for publication in Astronomy & Astrophysics. Version with high resolution figures available from ftp://ftp.iucaa.ernet.in/in.coming/gmrtnr

Outer jet X-ray and radio emission in R Aquarii: 1999.8 to 2004.0

Chandra and VLA observations of the symbiotic star R Aqr in 2004 reveal significant changes over the three to four year interval between these observations and previous observations taken with the VLA in 1999 and with Chandra in 2000. This paper reports on the evolution of the outer thermal X-ray lobe-jets and radio jets. The emission from the outer X-ray lobe-jets lies farther away from the central binary than the outer radio jets, and comes from material interpreted as being shock heated to ~10^6 K, a likely result of collision between high speed material ejected from the central binary and regions of enhanced gas density. Between 2000 and 2004, the Northeast (NE) outer X-ray lobe-jet moved out away from the central binary, with an apparent projected motion of ~580 km s^-1. The Southwest (SW) outer X-ray lobe-jet almost disappeared between 2000 and 2004, presumably due to adiabatic expansion and cooling. The NE radio bright spot also moved away from the central binary between 2000 and 2004, but with a smaller apparent velocity than of the NE X-ray bright spot. The SW outer lobe-jet was not detected in the radio in either 1999 or 2004. The density and mass of the X-ray emitting material is estimated. Cooling times, shock speeds, pressure and confinement are discussed.Comment: 23 pages, 8 figure

A Note on Encodings of Phylogenetic Networks of Bounded Level

Driven by the need for better models that allow one to shed light into the question how life's diversity has evolved, phylogenetic networks have now joined phylogenetic trees in the center of phylogenetics research. Like phylogenetic trees, such networks canonically induce collections of phylogenetic trees, clusters, and triplets, respectively. Thus it is not surprising that many network approaches aim to reconstruct a phylogenetic network from such collections. Related to the well-studied perfect phylogeny problem, the following question is of fundamental importance in this context: When does one of the above collections encode (i.e. uniquely describe) the network that induces it? In this note, we present a complete answer to this question for the special case of a level-1 (phylogenetic) network by characterizing those level-1 networks for which an encoding in terms of one (or equivalently all) of the above collections exists. Given that this type of network forms the first layer of the rich hierarchy of level-k networks, k a non-negative integer, it is natural to wonder whether our arguments could be extended to members of that hierarchy for higher values for k. By giving examples, we show that this is not the case

Ordering block copolymers

A method for ordering block copolymers including forming a first layer having a first preference mode; and providing a reactive agent in selected regions of the first layer that modifies the selected regions to a second preference mode, wherein the selected regions define other regions of the first layer retaining the first preference mode thereby forming an alignment layer for block copolymers.Board of Regents, University of Texas Syste

Polymer Bound Photobase Generators And Photoacid Generators For Pitch Division Lithography

The semiconductor industry is pursuing several process options that provide pathways to printing images smaller than the theoretical resolution limit of 193 nm projection scanners. These processes include double patterning, side wall deposition and pitch division. Pitch doubling lithography (PDL), the achievement of pitch division by addition of a photobase generator (PBG) to typical 193 nm resist formulations was recently presented. 1 Controlling the net acid concentration as a function of dose by incorporating both a photoacid generator (PAG) and a PBG in the resist formulation imparts a resist dissolution rate response modulation at twice the frequency of the aerial image. Simulation and patterning of 45 nm half pitch L/S patterns produced using a 90 nm half pitch mask were reported. 2 Pitch division was achieved, but the line edge roughness of the resulting images did not meet the current standard. To reduce line edge roughness, polymer bound PBGs and polymer bound PAGs were investigated in the PDL resist formulations. The synthesis, purification, analysis, and functional performance of various polymers containing PBG or PAG monomers are described herein. Both polymer bound PBG with monomeric PAG and polymer bound PAG with monomeric PBG showed a PDL response. The performance of the polymer bound formulations is compared to the same formulations with small molecule analogs of PAG and PBG.Chemical Engineerin

Rocket calibration of the Nimbus 6 solar constant measurements

Total solar irradiance was observed simultaneously outside the earth's atmosphere by three types of absolute cavity radiometers and duplicates of four of the Nimbus 6 Earth Radiation Budget (ERB) solar channels in a June 1976 sounding rocket experiment. The preliminary average solar constant result from the cavity radiometers is 1367 Wm (-2) with an uncertainty of less than + or - 0.5% in S.I. units. The duplicate ERB channel 3 on the rocket gave a value of 1389 Wm (-2) which agreed exactly with the Nimbus 6 ERB channel 3 measurement made simultaneously with the rocket flight