Session EB - Poster Session.
POSTER session, Thursday afternoon, November 06
Masonboro, HISR

[EB.001] A Mechanical Theory of Heat

In radiation mechanics, heat is defined as the part of energy a mechanically isolated system gains or loses due to the absorption and emission of photons. It is proved that the energy of a mechanically isolated system is actually in random fluctuation. The theory of heat is outlined by the following conclusions: 1) Thermal vibrations of atoms are provoked by the magnetic interaction between the outermost electrons of adjacent atoms. 2) Magnitudes of spin angular momentums of the outermost electrons and the distance between adjacent atoms determine the intensity of thermal vibrations. 3) Thermal vibration equilibrium indicates a kind of force balances among the gravitational and deformational forces between adjacent atoms and the magnetic force between the outermost electrons of adjacent atoms. 4) Heat radiation, by which photons are emitted and absorbed, is actually the only way of heat transfer, and calories are truly indestructible substances, the photons. 5) Temperature is always an environment-dependent relative parameter.

[EB.002] Model for Spiral Galaxys Rotation Curves

A model of spiral galaxy dynamics is proposed. An expression describing the rotation velocity of particles v in a galaxy as a function of the distance from the center r (RC) is developed. The resulting, intrinsic RC of a galaxy is Keplerian in the inner bulge and rising in the disk region without modifying the Newtonian gravitational potential (MOND) and without unknown dark matter. The v^2 is linearly related to r of the galaxy in part of the rapidly rising region of the HI RC (RRRC) and to r^2 in another part of the RRRC. The r to discontinuities in the surface brightness versus r curve is related to the 21 cm line width, the measured mass of the central supermassive black hole (SBH), and the maximum v^2 in the RRRC. The distance to spiral galaxies can be calculated from these relationships that tightly correlates with the distance calculated using Cepheid variables. Differing results in measuring the mass of the SBH from differing measurement procedures are explained. This model is consistent with previously unexplained data, has predicted new relationships, and suggests a new model of the universe. Full text: http://web.infoave.net/\simscjh.

[EB.003] Asymmetry Measurements in the Reaction L + p\longrightarrow \Lambda + \nu_L Near Threshold

We calculate the asymmetry,(d\sigma(left)/dØmega-d\sigma(right)/dØmega)/(d\sigma(left)/dØmega + d\sigma(right)/dØmega) for the reaction L + p\longrightarrow \Lambda + \nu_L where L is a muon or tau lepton. This reaction is normally suppressed in electron measurements because the projector,1-\gamma_5 acting on a relativistic right handed lepton yields zero but gives finite results for the muon and tau lepton cases near threshold. Thus this reaction might form the basis of a possible experiment particularly for muons. We discuss these possibilities and what might be learned from such a measurement.

[EB.004] A Computational Investigation of Starburst Galaxies

In order to understand our own origins we need to understand how the elements which make up our planet and our own bodies are created and distributed throughout the Galaxy. Understanding the starburst process is a vital part of this endeavor. A starburst galaxy is one in which a large number of massive stars form relatively close together in time and space. This leads, after a short time (a few million years), to a burst of supernovae (SN) physically close to one another. The result is an overlapping wake of explosive energy which drives into the galactic background mechanically reshaping it and enriching it with heavy elements. The cooler, denser, ambient Inter Stellar Medium (ISM) is swept-up and carried along by the hotter SN-ejecta . The theoretical treatment of all the interacting processes of the starburst requires computer simulation.

We are using a 3D parallel version of the VH-1 hydrodynamics code to model starburst galaxies on our departments newly constructed 16 processor Linux cluster.. The code models hydrodynamics, gravity, and radiative cooling. A mass/energy distributions based on observations is used. The results of this model will be used to create visible and X-Ray spectra for comparison with observations from the Chandra and Hubble space telescopes. Preliminary results will be reported from simulations currently underway.

[EB.005] The Study of a Suspended Optic

The dynamics of a damped driven three-dimensional pendulum were studied to better understand the motion of LIGO (Laser Interferometer Gravitational-Wave Observatory) suspended optics. The optics are suspended by wires to the top of a cage and are actively controlled for precise positioning. We made a model suspended optic without a control loop. We drove the suspension point of the model at various frequencies and analyzed the resultant motion. The End-to-end program (LIGO numerical simulator) replicates various interferometer components. We simulated our experiment with E2e using the dimensions of the model and the experimentally determined natural frequencies and quality (Q) factors. The simulation reproduced our experimental data accurately. We observed energy transfer from the pendular (at 1.0 Hz) to the pitch (at 3.2 Hz) degree of freedom. The transfer function of the simulation shows that as the pendular Q factor is decreased the pitch peak increases, indicating that more of the pendular energy is transferred to the pitch motion. We are now working with the control loop engaged to simulate the actual LIGO suspended optics.

[EB.006] Evidence of Organophosphonate Self-Assembled Monolayers on GaAs and GaN

Self-assembled monolayers (SAMs) of organic molecules on metal and semiconductor surfaces has been shown to have uses such as soft lithography, activation for the adhesion of biological and other materials, and alteration of electrical and optical properties. To date, the only self-assembly of this type that has been reported on III-V semiconductors has been the observation of alkane thiol monolayers on GaAs by the group at Penn State. We have discovered an alternate system using octadecylphosphonic acid (ODPA). Monolayers of ODPA were formed by immersion of GaAs or GaN in a 0.5 mM solution of ODPA in 2-propanol for more than one hour. The SAMs were observed by analysis of surface wetting and XPS. These SAMs are stable in atmosphere for more than six months and can be selectively deposited using microcontact printing. We have demonstrated the use of these monolayers for both the selective electrodeposition of copper and selective dewetting of a polymer on GaAs.

[EB.007] Low energy charge-transfer in B5+ + H2 collisions*

Electron capture from molecular hydrogen is an important phenomenon in the upper atmosphere. Molecular target is much more complex than the atomic target and consequently there are not very many calculations available. By freezing the molecular details of the target molecular hydrogen, Saha and Kumar [1] have recently calculated semi classically the state-selective cross sections by fully and partially stripped ions from H2. This provides a convenient way to calculate the capture cross sections when the important couplings are confined into a small region of inter nuclear separation (R) at comparatively large R values so that the internal structure of the molecule is not very involved. The calculated cross sections agree nicely with the experimental results even at low energies. This motivated us to study the following process Be5+ + H2----‡ Be4+ (nl) +H2+ using the semi classical, impact parameter, close coupling method based on a molecular expansion augmented with the plane wave translation factor. The detail of our calculation will be reported along with a comparison with the experimental results.

[1] B. C. Saha and A. Kumar, journal of molecular structure (Theochem) 487, 11 (2999).;A. Kumar and B. C. Saha, Phys. Rev. A 59,1273 (1999).

* Supported by Research Corporation, NASA, NSF-CREST and Army High Performance research Center

[EB.008] Theoretical investigation of aberrations upon ametropic human eyes

The human eye aberrations are important for visual acuity and ophthalmic diagnostics and surgical procedures. Reported monochromatic aberration data of the normal 20/20 human eyes are scarce. There exist even fewer reports of the relation between ametropic conditions and aberrations. We theoretically investigate the monochromatic and chromatic aberrations of human eyes for refractive errors of –10 to +10 diopters. Schematic human eye models are employed using optical design software for axial, index, and refractive types of ametropia.

[EB.009] The Magneto-Rotational Instability in Core-Collapse Supernovae

We present numerical magnetohydrodynamic simulations of the effect of weak magnetic field on idealized Standing Accretion Shocks (SAS) that arise in classical core-collapse supernovae, wherein an expanding shock front stalls at a radius of order 200 km and remains quite stationary for a relatively long period of time (300 ms or more). In the models we present here, specific angular momentum is fixed at the outer boundary where outer core material is free-falling onto the stalled accretion shock. To ensure that the initial seed magnetic field has a poloidal component, a necessary condition for the possible growth of magneto-rotational instability (MRI), we use a weak dipole magnetic field. Our fully dynamical simulations of this interaction of rotation and the magnetic field in SAS in the context of core-collapse supernovae, show a substantial exponential growth of the magnetic field energy that can exceed 8 orders of magnitude, and which dominates the linear growth process of ``field-line wrapping''. This is characteristic of MRI growth in our models.

[EB.010] Magnetic Rayleigh-Taylor Instability in Pulsar Wind Nebulae

We present two-dimensional numerical simulations of the development of the Rayleigh-Taylor (RT) instability at the interface between an expanding pulsar wind nebula (PWN) and the swept up shell of supernova ejecta. The simulations include the presence of magnetic field which is supposed to be above equipartition in the PWN, and were done in a proper special relativistic regime. The RT instability in presence of magnetic field is revised in the framework of the PWN expansion, and a stability condition is derived. Simulations show that even a very weak magnetic field can suppress the formation of RT fingers. This has important implications in the correct understanding of the local physical conditions in PWN. This work suggests that efficient radiative cooling in the ejecta shell is required to justify the observed morphology in the Crab Nebula.

[EB.011] Adsorption Isotherm Studies of Methyl Bromide on MgO

The adsorption of methyl bromine onto highly-uniform magnesium oxide powder was studied using a high-precision computer-controlled gas adsorption system. Methyl bromide was condensed onto the MgO substrate at temperatures between 165 K and 180 K. The layering behavior, iosthermal compressibility, and isosteric heat of adsorption were determined. Isotherms will be presented and future work discussed. TEB research sponsored by the Department of Energy EPSCOR Grant No. DE-FG02-01ER45895. JZL research sponsored by start-up funds from the University of Tennessee - Knoxville and by the Division of Materials Sciences, Office of Basic Energy Sciences, U.S. Department of Energy, under contract No. DE-AC05-00OR22725 with Oak Ridge National Laboratory, managed and operated by UT-Battelle, LLC.

[EB.012] Adeno-associated virus type 2 binding study on model heparan sulfate surface

Understanding the mechanisms involved in virus infections is useful in its application in areas such as gene therapy, drug development and delivery, and biosensors. In collaboration with UNC Gene Therapy Center and School of Pharmacy, we are specifically looking at the interaction between human parvovirus adeno-associated virus type 2 (AAV2), a potential viral vector, and heparan sulfate proteoglycan (HSPG), a known cell surface receptor for AAV2. Recent development in glycobiology has shown that some protein-polysaccharide binding is sugar sequence dependent. Heparan sulfate (HS) is a polysaccharide chain of sulfated iduronic/glucuronic and sulfate glucosamine residues and can be differentiated into sequence specific structures by enzymes. These enzymatic modifications, known as heparan sulfate sulfotransferase modified modifications, have been shown to change the biological nature of heparan sulfate such as specific binding to proteins and viruses. For understanding HS-assisted viral infection mechanisms, we are interested in investigating the binding affinity and stability of AAV to different HS structures. We have developed a model heparan sulfate surface in which AAV adsorption studies are done and analyzed using the atomic force microscope (AFM). In addition, a miniArray assay has been created to facilitate to this study. Adsorption studies are done in 4 ƒŬl wells with approximately 3 mm2 reaction areas which minimize sample use and waste.

[EB.013] Exact Kinetic Energy Density Functional for Fermions in a Box

We are able to construct an exact kinetic energy density functional for fermions in an infintely deep potential well. Details of our procedure and some applications are presented.

[EB.014] Progress on Developing a Pulsed FORT Using IR Radiation from a Free Electron Laser*

We report on the progress of experiments under development to use the free electron laser at Jefferson National Laboratory to spatially confine ultracold rubidium atoms using the optical dipole force. To date, almost all far-off-resonance traps (FORT) for confining ultracold atoms have used cw laser light. But pulsed laser light, for which the light-on duty-cycle is quite low, has a number of advantages. A pulsed FORT can be applied to precision measurements experiments which demand minimal external perturbations. In addition, confinement of species requiring blue light-which is easier to produce using pulsed lasers than using cw sources- will be facilitated. Finally, with free electron lasers capable of producing kiloWatts of average power, we envision the ability to produce traps whose spatial extent is considerably larger than is currently achievable with tabletop cw laser sources.

*Supported in part by the National Science Foundation, grant no. INT-0225869.

[EB.015] Spectroscopy of Stimulated Raman Scattering and Raman Laser Development of Barium Nitrate

Stimulated Raman scattering (SRS) in solid-state materials has been widely studied to generate new optical frequencies. SRS allows the laser frequency to be changed by a specific frequency shift that is determined by the spontaneous Raman spectra of a nonlinear laser material. Crystalline barium nitrate has a strong Raman vibrational mode at a frequency of ~1047 cm-1 at room temperature. The first and second stokes of barium nitrate were at ~563 nm and ~599 nm by exciting with a frequency-doubled Nd:YAG laser with ~6 ns pulse width. Laser performance of barium nitrate was carried out using a plano-concave laser cavity. An uncoated barium nitrate crystal (10 x 10 x 5 mm3, Crystal Associates) was pumped longitudinally along the 5-mm dimension in a cavity consisting of a curved output mirror (r = 1m, T = 23.3563 nm, R=98.5563 nm, T = 12.9threshold of barium nitrate Raman laser at 563 nm were ~13and ~7 mJ. The details of SRS spectroscopy and laser performance of barium nitrate will be discussed.

[EB.016] Nonlinear Optical Properties of Cadmium Telluride Nanocrystals

The high nonlinear figure of merit and large nonlinear refraction of chalcogenide semiconductor nanocrystals are of great interest for nonlinear optical applications. Ideal optical properties of nonlinear materials for nonlinear optical applications are an ultrafast optical response, a high nonlinear figure of merit; and a wide dynamic range of laser wavelength. Cadmium chalcogenide (CdTe, CdSe, and CdS) semiconductor nanocrystals were synthesized using with a chemical colloidal reaction technique. The third-order nonlinear susceptibility of CdTe nanocrystal quantum dots in toluene was measured by a single beam Z-scan and I-scan spectroscopy. The average diameter of the nanocrystal quantum dots was \sim5 nm with the first exciton absorption peak at \sim665 nm and the optical band edge at \sim690 nm. The nonlinear absorption and nonlinear refraction were evaluated from the normalized transmittance with a closed- aperture and with an open-aperture, respectively. The nonlinear refraction coefficient of CdTe in toluene (\sim8 x 10-5 mol/L) was estimated to be \sim -1 x 10-13 m2/W. The nonlinear absorption of CdTe was at least less than the fluctuations (\sim0.01) of normalized transmittance. With conservative evaluation, the nonlinear FOM of CdTe in toluene was estimated to be 200 at \sim800 nm. The quantum confinement and the surface trapped state effects of nanocrystals are the possible origins of their large optical nonlinearity.

Part E of program listing