Project Tech Top study of lunar, planetary and solar topography Final report

Data acquisition techniques for information on lunar, planetary, and solar topograph

Influence of base and photoacid generator on deprotection blur in extreme ultraviolet photoresists and some thoughts on shot noise

A contact-hole deprotection blur metric has been used to monitor the deprotection blur of an experimental open platform resist (EH27) as the wt % of base and photoacid generator (PAG) were varied. A six times increase in base wt % is shown to reduce the size of successfully patterned 1:1 line-space features from 52 to 39 nm without changing deprotection blur. Corresponding isolated line edge roughness is reduced from 6.9 to 4.1 nm. A two times increase in PAG wt % is shown to improve 1:1 line-space patterning from 47 to 40 nm without changing deprotection blur or isolated line edge roughness. A discussion of improved patterning performance as related to shot noise and deprotection blur concludes with a speculation that the spatial distribution of PAG molecules has been playing some role, perhaps a dominant one, in determining the uniformity of photogenerated acids in the resists that have been studied. © 2008 American Vacuum Society

Knowledge and Perceptions of Electronic Cigarette Use among Pregnant Women

poster abstractThe association between maternal tobacco smoke exposure and restricted fetal growth has been well studied. However, the safety of electronic cigarettes (e-cigarettes) is quite controversial among pregnant women and the public. Research on the health effects of e-cigarette use during pregnancy is limited, particularly because of the health risks and ethical considerations. However, there is concern about the effects of the nicotine on fetal health from e-cigarettes. Some women’s beliefs about e-cigarettes are influenced by information that e-cigarettes may be beneficial as a way to decrease the number of tobacco cigarettes smoked. We conducted a systematic review of the literature to explore the knowledge and perceptions of e-cigarette use among pregnant women. Using pre-designated inclusion and exclusion criteria, relevant articles were located and reviewed searching PubMed, EMBASE, EBSCOhost, CINAHL Complete, and the reference lists of related articles. Full text, English language, peer-reviewed articles relevant to pregnant women’s knowledge and perceptions of e-cigarettes were reviewed. Of the thirty studies, six met the inclusion criteria. The following findings were common among the studies reviewed: 1) study participants had inaccurate information regarding the amount of nicotine in ecigarettes and the effects on the fetus; 2) e-cigarettes were perceived as safe alternatives and could be used for smoking cessation; 3) using e-cigarettes caused less negative side effects than traditional cigarettes; and 4) information obtained from the media about e-cigarettes was confusing for pregnant women. The findings support the need for healthcare providers to assess e-cigarette use among pregnant women and provide accurate information regarding e-cigarettes and the potential impact of use during pregnancy

Propagation of Vortex Electron Wave Functions in a Magnetic Field

The physics of coherent beams of photons carrying axial orbital angular momentum (OAM) is well understood and such beams, sometimes known as vortex beams, have found applications in optics and microscopy. Recently electron beams carrying very large values of axial OAM have been generated. In the absence of coupling to an external electromagnetic field the propagation of such vortex electron beams is virtually identical mathematically to that of vortex photon beams propagating in a medium with a homogeneous index of refraction. But when coupled to an external electromagnetic field the propagation of vortex electron beams is distinctly different from photons. Here we use the exact path integral solution to Schrodingers equation to examine the time evolution of an electron wave function carrying axial OAM. Interestingly we find that the nonzero OAM wave function can be obtained from the zero OAM wave function, in the case considered here, simply by multipling it by an appropriate time and position dependent prefactor. Hence adding OAM and propagating can in this case be replaced by first propagating then adding OAM. Also, the results shown provide an explicit illustration of the fact that the gyromagnetic ratio for OAM is unity. We also propose a novel version of the Bohm-Aharonov effect using vortex electron beams.Comment: 14 pages, 2 figures, submitted to Phys Rev

Fourier, Gauss, Fraunhofer, Porod and the Shape from Moments Problem

We show how the Fourier transform of a shape in any number of dimensions can be simplified using Gauss's law and evaluated explicitly for polygons in two dimensions, polyhedra three dimensions, etc. We also show how this combination of Fourier and Gauss can be related to numerous classical problems in physics and mathematics. Examples include Fraunhofer diffraction patterns, Porods law, Hopfs Umlaufsatz, the isoperimetric inequality and Didos problem. We also use this approach to provide an alternative derivation of Davis's extension of the Motzkin-Schoenberg formula to polygons in the complex plane.Comment: 21 pages, no figure

Changes in late adolescents’ voting intentions during the election campaign: Disentangling the effects of political communication with parents, peers and media

This article investigates the effects of political discussions with parents, political discussions with peers and exposure to political news during an election campaign on the voting intentions and behaviour of first-time voters. Longitudinal data collected in the Czech Republic are employed in the main analysis (N=223). Results show that young people who frequently discuss politics with their peers are characterized by higher voting intentions and subsequent electoral participation. On the other hand, political discussions with parents and exposure to political news have no such effects. Furthermore, although it does not have an impact on voting intentions, more frequent political discussions with parents predict increased frequency of political discussions with peers. Overall, our results underscore the importance of peers in late adolescents' political socialization

Focusing of atoms with strongly confined light potentials

Focusing of atoms with light potentials is studied. In particular, we consider strongly confined, cylindrical symmetric potential, and demonstrate their applications in both red and blue-detuned focusing of atoms. We also study the influence of aberrations, and find that a resolution of 1 nm should in principle be possible.Comment: 23 pages, 9 figures, Submitted to Optics Communication

Twill: A Hybrid Microcontroller-FPGA Framework for Parallelizing Single- Threaded C Programs

Increasingly System-On-A-Chip platforms which incorporate both micropro- cessors and re-programmable logic are being utilized across several fields ranging from the automotive industry to network infrastructure. Unfortunately, the de- velopment tools accompanying these products leave much to be desired, requiring knowledge of both traditional embedded systems languages like C and hardware description languages like Verilog. We propose to bridge this gap with Twill, a truly automatic hybrid compiler that can take advantage of the parallelism inherent in these platforms. Twill can extract long-running threads from single threaded C code and distribute these threads across the hardware and software domains to more fully utilize the asymmetric characteristics between processors and the embedded reconfigurable logic fabric. We show that Twill provides a sig- nificant performance increase on the CHStone benchmarks with an average 1.63 times increase over the pure hardware approach and an increase of 22.2 times on average over the pure software approach while reducing the area required by the reconfigurable logic by on average 1.73 times compared to the pure hardware approach

Disorder, Path Integrals and Localization

Anderson localization is derived directly from the path integral representation of quantum mechanics in the presence of a random potential energy function. The probability distribution of the potential energy is taken to be a Gaussian in function space with a given autocorrelation function. Averaging the path integral itself we find that the localization length, in one-dimension, is given by (E_{{\xi}}/{\sigma})(KE_{cl}/{\sigma}){\xi} where E_{{\xi}} is the "correlation energy", KE_{cl} the average classical kinetic energy, {\sigma} the root-mean-square variation of the potential energy and {\xi} the autocorrelation length. Averaging the square of the path integral shows explicitly that closed loops in the path when traversed forward and backward in time lead to exponential decay, and hence localization. We also show how, using Schwinger proper time, the path integral result can be directly related to the Greens function commonly used to study localization.Comment: 6 pages, no figure