Finite-Element Simulations of Light Propagation through Circular Subwavelength Apertures

Light transmission through circular subwavelength apertures in metallic films with surrounding nanostructures is investigated numerically. Numerical results are obtained with a frequency-domain finite-element method. Convergence of the obtained observables to very low levels of numerical error is demonstrated. Very good agreement to experimental results from the literature is reached, and the utility of the method is demonstrated in the investigation of the influence of geometrical parameters on enhanced transmission through the apertures

Fast simulation method for parameter reconstruction in optical metrology

A method for automatic computation of parameter derivatives of numerically computed light scattering signals is demonstrated. The finite-element based method is validated in a numerical convergence study, and it is applied to investigate the sensitivity of a scatterometric setup with respect to geometrical parameters of the scattering target. The method can significantly improve numerical performance of design optimization, parameter reconstruction, sensitivity analysis, and other applications

Mesothelial reaction to asbestos and other irritants after intraperitoneal injection

ArticleThe original publication is available from http://www.samj.org.zaBibliographyTen groups of rats were injected intraperitoneally with one of the following suspensions; standard reference crocidolite; acid treated crocidolite; crocidolite + iron oxide; crocidolite + silica; iron oxide; silica; long fiber crocidolite; short fiber crocidolite; long fiber glass and short fiber glass. Two rats from each group were killed at 45, 90, 150, 240 and 330 days respectively, and the pathology induced by the different suspensions was studied histologically at each time interval. No evidence in support of the chemical induction theory of mechanical irritation theory in the pathogenesis of peritoneal mesotheliomas could be found, although all the suspensions except iron oxide caused a reactive mesothelium.Publishers' versio

Expansion of a coherent array of Bose-Einstein condensates

We investigate the properties of a coherent array containing about 200 Bose-Einstein condensates produced in a far detuned 1D optical lattice. The density profile of the gas, imaged after releasing the trap, provides information about the coherence of the ground-state wavefunction. The measured atomic distribution is characterized by interference peaks. The time evolution of the peaks, their relative population as well as the radial size of the expanding cloud are in good agreement with the predictions of theory. The 2D nature of the trapped condensates and the conditions required to observe the effects of coherence are also discussed.Comment: 4 pages, 3 figure

Excursions in Indiana Geology

Indiana Geological Survey Guidebook 12Indiana lies wholly within the Central Lowland Province and thus calls to mind widespread, thin, nearly flat-lying Paleozoic rocks, major unconformities, and extensive plains. These features express epeirogenic submergences of the central part of the continent, long periods of general stability, and, nevertheless, repeatedly interrupted episodes of sedimentation and landform sculpture. Outstanding among these episodes was continental glaciation that carried to the Ohio River. Receiving ice from two principal directions the State's surface nearly everywhere attests to its latest experience, most obviously in the form of a great till plain that is interrupted in its gross appearance by end moraines, valley trains, and ice-contact deposits. Structurally, the State lies athwart a broad crestal area, the Cincinnati Arch, which separates the Michigan Basin on the north from the Illinois Basin on the southwest. Some structural instability, manifest as long ago as Precambrian time, is evident in such sedimentational or second-rank structural features as lithofacies, Silurian-Devonian and Mississippian-Pennsylvanian unconformities that change both locally and regionally in magnitude, and faulting. The more recent erosional record reflects structural history as well, and Paleozoic rocks from middle Ordovician to middle Pennsylvanian in age crop out at the bedrock surface according to their order of superposition. The Paleozoic units west and south of the Cincinnati Arch have special interest on these excursions. Their truncated edges, having differing resistances, are expressed alternately by open vales of gentle relief and uplands consisting of partly dissected westward-facing dip slopes and rugged forested scarps. Within easy range of Bloomington we can demonstrate much of the variety of geologic form characteristic of the State. Crossing the regional strike and the boundary between driftless and glaciated areas, the first day's excursion (inside front cover) is generally eastward to traverse bedrock of Mississippian to Silurian age and drifts assigned to the Kansan, Illinoian, and Wisconsin Stages. It emphasizes the State's most widely known natural product, the Indiana Limestone, and relationships of physiography to bedrock and drift. The second day's excursion (inside back cover) is northwestward from Bloomington and crosses younger bedrock (to middle Pennsylvanian in age). It emphasizes the Mississippian-Pennsylvanian unconformity, stratigraphic relationships of drifts, and some of the newest methods of coal mining and land reclamation.Indiana Geological Survey Indiana Department of Natural Resources American Association of State Geologist

Excursions in Indiana Geology

Our purpose on these excursions arranged for the 58th meeting of the Association of American State Ge ologists is to bring about an awareness of Indiana geology and its attraction. Although our State lacks a Grand Canyon and production of glamour metals, features which in themselves would assure success of a field trip, it nevertheless offers many geologic challenges--challenges that we shall in part take up during these two days

Loop structure of the lowest Bloch band for a Bose-Einstein condensate

We investigate analytically and numerically Bloch waves for a Bose--Einstein condensate in a sinusoidal external potential. At low densities the dependence of the energy on the quasimomentum is similar to that for a single particle, but at densities greater than a critical one the lowest band becomes triple-valued near the boundary of the first Brillouin zone and develops the structure characteristic of the swallow-tail catastrophe. We comment on the experimental consequences of this behavior.Comment: 4 pages, 7 figure