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

Report on the Stony Corals from the Maldive Archipelago

The Maldive Archipelago, situated at the southwest of India, consists of 22 atolls, extending over a length of nearly 470km in a north-south direction. The northern limit is Ihavandiffulu Atoll (7"'05'N, 72' 55'E), while Addu, one of the scientifically well known atolls, is located at the southern tip (0' 40'5, 73'1 O'E). The largest among the Maldivian atolls is located in the northern half of the chain and is known by twO names, a nonhern smaller part called Tiladummati, and the southern part Miladummadulu. At the middle pan of the Archipelago the atolls are arranged in two almost parallel rows, incorporating a great number of Faros with their small lagoon-like water bodies, termed Velu. The type locality of Atolls and Faros are the Maldives, the names originating from the Maldivian language. Nearly 2000 small islands enter into the geography of the Maldives, of which circa 200 are inhabited with a population of nearly 120000

Report on the Stony Corals from the Red Sea

The first to mention corals of the Red Sea was Thomas SHAW, who travelled through Tunisis , Algeria, Egypt, Syria and the Sinai Peninsula, and who in his "Travels or observations re lati ng to several parts of Barbary and the Levant" described 24 corals of Et Tur (1738, German edition 1765). From these one can recognize P1atygyra, Favia, Goniastrea, Acropora, Stylophora and Tubipora, but his Latin descriptions are not sufficient for an identification at a species level

REACTIVITY OF CHLOROPHYLL a/b-PROTEINS AND MICELLAR TRITON X-100 COMPLEXES OF CHLOROPHYLLS a OR b WITH BOROHYDRIDE

The reaction of several plant chlorophyll-protein complexes with NaBH4 has been studied by absorption spectroscopy. In all the complexes studied, chlorophyll b is more reactive than Chi a, due to preferential reaction of its formyl substituent at C-7. The complexes also show large variations in reactivity towards NaBH4 and the order of reactivity is: LHCI > PSII complex > LHCII > PSI > P700 (investigated as a component of PSI). Differential pools of the same type of chlorophyll have been observed in several complexes. Parallel work was undertaken on the reactivity of micellar complexes of chlorophyll a and of chlorophyll b with NaBH4 to study the effect of aggregation state on this reactivity. In these complexes, both chlorophyll a and b show large variations in reactivity in the order monomer > oligomer > polymer with chlorophyll b generally being more reactive than chlorophyll a. It is concluded that aggregation decreases the reactivity of chlorophylls towards NaBH4 in vitro, and may similarly decrease reactivity in naturally-occurring chlorophyll-protein complexes

Control of the appleseed moth Grapholita lobarzewskii Ragonot in organic fruit growing

Several products were tested for their efficacy in control of the apple seed moth (Grapholita lobarzewskii Ragonot). None of them had a good efficacy. With several treatments with Bacillus thuringiensis an efficacy about 50 % could be achieved. An early treatment before egg-laying seem to improve the results. Quassia extract (9 g Quassin/ha/m tree height) gave efficacy about 50-60 % even if treated only once. NeemAzal gave only moderate efficacy (about 40-50 %). Mating disruption method was effective if the populations were not too high when the treatements were started. With high populations there was no sufficient control in the first year of application

Zur Regulierung des Kleinen Fruchtwicklers Grapholita lobarzewskii Ragonot

Several products were tested for their efficacy in control of the apple seed moth (Grapholita lobarzewskii Ragonot). None of them had a good efficacy. With several treatments with Bacillus thuringiensis an efficacy about 50 % could be achieved. An early treatment before egg-laying seem to improve the results. Quassia extract (9 g Quassin/ha/m tree height) gave efficacy about 50-60 % even if treated only once. NeemAzal gave only moderate efficacy (about 40-50 %). Mating disruption method was effective if the populations were not too high when the treatements were started. With high populations there was no sufficient control in the first year of application

A Comparison of Phycocyanins from Three Different Species of Cyanobacteria Employing Resonance-Enhanced Coherent Anti-Stokes Raman Spectroscopy

Resonance-enhanced coherent anti-Stokes Raman spectra are recorded for monomers and trimers of phycocyanin from three different cyanobacteria: Westiellopsis prolifica, Mastigocladus laminosus and Spirulina platensis. It is shown that upon aggregation from monomer to trimer the electronic structures of both the α84 and β84 chromophores are changed. The spectra of the trimers originating from S. platensis and M. laminosus are very similar to each other, but distinctly different from the spectrum of W. prolifica

Photophysics of phycoerythrocyanins from the cyanobacterium Westiellopsis prolifica studied by time-resolved fluorescence and coherent anti-Stokes Raman scattering spectroscopy

Three building blocks of the antenna complexes of the cyanobacterium Westiellopsis prolifica were studied: PEC(X), which is similar to the α-subunit of phycoerythrocyanin (PEC), trimers of PEC and monomers derived from these by deaggregation with KSCN. The fit of the fluorescence decay curve of PEC(X) requires at least four exponentials, although it supposedly contains only one chromophore. The coherent anti-Stokes Raman scattering (CARS) spectra indicate that the heterogeneity observed is due to geometrical isomers, which are in part generated by photoinduced processes. A similar heterogeneity in chromophore structure and properties is also found in the monomers, where four exponentials are needed to fit the fluorescence decay curve. As in trimers, there is a long-lived, low-amplitude component, which can be assigned to impurities and/or oxidation products. The energy transfer time between the two phyocyanobilin chromophores in the β-subunit is about 500 ps; the lifetime of the fluorescing β-chromophore is 1.5 ns. The phycoviolobilin chromophore in the α-subunit adopts different geometries characterized by fluorescence lifetimes of about 240 and 800 ps. No evidence was found for energy transfer between the α-chromophore and the β-chromophores. This energy transfer occurs in trimers on a time scale of less than 20 ps; the energy transfer time between the two different types of β-chromophore is about 250 ps and the lifetime of the terminal emitter is about 1.5 ns. The excited state kinetics are therefore similar to those of PEC trimers from Mastigocladus laminosus, as are the CARS spectra, indicating a similar chromophore—protein arrangement. In comparison with phycocyanin, the ordering of the excited states of chromophores β84 and β155 may be changed. Although PEC trimers of Westiellopsis prolifica show almost as good a photostability as trimers of Mastigocladus laminosus, monomers are so photolabile that no CARS spectra could be recorded

Single-channel transmission in gold one-atom contacts and chains

We induce superconductivity by proximity effect in thin layers of gold and study the number of conduction channels which contribute to the current in one-atom contacts and atomic wires. The atomic contacts and wires are fabricated with a Scanning Tunneling Microscope. The set of transmission probabilities of the conduction channels is obtained from the analysis of the $I(V)$ characteristic curve which is highly non-linear due to multiple Andreev reflections. In agreement with theoretical calculations we find that there is only one channel which is almost completely open.Comment: 4 pages, 2 figures. To be published in Phys. Rev. B, Rapid Communications (2003

Sub-femtosecond absolute timing precision with a 10 GHz hybrid photonic-microwave oscillator

We present an optical-electronic approach to generating microwave signals with high spectral purity. By circumventing shot noise and operating near fundamental thermal limits, we demonstrate 10 GHz signals with an absolute timing jitter for a single hybrid oscillator of 420 attoseconds (1Hz - 5 GHz)