Imaging of the expansion of femtosecond-laser-produced silicon plasma atoms by off-resonant planar laser-induced fluorescence

Planar laser-induced fluorescence measurements were used to investigate the expansion dynamics of a femtosecond laser-induced plasma. Temporally and spatially resolved measurements were performed to monitor the atoms that were ablated from a silicon target. A dye laser (lambda = 288.16 nm) was used to excite fluorescence signals. The radiation of an off-resonant transition (Si 390.55 nm) was observed at different distances from the target surface. This allowed easy detection of the ablated Si atoms without problems caused by scattered laser light. Abel inversion was applied to obtain the radial distribution of the Si atoms. The atom distribution in the plasma shows some peculiarities, depending on the crater depth.     

Detection of viable Cryptosporidium parvum using DNA-modified liposomes in a microfluidic chip

This paper describes a microfluidic chip that enables the detection of viable Cryptosporidium parvum by detecting RNA amplified by nucleic-acid-sequence-based amplification (NASBA). The mRNA serving as the template for NASBA is produced by viable C. parvum as a response to heat shock. The chip utilizes sandwich hybridization by hybridizing the NASBA-generated amplicon between capture probes and reporter probes in a microfluidic channel. The reporter probes are tagged with carboxyfluorescein-filled liposomes. These liposomes, which generate fluorescence intensities not obtainable from single fluorophores, allow the detection of very low concentrations of targets. The limit of detection of the chip is 5 fmol of amplicon in 12.5 microL of sample solution. Samples of C. parvum that underwent heat shock, extraction, and amplification by NASBA were successfully detected and clearly distinguishable from controls. This was accomplished without having to separate the amplified RNA from the NASBA mixture. The microfluidic chip can easily be modified to detect other pathogens. We envision its use in mu-total analysis systems (mu-TAS) and in DNA-array chips utilized for environmental monitoring of pathogens.     

Examining the consistency of products derived from various ocean color sensors in open ocean (Case 1) waters in the perspective of a multi-sensor approach

During its lifetime, a space-borne ocean color sensor provides world-wide information about important biogeochemical properties of the upper ocean every 2 to 4 days in cloudless regions. Merging simultaneous or complementary data from such sensors to obtain better spatial and temporal coverage is a recurring objective, but it can only be reached if the consistency of the sensor-specific products, as delivered by the various Space Agencies, has first been carefully examined. The goal of the present study is to provide a procedure for establishing a coherency of open ocean (Case-1 waters) data products, for which the various data processing methods are sufficiently similar. The development of the procedure includes a detailed comparison of the marine algorithms used (after atmospheric corrections) by space agencies for the production of standard products, such as the chlorophyll concentration, [Chl], and the diffuse attenuation coefficient, K_d. The MODIS-Aqua, SeaWiFS and MERIS [Chl] products agree over a wide range, between ∼ 0.1 and 3 mg m^− 3, whereas increasing divergences occur for oligotrophic waters ([Chl] (from 0.02 to 0.09 mg m^− 3). For the K_d(490) coefficient, different algorithms are in use, with differing results. Based on a semi-analytical reflectance model and hyperspectral approach, the present work proposes a harmonization of the algorithms allowing the products of the various sensors to be comparable, and ultimately, meaningfully merged (the merging procedures themselves are not examined). Additional potential products, obtained by using [Chl] as an intermediate tool, are also examined and proposed. These products include the thickness of the layer heated by the sun, the depth of the euphotic zone, and the Secchi disk depth. The physical limitations in the predictive skill of such downward extrapolations, made from information concerning only the upper layer, are stressed.     

Event-related potential indicators of text integration across sentence boundaries.

An event-related potentials (ERPs) study examined word-to-text integration processes across sentence boundaries. In a two-sentence passage, the accessibility of a referent for the first content word of the second sentence (the target word) was varied by the wording of the first sentence in one of the following ways: lexically (explicitly using a form of the target word); conceptually (using a paraphrase of the target word), and situationally (encouraging an inference concerning the referent of the target word). A baseline condition had no coreference between the two sentences. ERP results on the target word indicated multiple effects related to word identification and word-to-referent mapping processes. Both the explicit and paraphrase conditions, but not the inference condition, showed a reduced N400 relative to the baseline condition, consistent with immediate integration by lexico-semantic processes. A 300-ms effect (P300) was found in the paraphrase condition. The results were consistent with an immediate integration hypothesis and furthermore differentiated a lexical (N200), a conceptual (P300), and a situational (N400) component for this integration. The conceptual basis appears not to extend to predictive inferences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mechanism Oriented Steel Development

The paper discusses how physically based material models can contribute to the development and optimization of new materials. In combination with using enhanced simulation techniques such as density functional theory a true multi scale material development can be established.     

Developing Biotechnology Clusters in Non-high Technology Regions—The Case of Austria

This paper explores the role of distant knowledge links and policy actions for the development of biotechnology clusters. It seeks to challenge the prevailing view that the birth and early development of high technology industries are always spontaneous phenomena which are mainly based on local knowledge. Departing from the theoretical concept of regional innovation systems (RIS), a distinction between “RIS with strong potentials for high technology industries” and “RIS with weak potentials for high technology industries” will be drawn. It will be argued that in the latter case the development of biotechnology clusters is more dependent on distant knowledge sources and proactive policy efforts to create a favourable environment for high technology activities. Furthermore, it will be shown that a far-reaching transformation of the regional innovation system is crucial for catching-up processes of regions which are latecomers in high technology sectors such as biotechnology.     

Quasicrystal–crystal structural transformation in Al–5 wt.% Mn alloy

The atomic structure of Al–5 wt.%Mn (Al–5Mn) alloy, prepared by rapid solidification, and pre-annealed at 623 and 773 K for 5 and 1 h, respectively, were characterized by X-ray powder diffraction (XRD) and extended X-ray absorption fine structure (XAFS) techniques. The sample in as-quenched stage was found crystalline, consisting of metastable α-Al (Al–Mn solid solution) and icosahedral quasicrystalline I-Al₆Mn phases. Five hours annealing at 623 K proved thermal stability of both the phases. Pre-annealing at 773 K/1 h on the other hand leads to α-Al phase decomposition and structural transformation of metastable I-Al₆Mn to stable orthorhombic Al₆Mn phase. The EXAFS results indicate that Mn atoms are located preferably on the outer shell of icosahedrons. During the I-Al₆Mn→o-Al₆Mn transformation the total Al atoms coordinating one Mn were found to be constant (∼10). Based on the results, only distance/symmetry changes in atomic arrangement around Mn atoms were suggested.     

Quantized UWB Transmitted Reference Systems

Digital implementation of ultra-wideband receivers requires analog-to-digital conversion (ADC) at an extremely high speed, thereby limiting the available bit resolution. Herein, the effect of low bit resolution quantization on the performance of UWB transmitted reference receivers is investigated. It is verified that the gain of the automatic-gain-control (AGC) has a significant effect on the achievable performance. Because of the considerable performance loss of conventional transmitted reference receivers in the presence of a low resolution ADC a new family of receiver structures optimized and tailored to quantized observations is presented. In particular, the generalized- likelihood ratio test (GLRT) based on the quantized samples is derived and shown to provide modest performance gains relative to the infinite resolution GLRT rule employed on the quantized received signal suggesting that conventional receiver structures can also be employed in the presence of a low resolution ADC. Results reveal that four bits of resolution in combination with an optimal choice for the AGC gain are sufficient to closely approach the performance of an infinite resolution receiver.     

Microstructural Characterization of Lamellar Features in TiAl by FIB Imaging

A novel experimental procedure is introduced to determine phase fractions and the distribution of individual phases of TiAl‐based two‐phase alloys using the focused ion beam (FIB) technique. Two γ‐titanium aluminide alloys with a fine‐grained duplex and a nearly lamellar microstructure are examined. The special FIB‐based preparation procedure results in high contrast ion beam‐induced images for all investigated alloys and allows to quantify the phase contents easily by automated microstructural analysis. Fine two‐phase structures, e.g. lamellar colonies in γ‐TiAl, can be imaged in high resolution with respect to different phases. To validate the FIB‐derived data, we compare them to results obtained with another method to determine phase fractions, electron back‐scatter diffraction (EBSD). This direct comparison shows that the FIB‐based technique generally provides slightly higher α₂‐fractions, and thus helps to overcome the limited lateral resolution near grain boundaries and interfaces associated with the conventional EBSD approach. Our study demonstrates that the FIB‐based technique is a simple, fast, and more exact way to determine high resolution microstructural characteristics with respect to different phase constitutions in two‐phase TiAl alloys and other such materials with fine, lamellar microstructures.     

Thermisches Betriebsverhalten einer Bandsinteranlage

Es wird ein vereinfachtes mathematisches Modell vorgestellt, mit dessen Hilfe das thermische Betriebsverhalten einer Bandsinteranlage in Abhängigkeit verschiedener Parameter wie Koksgrusgehalt oder Feuchte der Sintermischung beschrieben werden kann. Das Modell enthält als Grundgleichung die instationäre Wärmetransportgleichung, die mit einem modifizierten Newton-Euler-Verfahren gelöst wird. Es ist so konzipiert, daß es in ein umfassendes Energiemodell für ein Hüttenwerk integriert werden kann. Es dient damit im weiteren Sinne als Hilfsmittel für die Energiesteuerung im Hüttenwerk. Durch Simulationsrechnungen wird der Einfluß von Wärm- und Wärmebehandlungshauben über dem Sinterband auf die Leistungsfähigkeit der Sinteranlage aufgezeigt. Je nach Abdeckungsgrad des Sinterbandes durch Wärmhauben und den dort herrschenden Temperaturen kann bis zu 15% Koksgrus eingespart werden.