1,354,166 research outputs found
August Christoph von Wackerbarth: Diplomat – Baumeister – Kunstsammler
No full textWer den Namen Wackerbarth hört, denkt in der Regel an Sekt, vielleicht auch an das Schloss, selten jedoch an den Reichsgrafen von Wackerbarth − sein Wirken als Militär, Diplomat, Baumeister und Kunstsammler. Den Höhepunkt seiner militärischen Karriere bildet die Ernennung zum Generalfeldmarschall und sein Wirken als militärischer Chef des Zeithainer Lustlagers. Ab 1685 ist er Generalintendant des Bauwesens in Dresden. Unter Wackerbarth als Auftraggeber und Knöffel als Architekt entstehen mehrere, zum Teil heute noch erhaltene Objekte in und um Dresden. Dazu zählen die drei Gartenanlagen Großsedlitz, Wackerbarths Ruh und Zabeltitz.Normally when people hear the name Wackerbarth, they think of sparkling wine, or perhaps also of the castle in Radebeul. Rarely does anyone think of Count von Wackerbarth in relation to his activities as a soldier, diplomat, architect and art collector. The high point of his military career came with his appointment as Field Marshal General and his role as Chief of the Zeithainer Lustlager military showground. From 1685 onwards he was Director of Construction in Dresden. With Wackerbarth as commissioner and Johann Christoph Knöffel as architect, a number of major construction projects were completed in and around Dresden. Several of these, such as the gardens at Großsedlitz, Wackerbarths Ruh and Zabeltitz, have survived until today
The role of the dielectric environment in surface-enhanced Raman scattering on the detection of a 4-nitrothiophenol monolayer
No full textNanotechnology enables the generation and characterization of novel surface-enhanced Raman scattering (SERS) substrates. In this study, we focus on the impact of the carrier material of the SERS active layer and hence the dielectric environment to the enhancement. Therefore, a self-assembled monolayer of 4-nitrothiophenol is immobilized on silver and gold particles substrates on a quartz carrier. The detection of the monolayer occurs through the quartz carrier and through air. For the former, an increase of the intensity of the SERS bands in the spectrum is observed compared to the latter. The magnitude of the increase is larger for gold than for silver. Calculations according to the theoretical model of the electromagnetic enhancement agree with our experimental data. The presented detection mode will stimulate the fabrication of novel SERS sensors. Copyright (c) 2013 John Wiley & Sons, Ltd.German Federal Ministry of Education and Research [13N11772
Generation of a miniaturized free-flow electrophoresis chip based on a multi-lamination technique—isoelectric focusing of proteins and a single-stranded DNA fragment
No full textFree-flow electrophoresis techniques have been applied for separations in various areas of chemistry and biochemistry. Here we focus on the generation of a free-flow electrophoresis chip and direct monitoring of the separation of different molecules in the separation bed of the miniaturized chip. We demonstrate a fast and efficient way to generate a low-cost micro-free-flow electrophoresis (mu FFE) chip with a filling capacity of 9.5 mu L based on a multi-lamination technique. Separating webs realized by two transfer-adhesive tapes avoid the problem of gas bubbles entering the separation area. The chip is characterized by isoelectric focusing markers (IEF markers). The functionality of the chip is demonstrated by free-flow isoelectric focusing (FFIEF) of the proteins BSA (bovine serum albumin) and avidin and a single-stranded DNA (ssDNA) fragment in the pH range 3 to 10. The separation voltage ranges between 167 V cm(-1) and 422 V cm(-1), depending on the application.German Federal Ministry of Education and Research [01RI0643A
Combined measurement of concentration distribution and velocity field of two components in a micromixing process
No full textA lot of production processes involve mixing steps. The understanding of fluid flows in mixing processes of liquid components is needed in order to develop appropriate mixers for the chemical and pharmaceutical industry. Especially mixing in microfluidic systems is a challenge due to the diffusion-based processes. A multi-lamination micromixer with chessboard outlet geometry is used to induce the mixing process. To get comprehensive information about the mixing process, the velocity profile of the fluid flow and the species concentration distribution during the mixing process should be measured. Thus, we have combined particle image velocimetry (PIV) and Raman scattering. To enable rapid detection, the Raman imaging mode is used to visualise the concentration distribution. By this setup light sheets along and orthogonal to the outlet of the micromixer are recorded and synchronized with PIV measurement. As a model system we have used water and ethanol/methanol, enabling a selective monitoring of the substances by choosing appropriate spectral areas. The PIV is recorded based on Mie scattering and fluorescence using microsphere tracers. In this study, we present a setup for determination of the velocity profile field and the spatial concentration distribution of water and ethanol/methanol in a micromixer
August Christoph von Wackerbarth als Soldat in sächsischen Diensten: Vom Pagen zum Generalfeldmarschall
No full textAugust Christoph von Wackerbarth erwarb seinen Ruf in erster Linie im sächsischen Bauwesen. Doch gleichzeitig trug er den Rock seines Königs als Uniform und war den größten Teil seines Lebens neben den vielen anderen Funktionen Offizier in der kursächsischen Armee. Der Beginn seiner militärischen Laufbahn glich mustergültig der Schablone frühneuzeitlicher Karrieren, doch ab einem bestimmten Zeitpunkt durchbrach Wackerbarth den üblichen Referenzrahmen und stieg bis zum höchsten sächsischen Militär auf. In dem Aufsatz werden die wesentlichen Stationen seines militärischen Werdeganges dargestellt und einzelne Aspekte detaillierter betrachtet.August Christoph von Wackerbarth gained his reputation primarily as a result of his building work in Saxony. However, alongside his many other activities he spent most of his life wearing the King’s uniform as a serving officer in the Saxon army. Initially Wackerbarth’s military career followed a classic trajectory, however at a certain point he broke free of the usual frame of reference and rose to the very top of the Saxon military establishment. The article describes the essential stages of his progression through the ranks of the military and examines certain aspects of his career in greater detail
Highly periodic Au nano-disc arrays for plasmon-resonant SERS structures on fused silica using UV-NIL based double-layer lift-off process
No full textAu nanostructures of different types are widely employed as substrates for surface-enhanced Raman spectroscopy (SERS) due to their strong plasmon-related near-field enhancement in the visible and NIR frequency range as well as their potential for biologically active interfaces. We report on a fabrication route for highly periodic Au nano-discs by combination of laser interference lithography (LIL) with nanoimprint lithography (NIL) using a double-layer lift-off process to produce extremely homogenous periodic arrays over areas of 6 '' wafer scale with sufficiently sharp plasmonic resonance. FDTD simulations were done to yield specifically designed plasmonic activity at a wavelength of 785 nm commonly used in Raman spectrometers. Optical characterisation of the resulting samples was compared to simulation predictions and linked to SERS signal intensity and reproducibility. (C) 2017 Elsevier B.V. All rights reserved
Challenge of false alarms in nitroaromatic explosive detection—a detection device based on surface-enhanced Raman spectroscopy
No full textA challenge in the detection of explosives is the differentiation between explosives and contaminants. Synthetic musk-containing perfumes can cause false alarms, as these perfumes are nitroaromatic compounds, which can be mistaken for trinitro toluene (TNT) by some detectors. We present a detection principle based on surface-enhanced Raman scattering (SERS). A stream of the airborne compounds is focused and resublimated on a cooled nanostructured gold surface. We recorded high-resolution SERS spectra of TNT, musk xylene, and musk ketone. The nitroaromatic compounds can be identified unambiguously by their SERS spectra. Even the dominant bands containing nitro-group scissoring and symmetric stretching modes are significantly shifted by the difference in molecular structure. (C) 2010 Optical Society of Americ
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
In situ Raman imaging combined with computational fluid dynamics for measuring concentration profiles during mixing processes
No full textMicro structured components for process engineering have gained increasing importance in chemical, pharmaceutical and life sciences applications. Understanding of mixing processes in those devices is of fundamental interest for their performance. Raman imaging with light sheets is a powerful tool to visualize concentration profiles. For the first time planar Raman imaging is combined with computational fluid dynamic (CFD) calculations to analyze the concentration of two components at the outlet of a micro mixer. The mixing process was monitored within an attached quartz cuvette. The laser light sheet had a thickness of 0.5 mm and a width of 10 mm matching the inner width of the cuvette. In this investigation ethanol and water were mixed. We present measured concentration maps within 10 mm x 10 mm using single shot laser pulses (6 ns). The lateral resolution is only determined by the pixel size of the CCD camera. Standard deviations and averaged data of the concentration profiles are compared with CFD calculations. The computations were done for a laminar flow at constant temperature under non-steady-state conditions. (C) 2011 Elsevier B.V. All rights reserved
Infrared spectroscopic concentration measurements of carbon dioxide and gaseous water in harsh environments with a fiber optical sensor by using the HITEMP database
No full textThis study presents a method for concentration measurements of carbon dioxide and gaseous water. CO2 and H2O are infrared active substances with strong overlapping absorption bands in the spectral range at about 3700 cm(-1) due to the excitation of molecule vibrations. The analysis is based on the HITEMP database which was used to quantify spectral integrated transmission measurements. A fiber optical spark plug sensor with an absorption path close to the electrodes was used for in-cylinder measurements of carbon dioxide and gaseous water. The sensor system consists of a tungsten halide lamp as a broadband source and two infrared detectors with different optical bandpass filters. The developed calibration procedure was evaluated by using a heatable optical cell. Various gas compositions were analyzed at pressures up to 1800 kPa within a temperature range from 298 to 573 K under well defined conditions. Finally, the calibration procedure was adapted for in situ measurements of CO2 and H2O concentrations in the cylinder of a spark ignited (SI) engine. Concentrations were measured time resolved for motored as well as fired engine conditions. (C) 2013 Elsevier Ltd. All rights reserved.Federal Ministry of Education and Research (BMBF, Germany
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