Angebote zu "Spectra" (52 Treffer)

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grundstoff Loves - Jerseyshirt aus Bio-Baumwoll...
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9,95 € *
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Hochwertiges Frauen T-Shirt aus reiner Biobaumwolle. Das T-Shirt ist leicht tailliert geschnitten und hat einen weiten Rundhalsausschnitt. Der Stoff ist angenehm weich und leicht, dadurch ist das T-Shirt sehr bequem zu tragen. Die Herstellung erfolgt unter fairen und umweltfreundlichen Bedingungen. Die verwendete Biobaumwolle ist G.O.T.S zertifiziert und erfüllt somit strenge Auflagen in Bezug auf den biologischen Anbau der Baumwolle und die schadstoffarme Herstellung des fertigen T-Shirts. Material: 100% Biobaumwolle Farbe: gelb Der Artikel wird unter dem Namen grundstoff angeboten und weist eine dezente, von außen nicht sichtbare Veredelung auf. Hergestellt wird das Kleidungsstück von Stanley & Stella, einem Mitglied der Fair Wear Foundation (FWF).

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Stand: 06.06.2020
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The Use of ERS SAR for Measurement of the Direc...
59,00 € *
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The study presented in this work examines the use of Synthetic Aperture Radar (SAR) on-board the first European Remote Sensing Satellite (ERS-1) for the measurement of wind waves and discusses its applications such as wave data assimilation and inverse modelling. Over four years of directional measurements acquired by a heave-pitch-roll buoy moored in tropical deep waters around 150 km offshore are employed to investigate the mechanisms of SAR wave imaging and the retrievals of wave spectra from SAR images. For the first time the most widely implemented Max-Planck Institut (MPI) SAR Wave Mode retrieval scheme was assessed through detailed statistical intercomparisons and selected qualitative validations against directional buoy data and against the third generation wave model WAM data, which was used as first guess to the inversion. The performance of the WAM model, the ECMWF Atmospheric Model and of the Maximum Entropy Method for the retrieval of the buoy directional spectrum are also discussed through several cross-validation exercises.

Anbieter: Dodax
Stand: 06.06.2020
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Synthesis and Application
45,90 € *
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A green chemistry approach for organic synthesis is described here, which involves microwave exposure of reactants in presence or absence of solvents. A novel and simple method has been developed for the synthesis of triazole derivatives under microwave irradiation. A new series of Nano complexes of 2-(1,2,4-triazol-3-ylimino)methyl)-6-methoxyphenol under microwave irradiation. The microwave methodology is rapid and gives a better yield (80-98%). The prepared Schiff base was used for further complex formation reaction with different metal ions using Mn(II), Co(II), Ni(II) and Cu(II) complexes by with a molar ratio of ligand: metal as 1:1. The stereochemistry and the mode of bonding of the complexes were achieved based on elemental analysis, FTIR, UV-Vis, 1HNMR, 13CNMR and Mass Spectroscopy as well as Thermo-Gravimetric Analysis (TGA). Structures proposed for geometry of the chelates based on their electronic spectra and magnetic susceptibility. The solid complexes have been synthesized and studied by TGA analysis. The thermal dehydration and decomposition of the complex was studied kinetically using the integral method applying the Coats-Redfern and Horowitz Metzger equation.

Anbieter: Dodax
Stand: 06.06.2020
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Similarity-Based Clustering
58,84 € *
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Similarity-based learning methods have a great potential as an intuitive and ?exible toolbox for mining, visualization,and inspection of largedata sets. They combine simple and human-understandable principles, such as distance-based classi?cation, prototypes, or Hebbian learning, with a large variety of di?erent, problem-adapted design choices, such as a data-optimum topology, similarity measure, or learning mode. In medicine, biology, and medical bioinformatics, more and more data arise from clinical measurements such as EEG or fMRI studies for monitoring brain activity, mass spectrometry data for the detection of proteins, peptides and composites, or microarray pro?les for the analysis of gene expressions. Typically, data are high-dimensional, noisy, and very hard to inspect using classic (e. g. , symbolic or linear) methods. At the same time, new technologies ranging from the possibility of a very high resolution of spectra to high-throughput screening for microarray data are rapidly developing and carry thepromiseofane?cient,cheap,andautomaticgatheringoftonsofhigh-quality data with large information potential. Thus, there is a need for appropriate - chine learning methods which help to automatically extract and interpret the relevant parts of this information and which, eventually, help to enable und- standingofbiologicalsystems,reliablediagnosisoffaults,andtherapyofdiseases such as cancer based on this information. Moreover, these application scenarios pose fundamental and qualitatively new challenges to the learning systems - cause of the speci?cs of the data and learning tasks. Since these characteristics are particularly pronounced within the medical domain, but not limited to it and of principled interest, this research topic opens the way toward important new directions of algorithmic design and accompanying theory.

Anbieter: Dodax
Stand: 06.06.2020
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New methods and applications in time-resolved X...
49,80 € *
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Time-resolved investigations of condensed matter on an atomic scale level are nowadays indispensable to gain insights in the complex mechanisms of dynamic processes in physics and chemistry. Most of these processes take place at the surface of a metal, such as for example layer growth and corrosion phenomena or all catalytic applications. X-ray absorption spectroscopy is one of the most important investigation tools in this context. It allows resolving the local structure around a selected kind of element in the probed sample within the range of a few Angstroms by using the intense X-ray beams generated at modern synchrotron radiation sources. It is thus perfectly adapted to investigate systems with only a short range order as for example very thin layers or nanoparticles which are especially important for catalytic applications. Prerequisite for X-ray absorption spectroscopy are monochromators with perfect crystals that reflect only a certain energy determined by the incident angle. Time-resolutions of down to a few milliseconds for one spectrum are achievable with quick-scanning X-ray absorption spectroscopy (QEXAFS) using mechanics to rapidly oscillate the monochromator crystals.New technical approaches for the QEXAFS method are presented in this work as for example an angular encoder system to accurately measure the monochromator crystal angle and thus to obtain most accurate energy values for the measured spectra. The design of flexible driving mechanics is introduced and tested. The new mechanics allow arbitrarily adjusting the energy range of the spectra within few seconds leading to a more efficient application of QEXAFS and also new possible experiments. Moreover, a new fast and reliable data acquisition system is presented as well as new user-friendly data analysis software named T-REX to handle the thousands of spectra that are typically collected during each measurement.Several applications in the field of catalysis are presented where new insights in dynamic processes could be obtained using quick-scanning X-ray absorption spectroscopy. The Pd-catalyzed Heck reaction was studied as well as stable oscillations during the catalytic partial oxidation of methane on Pd/Al2O3 catalysts, the oxidation and reduction behaviour of Cu/Al2O3 catalysts at various temperatures and structural oscillations during the extinction of CO oxidation on a Pt/Al2O3 catalyst. Thereby, new data analysis approaches were introduced, as for example a median filter to analyze distorted data resulting from unstable sample conditions and modulation spectroscopy to improve signal-to-noise ratios for processes that can be reproducibly excited by tuning the experimental parameters. As an example for chemical decomposition processes it is reported on QEXAFS studies of the dehydration and decomposition of cobalt oxalates in reducing, oxidizing and inert atmosphere. Finally, data measured in-situ in reflection mode with sub-second timeresolution during the deposition of copper on glass via DC magnetron sputtering are shown yielding new insights in the initial stages of the layer growth processes under realistic deposition conditions. Subsequent oxidation of the fresh Cu layers at various substrate temperatures was also investigated and the obtained results demonstrate the high potential of using QEXAFS to gain new insights into fundamental processes in surface science.

Anbieter: Dodax
Stand: 06.06.2020
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Theory of Nonlinear Propagation of High Harmoni...
139,09 € *
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Theory of Nonlinear Propagation of High Harmonics Generated in a Gaseous Medium establishes the theoretical tools to study High-Order Harmonic Generation (HHG) by intense ultrafast infrared lasers in atoms and molecules. The macroscopic propagation of both laser and high-harmonic fields is taken into account by solving Maxwell's wave equations, while the single-atom or single-molecule response is treated with a quantitative rescattering theory by solving the time-dependent Schrödinger equation.This book demonstrates for the first time that observed experimental HHG spectra of atoms and molecules can be accurately reproduced theoretically when precise experimental conditions are known. The macroscopic HHG can be expressed as a product of a macroscopic wave packet and a photorecombination cross section, where the former depends on laser and experimental conditions while the latter is the property of target atoms or molecules. The factorization makes it possible to retrieve microscopically atomic or molecular structure information from the measured macroscopic HHG spectra.This book also investigates other important issues about HHG, such as contributions from multiple molecular orbitals, the minimum in the HHG spectrum, the spatial mode of laser beams, and the generation of an isolated attosecond pulse. Additionally, this book presents the photoelectron angular distribution of aligned molecules ionized by the HHG light.

Anbieter: Dodax
Stand: 06.06.2020
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High Resolution Infrared Spectroscopy in Astronomy
74,85 € *
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Two specialized new instruments for ESO's VLT, VISIR and CRIRES, spawned the idea for this workshop. CRIRES is a dedicated very high resolution infrared spectrograph, VISIR features a high resolution spectroscopic mode. Together, the instruments combine the sensitivity of an 8m-telescope with the now well-established reliability of VLT-facility instruments. High resolution here means that lines in cool stellar atmospheres and H II -regions can be resolved. The astrophysical topics discussed in this rather specialized workshop range from the inner solar system to active galactic nuclei. There are many possibilities for new discoveries with these instruments, but the unique capability, which becomes available through high-resolution infrared spectroscopy, is the observation of molecular rotational-vibrational transitions in many astrophysical environments. Particularly interesting and surprising in this context, many papers on modeling and laboratory spectroscopy at the workshop appear to indicate that astronomical observations are lagging a bit behind in this field. The papers are an interesting mix of reports from existing high resolution facilities, reports on modeling efforts of synthetic spectra and reports on laboratory spectra. In this sense, a fruitful exchange between molecular physics and astronomy was again accomplished and is documented in this volume.

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Stand: 06.06.2020
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Fabrication and Characterization of Low Cost So...
32,90 € *
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The low cost and low temperature electrochemical deposition technique was employed to grow Cu2O thin films and ZnO:Al thin films were deposited by d.c. magnetron sputtering in order to fabricate solar cells. The potentiostatic and galvanostatic electrodeposition modes were used to deposit the Cu2O thin films. Raman spectra of thin films have shown characteristic frequencies of crystalline Cu2O. The contact between Cu2O and Au is found to be an Ohmic contact. The devices grown by a potentiostatic mode have higher efficiency than those grown by a galvanostatic mode. The optimum thickness of Cu2O thin films as an absorber layer in solar cells. was found to be around 3 µm respect to a high efficiency. Flexible and light weight solar cell was fabricated on plastic substrate.

Anbieter: Dodax
Stand: 06.06.2020
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Fabrication Tapered Nano Fiber Optics
69,90 € *
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Nanofiber is characterized by thin, long, and very soft silica. Taper fibers are made using an easy and low cost chemical method. Etching is conducted with a HF solution to remove cladding and then a low molarity. HF solution to reduce the fiber core diameter. One approach to on-line monitoring of the etching process uses spectrophotometer with a white light source. This method aims to determine the diameter of the reduced core and show the evolution of the two different processes from the nanofiber regime to the fixed regime in which the mode was remote from the surrounding evanescent field, intensity can propagate outside the segment fiber when the core diameter is less than 170 nm. In this work, a simple, intensity-modulated, fiber optic sugar sensor determines the change in the refractive index and concentration of the liquid. Afterwards, an experiment is conducted using two methods to measure the concentration of the liquid, the first utilizes cell cavity and the other, thin optical fiber sensors and spectra photonics.

Anbieter: Dodax
Stand: 06.06.2020
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Raman spectroscopy in organic materials: part I
35,90 € *
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A Raman study relating anharmonicity and thermal decomposition for the first time. In this work high-temperature Raman spectra are used to compare temperature dependence of the lattice mode wavenumber of L-alanine, L-threonine and taurine crystals. Short and strong hydrogen bonds in L-alanine crystal were associated with anharmonic effects in lattice modes leading to low thermal stability compared to taurine crystals. Connection between thermal decomposition process and anharmonic effects is furnished for the rst time.

Anbieter: Dodax
Stand: 06.06.2020
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