absorption spectroscopy Articles
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Spectroscopic analysis of boron porphyrin complexes
Spectroscopic analyses of diboron porphyrin complexes have been performed using femtosecond transient absorption spectroscopy, fluorescence spectroscopy measurements, IR and Raman spectroscopy as well as DFT and TDDFT calculations. Transient absorption spectroscopy was used to study the dynamics of the transient species by exciting the molecule with a ~100 fs pulse of light at the wavelength ...
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Synchrotron radiation, soft-X-ray spectroscopy and nanomaterials
Both synchrotron radiation based soft-X-ray absorption spectroscopy (XAS) and resonant soft-X-ray emission spectroscopy (XES) on a variety of nano-structured systems has yielded characteristic fingerprints. With high-resolution monochromatized synchrotron radiation excitation, resonant inelastic X-ray scattering (RIXS) has emerged as a new source of information about electronic structure and ...
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Covalently-bound organic monolayers for biosensor applications
In this paper, we present a detailed investigation on monolayer formation with thicknesses amounting 1 nm to 3 nm on silicon and silicon nitride surfaces. Thermal and photochemical methods are successfully used to form such stable and densely backed monolayers. Further, functionalisation of these surfaces with activated esters, amine groups are also presented. Static water contact angle ...
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What is Transient Absorption Spectroscopy?
Transient absorption (TA) spectroscopy, also known as flash photolysis, is a pump-probe spectroscopic technique utilised to measure the photogenerated excited state absorption energies and associated lifetimes of molecules, materials, and devices. The pump-probe technique can be described by a sample being photo-excited by a light source (pump pulse), whereby a second light source (probe pulse) ...
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SrTi
1xNixO3nanoparticles: synthesis and characterisationWe present the synthesis of SrTi1xNixO3 (STNO) (x = 0.00, 0.10, 0.20, 0.30, 0.40, 0.50) nanoparticles and investigate their structure, absorption spectra, temperature-dependent Raman spectroscopy, impedance spectroscopy and magnetic property. Nanoparticles of STNO were prepared by sol-gel method. The particle size is smaller than 30 nm and depends on the Ni-substituted content. The experimental ...
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Determination of macro, micro nutrient and trace element concentrations in Indian medicinal plants using instrumental neutron activation analysis and atomic absorption spectroscopy techniques
Specific parts (fruits and seeds) of different medicinal plants often used in Indian Ayurvedic system were analysed for 18 elements (K, Mn, Na, Fe, Zn, Cu, Co, Br, Sm, Cl, La, Al, Cr, Ca Cd, Ni, Pb and Hg) by employing instrumental neutron activation analysis (INAA) and atomic absorption spectroscopy (AAS) techniques. The samples were irradiated with thermal neutrons in a nuclear reactor and the ...
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Indirect Determination of Gold Purity by Measurement of Impurities with Flame Atomic Absorption Spectroscopy
The determination of the purity of scrap and refined gold is a very important procedure for the financial markets, the jewelry business and the electronics industry. Over the years, the classical fire assay technique has been used for gold determination but this is a very labor-intensive procedure, and prone to many operator errors. Hundreds of books have been written with special steps ...
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What is UV-DOAS?
What is UV-DOAS? UVDOAS (Ultraviolet Differential Optical Absorption Spectroscopy) is a monitoring technique which uses the absorbance of UV light to identify and quantify gases within a sample. Gases absorb unique wavelengths of light, creating a unique fingerprint of each compound within the absorbance spectrum; the amplitude of the absorbance wavelength is proportional to the concentration of ...
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Room temperature, water-based, microreactor synthesis of gold and silver nanoparticles
Synthesis of gold and silver nanoparticles at room temperature using a polydimethylsiloxane (PDMS) microreactor has been reported. The reactions have been performed using aqueous metal salt solutions and borohydride reducing agent with tri-sodium citrate as the capping agent. Effect of concentration of reducing agent on the optical properties of the nanoparticles has been investigated. The ...
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Application of surface complexation models to anion adsorption by natural materials
Various chemical models of ion adsorption will be presented and discussed. Chemical models, such as surface complexation models, provide a molecular description of anion adsorption reactions using an equilibrium approach. Two such models, the constant capacitance model and the triple layer model will be described. Characteristics common to all the surface complexation models are equilibrium ...
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Nanoparticles and nanowires: synchrotron spectroscopy studies
This paper reviews the research in nanomaterials conducted in our laboratory in the last decade using conventional and synchrotron radiation techniques. While preparative and conventional characterisation techniques are described, emphasis is placed on the analysis of nanomaterials using synchrotron radiation. Materials of primary interests are metal nanoparticles and semiconductor nanowires and ...
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INAA and AAS study of essential trace elements in ayurvedic Indian medicinal plants
Specific parts (leaves and fruits) of different medicinal plants often used in Indian ayurvedic system were analysed for 18 elements (K, Mn, Na, Fe, Zn, Cu, Co, Br, Sm, Cl, La, Al, Cr, Ca Cd, Ni, Pb and Hg) by employing instrumental neutron activation analysis (INAA) and atomic absorption spectroscopy (AAS) techniques. The samples were irradiated with thermal neutrons in a nuclear reactor and the ...
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Development of novel integrated bio/chemical sensor systems using chalcogenide glass materials
This paper reviews ongoing progress in the design and fabrication of new, on-chip, low loss planar molecular sensors. We report the details of device design, material selection and manufacturing processes used to realise high-index-contrast (HIC), compact micro-disk resonators. These structures have been fabricated in thermally evaporated As- and Ge-based chalcogenide glass films with PDMS ...
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The speciation of silver nanoparticles in antimicrobial fabric before and after exposure to a Hypochlorite/Detergent solution
Because of their antibacterial properties, silver nanoparticles are often used in consumer products. To assess environmental and/or human health risks from these nanoparticles, there is a need to identify the chemical transformations that silver nanoparticles undergo in different environments. Thus an antimicrobial sock material containing Ag nanoparticles was examined by X-ray absorption ...
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On-line measurements of flue gas concentrations of cadmium and lead in a co-combustion in a fluidized bed boiler
ABSTRACT The operation of a new on-line toxic metal analyser was demonstrated in connection to a pilot-scale bubbling fluidised bed boiler during co-combustion tests of biomass and waste fuels. The analyser comprises a novel continuous sampling device combined with DC-plasma excited atomic absorption spectroscopy and Zeeman background correction. A continuous sample gas flow is extracted from a ...
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Learn More About TDLAS Gas Analyzer: Principles, Applications and Features
Tunable Diode Laser Absorption Spectroscopy (TDLAS) is an infrared absorption spectrum analysis technology that uses the principle of “frequency-selective” absorption of molecules to form an absorption spectrum to achieve high-resolution quantitative analysis of molecular concentration. TDLAS is capable of in-situ non-contact measurement and has the characteristics of high precision ...
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Characterisation of the recalcitrant organic compounds in leachates formed during the anaerobic biodegradation of waste
This study investigates the use of UV absorption and fluorescence spectroscopy to assess the early development of recalcitrant organic compounds in leachates formed during the anaerobic biodegradation of municipal solid waste. Biochemical methane potential tests were carried out on fresh waste (FW) and composted waste (CW) over a period of 150 days and leachates produced from the degradation of ...
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Toxicity and biotransformation of ZnO nanoparticles in the desert plants Prosopis juliflora-velutina, Salsola tragus and Parkinsonia florida
Although arid and semiarid regions account for about 40% of world land, no nanotoxicity studies on desert plants have been reported. In this investigation, Parkinsonia florida (blue palo verde), Prosopis juliflora-velutina (velvet mesquite) and Salsola tragus (tumbleweed) were selected to determine the phytotoxicity of ZnO nanoparticles (NPs) at germination stage. Seeds were treated with ZnO NP ...
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Silver nanoparticles embedded three dimensional silicate sol–gel matrix modified electrode for nitrite sensor application
A simple amperometric sensor was fabricated by using silver nanoparticles (Agnps) embedded three dimensional silicate sol–gel (SG) matrix (SG–Agnps). The silver nanoparticles stabilised by SH functionalised 3–D silicate sol–gel network was coated on the glassy carbon electrode and used for the determination of nitrite ion in 0.1 M PBS (pH 7.2). The prepared silver nanoparticles–silicate sol–gel ...
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Measurement of ammonia emissions using various techniques in a comparative tunnel study
A field-based intercomparison study for ammonia measurements was conducted using seven analytical methods. It included sulphuric acid impinger, citric acid denuder, differential optical absorption spectroscopy (DOAS), Fourier transform infrared spectroscopy (FTIR), photoacoustic spectroscopy (PAS), and continuous aqueous extraction followed by measurement of conductivity (Airrmonia). Measurements ...
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