نتایج جستجو برای: ray absorption
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مقدمه و اهمیت موضوع: بیوسنتز نانو ذرات نقره با استفاده از آنزیم نیترات ردوکتاز به همراه nadph-? و... در شرایط آزمایشگاهی انجام گرفت. در حضور آنزیم نیترات ردوکتاز یون های نقره احیا گشت و منجر به تشکیل نانو ذرات نقره با اندازه ایی در حدود 50 نانومتر شد. خصوصیات نانوذرات سنتز شده به وسیله زتاسایزر (dls)، پراش پرتو ایکس (x-ray)، میکروسکوپ الکترونی عبوری(tem)، میکروسکوپ الکترونی عبوری(sem) و جذب نور...
a new approach for the synthesis of prussian blue nanoparticles using the cationic surfactant cetyl pyridinium chloride (cpc) as capping agent has been developed in the present work. powder x-ray diffraction, transmission electron microscopy, uv–vis absorption spectra, and ir spectroscopy were employed to characterize the product. the tem image showed that the prussian blue nanoparticles with d...
In this review, high-resolution X-ray emission and X-ray absorption spectroscopy will be discussed. The focus is on the 3d transition-metal systems. To understand high-resolution X-ray emission and resonant X-ray emission, it is first necessary to spend some time discussing the X-ray absorption process. Section II discusses 1s X-ray absorption, i.e., the K edges, and section III deals with 2p X...
X-ray absorptioń spectroscopy, today widely used as a tool for structural investigations, is described. Theoretically it is shown that above an absorption edge the absorption coefficient is well approximated by a sum of terms, each one describing a particular path followed by the photoelectron outgoing from the atom. Such geometrical feature allows to use X-ray absorption spectroscopy for struc...
1.59.1 PHYSICS OF X-RAY ABSORPTION 1 1.59.1.1 X-ray Absorption Edges 2 1.59.1.2 X-ray Fluorescence 3 1.59.1.3 Measurement of X-ray Absorption Spectra 3 1.59.2 EXTENDED X-RAY ABSORPTION FINE STRUCTURE 6 1.59.2.1 Theoretical Description of EXAFS Spectra 6 1.59.2.1.1 Single scattering 6 1.59.2.1.2 Multiple scattering 8 1.59.2.1.3 Other corrections to the EXAFS equation 9 1.59.2.2 Programs for Calc...
The changes in the electronic structure of V2O3 across the metal-insulator transition induced by temperature, doping, and pressure are identified using high resolution x-ray absorption spectroscopy at the V pre-K edge. Contrary to what has been taken for granted so far, the metallic phase reached under pressure is shown to differ from the one obtained by changing doping or temperature. Using a ...
We present 4–7 ks Chandra observations of 35 Broad Absorption Line (BAL) quasars from the Large Bright Quasar Survey, the largest sample of sensitive, 0.5–8.0 keV X-ray observations of this class of quasars to date. The limited ranges in both redshift (z = 1.42–2.90) and ultraviolet luminosity (a factor of ≈ 12) of the sample also make it relatively uniform. Of 35 targets, 27 are detected for a...
Recently, convincing evidence was found for extremely large X-ray absorption by column densities > 1023 cm−2 in broad absorption line quasars. One consequence of this is that any soft X-ray emission from these QSOs would be the scattered light or leaked light from partially covering absorbing material. A detection of the unabsorbed soft X-ray and absorbed hard X-ray component will allow to dete...
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