نتایج جستجو برای: electron absorption

تعداد نتایج: 429342  

2004
Joseph Neev Christopher B. Schaffer Fang Shan Joshua D. Carter Vicky Ng Ting Guo

A laser driven electron x-ray source (LEXS) emitting tungsten Lα lines has been built based on a high repetition rate, terawatt laser system. The Lα characteristic lines overlap with the absorption edge of Ni near 8333 eV. Using this x-ray source, the x-ray absorption spectra near the absorption edge of different Ni compounds have been measured. We term this new method “ultrafast selected energ...

1996
P. N. Collis J. K. Hargreaves G. P. White

An isolated region of energetic electron precipitation observed near local noon in the auroral zone has been investigated using imaging riometer (IRIS) and incoherent-scatter radar (EISCAT) techniques. IRIS revealed that the absorption event was essentially co-rotating with the Earth for about 2 h. The spatial and temporal variations in D-region electron density seen by EISCAT were able to be i...

Journal: :The Journal of Biophysical and Biochemical Cytology 1955
Cecil E. Hall

Methods are described for determining the relative mass of particles in electron microscope specimens through the measurement of photographic densities in recorded images. These methods were applied to a quantitative study of the amounts of electron stains that could be associated with the particles of tomato bushy stunt virus (BSV) and tobacco mosaic virus (TMV). In the pH range above 2 where ...

2002
Amlan Majumdar K. K. Choi L. P. Rokhinson D. C. Tsui

Two-color quantum-well infrared photodetectors ~QWIPs! that are based on electron transfer between coupled QWs suffer from the presence of the shorter wavelength peak at all bias voltages. We investigate this problem in such detectors with 50 or 200 Å AlGaAs barriers between the QW pair. We deduce the absorption coefficient a and photoconductive gain g of the detectors with 50 Å barriers using ...

In the present work, first an analytic relation for position-dependent effective mass in a quantum rod is obtained. Then, the effect of position-dependent effective mass on the intersubband optical absorption coeffcient and the refractive index change in the quantum rod is examined. Our numerical calculations are performed using both a constant effective mass and the position-dependent effect...

Journal: :Dalton transactions 2012
Junkuo Gao Xinfeng Liu Yi Liu Lingling Yu Yuhua Feng Hongyu Chen Yongxin Li Ganguly Rakesh Cheng Hon Alfred Huan Tze Chien Sum Yang Zhao Qichun Zhang

A novel pyrene covalently-attached polyoxometalate (POM) hybrid has been synthesized and fully characterized. The attractive electronic and photophysical properties of pyrene derivatives make the hybrid promising for studying and understanding electron transfer mechanisms in organic-functionalized POMs. The hybrid has an electronic absorption at 450 nm, indicating that there is a strong electro...

Journal: :International Journal for Radiation Physics and Chemistry 1975

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