نتایج جستجو برای: optical spectra

تعداد نتایج: 362167  

2014
Artur Nenov Ivan Rivalta Giulio Cerullo Shaul Mukamel Marco Garavelli

Two-dimensional (2D) optical spectroscopy techniques based on ultrashort laser pulses have been recently extended to the optical domain in the ultraviolet (UV) spectral region. UV-active aromatic side chains can thus be used as local highly specific markers for tracking dynamics and structural rearrangements of proteins. Here we demonstrate that 2D electronic spectra of a model proteic system, ...

Journal: :international journal of nanoscience and nanotechnology 2009
a. pourahmad sh. sohrabnezhad

this work describes the optical and structure properties of nickel sulfide and cobalt sulfide nanoparticles in zsm-5 zeolite. the samples were obtained by sulfidation of the ni2+ and co2+ ion-exchange zsm-5 zeolites in a na2s solution at room temperature. the optical properties of the samples were studied by uv-visible spectroscopy. their crystalline structure and morphology were studied by x-r...

Journal: :The journal of physical chemistry letters 2017
Daniele M Monahan Liang Guo Jia Lin Letian Dou Peidong Yang Graham R Fleming

A hot phonon bottleneck may be responsible for slow hot carrier cooling in methylammonium lead iodide hybrid perovskite, creating the potential for more efficient hot carrier photovoltaics. In room-temperature 2D electronic spectra near the band edge, we observe amplitude oscillations due to a remarkably long lived 0.9 THz coherent phonon population at room temperature. This phonon (or set of p...

اتفاق, ریحانه, متولی زاده, لیلی, قربانی, الهه ,

SnO2 nanotubes have been synthesized via sol-gel template method using alumina membrane. Synthesis parameters, such as sol preparation conditions, the required time of immersion and annealing conditions, were optimized to obtain the SnO2 nanotubes with well defined composition. Transmission electron microscopy (TEM) and X-ray diffraction techniques have been used to investigate the structure an...

I. Skinner, N. Granpayeh, P.L. Chu,

In this paper, a brief summary of different methods of fabrication of optical preform and fiber is reviewed. Several methods of incorporation of erbium ions into optical preforms are studied. Characterization of the fabricated erbium doped fibers including measurements of refractive index profile, absorption, fluorescence and gain spectra and metastable lifetime are described. It is also expres...

mina eslamifar, nastaran mansour,

In this work, thermo-optical properties of gold nanoparticle colloids are studied using continuous wave (CW) laser irradiation at 532 nm. The nanoparticle colloids are fabricated by 18 ns pulsed laser ablation of pure gold plate in the distilled water. The formation of the nanoparticles has been evidenced by optical absorption spectra and transmission electron microscopy. The nonlinear optical ...

Journal: :Publications of the Astronomical Society of the Pacific 1984

حمید هراتی‌زاده, , مرتضی اسمعیلی, , پر اولاف هولتز, ,

Internal polarizations field which take place in quantum structures of group-III nitrides have an important consequence on their optical properties. Optical properties of wurtzite AlGaN/GaN quantum well (QW) structures grown by MBE and MOCVD on c-plane sapphire substrates have been investigated by means of photoluminescence (PL) and time resolved photoluminescence (TRPL) at low-temperature. PL ...

1998
Alexei V. Filippenko

The temporal evolution of the optical spectra of various types of supernovae (SNe) is illustrated, in part to aid observers classifying supernova candidates. Type II SNe are defined by the presence of hydrogen, and they exhibit a very wide variety of photometric and spectroscopic properties. Among hydrogen-deficient SNe (Type I), three subclasses are now known: those whose early-time spectra sh...

Journal: :journal of sciences islamic republic of iran 0

very smooth thin films of iridium have been deposited on super polished fused silica (sio2) substrates using dc magnetron sputtering in argon plasma. the influence of deposition process parameters on film micro roughness has been investigated. in addition, film optical constants have been determined using variable angle spectroscopic ellipsometery, over the spectra range from vacuum ultraviolet...

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