The evolution of the electronic absorption edge of type I, II and III kerogen is studied by diffuse reflectance UV–Visible absorption spectroscopy. The functional form of the electronic absorption edge for all kerogens measured is in excellent agreement with the ‘‘Urbach tail’’ phenomenology. The Urbach decay width extracted from the exponential fit within the visible range is strongly correlat...

Borosilicate BK7 glasses doped with different amounts of CeO2 (0.5,1,1.5%) were prepared by the convenient melting process in this work. DTA analysis proved that 0.5-1% CeO2 has a network modifier role and then up to 1.5% it shows network former role.For structural studies, FT-IR and Raman spectroscopy were carried out. Fermi energy level, direct/ indirect optical band gap and Urbach energy wer...

Nanocrystalline PbTe films are deposited on different substrates at room temperature through thermal evaporation. The films are stoichiometric single-phase polycrystalline with 200 texture. Electrical properties of the films are analyzed in the framework of a grain boundary channel conduction model. The index of refraction and extinction coefficient of PbTe films are extracted from infrared spe...

Achia Urbach,1,2,4 Ori Bar-Nur,3,4 George Q. Daley,1,2,* and Nissim Benvenisty3,* 1Stem Cell Transplantation Program, Division of Pediatric Hematology/Oncology, Manton Center for Orphan Disease Research, Howard Hughes Medical Institute, Children’s Hospital Boston and Dana Farber Cancer Institute; Division of Hematology, Brigham and Women’s Hospital, Boston, MA 02115, USA 2Department of Biologic...

Optical spectroscopy techniques, including visible and near infrared (IR) Raman and synchrotron IR methods have been applied to study solid nitrogen at megabar pressures. We find that nitrogen becomes totally opaque above 150 GPa, accompanied by the disappearance of Raman and IR vibrational excitations, while new broad IR and Raman bands become visible. Optical absorption measurements reveal th...

The photovoltage Voc of high-performance solar cells such as GaAs and metal halide perovskites is affected by the exponential Urbach tail in absorption spectrum, with an energy parameter EU. It has been observed that increasing decreases maximum can be achieved. On basis detailed balance reciprocity emission, we present a calculation shows voltage loss due to obeys universal relation ΔVocrad = ...

We welcome the comment by Urbach and Cotton (2008) on our exploratory analysis of the consequences of sexual selection for fisheries-induced evolution (Hutchings and Rowe 2008). Two primary conclusions emerged from our work. First, irrespective of the underlying cause, fisheriesinduced evolution of traits linked to reproductive success may lead to unanticipated consequences regarding the rate a...

Lung exposure to metal oxide nanoparticles (NPs) comprising soluble metal haptens may produce T-helper cell type 1 (Th1)- and Th17-associated delayed-type hypersensitivity (DTH) responses and pulmonary alveolar proteinosis (PAP). In order to study this, haptenic metal oxide NPs (NiO, Co(3)O(4), Cr(2)O(3) and CuO) were instilled into the lungs of female Wistar rats, and the immunoinflammatory re...