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Search Results: 1 - 10 of 219556 matches for " C. Aberle "
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Optical Properties of Quantum-Dot-Doped Liquid Scintillators
C. Aberle,J. J. Li,S. Weiss,L. Winslow
Physics , 2013, DOI: 10.1088/1748-0221/8/10/P10015
Abstract: Semiconductor nanoparticles (quantum dots) were studied in the context of liquid scintillator development for upcoming neutrino experiments. The unique optical and chemical properties of quantum dots are particularly promising for the use in neutrinoless double beta decay experiments. Liquid scintillators for large scale neutrino detectors have to meet specific requirements which are reviewed, highlighting the peculiarities of quantum-dot-doping. In this paper, we report results on laboratory-scale measurements of the attenuation length and the fluorescence properties of three commercial quantum dot samples. The results include absorbance and emission stability measurements, improvement in transparency due to filtering of the quantum dot samples, precipitation tests to isolate the quantum dots from solution and energy transfer studies with quantum dots and the fluorophore PPO.
Recent Advances in Solar Cells
Armin Aberle
Advances in OptoElectronics , 2008, DOI: 10.1155/2007/60319
Abstract:
Measuring Directionality in Double-Beta Decay and Neutrino Interactions with Kiloton-Scale Scintillation Detectors
C. Aberle,A. Elagin,H. J. Frisch,M. Wetstein,L. Winslow
Physics , 2013, DOI: 10.1088/1748-0221/9/06/P06012
Abstract: Large liquid-scintillator-based detectors have proven to be exceptionally effective for low energy neutrino measurements due to their good energy resolution and scalability to large volumes. The addition of directional information using Cherenkov light and fast timing would enhance the scientific reach of these detectors, especially for searches for neutrino-less double-beta decay. In this paper, we develop a technique for extracting particle direction using the difference in arrival times for Cherenkov and scintillation light, and evaluate several detector advances in timing, photodetector spectral response, and scintillator emission spectra that could be used to make direction reconstruction a reality in a kiloton-scale detector.
Large scale Gd-beta-diketonate based organic liquid scintillator production for antineutrino detection
C. Aberle,C. Buck,B. Gramlich,F. X. Hartmann,M. Lindner,S. Sch?nert,U. Schwan,S. Wagner,H. Watanabe
Physics , 2011, DOI: 10.1088/1748-0221/7/06/P06008
Abstract: Over the course of several decades, organic liquid scintillators have formed the basis for successful neutrino detectors. Gadolinium-loaded liquid scintillators provide efficient background suppression for electron antineutrino detection at nuclear reactor plants. In the Double Chooz reactor antineutrino experiment, a newly developed beta-diketonate gadolinium-loaded scintillator is utilized for the first time. Its large scale production and characterization are described. A new, light yield matched metal-free companion scintillator is presented. Both organic liquids comprise the target and "Gamma Catcher" of the Double Chooz detectors.
Polycrystalline Silicon Thin-Film Solar Cells on AIT-Textured Glass Superstrates
Per I. Widenborg,Armin G. Aberle
Advances in OptoElectronics , 2007, DOI: 10.1155/2007/24584
Abstract: A new glass texturing method (AIT—aluminium-induced texturisation) has recently been developed by our group. In the present work, the potential of this method is explored by fabricating PLASMA poly-Si thin-film solar cells on glass superstrates that were textured with the AIT method. Using an interdigitated metallisation scheme with a full-area Al rear contact, PLASMA cells with an efficiency of up to 7% are realised. This promising result shows that the AIT glass texturing method is fully compatible with the fabrication of poly-Si thin-film solar cells on glass using solid phase crystallisation (SPC) of PECVD-deposited amorphous silicon precursor diodes. As such, there are now two distinctly different glass texturing methods—the AIT method and CSG Solar's glass bead method—that are known to be capable of producing efficient SPC poly-Si thin-film solar cells on glass.
Experimental Assessment of the Role of Acetaldehyde in Alcoholic Cardiomyopathy
Aberle II Nicholas S.,Ren Jun
Biological Procedures Online , 2003, DOI: 10.1251/bpo41
Abstract: Alcoholism is one of the major causes of non-ischemic heart damage. The myopathic state of the heart due to alcohol consumption, namely alcoholic cardiomyopathy, is manifested by cardiac hypertrophy, compromised ventricular contractility and cardiac output. Several mechanisms have been postulated for alcoholic cardiomyopathy including oxidative damage, accumulation of triglycerides, altered fatty acid extraction, decreased myofilament Ca2+ sensitivity, and impaired protein synthesis. Despite intensive efforts to unveil the mechanism and ultimate toxin responsible for alcohol-induced cardiac toxicity, neither has been clarified thus far. Primary candidates for the specific toxins are ethanol, its first and major metabolic product - acetaldehyde (ACA) and fatty acid ethyl esters. Evidence from our lab suggests that ACA directly impairs cardiac function and promotes lipid peroxidation resulting in oxidative damage. The ACA-induced cardiac contractile depression may be reconciled with inhibitors of Cytochrome P-450 oxidase, xanthine oxidase and lipid peroxidation Unfortunately, the common methods to investigate the toxicity of ACA have been hampered by the fact that direct intake of ACA is toxic and unsuitable for chronic study, which is unable to provide direct evidence of direct cardiac toxicity for ACA. In order to overcome this obstacle associated with the chemical properties of ACA, our laboratory has used the chronic ethanol feeding model in transgenic mice with cardiac over-expression of alcohol dehydrogenase (ADH) and an in vitro ventricular myocyte culture model. The combination of both in vivo and in vitro approaches allows us to evaluate the role of ACA in ethanol-induced cardiac toxicity and certain cellular signaling pathways leading to alcoholic cardiomyopathy.
Complications, Mineral and Vitamin Deficiencies: Comparison between Roux-en-Y Gastric Bypass and Sleeve Gastrectomy  [PDF]
Nina Sauer, Jan Wienecke, Clarissa Schulze zur Wiesfch, Stefan Wolter, Oliver Mann, Jens Aberle
Surgical Science (SS) , 2013, DOI: 10.4236/ss.2013.412106
Abstract:

Objective: Nutritional deficiencies are known side-effects of bariatric surgeries, specifically in those that bypass the proximal intestine. Therefore, in clinical practice, vitamin and mineral supplementations are often necessary after such operations. It was our intention to evaluate, whether alimentary deficiencies occur with the same frequency in patients following Sleeve-Gastrectomy (SG) compared to Roux-en-Y Gastric Bypass (RYGB) surgeries. Methods: We conducted a retrospective data analysis of 171 patients (121 RYGB, 50 SG). Vitamin levels were compared between SG and RYGB patients over the first post-operative year. Furthermore, regression analysis was performed with regard to vitamin and iron supplementations and their recommended dosages. Complications occurring within the first post-surgical year were documented as well. Results: Other than vitamin B6 deficiency, which was found to be more frequent in SG patients, there was no other significant difference regarding the type of operation and the number of patients who had these deficiencies. There was no significant difference in average vitamin and iron levels between RYGB and SG. A minimum dose of 1000 IU vitamin D per day was necessary to affect vitamin D levels. The intramuscular administration of vitamin B12 was the only route found to be effective. Complications within the first year were rare. Conclusions: Against common assumptions, vitamin and iron deficiencies in SG patients are not less frequent in the first post-surgical year in comparison to RYGB patients. Standard supplementations should include iron in premenopausal women: Vitamin D at least 1000 IU per day and vitamin B12 i.m. administration in case of a deficiency.

Detailed Micro Raman Spectroscopy Analysis of Doped Silicon Thin Film Layers and Its Feasibility for Heterojunction Silicon Wafer Solar Cells  [PDF]
Z. P. Ling, J. Ge, R. Stangl, A. G. Aberle, T. Mueller
Journal of Materials Science and Chemical Engineering (MSCE) , 2013, DOI: 10.4236/msce.2013.15A001
Abstract:

Hydrogenated doped silicon thin films deposited using RF (13.56 MHz) PECVD were studied in detail using micro Raman spectroscopy to investigate the impact of doping gas flow, film thickness, and substrate type on the film characteristics. In particular, by deconvoluting the micro Raman spectra into amorphous and crystalline components, qualitative and quantitative information such as bond angle disorder, bond length, film stress, and film crystallinity can be determined. By selecting the optimum doped silicon thin film deposition conditions, and combining our p-doped and n-doped silicon thin films in different heterojunction structures, we demonstrate both (i) an efficient field effect passivation and (ii) further improvement to c-Si/a-Si:H(i) interface defect density with observed improvement in implied open-circuit voltage VOC and minority carrier lifetimes across all injections levels of interest. In particular, the heterojunction structure (a-Si:H(p)/a-Si:H(i)/c-Si(n)/a-Si:H(i)/a-Si:H(p)) demonstrates a minority carrier lifetime of 2.4 ms at an injection level of 1015 cm-3, and a high implied open-circuit voltage of 725 mV. Simulation studies reveal a strong dependence of the interface defect density Dit on the heterojunction silicon wafer solar cell performance, affected by the deposition conditions of the overlying doped silicon thin film layers. Using our films, and a fitted Dit of 5 × 1010 cm-2·eV-1

A new method for imaging nuclear threats using cosmic ray muons
C. L. Morris,Jeffrey Bacon,Konstantin Borozdin,Haruo Miyadera,John Perry,Evan Rose,Scott Watson,Timothy White,Derek Aberle,J. Andrew Green,George G. McDuff,Zarija Luki?,Edward C. Milner
Physics , 2013,
Abstract: Muon tomography is a technique that uses cosmic ray muons to generate three dimensional images of volumes using information contained in the Coulomb scattering of the muons. Advantages of this technique are the ability of cosmic rays to penetrate significant overburden and the absence of any additional dose delivered to subjects under study above the natural cosmic ray flux. Disadvantages include the relatively long exposure times and poor position resolution and complex algorithms needed for reconstruction. Here we demonstrate a new method for obtaining improved position resolution and statistical precision for objects with spherical symmetry.
Rapid Thermal Annealing and Hydrogen Passivation of Polycrystalline Silicon Thin-Film Solar Cells on Low-Temperature Glass
Mason L. Terry,Daniel Inns,Armin G. Aberle
Advances in OptoElectronics , 2007, DOI: 10.1155/2007/83657
Abstract: The changes in open-circuit voltage (Voc), short-circuit current density (Jsc), and internal quantum efficiency (IQE) of aLuminum induced crystallization, ion-assisted deposition (ALICIA) polycrystalline silicon thin-film solar cells on low-temperature glass substrates due to rapid thermal anneal (RTA) treatment and subsequent remote microwave hydrogen plasma passivation (hydrogenation) are examined. Voc improvements from 130 mV to 430 mV, Jsc improvements from 1.2 mA/cm2 to 11.3 mA/cm2, and peak IQE improvements from 16% to > 70% are achieved. A 1-second RTA plateau at 1000°C followed by hydrogenation increases the Jsc by a factor of 5.5. Secondary ion mass spectroscopy measurements are used to determine the concentration profiles of dopants, impurities, and hydrogen. Computer modeling based on simulations of the measured IQE data reveals that the minority carrier lifetime in the absorber region increases by 3 orders of magnitude to about 1 nanosecond (corresponding to a diffusion length of at least 1 μm) due to RTA and subsequent hydrogenation. The evaluation of the changes in the quantum efficiency and Voc due to RTA and hydrogenation with computer modeling significantly improves the understanding of the limiting factors to cell performance.
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