Search results for "Sources"
showing 10 items of 2554 documents
Thin Film CIGS Solar Cells, Photovoltaic Modules, and the Problems of Modeling
2013
Starting from the results regarding a nonvacuum technique to fabricate CIGS thin films for solar cells by means of single-step electrodeposition, we focus on the methodological problems of modeling at cell structure and photovoltaic module levels. As a matter of fact, electrodeposition is known as a practical alternative to costly vacuum-based technologies for semiconductor processing in the photovoltaic device sector, but it can lead to quite different structural and electrical properties. For this reason, a greater effort is required to ensure that the perspectives of the electrical engineer and the material scientist are given an opportunity for a closer comparison and a common language.…
Varying plant protein sources in the diet of sea bass Dicentrarchus labrax differently affects lipid metabolism and deposition
2010
The liver activity of lipogenic enzymes, the lipid content in various tissues, and plasma lipid levels of major, were measured in sea bass (D. labrax) fed over 96 days either a, fish meal-based control diet or preparations where 70% of fish meal protein was replaced by wheat gluten singly or in combination with pea or soybean meals. Relative to the controls, sea bass fed the wheat gluten-based diet resulted in stimulated lipogenesis in liver and increased lipid deposition in muscle. The opposite occurred when a substantial amount of soybean meal was included in the diet. Mesenteric fat depots were apparently insensitive to major changes in dietary protein source in fish showing similar inta…
Quasi-periodical kinetic instabilities in minimum-B confined plasma
2022
We present the results of an experimental investigation of quasi-periodical kinetic instabilities exhibited by magnetically confined electron cyclotron resonance heated plasmas. The instabilities were detected by measuring plasma microwave emission, electron losses, and wall bremsstrahlung. The instabilities were found to be grouped into fast sequences of periodic plasma losses, separated by ∼100 µs between the bursts, followed by 1–10 ms quiescent periods before the next event. Increasing the plasma energy content by adjusting the plasma heating parameters, in particular the magnetic field strength, makes the instabilities more chaotic in the time domain. Statistical analysis reveals that …
Recent progress on the superconducting ion source VENUS.
2012
The 28 GHz Ion Source VENUS (versatile ECR for nuclear science) is back in operation after the superconducting sextupole leads were repaired and a fourth cryocooler was added. VENUS serves as an R&D device to explore the limits of electron cyclotron resonance source performance at 28 GHz with its 10 kW gryotron and optimum magnetic fields and as an ion source to increase the capabilities of the 88-Inch Cyclotron both for nuclear physics research and applications. The development and testing of ovens and sputtering techniques cover a wide range of applications. Recent experiments on bismuth demonstrated stable operation at 300 eμA of Bi31+, which is in the intensity range of interest for hig…
The electron cyclotron resonance ion source with arc-shaped coils concept
2012
The main limitation to further improve the performance of ECR ion sources is set by the magnet technology related to the multipole magnet field used for the closed minimum-B structure. The JYFL ion source group has sought different approaches to improve the strength of the minimum-B structure required for the production of highly charged ion beams. It was found out that such a configuration can be realized with arc shaped coils. The first prototype, electron cyclotron resonance ion source with arc-shaped coils (ARC-ECRIS), was constructed and tested at JYFL in 2006. It was confirmed that such an ion source can be used for the production of highly charged ion beams. Regardless of several cos…
The relationship between visible light emission and species fraction of the hydrogen ion beams extracted from 2.45 GHz microwave discharge.
2015
The relationship between Balmer-α and Fulcher-band emissions with extracted H + , H + 2 , and H + 3 ions is demonstrated for a 2.45 GHz microwave discharge. Ion mass spectra and optical measurements of Balmer-α and Fulcher-band emissions have been obtained with a Wien Filter having an optical viewport on the plasma chamber axis. The beam of approximately 1 mA is analyzed for different plasma conditions simultaneously with the measurement of light emissions both with temporal resolution. The use of visible light emissions as a valuable diagnostic tool for monitoring the species fraction of the extracted beams is proposed. peerReviewed
Photoelectron emission experiments with ECR-driven multi-dipolar negative ion plasma source
2017
Photoelectron emission measurements have been performed using a 2.45 GHz ECR-driven multi-dipolar plasma source in a low pressure hydrogen discharge. Photoelectron currents induced by light emitted from ECR zone and H− production region are measured from Al, Cu, Mo, Ta, and stainless steel (SAE 304) surfaces as a function of microwave power and neutral hydrogen pressure. The total photoelectron current from the plasma chamber wall is estimated to reach values up to 1 A for 900 W of injected microwave power. It is concluded that the volumetric photon emission rate in wavelength range relevant for photoelectron emission is a few times higher in arc discharge. peerReviewed
VUV emission spectroscopy combined with H- density measurements in the ion source Prometheus I
2016
“Prometheus I” is a volume H− negative ion source, driven by a network of dipolar electron cyclotron resonance (ECR; 2.45 GHz) modules. The vacuum-ultraviolet (VUV) emission spectrum of low-temperature hydrogen plasmas may be related to molecular and atomic processes involved directly or indirectly in the production of negative ions. In this work, VUV spectroscopy has been performed in the above source, Prometheus I, both in the ECR zones and the bulk (far from ECR zones and surfaces) plasma. The acquired VUV spectra are correlated with the negative ion densities, as measured by means of laser photodetachment, and the possible mechanisms of negative ion production are considered. The well-e…
Facile and efficient chemical functionalization of aliphatic polyesters by cross metathesis
2016
International audience; An effective preparation of new tailor-made macromolecular materials via a combination of two (atom-efficient) catalytic transformations is reported. First, new aliphatic polyesters with alternated composition have been prepared using a salen aluminum catalyst system. Next, the pendant vinyl moieties in those copolymers have been selectively transformed into various functional groups by metathesis in the presence of homogeneous Grubbs catalysts. The latter metathesis reaction has been optimized in terms of catalytic activity and selectivity, to define the conditions for an effective and safe procedure that does not affect the macromolecular architecture. All polymer …