89,495 research outputs found
Defect Detection in Thin-film Photovoltaics; Towards Improved Efficiency and Longevity
No full textThe photovoltaic (PV) industry is seeking to increase efficiency and functional lifetime of PV modules manufactured on polymer substrates. High resolution and high speed surface inspection for the quality control of the manufacture of large area flexible PV modules are necessary to guarantee maximum quality, longer lifetime and enhanced product yield. Flexible PV films are the newest development in the renewable energy field and the latest films have efficiencies at or beyond the level of Si-based rigid PV modules. These modules are fabricated on polymer film by the repeated deposition, and patterning, of thin layer materials using roll-to-roll technology. However, they are at present highly susceptible to long term environmental degradation as a result of water vapor transmission through the protective encapsulation to the active layer. To reduce the WVTR the PV encapsulation includes a barrier layer of amorphous Al2O3 on a planarised polymer substrate. This highly conformal barrier layer is produced by atomic layer deposition (ALD). Nevertheless water vapour transmission is still facilitated by the presence of micro and nano-scale defects in these barriers which results in decreased cell efficiency and reduced longevity.
Analytical techniques including: White Light Scanning Interferometry (WLSI), Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) were used to characterise the water vapor barrier defects. Areal surface texture parameter analysis allows the efficient separation of small insignificant features from significant defects. This parametric analysis is then correlated with the water vapour transmission rate as measured on typical sets of films using standard MOCON test. The paper finishes by drawing conclusions based on analysis of WVTR and defect size, density and distribution, where it is postulated that small numbers of large features have more influence on the deterioration of water vapor transmission rates than large numbers of small features. This result provides the basis for developing roll-to-roll in process metrology devices for quality control
Defect Detection in Thin-film Photovoltaics; Towards Improved Efficiency and Longevity
No full textThe photovoltaic (PV) industry is seeking to increase efficiency and functional lifetime of PV modules manufactured on polymer substrates. High resolution and high speed surface inspection for the quality control of the manufacture of large area flexible PV modules are necessary to guarantee maximum quality, longer lifetime and enhanced product yield. Flexible PV films are the newest development in the renewable energy field and the latest films have efficiencies at or beyond the level of Si-based rigid PV modules. These modules are fabricated on polymer film by the repeated deposition, and patterning, of thin layer materials using roll-to-roll technology. However, they are at present highly susceptible to long term environmental degradation as a result of water vapor transmission through the protective encapsulation to the active layer. To reduce the WVTR the PV encapsulation includes a barrier layer of amorphous Al2O3 on a planarised polymer substrate. This highly conformal barrier layer is produced by atomic layer deposition (ALD). Nevertheless water vapour transmission is still facilitated by the presence of micro and nano-scale defects in these barriers which results in decreased cell efficiency and reduced longevity.
Analytical techniques including: White Light Scanning Interferometry (WLSI), Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) were used to characterise the water vapor barrier defects. Areal surface texture parameter analysis allows the efficient separation of small insignificant features from significant defects. This parametric analysis is then correlated with the water vapour transmission rate as measured on typical sets of films using standard MOCON test. The paper finishes by drawing conclusions based on analysis of WVTR and defect size, density and distribution, where it is postulated that small numbers of large features have more influence on the deterioration of water vapor transmission rates than large numbers of small features. This result provides the basis for developing roll-to-roll in process metrology devices for quality control
A computerised data handling procedure for defect detection and analysis for large area substrates manufactured by roll-to-roll process
No full textThe development of optical on-line/in-process surface inspection and characterisation systems for flexible roll to roll (R2R) thin film barriers used for photo-voltaic (PV) modules is a core research goal for the EU funded NanoMend project. Micro and nano scale defects in the ALD (atomic layer deposition) Al2O3 barrier coating produced by R2R techniques can affect the PV module efficiency and lifespan. The presence of defects has been shown to have a clear correlation with the water-vapour-transmission-rate (WVTR). Hence, in order to improve the PV cell performance and lifespan the barrier film layer must prevent water vapour ingress. One of the main challenges for the application of in process metrology is how to assess large and multiple measurement data sets obtained from an in process optical instrument. Measuring the surface topography over large area substrates (approximately 500 mm substrate width) with a limited field-of-view (FOV) of the optical instrument will produce hundreds/thousands of measurement files. Assessing each file individually to find and analyse defects manually is time consuming and impractical. This paper reports the basis of a computerised solution to assess these files by monitoring and extracting areal surface topography parameters. Comparing parameter values to an experimentally determined threshold value, obtained from extensive lab-based measurement of Al2O3 ALD coated films, can indicate the existence of the defects within a given FOV. This process can be repeated automatically for chosen parameters and the existence of defects can be indicated for the entire set of measurement files spontaneously without interaction from the inspector. A running defect log and defect statistics associated with the captured set of data files can be generated. This paper outlines the implementation of the auto-defect logging using advanced areal parameters, and its application in a proof of concept system at the Center for Process Innovation (UK) is discussed
Mitochondrial therapy for ALD: fact or fiction?
No full textTrabajo presentado en el 18th ESBRA Congress (European Society for Biomedical Research on Alcoholism), celebraod en Timisoara (Rumanía), del 7 al 9 de octubre de 2021Alcoholic liver disease (ALD) is a major cause of chronic liver disease and a main reason of liver related death. ALD represents a spectrum of liver alterations that begin with steatosis, which can progress to alcoholic steatohepatitis (ASH) and hepatocellular carcinoma (HCC). Unfortunately, the mechanisms underlying the progression from steatosis to advanced stages of ALD are still incompletely understood. Besides the abuse of alcohol consumption and genetic determinants, nutritional factors synergize with alcohol to promote ALD progression. Cholesterol metabolism and intracelular trafficking to mitochondria have emerged as important determinants of nonalcoholic steatohepatitis and HCC development. As steroidogenic acute regulatory protein (STARD1) govern the trafficking of cholesterol to mitochondrial inner membrane for metabolism, we examined the regulation of STARD1 in ALD and if its expression occurs in a zonal-dependent fashion. Immunohistochemical analyses of liver sections of patients with ALD or mice fed alcohol revealed a predominant expression of STARD1 in areas stained with glutamine synthase (perivenous zone) but not with CYP2F2 (periportal zone). These findings were confirmed in isolated periportal (PP) and perivenous (PV) hepatocytes from mice fed alcohol. Evidence of alcohol-induced oxidative stress, mitochondrial cholesterol accumulation and mitochondrial dysfunction was predominantly seen in PV hepatocytes, and was ameliorated in PV from Stard1ΔHep mice fed alcohol. To address the mechanism of STARD1 upregulation in ALD, we addressed the role of hypoxia. Primary mouse hepatocytes cultured under 2% O2 or cobaltous chloride exhibited increased expression of STARD1. Moreover, mice with hepatocyte-specific Vhl knockdown by AAV-TBG-Cre administration to Vhlf/f mice, resulted in increased expression of HIF-1/HIF-2 and a marked upregulation of STARD1. Consequently, AAV-TBG-Cre-treated Vhlf/f mice developed ASH compared to AAV-TBG-GFP-treated Vhlf/f mice, and this outcome was ameliorated by simultaneous hepatocyte-specific Stard1 knockdown (Vhlf/f/Stard1f/f mice treated with AAV-TBG-Cre). Thus, STARD1 is selectively expressed in the perivenous zone in ALD and this event is determined in part through the presence of HRE in the STARD1 promoter.Peer reviewe
Exploitation of Atomic Layer Deposition (ALD) technique for the synthesis of inorganic nanostructured thin films
No full textAtomic Layer Deposition (ALD), belonging to Chemical Vapor Deposition (CVD) techniques, is an attractive
process for the manufacturing of nanostructured thin films, with thickness down to a fraction of a monolayer.
It is a powerful and unique technique that has achieved a lot of interest: it allows the deposition of high
quality thin films with atomic level control and high conformal coverage even on complex shaped surfaces
[1]. The advantages of ALD method include low impurity content, pinhole-free deposition, and low processing
temperature (LT-ALD), so permitting the employment of temperature-sensitive substrates [2]. The basics of
the technique and an overview of its potentiality are here presented
Further Development of Surface Metrology Methods for Predicting the Functional Performance of Flexible PV Barrier Films
No full textSurface topography analysis plays a very significant role in determining the functional performance for many engineering surfaces. In this paper, feature characterisation techniques, based on the ‘Wolf pruning’ method are implemented to characterise micro and nano-scale features which have a dominant effect on the functional lifespan of flexible Photovoltaic (PV) modules. The densities and dimensions of the potential significant features are calculated by means of the feature “characterisation toolbox”. The outcome of this study has shown the potential of areal feature segmentation for detecting functionally significant defects present in Atomic Layer Deposition (ALD) barrier coatings of Al2O3 on polymer films. The analysis provides the basis for the development in process metrology for Roll-to-Roll (R2R) production of barrier coatings as applied to flexible PV arrays and is a first step in the demonstration of in-process use of feature parameters
Review Article: Recommended reading list of early publications on atomic layer deposition—Outcome of the “Virtual Project on the History of ALD”
No full textAtomic layer deposition (ALD), a gas-phase thin film deposition technique based on repeated,
self-terminating gas–solid reactions, has become the method of choice in semiconductor
manufacturing and many other technological areas for depositing thin conformal inorganic material
layers for various applications. ALD has been discovered and developed independently, at
least twice, under different names: atomic layer epitaxy (ALE) and molecular layering. ALE, dating
back to 1974 in Finland, has been commonly known as the origin of ALD, while work done
since the 1960s in the Soviet Union under the name “molecular layering” (and sometimes other
names) has remained much less known. The virtual project on the history of ALD (VPHA) is a
volunteer-based effort with open participation, set up to make the early days of ALD more transparent.
In VPHA, started in July 2013, the target is to list, read and comment on all early ALD
academic and patent literature up to 1986. VPHA has resulted in two essays and several presentations
at international conferences. This paper, based on a poster presentation at the 16th
International Conference on Atomic Layer Deposition in Dublin, Ireland, 2016, presents a recommended
reading list of early ALD publications, created collectively by the VPHA participants
through voting. The list contains 22 publications from Finland, Japan, Soviet Union, United
Kingdom, and United States. Up to now, a balanced overview regarding the early history of ALD
has been missing; the current list is an attempt to remedy this deficiency.peerReviewe
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
MBL modulates ALD-DNA–induced macrophage M2b polarization.
No full text<p>ALD-DNA was pre-incubated with indicated mouse MBL for 2 h. RAW264.7 cells or peritoneal macrophages were cultured with PBS, ALD-DNA or ALD-DNA/MBL complexes for 24 h. (A and C) mRNA levels of TNF-α, MCP-1, IL-6 and IL-10 in RAW264.7 cells or peritoneal macrophages were analyzed by real-time PCR. (B and D) Protein levels of TNF-α, MCP-1, IL-6 and IL-10 in the supernatants of RAW264.7 cells or peritoneal macrophages were measured by ELISA. (E and F) RAW264.7 cells were cultured with PBS, ALD-DNA or ALD-DNA/MBL complexes for 24 h. Then cell lysates were prepared to measure the protein levels of iNOS by western blot analysis. All values are given relative to the expression level of the β-actin. Data are means ± SD of three independent experiments. *<i>p</i><0.05; **<i>p</i><0.01; ***<i>p</i><0.001.</p
Scatterplot of associations of genetically predicted of BMDs on the risk of ALD and NAFLD.
No full textScatterplot of associations of genetically predicted of TB-BMD on the risk of A)ALD;B) NAFLD; Scatterplot of associations of genetically predicted of FN-BMD on the risk of C)ALD;D) NAFLD; Scatterplot of associations of genetically predicted of LS-BMD on the risk of E)ALD;F) NAFLD; Scatterplot of associations of genetically predicted of FA-BMD on the risk of G)ALD;H) NAFLD. (PDF)</p
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