Thermal stability of titanium nitride for shallow junction solar cell contacts

To demonstrate the thermal stability of titanium nitride as a high-temperature diffusion barrier, the TiN-Ti-Ag metallization scheme has been tested on shallow-junction (~2000 Å) Si solar cells. Electrical measurements on reference samples with the Ti-Ag metallization scheme show serious degradation after a 600 °C, 10-min annealing. With the TiN-Ti-Ag scheme, no degradation of cell performance is observed after the same heat treatment if the TiN layer is >~1700 Å. The glass encapsulation of cells by electrostatic bonding requires such a heat treatment

Investigation of titanium-nitride layers for solar-cell contacts

Reactively sputtered titanium-nitride layers have been incorporated as diffusion barriers in a titanium-silver metallization scheme on silicon, Backscattering analysis (2-MeV He+, RBS) indicates that the integrity of the system is basically preserved during annealing at 600° for 10 min. Electrical properties were determined for titanium-nitride layers prepared under different deposition conditions. Resistivity and Hall mobility appear to depend on the oxygen contamination of the deposited material. For the lowest oxygen concentration (<5 at %) a resistivity of 170 µΩ . cm has been found

Comportamento ad alta temperatura di rivestimenti NiCrAlY prodotti mediante tecnica Laser Cladding

La tecnica Laser Cladding è un metodo alternativo alla spruzzatura termica per la produzione di rivestimentiresistenti alle alte temperature con una porosità molto bassa o addirittura nulla.Il presente studio ha riguardato il comportamento ad ossidazione di rivestimenti NiCrAlY ottenuti medianteLaser Cladding su substrati di Hastelloy X. Il comportamento ad ossidazione dei campioni rivestiti è statovalutato mediante prove in forno a circolazione d’aria alla temperatura di 1100°C con durate fino a 450 ore.I rivestimenti sono stati analizzati, prima e dopo le prove di ossidazione, mediante tecniche di microscopiaottica ed elettronica, microanalisi e diffrazione di raggi X. Dopo la deposizione il rivestimento ha mostratouna struttura dendritica con grani colonnari e porosità pressoché nulla. Dopo le prove di ossidazione l’analisimicroscopica ha mostrato la presenza di due distinti strati di ossidi, uno più esterno costituitoprevalentemente da ossidi di tipo spinello e uno strato più interno, continuo, costituito principalmenteda allumina. I risultati ottenuti suggeriscono che il rivestimento di NiCrAlY preparato per Laser Claddingè in grado di formare, ad alte temperature ed in atmosfera ossidativa, uno strato continuo di alluminache può proteggere il substrato dall’ossidazione

Studio per lo sviluppo di nuovi rivestimenti ceramico compositi impiegabili in sistemi abradibili

Una strategia per l’incremento delle prestazioni delle turbine a gas consiste nella riduzione del trafilamentodei gas nella zona ad alta temperatura della turbomacchina grazie alla riduzione della distanza tra lasommità delle palette e la copertura protettiva della cassa della turbina. A tal fine sono stati studiati sistemiabradibili realizzati mediante diverse tecniche. Sono stati realizzati sistemi compositi compositi a baseCoNiCrAlY/Al2O3 mediante tecnica Air Plasma Spray (APS), a base NiCrAlY/graphite mediante tecnica LaserCladding e barriere termiche spesse e porose. Le resistenze all’ossidazione e alla fatica termica dei rivestimentisono state valutate per mezzo di prove di ossidazione isoterma e ciclica. I rivestimenti compositiCoNiCrAlY/Al2O3 e NiCrAlY/graphite dopo 1000 ore a 1100°C non hanno mostrato rilevanti modificazionimicrostrutturali. La resistenza all’ossidazione dei nuovi rivestimenti compositi soddisfa le specifiche deiproduttori, gli “Original Equipment Manufacturer” (OEM). Le barriere termiche spesse e porose superano i testdi fatica termica imposti dalle procedure degli OEM. La durezza di tali rivestimenti suggerisce il loro uso incombinazione con palette dotate di rivestimento abrasivo sull’estremità. Le barriere termiche hanno mostratobuone caratteristiche di abradibilità

Going through it together: Dyadic associations between parents' birth experience, relationship satisfaction, and mental health

BACKGROUND: Previous research suggests that a negative birth experience is associated with symptoms of postpartum depression and anxiety in mothers and partners. However, this has mostly been investigated within the first year postpartum and research on the long-term effects is lacking. Additionally, the role of relationship satisfaction and the interdependence between parents have not been considered so far. METHODS: Couples (N = 1992) completed questionnaires on their birth experience, relationship satisfaction, and symptoms of depression and anxiety at two months, 14 months, and two years after birth, respectively. RESULTS: Actor-Partner Interdependence Mediation Models indicated no partner effects, but several significant actor and indirect effects. A more positive birth experience was associated with higher relationship satisfaction and less depression and anxiety symptoms for both parents. Higher relationship satisfaction was in turn associated with less depression (mothers and partners) and anxiety symptoms (mothers). The association between birth experience and depression symptoms was partially mediated by relationship satisfaction for mothers and partners, while the association between birth experience and anxiety symptoms was partially mediated by relationship satisfaction only for mothers. LIMITATIONS: Due to the highly educated, very healthy sample with low levels of depression and anxiety as well as high relationship satisfaction, results cannot be generalized to less privileged parents. Moreover, all effects were very small. CONCLUSIONS: Results highlight the importance of a positive birth experience for parents' relationship satisfaction and mental health. Negative birth experiences need to be avoided to prevent a negative impact on the whole family

Methyl-binding domain protein-based DNA isolation from human blood serum combines DNA analyses and serum-autoantibody testing

<p>Abstract</p> <p>Background</p> <p>Circulating cell free DNA in serum as well as serum-autoantibodies and the serum proteome have great potential to contribute to early cancer diagnostics via non invasive blood tests. However, most DNA preparation protocols destroy the protein fraction and therefore do not allow subsequent protein analyses. In this study a novel approach based on methyl binding domain protein (MBD) is described to overcome the technical difficulties of combining DNA and protein analysis out of one single serum sample.</p> <p>Methods</p> <p>Serum or plasma samples from 98 control individuals and 54 breast cancer patients were evaluated upon silica membrane- or MBD affinity-based DNA isolation via qPCR targeting potential DNA methylation markers as well as by protein-microarrays for tumor-autoantibody testing.</p> <p>Results</p> <p>In control individuals, an average DNA level of 22.8 ± 25.7 ng/ml was detected applying the silica membrane based protocol and 8.5 ± 7.5 ng/ml using the MBD-approach, both values strongly dependent on the serum sample preparation methods used. In contrast to malignant and benign tumor serum samples, cell free DNA concentrations were significantly elevated in sera of metastasizing breast cancer patients. Technical evaluation revealed that serum upon MBD-based DNA isolation is suitable for protein-array analyses when data are consistent to untreated serum samples.</p> <p>Conclusion</p> <p>MBD affinity purification allows DNA isolations under native conditions retaining the protein function, thus for example enabling combined analyses of DNA methylation and autoantigene-profiles from the same serum sample and thereby improving minimal invasive diagnostics.</p