Interactions Between a Condensed Target and a Non-Equilibrium Plasma: Acid-Base Reactions at the Interface

A new approach of plasma processes of industrial use is presented, with emphasis on the chemical properties of the plasma gas. Reactions occurring at the gas/target interface are for the first time interpreted in terms of acid-base reactions and pertinent examples are given of laboratory experiments and of industrial treatments (e. g., etching, plasma polymerization or surface modification processes). Proton exchanges between the plasma phase and an aqueous target gives evidence of Bronsted acid-base phenomena. Illustrations of Lewis acid-base characters are provided by the role of biradicals (e.g., halogenocarbenes, nitrenc) which are the main reacting species in etching or in surface treatment processes

On the groove pressing of Ni-W alloy: microstructure, texture and mechanical properties evolution

International audienceThe microstructure, texture and mechanical properties of the Ni-14%W(wt.%) alloy with two different initial grain sizes and textures were investigated after groove pressing (GP) at 450 °C to 4 cycles using Electron Back Scatter Diffraction (EBSD) and microhardness measurements. The initial first series was characterized by small equiaxed grains and Cube dominant texture component. The second series has elongated grains and β-fiber texture. EBSD analysis has shown that GP processing led to a slight refinement (less than 15%) of equiaxed grains in series I while greater refinement (~55%) of the mean spacing along normal direction was observed in series II. The texture did not drastically change from the initial ones and was characterized by the weakening of the Cube component in series I and rapid decrease of Copper component for series II. GP processing reduces very slightly the plastic anisotropy of the alloy with initial elongated granular microstructure

Synthesis, electrochemical and photochromic behaviour of a series of (1,4-dithiafulven-6-yl)substituted 3H-naphtho[2,1-b]pyran derivatives

The synthesis and electrochemical and photochromic properties of new 3,3-diphenyl-8-(1,4-dithiafulven-6-yl)-[3H]-naphtho[2,1-b]pyran derivatives containing differently substituted dithiafulvenyl units are described. An example of electrochemical dimerization is shown which gives access to electroactive bichromophoric systems. Such systems could allow the study of the interplay of photochromic and electrochemical properties

QTL analysis of the genetic architecture determining resistance to fire blight in an apple progeny

Fire blight, caused by the bacterial pathogen Erwinia amylovora, is one of the most destructive diseases of apple (Malus x domestica). In order to analyse the genetic determinism of resistance to fire blight in apple, a quantitative trait analysis (QTL) approach was used. A F1 progeny of 164 individuals derived from a cross between the apple cultivars `Prima¿ and `Fiesta¿ was inoculated in greenhouse conditions. Seven copies per genotype were used. The length of the necrosis observed on shoots was scored 7 and 14 days after inoculation. The MapQTL software was used for QTL analyses, using two previously built maps of the parents, and the symptoms scored on shoots. Digenic interactions between all pairwise combinations of genetic markers were tested using a two-way ANOVA model with the SAS software. QTL were detected at the same locations both 7 and 14 days after inoculation. Two weak effect QTL deriving from `Prima¿ were detected on linkage groups (LG) 3 and LG16. One strong effect QTL deriving from `Fiesta¿ was detected on LG7 that explained 46.6% of the phenotypic variation observed in the progeny. Two additional significant (

Additive layer manufacturing of titanium matrix composites using the direct metal deposition laser process

Titanium Matrix Composites (TMC's) containing various volume fractions of (TiB+TiC) particles have been deposited from powder feedstocks consisting of a blend of pre-alloyed (Ti-6Al-4V+B4C) powders, using the direct metal deposition (DMD) laser process and the in-situ chemical reaction 5Ti+B4C→4TiB+TiC. Process optimization has allowed to obtain a homogeneous distribution of tiny TiB whiskers within the Ti-6Al-4V α/β matrix, with a full solubilization of C for low B4C contents (0.5 wt% and 1.5 wt%), and the formation of a small amount of globular TiC particles at higher B4C content (3%). Comparisons with Ti-6Al-4V DMD walls revealed a substantial grain refinement on TMC's due to enhanced grain nucleation on TiB whiskers, even for low B4C contents. Last, mechanical investigations indicated an increase of 10–15% of Vickers hardness, and a constant 10% increase of Young modulus on a large temperature range (20–600 °C) for all B4C conten

Identification of a major QTL together with several minor additive or epistatic QTLs for resistance to fire blight in apple in two related progenies

Although fire blight, caused by the bacterium Erwinia amylovora, is one of the most destructive diseases of apple (Malus x domestica) worldwide, no major, qualitative gene for resistance to this disease has been identified to date in apple. We conducted a quantitative trait locus (QTL) analysis in two F-1 progenies derived from crosses between the cultivars Fiesta and either Discovery or Prima. Both progenies were inoculated in the greenhouse with the same strain of E. amylovora, and the length of necrosis was scored 7 days and 14 days after inoculation. Additive QTLs were identified using the MAPQTL software, and digenic epistatic interactions, which are an indication of putative epistatic QTLs, were detected by two-way analyses of variance. A major QTL explaining 34.3-46.6% of the phenotypic variation was identified on linkage group (LG) 7 of Fiesta in both progenies at the same genetic position. Four minor QTLs were also identified on LGs 3, 12 and 13. In addition, several significant digenic interactions were identified in both progenies. These results confirm the complex polygenic nature of resistance to fire blight in the progenies studied and also reveal the existence of a major QTL on LG7 that is stable in two distinct genetic backgrounds. This QTL could be a valuable target in marker-assisted selection to obtain new, fire blight-resistant apple cultivars and forms a starting point for discovering the function of the genes underlying such QTLs involved in fire blight control