Effect of diamond particles on the microstructure and composition of pulse plated multilayer Ni-W/diamond composite coatings

The research encompasses the fabrication of multilayer Ni-Wdiamond composite deposits by pulse current electrodeposition. The mean surface diameter of the diamond used for the research was 0.9 microns. The composites were fabricated under various conditions and characterized by means of SEM, EDS and XRD to investigate and analyze their microstructure, grain size and elemental distribution along with variations in morphology under different conditions. The effect of variations in forward and reverse current density along with duty cycle and the combination of various aforesaid conditions on the coatings were studied and analyzed

Polycrystalline {\gamma}-boron: As hard as polycrystalline cubic boron nitride

The Vickers hardness of polycrystalline {\gamma}-B was measured using a diamond indentation method. The elastic properties of polycrystalline {\gamma}-B (B=213.9 GPa, G=227.2 GPa, and E=503.3 GPa) were determined using ultrasonic measurement at ambient condition. Under the loading force up to 20 N, our test gave an average Vickers hardness in the asymptotic-hardness region of 30.3 GPa. The average fracture toughness was measured as 4.1MPa m1/2. Additionally, We also measured the hardness and elastic properties of polycrystalline {\beta}-B and PcBN for comparison. The hardness and elastic properties for polycrystalline {\gamma}-B was found to be very close to that of PcBN. Our results suggest that the polycrystalline {\gamma}-B could be a superhard polycrystalline material for industrial applications.Comment: 16 page

Whole exome sequencing of insulinoma reveals recurrent T372R mutations in YY1

Functional pancreatic neuroendocrine tumours (PNETs) are mainly represented by insulinoma, which secrete insulin independent of glucose and cause hypoglycaemia. The major genetic alterations in sporadic insulinomas are still unknown. Here we identify recurrent somatic T372R mutations in YY1 by whole exome sequencing of 10 sporadic insulinomas. Further screening in 103 additional insulinomas reveals this hotspot mutation in 30% (34/113) of all tumours. T372R mutation alters the expression of YY1 target genes in insulinomas. Clinically, the T372R mutation is associated with the later onset of tumours. Genotyping of YY1, a target of mTOR inhibitors, may contribute to medical treatment of insulinomas. Our findings highlight the importance of YY1 in pancreatic β-cells and may provide therapeutic targets for PNETs

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Effect of variations in Ni-W molar ratio on the microstructure, mechanical properties and tribology of electrodeposited Ni-W/diamond composite coatings

AbstractIn this work, Ni-W/diamond composite alloy coatings were successfully fabricated on low carbon steel by using direct current (DC) electrodeposition.The Ni-W molar ratio was varied in the range of 0.22 to 2 in the plating bath. The effect of variation of Ni-W molar on the microstructure, mechanical properties and tribology of Ni-W/diamond composite coatings was analyzed. The obtained results show that the W content and deposition rate of the Ni-W alloy tends to decrease from 19.02 at. % to 2.1 at. % and 34.86 µm/hr to 11.98 µm/hr, respectively as the Ni-W molar ratio is increased from 0.22 to 2. The hardness results reveal that the highest microhardness of 1346 Hv was reported for the sample fabricated with 0.75 Ni-W molar ratio. Furthermore, the wear rate of the Ni-W/diamond coatings tends to show a significant reduction as the Ni-W molar ratio is increased from 0.22 to 0.75

Effect of diamond particles on the microstructure and composition of pulse plated multilayer Ni-W/diamond composite coatings

The research encompasses the fabrication of multilayer Ni-Wdiamond composite deposits by pulse current electrodeposition. The mean surface diameter of the diamond used for the research was 0.9 microns. The composites were fabricated under various conditions and characterized by means of SEM, EDS and XRD to investigate and analyze their microstructure, grain size and elemental distribution along with variations in morphology under different conditions. The effect of variations in forward and reverse current density along with duty cycle and the combination of various aforesaid conditions on the coatings were studied and analyzed

Effect of Amorphous Boron on the Microstructure and Corrosion Properties of Ni-W Coatings

In this study, a nickel-tungsten/amorphous boron composite coating (Ni-W/B) was successfully deposited on carbon steel using the electrodeposition method. Electrodeposition was performed by dispersing varying quantities of amorphous boron (0, 0.5, 1, and 3 g/L) particles in a Ni-W electrolytic bath. The microstructure and morphology of composite coatings were characterized by scanning electron microscope (SEM). The electrochemical properties of the Ni-W alloy and Ni-W/B composite coatings were studied using electrochemical impedance spectroscopy (EIS), polarization curves, and immersion testing. It was found that the addition of amorphous boron particles to Ni-W coatings can significantly smooth the modified composite coatings and improve the corrosion resistance, probably by changing the corrosion from pitting to uniform corrosion with increasing boron content. The boron concentration of 0.5 g/L in the bath provided the highest corrosion resistance among all the modified coatings

Metal and Metal Oxides for Energy and Electronics

International audienceEnergy is a key world issue in the context of climate change and increasing population, 'calling for alternative fuels, better energy storage, and energy-saving devices. This books reviews the principles and applications of metals and metal oxides for energy, with focus on batteries, electrodes, nanomaterials, electronics, supercapacitors, biofuels and sensors