Search results for "Note"

Selective Encapsulation and Enhancement of the Emission Properties of a Luminescent Cu(I) Complex in Mesoporous Silica

2018

Influence Of The Electrical Parameters On The Fabrication Of Copper Nanowires Into Anodic Alumina Templates

2009

Abstract Metallic copper nanowires have been grown into the pores of alumina membranes by electrodeposition from an aqueous solution containing CuSO 4 . and H 3 BO 3 at pH 3. In order to study the influence of the electrical parameters on growth and structure of nanowires, different deposition potentials (both in the region where hydrogen evolution reaction is allowed or not) and voltage perturbation modes (constant potential or unipolar pulsed depositions) were applied. In all cases, pure polycrystalline Cu nanowires were fabricated into template pores, having lengths increasing with the total deposition time. These nanowires were self-standing, because they retain their vertical orientati…

Sintering of copper nanopowders under hydrogen: an in situ X-ray diffraction analysis.

2003

Abstract The reduction by hydrogen gas of the cuprite layer on copper nanocrystals and the subsequent sintering of the nano-particles were studied using in-situ X-ray diffraction and dilatometry. Spherical nanocrystals produced by evaporation and condensation have an average size of 35 nm, exhibiting a large surface curvature. Each nanoparticle is coated with a 3.5 nm layer of Cu 2 O, which is rough and disordered, as revealed by high-resolution electron microscopy. Reduction by hydrogen of this curved cuprite layer occurs at 363 K, which is ≈65 K lower than is observed on a layer supported by micrometer-sized or bulk copper with a flat surface. The reduction process and its effect on the s…

Effect of current on the sintering of pre-oxidized copper powders by SPS

2017

Abstract As mentioned in the literature, SPS (Spark Plasma Sintering) technology combines uniaxial charge and pulsed currents to achieve the rapid sintering of powders. Although the utilization of current is often reported, an understanding of its role in the sintering mechanisms is still a subject of controversy. In fact, the oxide layer around metal particles is sometimes considered to be a dielectric gap in which discharges may occur: these discharges can clean the surface of particles and enhance densification. In this paper, an oxide layer was grown on the particle surface of a copper powder, and the growth enabled the study of the role of current on such dielectric layers. The powders…

Segregation of copper oxide on calcium copper titanate surface induced by Graphene Oxide for Water splitting applications

2020

Abstract Photoelectrochemical cells (PEC) are promising devices for hydrogen production via sunlight energy. One of the important challenges in this area is to design photoactive electrodes able to absorb visible light. A good photoelectrochemical behavior depends on the presence of surface active sites to photogenerate current at the lower possible potential for water splitting. Recent investigations in this field are focusing on perovskite materials such as CaCu3Ti4O12 (CCTO) as visible light active electrode due its outstanding structure in which CCTO encloses in its structure a visible light absorbance component (CuO). The presence CuO on the material surface is mainly responsible for t…

Template electrosynthesis of aligned Cu2O nanowires

2008

Abstract Large arrays of aligned copper oxide nanowires were produced by electrodeposition, using anodic alumina membranes as template. We have studied the effect of two fundamental parameters involved in fabrication process: potential perturbation and bath composition. Performing electrodeposition from a copper acetate/sodium acetate bath (pH 6.5), we found that chemical composition of nanowires varied in dependence on the shape of the applied potential perturbation: pure copper oxide nanowires were produced by pulsed potential, whilst continuous electrodeposition resulted in a co-deposition of Cu and Cu 2 O. In a copper lactate bath, buffered at pH 10, the shape of perturbation did not in…

Grafting and characterization of dodecylphosphonic acid on copper: Macro-tribological behavior and surface properties

2013

International audience; Thin film of n-dodecylphosphonic acid (DDPA) was prepared on a copper oxide substrate via a molecular self-assembly process. The composition, structure, organization, surface energy, morphology, and electrochemical behavior of the DDPA filmwere characterized bymeans of X-ray photoelectron spectroscopic analysis (XPS), polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), contact angle measurement v(CAM), microscopic observations, and electrochemistry. The friction behavior of the DDPA film adsorbed on copper oxide substrate sliding against a Si3N4 ball was examined on a linear reciprocating tribological tester. Worn surfaces of the DDPA film…

Influence of Pressure and Temperature on X-Ray Induced Photoreduction of Nanocrystalline CuO

2018

The authors are grateful to Prof. Alain Polian for providing NDAC cell. Parts of the present research have been carried out at the ODE beamline at SOLEIL.

Reliable Propagation of Magnetic Domain Walls in Cross Structures for Advanced Multiturn Sensors

2017

[EN] We develop and analyze an advanced concept for a domain-wall-based sensing of rotations. Moving domain walls in n closed loops with n - 1 intersecting convolutions by rotating fields, we are able to sense n rotations. By combining loops with coprime numbers of rotations, we create a sensor system allowing for the total counting of millions of turns of a rotating applied magnetic field. We analyze the operation of the sensor and identify the intersecting cross structures as the critical component for reliable operation. Specifically, depending on the orientation of the applied field angle with the magnetization in the branches of the cross, a domain wall is found to propagate in an unwa…

Co-creation with Companies: A Means to Enhance Societal Impact of University Researchers?

2019

AbstractIn this chapter, we explore co-creation as a form of societal interaction of science. We approach co-creation as a goal-oriented form of dynamic interaction aiming at mutual benefit of all parties. As such, we exclude technology transfer and other linear societal interaction forms that follow a closed-model innovation format. We argue that focusing solely on tapping the needs of researchers and ‘pure’ science would lead to ignoring the broader context in which researchers work. An excessive focus on meeting the needs of external stakeholders could jeopardize the preconditions of science. Hence, this chapter explores how researcher-company co-creation can be nurtured in a heavily ins…