Formation of endohedral Ni@C60 and exohedral Ni-C60 metallofullerene complexes by simulated ion implantation

The interaction of thermal and hyperthermal Ni ions with gas-phase C₆₀ fullerene was investigated at two temperatures with classical molecular dynamics simulations using a recently developed interatomic many-body potential. The interaction between Ni and C₆₀ is characterized in terms of the Ni-C₆₀ binding sites, complex formation, and the collision and temperature induced deformation of the C₆₀ cage structure. The simulations show how ion implantation theoretically allows the synthesis of both endohedral Ni@C₆₀ and exohedral Ni-C₆₀ metallofullerene complexes.     

Silicon-on-Insulator CWDM Power Monitor/Receiver With Integrated Thin-Film InGaAs Photodetectors

In this letter, we demonstrate a compact and cost-effective four-channel demultiplexer with integrated photodetectors for application in coarse wavelength-division-multiplexing systems. The device consists of a silicon-on-insulator planar concave grating (PCG) demultiplexer and heterogeneously integrated InAlAs-InGaAs metal-semiconductor-metal photodetectors, and has a footprint of only 0.1 mm² . The PCG and integrated photodetectors have a responsivity of 0.6 A/W for TE-polarized light. The integrated device has an optical crosstalk of -25 dB.     

Chloride pitting and water chemistry control in cooling or boiler circuits

The effect of different anions (bicarbonate, phosphate, sulphate, hydroxyl) on the pitting corrosion by chloride ions has been investigated for a number of ferritic or austenitic steels and nickel alloys at different temperatures up to 175°C. For most of the alloys the normal order of inhibition is PO₄³ > SO₄^2- HCO₃, but some anomalies have been encountered for stainless steels at lower temperatures (<100°C), where the inhibitive action of SO₄^2- maybe more pronounced that the inhibition which can be obtained by adding equal amounts of phosphate. In the absence of strongly passivating alloying elements, such as chromium, high SO₄² concentrations may have a deteriorative effect. The same result may also be found under cathodic polarization conditions, where SO₄^2- and HCO₃ seem to stimulate reductive dissolution of the protective surface layer and may even cause some kind of pitting-type attack.     

Software sensors for bioprocesses

State estimation is a significant problem in biotechnological processes, due to the general lack of hardware sensor measurements of the variables describing the process dynamics. The objective of this paper is to review a number of software sensor design methods, including extended Kalman filters, receding-horizon observers, asymptotic observers, and hybrid observers, which can be efficiently applied to bioprocesses. These several methods are illustrated with simulation and real-life case studies.     

Plasma-driven CO2 hydrogenation to CH3OH over Fe2O3/γ-Al2O3 catalyst

We report a plasma-assisted CO₂ hydrogenation to CH₃OH over Fe₂O₃/γ-Al₂O₃ catalysts, achieving 12% CO₂ conversion and 58% CH₃OH selectivity at a temperature of nearly 80°C atm pressure. We investigated the effect of various supports and loadings of the Fe-based catalysts, as well as optimized reaction conditions. We characterized catalysts by X-ray powder diffraction (XRD), hydrogen temperature programmed reduction (H₂-TPR), CO₂ and CO temperature programmed desorption (CO₂/CO-TPD), high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), x-ray photoelectron spectroscopy (XPS), Mössbauer, and Fourier transform infrared ( FTIR). The XPS results show that the enhanced CO₂ conversion and CH₃OH selectivity are attributed to the chemisorbed oxygen species on Fe₂O₃/γ-Al₂O₃. Furthermore, the diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) and TPD results illustrate that the catalysts with stronger CO₂ adsorption capacity exhibit a higher reaction performance. In situ DRIFTS gain insight into the specific reaction pathways in the CO₂/H₂ plasma. This study reveals the role of chemisorbed oxygen species as a key intermediate, and inspires to design highly efficient catalysts and expand the catalytic systems for CO₂ hydrogenation to CH₃OH.     

Towards foundry approach for silicon photonics: silicon photonics platform ePIXfab

Fabless access to wafer-scale silicon photonics technology is moving silicon photonics closer to becoming a mainstream technology and opens up new exciting areas for research at the same time. It is only by using wafer-scale technology that this emerging field will be able to realise its promise: to become a disruptive technology. At the basis of the rationale for silicon photonics is a complex of photonic functions integrated on a single chip, coupled to a stable, high-yield volume fabrication technology base. ePIXfab is a service platform offering R oriented access to state-of-the-art 200 mm wafer-scale CMOS technology optimised for silicon photonics purposes.     

Compact Focusing Grating Couplers for Silicon-on-Insulator Integrated Circuits

We report experimental results on compact and broadband focusing grating couplers, both in silicon-on-insulator (SOI) and gold on SOI. An eight-fold length reduction of the coupling structure from fiber to photonic wire in SOI, as compared to a linear grating and adiabatic taper, is obtained, without performance penalty. A proof of principle is given for a focusing grating coupler in gold on SOI, with 20% fiber-to-focus efficiency.