Electrical modeling of packaging discontinuities: A general methodology based on the three-dimensional TLM concept

A general methodology for modeling packages using the three-dimensional (3D) TLM method is presented. S parameters are calculated from reflected and transmitted signals, and electrical parameters of equivalent networks are extracted. Frequency domain results (up to 30 GHz) are presented for a microstrip right-angle bend, a cross junction, and vias. The purpose of this article is to demonstrate the possibilities of using the 3D TLM method for electrical modeling in packaging applications.     

Advanced Multimaterial Electronic and Optoelectronic Fibers and Textiles

The ability to integrate complex electronic and optoelectronic functionalities within soft and thin fibers is one of today's key advanced manufacturing challenges. Multifunctional and connected fiber devices will be at the heart of the development of smart textiles and wearable devices. These devices also offer novel opportunities for surgical probes and tools, robotics and prostheses, communication systems, and portable energy harvesters. Among the various fiber‐processing methods, the preform‐to‐fiber thermal drawing technique is a very promising process that is used to fabricate multimaterial fibers with complex architectures at micro‐ and nanoscale feature sizes. Recently, a series of scientific and technological breakthroughs have significantly advanced the field of multimaterial fibers, allowing a wider range of functionalities, better performance, and novel applications. Here, these breakthroughs, in the fundamental understanding of the fluid dynamics, rheology, and tailoring of materials microstructures at play in the thermal drawing process, are presented and critically discussed. The impact of these advances on the research landscape in this field and how they offer significant new opportunities for this rapidly growing scientific and technological platform are also discussed.     

Effect of microstructure of simulated heat‐affected zone on low‐ to high‐cycle fatigue properties of low‐carbon steels

To clarify the effect of microstructural changes on the fatigue property of the weld heat‐affected zone (HAZ), low‐ to high‐cycle fatigue tests were conducted on 16 types of simulated HAZ specimens that had been prepared using thermal processes. The results showed the fatigue S‐N curves of the HAZ to be widely scattered as a function of strength level. These fatigue data were divided into two groups: coarse grain (CG) and fine grain (FG) HAZ, when strain amplitude was used to represent S‐N curves. The fatigue data for the CGHAZ group showed a relatively short fatigue life. Based on surface observations, the initiated fatigue crack size of CGHAZ was larger than that of FGHAZ as a function of microstructural unit size. Hence, fatigue crack growth life, which is almost the same as total fatigue life of CGHAZ, decreased.     

Efficient direct electron transfer of PQQ-glucose dehydrogenase on carbon cryogel electrodes at neutral pH

We present a comprehensive study of the direct electron transfer reaction of soluble PQQ-GDH from Acinetobacter calcoaceticus. Wild-type PQQ-sGDH nonspecifically adsorbed on carbon cryogel electrodes retained its enzymatic activity for glucose and maltose oxidation at pH 7.2 and 37 °C. The cyclic voltammograms in the absence of enzymatic substrate showed 2 redox peaks that suggest a two-step, one-electron oxidation/reduction of PQQ. Calibration curves showed a linear amperometric response for a wide glucose concentration range, including the values normally found in blood. At saturation, the catalytic current reached 0.93 mA cm(-2). Altogether the experimental results suggest that the amperometric output of the electrodes and the shape of the calibration curves represent a combination of the intrinsic enzyme kinetics, the maximum rate of heterogeneous electron transfer and the substrate accessibility to the enzyme's active center caused by the confinement of the enzyme into the mesoporous structure. A new mutant enzyme, N428C, developed in our group that shows almost twice the maximum catalytic activity in homogeneous experiments in solution, also showed a DET signal on carbon cryogel electrodes for glucose electro-oxidation. The higher activity for the mutant enzyme was also verified on the electrode surface.     

Is it possible to check microcomponent coatings?

Optical microcomponents are increasingly used in laser optical systems because of their many and novel industrial applications. These components are coated in order to enhance their optical performance, but optical characterizations are very difficult due to the shapes and small size. Thus, to perform this kind of measurement, special devices are needed. It is difficult to check component optical responses after manufacturing. Thus a new method, developed by the French Atomic Energy and Alternative Energies Commission, is proposed to fill this gap.     

New bioinspired membrane made of a biological ion channel confined into the cylindrical nanopore of a solid-state polymer

A hybrid nanoporous membrane made of a solid-state polymeric thin film in which an ion channel is confined is realized. The primary and extremely encouraging results obtained by confocal fluorescence spectroscopy and ion diffusion measurement demonstrate respectively that (i) the considered ion channel, that is, Gramicidin-A, can be confined selectively inside the nanopores and (ii) the ionic permeability of the membrane is enhanced. Atomistic molecular simulations are also reported and fruitfully compared to the experimental findings.     

Propellants Reactivity Enhancement with Nanothermites

Propellant grains (Vectan A1) were coated with a thin and stable layer (50 μm, 10 wt‐%) of a “green” sulfate‐based nanothermite (Na₂SO₄/Al). This flash composition was used herein as an internal pyrotechnic lighter to accelerate the ignition and the combustion of the propellant. The combustion of the modified propellant, which was tested in one‐end open tubes, propagates four orders of magnitude faster than the one of pristine Vectan A1. This tremendous effect was tuned by varying the proportion of coated Vectan A1 grains from 20 to 100 % in the samples. The percolation threshold is in between 20 and 40 %. Beyond this point, the effect can be improved by increasing the proportion of nanothermite‐coated propellant grains in the charge.     

Manganese‐Catalyzed and Promoted Reactions of H‐Phosphinate Esters

H‐Phosphinates react with alkenes and alkynes using catalytic manganese(II) acetate. Under stoichiometric conditions with manganese(III) acetate or with catalytic manganese(II) acetate+excess manganese(II) oxide various reactions like arylation or cyclization through radical oxidative arylation can take place. Whereas the chemistry of manganese is already well developed for the functionalization of H‐phosphonates, the present methodology provides an unprecedented access to functionalized phosphinates in acceptable to good yields.