Articles científics destacats

This paper focuses on providing an improved and efficient alternative to electromechanical relays (EMRs) in view of the growing demand characteristics for an effective power multiplexing in induction heating applications. A major analytical approach to the design and implementation of bidirectional switches (BDSs) based on different power semiconductor technologies is presented, including thorough static and dynamic characterizations. Emerging gallium nitride high-electron-mobility transistors (GaN HEMTs) and silicon carbide (SiC)-based devices are identified as potential candidates for the mentioned applications.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, vol. 66, no. 3, March 2019, pp. 1832-1841

The viability of using off-chip single-shot imaging techniques for local thermal testing in integrated radio frequency (RF) power amplifiers (PAs) is analyzed. With this approach, the frequency response of the output power and power gain of a Class A RF PA is measured, also deriving information about the intrinsic operation of its transistors. To carry out this paper, the PA is heterodynally driven, and its electrical behavior is down converted into a lower frequency thermal field acquirable with an InfraRed lock-in thermography (IR-LIT) system. After discussing the theory, the feasibility of the proposed approach is demonstrated and assessed with thermal sensors monolithically integrated in the PA. As crucial advantages to RF-testing, this local approach is noninvasive and demands less complex instrumentation than the mainstream commercially available solutions.
IEEE Transactions on Instrumentation and Measurement

Carnitine palmitoyltransferase 1C (CPT1C) is implicated in central regulation of energy homeostasis. Our aim was to investigate whether CPT1C in the ventromedial nucleus of the hypothalamus (VMH) is involved in the activation of brown adipose tissue (BAT) thermogenesis in the early stages of diet-induced obesity.
Molecular Metabolism.

The paper shows that arrays of graphene microtransistors are used to record infraslow cortical brain activity. The devices may be useful for monitoring of brain physiology.
Nature Materials volume 18, pages 280–288 (2019).

The developed microbial sensor based on interdigitated electrode array (3D-IDEA) impedimetric transducer was employed in a biosensing platform especially designed to monitor the bacterial response to the antibiotic ampicillin. To facilitate immobilization of bacteria within the trenches and prevent their deposition on top of the barriers an important novelty is the use of polyIJN-isopropylmethacrylamide) p(NIPMAM) microgels working as antifouling agents, deposited on top of the barriers by microcontact printing.
Lab. Chip, 2019, vol.19. pp. 1436 – 1447.

TiN/Ti/HfO2/W memristors have been investigated to mimic the spike-time dependent plasticity (STDP) of biological synapses at multiple time scales. For this purpose, a smart software tool has been implemented to control the instrumentation and to perform a dedicated ultra-fast pulsed characterization. Different time scales, from tens of milliseconds to hundreds of nanoseconds, have been explored to emulate the STDP learning rule in electronic synapses. The impact of such times on the synaptic weight potentiation and depression characteristics has also been discussed.
Microelectronic Engineering 215 (2019) 111014.

Modular microfluidic systems based on a new magnetic clamping approach, which enables both interconnection of microfluidic modules and reversible integration of solid-state sensors, is presented in this work. The system layout allows the easy assessment of the system fluidic performance by using optically transparent and low cost polymeric materials.
ACS Omega, 2019, 4 (4), pp 6192–6198.

Implantable electrodes act with direct electrical contact although recent work has shown that electrostimulation is also possible through non-contact wireless settings, through the generation of dipoles at the borders of the material by bipolar electrochemistry. Finite element studies shown here with the same configuration that the experimental processes described, evidence voltage profiles in qualitative agreement with known bipolar effects, although with a clear difference between intercalation materials and metals. These observations may explain the differences in neural cell growth observed for various substrate material.
Electrochimica Acta

Growth monitoring during the early stages of vapor deposition is of prime importance to understand the growth process, the microstructure, and thus the overall layer properties. We demonstrate that phonons can be used as an extremely sensitive probe to monitor the real-time evolution of film microstructure during growth. For that purpose, a silicon nitride membrane-based sensor is fabricated to measure the in-plane thermal conductivity of thin film samples. Operating with the 3ω-Völklein method at low frequencies, the sensor shows an exceptional resolution down to Δ(κ⋅t)=0.065W/mKnm, enabling accurate measurements even in poor conductive samples.
Phys. Rev. Applied 12, 014007

This paper presents an in-deep review of the state of the art concerning power modules, identifying the electrical requirements for the modules and the power conversion topologies that will best suit future HEV/EV drives. Current wide band-gap (WBG) technologies such as SiC and GaN, are reviewed and, after a market analysis, the most suitable power semiconductor devices are highlighted. Among them, it can be concluded that JBS diodes and MOSFETs are the most adequate for this application, because they can substitute traditional Si FRD diodes and Si IGBTs, providing lower power losses and higher operation temperatures. The migration from Si IGBTs to the aforementioned technologies would be simpler than expected, as the same firing circuitry (with minor modifications) can be reused. The paper, also focuses on practical design aspects of the module, such as optimum WBG die parallelization, placement and ceramic substrate routing. This work has been developed in a collaboration between the Teknologia Elektronikoa Saila - Bilboko Ingenieritza Goi Eskola Teknikoa - UPV/EHU and the Power Devices and Systems Group from IMB-CNM(CSIC).
Renewable and Sustainable Energy Reviews, vol. 113, October 2019