Repository UNSAP (Universitas Sebelas April)
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Thin Film Devices For 5G Communications
No full textPiezoelectric-based resonators are some of the most used devices in the world. Invisible to most people, they constitute key elements for your mobile phone communications. With the advent of 50, the current technologies for piezoelectric resonators need to leap forward in order to yield the very demanding requirements. Here, we briefly describe the challenges faced by these technologies, as well as what are the different options explored to improve the performance of the devices and thus yield filters that can respond to the phone carriers and phone manufacturer's requests.NEM
Likelihood estimation of the extremal index
No full textA new likelihood method to estimate the extremal index, together with an application to temperature data, is presented. Conditions for the validity of the model are discussed and diagnostics are proposed.STA
Robust ML Auditing using Prior Knowledge
No full textAmong the many technical challenges to enforcing AI regulations, one crucial yet underexplored problem is the risk of audit manipulation. This manipulation occurs when a platform deliberately alters its answers to a regulator to pass an audit without modifying its answers to other users. In this paper, we introduce a novel approach to manipulation-proof auditing by taking into account the auditor's prior knowledge of the task solved by the platform. We first demonstrate that regulators must not rely on public priors (e.g., a public dataset), as platforms could easily fool the auditor in such cases. We then formally establish the conditions under which an auditor can prevent audit manipulations using prior knowledge about the ground truth. Finally, our experiments with two standard datasets illustrate the maximum level of unfairness a platform can hide before being detected as malicious. Our formalization and generalization of manipulation-proof auditing with a prior opens up new research directions for more robust fairness audits.SAC
A satellite- and model-based assessment of the 2003 Russian fires: Impact on the Arctic region
No full textIn this paper, we address the issues of the representation of boreal fires in a global chemistry and transport model (GEOS-Chem) as well as their contribution to the Arctic aerosol optical thickness and black carbon (BC) deposition, with a focus on the 2003 Russian fires. We use satellite observations from the MOPITT, POLDER and MODIS sensors to evaluate the model performances in simulating the fire pollution export over the North Pacific. Our results show that aerosol and carbon monoxide (CO) outflow is best reproduced in our model when fire emissions are increased to 72 Tg for CO, 0.5 Tg C for BC, and 5.3 Tg C for organic carbon over the entire fire season; prescribed on a daily basis; and injected up to 4.5 km in July and August. The use of daily, rather than monthly, biomass burning emission inventories improves significantly the representation of the aerosol outflow, but has little impact on CO. The injection of fire emissions above the boundary layer influences both the CO and aerosol columns but only during the late fire season. The model improvements with respect to the standard configuration induce an increase of a factor up to 2 on the aerosol optical thickness and the mass of BC deposited in the Northern Hemisphere. According to our improved simulation, the 2003 Russian fires contributed to 16–33% of the aerosol optical thickness and to 40–56% of the mass of BC deposited, north of 75°N in spring and summer. They contribute to the aerosol optical thickness by more than 30% during the days of Arctic haze events in spring and summer.LMC
Efficient Charge Extraction out of Nanoscale Schottky Contacts to CdS Nanowires
No full textCharge recombination dynamics in semiconductor nanostructures is of vital importance for photovoltaic or photodetector device applications. We use local photocurrent measurements to explore spatially separated drift- and diffusion-currents close to the edge of gold contacts on top of cadmium sulfide nanowires. By theoretical modeling of the experimental photocurrent profiles, the electron diffusion length and lifetime in the wires are obtained to 0.8 mu m and 1 ns, respectively. In contrast to bulk devices, the nanoscale dimensions of the involved Schottky contacts enable a highly efficient charge carrier extraction from below the electrodes. This finding paves the way for designing nanostructured optoelectronic devices of improved performance.LSE
Metabolic signature in nucleus accumbens for anti-depressant-like effects of acetyl-L-carnitine
No full textEmerging evidence suggests that hierarchical status provide vulnerability to develop stress-induced depression. Energy metabolic changes in the nucleus accumbens (NAc) were recently related to hierarchical status and vulnerability to develop depression-like behavior. Acetyl-L-carnitine (LAC), a mitochondria-boosting supplement, has shown promising antidepressant-like effects opening therapeutic opportunities for restoring energy balance in depressed patients. We investigated the metabolic impact in the NAc of antidepressant LAC treatment in chronically-stressed mice using (1)H-magnetic resonance spectroscopy ((1)H-MRS). High rank, but not low rank, mice, as assessed with the tube test, showed behavioral vulnerability to stress, supporting a higher susceptibility of high social rank mice to develop depressive-like behaviors. High rank mice also showed reduced levels of several energy-related metabolites in the NAc that were counteracted by LAC treatment. Therefore, we reveal a metabolic signature in the NAc for antidepressant-like effects of LAC in vulnerable mice characterized by restoration of stress-induced neuroenergetics alterations and lipid function.LGCCIBMLIFMETPublished under a Creative Commons Attribution (CC-BY) license
Giant Kohn Anomaly and the Phase Transition in Charge Density Wave ZrTe3
No full textA strong Kohn anomaly in ZrTe3 is identified in the mostly transverse acoustic phonon branch along the modulation vector q(P) with polarization along the a(*) direction. This soft mode freezes to zero frequency at the transition temperature T-P, and the temperature dependence of the frequency is strongly affected by fluctuation effects. Diffuse x-ray scattering of the incommensurate superstructure shows a power-law scaling of the intensity and the correlation length that is compatible with an order parameter of dimension n=2.S
Degradation analysis in mixed (MAPbI(3) and MAPbBr(3)) perovskite solar cells under thermal stress
No full textThe current study provides an insight into the thermal stability of perovskite solar cells (PSCs) and the factors causing their degradation. To this end, a systematic stability study was carried out on n-i-p type perovskite solar cells involving mesoporous TiO2 layer. The samples were subjected to varying moisture and thermal conditions under light soaking while being exposed to long-term indoor (5000h) and outdoor (75h) harsh environmental conditions (i.e. 30%-80% RH and 40 degrees C-70 degrees C). To identify performance and morphological changes of PSCs after exposure to thermal stress, advanced characterization techniques including impedance spectroscopy, scanning electron microscopy and glow discharge optical emission spectrometry along with I-V characteristics were used. The un-encapsulated samples exposed to high thermal stress (40-70 degrees C) show degradation in their efficiency more than 40% within the 75h of thermal stress. In contrast, the samples that were kept at room temperature were found to be very stable over 5000h.GM
Un pôle multimodal initiateur du développement urbain, ou comment intégrer les activités dans la ville (Noisy-Le-Sec, F)
No full textNoisy-Le-Sec, région parisienne. Un développement urbain se crée aux limites de la ville, entre un nouveau pôle multimodal et l'axe nord-est d'entrée dans la capitale. Le site est véritablement stratégique pour ce qui est des questions de mobilité à l'échelle du Paris « ville-région » et justifie l'implantation d'une gare, pôle d'échange intermodal entre le train, le RER, le tram, le TGV et le réseau autoroutier. Mais le tissu urbain est déstructuré et hétéroclite : une vaste emprise ferroviaire (maintenance et ferroutage), autrefois implantée en dehors de la ville, se retrouve aujourd'hui en confrontation directe avec celle-ci. L'idée n'est pas de supprimer ou de repousser toujours plus loin tout ce qui n'est pas « propre » pour construire une ville idéale à la place. Dans une logique de développement durable la question serait plus de savoir comment intégrer ces activités, économiquement indispensables, au tissu urbain. Au-delà de ses relations à l'échelle de l'agglomération, la nouvelle gare influence son environnement immédiat, le modifie, lui apporte une nouvelle dynamique de développement. Un développement qui se fait ici principalement sous forme d'activités économiques telles que des entreprises de haute technologie, des ateliers, de l'artisanat. Quelle mixité? Quelle forme? Quelles relations entre activités, logements, et espace public? Ce thème de l'activité peut-il être une réponse aux problèmes périurbains actuels?SAR-DUTACote: 2005.004Archive: MEM.1/1 autre, CD.1/1Groupe de suivi: Berger Patrick (dir. pédagogique); Gilot Christian (prof.); Bonhôte Philippe (maître EPFL); Bonnet Frédéric (expert
Towards the development of a hydrogen battery
No full textA novel Ru-catalyzed hydrogenation of carbon dioxide proceeds with an unprecedented high formic acid to amine ratio (AAR of 2.69), which results in an improved energy content. The presented catalyst system allows for reversible fast hydrogen loading (even at RT) and unprecedented unloading (TON for H2 liberation of 800 000).LCO