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Scanning tunneling spectroscopy suggests the formation of a two dimensional electron gas (2DEG) on the TiO2 terminated surface of undoped SrTiO3 single crystals annealed at temperature lower than 400 {\deg}C in ultra high vacuum conditions. Low energy electron diffraction indicates that the 2D metallic SrTiO3 surface is not structurally reconstructed, suggesting that non-ordered oxygen vacancies created in the annealing process introduce carriers leading to an electronic reconstruction. The experimental results are interpreted in a frame of competition between oxygen diffusion from the bulk to the surface and oxygen loss from the surface itself., Comment: 9 pages, 3 figures, submitted to Physical Review B

Uroflowmetry (UF) is a crucial guideline-recommended tool for men with benign prostatic obstruction (BPO). Moreover, UF is a helpful decision-making tool for the management of patients with lower urinary tract symptoms (LUTS) and benign prostatic hyperplasia (BPH). In the last few years, telemedicine and telehealth have increased exponentially as cost-effective treatment options for both patients and physicians. Telemedicine and telehealth have been well positioned during the COVID-19 pandemic to prevent healthcare system overload and to ensure adequate management of patients through screening, diagnosis, and follow-up at home. In the present manuscript, the main characteristics and performance of a novel and low-cost device for home-based UF have been analyzed. The simple weight-transducer method has been applied to perform UF. An inexpensive load cell connected to a 24 bit analogic digital converter (ADC) sends data to a cloud server via SIM card or home Wi-Fi. Data are processed and shown in graphics with both volume and flow rate as a function of time, allowing for measurement of average flow rate, maximum flow rate, voided volume, and voiding time. A numerical algorithm allows for filtering of the dynamic effect due to the urine gravity acceleration and for removing the funnel to simplify the home measurement procedure. Through an online platform, the physician can see and compare each UF data. The device’s reliability has been validated in a first laboratory setting and showed excellent performance. This approach based on domiciliary tests and an online platform can revolutionize the urologic clinic landscape by offering a constant patient cost-effective follow-up, eliminating the time wasted waiting in the office setting.

We revisit the classical rigid-fluxon model which describes the effect of an applied magnetic flux on the RF surface resistance of a superconductor and discuss explicit formulations for a few limit cases. As an application, we discuss the role of magnetic flux on the enhanced surface resistance of RF accelerating cavities based on niobium, depending on its material properties. We also assess the conditions for the use of high-temperature superconductors for carrying the beam image RF currents in future high-energy circular hadron colliders such as the future circular collider being studied at CERN.

Core-cyanated perylene diimide (PDI_CY) derivatives are molecular compounds exhibiting an uncommon combination of appealing properties, including remarkable oxidative stability, high electron affinities, and excellent self-assembling properties. Such features made these compounds the subject of study for several research groups aimed at developing electron-transporting (n-type) devices with superior charge transport performances. After about fifteen years since the first report, field-effect transistors based on PDI_CY thin films are still intensely investigated by the scientific community for the attainment of n-type devices that are able to balance the performances of the best p-type ones. In this review, we summarize the main results achieved by our group in the fabrication and characterization of transistors based on PDI8-CN2 and PDIF-CN2 molecules, undoubtedly the most renowned compounds of the PDI_CY family. Our attention was mainly focused on the electrical properties, both at the micro and nanoscale, of PDI8-CN2 and PDIF-CN2 films deposited using different evaporation techniques. Specific topics, such as the contact resistance phenomenon, the bias stress effect, and the operation in liquid environment, have been also analyzed.

We present a systematic study of the superconducting properties of high quality V3Si thin films, grown by high vacuum pulsed laser deposition from a stoichiometric target, a technique never reported in literature for this compound. By changing both the substrate (crystal structure and orientation) and the deposition conditions (substrate temperature, target-substrate distance, laser frequency and pulse energy) the critical temperature and the resistivity values of the samples have been finely tuned. Best results (TC = 16.1 K and Residual Resistivity Ratio RRR = 8.5) are obtained for deposition temperatures higher than 1200degC on both LaAlO3 and MgO substrates. All the samples are polycrystalline, that however does not affect the good quality of the transport properties. The possibility of multiband superconductivity in this compound is investigated, probing as a function of temperature: (i) the critical field up to 28 T using voltamperometric measurements, and (ii) the superfluid density via magnetic penetration depth measurements with a single coil inductive technique operating in the MHz region.

Single crystals of the novel superconductor beta ''-(BEDT-TTF)(4)[(H3O)Fe(C2O4)(3)]center dot C6H5Br charge-transfer salt were studied using a scanning tunnelling microscope. The measured samples have an onset critical temperature of about 4.0 K. Features often reported on similar compounds were observed in the tunnelling spectra at 1.4 K. STS spectra are compared with several models for the superconducting density of states. Our analysis evidences inhomogeneous superconductivity and indicates that the presence of a magnetic layer into the sample plays a role in determining the superconducting spectroscopic features. (C) 2008 Elsevier Masson SAS. All rights reserved.

The 'Q-slope' problem has so far strongly limited the application of niobium thin film sputtered copper cavities in high field accelerators. In the present paper, based on experimental evidence, we consider the hypothesis that the Q-slope is related to enhanced thermal boundary resistance R Nb/Cu at the Nb/Cu interface, due to poor thermal contact between film and substrate. We have developed a simple model that directly connects the Q versus E acc curves to the distribution function f(R Nb/Cu) of R Nb/Cu values at the Nb/Cu interface over the cavity surface. Starting from different Q versus E acc experimental curves from different sources, using typical 'inverse problem' methods, we deduce the corresponding distribution functions generating those curves. The results show, for all the examined cases, very similar functional dependences of f(R Nb/Cu) and prove that, to describe the experimental Q versus E acc curves, it is sufficient to assume that only a small fraction of the film over the cavity surface is in poor thermal contact with the substrate. The whole body of information and data reported seems to indicate that the main origin of the Q-slope in thin film cavities is related to bad adhesion at the Nb/Cu interface. Strategies to solve the Q-slope problem improving the film adhesion are finally delineated.

The empirical and theoretical justification of Gartner hype curves is a very relevant open question in the field of Technological Life Cycle analysis. The scope of the present paper is to introduce a simple model describing the growth of scientific/technological research impact, in the specific case where science is the main source of a new idea driving a technological development, leading to hype-type evolution curves. The main idea of the model is that, in a first stage, the growth of the scientific interest of a new specific field (as can be measured by publication numbers) basically follows the classical logistic growth curve. At a second stage, starting at a later trigger time, the technological development based on that scientific idea (as can be measured by patent deposits) can be described as the integral (in a mathematical sense) of the first curve, since technology is based on the overall accumulated scientific knowledge. The model is tested through a bibliometric analysis of the publication and patent deposit rate for Organic Light Emitting Diodes (OLED) scientific research and technology, as well as for other emerging technologies., 8 pages, 2 figures

Aladin2 is an experiment devoted to the first measurement of variations of Casimir energy in a rigid cavity. The main scientific motivation relies on the possibility of the first demonstration of a phase transition influenced by vacuum fluctuations. The guiding principle of the measurement, based on the behaviour of the critical field for an in-cavity superconducting film, will be only briefly recalled. In this paper, after an introduction to the long term motivations, the experimental apparatus and the results of the first measurement of sensitivity will be presented in detail, particularly in comparison with the expected signal. Last, the most important steps towards the final measurement will be discussed., Comment: Talk given by Calloni at QFEXT05 Conference in Barcelona: Quantum Field Theory Under the Influence of External Conditions

Films of self-assembled (CnH2n+1NH3)2CuCl4 (1 ≤ n ≤ 4) hybrid structures were prepared and characterized with respect to the structure, the optical absorption and the transport properties. The films were deposited in-situ, by the Single Source Thermal Ablation (SSTA) procedure on glassy, crystalline and polymeric substrates. The film structure and the morphology, thickness and roughness were almost independent on the substrate. X-ray diffraction analysis showed that the films are well crystallized and c-axis oriented. Optical absorption measurements in the 9000-52000 cm–1 interval confirmed the good quality of the films. They also proved that the absorption phenomena are mainly related to the inorganic CuCl64– clusters and to their geometrical configuration. Due to the high optical quality of the films novel absorption features were revealed. The electrical transport measurements indicated that the films are insulating at 300 K, with resistivity values ranging between 103 and 104 Ωcm. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

In this paper we will describe the main results of the activity aimed to develop a prototype of superconducting receiver front-end (HTS RFE) for specific application in UMTS network. The system has been specifically designed to reach very low noise figure on the receiving channel to exploit the best performance in terms of sensitivity of the up-link channel.

In this paper the performances of superconducting devices based on fractal layout are discussed. Depending on their shape, fractals are characterized by self-similarity and/or space-filling properties. The former allows the design of superconducting filters with highly reduced dimensions and no appreciable loss of performance, whereas the latter is the basis for the fabrication of multi-band antennas which hold promise for very interesting applications. Our attention was focused on the square Koch loop and the Sierpinski gasket geometries. In particular, prototype four pole filters for UMTS (Universal Mobile Telecommunications Systems) applications based on Koch resonators have been designed. Measurements performed on prototype devices fabricated by using double-sided superconducting thin films are reported and compared with simulations.

In this paper, the design principles of a new miniaturized superconducting planar filter configuration is presented. The configuration is based on the combined use of dual-mode cross-slotted patch resonators and stepped resonators. Four-pole filters exhibiting a quasi-elliptical response and with operating frequencies in K-, L-, and C-bands have been designed as a test vehicle of the new configuration. The analyzed topology exhibits a high degree of miniaturization, requiring less than 50% of the area occupied by filters based on dual-mode or hairpin resonators. The physical origin of the transmission zeros is discussed, deriving equivalent-circuit descriptions that are capable of reproducing the measured frequency response. In order to confirm the validity of the introduced design principles, experimental performances on an exemplary L-band filter, realized using a YBCO film deposited on an MgO substrate and exhibiting a 3% fractional bandwidth, are presented. The measured frequency response obtained at T = 77 K agrees well with the simulations, presenting an insertion loss of 0.1 dB and a power handling of 34 dBm.