669 research outputs found
Miniaturised wearable UHF-RFID tag with tuning capability
By carving a 'square-smile'slot profile over a folded patch, a miniaturised UHF-RFID tag is
obtained, having a convenient two-step tuning mechanism (coarse and fine). This is useful
to adapt the same tag to European and US frequencies and to make on-site corrections. The
antenna is half the size of a credit card and can be read up to 5m when attached onto the
body. The flexible and lightweight EPDM foam substrate makes the tag suited to be
integrated in badges, wallets, pockets, plasters, wristbands and various garments
Kinetic Inductance Detectors for the OLIMPO experiment: design and pre-flight characterization
We designed, fabricated, and characterized four arrays of horn--coupled,
lumped element kinetic inductance detectors (LEKIDs), optimized to work in the
spectral bands of the balloon-borne OLIMPO experiment. OLIMPO is a 2.6 m
aperture telescope, aimed at spectroscopic measurements of the
Sunyaev-Zel'dovich (SZ) effect. OLIMPO will also validate the LEKID technology
in a representative space environment. The corrected focal plane is filled with
diffraction limited horn-coupled KID arrays, with 19, 37, 23, 41 active pixels
respectively at 150, 250, 350, and 460GHz. Here we report on the full
electrical and optical characterization performed on these detector arrays
before the flight. In a dark laboratory cryostat, we measured the resonator
electrical parameters, such as the quality factors and the electrical
responsivities, at a base temperature of 300mK. The measured average
resonator s are 1.7, 7.0, 1.0, and
1.0 for the 150, 250, 350, and 460GHz arrays, respectively.
The average electrical phase responsivities on resonance are 1.4rad/pW,
1.5rad/pW, 2.1rad/pW, and 2.1rad/pW; the electrical noise
equivalent powers are 45, 160,
80, and 140, at 12 Hz. In the OLIMPO
cryostat, we measured the optical properties, such as the noise equivalent
temperatures (NET) and the spectral responses. The measured NETs are
, , ,
and , at 12 Hz; under 78, 88, 92, and 90 mK
Rayleigh-Jeans blackbody load changes respectively for the 150, 250, 350, and
460 GHz arrays. The spectral responses were characterized with the OLIMPO
differential Fourier transform spectrometer (DFTS) up to THz frequencies, with
a resolution of 1.8 GHz.Comment: Published on JCA
Synthesis and Structures of Two Triorganotin(IV) Polymers R3Sn{O2CC6H4[N=C(H)}{C(CH3)CH(CH3)-3-OH]-p}n (R = Me and Ph) Containing a 4-[(2Z)-(3-Hydroxy-1-methyl-2-butenylidene)amino] benzoic Acid Framework
Two new polymeric triorganotin(IV) complexes R3Sn{O2CC6H4[N=C(H)}{C(CH3)CH(CH3)-3-OH]-p}n ([Me3Sn(LH)]n: 1) and([Ph3Sn(LH)]n: 2) containing a 4-[(2Z)-(3-hydroxy-1-methyl-2-butenylidene)amino]benzoate (LH) framework were prepared.Both compounds have been characterized by 1H, 13C, 119Sn NMR, IR and 119Sn Mossbauer spectroscopic techniques in combination with elemental analyses. The crystal structures of complexes 1 and 2 reveal that they exist as polymeric zig-zag chains in which the LH-bridged Sn-atoms adopt a trans-R3SnO2 trigonal bipyramidal configuration with R groups in the equatorial positions and the axial sites occupied by an oxygen atom from the carboxylate ligand and the alcoholic oxygen atom of the next carboxylate ligand in the chain. The carboxylate
ligands coordinate in the zwitterionic form with the alcoholic proton moved to the nearby nitrogen atom
Diseño de una guÃa de prácticas de laboratorio de acuerdo con las orientaciones del EEES
La adaptación de la docencia universitaria al Espacio Europeo de Educación Superior (EEES) supone un cambio en los sistemas de enseñanza actual. En este sentido el desarrollo de guÃas de laboratorio capaces de informar al alumnado, y normalizar la confección y presentación de las prácticas de laboratorio, asegurando una mejor calidad de la docencia y coordinación entre grupos, viene a cumplir con algunos de los objetivos pretendidos en el contexto de la Convergencia Europea. La GuÃa que se presenta, destinada a su empleo en la docencia práctica de una asignatura troncal de la licenciatura en Farmacia en la Universidad de Granada, recoge las indicaciones necesarias para llevar a cabo un trabajo seguro y eficiente en los laboratorios
Raman scattering reveals strong LO-phonon-hole-plasmon coupling in nominally undoped GaAsBi: optical determination of carrier concentration
We report room-temperature Raman scattering studies of nominally undoped (100) GaAs1−xBix epitaxial layers exhibiting Biinduced (p-type) longitudinal-optical-plasmon coupled (LOPC) modes for 0.018≤x≤0.048. Redshifts in the GaAs-like optical modes due to alloying are evaluated and are paralleled by strong damping of the LOPC. The relative integrated Raman intensities of LO(Γ) and LOPC ALO/ALOPC are characteristic of heavily doped p-GaAs, with a remarkable near total screening of the LO(Γ) phonon (ALO/ALOPC →0) for larger Bi concentrations. A method of spectral analysis is set out which yields estimates of hole concentrations in excess of 5 × 1017 cm−3 and correlates with the Bi molar fraction. These findings are in general agreement with recent electrical transport measurements performed on the alloy, and while the absolute size of the hole concentrations differ, likely origins for the discrepancy are discussed. We conclude that the damped LO-phonon-hole-plasmon coupling phenomena plays a dominant role in Raman scattering from unpassivated nominally undoped GaAsBi
A New Quantitative Classification of the Extrahepatic Biliary Tract Related to Cystic Duct Implantation
Background: Knowledge regarding biliary anatomy and its variations, including the cystic duct (CD), is important in the pre-surgical setting and for predicting biliary diseases. However, no large series has focused on CD evaluation using a quantitative analysis. The primary aim of this prospective study was to create a ‘taxonomic’ classification of CD anatomy in a large cohort of subjects who underwent magnetic resonance cholangiopancreatography (MRCP). The secondary aim was to evaluate the correlations between extrahepatic bile duct (EHBD) variants and biliary diseases. Methods: We enrolled patients who underwent MRCP for different clinical indications from January 2017 to May 2019. Demographical, anatomical and clinical data were evaluated using statistical analyses, as appropriate. The anatomical assessment of EHBD was performed using the standard classification for CD in low, medium, and high insertions, and the lengths of CD to the duodenal papilla (DP), and EHBD was determined to conduct a new quantitative analysis. Results: The final study population comprised 1004 subjects. A new classification for EHBD as per the percentile distribution of the ratio CDDP/EHBD was designed, and the following categories were obtained: type 1 (below the 25th percentile) for CDDP/EHBD ratio ≤ 50%; type 2 (25th to 75th percentile) for CDDP/EHBD ratio 51–75% and type 3 (above the 75th percentiles) for CDDP/EHBD ratio > 75%. Type 1 of the new classification of CD implantation was significantly superior in terms of the detection of low, medial and intra-pancreatic CD that was significantly correlated with a high risk of choledochal lithiasis in comparison with the standard classification (P < 0.001). Conclusions: The new classification of CD implantation enables identification of the vast majority of intra-pancreatic CDs that are correlated with a high risk of choledochal lithiasis in a single category (type 1) that is easy to identify using imaging
Imaging of colorectal liver metastases: New developments and pending issues
Computed tomography (CT), magnetic resonance imaging (MRI), and 18-fluorideoxyglucose positron emission tomography (18 FDG-PET) are historically the most accurate imaging techniques for diagnosing liver metastases. Recently, the combination of diffusion-weighted imaging and hepatospecific contrast media, such as gadoxetic acid in MRI, have been demonstrated to have the highest diagnostic accuracy, sensitivity, and specificity for detecting liver metastases. Various recent meta-analyses have confirmed the diagnostic superiority of this combination (diffusion-weighted imaging and gadoxetic acid-enhanced MRI), especially in terms of per lesion sensitivity, as compared with CT and18 FDG-PET, even for smaller lesions ( 641 cm). However, none of the oncological guidelines have suggested the use of MRI as a first-line technique for liver metastasis detection during the staging process of oncological patients. This review analyzes the history of the principal imaging techniques for the diagnosis of liver metastases, in particular of colorectal liver metastases, focusing on the most accurate method (diffusion-weighted imaging combined with gadoxetic acid-enhanced MRI), possible reasons for the lack of its diffusion in the guidelines, and possible future scenarios
Phonon and light read out of a Li 2MoO 4 crystal with multiplexed kinetic inductance detectors
Molybdenum based crystals such as Li 2MoO 4 and CaMoO4 are emerging as leading candidates for next generation experiments searching for neutrino-less double beta decay with cryogenic calorimeters (CUPID, AMoRE). The exquisite energy resolution and high radio-purity of these crystals come at the cost of a potentially detrimental background source: the two neutrinos double beta decay of 100Mo. Indeed, the fast half-life of this decay mode, combined with the slow response of cryogenic calorimeters, would result in pile-up events in the energy region of interest for neutrino-less double beta decay, reducing the experimental sensitivity. This background can be suppressed using fast and high sensitivity cryogenic light detectors, provided that the scintillation time constant itself does not limit the time resolution. We developed a new detection technique exploiting the high sensitivity, the fast time response and the multiplexing capability of Kinetic Inductance Detectors. We applied the proposed technique to a 2 × 2 × 2 cm3Li 2MoO 4 crystal, which was chosen as baseline option for CUPID. We measured simultaneously both the phonon and scintillation signals with KIDs. We derived the scintillation time constant of this compound at millikelvin temperatures obtaining tscint= 84.5 ± 4.5 (syst) ± 1.0 (stat) µs, constant between 10 and 190 mK
Aptitud de dos sedimentitas rojas cretácicas del departamento Confluencia, Neuquén, para ser usadas como barreras aislantes en rellenos sanitarios
En este trabajo se presenta la caracterización de dos sedimentitas de grano fino del departamento Confluencia, Neuquén, que forman parte de las formaciones Huincul y Anacleto (Grupo Neuquén - Cretácico Superior) con el objetivo dedeterminar su aptitud para ser usadas como materiales para impermeabilizar la base de rellenos sanitarios. Las muestras fueron extraÃdas de dos canteras inactivas de arcillas rojas, explotadas como materia prima para la industria de la cerámica, y representan el material que se comercializaba para este fin. Los resultados fueron comparados con una bentonita sódica natural comercial la cual se utilizó como material de referencia. En función de la distribución del tamaño de partÃculas, las sedimentitas se clasifican como una fangolita (F. Huincul) y una arcilita (F. Anacleto). La mineralogÃa de la fracción arcilla de estas sedimentitas está representada principalmente por un interestratificado I/S tipo R0 (55-80% Sm). Las sedimentitas rojas ensayadas cumplieron con los requisitos de conductividad hidráulica estipulados por la legislación internacional para suuso como barrera impermeable (menor que 1 x 10-9 m/s). Su capacidad de intercambio catiónico, como también la plasticidad y compresibilidad de las mismas, demostraron un comportamiento satisfactorio para su uso en rellenos sanitarios. En mezclas con una arena mal seleccionada, el agregado de un 15% de la arcilita de la Formación Anacleto permitió superar el requisito legal de conductividad hidráulica, mientras que la fangolita de la Formación Huincul no cumplió con dicha condición. No obstante, a diferencia de una bentonita sódica natural, estas sedimentitas podrÃan ser utilizadas sin ser mezcladas con otros materiales naturales (suelos o arena) por su baja compresibilidad y menor potencial expansivo. El uso de los materiales ensayados en el diseño de sistemas de impermeabilización de rellenos sanitarios constituirÃa una alternativa efectiva no sólo porque cumplen con los requisitos técnicos estipulados para este fin, sino también por su abundancia y bajo costo de extracción en el área de estudio
Reducing the impact of radioactivity on quantum circuits in a deep-underground facility
As quantum coherence times of superconducting circuits have increased from
nanoseconds to hundreds of microseconds, they are currently one of the leading
platforms for quantum information processing. However, coherence needs to
further improve by orders of magnitude to reduce the prohibitive hardware
overhead of current error correction schemes. Reaching this goal hinges on
reducing the density of broken Cooper pairs, so-called quasiparticles. Here, we
show that environmental radioactivity is a significant source of nonequilibrium
quasiparticles. Moreover, ionizing radiation introduces time-correlated
quasiparticle bursts in resonators on the same chip, further complicating
quantum error correction. Operating in a deep-underground lead-shielded
cryostat decreases the quasiparticle burst rate by a factor fifty and reduces
dissipation up to a factor four, showcasing the importance of radiation
abatement in future solid-state quantum hardware
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