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- Alkurtass, B., et al.
(författare)
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Entanglement structure of the two-channel Kondo model
- 2016
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Ingår i: Physical Review B. - 2469-9950. ; 93:8
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Tidskriftsartikel (refereegranskat)abstract
- Two electronic channels competing to screen a single impurity spin, as in the two-channel Kondo model, are expected to generate a ground state with a nontrivial entanglement structure. We exploit a spin-chain representation of the two-channel Kondo model to probe the ground-state block entropy, negativity, tangle, and Schmidt gap, using a density matrix renormalization group approach. In the presence of symmetric coupling to the two channels, we confirm field-theory predictions for the boundary entropy difference ln(g(UV)/g(IR)) = ln(2)/2 between the ultraviolet and infrared limits and the leading ln(x)/x impurity correction to the block entropy. The impurity entanglement S-imp is shown to scale with the characteristic length xi(2CK). We show that both the Schmidt gap and the entanglement of the impurity with one of the channels-as measured by the negativity-faithfully serve as order parameters for the impurity quantum phase transition appearing as a function of channel asymmetry, allowing for explicit determination of critical exponents, nu approximate to 2 and beta approximate to 0.2. Remarkably, we find the emergence of tripartite entanglement only in the vicinity of the critical channel-symmetric point.
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- Bayat, A., et al.
(författare)
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Nonequilibrium critical scaling in quantum thermodynamics
- 2016
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Ingår i: Physical Review B. - 2469-9950. ; 93:20
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Tidskriftsartikel (refereegranskat)abstract
- The emerging field of quantum thermodynamics is contributing important results and insights into archetypal many-body problems, including quantum phase transitions. Still, the question whether out-of-equilibrium quantities, such as fluctuations of work, exhibit critical scaling after a sudden quench in a closed system has remained elusive. Here, we take a novel approach to the problem by studying a quench across an impurity quantum critical point. By performing density matrix renormalization group computations on the two-impurity Kondo model, we are able to establish that the irreversible work produced in a quench exhibits finite-size scaling at quantum criticality. This scaling faithfully predicts the equilibrium critical exponents for the crossover length and the order parameter of the model, and, moreover, implies an exponent for the rescaled irreversible work. By connecting the irreversible work to the two-impurity spin correlation function, our findings can be tested experimentally.
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- Bayat, A., et al.
(författare)
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Quantum thermodynamics at impurity quantum phase transitions
- 2020
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989. ; 239, s. 361-373
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Tidskriftsartikel (refereegranskat)abstract
- The study of quantum thermodynamics, i.e. equilibrium and non-equilibrium thermodynamics of quantum systems, has been applied to various many-body problems, including quantum phase transitions. An important question is whether out-of-equilibrium quantities from this emerging field, such as fluctuations of work, exhibit scaling after a sudden quench. In particular, it is very interesting to explore this problem in impurity models where the lack of an obvious symmetry breaking at criticality makes it very challenging to characterize. Here, by considering a spin emulation of the two impurity Kondo model and performing density matrix renormalization group computations, we establish that the irreversible work produced in a quench exhibits finite-size scaling at quantum criticality. Our approach predicts the equilibrium critical exponents for the crossover length and the order parameter of the model, and, moreover, implies a new exponent for the rescaled irreversible work. © Springer Nature Switzerland AG 2020.
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- Borges, João Batista, et al.
(författare)
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Zero expiratory pressure and low oxygen concentration promote heterogeneity of regional ventilation and lung densities
- 2016
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Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 60:7, s. 958-968
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundIt is not well known what is the main mechanism causing lung heterogeneity in healthy lungs under mechanical ventilation. We aimed to investigate the mechanisms causing heterogeneity of regional ventilation and parenchymal densities in healthy lungs under anesthesia and mechanical ventilation. MethodsIn a small animal model, synchrotron imaging was used to measure lung aeration and regional-specific ventilation (sV.). Heterogeneity of ventilation was calculated as the coefficient of variation in sV. (CVsV.). The coefficient of variation in lung densities (CVD) was calculated for all lung tissue, and within hyperinflated, normally and poorly aerated areas. Three conditions were studied: zero end-expiratory pressure (ZEEP) and FIO2 0.21; ZEEP and FIO2 1.0; PEEP 12 cmH(2)O and F(I)O(2)1.0 (Open Lung-PEEP = OLP). ResultsThe mean tissue density at OLP was lower than ZEEP-1.0 and ZEEP-0.21. There were larger subregions with low sV. and poor aeration at ZEEP-0.21 than at OLP: 12.9 9.0 vs. 0.6 +/- 0.4% in the non-dependent level, and 17.5 +/- 8.2 vs. 0.4 +/- 0.1% in the dependent one (P = 0.041). The CVsV. of the total imaged lung at PEEP 12 cmH(2)O was significantly lower than on ZEEP, regardless of FIO2, indicating more heterogeneity of ventilation during ZEEP (0.23 +/- 0.03 vs. 0.54 +/- 0.37, P = 0.049). CVD changed over the different mechanical ventilation settings (P = 0.011); predominantly, CVD increased during ZEEP. The spatial distribution of the CVD calculated for the poorly aerated density category changed with the mechanical ventilation settings, increasing in the dependent level during ZEEP. ConclusionZEEP together with low FIO2 promoted heterogeneity of ventilation and lung tissue densities, fostering a greater amount of airway closure and ventilation inhomogeneities in poorly aerated regions.
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19. |
- Gille, T., et al.
(författare)
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ERS International Congress 2021: highlights from the Respiratory Clinical Care and Physiology Assembly
- 2022
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Ingår i: European Respiratory Journal Open Research (ERJ Open Research). - : European Respiratory Society (ERS). - 2312-0541. ; 8:2
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Tidskriftsartikel (refereegranskat)abstract
- It is a challenge to keep abreast of all the clinical and scientific advances in the field of respiratory medicine. This article contains an overview of laboratory-based science, randomised controlled trials and qualitative research that were presented during the 2021 European Respiratory Society International Congress within the sessions from the five groups of the Assembly 1 - Respiratory clinical care and physiology. Selected presentations are summarised from a wide range of topics: clinical problems, rehabilitation and chronic care, general practice and primary care, electronic/mobile health (e-health/m-health), clinical respiratory physiology, exercise and functional imaging.
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- Haschka, J, et al.
(författare)
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Identification of circulating microRNA patterns in patients in psoriasis and psoriatic arthritis
- 2023
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Ingår i: Rheumatology (Oxford, England). - : Oxford University Press (OUP). - 1462-0332 .- 1462-0324. ; 62:10, s. 3448-3458
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Tidskriftsartikel (refereegranskat)abstract
- ObjectivemiRNAs are small non-coding RNAs that control gene expression. Specific intra- and extracellular miRNA signatures have been identified in various diseases. Whether certain miRNA signatures are associated with psoriasis (PsO) and PsA is currently unknown. We aimed to search for circulating miRNA signatures associated with PsO and PsA patients.MethodsExpression of miRNAs was analysed by reverse transcription quantitative real-time PCR (RT-qPCR) in the serum of PsA, PsO patients and healthy controls. Demographic and disease-specific characteristics and imaging data from hand MRI were recorded. In the discovery phase, 192 miRNA assays were analysed in 48 samples (PsA, PsO, controls: each N = 16). For validation, 17 selected miRNAs were measured in the total population.ResultsA total of 141 patients and controls were analysed (51 PsA, 40 PsO, 50 controls). In the discovery phase 51 miRNAs in PsO and 64 miRNAs in PsA were down- or upregulated compared with controls, with 33 miRNAs being changed in both (adj. P < 0.05). The 17 top candidates from discovery were assessed in the validation phase, 9 of them discriminated PsA and PsO from controls [area under the curve (AUC) ≥0.70, all P < 0.05]. Four miRNAs (miR-19b-3p, miR-21-5p, miR-92a-3p and let-7b-5p) were significantly differently regulated between PsO and PsA. A combination of these miRNAs increased the AUC to 0.92 in multivariate regression model to discriminate PsO and PsA.ConclusionmiRNA signatures in PsA and PsO patients differ from controls. Nine miRNAs were differentially regulated in PsA and PsO patients, five of them previously reported to be involved in bone and cartilage metabolism, indicating an intimate association of psoriatic inflammation and bone/cartilage changes.
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- Porra, L., et al.
(författare)
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Quantitative Imaging of Regional Aerosol Deposition, Lung Ventilation and Morphology by Synchrotron Radiation CT
- 2018
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- To understand the determinants of inhaled aerosol particle distribution and targeting in the lung, knowledge of regional deposition, lung morphology and regional ventilation, is crucial. No single imaging modality allows the acquisition of all such data together. Here we assessed the feasibility of dual-energy synchrotron radiation imaging to this end in anesthetized rabbits; both in normal lung (n = 6) and following methacholine (MCH)-induced bronchoconstriction (n = 6), a model of asthma. We used K-edge subtraction CT (KES) imaging to quantitatively map the regional deposition of iodine-containing aerosol particles. Morphological and regional ventilation images were obtained, followed by quantitative regional iodine deposition maps, after 5 and 10 minutes of aerosol administration. Iodine deposition was markedly inhomogeneous both in normal lung and after induced bronchoconstrition. Deposition was significantly reduced in the MCH group at both time points, with a strong dependency on inspiratory flow in both conditions (R-2 = 0.71; p < 0.0001). We demonstrate for the first time, the feasibility of KES CT for quantitative imaging of lung deposition of aerosol particles, regional ventilation and morphology. Since these are among the main factors determining lung aerosol deposition, we expect this imaging approach to bring new contributions to the understanding of lung aerosol delivery, targeting, and ultimately biological efficacy.
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- Zhang, J., et al.
(författare)
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Designing against phase and property heterogeneities in additively manufactured titanium alloys
- 2022
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Additive manufacturing (AM) creates digitally designed parts by successive addition of material. However, owing to intrinsic thermal cycling, metallic parts produced by AM almost inevitably suffer from spatially dependent heterogeneities in phases and mechanical properties, which may cause unpredictable service failures. Here, we demonstrate a synergistic alloy design approach to overcome this issue in titanium alloys manufactured by laser powder bed fusion. The key to our approach is in-situ alloying of Ti−6Al−4V (in weight per cent) with combined additions of pure titanium powders and iron oxide (Fe2O3) nanoparticles. This not only enables in-situ elimination of phase heterogeneity through diluting V concentration whilst introducing small amounts of Fe, but also compensates for the strength loss via oxygen solute strengthening. Our alloys achieve spatially uniform microstructures and mechanical properties which are superior to those of Ti−6Al−4V. This study may help to guide the design of other alloys, which not only overcomes the challenge inherent to the AM processes, but also takes advantage of the alloy design opportunities offered by AM.
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28. |
- Bayat, A., et al.
(författare)
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Entanglement Probe of Two-Impurity Kondo Physics in a Spin Chain
- 2012
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Ingår i: Physical Review Letters. - 0031-9007. ; 109:6
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Tidskriftsartikel (refereegranskat)abstract
- We propose that real-space properties of the two-impurity Kondo model can be obtained from an effective spin model where two single-impurity Kondo spin chains are joined via an Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between the two impurity spins. We then use a density matrix renormalization group approach, valid in all ranges of parameters, to study its features using two complementary quantum-entanglement measures, the negativity and the von Neumann entropy. This nonperturbative approach enables us to uncover the precise dependence of the spatial extent xi(K) of the Kondo screening cloud with the Kondo and RKKY couplings. Our results reveal an exponential suppression of the Kondo temperature T-K similar to 1/xi(K) with the size of the effective impurity spin in the limit of large ferromagnetic RKKY coupling, a striking display of "Kondo resonance narrowing" in the two-impurity Kondo model. We also show how the antiferromagnetic RKKY interaction produces an effective decoupling of the impurities from the bulk already for intermediate strengths of this interaction, and, furthermore, exhibit how the non-Fermi liquid quantum critical point is signaled in the quantum entanglement between various parts of the system.
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29. |
- Bayat, A., et al.
(författare)
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Measurement Quench in Many-Body Systems
- 2018
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Ingår i: Physical Review Letters. - 0031-9007. ; 121:3
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Tidskriftsartikel (refereegranskat)abstract
- Measurement is one of the key concepts which discriminates classical and quantum physics. Unlike classical systems, a measurement on a quantum system typically alters it drastically as a result of wave function collapse. Here we suggest that this feature can be exploited for inducing quench dynamics in a many-body system while leaving its Hamiltonian unchanged. Importantly, by doing away with dedicated macroscopic devices for inducing a quench-using instead the indispensable measurement apparatus only-the protocol is expected to be easier to implement and more resilient against decoherence. By way of various case studies, we show that our scheme also has decisive advantages beyond reducing decoherence-for spectroscopy purposes and probing nonequilibrium scaling of critical and quantum impurity many-body systems.
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- Bayat, A., et al.
(författare)
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Universal single-frequency oscillations in a quantum impurity system after a local quench
- 2015
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Ingår i: Physical Review B. - 1098-0121. ; 92:15
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Tidskriftsartikel (refereegranskat)abstract
- Universal single-frequency oscillations in the local nonequilibrium dynamics of a quantum many-body system are an exceptional phenomenon. In fact, till now, this has never been observed or predicted for the physically relevant case where a system is prepared to be quenched from one quantum phase to another. Here we show how the quench dynamics of the entanglement spectrum may reveal the emergence of such oscillations in a correlated quantum system with Kondo impurities. The oscillations we find are characterized by a single frequency. This frequency is independent of the amount of energy released by the local quench, and scales with the inverse system size. Importantly, the quench-independent frequency manifests itself also in local observables, such as the spin-spin correlation function of the impurities.
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- Bladen, Catherine L., et al.
(författare)
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The TREAT-NMD Duchenne Muscular Dystrophy Registries : Conception, Design, and Utilization by Industry and Academia
- 2013
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Ingår i: Human Mutation. - : Hindawi Limited. - 1059-7794 .- 1098-1004. ; 34:11, s. 1449-1457
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Tidskriftsartikel (refereegranskat)abstract
- Duchenne muscular dystrophy (DMD) is an X-linked genetic disease, caused by the absence of the dystrophin protein. Although many novel therapies are under development for DMD, there is currently no cure and affected individuals are often confined to a wheelchair by their teens and die in their twenties/thirties. DMD is a rare disease (prevalence<5/10,000). Even the largest countries do not have enough affected patients to rigorously assess novel therapies, unravel genetic complexities, and determine patient outcomes. TREAT-NMD is a worldwide network for neuromuscular diseases that provides an infrastructure to support the delivery of promising new therapies for patients. The harmonized implementation of national and ultimately global patient registries has been central to the success of TREAT-NMD. For the DMD registries within TREAT-NMD, individual countries have chosen to collect patient information in the form of standardized patient registries to increase the overall patient population on which clinical outcomes and new technologies can be assessed. The registries comprise more than 13,500 patients from 31 different countries. Here, we describe how the TREAT-NMD national patient registries for DMD were established. We look at their continued growth and assess how successful they have been at fostering collaboration between academia, patient organizations, and industry.
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- Bose, S., et al.
(författare)
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Entanglement content of many-body states via concurrence, negativity and schmidt gap
- 2020
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989. ; 239, s. 91-107
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Tidskriftsartikel (refereegranskat)abstract
- Quantum entanglement is nearly ubiquitous in equilibrium and non-equilibrium many-body states. Although it has been largely studied through the von Neumann entropy of a subsystem, which quantifies the entanglement between two complementary parts of a many-body system, this is not necessarily the only way. Here we review how some other measures can be fruitful in characterizing the entanglement content of many-body states. For example, we can look at the entangement between two individual spins through the concurrence or between two non-complementary, but in principle large, parts of a many-body system through the negativity. Alternatively, a quantity inspired through entanglement studies, but not itself a measure of entanglement, namely the Schmidt gap, can be effective as an order parameter for phase transitions in which only the entanglement structure of a many-body system changes. We exemplify using equilibrium states of short-range and impurity models and their quantum phase transitions. © Springer Nature Switzerland AG 2020.
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- Broche, Ludovic, et al.
(författare)
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Dynamic Mechanical Interactions Between Neighboring Airspaces Determine Cyclic Opening and Closure in Injured Lung
- 2017
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Ingår i: Critical Care Medicine. - 0090-3493 .- 1530-0293. ; 45:4, s. 687-694
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Positive pressure ventilation exposes the lung to mechanical stresses that can exacerbate injury. The exact mechanism of this pathologic process remains elusive. The goal of this study was to describe recruitment/derecruitment at acinar length scales over short-time frames and test the hypothesis that mechanical interdependence between neighboring lung units determines the spatial and temporal distributions of recruitment/derecruitment, using a computational model. Design: Experimental animal study. Setting: International synchrotron radiation laboratory. Subjects: Four anesthetized rabbits, ventilated in pressure controlled mode. Interventions: The lung was consecutively imaged at - 1.5-minute intervals using phase-contrast synchrotron imaging, at positive end expiratory pressures of 12, 9, 6, 3, and 0 cm H2O before and after lavage and mechanical ventilation induced injury. The extent and spatial distribution of recruitment/derecruitment was analyzed by subtracting subsequent images. In a realistic lung structure, we implemented a mechanistic model in which each unit has individual pressures and speeds of opening and closing. Derecruited and recruited lung fractions (F-derecruaed, F-recruited) were computed based on the comparison of the aerated volumes at successive time points. Measurements and Main Results: Alternative recruitment/derecruitment occurred in neighboring alveoli over short-time scales in all tested positive end-expiratory pressure levels and despite stable pressure controlled mode. The computational model reproduced this behavior only when parenchymal interdependence between neighboring acini was accounted for. Simulations closely mimicked the experimental magnitude of F-derecruited and F-recruited when mechanical interdependence was included, while its exclusion gave F-recruited values of zero at positive end -expiratory pressure greater than or equal to 3 cm H2O. Conclusions: These findings give further insight into the microscopic behavior of the injured lung and provide a means of testing protective-ventilation strategies to prevent recruitment/derecruitment and subsequent lung damage.
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- Mousavi, S. A., et al.
(författare)
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Three-Dimensional Finite Element Analysis of GaPO4/Pt Surface Acoustic Wave Resonator Based on Cell Model
- 2009
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Ingår i: International Review on Modeling and Simulations. - Italy : Praise Worthy Prize. - 1974-9821 .- 1974-983X. ; 2:4, s. 426-432
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Tidskriftsartikel (refereegranskat)abstract
- This paper present a three-dimensional finite element method for the one-port surface acoustic wave resonator base on GaPO4 with 5° cut for high frequency application. Interdigital transducer is assumed a thin film platinum with chromium as an under-layer material. The simulated frequency response and wave propagation are obtained under base cell model at 433.92 MHz centre frequency under ISM band. Frequency responses versus impedance are compared and verify with the known result in literature. The results show that the total displacements are vanished at a distance of about 2 to 3 wavelength from the surface. As expected, the X and Y displacement are 90°out-of-phase with each other. It is observed that the mass loading effect is suitable for prediction of resonant frequency. It is Q found that the factor value is larger than 1000 and the mode shapes for resonant and anti-resonant condition are different at two edges of stop-band.
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- Oosterhuis, Wytze P., et al.
(författare)
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The use of error and uncertainty methods in the medical laboratory
- 2018
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Ingår i: Clinical Chemistry and Laboratory Medicine. - : WALTER DE GRUYTER GMBH. - 1434-6621 .- 1437-4331. ; 56:2, s. 209-219
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Tidskriftsartikel (refereegranskat)abstract
- Error methods - compared with uncertainty methods - offer simpler, more intuitive and practical procedures for calculating measurement uncertainty and conducting quality assurance in laboratory medicine. However, uncertainty methods are preferred in other fields of science as reflected by the guide to the expression of uncertainty in measurement. When laboratory results are used for supporting medical diagnoses, the total uncertainty consists only partially of analytical variation. Biological variation, pre- and postanalytical variation all need to be included. Furthermore, all components of the measuring procedure need to be taken into account. Performance specifications for diagnostic tests should include the diagnostic uncertainty of the entire testing process. Uncertainty methods may be particularly useful for this purpose but have yet to show their strength in laboratory medicine. The purpose of this paper is to elucidate the pros and cons of error and uncertainty methods as groundwork for future consensus on their use in practical performance specifications. Error and uncertainty methods are complementary when evaluating measurement data.
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- Zhang, Jingqi, et al.
(författare)
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Ultrauniform, strong, and ductile 3D-printed titanium alloy through bifunctional alloy design
- 2024
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 383:6683, s. 639-645
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Tidskriftsartikel (refereegranskat)abstract
- Coarse columnar grains and heterogeneously distributed phases commonly form in metallic alloys produced by three-dimensional (3D) printing and are often considered undesirable because they can impart nonuniform and inferior mechanical properties. We demonstrate a design strategy to unlock consistent and enhanced properties directly from 3D printing. Using Ti−5Al−5Mo−5V−3Cr as a model alloy, we show that adding molybdenum (Mo) nanoparticles promotes grain refinement during solidification and suppresses the formation of phase heterogeneities during solid-state thermal cycling. The microstructural change because of the bifunctional additive results in uniform mechanical properties and simultaneous enhancement of both strength and ductility. We demonstrate how this alloy can be modified by a single component to address unfavorable microstructures, providing a pathway to achieve desirable mechanical characteristics directly from 3D printing.
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