Effective Mass Research Articles

Tunable plasmon-induced transparency in anisotropic graphene-black phosphorus photonic device for high-performance sensors and switchers

A novel photonic device composed of graphene and black phosphorus (G-BP) has been proposed, which achieves high-performance plasmon-induced transparency (PIT) effect within the THz range and maintains substantial tunability and anisotropy. The anisotropy of the PIT effect arises from the near-field coupling between two bright modes characterized by distinct effective electron masses of BP, resulting transparency window at 33.35 THz for TE polarization and at 26.92 THz for TM polarization. Through the modulation of Fermi energy in graphene, doping levels of BP and geometric parameters separately, a tunable transparency window is achieved. Notably, the convergence or divergence of the anisotropic transparency windows can be well manipulated with different BP doping levels. Furthermore, the proposed G-BP photonic device exhibits a high sensitivity to changes in the surrounding refractive index and substrates, with a maximum sensitivity of 12.04 THz/RI, rendering it suitable for sensor applications. Overall, the proposed photonic device exhibits notable PIT effects characterized by high anisotropic performance, substantial tunability, great sensitivity, and stability, making it a promising candidate for applications in sensors, polarizers, and switchers.

Isotope effects and Alfvén eigenmode stability in JET H, D, T, DT, and He plasmas

Abstract While much about Alfvén eigenmode (AE) stability has been explored in previous and current tokamaks, open questions remain for future burning plasma experiments, especially regarding exact stability threshold conditions and related isotope effects; the latter, of course, requiring good knowledge of the plasma ion composition. In the JET tokamak, eight in-vessel antennas actively excite stable AEs, from which their frequencies, toroidal mode numbers, and net damping rates are assessed. The effective ion mass can also be inferred using measurements of the plasma density and magnetic geometry. Thousands of AE stability measurements have been collected by the Alfvén Eigenmode Active Diagnostic in hundreds of JET plasmas during the recent Hydrogen, Deuterium, Tritium, DT, and Helium-4 campaigns. In this novel AE stability database, spanning all four main ion species, damping is observed to decrease with increasing Hydrogenic mass, but increase for Helium, a trend consistent with radiative damping as the dominant damping mechanism. These data are important for confident predictions of AE stability in both non-nuclear (H/He) and nuclear (D/T) operations in future devices. In particular, if radiative damping plays a significant role in overall stability, some AEs could be more easily destabilized in D/T plasmas than their H/He reference pulses, even before considering fast ion and alpha particle drive. Active MHD spectroscopy is also employed on select HD, HT, and DT plasmas to infer the effective ion mass, thereby closing the loop on isotope analysis and demonstrating a complementary method to typical diagnosis of the isotope ratio.

Unveiling the quasiparticle behaviour in the pressure-induced high-Tc phase of an iron-chalcogenide superconductor

Superconductivity of iron chalocogenides is strongly enhanced under applied pressure yet its underlying pairing mechanism remains elusive. Here, we present a quantum oscillations study up to 45 T in the high-Tc phase of tetragonal FeSe0.82S0.18 up to 22 kbar. Under applied pressure, the quasi-two-dimensional multi-band Fermi surface expands and the effective masses remain large, whereas the superconductivity displays a threefold enhancement. Comparing with chemical pressure tuning of FeSe1−xSx, the Fermi surface expands in a similar manner but the effective masses and Tc are suppressed. These differences may be attributed to the changes in the density of states influenced by the chalcogen height, which could promote stronger spin fluctuations pairing under pressure. Furthermore, our study also reveals unusual scattering and broadening of superconducting transitions in the high-pressure phase, indicating the presence of a complex pairing mechanism.

Linear and nonlinear exciton polariton dispersion in MoS2 nanosheets and its nickel doping dependence.

Abstract In this paper, we study the influence of Ni-doping on A- and B-exciton polariton dispersion in MoS2 nanosheets. In particular, we have calculated the effect of the Ni-concentration on the energy dispersion and therefore we have deduced the effective masses by adjusting the hopping parameter. The EA, EB-exciton transition energies and the hopping parameter are discerned from the PL of Ni-MoS2 nanosheets. It is shown that the Ni changes considerably the bandgap and as a result the electronic band structure, the effective masses, the optical transition, and the hopping term. We found that the increasing concentration of Ni-dopant can modulate and favors the mixture of A- and B-exciton peaks of MoS2 nanosheets. The diverging Ni-concentration of A- and B-exciton polariton dispersion are also discerned and discussed. Finaly, we can predict that these changes caused by the influence of Ni-doping can be used in most applications involving exciton polariton dispersion for photonics and optoelectronics devices.

Variation in parasitoid adult size is related to host egg size, maternal state and developmental time

AbstractBody size is a characteristic of many animal species that is correlated with many fitness‐related traits. Parasitoids are important biological control agents of pests; larger parasitoids often have greater fitness and enhanced performance. Host size is a major influence on parasitoid size, which has been explored in the important egg parasitoid Anastatus disparis (Hymenoptera: Eupelmidae), a potential biological control agent for several Lepidopteran pests. Here, we found that the body size of A. disparis females increased with increasing host egg size, while host egg size did not significantly affect male size. In addition, both female and male offspring sizes significantly increased with increasing maternal size, and female offspring produced by younger mothers were also larger. Furthermore, the body sizes of both females and males appeared to increase when the total development time from egg to adult eclosion decreased. Male offspring produced by larger females have shorter development times, while female offspring produced by older females have longer development times. Consequently, our results suggested that the effect of maternal status on offspring size may be mediated by influencing development time. In summary, our results indicated that the body size of A. disparis is determined by multiple factors with differing effects on females and males, and our results provide guidance for its effective mass rearing and its performance in the field.

Radicular (periapical) cyst causing exophthalmos in a dog

AbstractA 10‐year‐old male neutered Bichon Frise presented for assessment of right unilateral exophthalmos. The ophthalmological assessment revealed signs of retrobulbar disease. Computed tomography of the head showed a cavitary, well‐defined, fluid‐filled structure, which displayed a strong peripheral rim of contrast enhancement, and was centred around the tooth roots of the right maxillary first and second molar teeth (109 and 110). Focused ultrasound‐guided fluid sampling and fine needle aspirates were obtained for diagnostic purposes. After discussing the case with a veterinary dentist, extraction of the 109 and 110 and debridement of the cyst were performed. Histopathology supported the suspicion of a radicular cyst. Radicular cysts, despite being benign lesions, need to be included as a possible differential in cases with exophthalmos due to their potential retrobulbar mass effect.

Effective photon mass in the presence of gravity gradient emulated by an electromagnetic medium

Effective photon mass in the presence of gravity gradient emulated by an electromagnetic medium

Calculation electrical conductivity a two-dimensional electron gas of AlGaN/GaN-based transistors with high electron mobility

An analytical expression of the integral electrical conductivity of a semiconductor nanolayer, the charge carriers of which are located in a triangular quantum well, is obtained. The isoenergetic surface of the semiconductor material has the shape of a triaxial ellipsoid. The charge carrier behavior is described by the quantum Liouville equation. The dependence of electrical conductivity on dimensionless parameters is analyzed: the transverse electric field strength, the longitudinal electric field frequency, the charge carrier effective masses and the heterointerface specular coefficient. It is established that the conductivity of a triangular well compared to a rectangular well is more dependent on the effective mass, which to allow to select a material with the best high-frequency properties.

Standardized reporting for Head CT Scans in patients suspected of traumatic brain injury (TBI): An international expert endeavor.

Traumatic brain injury (TBI) is a major source of health loss and disability worldwide. Accurate and timely diagnosis of TBI is critical for appropriate treatment and management of the condition. Neuroimaging plays a crucial role in the diagnosis and characterization of TBI. Computed tomography (CT) is the first-line diagnostic imaging modality typically utilized in patients with suspected acute mild, moderate and severe TBI. Radiology reports play a crucial role in the diagnostic process, providing critical information about the location and extent of brain injury, as well as factors that could prevent secondary injury. However, the complexity and variability of radiology reports can make it challenging for healthcare providers to extract the necessary information for diagnosis and treatment planning. In this article, we report the efforts of an international group of TBI imaging experts to develop a clinical radiology report template for CT scans obtained in patients suspected of TBI and consisting of fourteen different subdivisions (CT technique, mechanism of injury or clinical history, presence of scalp injuries, fractures, potential vascular injuries, potential injuries involving the extra-axial spaces, brain parenchymal injuries, potential injuries involving the cerebrospinal fluid spaces and the ventricular system, mass effect, secondary injuries, prior or coexisting pathology).

The band structure of a chain of periodically ordered different quantum dots

The paper introduces a model for a superlattice comprising periodically arranged quantum dots (QDs) and proposes a method for calculating the energy spectrum. This theory was applied to a chain of QDs. The study employed the effective mass approximation and solved the Schrödinger equation using the tight-binding model and nearest neighbor approximation. The energy spectra of electrons were determined as functions of the wave vector, and the theory facilitated the calculation of dispersion dependencies and bandwidths. The presence of different QDs resulted in the subdivision of the mini-zone into upper and lower zones. It was demonstrated and analyzed that the width of the upper zones consistently exceeds that of the lower ones. Furthermore, when the QDs possess identical sizes and materials, no forbidden zone is observed.

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Top-quark pair production in association with two b-jets is computed at next-to-leading order QCD precision, including effects of the b-quark mass, and matched to a tt¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t} $$\\end{document}+jets simulation in a variable flavor number scheme. The Monte Carlo realization of this method, called fusing, consistently embeds the four-flavor calculation in a particle-level event generator. As a first phenomenological application, we present observables relevant to the data-driven estimation of irreducible backgrounds to tt¯H\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t}H $$\\end{document}-production.

MRI Imaging Appearance in Mullerian Duct Anomalies

Abstract Background Müllerian duct anomalies include a complex spectrum of anatomical anomalies that arise from deviations during the normal development of the Müllerian ducts. In paediatrics, such defects cannot present with any clinical symptoms before puberty, yet, they can also have obstructive symptoms or a mass effect due to presence of a non communicating rudimentary horn or transverse vaginal septum. At the beginning of puberty, girls with these anomalies might have primary amenorrhea, pelvic pain or endometriosis. Müllerian duct anomalies have also associated with a variety of other congenital abnormalities. Aim of the Work To review MRI features of Mullerian Duct Anomalies and classify them according to ASRM and ESHRE-ESGE classifications. Patients and Methods The study was a case series study that included 37 patients who underwent pelvic MRI at Radiology Department “Ain Shams University hospitals” in Cairo, Egypt. Results In our study, Hypoplastic, Agenesis and Didelphysis found to have the same ratio of (21.6%), while Bicornuate uterus was (13.5%), septate (8.1%), unicornuate and transverse vaginal septum all were of (5.4%) incidence and the least common was arcuate uterus with (2.7%) incidence. Conclusion MRI is a highly helpful technique for evaluating female genital abnormalities and is able to consistently provide the essential imaging characteristics for the accurate identification of Mullerian malformations. Additionally, incidental pelvic disease and any related renal abnormalities may be thoroughly evaluated by MRI in a single scan, removing the need for additional diagnostic procedures.

Association of Dynamic Trajectories of Time-Series Data and Life-Threatening Mass Effect in Large Middle Cerebral Artery Stroke.

Life-threatening, space-occupying mass effect due to cerebral edema and/or hemorrhagic transformation is an early complication of patients with middle cerebral artery stroke. Little is known about longitudinal trajectories of laboratory and vital signs leading up to radiographic and clinical deterioration related to this mass effect. We curated a retrospective data set of 635 patients with large middle cerebral artery stroke totaling 95,463 data points for 10 longitudinal covariates and 40 time-independent covariates. We assessed trajectories of the 10 longitudinal variables during the 72h preceding three outcomes representative of life-threatening mass effect: midline shift ≥ 5mm, pineal gland shift (PGS) > 4mm, and decompressive hemicraniectomy (DHC). We used a "backward-looking" trajectory approach. Patients were aligned based on outcome occurrence time and the trajectory of each variable was assessed before that outcome by accounting for cases and noncases, adjusting for confounders. We evaluated longitudinal trajectories with Cox proportional time-dependent regression. Of 635 patients, 49.0% were female, and the mean age was 69years. Thirty five percent of patients had midline shift ≥ 5mm, 24.3% of patients had PGS > 4mm, and 10.7% of patients underwent DHC. Backward-looking trajectories showed mild increases in white blood cell count (10-11K/UL within 72h), temperature (up to half a degree within 24h), and sodium levels (1-3mEq/L within 24h) before the three outcomes of interest. We also observed a decrease in heart rate (75-65 beats per minute) 24h before DHC. We found a significant association between increased white blood cell count with PGS > 4mm (hazard ratio 1.05, p value 0.007). Longitudinal profiling adjusted for confounders demonstrated that white blood cell count, temperature, and sodium levels appear to increase before radiographic and clinical indicators of space-occupying mass effect. These findings will inform the development of multivariable dynamic risk models to aid prediction of life-threatening, space-occupying mass effect.

Universal strain engineering for enhancing the hole mobility and dopability in p-type semiconductors

Modern electronic and optoelectronic devices rely on the development of the complementary pair of n-type and p-type semiconductors. However, it is often seen that n-type semiconductors are easier to realize and offer superior performances than their p-type counterparts, with p-type semiconductors showing much lower hole mobility and inefficient carrier doping. Here, by using first-principles studies, we demonstrate that lattice strain engineering can be a universal approach to enhance the hole mobility and dopability in p-type semiconductors. A broad class of p-type semiconductors, including anion p orbital derived valence band compounds (nitrides, oxides, halides, and chalcogenides), s orbital based post-transition metal oxides (e.g., SnO), and d-orbital based transition metal oxides (e.g., NiO), have been applied on strain to demonstrate their valence band modulation ability for the purpose of increasing the hole mobility and p-type dopability. We show that compressive lattice strain generally results in an upshifted valence band edge and reduced effective hole mass, leading to enhanced p-type dopability and increased hole mobility. Our work highlights strain engineering as a universal and effective approach for achieving better performed p-type compound semiconductors.

Trigeminal Microvascular Decompression and Meckel's Cave Tumor Resection via Retrosigmoid Approach With Suprameatal Extension: 2-Dimensional Operative Video.

The leading cause of trigeminal neuralgia (TGN) relies on the microvascular conflict between the superior cerebellar artery (SCA) loop and the dorsal root entry zone of the trigeminal nerve (TN). However, lesions along the TN have been described as a possible cause of TGN for direct mass effect or indirect vascular transposition. Thus, the surgical approach to TGN in patients harboring cerebellopontine angle or Meckel's cave tumor should be methodically chosen. The retrosigmoid (RS) approach with suprameatal extension offers direct access to the TN in both its cisternal and Meckel's cave segment, allowing optimal TN decompression from vascular and tumoral components. Although the RS approach with suprameatal extension has been described in numerous studies,1-4 videos detailing its key steps in addressing a multicomponent TGN are lacking. In this video, we highlight the case of a 46 year-old woman with 6 months of medically refractory typical TGN with a right en plaque meningioma involving the petrous bone, petroclival junction, Meckel's cave, and tentorium. In addition, magnetic resonance imaging was suspicious for a compressive SCA loop over the dorsal root entry zone. The patient underwent a RS approach with suprameatal extension for subtotal resection of the tumor and microvascular decompression of the TGN. The patient recovered with no complications and TGN resolved.

Extended uncertainty principle: A deeper insight into the Hubble tension?

The standard cosmological model, known as the ΛCDM model, has been successful in many respects, but it has some significant discrepancies, some of which have not been resolved yet. In measuring the Hubble-Lemaître parameter, there is an apparent discrepancy which is known as the Hubble tension, defined as differences in values of this parameter measured by the Type Ia Supernovae (SNeIa) data (a model-independent method) and by the Cosmic Microwave Background (CMB) radiation maps (a model-dependent method). Although many potential solutions have been proposed, the issue still remains unresolved. Recently, it was observed that the Hubble tension can be due to the concept of uncertainty in measuring cosmological parameters at large distance scales through applying the Heisenberg Uncertainty Principle (HUP) in cosmological setups. Extending this pioneering idea, in the present study we plan to incorporate the Extended Uncertainty Principle (EUP) containing a minimal fundamental measurable momentum (or equivalently, a maximal fundamental measurable length) as a candidate setup for describing large-scale effects of Quantum Gravity (QG) to address the Hubble tension and constrain the EUP length scale. In this regard, by finding a relevant formula for the effective photon rest mass in terms of the present-time value of the Hubble-Lemaître parameter, we see that discrepancies in the value of photon rest mass associated with the Hubble-Lemaître parameter values estimated from model-independent and model-dependent methods perhaps is the cause of Hubble tension. We show explicitly that the presence of a non-zero minimal uncertainty in momentum (or non-zero maximal uncertainty in position) measurements as a consequence of the large distance quantum gravity effect addresses the Hubble tension satisfactorily without having to invoke new physics. Moreover, we use the formula for the effective photon rest mass to find some relevant lower bounds on the EUP length scale.

Evaluating the impact of filler size and filler content on the stiffness, strength, and toughness of polymer nanocomposites using coarse-grained molecular dynamics

Their great versatility makes polymer nanocomposites an important class of engineering materials. In order to gain detailed insights into the nanoscale mechanisms underlying their macroscopic mechanical properties, molecular dynamics (MD) simulations are a valuable tool to complement experimental studies. In this work, we modify the analytical potential functions of an efficient bead–spring model representing a generic polymer nanocomposite to account for the breaking of covalent bonds. We perform uniaxial tensile simulations of double-notched specimens and validate the model using experimental trends for overall stiffness, strength, and toughness. First, we study the effects of sample size, notch geometry, strain rate, temperature, and molar mass for the pure thermoplastic matrix material. Second, we analyze the influence of filler size and filler content on the mechanical behavior of the polymer nanocomposite. With this study, we show that in both the development of new materials and the optimization of established materials, it is possible to gain important preliminary insights into the effects of pertinent material characteristics with a simple MD setup, which can then be further refined by increasing the complexity of the material description and the boundary conditions.

Impact of the unimodal molar mass distribution on the mechanical behavior of polymer nanocomposites below the glass transition temperature: A generic, coarse-grained molecular dynamics study

Polymer nanocomposites (PNCs) have shown great potential to meet the ever-growing requirements of modern engineering applications. Nowadays, molecular dynamics (MD) simulations are increasingly employed to complement experimental work and thereby gain a deeper understanding of the complex structure–property relations of PNCs. However, with respect to the thermoplastic’s mechanical behavior, the role of its average molar mass M¯n is rarely addressed, and many MD studies only consider uniform (monodispersed) polymers. Therefore, this contribution investigates the impact that M¯n and the dispersity Đ have on the stiffness and strength of PNCs through coarse-grained MD. To this end, we employed a Kremer–Grest bead–spring model and observed the expected increase in the mechanical performance of the neat polymer for larger M¯n. Our results indicated that the unimodal molar mass distribution does not impact the mechanical behavior in the investigated dispersity range 1.0≤Đ≤1.09. For the PNC, we obtained the same M¯n-dependence and Đ-independence of the mechanical properties over a wide range of filler sizes and contents. This contribution proves that even simple MD models can reproduce the experimentally well researched effect of the molar mass. Hence, this work is an important step in understanding the complex structure–property relations of PNCs, which is essential to unlock their full potential.

Performance investigation of a novel free piston Stirling pump for reverse osmosis desalination systems

Renewable energy (RE)-powered desalination technology is considered a cleaner and promising alternative for alleviating energy exhaustion and environmental pollution resulting from traditional desalination. Currently available solar thermal reverse osmosis (RO) desalination systems are based on the organic Rankine cycle. With the aim to expand the driving mode of reverse osmosis desalination as well as simplify the transmission chain and reduce mechanical energy losses, a novel hydraulic free piston Stirling pump (FPSP) is developed and a simple model is designed and tested for conceptual validation. A free piston Stirling pump - powered reverse osmosis desalination system is presented, and a thermodynamic–dynamic coupling model is established. A parametric analysis is performed with an emphasis on the effects of temperatures, charge pressure, spring stiffnesses, damping coefficients, and masses on the system performance, including the frequency, power output, water yield, and efficiency. Results showed that the frequency in the pumping process was higher than that in the suction process because of the different loads. Within the range investigated, the performance improved as the hot-end temperature, charge pressure, spring stiffnesses, and damping coefficient of the power piston increased, while it deteriorated with a decrease in the damping coefficient of the displacer and the piston masses. Specifically, the power output and water yield reached the optimum value as the cold-end temperature was maintained around 310 K. Under representative parameter conditions, the power output could reach 12.15 kW and the water yield was approximately 6.07 × 10−4 m3/s. In addition, the temperatures and charge pressure influence the system efficiency most.

Peculiar Velocity Reconstruction from Simulations and Observations Using Deep Learning Algorithms

In this paper, we introduce a U-Net model of deep learning algorithms for reconstructions of the 3D peculiar velocity field, which simplifies the reconstruction process with enhanced precision. We test the adaptability of the U-Net model with simulation data under more realistic conditions, including the redshift space distortion effect and halo mass threshold. Our results show that the U-Net model outperforms the analytical method that runs under ideal conditions, with a 16% improvement in precision, 13% in residuals, 18% in correlation coefficient, and 27% in average coherence. The deep learning algorithm exhibits exceptional capacities to capture velocity features in nonlinear regions and substantially improve reconstruction precision in boundary regions. We then apply the U-Net model trained under Sloan Digital Sky Survey (SDSS) observational conditions to the SDSS Data Release 7 data for observational 3D peculiar velocity reconstructions.