Longitudinal Branches Research Articles

Thermal equalization design for the battery energy storage system (BESS) of a fully electric ship

The adoption of fully electric ships represents a significant step forward in addressing the environmental challenges of climate change and pollution in the shipping industry. This research details the optimized design of a battery energy storage system (BESS) and its air-cooling thermal management system for a 2000-ton bulk cargo ship. In comparison to the conventional flow splitter (FS-I), which divides airflow into 8 transverse branches, two novel designs—FS-II (dividing airflow into 2, 4, and 8 branches) and FS-III (dividing into 2, 4, 8, and 16 longitudinal and transverse branches)—were introduced. FS-II improves flow uniformity from 0.42 (FS-I) to 0.86 but results in an increased pressure drop up to 881.47 Pa. FS-III further enhances flow uniformity to 0.97 while reducing pressure drop to 191.99 Pa. The thermal performance of battery boxes with FS-I, FS-II, and FS-III was evaluated under extreme conditions and a complete voyage cycle. FS-III exhibited superior thermal regulation, maintaining Tmax consistently below 33.9°C during the entire voyage. These findings provide valuable insights for designing thermal management systems in electric ships.

Prevalence of child maltreatment in a nationwide sample of 18 to 31 year-olds in Germany

BackgroundChild maltreatment (CM) can have devastating and potentially lifelong effects for those affected and is a major contributor to mental health problems. To tackle public health problems it is crucial to have reliable data on CM. The aim of this study is to assess the prevalence and predictors of CM in a nationwide sample of the German population of young adults.MethodsThe study population (young adults aged 18 to 31 years) stems from the KiGGS Cohort study, the longitudinal branch of the German Health Interview and Examination Survey for children and adolescents. This sample meets the criteria of the United Nations Sustainable Development Goals (SDG) indicator 16.2.3. The data was collected between 2014 and 2017. CM were assessed with the Childhood Trauma Questionnaire (CTQ) in. In addition, socio-demographic variables and other known risk factors for CM were assessed. A total of 6433 (47.8% female) participants were included in the analyses. Binary logistic regression analyses were used to investigate predictors of maltreatment subtypes. Ordinal regression was used to examine their association with experience of multiple forms of CM.ResultsOverall, 18.4% (f: 20.9%, m: 16.1%) of the participants reported having experienced at least one type of CM; 6.7% (f: 8.8%, m: 4.8%) reported experiences of emotional abuse, 3.7% (f: 3.9%, m: 3.5%) physical abuse, 3.5% (f: 5.3%, m: 1.7%) sexual abuse, 9.0% (f: 9.9%, m: 8.2%) emotional neglect and 8.6% (f: 8.5%, m: 8.7%) physical neglect. Gender, subjective social status, education and household dysfunction (e.g. living with an individual who is using substances) emerged as significant predictors for different types of CM. Additionally, all these factors were significant risk factors for experiencing cumulative CM.ConclusionsCM is common in the German population, with almost one in five people experiencing at least one type of CM. The results reveal important risk factors for the occurrence of CM. In particular, people with lower social status and those who grew up in dysfunctional households are at higher risk of CM. Greater support for this vulnerable population may reduce the prevalence of CM.

Phonon Transport Characteristics of Nano-Silicon Thin Films Irradiated by Ultrafast Laser under Dispersion Relation

The gray model simplifies calculations by ignoring phonon polarization, but sacrifices a certain level of computational accuracy. In effect, the frequency and wavevector of phonons form complex polarization patterns, which means their propagation modes and vibrational directions have different influences. Therefore, based on the phonon dispersion relations in silicon, the lattice Boltzmann method is used to analyze the phonon transport characteristics in nano-silicon films under ultrafast laser excitation. The results show that the total energy density distribution obtained by superimposing acoustic and optical branches exhibits multiple wave-like behaviors. Among them, the acoustic branch has excellent transfer capability, dominating the rate at which the total energy density reaches a steady state distribution, while the optical branch has stronger heat capacity characteristics, with a greater impact on the peak value of the total energy density. When the heat transfer approaches a steady state, the longitudinal optical branch surprisingly contributes up to 52.73%. This indicates that the often-neglected optical phonons should also receive sufficient attention. Additionally, compared to the results of the gray model, it is found that the dispersion model is preferred when more attention is paid to the propagation characteristics during phonon transport.

An Investigation of the Risk Factors of Osteoporosis and the Correlation between Drug Consumption and Osteoporosis: Results of the Fasa PERSIAN Cohort Stud

Background: Osteoporosis, as the most common bone-related disease, causes massive irrecoverable consequences for the health level and life quality of people, especially at advanced ages. The present research aimed to evaluate the prevalence and risk factors of osteoporosis and the correlation between drug consumption and osteoporosis. The present study is a cross-sectional study and is the first stage in the longitudinal Fasa branch of the PERSIAN cohort study. Materials and Methods: The subjects of the present cross-sectional-descriptive study consisted of all cohort populations of Fasa University of Medical Sciences (n=10123) who were chosen through census sampling. The data were collected through a demographic data form and medication checklist, and SPSS-22 was used to analyze the data. Results: Among a total population of 10133, 994 had osteoporosis, of which 880 were women and 114 were men, which was statistically significant (P<0.05). The overall prevalence rate of osteoporosis was estimated to be 9.8%, and the mean age of people with osteoporosis was 56 years. The results demonstrated significant positive correlations among osteoporosis and age, gender, marital status, education, smoking, physical activity, alcohol use, hypertension, diabetes mellitus, fatty liver, and glucocorticoid steroid drugs (P<0.05). Conclusion: Identifying factors related to osteoporosis can be effective in adopting health promotion programs at all healthcare and prevention levels. Thus, the use of some drugs, such as corticosteroids, as an alarm and risk factor should be taken into consideration by specialists when adopting healthcare plans.

Machine learning prediction model for the axial strength of longitudinal branch plate-to-CHS T-connections

Circular hollow sections (CHS) are widely used in construction, particularly in space structures. This paper aims at investigating the feasibility of employing a machine leaning approach to predict the axial strength of longitudinal branch plate-to-CHS connections subjected to branch loadings. Using nonlinear finite element analysis, numerical models are developed for the connections subjected to tensile or compressive branch loading. The difference between the load–displacement responses for the connections under compressive and under tensile loading is established. Furthermore, the influence of various geometric and material parameters on the strength is investigated in depth. Using the results, two different strength models for the prediction of both tensile and compressive strength of longitudinal branch plate-to-CHS T-connections are developed. One prediction model is attained using traditional nonlinear regression analysis, and the other model is attained through symbolic regression. Finally, theoretical predictions are compared with numerical results, and strengths predicted with current design methodologies.

Ab initio investigations on lattice dynamics and thermal transport properties of ThO2

Thorium dioxide (ThO2) is considered as a potential substitute for uranium dioxide due to its higher melting point, higher thermal conductivity and lower thermal expansion coefficient. In this paper, based on first-principles calculations and Boltzmann transport equations (BTE), we calculate the temperature-dependent phonon dispersion and lattice thermal conductivity using self-consistent phonon (SCP) theory and the results are in good agreement with experimental values. It is worth noting that the optical vibration modes in the range of 5.5 THz to 10 THz harden significantly with the increase of temperature, leading to the gradual separation of the overlapping of the longitudinal acoustic branch and the transverse optical branch, and finally generate a band gap of 0.2 THz at 1500K, which was not found in previous studies on ThO2. After verifying the accuracy of SCP + BTE method in calculating the lattice thermal conductivity of ThO2, we predict the lattice thermal conductivity of cubic phase ThO2 in the range of 0 GPa to 30 GPa at 300K. The lattice thermal conductivity of ThO2 is 14.4 W/mK at 0 GPa and will increases to 61.9 W/mK at 30 GPa. Analysis of pressure-related thermal transport parameters reveals that the large increase in lattice thermal conductivity is mainly due to a nearly threefold increase in phonon relaxation time from 0 GPa to 30 GPa. Our analysis is of great significance for understanding the thermodynamic behavior of this new nuclear fuel at high pressure. It makes up for the lack of study on the thermal transport properties of cubic phase ThO2 under high pressure.

Interplay of charge ordering and superconductivity in two-dimensional 2H group V transition-metal dichalcogenides

Layered $2H\text{\ensuremath{-}}T{X}_{2}$ with $T=\mathrm{Nb}$, Ta and $X=\mathrm{S}$, Se exhibit rich dimensionality effects on charge density wave (CDW) order and superconductivity, but comprehensive understanding of these correlated quantum phases in the two-dimensional limit of $2H\text{\ensuremath{-}}T{X}_{2}$ is still lacking, hindering their practical applications. Here, I calculate from first principles the phonon linewidth and bare susceptibility to study the origin of CDW formation in ${\mathrm{NbSe}}_{2}$, ${\mathrm{TaS}}_{2}$, ${\mathrm{TaSe}}_{2}$, and ${\mathrm{NbS}}_{2}$ monolayers, analyze their relative CDW strength, and evaluate electron-phonon superconductivity within the fully anisotropic Migdal-Eliashberg theory. A peaked linewidth of the longitudinal acoustic branch and no Fermi-surface nesting around ${\mathbf{q}}_{\mathrm{CDW}}$ indicate CDW instability driven by the wave-vector-dependent electron-phonon coupling. The $3\ifmmode\times\else\texttimes\fi{}3$ CDW ground state favors a distinct hollow-centered clustering of transition-metal atoms, with larger distortion amplitude in ${\mathrm{NbSe}}_{2}$ and ${\mathrm{TaSe}}_{2}$ than in ${\mathrm{TaS}}_{2}$ and ${\mathrm{NbS}}_{2}$. Superconducting results of the monolayer CDW phase prove that strong spin-orbit coupling effects are dominant in determining the critical temperature ${T}_{\mathrm{c}}$ of each system via modifying both the strength and anisotropic extent of electron-phonon interactions. I also recapitulate measured opposite thickness dependencies of ${T}_{\mathrm{c}}$ in $\mathrm{Nb}{X}_{2}$ and $\mathrm{Ta}{X}_{2}$, and show that whether superconductivity is weakened or enhanced in monolayer limit relies on specific evolution of CDW-modulated Fermi-level density of states and electron-phonon matrix elements under reduced dimensionality. This work lays the foundation for applications of $2H$ group V transition-metal dichalcogenides in versatile nanoscale quantum devices.

The carrier mobility and superconducting properties of monolayer oxygen-terminated functionalized MXene Ti2CO2.

In this study, the carrier mobility of monolayer Ti2CO2 was evaluated by employing the Boltzmann transport equation and superconducting transition temperature (Tc) of Ti2CO2 was determined by utilizing the Migdal and Eliashberg formalism in the first-principles framework. In contrast to previous studies, the results reveal that optical phonons in monolayer Ti2CO2 have dominant roles in scattering processes, which significantly reduce the mobility of carriers. Alongside the rigid band model, the jellium model is implemented to investigate the screening effects on electron-phonon interactions. Based on the jellium model and full-band electron-phonon calculations, the predicted maximum electron mobility at room temperature is 38 cm2 V-1 s-1 in which 80% of the total scattering rate originates from the intra-valley transitions within the M-valleys, indicating the crucial role of the long wavelength phonon wavevectors in scattering processes. On the other hand, for the p-type material, a maximum room temperature mobility of about 285 cm2 V-1 s-1 is calculated, which can be explained by a relatively small effective mass and tiny scattering phase space. Moreover, a maximum Tc of 39 (10) K is obtained for the n-type monolayer Ti2CO2 based on the rigid (jellium) model. Outcomes indicate that the important peaks of α2F(ω) are mainly caused by the optical phonons. The remarkable couplings between the electron states and phonons are related to the non-zero slope of (near the Brillouin zone center) the longitudinal optical branch denoted by Eu caused by the displacements of oxygen and carbon atoms at intermediate and high energy ranges of phonon dispersion, respectively.

Direct Calculation of Band-Pass Filters

Introduction. When calculating band-pass filters (BPF), the circuit elements can be determined by converting the parameters of prototype low-pass filters (LPF). In a number of cases, the synthesized BPF does not have a direct prototype in the low-frequency range. Such filters include, e.g., BPFs with nodes tied to zero potential and other types of filters. Filters can be calculated directly by equating the coefficients of the synthesized filter transfer function (TF) and the realized TF obtained from the low-pass filter TF by the frequency conversion followed by solving the corresponding system of equations.Aim. To develop a methodology for direct calculation of band-pass filters with attenuation poles.Materials and methods. The simplest scheme of BPF with attenuation poles can be formed by two sequentially connected Г-shaped half-links on parallel circuits. Such a filter is realized only at certain requirements upon attenuation characteristics. When switching to BPF schemes with an additional parallel circuit in the transverse branch and a sequential circuit in the longitudinal branch, these restrictions are removed. In this paper, we develop a method for calculating inverse and quasi-elliptical BPF of П-shaped and T-shaped type, which have no restrictions when selecting the minimum attenuation and unevenness of the amplitude-frequency response (AFR).Results. The TF analytical expressions of the 6th and 10th order BPF were derived. Relations were obtained that allow the number of equations of the system for determining the filter parameters to be reduced. For П- and T-shaped 6th order BPFs, representations of circuit inductances through the central frequency and filter capacitances were obtained. This made it possible to express transfer functions through capacitances, at the same time as reducing the number of equations of the system. Examples of direct calculation of the 6th and 10th order PPFs were given.Conclusion. When converting TF of LPF, the frequencies of the realized AFR at both sides of the central BPF frequency are connected by certain relations. This fact makes it possible to eliminate the equations of the system that equate the coefficients of transfer function numerators, thereby reducing the total number of equations. Parameters, whose number exceeds that of the equations of the system, are selected arbitrarily from a number of standardized values. As a result, the accuracy of reproducing the realized frequency response is significantly improved.

Collective dynamics in liquid Si under high pressure above the melting line minimum

We report an ab initio simulation study of changes in structural and dynamic properties of liquid Si at 7 pressures ranging from 10.2 to 24.3 GPa along the isothermal line 1150 K, which is above the minimum of the melting line. The increase of pressure from 10.2 to 16 GPa causes strong reduction in the tetrahedral ordering of the closest neighbors. The diffusion coefficient shows a linear decay vs drop in atomic volume, that agrees with theoretical prediction for simple liquid metals, thus not showing any feature at the pressures corresponding to the different crystal phase boundaries. The Fourier-spectrum of the velocity autocorrelation function shows two-peak structure at pressures 20 of GPa and higher. These characteristic frequencies correspond well to the peak frequencies of the transverse current spectral function in the second pseudo-Brillouin zone. Two almost flat branches of short-wavelength transverse modes were observed at all the studied pressures. We discuss the pressure evolution of characteristic frequencies in the longitudinal and transverse branches of collective modes.

Calculation of Band-Pass Filters with Fixed Frequencies of Infinite Attenuation

Introduction. When calculating band-pass filters (BPF) with infinite attenuation frequencies using the frequency conversion method, the parameters of the prototype – an inverse or quasi-elliptic low-pass filter (LPF) – are recalculated into BPF parameters according to conventional formulas. Using the selected low-pass filter cutoff frequency and the Q-factor of the band-pass filter, one can select at their discretion only one infinite attenuation frequency (attenuation pole). In order to suppress a pair of concrete frequencies in the attenuation band, the synthesis of BPF should initially fix the frequencies of maximum attenuation and the central frequency of the filter. The reverse transition toward the frequency response parameters of a low-frequency prototype is carried out using frequency conversion formulas.Aim. To develop of a method for calculating band-pass filters with fixed attenuation poles.Materials and methods. Odd-order filters with an additional capacitor in the transverse branch of the П-link and an inductance in the longitudinal branch of the Т-link were used as low-frequency prototypes of the BPF with attenuation poles. Approximation of the frequency response of a low-frequency prototype (inverse or quasi-elliptical LPF) was performed by methods based on solving systems of nonlinear equations.Results. A realizable transfer function (TF) of an n-th order LPF with attenuation poles was written as the ratio of the product of binomials and a polynomial of power n with real coefficients. Systems of equations were derived to determine amplitude-frequency response coefficients with a given frequency of maximum attenuation interference for both types of filters. Analytical expressions for the TF of the low frequency prototypes of 3th and 5th orders were recorded through the capacitances of the BPF circuits tuned to the central and suppressed frequencies, thus allowing the desired capacitances to be directly calculated. The BPF inductances were determined by formulas expressing the dependences of the BPF central frequency on the circuits parameters, taking into account the relationships given in the article. An example of calculating a 10th order quasi-elliptic BPF was provided.Conclusion. The proposed method can be used to determine the BPF parameters directly, without an intermediate calculation and subsequent transformation of the LPF prototype parameters. The given analytical expressions for the frequency response of the П- and Т-shaped BPFs of the 6th and 10th orders make it possible to verify the performed calculations and to correct the frequency response using inductances, when replacing the calculated capacitance values with their standard values.

Deformation and strain limits for IPB-loaded high strength steel CHS joints

In this study, existing deformation limits are first re-examined to investigate if they can be rationally extended to high strength steel circular hollow section (CHS) joints that are subjected to in-plane bending (IPB) moment. It is pointed out that existing deformation limits, which have been developed and validated primarily for mild steel joints, need to be modified when high strength steels are involved. By noting that the ductility of IPB-loaded joints can be significantly reduced with the use of high strength steel, a new deformation limit is proposed which allows less deformation to less ductile high strength steel joints. The deformation limit, proposed in terms of joint rotation angle, is validated both numerically and experimentally. In addition, a recently proposed strain limit criterion is also discussed. To provide a guide for obtaining converged strain from finite element (FE) analysis, mesh sensitivity study is comprehensively conducted. It is shown that the element size required for the convergence of strain is substantially smaller than that required for obtaining satisfactory global response such as joint load-deformation relationship. By applying a systematic FE modeling strategy, numerical investigation is made to check the feasibility of the 5% strain limit criterion which has recently been advocated by the revised draft of ISO 14346. While the limiting principal strain of 5% is shown to be reasonable for CHS-to-CHS joints loaded by IPB, for longitudinal branch plate-to-CHS joints, a lower limiting strain appears more appropriate.

A new species of Elcanidae (Insecta: Orthoptera) from mid-Cretaceous Kachin amber

A new species of Elcanidae (Orthoptera: Elcanoidea), Panorpidium maculosum sp. nov., is described based on an exquisite specimen with both wing and body preserved from mid-Cretaceous Kachin amber. Wing venation suggests attribution to Panorpidium mainly on developed ScP (with six branches), three longitudinal branches between basal part of RP and CuA + CuPaα, and area between MP and anal edge of tegmen narrow. Body morphologies exhibit similarity to Burmelcana including metatibia with pairs of spine-like spurs in distal half, metatibia with three apical spurs, and metabasitarsus with a row of stout spines on ventral margin. Thereby the combined characters of Panorpidium maculosum sp. nov., including body structures and wing venation, indicate that Burmelcana and Panorpidium belong to one genus and Burmelcana is junior homonym name of Panorpidium. Additionally, the new species distinguishes from the species of Panorpidium mainly by metathoracic basitarsus with a row of stout spines on distal half and area between MP and anal edge of tegmen narrow with oblique and netted crossveins, and is erected as a new species. Our new find not only confirms subfamilial assignation of Burmelcana to the Elcaninae, but also provides evidence for incorporating Burmelcana longirostris Peñalver and Grimaldi 2010 to Panorpidium.

Waveguiding valley excitons in monolayer transition metal dichalcogenides by dielectric interfaces in the substrate

In monolayers of the semiconducting transition metal dichalcogenides, the electron-hole exchange interaction splits the exciton dispersion into a massive transverse branch, and a longitudinal branch that has very light or even zero mass depending on the form of screened Coulomb interaction. The group velocity of the longitudinal branch is sensitive to the strength of electron-hole exchange, which can be engineered through the dielectric environment. Here we show that dielectric patterning of the substrate can be exploited to realize waveguide of the exciton in the longitudinal branch in a homogeneous monolayer, leaving the massive transverse branch unaffected. At a lateral interface of different dielectric constant in the substrate, the transmission and reflection of exciton in the longitudinal branch obey the Snell-Descartes law of optical system, and total reflection can be exploited to realize excitonic waveguide using two parallel interfaces. The same dielectric pattern of the substrate appears to be completely transparent for the massive transverse branch exciton, which has no interface scattering. When the monolayer is placed on a one-dimensional dielectric superlattice, the dispersion of the longitudinal branch is strongly renormalized, and the wavefunctions exhibit one-dimensional features, confined to either the low-dielectric or high-dielectric regions. In contrast, the massive transverse branch excitons are not affected by the substrate dielectric pattern, exhibiting pristine properties as in a freestanding monolayer.

Методы увеличения уровня входной мощности в многоэлементных пленочных СВЧ аттенюаторах

The paper describes the design principles of multi-element broadband microwave attenuators of a high power level on film resistors. The proposed approaches make it possible to increase the input power level by several times or, at a constant input power, to significantly expand the ope¬rating frequency band. The studied attenuators with an insertion loss of 1-10 dB provide high-quality matching in the 0-2 GHz frequency band at an input power level of up to 500 W. These parameters are obtained by introducing quarter-wave sections of transmission lines with a certain wave imped-ance into the longitudinal and transverse branches of matched U-shaped and T-shaped dissipative structures.

Optimization of Lumped Parameter Models to Mitigate Numerical Oscillations in the Transient Responses of Short Transmission Lines

The Lumped Parameter Model (LPM) is a known approach to represent overhead transmission lines (TLs), especially when these elements comprehend a few tens of kilometers. LPMs employ a large number of cascaded π-circuits to compute accurately the transient responses. These responses contain numerical spurious oscillations (NSO) characterized by erroneous peaks which distort the transient responses, mainly their peak values. Two modified LPM topologies composed of damping resistances inserted along the longitudinal or transversal branches of the cascaded π-circuits offer significant mitigations in the NSO. In this paper, in an effort to have the maximum mitigation of the NSO and low distortion in the transient responses, two modified topologies with optimized damping resistances are proposed to represent short TLs. Results demonstrate expressive attenuation in the peaks of NSO which reflect good agreement in comparison with the responses computed by the Bergeron’s line model. The mitigation of the NSO is carried out directly in the time domain and it does not require either analog or digital filters.Furthermore, no frequency-to-time transformations are necessary in this procedure. These alternative topologies can be incorporated into any electromagnetic transient program to study switching operations in power systems.

Impact on periosteal vasculature after dual plating of the distal femur: a cadaveric study.

Objectives:Although dual plating of distal femur fractures has been described for injuries at risk of varus displacement, the vascular insult to the medial distal femur utilizing this technique is unknown. The aim of this study was to evaluate the perfusion of the medial distal femoral periosteal arteries after supplemental medial plating of the distal femur.Methods:Fifteen human fresh-frozen cadaveric femora were thawed and randomized to lateral locked plating alone or with supplemental medial plate fixation. Conventional submuscular medial plating was performed using a 12-hole small fragment plate and multiple cortical screws. The superficial femoral artery was injected with latex dye. Specimens were dissected. The patency of the medial distal femoral periosteal vessels was evaluated.Results:Four vessels were consistently observed traversing the distal medial femur: the transverse and descending (d-MMPA) branches of the medial metaphyseal periosteal artery, and the transverse and longitudinal branches of the descending geniculate artery. The anterior longitudinal arch (ALA) was present in 13 of 15 specimens and was fed by the d-MMPA. The median number of periosteal arteries occluded by the medial plate was 2 (6 out of 8 specimens). The d-MMPA was occluded in 6 of 8 medially plated femurs, resulting in a complete lack of perfusion of the ALA.Conclusions:Submuscular medial plating of the distal femur compressed the d-MMPA in the majority of specimens. This vessel gives rise to the ALA, which lacked perfusion in these specimens. This vascular insult could affect the healing of metaphyseal distal femur fractures treated with dual plating.

Load-tolerant external matching unit based on a wideband hybrid coupler for the ICRH system of DTT

In the first phase of the Divertor Tokamak Test Facility (DTT), the goal of coupling a RF power of 3 MW to the plasma will be reached with a single ICRH module constituted by 4 generators, 2 or 4 External Matching Units (EMU) and 2 antennas. The operation with high levels of RF power into ELMy H-mode plasmas requires a robust and reliable Load-Tolerant EMU. Currently the most appropriate solution, ensuring a VSWR at the generators under the safety threshold of 1.5:1, will be based on a Wideband 2-section coaxial Hybrid Coupler operating in the frequency range of 60−90 MHz. HFSS and CST-MS simulation software was used for the optimization of the characteristic impedances and lengths of the transversal and longitudinal branches aimed to achieve excellent performance (amplitude and phase balance at the output ports, and low reflection at the input port) over the entire frequency range. The analysis has been carried out for Zo = 50 Ω and 30 Ω coaxial transmission lines in terms of S-parameters and electric field. Several good solutions with an amplitude imbalance about ±0.25 dB and a return loss lower than −20 dB in a large part of the frequency range will be presented. Then a simulation of the overall (end-to-end) EMU (Wideband Hybrid Coupler with shifter, stub and service stub in each of the 2 output branches) exploiting a suitable circuital solver of Ansys Electronics tool of HFSS, has been implemented. The resilience of the EMU has been tested determining the VSWR in input and the amplitude balance at the outputs for a typical resistive and reactive loading variation occurring during ELMs at f = 75 MHz and compared with the results at 65 MHz and 85 MHz.

Hemivertebrectomy of L5 in Grade 2 Chondrosarcoma: Is a Single Posterior Approach with No Nerve Root Sacrifice Possible? A Case Report

En-bloc resection of spine tumors is difficult to achieve compared to extremities tumors for anatomical reason. Several surgical techniques have been described, such as combined multiple surgical approaches or an enlarged single posterior approach. These demanding strategies correlate with high rate of intraoperative/postoperative complications. The current case is about a patient treated with a single posterior-lateral surgical approach to perform hemivertebrectomy of L5 for a single grade 2 chondrosarcoma metastasis (WBB 2-5/b-c). Usually, L5 hemivertebrectomy requires a combined surgical approach to preserve L5 root. The final solution was to perform a T-shape skin incision: a longitudinal branch centered on the vertebral spine and a transverse branch on the iliac crest. This approach allowed osteotomy of the ipsilateral iliac crest, achieving sufficient view to preserve L5 root and vessels anteriorly; the same osteotomy was used to create a bone autograft to reconstruct the residual part of L5. Finally, cryotherapy was used in order to increase the adequacy of surgical margins. A L3-S1 arthrodesis is assembled to achieve stability of the system. Surgical time was 5 hours, no nerve roots have been sacrificed nor any other intraoperative complications occurred. This surgical technique had never been described before in literature.

Optical dispersion of valley-hybridised coherent excitons with momentum-dependent valley polarisation in monolayer semiconductor

2D excitons in transition-metal dichalcogenides (TMDCs) offer interesting effects related to the valley pseudo-spin degree of freedom and long-range exchange interactions, as well as the coupling with light states. Several theoretical predictions have claimed that the neutral exciton of TMDCs splits into a transversal and longitudinal exciton branch, with the longitudinal one, which is the upper branch, exhibiting an extraordinary strong dispersion in the meV range within the light cone. Historically, this was linked for semiconductor quantum wells to strong far-field optical dipole coupling, or strong electronic long-range exchange interactions. Recently, experiments utilizing Fourier-space spectroscopy have shown that the exciton (exciton–polariton) dispersion can indeed be measured for high-quality hexagonal-BN-encapsulated WSe2 monolayer samples and can confirm the energy scale. Here, the exciton fine-structure’s pseudo-spin and the valley polarisation are investigated as a function of the centre-of-mass-momentum and excitation-laser detuning. For quasi-resonant excitation, a strong dispersion featuring a pronounced momentum-dependent helicity is observed. By increasing the excitation energy step-wise towards and then above the electronic band gap and the B-exciton level, the dispersion and the helicity systematically decrease due to contributions of incoherent excitons and emission from plasma. The decline of the helicity with centre-of-mass momentum can be phenomenologically modelled by the Maialle–Silva–Sham mechanism using the exciton splitting as the source of an effective magnetic field. By contributing to a better understanding of valley decoherence effects and the role of hybridised states in the optoelectronic properties, polarisation-sensitive Fourier-space investigations can support the development of future ‘optical-valleytronic’ devices.