Additional Modes Research Articles

Stereoselective Synthesis of 4‐Hydroxy‐1‐Silyl‐1‐Allenylboranes and Access to 2‐Silylethynyl‐1,3‐Diols

AbstractThe highly stereoselective gem‐silylboration of chiral 2‐substituted 1‐ethynylepoxides is reported herein. The reaction involves first the deprotonation of the epoxides in the acetylenic position followed by transmetallation with Et3SiBpin. The transient silylborane ate‐complexes generated undergo the stereoselective 1,2‐migration of the Et3Si‐group to the sp‐hybridized terminus carbon of the ethynyl‐moiety in a stereospecific anti‐addition. The moisture‐sensitive and thermally unstable 4‐hydroxy‐1‐triethylsilyl‐1‐allenyl(pinacolato)boranes thus obtained react with aldehydes through an SE2’‐mode of addition, affording highly functionalized 2‐triethysilylethynyl‐1,3‐diols with a good diastereoselectivity which is rationalized by a Yamamoto‐Houk type transition state model.

Developing a Robust Process for Design Margin Calculation Through Modal Scaling and Harmonic Analysis of Engine Mounted After Treatment System

The last few years have seen an increase in the complexity of emission standards. This has caused OEMs to start using Exhaust Gas Processors (EGP) or Exhaust After Treatment Systems (EATS)in complex integration. These systems are usually mounted on vehicle chassis or engine body with the help of mounting straps or brackets. The arrangement of the system leads to road loads and/or engine vibrations being transferred and causing damage to its components. New BS VI engines need some AT (After treatment) components to be mounted directly on the engine and others to chassis. The components that are directly mounted on engine are called close couple AT system which are subjected to engine harmonic vibrations which falls under forced vibration criteria. Most of the AT system are subjected to random vibrations and industry has a well-defined procedure to address the problem, but for harmonic vibrations there is no specific approach. In order to optimize the structural durability of close couple AT system against HCF (high cycle fatigue) fatigue harmonic vibration, there is a need for well-defined test analysis correlation procedure. The objective of this work is defining and documenting a robust process for design margin through calculation modal scaling and harmonic analysis of close couple AT system through test analysis correlation activity. Analytical, numerical and testing data were compared and conclusions are drawn. More case studies can be added to this work in order to validate the test analysis correlation activity and boost the degree of confidence. Future study may include recording additional failure modes in addition to the harmonic HCF failure mode.

Activity of amorolfine or ciclopirox in combination with terbinafine against pathogenic fungi in onychomycosis-Results of an invitro investigation.

Onychomycoses are difficult-to-treat fungal infections with high relapse rates. Combining oral and topical antifungal drugs is associated with higher success rates. Additive or synergistic modes of action are expected to enhance treatment success rates. Investigation of the combined effects of antifungal drugs invitro with different modes of action and application on clinical isolates from mycotic nails. Isolates of Trichophyton rubrum, Trichophyton interdigitale and Scopulariopsis brevicaulis were collected from infected toenail specimens of patients with onychomycosis. Susceptibility testing was performed in 96-well polystyrene plates using a standard stepwise microdilution protocol. Additive or synergistic activity at varying concentrations was investigated by the checkerboard method. Combining terbinafine with amorolfine tended to be more effective than terbinafine in conjunction with ciclopirox. In most combinations, additive effects were observed. Synergy was detected in combinations with involving amorolfine in S. brevicaulis. These additive and synergistic interactions indicate that combined therapy with topical amorolfine and oral terbinafine is justified. Sublimation of amorolfine (and terbinafine) may enhance the penetration in and through the nail plate, and support treatment efficacy. These invitro results support the notion that combining oral terbinafine and topical amorolfine is beneficial to patients with onychomycosis, particularly if the pathogen is a non-dermatophyte fungus such as S. brevicaulis.

Typing Fluencies of 12–13-Year-Old Students with Dyslexia and Peers with Typical Development

Several factors can impede the writing process of students with dyslexia. One recommended adjustment to help them overcome these writing challenges is the use of personal computers for writing. The research underscores the significance of effective keyboarding skills in optimizing the benefits of computer-based writing for these students, with touch-typing being the frequently recommended typing technique. Although research findings point to various reasons that indicate that students with dyslexia may face difficulties in developing fluent touch-typing skills, we found a lack of research in this area. In order to address this gap, in our study we examined and compared 12–13-year-old Slovenian students with dyslexia and their typically developing peers in terms of their existing, self-taught typing technique fluency, the fluency achieved in learning touch-typing and the fluency achieved in learning a simple finger-typing task. We found a significant difference between handwritten and self-taught typing fluency of students with dyslexia, with handwriting being a more fluent form of transcription. The results of students with dyslexia are significantly lower from their peers in handwriting fluency, self-taught typing fluency, touch-typing fluency and simple finger-typing task fluency. However, the learning trends for touch-typing and the simple finger-typing task do not differ between the groups of students. We comment on the differences found and make suggestions when considering typing as an additional or alternative transcription mode.

Dipole symmetries from the topology of the phase space and the constraints on the low-energy spectrum

We demonstrate the general existence of a local dipole conservation law in bosonic field theory. The scalar charge density arises from the symplectic form of the system, whereas the tensor current descends from its stress tensor. The algebra of spatial translations becomes centrally extended in presence of field configurations with a finite nonzero charge. Furthermore, when the symplectic form is closed but not exact, the system may, surprisingly, lack a well-defined momentum density. This leads to a theorem for the presence of additional light modes in the system whenever the short-distance physics is governed by a translationally invariant local field theory. We also illustrate this mechanism for axion electrodynamics as an example of a system with Nambu-Goldstone modes of higher-form symmetries.

Magnetic anisotropy and ferromagnetic resonance in inhomogeneous demagnetizing fields near edges of thin magnetic films

Using local ferromagnetic resonance spectroscopy, we have studied the magnetic properties near edges of thin tangentially magnetized permalloy films, in which a well-defined uniaxial magnetic anisotropy was induced perpendicular to one of the edges. In the experiment, two samples with thicknesses of 90 and 300 nm and with slightly different compositions were examined. To explain the magnetization dynamics near edges, we propose a simple yet effective model of a film in the form of a rectangular prism, which yields the modified Kittel formula for the resonance frequency. In this formula, the locally averaged distance-dependent demagnetizing field that emerges near the edges is included as an additional uniaxial anisotropy term. The measurements reveal that at a certain distance from the edge, the resulting (apparent) anisotropy, determined from the angular dependencies of the resonance field, almost vanishes. Moreover, its easy axis reorients to become parallel to the edge. The model predictions agree well with these results, proving that the main resonance mode behavior near the film edges can be accurately described by introducing additional effective uniaxial anisotropy, provided the measuring area is relatively large. However, for the thick (300 nm) sample, additional precession modes are also observed. These modes distort the angular dependence of the main mode, thus demonstrating the limitations of the model.

Insights into multiple deformation mechanisms induced ultrahigh impact toughness of high-purity titanium

High-purity titanium exhibited ultrahigh impact toughness about 312.5 J/cm2 in this study. To uncover the underlying deformation mechanisms for the ultrahigh impact toughness, postmortem analysis of the deformation microstructure was performed using the electron back-scatter diffraction (EBSD) and transmission electron microscope (TEM) techniques. The results indicate that multiple deformation behaviors occurred in high-purity titanium. Dense dislocation activities were activated in the regions near and away from the crack tip. The average GND densities of the deformation microstructure (1.71 × 1015/m2 and 1.21×1015/m2, respectively) were much larger than that (0.06×1015/m2) of the initial specimen. Moreover, plentiful deformation twinning and detwinning behaviors were observed in the deformation microstructure which significantly contributed to plastic deformation and high impact toughness. Moreover, deformation induced α-Ti → FCC Ti transformation was also activated which played as an additional deformation mode in the high-purity titanium. Multiple deformation behaviors including dislocation activities, deformation twinning/detwinning behaviors and deformation induced α-Ti → FCC Ti transformation, were responsible for the ultrahigh impact toughness of high-purity titanium.

Asymmetrical Cross-Polarization Coupling in a Whispering-Gallery Microresonator

Cross-polarization coupling between transverse electric (TE) and transverse magnetic (TM) whispering-gallery modes in an optical microresonator produces effects such as coupled-mode induced transparency (CMIT). The detailed analytical theory of this coupling indicates that the TE-to-TM and TM-to-TE couplings may have different strengths. Using an experimental setup centered around a hollow bottle resonator and polarization-sensitive throughput detection, that had been used in previous CMIT experiments, this asymmetry was confirmed and studied. By fitting the throughput spectra of both polarizations to the numerical output of a basic model, the asymmetry parameter defined as the ratio of the coupling amplitudes was determined from the output power in the polarization orthogonal to that of the input. The results of many experiments give a range for this ratio, roughly from 0.2 to 4, that agrees with the range predicted by the detailed theory. An analytical approximation of this ratio shows that the main reason for the asymmetry is a difference in the axial orders of the coupled modes. In some experimental cases, the orthogonal output is not well fitted by the model that assumes a single mode of each polarization, and we demonstrate that this fitting discrepancy can be the result of additional mode interactions.

On the degrees of freedom of R2 gravity in flat spacetime

We study the degrees of freedom of R2 gravity in flat spacetime with two approaches. By rewriting the theory a la Stueckelberg, and implementing Lorentz-like gauges to the metric perturbations, we confirm that the pure theory propagates one scalar degree of freedom, while the full theory contains two tensor modes in addition. We then consider the degrees of freedom by directly examining the metric perturbations. We show that the degrees of freedom of the full theory match with those obtained with the manifestly covariant approach. In contrast, we find that the pure R2 gravity has no degrees of freedom. We show that a similar discrepancy between the two approaches appears also in a theory dual to the three-form, and appears due to the Lorentz-like gauges, which lead to the fictitious modes even after the residual gauge redundancy has been taken into account. At first sight, this implies a discontinuity between the full theory and the pure case. By studying the first-order corrections of the full R2 gravity beyond the linear regime, we show that at high-energies, both scalar and tensor degrees of freedom become strongly coupled. This implies that the apparent discontinuity of pure and full R2 gravity is just an artefact of the perturbation theory, and further supports the absence of degrees of freedom in the pure R2 gravity.

Phase transitions in HfO2 probed by first-principles computations

Ever since ferroelectricity was discovered in HfO2, the question of its origin remains controversial. Here, we probe this question using a combination of Landau theory of phase transitions and first-principles computations. In such an approach, the energy landscape associated with the phase transition between cubic and different experimentally demonstrated phases of HfO2 (tetragonal, monoclinic, orthorhombic Pbca, orthorhombic Pnma, and orthorhombic Pca21) is explored using density functional theory calculations. Computations revealed that stabilization of all but orthorhombic Pbca phase is driven by a single unstable zone-boundary antipolar mode X2−. When coupled with zone-center modes (Γ1+ and Γ3+), it stabilizes the tetragonal phase. Coupling with four additional modes (Γ5+, X3−, X5−, X5+) results in the monoclinic phase, which is the ground state of the material. If, however, Γ5+ mode is replaced with Γ4− mode, orthorhombic polar phase Pca21 is stabilized. The application of this framework to examine the effect of electric field on the ferroelectric phase of hafnia reveals that the field of 5 MV/cm is capable of stabilizing ferroelectric phase over the monoclinic one at 0 K.

Tuning of magnetosplamon coupling between graphene scatterers for the optimal design of adjustable metasurfaces

The resonance characteristics of magnetically-biased graphene micro-scatterers are thoroughly investigated in the present work using both eigenvalue and full-wave solvers. Initially, the graphene surface conductivity is presented in a tensor form due to the application of a magnetostatic bias field, which is perpendicular to the material’s surface. Then, the simple case of a graphene disk scatterer is examined, and a properly modified eigenvalue formulation is utilized to extract the plasmonic fundamental frequencies. The validity of the modal analysis is verified via a full-wave analysis that involves a plane-wave propagation and the extraction of the subsequent absorption cross-section utilizing the Finite-Difference Time-Domain method. Additionally, the dependence of a single disk scatterer resonances with the magnetostatic bias is evaluated, highlighting that as the bias field is increased, every edge mode degenerates into two sub-modes with an augmented difference between the resonant frequencies. Finally, the plasmonic coupling between adjacent scatterers is studied considering a periodic arrangement, similar to a metasurface, indicating the additional coupling modes as well as the adjustability of the properties with multiple degrees of freedom.

Unveiling the intricate symphony of nonlinear pulsation mode interactions in high-amplitudeδScuti stars

Information on the interiors of stars can be gleaned from their pulsations. Pulsation modes, which are determined by the internal state and structure of a star, are typically considered stable over short timescales. These independent pulsation modes have been used in asteroseismology to determine the interior structures of stars. Here, we report the discovery of peculiar pulsation mode interactions in the high-amplitudeδScuti star KIC 6382916 (J19480292+4146558) that challenge the reliability of independent pulsation modes as indicators of a star’s internal structure. Through analysis of archival data, we find distinct variations in the amplitudes and frequencies of three independent pulsation modes and their harmonics and combinations over approximately 20 days. These variations can reach amplitudes of about 140% and frequency variations of about 12%. Correlation analysis of amplitude and frequency variations reveal additional pulsation mode interaction details and patterns. Notably, our findings regarding the phenomena related to the harmonics of independent pulsation modes challenge the traditional understanding in this area. These discoveries serve as cornerstones for future research and advance nonlinear asteroseismology.

Modelling plasmonic nanoparticles: Unveiling the optical torque potential with a dynamic driven damped harmonic oscillator model and width dependent effects

Linearly polarised light induces torque on anisotropic plasmonic nanoparticles, which allows for the manipulation of their orientation. In this study, we calculate the torque induced on a plasmonic nanocuboid by modelling the surface plasmon resonance (SPR) as a driven damped harmonic oscillator. Using numerical simulations, we demonstrate the model’s accuracy in predicting the torque induced for narrow nanocuboids. We also investigate the effects of varying the nanocuboid’s width on the torque and demonstrate that the torque behaviour exhibits drastic changes, with the formation and modification of additional modes, particularly at the transverse SPR wavelength. As the torque arises from the movement of charges, we utilize charge distribution profiles to explain this shift in torque behaviour.

A preliminary characterization of cannabis oil use and vaporization among individuals who use for medical purposes: A pilot study.

Little is known about the naturalistic use of cannabis oil vaporization, a high-potency product with the ability to be administered discreetly. This pilot study evaluated the feasibility of utilizing a "smart" vaporizer and application to assess the timing, frequency, socioenvironmental factors, and substance use involved in cannabis oil vaporization. Adults with a medical cannabis registration card were recruited from a dispensary in Rhode Island and completed a 2-week study monitoring period using the Gram1 vaporizer, followed by a poststudy qualitative interview. The sample included nine adults who were predominantly male (89%), 100% White, and 100% non-Hispanic. The Gram1 collected topographical vaping data, and the cellphone application utilized ecological momentary assessment (EMA) to assess socioenvironmental factors and other substance use. Qualitative interview data were coded, and illustrative quotations were selected to support quantitative findings. A total of 224 vaping sessions were recorded reflecting 76.4% of the study monitoring period. There was an average of 1.79 vaping sessions per day across all days. Participants took 8.76 puffs on average (SD = 8.23) per vaping session, and the session lasted 2.59 min on average (SD = 4.19). Regular vaporization was exhibited across days of the week and hours of the day. EMA reports indicated that smoking cannabis flower was the most common additional mode of cannabis administration. This study utilized a naturalistic design with novel topographical data and EMA to characterize cannabis oil vaporization. These findings establish the feasibility of collecting objective, momentary data to better understand use behaviors which are critical to informing safe consumption. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The Influence of Pedestrian Characteristic on Pedestrian Speed in Urban Area: A Case Study at Jalan Tuanku Abdul Rahman, Kuala Lumpur

Short-distance walking, alone or with additional modes, is efficient. Well-established public transport may increase the number of pedestrians since they prefer walking to work, travel, and shop because cities are connected by activities and locations. However, pedestrian-friendly paths and public transport in Malaysia have received little attention. Large-scale facilities like stadiums, movie theatres, and amusement parks are driving the need for pedestrian facilities. Thus, this study aims to examines the pedestrian characteristic at Jalan Tuanku Abdul Rahman, Kuala Lumpur. To discover significant elements, pedestrian behaviour on sidewalks at the indicated location was quantitatively investigated, taking into account general pedestrian characteristics that affect walking speed, such as age, gender, and trip companion. Using a video camera, pedestrian variables like age, gender, and trip companion were calculated for volume, speed, flow, density, and space during weekday and weekend peak hours. Extracted data were then analysed by using SPSS as a statistical software and the Highway Capacity Manual (HCM 2010) was used to classify pedestrian level of services (LOS). Age, gender, and companionship substantially determine the pedestrian flow and the study’s LOS for pedestrian characteristics ranges from D to E, indicating that Jalan Tuanku Abdul Rahman’s sidewalk relationship varies. This research strongly recommends a dedicated walkway to increase pedestrian space and improve services along Jalan Tuanku Abdul Rahman, Kuala Lumpur. This study will also serve as a guideline to the transport operator into improving the future of pedestrian walkway design facilities.

Precision Higgs width and couplings with a high energy muon collider

The interpretation of Higgs data is typically based on different assumptions about whether there can be additional decay modes of the Higgs or if any couplings can be bounded by theoretical arguments. Going beyond these assumptions requires either a precision measurement of the Higgs width or an absolute measurement of a coupling to eliminate a flat direction in precision fits that occurs when ghVV/ghVVSM\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\left|{g}_{hVV}/{g}_{hVV}^{SM}\\right| $$\\end{document} > 1, where V = W±, Z. In this paper we explore how well a high energy muon collider can test Higgs physics without having to make assumptions on the total width of the Higgs. In particular, we investigate off-shell methods for Higgs production used at the LHC and searches for invisible decays of the Higgs to see how powerful they are at a muon collider. We then investigate the theoretical requirements on a model which can exist in such a flat direction. Combining expected Higgs precision with other constraints, the most dangerous flat direction is described by generalized Georgi-Machacek models. We find that by combining direct searches with Higgs precision, a high energy muon collider can robustly test single Higgs precision down to the O.1%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{O}\\left(.1\\%\\right) $$\\end{document} level without having to assume SM Higgs decays. Furthermore, it allows one to bound new contributions to the width at the sub-percent level as well. Finally, we comment on how even in this difficult flat direction for Higgs precision, a muon collider can robustly test or discover new physics in multiple ways. Expanding beyond simple coupling modifiers/EFTs, there is a large region of parameter space that muon colliders can explore for EWSB that is not probed with only standard Higgs precision observables.

Single-wideband and dual-band bandpass filters based on compact quadruple-mode resonator

A stub-loaded U-shaped microstrip resonator (U-SLR) exciting two odd-modes and two even-modes and its applications to single-wideband and dual-band bandpass filter (DB-BPF) are introduced. The parallel-coupled lines (PCLs) at input/output (I/O) ports can provide a wideband response by exciting two additional modes in the passband, so-called PCLs modes. In addition to the transmission poles (TPs) in the passband, two transmission zeros (TZs) in the lower and upper stopbands can be created by the loaded stubs. A compact size, high-selectivity, and low insertion loss WB-BPF is designed, fabricated, and tested. Moreover, a compact and low loss DB-BPF with closely spaced passbands is designed and tested. TZ-shifting method is used to design a DB-BPF by splitting the wideband. To achieve this, it is sufficient to change the length of only one of the loaded stubs. The calculated, simulated and measured frequency responses for both single-wideband and DB-BPFs are in very good agreement.

Eigenmodes of 1-kink skyrmions in cylindrical magnetic discs

The stability and resonance spectra associated with a domain wall skyrmion embedded within a Néel skyrmion, forming a 1-kink skyrmion, has been studied using micromagnetic simulations. We show that the 1-kink skyrmion is stable over a wide range of fields at moderate strengths of the Dzyaloshinskii-Moriya interaction. By exciting these structures with a broadband magnetic field excitation, we find complex resonance behavior deviating from that of a pure Néel skyrmion. For out-of-plane excitations, the 1-kink skyrmion demonstrates an additional mode relative to that of the Néel skyrmion at reduced amplitude. These consist of low frequency and high frequency modes associated with both a breathing mode and an oscillation of the embedded domain wall skyrmion. Following an in-plane excitation, both Néel and 1-kink skyrmions exhibit a counterclockwise rotational mode with similar frequencies, as well as a higher frequency mode associated with the interaction of the structure with the ferromagnetic background state. These results may help pave the way for exploration of more complex spin structures for magnetic-based microwave devices.

Ultra-broadband directional thermal emission

Abstract Directional control of thermal emission over its broad wavelength range is a fundamental challenge. Gradient epsilon-near-zero (ENZ) material supporting Berreman mode has been proposed as a promising approach. However, the bandwidth is still inherently limited due to the availability of ENZ materials covering a broad bandwidth and additional undesired omnidirectional modes in multilayer stacking with increased thickness. Here, we show that broadband directional thermal emission can be realized beyond the previously considered epsilon-near-zero and Berreman mode region. We then establish a universal approach based on effective medium theory to realizing ultra-broadband directional thermal emitter. We numerically demonstrate strong (emissivity >0.8) directional (80 ± 5°) thermal emission covering the entire thermal emission wavelength range (5–30 μm) by using only two materials. This approach offers a new capability for manipulating thermal emission with potential applications in high-efficiency information encryption, energy collection and utilization, thermal camouflaging, and infrared detection.

High Speed Dual‐Band Photodetector for Dual‐Channel Optical Communications in Wavelength Division Multiplexing and Security Enhancement

AbstractThe forthcoming wireless networks must integrate to a high density of end‐user devices while ensuring a superior quality of service. It is imperative to devise solutions that reduce the density of wireless access points and associated costs, while simultaneously ensuring security and privacy throughout propagation. Herein, a novel dual‐band photodetector with high selective responsivities in distinct visible and near‐infrared (NIR) band is developed as an optical signal receiver. The receiver has an unprecedented fast switch speed > 500 kHz between different operation modes. Leveraging this fast switch speed, a high‐speed Multiple‐Input‐Single‐Output (MISO) system is developed, fusing spectrum resources from visible to infrared bands. The system achieves a data rate of 600 Kbps in the visible channel and 500 Kbps in the NIR channel, with a sum rate of 1.1 Mbps. This is the highest single‐channel data rate and sum rate among reported dual‐band photodetectors. Additionally, two previously overlooked mechanisms, the Subtraction and Addition modes, are studied in detail. The four operation modes are developed to establish a novel physical encryption method in terms of arithmetic relation. The dual‐channel coupled link can support a data rate of 200 Kbps, significantly enhancing communication security.