Terms Of Symmetry Research Articles

Analysis and Design of Configurable Rectifier With Compensated Near-Zero Impedance Angle for Megahertz Wireless Power Transfer

Adapting to wide load range variations is always one of the main goals pursued by megahertz (MHz) wireless power transfer (WPT) systems. For this, the nonlinear phenomenon of the rectifier has become a problem that must be solved. Compared with the method of optimizing the efficiency around the maximum power point in the traditional design, this paper proposes a global load optimization method. Meanwhile, a novel configurable compensated near-zero impedance angle rectifier (NIAR) is proposed to take full advantage of the global optimization method. The NIAR not only realizes the compression of a wide range of impedance angles, but also solves the classic problems of Class E rectifiers such as large stress, voltage asymmetry, and low real part of input impedance. The configurable design allows the system to adjust the rectifier unit according to the output index, thereby fully improving the coil efficiency, and providing a solution for the application of high-voltage and high-power MHz WPT systems in the future. To verify the effectiveness of the proposed NIAR and design method, a 60 W prototype was built, and a traditional full-wave rectifier was used for comparison. The results show that the proposed NIAR system exhibits better characteristics in terms of system efficiency, voltage stress, and symmetry.

Combined Use of Endoscopic Techniques and Virtual Surgical Planning for Intraoral Approach for Hemi-mandibular Resection and Reconstruction.

The study aimed to describe our experience in using endoscopic procedures to aid hemi-mandibular reconstruction with bone flaps through transoral approach. Five patients with huge benign mandibular tumors underwent transoral mandibulectomy and hemi-mandibular reconstruction, using endoscopy. Facial symmetry, occlusion, bone healing, and mandibular similarity were all evaluated postoperatively. The paired-samples t test was used to compare quantitative data, and a P value less than 0.05 was considered a significant difference. All five patients who received transoral mandibular surgery recovered in terms of TMJ functionality, facial symmetry, and aesthetic results. Endoscopy monitored and ensured that bone flaps were correctly connected and fixed. The accuracy of endoscopy-guided mandibular reconstruction was confirmed by quantitative examination for four cases, which revealed no statistically significant variations between postoperative CT analysis and preoperative virtual surgical planning data. Endoscopy-assisted virtual surgery may resolve concerns with transoral hemi-mandibular reconstruction and broaden indications for mini-invasive mandibular reconstruction. However, only patients with benign mandibular tumors were included in our study, so surgeons should be very cautious if applying this technique to malignant lesions or bony tumors invading soft tissues.

A new empirical formula for calculation of (n,3n) cross sections of heavy mass nuclei in the energy region 22–27.5 MeV

In this paper we want to study (n,3n) reactions using an empirical formula derived on the basis of the statistical model considering reaction Q-value dependence. This formula was obtained by taking into account the exponential dependence on asymmetry parameter (N−Z)/A for neutron-induced reactions in Levkovskii's empirical formula. In addition, the present formula depends also on incident energy En, reaction Q-value and symmetry term (N−Z)2/A. Herein, a new analysis of experimental data of (n,3n) reactions in the energy region 22–27.5 MeV was carried out for quick estimation of cross sections of the heavy mass isotopes of odd Z-even N nuclides in the region of A = 151 to 209. We observed a good agreement of the experimental cross section data with the calculations performed using the present empirical formula.

Three-dimensional Analysis of Maxillary Morphology in Infants with Unilateral Cleft Lip and Palate.

To three-dimensionally (3D) analyze the maxillary morphology of infants with unilateral cleft lip and palate (UCLP) and preliminarily classify the alveolar arch to assist in personalization of sequence therapy. Retrospective study. Patients with UCLP referred to outpatients' clinic. 84 nonsyndromic infants with complete UCLP were recruited (58 boys, 26 girls, mean age 29.48 days). Morphometric analysis was conducted on 3D maxillary models. Principal component analysis (PCA) and cluster analysis were combined to classify maxillary phenotypes preliminarily. The Wilcoxon Signed Rank test and the Kruskal-Wallis test were used to compare differences between variables. A P value less than .05 was considered statistically significant. The maxilla was divided into three types: narrow, homogenous and broad, accounting for 9.52%, 23.81% and 66.67% respectively. The alveolar cleft site (median value) was located in 61% of the total length of the alveolar arch. In the comparison of anterior and total alveolar lengths, the non-cleft side had longer alveolar bone than the affected side, a difference of approximately 2 mm. Pairwise comparisons of variables describing alveolar symmetry revealed significant differences in all subjects; whereas type C had poorer arch symmetry than types A and B, mainly in terms of anterior and overall symmetry. In infants with UCLP, the maxillary alveolar arch was inherently asymmetrical with partially bone missing (about 2 mm). Significant differences in alveolar bone morphology and symmetry exist between different types of infants, with individuals with broad clefts (type C, the largest proportion) having the worst maxillary development.

Historical Heritage Maintenance via Scan-to-BIM Approaches: A Case Study of the Lisbon Agricultural Exhibition Pavilion

Building Information Modeling (BIM) has emerged as a revolutionary tool in the domain of architectural conservation and documentation. When combined with terrestrial 3D laser scanning, it presents a powerful method to capture and represent the intricate details and nuances of historic structures. Such buildings, with their unique architectural lineage, often exude a geometric complexity unparalleled by standard designs. Consequently, the transition from scan data to a BIM framework, or the scan-to-BIM process, becomes intricate and time-intensive. Beyond the challenge of digital translation, the true essence of these historic buildings lies not only in their geometric form but also in understanding and preserving their design logic, formal composition rules, and primitive geometry. It then becomes imperative that the resulting model maintains fidelity in terms of proportion, shape, symmetry, and spatial rationale. Considering these challenges and potentials, this article delves into the process of digitalizing and BIM modeling of the Lisbon Agricultural Exhibition Pavilion located in Portugal. Our study proceeds in a tripartite structure: initiating with an in-depth terrestrial 3D laser scanning of the pavilion, followed by a comprehensive registration, processing, and alignment of the acquired scans, and culminating in a detailed BIM model using the industry-standard Revit 2020 software.

Changes in gait performances during walking with head movements in older adults with chronic neck pain.

Chronic neck pain (CNP) can lead to altered gait which is worse when combined with head movement. Gait parameters for indicating speed and symmetry have not been thoroughly investigated in older adults with CNP. This study aimed to compare gait performance in term of speed and symmetry in older adults with and without CNP during walking with head movement. Fifty young older adults, consisting of 36 healthy controls without neck pain (OLDs) and 14 older adults with CNP, participated in the study. Participants completed the Neck Disability Index and Activities-specific Balance Confidence Scale. The 10-Meter Walk Test (10MWT) was used to assess gait performance. Participants were instructed to walk at preferred speed under three different head movement patterns: no head movement (NM), horizontal head movement (HM), and vertical head movement (VM). The Inertial Measurement Unit was used to capture gait performance, and its software was used to analyze gait variables; gait speed, Locomotor Rehabilitation Index (LRI), gait asymmetry index, Phase Coordination Index (PCI). The CNP group reported moderate neck pain with mild disability in activities of daily living, and less balance confidence than the OLD group (p < 0.05). The CNP group showed significantly slower gait speed and lower LRI during walking with both the HM and VM (p < 0.05), which corresponded to lower stride length and cadence. The gait asymmetry index in the CNP group was significantly higher than the OLD group during walking with VM (p < 0.05), whereas the PCI was significantly higher than the OLD group during walking with both HM and VM (p < 0.05). Chronic neck pain affects both speed and symmetry when walking with head movement. Gait parameters in this study could be implemented to identify changes in speed and symmetry of gait in older adults with CNP who have mild disability and high physical functioning.

Comparison between one-jaw and two-jaw designs in virtual surgery planning for patients with class III malocclusion

Orthognathic surgery is highly effective for treating maxillomandibular discrepancies in patients with class III malocclusion. However, whether one- or two-jaw surgery should be selected remains controversial. Our study aimed to evaluate quantitative differences between one-jaw and two-jaw surgical designs.In total, 100 consecutive patients with skeletal class III malocclusion who underwent orthognathic surgery with preoperative three-dimensional simulation between August 2016 and November 2021 were recruited. Based on the same final occlusal setup, a two-jaw surgery design and two types of one-jaw design were created. In total, 400 image sets, including preoperative images and three types of surgical simulation, were measured and compared.The one-jaw mandibular setback design led to improvement in most cephalometric measurements and facial symmetry. Although the one-jaw maxillary advancement design improved the ANB angle and facial convexity, it induced maxillary protrusion and reduced facial symmetry. Compared with the other designs, the two-jaw design provided significantly closer cephalometric measurements to the normative values, better symmetry, and less occlusal cant.Overall, the two-jaw design provided a quantitatively better facial appearance in terms of symmetry, proportion, and profile. Although an optimal surgical design necessitates thorough preoperative evaluation and a shared decision-making process, two-jaw surgery can be considered for improving overall facial esthetics and harmony.

Vine Copula Model: Application to Chemical Elements in Water Samples

Copula can link the bivariate distribution function with marginal distribution functions without requiring specific information about the interdependence among random variables. There are several types of copulas, such as elliptical copulas, Archimedean copulas, and extreme value copulas. However, in multivariate modeling, each type of copula has limitations in modeling complex dependence structures in terms of symmetry and tail dependence properties. The class of vine copulas overcomes these limitations by constructing multivariate models using bivariate copulas in a tree-like structure. The bivariate copulas used in this study include the Clayton, Gumbel, Frank, Gaussian, and Student's t copula families. This study discusses the construction of vine copula models, parameter estimation, and their applications. The construction of vine copulas is done through the decomposition of conditional probability density functions and substituting bivariate copula density functions into the decomposition results. The data used in the study is the logarithm of the concentration of chemical elements in water samples in Colorado. The parameter estimation method used is pseudo-maximum likelihood with sequential estimation. Model selection is then performed using the Akaike information criterion (AIC) to determine the most suitable model. The results indicate that Caesium and Titanium have a dependency relationship with Scandium. Moreover, Scandium and Titanium exhibit the strongest dependence compared to other variable pairs.

Analysis of DNA Origami Nanostructures Using Capillary Electrophoresis.

DNA origami nanostructures are engineered nanomaterials (ENMs) that possess significant customizability, biocompatibility, and tunable structural and functional properties, making them potentially useful materials in fields, such as medicine, biocomputing, biomedical engineering, and measurement science. Despite the potential of DNA origami as a functional nanomaterial, a major barrier to its applicability is the difficulty associated with obtaining pure, well-folded structures. Therefore, rapid methods of analysis to ensure purity are needed to support the rapid development of this class of nanomaterials. Here, we present the development of capillary electrophoresis (CE) as an analytical tool for DNA origami. CE was investigated under both capillary zone electrophoresis (CZE) and capillary transient isotachophoresis (ctITP) modes. Optimization of both systems yielded baseline resolved separations of folded DNA origami nanostructures from excess staple strands. The ctITP separation mode demonstrated superior performance in terms of peak resolution (Rs = 2.05 ± 0.3), peak efficiency (N = 12,200 ± 230), and peak symmetry (As = 1.29 ± 0.032). The SYBR family dyes (Gold, Green I, and Green II) were investigated as highly efficient, noncovalent fluorophores for on-column labeling of DNA origami and detection using laser-induced fluorescence. Finally, ctITP analysis conditions were also applied to DNA origami nanostructures with different shapes and for the differentiation of DNA origami aggregates.

Palynological characterization of ornamental plants

Pollen grains are reproductive structures, which have a very resistant coating (exine outer wall and intine inner wall) and exhibit the main morphological components of palynological characterization. Ornamental plants are recognized for their plastic characteristics (flowers, leaves, perfume, fruits) and are generally grown in gardens. Aiming to carry out the palynological characterization of ornamental species, the following species were analyzed: Dietes bicolor (Steud. Klatt ex Sweet, 1866) (Iridaceae), Neomarica candida (Hassl. Sprague, 1928) (Iridaceae), Agapanthus inapertus (Beauverd, 1912) (Amaryllidaceae), Calceolaria tripartita (Ruiz &amp; Pav. 1798) (Calceolariaceae), Erythrina speciosa (Andrews, 1806) (Fabaceae), Begonia radicans (Vell. 1827) (Begoniaceae), Closed buds of the species were collected, which were conserved in acetic acid. The anthers were removed, macerated and acetolyzed. The pollen grains were mounted on microscopy slides, observed under light and scanning electron microscope, photographed and described in terms of unit, size, scope, polarity, symmetry, openings, shape and ornamentation. For the monocotyledons, the grains were in monads, elliptical in amb, heteropolar, large, with bilateral symmetry, monosulcate, with reticulated exine. For the eudicots, the grains were presented in monads, sub-circular/circular amb, isopolar, small/ medium, with radial symmetry, tri-tetracolporate, prolate/prolate-spheroidal shape, with reticulated /striated exine.

Bilateral fronto-orbital advancement combined with cranial vault release using a free-floating bone flap technique for nonsyndromic unilateral coronal synostosis.

The goals of operative treatment for unilateral coronal synostosis (UCS) are to improve appearance and allow unrestricted brain growth. However, for severe unilateral premature closure of the coronal suture, existing methods do not address the compression of the brain or expand the volume of the skull cavity. We report our retrospective experience with bilateral fronto-orbital advancement combined with cranial vault release using a free-floating bone flap (CVR + FFBF) technique and the resulting changes in the anterior cranial vault asymmetry index (ACVAI) and intracranial volume. Twenty patients with UCS who underwent bilateral fronto-orbital advancement combined with CVR + FFBF technique from April 2014 to May 2019 were included. Surgical efficacy was evaluated by the ACVAI and intracranial volume before the operation, 1 week after the operation, and at the last follow-up (average 19.8 months; range, 12 to 40 months). The measurement data are presented as the mean ± standard deviation and were statistically analyzed by t-test. The ACVAI was 9.07%±3.55% before the operation, 3.56%±3.42% 1 week after the operation, and 3.13%±2.41% at the last follow-up. The ACVAI 1 week after the operation was significantly lower than that before the operation (t=4.827, P<0.001). There was no significant difference between the ACVAI 1 week after the operation and at the last follow-up (t=0.660, P=0.517). The intracranial volume was 1,027.85±112.25 mL in patients before the operation and 1,131.92±161.71 mL in the normal control group, which was a statistically significant difference (t=2.364, P=0.023). The intracranial volume significantly increased 1 week after surgery: 1,081.62±111.10 mL (t=8.703, P<0.001), and this trend continued at the last follow-up (1,386.90±119.30 mL) similarly to the normal control group (1,438.22±89.28 mL). At the last follow-up, there was no significant difference between the two groups (t=1.540, P=0.132). For the treatment of UCS, bilateral fronto-orbital advancement combined with CVR + FFBF technique offers functional and cosmetic outcomes in terms of intracranial volume expansion and fronto-orbital symmetry.

Epitaxial-orientation-controlled magnetic anisotropy in the La0.67Sr0.33MnO3/SrTiO3 heterostructures

Magnetic anisotropy has significant importance in both designing high-efficiency magnetic devices and understanding noncollinear spin textures. Here, La0.67Sr0.33MnO3 layers are epitaxially fabricated on the (001)-, (110)-, and (111)-orientated SrTiO3 substrates to manipulate magnetic anisotropy. While the [11¯0] axis is the in-plane magnetic easy axis for the (001) La0.67Sr0.33MnO3 layer, it becomes the hard axis for the (110) and (111) samples. Interestingly, the (110) samples exhibit a great enhancement in magnetic anisotropy energy, reaching at 6.1 × 105 erg/cm3 that is 1–2 orders of magnitude higher than ones in (001) and (111) films. It is also noted that such improved magnetic anisotropy of (110) samples is maintained up to 30 nm. Those observations can be interpreted in terms of the orientation-modified orbital symmetry. While the energetically favored 3dx2−y2 orbital and degenerated eg orbitals drive the two-dimensional and bulk-like ferromagnetism in (001) and (111) La0.67Sr0.33MnO3 layers, respectively, the 3d3z2−r2 orbital provides the lowest orbital symmetry and results in the highest magnetic anisotropy energy in (110) samples. Meanwhile, this model can also explain the thickness-dependent Curie temperatures with different epitaxial orientations, deepening the understanding of the complex oxide heterostructures for magnetic modulations.

Structural, BFDH morphology, DSC, Infrared, and UV absorption studies of tetrachlorocobaltate and manganate NH3(CH2)nNH3MCl4 (M: Co, Mn, and n = 4, 5, 9) hybrid perovskite salts

Hybrid perovskite crystals NH3(CH2)nNH3MCl4 (M: Co, Mn, and n = 4, 5, 9), abbreviated CnMCl studied elswhere are investigated in terms of structural analysis, DSC, Infrared, and UV–visible spectroscopy properties. The structures of these salts are compared in terms of parametrs and space groups relationship symmetry. BFDH (Bravais-Fridel, Donnay–Harker) crystals morphologies are simulated using the units cell parametres and Laue symmetries of NH3(CH2)nNH3CoCl4 (n = 4, 9) of space group P-1 (Z = 2), NH3(CH2)5NH3MnCl4 considered in I212121 (Z = 4) and Imma (Z = 4) space groups, and NH3(CH2)9NH3CoCl4 (P21/c, Z = 4). DSC analyses showed that C4CoCl salt presents two continuous phase transitions at heating/cooling (321/320 K) and (309/295 K), while the C9CoCl salt did not present any phase transition between 310 and 400 K. The C5MnCl salt undergoes two continuous reversible phase transitions at heating/cooling (287/285 K) and (295/325 K); the thermal behavior of this salt is discussed in respect to the phase transition observed elswhere at 298 K. Infrared spectra of C4CoCl and C5MnCl compounds are discussed at different temperatures (80–352 K) regarding their DSC thermal behaviors. Far-Infrared spectra are discussed for CoCl42- and MnCl42- vibrational anions in CnCoCl (n = 4, 9) and CnMnCl (n = 5, 9) crystals based on theoretical group analyses. The UV–visible optical absorptions (300–1500 nm) revealed low bands gap for C4CoCl (1.80 eV) and C9CoCl (1.77 eV), suggesting these cobalt salts as good conductors for photovoltaic applications and solar cells, and good absorber materials with energies gap under 2 eV.

Phonon mixing in the charge density wave state of ScV6Sn6

Kagomé metals are widely recognized, versatile platforms for exploring topological properties, unconventional electronic correlations, magnetic frustration, and superconductivity. In the RV6Sn6 family of materials (R = Sc, Y, Lu), ScV6Sn6 hosts an unusual charge density wave ground state as well as structural similarities with the AV3Sb5 system (A = K, Cs, Rb). In this work, we combine Raman scattering spectroscopy with first-principles lattice dynamics calculations to reveal phonon mixing processes in the charge density wave state of ScV6Sn6. In the low temperature phase, we find at least four new peaks in the vicinity of the V-containing totally symmetric mode near 240 cm−1 suggesting that the density wave acts to mix modes of P6/mmm and Rbar{3}m symmetry - a result that we quantify by projecting phonons of the high symmetry state onto those of the lower symmetry structure. We also test the stability of the short-range ordered density wave state under compression and propose that both physical and chemical pressure quench the effect. We discuss these findings in terms of symmetry and the structure-property trends that can be unraveled in this system.

Pauli topological subsystem codes from Abelian anyon theories

We construct Pauli topological subsystem codes characterized by arbitrary two-dimensional Abelian anyon theories–this includes anyon theories with degenerate braiding relations and those without a gapped boundary to the vacuum. Our work both extends the classification of two-dimensional Pauli topological subsystem codes to systems of composite-dimensional qudits and establishes that the classification is at least as rich as that of Abelian anyon theories. We exemplify the construction with topological subsystem codes defined on four-dimensional qudits based on the Z4(1) anyon theory with degenerate braiding relations and the chiral semion theory–both of which cannot be captured by topological stabilizer codes. The construction proceeds by "gauging out" certain anyon types of a topological stabilizer code. This amounts to defining a gauge group generated by the stabilizer group of the topological stabilizer code and a set of anyonic string operators for the anyon types that are gauged out. The resulting topological subsystem code is characterized by an anyon theory containing a proper subset of the anyons of the topological stabilizer code. We thereby show that every Abelian anyon theory is a subtheory of a stack of toric codes and a certain family of twisted quantum doubles that generalize the double semion anyon theory. We further prove a number of general statements about the logical operators of translation invariant topological subsystem codes and define their associated anyon theories in terms of higher-form symmetries.

A Goldstone theorem for continuous non-invertible symmetries

We study systems with an Adler-Bell-Jackiw anomaly in terms of non-invertible symmetry. We present a new kind of non-invertible charge defect where a key role is played by a local current operator localized on the defect. The charge defects are now labeled by elements of a continuous (1). We use this construction to prove an analogue of Goldstone’s theorem for such non-invertible symmetries. We comment on possible applications to string theory.

Vector wave solutions in electrodynamics: the Heaviside-Larmor symmetry and tiered potential invariance

Abstract The tiered symmetric structure of the electromagnetic equations, in particular the Heaviside Larmor (HL) symmetry, is used to obtain vector wave solutions of the wave equation obtained from Maxwell's equations. In this HL vector solutions procedure (HL-VS), the seed vector need not be constant but must satisfy an inhomogeneous Helmholtz equation. This seed can be used either to obtain the polarization basis in a given coordinate system or a particular polarization state. The spherical vector waves (SVW) basis is economically derived retaining the physical meaning throughout the procedure. Examples of low order modes are expounded. The cylindrical vector wave basis is also derived and particular polarization states are compared with previous results. Plane waves are used to elucidate the HL symmetry terms and their controlled manipulation in order to tailor specific structured light states. The angular momentum of plane waves with elliptical polarization is obtained. The controversy as to whether circularly polarized plane waves carry angular momentum is answered in the affirmative.

A new freshwater gomphonemoid diatom genus from India, with the description of a new species from the Eastern Ghats

ABSTRACT We present light and SEM observations of a new astigmate gomphonemoid diatom from the Eastern Ghats of India. This species, and a closely allied one from the Western Ghats that has a stigma, are similar to other members of the Gomphonemataceae in terms of symmetry and certain valve features. They differ, however, in having groups of differentiated pore fields at both apices. At the headpole, the area bearing the groups of pores is flattened and positioned on the valve mantle, and is not easily seen in light microscopy. For these species we propose the genus Indiconema gen. nov. within the Gomphonemataceae. We evaluate the phylogenetic position of this group and relationships within the family based on valve and girdle band features, which suggest that the new genus is sister to Afrocymbella, a genus apparently endemic to Africa. We compare this basal phylogenetic position with other groups of organisms also found in the Western and Eastern Ghats of India, as well as to fossil taxa in the Gomphonemataceae. The sister taxon relationship with a genus known only from Africa supports a close relationship of the floras of the two regions.

Assessing human worker performance by pattern mining of Kinect sensor skeleton data

The human worker is an in-disposable factor in manufacturing processes. Traditional observation methods to assess their performance is time-consuming and expert-dependent, while it is still impossible to diagnose the detailed movement trajectory with the naked eye. Industry 4.0 technologies can innovate that process with smart sensors paired with data mining techniques for automated operation and develop a database of frequent movements for corporate reference and improvement. This paper proposes an approach to automatically assess worker performance with skeleton data by applying pattern mining methods and supervised learning algorithms. A use case is performed on an electrical assembly line to validate the approach, with the skeleton data collected by Kinect sensor v2. By using supervised learning, the movements of workers in each workstation can be segmented, and the line performance can be assessed. The work movement motifs can be recognized with pattern mining. The mined results can be used to further improve the production processes in terms of work procedures, movement symmetry, body utilization, and other ergonomics factors for both short and long-term human resource development. The promising result motivates further utilization of easy-to-adopt technology in Industry 5.0, which facilitates human-centric data-driven improvements.

Heteroatom-Based Diradical(oid)s.

Heteroatom-centered diradical(oid)s have been in the focus of molecular main group chemistry for nearly 30 years. During this time, the diradical concept has evolved and the focus has shifted to the rational design of diradical(oid)s for specific applications. This review article begins with some important theoretical considerations of the diradical and tetraradical concept. Based on these theoretical considerations, the design of diradical(oid)s in terms of ligand choice, steric, symmetry, electronic situation, element choice, and reactivity is highlighted with examples. In particular, heteroatom-centered diradical reactions are discussed and compared with closed-shell reactions such as pericyclic additions. The comparison between closed-shell reactivity, which proceeds in a concerted manner, and open-shell reactivity, which proceeds in a stepwise fashion, along with considerations of diradical(oid) design, provides a rational understanding of this interesting and unusual class of compounds. The application of diradical(oid)s, for example in small molecule activation or as molecular switches, is also highlighted. The final part of this review begins with application-related details of the spectroscopy of diradical(oid)s, followed by an update of the heteroatom-centered diradical(oid)s and tetraradical(oid)s published in the last 10 years since 2013.