Ring Structure Research Articles

On von Neumann Regularity of Commutators

We study the structure of rings which satisfy the von Neumann regularity of commutators, and call a ring [Formula: see text] C-regular if [Formula: see text] for all [Formula: see text], [Formula: see text] in [Formula: see text]. For a C-regular ring [Formula: see text], we prove [Formula: see text], where [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] are the Jacobson radical, upper nilradical, Wedderburn radical, and center of a given ring [Formula: see text], respectively, and [Formula: see text] denotes the polynomial ring with a set [Formula: see text] of commuting indeterminates over [Formula: see text]; we also prove that [Formula: see text] is semiprime if and only if the right (left) singular ideal of [Formula: see text] is zero. We provide methods to construct C-regular rings which are neither commutative nor von Neumann regular, from any given ring. Moreover, for a C-regular ring [Formula: see text], the following are proved to be equivalent: (i) [Formula: see text] is Abelian; (ii) every prime factor ring of [Formula: see text] is a duo domain; (iii) [Formula: see text] is quasi-duo; and (iv) [Formula: see text] is reduced.

Highly sensitive and easy-to-attach wearable sensor for measuring finger force based on curvature changes in an ellipse-shaped finger ring

Abstract Technologies aimed at digitizing worker actions to enhance human labor tasks and mitigate accidents and disabilities have garnered significant attention. This study focuses on monitoring the force exerted by the fingers and developing a wearable fingertip force sensor based on a simple elliptical ring structure in conjunction with a commercially available resistive bend sensor. Resembling a ring accessory, the sensor is easy to attach and detach, and exhibits high sensitivity, with a resistance change of approximately 9% for a fingertip load of 1N. Furthermore, to mitigate crosstalk during finger flexion, we propose a combined configuration employing this ring-shaped sensor alongside another sensor designed for measuring and rectifying finger flexion angles. Additionally, we introduce an empirically derived fitting function and a straightforward calibration procedure to extract the function’s parameters. The results indicate that the proposed system achieves an average RMS error of 0.53 N for force estimations of approximately 5 N, even amidst finger bending and postural changes.

Highly Stable Heating Fibers of Ti3C2Tx MXene and Polyacrylonitrile via Synergistic Thermal Annealing.

Nanohybrid assemblies provide an effective platform for integrating the intrinsic properties of individual components into microscale fibers. In this study, a novel approach for creating mechanically and environmentally stable MXene fibers through the synergistic assembly of MXene and polyacrylonitrile (PAN), is introduced. Unlike fibers generated via a conventional stabilization process, which relies on air-based stabilization to transform the PAN molecules into ring structures fundamental to carbon fibers, the hybrid fibers are annealed in an Ar atmosphere. This unique approach suggests MXene can serve as an oxygen provider that is essential for stabilizing PAN. As a result, significantly improved interfiber compactness is achieved and the oxidation stability of MXene is enhanced under atmospheric conditions. The resulting fibers exhibit exceptional stability, even after extended exposure to high humidity and elevated temperatures. This highlights the suitability of the thermally annealed MXene-PAN (T-MX-PAN) fibers as robust electric heating elements. Notably, these fibers consistently generate heat over 1800 bending cycles. When integrated into fabrics, they demonstrate the capability to generate sufficient heat for melting ice and rapid evaporation. This study highlights the potential of T-MX-PAN fibers as next-generation wearable heaters and offers valuable insights into advancing wearable technology in demanding environments.

The role of SRPK1-mediated phosphorylation of SR proteins in the chromatin configuration transition of mouse germinal vesicle oocytes.

Meiotic resumption in mammalian oocytes involves nucleus and organelle structural changes, notably chromatin configuration transitioning from non-surrounding nucleolus (NSN) to surrounding nucleolus (SN) in germinal vesicle (GV) oocytes. Our study found that nuclear speckles, a subnuclear structure mainly composed of serine-arginine (SR) proteins, changed from a diffuse spotted distribution in mouse NSN oocytes to an aggregation pattern in SN oocytes. We further discovered that SRPK1, an enzyme phosphorylating SR proteins, co-localized with NS at SN stage and NSN oocytes failed to convert into SN oocytes after inhibiting the activity of SRPK1. Furthermore, the typical structure of chromatin ring around the nucleolus in SN oocytes collapsed after inhibitor treatment. To explore the underlying mechanism, phosphorylated SR proteins were confirmed to be associated with chromatin by salt extraction experiment, and in situ DNase I assay showed that the accessibility of chromatin enhanced in SN oocytes with SRPK1 inhibited, accompanied by decreased repressive modification on histone and abnormal recurrence of transcriptional signal. In conclusion, our results indicated that SRPK1-regulated phosphorylation on SR proteins was involved in the NSN to SN transition and played an important role in maintaining the condensation nucleus of SN oocytes via interacting with chromatin.

High‐Energy Nitrogen Rings Stabilized by Superatomic Properties

AbstractHow to stabilize nitrogen‐rich high‐energy‐density molecules under conventional conditions is particularly important for the energy storage and conversion of such systems and has attracted extensive attention. In this work, the theoretical study shows for the first time that the stabilization mechanism of the nitrogen ring conforms to the superatomic properties at the atomic level. This result occurs because the stabilized anionic nitrogen rings generally exhibit planar high symmetry and the injected electrons occupy the superatomic molecular orbitals (SAMOs) of the nitrogen rings. According to these results, the typical stabilized anionic nitrogen ring structures N64−, N5−, and N42− are identified, which possess delocalized molecular orbitals with the same symmetry as the atomic orbitals and electron arrangement consistent with the electron shell arrangement of the atom. On this basis, a pathway is further designed to stabilize nitrogen rings by introducing metal atoms as electron donors to form neutral ThN6, LiN5, and MgN4 structures, thereby replacing the anionization of systems. This study highlights the importance of developing nitrogen‐rich energetic materials from the perspective of superatoms.

Some Remarks Regarding Special Elements in Algebras Obtained by the Cayley–Dickson Process over Zp

In this paper, we provide some properties of k-potent elements in algebras obtained by the Cayley–Dickson process over Zp. Moreover, we find a structure of nonunitary ring over Fibonacci quaternions over Z3 and we present a method to encrypt plain texts, by using invertible elements in some of these algebras.

Mesoscopic ring element growth and deformation induced biofilm streamer evolution in microfluidic channels

ABSTRACT In a fluid environment, biofilms usually form and grow into streamers attached to solid surfaces. Existing research on single streamers studied their formation and failure modes. In the experiment on biofilm growth in a microfluidic channel, we found that rings composed of bacteria and an extracellular matrix are important elements on a mesoscopic scale. In the fluid environment, the failure of these ring elements causes damage to streamers. We simulated the growth and deformation of the ring structure in the micro-channel using multi-agent simulation and fluid–structure coupling of a porous elastic body. Based on this, we simulated the biofilm evolution involving multi-ring deformation, which provides a new length scale to study the biofilm streamer dynamics in fluid environments.

Theoretical realization of tunable hollow beams using a periodical ring structure with a complex phase

Hollow beam is a peculiar structure beam, which has been widely used in various areas. Here, we propose a novel diffraction optical element to generate tunable hollow beams. This element is composed of periodic concentric rings. The phase of each ring is periodically distributed between −π and π and satisfies a complex variable function. By tuning the parameters of the structure, we can flexibly manipulate the size and length of the hollow beam. The length of the beam can be increased from 98 λ to 248 λ, and the full width at half maximum varies from 0.43 λ to 0.61 λ. Moreover, the light intensity and side lobe of the hollow beam can also be regulated using the designed diffraction optical element. The potential applications of this highly tunable hollow beam include optical nanomanipulation, microscopic imaging, and nanolithography.

Microstructure Evolution of Polyacrylonitrile-Based Fibers during Thermal Pre-Oxidation

In this work, pre-oxidized polyacrylonitrile fibers are treated with ultrasonic etching and solution etching to produce ultra-thin sections. The evolution of the fibers’ microstructure in the pre-oxidation process is observed, and the transformation model of the microstructure of the pre-oxidized fibers is proposed. Scanning electron microscopy and high-resolution transmission electron microscopy were used to observe the microstructure changes of the fibers. Fourier transform infrared spectroscopy and X-ray diffraction were used to observe the chemical structure transformation and crystallization degree of the fibers in the pre-oxidation process. The results revealed that pre-oxidized fibers exhibited a smooth surface, while their interior consisted of fibrils. The longitudinal microfibrils were connected by the transverse microfibrils and amorphous regions. The fracture morphology of the fibers shifted from ductile to brittle, and the cross-section gradually became smoother. The linear molecular chain of PAN transformed into a ring structure as pre-oxidation progressed, subsequently leading to the cross-linking of this ring structure into an orderly trapezoidal configuration. The connection between the fibrils was enhanced, and the fiber structure became more compact and stable.

Insights into the Biological Activities and Substituent Effects of Pyrrole Derivatives: The Chemistry-Biology Connection.

Pyrrole, with its versatile heterocyclic ring structure, serves as a valuable template for generating a diverse range of lead compounds with various pharmacophores. Researchers and scientists globally are intrigued by pyrrole and its analogues for their broad pharmacological potential, prompting thorough investigations aimed at advancing human welfare. This comprehensive review delves into the diverse activities exhibited by pyrrole compounds, encompassing their synthesis, reactions, and pharmacological properties alongside their derivatives. In addition to detailing the characteristics of pyrrole and its derivatives within the context of green chemistry, the review also examines microwave-assisted reactions. It provides insights into their chemical structures, natural occurrences, and potential applications across various domains. Furthermore, the article investigates structural alterations of pyrrole compounds and their implications on their functionality, highlighting their versatility as foundational elements for both functional materials and bioactive compounds. Ultimately, the review underscores the imperative for continued research and development in the realm of pyrrole compounds to unearth novel activities and advantages.

Rheology of polyborazanes with various molecular structures and dynamic transformation process

AbstractThe molecular structure of polymer precursors significantly affects their rheological properties, thermal stability, and ceramic conversion rates. For the first time, we revealed the effects of polyborazane molecular structure on rheology and molecular configuration dynamic transformation process. The systems studied are polyborazane precursors with rigid six‐membered ring structures. We synthesized precursors with different molecular structures, including polyborazanes with varying degrees of branching and molecular chain flexibility, and investigated how molecular structure affects viscosity under different conditions of temperature, time, and shear rates. The results indicate that decreasing the branching degree enhances thermal stability and reduces both zero‐shear viscosity and infinite‐shear viscosity. Increasing the flexibility of molecular chains notably reduces infinite‐shear viscosity, while having minimal impact on zero‐shear viscosity and thermal stability. In conclusion, the ideal molecular structure should aim to increase the flexibility of the molecular chains while maintaining a certain degree of branching, such as a dendritic molecular configuration. By correlating viscosity data with molecular structure, we constructed a dynamic transition process of molecular chain entanglement, disentanglement, and crosslinking. This research is essential for understanding polymer rheology and its applications in industry, particularly in designing and synthesizing precursor structures for producing various ceramic fibers through Polymer‐Derived Ceramics.

The Preparation and Contact Drying Performance of Encapsulated Microspherical Composite Sorbents Based on Fly Ash Cenospheres.

Sorption technologies are essential for various industries because they provide product quality and process efficiency. New encapsulated microspherical composite sorbents have been developed for resource-saving contact drying of thermolabile materials, particularly grain and seeds of crops. Magnesium sulfate, known for its high water capacity, fast sorption kinetics, and easy regeneration, was used as an active moisture sorption component. To localize the active component, porous carriers with an accessible internal volume and a perforated glass-crystalline shell were used. These carriers were created by acid etching of cenospheres with different structures isolated from fly ash. The amount of magnesium sulfate included in the internal volume of the microspherical carrier was 38 wt % for cenospheres with ring structures and 26 wt % for cenospheres with network structures. Studies of the moisture sorption properties of composite sorbents on wheat seeds have shown that after 4 h of contact drying the moisture content of wheat decreases from 22.5 to 14.9-15.5 wt %. Wheat seed germination after sorption drying was 95 ± 2%. The advantage of composite sorbents is the encapsulation of the desiccant in the inner volume of perforated cenospheres, which prevents its entrainment and contamination and provides easy separation and stable sorption capacity in several cycles.

Interfacial effects of SHMP/polycarboxylate synergistic reduction on coal surface wettability: Atomic force microscopy and density functional theory

The objective of this study was to elucidate the cooperative modification mechanism of anionic composite pharmaceuticals on coal substrates. Composite pharmaceuticals were synthesized using sodium hexametaphosphate (SHMP) and sodium polycarboxylate to reduce coal hygroscopicity. The mesoscopic alteration process between the coal surfaces and the compound pharmaceuticals was examined via atomic force microscopy (AFM). AFM showed that SHMP was multilayer-adsorbed on coal via electrostatic and hydrogen bonding, while sodium polycarboxylate was single layer-adsorbed at the SHMP layer via electrostatic interactions. Composite pharmaceutical adhesion to coal was lower than that for individual pharmaceuticals, indicating synergistic effects. The mechanism underpinning the microscopic synergistic effect of complex pharmaceuticals on the coal surface was further examined using density functional theory (DFT) at the molecular scale. DFT calculations showed that the adsorption energy of SHMP binding to a sodium polycarboxylate molecule was greater than that of SHMP binding to two identical pharmaceutical molecules. The SHMP portion generally interacted with the aromatic coal nucleus via its ring structure, exposing the sodium polycarboxylate carbon chain to maximize the adsorption energy. Combining DFT and AFM provided insight into the composite pharmaceutical function, and a theoretical framework for coal flotation separation was established.

Pectoral Fin Propulsion Performance Analysis of Robotic Fish with Multiple Degrees of Freedom Based on Burst-and-Coast Swimming Behavior Stroke Ratio

The pectoral fin propulsion of a bionic robotic fish always consists of two phases: propulsion and recovery. The robotic fish moves in a burst-and-coast swimming manner. This study aims to analyze a pair of bionic robotic fish with rigid pectoral fin propulsion with three degrees of freedom and optimize the elliptical propulsion curve with the minimum recovery stroke resistance using computational fluid dynamics methods. Then, the time allocated to the propulsion and recovery phases is investigated to maximize the propulsion performance of the bionic robotic fish. The numerical simulation results show that when the time ratio of the propulsion and recovery phases is 0.5:1, the resistance during the movement of the robotic fish is effectively reduced, and the drag-reducing effect is pronounced. According to a further analysis of pressure clouds and vortex structures, the pressure difference between the upstream and downstream fins of the pectoral fin varies with different stroke ratios. The increase in recovery phase time helps to prevent premature damage to the vortex ring structure generated during the propulsion process and improves propulsion efficiency.

High Sensitivity Triboelectric Based Flexible Self-Powered Tactile Sensor with Bionic Fingerprint Ring Structure.

Flexible self-powered tactile sensors, with applications spanning wearable electronics, human-machine interaction, prosthetics, and soft robotics, offer real-time feedback on tactile interactions in diverse environments. Despite advances in their structural development, challenges persist in sensitivity and robustness, particularly when additional functionalities, such as high transparency and stretchability. In this study, we present a novel approach integrating a bionic fingerprint ring structure with a PVDF-HFP/AgNWs composite fiber electrode membrane, fabricated via 3D printing technology and electrospinning, respectively, yielding a triboelectric nanogenerator (TENG)-based self-powered tactile sensor. The sensor demonstrates high sensitivity (5.84 V/kPa in the 0-10 kPa range) and rapid response time (10 ms), attributed to the microring texture on its surface, and exhibits exceptional robustness, maintaining electrical output integrity even after 24,000 cycles of loading. These findings highlight the potential of the microring structures in addressing critical challenges in flexible sensor technology.

Harnessing the duality of bases toward controlled color and fluorescence.

Bases can promote keto-enol tautomerism, a prevalent form of prototropic tautomerism, and facilitate the ring opening of anhydride ring structures. The intrinsic chemical distinctions between these processes provide an opportunity to modulate these seemingly parallel reactions. However, this potential remains largely unexplored. In this work, we report homophthalic anhydride, the first molecule exhibiting simultaneous halochromism, turn-on fluorescence (halofluorochromism), and subsequent self-destruction. Through comprehensive spectroscopic analysis and theoretical calculations, we unravel the mechanisms underlying these phenomena, revealing that the pivotal roles of the base's basicity and nucleophilicity specifically allow us to achieve controlled durations of color change and turn-on fluorescence. Capitalizing on these intriguing properties, we develop a highly dynamic CMY (cyan-magenta-yellow) palette ideal for entity encryption and anti-counterfeiting applications. Our work reshapes the understanding of the relationship between the basicity and nucleophilicity of bases, enriching the comprehension of keto-enol tautomerism and homophthalic anhydride chemistry, and unveils a spectrum of potential applications.

Luminescent tetranuclear copper(I) and gold(I) heterobimetallic complexes: A phosphine acetylide amidinateorthogonal ligand framework for selective complexation.

The synthesis of phosphine acetylide amidinate stabilized copper(I) and gold(I) heterobimetallic complexes was achieved by reacting ligand [{Ph2PC≡CC(NDipp)2}Li(thf)3] (Dipp = N,N'-diisopropylphenyl) with CuCl and Au(tht))Cl, yielding the eight membered ring [{Ph2PC≡CC(NDipp)2}2Cu2] and the twelve membered ring [{Ph2PC≡CC(NDipp)2}2Au2]. {Ph2PC≡CC(NDipp)2}2Cu2] features a Cu2 unit, which is bridged by two amidinate ligands, served as a metalloligand to synthesize the heterobimetallic CuI/AuI complexes [{(AuX)Ph2PC≡CC(NDipp)2}2Cu2] (X = Cl, C6F5). In these reactions the central ring structure is retained. In contrast, when the twelve membered ring [{Ph2PC≡CC(NDipp)2}2Au2] was reacted with CuX (X = Cl, Br, I and Mes), the reaction led to rearrangement of the central ring structure to give [{(AuX)Ph2PC≡CC(NDipp)2}2Cu2] (X = Cl, Br, I and Mes), which feature the same the eight membered Cu2 ring as above. These compounds were also synthesized by a one-pot reaction. The luminescent heterobimetallic complexes were further investigated for their photophysical properties.

Matrices of the Zero Divisor Graphs of Classes of 3-Radical Zero Completely Primary Finite Rings

The study of finite completely primary rings through the zero divisor graphs, the unit groups and their associated matrices, and the automorphism groups have attracted much attention in the recent past. For the Galois ring R′ and the 2-radical zero finite rings, the mentioned algebraic structures are well understood. Studies on the 3-radical zero finite rings have also been done for the unit groups and the zero divisor graphs Γ(R). However, the characterization of the matrices associated with these graphs has not been exhausted. It is well known that proper understanding of the classification of zero divisor graphs with diameter 2 and girth 3 can provide insights into the structure of commutative rings and their zero divisors. In this study, we consider a class of 3-radical zero completely primary finite rings whose diameter and girth are 2 and 3 respectively. We enhance the understanding of the structure of such rings by investigating their Adjacency, Laplacian and Distance matrices.

Ortho-Halobenzyl Halides as Precursors for the Synthesis of Five- to Nine-Membered Ring Structures Employing Transition Metals as Catalysts

AbstractThis review highlights the multifaceted usefulness of o-halobenzyl halides as pivotal substrates for the construction of five- to nine-membered cyclic structures with the aid of transition metals as catalysts. These privileged entities engage dual active sites, enabling the combination of both intermolecular benzylation and intramolecular arylation strategies that directs the formation of a diverse repository of cyclic structures. The introduction of transition-metal catalysis in cross-coupling transformations sparked a revolution in forging aryl–heteroatom bonds, culminating in the evolution of more potent methodologies for the synthesis of a wide spectrum of valuable compounds. Furthermore, the associated pharmaceutical and biological attributes of these cyclic structures augment their significance in medicinal chemistry research. This review aims to showcase the importance of this synthetic methodology and its far-reaching applications in synthesis.1 Introduction2 Synthesis of Five-Membered Rings3 Synthesis of Six-Membered Rings4 Synthesis of Seven-Membered Rings5 Synthesis of Eight- and Nine-Membered Rings6 Conclusion

Disentangling the Conformational Space and Structural Preferences of Tetrahydrofurfuryl Alcohol Using Rotational Spectroscopy and Computational Chemistry.

The influence of the hydroxymethyl (CH2OH) group on the tetrahydrofuran (THF) ring structure was investigated by disentangling the gas phase conformational landscape of the sugar analogue tetrahydrofurfuryl alcohol (THFA). By combining rotational spectroscopy (6-20 GHz) and quantum chemical calculations, transitions corresponding to two stable conformers of THFA and their 13C isotopologues were observed and assigned in the rotational spectrum. The positions of the C atoms were precisely determined to unambiguously distinguish between nearly isoenergetic pairs of conformers that differ in their ring configurations: envelope (E) versus twist (T). The rotational spectrum confirms that the E ring geometry is favoured when the CH2OH fragment lies gauche (-) to the THF backbone (OCCO ~-60°) whereas the T form is more stable for the gauche (+) alignment of the substituent (OCCO ~+60°). The observed spectral intensities suggest that conformational relaxation of the THF geometry (E↔T) to the more stable form readily occurs within the pairs of g- and g+ conformers which is consistent with the low barriers (1.5-1.7 kJ mol-1) for conversion determined via transition state calculations. Insights into the intramolecular hydrogen bonding and other weak interactions stabilizing the lowest energy structures of THFA were derived and rationalized using non-covalent interaction analyses.