Simple Coupling Research Articles

A Fully Coupled Numerical Model for Unbonded Post-tensioned Timber Structures

AbstractThe paper presents a fully Lagrangian mesh-free solver to simulate the dynamic behavior of post-tensioned timber structures. Weakly Compressible Smoothed Particle Hydrodynamics (SPH) is employed to model both the timber and the tendon. An efficient and simple coupling method between the timber and the tendon is proposed by considering the numerical stability. Besides, the same coupling algorithm is used to model the interaction between column and beam elements. Although the column is treated as rigid in the simulations, the coupling algorithm accounts for the initial compression of the column resulting from post-tensioning. For the verification of the code for solids and material nonlinearity of timber, benchmark problems available in the literature are used. Finally, the solver's capability is demonstrated through dynamic analysis of post-tensioned timber structures. The solutions obtained for all the cases are in good agreement with the experimental and theoretical data, which indicates the applicability and accuracy of the solver.

Enhanced removal of phosphate from aqueous solutions by oxygen vacancy-rich MgO microspheres: Performance and mechanism

The efficient removal of phosphate from water environments was extremely significant to control eutrophication of water bodies and prevent further deterioration of water quality. In this study, oxygen vacancy-rich magnesium oxide (OV–MgO) microspheres were synthesized by a simple solvothermal method coupling high-temperature calcination. The effects of adsorbent dosage, contact time, initial pH and coexisting components on phosphate adsorption performance were examined. The physicochemical properties of OV-MgO microspheres and the phosphate removal mechanisms were analyzed by various characterization techniques. The maximum adsorption capacity predicted by the Sips isotherm model was 379.7 mg P/g for OV-MgO microspheres. The phosphate adsorption in this study had a fast adsorption kinetics and a high selectivity. OV-MgO microspheres had a good acid resistance for phosphate adsorption, but their adsorption capacity decreased under alkaline conditions. The electrostatic attraction, ligand exchange, surface precipitation, inner-sphere surface complexation and oxygen vacancy capture were mainly responsible for efficient removal of phosphate from aqueous solutions. This study probably promoted the development of oxygen vacancy-rich metal (hydr)oxides with potential application prospects.

A facile paper-based chromatography coupled Au nanodendrite on nickel foam for application in separation and SERS measurement

A simple paper-based chromatography coupling with nickel foam decorated Au nanodendrite (PP-AuND/NiF) was fabricated for simultaneous separation and surface-enhanced Raman scattering (SERS) detection of Rhodamine-6G (R6G) from a mixture of analytes. The three-dimensional porous nickel foam (NiF) was employed as a sampling diffusion platform, and AuND with a high surface active area beneficial for SERS efficiency was electro-deposited directly onto the NiF frame. The structure of AuND/NiF was characterized by X-ray diffraction and scanning electron microscopy. The AuND/NiF could detect R6G at 0.1 nM, and the enhancement factor was 1.84 x 106. The AuND/NiF was durable, with a slight signal decrease after 6 m of drop-testing. Also, upon three days of exposure to ambient air, the signal droped only 3.35 %. Subsequently, the PP-AuND/NiF was constructed by directly situating AuND/NiF on a paper strip, serving as a sample in and out to AuND/NiF. A mixture of two SERS active compounds, namely 2-Naphthalenethiol (2-NpSH) and Rhodamine 6G (R6G), was prepared in ethanol: water (1:1) solution to evaluate PP-AuND/NiF separation capability. Raman measurements along different distances of AuND/NiF were performed, and the signal of 2-NpSH was dismissed after 3.0 mm, while R6G’s signals were observed throughout AuND/NiF. In general, the PP-AuND/NiF demonstrated effective separation and SERS measurement of analytes in a mixture, which could be applicable for more complex samples in the future, especially in clinical analysis.

A simple and novel coupling method for CFD–DEM modeling with uniform kernel-based approximation

A simple and novel coupling method for CFD–DEM modeling with uniform kernel-based approximation

Synthesis of Anti-oxidant Steroids by Hybridisation with Nitroxides

AbstractSteroidal–nitroxide hybrid molecules and non-radical controls were synthesised in good yields using simple carbodiimide coupling. An unexpected product arose from reactions between the nitroxide moiety and the solvent THF. Methoxyamine derivatives of the nitroxide drug hybrids were produced using Fenton chemistry without side reactions occurring on the steroid. The hybrid compounds bind to the glucocorticoid receptor and are relevant for the study of radical biological chemistry and redox-related disease processes.

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.

(o-CF3PhO)3P as a simple coupling reagent for direct amidation via activation of amines

A new coupling reagent was applied in a simple and unprecedented manner for direct amidation. This approach enabled amide bond formation via activation of amines, which was verified by control experiments and DFT calculations.

Advances in research based on antibody-cell conjugation.

Antibody-cell conjugation (ACC) technology is a new research direction in medicine and biotechnology in recent years. The concept of ACC was proposed by Hsiao et al. and developed into a viable cell therapy technology, which refers to the cells with specific functions. Such as natural killer cells (NK cells), cytokine induced killer cells (CIK) and other immune cells and monoclonal antibodies through the linker together formed conjugate. ACC directly modifies specific antibodies on the cell surface through a simple and effective chemical coupling method to enable cells to have new functions. ACC has been developed for the treatment of various diseases, including cancers of the blood system and solid tumors. This paper reviews the current ACC construction methods, challenges and future development directions.

On‐Surface Ullmann‐Type Coupling: Reaction Intermediates and Organometallic Polymer Growth

AbstractUllmann‐type coupling is the most widely used on‐surface reaction to form rationally designed bottom‐up molecular nanoarchitectures. A commonly observed reaction product in this reaction is an organometallic phase, however little is known about the formation of this phase. The on‐surface polymerization of the prochiral precursor 6,12‐dibromochrysene (DBCh) on Ag(111) is studied. Upon annealing of DBCh on Ag(111), a linear organometallic polymer forms. However, the delicate energy balance involved in the polymerization of DBCh is such that, at room temperature, several reaction intermediates, which eventually lead to the formation of the organometallic polymer, can be observed experimentally. Organometallic monomers, dimers, and trimers are finds, that self‐assemble into distinct networks. The experimental availability of these reaction intermediates provides key insights into the formation of the organometallic polymer. Comparing the chirality of the intermediates and the polymer sheds additional light on the reaction mechanism leading to the formation of the polymer. The main finding is that the organometallic polymer is not formed by a simple coupling of the reaction intermediates, but rather requires the breaking and re‐establishing of the C─Ag bonds. Additionally, a Br‐enhanced growth mode is observed, where the split‐off halogens align the polymers, which results in an increased polymer length.

Boosting photocatalytic antibiotic degradation with simultaneous H2O2 production of g-C3N4 by building dual-dragging force for efficient charge separation

Graphitic carbon nitride (g-C3N4) is a promising candidate for photocatalytic antibiotic degradation with simultaneous H2O2 production. However, g-C3N4 suffers from a high charge recombination and insufficient visible-light absorption. Herein, the benzene-ring and cyano groups were successfully grafted onto the surface of g-C3N4 (BCN-ND) by a simple coupling route involving copolymerization and secondary calcination, which provided a dual-dragging force was generated for the directional separation of photogenerated electrons and holes. The benzene-ring establishes a mid-state slightly above the valence band, which results in a dragging force for holes and extends the response of g-C3N4 to visible light. Moreover, the cyano group exhibits a powerful electron-withdrawing capacity, acting as an electron-dragging force and narrowing the intrinsic bandgap. Therefore, BCN-ND exhibits remarkable photocatalytic activity with a sulfamethoxazole degradation percentage of 99.5 % and simultaneous H2O2 production of 62 μmol/L after 80 min of visible light irradiation. This work provides new perspectives for enhancing photocatalytic activity by constructing of a dual-dragging center for oppositely directional charge separation.

Feature Disentanglement Network: Multi-Object Tracking Needs More Differentiated Features

To reduce computational redundancies, a common approach is to integrate detection and re-identification (Re-ID) into a single network in multi-object tracking (MOT), referred to as “tracking by detection.” Most of the previous research has focused on resolving the conflict between the detection and Re-ID branches, considering it a simple coupling. In our work, we uncover that the entangled state between the detection and Re-ID tasks is much more complex than previous idea, resulting in a form of competition that degrades performance. To address the preceding issue, we propose a feature disentanglement network that deeply disentangles the intricately interwoven latent space of features and provides differentiated feature maps for each individual task. Furthermore, considering the demand for shallow semantic features in the feature re-ID branch, we also introduce a feature re-globalization module to enrich the shallow semantics. By integrating two distinct networks into a one-shot online MOT method, we develop a robust MOT tracker (named HDGTrack ). We conduct extensive experiments on a number of benchmarks, and our experimental results demonstrate that our method significantly outperforms state-of-the-art MOT methods. Besides, HDGTrack is efficient and can run at 13.9 (MOT17) and 8.7 (MOT20) frames per second.

Mimetic inflation and self-reproduction

It is shown how self-reproduction can be easily avoided in the inflationary universe, even when inflation starts at Planck scales. This is achieved by a simple coupling of the inflaton potential with a mimetic field. In this case, the problem of fine-tuning of the initial conditions does not arise, while eternal inflation and the multiverse with all their widely discussed problems are avoided.

A new electric coupling and its applications on millimeter-wave SIW filter with high selectivity and controllable TZs

In this paper, a novel simple horizontal electric coupling (SHEC) structure is proposed, which only requires a single elliptical ring slot to be etched at the top layer of the substrate between the two adjacent SIW cavities. The working mechanism of SHEC is revealed using the equivalent magnetic current theory. The results indicate that the ring slot is divided into two semi-elliptical slots by the via-hole, and the induced electric fields generated by equivalent magnetic current near the slots enhance the extremely weak electric field intensity at the edge of the SIW cavities, resulting in the formation of electric coupling between the adjacent two cavities. As a verification, a fourth-order SIW filter operating at 27.96 GHz was designed based on the SHEC structure. The filter exhibits high selectivity with sharp roll-off of 114/105 dB/GHz and obtains controllable transmission zeros (TZs) by changing the size of the elliptical slot. Additionally, the proposed SHEC design has a regular via-holes arrangement and does not require etching slot on the bottom layer of the substrate, making it easy to accurately process, integrate, and package, providing a new approach for the design of millimeter-wave filters.

A rhythmically pulsing leaf-spring DNA-origami nanoengine that drives a passive follower

Molecular engineering seeks to create functional entities for modular use in the bottom-up design of nanoassemblies that can perform complex tasks. Such systems require fuel-consuming nanomotors that can actively drive downstream passive followers. Most artificial molecular motors are driven by Brownian motion, in which, with few exceptions, the generated forces are non-directed and insufficient for efficient transfer to passive second-level components. Consequently, efficient chemical-fuel-driven nanoscale driver–follower systems have not yet been realized. Here we present a DNA nanomachine (70 nm × 70 nm × 12 nm) driven by the chemical energy of DNA-templated RNA-transcription-consuming nucleoside triphosphates as fuel to generate a rhythmic pulsating motion of two rigid DNA-origami arms. Furthermore, we demonstrate actuation control and the simple coupling of the active nanomachine with a passive follower, to which it then transmits its motion, forming a true driver–follower pair.

New sulfonamide-tethered coumarin derivatives as potential DNA gyrase inhibitors: Design, synthesis, antimicrobial evaluation, and in silico study

A new series of coumarin-6-sulfonamide derivatives 3–16 have been synthesized via simple and convenient coupling reaction of coumarin-6-sulfonyl chloride with different sulfa drugs and various amino-heterocycles. The antimicrobial activity of the new compounds was evaluated against S. aureus ATCC 6538, E. coli ATCC 25933, C. albicans ATCC 10231, and A. niger NRRL A-326. Compound 12 showed potent antimicrobial activities against all pathogenic strains, with MIC values of 4.88 μg/mL against S. aureus and 9.76 μg/mL against C. albicans, exceptionally 4-fold more potent than neomycin control drug (MIC= 19.53 and 39.06 μg/mL respectively), and an MIC value of 39.06 μg/mL against E. coli, equipotent with neomycin. Meanwhile, compound 10 was equipotent with neomycin against both S. aureus and C. albicans. Additionally, compound 14 was equipotent with neomycin against S. aureus, and 2-fold more potent that neomycin against C. albicans. Further investigations showed that compounds 10 and 12 strongly inhibited DNA gyrase (IC50= 2.463 and 1.793μg/mL respectively), with compound 12 being closely equipotent with the reference novobiocin drug (IC50= 1.425μg/mL). Docking studies of compounds 10 and 12 on the active site of DNA gyrase confirmed their ability to form stable complexes with the target enzyme. According to ADME data, the bioavailability profile of compound 12 was high, and its physicochemical and pharmacological characteristics were consistent with Lipinski's RO5 anticipated constraints. Collectively, these data strongly highlight the efficiency of our multidisciplinary approach in the field of novel potent antimicrobial DNA gyrase inhibitors.

Disturbance Observer-Based Adaptive Neural Network Output Feedback Control for Uncertain Nonlinear Systems.

This article is devoted to the output feedback control of nonlinear system subject to unknown control directions, unknown Bouc-Wen hysteresis and unknown disturbances. During the control design process, the design obstacles caused by unknown control directions and Bouc-Wen hysteresis are eliminated by introducing linear state transformation and a new coordinate transformation, which avoids using the Nussbaum function with high-frequency oscillation to deal with the issue. Besides, to settle the issue caused by the unknown disturbances, a novel nonlinear disturbance observer is designed, which has the characteristics of simple structure, low coupling, and easy implementation. Especially, a compensation item is constructed to offset the redundant items generated in the backstepping design process. Simultaneously, using the neural network and backstepping technology, an output feedback controller is devised. The controller ensures that all closed-loop signals are bounded, and the system output, state observation error, and disturbance observation error converge to a small neighborhood of the origin. Finally, to illustrate the effectiveness of the proposed scheme, simulation verification is carried out based on a numerical example and a Nomoto ship model.

Phosphonic Acid-Functionalized MIL-53(Al) As an Efficient Sorbent for Trace Rare Earth Elements Preconcentration, Storage and Their Determination by X-ray Fluorescence Spectrometry.

In this work, a simple and novel method coupling solid phase extraction (SPE) with X-ray fluorescence spectrometry (XRF) is proposed for the simultaneous determination of 15 kinds of trace rare earth elements (REEs) in water samples. A phosphonic acid functionalized metal-organic framework named BPG-MIL-53(Al) was prepared via postsynthetic modification and served as an efficient adsorbent for these REEs. The prepared BPG-MIL-53(Al) could almost completely adsorb REEs in 5 min under neutral conditions. After filtration, REEs-adsorbed BPG-MIL-53(Al) was deposited on a filter membrane to form a thin film, which was directly analyzed by XRF. The XRF intensities of the REEs-retained MOF disc remained almost unchanged after six months. Taking advantage of this strategy, XRF was able to quantitate ng mL-1 levels of REEs in water samples, achieving impressive limits of detection in the range of 0.4-4.7 ng mL-1. The proposed method was applied to the on-site collection and analysis of REEs in real water samples with desirable accuracy and spike recoveries obtained.

Coupled strain and temperature gradient analysis in curved surfaces

AbstractA common method in experimental mechanics is 3D digital image correlation (DIC) for determining deformations of curved surfaces, whereby the motion of material points is measured. The temperatures induced by the deformation of surfaces or by other heat sources are of particular interest as well. In this context, surface temperatures can be measured using infrared thermography systems. However, the disadvantage of this approach is that a thermographic camera only provides the two‐dimensional temperature distribution (plane images) of three‐dimensionally curved surfaces. Thus, the temperature and temperature gradients on the curved surface assigned to material points cannot be specified. However, for particular problems the temperature and the motion of material points are of particular interest. In the literature, planar problems are studied and simplifying assumptions are made so that a simple coupling of thermography and DIC is possible. In contrast, this contribution presents a method where 3D DIC is coupled with thermography in such a way that the temperature, temperature gradient, as well as displacement and strain distributions at material points of curved surfaces can be determined over temporal processes. The method also allows a continuous strain and temperature gradient determination over the entire domain, since a special class of functions named radial basis functions is used for interpolating the measured data.

Synthesis of Pyridin-1(2H)-ylacrylates and the Effects of Different Functional Groups on Their Fluorescence.

While fluorescent organic materials have many potential as well as proven applications and so have attracted significant attention, pyridine-olefin conjugates remain a less studied subset of such systems. Herein, therefore, we report on the development of the straightforward syntheses of pyridin-1(2H)-ylacrylates and the outcomes of a study of the effects of substituents on their fluorescent properties. Such compounds were prepared using a simple, metal-free and three-component coupling reaction involving 2-aminopyridines, sulfonyl azides and propiolates. The fluorescent properties of the ensuing products are significantly affected by the positions of substituents on the cyclic framework, with those located in central positions having the greatest impact. Electron-withdrawing groups tend to induce blue shifts while electron-donating ones cause red shifts. This work highlights the capacity that the micro-modification of fluorescent materials provides for fine-tuning their properties such that they may be usefully applied to, for example, the study of luminescent materials.

A Voltammetric Investigation of the Electrocatalytic Cycle Mechanism of Fe(I) and Mn(I) Complexes

Earth-abundant, first row, low coordinate transition metal complexes are promising candidates for the electrocatalysis of a variety of organic synthesis reactions. However, transition metal complexes in the M(I) state have the propensity to undergo disproportionation, hindering their ability to carry out the electrocatalytic cycle. In this study, we seek to identify and understand the mechanism by which the M(I) complexes may act as an electrocatalyst for a simple organic coupling reaction, beginning with the radicalization of benzyl bromide as a representative starting material. Initial characterization of the complex and its components by cyclic voltammetry demonstrate general stability of the catalyst, while equivalent additions of benzyl bromide exhibit the execution of the electron transfer and radical generation. Cyclic voltammetry simulations provide supplementary guidance into the relationship between benzyl bromide and the catalyst. Additional experiments conducted using analytical techniques such as mass spectrometry, x-ray spectroscopy, and nuclear magnetic resonance help to further characterize portions of the proposed mechanism and supporting details. Analysis to date suggests that the model electrocatalytic cycle is interrupted to an extent, with contributions from both disproportionation and substituted coordination at the transition metal center. Experimental and simulated voltammograms are qualitatively consistent with this proposed catalytic cycle interruption.