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The dynamic crack propagation trajectories play a crucial role in enhancing our understanding of spatial mechanisms involved in crack expansion. However, visualization of internal cracks under complex crack conditions has always been a challenge. Biological networks have been honed by many cycles of evolutionary selection pressure and are likely to yield reasonable solutions to such combinatorial optimization problems. This study applied the slime mould algorithm to improve the accuracy of internal crack localization in rocks and employed Minimum spanning tree and Gaussian mixture model to construct the crack propagation trajectories. By introducing the concept of bond length, the evolution characteristics of crack levels were effectively characterized. Research results showed that this approach effectively preserves essential crack localization information while mitigating the influence of interfering parameters, providing crack characterization results that exhibit high consistency with actual fracture patterns. The curves of cumulative bond length and relative bond length over time conform to the trend of a Growth/Sigmoidal curve. The strength of the bond was correlated with the temporal process of crack propagation. This result could be helpful for analyzing crack trajectories and predicting rock stability. [ABSTRACT FROM AUTHOR]

Regulating competitive reaction pathways to direct the selectivity of electrochemical CO2 reduction reaction toward a desired product is crucial but remains challenging. Herein, switching product from HCOOH to CO is achieved by incorporating Sb element into the CuS, in which the Cu−S ionic bond is coupled with S−Sb covalent bond through bridging S atoms that elongates the Cu−S bond from 2.24 Å to 2.30 Å. Consequently, CuS with a shorter Cu−S bond exhibited a high selectivity for producing HCOOH, with a maximum Faradaic efficiency (FE) of 72 %. Conversely, Cu3SbS4 characterized by an elongated Cu−S bond exhibited the most pronounced production of CO with a maximum FE of 60 %. In situ spectroscopy combined with density functional theory calculations revealed that the altered Cu−S bond length and local coordination environment make the *HCOO binding energy weaker on Cu3SbS4 compared to that on CuS. Notably, a volcano‐shaped correlation between the Cu−S bond length and adsorption strength of *COOH indicates that Cu−S in Cu3SbS4 as double‐active sites facilitates the adsorption of *COOH, and thus results in the high selectivity of Cu3SbS4 toward CO. [ABSTRACT FROM AUTHOR]

The geometry of hydrogen sulfide was studied by calculating potential energy surface (PES) with over 1800 configurations. The calculations were performed at very accurate CCSD(T)/aug‐cc‐pvz5 level. The most stable geometry on the PES has bond angle (H−S−H) of 92.40° and bond length (S−H) of 1.338 Å. The PES shows that hydrogen sulfide is a quite flexible molecule. Namely, it can change the bonding angle (H−S−H) in the range of 15.6° (from 84.6° to 100.2°) and the bond lengths (S−H) in the range of 0.082 Å (from 1.299 Å to 1.381 Å) with an energy increase of only 1.0 kcal/mol. An influence of hydrogen sulfide geometry on its hydrogen bonds was studied on several hydrogen sulfide/hydrogen sulfide and water/hydrogen sulfide dimers. It showed that the change of hydrogen sulfide geometry does not influence the strength of hydrogen bond. Fully optimized geometries in gas and water solution phases revealed structural differences of both monomers and dimers in gas phase and water phase. SAPT analysis of the optimized dimer geometries showed that in all the dimers electrostatic is the most dominant contribution, while, in the dimers with hydrogen sulfide, the influence of dispersion contribution becomes quite pronounced. [ABSTRACT FROM AUTHOR]

[Display omitted] The 57Fe Mössbauer isomer shift is not directly related to the oxidation state of iron, and therefore the evaluation of the oxidation state of iron from the isomer shift is problematic. The oxidation state affects the isomer shift only to the extent that it affects the Fe–X bond lengths. The isomer shift can be estimated based on the average Fe–X interatomic distance. [ABSTRACT FROM AUTHOR]

Controlling factors of potassium (K) isotopic fractionation in K-feldspar remain poorly constrained. In this study, we analyzed the K isotopic compositions of 11 K-feldspar samples from diverse lithological compositions. The degree of Al/Si order ranged from 0.22 to 0.94 (1.0 = completely ordered). Analyzed samples are mixtures of K-feldspar (>70 wt%) and coexisting albite. The relative contribution of K2O from the K-feldspar phase of the sample was over 98%, indicating that the K isotopic composition (δ41K) derives mainly from K-feldspar and hence reflects its behavior. The δ41K values of these samples range from –0.710 to –0.075‰, which are slightly correlated with the degree of Al/Si order. The correlations of δ41K with SiO2 and Al2O3 contents and the corresponding Al/Si mole ratios reveal that Al and Si play a significant role in the K isotopic behavior of K-feldspar. The correlations of δ41K with SiO2 and Al2O3 contents are attributed to the difference in K-O bond strengths. Compared to K-feldspar, the K content could be a better proxy for constraining the δ41K of plagioclase. Our results demonstrate that the δ41K of K-feldspar is dependent on its mineral chemistry, and its K isotopic composition may be insensitive to other factors, such as the source heterogeneity. The inference is further confirmed by comparing the δ41K values in this study with published δ41K values of K-feldspar from different sources. [ABSTRACT FROM AUTHOR]

Abstract The dynamic crack propagation trajectories play a crucial role in enhancing our understanding of spatial mechanisms involved in crack expansion. However, visualization of internal cracks under complex crack conditions has always been a challenge. Biological networks have been honed by many cycles of evolutionary selection pressure and are likely to yield reasonable solutions to such combinatorial optimization problems. This study applied the slime mould algorithm to improve the accuracy of internal crack localization in rocks and employed Minimum spanning tree and Gaussian mixture model to construct the crack propagation trajectories. By introducing the concept of bond length, the evolution characteristics of crack levels were effectively characterized. Research results showed that this approach effectively preserves essential crack localization information while mitigating the influence of interfering parameters, providing crack characterization results that exhibit high consistency with actual fracture patterns. The curves of cumulative bond length and relative bond length over time conform to the trend of a Growth/Sigmoidal curve. The strength of the bond was correlated with the temporal process of crack propagation. This result could be helpful for analyzing crack trajectories and predicting rock stability.

The adsorption of the C60 fullerene molecule has been studied in various configurations on a reconstructed Si(100) silicon surface. Among fullerenes, fullerene C60 is of particular importance since it has the most stable form and consists of 60 carbon atoms. Monocrystalline silicon has the diamond structure, the size of its crystal lattice is 5.43 Å. The MD-simulation calculations have been performed using the open source LAMMPS MD-simulator software package and the Nanotube Modeler computer program. The Tersoff interatomic potential has been used to determine the interactions between the Si-Si, C-C and Si-C atoms. The adsorption energy of the C60 molecule on the reconstructed Si(100) surface, the bond lengths and the number of bonds formed depend on the adsorption geometry, i.e. at what point on the substrate the molecule is adsorbed and in what configuration.

The accuracy of describing the geometry of polyenes in their ground electronic state by various methods is examined. To achieve high accuracy, it is proposed to use the SCS-MP2 method, taking into account the correlation of all electrons, including core ones, and using the cc-pwCVTZ atomic basis. It is shown that, when using this approach, errors in the lengths of C–C bonds do not exceed 0.003 Å. The use of the RIJCOSX and DLPNO approximations speeds up calculations without significantly increasing the errors in bond lengths, but allows the proposed approach to be used to describe such large systems as carotenoids. [ABSTRACT FROM AUTHOR]

The adsorption of the C60 fullerene molecule has been studied in various configurations on a reconstructed Si(100) silicon surface. Among fullerenes, fullerene C60 is of particular importance, since it has the most stable form and consists of 60 carbon atoms. Monocrystalline silicon has the diamond structure, the size of its crystal lattice is 5.43 Å. The MD-simulation calculations have been performed using the open source LAMMPS MD-simulator software package and the Nanotube Modeler computer program. The Tersoff interatomic potential has been used to determine the interactions between the Si-Si, C-C and Si-C atoms. The adsorption energy of the C60 molecule on the reconstructed Si(100) surface, the bond lengths and the number of bonds formed depend on the adsorption geometry, i.e. at what point on the substrate the molecule is adsorbed and in what configuration. [ABSTRACT FROM AUTHOR]

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AbstractThe biogenesis of AgNiCuO nanocomposites using Bambusa seed extract as reducing and capping agents are calcinated at 500 °C. The crystal structure analysis was calculated using XRD data. The bond length of a nanocomposite was determined via FTIR analysis. FE-SEM and EDS were used to confirm the nanocomposite element composition and surface morphology. An effective core-shell-like structure of AgNiCuO nanocomposites was obtained, and the morphology of these nanocomposites was examined using a high-resolution electron microscope (HR-TEM). Selected Area Electron Diffraction (SAED) and X-ray diffraction confirmed nanocomposites are polycrystalline. The prepared green synthesis nanocomposites show the activity of the superior photocatalyst to degrade methylene Blue a hazardous dye, after 50 min of exposure to solar light radiation. The photocatalytic activity of AgNiCuO(0.050 g) at pH-7 exhibits the best photodegradation of methylene blue (MB), which also follows the pseudo-first-order kinetic model. [ABSTRACT FROM AUTHOR]

Background. The use of new drugs with high bioactivity in agriculture is relevant. One of them is the combination of o-phenylenediamine with a ligand that has potential biological activity. Purpose: Preparation of a mixed-ligand complex compound of o-phenylenediamine and 2,4- dihydroxybenzoic acid with Ni(II), study of synthesis conditions, determination of the crystal structure and physicochemical properties. Methodology. X-ray diffraction analysis (XRD) and IR spectroscopy (Xcalibur R Oxford Diffraction and IRAffinity-1S IR spectrometer) were used. Originality. For the first time, a mixed-ligand complex of o-phenylenediamine with Ni(II) was synthesized and the crystal structure was studied, Hirschfeld surface analysis and physicochemical properties of the synthesized complex were performed. Findings. A compound consisting of o-phenylenediamine, 2,4-dihydroxybenzoic acid and [(Ni(C6H8N2)2(C7H6O4)2)] was synthesized and its properties were studied. [ABSTRACT FROM AUTHOR]

Interface models of diamond-coated cemented carbide tool WC-Co / SiC/ Diamond with Co mass fraction of 6%, 8%, 10% and 12% were constructed. The influences of different deposition temperatures on the interface bonding strength were simulated with the molecular dynamics method, and the reasons were analyzed from perspectives of adhesion work and bond length distribution. The adhesion work analysis indicates that, compared with the other three Co content interface models, the two interfaces in WC-6% Co / SiC/ Diamond interface model have the highest adhesion work values at seven deposition temperatures. At different deposition temperatures, both interfaces of WC-6% Co / SiC and SiC/ Diamond in WC-6% Co / SiC/ Diamond have the highest adhesion work values of 2. 468 and 5. 394 J / m² at 1 123 and 1 173 K, respectively. The analysis results of bond length distribution indicate that, at any deposition temperature, compared with the other three Co content interface models, the maximum value of the bond length distribution range at each interface of WC-6% Co / SiC/ Diamond is smaller. The interface model obtained by sequentially depositing SiC layer on WC-6%Co substrate at 1 123 K and diamond coating on SiC layer at 1 173 K has the shortest interface bond length, the largest bond energy, and the best interface bonding property. Key words: diamond-coated cemented carbide; WC-Co / SiC/ Diamond; deposition temperature; Co content; interface [ABSTRACT FROM AUTHOR]

Today's construction industry has been more inclined to apply innovative rehabilitation techniques, including externally bonded (EB) fiber-reinforced polymer (FRP) composites on existing RC structures, rather than traditional strengthening methods. Indeed, the higher fatigue resistance of carbon FRPs (CFRPs) has made them superior strengthening tools for structures subjected to fatigue loading, such as RC bridge girders against daily traffic loads. However, the performance of RC structures retrofitted with EB–CFRP composites can be highly influenced by the bonding mechanism at the CFRP-to-concrete interface. The occurrence of debonding failure at the CFRP-to-concrete interface can result in premature failure of the EB–CFRP retrofitting system, thereby leading to rupture of the deficient structure. Therefore, an in-depth understanding of the bond behavior, especially under fatigue loading, would contribute to improving the efficiency of EB–CFRP strengthening techniques. To this end, in this work, we investigated the bond fatigue behavior through an experimental study. The parameters of CFRP composite type (laminate vs. fabric sheet), bond length, and CFRP-to-concrete width ratio were considered herein in order to examine their effectiveness on fatigue bond performance at the CFRP-to-concrete interface. The research results revealed that the CFRP composite system composed of the fabric sheet CFRP and the corresponding epoxy adhesive performed better than the CFRP-bonded joint with laminate CFRP in terms of fatigue life and residual load-carrying capacity. Furthermore, a modified bond fatigue-life model (S–N model), validated with existing research data, was proposed that successfully takes into consideration the effects of fatigue loading, concrete compressive strength, and CFRP-to-concrete width ratio. [ABSTRACT FROM AUTHOR]

In recent years, an increasing attention was devoted to evaluating the effects of temperature exposure on the bond properties between a steel bar and the surrounding concrete, with a lower focus on the effects on bond length and, more in general, on the consistency among existing design models, when considering a fire scenario. The current paper proposes a unified approach for both cast‐in and post‐installed rebars to evaluate the effects of temperature exposure on bond length and reinforcement detailing in reinforced concrete members in bending subjected to a simulated fire event. Starting from a consistent evaluation of decay of bond properties as a function of temperature, different geometrical configurations of beam/slab to column/wall connections are considered. For a given fire duration, the impact on bond length is evaluated as a function of bar position and size, also focusing on the potential modifications in the overall load‐transfer mechanism, when bond properties are excessively impaired. [ABSTRACT FROM AUTHOR]

The application of externally bonded (EB) carbon fiber reinforced polymer (CFRP) systems for strengthening existing structures, such as RC beams, has been widely approved in the construction industry worldwide for its numerous benefits. The CFRP-to-concrete bond has a governing role in the reliability and effectiveness of EB-CFRP systems. Indeed, failure of the CFRP-to-concrete bond can lead to rupture of CFRP-strengthened structures. Hence, ongoing research into assessment of bond behavior at the CFRP-to-concrete interface helps to bring more insightful clarity to the use of EB-CFRP strengthening techniques. The aim of this study is to evaluate the bond behavior between CFRP and concrete by conducting a series of pullout tests. The parameters considered include CFRP type (sheet versus laminate), bonded length, and bonded CFRP width. The results show that using CFRP fabric sheets can contribute to higher bond load-carrying capacity and ductility than CFRP laminates. Furthermore, through the analyses of databases in the literature, a bilinear bond–slip model is proposed that takes into account the CFRP width factor. Through a comparison, it is shown that the proposed model performs well in terms of predicting the maximum local bond stress and CFRP slippage. This research was aimed at investigating the use of CFRP composites for strengthening RC structures. The complexities regarding the behavior of CFRP-strengthened RC beams and columns, especially at the CFRP-to-concrete bond, provoked the authors to conduct this experimental study. The testing program was intended to evaluate the effect of certain parameters on the bond behavior of a CFRP-to-concrete interface. In addition, an analytical study was carried out to develop a model, capable of characterizing the interfacial behavior in terms of bond shear stress and bond slip. The proposed model proved to perform well at predicting the bond–slip behavior in a validation study. Findings obtained from this research can better familiarize civil engineers with the application of EB-CFRP strengthening techniques in concrete surfaces and possibly enhance the design of such retrofitting systems in deficient real-life RC structures. [ABSTRACT FROM AUTHOR]

This study evaluates the effectiveness of externally bonded small-patch ultrahigh-modulus (UHM) carbon fiber–reinforced polymer (CFRP) plates of 460 GPa modulus in extending fatigue life and slowing crack propagation in steel plates with simulated fatigue cracks. The study investigates a range of very short bond lengths for applications where bonding space may be limited or accessibility restricted, together with the effect of single- versus double-sided application, on fatigue performance. It also compares short UHM CFRP plates with similar length normal modulus (NM) (165 GPa) CFRP plates with regard to extending fatigue life and reducing stress concentration at the crack tip. Distributed fiber-optic sensors (DFOS) and digital-image correlation (DIC) are used to capture the full strain field and track crack growth. Results showed that fatigue life was increased by up to 2.0 and 2.34 times for single- and double-sided UHM CFRP repairs. As bond length increased from 25 to 100 mm, fatigue life increased from 1.36 to 2.0. UHM CFRP more effectively reduced stress concentration at the crack tip, by 60% compared with 37% for NM CFRP, indicating that it has the potential for superior fatigue life gains, relative to NM CFRP if the necessary bond length to prevent or delay debonding is provided. As debonding failure governed in this study, NM CFRP plates achieved comparable fatigue life extension. DIC tracking of crack growth matched the traditional "beach marking" technique with less than 6% difference. [ABSTRACT FROM AUTHOR]

This study seeks to identify bond strength and bond-slip behavior of deformed reinforcing bars under high sustained loads. ASTM A944 beam-end test specimens were subjected to sustained load levels ranging from 71 to 100% of their ultimate capacity. The sustained loading tests were conducted until bond failure or at least 20 days. Three of the specimens failed under sustained load at load levels as low as 80% of the control specimens. Subsequent loading of the specimens that survived the high sustained load showed that the residual ultimate capacity was not reduced by the application of sustained load. The slip creep under sustained load was on average 124% of the initial slip, and over 45% of the slip creep occurred in the first day. The effects of concrete cover depth and bond length were examined. With the available data, a simple time-dependent model for determining the bond-slip under high sustained loading was suggested. [ABSTRACT FROM AUTHOR]

In this review, the latest achievements in the field of multiply bonded organogermanium derivatives, mostly reported within the last two decades, are presented. The isolable Ge-containing analogues of alkenes, alkynes, 1,3-dienes, allenes, and vinylidenes are discussed, and for each class of unsaturated organogermanium compounds, the most representative examples are given. The synthetic approaches toward homonuclear multiply bonded combinations solely consisting of germanium atoms, and their heteronuclear variants containing germanium and other group 14 elements, both acyclic and cyclic, are discussed. The peculiar structural features and nonclassical bonding nature of the abovementioned compounds are discussed based on their spectroscopic and structural characteristics, in particular their crystallographic parameters (double bond length, trans-bending at the doubly bonded centers, and twisting about the double bond). The prospects for the practical use of the title compounds in synthetic and catalytic fields are also briefly discussed. [ABSTRACT FROM AUTHOR]

The C4H4 and C8H8 monocyclic polyene systems are treated automatically as the conjugated delocalized triplet molecules by Hückel molecular orbital (HMO) method, but this is inconsistent with their actual ground state structures associated with singlet state. In this work, both the singlet and triplet molecular structures of the four-membered ring and the eight-membered ring were optimized by density functional theory (DFT), and the more accurate π bond orders were calculated. Based on the DFT calculated results, we suggested a solution that can correctly compute the π bond orders in the C4H4 and C8H8 monocyclic polyene systems by using the HMO method. [ABSTRACT FROM AUTHOR]

Density functional (B3LYP)/6‐31G calculations have been performed on the electronic structure of neutral, cationic, and anionic from of hydroxychloroquine and chloroquine. Net atomic charges, bond length, dipole moment, and total energy of hydroxychloroquine and chloroquine are compared in order to explore the finer details of these molecules. Comparison shows that redistribution of charges on anionic form of hydroxychloroquine is over larger range as compared to other forms hydroxychloroquine and chloroquine, which favors the experimental results of pharmacokinetic studies. [ABSTRACT FROM AUTHOR]

Spike anchors are one of the most promising techniques to prevent or delay debonding in FRP reinforcement sheets. There are several parameters affecting the anchors' capacity, such as the embedment length and dowel angle. Regardless of the anchors' capacity, their contribution to the overall strength of the anchored joint is affected by a larger number of variables, including the bonded length behind the anchors, the number and arrangement of the anchors, and the contact surface between the anchor fan and the FRP sheet. This paper presents experimental results of 10 tests conducted on concrete beams. In the tests, anchored joints reached peak loads up to 155% of those of unanchored, bonded joints. The main finding of the research is that the bond length in front of and behind the anchors affects both the peak load and the overall behaviour, with unbonded anchored joints exhibiting a poor behaviour and premature slippage of the anchor, without achieving its failure due to fibre rupture. [ABSTRACT FROM AUTHOR]

The current study contributes to a better knowledge of the FCZ's characteristics and bioactivity. The ADMET properties have been calculated and the results have been illustrated; as a result, it has become quite popular for virtual pharmaceutical analysis. This research aims to examine FCZ's optimized structure and properties by analyzing various computational calculations. Bond length, Bond angle, Mulliken charges have been analyzed for the studies. The experimental geometrical parameters and theoretical data were compared with ADME parameters, biomarker properties, pH value, drug like nature, Marvin sketch, Swiss ADME to quantify molecular descriptors just as to survey atomic elements. ADMET properties introduce the influence of the drug levels and its kinetics with the tissues of the body. It also explains about the metabolism, toxicity of the drugs when introduced to the system. The analysis on pharmacokinetic properties has helped a lot in the drug development for further studies. The target prediction of FCZ has been studied along with the docking study. Docking study is an important program in order to study about the binding of the small ligand into a receptor like proteins. This method is very useful in drug discovery which provides insights into various studies. This will help in further development of the drugs which will finally help the society in large scale. FCZ helps pharmaceutical industry in developing the drugs to treat chronic disease when combined with other molecules. Hence the present study is really helpful in drug designing and in the development of new drugs. [ABSTRACT FROM AUTHOR]

Backround. In the synthesis of complex compounds, the study of metallocomplexes containing ligands with N, O - donor centers is of particular importance. Knowing about them solves the problem of competing coordination in coordination chemistry. Purpose. Development of optimal synthesis conditions, determination of the structure and composition of the complex compound of zinc nitrate with formamideand nicotinamide. Study of the thermal properties of zinc nitrate complex compound with mixed ligands.. Methodology. Differential thermal analysis, elemental analysis, quantum-chemical calculations. Originality. For the first time, a new coordination compound of zinc nitrate with formamide and nicotinamide was synthesized. The methods of coordination of ligands and the geometry of the coordination ring in the synthesized complex compound, the formation energy of the complex, the bond length and the distribution of atomic charges were studied based on several options, and the most optimal option was obtained. The thermal properties and thermolysis products of the synthesized complex were studied. Findings. Molecules of formamide, nicotinamide and a complex compound, on the basis of data on the length of bonds and the distribution of charges on atoms, participate in the formation of a compound, the composition [ZnL1∙L6∙(NO3)2]∙H2O. During its thermolysis, the products were studied in the temperature ranges. [ABSTRACT FROM AUTHOR]

We report the green chemistry reduction approach method for the synthesis of Manganese Oxide nanoparticles (MnO NPs), Copper Oxide nanoparticles (CuO NPs) and Manganese-doped Copper Oxide nanoparticles (Mn-doped CuO Nps). Aqueous extract from the seeds was used as reducing and capping agents. The detailed crystal structure analysis was investigated; crystallite size, crystallinity, morphological index, x-ray density, bulk density, specific surface area, porosity, Lorentz factor, Lorentz polarization factor and other parameters were calculated. Simple EDX mapping reveals the presence of Mn, Cu, O and C. FTIR analysis was used to determine the bond length of a nanocomposite. In the visible area, nanoparticles have higher optical absorption, with bandgaps varying from 1.79 (MnO), 2.18 eV (CuO) and 1.72 eV (Mndoped CuO). After 90 min, the photodegradation rate of Mn-doped CuO nanocatalysts was 93.73 % while using a smaller amount of catalyst (0.1 g) at pH 7. The pseudo-first-order MB photocatalytic decomposition kinetic model has a high correlation coefficient value (R2 > 0.95). It was found that Mn-doped CuO NPs have higher photocatalytic efficiency and can be used as potential photocatalysts for industrial dye degradation. [ABSTRACT FROM AUTHOR]

A new method for conversion of the distributed strain measurements to crack opening displacements (CODs) in structural elements is introduced. A hybrid approach involving theoretical and experimental strain distribution at the crack location was employed to formulate the conversion equation. The objective was to find a simple deterministic equation for practical field application that quantifies crack opening displacements directly from distributed strain measurements. The viability of the method was accomplished by experiments involving a 15-m steel beam with prefabricated flaws. A Brillouin scattering–based optical fiber sensor system was employed for distributed measurement of strains along the length of the 15-m-long beam. Two fiber Bragg grating (FBG)–based displacement sensors were also used for direct measurement of crack opening displacements at the locations of the flaws. The process involved defining and computing the bond length, which is the segment of the optical fiber affected by the presence of the crack. The distributed strain was integrated over the bond length for describing the crack opening displacements. In developing the method, it was necessary to also perform direct tension tests of the optical fiber for the acquisition of the mechanical properties. The proposed method takes into account the elastic and elastoplastic stages of deformations in the optical-fiber coating and the influence of plastic phenomena on the bond length. [ABSTRACT FROM AUTHOR]

The intrinsic activity of single-atom catalysts is influenced by the local electronic structures of metal centers, with existing modulation strategies limited to adjacent atomic coordination. However, the impacts of support surface geometry on local bonding environment, and thus electronic structures of single-atom centers have rarely been known. Here, we prepared highly curved B,N co-doped carbon-supported ruthenium catalyst with an ultra-low Ru loading of 0.4 wt%, which exhibited an ultrahigh turnover frequency (TOF) of 10 H 2 s−1 (38 times that of Pt/C) and superior stability in alkaline hydrogen evolution reaction (HER). We found that curving support surface induced the strain, resulting in 1.5% compressed Ru-N and 4% stretched Ru-B bonds, leading to the accumulation of positive charge and quenching of spin polarization at Ru sites, thereby achieving the optimal binding of H* and enhanced performance for HER. This work highlights the significant support effects upon the structural design of active sites. [Display omitted] • Two types of B, N co-doped carbon-supported Ru site catalysts with and without support surface curvature were synthesized. • Curving the support surface induces strain and thereby changes the local bond length at the Ru sites. • Regulating bond length increases the aggregation of positive charges and suppresses spin polarization at the Ru sites. • The B, N co-doped carbon-supported Ru site catalyst with curvature achieves optimal H* binding strength for HER. • The turnover frequency of Ru sites with curvature is significantly higher than those without surface curvature. [ABSTRACT FROM AUTHOR]

When the bond lengths of 11 molecules containing van der Waals bonds are optimized by 572 methods and 20 basis sets, it is found that the best mean absolute deviations (MADs) of density-functional theory (DFT) methods are 0.005 Å (shown by APFD/6-311++G**), 0.007 Å (B2PLYPD3(Full)/aug-cc-pVQZ), and 0.010 Å (revDSDPBEP86/aug-cc-pVQZ), while the best MADs of ab initio methods are 0.008 Å (BD(T)/aug-cc-pVTZ) and 0.016 Å (MP4/aug-cc-pVQZ). Moreover, the best MADs calculated by 54 selected methods in combination with 60 other basis sets (such as 6-311++G, 6-31++G(3d′f,3p′d), and UGBS1V++) are not better. Therefore, these bond lengths can be calculated with extremely high accuracy by some special methods and basis sets, and CCSD(T) is also not as good as expected because its best MAD is only 0.023 Å (CCSD(T)/aug-cc-pVQZ). [ABSTRACT FROM AUTHOR]

To investigate the bond behavior of ultra-high performance concrete (UHPC) and steel bar, central pull-out tests of 48 cube bond specimens were conducted, the ultimate tension, mean bonding stress, the average slip were evaluated. The influence of embedded length and diameter of reinforcing bar on bonding property of reinforced concrete in UHPC was discussed. The results show that the average ultimate bonding stress increases with the increase of bonding length. When the embedded length is 3d and 4d, the reinforcing bar is pulled out, and when the embedded length is 5d, the reinforcing bar is broken. When the diameter of reinforcing bar increased from 14 to 20 mm, the average ultimate bonding stress increased with increase of the ultimate tensile force. [ABSTRACT FROM AUTHOR]

Correlations between bond lengths d and the first ionization potentials of atoms and molecules are established on the basis of experimental data. Functional dependences are obtained for the series of compounds EX3 (E = N, P, As, Sb; X = F, Cl, Br, I) when Х or E are substituted. The difference between dependences with varied E or Х are explained by the differing effects on electron pairs of ion E3−. A way of estimating the values of ion radii RE for the elements N, P, As, and Sb is proposed. Interdependences of the values of radii of ions, their dipole moments, and refractions are discussed. The effect substituents X have on the values of radii RE is shown. The values of radii RE(3−) are evaluated for spherically symmetric ions. Linear dependences of radii RE(3−) and ionization potentials of the corresponding ions E3− and atoms of inert gases on their effective charges are established. [ABSTRACT FROM AUTHOR]

In this work, we apply the concept of tolerance factors (t) to pyrochlore solid solution, particularly when the B-site contains two different ions with different masses (as well as charge states) in the formula unit A 2 3 + B 3 + B ′ 5 + O 7 as in the present sample of A2BSbO7 (A3+ = Y, Dy, Gd, Bi; B3+ = Fe, Ga). We examine the previous tolerance factor and proposed a model of lattice constant (a) that depends only on the ionic radii RA, RB (= R F e + R (S b) 2 or R G a + R (S b) 2 ) and RO. Then we proposed an empirical tolerance factor (t), that depends only on the R A , R B and R O of the constituent atoms. We discuss the structural stability field and property features of mixed pyrochlore oxide compounds before measuring their structural data as for the case of perovskites. In the present work, we have proposed the empirical formula of lattice constant of A2BSbO7 (A3+ = Y, Dy, Gd, Bi; B3+ = Fe, Ga) of formula unit A 2 3 + B 3 + B ′ 5 + O 7 and hence find the tolerance factor, which predict the structural stability field and property features of mixed pyrochlore oxide compounds before measuring their structural data as for the case of perovskites. Caption: Errors (in %) between the calculated and experimental lattice constants. In the above figure, we shown that the errors (%) between the calculated and experimental lattice constants found from empirical lattice formula a = 8 3 1.4474357143 R A + R O - 0.42931 R A + R O 2 (R B + R O) and Rietveld analysis of powder diffraction data respectively. The error of predicting for the lattice constant by Brik and Srivastava (J Am Ceram Soc 95:1454–1460, 2012) is moderately higher than the error (≤ 0.523%) obtains by our model for mixed pyrochlore oxides. [ABSTRACT FROM AUTHOR]

We describe the synthesis of new series of thiazolo[4,5-d]thiopyrimidine derivatives 8 and 9 by reaction of 2-(phenylimino)-5-(thiophen-2-ylmethylene)thiazolidin-4-one 6 and 7 with thiourea in the presence of 5% KOH. We predict dipole moment, the geometry, bond angles and bond length by used DFT method and also used quantum chemical calculations to predict the reactivity and stability of new compounds through energy gap between HOMO and LUMO and DFT calculations give agree based on experimental elucidated of some newly compounds as IR, 1H-NMR, 13C-NMR. Compounds 8 and 9 were screened for in vitro antimicrobial activity Bacillus subtilis and Staphylococcus aureus as examples of bacterial strains and also antifungal activities. (Aspergillus flavus and Candida albicans). Compound 8 was showed higher activity than compound 9. [ABSTRACT FROM AUTHOR]

Regulating competitive reaction pathways to direct the selectivity of electrochemical CO 2 reduction reaction toward a desired product is crucial but remains challenging. Herein, switching product from HCOOH to CO is achieved by incorporating Sb element into the CuS, in which the Cu-S ionic bond is coupled with S-Sb covalent bond through bridging S atoms that elongates the Cu-S bond from 2.24 Å to 2.30 Å. Consequently, CuS with a shorter Cu-S bond exhibited a high selectivity for producing HCOOH, with a maximum Faradaic efficiency (FE) of 72 %. Conversely, Cu 3 SbS 4 characterized by an elongated Cu-S bond exhibited the most pronounced production of CO with a maximum FE of 60 %. In situ spectroscopy combined with density functional theory calculations revealed that the altered Cu-S bond length and local coordination environment make the *HCOO binding energy weaker on Cu 3 SbS 4 compared to that on CuS. Notably, a volcano-shaped correlation between the Cu-S bond length and adsorption strength of *COOH indicates that Cu-S in Cu 3 SbS 4 as double-active sites facilitates the adsorption of *COOH, and thus results in the high selectivity of Cu 3 SbS 4 toward CO., (© 2024 Wiley-VCH GmbH.)

Crystal field theory has been widely adopted to study the structure–property relationships in luminescent materials. It has the advantage of simplicity and clarity, i.e., the total crystal field splitting is reciprocally proportional to the 5th power of bond length. Yet this rule fails many times, especially in phosphors with low-symmetry sites. In order to provide an intact and practical framework of how to use crystal field theory, we address two main questions in this short review, i.e., how the 5th power rule is produced and why it fails. The regular octahedron potential is selected to show the procedure of crystal field calculations. Then the symmetry limitations on crystal field parameters are discussed considering the contribution from every ligand. After the set up of basic formula, two distinct cases, the reverse garnet effect and neutralization of cationic substitution on peak shifts are selected to show the effectiveness and validity of basic crystal field theory. It is hoped that this work could clarify some misconceptions and help the phosphor researchers in using crystal field theory.

In recent years, carbon fibre reinforced polymer (CFRP) laminates have conquered the structural rehabilitation market due to their ease and quick installation, high strength, anticorrosion properties, and other properties often repeated in the literature. The full potential of these high-strength elements can only be exploited by prestressing. However, the glued laminate joint is partially rigid, resulting in slippage that leads to premature debonding and failure. Therefore, anchoring of the laminate ends is required to stop or delay premature failure and/or perform prestressing. This article discusses the anchoring issues of CFRP laminates and guidelines for the development of anchoring systems. To achieve this goal, the laminate strip was bent, the required clamping forces were determined, possible cases of damage were identified, and individual stress concentrations were modelled. The methodology for calculating the anchor length and the pull-off force is also presented. [ABSTRACT FROM AUTHOR]

Qingbai wares, a distinguished type of ancient Chinese ceramics, are celebrated for the delicate blue-greenish white glazes. The scientific analysis of their microstructure and colouration mechanism has long been impeded by the exceedingly low iron content (∼1 wt%). This study employed a comprehensive multi-analytical approach to characterise the structural and optical properties of these glazes. Advanced experimental analyses, supported by ab initio calculations, shed light on the intricate roles of the valence states and coordination environments of iron in glaze colouration. Our results reveal that structural distortions in FeO 4 tetrahedra, evidenced by variations in Fe−O bond lengths, significantly impact light absorption, thereby influencing the glaze hues. This phenomenon is effectively explained by energy level splitting within the framework of ligand field theory. This research represents the first thorough investigation into the microstructure and colouration mechanism of Qingbai glazes, and provides new insights into the microstructure-property relationships in ancient ceramics. • First comprehensive study on the microstructure and colouration mechanism of Qingbai glazes. • Valence states and coordination environments of Fe ions play key roles in colouration. • Compression of FeO 4 tetrahedra with varying Fe−O bond lengths leads to a shift in light absorption. • Theoretical optical calculations match experimental results. • Ligand field theory explains colouration through energy splitting in electronic orbitals due to structural distortion. [ABSTRACT FROM AUTHOR]

Arsenic, ubiquitous in various industrial processes and consumer products, presents both essential functions and considerable toxicity risks, driving extensive research into safer applications. Our investigation, drawing from 7182 arsenic-containing molecules in the Cambridge Structural Database (CSD), outlines their diverse bonding patterns. Notably, 51% of these molecules exhibit cyclic connections, while 49% display acyclic ones. Arsenic forms eight distinct bonding types with other elements, with significant interactions observed, particularly with phenyl rings, O 3 and F 6 moieties. Top interactions involve carbon, nitrogen, oxygen, fluorine, sulfur, and arsenic itself. We meticulously evaluated average bond lengths under three conditions: without an R-factor cut-off, with R-factor ≤0.075, and with R-factor ≤0.05, supporting the credibility of our results. Comparative analysis with existing literature data enriches our understanding of arsenic's bonding behaviour. Our findings illuminate the structural attributes, molecular coordination, geometry, and bond lengths of arsenic with 68 diverse atoms, enriching our comprehension of arsenic chemistry. These revelations not only offer a pathway for crafting innovative and safer arsenic-based compounds but also foster the evolution of arsenic detoxification mechanisms, tackling pivotal health and environmental challenges linked to arsenic exposure across different contexts. [Display omitted] • Examining 7182 arsenic crystal structures in the CSD revealed eight bonding patterns, both cyclic and acyclic. • Arsenic's interactions with 68 elements, focusing particularly on bond lengths with As, C, F, N, O, and S, were identified. • Statistical analysis of bond lengths using R-factor thresholds contributes to the development of new arsenic-based drugs. • Future prospects in arsenic interactions for global medical and environmental applications were highlighted. [ABSTRACT FROM AUTHOR]

When the structures of 1342 molecules are optimized by 30 methods and 7 basis sets, there appear 289 (21.54%) problematic molecules and 112 (8.35%) failed ones. When 278 problematic molecules are compared, the best methods are BHandH and LC‐wPBE, while B97D, BP86, HFS, VSXC, and HCTH are very unreliable. When 179 problematic molecules are computed with larger basis sets, the smallest mean absolute deviation (MAD) of bond angle (2.3°) is shown by QCISD(T)/cc‐pVTZ, while the smallest MAD of bond length (0.021 Å), the best SUM1 (4.9 unit), and the best SUM2 (2.4 unit) are shown by DSDPBEP86(Full), DSDPBEP86, PBE1PBE‐D3, MP2, and MP2(Full) in combination with aug‐cc‐pVQZ, cc‐pVQZ, Def2QZVP, Def2TZVPP, and/or 6–311++G(3df,3pd). Very large basis sets, for example, larger than cc‐pVTZ usually have to be used to obtain very good structures and the performances of many density‐functional theory methods are encouraging. The best results may be the limit of modern computational chemistry. [ABSTRACT FROM AUTHOR]

It is shown that modeling the first oxygen‐oxygen peak in the neutron correlation function of a glass enables structural information about other correlations to be obtained, and the method is illustrated by application to a sodium silicate glass. The first O–O coordination number can be calculated from network theory, and sodium silicate crystal structures show that the mean O–O distance can be calculated from the Si–O distance, despite the distortion of the SiO4 tetrahedra. Modeling the O–O peak for a sodium silicate glass allows the Na‐O bond length distribution to be determined. For a binary glass with 42.5 mol% Na2O, it is found that the Na–O coordination number is 4.8(2) with an average bond length of 2.45 Å, and the Na–O bond lengths are more widely distributed than in sodium silicate crystal structures. Sodium ions are bonded mostly to non‐bridging oxygens (NBOs), and the Na–NBO coordination number may be four as in crystals. Sodium ions are also bonded to a smaller number of bridging oxygens (BOs). Contrary to previous reports, it is not concluded that Na–NBO bonds are shorter than Na–BO bonds, but instead that the Na–BO distribution is relatively narrow, whilst the Na–NBO distribution extends to both shorter and longer distance. The broad distribution of Na–O bond lengths arises from a relatively broad distribution of Na–NBO bond valences, subject to the overall requirement of charge balance. [ABSTRACT FROM AUTHOR]

In this review, the latest achievements in the field of multiply bonded organogermanium derivatives, mostly reported within the last two decades, are presented. The isolable Ge-containing analogues of alkenes, alkynes, 1,3-dienes, allenes, and vinylidenes are discussed, and for each class of unsaturated organogermanium compounds, the most representative examples are given. The synthetic approaches toward homonuclear multiply bonded combinations solely consisting of germanium atoms, and their heteronuclear variants containing germanium and other group 14 elements, both acyclic and cyclic, are discussed. The peculiar structural features and nonclassical bonding nature of the abovementioned compounds are discussed based on their spectroscopic and structural characteristics, in particular their crystallographic parameters (double bond length, trans-bending at the doubly bonded centers, and twisting about the double bond). The prospects for the practical use of the title compounds in synthetic and catalytic fields are also briefly discussed.

Spike anchors are one of the most promising techniques to prevent or delay debonding in FRP reinforcement sheets. There are several parameters affecting the anchors’ capacity, such as the embedment length and dowel angle. Regardless of the anchors’ capacity, their contribution to the overall strength of the anchored joint is affected by a larger number of variables, including the bonded length behind the anchors, the number and arrangement of the anchors, and the contact surface between the anchor fan and the FRP sheet. This paper presents experimental results of 10 tests conducted on concrete beams. In the tests, anchored joints reached peak loads up to 155% of those of unanchored, bonded joints. The main finding of the research is that the bond length in front of and behind the anchors affects both the peak load and the overall behaviour, with unbonded anchored joints exhibiting a poor behaviour and premature slippage of the anchor, without achieving its failure due to fibre rupture.

In the present work, nanocrystalline hausmannite Mn3O4:Ba thin films have been deposited on glass substrates by chemical spray pyrolysis (CSP). Then, we investigated the impact of Ba doping concentrations on the structural, morphological and optical properties. The structural characteristics were investigated by X-ray diffraction technique and clearly show the films have a spinel Mn3O4 polycrystalline structure, the degree of crystallinity was improved by increasing Ba concentrations in Mn3O4 matrix with crystallite size range of 15–33 nm. The lattice parameters, the unit cell volume and the (Mn-O) bond length of tetrahedral and octahedral sites, were varied by increasing Ba concentrations. SEM micrographs show that the films are homogeneous with nanoparticles dispersed on the surface with sizes range 30–132 nm. The optical properties were estimated by UV-Vis-NIR spectrophotometer and exhibited that the optical transmittance and band gap were improved by increasing Ba doping concentration. Empirical equations were suggested to estimate some correlated variables with excellent agreement with the experimental data. The optimum condition was recorded in films doped with 3% of Ba where a better crystallinity, a preferable surface morphology and outstanding optical properties have been achieved. [ABSTRACT FROM AUTHOR]

When the bond lengths of 11 molecules containing van der Waals bonds are optimized by 572 methods and 20 basis sets, it is found that the best mean absolute deviations (MADs) of density-functional theory (DFT) methods are 0.005 Å (shown by APFD/6-311++G**), 0.007 Å (B2PLYPD3(Full)/aug-cc-pVQZ), and 0.010 Å (revDSDPBEP86/aug-cc-pVQZ), while the best MADs of ab initio methods are 0.008 Å (BD(T)/aug-cc-pVTZ) and 0.016 Å (MP4/aug-cc-pVQZ). Moreover, the best MADs calculated by 54 selected methods in combination with 60 other basis sets (such as 6-311++G, 6-31++G(3d′f,3p′d), and UGBS1V++) are not better. Therefore, these bond lengths can be calculated with extremely high accuracy by some special methods and basis sets, and CCSD(T) is also not as good as expected because its best MAD is only 0.023 Å (CCSD(T)/aug-cc-pVQZ).

Comparing with the crystalline tungstate compounds, little work has been carried out and reported on the relation among the microstructure, W–O bond lengths, and characteristic Raman‐active vibration wavenumber of the molten tungstates, which allows us to diagnose and determine the structure of unknown clusters existing in and further predict the physicochemical properties of molten binary alkali tungstates. Raman spectra of an ensemble of eight model clusters were simulated in the present work by density functional theory (DFT) to establish the effect of the fine structures and W–Onb (non‐bridging oxygen) bond lengths of W–O complexes on the characteristic wavenumber of W–Onb Raman‐active vibration modes of the molten tungstates. Results show that the characteristic wavenumbers of the symmetric stretching vibration modes of W–Onb bonds increase almost linearly with the decreasing bond length. The characteristic wavenumbers of W–Onb symmetric stretching vibration modes generally follow [WO4]2− > [WO5]4− > [WO6]6− present in the melt simultaneously. The characteristic wavenumbers were also found to increase with the number of bridging oxygen for the same W–O complex. In situ Raman spectra of molten A2WnO3n + 1 (A = Li, Na, K; n = 1, 2, 3) were then measured in order to verify the correlation observed among the microstructure, W–O bond lengths, and characteristic Raman‐active vibration mode wavenumbers. The correlation was successfully applied to deconvolute the in situ Raman spectrum of the molten Na2W3O10. [ABSTRACT FROM AUTHOR]

Two distinct points on the potential energy curve (PEC) of a pairwise interaction, the zero‐energy crossing point and the point where the stretching force constant vanishes, allow us to anticipate the range of possible distances between two atoms in diatomic, molecular moieties and crystalline systems. We show that these bond‐stability boundaries are unambiguously defined and correlate with topological descriptors of electron‐density‐based scalar fields, and can be calculated using generic PECs. Chemical databases and quantum‐mechanical calculations are used to analyze a full set of diatomic bonds of atoms from the s‐p main block. Emphasis is placed on the effect of substituents in C−C covalent bonds, concluding that distances shorter than 1.14 Å or longer than 2.0 Å are unlikely to be achieved, in agreement with ultra‐high‐pressure data and transition‐state distances, respectively. Presumed exceptions are used to place our model in the correct framework and to formulate a conjecture for chained interactions, which offers an explanation for the multimodal histogram of O−H distances reported for hundreds of chemical systems. [ABSTRACT FROM AUTHOR]