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In order to investigate the deformation characteristics of interbedded weak expansive rocks in water immersion, the sandstone–mudstone interbedded structures were taken as the object of this study. A total of 27 sets of indoor immersion tests were designed with three influencing factors, namely, the layer thickness ratios of sandstone and mudstone (1:1, 2:1, 3:1), the occurrence of the rock layers (flat, oblique, and vertical), and the overburden loadings (0 kPa, 12.5 kPa, and 25 kPa). Tests were conducted to obtain the deformation time series data of the samples during the immersion loading process. Based on this, the influence pattern of each influencing factor on the sample deformation was analyzed individually. The results show that with the increase in overburden loading and rock inclination angle, the sample develops from expansion deformation to compression deformation. Changes in the layer thickness ratio will not change the deformation trend of the sample, and the decrease in the relative mudstone content will only reduce the absolute value of the sample's expansion and compression deformation. The deformation stability rate of the sample under load is 5~7 times that under no load. The increase in layer thickness ratio and rock inclination angle will lead to different degrees of attenuation of sample expansion force in the range of 8.91~38.68% and 51.00~58.83%, respectively. The research results of this paper can provide a meaningful reference for the design and maintenance of a high-speed railway subgrade in a weak expansive rock area with an interbedded structure. [ABSTRACT FROM AUTHOR]

In today's information era, collaborative filtering algorithms are widely used and their distinct knowledge discovery techniques can effectively address numerous issues. However, conventional collaborative filtering algorithms encounter cold-start and data sparsity issues, which restrict their performance and accuracy. The study selected the multi-feature method to improve the traditional collaborative filtering algorithm, and introduced gray correlation calculation and Bayesian probability for user preference analysis. A learning resource recommendation model based on collaborative filtering was developed by comparing the target user's characteristics with those of other users, calculating their similarity, selecting users with high similarity to the target user and forming a neighbor set. Using Bayesian probability and grey correlation to analyze user preferences in library systems can be well applied in book classification and recommendation problems in university libraries. The computing layer, which includes the collaborative filtering calculation stage and the group recommendation calculation stage, is the model's main functional component. The smaller the value of mean absolute error, the higher the prediction accuracy of the model. The mean absolute error value of the multi-feature collaborative filtering algorithm was inferior to the traditional collaborative filtering algorithm, indicating that the classification accuracy of the former is higher than that of the latter. When the training set to test set ratio steadily became bigger, the mean absolute error value reached the lowest and smoothest point at 80%. In dataset A, the minimum mean absolute error values of multi-feature collaborative filtering and collaborative filtering were 0.765 and 0.809. Compared with traditional filtering algorithms, the mean absolute error value has decreased by 0.044. In dataset B, the mean absolute error values of multi-feature collaborative filtering and collaborative filtering were 0.796 and 0.836. Compared with traditional filtering algorithms, the mean absolute error value has decreased by 0.040. In dataset C, the minimum mean absolute error values of multi-feature collaborative filtering and collaborative filtering were 0.815 and 0.848. Compared with traditional filtering algorithms, the mean absolute error value has decreased by 0.033. When the accuracy was the highest; the mean absolute error value was the smallest at the grey correlation, which means that the technique improves the reliability of the recommendations compared with other methods. This means that the method has a positive impact on the accuracy of the recommendations compared to other methods. Grey correlation degree can comprehensively consider the interrelationships between multiple factors, handle uncertain and incomplete information, and explore potential user needs and behavior patterns. The implementation of the grey correlation degree has transformed the collaborative filtering algorithm into a group filtering algorithm, thereby enhancing its precision. The research on book classification and recommendation in university libraries, which enhances the group filtering algorithm, can address a range of issues such as improving classification accuracy, augmenting recommendation diversity, enhancing library management efficiency among others. This, in turn, enables more precise book recommendations to users. [ABSTRACT FROM AUTHOR]

Background: Diffusion-weighted imaging (DWI) is a novel imaging technique with a growing application in onco- imaging. This modality evaluates the diffusion of water molecules in various tissues, which is restricted in hypercellular regions such as malignant tissue. Apparent diffusion coefficient (ADC) is a method that can quantify the degree of restriction in tissues and can have diagnostic roles in the characterization of hepatic lesions. The ratio of ADC values between a lesion and the background liver can potentially negate these external factors and provide a more accurate representation of change in the diffusion with respect to normal tissue. Aim: Our study aimed to investigate the usefulness of ADC ratio of a solid liver lesion to liver parenchyma to discriminate between benign and malignant lesions. Methods: This was a cross sectional study conducted on all patients with hepatic solid focal lesion (benign or malignant), starting from 10-2019 to 4-2020. All patients were subjected to: Full history taking including, Radiological investigations, and Laboratory investigations. Result: There was significant difference between benign and malignant group as regards lesion: liver ADC ratio. Conclusion: Lesion to background liver ADCratio is superior in discriminating between benign and malignant focal lesions compared to absolute ADC values of the hepatic lesions. With increasing ADCratio, there is a trend towards benignity. A cut off of ADCratio below 0.9 reflected malignancies while ADCratio above 1.5 reflected benign aetiology. These cut offs can be validated further with further studies with larger number of individual malignant and benign lesions. [ABSTRACT FROM AUTHOR]

Purpose. To determine the general patterns in the formation of the sorption capacity of coal and the natural regional methane content of coal beds using a quantitative indicator – the relative gradient of gas content. Methodology. To determine the sorption capacity of coal, the authors used the well-known “volumetric method” and the method of EPR-spectroscopy (electron paramagnetic resonance). We used the results obtained during geological exploration to analyze the natural gas content of coal beds. The determination of natural gas content was carried out using special gas-core-samplers and formation testers. Methods of mathematical statistics were used to process experimental data. Findings. According to experimental data regarding the sorption methane-bearing capacity and natural gas content of Donbas coal beds, we carried out the analysis, statistical processing, and generalization of the obtained results. A regular change in the relative gradient of coal beds’ methane content has been established for the entire Donbas as a whole. The values of relative gradients for coals of various grades naturally decrease with increasing stratification depth and also naturally decrease in each depth interval from low-metamorphosed (grade D) coal to highly-metamorphosed one. Based on the approximation results, the corresponding equations were obtained for each grade of coal metamorphism from gas to-anthracite (A). Originality. New indicators have been proposed – the relative gradient of sorption methane-bearing capacity and the relative gradient of gas content, which allow comparison of these characteristics measured in absolute values (cm³ /g, m³ /t) for individual coal beds of different grades of metamorphism, at different depths and lying in different geological conditions. It has been proven that the sorption capacity of coal matter determines the natural regional (background) methane content of coal beds, and naturally, according to a hyperbolic dependence, decreases with increasing stratification depth and also naturally decreases in each of the depth intervals from low-metamorphosed coal (grade D) to highly metamorphosed one (grade A), with a relative gradient that asymptotically approaches to 1 at pressures above 6 MPa. Practical values. The obtained dependences of the relative gradient of gas content on depth and gas pressure for various grades of metamorphism can be used to predict the natural regional (background) gas content of coal beds by determining the maximum sorption capacity and calculating the desired depth or pressure. [ABSTRACT FROM AUTHOR]

In this paper, two new iterative methods for solving generalized absolute value equations (GAVEs) are proposed and investigated using the single-step iteration (SSI) approach. The proposed iterative methods are Picard-SSI and nonlinear SSI-like methods. In the implementation of the Picard-SSI method, we have used the SSI method as an inner solver. The convergence of the proposed method for solving GAVE is analyzed under reasonable constraints. Several numerical examples are given to illustrate the efficiency and implementation of the proposed methods. [ABSTRACT FROM AUTHOR]

Linear ARMA model fitting requires to select the order of the model as accurately as possible. Many past studies are based on portmanteau tests, originally derived for the white noise hypothesis, but applied to the autocorrelations of the estimated residuals, and employ sums of the scaled squares of the first d residual autocorrelations. An automatic choice of d was proposed by Escanciano and Lobato (J Econom 151:140–149, 2009) based on the largest (in absolute value) residual autocorrelation. Such maximal autocorrelation may be itself employed as a test statistic, and Baragona et al. (Test 31:675–698, 2022) proposed white noise tests based on a bivariate statistic consisting of both the portmanteau and the largest autocorrelation. However, the derivation of the asymptotic null distribution requires asymptotic independence of the autocorrelation estimates and this is not true when they are computed on the residuals of a fitted ARMA model. Therefore, we propose to use a linear transformation of the estimated residual autocorrelation in order to achieve independence, in the same spirit as recursive residuals in regression. Monte Carlo experiments are performed for comparing the effectiveness of our new method to the Escanciano Lobato and a more classical portmanteau test. We find that the two data-driven tests are approximately equivalent if non negligible residual autocorrelation is found only at the first lags, while our test is more powerful if autocorrelations at larger lags arises. [ABSTRACT FROM AUTHOR]

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In this paper, a signal model and a mathematical analysis of an efficient approach are derived to acquire the approximate magnitude of a complex signal by inducing a pre-biased or a pre-scaled factor in the design criteria. According to the deductive results, the pre-biased or pre-scaled factor can be 2∼3 dB, which is determined through its application. The numerical evaluations show that the mean square error (MSE) of the proposed efficient approach for the random signal is around −33 dB. Based on the design templates for the considered approaches, the occupied areas of the proposed type-1 and -2 approaches are merely 0.13 and 0.09 times the area of the direct-method, respectively. As a result, the proposed efficient approach is certainly a cost-efficient method for obtaining the approximate magnitude of a complex signal. [ABSTRACT FROM AUTHOR]

The determinants of { ± 1 } -matrices are calculated via the oriented hypergraphic Laplacian and summing over incidence generalizations of vertex cycle-covers. These cycle-covers are signed and partitioned into families based on their hyperedge containment. Every non-edge-monic family is shown to contribute a net value of 0 to the Laplacian, while each edge-monic family is shown to sum to the absolute value of the determinant of the original incidence matrix. Simple symmetries are identified as well as their relationship to Hadamard's maximum determinant problem. Finally, the entries of the incidence matrix are reclaimed using only the signs of an adjacency-minimal set of cycle-covers from an edge-monic family. [ABSTRACT FROM AUTHOR]

The energy of a simple graph G is defined as the sum of the absolute values of eigenvalues of the adjacency matrix of G. For a complex matrix M the spread of M is the maximum absolute value of the differences between any two eigenvalues of M. Thus if λ 1 , ... , λ n are the eigenvalues of M , then the spread of M is max 1 ≤ i , j ≤ n ⁡ | λ i − λ j |. The spread of a graph G is defined as the spread of its adjacency matrix and is denoted by s (G). The inertia of G is an integer triple (n + , n − , n 0) specifying the numbers of positive, negative and zero eigenvalues of the adjacency matrix of G. In this paper we find some bounds for energy of graphs in terms of some parameters of graphs such as rank, inertia and spread of graphs. We find some bounds for spread of graphs and matrices that improve the previous bounds. In particular, we show that if G is a graph with m edges and inertia (n + , n − , n 0) , then s (G) ≥ 2 m (n + + n −) n + n − and the equality holds if and only if G = r K s ∪ t K 1 or G = r K p , ... , p ︸ q ∪ t K 1 or G = r 1 K a 1 , b 1 ∪ ⋯ ∪ r h K a h , b h , for some non-negative integers r , s , t , p , q and r 1 , a 1 , b 1 , ... , r h , a h , b h such that a 1 b 1 = ⋯ = a h b h , p ≥ 2 and q ≥ 3. [ABSTRACT FROM AUTHOR]

Profile control technology as an effective technology has been widely used in oilfield production in recent years. However, the effect of chemical injection in profile control process on the stability of produced liquid is not clear. Therefore, based on the existing technology, this paper studied the influence of residual profile control agent (alkali, surfactant, polymer) in produced liquid on the stability of produced liquid with the subject of an oilfield in the South China Sea(EP). The results showed that due to the interaction between the residual agent and crude oil, the residual drug dose in the produced fluid should be controlled at 2-3 × 10−4wt, and the absolute value of zeta potential increases the fastest, the absolute value of zeta potential is within 5.5 mV and the interfacial tension is greater than 1.75 mN/m. The diameter of oil droplets in water reaches the maximum value of 12.31 μm, and the oil content in water and the water content in oil are lower than 50%. [ABSTRACT FROM AUTHOR]

Given a rooted tree T with vertices u 1 , u 2 , ... , u n , the level matrix L (T) of T is the n × n matrix for which the (i , j) -th entry is the absolute difference of the distances from the root to v i and v j. This matrix was implicitly introduced by Balaji and Mahmoud (2017) as a way to capture the overall balance of a random class of rooted trees. In this paper, we present various bounds on the eigenvalues of L (T) in terms of other tree parameters, and also determine the extremal structures among trees with a given order. Moreover, we establish bounds on the multiplicity of any eigenvalue in the level spectrum and show that the bounds are best possible. Furthermore, we provide evidence that the level spectrum can characterise some trees. In particular, we provide an affirmative answer to a very recent conjecture on the level energy (sum of absolute values of eigenvalues). [ABSTRACT FROM AUTHOR]

We establish a Pythagorean theorem for the absolute values of the blocks of a partitioned matrix. This leads to a series of remarkable operator inequalities. For instance, if the matrix \mathbb {A} is partitioned into three blocks A,B,C, then \begin{gather*} |\mathbb {A}|^3 \ge U|A|^3U^* + V|B|^3V^*+ W|C|^3W^*,\\ \sqrt {3} |\mathbb {A}| \ge U|A|U^* + V|B|V^*+ W|C|W^*, \end{gather*} for some isometries U,V,W, and \begin{equation*} \mu _4^2(\mathbb {A}) \le \mu _3^2(A) +\mu _2^2(B) + \mu _1^2(C) \end{equation*} where \mu _j stands for the j-th singular value. Our theorem may be used to extend a result by Bhatia and Kittaneh for the Schatten p-norms and to give a singular value version of Cauchy's Interlacing Theorem. [ABSTRACT FROM AUTHOR]

Because of the complex composition of tungsten tailings and low tin content in the tailings, the traditional titration analysis method and colorimetric analysis method are easily interfered by tungsten, copper and other elements, resulting in unsatisfactory results. In this paper, sodium peroxide was used to melt tungsten tailings sample, water leaching, hydroxide precipitation separation of most of the interference elements, supernatant liquid acidification, atomic fluorescence spectrometry was used for determination, which solved the problem of insufficient sensitivity, eliminated the influence of coexisting tungsten, copper and other elements on the determination of tin, and established the accurate determination of tin in tungsten tailings by atonic fluorescence spectrometry. At the same time, the influences of sample treatment method, determination of solution acidity, thiourea-ascorbic acid mixed reducing agent and potassium borohydride concentration on the determination of tin by atonic fluorescence spectrometry were investigated, and the determination parameters of atomic fluorescence spectrometry were optimized. The relative standard deviation (RSD, n = 7) of the determination of tin was less than 5%. The tungsten ore composition analysis standard substance with tungsten content similar to that in tungsten tailings was used for method verification. The absolute value of the relative error was LESS than 5%, and the recovery rate was 94.5%-108%. This method for determining in in tungsten tailings has the advantages of simple operation, high sensitivity, less interference, high accuracy and low cost. [ABSTRACT FROM AUTHOR]

Laminar flame speed is commonly measured using the spherically expanding flame technique. The non-ideal shape of the initial flame kernel may have a significant influence on the subsequent flame propagation. In the present study, the propagation evolution of expanding ellipsoidal flame initiated from an ellipsoidal flame kernel was simulated with the propagation speed following the linear stretch relation. The effects of two components for the total stretch rate, i.e. curvature stretch and tangential stretch, were investigated. Different from the ideal spherical flame, which excludes the effect of tangential flow, tangential stretch can be negative and can be on the same order as the curvature stretch during the early stage of flame propagation. With flame expanding outwardly, the absolute value of tangential stretch decreases. The relative decrement of tangential stretch is more obvious if the flame speed is faster. The present results imply that large initial flame radius data should be used for laminar flame speed extrapolation when the shape of the flame significantly deviates from an ideal sphere. [ABSTRACT FROM AUTHOR]

A new steganographic method by pixel-value differencing (PVD) using general quantization ranges of pixel pairs' difference values is proposed. The objective of this method is to provide a data embedding technique with a range table with range widths not limited to powers of 2, extending PVD-based methods to enhance their flexibility and data-embedding rates without changing their capabilities to resist security attacks. Specifically, the conventional PVD technique partitions a grayscale image into 1 × 2 non-overlapping blocks. The entire range [0, 255] of all possible absolute values of the pixel pairs' grayscale differences in the blocks is divided into multiple quantization ranges. The width of each quantization range is a power of two to facilitate the direct embedding of the bit information with high embedding rates. Without using power-of-two range widths, the embedding rates can drop using conventional embedding techniques. In contrast, the proposed method uses general quantization range widths, and a multiple-based number conversion mechanism is employed skillfully to implement the use of non-power-of-two range widths, with each pixel pair being employed to embed a digit in the multiple-based number. All the message bits are converted into a big multiple-based number whose digits can be embedded into the pixel pairs with a higher embedding rate. Good experimental results showed the feasibility of the proposed method and its resistance to security attacks. In addition, implementation examples are provided, where the proposed method adopts non-power-of-two range widths and employs multiple-based number conversion to expand the data-hiding and steganalysis-resisting capabilities of other PVD methods. [ABSTRACT FROM AUTHOR]

We generate new evidence on disagreement among traders in the S&P 500 options market from high-frequency intraday price and volume data. Inference on disagreement is based on a model where investors observe public information but agree to disagree on its interpretation; disagreement among investors is captured by the volume–volatility elasticity. For options, there are two natural variables related to disagreement: moneyness and tenor, which we relate to disagreement about the distribution of the market index at different quantiles and times. The estimated volume–volatility elasticity equals unity for options near the money and close to expiration, which is consistent with the case of no disagreement among investors. In contrast, the elasticity estimates decrease with increases in the absolute value of moneyness, indicating investors have a higher disagreement about rare events. Likewise, the elasticity decreases with increases in tenor, implying higher investors' disagreement about more distant events. [ABSTRACT FROM AUTHOR]

Photothermal excitation based on thermoelastic mechanisms is widely used in non-destructive testing, precision operations, and driving micro-resonators. The narrow drive bandwidth of the high vibration mode in photothermal excitation limits its application to multi-mode drives. Controlling the laser's irradiation position is an effective solution. In this study, we build a theoretical model to achieve selective and efficient excitation of different flexural vibration modes of beams with different supports. The model can be extended to other thermal and physical boundaries, which is validated by numerical simulations and experimental results. The results show that higher modes with complex periodic shapes can be efficiently excited by focusing the laser at the peak of the absolute value of the second derivative of the flexural mode while focusing the laser at the inflection point of the mode shape will result in extremely small amplitudes. Our study indicates that the thermal gradient plays a vital role in the oscillation of the beam. The conventional view assumes that the resonance of the photo-thermal excitation beam is caused by the local expansion and contraction of the material, which cannot completely explain the dependence principle of the photothermal vibration on the laser irradiation position. To investigate the mechanism of beam resonance under laser excitation, three excitation modes, unidirectional excitation, bidirectional in-phase excitation, and bidirectional anti-phase excitation, were established, and the conversion process of optical energy to mechanical energy under laser excitation was analyzed. These results provide new options for optimal excitation and multi-mode energy flow control in photothermal driving. [ABSTRACT FROM AUTHOR]

In this paper, an analytical exact form of the ramp function is presented. This seminal function constitutes a fundamental concept of the digital signal processing theory and is also involved in many other areas of applied sciences and engineering. In particular, the ramp function is performed in a simple manner as the pointwise limit of a sequence of real and continuous functions with pointwise convergence. This limit is zero for strictly negative values of the real variable x, whereas it coincides with the independent variable x for strictly positive values of the variable x. Here, one may elucidate beforehand that the pointwise limit of a sequence of continuous functions can constitute a discontinuous function, on the condition that the convergence is not uniform. The novelty of this work, when compared to other research studies concerning analytical expressions of the ramp function, is that the proposed formula is not exhibited in terms of miscellaneous special functions, e.g., gamma function, biexponential function, or any other special functions, such as error function, hyperbolic function, orthogonal polynomials, etc. Hence, this formula may be much more practical, flexible, and useful in the computational procedures, which are inserted into digital signal processing techniques and other engineering practices.

Niche and dispersal‐based processes govern freshwater communities, such as aquatic insects, shaping their distribution and establishment in the environment. So, we aimed to address the relative influence of niche and dispersal‐based processes on Odonata diversity in Amazonian freshwater systems, and the influence of species dispersal functional traits on their longitudinal and latitudinal ranges. We used the Dispersal‐Niche Continuum Index (DNCI) to test (i) regions more distant would present a prevalence of dispersal‐based processes, and (ii) different patterns would come from the two Odonata suborders; and by applying generalised linear models, we tested (iii) dispersal‐related functional traits from the suborders would influence latitudinal and longitudinal midpoints of the species. We found that more distant regions had lower values of pairwise Dispersal–Niche Continuum, mainly for Zygoptera, corroborating our first hypothesis. Moreover, Zygoptera also presented the lowest absolute values of Dispersal–Niche Continuum and Anisoptera presented a joint influence of niche and dispersal‐based processes, agreeing with our second hypothesis. Only Zygoptera presented a significant association between dispersal functional traits and longitudinal midpoints, corroborating our third hypothesis. Our results indicated a prevalence of dispersal‐related processes for Zygoptera, which can be explained by massive geographical barriers, such as the rivers, and their narrow physiological and ecological tolerance. Moreover, dispersal‐related traits demonstrated significant influence on longitudinal midpoints of Zygoptera, a scenario that the presence of the rivers may explain. A better understanding of the prevalent predictors of the species and how their dispersal ability governs their distribution has conservational implications. [ABSTRACT FROM AUTHOR]

Head movements that are synchronized with musical rhythms often emerge during musical activities, such as hip hop dance. Although such movements are known to affect the meter and pulse perception of complex auditory rhythms, no studies have investigated their contribution to the performance of sensorimotor synchronization (SMS). In the present study, participants listened to syncopated auditory rhythms and flexed their dominant hand index finger in time with the perceived pulses (4/4 meters). In the first experiment (Exp. 1), the participants moved their heads via voluntary neck flexion to the pulses in parallel with finger SMS (Nodding condition, ND). This performance was compared with finger SMS without nodding (Without Nodding condition, WN). In the second experiment (Exp. 2), we investigated the specificity of the effect of head SMS on finger SMS confirmed in Exp. 1 by asking participants to flex their bilateral index fingers to the pulses (Bimanual condition, BM). We compared the performance of dominant hand finger SMS between the BM and ND conditions. In Exp. 1, we found that dominant hand finger SMS was significantly more stable (smaller standard deviation of asynchrony) in the ND versus WN condition (p < 0.001). In Exp. 2, dominant hand finger SMS was significantly more accurate (smaller absolute value of asynchrony) in the ND versus BM condition (p = 0.037). In addition, the stability of dominant hand finger SMS was significantly correlated with the index of phase locking between the pulses and head SMS across participants in the ND condition (r = -0.85, p < 0.001). In contrast, the stability of dominant hand finger SMS was not significantly correlated with the index of phase locking between pulses and non-dominant hand finger SMS in the BM condition (r = -0.25, p = 0.86 after multiple comparison correction). These findings suggest that SMS modulation depends on the motor effectors simultaneously involved in synchronization: simultaneous head SMS stabilizes the timing of dominant hand finger SMS, while simultaneous non-dominant hand finger SMS deteriorates the timing accuracy of dominant hand finger SMS. The present study emphasizes the unique and crucial role of head movements in rhythmic behavior. [ABSTRACT FROM AUTHOR]

Ratios ms/md and mu/md of the light quark masses have been determined from expressions for squared masses of pseudoscalar mesons and obtained with an accuracy of the second order in chiral symmetry breaking. The fit of the theoretical expressions for and to their phenomenological values leads to a functional relation between the ratios ms/md and mu/md, which is described by a third-order curve. The application of the lattice calculation result ms/mud = 27.23(10), where mud = (mu + md)/2, reported by the flavor lattice averaging group (FLAG) for the case of four quark flavors provides an additional constraint, which significantly reduces the error (~2%) for the ratio mu/md = 0.455(8). The absolute values of the quark masses have been then obtained. [ABSTRACT FROM AUTHOR]

The aim of this paper was to investigate intumescent coatings based on polyfurfuryl alcohol (PFA) resin as a binder benefiting from high char yield and low smoke emission. To this end, the coatings composition in terms of PFA binder resin, long oil alkyd plasticizing resin, TiO2 pigment, and flame-retardant additives (FR) was changed as input parameters according to a mixture design-of-experiments. The corresponding changes in the backside temperature of mild steel substrate (Tb), residual char expansion ratio, limiting oxygen index, and char residue (wt% @1000 °C) were studied as the response variables describing fire performance characteristics of the coatings. The results showed that the backside temperature of the plate increased and the expansion ratio decreased with increasing in the alkyd resin concentration. Also, the flame-retardant efficiency of coatings strongly depends on the content of FR additives. When the content of PFA and alkyd resin was increased at a high level (35 and 4 wt%, respectively), the Tb of the coated plates reached 415 °C rapidly, due to the cracking of the coating and the lower concentration of FR additives. However, the formula with higher FR content, i.e., 68 wt%, showed the lowest Tb value ca. 128 °C. Flame-retardant characteristics directly depended on the expansion ratio of the coatings and the morphology of the char layer remaining on the substrate after the flame test; therefore, coatings with a higher expansion ratio showed lower backside temperature. The findings were supported by examining of the remaining char morphology after a flame test by optical microscopy and validated by comparing the predicted and actual responses for optimization. The value of absolute relative deviation was obtained in the range of 1.6–7.9, which indicates a good agreement between the proposed and experimental results. [ABSTRACT FROM AUTHOR]

Buckling may cause drill string damage or even drilling failure. For the 3 000-m-long horizontal section drill string, a simplified analysis model of drill string in horizontal well is established, and the dynamic response results of axial displacement, angular displacement and contact force are obtained. When buckling, the closer the position of drill string is to the bottom, the later the buckling time, the smaller the buckling deformation degree, the slower the growth rate of axial displacement, and the smaller the attenuation degree of angular displacement and contact force amplitude. After buckling, drill string undergoes tensile deformation and eventually remains stable in the tensile state. After stabilization, from the top of drill string to the bottom of drill string, axial displacement increment increases first, then remains unchanged and then decreases, and the relative torsion angle between different positions gradually decreases. The drill string is always in horizontal contact with the wellbore, resulting in the same contact force values at different locations. The change of well inclination angle does not affect the change law of displacement and contact force. The absolute value of angular displacement is negatively correlated with the change of well inclination angle, and the value of axial displacement increment and contact force is positively correlated with the change of well deviation angle, but the value of contact force is quite close. The research results can provide reference for alleviating the buckling of drill string in horizontal wells. [ABSTRACT FROM AUTHOR]

A double-volute centrifugal pump is a very important pump type; the internal flow field of a centrifugal pump will change drastically during the transition process of power failure, which will affect the safety and stability of the pump's operation. In this paper, the CFD numerical simulation method is used, and the UDF procedure is developed to realize the continuous update of the impeller speed at each time step. The working parameters, such as the torque and flow rate at the instantaneous moment, are obtained through the sequential iteration of each small step, and a numerical simulation of the power-off transient is carried out on a double-volute centrifugal pump; additionally, the changes in the external characteristic parameters and the internal flow field of the centrifugal pump are analyzed in detail. The results show that the double-volute centrifugal pump experienced four different modes after power failure, namely pump mode, braking mode, turbine mode, and runaway mode, and the absolute values of the runaway speed and runaway flow rate are 1.465 times and 1.21 times the initial values, respectively. Through the analysis of the flow field in different regions, the change processes of the generation, development, and disappearance of the vortex at each position of the centrifugal pump are obtained, and the change and development processes of the internal velocity gradient of the centrifugal pump are obtained. In addition, it is found that the high-speed area located in the second volute runner is larger than that of the first volute runner because the second volute runner is shorter and narrower than the first volute runner. [ABSTRACT FROM AUTHOR]

Research on cardiovascular diseases using CT-derived strain is gaining momentum, yet there is a paucity of information regarding reference standard values beyond echocardiography, particularly in cardiac chambers other than the left ventricle (LV). We aimed to compile CT-derived strain values from the four cardiac chambers in healthy adults and assess the impact of age and sex on myocardial strains. This study included 101 (mean age: 55.2 ± 9.0 years, 55.4% men) consecutive healthy individuals who underwent multiphase cardiac CT. CT-derived cardiac strains, including LV global and segmental longitudinal, circumferential, and transverse strains, left atrial (LA), right atrial (RA), and right ventricle (RV) strains were measured by the commercially available software. Strain values were classified and compared by their age and sex. The normal range of CT-derived LV global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS) were −20.2 ± 2.7%, −27.9 ± 4.1%, and 49.4 ± 12.1%, respectively. For LA, reservoir strain, pump strain, and conduit strain were 28.6 ± 8.5%, 13.2 ± 6.4%, and 15.5 ± 8.6%, respectively. The GLS of RA and RV were 27.9 ± 10.9% and −22.0 ± 5.7%, respectively. The absolute values of GLS of RA and RV of women were higher than that in men (32.4 ± 11.4 vs. 24.3 ± 9.1 and −25.2 ± 4.7 vs. −19.4 ± 5.0, respectively; p<0.001, both). Measurement of CT-derived strain in four cardiac chambers is feasible. The reference ranges of CT strains in four cardiac chambers can be used for future studies of various cardiac diseases using the cardiac strains. [ABSTRACT FROM AUTHOR]

Employing functional building units with microscopic second‐order NLO response has been proposed to explore high performance NLO materials. Herein, structural, electronic and optical properties of non‐centrosymmetric molybdenyl carbonate Cs3MoO4(HCO3) with NLO active functional units have been examined based on density functional theory. Theoretical results are consistent with experimentally mentioned data, confirming the reliable method. Detailed geometric structure, electronic attributes, linear optical properties, and nonlinear optical properties of Cs3MoO4(HCO3) are provided. Analysis of structures, compositions of bands and plots of charge density suggest that asymmetric functional building units [MoO4] and [HCO3] exhibit varying degrees of second‐order Jahn‐Teller distortions, and therefore have a significant impact on the electronic structure and optical properties of Cs3MoO4(HCO3). Maximum absolute value of SHG coefficients at 1064 nm is 0.671 pm/V for d15, which is nearly twice as much as that of KDP. Further researches are needed in future to validate and enhance optical anisotropy characteristic of Cs3MoO4(HCO3) for satisfying the phase matching conditions. Analysis results indicate that microscopic origins of SHG response in Cs3MoO4(HCO3) are complicated, such as geometric environment, induced polar asymmetric functional building units, and electronic properties. Continuous research on structure‐property relationship of NLO materials is needed for exploring more competitive NLO materials. [ABSTRACT FROM AUTHOR]

The SOR-like iteration method for solving the system of absolute value equations of finding a vector x such that A x - | x | - b = 0 with ν = ‖ A - 1 ‖ 2 < 1 is investigated. The convergence conditions of the SOR-like iteration method proposed by Ke and Ma (Appl. Math. Comput., 311:195–202, 2017) are revisited and a new proof is given, which exhibits some insights in determining the convergent region and the optimal iteration parameter. Along this line, the optimal parameter which minimizes ‖ T ν (ω) ‖ 2 with T ν (ω) = | 1 - ω | ω 2 ν | 1 - ω | | 1 - ω | + ω 2 ν and the approximate optimal parameter which minimizes an upper bound of ‖ T ν (ω) ‖ 2 are explored. The optimal and approximate optimal parameters are iteration-independent, and the bigger value of ν is, the smaller convergent region of the iteration parameter ω is. Numerical results are presented to demonstrate that the SOR-like iteration method with the optimal parameter is superior to that with the approximate optimal parameter proposed by Guo et al. (Appl. Math. Lett., 97:107–113, 2019). [ABSTRACT FROM AUTHOR]

In this paper, we focus on solving the generalized absolute value equations (GAVE). We present a new method named as modulus-based block triangular splitting iteration (MBTS) method based on the block matrix structure resulting from the transformation of the GAVE into two equations. This method is developed by decomposing the matrix into diagonal and triangular matrices, as well as applying a series of suitable combination and modification techniques. The advantage of the MBTS method is that it is not necessary to solve the inverse of the coefficient matrix of the linear equation system during each iteration, which greatly improves the computational speed and reduces its storage requirements. In addition, we present some convergent theorems proving by different techniques and the estimate of the required number of iteration steps. Furthermore, in the accompanying corollaries, we provide some estimations for choosing appropriate parameter values. Finally, we validated the effectiveness and efficiency of our newly developed method through two numerical examples of the GAVE. [ABSTRACT FROM AUTHOR]

Despite its many advantages, the glass interposer in 2.5D package has been largely restricted in use due to the formation of cracks in through-glass-via (TGV) structure. In this study, we systematically demonstrated the cracks in TGVs can be reduced or eliminated by selecting the appropriate glass material, annealing temperature, and Cu via structure. The energy release rate (ERR) of the circumferential and radial crack in the glass was analyzed using numerical simulation. The ERR of five different glasses which are fused silica, aluminosilicate, borosilicate, Gorilla, and ceramic glass was analyzed during annealing process. The ERR values of various glasses are ranked from highest to lowest as follows: fused silica, aluminosilicate, borosilicate, Gorilla, and ceramic glass. The ERR of the ceramic glass is 4.4 times lower than that of the fused silica glass. The overall ERR value of the ceramic glass is very low (less than 2 J/m2), unlikely to crack even when exposed to water. The types of TGV structure and Cu pad also affect crack formation. The hollow TGV with the Cu pad showed the lowest ERR. We also investigated the TGV crack formation when the 2.5D package with the glass interposer was subjected to thermal cycling condition. Even though the absolute ERR value is not large compared to that which occurred during the annealing process, cracks can still occur during thermal cycling. This study will provide a useful guidance to prevent thermomechanical cracks and ensure the reliability of the 2.5D package. [ABSTRACT FROM AUTHOR]

Based on data from mid-latitude ionospheric stations at close corrected geomagnetic latitudes, the properties of the variability in the F2 layer peak density (NmF2) at different longitudes were analyzed during increased (48 > ap(τ) > 27) and high (ap(τ) > 48) geomagnetic activity, where ap(τ) is the weighted average ap-index of this activity. The standard deviation σ of Nm fluctuations with respect to the quiet level and the average shift of these fluctuations xave were used as characteristics of this variability. It was found that at all analyzed stations, the variance σ 2 for increased geomagnetic activity is greater than for quiet conditions but hardly differs from σ 2 for high geomagnetic activity. For all analyzed cases, the average shift xave < 0, and for high geomagnetic activity, the absolute value of xave is greater than for increased geomagnetic activity. The difference in xave values between the analyzed stations is quite large. One reason for this difference may be related to the dependence of xave on geomagnetic latitudes. Approximations of the geomagnetic field by the tilted dipole (TD), eccentric dipole (ED), or using corrected geomagnetic (CGM) coordinates were used to select these latitudes. It was found that the dependence of xave on ED latitude is more accurate than the dependence of xave on TD latitude and, moreover, the dependence of xave on CGM latitude. Therefore, ED latitudes, and not CGM latitudes, are optimal for accounting for storm effects on the F2 layer peak density at mid-latitudes. This conclusion has apparently been obtained for the first time. [ABSTRACT FROM AUTHOR]

In this study, an integral identity is given in order to present some Hermite–Hadamard–Mercer-type inequalities for functions whose powers of the absolute values of the third derivatives are convex. Several consequences and three applications to special means are given, as well as four examples with graphics which illustrate the validity of the results. Moreover, several Hermite–Hadamard–Mercer-type inequalities for fractional integrals for functions whose powers of the absolute values of the third derivatives are convex are presented. [ABSTRACT FROM AUTHOR]

Deligne proved in [Extensions centrales non résiduellement finies de groupes arithmetiques, C. R. Acad. Sci. Paris 287 (1978) 203–208] (see also 7.1 in [R. Hill, Fractional weights and non-congruence subgroups, in Automorphic Forms and Representations of Algebraic Groups Over Local Fields, eds. H. Saito and T. Takahashi, Surikenkoukyuroku Series, Vol. 1338 (2003), pp. 71–80]) that the weights of Siegel modular forms on any congruence subgroup of the Siegel modular group of genus g > 1 must be integral or half integral. Actually he proved that for a system v (M) of complex numbers of absolute value 1 v (M) det (C Z + D) r (r ∈ ℝ) (0. 1) can be an automorphy factor only if 2 r is integral. We give a different proof for this. It uses Mennicke's result [Zur Theorie der Siegelschen Modulgruppe, Math. Ann. 159 (1965) 115–129] that subgroups of finite index of the Siegel modular group are congruence subgroups and some techniques from [Solution of the congruence subgroup problem for SL n (n ≥ 3) and Sp 2 n (n ≥ 2) , Publ. Math. Inst. Hautes Études Sci. 33 (1967) 59–137] of Bass–Milnor–Serre. [ABSTRACT FROM AUTHOR]

Background: Intracranial pressure (ICP) can be continuously and reliably measured using invasive monitoring through an external ventricular catheter or an intraparenchymal probe. We explore electroencephalography (EEG) to identify a reliable real-time noninvasive ICP correlate. Methods: Using a previously described porcine model of intracranial hypertension, we examined the cross correlation between ICP time series and the slope of the EEG power spectral density as described by ϕ. We calculated ϕ as tan−1 (slope of power spectral density) and normalized it by π, where slope is that of the power-law fit (log frequency vs. log power) to the power spectral density of the EEG signal. Additionally, we explored the relationship between the ϕ time series and cerebral perfusion pressure. A total of 11 intracranial hypertension episodes across three different animals were studied. Results: The mean correlation between ϕ angle and ICP was − 0.85 (0.15); the mean correlation with cerebral perfusion pressure was 0.92 (0.02). Significant correlation occurred at zero lag. In the absence of intracranial hypertension, the absolute value of the ϕ angle was greater than 0.9 (mean 0.936 radians). However, during extreme intracranial hypertension causing cerebral circulatory arrest, the ϕ angle is on average below 0.9 radians (mean 0.855 radians). Conclusions: EEG ϕ angle is a promising real-time noninvasive measure of ICP/cerebral perfusion using surface electroencephalography. [ABSTRACT FROM AUTHOR]

Adequate prediction of postruminal outflows of essential AA (EAA) is the starting point of balancing rations for EAA in dairy cows. The objective of this meta-analysis was to compare the performance of 3 dairy feed evaluation systems (National Research Council [NRC], Cornell Net Protein and Carbohydrate System version 6.5.5 [CNCPS], and National Academies of Sciences, Engineering and Medicine [NASEM]) to predict EAA outflows (Trp was not tested). The data set included a total of 354 treatment means from 70 duodenal and 24 omasal studies. To avoid Type I error, mean and linear biases were considered of concern if statistically significant and representing >5.0% of the observed mean. Analyses were conducted on raw observed values and on observations adjusted for the random effect of study. The analysis on raw data indicates the ability of the feed evaluation system to predict absolute values whereas the analysis on adjusted values indicates its ability to predict responses of EAA outflows to dietary changes. For the prediction of absolute values (based on raw data), NRC underpredicted outflows of all EAA, from 5.3% to 8.6% of the observed mean (% obs.mean) except for Leu, Lys, and Val; NASEM overpredicted Lys (10.8% obs.mean); and CNCPS overpredicted Arg, His, Lys, Met, and Val (5.2 to 26.0% obs.mean). No EAA had a linear bias of concern with NASEM, followed by NRC for His (6.8% obs.mean), and CNCPS for all EAA (5.6 to 12.2% obs.mean) except Leu, Phe, and Thr. In contrast, for the prediction of responses to dietary changes (based on adjusted data), NRC had 2 EAA presenting a linear bias of concern, followed by NASEM and CNCPS with 4 and 6 EAA, respectively. Predictions of His showed a linear bias of concern (5.3 to 9.6% obs.mean) with the 3 feed evaluation systems. Measured chemistry of crude protein and EAA were reported for 1 or more feed ingredients of the ration in 36% of the studies, and resulted in decreased linear biases in the 3 feed evaluation systems. The difference in mean biases of Met outflows was systematically positive when comparing omasal versus duodenal studies. Predictions of Met outflows with NRC had a higher concordance correlation coefficient in duodenal (used to develop NRC equations) versus omasal studies, whereas the opposite was observed with CNCPS, the latter showing the lowest mean bias for Met in omasal sampling studies. The 30% difference in Met mean biases between sampling sites appeared related to a similar difference found for observed Met versus nonammonia nitrogen outflows between duodenal and omasal studies, which is independent of predictions. In conclusion, NRC and NASEM yielded accurate predictions of EAA outflows, with a small superiority of NASEM to predict absolute values, and slight superiority of NRC to predict the responses to dietary changes. In comparison, CNCPS may present mean and linear biases of concern for many EAA. Moreover, it remains to determine which sampling site is more representative of the true supply of EAA to the cows. [ABSTRACT FROM AUTHOR]

Background: Ionization chambers play an essential role in dosimetry measurements for kilovoltage (kV) x‐ray beams. Despite their widespread use, there is limited data on the absolute values for the polarity correction factors across a range of commonly employed ionization chambers. Purpose: This study aimed to investigate the polarity effects for five different ionization chambers in kV x‐ray beams. Methods: Two plane‐parallel chambers being the Advanced Markus and Roos and three cylindrical chambers; 3D PinPoint, Semiflex and Farmer chamber (PTW, Freiburg, Germany), were employed to measure the polarity correction factors. The kV x‐ray beams were produced from an Xstrahl 300 unit (Xstrahl Ltd., UK). All measurements were acquired at 2 cm depth in a PTW‐MP1 water tank for beams between 60 kVp (HVL 1.29 mm Al) and 300 kVp (HVL 3.08 mm Cu), and field sizes of 2–10 cm diameter for 30 cm focus‐source distance (FSD) and 4 × 4 cm2 – 20 × 20 cm2 for 50 cm FSD. The ionization chambers were connected to a PTW‐UNIDOS electrometer, and the polarity effect was determined using the AAPM TG‐61 code of practice methodology. Results: The study revealed significant polarity effects in ionization chambers, especially in those with smaller volumes. For the plane‐parallel chambers, the Advanced Markus chamber exhibited a maximum polarity effect of 2.5%, whereas the Roos chamber showed 0.3% at 150 KVp with the 10 cm circular diameter open‐ended applicator. Among the cylindrical chambers at the same beam energy and applicator, the Pinpoint chamber exhibited a 3% polarity effect, followed by Semiflex with 1.7%, and Farmer with 0.4%. However, as the beam energy increased to 300 kVp, the polarity effect significantly increased reaching 8.5% for the Advanced Markus chamber and 13.5% for the PinPoint chamber at a 20 × 20 cm2 field size. Notably, the magnitude of the polarity effect increased with both the field size and beam energy, and was significantly influenced by the size of the chamber's sensitive volume. Conclusions: The findings demonstrate that ionization chambers can exhibit substantial polarity effects in kV x‐ray beams, particularly for those chambers with smaller volumes. Therefore, it is important to account for polarity corrections when conducting relative dose measurements in kV x‐ray beams to enhance the dosimetry accuracy and improve patient dose calculations. [ABSTRACT FROM AUTHOR]

This paper concentrates on addressing fractional inequalities for exponential type convex functions. By means of exponential-type convexity, we firstly establish Hermite-Hadamard (HH) type inequalities for fractional integrals with exponential kernels. Secondly, based on the discovered fractional identity by separating [a; b] to n equal subintervals, and the fact that the twice derivative in absolute value is exponential type convex, we present multipoint-based HH inequalities, which cover the trapezoid- and Bullen-type inequalities for n = 1 and 2, correspondingly. During the period, some numerical examples with graphs are provided to show the validity of the deduced inequalities. [ABSTRACT FROM AUTHOR]

Dispersions of amino-functionalized silica in ethylene glycol (EG) and in aqueous glycol show excellent stability at room temperature. Stability at elevated temperatures would be much desired with respect to their potential application as heat-transfer fluids. Amino-functionalized silica was dispersed in EG and in 50–50 aqueous EG by mass. HCl and acetic acid were added to enhance the positive ζ potential. The dispersions were stored at 40, 60, 80, and 100 °C for up to 28 days, and ζ potential and apparent particle radius were studied as a function of elapsed time. The particles showed a positive ζ potential in excess of 40 mV (Smoluchowski), which remained unchanged for 28 days. Such a high absolute value of ζ potential is sufficient to stabilize the dispersion against flocculation and sedimentation. The apparent particle radius in acidified dispersions was about 70 nm, and it was stable for 28 days. The particles were larger in pH-neutral dispersions. The apparent particle radius was about 80 nm in fresh dispersions and it increased on long storage at 80 and 100 °C. [ABSTRACT FROM AUTHOR]

In this paper, we propose a modified spectral conjugate gradient (MSCG) method for solving absolute value equations associated with second-order cones (SOCAVEs). Some properties of the SOCAVEs are analyzed, and the global convergence of the MSCG method is discussed in depth. Numerical experiments are given to illustrate the effectiveness and competitiveness of our algorithm. [ABSTRACT FROM AUTHOR]

Purpose: This work presents a new two-step iterative technique for solving absolute value equations. The developed technique is valuable and effective for solving the absolute value equation. Various examples are given to demonstrate the accuracy and efficacy of the suggested technique. Design/methodology/approach: In this paper, we present a new two-step iterative technique for solving absolute value equations. This technique is very straightforward, and due to the simplicity of this approach, it can be used to solve large systems with great effectiveness. Moreover, under certain assumptions, we examine the convergence of the proposed method using various theorems. Numerical outcomes are conducted to present the feasibility of the proposed technique. Findings: This paper gives numerical experiments on how to solve a system of absolute value equations. Originality/value: Nowadays, two-step approaches are very popular for solving equations (1). For solving AVEs, Liu in Shams (2021), Ning and Zhou (2015) demonstrated two-step iterative approaches. Moosaei et al. (2015) introduced a novel approach that utilizes a generalized Newton's approach and Simpson's rule to solve AVEs. Zainali and Lotfi (2018) presented a two-step Newton technique for AVEs that converges linearly. Feng and Liu (2016) have proposed minimization approaches for AVEs and presented their convergence under specific circumstances. Khan et al. (2023), suggested a nonlinear CSCS-like technique and a Picard-CSCS approach. Based on the benefits and drawbacks of the previously mentioned methods, we will provide a two-step iterative approach to efficiently solve equation (1). The numerical results show that our proposed technique converges rapidly and provides a more accurate solution. [ABSTRACT FROM AUTHOR]

Inhomogeneous damping distribution leads to the occurrence of complex modes of structures. Complex modes' vibration and acoustic radiation characteristics are different from real modes. This paper studies the complex modal characteristics of inhomogeneously damped plates for forced vibration. We used the state space method to obtain the complex eigenvalues and eigenvectors of the vibration system and calculated the relationship between modal coordinates and frequency under unit force. The results show that the absolute values of the modal coordinates of two conjugate complex eigenvectors are different, and the structure's vibration is dominated by the eigenvectors corresponding to eigenvalues with positive imaginary parts near natural frequencies. When investigating the structural sound radiation in the vibration mode space, each mode's acoustic radiation is not independent but coupled with each other. The influence of the coupling between complex modes on the calculation results of the acoustic radiation power of the plate is studied in this paper. The results show that the coupling effect between modes cannot be ignored when calculating the acoustic radiation power based on complex modes. Finally, the error of calculating acoustic power using the decoupling approximation instead of the complex mode method is analyzed. [ABSTRACT FROM AUTHOR]

Here, identification of processes and systems in the sense of the least sum of absolute values is taken into consideration. The respective absolute value estimators are recognised as exceptionally insensitive to large measurement faults or other defects in the processed data, whereas the classical least squares procedure appears to be completely impractical for processing the data contaminated with such parasitic distortions. Since the absolute value quality index cannot be minimised analytically, an iterative solution is used to find optimal estimates of the parameters of the underlying regression model. In addition, an approximate recursive estimator is proposed and implemented for on‐line evaluation of system parameters. The convergence (basic property) of the iterative estimator is show to be proven and some aspects related to the absolute value criterion are explained. This allows for the formulation of practical conclusions and indication of directions for further research. In addition, the effectiveness of the described iterative‐recursive estimation procedures is practically verified by appropriate numerical experiments. [ABSTRACT FROM AUTHOR]

The objective of this study is to explore the patterns of alteration in left ventricular systolic function among patients with severe aortic stenosis (SAS) through the application of automatic myocardial motion quantification (aCMQ) techniques. Furthermore, we seek to ascertain dependable quantitative markers for the assessment of impaired left ventricular function in patients with SAS and an ejection fraction (EF) ≥ 60%. Seventy patients who underwent echocardiography and received a diagnosis of severe aortic stenosis (SAS) in the hospital from November 2021 to August 2022 were selected for the SAS group and categorized into three subgroups based on ejection fraction (EF)—SAS group with EF ≥ 60%, SAS group with EF ranging from 50% to 59%, and SAS group with EF < 50%. Concurrently, 30 healthy individuals were recruited at the hospital during the same timeframe to serve as the control group. Participants from both groups underwent standard transthoracic echocardiography to assess conventional echocardiographic parameters. Dynamic images were examined using automatic myocardial motion quantification (aCMQ) software to derive longitudinal peak strain (LPS) parameters, which were then subjected to statistical analysis. In comparison to the control group participants, the measurements of ascending aorta diameter (AoD), left atrium diameter (LAD), interventricular septal end diastolic thickness (IVSd), left ventricular posterior wall end diastolic thickness (LVPWd), peak systolic velocity (Vmax), and mean pressure gradient (MPG) were significantly higher in the SAS groups (p < 0.05). When compared to participants in the SAS group with an EF ≥ 60%, the values of IVSd, LVPWd, Vmax, and MPG in the SAS group with EF ranging from 50% to 59% were significantly elevated (p < 0.05). Similarly, left ventricular end-diastolic diameter (LVEDD), the ratio of early diastolic mitral inflow velocity to early diastolic mitral annular velocity (E/e'), and the ratio of early to late diastolic mitral inflow velocities (E/A) in the SAS group with EF < 50% were significantly elevated (p < 0.05). The absolute values of longitudinal peak strain (LPS) in the SAS groups were significantly lower in comparison to those in the control group (p < 0.05). Furthermore, all measurements of left ventricular global longitudinal systolic peak strain (GLPS) showed a positive correlation with MPG, a moderate negative correlation with aortic valve area index (AVAI), and a moderate positive correlation with E/A. Patients with SAS and an EF < 50% exhibited the most profound impairment in left ventricular myocardial function. Utilizing the aCMQ technique enables the precise and quantitative evaluation of the severity of impaired left ventricular systolic function in patients within the SAS group with an EF ≥ 60%. [ABSTRACT FROM AUTHOR]