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BACKGROUND: In pediatric ophthalmology, calculating intra-ocular lens (IOL) power can be challenging. It is important to predict if the post-surgery refractive error (RE) will meet the intended refractive goal. In this study, we aimed to investigate the factors and predictors influencing RE outcomes in children undergoing IOL implantation. METHODS: This was a retrospective cross-sectional cohort study that involved 47 eyes with congenital cataracts underwent IOL implantation. Each patient underwent follow-up visits at two months and two years' post-surgery. The IOL power calculations were conducted using the Holladay 1 formula, and both the prediction error (PE) and absolute prediction error (APE) were calculated. RESULTS: The mean age was 6.52 ± 4.61 years, with an age range of 1-15 years. The mean IOL power was 20.31 ± 6.57 D, and the mean post-operative refraction was 1.31 ± 2.65 D. The mean of PE and APE were 0.67 ± 1.77 and 1.55 ± 1.06 D, respectively. Whereas PE was correlated to axial length with an R-value of - 0.29 (P = 0.04). The calculation method had a significant negative relationship with APE and PE, with coefficients of - 1.05 (P = 0.009) and - 1.81 (P = 0.009), respectively. CONCLUSION: High astigmatism was associated with greater errors in the refractive outcome. The calculation methods had the most considerable impact on the post-operative RE. The customization of surgical approaches to accommodate individual characteristics is crucial. Further research with diverse subgroups is needed to comprehensively understand the influence of each factor.

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This study presents a 3D pick-rock contact calculation method for conical picks, aiming to develop a predictive method with high accuracy and lithological tolerance for peak cutting force (PCF). The method is based on the projection profile method and D. L. Sikarskie stress distribution function. By integrating Griffith's theory with rock damage constitutive model, the energy relationship between the rock fracturing process and crack propagation process is analyzed. Furthermore, in order to accurately correct the PCF, the energy correction function (C-Kf) is proposed to calculate the damage intensity index (Ke), which accounts for the relationship between rock brittleness and rock damage elastic-plastic energy. To validate the method, it is compared with full-scale cutting tests and three existing models, and statistical analysis confirms its high lithological tolerance and accuracy, the present model has the highest R2 of 0.90404, which is at least 12.5% higher relative to the mainstream models. Moreover, incorporating Ke into the method further enhances its predictive capability.

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At present, China's demand for high-speed railway construction is constantly increasing, and the construction of Multi line high-speed railway tunnels has been put on the agenda. The design and construction issues of super-large-sections tunnels urgently need to be addressed. The Xiabei mountain No. 1 and No. 2 tunnels in the Hangzhou-Taizhou Railway are typical shallow-buried super-large-section-tunnels in weak surrounding rock, and their design and construction issues are representative. Eleven monitoring sections were set up in the tunnel, including tunnel deformation, surrounding rock, shotcrete, steel frames, bolts and temporary support mechanical responses. Taking the monitoring data of the most typical cross-section as an example, the mechanical response of the support structure of a shallow-buried super-large-section tunnel was analyzed in detail. Based on previous research results, this paper discusses and summarizes the common construction problems of this type of tunnel, and puts forward corresponding suggestions. The existing formula for calculating surrounding rock pressure has poor applicability to super-large-section tunnels constructed by step excavation, resulting in conservative support parameters. Therefore, based on the monitoring values of surrounding rock pressure at 10 monitoring sections in Xiabei mountain No. 1 and No. 2 tunnels, empirical parameters reflecting the impact of step excavation were summarized. Based on the Wang formula and combined with the step excavation empirical parameters, an empirical formula for the surrounding rock pressure of shallow-buried super-large-section tunnels considering step excavation was constructed. The calculated results are in good agreement with the on-site monitoring data. This study can provide a good reference for similar projects.

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In order to explore the flexural behavior of a concrete sandwich panel under concentrated boundary conditions, based on Kirachhoff's elastic thin plate theory in this paper, the geometric deformation, physical conditions, and equilibrium relationship of a sandwich panel are deduced by constructing the layered analysis model of the sandwich panel, the basic differential equation of the flexural deformation of the concrete sandwich thin plate is obtained, and the mathematical expression of the internal force and displacement under the boundary condition of concentrated support is given. Combined with an engineering example, the proposed calculation method is verified. The results show that, in the arrangement of reliable connectors for concrete sandwich panels, the concrete wythes bear the load while the contribution of the core layer to the bending capacity of the structure can be ignored. When subjected to a laterally distributed load, the sandwich panel mainly experiences out-of-plane bending deformation, and the bending normal stress in the concrete panel layer shows a linear non-uniform distribution along the thickness direction of the panel. The bending deformation performance and bearing efficiency of a concrete sandwich slab with the change in concentrated support position have significant effects, and the load transfer efficiency can be improved by optimizing the arrangement of supports. Except for small local areas near the supports, the bending stress distribution and deformation behavior of the concrete sandwich panel can be accurately analyzed by the calculation method established in this paper.

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Introduction: Traditional methods for determining radiation dose in nuclear medicine include the Monte Carlo method, the discrete ordinate method, and the point kernel integration method. This study presents a new mathematical model for predicting the radiation dose rate in the vicinity of nuclear medicine patients. Methods: A new algorithm was created by combining the physical model of "cylinder superposition" of the human body with integral analysis to assess the radiation dose rate in the vicinity of nuclear medicine patients. Results: The model accurately predicted radiation dose rates within distances of 0.1-3.0 m, with a deviation of less than 11% compared to observed rates. The model demonstrated greater accuracy at shorter distances from the radiation source, with a deviation of only 1.55% from observed values at 0.1 m. Discussion: The model proposed in this study effectively represents the spatial and temporal distribution of the radiation field around nuclear medicine patients and demonstrates good agreement with actual measurements. This model has the potential to serve as a radiation dose rate alert system in hospital environments.

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Ignition electrodes have an immense impact on the accurate measurement of the flame propagation spherical radius. In this study, a flame-radius calculation method is designed. The method is able to eliminate effects due to the ignition electrodes. The adaptability and optimization effects of the proposed method are analyzed. The results show that the ratio of the angle is affected by the ignition electrodes under the Han II method. There are three obvious divisions include a high-value area, a sharp-variation area, and a mild-variation area. The ratio of the angle affected by the ignition electrodes is only applicable to the mild-variation region when the flame presents respective convex and concave distributions. For these distributions, the increment rate of the mean radius is 0.4-0.85% and 0.42-3.19%. The reduced rate of the standard deviation of the radius extraction value is 11.91-22.1% and 5.13-17.99%, and the reduced rate of the radius extraction value range is 20.32-39.51% and 0.32-8.09%.

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The seismic deterioration effects of anchor cables and slope structural planes are often neglected in the dynamic stability analysis of anchored rocky slopes to the extent that the stability of slopes is overestimated. In this paper, a dynamic calculation method for anchored rocky slopes considering the seismic deterioration effect is established, and a stability evaluation method for anchored rocky slopes based on the Gaussian mixture model is proposed. The seismic deterioration effect on the stability of anchored rocky slopes is quantitatively analyzed with an engineering example, and the relationship between seismic intensity and the failure probability of slopes is clarified. The results show that compared with the calculation method without considering the seismic deterioration effect, the minimum safety factor and post-earthquake safety factor obtained by the proposed method in this paper are smaller. The number of seismic deteriorations of the slope is used as the number of components of the Gaussian mixture model to construct the failure probability model of the slope, which can accurately predict the failure probability of anchored rocky slopes. The research results significantly improve the accuracy of the stability calculation of anchored rocky slopes, which can be used to guide the seismic design and safety assessment of anchored rocky slopes.

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The most effective method for determining the coordinates of the railway track axis is based on using mobile satellite measurements. However, there are situations in which the satellite signal may be disturbed (due to field obstructions) or completely disappear (e.g., in tunnels). In these situations, the ability to measure the value of the directional angle of a moving rail vehicle using an inertial system is useful. The directional angle is determined on a topographic map as the angle between the direction of the vehicle's longitudinal axis (or the direction of a tangent to the track axis) and the reference direction, which is the north. This article presents a method for determining the directional angle of a railway line based on appropriate measurement data. The latter should be Cartesian coordinates of the track axis, allowing for the visualization of a given railway route and permitting a general orientation of its course to be obtained. The presented proposal for solving the problem refers to the assumptions made in the method for determining the curvature of the railway track axis using the moving chord. The assumptions of the proposed method for determining the directional angle of the railway route are discussed, along with the appropriate computational algorithms. The accuracy of this method is assessed using the adopted model geometric layout. Reference is also made to the appropriate method for determining the curvature of the railway track axis. In conclusion, we provide an example of determining the directional angle based on measurement data.

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Simulating the mechanical behavior of cellular materials stands as a pivotal step in their practical application. Nonetheless, the substantial multitude of unit cells within these materials necessitates a considerable finite element mesh, thereby leading to elevated computational expenses and requisites for formidable computer configurations. In order to surmount this predicament, a novel and straightforward equivalent calculation method is proposed for the computation of mechanical properties concerning both random and ordered hyper-elastic cellular materials. By amalgamating the classical finite element approach with the distribution attributes of cells, the proposed equivalent calculation method adeptly captures the deformation modes and force-displacement responses exhibited by cell materials under tensile and shear loads, as predicted through direct numerical simulation. This approach reflects the deformation characteristics induced by micro-unit cells, elucidates an equivalent principle bridging cellular materials and equivalent materials, and substantially curtails exhaustive computational burdens. Ultimately, this method furnishes an equivalent computational strategy tailored for the engineering applications of cellular materials.

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With the remarkable development of deep learning in the field of science, deep neural networks provide a new way to solve the Stefan problem. In this paper, deep neural networks combined with small sample learning and a general deep learning framework are proposed to solve the two-dimensional Stefan problem. In the case of adding less sample data, the model can be modified and the prediction accuracy can be improved. In addition, by solving the forward and inverse problems of the two-dimensional single-phase Stefan problem, it is verified that the improved method can accurately predict the solutions of the partial differential equations of the moving boundary and the dynamic interface.

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Using various versions of quantum-chemical calculation, namely four versions of density functional theory (DFT), (DFT B3PW91/TZVP, DFT M06/TZVP, DFT B3PW91/Def2TZVP, and DFT M06/Def2TZVP) and two versions of the MP method (MP2/TZVP and MP3/TZVP), the existence possibility of the carbon-nitrogen-containing compound having an unusual M: nitrogen ratio of 1:20, unknown for these elements at present, was shown. Structural parameters data are presented; it was noted that, as may be expected, CN4 grouping has practically a tetrahedral structure, and the chemical bond lengths formed by nitrogen atoms and a carbon atom in the frameworks of each of the calculation methods indicated above are equal to each other. Thermodynamical parameters, NBO analysis data, and HOMO/LUMO images for this compound are also presented. A good agreement between the calculated data obtained using the above three quantum-chemical methods was noticed, too.

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Microorganisms have been linked to a variety of critical human disease, thanks to advances in sequencing technology and microbiology. The growing recognition of human microbe-disease relationships provides crucial insights into the underlying disease process from the perspective of pathogens, which is extremely useful for pathogenesis research, early diagnosis, and precision medicine and therapy. Microbe-based analysis in terms of diseases and related drug discovery can predict new connections/mechanisms and provide new concepts. These phenomena have been studied via various in-silico computational approaches. This review aims to elaborate on the computational works conducted on the microbe-disease and microbe-drug topics, discuss the computational model approaches used for predicting associations and provide comprehensive information on the related databases. Finally, we discussed potential prospects and obstacles in this field of study, while also outlining some recommendations for further enhancing predictive capabilities.

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Taking cities in Zhejiang Province of China from 2011 to 2020 as the research object, a multi-dimensional urbanization quality evaluation index system was constructed using the comprehensive analysis method, and the urbanization quality of 11 cities in Zhejiang Province was quantitatively measured using the entropy weight method. The system classification and time-space evolution analysis were carried out using ArcGIS software (Environmental Systems Research Institute, Inc., RedLands, CA, USA) to comprehensively study the evolution characteristics and influencing factors of the urbanization quality of cities in Zhejiang Province. This study provides a reference for local governments to formulate feasible urbanization development strategies and policies to promote the high-quality development of urbanization and for the construction of new urbanization in other provinces and cities.

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A new type of structural material has begun to be used in the reinforcement of deformed shield tunnels, known as filament wound profiles (FWPs). The FWPs are formed by wrapping carbon-fiber-reinforced polymer (CFRP) around steel tubes that are grouted with concrete inside. However, for practical engineering applications, the design of FWPs requires further insight into their mechanical behavior, since there is no standard method for this at present. In this study, compression and bending tests were carried out to investigate the mechanical behavior of FWPs. A reliable numerical model was established based on the test results, and the effects of the design parameters on the mechanical properties of the FWPs were analyzed qualitatively. The key design parameters of bearing capacity and stiffness were determined through numerical experiments. Based on the experimental results, a method for the calculation of bearing capacities and stiffness was proposed. It was verified that the results of the calculation formulae and the experimental results showed good agreement. Moreover, the results of the formulae were relatively conservative, and most of the errors were within 15%. Thus, this calculation method can be used to calculate the load-bearing capacity and stiffness of FWPs in practical projects.

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Achieving carbon neutrality is an urgent, complex and arduous task in China. How to effectively exert carbon sequestration and improve carbon sequestration capacity of urban ecosystems should be solved. Compared with other terrestrial ecosystem types, frequent anthropogenic activities lead to more abundant carbon sink elements of urban ecosystems and more complex factors affecting their carbon sequestration capacity. Based on researches at multiple spatial and temporal scales, we analyzed key factors affecting the carbon sequestration capacity of urban ecosystems from different perspectives. We illuminated the composition and characteristics of carbon sinks of urban ecosystems, summarized the methods and characteristics of carbon sequestration capacity of urban ecosystems, and revealed the impact factors of carbon sequestration capacity of different carbon sink elements and the comprehensive impact factors of carbon sinks of urban ecosystems under the influence of human activities. With the continuous improved understanding of carbon sinks of urban ecosystems, it is necessary to further improve the accounting method of carbon sequestration capacity of artificial carbon sink systems, explore the key impact factors of comprehensive carbon sequestration capacity, change the research method from global to spatially weighted, discover the spatial coupling relationship between artificial and natural carbon sink systems, find out the optimal artificial-natural spatial configuration to achieve carbon sequestration capacity enhancement, break the limitations of increasing carbon sink of urban ecosystems, and finally contribute to the achievement of the urban carbon neutrality goal.

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In order to solve the problem of excessive short-circuit current in the present power system, a fault current limiter has become a new type of power device with high demand and is one of the current research hotspots. The flux-coupling type superconducting fault current limiter (FC-SFCL) generates a current-limiting impedance through decoupling superconducting parallel inductance based on the circuit breakers' fractional interruption. The principle is simple, and the impedance is low during normal operation. It can directly use the existing circuit breaker to open a short circuit that is much higher than its own breaking capacity. Thus, it can be used for large-capacity fault current limiting and effective failure breaking. This paper focused on exploring and studying the implementation scheme of practical products of FC-SFCL. Considering that the quenched-type parallel inductance can limit the first peak value of the fault current, a quenched-type improvement scheme was proposed. Then, an electromagnetic design method based on the simplified calculation of the number of parallel tapes was proposed, which simplified the design process and reduced the design difficulty of the quenched FC-SFCL. Taking a 10 kV/500 A/5 kA quenched prototype as an example, its electromagnetic design was completed, and the performances of the non-quenched and quenched schemes were compared. The results showed that, compared to the non-quenched structure, the technical economics of the quenched one were more prominent, and it can be used preferentially for engineering prototypes. This study about the scheme of the quenched FC-SFCL and its electromagnetic design method is useful for promoting the implementation of the current limiter engineering prototype.

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BACKGROUND: Dose evaluation at longitudinal positions of body computed tomography (CT) scans is useful for CT quality assurance programs and patient organ dose evaluation. Accurate estimates depend on both patient size and scan length. PURPOSE: To propose practical evaluation of the average dose to the transverse slab of an axial image slice for adult body CT examinations, considering not only patient size but also scan length, and to compare the results with those of Monte Carlo (Geant4) simulation [Dsim (z)] and size-specific dose estimates at longitudinal positions of scans [SSDE(z)] from international standards (IEC publication no. 62985). METHODS: In a scan series, the total dose at each z-axis location was calculated using the input information identical to the SSDE(z) evaluation. Each axial image slice (slice thickness, 2.5 or 5 mm) was first considered independently. Its z-axis coverage and CTDIvol (from the DICOM headers) were used to directly calculate a z-axis dose profile for the average dose over the cross-section of a water phantom, using the approach to equilibrium function. The phantom diameter was taken to be equal to the patient water equivalent diameter at that slice. The above was repeated at all slices and the dose at each z-axis location was accumulated from all profiles, referred to as Dcalc (z). For validation, we considered a cohort of 65 patients, who underwent chest and abdominopelvic examinations. The resultant Dcalc (z) was compared with Dsim (z) and SSDE(z), both available in a previous paper. RESULTS: Dcalc (z) evaluation could be used to accurately assess the scan range average dose, with an accuracy of 7.1%-8.7% for 65 patients in two examinations. On individual image slices, the maximum difference in magnitude between Dcalc (z) and Dsim (z) [and between SSDE(z) and Dsim (z) in parentheses] was 37.5% (85%) [two edges (2 × 5 cm) of chest scan range], 17.8% (35.2%) (the remaining central region of chest scan), 26.8% (74.1%) [two edges (2 × 5 cm) of abdominopelvic scan range], and 14.2% (22.5%) (the remaining central region of abdominopelvic scan). CONCLUSIONS: Identical input data are used for Dcalc (z) and SSDE(z) evaluations. The latter is limited to the z-axis locations within scan range. At each image slice, SSDE(z) is equivalent to the midpoint dose of a fixed-mA scan of 15-30 cm (scan length). In contrast, Dcalc (z) considers dose accumulation from varying scan length (from sub-centimeter to about 1 m) and tube current, and dose profile is also computed outside scan range. Besides greatly improving dose evaluation for individual image slices, Dcalc (z) allows for evaluating dose accumulation from multiple series, which typically span different scan ranges. Our proposal may assist CT manufacturers and dose index monitoring software in assessing dose at longitudinal positions of body CT scans.

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BACKGROUND: To evaluate the accuracy of different preoperative calculation methods of osteotomy size in ankylosing spondylitis with thoracolumbar or lumbar kyphosis and analyze its clinical significance. METHODS: Twenty-two cases of AS patients with thoracolumbar or lumbar kyphosis, from January 2015 to December 2018, who underwent one-level SPO surgery in our hospital, were retrospectively reviewed. The sagittal parameters were measured at pre-operation and last follow up using Surgimap software, and theoretical values of sagittal parameters were calculated according to pre-operative PI. The osteotomy angles of different methods were measured using Surgimap software. Paired t test was used to for the statistical analysis. RESULTS: The mean follow-up time of all patients was 30.00 [Formula: see text] 3.56 months. The osteotomy sites were located at T12 in 3 cases, L1 in 6 cases, L2 in 9 cases, and L3 in 4 cases. Compared to pre-operative sagittal parameters, post-operative PT, SS, LL, and SVA were significantly improved (P [Formula: see text] 0.05). Compared to the OVA (46.57 [Formula: see text] 2.32 [Formula: see text]), there was a significantly larger angle predicted by Surgimap method (53.80 [Formula: see text] 9.79 [Formula: see text]), CAM-HA method (56.61 [Formula: see text] 8.58 [Formula: see text]), and HP-HA method (60.07 [Formula: see text] 13.58 [Formula: see text]), respectively (P [Formula: see text] 0.05). But no significant difference was found between the postoperative osteotomy angle and those of SFA method (51.24 [Formula: see text] 12.14 [Formula: see text]) and FBI method (48.08 [Formula: see text] 12.49 [Formula: see text]) (P [Formula: see text] 0.05). CONCLUSION: For AS patients with thoracolumbar or lumbar kyphosis, the SFA method, FBI method, and Surgimap method can be used to predict the osteotomy angle precisely, however, considering the rationality of parameter settings and the operability, SFA method is relatively more suitable for such population.

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It is very necessary to study the mechanism of rock burst, which is related to the safe construction of many geotechnical projects. Previous studies have shown that small trigger stress will lead to large energy release, but the specific conditions that cause the release and how to quantify the energy are urgent problems to be solved. In this study, an innovative calculation method of rock mass energy release is proposed, and the calculated release energy is consistent with the monitoring results of field monitoring equipment. The revealed mechanism of rock burst reflected is that under the condition of a large-ratio pre-state stress field (mostly > 2.5), a small trigger stress field will lead to a large amount of energy release under "late butterfly shape" or "final butterfly shape" of the plastic zone. This study reveals the key factor of rock burst, which plays an important reference role for the mechanism research, subsequent monitoring and treatment method of rock burst.

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The physician burnout, poor ergonomics are hardly conducive to the sustainability and high quality of colonoscopy. In order to reduce doctors' workload and improve patients' experiences during colonoscopy, this paper proposes a multistage adaptive control approach based on image contour data to guide the autonomous navigation of endoscopes. First, a fast image preprocessing and contour extraction algorithms are designed. Second, different processing algorithms are developed according to the different contour information that can be clearly extracted to compute the endoscope control parameters. Third, when a clear contour cannot be extracted, a triple control method inspired by the turning of a novice car driver is devised to help the endoscope capture clear contours. The proposed multistage adaptive control approach is tested in an intestinal model over a variety of curved configurations and verified on the actual colonoscopy image. The results reveal the success of the strategy in both straight sections of this intestinal model and in tightly curved sections as small as 6 cm in radius of curvature. In the experiment, processing time for a single image is 20-25 ms and the accuracy of judging steering based on intestinal model pictures is 96.7%. Additionally, the average velocity reaches 3.04 cm/s in straight sections and 2.49 cm/s in curved sections respectively.

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