Search

In order to study the best expression of the acceleration power of the earthquake ground motion model, an improved Hu Yuxian - European Virtual Earthquake Ground Motion Model was proposed on the basis of analysis of Kimi Kiyo model, Hu Yuxian model and Ou Jinping model. The mathematical derivation of the equations of motion was carried out by using Laplasse transformation and obtained the acceleration spectrum of the seismic ground motion of the Ou Jinping Hu Yuxian model. Research results show that the displacement, velocity and acceleration power spectrum of the Ou Jinping Hu Yuxian model are not singular points at zero frequency; the corresponding displacement, velocity, and acceleration variance which in maximum degree satisfy the real situation of the earthquake ground motion can be obtained from the finite value. [ABSTRACT FROM AUTHOR] more...

The strain‐driven morphotropic boundary in BiFeO3 can enhance the piezoelectric properties. However, the tetragonal phase has generally been observed in BiFeO3 films grown on substrates with intense compressive strain (more than −4.5%) within a limited thickness range (<300 nm) due to significant thickness‐dependent strain relaxation during film growth at high deposition temperatures. This work proposes suppressing thickness‐dependent strain relaxation by decreasing growth temperature. Utilizing a hydrothermal method, the growth temperature of epitaxial BiFeO3 films decreases to 200 °C. As a result, the tetragonal phase is observed in 600‐nm‐thick BiFeO3 film on (001) SrTiO3 substrates (strain equals only −1.5%), accompanied by the monoclinic phase. This SrTiO3‐available morphotropic phase boundary significantly enhances the piezoelectric response (d33,f′=110pmV−1)$ {({d}^{\prime}_{\rm 33,f} = 110\, {\rm pm\, V}^{-1})} $ in epitaxial BiFeO3 film. Ex situ and in situ measurements, theoretical calculations, and simulation confirm that the SrTiO3‐available morphotropic phase boundary originates from the suppressed strain relaxation. Furthermore, a critical temperature (400 °C), below which the tetragonal phase can be maintained, is identified to offer an applicable strategy for extending strain‐driven morphotropic phase boundary for high‐performance piezoelectric films. [ABSTRACT FROM AUTHOR] more...

Epitaxial (Bi, K)TiO3 films with 800- to 900-nm thicknesses were grown hydrothermally at 200 °C on SrTiO3 substrates covered with SrRuO3 layers. Perfectly (001)-oriented films grew on (100)SrTiO3 due to good lattice matching. Films on (110)SrTiO3 had mixed orientations of dominant (110) and minor (101), while three types of (111) orientations with in-plane 120° rotation were observed for the film on (111)SrTiO3. The (101) and (110) orientations of the film deposited on (110)SrTiO3 were tilted by approximately 2.6° and 1.6°, respectively, from surface normal due to the formation of a 90° domain with a twinning plane. The plane-view measurement for the film deposited on (111)SrTiO3 showed nine spots. These are explained by the presence of 15 possible spots resulting from the relaxed 90° domain combination and by overlapping. The lattice parameters of these films explain the tilting angles of these domains. These results reveal the formation of perfectly relaxed 90° domain structures for films grown on (110) and (111)SrTiO3. This differs from our previous data for tetragonal Pb(Zr,Ti)O3 films grown above TC on (110) and (111)SrTiO3 because the present films directly grow the ferroelectric films below TC without phase change. The tilting angle of the polar-axis and the volume fraction of the 90° domain can explain the piezoelectric responses of these films assuming that films have purely an up-state. This suggests that these films show almost pure up-state polarization without 180° domains, at least along surface-normal directions. These data show that these films have domain structures different from the well-known ones for the tetragonal Pb(Zr,Ti)O3 films. [ABSTRACT FROM AUTHOR] more...

To study the influence of random seismic responses on the structure of a large-span double-deck steel truss cable-stayed bridges under the effects of high-intensity rare earthquakes, a new power spectral model was proposed based on improvements to existing power spectra for fitting the improved power spectra of random seismic responses. The bridge finite element model established using ANSYS was employed as an engineering example for computational analysis to investigate whether the improved spectrum exhibited better adaptability and feasibility under high-intensity rare earthquake compared with other power spectra. The results indicated that the power spectral model, based on improvements to the original power spectra, had a more pronounced filtering effect on the low-frequency and high-frequency portions. Moreover, under the consistent three-dimensional excitation, the vertical displacement of the main beam was the greatest, indicating that the improved spectrum had better adaptability than other power spectra in studying the high-intensity rare earthquakes affecting bridges. It also reflected the feasibility of using the improved spectrum for studying the random responses to high-intensity rare earthquakes, providing a reference for bridge design concerning rare earthquakes in large-span bridges. [ABSTRACT FROM AUTHOR] more...

Copyright of Irrigation & Drainage is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...

The oriented lamellar K-rich exsolutions within clinopyroxene host were recognized in garnet peridotite massif at Zhimafang in the Sulu ultrahigh pressure metamorphic terrane, eastern China. EMP and TEM analyses revealed that the composition and the index of electron diffraction for this exsolution are corresponding with phlogopite, and the shape is the lamellae with 1 µm in width and 5 to 30 µm in length. Moreover, the topotaxy is that the (001) of K-rich exsolution parallels to (100) of the clinopyroxene host. The electron diffraction analyzing shows the exsolution is of a 1M polymorphism. The high-resolution lattice fringe image displays the stack features along [001], which only a layer mineral shows. We conclude that the clinopyroxene with 1M and K-rich exsolution was probably derived from mantle depths over 240 km, thus resulting from decompressional exsolution in the initial stage of slab exhumation. [ABSTRACT FROM AUTHOR] more...

The design of drill pipe joint thread with unequal taper is proposed to investigate the fracture failure of the API NC38 used in the drill pipe joint of the SU36-8-4H2 well. The effect of changes in thread taper on the stress distribution and mechanical properties of drill pipe joints is analyzed and compared with the API standard thread to determine the optimal thread structure with unequal taper. The results reveal highly concentrated stress at the last engaged thread root of API NC38 single-shoulder thread (SUT) may cause early yield failure of the joint threads. Adjusting the unequal taper of the pin thread mitigates uneven stress distribution in NC38 single and double-shoulder threads and enhances connection strength, particularly for SUT-II and DUT-I. However, altering the box thread's unequal taper modifies the stress concentration slightly in NC38 single and double-shoulder threads. This offers limited tensile and compressive strength improvement. The maximum Mises stress value of SUT-II is reduced by 56.69% compared to SUT. The maximum Mises stress value of DUT-I is reduced by 34.87% compared to NC38 double-shoulder joint thread (DUT). This design approach can guide the optimization of other API threads and enhance joint strength for non-API and specialized taper threads. [ABSTRACT FROM AUTHOR] more...

Introduction: Adverse drug events (ADEs) pose a significant challenge in current clinical practice. Machine learning (ML) has been increasingly used to predict specific ADEs using electronic health record (EHR) data. This systematic review provides a comprehensive overview of the application of ML in predicting specific ADEs based on EHR data. Methods: A systematic search of PubMed, Web of Science, Embase, and IEEE Xplore was conducted to identify relevant articles published from the inception to 20 May 2024. Studies that developed ML models for predicting specific ADEs or ADEs associated with particular drugs were included using EHR data. Results: A total of 59 studies met the inclusion criteria, covering 15 drugs and 15 ADEs. In total, 38 machine learning algorithms were reported, with random forest (RF) being the most frequently used, followed by support vector machine (SVM), eXtreme gradient boosting (XGBoost), decision tree (DT), and light gradient boosting machine (LightGBM). The performance of the ML models was generally strong, with an average area under the curve (AUC) of 76.68% ± 10.73, accuracy of 76.00% ± 11.26, precision of 60.13% ± 24.81, sensitivity of 62.35% ± 20.19, specificity of 75.13% ± 16.60, and an F1 score of 52.60% ± 21.10. The combined sensitivity, specificity, diagnostic odds ratio (DOR), and AUC from the summary receiver operating characteristic (SROC) curve using a random effects model were 0.65 (95% CI: 0.65–0.66), 0.89 (95% CI: 0.89–0.90), 12.11 (95% CI: 8.17–17.95), and 0.8069, respectively. The risk factors associated with different drugs and ADEs varied. Discussion: Future research should focus on improving standardization, conducting multicenter studies that incorporate diverse data types, and evaluating the impact of artificial intelligence predictive models in real-world clinical settings. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display%5frecord.php?ID=CRD42024565842, identifier CRD42024565842. [ABSTRACT FROM AUTHOR] more...

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...

Copyright of Journal of Natural Disasters is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) more...