Deep structure of the Southeast Asian curved subduction system and its dynamic process

The deep structure,material circulation,and dynamic processes in the Southeast Asia have long been an elusive scientific puzzle due to the lack of systematic scientific observations and recognized theoretical models.Based on the deep seismic tomography using long-period natural earthquake data,in this study,the deep structure and material circulation of the curved subduction system in Southeast Asia was studied,and the dynamic processes since 100 million years ago was reconstructed.It is pointed out that challenges still exist in the precise reconstruction of deep mantle structures of the study area,the influence of multi-stage subduction on deep material exchange and shallow magma activity,as well as the spatiotemporal evolution and coupling mechanism of multi-plate convergence.Future work should focus on high-resolution land-sea joint 3-D seismic tomography imaging of the curved subduction system in the Southeast Asia,combined with geochemical analysis and geodynamic modelling works.

Effect of boundary slip on electroosmotic flow in a curved rectangular microchannel

The aim of this study is to numerically investigate the impact of boundary slip on electroosmotic flow(EOF) in curved rectangular microchannels. Navier slip boundary conditions were employed at the curved microchannel walls. The electric potential distribution was governed by the Poisson–Boltzmann equation, whereas the velocity distribution was determined by the Navier–Stokes equation. The finite-difference method was employed to solve these two equations. The detailed discussion focuses on the impact of the curvature ratio, electrokinetic width, aspect ratio and slip length on the velocity. The results indicate that the present problem is strongly dependent on these parameters. The results demonstrate that by varying the dimensionless slip length from 0.001 to 0.01 while maintaining a curvature ratio of 0.5 there is a twofold increase in the maximum velocity. Moreover, this increase becomes more pronounced at higher curvature ratios. In addition, the velocity difference between the inner and outer radial regions increases with increasing slip length. Therefore, the incorporation of the slip boundary condition results in an augmented velocity and a more non-uniform velocity distribution. The findings presented here offer valuable insights into the design and optimization of EOF performance in curved hydrophobic microchannels featuring rectangular cross-sections.

Resilient performance of self-centering hybrid rocking walls with curved interface under pseudo-static loading

Frame and rocking wall(FRW)structures have excellent resilient performance during earthquakes.However,the concrete at interfacial corners of rocking walls(RWs)is easily crushed due to local extreme compression during the rocking process.An innovative RW with a curved interface is proposed to prevent interfacial corners from producing local damage,enhancing its earthquake resilient performance(ERP).The precast wall panel with a curved interface is assembled into an integral self-centering hybrid rocking wall(SCRW)by two post-tensioned unbonded prestressed tendons.Moreover,two ordinary energy dissipation steel rebars and two shear reinforcements are arranged to increase the energy dissipation capacity and lateral resistance.Two SCRW specimens and one monolithic reinforced concrete(RC)shear wall(SW)were tested under pseudo-static loading to compare the ERPs of the proposed SCRW and the SW,focusing on studying the effect of the curved interface on the SCRW.The key resilient performance of rocking effects,failure modes,and hysteretic properties of the SCRW were explored.The results show that nonlinear deformations of the SCRW are concentrated along the interface between the SCRW and the foundation,avoiding damage within the SCRW.The restoring force provided by the prestressed tendons can effectively realize self-centering capacity with small residual deformation,and the resilient performance of the SCRW is better than that of monolithic SW.In addition,the curved interface of the SCRW makes the rocking center change and move inward,partially relieving the stress concentration and crush of concrete.The rocking range of the rocking center is about 41.4%of the width of the SCRW.

受试者工作特征曲线(ROC曲线)的应用分析

目的:通过分析《中国计划生育学杂志》中受试者工作特征曲线(简称ROC曲线)的应用情况,为规范应用ROC曲线提供建议。方法:在中国知网检索2018年1月1日-2022年12月31日《中国计划生育学杂志》发表的与ROC曲线相关的文献,根据是否使用多指标联合预测结局,将文献分为单独组和联合组,分析文献的发表数量变化趋势、研究领域、应用条件、统计软件和模型。结果:共获得323篇文献。根据纳入排除标准,排除11篇文献,最终纳入312篇,其中单独组125篇、联合组187篇。最常用的统计软件为SPSS,数量达303篇,占97.1%,286篇文章仅提及使用ROC分析诊断价值,而未指出具体的拟合方法。2018-2022年的文章发表数量呈逐年上升的趋势,所纳入学科领域文献数量的排名前3位的依次是围产医学(187篇,59.9%)、妇科肿瘤学(45篇,14.4%)和普通妇科学(40篇,12.8%)。纳入文献样本量M(P25,P75)为180.5(127,242),其中样本量<100例的文章29篇,占9.3%。整体的AUC值M(P25,P75)为0.812(0.747,0.881),68.3%的AUC值位于0.7~0.9,<0.5的AUC值共7个,占0.6%。在≥2个指标的诊断试验研究中,149篇文章中未进行AUC值统计学差异性检验,仅报告指标间诊断价值的高低;29篇文章仅报告统计学比较的P值,未报告具体使用的统计学比较方法。结论:在ROC曲线的应用中,需选择合适的模型,并建议在文章的方法部分详细报告所用的ROC模型和统计软件,若存在多个指标的比较,需进行统计学检验,并报告相应的Z值和P值。

糖尿病足复发风险预测模型的构建:联合时间依赖ROC的生存分析

目的:采用回顾性队列研究的方法,以时间依赖ROC曲线联合生存分析预测糖尿病足(Diabetic foot ulceration,DFU)复发的危险因素并构建预测模型。方法:收集2018年1月-2023年1月于笔者科室住院治疗的DFU患者临床资料并随访患者的复发情况,设计研究因素为年龄、性别、是否合并高血压、血谷丙转氨酶值(Alanine aminotransferase,ALT)、血谷草转氨酶值(Aspartate aminotransferase,AST)、血碱性磷酸酶值(Alkaline phosphatase,ALP)、血谷酰转肽酶值(Gamma-glutamyltransferase,GGT)、血乳酸脱氢酶值(Lactate dehydrogenase,LDH)、白蛋白、血糖控制情况、血尿素氮值、血肌酐值、下肢血管病变、Wagner分级、是否存在骨质破坏、有无介入手术、有无截肢(趾)、有无植皮、是否吸烟共19项。连续数据以时间依赖受试者工作特征曲线(time-ROC)计算最佳截断值转化为分类数据,以K-M法计算复发率,log-rank检验进行单因素分析,COX比例风险回归模型进行多因素分析并构建预测模型,C-index评价模型准确度。结果:共纳入74例DFU患者。糖尿病足愈合后的1、2、3、4年复发率分别为:12.1%、24.8%、33.8%、43.3%。是否吸烟(P=0.002)、Wagner分级(P=0.004)、是否存在骨质破坏(P=0.038)、是否合并下肢血管病变(P<0.001)、年龄大小(P=0.034)、肌酐值高低(P=0.045)、有无截肢(P=0.022)是DFU复发的危险因素,其中吸烟(P<0.001,HR=19.805)、年龄≥73岁(P=0.009,HR=9.429)、血肌酐值≥66μmol/L(P=0.024,HR=5.423)是DFU复发的独立危险因素。糖尿病足复发的预测模型:Y=2.986X1+2.244X2+1.691X3(吸烟=X1,年龄水平=X2,肌酐水平=X3),C-index=0.888,模型准确性高。结论:基于时间依赖ROC联合生存分析构建的预测模型对判断糖尿病足复发率的准确度高。

Inverse design of mechanical metamaterial achieving a prescribedconstitutive curve

Besides exhibiting excellent capabilities such as energy absorption,phase-transforming metamaterials offer a vast design space for achieving nonlinear constitutive relations.This is facilitated by switching between different patterns under deformation.However,the related inverse design problem is quite challenging,due to the lack of appropriate mathematical formulation and the convergence issue in the post-buckling analysis of intermediate designs.In this work,periodic unit cells are explicitly described by the moving morphable voids method and effectively analyzed by eliminating the degrees of freedom in void regions.Furthermore,by exploring the Pareto frontiers between error and cost,an inverse design formulation is proposed for unit cells.This formulation aims to achieve a prescribed constitutive curve and is validated through numerical examples and experimental results.The design approach presented here can be extended to the inverse design of other types of mechanical metamaterials with prescribed nonlinear effective properties.

A comparative study of data-driven battery capacity estimation based on partial charging curves

With its generality and practicality, the combination of partial charging curves and machine learning(ML) for battery capacity estimation has attracted widespread attention. However, a clear classification,fair comparison, and performance rationalization of these methods are lacking, due to the scattered existing studies. To address these issues, we develop 20 capacity estimation methods from three perspectives:charging sequence construction, input forms, and ML models. 22,582 charging curves are generated from 44 cells with different battery chemistry and operating conditions to validate the performance. Through comprehensive and unbiased comparison, the long short-term memory(LSTM) based neural network exhibits the best accuracy and robustness. Across all 6503 tested samples, the mean absolute percentage error(MAPE) for capacity estimation using LSTM is 0.61%, with a maximum error of only 3.94%. Even with the addition of 3 m V voltage noise or the extension of sampling intervals to 60 s, the average MAPE remains below 2%. Furthermore, the charging sequences are provided with physical explanations related to battery degradation to enhance confidence in their application. Recommendations for using other competitive methods are also presented. This work provides valuable insights and guidance for estimating battery capacity based on partial charging curves.

Comparison of electrochemical behaviors of Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe and Ti-6Al-4V titanium alloys in NaNO_(3) solution

The Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe(β-CEZ)alloy is considered as a potential structural material in the aviation industry due to its outstanding strength and corrosion resistance.Electrochemical machining(ECM)is an efficient and low-cost technology for manufacturing theβ-CEZ alloy.In ECM,the machining parameter selection and tool design are based on the electrochemical dissolution behavior of the materials.In this study,the electrochemical dissolution behaviors of theβ-CEZ and Ti-6Al-4V(TC4)alloys in NaNO3solution are discussed.The open circuit potential(OCP),Tafel polarization,potentiodynamic polarization,electrochemical impedance spectroscopy(EIS),and current efficiency curves of theβ-CEZ and TC4 alloys are analyzed.The results show that,compared to the TC4 alloy,the passivation film structure is denser and the charge transfer resistance in the dissolution process is greater for theβ-CEZ alloy.Moreover,the dissolved surface morphology of the two titanium-based alloys under different current densities are analyzed.Under low current densities,theβ-CEZ alloy surface comprises dissolution pits and dissolved products,while the TC4 alloy surface comprises a porous honeycomb structure.Under high current densities,the surface waviness of both the alloys improves and the TC4 alloy surface is flatter and smoother than theβ-CEZ alloy surface.Finally,the electrochemical dissolution models ofβ-CEZ and TC4 alloys are proposed.

ROC分析技术在机器学习中的应用

ROC(Return-Of-Certain)分析是一种通过比较决策和行动的结果预测系统性能的技术。当系统被嵌入一个大数据集中时,其性能可能会发生变化,从而需要重新分析其决策和行动结果。在机器学习领域,ROC分析技术是一种用于分析和改进机器学习算法性能的工具,可对比模型的决策结果与实际结果,以确定其准确性、鲁棒性和有效性。

基于Logistic回归模型及ROC曲线的糖尿病足溃疡复发的危险因素分析

目的基于Logistic回归模型及ROC曲线的糖尿病足溃疡(DFU)复发的危险因素分析。方法回顾性选取2018年9月—2019年9月本院收治的92例初发2型糖尿病(T2DM)足溃疡患者,根据3年内足溃疡复发情况分为非复发组51例与复发组41例,行DFU患者足溃疡复发的单因素分析,多因素Logistic模型研究DFU患者足溃疡复发的危险因素,Spearman检验分析各指标与DFU患者足溃疡复发的相关性,受试者工作特征曲线(ROC)评价模型诊断效能。结果92例DFU患者随访3年,复发41例,复发率为44.57%。单因素分析显示,两组体质量指数(BMI)、性别、心脑血管疾病病史占比、高血压病史占比、住院时间、发病至就诊时间、ALB、TBIL、Scr、HbA1c、TG、HDL、TC、LDL差异无统计学意义(P>0.05);与非复发组比较,复发组年龄、T2DM病程、糖尿病周围神经病变(DPN)占比、下肢外周动脉病变(PAD)占比、吸烟史占比、创面位于胼胝占比明显升高,TBIL水平明显降低(均P<0.05)。多因素分析显示,年龄增大、T2DM病程长、合并DPN、合并PAD、有吸烟史、创面位于胼胝及血清TBIL水平降低为DFU患者足溃疡复发的危险因素(P<0.05)。Spearman检验提示,DFU患者足溃疡复发与年龄、T2DM病程、DPN、PAD、吸烟史、创面位于胼胝呈正相关,TBIL水平明显降低呈负相关(均P<0.05)。以unite(七变量综合)、年龄、T2DM病程、TBIL、DPN、PAD、吸烟、创面位于胼胝为检验变量绘制ROC曲线,结果显示,unite的AUC值为0.834,分别大于年龄(0.632)、T2DM病程(0.619)、TBIL(0.645)、DPN(0.684)、PAD(0.662)、吸烟(0.640)、创面位于胼胝(0.677),提示7项指标联合应用于评估DFU患者足溃疡复发的效能明显优于单一指标(P<0.05)。结论年龄增大、T2DM病程长、合并DPN、合并PAD、有吸烟史、创面位于胼胝、血清TBIL水平降低为DFU患者足溃疡复发的危险因素,如发现上述情况应高度警惕DFU患者足溃疡复发风险,并尽早干预。

上海市远郊60岁及以上人群代谢综合征趋势分析及ROC曲线预测

目的:分析上海市远郊60岁及以上人群代谢综合征患病情况及变化趋势,比较血糖、身体质量指数对代谢综合征的评价作用,为相关部门制定代谢综合征防控措施提供参考依据。方法:2022—2023年,选取在上海市金山区高新区社区参与健康体检的19576名老年居民进行问卷调查、身体测量、生物样本采集。结果:参与体检的老年居民中,70~74岁年龄段人群代谢综合征患病率最高(24.8%),≥80岁年龄段人群代谢综合征患病率最低(17.8%);在代谢综合征组分数量方面,65~69岁年龄段人群包含1~4项的组分数量占比均为最高;男性空腹血糖、身体质量指数切点分别为6.05 mmol/L、25.0 kg/m2,ROC曲线下面积分别为0.720和0.824;女性葡萄糖、身体质量指数切点分别为5.92 mmol/L、25.0 kg/m2,ROC曲线下面积分别为0.714和0.798。结论:身体质量指数、空腹血糖是预测社区老年居民代谢综合征的重要变量,相关部门应重视身体质量指数、空腹血糖评估对社区居民代谢综合征的预测价值。

基于ROC分析及样本熵的轴承故障检测

轴承故障检测对旋转机械的维护至关重要。尽管已有的故障诊断方法取得了长足的进步,但仍然面临着一些挑战,如缺乏足够的故障数据用于训练,对复杂的分布式数据的有效性不高,对早期故障的敏感性低,以及噪声和离群值的干扰。因此,本文提出了一种基于样本熵和ROC分析的故障检测方法,通过提取振动信号的样本熵指标,然后使用ROC分析对其进行检测。实验结果表明,本文所提方法能够以较高的准确率检测轴测故障。

Method for determining the position of landslide slip-surface with a typical inclinometric curves

In the actual monitoring of deep hole displacement,the identification of slip surfaces is primarily based on abrupt changes observed in the inclinometric curve.In conventional identification methods,inclinometric curves exhibiting indications of sliding can be categorized into three types:B-type,D-type,and r-type.The position of the slip surface is typically determined by identifying the depth corresponding to the point of maximum displacement mutation.However,this method is sensitive to the interval of measurement points and the observation scale of the coordinate axes and suffers from unclear sliding surfaces and uncertain values.Based on the variation characteristics of these diagonal curves,we classified the landslide into three components:the sliding body,the sliding interval,and the immobile body.Moreover,three different generalization models were established to analyze the relationships between the curve form and the slip surface location based on different physical indicators such as displacement rate,relative displacement,and acceleration.The results show that the displacement rate curves of an r-type slope exhibit a clustering feature in the sliding interval,and by solving for the depth of discrete points within the step phase,it is possible to determine the location of the slip surface.On the other hand,D-type slopes have inflection points in the relative displacement curve located at the slip surface.The acceleration curves of B-type slopes exhibit clustering characteristics during the sliding interval,while the scattered acceleration data demonstrate wandering characteristics.Consequently,the slip surface location can be revealed by solving the depth corresponding to the maximum acceleration with cubic spline interpolation.The approach proposed in this paper was applied to the monitoring data of a landslide in Yunnan Province,China.The results indicate that our approach can accurately identify the slip surface location and enable computability of its position,thereby enhancing applicability and reliability of the deep-hole displacement monitoring data.

Performance and Application of Double-layered Microcapsule Corrosion Inhibitors

Double-layered microcapsule corrosion inhibitors were developed by sodium monofluorophosphate as the core material,polymethyl methacrylate as the inner wall material,and polyvinyl alcohol as the outer wall material combining the solvent evaporation method and spray drying method.The protection by the outer capsule wall was used to prolong the service life of the corrosion inhibitor.The dispersion,encapsulation,thermal stability of microcapsules,and the degradation rate of capsule wall in concrete pore solution were analyzed by ultra-deep field microscopy,scanning electron microscopy,thermal analyzer,and sodium ion release rate analysis.The microcapsules were incorporated into mortar samples containing steel reinforcement,and the effects of double-layered microcapsule corrosion inhibitors on the performance of the cement matrix and the actual corrosion-inhibiting effect were analyzed.The experimental results show that the double-layered microcapsules have a moderate particle size and uniform distribution,and the capsules were completely wrapped.The microcapsules as a whole have good thermal stability below 230 ℃.The monolayer membrane structure microcapsules completely broke within 1 day in the simulated concrete pore solution,and the double-layer membrane structure prolonged the service life of the microcapsules to 80 days in the simulated concrete pore solution before the core material was completely released.The mortar samples containing steel reinforcement incorporated with the double-layered microcapsule corrosion inhibitors still maintained a higher corrosion potential than the monolayer microcapsule corrosion inhibitors control group at 60 days.The incorporation of double-layered microcapsules into the cement matrix has no significant adverse effect on the setting time and early strength.

Research into Applicability of Wöhler Curve Method for Low-Cycle Fatigue of Metallic Materials

Recently,a description on a practicability of the Wöhler Curve Method for low-cycle fatigue of metals was given by the author.By the description and the low cycle fatigue test data of 16 MnR steel,it is important to show that,for low cycle fatigue of metals,such a way that a stress-based intensity parameter calculated by the linear-elastic analysis is taken to be a stress intensity parameter,S,to establish a relationship between the stress intensity parameter,S,and the fatigue life,N,is practicable.In this paper,many metallic materials from the literature are given to show that the Wöhler Curve Method is well suitable for low-cycle fatigue analysis of metals.

Research on batch multielement rapid quantitative analysis based on the standard curve-assisted calibration-free laserinduced breakdown spectroscopy method

This study proposes a batch rapid quantitative analysis method for multiple elements by combining the advantages of standard curve(SC)and calibration-free laser-induced breakdown spectroscopy(CF-LIBS)technology to achieve synchronous,rapid,and accurate measurement of elements in a large number of samples,namely,SC-assisted CF-LIBS.Al alloy standard samples,divided into calibration and test samples,were applied to validate the proposed method.SC was built based on the characteristic line of Pb and Cr in the calibration sample,and the contents of Pb and Cr in the test sample were calculated with relative errors of 6%and 4%,respectively.SC built using Cr with multiple characteristic lines yielded better calculation results.The relative contents of ten elements in the test sample were calculated using CF-LIBS.Subsequently,the SC-assisted CF-LIBS was executed,with the majority of the calculation relative errors falling within the range of 2%-5%.Finally,the Al and Na contents of the Al alloy were predicted.The results demonstrate that it effectively enables the rapid and accurate quantitative analysis of multiple elements after a single-element SC analysis of the tested samples.Furthermore,this quantitative analysis method was successfully applied to soil and Astragalus samples,realizing an accurate calculation of the contents of multiple elements.Thus,it is important to advance the LIBS quantitative analysis and its related applications.

Quantum dynamics within curved thin layers with deviation

Combining the deviation between thin layers' adjacent surfaces with the confining potential method applied to the quantum curved systems,we derive the effective Schr?dinger equation describing the particle constrained within a curved layer,accompanied by a general geometric potential V_(gq) composed of a compression-corrected geometric potential V_(gq)~*and a novel potential V_(gq)~(**) brought by the deviation.Applying this analysis to the cylindrical layer emerges two types of deviation-induced geometric potential,resulting from the the cases of slant deviation and tangent deviation,respectively,which strongly renormalizes the purely geometric potential and contribute to the energy spectrum based on a very substantial deepening of bound states they offer.

A Non-Parametric Scheme for Identifying Data Characteristic Based on Curve Similarity Matching

For accurately identifying the distribution charac-teristic of Gaussian-like noises in unmanned aerial vehicle(UAV)state estimation,this paper proposes a non-parametric scheme based on curve similarity matching.In the framework of the pro-posed scheme,a Parzen window(kernel density estimation,KDE)method on sliding window technology is applied for roughly esti-mating the sample probability density,a precise data probability density function(PDF)model is constructed with the least square method on K-fold cross validation,and the testing result based on evaluation method is obtained based on some data characteristic analyses of curve shape,abruptness and symmetry.Some com-parison simulations with classical methods and UAV flight exper-iment shows that the proposed scheme has higher recognition accuracy than classical methods for some kinds of Gaussian-like data,which provides better reference for the design of Kalman filter(KF)in complex water environment.

Bending results of graphene origami reinforced doubly curved shell

The present work investigates higher order stress,strain and deformation analyses of a shear deformable doubly curved shell manufactures by a Copper(Cu)core reinforced with graphene origami auxetic metamaterial subjected to mechanical and thermal loads.The effective material properties of the graphene origami auxetic reinforced Cu matrix are developed using micromechanical models cooperate both material properties of graphene and Cu in terms of temperature,volume fraction and folding degree.The principle of virtual work is used to derive governing equations with accounting thermal loading.The numerical results are analytically obtained using Navier's technique to investigate impact of significant parameters such as thermal loading,graphene amount,folding degree and directional coordinate on the stress,strain and deformation responses of the structure.The graphene origami materials may be used in aerospace vehicles and structures and defence technology because of their low weight and high stiffness.A verification study is presented for approving the formulation,solution methodology and numerical results.

A Tutorial Review of the Solar Power Curve: Regressions, Model Chains, and Their Hybridization and Probabilistic Extensions

Owing to the persisting hype in pushing toward global carbon neutrality,the study scope of atmospheric science is rapidly expanding.Among numerous trending topics,energy meteorology has been attracting the most attention hitherto.One essential skill of solar energy meteorologists is solar power curve modeling,which seeks to map irradiance and auxiliary weather variables to solar power,by statistical and/or physical means.In this regard,this tutorial review aims to deliver a complete overview of those fundamental scientific and engineering principles pertaining to the solar power curve.Solar power curves can be modeled in two primary ways,one of regression and the other of model chain.Both classes of modeling approaches,alongside their hybridization and probabilistic extensions,which allow accuracy improvement and uncertainty quantification,are scrutinized and contrasted thoroughly in this review.