A three-dimensional(3D)analytical formulation is proposed to put together magnetic,electric and elastic fields to analyze the vibration modes of simply-supported layered piezo-electro-magnetic plates.The present 3D mo...A three-dimensional(3D)analytical formulation is proposed to put together magnetic,electric and elastic fields to analyze the vibration modes of simply-supported layered piezo-electro-magnetic plates.The present 3D model allows analyses for layered smart plates in both open-circuit and closed-circuit configurations.The secondorder differential equations written in the mixed curvilinear reference system govern the magneto-electro-elastic free vibration problem for multilayered plates.This set consists of the 3D equations of motion and the 3D divergence equations for the magnetic induction and electric displacement.Navier harmonic forms in the planar directions and the exponential matrix method in the transversal direction of the plate are applied to solve the second-order differential equations in terms of displacements.For these reasons,simply-supported boundary conditions are considered.Imposition of interlaminar continuity conditions on primary variables(displacements,magnetic potential,electric potential),and some secondary variables(transverse normal and transverse shear stresses,transverse normal magnetic induction/electric displacement)allows the implementation of the layer-wise approach.Assessments for both load boundary configurations are proposed in the results section to validate the present 3D approach.3D electro-elastic and 3D magneto-elastic coupling validations are performed separately considering different models from the open literature.A new benchmark involving a full magneto-electro-elastic coupling for multilayered plates is presented considering both load boundary configurations for different thickness ratios.For this benchmark,circular frequency values and related vibration modes through the transverse direction in terms of displacements,magnetic and electric potential,transverse normal magnetic induction/electric displacement are shown to visualize the magneto-electroelastic coupling and material and thickness layer effects.The present formulation has been entirely implemented in an academic Matlab(R2024a)code developed by the authors.In this paper,for the first time,the second-order differential equations governing the magneto-electro-elastic problem for the free vibration analysis of plates has been solved considering the mixed mode of harmonic forms and exponential matrix.The exponential matrix permits computing the secondary variable of the problem(stresses,electric displacement components and magnetic induction components)exactly,directly from constitutive and geometrical equations.In addition,the very simple and elegant formulation permits having a code with very low computational costs.The present manuscript aims to fill the void in open literature regarding reference 3D solutions for the free vibration analysis of magneto-electro-elastic plates.展开更多
目的探讨不同严重程度急性呼吸窘迫征(ARDS)患者血清1,25-二羟维生素D3[1,25-(OH)_(2)D_(3)]水平变化及其与预后的关系。方法将150例ARDS患者根据氧合指数分为轻度组(200 mm Hg<氧合指数≤300 mm Hg,54例)、中度组(100 mm Hg<氧...目的探讨不同严重程度急性呼吸窘迫征(ARDS)患者血清1,25-二羟维生素D3[1,25-(OH)_(2)D_(3)]水平变化及其与预后的关系。方法将150例ARDS患者根据氧合指数分为轻度组(200 mm Hg<氧合指数≤300 mm Hg,54例)、中度组(100 mm Hg<氧合指数≤200 mm Hg,50例)、重度组(氧合指数≤100 mm Hg,46例)。根据预后情况再将其分为预后良好组(98例)与预后不良组(52例)。收集所有患者的一般资料、临床资料及实验室检查指标并分组进行比较。采用多元线性回归分析不同严重程度组ARDS患者1,25-(OH)_(2)D_(3)与炎症反应指标的相关性。采用多因素logistic回归分析评估影响ARDS患者预后的相关因素。采用共线性诊断检验自变量间的共线性。采用cox比例风险模型调整混杂变量后,分析1,25-(OH)_(2)D_(3)与炎症反应指标对ARDS患者预后的交互作用。采用logistic回归模型结合限制性立方样条模型(RCS)评估1,25-(OH)_(2)D_(3)和不同严重程度的ARDS患者预后的剂量-反应关系。结果轻度组、中度组、重度组患者1,25-(OH)_(2)D_(3)水平依次降低,急性生理和慢性疾病(APACHEⅡ)评分、脓毒症相关器官衰竭(SOFA)评分、降钙素原(PCT)、N末端B型脑钠肽前体(NT-proBNP)、C反应蛋白(CRP)、WBC计数、碱性成纤维细胞生长因子2(FGF2)、肿瘤坏死因子-α(TNF-α)、IL-6、IL-1β水平均依次升高(P<0.05)。多元线性回归分析结果显示,调整了相关因素后不同严重程度组ARDS患者TNF-α、IL-6、IL-1β均与1,25-(OH)_(2)D_(3)呈独立负相关(P<0.05)。预后不良组患者氧合指数及1,25-(OH)_(2)D_(3)水平均低于预后良好组,APACHEⅡ评分、SOFA评分、PCT、NT-proBNP、CRP、WBC计数、FGF2、TNF-α、IL-6、IL-1β水平均高于预后良好组(P<0.05)。多因素logistic回归分析结果显示,APACHEⅡ评分、氧合指数、FGF2、PCT、NT-proBNP、SOFA评分、1,25-(OH)_(2)D_(3)、TNF-α、IL-6、IL-1β均是影响ARDS患者预后的独立因素(P<0.05)。共线性诊断检验结果提示变量之间相互独立,不存在共线性。交互作用分析结果显示,相加及相乘模型中,1,25-(OH)_(2)D_(3)与TNF-α、IL-6、IL-1β对ARDS患者预后的影响均存在交互作用。RCS模型分析结果显示,1,25-(OH)_(2)D_(3)水平与轻度组、中度组、重度组ARDS患者预后不良发生风险均呈非线性相关(P_(非线性)=0.046、0.042、0.048)。结论血清1,25-(OH)_(2)D_(3)水平能够用来判断ARDS患者的病情严重程度,且1,25-(OH)_(2)D_(3)对ARDS患者预后具有一定的预测价值。展开更多
文摘A three-dimensional(3D)analytical formulation is proposed to put together magnetic,electric and elastic fields to analyze the vibration modes of simply-supported layered piezo-electro-magnetic plates.The present 3D model allows analyses for layered smart plates in both open-circuit and closed-circuit configurations.The secondorder differential equations written in the mixed curvilinear reference system govern the magneto-electro-elastic free vibration problem for multilayered plates.This set consists of the 3D equations of motion and the 3D divergence equations for the magnetic induction and electric displacement.Navier harmonic forms in the planar directions and the exponential matrix method in the transversal direction of the plate are applied to solve the second-order differential equations in terms of displacements.For these reasons,simply-supported boundary conditions are considered.Imposition of interlaminar continuity conditions on primary variables(displacements,magnetic potential,electric potential),and some secondary variables(transverse normal and transverse shear stresses,transverse normal magnetic induction/electric displacement)allows the implementation of the layer-wise approach.Assessments for both load boundary configurations are proposed in the results section to validate the present 3D approach.3D electro-elastic and 3D magneto-elastic coupling validations are performed separately considering different models from the open literature.A new benchmark involving a full magneto-electro-elastic coupling for multilayered plates is presented considering both load boundary configurations for different thickness ratios.For this benchmark,circular frequency values and related vibration modes through the transverse direction in terms of displacements,magnetic and electric potential,transverse normal magnetic induction/electric displacement are shown to visualize the magneto-electroelastic coupling and material and thickness layer effects.The present formulation has been entirely implemented in an academic Matlab(R2024a)code developed by the authors.In this paper,for the first time,the second-order differential equations governing the magneto-electro-elastic problem for the free vibration analysis of plates has been solved considering the mixed mode of harmonic forms and exponential matrix.The exponential matrix permits computing the secondary variable of the problem(stresses,electric displacement components and magnetic induction components)exactly,directly from constitutive and geometrical equations.In addition,the very simple and elegant formulation permits having a code with very low computational costs.The present manuscript aims to fill the void in open literature regarding reference 3D solutions for the free vibration analysis of magneto-electro-elastic plates.
文摘目的探讨不同严重程度急性呼吸窘迫征(ARDS)患者血清1,25-二羟维生素D3[1,25-(OH)_(2)D_(3)]水平变化及其与预后的关系。方法将150例ARDS患者根据氧合指数分为轻度组(200 mm Hg<氧合指数≤300 mm Hg,54例)、中度组(100 mm Hg<氧合指数≤200 mm Hg,50例)、重度组(氧合指数≤100 mm Hg,46例)。根据预后情况再将其分为预后良好组(98例)与预后不良组(52例)。收集所有患者的一般资料、临床资料及实验室检查指标并分组进行比较。采用多元线性回归分析不同严重程度组ARDS患者1,25-(OH)_(2)D_(3)与炎症反应指标的相关性。采用多因素logistic回归分析评估影响ARDS患者预后的相关因素。采用共线性诊断检验自变量间的共线性。采用cox比例风险模型调整混杂变量后,分析1,25-(OH)_(2)D_(3)与炎症反应指标对ARDS患者预后的交互作用。采用logistic回归模型结合限制性立方样条模型(RCS)评估1,25-(OH)_(2)D_(3)和不同严重程度的ARDS患者预后的剂量-反应关系。结果轻度组、中度组、重度组患者1,25-(OH)_(2)D_(3)水平依次降低,急性生理和慢性疾病(APACHEⅡ)评分、脓毒症相关器官衰竭(SOFA)评分、降钙素原(PCT)、N末端B型脑钠肽前体(NT-proBNP)、C反应蛋白(CRP)、WBC计数、碱性成纤维细胞生长因子2(FGF2)、肿瘤坏死因子-α(TNF-α)、IL-6、IL-1β水平均依次升高(P<0.05)。多元线性回归分析结果显示,调整了相关因素后不同严重程度组ARDS患者TNF-α、IL-6、IL-1β均与1,25-(OH)_(2)D_(3)呈独立负相关(P<0.05)。预后不良组患者氧合指数及1,25-(OH)_(2)D_(3)水平均低于预后良好组,APACHEⅡ评分、SOFA评分、PCT、NT-proBNP、CRP、WBC计数、FGF2、TNF-α、IL-6、IL-1β水平均高于预后良好组(P<0.05)。多因素logistic回归分析结果显示,APACHEⅡ评分、氧合指数、FGF2、PCT、NT-proBNP、SOFA评分、1,25-(OH)_(2)D_(3)、TNF-α、IL-6、IL-1β均是影响ARDS患者预后的独立因素(P<0.05)。共线性诊断检验结果提示变量之间相互独立,不存在共线性。交互作用分析结果显示,相加及相乘模型中,1,25-(OH)_(2)D_(3)与TNF-α、IL-6、IL-1β对ARDS患者预后的影响均存在交互作用。RCS模型分析结果显示,1,25-(OH)_(2)D_(3)水平与轻度组、中度组、重度组ARDS患者预后不良发生风险均呈非线性相关(P_(非线性)=0.046、0.042、0.048)。结论血清1,25-(OH)_(2)D_(3)水平能够用来判断ARDS患者的病情严重程度,且1,25-(OH)_(2)D_(3)对ARDS患者预后具有一定的预测价值。
文摘目的探索人工智能辅助压缩感知(artificial intelligence-assisted compressed sensing,ACS)技术加速颅内血管壁高分辨率三维T1加权黑血成像(three-dimensional T1-weighted black blood imaging,3D T1_HRVWI)的可行性,并与临床常规采用的并行采集技术(parallel imaging,PI)进行对比分析。方法前瞻性纳入47例脑血管疾病患者,行ACS加速(实验组)和PI加速(对照组)的3D T1_HRVWI扫描。客观比较ACS组和PI组的序列扫描时长、图像中血管壁的信噪比以及相对于血管腔的对比噪声比,主观评估两组图像总体质量、颅内血管显示情况及病灶诊断价值,并进行统计分析。结果相较于PI 3D T1_HRVWI,ACS 3D T1_HRVWI的扫描时长缩短43%;ACS 3D T1_HRVWI图像中颈内动脉、基底动脉、椎动脉、大脑前动脉、大脑中动脉、大脑后动脉血管壁的信噪比均显著升高(P<0.001);两组图像的总体质量评分和颅内血管的显示评分均未见显著差异(P>0.05);两组图像的病灶诊断价值相当(P>0.05)。结论ACS技术实现了3D T1_HRVWI序列更快的采集速度,同时保持了较好的成像质量,为开发兼顾扫描效率与诊断精度的脑血管影像扫描方案提供了循证依据,在脑血管疾病的精准诊断中展现出重要价值。
