An analytical study of vibration in functionally graded piezoelectric nanoplates: nonlocal strain gradient theory

In this paper,we analytically study vibration of functionally graded piezoelectric(FGP)nanoplates based on the nonlocal strain gradient theory.The top and bottom surfaces of the nanoplate are made of PZT-5H and PZT-4,respectively.We employ Hamilton’s principle and derive the governing differential equations.Then,we use Navier’s solution to obtain the natural frequencies of the FGP nanoplate.In the first step,we compare our results with the obtained results for the piezoelectric nanoplates in the previous studies.In the second step,we neglect the piezoelectric effect and compare our results with those obtained for the functionally graded(FG)nanoplates.Finally,the effects of the FG power index,the nonlocal parameter,the aspect ratio,and the lengthto-thickness ratio,and the nanoplate shape on natural frequencies are investigated.

The Application of Multiquadric Function Fitting to Borehole Strain Time Series Data Processing

Based on the existing continuous borehole strain observation,the multiquadric function fitting method was used to deal with time series data. The impact of difference kernel function parameters was discussed to obtain a valuable fitting result,from which the physical connotation of the original data and its possible applications were analyzed.Meanwhile,a brief comparison was made between the results of multiquadric function fitting and polynomial fitting.

Assessment of Left Ventricular Longitudinal Regional Myocardial Systolic Function by Strain Imaging Echocardiography in Patients with Hypertrophic Cardiomyopathy

To assess the left ventricular longitudinal regional myocardial systolic function by strain imaging （SI） echocardiography and to study the relationship between regional myocardial systolic function and left ventricular structure in patients with hypertrophic cardiomyopathy （HCM）. S1 echocardiography were performed in 18 patients with HCM and 17 healthy subjects. For each wall, regional myocardial systolic strain was analyzed at the basal, mid, and apical level respectively. And the peak systolic strain was measured. Our results showed that the patients with HCM had reduced peak systolic strain at almost each segment of different walls when compared with healthy subjects. There was significant correlation between the mid-septum peak systolic strain and the thickness of IVS, so was the correlation between the mid-septum peak systolic strain and the IVS to LVPW thickness ratio. This study demonstrated that the left ventricular longitudinal regional myocardial systolic function was abnormal in HCM, and this kind of abnormalities existed extensively in hypertrophic and non-hypertrophic cardiac segments. The degrees of left ventricle hypertrophy and asymmetry are related to the myocardial regional systolic function in HCM.

Uncertainty analysis of strain modal parameters by Bayesian method using frequency response function

Structural strain modes are able to detect changes in local structural performance, but errors are inevitably intermixed in the measured data. In this paper, strain modal parameters are considered as random variables, and their uncertainty is analyzed by a Bayesian method based on the structural frequency response function （FRF）. The estimates of strain modal parameters with maximal posterior probability are determined. Several independent measurements of the FRF of a four-story reinforced concrete flame structural model were performed in the laboratory. The ability to identify the stiffness change in a concrete column using the strain mode was verified. It is shown that the uncertainty of the natural frequency is very small. Compared with the displacement mode shape, the variations of strain mode shapes at each point are quite different. The damping ratios are more affected by the types of test systems. Except for the case where a high order strain mode does not identify local damage, the first order strain mode can provide an exact indication of the damage location.

Assessment of Regional Myocardial Function in Patients with Hypertrophic Cardiomyopathy by Tissue Strain Imaging

The value of tissue strain imaging （SI） in regional myocardial systolic and diastolic func tion assessment was studied. In 18 patients with nonobstructive hypertrophic cardiomyopathy （HCM） and 20 age-matched healthy subjects, regional myocardial longitudinal peak systolic strain in eject time （represented by εet） was measured at basal, mid and apical segments of septal, lateral and posterior walls of the left ventricle （LV） and compared between groups, εet had no significant difference between segments in control group （P〉0.05）, which displayed a decreasing trend from basal segments to apical ones. εet in the HCM group was significantly decreased （P（0. 05） as compared with that in the healthy group. In the HCM group, εet in the midseptum was significantly less than at the basal and apical septum, and was also less than at the rest LV walls in the same group （P〉0.01）. The systolic reversed εet was noticed in 35% of the hypertrophic segments in HCM group. Significantly negative correlation existed between the absolute value of εet and wall thickness in the midseptum （r= -0.83）. The post-systolic strain（PSS） segment number the and amplitudes in healthy group were significantly less than those in HCM group （P〈0.05）. Both regional myocardial systolic and diastolic functions were impaired in hypertrophic or non-hypertrophic segments in patients with the HCM, especially in hypertrophic segments. Strain imaging technique is a sensitive and accura tool in myocardial dysfunction assessment.

QUANTIFICATION OF RIGHT VENTRICULAR FUNCTION IN ATRIAL SEPTAL DEFECT USING ULTRASOUND- BASED STRAIN RATE IMAGING

Objective To study the validation of ultrasound-based strain rate imaging in the quantitative assessment of right ventricular （RV） function in atrial septal defect （ASD）. Methods Tissue Doppler images （TDI） of RV longitudinal and short axes were recorded from the apical 4-chamber view and the subcostal short-axis view in 18 normal controls, 28 children with ASD and 14 children after Amplazter closure of ASD respectively. Peak systolic velocities （ V）, peak systolic strain rates （SR）, peak systolic strains （S） at the basal segment, middle segment of RV lateral wall and the basal septum from the longitudinal axis, the middle segment of RV free waU from the short axis were quantitatively measured using QLAB^TM tissue velocity quantification software system respectively. Peak dp/ dt from the RV isovolumic contraction determined during the right cardiac catheterization in 28 ASD patients was used as the gold standard of RV contractility. Peak systolic indices were compared against max dp/dt by linear correlation, Results Peak systolic indices at the basal and middle segments of RV lateral wall from the longitudiual axis increased significantly in 28 ASD patients. Peak systolic indices at the basal septum also increased in patient group, but not significantly. Significant decreases in peak systolic indices at the basal and middle segments of RV lateral wall were observed after the Amplatzer closure in 14 ASD patients. There was no significant difference at the middle segment of RV free wall from the short axis between patient group and normal control. A strong correlation was found between max dp/dt and peak systolic indices at the basal and middle segments of RV lateral wal l （ P 〈 0. 05 ）. Conclusion Ultrasound-based strain rate imaging can assess quantitatively RVfunction in CHD. Peak systolic strains determined at the basal and middle segments of RV lateral wall are strong noninvasive indices of RV contractility.

Assessment of Myocardial Perfusion and Systolic Function in Patients with Coronary Artery Disease after Coronary Artery Bypass Surgery by Myocardial Contrast Echocardiography and Two-dimensional Strain Echocardiography

The clinically applied value of myocardial perfusion and systolic function in patients with coronary artery disease after coronary artery bypass surgery using real-time myocardial contrast echocardiography （RT-MCE） combined with two-dimensional strain echocardiography was assessed. Twenty patients underwent intravenous RT-MCE by intravenous injections of SonoVue before and after coronary artery bypass surgery. Two-dimensional images were recorded from the left ventricular four-chamber view, two-chamber view and the apical view before, and two weeks and three months after coronary artery bypass surgery, and the peak systolic longitudinal strain was measured. The results showed that myocardial perfusion was significantly increased after coronary artery bypass surgery in about 71.6% segments. In the group that myocardial perfusion was improved, the peak systolic longitu- dinal strain three months after bypass surgery was significantly higher than that before operation [（-15.78±5.91）% vs （-10.45±8.31）%, P〈0.05]. However, the parameters did not change in the group without myocardial perfusion improvement [（-10.33±6.53）% vs （-9.41±6.09）%, P〉0.05]. It was concluded that whether or not the improvement of myocardial perfusion can mirror the recovery trend of regional systolic function, two-dimensional strain echocardiography can observe dynamic change of regional systolic function. The combination of myocardial perfusion with two-dimensional strain echocardiography can more accurately assess the curative effectiveness of coronary artery bypass surgery.

Evaluation of Sub Clinical Myocardial Systolic Dysfunction Using 2D Global Longitudinal Strain Assessment in Type 2 Diabetes Patients in Sub-Saharan Africa

Background: Heart failure is the commonest cardiovascular complication in type 2 diabetes mellitus. However, subclinical left ventricular dysfunction can’t be detected using 2D echocardiography which is routinely used for cardiac evaluation of diabetic patients. We aimed to determine the prevalence and factors associated to left ventricular global longitudinal strain (LV GLS) impairment in type 2 diabetes Cameroonians patients. Methods: We conducted a cross-sectional study from January 2019 to June 2019, including type 2 diabetes patients with preserved left ventricle ejection fraction. Clinical and echocardiographic data were collected, and LV GLS was assessed using speckle tracking technique, a value ≤ -16% been considered as normal value. Results: We recruited 95 patients, with a mean age of 57.4 ± 11.8 years old and median diabetes duration of 5 [2 - 12] years. Echocardiographic evaluation found 56.3% of left ventricle remodelling, 51.6% of left ventricle diastolic dysfunction and mean left ventricle ejection of 63.3% ± 6.6%. LV GLS impairment was present in 43.2% (95% CI: 32.6 - 53.7) of the participants. After adjustment to all significantly associated factors, Obesity (aOR: 4;95% CI: 1.5 - 10.6) and diastolic dysfunction (aOR: 3.1;95% CI: 1.2 - 8.2) were independent factors associated with LV GLS. Conclusions: Subclinical systolic dysfunction assessed by LV GLS impairment is frequent in diabetic patients. Further research should be carried out more extensively to integrate LV GLS in the type 2 diabetes patients’ routine follow up for a better prognostic outcome, especially in low-incomes countries.

Diet and Rat Strain as Factors in Nervous System Function and Influence of Confounders

The necessity for understanding normal human cognitive processes and behavior, and themechanisrns which result in dysfunction in these processes are dependant on utilization of a suitable animal model. In order to develop pharmaceutical agents to alleviate mental disturbances and enable the individual to cope within the norms of society, it is incumbent upon investigators to choose a species in which pharmacokinetic principles are established and resemble those of hurnans. The choice of rats in cognition research studies has specific advantages in that these anirnals possess similar pharrnacodynamic parameters to hurnans. Further advantages include availability, low cost, ease of breeding, maintenance and an extensive literature database which enable comparisons to present findings. However, there are substantial differences in the perforrnance of various rat strains in tasks of learning, memory, attention, and responses to stress or drugs. In addition to rat strain, quantity of thed also exerts profound consequences on animal behavior. The aim of this review is to demonstrate that there are differences in the central nervous systern responsivencess of rat strains to chemicals and these could be related to factors such as source of supplier, type and quantity of feed, or season of the year. It is also evident that the genotype differs amongst strains and this may be responsible for the observed differences in CNS sensitivity to chemicals. Strain differences must be identified and taken into consideration in interpretation of assessrnent of neurobehavioural functions. It is also incumbent upon the investigators to utilize healthy (diet-controlled) animal models.

The Effect of Percutaneous Coronary Intervention on Left Ventricular Diastolic Dysfunction in Patients with Coronary Artery Disease Assessed by Strain Rate Imaging

Introduction: Coronary artery disease (CAD) is the most common cause for left ventricular dysfunction. Unfortunately, the treatment strategies of regional myocardial diastolic dysfunction in patients with CAD have not been well characterized and benefit of percutaneous coronary intervention (PCI) as a treatment strategy is not clear. So the present study aimed to assess the effects of PCI on regional and global left ventricular diastolic dysfunction in patients with CAD assessed by strain rate (SR) imaging. Methods: Thirty adult symptomatic patients with coronary artery disease that underwent coronary angiography and candidate for PCI on left anterior descending artery were enrolled to our study. Echocardiographic findings and early diastolic SR were measured before and 48 hours after PCI. Results: Mean age of the patients was 59.9 ± 8.3 years. Most of the left ventricular diastolic parameters showed significant difference before and after elective PCI;while mitral E velocity, DT, E/A and pulmonary vein flow before and after PCI did not show significant difference assessed by statically test. Also before PCI, mean (SD) of peak early diastolic SR in ischemic regions (1.89 ± 0.22) was smaller than of non-ischemic regions (2.53 ± 0.26) while after PCI this parameter became similar in ischemic regions (2.55 ± 0.27) and non-ischemic regions (2.55 ± 0.26). Conclusion: Most of the left ventricular diastolic parameters improved after PCI in CAD patients. Also regional myocardial relaxation as measured by peak early diastolic SR (ESR) in the ischemic segments improved significantly compared with that in non-ischemic segments.

左室压力-应变环定量评估甲状腺功能亢进患者左室心肌做功改变的应用价值

目的 探讨左室压力-应变环(left ventricular pressure-strain loop,LV-PSL)定量评估甲状腺功能亢进患者左室心肌做功改变的应用价值。方法 选取2021年8月—2023年8月在南宁市第二人民医院45例确诊为甲状腺功能亢进的患者为研究对象,根据甲亢程度分为A组(临床甲亢,n=33)与B组(亚临床甲亢,n=12),同期选取健康人群45名作为对照(C组)。收集患者一般资料,应用LVPSL技术获取整体纵向应变(global longitudinal strain,GLS)、整体做功指数(global myocardial work index,GWI)、整体有用功(globalmyocardialconstructivework,GCW)、整体无用功(globalmyocardial wasted work,GWW)及整体做功效率(global myocardial work efficiency,GWE),比较三组间上述参数的差异、血清甲状腺功能指标[促甲状腺激素(thyroid stimulating hormone,TSH)、游离甲状腺素(free thyroxine,FT4)、游离三碘甲腺原氨酸(free triiodothyronine,FT3)]、常规超声心动图指标[左心房内径(left atrial dimension,LAD)、左室后壁厚度(left ventricular posterior wall,LVPW)、舒张末期室间隔厚度(interventricular septal thickness at diastole,IVSD)、左心室舒张末期容积(left ventricular end diastolic volume,LVEDV)、左室收缩末期容积(left ventricular end systolic volume,LVESV)、左室射血分数(left ventricular ejection fractions,LVEF)]。结果 A组TSH[(0.19±0.06)mIU/L]和B组TSH[(0.23±0.02)mIU/L]均低于C组[(2.08±0.36)mIU/L];A组FT4[(25.15±2.18)pmol/L]、FT3[(9.19±1.24)pmol/L]和B组FT4[(20.48±1.98)pmol/L]、FT3[(6.14±0.93)pmol/L]均高于C组FT4[(14.25±1.57)pmol/L]、FT3[(3.14±1.01)pmol/L],差异有统计学意义(F=612.913、304.926、290.891,P均<0.05)。A组和B组甲亢患者与C组的各项常规超声心动图指标比较,差异无统计学意义(P均>0.05)。A组和B组的GLS、GWI、GCW、GWE均低于C组,GWW高于C组,差异有统计学意义(P均<0.05)。结论 LV-PSL可以定量评估甲状腺功能亢进患者的心肌功能改变,不同类型的甲状腺功能亢进患者的甲状腺激素水平存在一定的差异,有利于临床对于甲状腺功能亢进类型的辨别。

特征追踪心脏MRI定量评估非梗阻性肥厚型心肌病左房功能的应用研究

目的:应用特征追踪心脏MRI(FT-cMRI)对非梗阻性肥厚型心肌病(NOHCM)患者进行左房应变分析来评估左心房功能,并探究NOHCM对左心结构和功能的影响。方法:回顾性分析2020年1月-2022年12月本院58例非梗阻性肥厚型心肌病患者(NOHCM组)和30例健康对照者(HC组)的临床和MRI资料。MRI扫描序列主要为单次激发FSE亮血序列,扫描平面包括两腔、四腔和短轴位。应用CVI42软件测量左房容积指数(LAVI)和左房整体功能参数,后者包括心肌储备功能参数[总应变(εs)、峰值正向应变率(SRs)、左房总射血分数(LATEF)]、导管功能参数[主动应变(εe)、峰值早期负向应变率(SRe)、左房被动射血分数(LAPEF)]和升压泵功能参数[被动应变(εa)、峰值晚期负向应变率(SRa)、左房主动射血分数(LAAEF)],以及左室的功能[左室射血分数(LVEF)、左室心输出量(LVCO)和左室心脏指数(LVCI)]和大小参数[左室最大室壁厚度(LVWT_(max))、左室心肌质量(LVM)、左室质量指数(LVMI)、左室舒张末期容积指数(LVEDVi)和左室收缩末期容积指数(LVESVi)]。采用两样本t检验、Mann-Whitney U检验等统计学方法比较两组间各项定量参数值的差异,并采用Pearson或Spearman相关系数分析左房功能参数与左室的结构和功能参数之间的相关性。结果:NOHCM组的LVWT_(max)、LVM、LVMI和LAVI值均显著高于HC组(P<0.05),NOHCM组的左房功能参数值(LATEF、LAPEF、LAAEF、εs、εe、εa,SRs、SRe和SRa)均显著低于HC组(P<0.05)。NOHCM组左室心肌不同肥厚部位的LVWT_(max)的差异有统计学意义(P<0.05),两组之间其它的左房、左室结构和功能参数值的差异无统计学意义(P>0.05)。左房大小正常的NOHCM患者的LATEF、LAPEF、εs、εe、SRs和SRe值均显著低于HC组(P<0.05),而LAAEF、εa和SRa值在两组之间的差异无统计学意义(P>0.05)。所有受试者的LATEF与εs、LAPEF与εe、LAAEF与εa之间均具有显著相关性(r>0.70)。结论:与健康对照组相比,NOHCM患者各时相左房功能均下降。在左房增大之前,左房的心肌储备和导管功能下降,而升压泵功能正常。各时相左房功能受损与左室的肥厚部位无显著相关性。各时相左房的LAEF与各项应变参数之间具有较强的相关性。

Quantification of Regional Left Ventricular Systolic Dysfunction in Patients With Coronary Artery Disease by Strain Rate Imaging

Objectives To detect and compare the systolic strain rate (SR) and strain in the infarct and ischemic myocardium by strain rate imaging (SRI), in order to explore the clinical value of SRI in evaluating regional left ventricular systolic dysfunction. Methods Patients with coronary artery disease were divided into angina pectoris (11 cases) and myocardial infarction (21 cases) groups. Twenty age-matched normal subjects served as the control group. Septal, lateral, anterior, inferior, anteroseptal and posterior walls of the left ventricle were respectively scanned using color tissue Doppler imaging (TDI). Then SR and strain curves were derived from TDI for basal, middle and apical segments of each wall. SRI parameters were: Systolic SR (SRsys), systolic strain (εsys) and maximum strain (εmax). Results Compared with normal segments, SRsys, εsys and εmax decreased significantly in the infarct and ischemic segments (P<0.01). Compared with ischemic segments, SRsys, εsys and εmax decreased significantly in the infarct segments (P<0.05). Conclusions SRsys, εsys and εmax measured by SRI can be used to quantitatively analyze regional left ventricular systolic dysfunction in patients with coronary artery disease, and aid in differentiating infarct from ischemic myocardium.

复配菌株对发酵乳品质与功能特性的改善作用研究进展

发酵乳具有悠久的历史,是经乳酸菌发酵而成的,富含蛋白质、矿物质和维生素等多种营养成分。随着人们对生活品质追求的提高,发酵乳受到消费者越来越多的关注。目前市面上的发酵乳多数是以单菌株或传统乳酸菌(嗜热链球菌和保加利亚乳杆菌)作为发酵剂制备而成的,但是以此生产发酵乳会有发酵时间过长、口感略差和稳定性不佳等问题。近年来,复配菌株作为发酵乳的发酵剂成为发酵乳制备方向的研究热点,利用不同菌株间的互作协同作用,可以有效提高代谢产物的含量和丰富度,进而改善发酵乳的品质及功能特性,弥补传统发酵乳在产品形态以及感官体验等方面的不足。本文综述了复配菌株能够加快发酵乳pH下降速度,丰富产品感官以及改善其流变特性和持水能力,同时还可以增强发酵乳在降血脂、抗炎、抗氧化、抑菌等功能方面的能力。最后展望了发酵乳在未来可以进行创新的研究方向,为今后发酵乳的多元化、功能化、精准化生产提供指导。

苦草附生细菌的分离鉴定及高效功能菌株筛选

为探究沉水植物附生细菌的功能特性,选取苦草(Vallisneria natans)在室内配置模拟污水进行菌群驯化,分离苦草根、叶际附生细菌进行筛选,结合16S rRNA基因序列分析鉴定结果,共分离纯化和保藏172株菌株(分布于5个门、15个目、42个属),其中根际分离菌107株,叶际分离菌65株.将分离得到的5个门、30个属、47个种的82株代表性菌株进行脱氮、解磷释磷、产吲哚乙酸(IAA)和去除有机物功能验证实验.最终筛选到高效氨氮去除菌10株、硝氮去除菌9株、解无机磷菌12株、解有机磷菌11株、产IAA菌11株及去除有机物菌10株.苦草根、叶际可培养微生物多样性较为丰富,该研究中筛选到的高效功能菌丰富了对苦草附生微生物资源的认识,为沉水植物合成菌群的研制和应用奠定基础.

马铃薯高代品系材料生长性状调查及抗旱性评价

为了筛选出用于实际生产与推广的优质高产品种,以24份马铃薯高代品系材料为研究对象,对其农艺性状、生理生化指标与产量性状进行调查测定,并对试验材料的叶绿素相对含量、叶片失水率、离体叶片电导率、株高和产量共5个指标进行相关性分析,利用隶属函数法对其抗旱性进行综合性评价。结果表明:早熟鲜食品系BF1111.8及中早熟加工品系BF113.31、BF113.13农艺性状优异;BF1111.8、BF1245.2和BF0750.43抗旱性极强;BF1111.8综合性状优异。

孕中晚期健康胎儿心脏二维斑点追踪成像参数与孕周的相关性

目的观察孕中晚期健康胎儿心脏二维斑点追踪成像(2D-STI)参数与孕周的相关性。方法前瞻性对279胎健康单胎胎儿行超声心动图检查,根据孕周将其分为A组(孕20~23^(+6)周,n=49)、B组(孕24~27^(+6)周,n=112)、C组(孕28~31^(+6)周,n=63)、D组(孕32~35^(+6)周,n=30)及E组(孕周≥36周,n=25);采用2D-STI获取胎儿左心室(LV)射血分数、LV和右心室(RV)面积变化率、LV和RV整体径向应变(GRS)、LV和RV心肌和心内膜整体纵向应变(MyoGLS,EndoGLS)、LV心肌和心内膜整体周向应变(MyoGCS,EndoGCS),比较组间差异,并分析与孕周的相关性。结果5组胎儿LV EndoGLS差异有统计学意义(P=0.044)。胎儿LV GRS及RV GRS与孕周均呈正相关(r=0.165、0.122,P均<0.05),而LV EndoGLS绝对值与孕周呈负相关(r=-0.133,P=0.026)。结论孕中晚期健康胎儿LV GRS及RV GRS与孕周均呈正相关,而LV EndoGLS绝对值与孕周呈负相关。

二维斑点追踪超声心动图技术对法布雷病患者右心室功能及应变特征的评估

目的:利用二维斑点追踪超声心动图技术评估法布雷病患者的右心室功能及应变特征。方法:回顾性收集2014年8月至2023年6月在北京大学第一医院经病理或基因检查证实的法布雷病患者57例(法布雷病组)和性别、年龄(±2岁)相匹配的健康对照者57例(正常对照组),比较两组临床基线资料、常规超声心动图参数及二维斑点追踪超声心动图技术测量的右心室应变参数。另将法布雷病组根据左心室质量指数(LVMI)大小分为左心室肥厚(LVH)亚组(n=22,男性LVMI≥115 g/m^(2),女性LVMI≥95 g/m^(2))和无LVH亚组(n=35,男性LVMI<115 g/m^(2),女性LVMI<95 g/m^(2)),比较两亚组的右心室应变特征,并分析右心室应变特征与LVH的关系。结果:(1)与正常对照组比,法布雷病组心率慢、B型利钠肽水平高、估算肾小球滤过率低,左心室后壁厚度(LVPWd)、室间隔厚度(IVSd)、右心室游离壁厚度(RVWT)增加,LVMI升高(P均<0.05)。(2)与无LVH亚组比,LVH亚组年龄大、收缩压高、估算肾小球滤过率低、B型利钠肽水平高,LVMI升高,RVWT增加(P均<0.05)。(3)与正常对照组比,法布雷病组的左心室整体长轴应变(LVGLS)、右心室整体长轴应变(RVGLS)、右心室游离壁应变(RVFWS)及右心室游离壁基底段应变(bal-RVFWS)、中间段应变(mid-RVFWS)和心尖部应变(api-RVFWS)均下降(P均<0.05)。右心室应变差值(ΔRV)在法布雷病组和正常对照组间的差异无统计学意义(P>0.05)。(4)与无LVH亚组比,LVH亚组的LVGLS、RVGLS均降低,ΔRV升高(P均<0.05),RVFWS、bal-RVFWS、mid-RVFWS和api-RVFWS在两亚组间的差异均无统计学意义(P均>0.05)。结论:法布雷病患者的右心室整体和节段应变均已受到损害,其中伴LVH的患者RVGLS减低而RVFWS相对保留。

多孔功能梯度压电纳米壳中波传播特性

基于非局部应变梯度理论,探究了含孔隙的功能梯度压电陶瓷纳米壳中波传播特性.利用Hamilton原理和一阶剪切理论推导了控制方程.结合非局部应变梯度理论和谐波解得到了尺度依赖的特征方程.数值讨论了尺度参数、波数、梯度指数、壳厚、孔隙率及电压对波传播特性的影响.研究表明:非局部参数和应变梯度参数对波传播频率的影响与波数密切相关,在一定范围内波数越大,尺度参数对频率的影响越大;另外,孔隙和梯度指数对频率具有耦合作用.