实时三维超声心动图评价房间隔缺损的收缩形式及其影响因素

目的应用实时三维超声心动图(RT-3DE)技术评价继发孔型房间隔缺损(ASD)在心动周期中的收缩变化特征并探讨其可能的影响因素.方法对36例继发孔型ASD患者进行实时三维成像,3例患者因图像质量欠佳而剔除,在其余33例病例,结合三维数据工作站,分别测量缺损面积,缺损长轴及短轴上的最大及最小径,平行及垂直于三尖瓣水平的最大及最小径.计算上述测值的变化率,并将缺损面积的变化率与缺损最大径、年龄、心率、肺循环与体循环血流量之比(Qp/Qs)进行相关分析.结果缺损面积在心动周期的收缩变化显著,变化率从15.2%到76.9%,平均变化率为49.0%.缺损呈对称性收缩且与缺损最大径、心率、Qp/Qs无相关性,与年龄呈轻微负相关.结论RT-3DE可清晰显示ASD缺损的动态收缩变化特征,有助于理解心房水平分流的病理生理学改变.     

实时三维超声心动图在诊断心脏肿瘤中的应用价值

目的探讨实时三维超声心动图对心脏肿瘤的诊断价值.方法对7例心脏肿瘤患者进行二维、实时三维超声心动图检查,测量其左右径、上下径、及前后径,结果与手术或MRI对照.结果实时三维超声心动图可实时显示心脏肿瘤的空间位置、形态、大小以及与周围结构的关系.与手术或MRI结果的相比较,左右径r=0.99,SEE=2mm;上下径r=0.97,SEE=2.2mm;前后径r=0.98,SEE=2.1mm.二维超声测得的结果与手术或MRI结果相比较,左右径r=0.89,SEE=6mm;上下径r=0.91,SEE=4mm;前后径r=0.89,SEE=5mm.结论实时三维超声心动图操作简单、应用方便,可显示心脏肿瘤的整体形态,为心脏肿瘤患者的定性和定量诊断提供了可靠的新方法.     

实时三维彩色多普勒血流显像定量评估主动脉瓣反流的初步探讨

目的探讨实时三维彩色多普勒血流显像(RT3D CDFI)定量评估主动脉瓣反流的价值.方法应用实时三维超声心动图技术采集23例单纯性主动脉瓣反流患者的全容积数据库和三维彩色血流信号数据库,利用TomTec三维图像处理工作站分别测量左室舒张末期容积(LVEDV)、左室收缩末期容积(LVESV)和主动脉瓣彩色反流束容积(regurgitant jet volume,RJV),计算出反流束分数(RJF%).在二维超声心动图上用脉冲多普勒(PD-2D)测量计算反流容积(RV)和反流分数(RF%).对RT3D CDFI和PD-2D的测量值进行相关性分析.结果RT3D CDFI和PD-2D两种方法评价主动脉瓣反流的测值相关性良好,其中RT3D CDFI测得的RJV与PD-2D测得的RV相关性为r=0.93,Y=0.89X+3.9,SEE=8.6ml,P<0.001,二者间的均数差为-1.5ml,标准差为9.8ml;RT3D CDFI测得RJF%与PD-2D测得的RF%的相关性为r=0.88,Y=0.71X+14.8,SEE=6.4%,P<0.001,二者间的均数差为-1.2%,标准差为7.9%.结论RT3D CDFI可从三维空间对主动脉瓣反流进行评价,为临床定量评估主动脉反流提供了一种新方法.     

实时三维超声心动图评价风湿性二尖瓣狭窄瓣口面积的初步研究

为探讨实时三维超声心动图定量评价风湿性二尖瓣狭窄瓣口面积的可行性及准确性。分别应用二维法（2D法）、多普勒压力减半时间法（PHT法）及实时三维容积法（RT3DE法）检测42例风湿性二尖瓣狭窄患者二尖瓣瓣口面积（MVA）。结果除1例患者因二尖瓣瓣叶严重粘连钙化,未获得清晰的二尖瓣口三维图像外。其余41例风湿性二尖瓣狭窄患者均获得满意的二尖瓣瓣口实时三维图像：另外．RT3DE法与2D法及PHT法测量所得MVA差异无显著性意义（P〉0．05）．且相关性好（r分别为0．945、0．809）。可见实时三维超声心动图评价风湿性二尖瓣狭窄瓣口面积具有可行性和准确性．为临床风湿性二尖瓣狭窄瓣口面积的评价提供了一种新的测量方法。     

基于实时三维超声造影对于输卵管源性不孕症的诊断评价研究

目的:探讨实时三维子宫输卵管超声造影对于输卵管源性不孕症的诊断评价.方法:随机抽取在我院进行治疗的输卵管源性不孕症患者80名,按照统计学规则将抽取的样本分成对照组和研究组.对照组患者接受腹腔镜检查以及子宫输卵管碘油造影检查,研究组患者接受腹腔镜检查以及实时三维子宫输卵管超声造影检查,子宫输卵管碘油造影的结果接近金标准....     

联合检测二维超声心动图、BNP、6MWT、MMRC对慢性阻塞性肺疾病急性加重期患者右心功能不全的诊断意义

目的:探讨联合检测二维超声心动图、BNP、6MWT、MMRC对慢性阻塞性肺疾病急性加重期(AECOPD)患者右心功能不全的诊断意义.方法:纳入我院2019年7月-2020年7月收治的AECOPD患者共96例,其中AECOPD患者右心功能不全患者48例,设为研究组,48例为AECOPD患者,设为对照组,两组患者联合检测二...     

超声心动图在早期高血压性心脏病患者中的诊断价值分析

目的:研究超声心动图诊断早期高血压性心脏病的临床价值。方法:回顾性收集我院2020年1月-2020年12月收诊的早期高血压性心脏病患者80例的临床资料,并选取同期健康体检的志愿者80名,分别设为实验组、对照组。收集两组的超声心动图资料,对比两组的LVEF、LVEDD、ISV等超声心动图资料,并收集整理超声心动图对实验组患者的诊断准确率以及不同血压分级患者的超声心动图资料。结果:超声心动图诊断早期HHD的准确率为95.0%。实验组患者的LVEDD与对照组健康志愿者比较差异不明显,P>0.05;实验组的ISV、LVPW、LAD值均高于对照组健康志愿者,P<0.05;且实验组的LVEF和E/A比值明显低于对照组,P<0.05;在实验组患者中,随着血压分级的增加,ISV、LVPW、LAD值也随之提高,二者呈正相关关系,P<0.05;随着血压分级增加,LVEF水平和E/A比值随之下降,二者呈负相关关系,P<0.05;血压分级与LVEDD无明显关系,P>0.05。结论:超声心动图在早期高血压性心脏病患者的诊断中应用价值高,能早期检测出左室舒张功能受损、左房扩大等,利于临床医师早期诊断高血压性心脏病,同时指导临床治疗,值得推广。     

三维超声成像在诊断胎儿唇裂30例中的应用价值

目的：探究三维超声成像诊断胎儿唇裂的临床诊断效果及应用价值,为后期临床诊断提供参考。方法：选取我院门诊2009年1月-2012年1月期间收入行三维超声检测的3280例妊娠产妇的临床资料进行回顾性分析。结果：本组3280例孕妇中,经超声监测得到满意图像的3150例,超声显示单胎的为3056例,双胎36例,三胎5例,胎儿唇裂者30例,唇腭裂合并者23例。在联合诊断中,二维超声诊断时出现漏诊12例,三维0例;二维超声诊断误诊15例,三维0例。二维与三维检测结果在漏诊、误诊、准确率比较,差异具有统计学意义（P＜0.05）。结论：三维超声可为医务人员提供全面、直观、清晰且准确的诊断资料,具有临床价值,值得进一步推广及应用。     

Three-Dimensional Localization of Defects in Stay Cables Using Magnetic Flux Leakage Methods

The application of magnetic flux leakage (MFL) methods to the nondestructive evaluation (NDE) of metal parts has been known for several decades. The inspection of large-diameter cables (Ø 100 mm), such as bridge stay cables, is a new field of application for the MFL method. The large cross-section of the cables requires the generation of strong magnetic fields in order to obtain the induction fields necessary for an accurate inspection of the cables. A new device for the inspection of stay cables has been developed in order to meet the requirements given by the size of the cables. Measurements performed with the developed device on full-scale specimens in the laboratory and first calculations confirm the validity of the MFL approach to the inspection of bridge stay cables. The equipment was used satisfactorily in 2001 for the NDE inspection of the 68 locked coil stay cables (121 mm < Ø < 167 mm) of a bridge in Southeast Asia. For such cables, no exact localization within the cross section was performed. Thus far, an accurate indication of the position of the detected flaws along the length of the cables could be given. A qualitative statement about position and size of the flaws within the cross section of the cable could also be made. Given the large steel cross-section of the cables, no other nondestructive method to confirm the findings could be applied to assess the exact size and position of the detected flaws. The proposed analytical method presented in this paper makes it possible to increase the amount of information that can be extracted from the measured MFL data with regard to the exact location of the detected flaws within a cross section of a stay cable.     

Benchmark Solutions for Three-Dimensional Transient Heat Transfer in Two-Dimensional Environments Via the Time Fourier Transform

The evaluation of heat propagation in the time domain generated by transient heat sources placed in the presence of three-dimensional media requires the use of computationally demanding numerical schemes. The implementation of numerical 3D solutions may benefit from the existence of benchmark solutions to test the accuracy of approximate schemes.
With this purpose inmind, this article presents analyticalnumerical solutions to evaluate the heat-field elicited by monopole heat sources in the presence of three different inclusions, namely, a cylindrical circular solid inclusion, a cylindrical circular cavity with null fluxes and a cavity with null temperatures prescribed along its boundary, buried in an unbounded medium. The problem is first subjected to a time and space Fourier Transform, which allows the solution to be obtained in the frequency domain as summation of 2D solutions for different spatial wavenumbers. Then, using the inverse Fourier transforms in the wavenumber and frequency domains, the 3D time responses are synthesized. Complex frequencies are used to avoid the aliasing phenomena.
This methodology is first validated calculating the fundamental time solutions for one, two and three dimensions in an unbounded medium. Simulation analyses of these idealized models are then used to study the patterns of heat propagation in the vicinity of the inclusions.     

(TP-EDOT)2PF6 — Two-Dimensional Spin Array in a Three-Dimensional Lattice

The title complex was a Mott insulator, in which the head-to-head type dimer of newly synthesized donor molecule, 2-(thiapyran-4-ylidene)-4,5- ethylenedioxy-1,3-dithiole (TP-EDOT) accommodated a localized spin. Although the localized spins were arranged in three-dimensional (3D) framework, the interaction between them was interpreted as a twodimensional (2D) spin system. The ability of TP-EDOT to exhibit intermolecular interactions along the molecular longitudinal axis allowed to form a head-to-head dimer, which provided an elongated space to reserve a localized spin. The anisotropy of this dimer was regarded to be the origin of the novel 2D spin structure formed in the 3D lattice.     

Lamb波在铝板缝类缺陷检测中的应用

为了研究Lamb波在缺陷板检测中的应用,建立非线性Lamb波检测系统.该系统用于检测具有不同深度裂纹的铝合金板和具有不同拉伸载荷循环的铝合金板.通过快速傅里叶变换(FFT)对获取的时域波形进行分析,得到两种缺陷对Lamb波非线性效应的影响.测试结果表明,对于裂纹缺陷,缺陷深度增加将增大试件超声非线性效应.当裂纹深度超过...     

Three-Dimensional Solution and Experimental Confirmation for the Electric Resistivity Testing of Surface-Breaking Defects in Green-State Powder Metallurgy Compacts

This paper investigates electrostatic voltage distributions around a surface-breaking flaw due to an injected current of known strength. The direct 3-D solution of the voltage behavior over the flawed surface is obtained numerically by the use of a boundary integral formulation. A novel iteration method is applied to solve the resulting electrostatic integral equation for the unknown surface voltage distribution. In addition to investigating the sensitivity of different flaw sizes to the observed surface voltage distribution, important issues such as suitable probe spacing and current flow orientation are studied. For sufficiently small surface-breaking flaws, a simple image source model is developed to evaluate the voltage response of hairline cracks. The model is tested by comparing it with the developed numerical solution. Experiments aimed at establishing the validity of the modeling approach show remarkable agreement with the theoretical model.     

三维石墨烯的制备及其在超级电容器中的应用

目的 三维石墨烯在实际应用中所呈现的性能与其理论模拟结果相差甚远,目前尚无系统的原因分析和改进方法总结,回顾三维石墨烯的发展历程及近几年国内外研究进展是必要的,为三维石墨烯在工业设计和生产制备超级电容器电极活性材料中的应用提供参考.方法 综述三维石墨烯的制备方法,阐述其在超级电容器中应用的研究,针对三维结构塌陷问题的解决办法、杂原子掺杂提高材料整体比电容及石墨烯基电容器的理论模拟等方面进行总结.结果 三维石墨烯的制备方法主要有自组装法和模板法,自组装法还原度普遍较低,电容值一般为100～300 F/g;模板法制备的石墨烯比表面积可达500 m2/g以上;多元素掺杂体系在高电流密度下的电容保持率普遍不足80％;关于分级多孔结构的理论模拟研究不足.结论 制备分级多孔结构的三维石墨烯、多元素掺杂体系理论研究、非对称超级电容器的研究及应用将受到学者的关注.     

二维过渡金属碳氮化合物的生物医学应用

二维过渡金属碳化物、氮化物及碳氮化合物(MXenes)是一类新兴的二维纳米材料.由于其独特的光、电、磁、热等物理化学性能,MXenes二维材料被广泛应用到能源储备、环境监测、化学催化等领域.由于其大的比表面积、优异的近红外吸收和组分可调换等性质,近年来在生物医学方面也得到了快速的发展.简要介绍了MXenes二维纳米材料...