Results 41 to 50 of about 7,695 (169)
Research on MFL Testing in Tank Plates Based on AC-DC Composite Magnetization [PDF]
, 2014 目前，对于储罐、管道等铁磁性材料的安全检测，最常用的技术就是无损检测技术。其中，漏磁检测技术凭借探头结构简单、无需耦合剂、检测灵敏度高等优点，在储罐、管道的无损检测领域受到广泛的应用。 本文首先研究了漏磁检测技术的发展现状，并分析了现有技术的特点及其不足，在现有检测技术基础上提出了一种基于交直流复合磁化的储罐钢板漏磁检测技术。该方法利用交流磁化深度浅和直流磁化深度深的特点，对漏磁信号进行分离处理，利用直流漏磁信号发现缺陷，而交流漏磁信号则用于内外表面缺陷识别；其次，介绍了复合磁化检测技术的基本原理 ...
张忠远
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Ultrasound in Obstetrics &Gynecology, Volume 65, Issue 1, Page 114-121, January 2025.ABSTRACT Objective Adhesions between the uterus, bladder and anterior abdominal wall are associated with clinical sequelae, including chronic pelvic pain and dyspareunia, and can also yield complications during surgery. The transvaginal sonographic (TVS) sliding bladder sign is a minimally invasive diagnostic tool to evaluate the presence of ...
N. Min +9 more
wiley +1 more source
, 2001 平面活塞型超声换能器是长期来在超声检测以及其他超声应用技术中广泛采用的一种换能器类型。由于制作工艺简单，结构坚固，且又利用压电陶瓷的纵向机电耦合系数，因此具有良好的电声性能。然而，这种类型的换能器在媒质中产生的辐射声场，有其“先天性”的不足之处，在近场中无论平面活塞的频率和半径如何变化，轴上和沿径向上都呈现出极大和极小交替分布的干涉现象，因此我们有必要继续寻求更为理想的辐射形式。 本文分别设计和讨论了二种辐射形式的超声换能器:束控换能器和高斯换能器。在理论上讨论了这二种换能器的辐射声场分布、结构特点 ...
陈天润
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Routine 36‐week scan: prediction of small‐for‐gestational‐age neonate
Ultrasound in Obstetrics &Gynecology, Volume 65, Issue 1, Page 20-29, January 2025.ABSTRACT Objectives First, to compare the predictive performance of routine ultrasonographic estimated fetal weight (EFW) at 31 + 0 to 33 + 6 and 35 + 0 to 36 + 6 weeks' gestation for delivery of a small‐for‐gestational‐age (SGA) neonate. Second, to compare the predictive performance of EFW at 36 weeks' gestation for SGA vs fetal growth restriction ...
S. Adjahou +5 more
wiley +1 more source
Development of Nondestructive Testing Probe Based on Magnetoacoustic Tomography with Magnetic Induction [PDF]
, 2014 铝合金板材具有密度小、强度高、耐腐蚀等特点，在生产生活中被得到广泛应用。但其表面及其亚表面的损伤具有很强的隐蔽性和危险性，由此导致的交通事故、生产事故以及管线泄漏事故等严重威胁着人民群众的生命财产安全以及我们赖以生存的生态环境。目前业界针对裂纹检测主要采用涡流检测技术，针对腐蚀检测主要采用红外成像技术。 本文提出了一种新的方法，将医学检测手段中的感应式磁声成像技术（MagnetoacousticTomographywithMagneticInduction,MAT-MI）引入金属材料的无损检测技术中 ...
夏晓昊
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Orthogonal differential eddy current testing for internal detection of oil and gas pipeline based on incremental permeability extraction [PDF]
Objective Serving as the primary mode of transporting oil and natural gas, pipelines are prone to corrosion, cracks, and other defects under intricate operational conditions.
Bingfeng YU +7 more
core +1 more source
Ultrasound in Obstetrics &Gynecology, Volume 64, Issue 6, Page 808-817, December 2024.ABSTRACT Objectives The primary aim was to validate the International Ovarian Tumor Analysis (IOTA) benign simple descriptors (BDs) followed by the Assessment of Different NEoplasias in the adneXa (ADNEX) model, if BDs cannot be applied, in a two‐step strategy to classify adnexal masses identified during pregnancy. The secondary aim was to describe the
J. Barcroft +8 more
wiley +1 more source
Gaoya dianqi, 2018 超声波局部放电检测法是检测气体绝缘组合电器（GIS）绝缘状况的重要手段。对GIS进行超声波法局部放电检测时,现场会遇到机械振动、外部电晕干扰和磁致噪声这三种典型的干扰,这三种干扰与放电特征图谱相似,极易对检测人员造成误判。结合现场实测经验,分析了三种典型干扰的信号特征,提出了现场干扰的判别及排除方法。文中提出的干扰辨别及排除方法在现场超声波局放带电检测中取得了良好的效果。
冯新岩 +3 more
doaj
Research of Multi-domain Eddy Current Testing Simulation [PDF]
, 2012 飞行器维修中使用无损检测可以及早发现缺陷，保证飞行器的质量并维持其持续适航。其中涡流检测在导体表面和近表面缺陷检测中具有的灵敏度高，使用方便和非接触、单面检测的优势，因而成为飞行器无损检测的重要手段之一。 涡流检测中，需要对探头的激励频率、提离等参数进行优化。进行涡流计算仿真，可以低成本的研究这类问题。有限元法在涡流计算中得到了广泛的应用。但是随着仿真模型的复杂化以及模型中含有物体运动时，传统的仅用一个求解区域的有限元法在对该类问题的处理上遇到了瓶颈 ...
何荣光
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Nonlinear guided wave evaluation method for detecting incipient performance degradation in polyethylene plate/shell structure [PDF]
ObjectiveQuantitative characterization of the extent of incipient damage in polyethylene plate/shell structures is crucial for ensuring the safe operation and preventive maintenance of oil and gas facilities.
Gang LIU +6 more
core +1 more source