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作者：郭丞高雄医学大学

学位级别：硕士

研究目的：利用现有单位上的测量仪器，进行临床上放射治疗计画的剂量验证，并参考2005年E. Spezi利用多次位移的方式，以增加PTW 2d-array seven29的空间解析度，并实际带入不同部位的放射治疗计画，以比较此测量方式对不同部位之效果... 详细信息

研究目的：利用现有单位上的测量仪器，进行临床上放射治疗计画的剂量验证，并参考2005年E. Spezi利用多次位移的方式，以增加PTW 2d-array seven29的空间解析度，并实际带入不同部位的放射治疗计画，以比较此测量方式对不同部位之效果与不同位移次数下对于空间解系度的差异。材料与方法：放射治疗计画分别为头颈部与骨盆腔各10组，利用多次位移2d-array的测量位置以完整覆盖其二维平面，并且实际测量放射治疗计画的剂量分布。利用Matlab软体以加马指标(gamma index，GI)的方式比较测得的数据与放射治疗计画，探讨不同部位以多次位移2d-array的方式做测量之效果差异。结果：位移1次、2次、4次和8次的GI平均值分别为0.54、0.47、0.46和0.46，表示随着位移次数变多实际测量的剂量分布与放射治疗计画的差异变小，并透过成对样本t检定检查后具有统计学上的意义(p值＜0.05)。结论：因为2d-array的游离腔彼此间有间隔，本研究透过多次位移方式是证实可以有效增加空间解析度。但本研究的放射治疗计画与测量对象皆为2d-array和固态水假体，所以并无预想头颈部会因为具有许多窦腔(sinus)造成较多误差的情形发生，反而是头颈部在放射治疗计画中具有较多的小照野，经过多次位移后更能够将数据完整的收集。

关键词：强度调控放射治疗多次位移 2d array

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development of a 500 kHz pulse-echo acquisition system for three-dimensional ultrasound images of objects immersed in water 15

Development of a 500 kHz pulse-echo acquisition system for t...

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15th IEEE International Conference on Industry Applications, INdUSCON 2023

作者： Rodrigues, Estevão Patricio Buiochi, Flavio Departamento de Engenharia Mecatrônica e de Sistemas Mecânicos Universidade de São Paulo São Paulo Brazil

ISBN: (纸本)9798350314182

The development of an acquisition system that remotely captures echo signals to make three-dimensional ultrasound images of objects immersed in water is presented. The acquisition system is based on an STM32 microcontroller, which pulses a 500-kHz piezoceramic disc emitter, and so digitizes sixteen echo signals captured by two-dimensional array of sensors made of 1-3 piezocomposite. The digitized raw signals are transmitted to a personal computer (PC) via an Ethernet cable. The acquisition system was simplified by using the Power over Ethernet (PoE) technology, that integrates the power supply and data communication via the Ethernet cable itself. The beamforming is calculated on the PC, where the ultrasound images are displayed. Three-dimensional ultrasound images of objects immersed in water up to 1 meter away suggest that the proposed acquisition system can be improved for underwater purposes such as inspection of static underwater structures like bridges, pipeline occlusion and so on. ©2023 IEEE.

关键词： 2d array 3d Sonar Acquisition System Microcontroller Piezoelectric Ultrasound Ultrasound Imaging Underwater

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Taming vibrational resonance by transient high frequency

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PHYSICA d-NONLINEAR PHENOMENA 2024年 460卷

作者： Asir, M. Paul Chennai Inst Technol Chennai 60069 India

We investigate the phenomenon of vibrational resonance (VR) in a model of two -fluid plasma driven by biharmonic forcing. We introduce a transient high -frequency (HF) signal by implementing the control parameter z that clips the HF in rationale with the time period of the system. We found that one can efficiently tame the emergence and characteristics of VR with the introduction of z. We study a coupled 1d lattice and a 2d array of the model to decipher the influence of z on VR. We derive the analytical response curve of the uncoupled model at z = 1/2 and find good congruence with the numerical results. When z > 0 reduces the influence of the HF signal, we found that the diminution of z curtails the occurrence of VR. The study finds potential applications in the fields of engineering, physics, and biology where resonance due to vibration has to be damped.

关键词： Vibrational resonance 2d array Transient high frequency Biharmonic forcing

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Automatic estimation of surface and probe location for 3d imaging with bidimensional arrays

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NdT & E INTERNATIONAL 2024年 141卷

作者： Cosarinsky, Guillermo Cruza, Jorge F. Munoz, Mario Camacho, Jorge CSIC Inst Phys & Informat Technol ITEFI Ultrasound Syst & Technol Grp GSTU C Serrano 144 Madrid 28006 Spain Natl Atom Energy Commiss CNEA Non Destruct Testing Dept Ave Gral Paz 1499B1650 Buenos Aires Argentina Univ Alcala Henares Escuela Politecn Elect Dept Ctra Madrid BarcelonaKm 33600 Madrid 28805 Spain

Ultrasound imaging for Non destructive Testing is frequently performed in an immersion setup, where water is used as coupling medium between the probe and the component under test. For the computation of the time delays needed for beam-forming, the shape of the component surface and probe location and orientation (PLO) must be known. In this work we develop methods for the automatic detection of the surface and the estimation of PLO for 2d array probes. In particular, the methods developed apply to three types of elementary surfaces which are usually found in industrial and structural components: planes, cylinders and spheres. The methods use the measured surface echoes Time of Flight (TOF) to fit parametric models based on ray propagation and reflection on the surface, giving the coordinates and Euler angles that define the PLO relative to the component under test. Validation experiments with four test specimens representing the three types of surfaces are presented . The accuracy and precision of estimated PLO coordinates and angles are analyzed, and a Total Focusing Method (TFM) imaging example is shown achieving a correct detection of artificial defects in the component for a different PLOs.

关键词： Ultrasound imaging 3d imaging 2d array Matrix array Surface detection Refraction

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Oriented Growth of Parallel-Standing Bimetallic Nanosheet arrays for Enhanced Charge Transfer

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AdVANCEd FUNCTIONAL MATERIALS 2024年第36期34卷

作者： Zhou, Yu Hu, Yiping Lu, Shaojie Wang, dong Ma, dongsheng Gong, Xueqing Yue, Qin Univ Elect Sci & Technol China Inst Fundamental & Frontier Sci Chengdu 610054 Peoples R China East China Univ Sci & Technol Ctr Computat Chem Sch Chem & Mol Engn State Key Lab Green Chem Engn & Ind Catalysis 130 Meilong Rd Shanghai 200237 Peoples R China East China Univ Sci & Technol Res Inst Ind Catalysis Sch Chem & Mol Engn 130 Meilong Rd Shanghai 200237 Peoples R China

Fabricating highly oriented 2d nanosheet arrays is crucial for boosting their performance in electronics, catalysis, optics, and energy conversion, while it remains a challenge due to the high surface energy often leads to random aggregation or interlaced structure. In this study, it is found that the exposed facet of Fe2O3 can greatly influence the interface growth arrangement of bimetallic hydroxide (NiCo(OH)2) nanosheets. The NiCo(OH)2 nanosheets tend to parallel-standing on the cubic and spindle Fe2O3 while random- and interlaced-standing on the Fe2O3 hexagonal nanoplates and microspheres. The theoretical simulation further indicates the orientation of deposited hydroxide sheets is decided explicitly by the interfacial lattice match/mismatch. Compared to the common interlaced structure of nanosheets, the parallel-standing nanosheet arrays reduce grain boundaries and improve the charge transfer efficiency. As a result, the derived NiCoP cages exhibit a promising oxygen evolution reaction performance with an overpotential of 255 mV at 10 mA cm-2, and the maximum current density of 400 mA cm-2 with the overpotential of 319 mV. The parallel-standing of NiCo(OH)2 nanosheets on Fe2O3 induced by crystal lattice-matching principle with reduced grain boundaries can enhance the electron transfer and improve the electrochemical catalytic performance. image

关键词： 2d array charge transfer interface co-assembly lattice matching oriented growth

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Boundary array Transducer and Beamforming for Low-Cost Real-time 3d Imaging

Boundary Array Transducer and Beamforming for Low-Cost Real-...

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IEEE International Ultrasonics Symposium (IEEE IUS)

作者： Yen, Jesse T. Powis, Emily Univ Southern Calif Biomed Engn Los Angeles CA 90007 USA

ISBN: (纸本)9781728154480

Recent studies suggest that ultrasound can be used for serial monitoring to guide therapeutic interventions at the point of care. A low-cost 3-d imaging may be well suited for this application due to greater accuracy and reproducibility over 2-d imaging. Previous work on arrays and systems for 3d imaging have focused on either 2d array transducers, hardware, or software alone. In this work, a systems-based "ground up" approach to develop real-time 3d (RT3d) ultrasound is investigated and compared to a full-sampled array. A 3 MHz, 64 x 64 rectangular boundary array was simulated in Field II and compared to a fully-sampled array. To improve depth of penetration, coded excitation is used. due to the sparseness of the RBA, novel apodization techniques are applied to suppress sidelobes and clutter.

关键词： 2d array 3d ultrasound sparse fully-sampled beamforming clutter suppression apodization sidelobes

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Ultrasonic imaging of 3d displacement vectors using a simulated 2d array and beamsteering

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ULTRASONICS 2013年第2期53卷 615-621页

作者： Housden, R. James Gee, Andrew H. Treece, Graham M. Prager, Richard W. Univ Cambridge Dept Engn Cambridge CB2 1PZ England

Most quasi-static ultrasound elastography methods image only the axial strain, derived from displacements measured in the direction of ultrasound propagation. In other directions, the beam lacks high resolution phase information and displacement estimation is therefore less precise. However, these estimates can be improved by steering the ultrasound beam through multiple angles and combining displacements measured along the different beam directions. Previously, beamsteering has only considered the 2d case to improve the lateral displacement estimates. In this paper, we extend this to 3d using a simulated 2d array to steer both laterally and elevationally in order to estimate the full 3d displacement vector over a volume. The method is tested on simulated and phantom data using a simulated 6-10 MHz array, and the precision of displacement estimation is measured with and without beamsteering. In simulations, we found a statistically significant improvement in the precision of lateral and elevational displacement estimates: lateral precision 35.69 mu m unsteered, 3.70 mu m steered;elevational precision 38.67 mu m unsteered, 3.64 mu m steered. Similar results were found in the phantom data: lateral precision 26.51 mu m unsteered, 5.78 mu m steered;elevational precision 28.92 mu m unsteered, 11.87 mu m steered. We conclude that volumetric 3d beamsteering improves the precision of lateral and elevational displacement estimates. (C) 2012 Elsevier B.V. All rights reserved.

关键词： Elastography Strain imaging 3d displacement estimation Beamsteering 2d array

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Quick SAR measurement system by 2d array E-field sensors

Quick SAR measurement system by 2D array E-field sensors

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3rd Asia-Pacific Microwave Conference Proceedings (APMC)

作者： Gimm, Yoon-myoung Ju, Youngjun Kahng, Sungtek Lee, Yuri Lee, Seungbae Dankook Univ Sch Elect & Elect Engn Room 4092nd Eng Bldg152 Jukjeon Ro Yongin 448701 Gyeonggi Do South Korea EMF Safety Inc Yongin 448701 Gyeonggi Do South Korea Incheon Natl Univ Dept Informat & Telecommun Incheon 406772 South Korea

ISBN: (纸本)9781479914722

The safety on human body against electromagnetic fields radiating from mobile devices has been investigated for a long time. The measurement method of RF power absorption to human body from wireless devices usually adopted robot scanning in the phantom in the past. But it takes a very long time to evaluate the SAR value of a mobile device. In this paper, a quick SAR measurement system using a 2d array of E-field probes having 3 axes isotropic characteristics is proposed. It is possible to fast estimate the volume SAR by a software with the 2d surface SAR data acquired by arrayed probes deleting robot moving time.

关键词： quick SAR E-field probe radio frequency 2d array human safety

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Ultrasound Transmitter for Non-invasive Vagus Nerve Stimulation

Ultrasound Transmitter for Non-invasive Vagus Nerve Stimulat...

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作者： Yang, Xinyu Delft University of Technology

学位级别：硕士

The main objective of this thesis is to design a transmitter channel which is implemented in a 2d phased-array ultrasound neuromodulation system aiming for the vagus nerve stimulation. The vagus nerve has the widest distribution in the parasympathetic system and it oversees several important bodily functions such as the control of mood, immune response, digestion, and heart rate. The potential of vagus nerve neuromodulation in the medical area is huge with these functions and has been studied for decades. The traditional way of vagus nerve stimulation (VNS) is electrical stimulation which requires surgery to implant the stimulator under the skin. It has been proven that electrical VNS has therapeutic effects on many diseases such as rheumatoid arthritis, refractory epilepsy and depression. However, there are still several limitations to electrical VNS. Inside the vagus nerve, there are several fibers and some unwanted fibers will be stimulated because the spatial resolution of electrical VNS is relatively low. Side-effects including cough, throat pain, voice alteration, and dyspnea are caused due to inadequate spatial resolution. Compared with the electrical approach, focused ultrasound wave could provide a high spatial resolution and does not require any surgery. It has been proven that the ultrasound stimulation could modulate the neuron activity and applications have been conducted in the stimulation for the central and peripheral nervous system, including the vagus nerve. Using a 2-d phased array, the ultrasound VNS system could also tune its focal spot in a 3d space without any mechanical controlling stage, which enables the VNS device to be portable while remaining its precision. The detailed modulation mechanism of the VNS is still under discovery and the ultrasound VNS devices are of great potential with the advantages mentioned above. In an ultrasound VNS system, the transmitter is an essential section which determines the accuracy of spatial resolution and

关键词： vagus nerve neuromodulation ultrasound transmitter 2d array

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High-Power VCSEL arrays with Customized Beam divergence for 3d Sensing Applications 23

High-Power VCSEL Arrays with Customized Beam Divergence for ...

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Conference on Vertical-Cavity Surface-Emitting Lasers XXIII

作者： Okur, Serdal Scheller, Maik Seurin, Jean-Francois Miglo, Alexander Xu, Guoyang Guo, dingkai Van Leeuwen, Robert Guo, Baiming Othman, Hasan Watkins, Laury Ghosh, Chuni Ams AG 1 Elect Dr Mercerville NJ 08619 USA

ISBN: (数字)9781510625198

ISBN: (纸本)9781510625198

The demand for highpower verticalcavity surfaceemitting laser (VCSEL) arrays is increasing continuously due to the growing market for 3d sensing solutions. In these applications (e.g. face recognition or driveassistance systems), the distances of the objects of interest vary by orders of magnitude. For this reason, a flexible tailoring of the beam divergence is desired. In this work, we discuss methods to tune the emitted beam profile by only optimizing the epitaxial structure of a VCSEL. We show results of VCSEL arrays with beam divergences ranging between similar to 10 degrees and 45 degrees. This technique is also power scalable and multi-watt VCSEL arrays can be realized.

关键词： Semiconductor lasers vertical-cavity surface-emitting lasers (VCSELs) high efficiency high-power 2d array beam divergence brightness

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