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[IEEE 2017 IEEE International Symposium on Medical Measurements and Applications (MeMeA) - Rochester, MN, USA (2017.5.7-2017.5.10)] 2017 IEEE International Symposium on Medical Measurements and Applications (MeMeA) - The calibration of targeting errors for an ultrasound-guided high-intensity focused ultrasound system
摘要： Accurate targeting is one indispensable feature of image-guided high-intensity focused ultrasound (HIFU) systems for treatment safety and efficacy. In our previously developed ultrasound-guided phased-array HIFU system, a rotatable imaging probe was mounted into the central hole of applicator for targeting and monitoring. Two-dimensional image sequence of different imaging planes can be obtained by rotation of the probe. The misalignment between the spots predetermined in the image and the spots sonicated in the tissue can result in the ablation of normal tissue outside the targeting volume, and thus targeting error is unavoidable. An acrylic plate internally placing two flat-head bolts was constructed to measure and calibrate the targeting error. The imaging planes were switched from ?90° to 90° with a 30° step, and the targeting errors were measured 12 times for each of these planes before and after calibration. The targeting errors in other imaging planes could be estimated by linear interpolation using the measured errors in the nearest two imaging planes. The coordinates of the spots to be sonicated were corrected in consideration of the targeting errors in the selected imaging plane. After calibration, the mean targeting errors were reduced to 0.30~0.68 mm from 0.86~1.74 mm. Besides, in the ex vivo experiment the needle-thermocouple tip was used as the target which could be identified in the image. The temperature rise measured by the thermocouple during sonication was in accordance with the theoretical result. In conclusion, the calibration of targeting errors is effective for our system, and the targeting accuracy is also capable to ensure safe sonication.
关键词： Phased-array,Ultrasound-guided high-intensity focused ultrasound (USgHIFU),Targeting accuracy,Calibration
更新于2025-09-04 15:30:14
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Imaging With 3-D Aperture Synthesis Radiometers
摘要： The spatial resolution is still a problem in passive microwave remote sensing, especially in low frequency. In recent years, the satellite formation flying has been proposed. Based on this technique, a large array is able to be synthesized in orbit to achieve higher spatial resolution. However, it is a big challenge for the control system to constrain all the satellites in a coplane in orbit. The 3-D array configuration is a good choice for a synthesized array based on satellite formation flying. In this paper, the complete formulation of visibility functions, including system imperfections, in a 3-D aperture synthesis radiometer (3-D ASR) is derived. The array factor of a 3-D ASR is defined. The reconstructed modified brightness temperature (BT) is a 3-D linear convolution of the modified BT and the array factor. Based on this relationship, the reconstruction method for a practical 3-D ASR is studied. The numerical results demonstrate that the reconstruction method is correct and stable. Finally, a discussion is given to analyze several existing methods that were proposed to reconstruct BT image for 3-D arrays in radio astronomy and earth observation. Compared with these existing methods, our imaging method is more suitable for earth observation based on the technique of satellites formation flying in low earth orbit. In addition, according to the derivations, some mature techniques that were developed for 2-D ASRs may be applied to 3-D ASRs.
关键词： visibility functions,image reconstruction,array factor,3-D aperture synthesis radiometers (3-D ASRs),modified brightness temperature (BT)
更新于2025-09-04 15:30:14
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Optimization of CdS/TiO2 Nanotube-Array Composite Photocatalysts Prepared by Electrodeposition
摘要： Titania nanotube arrays were prepared by titanium anodizing, then CdS/TiO2 nanotube arrays composite photocatalysts were prepared by an AC electrodeposition method for different times. The morphology and crystal structure of the CdS/TiO2 composite photocatalysts were characterized by SEM and XRD. The photoelectrochemical properties of the composites were investigated by means of UV-visible absorption spectra and photocurrent measurements. The photocatalytic activity was evaluated by the degradation of methyl orange under UV-visible light irradiation. The results show that there is an optimum deposited time for the highest photocatalytical activity of the CdS/TiO2 composite photocatalysts under UV-visible light irradiation and the optimum deposited time is determined to 3 min.
关键词： Electrodeposition,Nanotube array,Composite photocatalyst,Methyl orange,CdS/TiO2
更新于2025-09-04 15:30:14
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[IEEE 2018 1st International Cognitive Cities Conference (IC3) - Okinawa, Japan (2018.8.7-2018.8.9)] 2018 1st International Cognitive Cities Conference (IC3) - A Novel Image Analysis of Light Emitting Diode Array Biostimulation Applied on Microcirculation
摘要： A novel development platform of the specific microcirculation analysis was proposed in this study. This study was to observe the effect of the blood microcirculation with LED stimulation. The experiment involved the light emitting diode array (LEDA), the designed control board and the image processing algorithm on the platform. LEDA (six LEDs, wavelength 660 nm, operating frequency 8 - 15 Hz) was used to stimulate the palm of the subject, and then, the microcirculation images were analyzed by the image processing algorithm. The blood velocity on the ring finger was increased after LEDA stimulation, and it was approximately 1.7 times compared with and without the light stimulation. Thus, LEDA stimulation on the palm enhanced the microcirculation. Also, a specific platform of LEDA system with microcirculation measurement was developed in this study.
关键词： image processing algorithm,microcirculation,light emitting diode array
更新于2025-09-04 15:30:14
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Multi-Color Coherent Smith-Purcell Radiation with Controllable Direction from 2D Rectangular Sub-Wavelength Hole Array
摘要： We proposed a multi-color Smith-Purcell radiation source with controllable emission direction by using a sheet free-electron beam to drive the two-dimensional rectangular sub-wavelength hole array. Each hole is an electromagnetic wave oscillating and radiating unit with specified frequencies. The coherent radiation is generated when the radiation from all units constructively interfere. By adjusting the arrangement of the sub-wavelength hole array, the coherent radiation direction could be steered in the three dimensional space.
关键词： terahertz source,sub-wavelength hole array,free-electron beam,Smith-Purcell radiation,coherent radiation
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE International Students' Conference on Electrical, Electronics and Computer Science (SCEECS) - Bhopal, India (2018.2.24-2018.2.25)] 2018 IEEE International Students' Conference on Electrical, Electronics and Computer Science (SCEECS) - Improving the output power of Solar PV Array under different irradiation conditions
摘要： The factors that influence the output power of Solar Photo-Voltaic (SPV) Array are temperature of the Photo Voltaic cell, solar insolation and shading pattern. Partial shading is the main disadvantage that occurs while reducing the output power of the SPV Energy. To counter this disadvantage, a new reconfiguration technique Tom-Tom configuration is used to reconfigure the Solar Photo-Voltaic (SPV) Array to enhance the output power under partial shaded conditions. The theoretical and MATLAB/Simulink results give the ‘PV’ characteristics for the conventional and proposed techniques. From the results, it can be inferred that more output power is provided by Tom-Tom configuration than the conventional Total Cross Tied (TCT) pattern and the multiple peaks are minimized. Shade dispersion concept is presented by Tom-Tom, using which the concentrated shaded is diluted. The various shading patterns those are available in the literature are used to verify the performance of the proposed system. Results reaffirm that the output power is increased if the shaded panels are relocated.
关键词： Partial Shading,Solar PV Array,Tom-Tom Configuration
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE International Workshop on Electromagnetics: Applications and Student Innovation Competition (iWEM) - Nagoya, Japan (2018.8.29-2018.8.31)] 2018 IEEE International Workshop on Electromagnetics:Applications and Student Innovation Competition (iWEM) - Design for Bandwidth Enhancement of Traveling-Wave Microstrip Array Fed from Both Ends
摘要： A microstrip antenna has been applied to various millimeter-wave technologies. A traveling-wave microstrip antenna suffers from the narrow bandwidth of the termination element. We propose the way to extend the bandwidth by feeding from both ends of the microstrip antenna. By feeding from two ports, we can design an antenna without termination element. Furthermore, the change of aperture distribution due to frequency shift will be canceled out by the input from another port. Its performance in millimeter-wave band is evaluated by simulation in this paper.
关键词： microstrip antenna,millimeter-wave,array antenna
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - A Circularly Polarized Metasurface Antenna
摘要： The concept of metasurface antennas based on electrically small resonators was recently introduced and has opened a new window into the design of high gain antennas. In the earlier work, a linearly polarized metasurface antenna was designed and fabricated. In this work, we present the design of a circularly polarized metasurface antenna. An array of 8 × 8 cross-shaped resonators was designed to operate at 3 GHz with an overall array size of 12 cm × 12 cm (1.2 (cid:540) × 12 (cid:540)). By feeding the resonators with appropriate phases, we achieved circular polarization with a high gain of approximately 12 dBi.
关键词： feed network,Antenna array,circular polarization,metasurface
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - A Novel Electronically Wideband Steering System using Rotman Lens for 5G Applications at 28 GHz
摘要： this paper presents the design, simulation and measurement results for a beam steerable system, which covers the frequency range from 22 GHz to 35 GHz for 5G applications. A Rotman Lens with five input ports and six output ports is the beamforming network that is connected to a six circular patch L-shaped reflector antennas. This novel system covers a wide scanning angle from -45 to +45 degree for all frequencies. In addition, the simulated and measured results show that the Rotman Lens fed-antenna array has the S11 response less than 10dB in the frequency range of 22 to 35 GHz.
关键词： Beamforming,steering system,Rotman Lens,5G,array antenna
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - A Compact Vivaldi Antenna Array for 5G Channel Sounding Applications
摘要： A compact design of phased array Vivaldi antenna for channel sounding applications is proposed. 64-elements of low-profile 22 GHz Vivaldi antennas with coaxial-to-SIW feeds and well-defined end-fire radiation patterns have been used to form an 8×8 planar array design. The antenna elements are designed on 1.6 mm Arlon AD-320 substrates ((cid:304)=3.2 and (cid:303)=0.0038). The structure of SIW is composed of two rows of cylinders between metal plates improve the radiation performance of the which can elements. The proposed phased array antenna has a compact size with frequency response of 21-23 GHz. It has good features in terms of impedance-matching, gain and efficiency characteristics. More than 22 dB realized gain, 23 dBi directivity, and -0.5 dB (90%) total efficiency have been obtained. In addition, the performance of the planar array with different numbers of the radiators has been investigated.
关键词： 5G,channel sounding,phased array design,Vivaldi antenna
更新于2025-09-04 15:30:14