Multiplexed Energy Coupler for Rotating Equipment

A multiplexing antenna assembly can efficiently couple AC signal/energy into, or out of, rotating equipment. The unit only passes AC energy while blocking DC energy. Concentric tubes that are sliced into multiple pieces are assembled together so that, when a piece from an outer tube aligns well with an inner tube piece, efficient energy coupling is achieved through a capacitive scheme. With N outer pieces and M inner pieces, an effective N x M combination can be achieved in a multiplexed manner. The energy coupler is non-contact, which is useful if isolation from rotating and stationary parts is required. Additionally, the innovation can operate in high temperatures. Applications include rotating structure sensing, non-contact energy transmission, etc

Investigation of Stick Propellant Internal Perforation Erosive Burning on Interior Ballistics Performances

In this study, a thorough investigation of a stick propellant internal perforation erosive burning on interior ballistic performances is presented via extending the previous work of author. The stick propellant combustion process and the internal perforation erosive burning are revealed by numerical simulations. Different factors with respect to the stick propellant, including propellant length, internal perforation diameter and loading density are analysed in detail. Stick propellant length and the internal perforation diameter have a significant influence on the ballistic performance, the longer and smaller internal propellant have a greater erosive burning effect to the ballistic performance. Loading density has very weak influence on the ballistic

High-Temperature Surface-Acoustic-Wave Transducer

Aircraft-engine rotating equipment usually operates at high temperature and stress. Non-invasive inspection of microcracks in those components poses a challenge for the non-destructive evaluation community. A low-profile ultrasonic guided wave sensor can detect cracks in situ. The key feature of the sensor is that it should withstand high temperatures and excite strong surface wave energy to inspect surface/subsurface cracks. As far as the innovators know at the time of this reporting, there is no existing sensor that is mounted to the rotor disks for crack inspection; the most often used technology includes fluorescent penetrant inspection or eddy-current probes for disassembled part inspection. An efficient, high-temperature, low-profile surface acoustic wave transducer design has been identified and tested for nondestructive evaluation of structures or materials. The development is a Sol-Gel bismuth titanate-based surface-acoustic-wave (SAW) sensor that can generate efficient surface acoustic waves for crack inspection. The produced sensor is very thin (submillimeter), and can generate surface waves up to 540 C. Finite element analysis of the SAW transducer design was performed to predict the sensor behavior, and experimental studies confirmed the results. One major uniqueness of the Sol-Gel bismuth titanate SAW sensor is that it is easy to implement to structures of various shapes. With a spray coating process, the sensor can be applied to surfaces of large curvatures. Second, the sensor is very thin (as a coating) and has very minimal effect on airflow or rotating equipment imbalance. Third, it can withstand temperatures up to 530 C, which is very useful for engine applications where high temperature is an issue

Dual developmental mode: the top-down and bottom-up progress of language change in the Korean community of China since 1948

The language change resulting from outside contacts in the Yǒnbyǒn Korean language in China possesses distinctive characteristics. Unlike studies of language contact and change in most contexts, which often observe unidirectional contact-induced changes, the linguistic variation within the Chinese Korean community reveals a dual developmental mode. Ethnic Koreans in China have actively engaged with the Chinese language due to its sociopolitical dominance in China, resulting in significant top-down impacts on the Korean language. Conversely, the cognate Korean language has exerted an increasing influence on Yǒnbyǒn Korean speakers through a bottom-up mode. This research argues that the evolution of the Yǒnbyǒn Korean language possesses a distinctive characteristic: it can potentially be redirected and contested by social factors. Firstly, the sociopolitical landscape plays a pivotal role, exerting top-down influence stemming from modern standard Chinese. Secondly, sociocultural and economic factors, as experienced in the daily lives of ordinary Korean speakers, act as a bottom-up force, drawing influence from South Korean and English language. This research offers insights into the interplay of sociopolitical influences, sociocultural dynamics, economic forces, and individual preferences, by examining the dual developmental mode, driven by social contexts and mechanisms. The research sheds light on the contact-induced changes that affect the lexical, semantic, and structural dimensions of this minority language. The study has made methodological contributions by establishing a specialised corpus containing language data from Yǒnbyǒn Korean spanning the period between 1948 and 2020, filling a substantial gap in data related to this minority language in China that has been influenced by cross-border cognate languages. The research employs the Open-source Korean Text Processor, highlighting its appropriateness for studying the Korean language in the Chinese diaspora

Electric Field and SAR Reduction in High Impedance RF Arrays by Using High Permittivity Materials for 7T MR Imaging

Higher frequencies and shorter wavelengths present significant design issues at ultra-high fields, making multi-channel array setup a critical component for ultra-high field MR imaging. The requirement for multi-channel arrays, as well as ongoing efforts to increase the number of channels in an array, are always limited by the major issue known as inter-element coupling. This coupling affects the current and field distribution, noise correlation between channels, and frequency of array elements, lowering imaging quality and performance. To realize the full potential of UHF MRI, we must ensure that the coupling between array elements is kept to a minimum. High-impedance coils allow array systems to completely realize their potential by providing optimal isolation while requiring minimal design modifications. These minor design changes, which demand the use of low capacitance on the conventional loop to induce elevated impedance, result in a significant safety hazard that cannot be overlooked. High electric fields are formed across these low capacitance lumped elements, which may result in higher SAR values in the imaging subject, depositing more power and, ultimately, providing a greater risk of tissue heating-related injury to the human sample. We propose an innovative method of utilizing high-dielectric material to effectively reduce electric fields and SAR values in the imaging sample while preserving the B1 efficiency and inter-element decoupling between the array elements to address this important safety concern with minimal changes to the existing array design comprising high-impedance coils.Comment: 12 pages, 18 figures, 2 table

Multimodal surface coils for low-field MR imaging

Leveraging the potential of low-field Magnetic Resonance Imaging (MRI), our study introduces the multimodal surface RF coil, a design tailored to overcome the limitations of conventional coils in this context. The inherent challenges of low-field MRI, notably suboptimal signal-to-noise ratio (SNR) and the need for specialized RF coils, are effectively addressed by our novel design. The multimodal surface coil is characterized by a unique assembly of resonators, optimized for both B1 efficiency and low-frequency tuning capabilities, essential for low-field applications. This paper provides a thorough investigation of the conceptual framework, design intricacies, and bench test validation of the multimodal surface coil. Through detailed simulations and comparative analyses, we demonstrate its superior performance in terms of B1 field efficiency, outperforming conventional surface coils

Engineering the Surface/Interface Structures of Titanium Dioxide Micro and Nano Architectures towards Environmental and Electrochemical Applications

Titanium dioxide (TiO2) materials have been intensively studied in the past years because of many varied applications. This mini review article focuses on TiO2 micro and nano architectures with the prevalent crystal structures (anatase, rutile, brookite, and TiO2(B)), and summarizes the major advances in the surface and interface engineering and applications in environmental and electrochemical applications. We analyze the advantages of surface/interface engineered TiO2 micro and nano structures, and present the principles and growth mechanisms of TiO2 nanostructures via different strategies, with an emphasis on rational control of the surface and interface structures. We further discuss the applications of TiO2 micro and nano architectures in photocatalysis, lithium/sodium ion batteries, and Li–S batteries. Throughout the discussion, the relationship between the device performance and the surface/interface structures of TiO2 micro and nano structures will be highlighted. Then, we discuss the phase transitions of TiO2 nanostructures and possible strategies of improving the phase stability. The review concludes with a perspective on the current challenges and future research directions

RADAP: A Robust and Adaptive Defense Against Diverse Adversarial Patches on Face Recognition

Face recognition (FR) systems powered by deep learning have become widely used in various applications. However, they are vulnerable to adversarial attacks, especially those based on local adversarial patches that can be physically applied to real-world objects. In this paper, we propose RADAP, a robust and adaptive defense mechanism against diverse adversarial patches in both closed-set and open-set FR systems. RADAP employs innovative techniques, such as FCutout and F-patch, which use Fourier space sampling masks to improve the occlusion robustness of the FR model and the performance of the patch segmenter. Moreover, we introduce an edge-aware binary cross-entropy (EBCE) loss function to enhance the accuracy of patch detection. We also present the split and fill (SAF) strategy, which is designed to counter the vulnerability of the patch segmenter to complete white-box adaptive attacks. We conduct comprehensive experiments to validate the effectiveness of RADAP, which shows significant improvements in defense performance against various adversarial patches, while maintaining clean accuracy higher than that of the undefended Vanilla model

Dual-tuned Coaxial-transmission-line RF coils with Independent Tuning Capabilities for X-nuclear Metabolic MRS Imaging at Ultrahigh Magnetic Fields

Information on the metabolism of tissues in both healthy and diseased states has potential for detecting tumors, neurodegeneration diseases, diabetes, and many metabolic disorders in biomedical studies. Hyperpolarized carbon-13 magnetic resonance imaging (13C-HPMRI) and deuterium metabolic imaging (2H-DMI) are two emerging X-nuclei used as practical imaging tools to investigate tissue metabolism. However due to their low gyromagnetic ratios ($\gamma_{13C}$ = 10.7 MHz/T; $\gamma_{2H}$ = 6.5 MHz/T) and natural abundance, such method required the use of a sophisticated dual-tuned radio frequency (RF) coil where the X-nucleus signal is associated with the proton signal used for anatomical reference. Here, we report a dual-tuned coaxial transmission line (CTL) RF coil agile for metabolite information operating at 7T with independent tuning capability. Analysis based on full-wave simulation has demonstrated how both resonant frequencies can be individually controlled by simply varying the constituent of the design parameters. A broadband tuning range capability is obtained, covering most of the X-nucleus signal, especially the 13C and 2H spectra at 7T. Numerical results has demonstrated the effectiveness of the magnetic field produced by the proposed dual-tuned 1H/13C and 1H/2H CTLs RF coils. Furthermore, in order to validate the feasibility of the proposed design, both dual-tuned CTLs prototypes are designed and fabricated using a semi-flexible RG-405 .086" coaxial cable and bench test results (scattering parameters and magnetic field efficiency/distributions) are successfully obtained.Comment: 9 pages, 7 figure