Review
Polymer Science
Rhonira Latif, Mimiwaty Mohd Noor, Jumril Yunas, Azrul Azlan Hamzah
Summary: This paper reviews the use of mechanical energy harvesters and microphone sensors in totally implanted hearing systems, highlighting the advantages and potential of polymer-based piezoelectric transducers.
Article
Audiology & Speech-Language Pathology
Maartje M. E. Hendrikse, Theda Eichler, Volker Hohmann, Giso Grimm
Summary: This study investigates the influence of hearing impairment on self-motion and the interaction of hearing aids with self-motion. The findings show that participants with hearing impairment primarily use head movements rather than eye movements for self-motion, and the use of an adaptive differential microphone (ADM) does not significantly impact participants' self-motion behavior.
Article
Engineering, Electrical & Electronic
Ilseon Yoo, Hyunsoo Kim, Sanghyeok Yang, Donggu Kim, Dae-Sung Kwon, Janghyeon Lee, Taeho Jeong
Summary: This article presents a unidirectional microelectromechanical system (MEMS) microphone single module designed for handsfree and voice recognition systems in automobiles. To address the impact of in-cabin noise and temperature variation on system performance, noise suppression and improvement of signal-to-noise ratio (SNR) are necessary for the microphone. The study achieves a capacitive MEMS microphone module with a high SNR and unidirectional characteristic by designing the structure, package, and module. Using a slit-edged membrane and a porous SU-8 filter, the microphone achieves improved sensitivity, SNR, and suppression of noise signals from undesired directions.
IEEE SENSORS JOURNAL
(2022)
Article
Nanoscience & Nanotechnology
Ashiqur Rahaman, Byungki Kim
Summary: This paper investigates three-dimensional sound source localization using a mm-sized array of piezoelectric MEMS directional microphones inspired by the ears of the fly Ormia ochracea, achieving a high level of accuracy in experimental measurements.
MICROSYSTEMS & NANOENGINEERING
(2022)
Article
Engineering, Electrical & Electronic
Ashiqur Rahamanand, Byungki Kim
Summary: This article presents an analytical and experimental work on sound source localization (SSL) in 2D using a pair of fly O. ochracea inspired MEMS directional microphones. By utilizing a 90 degrees phase difference between the X-axis and Y-axis, the study achieved accurate SSL in the X-Y plane.
IEEE SENSORS JOURNAL
(2021)
Article
Acoustics
Yong Chen, Ming Wu, Ling Lu, Xing Fang, Jun Yang
Summary: A microphone array is utilized to enhance the target signal and suppress non-target interference when measuring the SPL of a target noise source in an outdoor environment. A real-time calibration method is introduced to compensate for the SPL difference caused by the mismatch in a MEMS microphone array. The method has been experimentally verified and shown to provide accurate and robust SPL calibration.
Article
Acoustics
T. Wenzel, R. Rettig
Summary: This paper discusses the development of a protective 3D-printed membrane for outdoor applications, which effectively protects MEMS-based microphones. The acoustic characteristics of the membrane are analyzed, simulated, and experimentally validated. The flexible material structure of 3D-printed membranes allows for long-term outdoor protection with minimal impact on acoustic performance.
Article
Physics, Applied
Dipeng Ren, Zhi-Mei Qi
Summary: This study developed a miniature biomimetic microphone with good signal demodulation capability and wide sound source localization range. The biomimetic microphone shows many advantages in signal demodulation and proposes a new sound source localization method to effectively extend the localization range.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Ashiqur Rahaman, Haeil Jung, Byungki Kim
Summary: This study focuses on a new formation of the D33 mode, the coupled D33 mode, based on piezoelectric sensing to improve the acoustic functionalities of bio-inspired piezoelectric MEMS directional microphone. Simulation using COMSOL Multiphysics software and experimental validation with a piezoelectric MEMS directional microphone inspired by the ears of the fly Ormia ochracea show substantial improvement in performance compared to the regular D33 mode, indicating the novelty of this work.
APPLIED SCIENCES-BASEL
(2021)
Article
Audiology & Speech-Language Pathology
Zoran Djinovic, Robert Pavelka, Milos Tomic, Georg Sprinzl, Julia Gertrud Mueller, Hannes Traxler
Summary: This paper presents an experimental study on a novel fiber optical vibrometer for use as a totally implantable fiber-optic microphone for hearing aids. The results show that the implanted system accurately measures the amplitude of incus vibrations at different sound pressure levels and frequencies.
Article
Engineering, Electrical & Electronic
Tzu-huan Peng, Jin H. Huang
Summary: This study developed a lumped-parameter model based on the boundary element method for simulation and analysis of directional microphones. By comparing with experimental data, the accuracy and applicability of the model were validated, providing in-depth research on the acoustic characteristics of microphones.
SENSORS AND ACTUATORS A-PHYSICAL
(2021)
Article
Neurosciences
Jing Chen, Zhe Wang, Ruijuan Dong, Xinxing Fu, Yuan Wang, Shuo Wang
Summary: The study found that the use of wireless remote microphone technology can significantly improve speech recognition performance in challenging listening environments for Mandarin speaking hearing aid users in China.
FRONTIERS IN NEUROSCIENCE
(2021)
Article
Audiology & Speech-Language Pathology
Hendrik Husstedt, Julia Kahl, Christina Fitschen, Sebastian Griepentrog, Marlitt Frenz, Tim Juergens, Juergen Tchorz
Summary: The study found no difference in speech intelligibility when using WRMS in an actual classroom compared to a simplified setup. An analog omnidirectional WRMS had poorer speech intelligibility and quality ratings than digital WMRSs. Using WRMS in the simplified setup resulted in significantly higher speech intelligibility across all tested background noise levels.
INTERNATIONAL JOURNAL OF AUDIOLOGY
(2022)
Article
Medicine, General & Internal
Karolina Dzaman, Marlena Ziemska-Gorczyca, Ireneusz Kantor
Summary: Hearing loss is a common cause of disability worldwide, and a study compared the demographic structure and hearing test results in people qualified for hearing aids over the past 25 years. The analysis of 1246 patients revealed that the first group had elevated air conduction thresholds, while the second group had increased bone conduction thresholds. Additionally, there were significant differences in gender distribution between the two groups, with modern women using hearing aids more frequently.
JOURNAL OF CLINICAL MEDICINE
(2023)
Article
Engineering, Multidisciplinary
Shufeng Wu, Qinyu Qiao, Guochang Liu, Haoyu Tan, Guojun Zhang, Wendong Zhang, Renxin Wang
Summary: This paper proposes a MEMS co-vibration combined hydrophone (CCH) for precise positioning of weak acoustic sources in small-volume UUV acoustic self-guided cabins. The CCH consists of a MEMS triaxial accelerometer and a MEMS capacitive omnidirectional microphone. The packaging of the CCH is designed based on the acoustic receiving model of an elastic-free sphere in water. The experimental results demonstrate that the CCH can meet the need for sound source detection and has specific application value.
Article
Materials Science, Ceramics
Madeshwaran Sekkarapatti Ramasamy, Ashiqur Rahaman, Byungki Kim
Summary: This study presents an effective method for improving the mechanical strength and piezoelectric response of poly(vinylidene fluoride) nanofibers (PVDFNFs) by incorporating phenylisocyanate functionalized graphene oxide (IGO) as a nanofiller. The addition of IGO resulted in a significant increase of 303% and 332% in the ultimate tensile strength and modulus of PVDFNFs, respectively, as well as enhanced acoustic sensitivity of the composites.
CERAMICS INTERNATIONAL
(2021)
Review
Engineering, Electrical & Electronic
Ashiqur Rahaman, Byungki Kim
Summary: This paper reviews recent biomimetic sound source localization approaches, discusses the necessity of biomimetic SSL, and evaluates the merits and demerits of each technique. The future perspective is also presented for designing next-generation microscale devices for biomimetic SSL.
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
(2022)
Article
Materials Science, Biomaterials
Madeshwaran Sekkarapatti Ramasamy, Vignesh Krishnamoorthi Kaliannagounder, Ashiqur Rahaman, Chan Hee Park, Cheol Sang Kim, Byungki Kim
Summary: An efficient approach for fabricating high-performance PLLANF hybrid scaffolds for BTE by reinforcing amphiphilic triblock copolymer and PL-functionalized nanofillers has been reported. The synergistic effect of PL-cMWCNTs and PL-EBN in PLLANF showed remarkable enhancement in mechanical strength, wettability, and piezoelectric performances. The reported method holds great promise in tissue engineering applications with enhanced biocompatibility and osteogenic differentiation.
ACS BIOMATERIALS SCIENCE & ENGINEERING
(2022)
Article
Nanoscience & Nanotechnology
Ashiqur Rahaman, Byungki Kim
Summary: This paper investigates three-dimensional sound source localization using a mm-sized array of piezoelectric MEMS directional microphones inspired by the ears of the fly Ormia ochracea, achieving a high level of accuracy in experimental measurements.
MICROSYSTEMS & NANOENGINEERING
(2022)
Article
Materials Science, Ceramics
Ragu Sasikumar, Asif Ishfaque, Byungki Kim
Summary: The increased demand for electricity with low environmental impact has prompted researchers to focus on piezoelectric materials. In this study, reduced graphene oxide encapsulated with polydopamine and incorporated with zinc manganate hybrid nanocomposite was prepared. Flexible piezoelectric sensors were fabricated using a solution-casting method. The results showed improved sensitivity and potential for developing efficient piezoelectric nanogenerators.
CERAMICS INTERNATIONAL
(2023)
Article
Environmental Sciences
Sasikumar Ragu, Byungki Kim, Shen -Ming Chen, Asif Ishfaque, Kwang-Mo Kang
Summary: In this study, a novel sensor based on highly dispersed nitrogen-doped carbon quantum dots and Iron oxide was successfully synthesized for the electrochemical detection of ortho-Nitroaniline (o-NA). The sensor showed good limit of detection, linear range, and sensitivity, providing an accurate detection method for o-NA in aqueous medium to avoid potential hazards.
Article
Chemistry, Physical
Varuna Jayachandran, Vishnu Shankar Dhandapani, Elango Muniappan, Dongkyou Park, Byungki Kim, A. P. Arun, P. R. Ayyappan
Summary: CeO2-SnO2/Al2O3 (CTA) mixed oxides were prepared and coated on stainless steel filter plates for diesel exhaust control. The CeO2-SnO2/Al2O3 (Ce/Sn-1:1) sample exhibited cubic and tetragonal mixed faces, enhancing redox nature and catalytic activities. The sample showed a small particle size of 10.22 nm and a high surface area of about 73 m(2) g(-1), demonstrating appreciable catalytic properties.
Article
Engineering, Electrical & Electronic
Asif Ishfaque, Byungki Kim
Summary: This paper presents a unique approach for sound source localization using a fly-inspired MEMS directional microphone. The system utilizes a rotational stage and intensity differences to accurately locate sound sources. With low computational time, a single microphone, and high accuracy, this system provides a simple and effective solution for sound localization in human-robot interactions.
IEEE SENSORS LETTERS
(2023)
Article
Instruments & Instrumentation
Hyun-U Ko, Inho Yoon, Byungki Kim, Youn-Hee Han, Sung Jea Park, Ho-Jin Hwang, Sang-Youn Kim
Summary: This study proposes a small haptic knob that utilizes magnetorheological fluids to provide kinesthetic torque feedback and vibrotactile feelings. The introduction of a novel rotation shaft structure with blades enables dual operation modes of the MRF (shear and flow) for actuation. Simulation analysis is used to investigate the combination mode in the haptic knob and optimize the blade angle for maximum resistive torque. Experimental studies confirm the optimal angle and demonstrate an increase in kinesthetic torque from 0.002 to 0.2 N m as the current input is increased from 0 to 1.28 A. The haptic knob also achieves strong and stable vibrotactile feedback in the frequency range of 1-50 Hz.
SMART MATERIALS AND STRUCTURES
(2023)
Article
Chemistry, Physical
Sanjeevi Palanisami, Vishnu Shankar Dhandapani, Varuna Jayachandran, Elango Muniappan, Dongkyou Park, Byungki Kim, Kalpana Govindasami
Summary: This report presents a method to reduce the use of highly toxic lead in diagnostic X-ray shielding by developing a cost-effective and eco-friendly nano-tungsten trioxide (WO3) epoxy composite for low-weight aprons. Zinc (Zn)-doped WO3 nanoparticles were synthesized using a cheap and scalable chemical acid-precipitation method. The prepared nanoparticles were dispersed in a non-water soluble durable epoxy resin polymer matrix and coated on a rexine cloth. The study showed improved X-ray attenuation in the range of 40-100 kVp for both undoped and Zn-doped WO3 nanoparticles, making them comparable to lead oxide-based aprons. The 2% Zn-doped WO3 epoxy composite exhibited better particle size distribution, mass attenuation coefficient, and lower half value layer, making it a convenient lead-free option for X-ray shielding aprons.
Article
Polymer Science
Madeshwaran Sekkarapatti Ramasamy, Vignesh Krishnamoorthi Kaliannagounder, Shanmugam Ramasamy, Vineet Kumar, Sung Jea Park, Sang Shin Park, Chan Hee Park, Sung Soo Han, Cheol Sang Kim, Byungki Kim
Summary: Due to their excellent properties, boron nitride (BN) nanostructures have been widely studied in biomedical applications, such as composites, drug delivery, and cell stimulation. However, the agglomeration tendency of BN in solvents limits their dispersibility and interaction with polymer matrix. In this study, BN nanosheets were efficiently functionalized with oleylamine (OLA) and pluronic F127 (PLU), and the resulting composites showed improved physiochemical, mechanical, and piezoelectric properties. In vitro studies demonstrated the biocompatibility and osteogenic differentiation potentials of the composite scaffolds. This strategy could be applied for the development of BN-based biopolymer composites in tissue engineering.
JOURNAL OF APPLIED POLYMER SCIENCE
(2023)
Article
Engineering, Environmental
Ragu Sasikumar, Byungki Kim
Summary: Harmful nitroaniline isomers that are highly toxic to the environment are commonly found due to improper industrial waste disposal. A new electrocatalyst called BN@MoS2 ND has been developed for the simultaneous detection of o-NA and p-NA in different water samples. The synthesized nanodisk exhibited excellent electron transfer and increased surface area. The proposed sensor showed a good linear range, detection limit, and sensitivity for both o-NA and p-NA, with good recoveries in water samples.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2023)
Article
Chemistry, Physical
Vishnu Shankar Dhandapani, Ramesh Subbiah, Elangovan Thangavel, Chang-Lae Kim, Kyoung-Mo Kang, Veeravazhuthi Veeraraghavan, Kwideok Park, Dae-Eun Kim, Dongkyou Park, Byungki Kim
Summary: This study evaluated the tribological properties and preosteoblast behavior of an amorphous carbon coating on a Si (100) substrate deposited by RF magnetron sputtering. The coatings' amorphous nature was confirmed by Raman analysis. The results showed that the tribological behavior and biocompatibility of the coating were highly dependent on the target power of the graphite.
Article
Polymer Science
Madeshwaran Sekkarapatti Ramasamy, Vignesh Krishnamoorthi Kaliannagounder, Shanmugam Ramasamy, Vineet Kumar, Sung Jea Park, Sang Shin Park, Chan Hee Park, Sung Soo Han, Cheol Sang Kim, Byungki Kim
Summary: Due to their excellent mechanical properties, good biocompatibility, biodegradability, and piezoelectric behavior, boron nitride (BN) nanostructures have attracted significant attention in the biomedical field. However, functionalization of BN is crucial to overcome their agglomeration tendency and enhance their interaction with polymer matrix. In this study, BN nanosheets (BNNS) were dual functionalized with oleylamine (OLA) and pluronic F127 (PLU) via Lewis acid-base interactions and noncovalent interactions, respectively. The PLU-functionalized BN nanosheets (PLUBN) were incorporated into a poly(L-lactic acid) nanofiber matrix, and their physiochemical, mechanical, and piezoelectric properties were investigated. Furthermore, in vitro studies demonstrated the biocompatibility and osteogenic differentiation potential of the composite scaffolds. The reported strategy holds promise for the development of BNNS-based piezoelectric biopolymer composites for tissue engineering applications.
JOURNAL OF APPLIED POLYMER SCIENCE
(2023)
Article
Chemistry, Physical
Ragu Sasikumar, Byungki Kim, Roshan Mangal Bhattarai
Summary: The global spread of COVID-19 has caused significant economic and health impacts, especially on the respiratory system. To address this challenge, researchers have developed a self-powered energy harvesting device based on FPENG and a smart mask for monitoring human breath.
