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Martin Pekař, Alexander F Kolen, Harm Belt, Frank van Heesch, Nenad Mihajlović, Imo E Hoefer, Tamas Szili-Török, Hendrik J Vos, Johan G Bosch, Gijs van Soest, Antonius F W van der Steen
In intracardiac echocardiography (ICE) it may be beneficial to generate ultrasound images acquired at multiple frequencies, having the possibility of high penetration or high-resolution imaging in a single device. The objective of the presented work is to test two frequency-tunable probe prototypes in a preclinical setting: a rigid probe having a diameter of 11 mm and a new flexible and steerable 12-Fr ICE catheter. Both probes feature a forward-looking 32-element capacitive micromachined ultrasonic transducer array (aperture of 2 × 2 mm(2)) operated in collapse mode, which allows for frequency tuning in the 6-MHz-18-MHz range...
June 20, 2017: Ultrasound in Medicine & Biology
Da-Chen Pang, Cheng-Min Chang
This paper presents the world's first transparent flexible capacitive micromachined ultrasonic transducer (CMUT) that was fabricated through a roll-lamination technique. This polymer-based CMUT has advantages of transparency, flexibility, and non-contacting detection which provide unique functions in display panel applications. Comprising an indium tin oxide-polyethylene terephthalate (ITO-PET) substrate, SU-8 sidewall and vibrating membranes, and silver nanowire transparent electrode, the transducer has visible-light transmittance exceeding 80% and can operate on curved surfaces with a 40 mm radius of curvature...
June 20, 2017: Sensors
Junhong Li, Wei Ren, Guoxiang Fan, Chenghao Wang
A square piezoelectric composite diaphragm was analyzed by the finite element method to enhance the sensitivity of a piezoelectric micromachined ultrasound transducer (pMUT). The structures of electrode and piezoelectric film were optimized and a centric electrode was designed to avoid the counteraction of stress in the centre and edges. In order to further improve the sensitivity; a pMUT with partially-etched piezoelectric film was adopted. The receive and transmit sensitivities of the pMUT were analyzed in details...
June 14, 2017: Sensors
Tong Lu, Eric Markvicka, Yichu Jin, Carmel Majidi
When encapsulated in elastomer, micropatterned traces of Ga-based liquid metal (LM) can function as elastically deformable circuit wiring that provides mechanically robust electrical connectivity between solid state elements (e.g. transistors, processors, sensor nodes). However, LM-microelectronics integration is currently limited by challenges in rapid fabrication of LM circuits and the creation of vias between circuit terminals and the I/O pins of packaged electronics. In this study we address both with a unique layup for soft-matter electronics in which traces of liquid-phase Ga-In eutectic (EGaIn) are patterned with UV laser micromachining (UVLM)...
June 12, 2017: ACS Applied Materials & Interfaces
Yoshitaka Yoshizumi, Hiroaki Suzuki
Two self-propelled micromachines were fabricated with gold/platinum micromotors that exhibit simple translational motion in a fuel solution. In each one, two micromotors were connected with a joint of polymer tube formed by stacking cationic poly(allylamine hydrochloride) (PAH) and anionic poly(acrylic acid) (PAA) using a layer-by-layer technique. A bent structure was created by making one longitudinal side of the joint more swellable with alkaline treatment. The joint containing fewer PAA/PAH bilayers was flexible and allowed a larger range of Brownian angular fluctuation...
June 16, 2017: ACS Applied Materials & Interfaces
Suleman Ayub, Luc J Gentet, Richárd Fiáth, Michael Schwaerzle, Mélodie Borel, François David, Péter Barthó, István Ulbert, Oliver Paul, Patrick Ruther
This article reports on the development, i.e., the design, fabrication, and validation of an implantable optical neural probes designed for in vivo experiments relying on optogenetics. The probes comprise an array of ten bare light-emitting diode (LED) chips emitting at a wavelength of 460 nm and integrated along a flexible polyimide-based substrate stiffened using a micromachined ladder-like silicon structure. The resulting mechanical stiffness of the slender, 250-μm-wide, 65-μm-thick, and 5- and 8-mm-long probe shank facilitates its implantation into neural tissue...
September 2017: Biomedical Microdevices
Stephen H Simpson, Pavel Zemánek, Onofrio M Maragò, Philip H Jones, Simon Hanna
Multiple scattering of light induces structured interactions, or optical binding forces, between collections of small particles. This has been extensively studied in the case of microspheres. However, binding forces are strongly shape dependent: here, we turn our attention to dielectric nanowires. Using a novel numerical model we uncover rich behavior. The extreme geometry of the nanowires produces a sequence of stationary and dynamic states. In linearly polarized light, thermally stable ladder-like structures emerge...
June 14, 2017: Nano Letters
Arvind Chandrasekaran, Nikita Kalashnikov, Roni Rayes, Claire Wang, Jonathan Spicer, Christopher Moraes
Innovation in microfluidics-based biological research has been aided by the growing accessibility of versatile microscale fabrication techniques, particularly in rapid prototyping of elastomeric polydimethylsiloxane (PDMS) based devices. However, the use of PDMS presents considerable and often unexpected limitations, particularly in interpreting and validating biological data. To rapidly prototype microfluidic culture systems in conventional plastics commonly used in cell culture, we developed 'thermal scribing', a one-step micromachining technique in which thermoplastics are locally patterned by a heated tip, moving in user-controlled patterns...
May 31, 2017: Lab on a Chip
Xiaoyue Jiang, Hao-Yen Tang, Yipeng Lu, Eldwin Ng, Julius Tsai, Bernhard Boser, David Horsley
In this paper, we present a single-chip 65x42 element ultrasonic pulse-echo fingerprint sensor with transmit beamforming based on piezoelectric micromachined ultrasonic transducers (PMUTs) directly bonded to a CMOS readout ASIC. The readout ASIC was realized in a standard 180 nm CMOS process with a 24V high voltage transistor option. Pulse-echo measurements are performed column-by-column in sequence using either one column or five columns to transmit the ultrasonic pulse at 20 MHz. Transmit beamforming is used to focus the ultrasonic beam at the imaging plane where the finger is located, increasing the ultrasonic pressure and narrowing the 3dB beam-width to 50 microns, a factor of 6...
May 11, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Christopher Ceroici, Roger J Zemp
Capacitive micromachined ultrasonic transducers (CMUTs) promise many advantages over traditional piezoelectric transducers such as the potential to construct large, cost-effective 2D arrays. To avoid wiring congestion issues associated fully wired arrays, Top-Orthogonal-to-Bottom Electrode (TOBE) CMUT array architectures have proven to be a more practical alternative, using only 2N wires for an NxN array. Optimally designing a TOBE CMUT array is a significant challenge due to the range of parameters from the device level up to the operating conditions of the entire array...
May 9, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Chupao Lin, Changrui Liao, Jia Wang, Jun He, Ying Wang, Zhengyong Li, Tianhang Yang, Feng Zhu, Kaiming Yang, Zhe Zhang, Yiping Wang
A fiber surface Bragg grating waveguide (BGW) fabricated in the surface of single-mode fiber by direct femtosecond laser inscription is demonstrated and successfully applied for refractive index (RI) measurements. Prior to laser inscription of the fiber surface BGW, an X-coupler is first inscribed across the fiber core to couple light from the core to the fiber surface. The light transmitted in the fiber surface BGW efficiently interacts with the surrounding medium due to a strong evanescent field, and obtains an acceptable RI sensitivity approaching ∼16  nm/RIU...
May 1, 2017: Optics Letters
Emil Karshalev, Chuanrui Chen, Gregor Marolt, Aída Martín, Isaac Campos, Roxanne Castillo, Tianlong Wu, Joseph Wang
All-in-one material for microrocket propulsion featuring acid-based bubble generation and magnetic guidance is presented. Electrochemically deposited iron serves as both a propellant, toward highly efficient self-propulsion in acidic environments, and as a magnetic component enabling complete motion control. The new microrockets display longer lifetime and higher propulsion efficiency compared to previously reported active metal zinc-based microrockets due to the chemical properties of iron and the unique structure of the microrockets...
June 2017: Small
Petra Paiè, Francesca Bragheri, Theo Claude, Roberto Osellame
Microfluidic lenses are relevant optical components for sensing application in lab-on-a-chip devices, guaranteeing a robust alignment of the elements, a high level of compactness and tunable optical properties. In this work we describe an innovative integrated in-plane microfluidic lens. The device shows both an optimized shape capable of reducing spherical aberrations and periodically tunable optical properties. Indeed through the combination of the lens with a droplet generator module, we have been able to obtain an integrated optofluidic modulator capable of both on-demand on/off switching and periodic modulation of light...
April 3, 2017: Optics Express
S Elhadj, W A Steele, D S VanBlarcom, R A Hawley, K I Schaffers, P Geraghty
We investigate an approach for the recycling of laser-damaged large-aperture deuterated potassium dihydrogen phosphate (DKDP) crystals used for optical switching (KDP) and for frequency conversion (DKDP) in megajoule-class high-power laser systems. The approach consists of micromachining the surface laser damage sites (mitigation), combined with multiple soaks and ultrasonication steps in a coating solvent to remove, synergistically, both the highly adherent machining debris and the laser-damage-affected antireflection coating...
March 10, 2017: Applied Optics
Yang Chen, Mohammed F Saleh, Nicolas Y Joly, Fabio Biancalana
We introduce a novel design of anti-resonant fibers with negative-curvature square cores to be employed in 1.55 and 2.94 μm transmission bands. The fibers have low losses and single-mode operation via optimizing the negative curvature of the guiding walls. The first proposed fiber shows a broadband transmission window spanning 0.9-1.7 μm, with losses of 0.025 and 0.056 dB/m at 1.064 and 1.55 μm, respectively. The second proposed fiber has approximately a 0.023 dB/m guiding loss at 2.94 μm with a small cross-sectional area, useful for laser micromachining applications...
April 1, 2017: Optics Letters
Qiu Xu, Zhuoqing Yang, Yunna Sun, Liyan Lai, Zhiyu Jin, Guifu Ding, Xiaolin Zhao, Jinyuan Yao, Jing Wang
This paper presents a novel MEMS-based inertial microswitch design with multi-directional compact constraint structures for improving the shock-resistibility. Its shock-resistibility in the reverse-sensitive direction to ultra-high g acceleration (~hunderds of thousands) is simulated and analyzed. The dynamic response process indicates that in the designed inertial microswitch the proof mass weight G, the whole system's stiffness k and the gap x2 between the proof mass and reverse constraint blocks have significant effect on the shock-resistibility...
March 31, 2017: Scientific Reports
Omid Farhanieh, Ali Sahafi, Rupak Bardhan Roy, Arif Sanli Ergun, Ayhan Bozkurt
Conventional High Intensity Focused Ultrasound (HIFU) is a therapeutic modality which is extracorporeally administered. In applications where a relatively small HIFU lesion is required, an intravascular HIFU probe can be deployed to the ablation site. In this paper, we demonstrate the design and implementation a fully integrated HIFU drive system on a chip to be placed on a 6 Fr catheter probe. An 8-element capacitive micromachined ultrasound transducer (CMUT) ring array of 2 mm diameter has been used as the ultrasound source...
June 2017: IEEE Transactions on Biomedical Circuits and Systems
Hafeez Ul Hassan, Amédée Lacraz, Kyriacos Kalli, Ole Bang
No abstract text is available yet for this article.
March 1, 2017: Journal of Biomedical Optics
A Forget, A L S Burzava, B Delalat, K Vasilev, F J Harding, A Blencowe, N H Voelcker
Cell aggregates reproduce many features of the natural architecture of functional tissues, and have therefore become an important in vitro model of tissue function. In this study, we present an efficient and rapid method for the fabrication of site specific functionalised poly(dimethylsiloxane) (PDMS) microwell arrays that promote the formation of insulin-producing beta cell (MIN6) aggregates. Microwells were prepared using an ice templating technique whereby aqueous droplets were frozen on a surface and PDMS was cast on top to form a replica...
March 9, 2017: Biomaterials Science
Qiu Xu, Zhuo-Qing Yang, Bo Fu, Yan-Ping Bao, Hao Wu, Yun-Na Sun, Meng-Yuan Zhao, Jian Li, Gui-Fu Ding, Xiao-Lin Zhao
A novel micro-electro-mechanical systems (MEMS) inertial microswitch with a flexible contact-enhanced structure to extend the contact duration has been proposed in the present work. In order to investigate the stiffness k of the stationary electrodes, the stationary electrodes with different shapes, thickness h, width b, and length l were designed, analyzed, and simulated using ANSYS software. Both the analytical and the simulated results indicate that the stiffness k increases with thickness h and width b, while decreasing with an increase of length l, and it is related to the shape...
March 7, 2017: Sensors
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