High-power millisecond laser is an efficient tool to manufacture micro holes, but the laser induced thermal defects, such as recast layer (RL), micro cracks and heat affected zone, are difficult to avoid. However, some important components, like turbine blades, are very sensitive to these defects, therefore, they must be eliminated in the manufacturing process of film cooling holes. We propose a combined

This paper introduces the deep isotropic chemical etching (DICE) process developed for wafer-scale manufacturing of highly symmetric hemispherical silicon molds. The DICE process uses silicon nitride concentric rings as a masking layer during hydrofluoric, nitric, acetic etching of silicon substrate. These concentric rings pop up and widen the etch aperture as etch depth increases, thereby allowing

The booming growth in environmental conditions sensing and monitoring pushes the need of inexpensive environment sensors with small size and low power consumption. The outbreak of COVID-19 further increases the need for fast monitoring of environment conditions. The micro-electrical-mechanical-systems (MEMS) technologies are considered as promising solutions to realize the required environment sensors

Acoustofluidic devices based on surface acoustic waves (SAWs) have been widely applied in biomedical research for the manipulation and separation of cells. In this work, we develop an accessible manufacturing process to fabricate an acoustofluidic device consisting of a SAW interdigital transducer (IDT) and a polydimethylsiloxane microchannel. The IDT is manufactured using a flexible printed circuit

A novel underwater composite anechoic layer is proposed by inserting periodically placed longitudinal parallel steel plates into a viscoelastic rubber matrix. Built upon the complex viscosity model of viscoelastic materials, a theoretical model is established to evaluate the sound absorption performance of the proposed anechoic layer. For validation, finite element simulations are carried out, and

Microneedles are able to penetrate into the skin and offer great chances in various biomedical applications including transdermal drug delivery, stable bio-signal monitoring, sampling and bio-sensing. Owing to the micro-scale feature size, microneedles have advantages of minimal invasiveness, pain, high biosafety and simple operation. However, it is still challenging to fabricate solid microneedles

The soft lithographic fabrication of high-aspect-ratio polydimethylsiloxane (PDMS) microstructures is quite challenging because of the strong interfacial adhesion between them and masters during demolding. This paper presents a simple method for fabricating high-aspect-ratio PDMS microstructures by reducing the interfacial adhesion through the cooling process. The effect of cooling process on the topography

In this work, we propose a new optical measurement method and setup to investigate the dynamic behavior of a pneumatically driven diaphragm micropump in a microfluidic system. The presented method allows a contact-free spatially and temporally resolved determination of the membrane displacement. Hence, it enables to derive the volume flow rate, generated by the micropump. The method is based on the

In this paper, we report an actuator with a magnet made of novel rare earth magnetic powder Sm-Fe-N with diameter of 2 m to 5 m. Micro magnets were fabricated by mixing the magnetic powder with wax at temperature of 90 C. Alignment of the easy axis process was employed to enhance the remanence of the micro magnets. A 8 T strong pulse magnetic field was utilized to magnetize the micro magnets. The properties

Recently, flexible electronics have attracted significant attention as they can be integrated on diverse platforms from curved to flexible surfaces. As flexible electronics are used on a curved surface of wearable or manufacturing devices for health and system monitoring, the working environment of such applications forces electronics to be exposed to diverse stimuli such as deformation, temperature

While wet pattern transferring of polymers is faster than dry processing, it can lead to excessive undercut that will erode and distort features in patterned sacrificial regions during micro electro mechanical systems (MEMSs) fabrication. Dry etching processes based on O2, CF4 and N2 chemistry reduce undercutting of features to around 2 m, but the resulting sidewall profiles of the patterned polymer

The structure design of micro cantilever beams(MCBs), which has a significant effect on MCBs’ controllable actuation range, is usually restricted by the establishment of the inner electric circuit. This paper proposes the design of a micro electro-controllable twisting cantilever beam (METCB). The architecture and the fabrication diagram of the proposed METCB are presented before its features are theoretically

Micro electromechanical system (MEMS) based optical phased array (OPA) technology generally demands narrow and tightly spaced suspended microstructures with high-aspect-ratio in the lateral dimensions. This paper presents an one dimensional OPA system which is fabricated using the standard PolyMUMPs process, leading to a low-cost, simplified and commercially accessible surface micromachining technique

We developed a local irradiation system for atmospheric pressure inductively coupled plasma (ICP) using a quartz capillary nozzle (nanopipette) with a sub-micrometer diameter tip aperture for fine processing of material surface. Using this system, a polymethyl methacrylate (PMMA) film coated on a glass substrate was etched at the micrometer scale. Fine etching was achieved by the ICP localized by the

Vibration assisted machining is an advanced non-conventional precision machining technique aiming at improving the machining performance by superimposing a small amplitude, high-frequency vibration either on the tool or on the workpiece. This article presents the mechanical design, electromechanical simulation, and experimentation on the developed prototype of the flexural hinged micro XY stage for

To measure the distance of an object, we propose a distance sensor that combines a tunable aperture operated by the thermal expansion of silicon chevron beams with a commercial camera similar to the automotive black box. The distance sensor is composed of a tunable aperture, a lens with an 8 mm focal length, and a 1/4-inch full high definition image sensor, where a tunable aperture is attached to the

With the rapid development of the three-dimensional printing (3D printing) technique, several electronic devices have been fabricated by 3D printing. Compared with the traditional micro electromechanical system (MEMS) manufacturing processes, the 3D printing technique provides a convenient method to meet the customers’ personalized demands. However, the applications of 3D printing are restricted by

In this paper, an analytical method of resonant frequency, tuning range, the effective relative dielectric constant, and characteristic impedance is proposed, which is for coplanar waveguide (CPW) resonator loaded by defected ground structure (DGS) and micro-electromechanical systems (MEMS) capacitors. The analytical solution is achieved by an employing equivalent method. The resonant frequency, tuning

During the cutting process of the original molds, the micro-burrs produced by the machining process will affect the optical properties of the optical functional textured film. According to the forming planing method for the triangular pyramid texture, the formation characteristics of burrs are analyzed from the cut-in edge and the cut-out edge. And the influence of burrs on the triangular pyramid edge

The force-to-rebalance (FTR) closed-loop detection method is commonly used to expand the bandwidth (BW) for micro-electro-mechanical system (MEMS) gyroscopes with low-frequency split and high-quality factors. However, the relationship between the BW and output noise is often incompatible; thus, reducing the detection accuracy of the gyroscope. This paper presents an analysis of the BW and noise spectra

In this paper, the simple, rejection-based kinetic Monte Carlo simulation method is applied for the approximate simulation of the etch rates and three-dimensional etch structures during anisotropic wet etching of sapphire. Based on the analysis of the composition of the atomic structure of sapphire, a model of the simplified atomic structure of sapphire is proposed, which reduces the difficulty of

Dielectric elastomer actuators fabricated from thin and miniaturized metal electrodes integrated with highly soft and stretchable elastomers offer the promise of opening new possibilities in the field of microrobotics. To achieve large displacements O(10−4) m at actuation voltages O(103) V in actuators with thin metal electrodes, the approach of distributed electrode array with fractal interconnects

Based on the resonant electric field microsensors with coplanar electrodes, a novel non-intrusive measurement scheme of DC power-line voltage suitable for actual product is presented in this paper. Compared with using microsensors directly without some protection, employing the proposed scheme can avoid the influence of humidity and electromagnetic disturbance on non-contact voltage measurement. A

Droplet motion has been a long-standing interest in microfluidics as it is often limited by the high operating voltages, which hampers the development of consumer applications. Forces generated by liquid dielectrophoresis (L-DEP) can enhance surface wetting, without requiring chemical modification or surface texturing. This work presents a droplet actuating platform to control the wetting behaviour

This work investigates the design methodology to obtain large electromechanical coupling factor () and high quality factor (Q) of shear-horizontal surface acoustic wave (SH-SAW) resonators based on the thin-film lithium niobate-on-insulator (LNOI) technology. The guided SH wave can be excited through interdigital transducers and propagate at the very surface of the material stackings. Such a guided

We report on a piezoelectric micromachined ultrasonic transducer (PMUT) driven in a nonlinear regime, generating chaotic amplitude modulated ultrasonic waves. At large enough drives, the PMUT enters in the Duffing regime which opens a hysteresis with two available states. By modulating the frequency of the driving signal, the system may switch between both states, and selecting the appropriate modulation

In this work, a novel on-chip micro pressure sensor was developed for microfluidic pressure monitoring. Polydimethylsiloxane (PDMS) microfluidic chip contained a working fluid channel with a sealed detection channel beneath it. Any change in pressure in the working fluid channel would change the volume of the detection channel. A mixture of two immiscible fluids was sealed in the detection channel

Rapid detection of small amounts of Staphylococcus aureus (S. aureus) in whole blood and the corresponding diagnosis of S. aureus is a complicated and time-consuming process. Gold standard is to culture and grow bacteria before detection, which typically takes several days and requires skilled personnel. Here, we developed a microfluidic cartridge for the culture-free isolation of S. aureus in blood

Patterning using a focused ionizing radiation beam provides a high spatial resolution but is not feasible when creating large arrays of microstructures. We propose the optimization of x-ray lithography parameters to create submicropores in a low-sensitivity material (polyethylene terephthalate) using a wide x-ray beam. This optimization results in the fabrication of regularly arranged micropores with

Bottom-up grown single-crystalline silicon nanowires (SiNWs) are highly intriguing to build nanoscale probes, for instance for atomic force microscopy (AFM), due to their mechanical robustness and high aspect ratio geometry. Several strategies to build such nanowire-equipped probes were explored but their fabrication is still elaborate, time-consuming and relies partly on single-crystalline substrates

A novel microfluidic device for efficient passive mixing is reported. A series of sharp corner structures designed on side wall of an arc microchannel was utilized to induce three-dimensional vortices, which strongly stretched and folded the interface and significantly increased the interfacial contact area between different fluids. Additionally, the sharp corner structure induced high radial velocity

Arrays of pn junctions have been fabricated with n-Si microneedles. In situ doping vapor–liquid–solid (VLS) growth has been carried out with p-Si substrate having metallic catalyst (Au) dots on its surface, using Si2H6 and PH3 for supplying Si and phosphorus to fabricate n-Si microneedles on the surface of p-Si substrate in vertical direction; thus, pn junctions have been fabricated at microneedle-substrate

Stenosis reduces the effective lumen area in the tracheal and bronchial segments of the airway anatomy. Loss in patency due to obstruction increases resistance to airflow; thus, severe narrowing is often associated with morbidity and mortality. Etiologies such as congenital tracheal stenosis, tracheomalacia, laryngeal and subglottic stenosis, atresia are few among the many pathologies causing major

In this paper, optoelectronic characteristics and related switching behavior of one monolithically integrated silicon light-emitting device (LED) with an interesting wavelength range of 400–900 nm are studied. Through the comparison of two types of geometry, Si avalanche-based LED and Si field-effect LED (Si FE LED), in the same device, we establish the dimensional dependence of the switching speed

A mechanically reliable micrometric scale conductive wire fabrication method was developed using silver paste. In order to increase the bonding strength between silver particles, a method was developed for filling the space between particles with UV photopolymer. The UV photopolymer covers the top of a mold filled with silver paste, after which vacuum forces are generated by the evaporation of the

This work analyses circuit phase delay for carrier-modulation MEMS capacitive gyroscopes. The temperature-dependent circuit phase delay is a major source of gyroscope output drift, which deteriorates the gyroscope bias instability (BI) and angle random walk (ARW). Effects of both drive-mode and sense-mode circuit phase delay on gyroscope performance when using different signal extraction architectures

High frequency printed circuit board (PCB), as the significant support for 5G technology, has been receiving intense attention from the increasing number of scholars. Concerning precision fabrication of high frequency PCBs, micro hole drilling is deemed as one of the extremely crucial challenges. In this study, the coated drill bits’ wear and micro hole quality were investigated through the drilling

This paper reports on a rapid, lossless process for the bonding of poly(methyl methacrylate) (PMMA) substrates for use in microfluidic devices for blood tests, utilizing H2O plasma, and H2O linked rapid thermal annealing (RTA) treatments. The bonding of PMMA produced with H2O plasma linked with RTA was analyzed, and its effect on the bonding of free radicals was investigated. The PMMA surface treatment

This paper describes the investigation of a novel low-cost silicone-based hybrid vibration energy harvester (SHVEH) for converting machine vibrations into useful electrical power for wireless sensor nodes. Due to a novel fabrication technique, the harvester has the benefit of incorporating two transduction mechanisms (electromagnetic and piezoelectric) into a single silicone housing for improved output

Fused silica (FS) micro hemispherical resonators have attracted considerable interest for application in high-performance sensors. Manufacturing of resonators with extremely high quality factor and acceptable cost is currently the main challenge. Here, we demonstrate the application of ultrafast laser in manufacturing of three-dimensional (3D) FS micro hemispherical resonators with unrestricted edge

In this work, experimental data and finite element analysis reveals deflection in diaphragm supporting material leading to non-linear pressure-reflection response. These results are contrary to the standard assumptions presented in literature, where modelling of deflection response in diaphragm pressure sensors is primarily carried out assuming a rigid supporting structure. An extrinsic fiber-optic

Neural interfaces bridge the nervous system and the outside world by recording and stimulating neurons. Combining electrical and optical modalities in a single, hybrid neural interface system could lead to complementary and powerful new ways to explore the brain. This convergent approach has gained robust and exciting momentum recently in neuroscience and neural engineering research. Here, we review

This paper presents a novel LC-based passive wireless flexible pressure sensor that employs microstructured ferromagnetic films with tunable effective permeability. The proposed device consists of a micromachined planar spiral coil and a polymer film with cilia arrays (CAs) realized by the ferrofluidic instability principle. The effective permeability of the polymer film can be tuned by deforming the

Over the past two decades, researchers have advanced and employed integrated microfluidic circuitry to enable a wide range of chemical and biological ‘lab-on-a-chip’ capabilities. Yet in recent years, a wholly different field, soft robotics, has begun harnessing microfluidic circuitry as a promising means to enhance soft robot autonomy. Unfortunately, key challenges associated with not only the fabrication

In this paper, a novel micro-tensile testing apparatus is designed and built to characterize the micromechanical behavior of materials. Furthermore, a special geometry for micro specimens is introduced that could facilitate problems related to the handling, gripping, and aligning such specimens. The device can be integrated with an optical microscope to observe the microstructural evolution taking

Nano-resonators are increasingly used to study fundamental phenomena in dynamical systems. Strain tuning of resonance frequency provides an additional control knob in experiments that use these devices. In this work, we present a simple technique to tune the strain in these nano-resonators by controllably deforming a small section of the silicon substrate. We fabricate the graphene nano-resonators

Sophisticated three-dimensional microstructures fabricated using the negative tone SU-8 photoresist are used in many biomedical and microfluidic applications. Scanning electron microscopy (SEM) and profilometry are commonly used metrological techniques for the dimensional characterization of fabricated SU-8 microstructures but are not viable for non-destructive measurements and characterization of

Micro-electro-mechanical-systems (MEMS) structures with different in-plane dimensions often need to be released simultaneously from the bulk of the wafer and a single dry etching or wet etching technique cannot fulfill all release requirements. In this paper we present a universally applicable solution to release MEMS structures with different surface areas in a controlled and uniform way, which combines

Label-free cell separation is a promising method in the field of stem-cell research to obtain desired cell populations. Here, we report on phospholipid polymer-coated microfluidic channels with immobilized antibodies as devices for the capture of cells expressing target antigens in a label-free manner. We fabricated a microfluidic channel containing immobilized antibodies against vascular endothelial

A lot of mechanical energy is lost in the braking process of automobiles, and it is feasible to harvest the energy and power electronic devices by using the technology of a triboelectric nanogenerator (TENG). In this study, we propose a pulsed freestanding TENG (PF-TENG) with a grid structure to harvest mechanical energy in the braking process, and use electric brushes to achieve a unidirectional pulsed

Flexible electronics require more compact interconnects for next-generation devices. Polymer devices can be bonded to integrated circuit chips, but combining flexible and rigid substrates poses unique technical challenges. Existing technologies either cannot achieve the density required for modern chips or employ specialized equipment and complex processes to do so. Here, we adapt several approaches

Shock-free ion transmission from atmospheric pressure to a microelectromechanical system (MEMS)-based mass spectrometer has been achieved using micro-engineered nickel skimmers. The signal level has increased 70-fold compared with a previous configuration in which the skimmer did not sample the supersonic flow. The skimmers are formed by electroplating internal surfaces of anisotropically etched, pyramidal

The 3D bio-printing has been developed as an effective approach to artificially create tubular tissue structures, which have been frequently found in body and organ systems. China Agricultural University (CAU) has developed a laboratory 3D bio-printer that can create tubular structures with the encapsulation of microfluidic channel. In order to create a tubular structure with more effective micro-channel

Micro-droplet ejection is a liquid dispensing technology that has potential applications in many fields. Specifically, pneumatic ejection is actuated by a solenoid valve, which is set to ‘conduction’ state for a brief period of time Δt. High pressure gas of P 0 enters the liquid reservoir, then releases through a venting tube, creating a oscillating pressure waveform P(t), forcing the liquid out through

Diverse wetting contrasts of binary wettability patterns in nature have inspired a versatile platform for microfluidics manipulation. To date, nevertheless, building a binary wettability patterned micro/nano structure with highly ordered configuration has inevitably brought wettability contamination challenges in interface control. Herein, this work studied a facile approach to fabricate permanent

A high-accuracy differential resonant pressure sensor with two similar resonators is proposed using the linear fitting method to guarantee its output linearity without polynomial compensation. Results reveal that the nonlinearity of the differential resonant pressure sensor is largely dependent on the tensile/compressive sensor pressure–stress ratio c when two similar resonators are used separately

This paper presents a dual-frequency piezoelectric micromachined ultrasonic transducer (PMUT) line array with low crosstalk level, which was fabricated on silicon-on-insulator (SOI) wafers with sputtered piezoelectric thin film (PZT) and Si diaphragm structure. The obtained array consists of 120 of 0.77 MHz and 192 of 2.30 MHz PMUT units in total with minimum interspace of 50 μm. Due to the high piezoelectric

The weakly coupled resonators based on mode localization are promising in emerging signal measurement fields due to the verified relative mechanical sensitivity enhancement and exceptional ambient robustness. In this work, we report a novel mode localized artificial hair sensor for dual-axis air flow sensing. A new full-scale linear output metric based on differential subtraction of reciprocal amplitude

Residual stress gradients often negatively affect the performance of MEMS devices, causing film curvature and changing the designed gaps of released structures. In this work, we built folded beams designed to compensate for the film curvature and keep the actuator gaps of sensitive resonant switches constant. While the average stress gradient is cancelled by our designs, we find that random variations

In this paper, a novel optimization method, in which composed of the genetic algorithm, particle swarm optimization (GA–PSO) and improved gradient descent algorithm, are used to conduct a double-objective optimization for the U-shaped actuator. In the procedure of optimization, two objectives, i.e. force and displacement, and four main sizes are utilized. Before, the deep reactive-ion etch (DRIE) technology