The rotation of the helical micromachines can produce efficient motion efficiency at small-scale conditions and have the potential for multi-field applications. In this study, we propose self-scrolling schemes aiming at a flexible bilayer structure that includes the strained layer and magnetic layer. The magnetic layer is composed of magnetic nanocomposites and can respond to an external magnetic field

Micro-electromechanical-system (MEMS) based actuators, which transduce certain domains of energy into mechanical movements in the microscopic scale, are increasingly contributing to the areas of biomedical engineering and healthcare applications. They are enabling new functionalities in biomedical devices through their unique miniaturized features. An effective selection of a particular actuator, among

Micro-dimples are a specific class of surface textures that are ubiquitous in a wide range of applications where functionalities such as wetting, hydrodynamic drag reduction, and sliding friction reduction are needed. However, fabrication of the micro-dimples through the existing manufacturing techniques involves the use of complex equipment and requires relatively long cycle times. Consequently, we

In this study, a novel rotating permanent magnetic actuator (PMA) system is proposed to manipulate magnetic nanofluids to pump chemicals inside micro-sized channels with circular paths. The PMA consists of two permanent magnet pairs and a rotor-like structure. A semicircular-shaped microchannel with a square cross-section area is located at the top of the actuator in order to investigate the performance

Rapid, portable, and sensitive biosensors for the detection of cardiac biomarkers are important for early diagnosis of cardiovascular diseases. We demonstrate a micro-electromechanical film electroacoustic resonator for heart-type fatty acid-binding protein assays. This device combines an immunologic sensitive element with the resonator working in biological liquids. Based on the mass-sensitive mechanism

This paper reports on frequency tunable MEMS magnetoelectric (ME) sensors. Different designs are studied in respect to ME voltage coefficient and frequency tunability. Compared to state-of-the-art ME sensors, the presented ME resonators display a highly reversible and linear frequency tuning, enabled by applying a DC voltage to piezoelectric actuators. A frequency shift of up to 0.2 Hz V −1 is demonstrated

Cellular metamaterial structures with sub-micron features have shown the ability to become excellent energy absorbing materials for impact mitigation due to the enhanced mechanical properties of materials at the nanoscale. However, in order to optimize the design of these energy absorbing metamaterial structures we need to be able to measure the dynamic properties of the sub-micron features such as

The manufacture of inertial-grade and tactical-grade diamond micro electro mechanical systems (MEMS) hemispherical resonator gyroscopes is limited by the manufacturing accuracy of the monocrystalline silicon hemispherical concave mold, on which the gyroscope shell is formed. To solve this problem, this paper presents a new method for micro-ultrasonic machining of microhemispherical molds for resonator

We present a compact tunable Fabry–Pérot filter operating at mid-infrared wavelengths (3–5 µ m) with novel actuators based on liquid crystal elastomers (LCEs). These are a new class of shape-memory materials with potential for achieving large reversible actuation based on different external stimuli. For actuating the Fabry–Pérot filter, microheaters and thermo-actuated LCE layers were fabricated as

The combustion of a micro-piston internal combustion engine with platinum wire glow ignition is diagnosed. The results show that the combustion starting point of the micro piston internal combustion engine varies greatly, and the combustion duration is various and long. The coefficient of variation of p max is as high as 28.5%, the combustion stability is poor. Therefore, it is suggested to improve

This paper presents a non-volatile mechanical memory bit that uses a bistable beam that buckles into one of two stable positions. The beam buckles because of compressive stress that is applied by oxidizing the silicon beam. In order to process a wafer with a released, buckled beam, it was necessary to use a stencil mask for the last steps to minimize damage to the device. The stencil mask is used to

Paschen’s law and deviation from Paschen’s law are studied in a face to face gas sensor based on Mn helical sculptured thin films with conical shape as cathode and anode electrodes. The sensor’s performance was investigated at dynamic pressures ranging from 0.1 to 1000 mbar and 3 to 200 μ m gaps between the two electrodes and for nitrogen, air and carbon monoxide gases. Results showed that at distances

In this research, the size effect in the micro-upsetting process of oxygen-free high conductivity copper has been investigated numerically and experimentally. For the numerical part of this study, the crystal plasticity finite element (CPFE) method was employed and grains were produced using the Voronoi algorithm. The homogenization method was used for curve fitting and to obtain the material-hardening

Multilayer interconnections are needed for microdevices with a large number of independent electrodes. A multi-level photolithographic process is commonly employed to provide multilayer interconnections in integrated circuit devices, but it is often too expensive for large-area or disposable devices frequently needed for microfluidics. The printed circuit board (PCB) can provide multilayer interconnection

Vibrational modes of higher order in micromachined resonators exhibit low damping in liquid environments, which facilitates accurate sensing even in highly viscous liquids. A steady increment in mode order, however, results in sound dissipation effects at a critical mode number n crit , which drastically increases damping in the system. Basic understanding in the emerging of sound dissipation in micromachined

This paper presents a tiny 0.4 mm × 0.4 mm piezoresistive absolute pressure sensor chip with a fabrication cost as low as 0.01 US$/die. With the thin-film under bulk-silicon technique, a very thin but uniform poly-silicon pressure-sensing diaphragm is formed beneath a bulk-silicon beam-island structure to accommodate piezoresistors. The thin diaphragm exhibits a high sensitivity, and the beam-island-reinforced

The mechanical and interfacial properties of metal films on polymer substrates under combined loading directly affect the function and service life of a variety of devices. However, the temperature effects on the failure mechanisms of brittle films are still unclear. Titanium films with three different thicknesses (100, 250 and 400 nm) were deposited on polymethylmethacrylate substrates; in-situ mechanical–thermal

In this study, the sinusoidal wavy (SW) copper microchannels with triangular cross section were fabricated with the ultrafast laser micromachining approach. The flow boiling of de-ionized water in SW microchannels were experimentally studied under mass fluxes of 43.43–217.15 kg (m 2 s) −1 and heat fluxes of 0–590 kW m −2 . The flow patterns in the SW microchannels were visually observed and the boiling

Nanoimprint lithography (NIL) is a useful technique for nano/micropattern replication. For ultraviolet-NIL (UV-NIL), the volume shrinkage of the resist upon curing is strongly affected by the applied UV exposure, possibly due to the various degrees of cross-linking. The applied UV intensity also influences the mechanical behaviors of the cured resist and the demolding force separating between the mold

Microfluidic technology has gradually become one of the most promising and convenient methods to generate monodisperse droplets, but even so, stable preparation in a microfluidic device is still technically challenging. This paper developed a simple coaxial microfluidic device, only composed of commercial parts, which can readily be assembled, adjusted and cleaned. Based on this design, the effects

Silver (Ag) micro-nano structure array is widely adopted in surface-enhanced Raman scattering (SERS) substrate for biological detection applications. The high-precision and high-efficiency construction of an ordered Ag micro-nano structure array becomes a crucial problem to be solved. In this study, the roll-to-plate (R2P) process was adopted for high-resolution and high-throughput fabrication of an

Water droplets are ubiquitous in nature and harvesting droplet kinetic energy has attracted a great deal of attention to meet the increasing worldwide energy demands. In this work, we report a water droplet motion energy harvester with the wafer-level fabrication method, which is based on the water–solid surface contact electrical double layer effect. A theoretical model is established to illuminate

Surface with oil–water separation performance has attracted more and more attention in the application of oil-containing wastewater purification. Much related work has been done by many researchers. However, there are still many difficulties in rapid manufacturing of filter membranes with special wettability. In this paper, an efficient, flexible method to fabricate microporous arrays by using a femtosecond

In micro–nano manufacturing, the deposition rate is one of the most basic parameters for the preparation of the film. In this paper, we use the tungsten–rhenium (W-5Re and W-26Re) alloy thin films as the research object and choose direct current (DC) magnetron sputtering to fabricate films on the alumina substrate. With the help of three factors and three levels of an orthogonal table, nine orthogonal

In micro electrochemical machining (ECM), stray corrosion always causes undesired material dissolution and deteriorates the machining localization. Adopting sidewall insulating films on the electrode is proven to be an effective approach for reducing stray corrosion. Sidewall films with characteristics of good insulation, thin thickness, and excellent durability are required. In previous work, we proposed

3D printing technique for microfluidics provides a rapid and cost-effective manufacturing method in one step without considering the complex three-dimensional structures. Because of the layer-by-layer printing process, the microchannel was characterized with rough surface while lacking research on it. Currently, the surface roughness of microchannels is improved mainly by etching (solvent vapor or

Flexible electronic devices consisting of sensors and interconnects integrated with a soft polymer platform are being considered for emerging applications such as smart clothing, soft robotics, conformal batteries, and biomonitoring decals. Fabrication processes for such devices can require that the polymer platform be subjected to temperatures up to 300 °C without a significant deterioration of its

Traditional fabrication techniques are not suitable for the manufacturing of three-dimensional micro-scale structures. In this work, we report on a modified self molding punch-less sheet forming technique allowing fabrication of initially curved, non-planar, shallow micro shells. These structures, when appropriately configured, may exhibit the coexistence of two equilibria under the same loading. A

A mathematical model of a high-sensitivity pressure sensor with a novel electrical circuit utilizing a piezosensitive transistor differential amplifier with negative feedback loop is presented. Circuits utilizing differential transistor amplifiers based on vertical n-p-n and lateral p-n-p transistors are analyzed and optimized for sensitivity to pressure and stability of output signal in operating

Flexible organic films with through-holes array count for many fields, such as flexible MEMS structures and electrochemical machining (ECM) masks. Polydimethylsiloxane (PDMS) is a material often used as flexible films due to the advantages of chemically inert, transparent, and well-combined with silicon-based materials. Generally, the flexible films with through-holes were fabricated by the pattering

As a refractory metal with a high melting temperature and large coefficient of thermal expansion, tantalum (Ta) is of great interest as a structural material in MEMS. One of the major issues with any freestanding structure, however, is the control of residual stress. Here, we observe that suspended fixed–fixed beams made from Ta films under tension buckle after a buffered hydrofluoric (BHF) acid release

This study analyses the transfer path of electrical feed-through noise in the electromechanical amplitude modulation detection circuit of a micro-electro-mechanical system vibrating gyroscope. By considering the feed-through, circuit and mechanical thermal noises, a new noise model in the force-to-rebalance closed-loop detection is constructed, and the expression of the noise-equivalent rotation rate

The macro-to-micro interface method presented here meets many of the requirements for an ideal interconnect by sealing a short length of plastic tubing directly to a microfluidic chip. The adaptability and low-temperature processing make it compatible with a wide range of device materials. The method was validated on silicon, acrylic (polymethyl methacrylate), printed circuit board and glass substrates

It has been a challenge to develop pressure sensors that can work in harsh environments. In this work, a piezoresistive n-type 4H-SiC pressure sensor is demonstrated, capable of working at 350 °C under hydraulic and pneumatic pressure. The pressure measuring range of this sensor is 7 MPa and the chip dimension is 2.5 mm × 2.5 mm × 0.23 mm. A reliable Ti/TaSi 2 /Pt metal ohmic contact is used in the

3D microlattices fabricated through multi-photon lithography have been widely utilized for photonics, bio-scaffolds and architected metamaterials. Post-processing techniques have accentuated the reduction of the overall size to the nanoscale and the modification of the material properties of these structures. However, there are no processing techniques that can locally modify the morphology and the

Suspended microfluidic resonators enable detection of fluid density and viscosity with high sensitivity. Here, a two-legged suspended microchannel resonator that probes pico-litres of liquid is presented. The higher resonant modes (flexural and torsional) were explored for increased sensitivity and resolution. Unlike other reported microchannel resonators, this device showed an increase in the quality

This study presents the design, fabrication and testing of the capacitive-type MEMS microphone with differential sensing electrodes to improve the sensitivity and signal-to-noise ratio (SNR). The microphone is designed and implemented based on an existing trench-refilled MOSBE process platform with two polysilicon structure layers, one Si 3 N 4 electrical isolation layer and two sacrificial SiO 2 layers

Sylgard TM 170 is usually utilized as a structural material for the functional surface in microstructure adhesion. Its mechanical properties and hyper-elastic constitutive equation are presented to lay a foundation for further construction of an accurate interface adhesion model and fiber structure optimization with better adhesion capacity. Through uniaxial tension experiments on the structural material

Micro Electro Mechanical Systems (MEMS) membranes are utilized as both transmitter and receiver in acoustic and ultrasound applications. Their operating frequency ranges are determined by their resonance frequencies. Thus, the resonance frequency estimation is one of the most critical parts of the membrane design. In this study, two perforated circular MEMS membranes are designed, microfabricated and

This paper presents a study of droplets generation, particularly examining different regimes or patterns of the flow by a novel device that combines two principles for droplets generation (flow focusing and T-junction (FF-TJ)) under different flow conditions, named combined FF-TJ. The study involves both experiment and simulation. From the experiment mineral oil and distilled water, three regimes (namely

Recent advances in MEMS technology have brought forward a new class of high-density stretchable/flexible electronics as well as large displacement MEMS devices. The in-situ electro-mechanical characterization of such devices is challenging since it requires: (i) highly delicate sample handling, (ii) controlled application of large (hundreds of µ m) multi-axial displacements to mimic service conditions

We present on-chip acoustic actuation of in situ fabricated artificial cilia. Arrays of cilia structures are UV polymerized inside a microfluidic channel using a photocurable polyethylene glycol (PEG) polymer solution and photomasks. During polymerization, cilia structures are attached to a silane treated glass surface inside the microchannel. Then, the cilia structures are actuated using acoustic

The high performance and small size of MEMS based scanners has allowed various optical imaging techniques to be realized in a small form factor. Many such devices are resonant scanners, and thus their linear and nonlinear dynamic behaviors have been studied in the past. Thin-film piezoelectric materials, in contrast, provide sufficient energy density to achieve both large static displacements and high-frequency

This paper reports an improved CMOS compatible low temperature sacrificial layer fabrication process for Capacitive Micromachined Ultrasonic Transducers (CMUTs). The process adds the fabrication step of silicon oxide evaporation which is followed by a lift-off step to define the membrane support area without a need for an extra mask. This simple addition improves reliability by reducing the electric

Electrothermal actuators have many advantages compared to other actuators used in Micro-Electro-Mechanical Systems (MEMS). They are simple to design, easy to fabricate and provide large displacements at low voltages. Low voltages enable less stringent passivation requirements for operation in liquid. Despite these advantages, thermal actuation is typically limited to a few kHz bandwidth when using

Bacterial separation from human blood samples can help with the identification of pathogenic bacteria for sepsis diagnosis. In this work, we report an acoustofluidic device for label-free bacterial separation from human blood samples. In particular, we exploit the acoustic radiation force generated from a tilted-angle standing surface acoustic wave (taSSAW) field to separate E. coli from human blood

Excellent chemical and physical properties of glass, over a range of operating conditions, make it a preferred material for chemical detection systems in analytical chemistry, biology, and the environmental sciences. However, it is often compromised with SU8, PDMS, or Parylene materials due to the sophisticated mask preparation requirements for wet etching of glass. Here, we report our efforts toward

In this paper, we reported a new approach for particle assembly with acoustic tweezer during three-dimensional (3D) printing for the fabrication of embedded conductive wire with 3D structures. A hexagon shaped acoustic tweezer was incorporated with Digital Light Processing (DLP) based stereolithography (SLA) printer to pattern conductive lines via aligning and condensing conductive nanoparticles. The

We present an acoustofluidic micromixer which can perform rapid and homogeneous mixing of highly viscous fluids in the presence of an acoustic field. In this device, two high-viscosity polyethylene glycol (PEG) solutions were co-injected into a three-inlet PDMS microchannel with the center inlet containing a constant stream of nitrogen flow which forms bubbles in the device. When these bubbles were

The ability to control nonlinear interactions of suspended mechanical structures offers a unique opportunity to engineer rich dynamical behavior that extends the dynamic range and ultimate device sensitivity. We demonstrate a displacement sensing technique based on resonant frequency monitoring of curved, doubly clamped, bistable micromechanical beams interacting with a movable electrode. In this configuration

Cell migration is one of the crucial steps in many physiological and pathological processes, including cancer development. Our recent studies have shown that carbon nanotubes (CNTs), similarly to asbestos, can induce accelerated cell growth and invasiveness that contribute to their mesothelioma pathogenicity. Malignant mesothelioma is a very aggressive tumor that develops from cells of the mesothelium

We report on a microfluidic mixer fabrication platform that increases the versatility and flexibility of mixers for biomolecular applications. A sandwich-format design allows the application of multiple spectroscopic probes to the same mixer. A polymer spacer is 'sandwiched' between two transparent windows, creating a closed microfluidic system. The channels of the mixer are defined by regions in the

Mixing in microfluidic devices presents a challenge due to laminar flows in microchannels, which result from low Reynolds numbers determined by the channel's hydraulic diameter, flow velocity, and solution's kinetic viscosity. To address this challenge, novel methods of mixing enhancement within microfluidic devices have been explored for a variety of applications. Passive mixing methods have been

The use of flexible micro-electro-mechanical systems (MEMS) based device provides a unique opportunity in bio-medical robotics such as characterization of normal and malignant tissues. This paper reports on design and development of a flexible MEMS-based sensor array integrating mechanical and electrical sensors on the same platform to enable the study of the change in electro-mechanical properties

We present a new fabrication method to produce arrays of highly responsive polymer-metal core-shell magnetic microactuators. The core-shell fabrication method decouples the elastic and magnetic structural components such that the actuator response can be optimized by adjusting the core-shell geometry. Our microstructures are 10 μm long, 550 nm in diameter, and electrochemically fabricated in particle

Microscopic droplets or slugs of mixed reagents provide a convenient platform for performing large numbers of isolated biochemical or chemical reactions for many screening and optimization applications. Myriad microfluidic approaches have emerged for creating droplets or slugs with controllable size and composition, generally using an immiscible carrier fluid to assist with the formation or merging

Tuberculosis (TB) has been a major public health problem, which can be better controlled by using accurate and rapid diagnosis in low-resource settings. A simple, portable, and sensitive detection method is required for point-of-care (POC) settings. This paper studies an amperometric biosensor using a microtip immunoassay for a rapid and low cost detection of Mycobacterium Tuberculosis (MTB) in sputum

Time-resolved cryo electron microscopy (TRCEM) has emerged as a powerful technique for transient structural characterization of isolated biomacromolecular complexes in their native state within the time scale of seconds to milliseconds. For TRCEM sample preparation, microfluidic device [9] has been demonstrated to be a promising approach to facilitate TRCEM biological sample preparation. It is capable

A novel three degree-of-freedom microactuator based on thin-film lead-zirconate-titanate (PZT) is described with its detailed structural model. Its central rectangular-shaped mirror platform, also referred to as the stage, is actuated by four symmetric PZT bending legs such that each leg provides vertical translation for one corner of the stage. It has been developed to support real-time in vivo vertical

Singulation of MEMS is a critical step in the transition from wafer-level to die-level devices. As is the case for capacitive micromachined ultrasound transducer (CMUT) ring arrays, an ideal singulation must protect the fragile membranes from the processing environment while maintaining a ring array geometry. The singulation process presented in this paper involves bonding a trench-patterned CMUT wafer