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Fuel cells will be applied extensively in the future as renewable energy sources, explaining why a considerable amount of research has addressed this topic. However, among the various problems encountered in the mass production of fuel cells that have yet to be solved include those associated with the bipolar plate, flow channel, catalyst, membrane electrode assembly (MEA), gas diffusion layer (GDL)...
We present a detailed analysis of thermal mismatch stress (TMS) [1] developed in composite beams built on compliant sacrificial layer (SAC) [2]. Strikingly, the stress-balance of beams is strongly affected by the SAC compliance, which is substantiated by comparison of analytic models, finite element analysis (FEA), and measurements. With this analysis we concluded that the highly compliant organic...
This paper presents a microfabricated 2 times 3 array oxygen sensor integrated with heaters and temperature sensors for measuring cellular respiration level in a solution containing cells. The proposed oxygen sensor consists of 2 times 3 array Clark-type sensors, heaters, and temperature sensors on the substrate. Pt was used for temperature sensors, working electrode and counter electrode of Clark-type...
We present an advantageous fabrication technology for the integration of pressure sensor into the multi-sensor for micro weather station. Differing from traditional silicon piezoresistive or capacitive pressure sensor, we use platinum piezoresistive pressure sensor in the integration, which can greatly simplify the whole process and also has an excellent performance. We also use adhesive bonding with...
A micro flow sensor with high temperature coefficient of resistance (TCR) is very important because of its high sensitivity of flow sensors. Different from the conventional positive-TCR Pt film used in micro flow sensor with self-heating, higher negative-TCR micro flow sensor without self-heating is developed and fabricated in this research. The novel TaN-material micro liquid flow sensors are fabricated...
Bovine pancreatic trypsin conjugates were first synthesized using succinoylated beta-cyclodextrin and succinoylated PAMAM dendrimer. Their conjugates had a trypsin content of 72 and 50 wt%, respectively. The trypsin activity of conjugates measured by using Nalpha-benzoyl-D, L-arginine-p-nitroanilide hydrochloride (BAPNA) as substrate was decreased by polymer conjugation. The kinetic parameters (KM...
The production of useable energy is today a global issue and the search for alternative energy sources is very challenging. Therefore, scientists have' tried hard to identify new alternative energy sources. Fuel cells have potential as an indispensable source of electrical power. However, the mass production of fuel cells encounters various problems, which are yet to be solved, such as determining...
Features of the I-V characteristics and the electrical properties of electronics-grade carbon nanotube (EG-CNT) sensors, which were fabricated and integrated in micro fluidic system by combining MEMS-compatible fabrication technology with AC dielectrophoresis technique, were investigated at room temperature to account for significant Joule heating effect under high activation current. The experimental...
In order to solve the pressure measurement problem in the harsh environment, such as high temperature above 200degC, a special piezoresistive pressure sensor chip has been developed. Based on the MEMS (micro electro-mechanical system) and SIMOX (separation by implantation of oxygen) technology, the piezoresistive pressure sensor chip was constituted by silicon substrate, a thin buried silicon dioxide...
Among those problems regarding use of micro reformers that have not yet been solved include reducing their size, decreasing the amount of CO and combining the fuel cell, among others. Therefore, in this work, a micro temperature sensor and a heater are combined inside a stainless steel-based micro reformer to measure the temperature, to improve performance and minimize the concentration of CO. Micro-electro-mechanical-systems...
Microelectromechanical system (MEMS) convective accelerometer based on convection heat transfer has many advantages such as simple structure, low cost and great anti-shock property. Due to its great anti-shock property, we research the output characteristics of the convective accelerometer with low measuring range (plusmn5 g) (g stands for acceleration of gravity) when the input is heavy impact (500~30,000...
An electromagnetically excited silicon nitride beam resonant pressure sensor is described and numerical modeling is carried out on the analysis of the sensitivity of pressure measurement and temperature drift. The proposed approach is based on measurement of resonant frequencies for two resonant beams located on a diaphragm inducing different axial stress under an applied pressure, the differential...
In this paper, a highly sensitive temperature sensor based on quartz tuning fork resonators is reported. The temperature sensor is configured by ZY (110deg/10deg) Cut quartz crystal wafer based bulk acoustic wave (BAW) tuning fork resonators whose operating frequency is at 31 KHz. The ideal thermo-sensitive ZY cut for quartz tuning fork resonators is analyzed with the theory. The characterization...
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