Microheater

About: Microheater is a research topic. Over the lifetime, 814 publications have been published within this topic receiving 12478 citations.

MEMS based metal oxide semiconductor carbon dioxide gas sensor

Abstract: This paper describes the design and development of low power Micro Electro Mechanical Systems (MEMS) microheater and metal oxide semiconductor CO2 sensor. To achieve low power, suspended plasma enhanced chemical vapour deposited SiO2 diaphragm is used. BaTiO3-CuO is considered as metal oxide doped with 1% Ag and will be used as a sensing material to sense the CO2 gas. To get the required temperature for the sensing film, three different metals namely, Platinum (Pt), Titanium (Ti) and Tungsten (W) are simulated by using COMSOL Multiphysics 5.6. The proposed microheater structure is shown to have a good temperature consistency throughout the heater's active region while consuming low power. The microheater geometry of 100 μm × 100 μm with its electro-thermal temperature results is presented here. For an applied voltage, we report a maximum average temperature of Pt i.e. ∼99.51%, Ti ∼ 97.12% and W ∼ 89.78% for 300 °C respectively. Fabrication of CO2 sensor along with MEMS microheater had been designed and demonstrated. Energy consumed by the proposed platinum microheater geometry is 4.8 mW at 250 °C and 5.8 mW at 300 °C. The sensitivity characteristic is based on resistance sensing which has been found to be 21% for 400 ppm CO2 gas concentration and 70% for 1000 ppm. Comparatively capacitive based sensitivity is found to be ~54% for 400 ppm and 95% for 1000 ppm.

New type thin film vacuum sensor using the short circuit seebeck-current detection type thermocouple

Abstract: We have proposed the thin film vacuum sensor that has a cantilever structure with new temperature difference sensors of the short circuit Seebeck-current detection type thermocouple in order to get higher sensitivity in the higher vacuum range. Temperature difference, which should be zero under the higher vacuum, between microheater and thermally isolated heading area from the microheater is measured under the vacuum pressure. Even a little temperature difference in our new sensor can be measured in very lower vacuum pressure range by the signal amplification than that of the traditional Pirani vacuum sensor. In our experiments, the short circuit Seebeck-current detection type thermocouple is used to measure the very small temperature difference. Measurement of very wide vacuum pressure range between 105 - 10-2 Pa is achieved by the prototype sensor.

열민감성 공액고분자를 이용한 미세유동칩 내의 온도 측정

Abstract: Microfluidic chips have been frequently utilized to perform biochemical analysis, like cell culture, cell-based drug screening, biomolecule synthesis, and etc, because they reduce the consumptions of analytes and reagents and automate multi-step analysis processes. It is often critical to monitor temperature in a microchannel for the analysis in order to control a reaction rate of biomolecules. We propose a novel method to monitor a temperature change in a microchannel flow by using polydiacetylene (PDA), a conjugated polymer, that has a unique property to transform its color from visible blue to fluorescent red by thermal stress. We inject PDA sensors of the form of a droplet into the microchannel with a microheater on the bottom. Preliminary results show that the florescence intensity of a PDA sensor droplets varies with the temperature.

Formation and observation of thermal bubble from multilayer heating material

Abstract: The target of this research is to design and fabricate the micro-heater and its electrodes in order to study the thermal bubble behavior. In fabrication of micro-heater, this research focus on the design of multilayer micro-heater and the selection of materials further. For the multilayer materials, we choose Ti/Al/Ta (15/25/200 nm/nm/nm) to be the material to replace the conventional polysilicon, Ta or expensive Pt heaters for improving the heat-resistant ability of Pt, poor adhesion of Ta and high electrical resistance of polysilicon. Then, the bubble sizes between frequencies and voltages were discussed in the multilayer heating materials. The multilayer micro-heater in this research can generate good bubbles at low frequencies operation. It has the advantages of low electrical resistance, the good thermal resistance, and the good heat dissipation to contribute to improve the poor heat dissipation and strength of the Pt micro-heater in order to increase the life of the heater.

Application of a fluorescent dye-based microfluidic sensor for real-time detection of mAb aggregates.

Abstract: The lack of process analytical technologies able to provide real-time information and process control over a biopharmaceutical process has long impaired the transition to continuous biomanufacturing. For the monoclonal antibody (mAb) production, aggregate formation is a major critical quality attribute (CQA) with several known process parameters (i.e., protein concentration and agitation) influencing this phenomenon. The development of a real-time tool to monitor aggregate formation is then crucial to gain control and achieve a continuous processing. Due to an inherent short operation time, miniaturized biosensors placed after each step can be a powerful solution. In this work, the development of a fluorescent dye-based microfluidic sensor for fast at-line PAT is described, using fluorescent dyes to examine possible mAb size differences. A zigzag microchannel, which provides 90% of mixing efficiency under 30 s, coupled to an UV-Vis detector, and using four FDs, was studied and validated. With different generated mAb aggregation samples, the FDs Bis-ANS and CCVJ were able to robustly detect from, at least, 2.5% to 10% of aggregation. The proposed FD-based micromixer is then ultimately implemented and validated in a lab-scale purification system, demonstrating the potential of a miniaturized biosensor to speed up CQAs measurement in a continuous process.