Microheater

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

Thermal sensors based on nano porous silicon

Abstract: In this study, the thermal properties of silicon samples with surfaces of porous and geometrical formation were reported. The etching methods of anodization chemical and heated KOH were utilized to perform the studied nano porous silicon (NPS) and pyramidal, respectively. Compared with usual surface formation of ordinary silicon sample, the larger surface to volume ratios were obtained from the fabricated NPS and pyramidal silicon devices. For the thermal applications such as thermal sensor and microheater, the etching profiles and surface to volume ration of studied were clarified by SEM measurement. Furthermore, the differential scanning calorimetry (DSC) was used to evaluate the thermal dissipation properties of studied samples.

Dusty plasmas for on-site spectroscopic analysis of water sources

Abstract: This paper reports on a low-cost, borosilicate glass-based spectroscopic sensor for the detection of water contaminants. 10 P L water samples are inserted into a sandblasted sample re servoir in a borosilicate glass substrate and are partially evaporated with a 200 nm thin-film Cr microheater/cathode patterned to the bottom of the reservoir. The relative contaminant concentration within the partially evaporated sample is greater, providing a means of measuring lower concentrations of impurities. An on-chip plasma discharge is stuck to the sample, sputtering the water contaminants into the discharge, doping its spectral emissions. Cu and Fe impurities are detected at 10 ppm in a 2.5% HNO 3 solution and Ca and Mg contaminants are detected at 100 ppm. The on-chip microheater yields temperature changes as high as 96 qC when supplied with 100 mA. Multiple single-use sensors can be fabricated inexpensively on the borosilicate glass substrate using simple, standard photolithography techniques. Keywords: plasma spectroscopy, atomic emission spectroscopy, on-site water monitoring, metal ion water contaminants, metal ion water impurities, field-portable devices

Bulk Micromachined Electrothermal Hydraulic Microactuator and Its Applications

Abstract: Paraffin wax exhibits a volumetric expansion of ~15%, at around its melting point. By exploiting this expansion, electrothermal hydraulic microactuators have been demonstrated. The paraffin wax is contained within a bulk micromachined silicon container. The container is sealed using a PDMS diaphragm. The paraffin wax in the container is melted by a gold microheater on a glass substrate. All the layers used to make up the containers are bonded together using an overglaze and PDMS. Four applications of the microactuator have been demonstrated. The realization of a prototype refreshable Braille cell (3times2 dot, 7times8.5times2 mm 3 ) is presented. Other applications are microvalves and micropipettes for microfluidics, and the two types of microgrippers. All the devices have been successfully demonstrated and operate at either 10 or 15 V DC.

Analysis of Heat Flow for In Vitro Culture Monitored by Impedance Measurement

Abstract: The paper proposes an innovative method of using microheaters for research on cells in vitro. A method of local heating of a single culture well, compatible with an Electric Cell-substrate Impedance (ECIS) system is presented. A microheater and culture well system for cell culture was modelled. Electrical and thermal simulation of the system under operating conditions was carried out. Correct distribution of heat was observed at the site of the cell culture suspension in the medium, while not affecting the conditions in adjacent wells. As part of the experiment, a heating element of nichrome (NiCr) was created using the magnetron sputtering process. Electrical and thermal measurements of the manufactured device were carried out. It has been shown that it is possible to establish the desired temperature over the long term. In addition, the structures made were characterised by work stability, precision in maintaining the right temperature, and the possibility of being controlled with high accuracy. There is a problem with the precise and reproducible carrying out of a cell culture experiment that differs only in the process temperature. In this work, a technique for increasing the temperature locally, in a single culture well, in a medium containing eight such wells was proposed and analyzed. The use of this method will allow avoidance of the impact of potential changes in parameters other than temperature on the culture. That may occur when comparing cells grown at different temperatures by means of the ECIS (Electric Cell-substrate Impedance) method.

Experimental Validation of High Spatial Resolution of Two-Color Optical Fiber Pyrometer

Abstract: Taking non-contact temperature measurements in narrow areas or confined spaces of non-uniform surfaces requires high spatial resolution and independence of emissivity uncertainties that conventional cameras can hardly provide. Two-color optical fiber (OF) pyrometers based on standard single-mode (SMF) and multi-mode optical fibers (MMF) with a small core diameter and low numerical aperture in combination with associated commercially available components can provide a spatial resolution in the micrometer range, independent of the material’s emissivity. Our experiment involved using a patterned microheater to generate temperatures of approximately 340 °C on objects with a diameter of 0.25 mm. We measured these temperatures using two-color optical fiber pyrometers at a 1 kHz sampling rate, which were linearized in the range of 250 to 500 °C. We compared the results with those obtained using an industrial infrared camera. The tests show the potential of our technique for quickly measuring temperature gradients in small areas, independent of emissivity, such as in microthermography. We also report simulations and experiments, showing that the optical power gathered via each channel of the SMF and MMF pyrometers from hot objects of 250 µm is independent of distance until the OF light spot becomes larger than the diameter of the object at 0.9 mm and 0.4 mm, respectively.