5 ?ConclusionsIn this paper, we have described an optical gas lea

5.?ConclusionsIn this paper, we have described an optical gas leak sensor based on IR spectroscopy for detecting ethylene, dimethyl ether, and methane. The system was developed to prevent gas accidents in the processes of hazardous chemicals production, storage, transport, etc. Optical gas detection is superior to traditional detection methods in terms of accuracy, speed, and even security. Conventional devices for optical gas detection include a broadband source, a rotating chopper shutter, a narrow-band filter, a sample tube, and a detector. The sensor uses a miniature dual-channel detector, an electrical modulation source, and a miniature gas cell structure. The system is thus small, low-powered, and portable. The system has no moving parts, and is reliable and durable because of no chopper or mechanical modulators are required.

By replacing the filter, we can also detect gases with different infrared absorption peaks, allowing for multi-gas detection with a single unit. Therefore, this sensor has a variety of potential industrial and military applications.AcknowledgmentsThis work was supported by National Science Fund for Distinguished Young Scholars (51205373). This work also received support from the Basic Research Projects Shanxi Province (2012021013-4).
The temperature control of microfluidic channels is essential for lab-on-a-chip experiments, such as capillary electrophoresis [1]. The temperature in these microfluidic channels is typically measured by imaging temperature-sensitive materials dissolved in liquids.

This method enables the wireless sensing of remote temperatures and is thus highly applicable to measuring the temperatures of small fluidic channels. Fluorescent dyes (or thermochromic liquid crystals), and more recently quantum dots, have been used as temperature-sensitive materials because their photoemission intensities are temperature dependent [2�C 8]. This method is versatile, but also possesses several drawbacks. First, the method is sensitive to changes in the material concentration, which causes fluctuations in the photoemission intensity, resulting in inaccurate temperature measurements. Second, the material typically becomes contaminated in the solution, which can hinder the chemical reaction in the microchannel. Thus, it is desirable to develop a method in which the material does not interact with the chemicals in the solution.

In this paper, we develop AV-951 a temperature sensor using fluorescent dye droplets that are encapsulated by an impermeable polymer thin film. Our group previously developed a method to vacuum seal nonvolatile liquids using a Parylene coating, which is known as PoLD (Parylene on liquid deposition) [9,10]. Two fluorescent dyes were dissolved in a nonvolatile ionic liquid to enable ratiometric temperature measurements.

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