Development of ball surface acoustic wave gas chromatograph for environmental monitoring in spacecraft and its application on the ground

Abstract

For on-site analysis of surface materials on the moon, planets, and small bodies and for the monitoring of air quality in crewed spacecraft, we have developed a portable gas chromatograph (GC) equipped with a ball surface acoustic wave (SAW) sensor. In this study, we fabricated a 10 cm cube GC that implements the forward flush method using two metal micro-electro-mechanical-system (MEMS) columns coated with different stationary phases in microchannels fabricated by wet etching and diffusion bonding of stainless-steel plates. Using this GC, we succeeded in analyzing 10 kinds of gas within 10 min. In addition, for the application of the ball SAW GC on the ground, we also developed a palm-sized GC with a single metal capillary column and used it in the analysis of the headspace gas of sake. We showed that the ratio of peak areas differed among odorants depending on the brand and brewing process of sake.

Ultrasensitive wireless quartz crystal microbalance bio/gas sensors

“…Furthermore, the α value [Eq. (10)] is also unaffected by the impurity, indicating that the ultrahighfrequency QCM measurement retains the advantages of a label-free biosensor even in a large amount of contaminants.…”

“…Its crystallographic symmetry belongs to the 32-point group (trigonal system), exhibiting six independent elastic constants, two independent piezoelectric constants, and two independent dielectric constants. Thanks to these important properties, quartz has been used as a substrate in many resonators for communication devices, [1][2][3] biosensors, [4][5][6] gas sensors, [7][8][9][10] viscosity sensors, [11][12][13] and stress sensors. 14) AT-cut quartz resonators have been most commonly used for sensing applications because their through-thickness shear-resonance frequency shows extremely high temperature stability near RT.…”

Analysis of longitudinal leaky surface acoustic waves on piezoelectric thin plates bonded to diamond substrate

“…The research and development of SAW propagation modes and piezoelectric materials for high-performance SAW devices have been actively conducted in Japan and overseas. [1][2][3][4][5][6][7][8][9][10][11][12][13] In particular, 5 GHz bands, called the Sub-6 band in 5G communication systems, are approximately 1.5-2 times higher than those of 4G communication systems. Hence, there is a significant demand for higher frequencies in SAW filters.…”

High speed measurement of liquid properties from behavior of micro droplets on vertically oscillating substrate

“…The phenomenon shown in Fig. 4 is a typical nonequilibrium and non-steady phenomenon, which is one of the frontier topics 23,24) in statistical physics. The results of this experiment showed the possibility of using micro liquid droplets as tools and devices to observe these high-speed and fragile nonequilibrium phenomena occurring on the surface of soft materials.…”