The aim of this study was to explore new valid sensors for temperature biofeedback. Three kinds of temperature sensors (thermography imaging, thermistor, and infrared thermopile) were employed to record participants’ finger surface temperatures simultaneously. The skin temperature readings resulted in strong correlations between sensors. These results suggested that contact and non-contact temperature sensors all had good synchronous temperature covariance in measuring finger surface temperature.
Three-dimensional molecular dynamics (MD) simulations of nanojet ejection with different aperture shapes are reported. The simulations use the Lennard-Jones 12-6 (LJ) potential to describe the intermolecular interaction. Using non-equilibrium MD, argon nanojet ejection is simulated under vacuum conditions. According to the analysis, different aperture shapes influence the ejection processes. The ejection speeds were 23.7 and 63.2 m/s respectively in the simulation. The speed of spurting atoms in type A nanojet was slower than the other types and it became more obvious when the process time increased. The variations in velocity, density, pressure, and temperature were found with the aid of MD. The liquid temperatures were set at 50, 100, 150, and 200 K, respectively, to examine nanojet break-up characteristics. The liquid temperature inside the nanojet was found to be a factor that induce break-up. A higher temperature led to faster nanojet break-up.
Due to aggravating competition and living pressure in modern societies, stress syndrome worsens, and somatic dysfunctions or pathological changes arise more obviously and frequently than before. For stress management, physiological feedback or muscle relaxation with physiological feedback monitoring is useful in alleviating stress syndrome and improving mental health. Physiological feedback has been recognized as one of the main treatment modes in behavior therapy, and is widely adopted in clinical practices to date. Among all measures, temperature feedback is most employed by therapists. However, devices suitable for mobile use and daily monitoring, which are critical to training of stress management, are absent. To fulfill such need, a portable temperature feedback apparatus is developed, which is in form of a ring and an innovative design. In this paper, the product design process is addressed as an interdisciplinary approach for new product development and a case study for design integration. Signal analysis and usability test are held to verify functionalities of the ring device. As a result, a new treatment approach integrating the ring device and its concerned systems into group therapy is proposed. With the new design, stress management becomes more viable and distant treatment more feasible.
In this work, the electroless plated (EP) Pd/InGaP high electron mobility transistor (HEMT) was firstly employed for hydrogen sensing. The current-voltage (I-V) characteristics under hydrogen concentrations of 5ppm-1% and temperatures of 303-503K were investigated. Experimentally, the Pd gate of three-terminal devices were successfully fabricated by the electroless plating method, and the studied devices exhibited excellent current-voltage characteristics with superior current control ability. For hydrogen sensing performances, the studied EP device demonstrated low detection limit, high sensitivity, and fast response. As compared with the thermal evaporated (TE) device, larger current variations can be achieved by the EP device. Even at extremely low hydrogen concentration, e.g., 4.3 ppm H 2 /air, obvious current modulation was found. The maximum relative sensitivity reaches up to 428 % at a optimal gate voltage of -0.75 V. Furthermore, the transient detections showed that the sensing response was fairly fast, especially at high concentrations and high temperatures. At detection temperature of 403 K, the time for 90% response at 1 % H 2 /air was within 4 seconds. These excellent sensing performances of the EP device indeed made it promising and competitive in future developments of smart hydrogen sensors integrated microelectronic systems.
Photonic crystals, which are the artificial multidimensional periodic structures, are attractive for ultra-compact optoelectronic devices. Various photonic crystals devices based on their photonic bandgap (PBG) have been reported. Recently, several methods have been developed for fabricating three-dimensional (3D) photonic crystals. One of the simple methods is using colloidal spheres such as polystyrene or silica beads to form 3D face-centered cubic crystalline structures. An important issue for colloidal spheres based PBG devices is how to fabricate the devices with small bandgap-shift for optoelectronic device applications. In general, it is difficult to tune the size of colloidal spheres continuously expecting for controlling the strict synthesis conditions [1, 2].Generally the colloidal spheres based PBG structures are formed by the monodispersed silica or polystyrene beads, and their bandgaps are decided by the refractive index and diameter of beads. In this paper, we demonstrate a simple method that can control the bandgap position by utilizing hybrid polymer and silica beads with large size-difference. The polystyrene (PS) beads with 750nm diameter and silica beads with 50nm diameter are mixed to form different PBG structures. Figure 1 shows the SEM images of crystalline opal structures constructed by polystyrene beads with and without silica beads. We found that the polystyrene beads were separated by silica beads with 50 nm distance. As shown in Figure 2, the transmittance dips (bandgap) of opal structures were shifted continuously from 1730nm to 1800nm as increasing the silica colloid concentrations. The bandgap-shift percentages are also increased from 0.5 % to 3.75 %. Moreover, we can study the effect of the distribution of silica beads among the polystyrene beads. The polystyrene beads are separated by 50nm and hence the atomic packing factor (APF) degrades from 74% to 61%. Figure 3 (a) and 3 (b) show the interstitial between separated polystyrene beads are filled with air hole and closed-packed silica beads, respectively. According to the Bragg law, the band-gap is shift to long wavelength with 1.708% for separating by air hole as shown in Table I. Similarly if the interstitial between separated polystyrene beads is filled with closed-packed silica beads. The band-gap will shift to long wavelength about 10.27% as shown in Table I. Comparing with our experimental results, we can propose that the content of silica beads of 1Op1I and 20,1, the PS beads nearly maintains close-packed, but only a few silica beads locate in the interstitial of the PS beads. As the content of silica beads increased to 3Opl, 40p1 and 50p1, the probability of silica beads filled in the gap of polystyrene beads is increased, and the bandgap is shifted to longer wavelength. Detailed analysis will be reported in the conference. References 1.
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