Increasing numbers of companies are hosting multiple-stage student contests to solicit creative ideas and solutions, develop new products and services, and/or to address corporate issues. However, ...research on this topic to date has been limited to how to design multiple-stage student contests and motivate contestants to make novel and creative contributions. This study utilizes job design and motivation theories to develop a framework that positions student engagement as a key determinant of creativity. In all, 466 valid questionnaires were collected and analyzed using structural equation modeling. The results showed that contest designs and intrinsic motivation have a positive impact on student engagement. Extrinsic motivation has a nonsignificant effect on engagement. Intrinsic motivation and student engagement have a significant effect on creativity. These findings suggest that the design of crowdsourcing contests should focus on rapid feedback and autonomy. Furthermore, contests must include learning opportunities for students in the process.
•Contests characteristics, including competitor autonomy and feedback, were found to sustain engagement in contests.•Intrinsic motivation is vital to enhancing engagement and creativity.•Business offer a training course for student contests because engagement was found to be positively related to learning.
Stability in simulated gastric fluid is regarded as an important parameter for the estimation of food allergenicity. In this study, the digestive stability of allergenic protein tropomyosin (TM) and ...other food proteins from mud crab in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) digestion assay system was investigated and compared by SDS–PAGE and Western blot. In SGF system, proteins such as actin and the original band of myosin heavy chain (MHC) were rapidly degraded within a short period of time, while TM was relatively resistant to pepsin digestion. In SIF system, MHC was easily decomposed, while TM and actin were similarly resistant to digestion. Further study by IgE-immunoblotting and inhibition ELISA using sera from crab-allergic patients indicated that allergenicity of TM was partially decreased, suggesting proteinase digestion is effective in reducing the allergenicity of crab TM.
TiO 2 nanowires with rutile structures on a SiO 2 /Si substrate were grown by thermal evaporation. A field-emission property of the low turn-on field was reduced to 3.5 and 2.6 V/μm under UVA in 10 ...min and UVC in 25 min. The wavelength of UVC was higher than the TiO 2 band-gap, so the electrons more easily tunneled to the vacuum level and generated excess heat that lowered the turn-on field emission from under UVA. The work function of samples that had been exposed to UVA for 10 min and UVC for 25 min were reduced to 3.10 and 2.02 eV, respectively.
GaN-based metal-semiconductor-metal photodetectors (PDs) with a β-Ga 2 O 3 layer were fabricated. To increase performance, the Ga 2 O 3 /GaN-based PDs were covered with Au nanoparticles. The reverse ...leakage current decreased by more than two orders of magnitude with a 10-V applied bias and a 95-fold increase of the rejection ratio (250/360 nm) was achieved with a 1-V applied bias after the PDs were covered with Au nanoparticles. There was an obvious response at 490 nm because of the surface plasmon resonance in Au nanoparticles. The results indicate that Au nanoparticles can be used to improve the performance of optoelectronic devices.
We report the growth of β-Ga 2 O 3 nanowires using a vapor phase transport method and the fabrication of β-Ga 2 O 3 nanowire gas sensor. The β-Ga 2 O 3 nanowire sensor shows reversible response to ...isopropyl alcohol (IPA) gas at temperature as low as 100 °C. With 300 ppm IPA gas introduced, it was found that measured responses were ~ 7.5%, 13.5%, and 23% when the sensor was operated at 100 °C, 200 °C, and 300 ° C, respectively. It was also found that the responses measured at 300 °C were ~ 9%, 15.5%, 24%, and 33% when the injected IPA gas concentrations were 100, 200, 300, and 400 ppm, respectively.
We report the growth of β-Ga 2 O 3 nanowires (NWs) on GaN substrate and the fabrication of β-Ga 2 O 3 NW humidity sensors. It was found that average length and diameter were ~10 μm and 100 nm, ...respectively. It was also found that the current of the NWs increased as we increased the relative humidity because of the n-type nature of β-Ga 2 O 3 . Through measuring current-voltage characteristics of the fabricated device at 25 °C, it was found that the measured currents were 5.99×10 -5 , 6.42×10 -5 , 6.76×10 -5 , 7.33×10 -5 , and 7.93×10 -5 A when measured with 35%, 50%, 65%, 85%, and 95%-relative humidity, respectively.
β-Ga 2 O 3 /AlGaN/GaN heterostructure three-band photodetectors (PDs) are fabricated and operated in ultraviolet (UV)-A, UV-B, and UV-C regions. The operation mode of the device can be switched by ...changing the applied bias and the thickness of the thin films. The UV-C to UV-B and UV-B to UV-A contrast ratios of the PD with a -1 V applied bias are 14.4 and 2157.9, respectively. The UV-A to visible contrast ratio of the PD with a -10 V applied bias is 247.9.
The growth of ZnO nanowires (NWs) on a zinc oxide (ZnO)/textured crystalline-Si (c-Si) photovoltaic device via the hydrothermal method is investigated. The average length and diameter of the ZnO NWs ...are around 0.65μm and 70–100nm, respectively. Experimental results indicate that a ZnO/textured c-Si photovoltaic device with ZnO NWs has the lowest reflectance among the tested substrates, especially in the range of ultraviolet (UV) and green light (350nm to 590nm). Compared to SiNx/textured c-Si and ZnO/textured c-Si photovoltaic devices, the proposed device exhibits photovoltaic conversion efficiency improvements of around 7% and 6.3%, respectively. After encapsulation, the ZnO NWs/ZnO/textured c-Si photovoltaic device has the lowest drop in conversion efficiency. Furthermore, a small NW diameter increases light absorption.
The authors present the fabrication of a TiO 2 nanowire ultraviolet (UV) photodetector (PD) with Iridium Schottky contact electrodes. UV-to-visible rejection ratio of the sample is around 107 when ...biased at 5 V, and the fabricated PD is visible-blind with a sharp cutoff at 390 nm. With an incident light wavelength of 390 nm and an applied bias of 5 V, the measured responsivity of the PD is 9.73 × 10 -4 A/W.
The authors report the growth of TiO 2 nanowires by heating the Ti/glass template and the fabrication of a TiO 2 nanowire metal-insulator-semiconductor (MIS) photodetector (PD). Compared with a TiO 2 ...nanowire metal-semiconductor- metal PD, it was found that we could achieve a photocurrent 29 times larger. It was also found that the dynamic response of the TiO 2 nanowire MIS PD was stable and reproducible with an on/off current contrast ratio of around 180. With an incident light wavelength of 390 nm and an applied bias of 5 V, it was found that the measured responsivity of the PD was 2.46 × 10 -3 A/W. Furthermore, the noise equivalent power and the detectivity of the fabricated TiO 2 nanowire MIS PD were 7.49 × 10 -12 W and 8.86 × 10 11 cm · Hz 0.5 · W -1 , respectively.
