Effect of Same-Temperature GaN Cap Layer on the InGaN/GaN Multiquantum Well of Green Light-Emitting Diode on Silicon Substrate

GaN green LED was grown on Si (111) substrate by MOCVD. To enhance the quality of InGaN/GaN MQWs, same-temperature (ST) GaN protection layers with different thickness of 8 Å, 15 Å, and 30 Å were induced after the InGaN quantum wells (QWs) layer. Results show that a relative thicker cap layer is benefit to get InGaN QWs with higher In percent at fixed well temperature and obtain better QW/QB interface. As the cap thickness increases, the indium distribution becomes homogeneous as verified by fluorescence microscope (FLM). The interface of MQWs turns to be abrupt from XRD analysis. The intensity of photoluminescence (PL) spectrum is increased and the FWHM becomes narrow

Handwriting velcro: Endowing AR glasses with personalized and posture-adaptive text input using flexible touch sensor

Text input is a desired feature for AR glasses. While there already exist various input modalities (e.g., voice, mid-air gesture), the diverse demands required by different input scenarios can hardly be met by the small number of fixed input postures offered by existing solutions. In this paper, we present Handwriting Velcro, a novel text input solution for AR glasses based on flexible touch sensors. The distinct advantage of our system is that it can easily stick to different body parts, thus endowing AR glasses with posture-adaptive handwriting input. We explored the design space of on-body device positions and identified the best interaction positions for various user postures. To flatten users' learning curves, we adapt our device to the established writing habits of different users by training a 36-character (i.e., A-Z, 0-9) recognition neural network in a human-in-the-loop manner. Such a personalization attempt ultimately achieves a low error rate of 0.005 on average for users with different writing styles. Subjective feedback shows that our solution has a good performance in system practicability and social acceptance. Empirically, we conducted a heuristic study to explore and identify the best interaction Position-Posture Correlation. Experimental results show that our Handwriting Velcro excels similar work [6] and commercial product in both practicality (12.3 WPM) and user-friendliness in different contexts

Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

Heaping in Reported Earnings: Evidence from Monthly Financial Reports of Taiwanese Firms

Heaping is a phenomenon in which reported numbers tend to appear in increments that are important for cultural or other reasons. This study reports that heaping is present in monthly earnings reports for publicly listed companies in Taiwan. We find that Taiwanese firms tend to report monthly earnings in increments of 5 in the first two places (digits) of the earnings numbers. Furthermore, we observe predominantly more zeros in the third through fifth places of monthly earnings numbers, suggesting that monthly earnings tend to be reported in increments of 10 in the first three, first four, and first five places. Reporting of monthly earnings in Taiwan is discretionary, and our findings suggest that managers of Taiwanese firms are susceptible to heuristic bias when reporting monthly earnings. These findings complement studies on heaping in U.S. financial markets documenting that managers and financial analysts tend to make earnings per share estimates that heap in increments of nickels.Benford's law, cognitive bias, heaping, voluntary disclosure,

Molecular Dynamics Study on the Spontaneous Adsorption of Aromatic Carboxylic Acids to Methane Hydrate Surfaces: Implications for Hydrate Antiagglomeration

Spontaneous adsorption of aromatic carboxylic acids (phenylacetic acid, 2-napthylacetic acid, and 1-pyreneacetic acid) to the CH4 hydrate surface in both liquid hydrocarbon and aqueous phases has been investigated using molecular dynamics simulations, aiming to provide implications for hydrate antiagglomeration. Simulation results indicate that the liquid-phase environment, that is, the liquid hydrocarbon phase or aqueous phase, especially its hydrophilic/hydrophobic property, could profoundly affect the interfacial structures of CH4 hydrate and the adsorption behavior of aromatic carboxylic acids. In the hydrophobic hydrocarbon phase, with many CH4 molecules dissolved, more interfacial hydrate structures decompose and form a thin quasiliquid water film on the hydrate surface; aromatic carboxylic acids act as surfactants, that is, strongly adsorb to the hydrate/hydrocarbon interface and significantly lower the interfacial tension. Moreover, they adsorb to the interfacial water film on the hydrate surface with their carboxylic groups, which may destabilize the capillary liquid bridges formed among hydrate particles and then prevent hydrate coalescence. By contrast, fewer interfacial hydrate structures decompose in the aqueous phase, as CH4 molecules rarely dissolve in water but stay at the hydrate/water interface and stabilize the hydrate solid; only a few aromatic carboxylic acids adsorb to the hydrate/water interface by inserting their aromatic rings into the semicages on the hydrate surface, which may kinetically disturb the hydrate growth. Such adsorption is not very strong and mainly depends on the size matching between aromatic rings and semicages. Consequently, many more aromatic carboxylic acid molecules strongly adsorb to the hydrate surface in the hydrocarbon phase than in the aqueous phase, which can explain why antiagglomerants generally show a higher performance in the hydrocarbon phase and easily lose efficacy at high watercuts. Additionally, the molecular structures could also affect the adsorption behavior of aromatic carboxylic acids: with more aromatic rings, acid molecules can form stable aggregates via the pi-pi stacking interactions of the aromatic rings, adversely affecting the adsorption in the aqueous phase

Comparative analysis of series fault arc detection methods

For uncertainty of line fault location, current series fault arc detection methods are mainly based on current signal analysis. By comparing current waveforms before and after series arc fault under different loads, characteristics and regularities of series fault arc current were obtained. Taking current signal of series fault arc as research object, three kinds of series fault arc detection methods were introduced which use Hilbert-Huang transform, information entropy and short-time Fourier transform and wavelet approximate entropy and support vector machine respectively. Extraction processes of fault arc feature with different detection methods were summarized, and advantages and disadvantages of the three methods were compared. A view was pointed out that the detection method based on Hilbert-Huang transform and the one based on information entropy and short-time Fourier transform can effectively extract time-frequency characteristics of fault arc, and series fault arc can be identified according to proper threshold of time-frequency spectrum amplitude with low accuracy and real-time performance. The detection method based on wavelet approximate entropy and support vector machine can directly extract approximate entropy as input of support vector machine to detect series fault arc with higher accuracy and real-time performance, which is more suitable for coal mine

Photoluminescence of ZnO thin films grown on GaN templates by atmospheric pressure MOCVD

In this paper, we report the photoluminescence properties of ZnO thin films on (0 0 0 1) sapphire and GaN/c-Al2O3 template grown by atmospheric pressure metal-organic chemical vapor deposition (AP-MOCVD) using deionized water and diethylZinc as the O and Zn precursors, respectively. The two kinds of samples have very sharp band-edge PL emission at room temperature. The A and B exitons were clearly observed at 10 K in both samples, and the four phonon replicas and the C exciton or the first excited state of A exciton could be clearly observed in ZnO/GaN/Al2O3 film. The Huang-Rhys factor S of the ZnO/Al2O3 sample is two times larger than that of the ZnO/GaN/Al2O3 sample, which shows that the stronger exciton phonon interaction in the ZnO/Al2O3 sample is stronger. The PL performance strongly suggests that high-quality ZnO films can be grown on the template of GaN/Al2O3 by AP-MOCVD. (c) 2006 Elsevier B.V. All rights reserved