Confocal microscopic analysis of optical crosstalk in GaN micro-pixel light-emitting diodes

© 2015 AIP Publishing LLC. The optical crosstalk phenomenon in GaN micro-pixel light-emitting diodes (LED) has been investigated by confocal microscopy. Depth-resolved confocal emission images indicate light channeling along the GaN and sapphire layers as the source of crosstalk. Thin-film micro-pixel devices are proposed, whereby the light-trapping sapphire layers are removed by laser lift-off. Optical crosstalk is significantly reduced but not eliminated due to the remaining GaN layer. Another design involving micro-pixels which are completely isolated is further proposed; such devices exhibited low-noise and enhanced optical performances, which are important attributes for high-density micro-pixel LED applications including micro-displays and multi-channel optical communications.published_or_final_versio

Understanding the Development of Problematic Use of Massively Multiplayer Online Game

Online gaming has become one of the most popular forms of online leisure activity today. Massively multiplayer online game (MMOG), being highly persistent and immersive, is however often presented as being potentially dangerous of leading to problematic use. Despite a rising concern over this emerging societal challenge, the theoretical understanding of problematic use of MMOG is lacking in the information systems literature. Therefore, the objective of this study is to propose and empirically test a theory-guided model that explains the development of problematic use of MMOG. We built our research model on the hedonic management model of addictions, and explained the role of mood modification and deficient self-regulation in the development of problematic use of MMOG. We will validate the research model using longitudinal survey design and structural equation modeling approach. We believe that the current work presents significant implications to both research and practice

The Excessive Use of Massively Multiplayer Online Games: A Theoretical Investigation

Online gaming has become one of the most popular forms of Internet applications and online entertainments today, and has reshaped the ways people communicate and interact. Massively multiplayer online games (MMOGs), being highly challenging, interactive, immersive and persistent, are however often presented as being potentially dangerous of leading gamers to play excessively. Despite a rising concern over this emerging global issue, the theoretical understanding of the excessive use of MMOGs is lacking in the IS literature. Therefore, the main objective of this study is to propose a research model to theoretically explain the development of excessive use of MMOGs. We tested our research model in longitudinal design using an online survey with 602 active MMOGs users. Our results suggested that mood regulation derived from using MMOGs predicts the excessive use. Motivations for playing MMOGs, achievement and immersion, are found important in determining mood regulation. This study provides a theoretical explanation of excessive use of MMOGs, and the results help researchers and practitioners understand the main drivers and mechanisms of the development of excessive use of MMOGs

Technology-Mediated Self-Regulation: An Implication for Preventing Online Gaming Addiction

Self-regulation has assumed an important role in online gaming addiction. Although the role of self-regulation has received increasing scholarly attention in the past decade, research on self-regulation remains new in the information systems literature. There is also a lack of understanding of how technological design features can enhance one’s self-regulation and thus prevent online gaming addiction. Therefore, we attempt to bridge these research gaps by identifying technological design features that can enhance one’s self-regulation in online gaming, as well as by developing a research model to explain how technological design features influence one’s online gaming addiction through the self-regulatory mechanisms. In this research-in-progress paper, we present our research model and hypotheses and describe our research design. We expect that this study contributes to our understanding of the intervention and prevention in the domain of technology addiction

Hadronic Production of S-wave and P-wave Charmed Beauty Mesons via Heavy Quark Fragmentation

At hadron colliders the dominant production mechanism of $(\bar bc)$ mesons with large transverse momentum is due to parton fragmentation. We compute the rates and transverse momentum spectra for production of S-wave and P-wave $(\bar b c)$ mesons at the Tevatron via the direct fragmentation of the bottom antiquark as well as the Altarelli-Parisi induced gluon fragmentation. Since all the radially and orbitally excited $(\bar b c)$ mesons below the $BD$ flavor threshold will cascade into the pseudoscalar ground state $B_c$ through electromagnetic and/or hadronic transitions, they all contribute to the inclusive production of $B_c$. The contributions of the excited S-wave and P-wave states to the inclusive production of $B_c$ are 58 and 23\%, respectively, and hence significant.Comment: Changes are made in the Discussio

Combustion of LOX with H2(sub g) under subcritical, critical, and supercritical conditions (Task 1) and experimental observation of dense spray and mixing of impinging jets (Task 2)

The objective was to achieve a better understanding of the combustion processes of liquid oxygen and gaseous hydrogen under broad range of pressure covering subcritical, critical, and supercritical conditions. The scope of the experimental work falls into the following areas: (1) design of the overall experimental setup; (2) modification of an existing windowed high pressure chamber; (3) design of the LOX feeding system; (4) provision of the safety features in the test rig design; (5) LOX cleanliness requirements; (6) cold shock testing; (7) implementation of data acquisition systems; (8) preliminary tests for system checkout; (9) modification of LOX feeding system; and (10) evaporation tests. Progress in each area is discussed

Dynamic Candidate Keypad for Stroke-based Chinese Input Method on Touchscreen Devices

Abstract -With the popularity of touchscreen devices, physical button-based keyboards are being replaced by finger-operated virtual keyboards. Entering text on these touchscreen devices is no longer limited by finger tapping activities on the keys. Text input can be performed by finger sliding over the virtual keyboard, which is well realized by the Swype technology on a typical QWERTY keyboard. Such shorthand gesturing for text input, however, may be inefficient when directly applied to Chinese input, especially in Chinese stroke-based input method. In this paper, a novel dynamic candidate keypad with use of unidirectional finger gesture on the stroke key for character selection is proposed for enhancing stroke-based Chinese input method. The new design can enhance frequently used Chinese characters searching and input using stroke-based input. The new method is implemented on the Android 2.2 platform for performance evaluation using Traditional Chinese characters set. Experimental results show that the proposed method enables users to input popular Chinese characters easier than conventional stroke-based input methods

Chaotic to ordered state transition of cathode-sheath instabilities in DC glow discharge plasmas

Transition from chaotic to ordered state has been observed during the initial stage of a discharge in a cylindrical dc glow discharge plasma. Initially it shows a chaotic behavior but increasing the discharge voltage changes the characteristics of the discharge glow and shows a period substraction of order 7 period $\to$ 5 period $\to$3 period $\to$1 period i.e. the system goes to single mode through odd cycle subtraction. On further increasing the discharge voltage, the system goes through period doubling, like 1 period $\to$ 2 period $\to$ 4 period. On further increasing the voltage, the system goes to stable state without having any oscillations.Comment: chathode-sheath, instabilities, chaos, period-subtraction, bifurcation, dc-discharg