Optical properties of InAs<Subscript>1−x</Subscript>N<Subscript>x</Subscript>/In<Subscript>0.53</Subscript>Ga<Subscript>0.47</Subscript>As single quantum wells grown by gas source molecular beam epitaxy

Optical properties of InAs_1−xN_x/In_0.53Ga_0.47As (hereafter, abbreviated as InAsN/InGaAs) single quantum wells (SQWs) grown on InP substrates by gas source molecular-beam epitaxy are studied using photoluminescence (PL) measurements. By comparing the low-temperature PL spectra of InAs/InGaAs and InAsN/InGaAs SQWs, InAs and InAsN phases are found to coexist in the InAsN layer. Such serious alloy inhomogeneities result in obvious exciton localization by potential irregularities. The blue shift of the PL peak after rapid thermal annealing (RTA) is found to originate mainly from As-N interdiffusion inside the well layer. According to the temperature-dependent PL results, uniformity of the InAsN layer can be effectively improved by RTA, and the exciton localization is, thus, relieved. Comparison of luminescence quenching and excitation-power-dependent PL behavior between the QWs with and without nitrogen content suggests that the quality of the QW is degraded by the introduction of nitrogen, and the degradation can only be partially recovered by post-growth RTA.     

Highly Visible Photocatalytic Activity of Fluorine and Nitrogen Co-doped Nanocrystalline Anatase Phase Titanium Oxide Converted From Ammonium Oxotrifluorotitanate

The formation of high-quality fluorine and nitrogen co-doped nanocrystalline anatase phase titanium oxide converted from ammonium oxotrifluorotitanate discoid crystal by means of thermal treatment is reported in this study. The decomposition rate of methylene blue under 450 nm light-emitting diode illumination demonstrates an excellent visible photocatalytic activity. The highest visible photocatalytic activity is obtained at the thermal treatment temperature of 600 degC. We confirm the positive roles of fluorine and nitrogen in titanium oxide in the area of visible photocatalytic activity. There is one-to-one correspondence between the life of an electron and hole pair and photocatalytic activity     

Two-Stage pyrolysis model of PVC

The pyrolysis of polyvinyl chloride (PVC) was examined with a thermal gravimetric analyzer (TGA). The experiments were carried out over the temperature range of 400-800 K at three heating rates of 1, 2, and 5.5 K/min and in a nitrogen atmosphere. The results indicate that the entire process of PVC pyrolysis under the experimental conditions of this investigation consists of two distinct pyrolysis stages, namely, the thermal dehydrochlorination and the breakdown of the intermediate products produced after the dehydrochlorination stage. The corresponding activation energy, pre-exponential factor, and reaction order were determined. A two-stage pyrolysis model, which is composed of four reactions including a number of independent, consecutive and competitive reactions with volatiles and solid products, was developed. This kinetic model gives good agreement with the experimental results.     

Strategy for the expansion of an existing steam rankine cycle to A combined cycle

A systematic procedure for designing an expansion of the steam Rankine cycle to a combined cycle is proposed. This paper discusses the approach from the point of view of overall thermodynamic efficiency. Practical limitations in design considerations are also addressed. The application of this approach is illustrated with a typical utility system design.     

Short-channel MOSFETs with oxynitride gate dielectrics fabricated using multiple rapid thermal processing

Short-channel MOSFETs with superior thin gate dielectrics have been successfully fabricated using multiple reactive rapid thermal processing of thermal oxides. The gate dielectrics are produced by rapid thermal nitridation (RTN) of thin thermal oxides in pure NH/sub 3/ ambient followed by rapid thermal reoxidation (RTO) in O/sub 2/ ambient. Devices fabricated with RTO/RTN gate dielectrics exhibit improved hot electron induced degradation compared to those fabricated with pure oxides. In addition, the subthreshold leakage current level of RTO/RTN devices is as good as for standard oxide devices.<>     

Spatial filtering of first-arriving light

The effect of combining low-pass spatial filtering with the first-arriving-light method for imaging through a scattering medium was investigated. The modification is highly effective for media having a significant specular transmission component but is essentially ineffective for media without a specular component.     

Beyond the trade-offs on Facebook: the underlying mechanisms of privacy choices

The theory of privacy calculus in terms of the trade-offs between benefits and risks is believed to explain people’s willingness to disclose private information online. However, the phenomenon of privacy paradox, referring to the preference-behavior inconsistency, misfits the risk–benefit analysis. The phenomenon of privacy paradox matters because it reflects an illusion of personal control over privacy choices. The anomaly of privacy paradox is perhaps attributed to cognitive heuristics and biases in making privacy decisions. We consider the stability-instability of privacy choices is better used to explain the underlying mechanisms of paradoxical relationship. A rebalanced trade-off, referring to the embeddedness of “bridging” and “bonding” social support in privacy calculus, is derived to develop the risk–benefit paradigms to explain the underlying mechanisms. In this study we address the underlying mechanisms of privacy choices in terms of self-disclosure and user resistance. To test the hypotheses (or mechanisms) of the research model, we developed the instrument by modifying previous scales. A general sample of 311 experienced Facebook users was collected via online questionnaire survey. From the empirical results, perceived benefits based on information support rather than emotion support can motivate self-disclosure willingness. In contrast, privacy risks rather than privacy concerns inhibit the willingness to disclose private information. The risk–benefit paradigms instead of the imbalanced trade-offs help to explain the instability of privacy choices where privacy calculus sticks with the stability view. Implications for the theory and practice of privacy choices are discussed accordingly.

     

Performance-based dynamic loop scheduling in heterogeneous computing environments

With the rapid advance of computing technologies, it becomes more and more common to construct high-performance computing environments with heterogeneous commodity computers. Previous loop scheduling schemes were not designed for this kind of environments. Therefore, better loop scheduling schemes are needed to further increase the performance of the emerging heterogeneous PC cluster environments. In this paper, we propose a new heuristic for the performance-based approach to partition loop iterations according to the performance weighting of cluster/grid nodes. In particular, a new parameter is proposed to consider HPCC benchmark results as part of performance estimation. A heterogeneous cluster and grid were built to verify the proposed approach, and three kinds of application program were implemented for execution on cluster testbed. Experimental results show that the proposed approach performs better than the previous schemes on heterogeneous computing environments.     

Billiard Combat Modeling and Simulation Based on Optimal Cue Placement Control and Strategic Planning

The selection of a best sequential shots for a given start cue position is a major challenging task in a billiard game. A new algorithm is proposed as a strategy to apply maximum tolerance angle search sequentially. The strategy considers combinations among all pockets and target object balls during both the pre and post collision shots selection processes. A simulation program is developed to test the strategy in a competition scenario by players with different proficiencies. The level of proficiency of players in the competition is controlled by a threshold value as a criterion to evaluate capability to conduct consecutive shots and when to give out right of play. The winning score of each game (win rate) is used as a performance comparison index among different gaming situations and to verify the effectiveness of the algorithm. The initial results of several simulation games using our strategy show that higher proficiency player can out beat lower proficiency player easily. This is consistent with the gaming situation in the real world, showing the consistency of our simulation program. The simulation also verifies that the play order does decide the final competition outcomes, when the players?? proficiencies are close to each other. This work is the first to investigate the effects of consecutive shots and order of play on the billiard gaming results. A low cost training system is proposed to verify the efficiency of the repositioning algorithm in real world settings. The system adapts an augmented reality technology to instruct users for reliable aiming assistance. It makes use of a vision system for cue ball, object ball locations and cue stick velocity tracking. In all, the simulation program can provide an initial proof of the effectiveness of the reposition algorithm in the competition situation. Experiments results of maximum tolerance angle all pocket search strategy using our training facility as tested by users with different skill levels all out performed the results without guidance for the set of users with the same proficiency.     

Real-Time Disk Scheduling for Multimedia Applications with Deadline-Modification-Scan Scheme

Real-timedisk scheduling (RTDS) is important for time-critical multimediaapplications. In conventional approaches of real-time disk scheduling,such as SCAN-EDF, the seek-optimizing SCAN scheme is appliedto reduce the disk service time of the real-time EDF schedule.Since only tasks with the same deadline are seek-optimized, theobtained improvement of SCAN-EDF is limited. In this paper, basedon the maximum-scannable-group (MSG) concept, a deadline-modification-scan (DMS or DM-SCAN) algorithm is proposed.Our algorithm uses MSG to automatically decide the suitable taskgroups for seek-optimizing. Based on the MSG concept, we repeatedlyapply DMS to further increase disk throughput to support moretasks. We have implemented the proposed algorithm on UnixWare2.01. The appropriate problem behaviors and parameter valuesto yield good solutions are investigated. Experiments show thatDMS is better than conventional approaches in both the obtaineddisk throughput and the supported tasks. Moreover, our proposedapproach can schedule task sets that are not schedulable by EDFand SCAN-EDF.