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In our previous work, the limitation of standard type I and II power saving in IEEE 802.16e was discussed, and the idea of load-based power saving (LBPS) was proposed for better power-saving efficiency. LBPS measures traffic load and adaptively generates proper sleep schedule for the current load. Three LBPS schemes have been proposed for mobile subscriber station (MSS) power saving. In this paper, base station (BS) power saving is taken into consideration, and our previously proposed LBPS schemes, are extended and revised to integrate both BS and MSS in sleep scheduling. Two strategies of integrated power saving, MSS first and BS first, each with associated LBPS schemes are proposed in the paper. A three-staged concept combining the proposed strategies is also presented to make the best of integrated power saving. A simulation study shows that the proposed schemes can effectively achieve high power-saving efficiency for both BS and MSS. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Transition metal dichalcogenides (TMDCs) have recently attracted a tremendous amount of attention owing to their superior optical and electrical properties as well as the interesting and various nanostructures that are created by different synthesis processes. However, the atomic thickness of TMDCs limits the light absorption and results in the weak performance of optoelectronic devices, such as photodetectors. Here, we demonstrate the approach to increase the surface area of TMDCs by a one-step synthesis process of TMDC nanowalls from WO x into three-dimensional (3D) WS 2 nanowalls. By utilizing a rapid heating and rapid cooling process, the formation of 3D nanowalls with a height of approximately 150 nm standing perpendicularly on top of the substrate can be achieved. The combination of core-shell colloidal quantum dots (QDs) with three different emission wavelengths and 3D WS 2 nanowalls further improves the performance of WS 2 -based photodetector devices, including a photocurrent enhancement of 320-470% and shorter response time. The significant results of the core-shell QD-WS 2 hybrid devices can be contributed by the high nonradiative energy transfer efficiency between core-shell QDs and the nanostructured material, which is caused by the spectral overlap between the emission of core-shell QDs and the absorption of WS 2 . Besides, outstanding NO 2 gas-sensing performance of core-shell QDs/WS 2 devices can be achieved with an extremely low detection limit of 50 ppb and a fast response time of 26.8 s because of local p - n junctions generated by p - type 3D WS 2 nanowalls and n - type core-shell CdSe-ZnS QDs. Our work successfully reveals the energy transfer phenomenon in core-shell QD-WS 2 hybrid devices and shows great potential in commercial multifunctional sensing applications.

Utilization of light to boost the performance of gas sensors allows us to operate sensor devices at room temperature. Here, we, for the first time, demonstrated an indoor light-activated 3D cone-shaped MoS2 bilayer-based NO gas sensor with ppb-level detection operated at room-temperature. Large-area cone-shaped (CS)-MoS2 bilayers were grown by depositing 2 nm-thick MoO3 layers on a 2'' three-dimensional (3D) cone-patterned sapphire substrate (CPSS) followed by a sulfurization process via chemical vapor deposition. Because the exposed area of MoS2 bilayers is increased by 30%, the CS-MoS2 gas sensor (GS) demonstrated excellent performance with a response of ∼470% and a fast response time of ∼25 s after exposure to 1 ppm of NO gas illuminated by ultraviolet (UV) light with a wavelength of 365 nm. Such extraordinary performance at room temperature is attributed to the enhanced light absorption because of the light scattering effect caused by the 3D configuration and photo-desorption induced by UV illumination. For NO concentrations ranging from 2 ppm down to 0.06 ppm, the CS-MoS2 GS demonstrated a stable sensing behavior with a high response and fast response time (470% and 25 s at 2 ppm NO) because of the light absorption enhanced by the 3D structure and photo-desorption under constant UV illumination. The CS-MoS2 GS exhibits a high sensitivity (∼189.2 R% ppm-1), allowing the detection of NO gas at 0.06 ppm in 130 s. In addition, the 3D cone-shaped structure prolonged the presence of sulfur vapor around MoO3, allowing MoO3 to react with sulfur completely. Furthermore, the CS-MoS2 GS using an indoor lighting to detect NO gas at room temperature was demonstrated for the first time where the CS-MoS2 GS exhibits a stable cycling behavior with a high response (165% at 1 ppm NO) in 50 s; for concentration as low as ∼0.06 ppm, the response of ∼75% in 150 s can be achieved.

Objective: Commercial quick-heating phosphate-bonded investments are frequently used to reduce the operating time during the dental casting process. The aim of this study was to evaluate the characteristics of commercial quick-heating phosphate-bonded investments., Method and Materials: Characterization of the 2 investments (Maruvest-Speed [Megadental] and Z4 C&B [Neirynck and Vogt]) focused on the setting expansion, compressive strength, thermal expansion, and surface roughness. Two different heating methods-the quick-heating method (QHM) and conventional heating method (CHM)-were used with the investments. The dimensional accuracy and surface roughness of the nickel-chromium alloy castings obtained from the investments were also examined., Results: The Maruvest-Speed investment had a significantly greater setting expansion (2.2%) than the Z4 investment (1.1%) after a 30-minute setting time. The fired strength of both investments was greater with QHM (21.2 to 27.7 MPa) than with CHM (13.8 to 17.9 MPa). The thermal expansion of the Maruvest-Speed investment and Z4 with QHM was 1.7% and 1.4%, respectively. There was no significant difference in surface roughness of the castings between samples treated with QHM and CHM. The dimensional accuracy of the castings was larger in length and slightly deformed in bend., Conclusion: The characteristics of the 2 commercial quick-heating phosphate-bonded investments for the accelerated casting technique may be acceptable.