As deep-red semiconductor lasers are still in development, high-power deep-red lasers have traditionally relied on excimer or dye lasers, or nonlinear frequency conversion of near-infrared lasers, ...precluding efficient, compact, and affordable laser systems. Herein, the first compact watt-level all-fiber CW Pr<inline-formula><tex-math notation="LaTeX">^{3+}</tex-math></inline-formula>-doped laser operating in the deep-red waveband was developed to navigate the challenge. The all-fiber laser consists of a double-clad Pr<inline-formula><tex-math notation="LaTeX">^{3+}</tex-math></inline-formula>-doped fluoride fiber, two homemade visible fiber dichroic mirrors with a damaged intensity of <inline-formula><tex-math notation="LaTeX">\gt </tex-math></inline-formula>15 MW/cm<inline-formula><tex-math notation="LaTeX">^{2}</tex-math></inline-formula>, and a 443-nm high-power pump source with a multimode fiber-pigtail output. We exhaustively investigated the influences of the gain fiber length and the reflectivity of output mirrors on the deep-red laser performance by experiments and simulations. A maximum average power of 4.1 W at 717 nm was directly obtained under a pump power of 20.2 W, which is more than five times higher than previously reported. The laser slope efficiency is as high as 22.2%, and its power fluctuation is less than 0.93%. Such a compact high-power all-fiber deep-red laser holds promise for applications in biophotonics, biomedicine, and UV laser generation.
This article is dedicated to the memory of the late Professor Tien Lan, widely recognized as one of the key founders and pioneers of modern spatial structures in China. In addition to his significant ...contributions in research and design, this paper explores Professor Lan’s social initiatives and accomplishments, such as founding committees and associations related to spatial structures, organizing conferences, and contributing to the development of specifications for design and construction. Professor Lan’s contributions have been recognized by several prestigious awards and honors received.
This communication presents a small, low-profile planar triple-band microstrip antenna for WLAN/WiMAX applications. The goal of this communication is to combine WLAN and WiMAX communication standards ...simultaneously into a single device by designing a single antenna that can excite triple-band operation. The designed antenna has a compact size of 19 \times 25\;\text{mm}^{2} (0.152 \lambda_{0}\;\times 0.2 \lambda_{0}). The proposed antenna consists of F-shaped slot radiators and a defected ground plane. Since only two F-shaped slots are etched on either sides of the radiator for triple-band operation, the radiator is very compact in size and simple in structure. The antenna shows three distinct bands I from 2.0 to 2.76, II from 3.04 to 4.0, and III from 5.2 to 6.0 GHz, which covers entire WLAN (2.4/5.2/5.8 GHz) and WiMAX (2.5/3.5/5.5) bands. To validate the proposed design, an experimental prototype has been fabricated and tested. Thus, the simulation results along with the measurements show that the antenna can simultaneously operate over WLAN (2.4/5.2/5.8 GHz) and WiMAX (2.5/3.5/5.5 GHz) frequency bands.
The New Year festival, or Songkran, is considered the most prominent festival in Chiang Mai, the former capital of the kingdom of Lan Na in Thailand’s Upper North. The festival, held over three days ...in mid-April, marks the earth’s entry into a new solar year. The authors seek to reconstruct the origins of the Songkran festival in Chiang Mai and its historical evolution by analyzing a variety of Northern Thai sources as well as missionary reports from the nineteenth and early twentieth centuries. Special attention is given to the transformation of the state-sponsored dam hua ritual of the Lan Na kings into a ceremony under the auspices of the Thai state.
A new type of wearable button antenna for wireless local area network (WLAN) applications is proposed. The antenna is composed of a button with a diameter of circa 16 mm incorporating a patch on top ...of a dielectric disc. The button is located on top of a textile substrate and a conductive textile ground that are to be incorporated in clothing. The main characteristic feature of this antenna is that it shows two different types of radiation patterns, a monopole type pattern in the 2.4 GHz band for on-body communications and a broadside type pattern in the 5 GHz band for off-body communications. A very high efficiency of about 90% is obtained, which is much higher than similar full textile solutions in the literature. A prototype has been fabricated and measured. The effect of several real-life situations such as a tilted button and bending of the textile ground have been studied. Measurements agree very well with simulations.
A fully integrated 4 <inline-formula> <tex-math notation="LaTeX">\times </tex-math></inline-formula> 4 802.11abgn/ac/ax transceiver system-on-chip (SoC) with integrated interference analyzer and ...frequency-dependent in-phase and quadrature (IQ) (FD-IQ) calibration is presented. The FD-IQ technique helps meeting the extremely strict IQ imbalance requirement for 1-K quadratic-amplitude modulation (QAM). The pure current-mode TX baseband (BB) improves SNR to better than 50 dB, and a multi-mode local oscillator (LO) distribution circuit provides non-contiguous operation with the error vector magnitude (EVM) of less than −37 dB. The integrated interference analyzer achieves the highly reliable connection in the presence of the undesired signal and hence improves the frequency usage efficiency by identifying the wireless LAN (WLAN) and other signals in the 2G/5G band.
A low-profile horizontally polarized (HP) omnidirectional metasurface-inspired antenna is presented. To realize HP omnidirectional radiation pattern, the theory of characteristic mode is utilized to ...facilitate the analysis of three antenna structures. Then, by properly exciting the desired characteristic mode, the antenna with a wide bandwidth and good omnidirectionality, which is based on the modification of the standard patch antenna, is obtained. The simulated results show that the proposed antenna not only can obtain a low profile of 0.06λ0 (where λ0 is the free-space wavelength at 5.2 GHz), but also has a wide operating bandwidth of 16.6%. Finally, the metasurface-inspired antenna is manufactured and the error analysis between the simulated and measured results is also provided. The antenna can be applied to 5G wireless local area network systems.
The popularity of IEEE 802.11 based wireless local area networks (WLANs) has increased significantly in recent years because of their ability to provide increased mobility, flexibility, and ease of ...use, with reduced cost of installation and maintenance. This has resulted in massive WLAN deployment in geographically limited environments that encompass multiple overlapping basic service sets (OBSSs). In this article, we introduce IEEE 802.11ax, a new standard being developed by the IEEE 802.11 Working Group, which will enable efficient usage of spectrum along with an enhanced user experience. We expose advanced technological enhancements proposed to improve the efficiency within high density WLAN networks and explore the key challenges to the upcoming amendment.
This is the first meta-analysis of the pooled prevalence of insomnia in the general population of China. A systematic literature search was conducted via the following databases: PubMed, PsycINFO, ...EMBASE and Chinese databases (China National Knowledge Interne (CNKI), WanFang Data and SinoMed). Statistical analyses were performed using the Comprehensive Meta-Analysis program. A total of 17 studies with 115,988 participants met the inclusion criteria for the analysis. The pooled prevalence of insomnia in China was 15.0% (95% Confidence interval CI: 12.1%-18.5%). No significant difference was found in the prevalence between genders or across time period. The pooled prevalence of insomnia in population with a mean age of 43.7 years and older (11.6%; 95% CI: 7.5%-17.6%) was significantly lower than in those with a mean age younger than 43.7 years (20.4%; 95% CI: 14.2%-28.2%). The prevalence of insomnia was significantly affected by the type of assessment tools (Q = 14.1, P = 0.001). The general population prevalence of insomnia in China is lower than those reported in Western countries but similar to those in Asian countries. Younger Chinese adults appear to suffer from more insomnia than older adults.
CRD 42016043620.
Wireless networks are poised to enable a variety of existing and emerging multimedia streaming applications. As the use of wireless local area networks spreads beyond simple data transfer to ...bandwidth-intense, delay-sensitive, and loss-tolerant multimedia applications, addressing quality of service issues become extremely important. Currently, a multitude of protection and adaptation strategies exists in the different layers of the open systems interconnection (OSI) stack. Hence, an in-depth understanding and comparative evaluation of these strategies are necessary to effectively assess and enable the possible trade-offs in multimedia quality, power consumption, implementation complexity, and spectrum utilization that are provided by the various OSI layers. This further opens the question of cross-layer optimization and its effectiveness in providing an improved solution with respect to the above trade-offs. In this article we formalize the cross-layer problem, discuss its challenges, and present several possible solutions. Moreover, we also discuss the impact the cross-layer optimization strategy deployed at one station has on the multimedia performance of other stations. We introduce a new fairness concept for wireless multimedia systems that employs different cross-layer strategies, and show its advantages when compared to existing resource allocation mechanisms used in wireline communications. Finally, we propose a new paradigm for wireless communications based on competition, which allows wireless stations to harvest additional resources or free up resources as well as optimally and dynamically adapt their cross-layer transmission strategies to improve multimedia quality and/or power consumption.
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