680 research outputs found
Characteristics of the Jinwuwei and Its Relationship to the Xingjun System
No full textThis article analyzes the relationship between the Jinwuwei 金吾衛, which was one of the twelve central guards (Shierwei 十二衛), and the system of the army in the field (Xingjun 行軍), through an examination of Tang period tactical manuals, like Taibaiyin-jing 太白陰経, and the statutes concerning the duties of Jinwuwei contained in Tongdian (通典).The research to date argues that since the main duty of the Jinwuwei was to patrol the capital palace, it was more a security police force than an army regiment. This notion is based on Tangliudian 唐六典, by and large an explanation of various Tang institutions. However, according to Tongdian, the majority of the statutes concerning the duties of Jinwuwei was derived from the Xingjun system as described in the Tang tactical manuals.During the Beizhao 北朝 and Sui-Tang periods, whenever an army in the field was organized, a unit called yuhoujun 虞候軍 was usually formed within it to take charge of reconnaissance and sentry duties during military operations, the same duties entrusted to the Jinwuwei. In other words, the main purpose of the Jinwuwei was to guard the Emperor like a yuhoujun unit, whenever he journeyed away from the capital.The author concludes that the Jinwuwei should be considered essentially a yuhoujun unit within the Shierwei, the army in the field (Xingjun) under the direct command of the Emperor.journal articl
Photonic Integration Circuits in China
No full textPhotonic integrated circuits (PICs) technologies in China have made rapid progress in the past decade. In this paper, recent advances and future prospective of PICs in China are introduced and discussed, respectively. More than nine major projects in the field of PICs have been issued. Various material platforms and technologies have been developed to realize photonic integrated devices for many applications focusing on broadband communication, such as optical and wireless network, optical interconnects, and optical coherent communication. Many research achievements and breakthrough have been made under the support of these projects, such as silicon photonics transceiver, InP- based transceiver, and optical and microwave signal processing chips. It can be expected that the PICs technology will be continuously supported in the next five years, since it has been considered as one of the key enabling technologies for supporting several national major assignments and strategies, such as broadband communication, supercomputing and datacenter.National Natural Science Foundation of China [61321063, 61090390, 61522509, 61535012]; National High-Tech Research and Development Program of China [2011AA010303, 2011AA010305]; Thousand Young Talent ProgramSCI(E)[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]
Biodegradable Zn–Mn–Li alloy with a promising balance of mechanical property and corrosion resistance
No full textTo address the current issues of brittleness and lower mechanical performance for Zn alloys, the Zn–Mn–Li system that has significant potential for enhancing strength and toughness is selected for the design, fabrication, and investigation. Li and Mn are selected as alloying elements, and a series of Zn-0.4Mn-xLi alloys are prepared. A comprehensive study of as-cast alloys is conducted on the microstructure, mechanical properties, and corrosion behavior. The results reveal that the initially precipitated β-LiZn4 phase in the as-cast Zn-0.4Mn-xLi alloys gradually transforms into a β-LiZn4/Zn lamellar structure with the increase of Li content. The β-LiZn4/Zn lamellar structure significantly contributes to the strength of the alloy. The as-cast Zn-0.4Mn-0.8Li alloy exhibits optimal mechanical strength, with yield strength and ultimate tensile strength of 203.2 ± 8.9 MPa and 271.5 ± 20.0 MPa, respectively. Electrochemical and immersion experiments indicate a dense Li-rich corrosion product layer formed on the alloy surface suppresses the generation of pitting corrosion and enhances the corrosion resistance of the alloy. These results manifest that the Li content of the Zn–Mn–Li alloy has a significant influence on the performance, such as the microstructure, mechanical properties, and corrosion behavior. According to the results of mechanical properties and corrosion behavior, Zn-0.4Mn-0.8Li alloy exhibits an optimal comprehensive performance, which provides valuable insight for the development of superior Zn–Mn–Li alloys
Earthworms increase forest litter mass loss irrespective of deposited compounds – A field manipulation experiment in subtropical forests
No full textEarthworms modulate carbon and nitrogen cycling in terrestrial ecosystems, but their effect may be compromised by the deposition of pollutants from industrial emissions. However, studies investigating how deposited compounds affect the role of earthworms in carbon cycling such as litter decomposition are lacking, although the interactions of earthworms and deposited compounds are important for understanding the impact of pollutants on ecosystems and the potential of earthworms in bioremediation. We performed a 365-day in situ litterbag decomposition experiment in a deciduous (Quercus variabilis) and coniferous (Pinus massoniana) forest in southeast China. We manipulated nitrogen (N), sodium (Na), and polycyclic aromatic hydrocarbons (PAHs) as model compounds during litter decomposition with and without earthworms (Eisenia fetida). After one year, N, Na, and PAH all slowed down litter mass loss, with the effects of Na being the strongest. By contrast, E. fetida generally increased litter mass loss, and the positive effects were uniformly maintained irrespective of the type of compounds added. However, the pathways to how earthworms increased litter mass loss varied among the compounds added and the two forests studied. As indicated by structural equation modeling, earthworms mitigated the negative effects of deposited compounds by directly increasing litter mass loss and indirectly increasing soil pH and microbial biomass. Overall, the results indicate that the acceleration of litter mass loss by earthworms is little affected by deposited compounds, and that earthworms have the potential to mitigate negative impacts of pollutants on litter decomposition and ecosystem processes.Jiangsu Forestry Science and technology innovation and promotion projectKey specialized research and development breakthrough program in Henan provinceNational Natural Science Foundation of China http://dx.doi.org/10.13039/501100001809Scholarship of China Scholarship CouncilStrategic Priority Research Program of the Chinese Academy of Sciences (A)The Key Program of Scientific Research projects of Hunan Provincial Education DepartmentOpen-Access-Publikationsfonds 202
Tuning Edge States in Strained-Layer InAs/GaInSb Quantum Spin Hall Insulators
No full textWe report on a class of quantum spin Hall insulators (QSHIs) in strained-layer InAs/GaInSb quantum wells, in which the bulk gaps are enhanced up to fivefold as compared to the binary InAs/GaSb QSHI. Remarkably, with consequently increasing edge velocity, the edge conductance at zero and applied magnetic fields manifests time reversal symmetry-protected properties consistent with the Z(2) topological insulator. The InAs/GaInSb bilayers offer a much sought-after platform for future studies and applications of the QSHI.NSF [DMR-1508644]; Welch Foundation [C-1682]; National Basic Research Program of China (NBRPC) [2014CB920901]; NSFC [11434010]; NBRPC [2015CB921503]; RCQM, Rice UniversitySCI(E)ARTICLE511
High-contrast visualization of upconversion luminescence in mice using time-gating approach
No full textPublished: February 25, 2016Optical imaging through the near-infrared (NIR) window provides deep penetration of light up to several centimeters into biological tissues. Capable of emitting 800 nm luminescence under 980 nm illumination, the recently developed upconversion nanoparticles (UCNPs) suggest a promising optical contrast agent for in vivo bioimaging. However, presently they require high-power lasers to excite when applied to small animals, leading to significant scattering background that limits the detection sensitivity as well as a detrimental thermal effect. In this work, we show that the time-gating approach implementing pulsed illumination from a NIR diode laser and time-delayed imaging synchronized via an optical chopper offers detection sensitivity more than 1 order of magnitude higher than the conventional approach using optical band-pass filters (S/N, 47321/6353 vs 5339/58), when imaging UCNPs injected into Kunming mice. The pulsed laser illumination (70 μs ON in 200 μs period) also reduces the overall thermal accumulation to 35% of that under the continuous-wave mode. Technical details are given on setting up the time-gating unit comprising an optical chopper, a pinhole, and a microscopy eyepiece. Being generally compatible with any camera, this provides a convenient and low cost solution to NIR animal imaging using UCNPs as well as other luminescent probes.Xianlin Zheng, Xingjun Zhu, Yiqing Lu, Jiangbo Zhao, Wei Feng, Guohua Jia, Fan Wang, Fuyou Li, and Dayong Ji
CMOS-compatible and fabrication-tolerant MMI-based polarization beam splitter
No full textA compact multimode interference (MMI) coupler based polarization beam splitter (PBS) is proposed and realized, which is fabrication-tolerant and fully compatible with standard silicon photonic foundry processes. The PBS On the 220 nm silicon strip waveguide is as small as 4.2 mu m x 132.64 mu m. Besides, the simulated fabrication tolerances of the width, the length and the etching depth are more than 100 nm (80 nm), 5 mu m (5.65 mu m) and 60 nm (120 nm) for TE (TM) mode, respectively. In addition, the experimental results demonstrate that the bandwidth is about 26 nm with the extinction ratio better than 15 dB. (C) 2014 Elsevier B.V. All rights reserved.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000345641500009&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701OpticsSCI(E)[email protected]; [email protected]
Direct digital control in heating, ventilating and air-conditioning in a class 100 clean room
No full textThis dissertation describes a methodology for the HVAC system and the DDC control system. Electronic analog controllers, sensors, and actuators have been successfully applied to these critical control requirements.Master of Science (Computer Control and Automation
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