143 research outputs found
Persistence of soil microbial function at the rock-soil interface in degraded karst topsoils
No full textThis is the author accepted manuscriptsExtensive and progressive rock emergence in karst ecosystems may cause localized variations in soil biogeochemical and microbial properties, and thus produce nutrient cycling 'hot spots' that could alter functional responses to perturbation. Here, we investigated the differences between microbial compositions and functions in topsoils at the rock-soil interface (RSI) compared with adjacent bulk soil along a gradient of increasing human perturbation in the Chinese Karst Critical Zone Observatory. Microbial abundance decreased with increasing perturbation and was higher at the RSI compared to bulk soil. Compared with the bulk soil, C-cycling and N cycling enzyme activities at the RSI were 72–427% higher, respectively, and those related to N cycling were 72–98% higher, and were greatest in primary forest and abandoned land. Mineral contents explained the large variances in enzyme activities suggesting that mineral availability modified microbial functions for nutrients acquisition in nutrient-poor karst system. The significantly larger nutrient contents of RSI soil in the primary forest suggest that weathering of the karst rocks in unperturbed environments is the primary source of nutrients, which is driven by microbial enzyme production. The enzyme activities related to C and N cycling were highest in abandoned land, which suggests a rapid switch in microbial function caused by nutrient limitation when cultivation ceased. In conclusion, soil microbial abundance and function next to karst rocks is higher than bulk soils and persists after recovery. This suggests that the potential for long-term recovery of very degraded karst landscapes is possible after abandonment because microbial functions for C and nutrient cycling persist in RSI 'hot spots'.Natural Environment Research Council (NERC
Revealing an Interconnected Interfacial Layer in Solid-State Polymer Sodium Batteries
No full textReplacing the commonly used nonaqueous liquid electrolytes in rechargeable sodium batteries with polymer solid electrolytes is expected to provide new opportunities to develop safer batteries with higher energy densities. However, this poses challenges related to the interface between the Na-metal anode and polymer electrolytes. Driven by systematically investigating the interface properties, an improved interface is established between a composite Na/C metal anode and electrolyte. The observed chemical bonding between carbon matrix of anode with solid polymer electrolyte, prevents delamination, and leads to more homogeneous plating and stripping, which reduces/suppresses dendrite formation. Full solid-state polymer Na-metal batteries, using a high mass loaded Na3V2(PO4)3 cathode, exhibit ultrahigh capacity retention of more than 92 % after 2 000 cycles and over 80 % after 5 000 cycles, as well as the outstanding rate capability.Accepted Author ManuscriptRST/Storage of Electrochemical Energ
Finite Element Simulation and Experimental Research on Uniformity Regulation of Microwave Heating of Composite Materials
No full textAs an attractive alternative to the traditional autoclave curing process, microwave curing has been widely used for manufacturing high-performance composites. However, the nonuniform temperature distribution during composite curing is the main problem faced by the microwave curing process, which limits its application in the aerospace industry. This paper studied the regulating effects of cavity structure and mechanical optimization methods on the uniformity of the microwave field by numerical analysis and finite element simulation, and an octagonal microwave heating device with multi-microwave generators, mode stirrers and mobile platform was developed independently and the experimental verification were finally carried out. The results showed that compared with the traditional heating device, the T800/602 carbon fiber reinforced composite laminates cured in the regulating device of microwave heating uniformity established in this paper had more uniform temperature field distribution, a more synchronous curing process and lower residual stresses
Research on effects of ions on the determination of suspended solid content in the oilfield injection water
No full textA Comparison of Control Variate Methods for Pricing Interest Rate Derivatives in the LIBOR Market Model
No full textAbstractThis paper studies the control variate method for pricing interest rate derivatives driven by the LIBOR market model. Several control variates are constructed based on distinctive approximations for the LIBOR market model. Numerical results show the great efficiency of our methods. The idea in this paper can also be extended to price other interest rate derivatives under the LIBOR market model, such asSwaptions, Caps, some path dependent interest rate derivatives, and so forth.</jats:p
Study of the photocatalytic degradation of toluene over CdS-TiO<sub>2</sub> nanoparticles supported on multi-walled carbon nanotubes by back propagation neural network
No full textEmpowering Data Analysis with Program Synthesis
Get PDFThesis (Ph.D.)--University of Washington, 2021Data manipulation and visualization support data scientists' efforts to explore and understand data throughout the exploratory analysis process. Nowadays, experienced data scientists can use programming languages like SQL and R to achieve efficient and flexible analysis, and inexperienced users can easily learn and use interactive tools to accomplish simple analysis tasks. However, the lack of tools in between interactive tools and programming systems leads to a programmability gap that prevents inexperienced users from conducting expressive analysis that only users with programming experience can achieve. To help end users traverse this gap, we apply program synthesis to build tools that can synthesize programs from examples. We first introduce Falx, a visualization by example tool that lets the user create expressive visualizations using demonstrations of how a few data points are mapped to the canvas. Falx's compositional algorithm design let it synthesize both data transformation and visualization programs directly from end-to-end demonstration. We next introduce Scythe, a SQL query synthesizer that lets the user author advanced SQL queries using input-output examples. Using a language of abstract queries, Scythe can prune families of infeasible queries to achieve synthesis efficiency. To let inexperienced users distinguish synthesized complex queries, we developed a symbolic engine to compute a distinguishing input that the two queries would return different outputs. Finally, we summarize our synthesizer building experience into a framework, Kopis, that illustrates how to build an efficient relational query synthesizer using {value-preserving abstractions}. Together, these three contributions demonstrate the value of using program synthesizers to empower future data science, and offer guidance on how to build such synthesis-powered tools efficiently for new domains
Flexible wavefront manipulation of surface plasmon polaritons without mechanical motion components
No full textWe propose a form of flexible wavefront manipulation of surface plasmon polaritons (SPPs) without any mechanical motion component. An incoming light pattern, the amplitude of which is modulated by a liquid crystal spatial light modulator, is used to illuminate a grating on an Au film acting as a light-SPP coupler. The SPPs launched from the grating have the same intensity distribution as the input light pattern. By changing the input image, continuously variable in-plane SPP focusing on the Au film is implemented. The experimental results agree well with numerical simulations. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3593005]Physics, AppliedSCI(E)EI4ARTICLE21null9
Plasmonic Demultiplexer and Guiding
No full textTwo dimensional plasmonic demultiplexers for surface plasmon polaritons (SPPs), Which consist of concentric grooves on a gold film, are proposed and experimentally demonstrated to realize light-SPP coupling, effective dispersion, and multiple-channel SPP guiding A resolution as high as 10 nm is obtained The leakage radiation microscopy imaging shows that the SPPs of different wavelengths are focused and routed into different SPP strip waveguides The plasmonic demultiplexer can thus serve as a wavelength division multiplexing element for an integrated plasmonic circuit and also a plasmonic spectroscopy or filterhttp://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000284438000018&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Chemistry, MultidisciplinaryChemistry, PhysicalNanoscience & NanotechnologyMaterials Science, MultidisciplinarySCI(E)EIPubMed29ARTICLE116433-6438
Influence of tower anticorrosion coating as contaminant on operation characteristics of composite insulator
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