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Sol-gel derived nanocrystalline and mesoporous barium strontium titanate prepared at room temperature

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Particuology 2011年第3期9卷 235-242页

作者： Mohammad Reza Mohammadi derek J.Fray Department of Materials Science & Engineering Sharif University of Technology Department of Materials Science & Metallurgy University of Cambridge

Perovskite-type barium strontium titanate （bST） thin films and powders with nanocrystalline and mesoporous structure were prepared by a straightforward particulate sol-gel route at room temperature. The prepared sol had a narrow particle size distribution of about 20 nm. X-ray diffraction （XRD） revealed that phase composition and preferable orientation growth of bST depended upon the annealing temperature. Transmission electron microscope （TEM） images showed that the crystallite size of the powders decreased with increasing annealing temperature from 8 nm at 25 ℃ down to 5 nm at 800 ℃. Field emission scanning electron microscope （FE-SEM） analysis and atomic force microscope （AFM） images revealed that bST thin films had mesoporous and nanocrystafiine structure with average grain size of 3Onm at 600 ℃. based on brunauer-Emmett-Teller （bET） analysis, the synthesized bST showed mesoporous structure containing nnres with needle, and nlate shanes and bET surface area in the range of 49-32 m^2/g at 500-800℃

关键词： barium strontium titanate Room temperature Sol-gel chemistry Nanostructure

Visualization of real-time displacement time history superimposed with dynamic experiments using wireless smart sensors and augmented reality

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Earthquake Engineering and Engineering Vibration 2023年第3期22卷 573-588页

作者： Marlon Aguero derek Doyle David Mascarenas Fernando Moreu Department of Civil Construction and Environmental EngineeringUniversity of New MexicoCentennial Engineering Center 3056MSC011070210 University Blvd NEAlbuquerqueNM 87131USA Air Force Research Laboratory Space Vehicles DirectorateKirtland Air Force BaseAlbuquerqueNM 87117USA Engineering Institute Los Alamos National LaboratoryLos AlamosNM 8754USA

Wireless smart sensors(WSS)process field data and inform inspectors about the infrastructure health and *** bridge engineering,inspectors need reliable data about changes in displacements under loads to make correct decisions about repairs and *** to displacement information in the field and in real-time remains a challenge as inspectors do not see the data in real *** data from WSS in the field undergoes additional processing and is seen at a different *** inspectors were able to see structural displacements in real-time at the locations of interest,they could conduct additional observations,creating a new,information-based,decision-making reality in the *** paper develops a new,human-centered interface that provides inspectors with real-time access to actionable structural data during inspection and monitoring enhanced by augmented reality(AR).It summarizes and evaluates the development and validation of the new human-infrastructure interface in laboratory *** experiments demonstrate that the interface that processes all calculations in the AR device accurately estimates dynamic displacements in comparison with the *** this new AR interface tool,inspectors can observe and compare displacement data,share it across space and time,visualize displacements in time history,and understand structural deflection more accurately through a displacement time history visualization.

关键词： wireless smart sensor monitoring augmented reality displacement acceleration human-infrastructure interface

Estimating the size and travel distance of Klapperhorn Mountain debris flows for risk analysis along railway, Canada

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International Journal of Sediment Research 2008年第3期23卷 275-282页

作者： C. derek MARTIN Dept. Civil and Environmental Engineering University of Alberta Edmonton Alberta Canada T6G 2W2Drs.

Debris flows occurring on Klapperhorn Mountain in the Yellowhead Pass in the Canadian Rocky Mountains pose a significant hazard to railway operations at the base of the mountain. The size (volume) and travel distance of these debris flows play an important role in assessing the risk to the railway. GIS analysis, airphoto interpretation together with field work were undertaken on two debris flows located at track mileage 54.0 and 54.3. Characteristics of these two debris flow events were analyzed, including debris flow path morphology and event behavior. Their sizes and travel distances were estimated using an empirical-statistical model (UbCDFLOW) under different initiation conditions. Their potential impact on the railway bridge was evaluated using a bridge blockage ratio.

关键词： Debris flow Size Travel distance Railway

Nanoscale electropolishing of high-purity nickel with an ionic liquid

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International Journal of Minerals,Metallurgy and Materials 2019年第5期26卷 649-656页

作者： Jon derek Loftis Tarek M.Abdel-Fattah Applied Research Center at Thomas Jefferson National Accelerator Facility and Department of Molecular biology and Chemistry at Christopher Newport University Department of Physical Sciences Virginia Institute of Marine Science College of William and Mary Faculty of Sciences Alexandria University

High purity(>99.9% composition) nickel metal specimens were used in electropolishing treatments with an acid-free ionic liquid electrolyte prepared from quaternary ammonium salts as a green polishing solution. Voltammetry and chronoamperometry tests were conducted to determine the optimum conditions for electrochemical polishing. Atomic force microscopy(AFM) revealed nanoscale effectiveness of each polishing treatment. Atomic force microscopy provided an overall observation of the material interface between the treated and unpolished regions. Surface morphology comparisons summarized electrochemical polishing efficiency by providing root-mean-square roughness averages before and after electrochemical polishing to reveal a mirror finish six times smoother than the same nickel metal surface prior to electropolishing. This transition manifested in a marked change in root-mean-squared roughness from 112.58 nm to 18.64 nm and producing a smooth mirror finish. Finally, the mechanism of the ionic liquid during electropolishing revealed decomposition of choline in the form of a transient choline radical by acceptance of an electron from the nickel-working electrode to decompose to trimethylamine and ethanol.

关键词： electrochemical polishing ionic liquid Ni 2EG:1Vb4

Factor of safety of strain-softening slopes

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第3期12卷 473-483页

作者： Hossein Rafiei Renani C.derek Martin Klohn Crippen berger Ltd. VancouverCanada Department of Civil and Environmental Engineering University of AlbertaEdmontonCanada

Stability analysis of strain-softening slopes is carried out using the shear strength reduction method and Mohr-Coulomb model with degrading cohesion and friction *** e ffect of strain-softening behavior on the slope factor of safety is investigated by performing a series of analyses for various slope geometries and strength *** charts and equations are developed to estimate the factor of safety of strain-softe ning slopes from the results of traditional stability analysis based on perfectly-plastic *** example applications including an open pit mine in weak rock and clay shale slope with daylighting bedding planes are *** results of limit equilibrium analysis and shear strength reduction method with perfectly-plastic models were in close *** perfectly-plastic models with peak strength properties led to overly optimistic results while adopting residual strength properties gave excessively conservative *** shear strength reduction method with a strain-softening model gave realistic factors of safety while accounting for the process of strength degradation.

关键词： Slope stability analysis Factor of safety ratio Shear strength reduction Perfectly-plastic behavior Open pit slope Clay shale slope

An imbalance between innate and adaptive immune cells at the maternal-fetal interface occurs prior to endotoxin-induced preterm birth

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Cellular & Molecular Immunology 2016年第4期13卷 462-473页

作者： Marcia Arenas-Hernandez Roberto Romero derek St Louis Sonia S Hassan Emily b Kaye Nardhy Gomez-Lopez Department of Obstetrics & Gynecology Wayne State University School of Medicine Detroit Michigan USA perinatology Research branch Program for Perinatal Research and Obstetrics Division of Intramural Research Eunice Kennedy ShriverNational Institute of Child l~ealth and Human DevelopmentNIC.HD/NIHDHHS Bethesda Maryland and Detroit Michigan USA Departme.nt of Obstetrics and Gynecology University of M chigan Ann ArborMichigan USA Department of Epidemiology and biostatistics Michigan State University East Lansing Michigan USA Department of Molecular Obstetrics and Genetics Wayne State University Detroit Michigan USA Department of ImmunoLogy & MicrobioLogy Wayne State University School of Medicine Detroit Michigan USA

Preterm birth （PTb） is the leading cause of neonatal morbidity and mortality worldwide. A transition from an anti-inflammatory state to a pro-inflammatory state in the mother and at the maternal-fetal interface has been implicated in the pathophysiology of microbial-induced preterm labor. However, it is unclear which immune cells mediate this transition. We hypothesized that an imbalance between innate and adaptive immune cells at the maternal-fetal interface will occur prior to microbial-induced preterm labor. Using an established murine model of endotoxin-induced PTb, our results demonstrate that prior to delivery there is a reduction of CD4 ＋ regulatory T cells （Tregs） in the uterine tissues. This reduction is neither linked to a diminished number of Tregs in the spleen, nor to an impaired production of ILIO, CCL17, or CCL22 by the uterine tissues. Endotoxin administration to pregnant mice does not alter effector CD4＋ T cells at the maternal-fetal interface. However, it causes an imbalance between Tregs （CD4＋ and CD8＋）, effector CD8＋ T cells, and Th17 cells in the spleen. In addition, endotoxin administration to pregnant mice leads to an excessive production of CCL2, CCL3, CCL17, and CCL22 by the uterine tissues as well as abundant neutrophils. This imbalance in the uterine microenvironment is accompanied by scarce APC-like cells such as macrophages and MHC II ＋ neutrophils. Collectively, these results demonstrate that endotoxin administration to pregnant mice causes an imbalance between innate and adaptive immune cells at the maternal-fetal interface.

关键词： antigen-presenting cells effector T cells inflammation labor lipopolysaccharide macrophages microbial product neutrophils pregnancy preterm labor regulatory T cells

Mantle plumes,triple junctions and transforms:A reinterpretation of Pacific Cretaceous-Tertiary LIPs and the Laramide connection

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Geoscience Frontiers 2020年第4期11卷 1133-1144页

作者： Michael Fletcher derek A.Wyman Sabin Zahirovic Earthbyte Group School of GeosciencesUniversity of SydneySydneyNew South Wales2006Australia

The Shatsky and Hess Rises,the Mid-Pacific Mountains and the Line Islands large igneous provinces(LIPs) present different challenges to conventional plume *** the genesis of these LIPs is important not only for a more complete understanding of mantle plumes and plume-generated magmatism,but also for establishing the role of subducted LIP conjugates in the evolution of the Laramide orogeny and other circum-Pacific orogenic events,which are related to the development of large porphyry *** past difficulties in developing consistent geodynamic models for these LIPs,it is useful to consider whether viable alternative geodynamic scenarios may be provided by recent concepts such as melt channel networks and channel-associated lineaments,along with the "two mode"model of melt generation,where a deeply-sourced channel network is superimposed on the plume,evolving and adapting over millions of years.A plume may also interact with transform faults in close proximity to a mid ocean ridge,with the resultant bathymetric character strongly affected by the relative age difference of lithosphere across the *** results suggest that the new two-mode melt models resolve key persistent issues associated with the Shatsky Rise and other LIPs and provide evidence for the existence of a conduit system within plumes that feed deeply-sourced material to the plume head,with flow maintained over considerable *** conduit system eventually breaks down during plume-ridge separation and may do so prior to the plume head being freed from the triple junction or spreading *** is evidence for not only plume head capture by a triple junction but also for substantial deformation of the plume stem as the distance between the stem and anchored plume head *** evidence suggests that young transforms can serve as pathways for plume material migration,at least in certain plume head-transform configurations.A fortuitous similarity between the path of the

关键词： Mantle plume Shatsky rise Hess rise Mid-pacific mountains Laramide orogeny

Ceramic water filter for point-of-use water treatment in developing countries: Principles, challenges and opportunities

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Frontiers of Environmental Science & Engineering 2020年第5期14卷 37-46页

作者： Haiyan Yang Shangping Xu derek EChitwood Yin Wang SCNU Environmental Research Institute Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety&MOE Key Laboratory of Theoretical Chemistry of EnvironmentSouth China Normal UniversityGuangzhou 510006China School of Environment South China Normal UniversityUniversity TownGuangzhou 510006China Department of Geosciences University of Wisconsin-MilwaukeeMilwaukeeWI 53211USA Department of Engineering Dordt UniversitySioux CenterIA 51250USA Department of Civil and Environmental Engineering University of Wisconsin MilwaukeeMilwaukeeWI 53211USA

Drinking water source contamination poses a great threat to human health in developing ***-of-use(POU)water treatment techniques,which improve drinking water quality at the household level,offer an affordable and convenient way to obtain safe drinking water and thus can reduce the outbreaks of waterbome *** water filters(CWFs),fabricated from locally sourced materials and manufactured by local labor,are one of the most socially acceptable POU water treatment technologies because of their effectiveness,low-cost and ease of *** review concisely summarizes the critical factors that influence the performance of CWFs,including(1)CWF manufacturing process(raw material selection,firing process,silver impregnation),and(2)source water ***,an in-depth discussion is presented with emphasis on key research efforts to address two major challenges of conventional CWFs,including(1)simultaneous increase of filter flow rate and bacterial removal efficiency,and(2)removal of various concerning pollutants,such as viruses and metal(loid)*** promote the application of CWFs,future research directions can focus on:(1)investigation of pore size distribution and pore structure to achieve higher flow rates and effective pathogen removal by elucidating pathogen transport in porous ceramic and adjusting manufacture parameters;and(2)exploration of new surface modification approaches with enhanced interaction between a variety of contaminants and ceramic surfaces.

关键词： Point-of-use water treatment Ceramic water filter bacterial removal Surface modification Water quality

Radiofrequency ablation of recurrent cholangiocarcinoma after orthotopic liver transplantation—a case report

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World Journal of Gastroenterology 2005年第4期11卷 612-613页

作者： Rakesh Rai derek Manas John Rose HPb Surgery and Liver Transplant Unit Freeman Hospital NewcastleUK Department of Interventional Radiology Freeman Hospital NewcastleUK

AIM: To report the use of radiofrequency ablation in the treatment of recurrenct cholangiocarcinoma in the transplanted ***: A lady who underwent orthotopic liver transplantation (OLT) for intrahepatic cholangiocarcinoma recurrence of tumour 13 mo after tralsplantation inspite of adjuvant chemotherapy. Her recurrent tumour was treated with radiofrequency ***: She survived for 18 mo following the recurrence of her ***: Radiofrequency ablation can be used safely in the transplanted liver to treat recurrent tumour.

关键词： Cholangiocarcinoma Orthotopic liver transplantation Radiofrequency ablation Recurrence