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2019 highlights of the structural revision of natural product via total synthesis

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Frontiers of Chemical science and Engineering 2021年第3期15卷 595-601页

作者： Zongjia Chen mark A.Rizzacasa school of Chemistry The Bio21 Molecular Science and Biotechnology InstituteThe University of MelbourneParkvilleVIC 3010Australia

For over a century,chemical synthesis has played an essential role in the structural assignment of natural *** the development of characterization instrumentation and methods[1],such as nuclear magnetic resonance(NMR),high-resolution mass spectrometry,X-ray crystallography etc.,natural product chemists view synthetic chemistry more as an assistive technology and less as a core competence.

关键词： products. NMR synthesis

Environmental noise alters gastric myoelectrical activity:Effect of age

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World Journal of Gastroenterology 2007年第3期13卷 403-407页

作者： James s Castle mark R Warner mark A Korsten Medical Program and Audiology service James J Peters VA Medical Center Bronx NY and Mount Sinai School of Medicine New York United States

AiM: To evaluate the effect of age and acoustic stress on gastric myoelectrical activity (GMA) and autonomic nervous system function. METHODs: Twenty-one male subjects (age range 22-71 years, mean 44 years) were recruited and exposed, in random order, to three auditory stimuli (Hospital noise, conversation babble and traffic noise) after a 20-min baseline. All periods lasted 20 min and were interspersed with a 10 min of recovery. GMA was obtained using a synectics Microdigitrapper. Autonomic nerve function was assessed by monitoring blood pressure and heart rate using an automatic recording device. REsULTs: Dominant power tended to decrease with increase of age (P inute (CPM) activity decreased during exposure to hospital noise (12.0%, P ic noise (13.9%, P sation babble (7.1%). The subjects in the younger group (s) showed a consistent reduction in the percentage of 3 CPM activity during hospital noise (22.9%, P ic noise (19.0%, P sation babble (15.5%). These observations were accompanied by a significant increase in bradygastria: hospital noise (P ic noise (P in contrast, the subjects over 50 years of age did not exhibit a significant decrease in 3 CPM activity. Regardless of age, noise did not alter blood pressure or heart rate. CONCLUsiON: GMA changes with age. Loud noise can alter GMA, especially in younger individuals. Our data indicate that even short-term exposure to noise may alter the contractility of the stomach.

关键词： Noise, Acoustic stress, Gastric myoelectrical activity Electrogastmgram Autonomic nervous system

Possible role of power-to-heat and power-to-gas as flexibleloads in German medium voltage networks

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Frontiers in Energy 2017年第2期11卷 135-145页

作者： mark KUPRAT Martin BENDiG Klaus PFEiFFER Forschungszentrum 3E LS EVH Siemens-Halske-Ring 13 03046Cottbus Germany

Germanys energy transition triggered a rapid and unilateral growth of renewable energy sources (REs) in the electricity sector. With increasing shares of intermittent REs, overcapacities during periods of strong wind and photovoltaic electricity generation occur. in the face of insufficient transmission capacities, due to an inhibited network extension, the electricity generation has to be curtailed. This curtailment of REs leads to economic losses and could be avoided through flexible loads. As an option to cope with those problems, the technologies of power-to-gas (PtG) and power-to-heat (PtH) are presented in this paper. First, the alkaline electrolyzer (AEL), polymer electrolyte membrane electrolyzer (PEMEL), and solid oxide electrolyzer cell (sOEC) are investigated regarding their operational parameters. second, the electric boiler, electrode heating boiler, and heat pumps are considered. Ultimately, the network-supporting abilities and the potential to provide ancillary services, such as control power, load sequence operation, cold start and part load capability, are compared among one another.

关键词： power-to-gas power-to-heat flexible loads ancillary services coherent energy systems

Reactivity of Pyrogenic Carbonaceous Matter (PCM) in mediating environmental reactions: Current knowledge and future trends

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Frontiers of Environmental science & Engineering 2020年第5期14卷 115-125页

作者： Wenqing Xu mark Lsegall Zhao Li Department of Civil and Environmental Engineering Villanova UniversityVillanovaPA 19085USA

Pyrogenic Carbonaceous Matter(PCM;e.g.,black carbon,biochar,and activated carbon)are solid residues from incomplete combustion of fussil fuel or *** are traditionally viewed as inert adsorbents for sequestering contaminants from the aqueous phase or providing surfaces for microbes to *** this account,we reviewed the recently discovered reactivity of PCM in promoting both chemical and microbial synergies that are important in pollutant transformation,biogeochemical processes of redox-active elements,and climate change mitigation with respect to the interaction between biochar and nitrous oxide(N2O).Moreover,we focused on our group's work in the PCM-enhanced abiotic transformation of nitrogenous and halogenated pollutants and conducted in-depth analysis of the reaction *** understand what properties of PCM confer its reactivity,our group pioneered the use of PCM-like polymers,namely conjugated microporous polymers(CMPs),to mimic the performance of *** approach allows for the controlled incorporation of specific surface properties(e.g.,quinones)into the polymer network during the polymer *** a result,the relationship between specific characteristics of PCM and its reactivity in facilitating the decay of a model pollutant was systematically studied in our group's *** findings summarized in this account help us to better understand an overlooked environmental process where PCM synergistically interacts with various environmental reagents such as hydrogen sulfide and ***,the knowledge gained in these studies could inform the design of a new generation of reactive carbonaceous materials with tailored properties that are highly efficient in contaminant removal.

关键词： Pyrogenic carbonaceous matter Conjugated microporous polymer Remediation Biochar Hydrolysis Pollutant degradation

Contrasting demographic trends and asymmetric migration rates in a spatially structured amphibian population

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integrative Zoology 2020年第6期15卷 482-497页

作者： Berta CAPELLÀ-MARZO Gregorio sÁNCHEZ-MONTEs iñigo MARTÍNEZ-sOLANO Department of Biodiversity and Evolutionary Biology Museo Nacional de Ciencias NaturalesCSICMadridSpain

N_(a)tural populations often persist at the landscape scale as metapopulations,with breeding units(subpopulations)experiencing temporal extinction and recolonization *** parameters to forecast population viability in these systems include the ratio of the effective number of breeders(N_(b))to the total number of adults(N_(a))and migration rates among ***,we present the results of a 10-year integrative monitoring program of a metapopulation of the iberian green frog(Pelophylax perezi)in central *** characterized population dynamics at two main breeding ponds(Gravera and Laguna)using capture-mark-recapture data to estimate N_(a)in each breeding season,and multilocus genotypes to estimate the effective population size(Ne),N_(b),individual breeding success,and migration *** ponds experienced population decline after a dry season,with Gravera subsequently recovering and Laguna suffering a bottleneck associated with genetic *** this subpopulation,average allelic richness and private alleles decreased from 2010(10.87 and 1.67,respectively)to 2018(8.0 and 0.20).The N_(b)/N_(a)ratio in Laguna in 2018 was twice as high(0.95)than in Gravera(0.41)or in pre-bottleneck Laguna(0.50),suggesting plasticity or genetic compensation through increased individual breeding *** rates were asymmetric between ponds,with a stronger contribution from Gravera to Laguna(29.9%vs.16.2%in the opposite direction)that may result in a rescue *** study emphasizes the importance of integrative demographic approaches for the monitoring of natural populations based on a better understanding of their spatio-temporal dynamics,which provides valuable information for conservation actions.

关键词： bottleneck capture-mark-recapture genetic monitoring metapopulation N_(b)/N_(a)ratio

Grain boundary effects in high-temperature liquid-metal dealloying: a multi-phase field study

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npj Computational Materials 2023年第1期9卷 1039-1049页

作者： Nathan Bieberdorf mark Asta Laurent Capolungo Department of Materials science and Engineering University of CaliforniaBerkeleyCA 94720USA Materials science and Technology Division Los Alamos National LaboratoryLos AlamosNM 87545USA

A multi-phase field model is employed to study the microstructural evolution of an alloy undergoing liquid dealloying,specifically considering the role of grain boundaries.A semi-implicit time-stepping algorithm using spectral methods is implemented,which enables simulating large 2D and 3D domains over long time scales while still maintaining a realistic interfacial *** reveal a mechanism of coupled grain–boundary migration to maintain equilibrium contact angles with the topologically complex solid–liquid interface,which locally accelerates diffusion-coupled growth of a liquid channel into the *** mechanism asymmetrically disrupts the ligament connectivity of the dealloyed structure in qualitative agreement with published experimental *** grain boundary migration-assisted corrosion channels form even for precursors with small amounts of the dissolving alloy species,below the parting *** activation of this grain boundary dealloying mechanism depends strongly on grain boundary mobility.

关键词： alloying grain alloy

soft thermal nanoimprint lithography using a nanocomposite mold

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Nano Research 2018年第5期11卷 2705-2714页

作者： Viraj Bhingardive Liran Menahem mark schvartzman Department of Materials Engineering Isle Katz Institute of Nanoscale Science and Technology Ben-Gurion University of the Negev P.O. Box 653 Beer-Sheva 8410501 Israel

soft nanoimprint lithography has been limited to ultraviolet （UV） curable resists. Here, we introduce a novel approach for soft thermal nanoimprinting. This unprecedented combination of the terms ＂soft＂ and ＂thermal＂ for nanoimprinting became possible thanks to an innovative nanocomposite mold consisting of a flexible polydimethylsiloxane （PDMs） substrate with chemically attached rigid relief features. We used soft thermal nanoimprinting to produce high-resolution nanopatterns with a sub-100 nm feature size. Furthermore, we demonstrate the applicability of our nanoimprint approach for the nanofabrication of thermally imprinted nanopattems on non-planar surfaces such as lenses. Our new nanofabrication strategy paves the way to numerous applications that require the direct fabrication of functional nanostructures on unconventional substrates.

关键词： soft lithography nanoimprint lithography polydimethylsiloxane(PDMs) non-planar substrates

Numerical modelling of high-temperature superconducting dynamos:A review

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superconductivity 2023年第1期5卷 1-16页

作者： mark D Ainslie Department of Engineering King’s College LondonStrandLondon WC2R 2LSUnited Kingdom

The high‐temperature superconducting(HTs)dynamo enables injection of large DC currents into a superconducting coil,without the need for thermally‐inefficient current *** of this important advantage,there is significant interest in using such technology to energise superconducting coils in superconducting rotating machines and NMR/MRi *** the extensive experimental work carried out over the past decade,there was–until very recently–considerable confusion and debate regarding the physical origin of the HTs dynamo’s DC output *** modelling has played a key role in elucidating the underlying physics of such devices and several different numerical models have now been developed as useful and cost‐effective tools to not only explain and further examine experimental results,but also optimise and improve dynamo *** review summarises all of the developments in this important area over recent years,including modelling the open‐circuit voltage behaviour in 2D and 3D,the definition of a new benchmark problem for the HTs modelling community,investigating key dynamo parameters,modelling dynamic coil charging behaviour and calculating losses.A view towards the future is provided,including the outstanding challenges and the developments required to address these.

关键词： HTs modelling HTs dynamo HTs flux pump High temperature superconductors Numerical simulation Finite‐element method

Extreme wave loads on submerged water intakes in shallow water

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Journal of Hydrodynamics 2015年第1期27卷 38-51页

作者： CORNETT Andrew HECiMOViCH mark NisTOR ioan Ocean Coastal and River Engineering National Research Council Department of Civil Engineering University of Ottawa

This paper provides new guidance concerning the hydrodynamic loads on submerged intake structures located in shallow water under breaking and non-breaking waves. Results from a series of experiments conducted in a large wave flume at 1 ： 15 scale to study the hydrodynamic forces exerted on a generic intake structure located on a sloping seabed in shallow water below breaking and non-breaking irregular waves are presented. Based on analysis of the experimental data, empirical relationships are developed to describe the peak loads in terms of characteristic wave parameters such as significant wave height and peak wave period. The distribution of the peak loads across different parts of the intake structure is also described. Drag and inertia force coefficients for the horizontal forcing on the intake structure and for the main structural sub-components are derived and presented. it is shown that the well-known Morison equation, with appropriate drag and inertia force coefficients, can provide reasonable estimates of the moderate horizontal loads, but the peak loads are less well predicted.

关键词： wave force water intake drag force inertia force coastal engineering