检索结果-南通市图书馆

Slice Thickness Optimization for the Focused Ion Beam-Scanning electron Microscopy 3D Tomography of Hierarchical Nanoporous Gold

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nanomanufacturing and Metrology 2022年第2期5卷 112-118页

作者： Alexander Shkurmanov Tobias Krekeler martin Ritter electron Microscopy Unit Hamburg University of Technology(TUHH)Eißendorfer Straße 4221073HamburgGermany

The combination of focused ion beam (FIB) with scanning electron microscopy (SeM), also known as FIB-SeM tomography, has become a powerful 3D imaging technique at the nanometer scale. This method uses an ion beam to mill away a thin slice of material, which is then block-face imaged using an electron beam. With consecutive slicing along the z-axis and subsequent imaging, a volume of interest can be reconstructed from the images and further analyzed. Hierarchical nanoporous gold (HNPG) exhibits unique structural properties and has a ligament size of 15–110 nm and pore size of 5–20 nm. Accurate reconstruction of its image is crucial in determining its mechanical and other properties. Slice thickness is one of the most critical and uncertain parameters in FIB-SeM tomography. For HNPG, the slice thickness should be at least half as thin as the pore size and, in our approach, should not exceed 10 nm. Variations in slice thickness are caused by various microscope and sample parameters, e.g., converged ion milling beam shape, charging effects, beam drift, or sample surface roughness. Determining and optimizing the actual slice thickness variation appear challenging. In this work, we examine the influence of ion beam scan resolution and the dwell time on the mean and standard deviation of slice thickness. After optimizing the resolution and dwell time to achieve the target slice thickness and lowest possible standard deviation, we apply these parameters to analyze an actual HNPG sample. Our approach can determine the thickness of each slice along the z-axis and estimate the deviation of the milling process along the y-axis (slow imaging axis). For this function, we create a multi-ruler structure integrated with the HNPG sample.

关键词： Focused ion beam Scanning electron microscopy Tomography Hierarchical nanoporous gold

A numerical investigation into key factors controlling hard rock excavation via electropulse stimulation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical engineering 2020年第4期12卷 793-801页

作者： Daniel Vogler Stuart DCWalsh martin OSaar Geothermal energy and Geofluids Institute of GeophysicsETH ZurichZurichSwitzerland Department of Civil engineering Monash UniversityMelbourneAustralia Department of earth and environmental Sciences University of MinnesotaMinneapolisUSA

electropulse stimulation provides an energy-efficient means of excavating hard rocks through repeated application of high voltage pulses to the rock *** such,it has the potential to confer significant advantages to mining and drilling operations for mineral and energy ***,before these benefits can be realized,a better understanding of these processes is required to improve their deployment in the *** this paper,we employ a recently developed model of the grain-scale processes involved in electropulse stimulation to examine excavation of hard rock under realistic operating *** that end,we investigate the maximum applied voltage within ranges of 120e600 kV,to observe the onset of rock *** further study the effect of grain size on rock breakage,by comparing fine(granodiorite)and coarse grained(granite)***,the pore fluid salinity is investigated,since the electric conductivity of the pore fluid is shown to be a governing factor for the electrical conductivity of the modeled *** study demonstrates that all investigated factors are crucial to the efficiency of rock fragmentation by electropulsing.

关键词： electropulse stimulation High voltage breakdown Numerical modeling Drilling Thermo-mechanics

The need for adaptable global guidance in health systems strengthening for musculoskeletal health:a qualitative study of international key informants

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Global Health Research and Policy 2021年第1期6卷 247-268页

作者： Andrew M.Briggs joanne e.Jordan Deborah Kopansky-Giles Saurab Sharma Lyn March Carmen Huckel Schneider Swatee Mishrra James J.Young Helen Slater Curtin School of Allied Health Curtin UniversityPerthAustralia HealthSense(Aust)Pty Ltd MelbourneAustralia Department of Research Canadian Memorial Chiropractic CollegeTorontoCanada Department of Family&Community Medicine University of TorontoTorontoCanada Department of Physiotherapy Kathmandu University School of Medical SciencesDhulikhelNepal Department of Rheumatology Royal North Shore HospitalSydneyAustralia Sydney Musculoskeletal Bone&Joint Health AllianceFaculty of Medicine and HealthUniversity of SydneySydneyAustralia Menzies Centre for Health Policy and economics Faculty of Medicine and HealthUniversity of SydneySydneyAustralia Center for Muscle and Joint Health Department of Sports Science and Clinical BiomechanicsUniversity of Southern DenmarkOdenseDenmark

Background:Musculoskeletal(MSK)conditions,MSK pain and MSK injury/trauma are the largest contributors to the global burden of disability,yet global guidance to arrest the rising disability burden is *** aimed to explore contemporary context,challenges and opportunities at a global level and relevant to health systems strengthening for MSK health,as identified by international key informants(KIs)to inform a global MSK health strategic ***:An in-depth qualitative study was undertaken with international KIs,purposively sampled across highincome and low and middle-income countries(LMICs).KIs identified as representatives of peak global and international organisations(clinical/professional,advocacy,national government and the World Health Organization),thought leaders,and people with lived experience in advocacy *** transcripts of individual semi-structured interviews were analysed inductively using a grounded theory *** were organised into categories describing 1)contemporary context;2)goals;3)guiding principles;4)accelerators for action;and 5)strategic priority areas(pillars),to build a data-driven logic ***,we report on categories 1–4 of the logic ***:Thirty-one KIs from 20 countries(40%LMICs)affiliated with 25 organisations *** themes described contemporary context(category 1):1)MSK health is afforded relatively lower priority status compared with other health conditions and is poorly legitimised;2)improving MSK health is more than just healthcare;3)global guidance for country-level system strengthening is needed;4)impact of COVID-19 on MSK health;5)multiple inequities associated with MSK health;and 6)complexity in health service delivery for MSK *** guiding principles(category 3)focussed on adaptability;inclusiveness through co-design;prevention and reducing disability;a lifecourse approach;and equity and value-based ***(category 2)and seven accelerators for action(category 4)were al

关键词： Global health Disability Rehabilitation Musculoskeletal Strategy Systems strengthening

Human umbilical artery smooth muscle exhibits a 2-APBsensitive capacitative contractile response evoked by vasoactive substances and expresses mRNAs for STIM, Orai and TRPC channels

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

BIOCeLL 2012年第2期36卷 73-81页

作者： ANA ROCÍO ROLDÁN PALOMO PeDRO martin ALeJANDRO ReBOLLeDO NICOLÁS eNRIQUe LUIS e.FLOReS VeRÓNICA MILeSI GINFIV–Grupo de Investigación en Fisiología Vascular Facultad de Ciencias ExactasUniversidad Nacional de La Plata.Argentina CeNeXA–Centro de endocrinología experimental y Aplicada (UNLP-CONICET La PlataCentro Colaborador OPS/OMS)Facultad de Ciencias MédicasUniversidad Nacional de La Plata.Argentina

After depletion of intracellular Ca^(2+)stores the capacitative response triggers an extracellular Ca^(2+)influx through store-operated channels(SOCs)which refills these *** objective was to explore if human umbilical artery smooth muscle presented this response and if it was involved in the mechanism of serotonin-and histamine-induced *** Ca^(2+)depletion by a Ca^(2+)-free extracellular solution followed by Ca^(2+)readdition produced a contraction in artery rings which was inhibited by the blocker of Orai and TRPC channels 2-aminoethoxydiphenyl borate(2-APB),suggesting a capacitative *** presence of 2-APB the magnitude of a second paired contraction by serotonin or histamine was significantly less than a first one,likely because 2-APB inhibited store refilling by capacitative Ca^(2+)entry.2-APB inhibition of sarcoplasmic reticulum Ca^(2+)release was excluded because this blocker did not affect serotonin force development in a Ca^(2+)-free *** PCR technique showed the presence of mRNAs for STIM proteins(1 and 2),for Orai proteins(1,2 and 3)and for TRPC channels(subtypes 1,3,4 and 6)in the smooth muscle of the human umbilical ***,this artery presents a capacitative contractile response triggered by stimulation with physiological vasoconstrictors and expresses mRNAs for proteins and channels previously identified as SOCs.

关键词： human umbilical artery capacitative response TRPC channels serotonin histamine

Convergent Data-Driven Regularizations for CT Reconstruction

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications on Applied Mathematics and Computation 2024年第2期6卷 1342-1368页

作者： Samira Kabri Alexander Auras Danilo Riccio Hartmut Bauermeister martin Benning Michael Moeller martin Burger Helmholtz Imaging Deutsches Elektronen-Synchrotron DESYNotkestr.8522607 HamburgGermany Institute for Vision and Graphics University of SiegenAdolf-Reichwein-Straße 2a57076 SiegenGermany School of Mathematical Sciences Queen Mary University of LondonMile End RoadLondon E14NSUK The Alan Turing Institute British Library96 Euston RdLondon NW12DBUK Fachbereich Mathematik Universitat HamburgBundesstrasse 5520146 HamburgGermany

The reconstruction of images from their corresponding noisy Radon transform is a typical example of an ill-posed linear inverse problem as arising in the application of computerized tomography(CT).As the(naive)solution does not depend on the measured data continuously,regularization is needed to reestablish a continuous *** this work,we investigate simple,but yet still provably convergent approaches to learning linear regularization methods from *** specifically,we analyze two approaches:one generic linear regularization that learns how to manipulate the singular values of the linear operator in an extension of our previous work,and one tailored approach in the Fourier domain that is specific to *** prove that such approaches become convergent regularization methods as well as the fact that the reconstructions they provide are typically much smoother than the training data they were trained ***,we compare the spectral as well as the Fourier-based approaches for CT-reconstruction numerically,discuss their advantages and disadvantages and investigate the effect of discretization errors at differentresolutions.

关键词： Inverse problems Regularization Computerized tomography(CT) Machine learning

Mathematical model and energy analysis of ethane dehydration in two-layer packed-bed adsorption

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2019年第6期17卷 33-40页

作者： Yadollah Tavan Seyyed Hossein Hosseini Goodarz Ahmadi martin Olazar Chemical and Petroleum engineering Department Sharif University of TechnologyAzadi Av.TehranIran Chemical engineering Department Faculty of EngineeringIlam University69315-516 IlamIran Department of Mechanical and Aeronautical engineering Clarkson UniversityPotsdamNY 13699-5725USA Department of Chemical engineering Faculty of Science and TechnologyUniversity of the Basque CountryP.O.Box 64448080 BilbaoSpain

The 3A zeolites are excellent adsorbents for industrial-scale gas dehydration because of the low energy required for regeneration and ease of operation.A computational study of the dehydration of an industrial feed stream containing ethane and water was performed using an in-house code that included an appropriate equilibrium adsorption *** validated computational model was used to examine the impact of particle size on the process dynamics and the corresponding pressure *** water concentration along the adsorption column was also *** increase the process capacity,the packed adsorption bed was divided into two distinct layers,which were operated with different particle *** length of each layer was determined by a parametric *** best breakthrough time,i.e.,107,800 s,at the allowed pressure drop was obtained when the lengths of the first and second layers were 4.5 and 1 m,*** results showed that the new two-layer adsorption bed could save around 33.8%in total energy requirement in comparison to that of a single bed.

关键词： Molecular sieve Breakthrough Adsorption ethane dehydration Mathematical model

Numerical simulation of flooding induced uplift for abandoned coal mines:simulation schemes and parameter sensitivity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Coal Science & Technology 2021年第6期8卷 1238-1249页

作者： Jian Zhao Heinz Konietzky martin Herbst Roy Morgenstern Geotechnical Institute TU Bergakademie FreibergGustav-Zeuner-Straβe 109599 FreibergGermany

Numerical simulation approaches have been widely applied to study mining induced subsidence,and they are potential methods to study the flooding induced uplift for abandoned *** paper gives an overview about different numerical approaches to simulate uplift induced by flooding abandoned underground mines,including three different hydraulic conditions,considering both unconfined and confined water *** basic simulation schemes using 1-dimensional rock column models verified by analytical solutions demonstrate these *** results reveal that flooding induced uplift is mainly related to the pore pressure in the mine *** parameter study documents that height and stiffness of the mine goaf have the strongest influence on maximum surface uplift.

关键词： Surface uplift Abandoned mine flooding Numerical simulation Analytical solution Parameter sensitivity

Low-energy ion channeling in nanocubes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2023年第1期16卷 1522-1526页

作者： Shiva Choupanian Wolfhard Möller martin Seyring Carsten Ronning Institute of Solid State Physics Friedrich Schiller University JenaMax-Wien-Platz 107743 JenaGermany Helmholtz-Zentrum Dresden-Rossendorf Bautzner Landstraße 40001328 DresdenGermany Otto Schott Institute of Materials Research Friedrich Schiller University JenaLoebdergraben 3207743 JenaGermany

Focused ion beam(FIB)processing with low-energy ions has become a standard technique for the manipulation of *** underlying ion beam effects that deviate from conventional high-energy ion irradiation of bulk systems are considered today;however,ion channeling with its consequence of significant deeper penetration depth has been only theoretically investigated in this *** present here an experimental approach to determine the channeling of low-energy ions in crystalline nanoparticles by measuring the sputter yield derived from scanning electron microscopy(SeM)images taken after irradiation under various incident ion *** maps of 30 and 20 keV Ga+ions in Ag nanocubes have been identified and fit well with the ***,channeling has a significant impact on the transport of energetic ions in crystals due to the large critical angle at low ion energies,thus being relevant for any ***,the obtained sputter yield clearly differs from amorphous materials;therefore,it is recommended not to rely only on,e.g.,ion distribution depths predicted by standard Monte-Carlo(MC)algorithms for amorphous materials.

关键词： ion nanostructure interaction ion channeling metallic nanoparticles focused ion beam

Wave packet dynamics of nonlinear Gazeau–Klauder coherent states of a position-dependent mass system in a Coulomb-like potential

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第6期30卷 154-163页

作者： Faustin Blaise Migueu Mercel Vubangsi martin Tchoffo Lukong Cornelius Fai Unitéde Recherche de Matière Condensée d'Électronique et de Traitement du SignalDépartement de PhysiqueFacultédes SciencesUniversitéde DschangB.P:67DschangCameroon Computational Material Science Laboratory Higher Technical Teachers'Training College BambiliUniversity of BamendaPO Box 39BamendaCameroon Centre d'Études et de Recherches en Agronomie et en Biodiversité Universitéde DschangDschangCameroon

AD = 1 position-dependent mass approach to constructing nonlinear quantum states for a modified Coulomb potential is used to generate Gazeau–Klauder coherent states. It appears that their energy eigenvalues are scaled down by the quantum number and the nonlinearity coefficient. We study the basic properties of these states, which are found to be undefined on the whole complex plane, and some details of their revival structure are discussed.

关键词： deformed Coulomb potential energy spectrum coherent states photon number distribution quantum revivals