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Electron–plasmon and electron–magnon scattering in ferromagnets from first principles by combining GW and GT self-energies

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npj Computational Materials 2021年第1期7卷 1619-1632页

作者： Dmitrii Nabok stefan Blügel Christoph Friedrich Peter Grünberg Institut and Institut for Advanced Simulation Forschungszentrum JülichJülich 52425Germany

This work combines two powerful self-energy techniques:the well-known GW method and a self-energy recently developed by us that describes renormalization effects caused by the scattering of electrons with magnons and Stoner *** GT selfenergy,which is fully k-dependent and contains infinitely many spin-flip ladder diagrams,was shown to have a profound impact on the electronic band structure of Fe,Co,and *** the present work,we refine the method by combining GT with the GW *** resulting GWT spectral functions exhibit strong lifetime effects and emergent dispersion *** are in an overall better agreement with experimental spectra than those obtained with GW or GT alone,even showing partial improvements over local-spin-density approximation dynamical mean-field *** performed analysis provides a basis for applying the GWT technique to a wider class of magnetic materials.

关键词： materials theory infinitely

A COMPARATIVE STUDY ON INVOLVEMENT OF tPA ACTIVITY IN OVULATION INDUCED BY hCG AND GnRH AGONIST IN HYPOPHYSECTOMIZED RATS

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Science China Chemistry 1991年第10期34卷 1215-1224页

作者：刘以训冯强 CAjANDER stefan Laboratory of Reproductive Biology and Department of Endocrinology Institute of Zoology Academia Sinica Beijing 100080 PRC Department of Pathology Ume UniversityS-90187UmeSweden

A GnRH agonist (5-50 μg) is capable of inducing ovulation in PMSG-primed hypophy-sectomized immature rats, as is the case in hCG-induced ovulation, but 2-4 h earlier than hCG. GnRH-induced ovulation is effectively blocked by the concomitant administration of the GnRH-antagonist which failed to interfere with hCG-induced ovulation, indicating that GnRH and its agonists do not share a receptor with LH/hCG. Like hCG, GnRH is also capable of inducing tissue type (tPA), but not urokinase type (uPA) PA. The plasminogen activator activity in ovarian homogenates and the granulosa and theca-interstitial cells increase in a time-dependent manner, reaching maximum levels just prior to ovulation. Similar to hCG, GnRH also increases tPA activity in cumulus-oocyte complexes in a time-dependent fashion.

关键词： hCG GnRH agonist hypophysectomized rat ovulation tPA.

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Machine Learning for heat radiation modeling of bi-and polydisperse particle systems including walls

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Particuology 2023年第3期74卷 119-140页

作者： josef Tausendschön Gero Stöckl stefan Radl Institute of Process and Particle Engineering Graz University of TechnologyInffeldgasse 13/III8010GrazAustria

We investigated the ability of four popular Machine Learning methods i.e.,Deep Neural Networks(DNNs),Random Forest-based regressors(RFRs),Extreme Gradient Boosting-based regressors(XGBs),and stacked ensembles of DNNs,to model the radiative heat transfer based on view factors in bi-and polydisperse particle beds including *** training and analyzing the predictive capability of each method,an adjustment of markers used in monodisperse systems,as well as an evaluation of new markers was *** the basis of our dataset that considers a wide range of particle radii ratios,system sizes,particle volume fractions,as well as different particle-species volume fractions,we found that(i)the addition of particle size information allows the transition from monodisperse to bi-and polydisperse beds,and(ii)the addition of particle volume fraction information as the fourth marker leads to very accurate *** terms of the overall performance,DNNs and RFRs should be preferred compared to the other two *** particle-particle view factors,DNN and RFR are on par,while for particle-wall the RFR is *** demonstrate that DNNs and RFRs can be built to meet or even exceed the prediction quality standards achieved in a monodisperse system.

关键词： Discrete element method(DEM) Heat radiation modeling Machine learning View factors Wall radiation Polydisperse particles

Development and validation of a transient simulation model of a full-scale PCM embedded radiant chilled ceiling

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Building Simulation 2023年第6期16卷 813-829页

作者： Seyedmostafa Mousavi Behzad Rismanchi stefan Brey Lu Aye Renewable Energy and Energy Efficiency Group Department of Infrastructure EngineeringFaculty of Engineering and Information Technology(FEIT)The University of MelbourneMelbourneVIC3010Australia InvAus Pty Ltd. MelbourneVIC3000Australia

The recent significant rise in space cooling energy demand due to the massive use of air-conditioning systems has adversely changed buildings’energy use patterns *** updated energy technology perspectives highlight the need for innovative cooling systems to address this growing cooling *** change material embedded radiant chilled ceiling(PCM-RCC)has lately acquired popularity as they offer more efficient space cooling together with further demand-side *** advancements in PCM-RCC applications have increased the necessity for reliable simulation models to assist professionals in identifying improved designs and operating *** this study,a transient simulation model of PCM-RCC has been developed and validated using measured data in a full-scale test cabin equipped with newly developed PCM ceiling *** model,developed in the TRNSYS simulation studio,includes Type 399 that uses the Crank-Nicolson algorithm coupled with the enthalpy function to solve transient heat transfer in PCM ceiling *** developed model is validated in both free-running and active operation modes,and its quality is then evaluated using several validation *** results obtained in multiple operating scenarios confirm that the model simulates the transient behaviour of the PCM-RCC system with an accuracy within±10%.Aided by this validated model,which offers the user detailed flexibilities in the system design and its associated operating schemas,PCM-RCC’s potentials regarding peak load shifting,energy savings,and enhanced thermal comfort can be investigated more reliably.

关键词： phase change material(PCM) radiant cooling ceiling panel modelling and simulation validation

Speciation in nanosecond laser ablation of zinc in water

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Science China(Physics,Mechanics & Astronomy) 2022年第7期65卷 90-98页

作者： stefan Reich Yannis Klügl Anna Ziefuss RenéStreubel jorg Gottlicher Anton Plech Institute for Photon Science and Synchrotron Radiation Karlsruhe Institute of TechnologyKarlsruhe D-76021Germany Department of Technical ChemistryⅠand Center for Nanointegration Duisburg-Essen University of Duisburg-EssenEssen D-45141Germany Fraunhofer Institute for High-Speed Dynamics Ernst-Mach-Institute(EMI)Freiburg 79104Germany

In situ experimental methods have been applied to resolve mass flow and chemical speciation in the pulsed laser ablation of zinc in water. The chemical speciation has been resolved by time-resolved μ-X-ray absorption spectroscopy and mapped onto the macroscopic mass flow during material ejection from the metallic target and bubble dynamics of evaporated water. Large particles and agglomerates have been detected via dark-field X-ray imaging with a Shack-Hartmann sensor. The characteristic of the dynamics is that the vapor bubble is nearly homogeneously filled with ablated material. This persists during bubble collapse,which means that the ablated particles are captured and retracted towards the target. Limited mass escape is indicated by the X-ray absorption signal. Importantly, the near-edge structure at the Zn-K;transition delivers information on the chemical state of the ejected material. It clearly confirms that oxidation is not present within the bubble phase and the following sub-millisecond time scale. The oxidation proceeds on Zn nanoparticles in suspension on a second to minute course. Within the first microseconds,a Zn atom phase is detected that resembles Zn vapor. The addition of either reductive NaBH;or oxidative HAuCl;to the water phase influences the quantity of the atom contribution moderately, but does not influence the initial atom phase. Such behavior must be understood in terms of the nanosecond pulse excitation. After ejected material and a plasma is formed within the pulse duration of 7 ns the laser is able to further heat the ejecta and transform it partly into vapor. Correspondingly, the coupling of energy into the ablation zone as followed by plasma intensity and bubble size follows a threshold behavior as a function of laser fluence, marking the onset of laser-plasma heating. The reaction conditions inside the bubble are probably reductive due to the concomitant formation of excess hydrogen.

关键词： laser ablation in liquids elemental speciation X-ray absorption spectroscopy oxidation zinc oxide nanoparticles

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Online Induction of Probabilistic Real-Time Automata

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journal of Computer Science & Technology 2014年第3期29卷 345-360页

作者： jana Schmidt stefan Kramer Technische Universitt Mnchen Institut fr Informatik/I12Boltzmannstr. 385748 Garching b. MnchenGermany johannes Gutenberg-Universitt Mainz Institute for Computer ScienceStaudingerweg 955128 MainzGermany

The probabilistic real-time automaton （PRTA） is a representation of dynamic processes arising in the sciences and industry. Currently, the induction of automata is divided into two steps： the creation of the prefix tree acceptor （PTA） and the merge procedure based on clustering of the states. These two steps can be very time intensive when a PRTA is to be induced for massive or even unbounded datasets. The latter one can be efficiently processed, as there exist scalable online clustering algorithms. However, the creation of the PTA still can be very time consuming. To overcome this problem, we propose a genuine online PRTA induction approach that incorporates new instances by first collapsing them and then using a maximum frequent pattern based clustering. The approach is tested against a predefined synthetic automaton and real world datasets, for which the approach is scalable and stable. Moreover, we present a broad evaluation on a real world disease group dataset that shows the applicability of such a model to the analysis of medical processes.

关键词： probabilistic real-time automata online induction maximum frequent pattern based clustering

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Quantitative spatiotemporal impact of dynamic population density changes on the COVID-19 pandemic in China’s mainland

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Geo-Spatial Information Science 2023年第4期26卷 642-663页

作者： Guangyuan Zhang stefan Poslad Yonglei Fan Xiaoping Rui IoT Laboratory School of Electronic Engineering and Computer ScienceQueen Mary University of LondonLondonUK School of Earth Sciences and Engineering Hohai UniversityNanjingChina

The coronavirus disease 2019(COVID-19)and its mutant viruses are still wreaking global havoc over the last two years,but the impact of human activity on the transmission of the pandemic is difficult to *** human dynamic spatiotemporal distribution can help in our understanding of how to mitigate COVID-19 spread,which can help in maintaining urban health within a county and between counties within a *** distribution can be computed using the Volunteered Geographic Information(VGI)of the citizens in conjunction with other variables,such as climatic conditions,and used to analyze how human’s daily density distribution quantitatively affects COVID-19 *** on the estimated population density,when the population density increases daily by 1 person/km^(2) in a county or prefectural-level administrative unit with an average size of 26,000 km^(2),the county would have an additional 3.6 confirmed cases and 0.054 death cases after 5 days,which is the illness onset time for a new COVID-19 *** 14 days,which is the maximum incubation period of the COVID-19 virus,there would be 5 new confirmed cases and 0.092 death ***,in neighboring regions,there can be 0.96 fewer people infected with COVID-19 on average per day as a result of strong intervention of local and neighboring *** primary innovation and contribution are that this is the first quantitative assessment of the impacts of dynamic population density on the COVID-19 ***,the direct and indirect effects of the impact are estimated using spatial panel *** models that control the unobserved factors improve the reliability of the estimation,as validated by random experiments and the use of the Baidu migration dataset.

关键词： COVID-19 Geographic Information Systems(GIS) panel data Spatial Durbin Model(SDM)

Sensitivity analysis of sediment flux derived by laser diffraction and acoustic backscatter within a reservoir

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International journal of Sediment Research 2018年第1期33卷 18-26页

作者： stefan Haun Laura Lizano Institute for Modelling Hydraulic and Environmental Systems University of Stuttgart Department of Hydraulic and Environmental Engineering Norwegian University of Science and Technology Ministry of Environment and Energy

A combination of two indirect methods to measure sediment flux is presented in this study to evaluate suspended sediment transport in a hydropower reservoir. The acoustic backscatter signal(ABS)from an Acoustic Doppler Current Profiler(ADCP) is therefore applied in pre-defined transects within the reservoir in combination with a Laser In-Situ Scattering Transmissometry-stream lined device(LISSTSL). The stationary LISST-SL derived suspended sediment concentration(SSC) measurements are used to calibrate the ABS. From the LISST-SL measurements a time series of SSC is obtained. This enables, in addition, a comprehensive data analysis to evaluate the influence of natural fluctuations of the SSC on the calculated sediment flux, which should be taken into account when assessing sediment transport. Furthermore SSC measurements are done with the LISST-SL close to the reservoir bed. In areas close to the bed no information regarding the ABS is available from the ADCP measurements due to the side-lobe interference. In various studies the information from the last three valid cells is used for ***, as result of a comparison of the LISST-SL measurements with extrapolated SSC values from the ADCP measurements it can be seen that, especially in deep reservoirs, this method has to be adapted to the in-situ conditions.

关键词： Reservoir Suspended sediment concentrations Sediment flux Laser diffraction Acoustic backscatter signal

Less workplace parking with fully autonomous vehicles?

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journal of Intelligent and Connected Vehicles 2022年第3期5卷 283-301页

作者： stefan Tscharaktschiew Felix Reimann Institute of Transport and Economics Technische Universität DresdenDresdenGermany

Purpose–Recent studies on commuter parking in an age of fully autonomous vehicles(FAVs)suggest,that the number of parking spaces close to the workplace demanded by commuters will decline because of the capability of FAVs to return home,to seek out(free)parking elsewhere or just *** would be good news because,as of today,parking is one of the largest consumers of urban land and is associated with substantial costs to *** of the studies,however,is concerned with the special case of employer-provided parking,although workplace parking is a widespread phenomenon and,in many instances,the dominant form of commuter *** purpose of this paper is to analyze whether commuter parking will decline with the advent of self-driving cars when parking is provided by the ***/methodology/approach–This study looks at commuter parking from the perspective of both the employer and the employee because in the case of employer-provided parking,the firm’s decision to offer a parking space and the incentive of employees to accept that offer are closely interrelated because of the fringe benefit character of workplace *** study develops an economic equilibrium model that explicitly maps the employer–employee relationship,considering the treatment of parking provision and parking policy in the income tax code and accounting for adverse effects from commuting,parking and public *** study determines the market level of employer-provided parking in the absence and presence of FAVs and identifies the factors that drive the *** study then approximates the magnitude of each factor,relying on recent(first)empirical evidence on the impacts of ***–This paper’s analysis suggests that as long as distortive(tax)policy favors employer-provided parking,FAVs are no guarantee to end up with less commuter ***/value–This study’s findings imply that in a world of self-driving cars,policy intervention related to work comm

关键词： Autonomous vehicles Employer-provided parking Fringe benefit Self-driving cars Transport policy