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The push-pull principle:an electrostatic actuator concept for low distortion acoustic transducers

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Microsystems & Nanoengineering 2022年第6期8卷 181-194页

作者： Bert Kaiser Hermann A.G.Schenk Lutz Ehrig Franziska Wall Jorge M.Monsalve Sergiu Langa Michael Stolz Anton Melnikov holger conrad David Schuffenhauer Harald Schenk Fraunhofer Institute for Photonic Microsystems IPMS DresdenGermany Arioso Systems GmbH since Sep.1st 2022:BOSCH Sensortec GmbHDresdenGermany Chair of Micro and Nano Systems Brandenburg University of Technology Cottbus-SenftenbergCottbusGermany

Electrostatic actuators are of particular interest for microsystems(MEMS),and in particular for MEMS audio transducers for use in advanced true wireless *** are attractive because of their typically low electrical capacitance and because they can be fabricated from materials that are compatible with standard complementary metal-oxide semiconductor(CMOS)*** high audio performance and in particular low harmonic distortion(THD)the implementation of the push-pull principle provides strong *** an arrangement of three electrodes in a conjunct moving configuration on a beam,we demonstrate here for the first time a balanced bending actuator incarnating the push-pull principle operating at low *** first design already exhibits a harmonic distortion as low as 1.2%at 79 dB using a signal voltage of only 6 V_(p) and a constant voltage of only±10 V_(dc) in a standard acoustic measurement ***,exceeding our previously reported approach in all three key performance indications at the same *** expect that our novel electrode configurations will stimulate innovative electrostatic actuator developments for a broad range of *** this paper we report the basic theory,the fabrication and the performance of our novel actuator design acting as an audio transducer.

关键词： distortion push electrostatic

Outcomes of critically ill children with pre-existing mental health conditions

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Pediatric Investigation 2024年第2期8卷 108-116页

作者： conrad Krawiec Morgan Cash Gary Ceneviva Zizhong Tian Shouhao Zhou Neal J.Thomas Department of Pediatrics Pediatric Critical Care MedicinePenn State Hershey Children's HospitalPennsylvaniaUSA Department of Public Health Sciences Division of Biostatistics and BioinformaticsPennsylvania State University College of MedicinePennsylvaniaUSA Department of Public Health_Sciences Pennsylvania State University College of MedicinePennsylvaniaUSA

Importance:Critically ill children with pre-existing mental health conditions may have an increased risk of poor health ***:We aimed to evaluate if pre-existing mental health conditions in critically ill pediatric patients would be associated with worse clinical outcomes,compared to children with no documented mental health ***:This retrospective observational cohort study utilized the TriNetX electronic health record database of critically ill subjects aged 12-18 *** were analyzed for demographics,pre-existing conditions,diagnostic,medication,procedural codes,and ***:From a dataset of 102027 critically ill children,we analyzed 1999 subjects(284[14.2%]with a pre-existing mental health condition and 1715[85.8%]with no pre-existing mental health condition).Multivariable analysis demonstrated that death within one year was associated with the presence of pre-existing mental health conditions(odds ratio 8.97[3.48-23.15],P<0.001),even after controlling for the presence of a complex chronic ***:The present study demonstrates that the presence of pre-existing mental health conditions was associated with higher odds of death within 1 year after receiving critical ***,the confidence interval was wide and hence,the findings are *** studies with a larger sample size may be necessary to evaluate the true long-term impact of children with pre-existing mental health conditions who require critical care services.

关键词： Critical care Psychiatry Psychology Public health

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Volumetric lattice Boltzmann method for pore-scale mass diffusionadvection process in geopolymer porous structures

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2126-2136页

作者： Xiaoyu Zhang Zirui Mao Floyd W.Hilty Yulan Li Agnes Grandjean Robert Montgomery Hans-conrad zur Loye Huidan Yu Shenyang Hu Purdue University IndianapolisIN46202USA Pacific Northwest National Laboratory RichlandWA99352USA CEA DESISECDMRCUniv.MontpellierMarcouleFrance Department of Chemistry and Biochemistry University of South CarolinaColumbiaSC29208USA

Porous materials present significant advantages for absorbing radioactive isotopes in nuclear waste *** improve absorption efficiency in nuclear waste treatment,a thorough understanding of the diffusion-advection process within porous structures is essential for material *** this study,we present advancements in the volumetric lattice Boltzmann method(VLBM)for modeling and simulating pore-scale diffusion-advection of radioactive isotopes within geopolymer porous *** structures are created using the phase field method(PFM)to precisely control pore *** our VLBM approach,we introduce a concentration field of an isotope seamlessly coupled with the velocity field and solve it by the time evolution of its particle population *** address the computational intensity inherent in the coupled lattice Boltzmann equations for velocity and concentration fields,we implement graphics processing unit(GPU)*** of the developed model involves examining the flow and diffusion fields in porous ***,good agreement is observed for both the velocity field from VLBM and multiphysics object-oriented simulation environment(MOOSE),and the concentration field from VLBM and the finite difference method(FDM).Furthermore,we investigate the effects of background flow,species diffusivity,and porosity on the diffusion-advection behavior by varying the background flow velocity,diffusion coefficient,and pore volume fraction,***,all three parameters exert an influence on the diffusion-advection *** background flow and diffusivity markedly accelerate the process due to increased advection intensity and enhanced diffusion capability,***,increasing the porosity has a less significant effect,causing a slight slowdown of the diffusion-advection process due to the expanded pore *** comprehensive parametric study provides valuable insights into the kinetics of isotope

关键词： Volumetric lattice Boltzmann method(VLBM) Phase field method(PFM) Pore-scale diffusion-advection Nuclear waste treatment Porous media flow Graphics processing unit(GPU) parallelization

An Ethical Framework for the Use of AI by Revenue Authorities

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Belt and Road Initiative Tax Journal 2024年第1期 41-51页

作者： Grant Wardell-Johnson conrad Turley KPMG

The use of Al may give rise to substantial benefits but also significant risks for revenue *** paper provides a brief outline of the perceived strengths and weaknesses of Al and potential use of Al in tax *** include the use of Al in risk assessment such as the selection of taxpayers for review or audit,the detection of fraud,nearest neighbour guidance,predictive analysis,anticipating changes in behaviours,improving revenue authorities' internal efficiency including transfer pricing benchmarking,and providing support and guidance to taxpayers through *** authorities are strong candidates for the use of Al given that data is central to what they *** paper postulates more than 20principles which could form the basis of an ethical framework for revenue authorities including policies on transparency,communication,traceability,explainability,human supervision,processes for the rectification of errors,data protection,privacy and *** believe that the adoption of these policies will reduce risks to revenue authorities and build trust in tax *** also believe that sharing best practices amongst revenue authorities should be a clear BRITACOM initiative consistent with its aims and objectives.

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The Role and Place of Artificial Neural Network Architectures Structural Redundancy in the Input Data Prototypes and Generalization Development

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Journal of Computer and Communications 2024年第7期12卷 1-11页

作者： conrad Onésime Oboulhas Tsahat Ngoulou-A-Ndzeli Béranger Destin Ossibi Ecole Nationale Suprieure Polytechnique Universit Marien Ngouabi Brazzaville Republic of Congo

Neural Networks (NN) are the functional unit of Deep Learning and are known to mimic the behavior of the human brain to solve complex data-driven problems. Whenever we train our own neural networks, we need to take care of something called the generalization of the neural network. The performance of Artificial Neural Networks (ANN) mostly depends upon its generalization capability. In this paper, we propose an innovative approach to enhance the generalization capability of artificial neural networks (ANN) using structural redundancy. A novel perspective on handling input data prototypes and their impact on the development of generalization, which could improve to ANN architectures accuracy and reliability is described.

关键词： Multilayer Neural Network Multidimensional Nonlinear Interpolation Generalization by Similarity Artificial Intelligence Prototype Development

Application of the N + 2 Transversal Network Method to the Study of a Coupled Resonator Filter

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Open Journal of Applied Sciences 2024年第6期14卷 1412-1424页

作者： Charmolavy Goslavy Lionel Nkouka Moukengue conrad Onésime Oboulhas Tsahat Haroun Abba Labane Barol Mafouna Kiminou Achille Makouka Electrical and Electronic Engineering Laboratory ENSP Marien Ngouabi University Brazzaville Congo Electrical Engineering Research Laboratory Polytechnic University of Mongo Mongo Tchad

This paper presents a new approach to synthesize admittance function polynomials and coupling matrices for coupled resonator filters. The N + 2 transversal network method is applied to study a coupled resonator filter. This method allowed us to determine the polynomials of the reflection and transmission coefficients. A study is made for a 4 poles filter with 2 transmission zeros between the N + 2 transversal network method and the one found in the literature. A MATLAB code was designed for the numerical simulation of these coefficients for the 6, 8, and 10 pole filter with 4 transmission zeros.

关键词： Resonator Filter Coupling Matrix Transmission Zero Transversal Network Method

Importance of hydrogenotrophic, aceticlastic and methylotrophic methanogenesis for methane production in terrestrial, aquatic and other anoxic environments: A mini review

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Pedosphere 2020年第1期30卷 25-39页

作者： Ralf conrad Max Planck Institute for Terrestrial Microbiology Karl-von-Frisch-Str.10Marburg 35043(Germany)

Microbial methanogenesis is a major source of the greenhouse gas methane(CH4).It is the final step in the anaerobic degradation of organic matter when inorganic electron acceptors such as nitrate,ferric iron,or sulfate have been *** of this degradation pathway is important for the creation of mechanistic models,prediction of future CH4 emission scenarios,and development of mitigation *** most anoxic environments,CH4 is produced from either acetate(aceticlastic methanogenesis)or hydrogen(H2)plus carbon dioxide(CO2)(hydrogenotrophic methanogenesis).Hydrogen can be replaced by other CO2-type methanogenesis,using formate,carbon monoxide(CO),or alcohols as *** ratio of these two pathways is tightly constrained by the stoichiometry of conversion *** the degradation of organic matter is complete(e.g.,degradation of straw in rice paddies),then fermentation eventually results in production of acetate and H2 at a ratio of>67%aceticlastic and<33%hydrogenotrophic ***,acetate production can be favored when heterotrophic or chemolithotrophic acetogenesis is enhanced,and H2 production can be favored when syntrophic acetate oxidation is *** typically occurs at low and elevated temperatures,***,temperature can strongly influence the methanogenic pathway,which may range from 100%aceticlastic methanogenesis at low temperatures to 100%hydrogenotrophic methanogenesis at high ***,if the degradation of organic matter is not complete(e.g.,degradation of soil organic matter),the stoichiometry of fermentation is not tightly constrained,resulting,for example,in the preferential production of H2,followed by hydrogenotrophic *** production of CH4 by either aceticlastic or hydrogenotrophic methanogenesis can also happen if one of the methanogenic substrates is not consumed by methanogens but is,instead,accumulated,volatilized,or utilized *** methano

关键词： electron acceptor fermentation methanogenic pathway organic matter degradation pH soil microbial community temperature Wood-Ljungdahl pathway

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The origin of herbivory on land： Initial patterns of plant tissue consumption by arthropods

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Insect Science 2007年第4期14卷 259-275页

作者： conrad LABANDEIRA DepartmentofPaleobiology NationalMuseumofNaturalHistorySmithsonianInstitutionWashingtonDCandDepartmentofEntomologyUniversityofMarylandCollegeParkMarylandUSA

The early fossil record of terrestrial arthropod herbivory consists of two pulses. The first pulse was concentrated during the latest Silurian to Early Devonian （417 to 403 Ma）, and consists of the earliest evidence for consumption of sporangia and stems （and limited fungivore borings）. Herbivorization of most of these tissues was rapid, representing 0 to 20 million-year （m.y.） lags from the earliest occurrences of these organs in the fossil record to their initial consumption （Phase 1）. For approximately the next 75 m.y., there was a second, more histologically varied origination and expansion of roots, leaves, wood and seeds, whose earliest evidence for herbivorization occurred from the Middle-Late Mississippian boundary to the Middle Pennsylvanian （327 to 309 Ma）. The appearance of this second herbivory pulse during the later Paleozoic （Phase 2） is accompanied by major lags of 98 to 54 m.y. between times of appearance of each of the four organ and tissue types and their subsequent herbivory. Both pulses provide a context for three emerging questions. First is an explanation for the contrast between the near instantaneous consumption of plant tissues during Phase 1, versus the exceptionally long lags between the earliest occurrences of plant tissues and their subsequent herbivorization during Phase 2. Second is the identity of arthropod herbivores for both phases. Third is the cause behind the overwhelming targeting of seed-fern plant hosts during Phase 2. Regardless of the answers to these questions, the trace fossil record of plant-arthropod associations provides primary ecological data that remain unaddressed by the body-fossil record alone.

关键词： herbivory ecological lag Devonian Carboniferous arthropod plant-insectinteractions wood boring seed predation folivory fecal pellet response tissue sporangia,roots stems

Compressibility of fine-grained soils subjected to closed-system freezing and thaw consolidation

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Mining Science and Technology 2009年第5期19卷 631-635页

作者： BOLEY conrad Institute for Soil Mechanics and Geotechnical Engineering University of the Bundeswehr Munich

In order to investigate the effects of freezing and thawing on the compressibility of fine-grained soils, freezing and thawing tests and subsequent compression tests with fine-grained soils in an oedometer were carried out. During the freezing, a part of the soils is loosened and another part is over-consolidated under the freezing pressure σE. The compression curves after the freezing and thaw consolidation are neither different from the normal consolidation curve nor from the rebound curve of an unfrozen soil, until the consolidation pressure σz = σE is arrived. Based on the experimental results, a theoretical model has been devel- oped to predict the frost heaves, the thaw-settlements and the compressive deformations of fine-grained soils after the thaw consolidation. The theoretical results are very close to the experimental results.

关键词： ice lens frost heave thaw settlement compressibility

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