1,087 research outputs found
A methodology for determining optimum microwave remote sensor parameters
There are no author-identified significant results in this report
Image synthesis for SAR system, calibration and processor design
The Point Scattering Method of simulating radar imagery rigorously models all aspects of the imaging radar phenomena. Its computational algorithms operate on a symbolic representation of the terrain test site to calculate such parameters as range, angle of incidence, resolution cell size, etc. Empirical backscatter data and elevation data are utilized to model the terrain. Additionally, the important geometrical/propagation effects such as shadow, foreshortening, layover, and local angle of incidence are rigorously treated. Applications of radar image simulation to a proposed calibrated SAR system are highlighted: soil moisture detection and vegetation discrimination
Deterministically entangling distant nitrogen-vacancy centers by a nanomechanical cantilever
We present a practical scheme by global addressing to deterministically
entangle negatively charged nitrogen-vacancy (N-V) centers in distant diamonds
using a nano-mechanical cantilever with the magnetic tips strongly coupled to
the N-V electron spins. Symmetric Dicke states are generated as an example, and
the experimental feasibility and challenge of our scheme are discussed.Comment: 5 pages, 4 figure
Vorrichtung zur Beobachtung der dreidimensionalen Bewegung von Objekten, die in einer Flüssigkeit gehalten sind
Vorrichtung zur Beobachtung der dreidimensionalen Bewegung von Objekten (2), die in einer Flüssigkeit gehalten sind und deren Bewegung abhängig ist von den in der Flüssigkeit herrschenden örtlichen Eigenschaften wie der Temperatur, der chemischen Zusammensetzung oder den Lichtverhältnissen, wobei die Vorrichtung umfasst:- eine Beobachtungkammer (5) zur Aufnahme der mit den Objekten (2) versehenen Flüssigkeit,- eine erste Belichtungseinrichtung (6) mit einer Lichtquelle (7), eingerichtet zur lokalen Änderung der Eigenschaften in der Flüssigkeit,- eine optische Aufnahmeeinheit (12), eingerichtet zur optischen Erfassung der Objekte (2) in der Flüssigkeit, dadurch gekennzeichnet,dass die erste Belichtungseinrichtung (6) eingerichtet ist, gezielt eine Lichtmenge in einer gewünschten dreidimensionalen Verteilung in die Flüssigkeit der Beobachtungskammer (5) einzubringen, wobei die Flüssigkeit Bestandteile aufweist, die bei Einwirkung von optischen Lichtstrahlen einer bestimmten Wellenlänge ihre Eigenschaften ändern unddass die optische Aufnahmeeinheit eingerichtet ist, die Bewegung der Objekte (2) räumlich zu erfassen und in entsprechende elektronische Signale umzuwandeln
The future of higher education (HE) hangs on innovating our assessment – but are we ready, willing and able?
Graduates are entering a sociotechnological world, with teaching and assessment needing to reflect that, by shifting from a ‘recall-on-paper’ to ‘do-it-for-real’. With increasing student numbers, it is not feasible to have staff-student ratios and round-the-clock availability required to provide instant feedback and ever-more interactive teaching sessions, so digital solutions are the only option. There is already growing comfort with using computers in formal assessment; however, more work is required to extend beyond performance indicators enabling digital assessments, to addressing how students apply their learning to relevant work-based scenarios. This opinion piece discusses the issues HE currently face to ensure students develop the employability skills that equip them to be proficient in the skills directly related to their degree subject but also transferable to other graduate careers. It raises possible solutions to current technological problems in developing more computer-based assessment, to enable academics to design assessments that develop the capabilities students need
Analysis of geologic terrain models for determination of optimum SAR sensor configuration and optimum information extraction for exploration of global non-renewable resources. Pilot study: Arkansas Remote Sensing Laboratory, part 1, part 2, and part 3
Computer-generated radar simulations and mathematical geologic terrain models were used to establish the optimum radar sensor operating parameters for geologic research. An initial set of mathematical geologic terrain models was created for three basic landforms and families of simulated radar images were prepared from these models for numerous interacting sensor, platform, and terrain variables. The tradeoffs between the various sensor parameters and the quantity and quality of the extractable geologic data were investigated as well as the development of automated techniques of digital SAR image analysis. Initial work on a texture analysis of SEASAT SAR imagery is reported. Computer-generated radar simulations are shown for combinations of two geologic models and three SAR angles of incidence
Gauge-Independent Kinetic Energy Densities in Meta-GGAs and Local Hybrid Calculations of Magnetizabilities
In a recent study [J. Chem. Theory Comput. 2021, 17, 1457-1468], some of us
examined the accuracy of magnetizabilities calculated with density functionals
representing the local density approximation (LDA), generalized gradient
approximation (GGA), meta-GGA (mGGA) as well as global hybrid (GH) and
range-separated (RS) hybrid functionals by assessment against accurate
reference values obtained with coupled-cluster theory with singles, doubles and
perturbative triples [CCSD(T)]. Our study was later extended to local-hybrid
(LH) functionals by Holzer et al. [J. Chem. Theory Comput. 2021, 17,
2928-2947]; in this work, we examine a larger selection of LH functionals, also
including range-separated LH (RSLH) functionals and strong-correlation LH
(scLH) functionals. Holzer et al also studied the importance of the physically
correct handling of the magnetic gauge dependence of the kinetic energy density
in mGGA calculations by comparing the Maximoff--Scuseria formulation
of used in our aforementioned study to the more physical current-density
extension derived by Dobson. In this work, we also revisit this comparison with
a larger selection of mGGA functionals. We find that the newly tested LH, RSLH
and scLH functionals outperform all the functionals considered in the previous
studies. The various LH functionals afford the seven lowest mean absolute
errors, while also showing remarkably small standard deviations and mean
errors. Most strikingly, the best two functionals are scLHs that also perform
remarkably well in cases with significant multiconfigurational character such
as the ozone molecule, which is traditionally excluded from the statistical
error evaluation due to its large errors with common density functionals.Comment: 22 pages, 1 figur
The steering gaits of sperm
Sperm are highly specialized cells, which have been subject to substantial evolutionary pressure. Whereas some sperm features are highly conserved, others have undergone major modifications. Some of these variations are driven by adaptation to mating behaviours or fitness at the organismic level. Others represent alternative solutions to the same task. Sperm must find the egg for fertilization. During this task, sperm rely on long slender appendages termed flagella that serve as sensory antennas, propellers and steering rudders. The beat of the flagellum is periodic. The resulting travelling wave generates the necessary thrust for propulsion in the fluid. Recent studies reveal that, for steering, different species rely on different fundamental features of the beat wave. Here, we discuss some examples of unity and diversity across sperm from different species with a particular emphasis on the steering mechanisms. This article is part of the Theo Murphy meeting issue ‘Unity and diversity of cilia in locomotion and transport’
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Ugi multicomponent reaction to prepare peptide–peptoid hybrid structures with diverse chemical functionalities
Monodisperse sequenced peptides and peptoids present unique nano-structures based on their self-assembled secondary and tertiary structures. However, the generation of peptide and peptoid hybrid oligomers in a sequence-defined manner via Ugi multicomponent reaction has not yet been studied. Herein, we report a synthetic strategy that enables both the modification of peptides as well as the generation of sequence-defined peptide–peptoid hybrid structures. Our synthetic methodology rests on the fusion of solid phase peptide synthesis with Ugi multicomponent reactions. We evidence that a diversity of chemical functionalities can be inserted into peptides or used in the design of peptide–peptoid hybrids exploiting a wide functional array including amines, carboxylic acids, hydrocarbons, carbohydrates as well as polymers, introducing a sequence-defined synthetic platform technology for precision peptoid hybrids
Проблемы геологии и освоения недр. Т. 2
В сборнике отражены проблемы палеонтологии, стратиграфии, тектоники, исторической и региональной геологии, минералогии, геохимии, петрологии, литологии, полезных ископаемых, металлогении, гидрогеологии, гидрогеохимии, инженерной геологии, геофизики, нефтяной геологии, геоинформационных систем в геологии, разработки нефтяных и газовых месторождений, переработки углеводородного и минерального сырья, нефтегазопромыслового оборудования, бурения нефтяных и газовых скважин, техники и технологии разведки и добычи, транспорта и хранения нефти и газа, горного дела, технологии и техники разведки месторождений полезных ископаемых, геоэкологии, гидрогеоэкологии, охраны и инженерной защиты окружающей среды, комплексного использования минерального сырья, землеустройства, экономики минерального сырья и горного права
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