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171.
The elastodynamic super-Rayleigh/subseismic indentation paradox is examined in this paper. Both the Craggs/Roberts steady-state problem and the Robinson/Thompson transient problem are reconsidered. Certain features of these solutions are discussed from a new point of view, by considering asymptotics at the end of the contact region, the influence of contact inequalities, energetics of the process and existence/uniqueness. 相似文献
172.
H. G. Georgiadis G. A. Papadopoulos 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1988,39(4):573-578
The stress intensity factor at the tip of a semi-infinite crack in an orthotropic infinite strip was determined. Clamped strip boundaries were considered. 相似文献
173.
Marios C. Angelides Georgios I. Doukidis 《The Journal of the Operational Research Society》1990,41(6):491-503
Intelligent tutoring systems (ITS) have recently found a wide range of potential applications across a multitude of disciplines and subject areas. This paper investigates the suitability and feasibility of developing ITS in the general context of OR as well as in a specific OR activity, simulation. It also examines how a current teaching aid for simulation model debugging can be transformed into an ITS and proposes a specification for the transformation process. The paper concludes that ITS could be useful in OR either for use as prime training systems or integrated in existing OR teaching packages. However, the field of ITS is in its infancy and development efforts are likely to be labour-intensive. 相似文献
174.
A. P. Georgiadis L. von Gerdtell G. Dehmelt D. Sträter R. N. Ahmad-Bitar P. von Brentano 《Zeitschrift für Physik A Hadrons and Nuclei》1981,300(4):277-279
The delayed fluorescence of the soft X-ray (1s-2p) transition was observed for H-like ions (O7+ and F8+) between 1.3 ns and 20 ns decay time after beam-foil excitation. The delayed X-ray fluorescence was found to decay with at Δ power law time dependence. The non-exponential decay is attributed to cascading through higher lying states. We found thatΔ 0=1.40±0.08 andΔ F =1.44±0.02 for H-like oxygen and fluorine, respectively. Present results are in fair agreement with the previously reported exponent,Δ 0=1.5, measured over 3 ns after excitation. 相似文献
175.
Summary During the warm months, the whole area surrounding Ravenna's petrochemical plant, which is about 5 km inshore of the northern
Adriatic coast (Po Valley region), is subject to photochemical reactions producing high values of ozone concentration. The
transport offshore of oxidants' precursors by the land breeze, photochemical reactions and subsequent transport inshore of
oxidants by the sea breeze, may cause high concentrations of ozone along the coast up until the late evening. Similar phenomena
have already been observed in other coastal regions. Classifying the ozone data into days with different circulations, the
following can be seen: on days with W or NW circulation, a regular diurnal variation of ozone correlated with solar radiation
is found; with winds from E or SE, the ozone variations are irregular and ozone concentrations can maintain high levels ((40÷70)
p.p.b.) even during the nightime. This is a report of the results of several field measurements aimed at showing the ozone
production and destruction processes, as well as its recirculation mechanisms under breeze conditions.
Paper presented at the 1o Congresso del Gruppo Nazionale per la Fisica dell'Atmosfera e dell'Oceano, June 19–22, 1984, Rome. 相似文献
176.
Serkos A. Haroutounian Minas P. Georgiadis Moschos G. Polissiou 《Journal of heterocyclic chemistry》1989,26(5):1283-1287
The stereochemical aspects of the Bucherer-Bergs reaction and a modified Strecker reaction on tetrahydro-2H-pyran-3-one derivatives have been studied in details through the use of several nmr techniques. It was found that, in both reactions, the orientation of the substituents introduced on C-3 of the pyran ring, depends from the number and nature of the substituents on the neighbouring C-2 atom. 相似文献
177.
Subwavelength features in conjunction with light‐guiding structures have gained significant interest in recent decades due to their wide range of applications to particle and atom trapping. Lately, the focus of particle trapping has shifted from the microscale to the nanoscale. This few orders of magnitude change is driven, in part, by the needs of life scientists who wish to better manipulate smaller biological samples. Devices with subwavelength features are excellent platforms for shaping local electric fields for this purpose. A major factor that inhibits the manipulation of submicrometer particles is the diffraction‐limited spot size of free‐space laser beams. As a result, technologies that can circumvent this limit are highly desirable. This review covers some of the more significant advances in the field, from the earliest attempts at trapping using focused Gaussian beams, to more sophisticated hybrid plasmonic/metamaterial structures. In particular, examples of emerging optical trapping configurations are presented.