29,719 research outputs found
La flore algale et sa distribution dans la région du fleuve Han, Corée
No full textThe 208 taxons of algae were identified from the Han river in Korea from april 1979 to june 1981. The quantitative remarks on plankton and periphyton dynamics along the Han River show a great ecological difference between the survey sites.208 taxons d'algues sont identifiés pour le fleuve Han, Corée du Sud, du mois d'avril 1979 au mois de juin 1981. L'étude quantitative sur la dynamique du plancton et du périphyton, le long du fleuve, montre une grande différence écologique entre les stations d'étude.Yi Beom-Jun. La flore algale et sa distribution dans la région du fleuve Han, Corée. In: Bulletin mensuel de la Société linnéenne de Lyon, 52ᵉ année, n°3, mars 1983. pp. 73-81
Incremental Nonlinear Stability Analysis of Stochastic Systems Perturbed by L\'{e}vy Noise
No full textWe present a theoretical framework for characterizing incremental stability
of nonlinear stochastic systems perturbed by compound Poisson shot noise and
finite-measure L\'{e}vy noise. For each noise type, we compare trajectories of
the perturbed system with distinct noise sample paths against trajectories of
the nominal, unperturbed system. We show that for a finite number of jumps
arising from the noise process, the mean-squared error between the trajectories
exponentially converge towards a bounded error ball across a finite interval of
time under practical boundedness assumptions. The convergence rate for shot
noise systems is the same as the exponentially-stable nominal system, but with
a tradeoff between the parameters of the shot noise process and the size of the
error ball. The convergence rate and the error ball for the L\'{e}vy noise
system are shown to be nearly direct sums of the respective quantities for the
shot and white noise systems separately, a result which is analogous to the
L\'{e}vy-Khintchine theorem. We demonstrate our results using several numerical
case studies.Comment: To be published. See
https://onlinelibrary.wiley.com/doi/10.1002/rnc.6216 for final versio
An alternative method for smartphone input using AR markers
No full textAbstractAs smartphones came into wide use recently, it has become increasingly popular not only among young people, but among middle-aged people as well. Most smartphones adopt capacitive full touch screen, so touch commands are made by fingers unlike the PDAs in the past that use touch pens. In this case, a significant portion of the smartphone’s screen is blocked by the finger so it is impossible to see the screens around the finger touching the screen; this causes difficulties in making precise inputs. To solve this problem, this research proposes a method of using simple AR markers to improve the interface of smartphones. A marker is placed in front of the smartphone camera. Then, the camera image of the marker is analyzed to determine the position of the marker as the position of the mouse cursor. This method can enable click, double-click, drag-and-drop used in PCs as well as touch, slide, long-touch-input in smartphones. Through this research, smartphone inputs can be made more precise and simple, and show the possibility of the application of a new concept of smartphone interface
Microstructural changes during superplastic deformation of Fe-24Cr-7Ni-3Mo-0.14N duplex stainless steel
No full textThe superplasticity of Fe-24Cr-7Ni-3Mo-0.14N duplex stainless steel after solution treatment at 1350 degrees C followed by 90% cold rolling was investigated at 850 degrees C with a strain rate ranging from 10(-3) to 10(-1) s(-1). The microstructure of duplex stainless steel consists of matrix gamma phase having low angle boundaries and sigma phase as second phase particles before the deformation at 850 degrees C. The constituent phases in the duplex stainless steel were found to be changed following alpha --> alpha + gamma --> alpha + gamma + sigma --> gamma + sigma through phase transformation during the deformation at 850 degrees C. A maximum elongation of 750% was obtained at 850 degrees C with strain rate of 3.16 x 10(-3) s(-1). The low angle grain boundaries were changed into high angle grain boundaries by dynamic recrystallization of gamma phase at an early stage of deformation. The dislocation density within matrix gamma grains was low and a significant strain-induced grain growth was observed during the deformation. The misorientation angles between the neighboring gamma grains increased with increasing strain; thus the low angle grain boundaries were transformed into high angle grain boundaries suitable for sliding by the dynamic recrystallization during the deformation. The grain boundary sliding assisted by dynamic recrystallization is considered a controlling mechanism for superplastic deformation at 850 degrees C. (C) 1999 Elsevier Science S.A. All rights reserved
The Effects of Deformation Twins and Strain-Induced Epsilon-Martensite on Mechanical-Properties of an Fe-32Mn-12Cr-0,4C Cryogenic alloy
No full text
Phenomena and mechanism on superplasticity of duplex stainless steels
No full textThe superplasticity of Fe-24Cr-7Ni-3Mo-0.14N duplex stainless steel after being solution treated at 1350 degrees C followed by 90% cold rolling was investigated at 850 degrees C with a strain rate ranging from 10(-3)-10(-1)s(-1). The microstructure of duplex stainless steel consists of a matrix gamma phase having low angle grain boundaries and a sigma phase as second phase particles before the deformation at 850 degrees C. It is well known that the constituent phases in duplex stainless steel is changed following alpha-->alpha+gamma-->alpha+gamma+sigma-->gamma+sigma through phase transformation during deformation at 850 degrees C. The final microstructure of duplex stainless steel consisted of 70 vol.% of gamma and 30 vol.% of the sigma phase. A maximum elongation of 750% was obtained at 850 degrees C with a strain rate of 3.16x10(-3)s(-1). The dislocation density within matrix gamma grains was low and a significant strain-induced grain growth was observed during the deformation. The misorientation angles between the neighboring gamma grains increased as the strain increased, thus the low angle grain boundaries were transformed into high angle grain boundaries suitable for sliding by dynamic recrystallization during the deformation at 850 degrees C. The grain boundary sliding assisted by dynamic recrystallization is considered to be a controlling mechanism for superplastic deformation at 850 degrees C
Development of a thermal-hydraulic analysis code for annular fuel assemblies
No full textA thermal-hydraulic analysis code which is capable of modeling both internally and externally cooled annular fuel pins was developed. The coolant flow distribution in the annular fuel-based assemblies is adjusted by a pressure drop model allowing for conditions such as non-equal velocity and non-saturated phases. The heat transfer fraction is determined by the ratio of cross-sectional areas distinguished by the radius at which the first derivative of the temperature within the annular fuel equals zero. The code predictions have been compared with calculations from Korea Atomic Energy Research Institute (KAERI) and MIT. The heat transfer fraction difference between the code and RELAP was about 3.9%, and the Departure from Nucleate Boiling Ratio (DNBR) prediction of the code agreed well with the MIT's result in the region below 3 m. For the application of the code, thermal-hydraulics of thorium-based fuel assemblies loaded with annular seed pins were compared with those of the existing thorium-based assemblies. The pressure drop in the assembly generally increased in the case of annular fuel due to the larger wetted perimeter. In the inner subchannels of the seed pins, mass fluxes were high due to the grid form losses in the outer subchannels. About 43% of the heat generated from the seed pin flowed into the inner subchannel and the rest into the outer subchannel. The minimum DNBRs (MDNBRs) of the annular fuel-based assemblies were higher than those of the existing ones. Because interchannel mixing cannot occur in the inner subchannels, temperatures and enthalpies were higher in the inner subchannels. (C) 2003 Elsevier B.V. All rights reserved
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