Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "Teh, K. H." wg kryterium: Autor


Wyświetlanie 1-3 z 3
Tytuł:
Propagation in dielectric rectangular waveguides
Autorzy:
Yeap, K. H.
Teh, K. H.
Yeong, K. C.
Lai, K. C.
Loh, M. C.
Powiązania:
https://bibliotekanauki.pl/articles/173566.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
dielectric rectangular waveguide
transverse wave numbers
attenuation coefficient
surface impedance
propagation constant
fundamental mode
Opis:
We present a fundamental and accurate approach to compute the attenuation of electromagnetic waves propagating in dielectric rectangular waveguides. The transverse wave numbers are first obtained as roots of a set of transcendental equations developed by matching the fields with the surface impedance of the wall. The propagation constant is found by substituting the values of transverse wave numbers into the dispersion relation. We have examined the validity of our model by comparing the computed results with those obtained from Marcatili’s equations and the finite element method. In our results, it is shown that the fundamental mode is identical with that found in a perfectly conducting waveguide. Our analysis also shows that a hollow waveguide is found to have much lower attenuation than its dielectric counterparts. Since the cutoff frequency is usually affected by the constitutive properties of the dielectric medium, for a waveguide designed for wave with the same cutoff frequency, hollow waveguides turn out to be relatively larger in size.
Źródło:
Optica Applicata; 2016, 46, 2; 317-330
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rotating orbits of pendulum in stochastic excitation
Autorzy:
Teh, S.-H.
Woo, K.-C.
Demrdash, H.
Powiązania:
https://bibliotekanauki.pl/articles/280676.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
parametric pendulum
stochastic excitation
energy harvesting
Opis:
A method to extract energy from an excitation which is stochastic in nature is presented. The experimental rig comprises a pendulum, and a vertical excitation is provided by a solenoid. The control input assumed in the form of a direct current motor, and another motor, used in reverse, acts as a generator. The stochastic excitation has been achieved by varying the time interval between switching the RLC circuit on and off according to a random distribution. Such non-linear vertical excitations act on an oscillatory system from which a pendulum is pivoted. The Pierson-Moskowitz spectrum has been chosen as the random distribution while an inverse transform technique has been used for generation of the random excitation signal in LabVIEW environment. Moreover, a bang-bang control algorithm has been implemented to facilitate rotational motion of the pendulum. Experimental observations have been made for various noise levels of vertical excitations, and their implication on energy generation has been discussed. A positive amount of energy has been extracted for a minimal amount of the control input.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 3; 717-730
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Supercontinuum fiber laser source for water quality and heavy metals detection
Autorzy:
Teh, P. C.
Ho, Y. H.
Ong, C. E.
Lee, S. C.
Lo, P. K.
Lai, K. C.
Yeap, K. H.
Loh, S. H.
Teh, P. S.
Tey, K. L.
Powiązania:
https://bibliotekanauki.pl/articles/174135.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
supercontinuum generation
master oscillator power amplifier
nonlinear optics
transmittance measurement
heavy metal contaminants
Opis:
We report a compact, all fiber, 150 ps fiber master oscillator power amplifier operating at 1064 nm that has the ability of producing a maximum average output power of 2.16 W with peak power as high as 10 kW. The output from the master oscillator power amplifier is spliced with a highly nonlinear photonic crystal fiber, generating a supercontinuum with an average power of 250 mW at repetition rate of 1 MHz and spectrum bandwidth spanning from 600 to 1700 nm. The developed supercontinuum system is used to detect the presence of heavy metal contaminants in water by a simple light transmittance method to ensure that the water is free from heavy metal contaminants and safe for consumption. The supercontinuum laser source was shone onto a water sample with a detector placed at another end in order to measure the transmitted supercontinuum light. By measuring the amount of light attenuated at particular wavelength, the concentration of heavy metal contaminants present in the water sample could be determined.
Źródło:
Optica Applicata; 2017, 47, 3; 445-456
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

    Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies