Informacja

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

Wyszukujesz frazę "temperature modulation" wg kryterium: Temat


Wyświetlanie 1-7 z 7
Tytuł:
Growth and properties of ZnO films grown using pa-movpe with DMZn and N2O
Autorzy:
Nakano, T.
Nishimoto, K.
Sumiya, M.
Fuke, S.
Powiązania:
https://bibliotekanauki.pl/articles/385163.pdf
Data publikacji:
2009
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
ZnO
PA-MOVPE
epitaxial growth
DMZn
N2O
temperature modulation growth
Opis:
ZnO films were grown by plasma-assisted metal organic vapor phase epitaxy (PA-MOVPE) using dimethylzinc (DMZn) and N O gases. The crystallinity and surface morphology of ZnO films were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The crystallinity of ZnO improved (a) when the N2O flow rate was increased, because vapor phase reaction was suppressed while surface migration was enhanced, and (b) when the growth temperature was increased, because surface diffusion was enhanced. In the PA-MOVPE method with N2O gases and DMZn, both the N2O flow rate and crystal growth temperature strongly affected the crystallinity of ZnO films.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2009, 3, 4; 124-126
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrogen Detection With a Gas Sensor Array – Processing and Recognition of Dynamic Responses Using Neural Networks
Autorzy:
Gwiżdż, P.
Brudnik, A.
Zakrzewska, K.
Powiązania:
https://bibliotekanauki.pl/articles/221723.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gas sensor
sensor array
temperature modulation
dynamic response
feature extraction
neural networks
Opis:
An array consisting of four commercial gas sensors with target specifications for hydrocarbons, ammonia, alcohol, explosive gases has been constructed and tested. The sensors in the array operate in the dynamic mode upon the temperature modulation from 350°C to 500°C. Changes in the sensor operating temperature lead to distinct resistance responses affected by the gas type, its concentration and the humidity level. The measurements are performed upon various hydrogen (17-3000 ppm), methane (167-3000 ppm) and propane (167-3000 ppm) concentrations at relative humidity levels of 0-75%RH. The measured dynamic response signals are further processed with the Discrete Fourier Transform. Absolute values of the dc component and the first five harmonics of each sensor are analysed by a feed-forward back-propagation neural network. The ultimate aim of this research is to achieve a reliable hydrogen detection despite an interference of the humidity and residual gases.
Źródło:
Metrology and Measurement Systems; 2015, 22, 1; 3-12
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of modulation on heat transport by a weakly nonlinear thermal instability in the presence of applied magnetic field and internal heating
Autorzy:
Manjula, S. H.
Kiran, Palle
Narsimlu, G.
Roslan, R.
Powiązania:
https://bibliotekanauki.pl/articles/1839705.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
modulacja
pole magnetyczne
ogrzewanie
Ginzburg-Landau equation
temperature modulation
applied magnetic field
internal heating
Opis:
The present paper deals with a weakly nonlinear stability problem under an imposed time-periodic thermal modulation. The temperature has two parts: a constant part and an externally imposed time-dependent part. We focus on stationary convection using the slow time scale and quantify convective amplitude through the real Ginzburg-Landau equation (GLE). We have used the classical fourth order Runge-Kutta method to solve the real Ginzburg-Landau equation. The effect of various parameters on heat transport is discussed through GLE. It is found that heat transport analysis is controlled by suitably adjusting the frequency and amplitude of modulation. The applied magnetic field (effect of Ha) is to diminish the heat transfer in the system. Three different types of modulations thermal, gravity, and magnetic field have been compared. It is concluded that thermal modulation is more effective than gravity and magnetic modulation. The magnetic modulation stabilizes more and gravity modulation stabilizes partially than thermal modulation.
Źródło:
International Journal of Applied Mechanics and Engineering; 2020, 25, 4; 96-115
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Weakly nonlinear oscillatory convection in a viscoelastic fluid saturated porous medium with throughflow and temperature modulation
Autorzy:
Kiran, P.
Narasimhulu, Y.
Manjula, S. H.
Powiązania:
https://bibliotekanauki.pl/articles/265198.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
przepływ
modulacja temperatury
teoria nieliniowa
model Ginzburga-Landaua
throughflow
temperature modulation
weak nonlinear theory
complex Ginzburg-Landau model
Opis:
The effect of vertical throughfow and temperature modulation on a viscoelastic fluid saturated porous medium has been investigated. The amplitudes of temperature modulation at the lower and upper surfaces are considered to be very small and the disturbances are expanded in terms of power series of amplitude of convection. A weak nonlinear stability analysis has been performed for the oscillatory mode of convection, and heat transport in terms of the Nusselt number, which is governed by the non autonomous complex Ginzburg- Landau equation, is calculated. The effect of vertical through flow is found to stabilize the system irrespective of the direction of through flow in the case of permeable boundary conditions. The time relaxation has a destabilizing effect, while the time retardation parameter has a stabilizing effect on the system. The effects of amplitude and frequency of modulation on heat transport have been analyzed and depicted graphically. The study shows that the heat transport can be controlled effectively by a mechanism that is external to the system. Further, it is also found that heat transfer is more in oscillatory mode of convection rather than in stationary mode of convection.
Źródło:
International Journal of Applied Mechanics and Engineering; 2018, 23, 3; 635-653
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The sensitivity of vegetation in the lower Tigris basin landscapes to regional and global climate variability
Autorzy:
Alhumaima, Ali S.
Abdullaev, Sanjar M.
Powiązania:
https://bibliotekanauki.pl/articles/35516789.pdf
Data publikacji:
2021
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
climate variability
vegetation
global modulation
precipitation
temperature
Opis:
This study investigates the lower Tigris basin’s the normalized difference vegetation index (NDVI) sensitivity in 2000–2016 to regional climate variability reflected by the monthly precipitation and temperature time series of seven global datasets as well as to four global circulation indices. To examine the effect of climate variability on the different ecosystems, the study area has been classified into 10 smaller natural and anthropogenic landscapes based on landforms and land cover patterns. The preliminary analysis showed that the maximum biological productivity reflected by the NDVI of March and April has the highest correlation (0.5–0.8) to the same cumulative amounts of October–March period total precipitation and January–March period mean temperatures according to all datasets. In addition, this article showed there is a correlation between landscapes’ NDVI and global modulation represented by the September–February state of El Nińo-Southern Oscillation (ENSO) (0.55–0.70) and December state of the dipole mode index (DMI) (0.35–0.72). The significant differences in the original precipitation and temperature levels according to the different datasets have urged the use of normalized time series: z-score of temperatures and analogous six-months the standardized precipitation index (SPI). However, the multiple correlation analysis showed that using ERA-
Źródło:
Scientific Review Engineering and Environmental Sciences; 2021, 30, 1; 159-170
1732-9353
Pojawia się w:
Scientific Review Engineering and Environmental Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fiber Bragg grating-based high temperature sensor and its low cost interrogation system with enhanced resolution
Autorzy:
Mamidi, V R
Kamineni, S
Ravinuthala, L N S P
Madhuvarasu, S S
Thumu, V R
Pachava, V R
Putha, K
Powiązania:
https://bibliotekanauki.pl/articles/949414.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fiber Bragg grating (FBG)
long period grating
fiber optic temperature sensor
optical intensity modulation
Opis:
A fiber Brag grating-based high temperature sensor together with a low cost, high speed and compact size interrogation system using a long period grating was designed, developed and tested. The designed sensor measures the temperature from room temperature to 550 °C. The sensor head was configured by encapsulating an fiber Brag grating (type-I) of Bragg resonance wavelength at 1552.88 nm in a capillary tube made of copper. Long period grating with peak transmission loss at 1550 nm was employed to convert the wavelength information from fiber Brag grating into an intensity modulated signal. Temperature related optical intensity information was again converted into its equivalent electrical signal by using a photodiode. The achieved resolution of the sensor was found to be 0.5 °C.
Źródło:
Optica Applicata; 2014, 44, 2; 299-308
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discussion around IR material and structure issues to go toward high performance small pixel pitch IR HOT FPAs
Autorzy:
Gravrand, Olivier
Baier, Nicolas
Ferron, Alexandre
Rochette, Florent
Lobre, Clément
Bertoz, Jocelyn
Rubaldo, Laurent
Powiązania:
https://bibliotekanauki.pl/articles/2204207.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
mid-wave infrared
focal plane array
high operating temperature
small pitch
modulation transfer function
finite element method
Opis:
In the last decade, infrared imaging detectors trend has gone for smaller pixels and larger formats. Most of the time, this scaling is carried out at a given total sensitive area for a single focal plane array. As an example, QVGA 30 μm pitch and VGA 15 μm pitch exhibit exactly the same sensitive area. SXGA 10 μm pitch tends to be very similar, as well. This increase in format is beneficial to image resolution. However, this scaling to even smaller pixels raises questions because the pixel size becomes similar to the IR wavelength, but also to the typical transport dimensions in the absorbing material. Hence, maintaining resolution for such small pixel pitches requires a good control of the modulation transfer function and quantum efficiency of the array, while reducing the pixel size. This might not be obtained just by scaling the pixel dimensions. As an example, bulk planar structures suffer from excessive lateral diffusion length inducing pixel-to-pixel cross talk and thus degrading the modulation transfer function. Transport anisotropy in some type II superlattice structures might also be an issue for the diffusion modulation transfer function. On the other side, mesa structures might minimize cross talk by physically separating pixels, but also tend to degrade the quantum efficiency due to a non-negligible pixel fill factor shrinking down the pixel size. This paper discusses those issues, taking into account different material systems and structures, in the perspective of the expected future pixel pitch infrared focal plane arrays.
Źródło:
Opto-Electronics Review; 2023, 31, Special Issue; art. no. e144561
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

    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