نتایج جستجو برای: pumping

تعداد نتایج: 13661  

2011
Fathy M. Mustafa Ashraf A. Khalaf F. A. El-Geldawy

In the present paper, the problem of multi-pumping all Raman amplifier has been investigated to obtain a maximum flatness gain and increases the bandwidth of the cascaded Raman amplifiers over a wide range of optical signal wavelengths for long-haul ultra-wide wavelength division multiplexing (UW-WDM) transmission systems due to multi-pumping wavelengths and pumping power . Three cases are anal...

Journal: :Physical review letters 2004
Alexander O Govorov Jean J Heremans

We theoretically study hydrodynamic phenomena originating from electron-electron collisions in a two-dimensional Fermi system. We demonstrate that an electron beam sweeping past an aperture creates a pumping effect, attracting carriers from this aperture. This pumping effect originates from the specific electric potential distribution induced by the injected electrons. In the regions near the m...

2000
V. S. SINGH V. S. Singh

Abstract Well storage effect is generally considered while interpreting pumping test data from large diameter wells. However, in an aquifer of low permeability, the well storage is found to be significant during pumping tests conducted on bore wells. The interpretation of such data gives ambiguous results unless well storage effect is taken into account. A field example is presented to illustra...

ترکاشوند, مصطفی, فرهبد, امیر حسین, هاشمی زاده, سید علی,

The experimental study of passively Q-switched, LED-pumped Ce:Nd:YAG laser is reported. The active medium is a 3 mm diameter laser rod with 60 mm length; it is optically pumped with four segments of blue LEDs at 460 nm, with each segment consisting of 32 single LEDs. The 14 cm length optical resonator with 2 dielectric mirrors and the reflectivity of 99 and 93 percent at 1064 nm produced more t...

2012
Rajeev Ram Dennis Freeman

The work presented here is a study of thermally enhanced injection in light-emitting diodes (LEDs). This effect, which we refer to as "thermal pumping", results from Peltier energy exchange from the lattice to charge carriers when current is injected into an LED. For an applied voltage V such that qV < (hw), where q is the electron charge and (hw) is the average emitted photon energy, thermal p...

2010
Sukyoung Lee

A two-layer quasi-geostrophic model is used to study the effect of lower boundary Ekman pumping on the energetics of baroclinic waves. Although the direct impact of the Ekman pumping is to damp the total eddy energy, either the eddy available potential energy (EAPE) or the eddy kinetic energy (EKE), individually, can grow due to the Ekman pumping. Growth of EAPE is favored if the phase differen...

Journal: :Pediatrics 2001
D J Chapman S Young A M Ferris R Pérez-Escamilla

OBJECTIVE Women at risk for delayed onset of lactation are often advised to pump their breasts before lactogenesis stage II to hasten the timing of this process. The effectiveness of this clinical practice has not been previously evaluated. This study investigates the effects of breast pumping before the onset of lactation on early milk transfer and subsequent breastfeeding duration among women...

Journal: :Plant physiology 1992
K Shimazaki T Kinoshita M Nishimura

Signal transduction processes involved in blue light-dependent proton pumping were investigated using guard cell protoplasts from Vicia faba.N-[2-(Methylamino)ethyl]-5-isoquinolinesulfonamide, an inhibitor of cyclic AMP- and cyclic GMP-dependent protein kinases, had no effect. 1-(5-Isoquinolinesulfonyl)-2-methylpiperazine (H-7) and calphostin C, inhibitors of protein kinase C, produced slight i...

2001
Shu-Mei Wu Yio-Wha Shau Bor-Shyh Lin Fok-Ching Chong

We studied the effect of mechanical pumping on the response of peripheral arteries by focusing on the pulse wave velocity (PWV) in large arterial conduit and micro-vessels. The pressure waveforms were measured simultaneously at the brachial artery (BA), radial artery (RA) and finger. Impulse pumping was operated by alternatively adding 80mmHg pressure to the arm of normal subjects (N=10) in 3 s...

2011
L V Abdurakhimov M Yu Brazhnikov

We report recent results of the experimental study of capillary turbulence decay on the surface of quantum liquids: normal and superfluid He and liquid hydrogen. In our experiments the turbulent cascade of capillary waves was damped at high frequencies due to viscous dissipation. Turbulent spectrum in high-frequency dissipative region was described by exponential decay function which was in acc...

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