The current study examined the self-excited thermoacoustic instability of hydrogen/methane premixed flames using a variable-length combustor (300–1100 mm). global dynamic pressure, heat release rate oscillation, together with flame dynamics were studied. Results showed that both hydrogen concentration and chamber length critical in determining acoustic oscillation mode trend. Low-frequency prim...

In this paper an analytical model of the oscillation frequency of a differential CML ring oscillator is proposed. The model helps to choose the bias current value to optimize speed, and it is useful to estimate the oscillation frequency changes associated with the bias current change and to process tolerances. Moreover, it allows to relate the propagation delay of a gate evaluated in a ring osc...

Multiphase clocks are very useful for realizing high-speed data processing systems with low-speed circuit elements. Triggered in sequence by equally-spaced N-phase clock signals, multiphase systems can achieve N-times higher operating frequencies than single-phase clocked systems. For this reason, multiphase clocks are often used for such applications as high-speed analog-digital converters (AD...

Among fluctuations of instantaneous heart rate (IHR) in newly hatched chicks, heart rate (HR) oscillation with a mean frequency of 0.7 Hz has been designated as Type II HR variability characterized by low frequency (LF) oscillation [Comp. Biochem. Physiol. Part A 124 (1999) 461]. In response to exposure to lowered ambient temperature (Ta), chick hatchlings raised their HR baseline accompanied w...

extremely low frequency (elf) electromagnetic field (elf-emfs) are widely employed in electrical appliances and different equipment such as television sets, elf-emfs can  affect biological systems by increasing production  ros. the altered balance between ros generation and elimination plays a critical role in a variety of pathologic conditions. ros levels have been observed in several hematopo...

This paper presents a current-mode four-phase third-order quadrature oscillator (QO) using current differencing transconductance amplifiers (CDTA). The proposed thirdorder QO consists of three CDTAs and three grounded capacitors, and it could generate four quadrature current outputs. The oscillation condition and oscillation frequency could be electronically and independently adjusted. Moreover...

We describe application of spectral analysis of laser Doppler flowmetry (LDF) signals to investigation of cerebrovascular haemodynamics in patients with post-acute ischemic stroke (AIS) and cerebrovascular insufficiency. LDF was performed from 3 to 7 days after the onset of AIS on forehead in the right and left supraorbital regions in patients. Analysis of LDF signals showed that perfusion in t...

Sharp wave bursts, induced by a cooperative discharge of CA3 pyramidal cells, are the most synchronous physiological pattern in the hippocampus. In conjunction with sharp wave bursts, CA1 pyramidal cells display a high-frequency (200 Hz) network oscillation (ripple). In the present study extracellular field and unit activity was recorded simultaneously from 16 closely spaces sites in the awake ...