Spurious signals such as the piezoelectric signal from a ferroelectric crystal or the ringing signal from the NMR probe head tuned for low gyromagnetic ratio nuclei are often observed in pulsed NMR. Both signals are cancelled using the Hahn echo sequence with appropriate phase cyclings. The present paper applies a composite-pulse sequence to cancel the ringing signal. The main advantage of this...

BACKGROUND The aim of the present study was to assess the clinical significance of spectral analysis of plethysmographic waveform in patients with coronary artery disease (CAD) and after coronary artery bypass graft (CABG) surgery. METHODS AND RESULTS The study group comprised 26 healthy subjects, 15 CAD patients, and 24 CAD patients after CABG. Finger plethysmographic waveforms from both rig...

in this paper, the electrochemical hydrogen storage in nanocomposite materials was studied. multi-walled carbon nanotubes (mwcnts) electrode was prepared by mixing with special composite. the optimum ratio of mwcnts was estimated 30-70% (w/w) in the composite material. mwcnts were synthesized by chemical vapor deposition (cvd). the nanocomposite was homogenized by microwave. cyclic voltammetry ...

In this paper, a novel method of cryogenically cooled (low-temperature nitrogen gas) wire tool is used during the oxygen-mist near-dry wire-cut electrical discharge machining (NDWEDM) process to cut Inconel 718 alloy material. The current, pulse-width, pulse-interval, and flow rate are controllable variables for response characteristics, such as material removal (MRR) wear ratio (WWR). Box-Behn...

Multiple platform coherent location systems operate by computing the time difference of arrival (TDOA) and frequency difference of arrival (FDOA) among signals received at geographically separated platforms. The bandwidth of the data link is the major bottleneck in the processing. Previously developed data compression methods [1, 2] can not satisfy the compression ratio and the accuracy require...

This study compared the effectiveness of the multifocal visual evoked cortical potentials (mfVEP) elicited by pattern pulse stimulation with that of pattern reversal in producing reliable responses (signal-to-noise ratio >1.359). Participants were 14 healthy subjects. Visual stimulation was obtained using a 60-sector dartboard display consisting of 6 concentric rings presented in either pulse o...

A backward dark-optical-comb-injection mode-locked semiconductor optical amplifier fiber laser (SOAFL) with a femtosecond pulse width and an ultrahigh supermode-noise suppressing ratio (SMSR) is primarily demonstrated. The mode-locked SOAFL pulse with a spectral linewidth of 0.45 nm is shortened from 15 to 8.6 ps under chirp compensation in a 420 m long dispersion-compensated fiber, correspondi...

Ultrashort echo time MRI requires specialized pulse sequences to overcome the short T(2) of the MR signal encountered in tissues such as ligaments, tendon, or cortical bone. Theoretical work is presented, supported by simulations and experimental data on optimizing the radiofrequency excitation to maximize signal-to-noise ratio and contrast-to-noise ratio. The theoretical calculations and simul...

Pulmonary hypertensive disease is assessed by quantification of pulmonary vascular resistance. Pulmonary total arterial compliance is also an indicator of pulmonary hypertensive disease. However, because of difficulties in measuring compliance, it is rarely used. We describe a method of measuring pulmonary arterial compliance utilizing magnetic resonance (MR) flow data and invasive pressure mea...

Brillouin optical time-domain reflectometry (BOTDR) is a branch of distributed fibre-optic sensors, and it can measure the strain temperature information, localised by return time probe pulse, along fibre based on spontaneous scattering process. Parameters BOTDR system, including spatial resolution, signal-to-noise ratio, measurement speed, sensing range, have mutually restrictive relationship....