Search results for "rate dependent"
showing 4 items of 4 documents
Is atrial sensing of ventricular far-field signals important in single-lead VDD pacing?
1998
UNLABELLED In single-lead VDD pacing the atrial sensitivity frequently is programmed to sensitive values. Atrial sensing of ventricular far-field signals should be reduced by differential atrial sensing. The aim of the study was to evaluate the effectiveness of this approach. METHODS The study included 10 patients with a single-lead VDD pacemaker (Thera 8948, Lead 5032). The atrial sensitivity was set to its most sensitive value of 0.18 mV and the telemetered intraatrial EGM was continuously recorded. After atrial tracked ventricular pacing, VVI pacing was performed with pacing rates from 100 to 160 beats/min in steps of 10 beats/min and up to 165 beats/min. The peak-to-peak amplitudes of P…
Relaxation times at the rate-dependent glass transition
1997
The structural relaxation time near the cooling rate dependent glass transition is determined self-consistently within the Moynihan-Narayanaswami formalism. In order to illustrate the method we analyze scanning calorimetry data from amorphous calcium-rubidium nitrate. A characteristic time scale of about 250 s is obtained at the conventionally defined glass transition. The occurrence of decoupled, faster relaxation modes is briefly discussed.
Nonstationary flow surface theory for modeling the viscoplastic behaviors of soils
2016
Abstract This paper presents a three-dimensional elastic viscoplastic model that can describe the time-dependent behaviors of soft clays. The constitutive model is formulated based on the nonstationary flow surface theory and incorporates new developments, including (i) an improved definition of the nonstationary flow surface that is capable of capturing the stress–strain behaviors under different loading paths, (ii) a unique stress–strain—viscoplastic-strain-rate equation that is able to explicitly describe the nonstationary flow surface, and (iii) a final stable state concept that identifies the final equilibrium state at the end of creep and stress relaxation, which is also used to simpl…
Separation of amino acid enantiomers using supported liquid membrane extraction with chiral phosphates and phosphonates
1999
A series of dialkyl and monoalkyl phosphates, phosphites and phosphinates based on (−)-menthol and (−)-nopol were synthesized and used as carriers for transport of aromatic amino acids through supported liquid membranes. Although all the compounds were found to be effective carriers (with transport rate dependent on their structure) the enantioselectivity of the process obtained was low or moderate. Aromatic amino acids were enantioselectively transported through supported liquid membranes containing chiral phosphates, phosphites and phosphinates as carriers. Download full-size image