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Natural gutta-percha is well known for its mechanical properties which derive from its particular stereochemical 1-4 trans structure. The gutta-percha contained in the various commercially available points is made of natural gutta-percha which has undergone a heating process to allow inclusion of the other elements found in its composition, especially a(More)
Thermocycling is often used in the in vitro evaluation of marginal leakage of dental restorations. The in vivo temperatures occurring during meals were recorded at different surfaces of restored teeth, to compare the variations in temperature with laboratory thermocycling. Temperatures were recorded with thermocouples at three different sites: (1) on the(More)
The purpose of this investigation was to determine the chemical composition, confirmed on X-ray diffraction analysis, of some commercially available dental gutta-percha cones. In addition, their plasticity in response to temperature variations was studied by differential scanning calorimetry. Great chemical heterogeneity was found among gutta-percha cones(More)
Samples of three common commercial gutta-percha endodontic filling points (Hygienic, Mynol, and Maillefer Pink) and a sample of natural gutta-percha were submitted to thermomechanical analysis under pressures ranging from 0.01 to 0.2 N. Samples of Mynol and Maillefer filling points were thermally treated and then submitted to thermomechanical analysis in(More)
We consider the problem of code acquisition at low signal to interference and noise ratio (SINR) in packet-based spread spectrum communications, where a centralized "pilot" synchronization signal and high-precision oscillators are not available. Such problems arise in the context of ad-hoc networks, for example, which require fast code acquisition times and(More)
— A low signal to interference and noise ratio (SINR) wireless environment makes successful reception and accurate detection of packets a challenging task. We can combat a low SINR by using direct-sequence spread spectrum modulation with a sufficiently high processing gain, as well as by employing block codes for FEC on each packet. In this paper, we(More)
Ability to receive signals at low signal to interference and noise ratio (SINR) improves the spatial range and reliability of wireless networks. However, it is difficult to design a communication system that operates correctly in this type of environment. Our system uses a high spreading gain in the direct-sequence spread-spectrum (DSSS) modulation to(More)
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