Search results for "taper"
showing 10 items of 48 documents
Evaluación mediante micro CT de la eficacia del retratamiento de los conductos radiculares utilizando el microscopio clínico y los instrumentos ultra…
2018
El objetivo de este estudio fue comparar la eficacia y el tiempo de las técnicas, rotativas, manuales y recíprocas para eliminar el material de la obturación de los conductos radiculares, utilizando imágenes de microtomografía computarizada. Materiales y métodos: 99 diente humanos unirradiculares con conductos ovales, fueron instrumentados con el Sistema ProTaper Gold hasta la lima F2 según la técnica de crown-down y obturados con puntas de Gutacore Nº25 y sellador AH Plus. Las muestras se dividieron al azar en tres grupos de 33 dientes de cada uno. Después, los conductos radiculares fueron desobturados con limas de ProTaper R; Grupo 1, limas manuales de Hedstroem #25 y #30 y #35 con fresas…
Step vs. Two-Phase Gradual Volume Reduction Tapering Protocols in Strength Training: Effects on Neuromuscular Performance and Serum Hormone Concentra…
2020
ABSTRACT Seppanen, S and Hakkinen, K. Step vs. two-phase gradual volume reduction tapering protocols in strength training: Effects on neuromuscular performance and serum hormone concentrations. J Strength Cond Res XX(X): 000-000, 2020-This study assessed effects of 2 reduced volume tapering protocols on neuromuscular performance and serum hormone concentrations in 14 recreationally strength-trained men (21-30 years). After an 8-week strength training period subjects were divided to the step (54% volume reduction immediately) and 2-phase gradual (38% reduction for the first week and 70% for the second week) tapering groups for 2 weeks. One repetition maximum (1RM) squat, maximal isometric bi…
Ultrahigh-Q Tunable Whispering-Gallery-Mode Microresonator
2009
Typical microresonators exhibit a large frequency spacing between resonances and a limited tunability. This impedes their use in a large class of applications which require a resonance of the microcavity to coincide with a predetermined frequency. Here, we experimentally overcome this limitation with highly prolate-shaped whispering-gallery-mode "bottle microresonators" fabricated from standard optical glass fibers. Our resonators combine an ultra-high quality factor of 360 million, a small mode volume, and near lossless fibre coupling, characteristic of whispering-gallery-mode resonators, with a simple and customizable mode structure enabling full tunability.
Antenna Tapering Strategy for Near-Field Enhancement Optimization in Terahertz Gold Nanocavities
2019
Plasmonic nanoantennas (NAs) have received a growing attention in recent years due to their ability to confine light on sub-wavelength dimensions [1]. More recently, this property has been exploited in the terahertz (THz) frequency range (0.1–10 THz) for enhanced sensing and spectroscopy [2], as well as for more fundamental investigations [3]. These applications typically require high local electric fields that can be achieved by concentrating THz radiation into deeply sub-wavelength volumes located at the NAs extremities. However, the achievable near-field enhancement values are severely limited by the poor resonance quality factor of traditional rod-shaped THz NAs. Unlike what is commonly…
Tapering photonic crystal fibres for supercontinuum generation with nanosecond pulses at 532nm
2008
Experimental results on supercontinuum generation in photonic crystal fibre tapers using pump pulses of 7 ns duration at 532 nm are presented. Photonic crystal fibre tapers with the first wavelength of zero dispersion around 532 nm were fabricated. The generation of supercontinuum was investigated in normal and anomalous dispersion regimes. Supercontinuum spectra spanning more than 400 nm in the visible region are reported.
Anisotropy of the stiffness and strength of rigid low-density closed-cell polyisocyanurate foams
2016
The cells of polymer foams are usually extended in the foam rise direction, causing a geometrical anisotropy, the degree of which, characterized by the cell aspect ratio R, depends on foam density and production method. Such elongated cell shape translates into anisotropy of the mechanical properties of foams. Rigid low-density closed-cell polyisocyanurate foams of apparent density ranging from ca. 30 to 75 kg/m3, containing polyols derived from renewable resources, have been produced and tested for the stiffness and strength in the foam rise and transverse directions in order to experimentally characterize their mechanical anisotropy. Analytical relations for foams with rectangular paralle…
Apical root canal transportation of different pathfinding systems and their effects on shaping ability of ProTaper Next
2015
Background: This study aimed to compare glide path preparation of different pathfinding systems and their effects on the apical transportation of ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland) in mesial root canals of extracted human mandibular molars, using digital subtraction radiography. Materials and Methods: The mesial canals of 40 mandibular first molars (with curvature angles between 25° and 35°) were selected for this study. The specimens were divided randomly into 4 groups with 10 canals each. Glide paths were created in group 1 with #10, #15 and #20 K-type (Dentsply Maillefer, Ballaigues, Switzerland) stainless steel manual files; in group 2 with Path-File (Dentsply M…
Development of economic MeV-ion microbeam technology at Chiang Mai University
2017
Abstract Developing high technologies but in economic manners is necessary and also feasible for developing countries. At Chiang Mai University, Thailand, we have developed MeV-ion microbeam technology based on a 1.7-MV Tandetron tandem accelerator with our limited resources in a cost-effective manner. Instead of using expensive and technically complex electrostatic or magnetic quadrupole focusing lens systems, we have developed cheap MeV-ion microbeams using programmed L-shaped blade aperture and capillary techniques for MeV ion beam lithography or writing and mapping. The programmed L-shaped blade micro-aperture system consists of a pair of L-shaped movable aperture pieces which are contr…
Zobārstu pilnā vainaga preparātu konverģences pārbaude Latvijā, laboratorijas pētījums
2020
Ievads: Vienas vienības kroņa vai fiksētas daļējas protēzes saglabāšana un pretestība ir divi mehāniski faktori, kas ir saistīti ar veiktās atjaunošanas prognozi. Publicētajā literatūrā tiek atbalstīti īpaši zoba sagatavošanas parametri kroņa uzlikšanai. Preparācijas vertikālajām sienām jābūt ar konverģences leņķi no 10-14 grādiem, lai nodrošinātu kroņa saglabāšanu. Šo parametru neievērošana rada lielāku risku zaudēt kroņa saglabāšanu. Tomēr pētījumi liecina, ka šie kritēriji parasti netiek ievēroti. Nespēja ierobežot vertikālās sienas konverģenci (kopējo okluzālo konverģenci) izraisa protēzes struktūras zudumu, kariesu, palielina zobu struktūras zūdumu preparēšanas laikā un samazinā zoba p…
Acousto-optic interaction in biconical tapered fibers: shaping of the stopbands
2016
The effect of a gradual reduction of the fiber diameter on the acousto-optic (AO) interaction is reported. The experimental and theoretical study of the intermodal coupling induced by a flexural acoustic wave in a biconical tapered fiber shows that it is possible to shape the transmission spectrum, for example, substantially broadening the bandwidth of the resonant couplings. The geometry of the taper transitions can be regarded as an extra degree of freedom to design the AO devices. Optical bandwidths above 45 nm are reported in a tapered fiber with a gradual reduction of the fiber down to 70 μm diameter. The effect of including long taper transition is also reported in a double-tapered st…