摘要:
A functional TFE copolymer fine powder is described, wherein the TFE copolymer is a polymer of TFE and at least one functional comonomer, and wherein the TFE copolymer has functional groups that are pendant to the polymer chain. The functional TFE copolymer fine powder resin is paste extrudable and expandable. Methods for making the functional TFE copolymer are also described. The expanded functional TFE copolymer material may be post-reacted after expansion.
摘要:
The invention is a method of reducing catalyst dissolution in the cathode of a membrane electrode assembly fuel cell, the method comprising the steps of: (a) preparing a membrane electrode assembly comprising an anode, a cathode and a polymer electrolyte membrane interposed between the anode and the cathode; (b) assembling a fuel cell using the membrane electrode assembly; (c) applying a fluid comprising an oxidant to the cathode of the membrane electrode assembly; (d) applying a fluid comprising a fuel to the anode of the membrane electrode assembly; and (e) supplying a sufficient quantity of reducing agent to the cathode to maintain the average open-circuit voltage of the cathode at less than about 0.98 V.
摘要:
A rotatable endodontic file for cleaning/shaping a tooth root canal, comprising an elongated shaft having a proximal end portion, a distal end and a tapered working portion having a rotational axis, the working portion extending from the proximal portion to the distal end, the external surface of the shaft working portion having a plurality of at least two spiraled, spaced apart continuous helical flutes, the flutes having therebetween an equal number of spiraled, spaced apart flanges, each flange having in a plane perpendicular the rotational axis an outer end surface forming a continuous spiraled scraping/cutting edge extending the length of the shaft working portion, the flutes having helical angles relative to the rotational axis of between 10° and 30° and wherein the helical angles vary at selected longitudinal locations.
摘要:
An improved fishing lure employing a wire frame (10) having first (14) and second arms (16) that extend in divergent directions with respect to each other. A fish attracting element (18) and a hook (20) are secured to one arm (14), and a spinner (32) is attached to the other arm (16). The wire frame is formed of a nickel titanium alloy which provides flexibility and shape memory that are substantially greater than that provided by conventional stainless steel wire whereby when the lure is pulled through water, it has improved fish attracting action. Wire and cable fishing leaders formed of a nickel titanium alloy are disclosed which exhibit appreciable elongation and resistance to kinking and spiralling.
摘要:
The invention provides a novel formed product and method of producing a hard, dry, e.g., agglomerated or formed, product useful as a construction material comprising: a) papermill sludge made up of paper fiber, clay and calcium carbonate, b) ash such as coal ash (typically stack scrubber solids obtained from the burning of coal), and c) water. The amount of water present is selected to render the product plastic so that it can be molded to the desired shape. An oxidizer is provided in a sufficient amount to oxidize unstable compounds and to convert potassium, calcium or magnesium bisulfite to the sulfate form. Following the addition of the oxidizer, the admixture is exposed to electromagnetic energy, preferably ultraviolet light, to help drive the oxidation reaction to completion. In an optional form of the invention, a minor amount of a cation exchange resin is added to the mixture to sequester heavy metals. The admixture is formed or molded into pieces or bodies of the desired shape, such as blocks, slabs or pellets or agglomerates. The resulting pieces dry and harden at room temperature. They are unfused, contain retained wood fiber, are substantially dust free, hard, dry, and environmentally stable. They give off little or no objectionable odor. They are clean and when placed in water, will not release significant quantities of heavy metals. The formed bodies have enough strength to be used as an aggregate in a concrete product that exhibits good compression strength.
摘要:
Method of installing a post in a tooth having a metal obturator therein including the steps of drilling a borehole in the tooth with a tubular burr having a tubular opening therein of internal diameter at least slightly greater than the diameter of the obturator to thereby provide a borehole of selected internal diameter having the metal obturator remaining essentially therein, the obturator serving to assist in the guiding of the burr and inserting a tubular post into the borehole, the post receiving the metal obturator therein, the post extending partially above the top of the tooth to provide means for attachment of a crown or the like.
摘要:
An indexable face-milling insert having eight compound cutting edges of the same hand, each having an included angle of 90.degree. over its entire length which comprises two straight segments at right angles to each other and an intermediate bevel cutting portion.
摘要:
An improved rotary endodontic file includes a multi-planar pre-curved apical portion having a first and a second curvature. The pre-curved apical portion begins at about one-third to one-quarter of the working length as measured from the tip end of the endodontic instrument. The first and second curvature permit the file to continually search and engage the walls of a tooth root canal in a forced inside-forced outside manner. As the file works its way down, it breaks free of any ledges encountered, probes lateral- and delta-type openings, and does not allow the file to stray from the curvature of the canal.
摘要:
A fatigue-resistant Nitinol instrument has a working portion in the deformed monoclinic martensitic state and an austenite finish temperature in the range of 40° to 60° C. Because the operating environment of the instrument is about 37° C., the working portion remains in the monoclinic martensitic state during its use. The relatively high austenite finish temperature and fatigue resistance is achieved by subjecting the nickel-titanium alloy to a final thermal heat treat in a temperature range of about 410° to 440° C. while the nickel-titanium alloy is under constant strain of about 3 to 15 kg. Further, the high austenite finish temperature is achieved without subjecting the alloy to thermal cycling to produce shape memory. Additionally, there are no intermediate processing steps occurring between obtaining a finished diameter of the wire or blank through cold working and the final thermal heat treat under constant strain.
摘要:
Methods for disinfecting and removing smear layer from prepared tooth surfaces are provided. The methods involve irrigating the tooth surface with a disinfectant solution containing doxycycline or tetracycline, a surfactant such as polysorbate, and organic acid such as citric acid. The methods can be used in various dental treatments including, for example, endodontic and periodontic procedures as well as tooth restoration and reconstruction.