摘要:
The present invention relates to a novel process for removal of at least a portion of at least one metallic component of a metallic constituent from a multi-phase composite body. Particularly, by providing at least one of an infiltration enhancer or an infiltration enhancer precursor or an infiltrating atmosphere to be in communication with a permeable mass, which contacts at least a portion of a composite body, said metallic component of the composite body, when made molten, is caused to spontaneously infiltrate the permeable mass. Such spontaneous infiltration occurs without the requirement for the application of any pressure or vacuum. The metallic constituent is essentially leached or removed from the multi-phase body by spontaneous infiltration.
摘要:
An endodontic instrument of this disclosure has less torque strength but greater flexibility and enlarged chip space compared to the prior art. In embodiments. only two flutes are spiraled about the instrument's length L to form two non-landed cutting edges between D2 and D16, the cutting edges merging to form a land at about D1. The tip end is rounded. The helical angle α increases from the handle end toward the tip end, a number of spirals per unit length being at least two times greater toward the tip end than toward the handle end, a cross-section of the length L consisting of two convex portions intersecting at each cutting edge or a wave-shape having one concave portion and one convex portion intersecting at each cutting edge, the cross-section occupying less total area than would a same size endodontic instrument having a triangular cross-section and providing greater chip space.
摘要:
A method of producing an endodontic file that involves grinding in a plane substantially parallel to the longitudinal axis of a rotating dental instrument blank. By grinding the dental instrument blank in this manner, the torsional strength of the resulting endodontic file is not eroded during its production, thereby providing a file that is less susceptible to breakage during its use.
摘要:
A single use, reciprocal reverse rotation, endodontic file includes a plurality of spaced apart helical flutes with spiraled lands therebetween. The lands have an edge with a positive cutting angle when the file is rotated in one direction and a scraping angle when rotated in the opposite direction. The file provides for sequential rotation of a selected angle in a forward direction followed by rotation of a slightly less angle in a reverse direction. In one embodiment, the cross-sectional area of the flutes is concave polygonal-shaped at a proximal end of the file and square-shaped at the distal end. In another embodiment, the cross-sectional area of the flutes is convex arcuate-shaped, the lands lying normal to the central longitudinal axis of the file. The handle portion of the file may be configured for use in a rotary handpiece or for manual rotation.
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:
The present invention relates to a novel method of manufacturing a composite body, such as a ZrB.sub.2 --ZrC--Zr composite body, by utilizing a post-treatment technique which may improve the oxidation resistance of the composite body. Moreover, the invention relates to novel products made according to the process. The novel process modifies at least a portion of a composite body by exposing said body to a source of second metal.