摘要:
The present invention is a polyurethane dispersion that can be used to prepare polyurethane polymers which have moisture resistant properties. Moisture resistant polymers of the present invention are obtained by preparing the polymers from a polyurethane dispersion using a prepolymer formulation which includes an aliphatic mono, di or polyhydroxy compound which has an aliphatic side chain substituent which contains from 5 to 30 carbon atoms.
摘要:
Disclosed are stable aqueous polyurethane latexes prepared from prepolymer formulations including a polyisocyanate component and polyol component, wherein from 5 to 40 percent of the weight of the polyol component is ethylene oxide in the form of ethylene oxide applied as an end cap onto a propylene oxide or higher oxyalkylene polyoxyalkylene polyol, and no more than 45 percent of the weight of polyol component is ethylene oxide. These latexes are prepared without the use of organic solvents.
摘要:
An enclosure for selectively cooperating with embedded securing bars prevents unauthorized access to above ground portions or underground piping networks. The enclosure employs a pivot channel and a retainer channel separated by a distance substantially equal to the distance separating the securing bars. The pivot channel and the retainer channel are configured so as to require rotational and horizontal motion of the enclosure so as to operatively disposed the enclosure relative to the securing bars. The locking member of the enclosure is used to secure a securing bar within the retainer channel so as to prevent rotation of the enclosure relative to either securing bar.
摘要:
This is an electronic organ which economically simulates long duration aperiodic musical waveforms, such as the clash of cymbals. It employs the digital waveform generation technique, in which successive instructions are read out of a memory to determine the amplitude of the waveform at successive sample points. To save memory capacity, the memory addresses are rescanned; and to avoid audible discontinuities the scan direction recirculates numerically back and forth across the address field. Despite the bidirectionality of the scan, monotonic decreases in amplitude and in higher harmonic content are achieved. The monotonic decrease in amplitude is accomplished by impressing an exponentially declining envelope upon the digitally generated amplitudes. The monotonic decrease in higher harmonic content is accomplished by preventing the rescan from returning to a memory region of greater harmonic content after it has once entered a region of lesser harmonic content.
摘要:
A multimode fiber optic coupler includes a first multimode optical fiber having a core and cladding surrounding the core and having a first longitudinal segment in which the cladding has been substantially removed exposing the core and in which a portion of the exposed core forms a first biconical taper segment; a second multimode optical fiber having a core and a cladding surrounding the core and having a second longitudinal segment in which the cladding has been substantially removed exposing the core and in which a portion of the exposed core forms a second biconical taper segment; and a coupling region formed by portions of the first and second biconical taper segments being fused together in parallel juxtaposition with one another.
摘要:
This invention relates to tone generating systems for polyphonic electronic musical instruments. The system includes a plurality of programmable tone generators each of which is assigned to a different note to be sounded. For a preferred embodiment, one of the programmable tone generators is designated as a solo high tone generator, and is always utilized to produce the highest note to be sounded. Another generator may be designated as the solo low generator, and will always be utilized to generate the lowest note to be sounded. Additional solo note generators may be provided if desired. Tone generators are interconnected in a priority scheme with one generator at a time being designated as the next generator to be assigned a note to be sounded, and the designation being advanced in a predetermined manner as notes are assigned successively to the generators. One or more keyers are associated with each programmable tone generator, and receive a keyer enable signal from the tone generator when a note to be sounded is stored therein. Each generator also generates one or more pulse code outputs to its corresponding keyers, programming them to adapt to the selection of musical notes over a multi-octave range. Phase cancellation between two notes which are octavely related is avoided by duplicate generation of one of the notes in both master and slave tone generators, the code for any note being stored in both the master and slave generators whenever it is determined that the code for an octavely related note is already stored in another master generator. Various special effects are achieved by selectively dropping pulses from the clock signal applied to the programmable divider of the generator.
摘要:
Polyurethane foams having improved retention of insulative properties can be prepared using one or more of two novel polyols. One of the polyols is a polyether prepared by reacting a monoepoxide with a compound having the general formula: ##STR1## wherein X is H, Li, Na, K; A is N, S or O; L is a covalent bond or a connecting group having from 1 to 10 carbons; M is any group capable of reacting with an ethylene oxide molecule in the presence of a basic catalyst; and J is an integer from 2 to 8. The other polyol is prepared by (1) admixing ethylene carbonate and one or more hydroxyl functional compounds under reaction conditions sufficient to react the ethylene carbonate and the hydroxyl functional compounds to produce a polyol precursor, and (2) admixing the polyol precursor with diethylene glycol and an anhydride, a dicarboxylic acid, a tricarboxylic acid or mixtures thereof, optionally in the presence of a catalyst.
摘要:
Poly(1-oxy-3-lactam vinylenes) of the formula ##STR1## wherein n is 1, 2, or 3 are disclosed formed by the polymerization of 1-(2-chloroacetyl)lactams having 5, 6, or 7 carbon atoms in the lactam ring. The polymers are useful reactants in polyester and polyurethane formation.
摘要:
A method of bonding glass-based optical elements comprising the steps of positioning a first glass-based optical element relative to a second glass-based optical element, applying a glass-based bonding compound about the first and second optical elements, and applying sufficient localized heat to the glass-based bonding compound to cause the glass-based bonding compound to soften and fuse with the optical elements.
摘要:
A broadband optical fiber coupler comprising at least three continuous optical fibers fused at a region of coupling, at least one of the continuous optical fibers being dissimilar to others of the continuous optical fibers in the region of coupling, the region of coupling being of a length and the dissimilarity being of a degree to provide broadband response over a predetermined range of wavelengths. A related method for making a broadband optical fiber coupler is also disclosed.