摘要:
An insoluble photosensitive polyimide having the formula ##STR1## can be exposed by a pattern of light to render the exposed areas soluble. The exposed areas can then be dissolved using a solvent to leave the pattern which can be used directly as an insulator layer in a semiconductor device. A process for preparing the photosensitive soluble polyimide utilizes maleic anhydride which is irradiated by ultraviolet light to form a cyclobutane unit which is reacted with oxydianiline to form polymic acid. The polymic acid is cured using heat into the photosensitive soluble polyimide.
摘要:
An insoluble electron beam positive polyimide having the formula ##STR1## can be exposed by an electron beam to render the exposed areas soluble. The exposed areas can then be dissolved using a solvent to leave the pattern which can be used directly as an insulator layer in a semiconductor device.
摘要:
Methods and apparatus are described for a navigation system. A process includes providing a plurality of transmitters distributed throughout a desired coverage area; locking the plurality of transmitters to a common timing reference; transmitting a signal from each of the plurality of transmitters. An apparatus includes a plurality of transmitters distributed throughout a desired coverage area; wherein each of the plurality of transmitters comprises a packet generator; and wherein the plurality of transmitters are locked to a common timing reference.
摘要:
Methods and apparatus are described for a navigation system. A process includes providing a plurality of transmitters distributed throughout a desired coverage area; locking the plurality of transmitters to a common timing reference; transmitting a signal from each of the plurality of transmitters. An apparatus includes a plurality of transmitters distributed throughout a desired coverage area; wherein each of the plurality of transmitters comprises a packet generator; and wherein the plurality of transmitters are locked to a common timing reference.
摘要:
A method for purifying oligonucleotides by displacement chromatography on anion-exchange media, using high affinity, low molecular weight (less than about 10000 Da) displacers, is disclosed. Several examples of high affinity, low molecular weight anionic displacers are provided, including polycyclic aromatic compounds having sulfonic acid moieties attached thereon. The efficacy of the technique for high resolution separation of oligonucleotides is demonstrated for an industrial mixture.
摘要:
A method for the purification of proteins by displacement chromatography on ion exchange media using low molecular weight displacers is disclosed. Several classes of low molecular weight, charged species are exemplified, including aminoacids, peptides, antibiotics and dendrimeric polymers. Novel compounds useful as displacers are dendrimers of formula ##STR1## wherein R.sup.1 is lower alkyl, n is 2 to 6, and X is a common counter anion and similar dendritic polymers based thereon.
摘要:
A balanced, closed cycle silicon refinery system has been developed for producing electronic grade silicon from industrial grade silicon. Impurities comprising approximately 1% of the industrial grade silicon are removed in the refinery system to produce the purified silicon, while only a relatively small percentage of make-up chemicals are added to the system. In the refinery, hydrogen chloride is reacted with the impure silicon in a halide reactor to provide trichlorosilane and silicon tetrachloride and hydrogen. The trichlorosilane and/or silicon tetrachloride are passed through purification means, and then reacted with the hydrogen from the halide reactor in a fluidized bed reactor to produce the purified silicon and an effluent comprised of unreacted trichlorosilane, silicon tetrachloride, hydrogen, and the by-product hydrogen chloride. These materials are passed through a separator and the trichlorosilane and silicon tetrachloride and hydrogen are returned to the silicon reactor while the hydrogen chloride is returned to the halide reactor to be reacted with additional industrial grade silicon.
摘要:
Methods and apparatus are described for a navigation system. A method includes providing a global positioning system fix having a plurality of tracking parameters; providing a theater positioning system fix; monitoring the plurality of tracking parameters for predetermined conditions; and, when the predetermined conditions are met, sending a notifying signal and switching to the theater positioning system fix as a primary fix. An apparatus includes a system controller; a global positioning system receiver coupled to the system controller; a radio frequency locating receiver coupled to the system controller; and an operator interface coupled to the system controller.
摘要:
Methods and apparatus are described for a navigation system. A process includes providing a plurality of transmitters distributed throughout a desired coverage area; locking the plurality of transmitters to a common timing reference; transmitting a signal from each of the plurality of transmitters. An apparatus includes a plurality of transmitters distributed throughout a desired coverage area; wherein each of the plurality of transmitters comprises a packet generator; and wherein the plurality of transmitters are locked to a common timing reference.
摘要:
Methods and systems for treating a gas stream comprising NOx are disclosed. In one embodiment of the method, the gas stream comprising NOx is reacted with ozone to form oxidation products including nitrogen sesquioxide and nitrogen pentoxide. At least a portion of the nitrogen sesquioxide and nitrogen pentoxide is reacted with water to form nitric acid, and a solubilized form of the nitric acid is collected and may be reused or otherwise utilized. Systems for conducting the method also are disclosed.