摘要:
A light weight antenna system and corresponding lightweight transmission lines are disclosed that are characterized as having an extremely light weight relative to prior such systems and lines. An inflatable body having an inner surface connected to an outer surface with a plurality of support structures, such as connecting tubes. Antenna elements are disposed on the outer surface of the inflatable body to form, for example, a phased array antenna. Coaxial transmission lines are used to transmit signals to and from an antenna element and are, in one embodiment, created by disposing an inner conductor within the aforementioned connecting tubes. Such a transmission line may be utilized in a number of applications, such as to connect a base station to an antenna system of a wireless communications network. In another embodiment, quasi coaxial transmission lines are formed by disposing flexible membrane shields around a transmission elements.
摘要:
A cell suitable for use with an atomic clock and a method for making the same, the cell including: a silicon wafer having a recess formed therein; at least one amorphous silicate member having an ion mobility and temperature expansion coefficient approximately that of silicon sealing the recess; and, an alkali metal containing component and buffer gas contained in the recess. The method includes: providing a silicon wafer; forming a cavity through the silicon wafer; introducing an alkali metal containing component and buffer gas into the cavity; and, anodically bonding at least one amorphous silicate member having an ion mobility and temperature expansion coefficient approximately that of silicon to the wafer to close the cavity.
摘要:
An apparatus, system, and method are disclosed for the direct retrieval of hierarchical data from an SAP system. The apparatus includes an input module, a table hierarchy module, a query builder module, a query execution module, and a response builder module. The input module receives a table business object comprising a query criteria. The table hierarchy module determines a table hierarchy associated with the table business object. The query builder module builds a native SAP query based on the table hierarchy and the query criteria. The query execution module executes the native SAP query directly on an SAP database. The response builder module returns results of the native SAP query.
摘要:
Wet laid, nonwoven, fibrous mats suitable for making MERV 6 or higher filters, and methods of making the nonwoven mats are disclosed. The mats include a blend comprising a major portion of glass fibers and a minor portion of man-made polymer fibers, such as polyester fibers, the fibers being bound together with a cured binder having a Tg in the range of about minus 30 to about 50 degrees C. The mats are pleated prior to assembling the filter in conventional manner. The only fibrous mat in the filters is wet laid fibrous nonwoven mat and the pleated filter media needs no other means of support in the filter frame.
摘要:
A system and method are provided for coding a frame in a packet communications system using a G.709 Digital Wrapper Frame format. The method comprises: accepting digital information; outer encoding the digital information with a Reed Solomon (RS) encoding scheme; interleaving the outer encoded information; inner encoding the interleaved information using a BCH encoding scheme; and, forming a G.709 Digital Wrapper frame including payload and parity bytes. More specifically, a standard DW superframe is formed with 122,368 bits of payload and 8192 bits of parity. The outer encoding process uses an RS(1023,1007) parent code. In one aspect, 15 groups of RS(781,765) and 1 group of RS(778,762) codewords are formed per superframe. The inner encoding process uses a BCH(2047,1959) parent code. In one aspect, 64 groups of BCH(2040,1952) codewords are formed per superframe.
摘要:
A chip scale atomic clock is disclosed that provides a low power atomic time/frequency reference that employs direct RF-interrogation on an end-state transition. The atomic time/frequency reference includes an alkali vapor cell containing alkali atoms, preferably cesium atoms, flex circuits for physically supporting, heating, and thermally isolating the alkali vapor cell, a laser source for pumping alkali atoms within the alkali vapor cell into an end resonance state by applying an optical signal along a first axis, a photodetector for detecting a second optical signal emanating from the alkali vapor cell along the first axis, a pair of RF excitation coils for applying an RF-interrogation signal to the alkali atoms along a second axis perpendicular to the first axis, a pair of bias coils for applying a uniform DC magnetic field along the first axis, and a pair of Zeeman coils for applying a Zeeman interrogation signal to the alkali atoms and oriented and configured to apply a time-varying magnetic field along the second axis through the alkali vapor cell. Another flex circuit is used for physically supporting the laser source, for heating the laser source, and for providing thermal isolation of the laser source. The laser source can be a vertical cavity surface emitting laser (VSCEL). The bias coils can be Helmholtz coils.
摘要:
A water-cooled stator bar clip for electrical generators and a method for applying a corrosion-resistant protective coating, preferably Sc, Ti, Cr, Zr, Nb, Mo, Hf, Ta, W, Ni, and Al, and their alloys or oxides to existing stator bar end fittings in order to significantly reduce the possibility of leaks through the brazed connections of the copper stator bar end connections. The coatings can be applied locally using various known physical vapor deposition (“PVD”), chemical vapor deposition (“CVD”) or other direct coating techniques known in the art. For example, the coatings can be applied using ion plasma deposition, sputtering or wire arc techniques (all PVD processes) or by using electroplating, high velocity oxygen free (“HVOF”) deposition, DC arc or electroless plating. Preferably, the coatings are applied either to new stator bar clips or to existing clips in the field.
摘要:
A low-jitter optical pulse source including: a monolithic waveguide including a first section substantially perpendicular to a first facet and a second section being curved and substantially non-perpendicular to a second facet; and, an optical circulator coupled to the monolithic waveguide and forming a sigma cavity in combination with the monolithic waveguide, wherein the first facet forms a sole reflector for the sigma cavity.
摘要:
A light weight antenna system and corresponding lightweight transmission lines are disclosed that are characterized as having an extremely light weight relative to prior such systems and lines. An inflatable body having an inner surface connected to an outer surface with a plurality of support structures, such as connecting tubes. Antenna elements are disposed on the outer surface of the inflatable body to form, for example, a phased array antenna. Coaxial transmission lines are used to transmit signals to and from an antenna element and are, in one embodiment, created by disposing an inner conductor within the aforementioned connecting tubes. Such a transmission line may be utilized in a number of applications, such as to connect a base station to an antenna system of a wireless communications network. In another embodiment, quasi coaxial transmission lines are formed by disposing flexible membrane shields around a transmission elements.