摘要:
A steering apparatus (10) includes first and second assemblies (16 and 26). The second assembly (26) includes a steering gear (28) and first and second drive units (30 and 32), each for actuating the steering gear (28). The second assembly (26) has first and second modes of operation. The first and second drive units (30 and 32) operate simultaneously for actuating the steering gear (28) when the second assembly (26) is operating in the first mode of operation. Only one of the first and second drive units (30 and 32) is operated when the second assembly (26) is operating in the second mode of operation.
摘要:
An electrically releasable form of hook and loop fastener (10) allows one half of the fastener to release from the other half without applying direct physical force to either half. The hook elements (21) of the fastener are formed of a shape-memory alloy material (27) such as commercially available Ninitol. Release of the hook half (14) of the fastener from the loop half (12) is accomplished by passing an electrical current through the shape-memory alloy material to straighten the hooks (21) so that they release their engagement with the loops (18). The flow of electricity through the hook half energizes the Ninitol material (27) to change its shape, either expanding or contracting in length; the change in shape is made to act against another length of material (28) that remains fixed in length or changes shape in an opposite direction so as to cause the hook shape to straighten toward a rod shape. Upon termination of the flow of electrical energy, the hooks return (21) to their hook shape, ready for re-engagement with the loops (18) upon conventional mating of the two halves of the fastener. Release and re-engagement can be repeated, substantially indefinitely.
摘要:
Syndiotactic polypropylene blends having a unique set of mechanical properties may be prepared by blending syndiotactic polypropylene with an ultra low density polyethylene and, optionally, an isotactic polypropylene random copolymer. The syndiotactic polypropylene blends of the present invention have been found to have improved impact strength, reduced haze, increased light transmittance, and reduced flexural modulus. It has been determined that the addition of about 10 to about 50 wt % of an ultra low density polyethylene plastomer to a syndiotactic polypropylene can greatly enhance mechanical toughness, particularly at low temperatures, while maintaining good optical clarity. These results are made possible by using a sPP material with good optical clarity and dispersing the ULDPE plastomer uniformly throughout the sPP matrix to act as a sort of impact modifier. Moreover, the addition of about 10 to about 50 wt % of an iPP random copolymer to the sPP matrix phase provides comparable or improved mechanical properties while also resulting in a significant reduction in injection molding cycle times. The syndiotactic polypropylene blends according to the present invention may be further processed according to accepted practices to make cast films, blown films, co-extruded films, laminated sheets, injection molded parts, blow molded containers, and other articles using basic plastic fabrication techniques as known in the art.
摘要:
An antenna arrangement comprises a ground plane (14) and a planar antenna element (30) mounted spaced from and parallel to the ground plane. An open-ended slot (16) is provided in the ground plane (14), the slot being coextensive with an edge portion of the ground plane and having a first end (18) opening into the edge portion of the ground plane and a second closed end (20). An antenna feed (22) is coupled to the slot at a location intermediate the first and second ends. The planar antenna element is connected by an electrically conductive wall (28) to the edge portion of the ground plane, the wall (28) being coextensive with the slot (16). The combination of the slot shape, slot location and the wall serves to increase the bandwidth of the antenna arrangement.
摘要:
An endovascular prosthesis includes a tubular body and a flexible springy mobile external coupling. The tubular body includes a graft material and stents coupled thereto with a forms a lumen therethrough. The mobile external coupling extends outwardly from the tubular body. The mobile external coupling includes a graft material and is generally frustoconically shaped. The mobile external coupling includes a base coupled to the tubular body, a top spaced from the tubular body, and a coupling lumen disposed between the base and the top, wherein the coupling lumen is in flow communication with the body lumen. A helically shaped stent may be coupled to the coupling graft material to make it flexible and springy.
摘要:
A wireless terminal is described, which is formed from a module (20) comprising a substrate, RF components (32, 33), an antenna (25), notably of the PIFA type, and a linkage part (30) for linking the antenna to the substrate. The RF components are placed in the vicinity of the linkage part or even on the linkage part without degrading the operation of the antenna. By placing the RF components on this link, an area is made available for circuitry on the substrate.
摘要:
A communications device, such as a cellular telephone (10), comprises a rf circuit and a PIFA antenna (16) having feed and shorting terminations. An electrically conductive, self supporting member (18) is provided to effect a connection between contact points of the rf circuit and the antenna The member (18) has at least one feed pillar (24,26) and a shorting pillar (22) which are substantially permanently connected to respective contact points of the rf circuit, and an antenna interface (28) which forms a pressure connection with the terminations of the antenna.
摘要:
An antenna arrangement comprises a patch conductor (102) supported substantially parallel to a ground plane (104). The patch conductor includes first (106) and second (108) connection points, and further incorporates a slot (202) between the first and second points. The antenna can be operated in a first mode when the second connection point is connected to ground and in a second mode when the second connection point is open circuit. By connection of a variable impedance (514), for example a variable inductor, between the second connection point and the ground plane, operation of the arrangement at frequencies between the operating frequencies of the first and second modes is enabled.
摘要:
A wireless terminal for use in the transmitting and receiving frequency bands of a frequency duplex system comprises transmitting and receiving stages (Tx, Rx) and signal propagating means (22, 24, 26) coupled to the transmitting and receiving stages. The signal propagating means comprises a narrow band antenna structure (24), such as a Planar Inverted-F Antenna (PIFA), having sufficient bandwidth to cover the larger one of the transmitting and receiving frequency bands and a BAW receiving filter (26) and a BAW transmitting filter (22) coupled by respective feeds to the antenna structure (24). The filters (22, 26) enable the antenna structure to have a small volume and be reusable at different FDD frequencies.
摘要:
A wireless terminal comprises a radio frequency stage (20) coupled to a signal propagator (22). The signal propagator comprises a folded dipole formed by an aperture (40), for example a T-shaped aperture, in at least the ground plane of a printed circuit board (PCB). The width (c) of the aperture is small relative to the area of the ground plane and is substantially smaller than its length (a). A feed (42) couples an output of the radio frequency stage (20) to the aperture (40).