A system and method for providing a traffic control scheme for QoS provision and congestion control across multiple interfaces of wireless nodes (102, 106 and 107), such as wireless access points (107 and 106), communicating in a wireless multihopping communication network (100). The nodes (102, 106 and 107) can include multiple transceivers. The system and method detects bottleneck interfaces in these nodes (102,106, 107) to control the traffic along the path of the corresponding traffic flow. Different measurements and cross-layer feedback are used to differentiate the cause of the congestion, such as wireless link quality degradation due to fading or degradation due to congestion in a shared medium. The nodes (102, 106, 107) inform each other on the status of their congestion level. High and low level signaling and interruption mechanisms are used to control the interfaces of the congested node (102, 106 or 107) to adjust traffic flow and alleviate the congestion.

In recent years, a type of mobile communications network known as an "ad-hoc" network has been developed for use by the military. In this type of network, each mobile node is capable of operating as a base station or router for other mobile nodes, thereby eliminating the need for a fixed infrastructure of base stations. The communications signals include, for example, voice data that has been modulated according to a desired modulation technique and transmitted as data packets. As can be appreciated by one skilled in the art, network nodes transmit and receive data packet communications in a multiplexed format, such as time-division multiple access (TDMA) format, code-division multiple access (CDMA) format, or frequency-division multiple access (FDMA) format, which enables a single transceiver at the base node to communicate simultaneously with several mobile nodes in its coverage area.
More sophisticated ad-hoc networks are also being developed which, in addition to enabling mobile nodes to communicate with each other as in a conventional ad-hoc network, further enable the mobile nodes to access a fixed network and communicate with other mobile nodes, such as those on the public switched telephone network (PSTN), and on other networks, such as the Internet. Details of these advanced types of ad-hoc networks are described in U.S. patent application Ser. No. 09/897,790 entitled "Ad Hoc Peer-to-Peer Mobile Radio Access System Interfaced to the PSTN and Cellular Networks", filed on Jun. 29,2001, now U.S. Pat. No. 7,072,650, granted on Jul. 04, 2006, in U.S. patent application Ser. No. 09/815,157 entitled "Time Division Protocol for an Ad-Hoc, Peer-to-Peer Radio Network Having Coordinating Channel Access to Shared Parallel Data Channels with Separate Reservation Channel", filed on Mar. 22, 2001, now U.S. Pat. No. 6,807,165, and in U.S. patent application Ser. No. 09/815,164 entitled "Prioritized-Routing for an Ad-Hoc, Peer-to-Peer, Mobile Radio Access System", filed on Mar. 22, 2001, now U.S. Pat. No. 6,873,839, the entire content of each being incorporated herein by reference.
As can be appreciated by one skilled in the art, communication between nodes, however, is often subject to errors due to interference, multipath and fading effects, and collisions. Avoidance of many such errors can be achieved using a control-signal handshake between transmitting and receiving nodes. A communication protocol, such as multiple access with collision avoidance (MACA), uses such a handshake technique between nodes consisting of a request-to-send (RTS) control packet sent from a source node to a destination node which in response, replies with a clear-to-send (CTS) control packet. A multiple access with collision avoidance for wireless (MACAW) algorithm typically handles ARQ retransmissions for corrections of such errors by repeating the whole request-to-send/clear-to-send (RTS/CTS) channel access sequence. In addition, MACAW introduces the use of data-sending (DS) messages to form RTS-CTS-DS-DATA-ACK message exchange and a new backoff algorithm (with the "DATA" being the data and "ACK" being and acknowledgement message).
The Institute of Electrical and Electronics Engineers (IEEE) 802.11 Standard has a mandatory access method, referred to as a distributed coordination function (DCF), which is a form of carrier sense multiple access with collision avoidance (CSMA/CA) that implements both carrier sensing and virtual (RTS-CTS exchange) carrier sensing with acknowledgment messages to improve reliability. As an optional access method, the IEEE 802.11 Standard defines a method known as a point coordination function (PCF), which enables the transmission of time-sensitive information. With PCF, a point coordinator within the access point (AP) controls which stations can transmit during any given period of time. Within a time period called the contention free period, the point coordinator steps through a list of the stations operating in PCF mode and polls them one at a time.
In addition, the media access control (MAC) according to the IEEE 802.11e Standard provides QoS enhancements. That is, the 802.11e Standard QoS technique employs a coordination function called hybrid coordination function (HCF) used only in a QoS enhanced basic service set (QBSS). The HCF has two modes of operation: enhanced distributed channel access (EDCA) and HCF controlled channel access (HCCA). As can be appreciated by one skilled in the art, EDCA is a contention-based channel access function that operates concurrently with HCCA based on a polling mechanism, which is controlled by the hybrid coordinator (HC). The HC is co-located with the QAP (QoS AP), and both types of access (EDCA and HCCA) enhance or extend functionality of the original access methods DCF and PCF. EDCA has been designed for support of prioritized traffic similar to DiffServ (Differentiated Services), which is a protocol for specifying and controlling network traffic by class so that certain types of traffic get precedence, whereas HCCA supports parameterized traffic similar to IntServ (Integrated Services), which is a protocol that attempts to guarantee QoS on networks.
The IEEE 802.11 Standard further introduces the concept of transmission opportunity (TXOP) that is a bounded time interval in which the QSTA (QoS station) is allowed to transmit a series of frames. A TXOP is defined by the start time and a maximum duration. If a TXOP is obtained using the contention-based channel access, it is called an EDCA-TXOP. If a TXOP is granted through HCCA, it is called a HCCA (polled) TXOP. Furthermore, the IEEE 802.11e Standard defines different acknowledgement (ACK) policies between nodes.
Other MAC protocols, such as TDMA based systems, have been proposed for ad-hoc wireless systems to support guaranteed QoS provision. Due to lack of a central controller and high network dynamics, end-to-end reservation schemes or admission control schemes, however, are often not feasible to implement. On the other hand, hop-by-hop channel reservation and traffic control systems may fail to work efficiently if appropriate actions are not taken along the path of the traffic flow. The problem gets more complicated when there are multiple options for MAC protocols along a path since the devices may have multiple transceivers.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.

System and method for providing quality of service provisions and congestion control in a wireless communication network


A breakaway system (10) for detachably connecting a tension transmitting belt (12) to a pin (20) includes a connector (24) having a pair of jaws (34a, 34b) that clamp against the sides of the pin to preload the connector to the pin thereby preventing relative motion between the jaws and the pin. When the tension load acting between the belt and pin exceeds a threshold level, the jaws of the connector spread sufficiently to allow the pin (20) to pass through an exit gap (42) at the ends of the jaws, which gap is of a nominal width that is smaller than the width of the pin.

Various belts, cables, chains and other "line type" devices are used to apply tension loads on enumerous objects. For instance, a carriage may be moved back and forth along a track by a belt connected to the carriage, with the belt being driven by an electric or hydraulic motor. In such installations, it is desirable that the belt be disengageable from the carriage in emergency situations, for instance, if the carriage becomes jammed or the drive motor does not operate properly. Disengagement of the belt from the carriage can avoid significant damage to the carriage structure and/or to the motor used to drive the belt.
A prior art system for connecting the belt to the carriage includes a pin mounted on the carriage and a connector fastened to the end of the drive belt. The connector includes a pair of jaws that have a tip portion that form an exit gap having a width somewhat smaller than the width of the pin. Inboard of the exit gap is an enlarged slot portion of a width significantly larger than the width of the pin. The pin is engaged in the wider slot portion and then tension is placed on the belt so that the pin nominally seats at the innersection of the wider slot portion and the narrower exit gap. When the load on the belt exceeds a threshold level, the jaws separately sufficiently to permit the pin to pass through the exit gap to disengage the jaws. A drawback of this connection system is that when any significant tension load is placed on the belt, the resilient jaws separate somewhat, but not to the extent to allow the pin to disengage from the jaws. As a result, typically constant movement occurs between the jaws and the exterior of the pin whereby the friction forces acting therebetween cause gauling or other detrimental wear between the jaws and the pin leading eventually to failure of the connection system. This and other drawbacks of prior art connection systems are addressed by the present invention.

Breakaway connector system for elements loaded in tension


On a machine for producing at least one continuous cigarette rod, the rod is guided along a given path through a cutting station where it is cut into portions by a cutting device wherein a supporting body, fitted with a counterblade for supporting and guiding the rod, and with a blade movable on the supporting body and through a transverse slit on the counterblade, is moved about an axis crosswise to the path of the rod to move the counterblade along a circular trajectory tangent to the path of the rod at the cutting station.

The present invention relates to a device for cutting continuous cigarette rods.
On cigarette manufacturing machines, at least one continuous cigarette rod is formed and fed axially and continuously through a cutting station where it is cut transversely by a cutting head into a succession of portions for supply to a follow-up, e.g. filter assembly, machine.
On known cigarette manufacturing machines, the cutting station normally comprises a tubular element--hereinafter referred to as a "counterblade"--which is coaxial with the path of the continuous cigarette rod through the cutting station, is movable back and forth in the traveling direction of the cigarette rod, is engaged, in use, in sliding manner by the cigarette rod, and is divided substantially into two integral parts by an intermediate transverse slit through which the cutting head moves during the cutting operation. In other words, just before and during the cutting operation, the counterblade moves in the traveling direction of and at the same speed as the cigarette rod, which is supported on either side of the cut by the two portions of the counterblade, so that the accuracy and neatness of the cut depends on how narrow the transverse slit is.
On most known machines, the counterblade and the cutting head are connected to the ends of respective drives, the only common feature of which is that they are so linked as to enable the counterblade to move with the cigarette rod when this is engaged by the cutting head, normally by means of a blade inclined in relation to the cigarette rod so that, during the cutting operation, the point of contact between the blade and the cigarette rod travels in the same direction and at the same speed as the rod. The fact that the counterblade and the cutting head are connected to different drives inevitably results in a lack of synchronization and, hence, the need for a relatively wide transverse slit in the counterblade.
One solution to the above drawback is proposed in French Patent Application n. 78 29 511, wherein the cutting head is mounted for rotation on a reciprocating support, which travels with the cigarette rod during the cutting operation and supports the counterblade in a fixed position.
Such a solution presents several drawbacks, mainly due to the vibration induced in the machine as a whole by the reciprocating movement of the cutting head, which is relatively heavy.

Device for cutting continuous cigarette rods


Formation of a boron compound is suppressed on the inner wall of a nozzle disposed in a high-temperature region of a process chamber. A semiconductor device manufacturing method comprises forming a boron doped silicon film by simultaneously supplying at least a boron-containing gas as a constituent element and a chlorine-containing gas a constituent element to a gas supply nozzle installed in a process chamber in a manner that concentration of chlorine (Cl) is higher than concentration of boron in the gas supply nozzle.

1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device and a substrate processing apparatus, and more particularly, to a method of manufacturing a semiconductor device and a substrate processing apparatus, which are designed such that formation of boron (B)-compound on a nozzle of the apparatus can be prevented when substrates are processed.
2. Description of the Prior Art
To dope a wafer (silicon substrate) with boron (B) in a general decompression chemical vapor deposition (CVD) apparatus, B2H6 (diborane) gas can be used. For example, when a boron-doped silicon film is formed, B2H6 and a silicon (Si)-compound (silicon-containing gas as a constituent element such as SiH4, Si2H6, and SiH2Cl2) are supplied, and when a Boron-doped silicon germanium film is formed, a germanium (Ge)-compound (Ge-containing gas as a constituent element) is supplied together with B2H6 and a Si-compound, so as to form a B-doped film on the surface of a wafer. Although BCl3 can be used as a boron doping gas instead of B2H6, the use of B2H6 is preferable in that B2H6 does not cause metal contamination because B2H6 does not include chlorine (Cl), and moreover, B2H6 is inexpensive.
In the case where a plurality of wafers are processed by using a vertical or horizontal apparatus, most of B2H6 is consumed by wafers disposed at the upstream side of a process chamber because B2H6 is very reactive, and thus wafers disposed at the downstream side of the process chamber are not properly doped. For this reason, a plurality of nozzles are installed in a manner that the nozzles are disposed at the downstream side as well as the upstream side, so as to improve the uniformity of inter-wafer boron concentration.
However, in the case where nozzles are disposed as described above, if nozzles disposed at a high-temperature region of a process chamber is heated to about 300° C. or higher, B2H6 decomposes thermally in the nozzles to cause deposition of B-compound films on the inner walls of the nozzles. That is, B2H6 is consumed in the nozzles and may not be introduced into the process chamber. Along with this problem, there also arise other problems, such as difficulties in controlling and maintaining the uniformity of inter-wafer boron concentration, and generation of particles caused by B-compound films stripped from the inner walls of the nozzles.

Method of manufacturing semiconductor device and substrate processing apparatus


A cooler assembly for keeping beverages, food, medical supplies, drugs and other heat sensitive products at lower than ambient temperatures. Container includes a radiant heat barrier and air space between an inner and outer shell of a cooler assembly so as to improve the effectiveness of the cooler assembly by minimizing the detrimental effects of radiant heat and conductive heat.

1. Field of Invention
This invention relates to an improved container for holding beverages, food, and other items that require storage at lower than ambient temperatures.
2. Description of the Prior Art
Beverages, food, medical supplies, drugs and other heat sensitive products requiring storage at lower than ambient temperatures have long been kept in insulated "coolers" or "chests." While these coolers or chests have certainly evolved over the years, none of the prior art designs include the necessary features for effectively keeping contents at lower than ambient temperatures by minimizing the detrimental effects of radiant heat.
For instance, U.S. Pat. No. 5,671,611 to Quigley dated Sep. 30, 1997, U.S. Pat. No. 5,568,735 to Newkirk dated Oct. 29, 1996, and U.S. Pat. No. 4,872,589 to Englehart dated Oct. 10, 1989 each address the issue of preventing melted ice from coming into contact with the contents of the cooler and thereby contaminate the contents or allow the contents to become soggy. Though each of the before mentioned patents provides a novel solution to the expressed problem of preventing melted ice from coming into contact with the contents of the cooler, it is not an object of any of the before mentioned inventions to improve the effectiveness of a cooler by minimizing the detrimental effects of radiant heat. Furthermore, the invention described in U.S. Pat. No. 5,568,735 requires that the entire cooler be placed in a freezer until the refrigerant material within the cooler is frozen. This is a disadvantage in that the typical cooler user does not have a freezer large enough to accept even a relatively small cooler, and that freezers are typically unavailable in locations where coolers are often used such as during remote weekend camping trips.
In U.S. Pat. No. 4,537,044 to Putnam dated Aug. 27, 1985, a more effective "hot" or "cold" food storage container is described which could selectively take advantage of the physical movement of heat or cold. Basically, this food storage container is designed so that a cooling source is placed above the food storage compartment for transferring cold in a descending direction while in the cooling mode of operation. Alternatively, a heat source is placed below the food storage compartment for transferring heat in an ascending direction while in the heating mode of operation. Though it is an object of this invention to improve the effectiveness of a cooler in keeping contents hot or cold, this food storage container does not attempt to improve the effectiveness of a cooler by minimizing the detrimental effects of radiant heat.
Yet another invention described in U.S. Pat. No. 4,498,312 to Schlosser dated Feb. 12, 1985 is designed to maintain products at selected hot or cold temperatures through use of solution filled, slab-like containers and a chest or housing. This invention requires that the slab-like containers, which provide the source of heat or cold, be frozen or heated by an external source such as a freezer or oven. While these slab-like containers are removable from the chest or housing and may therefore be easily placed into a typical freezer or oven, freezers or ovens are not usually available during remote weekend camping trips thereby making use of such a container impractical. Furthermore, it is not an object of this invention to improve the effectiveness of a cooler by minimizing the detrimental effects of radiant heat.
U.S. Pat. No. 5,570,588 to Lowe dated Nov. 5, 1996 is similar in operation to that described in U.S. Pat, No. 4,498,312. Specifically, both coolers employ the use of solution filled, slab-like containers or gel-packs to maintain products at desired temperatures. Here again, the invention described in U.S. Pat. No. 5,570,588 would require that the gel-packs, which in this invention provide the source of cold, be frozen by an external source such as a freezer. While these gel-packs are also removable from the chest or housing and may therefore be placed into a typical freezer, freezers are not usually available during remote weekend camping trips thereby making use of such a container impractical. Furthermore, it is not an object of this invention to improve the effectiveness of a cooler by minimizing the detrimental effects of radiant heat.
The picnic cooler described in U.S. Pat. No. 5,064,088 to Steffes dated Nov. 12, 1991 incorporates a novel lid design that includes an integral hinge that separates the lid into portions. The lid can then be removably attached to the cooler container body and access to the cooler container body can be obtained through either portion of the lid. With the exception of the novel lid design and function, the overall cooler is constructed in a manner that is well known in the prior art. That is, the essentially planer lid is hollow, providing very little insulative value, and the cooler container body is comprised of an inner shell, an outer shell, and a low conductivity insulating material. The purpose of this cooler design is to improve the method of operating the cooler by allowing access to the cooler container body in multiple ways, and without the use of hinges or latches. This invention is not intended to improve the efficiency of the cooler in keeping contents at lower than ambient temperature, nor is it an object of this invention to improve the effectiveness of a cooler by minimizing the detrimental effects of radiant heat.
As the above prior art descriptions suggest, there are many difficulties associated in effectively and efficiently storing heat sensitive products, particularly beverages and food items, at lower than ambient temperatures. This is especially true when such items must be kept at lower than ambient temperatures for greater than a twenty-four hour period, and when such items are located in places where no external power source is available. When this is the case, such as during a remote weekend camping trip, the most practical and reliable means for keeping heat sensitive products, particularly beverages and food items, at lower than ambient temperatures is by storing the items in a cooler, and by using ice for maintaining lower than ambient temperatures within the cooler.
Ice is often used as a source of coldness for keeping items in a cooler at lower than ambient temperatures because ice is readily available for purchase, and is relatively inexpensive. It should be noted, however, that the cumulative expense of purchasing ice over extended periods of time, such as during a weekend camping trip, could be significant. Furthermore, it can be disruptive and inconvenient for the cooler user to break away from the pleasures of camping to visit a store or market to purchase additional ice. For these reasons, a cooler that is more effective and efficient at keeping contents at lower than ambient temperatures would be beneficial to consumers.
Most importantly, none of the before mentioned prior art forms attempt to improve the efficiency and effectiveness of a cooler by minimizing the detrimental effects of radiant heat.
Whatever the precise merits, features and advantages of the above cited references, none of them achieves or fulfills the purposes of the present invention.

Cooling container that includes a radiant heat barrier


A method (100) of making an integrated handle (304) on at least one side gusset (308) of a flexible package (300) is provided. The method (100) includes steps of sealing a handle patch (222) on at least one half width of the side gusset laminate (218). Further, the method (100) provides parallel openings on the handle patch (222) such that a centre line of the two parallel openings coincides with centre lines of each half of the side gusset laminate (218). A cover patch (226) is sealed over the handle patch (222) overlapping the edges of the handle patch (222) and simultaneously with the side gusset laminate (218) all around, such that a predefined area is left unsealed between the two parallel openings. The longitudinal edges of the side gusset laminate (218) are folded such that the handle patch (222) comes on the outer surface of the continuous open tube (242) being formed. The continuous open tube (242) is thereby used for manufacturing the flexible package (300).

In the field of flexible packaging for bulk packages (or bags), consumers face problem in carrying the packages from one place to another. The reason being either the bulk packages do not have handle or handles are positioned at the top requiring consumer to lift the longer bags sufficiently so as to prevent it from touching the ground. In these flexible packages consumer also faces problem that the handle being not designed ergonomically so as to help the consumer in dispensing the products.
Handles of these packages are generally located at the top and are attached as a patch which does not provide enough strength for carrying and therefore gets detached most of the time.
Therefore, there exists a need to develop a flexible bulk package and method of manufacturing such flexible bulk packages which can have ergonomically designed handle that is easy to carry and stronger enough which also provide easy carrying of the flexible bulk packages.

Method of making package with integrated handle on side gusset and a package thereof


The vehicle sun visor position retainer is preferably a unitary, flexible, resilient, generally flat piece of plastic, wood, metal, rubber, ceramic or cermet having first and second horizontally extending members. The second member extends laterally of the first member adjacent one end of the first member. The two members are integrally connected together by a step portion which holds the second member below but generally parallel to the first member. The first member contains a generally central vertical hole therethrough adapted to receive the vertical rod portion of a vehicle sun visor bracket. The first member also defines a slot from the periphery of the first member to the hole. Preferably, the slot has outwardly diverging sides. Also preferably, a pair of detents narrow the slot adjacent the hole to hold the first member in place around the rod. Cut-away portions on opposite sides of the detents may increase the effective flexibility. The retainer is horizontally rotatable around the rod between an operative position wherein the second member supports the visor from the underside thereof into an up position out of the way of the vehicle window next to which the visor is installed, and a storage so that the visor can be lowered to shield the eyes from the sun.

1. Field of the Invention
The present invention generally relates to vehicle accessories and more particularly to an improved vehicle visor position retainer.
2. Prior Art
Vehicle windshield visors are normally held in place above the windshield on the interior of the car by a bracket which includes a horizontal arm running through the lower end of the visors and around which the visor can be pivoted between a down, sun-protecting position in front of the windshield and an up-stored position above the windshield. The other parts of the bracket are a vertical arm connected to one end of the horizontal arm, and to an anchor plate adapted to be secured to the vehicle interior at one side of and above the windshield.
Unfortunately, when the visor is heavily loaded with garage door openers, gate openers and sunglass cases, and especially as the visor gets older, it tends to pivot down on its own to the operative position, blocking a view through the windshield. This can be hazardous, especially when it occurs unexpectedly while driving the vehicle. So far as is known to applicant this problem has not been addressed before. It is a problem which needs to be solved. The solution to the problem should be some device which is simple in construction, inexpensive, durable and easy to use. It should provide a positive lock against inadvertant pivoting of the visor, as described above.


A cylinder lock unit is disclosed, with an elongate housing portion (2′) extending outside and along a cylindrical bore, and the elongate housing being dimensioned for being accommodated in a structural part (S) to form a lock device, with a fixed external longitudinal configuration (L) fitting into the structural part. The elongate housing portion has a linear row of cylindrical holes (22′), registering with cylindrical chambers in a key plug having a key slot. The cylindrical holes are closely packed with mutual distances dimensioned in accordance with prescribed minimum standards, and at least one of the cylindrical holes (22′), located adjacent to one longitudinal end of the elongate housing portion (2′), has an inclined cylinder axis, so that, as compared to a lock unit with only mutually parallel cylinder hole axes in the linear row in the elongate housing portion, an extra cylindrical hole is accommodated in the linear row.

In such cylinder lock units, normally being used in very large numbers as door locks and the like, it is important to provide many code combinations, so as to obtain a satisfactory security level of the lock device. Of course, the number of code combinations is dependent, among other things, on the number of cylindrical chambers (equal to the number of cylindrical holes and cylindrical locking pins in the linear row). Normally, in standard lock units, this number is six. A similar prior art lock unit, although the uppermost part of the elongate housing portion thereof is not shorter than the lowermost part of the lock, is known from U.S. Pat. No. 4,294,092.

Cylinder lock unit with an extra locking pin


Ammonium perfluorooctanoate—also called APFO, PFOA or C8—is a surfactant associated with the production of Teflon®, and is also present in products such as fire-fighting foams and may be formed from the microbial degradation of grease-resistant coatings applied to items such as pizza boxes. APFO itself does not hydrolyze, photolyze, or biodegrade under environmental conditions and is biologically additive. A process by which APFO may be removed and recovered from water by electrosorption is discovered. Removal and recovery by electrosorption form an inexpensive and environmentally friendly method of removal and recovery of APFO.

1. Field of the Invention
The present invention relates to the removal and/or recovery of the fluorinated surfactant APFO from water, in particular from drinking or waste water that is contaminated with APFO.
2. Description of the Related Art
Current technology for the removal of APFO from contaminated drinking water utilizes granular activated carbon (GAC). Current technology for the removal of APFO from waste water utilizes either granular activated carbon or ion exchange resins. However, current technology is not 100% efficient at removing extremely low concentrations of APFO. According to page 35 of the February 2006 Report to the Senate Environment Committee titled, "INVESTIGATION OF PERFLUOROCHEMICAL (PFC) CONTAMINATION IN MINNESOTA, PHASE ONE, by Fardin Oliaei, Ph.D., Former Emerging Contaminants Program Coordinator, Don Kriens, M. S., P. E., Principal Engineer, and Katrina Kessler, M. S., Staff Engineer, the activated carbon systems installed for the Cottage Grove, Minn. plant site were only 46% efficient for the removal of APFO.
GAC filters installed in the Mid-Ohio Valley by the DuPont Company in partial settlement of the APFO-contamination class-action lawsuit were expected to have a five-year replacement life, but saturated in less than four months. The use of electrosorption for the removal and recovery of APFO is a new, inexpensive and efficient technique for purification of either drinking or wastewater contaminated with APFO. Felix, et.al. (U.S. Pat. No. 6,613,941) in his development of a method for recovering parts per million of fluorinated alkanoic acids from waste waters, utilized adsorption to an anion-exchange resin as the basis for the removal and recovery process and included electrocoagulation to precipitate colloids interfering with the anion exchange resin. While moderately effective at parts per million concentration levels, these techniques are ineffective at removing the extremely low levels of APFO currently found in drinking water.

Removal and recovery of ammonium perfluorooctanoate (APFO) from contaminated water


A substantially flat key blade extends from a grip portion and has a connecting portion, a major longitudinal bitting portion and a free tip portion. The substantially flat key blade has a cross-sectional profile which, in the major longitudinal bitting portion, is confined within a rectangle having a height, measured in a vertical direction, being at least 2.5 times larger than a width thereof, and extends upwards in the vertical direction from a lower edge surface to an upper edge surface along a vertical mid-plane through the rectangle. A single upper part of the key blade has a relatively small lateral width being no more than 33% of the lower relatively wide part of the key blade and extends obliquely upwards at a relatively small inclinational angle in the interval 3° to 12° relative to a vertical plane.

Key blanks and coded keys, and associated locks forming a cylinder lock and key combination or system, have been developed gradually from a basic design created long ago, namely by Linus Yale Junior in the 1860s, and are still being improved by various measures in order to increase security against the unauthorized opening of the lock and facilitating a rational production of locks and keys in large numbers. A wide-spread overall structure of the keyway, and a substantially flat key blade of a corresponding key or key blank, includes generally a cross-sectional profile consisting of three parts, each having a specific task, viz. a lower relatively wide part, serving mainly to guide the substantially flat key blade in the keyway of the associated lock, an interconnecting part, serving to make it more difficult to manipulate the associated lock, when a key that is not properly cut is inserted into the keyway, and an upper, relatively narrow part having an edge portion serving to position a row of central locking pins of the associated lock into predetermined locations so as to release the lock.
A contemporary example of such a lock and key system is disclosed in the published European patent application EP 3,366,870 A1 (ASSA AB), where the improvement relates to a stop arrangement defining a selectable stop for the full insertion of the substantially flat key blade into the keyway of the plug, wherein the key can be turned and release the cylinder lock. The substantially flat key blade of this prior art key has a cross-sectional profile with several longitudinal grooves and ribs and also several portions that are inclined in relation to the vertical mid-plane of the substantially flat key blade. Similarly, the keyway in the key plug of the associated lock has a corresponding number of longitudinal recesses and ribs, and inclined portions, so that the substantially flat key blade will fit slidingly with some play within the keyway. In the cross-sectional profile of the substantially flat key blade and the corresponding keyway, in the part extending vertically between the lower and upper parts and thus forming an interconnecting part, there are several portions being inclined in alternating directions. The inclinational angles, relative to a central plane, are quite large, so that the adjacent portions will form relatively sharp bends therebetween. This is a type of substantially flat key blade and keyway configuration which is frequently used today in cylinder lock and key systems.
Owing to the bends between the inclined portions of the profiled keyway, the security of the associated lock is enhanced, since it is relatively difficult to reach, from below, the upper part of the keyway, where the lower ends of the locking pins are accommodated when the key has been withdrawn. Thus, it is difficult to observe or find out how to move the locking pins so as to open the lock, and the zig-zag or bent configuration of the interconnecting part of the keyway will therefore deter lock-picking attempts from below, in particular via the lower relatively wide part of the keyway. Of course, the lower relatively wide keyway is a part of the lock which is relatively easy to reach, because of its relatively large width.

Key blank, a key, and a cylinder lock and key combination


A tandem time-of-flight mass spectrometer includes an ion source, a velocity selector downstream of the ion source, a dissociation cell downstream of the velocity selector, and an ion accelerator downstream of the dissociation cell, the accelerator being capable of focusing ions at a space focal plane, and an ion-reflector (reflectron) downstream of the accelerator. The accelerator allows the ions to subsequently separate according to their m/z ratios and the reflectron to subsequently space-focus the ions over a broad mass range at a detector. A velocity selector includes a pair of ion defectors each having multiple electrically conductive strips, the strips including alternate positive voltage strips and alternate negative voltage strips. A method of selecting a subset of ions from a set of ions includes applying a voltage across a first ion deflector so as to deflect ions passing through the first deflector in a first direction away from a flight path, switching off the voltage applied to the first ion deflector in phase with the passage of a subset of ions having a select range of velocities so that the subset of ions is deflected less in the first direction than preceding ions, switching on a voltage applied to a second ion deflector downstream of the first ion deflector so as to deflect ions passing through the second ion deflector in a second direction and to deflect the subset of ions back along the flight path, and maintaining a voltage across the second gate so as to deflect ions following the subset of ions away from the flight path. The velocity selector also can be used in a single-deflector mode.

The invention concerns mass spectrometers, and more specifically tandem time-of-flight mass spectrometers.
Mass spectrometry comprises a broad range of instruments and methodologies that are used to elucidate the structural and chemical properties of molecules, to identify the compounds present in physical and biological matter, and to quantify the chemical substances found in samples of such matter. Mass spectrometers can detect minute quantities of pure substances (regularly, as little as 10xe2x88x9212 g) and, as a consequence, can identify compounds at very low concentrations (one part in 10xe2x88x9212 g) in chemically complex mixtures. Mass spectrometry is a powerful analytical science that is a necessary adjunct to research in every division of natural and biological science and provides valuable information to a wide range of technologically based professions, such as medicine, law enforcement, process control engineering, chemical manufacturing, pharmacy, biotechnology, food processing and testing, and environmental engineering. In these applications, mass spectrometry is used to identify structures of biomolecules, such as carbohydrates, nucleic acids and steroids; sequence biopolymers, such as proteins and oligosaccharides; determine how drugs are used by the body; perform forensic analyses, such as confirmation and quantiation of drugs of abuse; analyze environmental pollutants; determine the age and origins of geochemical and archaeological specimens; identify and quantitate components of complex organic mixtures; and perform ultrasensitive, multi-element analyses of inorganic materials, such as metal alloys and semiconductors.
Mass spectrometers measure the masses of individual molecules that have been converted to gas-phase ions, i.e., to electrically charged molecules in a gaseous state. The principal parts of a typical mass spectrometer are the ion source, mass analyzer, detector, and data handling system. Solid, liquid, or vapor samples are introduced into the ion source where ionization and volatilization occur. The form of the sample and the size and structure of the molecules determine which physical and chemical processes must be used in the ion source to convert the sample into gas-phase ions. To effect ionization, it is necessary to transfer some form of energy to the sample molecules. In most instances, this causes some of the nascent molecular ions to disintegrate (either somewhere in the ion source or just after they exit the ion source) into a variety of fragment ions. Both surviving molecular ions and fragment ions formed in the ion source are passed on to the mass analyzer, which uses electromagnetic forces to sort them according to their mass-to-charge ratios (m/z), or a related mechanical property, such as velocity, momentum, or energy. After they are separated by the analyzer, the ions are successively directed to the detector. The detector generates electrical signals, the magnitudes of which are proportional to the number of ions striking the detector per unit time. The data system records these electrical signals and displays them on a monitor or prints them out in the form of a mass spectrum, i.e., a graph of signal intensity versus m/z. In principle, the pattern of molecular-ion and fragment-ion signals that appear in the mass spectrum of a pure compound constitutes a unique chemical fingerprint from which the compound""s molecular mass and, sometimes, its structure can be deduced.
Tandem Mass Spectrometers
The utility of a mass spectrometric analysis can be significantly enhanced by performing two (or more) stages of mass analysis in tandem. A two-stage instrument is referred to herein as an MS/MS instrument. An MS/MS instrument performs two (or more) independent mass analyses in sequence. In the most frequently used mode of MS/MS, ions of a particular m/z value are selected in the first stage of mass analysis (MS1) from among all the ions of various masses formed in the source. The selected ions (referred to as precursor ions) are energized, usually by collision with a neutral gas molecule, to induce dissociation. The product ions of these dissociations are sorted into a product-ion mass spectrum in the second stage of mass analysis (MS2). If the sample is a pure compound and fragment-forming ionization has been used, individual fragment ions originating in the ion source can be selected as precursor ions; their product-ion spectra (which may be thought of as mass spectra within a mass spectrum) provide much additional structural information about the compound. If the sample is a mixture and nonfragment-forming ionization is used to produce predominantly molecular ions, the second stage of mass analysis can provide an identifying mass spectrum for each component in the mixture.
Independent operation of each stage of mass analysis makes possible other MS/MS operations based on changes in mass, charge, or reactivity and on the ability of the mass spectrometer to define those changes. MS/MS also can be used to substantially improve signal-to-background ratios and, therefore, sensitivity by eliminating interferences in certain types of operations when the ion signal at the m/z of interest is produced by more than one compound. Increasingly, MS/MS is being used to probe more precisely into problems of ion structure as well as to increase resolution in analyses of complex mixtures.
Time-of-Flight Mass Spectrometers
At present, the most widely used mass analyzers are magnetic sectors, quadrupole mass filters, quadrupole ion traps, Fourier-transform ion-cyclotron resonance cells, and time-of-flight (TOF) tubes. TOF mass analyzers are fundamentally the simplest and the least expensive to manufacture. They separate ions by virtue of their different flight times over a known distance. To create these different times, an ensemble of ions of like charge are accelerated to essentially equal kinetic energies and, in a brief burst, released from the ion source into the flight tube. Since an ion""s kinetic energy is equal to xc2xd mv2 (where m is its mass and v its velocity) and all ions of like charge have substantially the same energy, light ions will have greater velocities and, consequently, shorter flight times to the detector than heavy ions. The m/z values of each set of ions contained in a given burst out of the ion source can be determined by measuring their successive transit times from the ion source through the flight tube to the detector (typically several tens of microseconds).
A TOF mass spectrometer is unique in that its m/z-range is theoretically unlimited, and its mass spectra are not produced by scanning. Moreover, it is a relatively simple, inexpensive instrument to manufacture and operate. These three features account in large part for the major role TOF instruments have played in the rapidly expanding usage of mass spectrometry in molecular-biological research and biotechnology.
With the other four commonly used mass analyzers, the settings of one or more parameters determines the m/z of the ions that are allowed to pass to the detector. In order for ions with a different m/z to be detected, these settings must be increased or decreased. Ultimately, some fundamental or practical characteristic of the mass analyzer limits the extent to which its m/z-determining parameters can be changed to accommodate analysis of increasingly larger ions. In a TOF mass analyzer, increasingly larger ions simply take increasingly longer times to reach the detector, and there is no limit to the length of time that can be measured. Thus, TOF mass analyzers are especially useful for the analysis of large biological molecules.
Scanning denotes a continuous increasing or decreasing of a mass analyzer""s m/z-determining parameters over a predetermined range so that ions over a corresponding range of m/z-values can be detected in succession. The analytical efficiency of a mass spectrometric analysis is greatly reduced by scanning because, while the ions of one particular m/z are being detected, the ions of all other m/z-values released from the ion source are being irretrievably lost in the instrument. With TOF mass analyzers, by contrast, all of the ions released in an ion-burst from the source are detected and recorded without changing any instrumental parameters. Consequently, TOF mass spectrometers are particularly sensitive instruments.
TOF mass spectrometers may be constructed using relatively simple components, such as accelerators, ion reflectors, and ion detectors. Moreover, TOF mass spectrometers are relatively simple to operate because they are stable in operation and the components require minimal tuning. Because of their relatively simple construction and operation, TOF mass spectrometers are relatively inexpensive to construct and operate.
Referring to FIG. 1, a typical time-of-flight mass spectrometer includes an ion source, a drift region, and a detector. Ion sources have two components: an ionization chamber and an ion extractor/accelerator. A sample is received in the ionization chamber, volatilized if necessary, and ionized (usually by some is energetic process). An ionization process that is particularly suited for large biological molecules is matrix-assisted laser desorption/ionization (MALDI). MALDI requires that the sample be dispersed within a matrix of solid, crystalline material. A laser is focused on the sample to volatilize and ionize the sample. The process also may cause a portion of the resulting ions to dissociate into smaller fragment ions. Those of ordinary skill in the art are familiar with the construction and operation of MALDI sources.
Focusing Ions
In general, ions formed in a TOF ion source have different times of formation, initial positions and velocities. Without some form of correction, these variations in the ions"" initial mechanical properties diminish the resolution of the mass-dependant bands that are later detected. The uncertainties associated with these variations can be corrected one at a time, but it is very difficult with a single device to correct for two or more of them simultaneously. Wiley and McLaren developed a two-stage ion source that, with certain restrictions, can force ions having the same mass-to-charge but different initial positions or velocities to arrive nearly simultaneously at a particular plane some distance downstream of the ion source. [Wiley, W. C.; McLaren, I. H.; Review of Scientific Instruments, Vol. 26:12, pp. 1150-1157 (1955), which is incorporated herein by reference]. The position of this plane, which is referred to as the space focal plane, is uniquely defined by the ion source""s geometry, and the voltage applied to the ion source""s electrodes. [Potter, R. J.; xe2x80x9cTime-of-Flight Mass Spectrometry,xe2x80x9d American Chemical Society, Washington, D.C., (1997), which is incorporated herein by reference.] In a Wiley/McLaren two-stage source, the ionization chamber (or ionization region) is separated from the accelerating region by a plane grid. The electric field in the ionization region (or first stage) is made smaller than in the accelerating region electric field by adjusting the voltages applied to the sources backing plate and to the grid separating the two regions. Ions move from the ionization region, into the acceleration region, and out of the source under the influence of these electric fields. Ions can be generated in the ionization chamber or injected into it. After a short time delay the electric field in the ionization region is switched on. This electric field moves the ions out of the first stage into the second stage where they are accelerated to greater velocities.
By means of time-lag focusing, the two-stage ion source is able to correct for variation in the initial velocities of the ions providing they are formed in, or nearly in, a plane that is parallel to the backing plate and the dividing grid. During the lag period xcfx84, the ions spread out in the ionization chamber in accordance with their velocities at the time of their formation. Those ions that are closer to the backing plate when the electric field is switched on (lagging ions) are accelerated over a longer distance before entering the second stage than ions farther from the backing plate (leading ions). Thus, the lagging ions receive more kinetic energy from the first electric field than the leading ions. Consequently, the lagging ions eventually catch up with leading ions of the same m/z. At the plane where the lagging ions catch the leading ions of the same m/z, the ions are said to be energy-focused. The time lag energy focal plane of an ion source coincides with that ion source""s space focal plane. The distance from the exit of the accelerating region to the plane where space focusing occurs is referred to as the space-focal length f. Under a fixed set of conditions, f is mass dependent so ions of different masses will have different focal lengths. In a given mass spectrometer, the distance from the exit of the accelerating region to any ion-optical component downstream of the ion source, e.g., velocity selector, post velocity selection accelerator, ion reflector, or ion detector, is fixed by the instrument""s geometry. The focal length for ions of any particular mass can always be made equal to any of these fixed distances by adjusting the ratio Ea/Ee of the electric fields in the accelerating region (Ea) and the extraction region (Ee) and, in the case of time-lag-focusing, the delay or lag time xcfx84. Because the dimensions of these regions are fixed for a given ion source, Ea/Ee is varied by changing the voltages applied to the repeller plate and the extractor/accelerator grid that separates the two regions.
Tandem Time-of-Flight Mass Spectrometers
TOF mass spectrometry""s steadily growing range of application in biomolecular analysis has prompted several attempts to develop tandem TOF instruments. Two approaches have been taken: 1) coupling two independently usable mass spectrometers together; and 2) using velocity selection as the basis for the first stage of mass spectrometry in the tandem sequence of operations. The first is classical and general to all forms of mass spectrometry. The second is recent and specific to time-of-flight mass spectrometers. The classical approach to constructing a tandem TOF mass spectrometer has so far produced three instrument forms: 1) a high-resolution TOF mass analyzer coupled to a high resolution TOF mass analyzer (TOF/TOF); 2) a double-focusing sector mass analyzer coupled to a high resolution TOF mass analyzer (Sector/TOF); and 3) a quadrupole mass filter coupled to a high- resolution TOF mass analyzer (Q/TOF). These instruments produce mass spectra that exhibit unit mass-resolution Q/TOF) or better (TOF/TOF and Sector/TOF) in the first stage of mass analysis (MS1). In the cases of TOF/TOF and Sector/TOF, the gain in MS1-resolution is offset by low sensitivity because, in instances where PSD is the predominant fragmentation process, very few precursors reach the collision cell and the second stage of mass analysis (MS2) or, in instances where the collision cell must be used to induce fragmentation, the collisional dissociation process interferes with the timing and transmissions of the MS2-TOF. Either way, the performance and, hence, utility of these tandem instruments are degraded.
Q/TOF instruments are manufactured by two companies: Micromass Ltd., Floats Road, Wythenshawe, Manchester M23 9LZ, UK; and PE SEIEX, Concord, Ontario, L4K 4V8, Canada. Unfortunately, the gain in the Q/TOF""s MS1-performance is offset by the fact that only low energy ions (10-40 eV) can be analyzed by MS1. This restriction excludes ions produced by MALDI, which is one of the most versatile and widely used ionization methods.
The velocity selection approach to configuring a tandem TOF mass spectrometer takes advantage of the fact that product-ions resulting from metastable or induced decompositions in a time-of-flight tube retain to the first order the velocity of their precursors (parent ions). This approach is appealing because it offers a means to preserve much of the single TOF mass analyzer""s sensitivity and simplicity. The reality to date, however, is that tandem TOF configurations based strictly on velocity selection in MS1 do not. achieve analytically useful resolution in MS1, MS2, or both. To the extent they have succeeded, such instruments have sacrificed one or more of the TOF mass analyzer""s three advantageous features: theoretically unlimited mass range, recording without scanning, and simple and inexpensive construction and operation.
The post-source decay (PSD) method introduced by Kaufmann et al. [Kaufmann, R.; Spengler, B.; Lxc3xctzenkirchen, F. Rapid Communications in Mass Spectrometry, 7:902-10 (1993); Kaufmann, R., Kirsch, D., Spengler, B., International Journal of Mass, Spectrometry and Ion Processes, Vol. 131:355-85 (1994)], presently is the most widely used form of tandem TOF mass spectrometry based on velocity selection. In addition to being hampered by the general technological failings of current velocity selection configurations, PSD suffers the additional drawback of being inextricably coupled to the MALDI ionization technique. More generally, PSD relies exclusively on the statistically governed processes of metastable decomposition and random gas-phase collisions during flight to produce fragment ions for analysis in MS2. Each of these phenomena tend to be promoted in several compounds under MALDI conditions; hence, the almost inseparable association between PSD and MALDI. When metastable and gas-phase decompositions are not promoted by MALDI (as is often the case with important compounds), PSD provides no recourse to any other means for producing fragment ions.
Tandem time-of-flight mass spectrometers that use velocity selection as the basis for MS1 employ ion deflectors as gates for selecting a band of ions having a desired m/z. The classical geometry for such a gate uses a pair of parallel plates to define a uniform electric field perpendicular to the flight path of the ions. When the electric field is on, it deflects ions that enter the gate so that they do not reach the detector. When the ions to be selected reach the gate, the electric field is switched off to allow those ions to pass through. As soon as the desired ions have passed through the gate, the electric field is switched back on so that ions subsequently entering the gate also are deflected. Parallel plate velocity selectors have relatively large capacitances (5-10 pf); therefore, they are difficult to switch on and off in less than 30-50 ms; shorter switching times are necessary to produce high enough resolving powers (m/xcex94m, where m is the mass of the select ions and xcex94m is the range of masses selected) to be effective in tandem TOF mass spectrometers.
A more effective gate geometry than parallel plates is an arrangement of parallel wires. Wires have less capacitance than plates (xe2x89xa6pf) and can be switched in 5-10 nanoseconds; however, they impart less deflection impulse to passing ions.
Some have achieved slightly better resolutions using dual deflector velocity selectors. With such velocity selectors, the first deflector is initially on so as to deflect ions passing through it, and the second deflector located downstream of the first is initially off. When the desired ions approach, the first deflector is switched off to allow them to pass through without being deflected. As soon as the selected ions pass through the second deflector, again without being deflected, the second deflector is switched on. Although it is possible to make the time between when the first deflector is switched off and the second deflector is switched on smaller than the time it takes to turn a single deflector off and then back on again, dual deflectors operated in this manner have not been able to provide high enough resolving powers to operate very effectively as velocity selectors in tandem TOF mass spectrometers.
If one can ignore the tiny amount of energy released when a molecular ion decays in the flight tube of a TOF instrument, conservation of energy and momentum require that the fragments of the decay (both charged and neutral) continue flight with exactly the same velocity their parent had. Therefore, when particles are selected in the flight tube on the basis of velocity, the selected group can contain nondissociated precursors, fragments of dissociated precursors, or both. If the group does contain nondissociated precursors and some or all of these do dissociate in the length of flight tube remaining between MS1 and MS2, the fragments of those decays would simply continue to fly along with the selected group. Hence, the velocity-selected group of particles enters MS2 of a tandem TOF instrument as a spatially and temporally confined band. At this stage, the kinetic energies of the fragments are proportional to their masses, and the maximum kinetic energy for any fragment equals that of the nondissociated precursor ions, qVion source (where q is the charge carried by a precursor ion). For example, the kinetic energies of the fragments of a 20 keV, 3000 Da precursor ion would essentially cover the range 0-20 keV (1 Da={fraction (1/12)} of the mass of a single atom of 12C).
In order to separate particles with identical velocities but different energies, the particles must be accelerated. In current tandem TOF instruments, ion reflection is used to accomplish this task. The selected group (fragments and ions that have not fragmented) are directed into an ion reflector (ion mirror or reflectron), which is the main component of MS2. A typical linear-field reflectron creates a highly uniform axial electric field that accelerates the ions in a direction exactly opposed to the direction of their entry. Thus, ions entering the reflectron at a particular angle of incidence xcfx86 are gradually slowed to a stop and then gradually speeded up in the direction from which they came so that they exit the mirror at a reflected angle exactly equal to xcfx86. Providing xcfx86 is not too large ( less than 2 or 3xc2x0), a typical linear-field reflectron is able to focus ions at a space focal plane, located some distance from the exit of the reflectron where a detector is normally mounted. The reflectron will only focus ions of the same mass at its space focal plane if those ions were spaced-focused at its object plane prior to entering it. The neutral fragments in the selected group are not acted upon by electric fields and, therefore, pass straight though the reflectron; the neutrals can be recorded by a detector placed beyond the rear of the reflectron.
Ions entering the reflectron with more kinetic energy will penetrate deeper into the reflectron than ions entering the reflectron with less kinetic energy. Because fragment ions always have less energy than their parent ions, fragment ions exit the reflectron more quickly and reach the detector sooner than their precursors. Not all of these fragment ions will be space-focused at the plane of the detector. Only those ions that require 85-95% of the length of the ion mirror to be reflected will be space-focused when they arrive at the detector. Ions with less energy (lighter ions) will penetrate less deeply into the reflectron and will not be space-focused at the detector. Thus, dispersion by ion reflection can only produce a complete mass spectrum of the fragment ions, similar to one that would be produced by a tandem mass spectrometer, when the voltage of the reflectron is stepped. A partial spectrum is produced with each step, and the partial spectra are assembled in order to produce the complete spectrum. For example, a spectrum covering the mass-range of the product ions of the 20 keV, 3000 Da precursor ion described above can be acquired on existing instruments equipped with a single stage, linear-field reflectron by stepping the reflectron""s voltage setting 7-10 times (10-14 times with a double stage ion-reflectron) and recording a segment of the spectrum at each setting. The TOF mass analyzer""s highly valued nonscanning feature is sacrificed when it becomes necessary to resort to this time-consuming, sample-wasting, manual stepping procedure.
Cotter""s U.S. Pat. No. 5,464,985 discloses a tandem TOF mass spectrometer. Cotter""s spectrometer selects precursor ions in MS1 according to their velocity and disperses the fragment ions and nondissociated precursor ions with a reflectron. Cotter avoids the linear reflectrons limited mass range problem by using a curved-field reflectron to record an entire spectrum at a single voltage setting. The curved-field reflectron uses a nonlinear axial electric field to achieve focusing across a wide mass range of product ions without stepping or otherwise changing the reflectron""s voltage setting. Despite its elegant conception, the curved-field reflectron is not practical. The curved-field reflectron, which consists of 86 ring elements (instead of 30 or so for a simple linear-field reflectron) connected by 85, 20-turn, 2 Mxcexa9 potentiometers (instead of 29 or so uniform fixed resistors), is difficult to construct, is difficult to tune (each potentiometer must be painstakingly adjusted to precisely replicate the required curvature in the axial component of its electric field), is difficult to maintain in tune because of non-uniform drift in the potentiometers"" settings, and has low ion-transmission because of the defocusing action of the unavoidable radial component of its electric field. Thus, the TOF mass analyzer""s stable operation and simple, low-cost construction are sacrificed in Cotter""s spectrometer.
The present invention overcomes the problems discussed above. The invention provides a tandem time-of-flight mass spectrometer that includes an ion source, an ion selector downstream of the ion source, a dissociation cell downstream of the ion selector, an ion accelerator downstream of the dissociation cell, an ion reflector (ion mirror or reflectron) downstream of the accelerator, a detector that records neutrals and ions transmitted through the reflectron, and a detector that records ions reflected by the reflectron. The spectrometer of the present invention is stable in operation, simple in construction, has high resolving powers, and is able to focus product ions at a space focal plane located at a detector.
In one embodiment of the invention, the mass spectrometer includes an ion source, a velocity selector downstream of the ion source, a dissociation cell downstream of the velocity selector, an ion accelerator downstream of the dissociation cell, the accelerator being capable of focusing ions at a first space focal plane, a reflectron downstream of the accelerator, the reflectron defining an object plane located at the first space focal plane, and the reflectron being capable of focusing ions at a second space focal plane, and an ion detector located at the second space focal plane. The position of the accelerator in this embodiment is particularly advantageous because it accelerates the product ions in a manner that minimizes the effects of the uncertainties of ions leaving the dissociation cell, allows the ions to subsequently separate according to their m/z ratios, and allows the ions to be easily focused at a detector.
The invention also provides a method for producing a mass spectrum that includes accelerating a set of ions to give the set of ions mass-dependant velocities, selecting a subset of the set of ions based on their velocities, inducing dissociation of a fraction of the selected subset of ions if necessary, and detecting the subset of ions. In one embodiment, the method of producing a mass spectrum includes ionizing a material to produce a set of ions. The set of ions is then accelerated to a constant energy so that each ion has a mass-dependant velocity. The accelerated set of ions is allowed to drift along a flight path so that subsets of ions within the set of ions that have different velocities become spatially separated along the flight path. The set of ions, except a select subset of the ions within a narrow, select velocity range, are subsequently deflected from the flight path. In one embodiment, a fraction of the subset of select ions are then induced to dissociate, and the resulting fragment ions along with the remainder of nondissociated ions in the original subset of ions are accelerated along the flight path to mass-dependant velocities, allowed to drift along the flight path so that ions of different velocities spatially separate, and detected at a location along the flight path. The acceleration of the subset of ions along the flight path after the ions dissociate allows the ions to subsequently separate according to their m/z ratios and allows them to be easily focused onto a detector. In one embodiment, the subset of ions are accelerated by an electric field that is switched on once all the ions have moved into the space between the electrodes that create the field, so that the subset of ions will focus at a space focal plane.
The invention also provides a novel velocity selector that is able to attain high resolving powers. A high resolving power corresponds to the selection of a very small range of velocities and, therefore a very small range of masses. An embodiment of the velocity selector includes a first ion deflector having multiple, electrically conductive strips that define multiple channels. The strips include alternate positive voltage strips connected to a first positive voltage source, and alternate negative voltage strips connected to a first negative voltage source. A second ion deflector is in series with the first ion deflector. The second ion deflector includes multiple, electrically conductive strips defining multiple channels. The strips include alternate positive voltage strips connected to a second positive voltage source, and alternate negative voltage strips connected to a second negative voltage source. The strips can impart sufficient deflection impulse to passing ions, and yet their low capacitance enables short switching times.
The invention also provides a method for selecting a subset of ions from a set of ions. In one embodiment, the method includes accelerating a set of ions in the ion source so the ions have varying velocities, and allowing the set of ions to move along a flight path so that ions of different velocities spatially separate along the flight path. A voltage is applied across a first ion deflector positioned along the flight path so as to deflect ions passing through the first deflector in a first direction away from the flight path. The voltage across the first deflector is switched off so that a subset of ions having a select range of velocities is deflected less in the first direction than preceding ions, and a voltage across a second ion deflector arranged downstream of the first deflector switched on so as to deflect ions passing through the second deflector in a second direction, which is exactly opposite the first direction. The voltages and switching times are such that the second deflector deflects the subset of ions with the select velocity back along the flight path but deflects ions following the subset of ions with the select velocity away from the flight path in the second direction. The method of ion selection produces particularly high resolving powers because it allows the electric fields generated by the deflectors to interact dynamically with the subset of ions with the select velocity as they pass through the deflectors.

The State of Oregon acting by and through the State Board of Higher Education on Behalf of Oregon State University


The invention is a system and method for propellantless, ultrahigh precision satellite formation flying based on ultrahigh precision intracavity laser thrusters and tethers with an intersatellite distance accuracy of nanometers at maximum estimated distances of tens of kilometers. The repelling force of the intracavity laser thruster and the attracting force of tether tension between satellites form the basic forces to stabilize matrix structures of satellites. Users of the present invention can also use the laser thruster for ultrahigh precision laser interferometric metrology, resulting in simplification and payload weight reduction in integrating the thruster system and the metrology system.

The advent of micro-satellite and nano-satellite technology has provided an opportunity to insert sophisticated sensors and processing technologies into orbits of interest at low costs. Building a cluster of small satellites is generally cheaper, more robust, and more versatile than building one, large, monolithic satellite. Additionally, precision formation flying is critical to enable remote sensing space stations to improve both resolution and surface area coverage by orders of magnitude. Another advantage to precision formation flying of multiple nano-satellites is that it allows launch vehicles with small size limitations to assemble large, steady mirror apertures or large sample collection areas. For example, ultrahigh precision satellite clusters can be used for advanced geophysical monitoring to measure and monitor small changes in the movement of earthquake plates and gravity wave detection, whereas current GPS and standard laser range finders cannot. In another example, ultrahigh precision satellite clusters can be used for structuring large space telescopes and spectrometers for observing and characterizing earth-bound activities as well as near-earth orbit asteroids and comets.
Technology that depends on formation flying of nano-satellites critically depends on creating and maintaining precise formations. The least stringent requirements may require two satellites meters apart to maintain distance accuracy of 1 centimeter and a relative bearing of 1 arcminute while the most stringent requirements may require multiple satellites stationed kilometers apart to maintain distance accuracy of 1 nanometer and a relative bearing of 1 micro-arcsecond.
For example, one of the most challenging applications for formation flying thus far is that of the proposed MicroArcsecond X-ray Imaging Mission (MAXIM) project. According to the full MAXIM concept, the relative distance between the hub satellite and collector satellites needs to be precisely maintained within a few nanometers tolerance with a distance of approximately 200 meters between the satellites. The provision requirement for maintaining this distance, therefore, is 10 parts per trillion distance units. Most of the conventional propellant-based propulsion systems would not be able to handle this type of precision, such as gas hydrazine thrusters, pulsed plasma thrusters, hall thrusters, electrostatic ion engines, and field emission electron propulsion systems. Additionally, even if such thrusters were minimized to provide smaller, more accurate bursts of thrust, there remains a strong concern that the resulting propellant exhaust plumes may contaminate sensors and associated windows and optics.
To alleviate these concerns, several propellant-less formation flying methods have been proposed. Propulsive conducting tethers and spin-stabilized tether systems have been proposed in place of on-board propulsion systems to form and maintain satellite formations. Additional minimal thrust requirements can be handled through techniques such as the microwave scattering concept, the Coulomb force concept, and the magnetic dipole interaction concept. While such concepts offer intriguing possibilities for small arrays consisting of only a few spacecraft, implementing a system for dozens of satellites over large distances quickly becomes problematic.
For example, microwave scattering requires very high power consumption, requires large antenna arrays, and the scattered microwaves may electronically interfere with neighboring satellites. The Coulomb control system is limited to close formation (less than 50 m) plasma environments characterized by Debye lengths greater than the inter-vehicle separation, and requires very high voltage discharges which, in addition to consuming large amounts of energy, can damage instruments or throw off the accuracy of such instruments due to electrostatic discharge. The magnetic dipole interaction concept also requires close formations, and requires a very bulky and heavy system on the magnitude of several tons.
Therefore, there is a need in the art for a system and method to implement a system and a method for implementing satellite formation flying which is propellant-less, requires low power, is lightweight, uses little space, and provides for ultrahigh precision control of the distance and bearing between satellites.

System and method for propellantless photon tether formation flight


A camera device is provided which has a compound eye structure only by a liquid lens unit and a control unit without requiring a plurality of lenses to be mounted in advance and is capable of taking a three-dimensional stereoscopic video image. In addition, a compact and lightweight three-dimensional stereoscopic camera is provided which can be switched to take a two-dimensional planar image or to take a three-dimensional stereoscopic image only by an electronic control with no need for a movable mechanism and can reduce the power consumption and improve the reliability. A camera device comprises a liquid lens (182) switchable to a single eye lens and a compound eye lens; and a switching unit for switching the liquid lens (182) to the single eye lens to take a planar image and switching the liquid lens (182) to the compound eye lens to take a stereoscopic image.

A conventional camera capable of obtaining planar image information and stereoscopic image information is, for example, a 3D camera described in Patent Document 1 specified below.
FIG. 10 is an external view of a conventional 3D camera 910 including two camera heads, i.e., a fixed head 915 and a movable head 916, and FIG. 11 is a block structural diagram of a main part of the 3D camera 910.
The fixed head 915 is fixed to a main body of the 3D camera 910, whereas the movable head 916 can be slid and thus moved by operating a moving button 912. In FIG. 10, the movable head 916 is shown in the state of having been moved to an outermost position in a movable range thereof. In FIG. 11, reference numeral 916 represents the movable head in the state of having been moved to the outermost position in the movable range thereof, and reference numeral 916′ represents the movable head in the state of having been moved to an innermost position in the movable range thereof.
The fixed head 915 and the movable head 916 respectively include a fixed head lens 917 and a movable head lens 918. The fixed head lens 917 and the movable head lens 918 are respectively zoomed in or out by a zoom motor 926 and a zoom motor 929 described later.
The fixed head 915 and the movable head 916 respectively have an optical axis 937 and an optical axis 938 which are parallel to each other regardless of a gap therebetween. The fixed head 915 and the movable head 916 each include a charge coupled device (CCD) sensor, which is an image pickup element. The fixed head 915 and the movable head 916 are substantially identical with each other, and located in a common plane which is vertical to the optical axis 937 and the optical axis 938.
The movable head 916 is structured to be slidable and thus movable in the state where the optical axis 937 and the optical axis 938 are kept parallel to each other and both of the movable head 916 and the fixed head 915 are located in a plane vertical to these two optical axes.
The fixed head 915 and the movable head 916 are controllable by a user. For example, the user may press the moving button 912 located in an upper part of the movable head 916 with his/her finger to slide and thus mechanically move the movable head 916. Alternatively, the user may rotate a dial 913 connected to the movable head 916 via a worm gear to adjust the gap between the fixed head 915 and the movable head 916. In another example, the user may rotate a motor with an electronically controllable button switch or the like, such as a rightward moving button and a leftward moving button, to move the movable head 916.
The position of the movable head 916 is measured by a position encoder 925 and is input to a vision feedback unit 932, which is a circuit for determining a field of view and a focal distance of each of the fixed head lens 917 and the movable head lens 918. The position encoder 925 includes a linear potentiometer for detecting the position of the movable head 916. In another example, the movable head 916 may be moved by a stepper motor and the position thereof may be measured by counting the number of steps of the motor.
The vision feedback unit 932 controls a zoom control unit 924 in order to adjust the focal distance of each of the fixed head lens 917 and the movable head lens 918. The zoom control unit 924 controls the zoom motor 926 and the zoom motor 929. At this point, the focal distances are controlled to maintain the same value with each other.
The vision feedback unit 932 also receives detailed information on a display unit 933 for displaying a captured image from a display unit element determination unit 930. This information is, for example, a preset value indicating a screen size or a prescribed observing distance of the display unit 933. Alternatively, the user may input appropriate data as such information.
The vision feedback unit 932 further receives subject depth information from a subject depth determination unit 931. The subject depth determination unit 931, in a simplest structure thereof, may merely set an apocenter to infinity and set a pericenter to a minimum focal distance of the camera. In a more advanced example, for instance, where the camera is of an autofocus type, one or more depth range limit values may be measured by an autofocus sensor. In order to maximize the flexibility, the auto focus sensor is directed to the closest point or the farthest point in the image to be captured and thus accurately measured distance data is supplied to the vision feedback unit 932.
In addition to controlling the zoom motor 926 and the zoom motor 929 to adjust the focal distance of each of the fixed head lens 917 and the movable head lens 918, the zoom control unit 924 supplies the vision feedback unit 932 with information indicating whether or not the camera of the fixed head 915 and the camera of the movable head 916 operate within tolerable conditions. For example, when a maximum parallax condition is exceeded, the zoom control unit 924 notifies the vision feedback unit 932 that an image which will be captured with the current camera setting is inappropriate. The vision feedback unit 932 notifies the user of this through information which is displayed on the display unit 933. Similarly, when the depth of a captured image is too small, the zoom control unit 924 may provide a display indicating that good 3D perception will not be obtained.
An image captured by the image pickup element of each of the fixed head 915 and the movable head 916 is sent to an image processing unit 934. The image processing unit 934 processes the captured image based on data sent from the zoom control unit 924 or the vision feedback unit 932, and displays the resultant image on the display unit 933.
Alternatively, a post-processing or pre-processing image may be stored on a fixed or detachable memory 935. In the case of the detachable memory 935, the memory 935 may be transferred to another device to transfer the image to the another device, for example, a computer or a three-dimensional projector. In this manner, the image may be subjected to other types of processing or stereoscopic display.
In the case where, for example, the 3D camera 910 includes a communication unit (not shown), the communication unit may be used to transfer the image to an other device, for example, a computer or a three-dimensional projector. In this manner, the image may be subjected to other types of processing or stereoscopic display.
The vision feedback unit 932 receives information indicating the position of the movable head 916 and the gap between the fixed head 915 and the movable head 916 from the position encoder 925. The vision feedback unit 932 also receives information indicating the focal distance of each of the lens of the fixed head 915 and the lens of the movable head 916 from the zoom control unit 924, and determines the field of view of the camera based on both of the information regarding the focal distances and the information regarding the gap between the fixed head 915 and the movable head 916. For example, where the fixed head 915 and the movable head 916 have a maximum gap therebetween, the focal distances of the fixed head lens 917 and the movable head lens 918 are adjusted such that the camera has the widest field of view. By contrast, where the gap between the fixed head 915 and the movable head 916 is set to be minimum, the fixed head lens 917 and the movable head lens 918 are controlled such that the camera has the narrowest field of view within a usable range.
conventional liquid lens which uses a liquid as a lens material and is capable of changing a focal distance thereof by an electronic control is, for example, a liquid microlens described in Patent Document 2 specified below.
FIG. 12 is a cross-sectional view of such a conventional liquid microlens 960.
The liquid microlens 960 includes a droplet 962 formed of a transparent liquid. The droplet 962 has a diameter of several micrometers to several millimeters. The droplet 962 is located on a transparent substrate 964. The transparent substrate 964 is hydrophobic or has a hydrophobic coating layer. Accordingly, the droplet 962 has a very strong interface tension to the transparent substrate 964, and if being left without being processed, tends to be shaped spherical as a result of being "repelled" by the transparent substrate 964. However, by an electromagnetic control of applying a predetermined voltage between the droplet 962 and the transparent substrate 964, the interface tension of the droplet 962 to the transparent substrate 964 can be weakened by an electron wettability phenomenon. As a result, a lens in which an angle of an end of the droplet 962 with respect to the transparent substrate 964 is θ can be formed.
The transparent liquid which forms the droplet 962 and the transparent substrate 964 are transparent with respect to light having a wavelength in a certain range including visual light rays.
Light rays 966, which are incident on the liquid microlens 960 and are vertical to the transparent substrate 964 and parallel to each other, pass the liquid microlens 960 and are collected to a focal point 968 which is distance f away from the contact face of the droplet 962 and the transparent substrate 964.
Contact angle "θ" between the droplet 962 and the transparent substrate 964 is determined by interface tension "Y" mentioned below (usually measured with millinewton per meter (mN/m)).
In the liquid microlens 960, the angle θ is represented by expression 1 where YS-V is the interface tension between the transparent substrate 964 and air (or a gas or another fluid) enclosing the transparent substrate 964, YL-V is the interface tension between the droplet 962 and air (or a gas or another fluid) enclosing the droplet 962, and YS-L is the interface tension between the transparent substrate 964 and the droplet 962.
                              cos                                (            θ            )                          =                                            Y                              S                -                V                                      -                          Y                              S                -                L                                                          Y                          L              -              V                                                          [                  Expression                                                              1                ]
Where the volume of the droplet 962 is V, the radius of curvature "R" of the curved surface of the droplet 962 is represented by expression 2.
                              R          3                =                              3            ·            V                                                              π                                                  (                                      1                    -                                          cos                                                                                θ                                                        )                                                                          (                                  2                  -                                                            cos                      2                                                            θ                                    -                                      cos                                                                                θ                                                  )                                                                                [                  Expression                                                              2                ]
The focal distance f of the liquid microlens 960 is the function of the radius R and the refractive index "n".
Where nL is the refractive index of the droplet 962 and nV is the refractive index of air (or a gas or another fluid) enclosing the droplet 962, the focal distance f is represented by expression 3.
                    f        =                  R                                    n              L                        -                          n              V                                                          [                  Expression                                                              3                ]
Since a top surface and a bottom surface of the transparent substrate 964 are parallel to each other, refractive index thereof is not an issue. Where the volume V of the droplet 962, the refractive index nL of the droplet 962, and the refractive index nV of the air enclosing the droplet 962 are assumed to be constant (usually, V, nL and nV are considered to be constant), the focal distance of the liquid microlens 960 is the function of only the contact angle θ.
FIG. 13 is a schematic view of an electronic wettability phenomenon. By this electronic wettability phenomenon, contact angle θ1-θ2 between the droplet 962, which is a conductive fluid, and a dielectric insulating layer 974 having a dielectric constant of "εγ" and a thickness of "d" can be reversibly changed. Therefore, a liquid microlens, the focal distance of which is reversibly changeable, can be provided.
As shown in FIG. 13, a metal electrode 976 is located below the dielectric insulating layer 974, and is insulated by the dielectric insulating layer 974 from a droplet 972, which is a conductive fluid. The droplet 972 is, for example, a small water drop, and the dielectric insulating layer 974 is, for example, a thin film or a thin plate formed of Teflon (registered trademark)/Parylene as a material.
Without any voltage difference between the droplet 972 and the metal electrode 976, the droplet 972 maintains a shape defined by the volume of the droplet 972 and the contact angle θ1. The contact angle θ1 is determined by the interface tension, as described above.
As described above, since the dielectric insulating layer 974 is hydrophobic, the droplet 972 tends to be shaped spherical as a result of being "repelled" by the transparent substrate 974.
The shape of a droplet 978 represented by the dashed line shows the following state. As a result of a voltage V being applied between the metal electrode 976 and the droplet 972, an electronic wettability phenomenon occurs, and the hydrophobicity of the dielectric insulating layer 974 with respect to the droplet 972 is weakened (the hydrophilicity thereof is intensified); and therefore, the droplet 972 is uniformly diffused with respect to the dielectric insulating layer 974. The voltage V at this point is in the range of several volts to several hundred volts, and the polarity is irrelevant. By applying the voltage V between the metal electrode 976 and the droplet 972, the contact angle is decreased from θ1 to θ2. A diffusion amount determined by the difference between θ1 and θ2 is the function of the voltage V, and the contact angle θ2 is represented by expression 4.
                              cos                                                                          θ                                      (              V              )                                      =                              cos                                                                                θ                                            (                                  V                  =                  0                                )                                              +                                                                      ɛ                  0                                                                  ɛ                  γ                                                            2                                d                                                                                Y                                      L                    -                    V                                                                                V              2                                                          [                  Expression                                                              4                ]
In expression 4, θ (V=0) is the contact angle between the dielectric insulating layer 974 and the droplet 972 when no voltage is applied between the droplet 972 and the metal electrode 976. YL-V is the interface tension between the droplet 972 and air (or a gas or another fluid) enclosing the droplet 972. εγ is the dielectric constant of the insulating layer. ε0 is the permeability of vacuum, i.e., 8.85×10−12 F/m.
Utilizing such an electronic wettability phenomenon, a liquid microlens, the focal distance of which is reversibly changeable, can be formed.    Patent Document 1: Japanese Laid-Open Patent Publication No. 2001-142166    Patent Document 2: Japanese Laid-Open Patent Publication No. 2003-050303

Camera device, liquid lens, and image pickup method


The invention relates to a hearing aid for correcting hearing impairments, comprising a metal housing which has a battery compartment and a sound exit opening. According to the invention, the housing surrounds the electronics located in the treatment device in such a way as to shield them from electromagnetic waves on all sides and the sound exit opening is sealed by an acoustically permeable, water-tight film. The housing also has an essentially cylindrical shape.

The invention relates to an auditory treatment device for correcting hearing impairments.
German patent DE 38 40 393 C3 discloses such a treatment device which is worn in the ear. It has a pear-shaped or mushroom-shaped contour and contacts the auditory canal and external ear. The term "housing" is used to designate only the part contacting the skin of the wearer, which part actually belongs to a two-part housing, the outwardly visible front of the device being designed in the familiar fashion as a "cover plate" or "face plate" on which the entire electronics unit of the treatment device is located. These cover plates are composed of plastic which is normally designed to match the visual color of the ear since this cover plate is visible when the user wears it, whereas the metallic housing component extending into the ear is not visible.
The so-called "housing" is thus positioned simply like a hood on this cover plate and may be individually form-fitted to the individual patient. This "housing" may in fact be fabricated of metal to form an electrode which, interacting with a second electrode, forms an automatic on/off switch which automatically switches the device on when it is inserted into the ear and which also reduces the resistance between the electrodes due to skin moisture.
Due to the growing use of small, electronic devices used adjacent to the head, such as cellular or cordless telephones, generic treatment devices are often exposed to radiated noise, or may themselves generate radiated noise which interferes with such devices.
Due to the ever-smaller dimensions achievable for the electronics unit, and thus for the entire treatment devices for which miniaturization is desirable for cosmetic reasons, there exists the added risk of unintended damage to the treatment device when it is inadvertently ignored, or for example, loosens from or falls out of the wearer's ear during exercise.


With a view to improving the supporting stability for an X-ray detector, there is provided an X-ray imaging apparatus having an X-ray irradiating apparatus and an X-ray detecting apparatus opposed thereto, the X-ray detecting apparatus comprising an X-ray detector, a support mechanism which supports the X-ray detector through a hinge from a side opposite to an X-ray incidence plane, a shaft connected at one end portion thereof through a hinge to the X-ray detector on the side opposite to the X-ray incidence plane, and a linear actuator adapted to drive an opposite end portion of the shaft in a horizontal direction.

The present invention relates to an X-ray detecting apparatus and an X-ray imaging apparatus. Particularly, the present invention is concerned with an X-ray detecting apparatus having an X-ray detector whose direction can be changed, as well as an X-ray imaging apparatus having the X-ray detecting apparatus.
There is known an X-ray detecting apparatus having an X-ray detector whose direction can be changed. In this type of an X-ray detecting apparatus, the X-ray detector is made horizontal when the X-ray irradiating direction is vertical and the X-ray detector is made vertical when the X-ray irradiating direction is horizontal (see, for example, Patent Literature 1).
For supporting an X-ray detector in a cantilevered fashion and for making the direction of the X-ray detector changeable, there is used an X-ray detector supporting mechanism constructed for example as shown in FIG. 4. More specifically, an X-ray detector 100 is attached to a free end portion of a horizontal arm 300 through a hinge 301 and both ends of a linear actuator 500 are connected to the X-ray detector 100 and the arm 300 respectively through hinges 303 and 305. According to such a construction, the X-ray detector 100 can be brought into such a horizontal state as shown in FIG. 4(a) or such a vertical state as shown in FIG. 4(b) with extension or contraction of the linear actuator 500.
[Patent Literature 1] Japanese Published Unexamined Patent Application No. Hei 10(1998)-057360
In the X-ray detecting apparatus of the above construction, the linear actuator 500 is in its most extended state when the X-ray detector 100 is in its horizontal state. In such a state, the linear actuator 500 must bear the load imposed on the X-ray detector 100, but a triangle formed by the hinges 301, 303 and 305 is an obtuse triangle having a large vertex angle centered on the hinge 301, so that a force several times larger than the load on the X-ray detector 100 acts in the axial direction of the linear actuator 500 and hence the supporting stability for the X-ray detector 100 is deteriorated.

X-ray detecting apparatus and x-ray imaging apparatus

GE Medical Systems Global Technology Company, LLC