An indication of a host route to be added to a forwarding database table as an entry is received. The host route is added to a first hardware table or a second hardware table if a space is available in the second hardware table or in a first storage area of the first hardware table. The first hardware table has both a first storage area and a second storage area. If a space is not available in the second hardware table or the first storage area of the first hardware table, the first storage area of the first hardware table is automatically expanded to include unused space in the second storage area of the first hardware table. The host route is then added to a space in the expanded first storage area of the first hardware table.

Packet forwarding devices, such as layer 3 or IP routers, typically use one or more tables to store packet forwarding information. For example, layer 3 packet forwarding devices may include a hardware-implemented layer 3 host table that typically stores entries corresponding to hosts that are directly connected to the packet forwarding device. Each entry may include an IP address of a locally connected host and corresponding forwarding information for the locally connected host. When a packet arrives at the packet forwarding device, a lookup may be performed in the layer 3 host table based on the destination IP address in the packet. If a matching entry is located, the corresponding packet forwarding information is extracted from the layer 3 host table and used to forward the packet to the destination host. If an entry is not located, a miss occurs, and a slower lookup is performed using software.
Another type of table that may be maintained in a layer 3 packet forwarding device is a longest prefix matching (LPM) table. Each entry in a longest prefix matching table may include a subnet address and a subnet mask to be applied to destination IP addresses of incoming packets. When a packet is received, the subnet mask for each entry in the LPM table is applied to the destination IP address of the packet, and the masked address searched in the table. The entry with the longest prefix that matches the masked address in the received packet is used to extract next hop address information for the packet. Using an LPM table allows remote hosts to be identified by next hops without requiring entries in the LPM table for each individual remote host.
One problem with conventional packet forwarding devices is that space for the LPM and host tables is limited. For example, both tables are typically implemented in hardware to increase the number of hosts covered by hardware forwarding and therefore packet forwarding lookup speed. LPM tables are typically populated based on participation in routing protocols, such as routing information protocol (RIP), border gateway protocol (BGP) or open shortest path first (OSPF). When an LPM table becomes full, entries for remote hosts can be placed in the host table. However, the host table can also become full. When this occurs, packets received for destinations that are not present in the LPM or host tables must be forwarded using software, which results in longer lookup times.
In order to increase the routing efficiency of a layer 3 packet forwarding device, older entries in LPM and host tables may be replaced with newer entries. Conventionally, the replacement criteria for an entry include a least recently used (LRU) algorithm. That is, a host table entry that was used least recently may be replaced with a new entry for which a packet forwarding lookup fails. One problem with using an LRU algorithm to replace host table entries is that it is based on individual packets, which may result in excessive replacement of entries in the host table. For example, each time a miss occurs, an entry in the host table may be replaced. Such excessive replacement is undesired because replacing entries in the host table may be a processor intensive operation that requires a software copy of the host table be copied to hardware.
Another problem associated with using an LRU algorithm to replace entries in the host table is that such an algorithm does not take into account the volume of packets addressed to a destination. For example, an entry that was used 1000 times during a time interval more than one minute ago may be replaced by an entry that was used only once in the last minute. The high-volume entry may be more likely to be utilized in the future with a high volume than the low-volume entry. Thus, if the high-volume entry is replaced by the low-volume entry, multiple misses may occur before the high-volume entry can be re-added to the host table.
Accordingly, in light of these difficulties associated with conventional layer 3 packet forwarding devices, there exists a need for methods, systems, and computer program products for controlling updating of a layer 3 host table based on packet forwarding miss counts.
Again, packet forwarding devices, such as layer 3 or Internet protocol (IP) routers, typically use one or more tables to store packet forwarding information. Typically, packet forwarding devices include one or more hardware-implemented tables in addition to software-implemented tables in order to reduce packet forwarding information lookup time. For example, layer 3 packet forwarding devices may include a hardware-implemented host table populated with entries corresponding to individual hosts. When a packet arrives at a layer 3 packet forwarding device, a lookup may first be performed in the hardware host table. If the lookup is successful, the packet may be forwarded to a host corresponding to the matching entry in the table. If the lookup in the hardware host table fails to locate a match, a lookup may be performed in a longest prefix matching (LPM) table to locate the entry with the longest prefix that matches the address in the received packet. If the lookup in the LPM table fails to locate a longest prefix match, a software routing table may be searched in order to successfully forward the packet.
In some implementations, a hardware-implemented host table stores entries corresponding to hosts directly connected to the packet forwarding device. Each entry in the host table may include an IP address of a locally connected host and corresponding forwarding information. When a layer 3 packet arrives at the packet forwarding device, a lookup may be performed in the host table based on the destination IP address in the packet. This lookup is typically performed using a hashing function that identifies matching entries using a search key. If a matching entry is located, the corresponding packet forwarding information is extracted from the host table and used to forward the packet to the destination host. Host tables are typically searched before other tables because they store the most specific forwarding information for layer 3 packets.
A hardware-implemented LPM table stores subnet addresses and subnet masks to be applied to destination IP addresses of incoming packets. When a layer 3 packet is received, logical steps may be performed by a packet forwarding device where the subnet mask for each entry in the LPM table is applied to the destination IP address of the packet, and the masked address is searched in the table. In some implementations, these steps may be performed in a single LPM lookup using a special data structure, such as a Radix tree. The entry with the longest prefix that matches the masked address in the received packet is used to extract next hop address information for the packet. The next hop address typically corresponds to the next hop or machine in a path through which a remote host corresponding to the destination IP address in the packet is reachable. Using an LPM table allows remote hosts to be identified by next hops without requiring entries in the LPM table for each individual remote host. Thus, LPM tables may reduce a large number of hosts into fewer route entries by combining entries with the same next hop information. This allows an LPM table to store matching entries for more hosts than a host table of the same size.
Software lookups are performed by searching a much larger software table that stores layer 3 packet forwarding information. Lookups performed in software are significantly slower than lookups performed in hardware and therefore, it is desirable to perform as few lookups in software as possible.
As stated above, both host and LPM tables may be implemented or stored in hardware of a layer 3 packet forwarding device. In some implementations, the memory space available for both tables is shared. In order to increase the routing efficiency of conventional layer 3 packet forwarding devices, the relative sizes of the host and LPM tables are based on the expected number of communicating IP hosts. For example, edge devices that connect to a small number of hosts may utilize more memory for the host table and less for the LPM table. Devices, referred to as aggregators, that serve many communicating IP hosts may utilize more memory for the LPM table and less for the host table. Aggregators typically connect numerous smaller devices to a network infrastructure backbone or core network device and therefore route packets for a large number of hosts.
In edge devices, it may be desirable to route packets primarily using a host table, since the size of the host table would be small. In aggregators, it may be desirable to route packets primarily using an LPM table, since its entries represent plural hosts and populating a host table with all possible hosts would result in a table size that exceeds available memory space.
Layer 3 packet forwarding devices may have multiple modules, each containing host and LPM tables, for forwarding layer 3 packets. Conventionally, these modules are programmed identically and contain identical host and LPM tables as described above. However, as described above, it may be desirable to route some packets primarily using a host table and others primarily using an LPM table. Conventional IP packet forwarding devices do not provide for such varied operation.
Accordingly, there exists a need for improved methods, systems, and computer program products for routing layer 3 packets.

Method and system for automatic expansion and contraction of IP host forwarding database


Systems and methods for the manufacture of a magnetic head. A first embodiment provides an apparatus for the manufacture of a magnetic head comprising a feedback control loop to terminate lapping of the magnetic head responsive to achieving a target signal to noise ratio for the magnetic head.

Hard disk drives are used in almost all computer system operations. In fact, most computing systems are not operational without some type of hard disk drive to store the most basic computing information such as the boot operation, the operating system, the applications, and the like. In general, the hard disk drive is a device which may or may not be removable, but without which the computing system will generally not operate.
The basic hard disk drive model was established approximately 40 years ago and resembles a phonograph. That is, the hard drive model includes a plurality of storage disks or hard disks vertically aligned about a central core that spin at a standard rotational speed. A plurality of magnetic read/write transducer heads, for example, one head per surface of a disk, is mounted on the actuator arm. The actuator arm is utilized to reach out over the disk to or from a location on the disk where information is stored. The complete assembly, e.g., the arm and head, is known as a head gimbal assembly (HGA).
In operation, the plurality of hard disks is rotated at a set speed via a spindle motor assembly having a central drive hub. Additionally, there are channels or tracks evenly spaced at known intervals across the disks. When a request for a read of a specific portion or track is received, the hard disk drive aligns a head, via the arm, over the specific track location and the head reads the information from the disk. In the same manner, when a request for a write of a specific portion or track is received, the hard disk drive aligns a head, via the arm, over the specific track location and the head writes the information to the disk.
Over the years, refinements of the disk and the head have provided great reductions in the size of the hard disk drive. For example, the original hard disk drive had a disk diameter of 24 inches. Modern hard disk drives are generally much smaller and include disk diameters of less than 2.5 inches (micro drives are significantly smaller than that).
The recording or read/write heads of modern hard disk drives do not actually make contact with the recording media. Rather the heads "fly" on a cushion of air generated by the relative motion of the head over a rapidly spinning platter or disk comprising the recording media. The ability of a head to fly at a desirable height is a critical performance aspect of hard disk drives. Such flying heads are generally referred to or known as "sliders." As recording density increases, the slider flying height, e.g., the distance between a slider and a recording media surface, generally decreases. Such decreases in flying height typically require ever flatter slider surfaces. A lapping process typically determines a flatness characteristic of a slider.
A wafer is a basic "building block" upon which numerous processing actions take place to produce multiple components. Wafers also form a similar building block for the production of magnetic read and/or write heads ("sliders") as used in hard disk drives. The production of such devices can comprise many different processing steps. It is not uncommon for hundreds of operations to be performed on wafers to produce magnetic heads.
In recording head technology, the volume or size of the recording sensor is very small. For example, modern recording sensors are of the order of 100 nm. Typically, such sensors become ever smaller with successive generations of hard drive technology. In general, such heads are so small that each sensor has unique signal and noise characteristics due to individual microstructure, milling and lapping surface conditions. For example, removing a few nanometers of material from a reading sensor during a lapping process can dramatically affect various operational characteristics of a head, e.g., resistance, signal amplitude and/or signal to noise ratio.
In a conventional head manufacturing process, a head or set of heads is lapped to establish surface quality and a target sensor stripe height. Unfortunately, lapping to a well controlled target stripe height produces an undesirably broad distribution of amplitude and drive performance results from such conventional head manufacturing processes.
Accordingly, there is a need for systems and methods for manufacturing magnetic heads. Additionally, in conjunction with the aforementioned need, systems and methods for manufacturing magnetic heads that account for unique signal and noise characteristics of individual magnetic heads are desired. A further need, in conjunction with the aforementioned needs, is for manufacturing magnetic heads in a manner that is compatible and complimentary with existing magnetic head processing systems and manufacturing processes.

System and method for manufacturing magnetic heads

Hitachi Global Storage Technologies Netherlands B.V.


Real-time multimedia services are transmitted over a hybrid network including a nonguaranteed quality of service packet switched local area network and a circuit switched ISDN wide area network having a centralized multimedia bridge located within the wide area network. The local area networks and multimedia bridge are interconnected via ISDN routers. An algorithm executed by the multimedia bridge receives signals from the packet switched network and detects the absence of properties needed for real-time audio visual services. The data signals are processed to compensate for the absence of the properties and then are transmitted over the wide area network to enable real-time audio visual services.

Real-time multimedia services have been provided in the past by connecting signals over circuit switched networks having guaranteed quality of service. Although this approach results in reasonable quality, it is cost prohibitive for many potential users. Most offices desiring multimedia services, such as video conferencing, are served by a packet switched local area network (LAN) providing nonguaranteed quality of service. Such networks are inherently unreliable for multimedia. The multimedia packet streams coming from such networks do not have the proper sequencing. The arrival time between the packets may have significant variations known as delay jitter, and some packets may be lost. Moreover, the recovered bit streams of audio and video do not maintain required temporal relationships to insure both intramedia and intermedia synchronization so the lip-synchronization is maintained. Since the cost of installing a guaranteed quality of service network in such offices is prohibitive, the adoption of multimedia services in most offices has been severely restricted.
One attempt to provide video and audio services is described in U.S. Pat. No. 4,866,704 (Bergman, filed Mar. 16, 1988). Bergman describes the conversion of data to T1 frames and then an additional conversion to packets for distribution on a wide band fiber optic ring. This arrangement is contrary to the existing local area network structure found in most offices, and therefore would required the installation of new networks at prohibitive expense.
Another approach to transmitting data from one location having a local area network to a second location having a local area network via a T1 network is described in U.S. Pat. No. 5,384,835 (Wheeler et al., filed Jan. 12, 1993). Wheeler et al. teach such a network arrangement for distributing text data and still graphic data. However, they do not describe any method or apparatus for providing real time video and audio over the local area and T1 networks.

Packet mode multimedia conferencing services over an ISDN wide area network


A process for removing sulfur compounds from a liquid hydrocarbon stream includes the steps of feeding the hydrocarbon stream to a recirculation section of an extraction vessel wherein the recirculation section contains a first alkaline solution; passing the hydrocarbon stream through the recirculation section; recirculating at least a part of a first alkaline stream to a top deck of one or more liquid-liquid contacting decks of the recirculation section; passing the hydrocarbon stream from the recirculation section to an extraction section of the extraction vessel wherein the extraction section includes one or more liquid-liquid contacting decks; feeding a second alkaline stream to an upper deck of the one or more liquid-liquid contacting decks of the extraction section wherein the second alkaline stream includes a second alkaline solution; and withdrawing a hydrocarbon product stream from the extraction vessel. An apparatus for removing sulfur compounds from the hydrocarbon stream is also disclosed.

1. Field of the Invention
This invention relates generally to a process and apparatus for the removal of organic sulfur compounds from a stream containing hydrocarbons. In particular, it relates to the use of an aqueous caustic solution to remove mercaptans from a hydrocarbon stream.
2. Description of the Related Art
It is conventional practice at the present time to treat sour gas and liquid hydrocarbon streams to remove mercaptans. Extraction processes are typically used when treating light liquid hydrocarbons and gas streams for mercaptan removal. Mercaptans have traditionally been removed from hydrocarbon streams because of their malodorous scent.
U.S. Pat. No. 5,244,643 discloses a process whereby a hydrocarbonaceous gas stream including mercaptan sulfur, air and aqueous alkaline solution including a mercaptan oxidation catalyst are mixed in a mixing vessel in which mercaptans are converted to disulfides. The effluent withdrawn from the top of the mixing vessel is settled in a vessel to yield separated streams of air, liquid hydrocarbon product containing disulfide, and an aqueous alkaline solution including mercaptan oxidation catalyst.
U.S. Pat. No. 4,562,300 discloses contacting a hydrocarbon stream including organic mercaptans with sodium hydroxide to free the hydrocarbons from the organic mercaptans. The caustic solution rich in mercaptans is oxidized with a catalyst and the organic mercaptans are converted to organic disulfides. The mixture of regenerated caustic solution free of organic mercaptans and organic disulfides enter a settler in which the organic disulfides and caustic solution are separated. A stream of hydrocarbon from which the mercaptans had been extracted upstream are admixed with regenerated aqueous caustic solution containing small amounts of organic disulfides to extract the organic disulfides from the regenerated caustic solution.
In a typical liquid-liquid extraction process, a liquid hydrocarbon stream is fed to an amine absorber column to be contacted with an amine, such as diethylamine, to absorb acid gases such as hydrogen sulfide and carbon dioxide from the hydrocarbon stream. The hydrocarbon stream lean of hydrogen sulfide and other acid gases is prewashed in a prewash vessel containing 6.5 to 15.0 wt. % liquid caustic to convert the remaining hydrogen sulfide to sodium sulfide which is soluble in caustic. The hydrocarbon stream, now depleted of hydrogen sulfide, is subjected to counter-current flow of a liquid caustic in an extraction vessel. Jet decks in the extraction vessel facilitate the counter-current contact. Mercaptans in the hydrocarbon stream react with the caustic to yield mercaptides. The mercaptides in the hydrocarbon stream are soluble in the caustic. A product hydrocarbon stream lean in mercaptans passes overhead from the extraction column through a settler drum to a sand filter vessel, and the mercaptide rich caustic passes from the bottom of the column. The settler drum allows for settling and buffers the sand filter against caustic surges. The sand filter coalesces caustic to make it gravitate to the bottom of the vessel while the product hydrocarbon stream passes out of the vessel through an outlet that is shielded at the top to prevent admittance of falling caustic droplets. The mercaptide rich caustic receives an injection of air and catalyst as it passes from the extraction column to an oxidation vessel for regeneration. Oxidizing the mercaptides to disulfides using a phthalocyanine catalyst regenerates the caustic solution. A disulfide separator receives the disulfide rich caustic from the oxidation vessel. The disulfide separator vents excess air and decants disulfides from the caustic before the regenerated caustic is drained and returned to the extraction vessel. The disulfides are run through a sand filter and removed from the process.
One conventional mercaptan extraction system utilizes four vessels: the caustic prewash vessel, the extraction vessel, the settler drum, and the sand filter vessel. Each vessel must have its own support and base structure making building this system capital-intensive. U.S. Pat. No. 6,749,741 discloses combining the extraction vessel, the settler drum, and the sand filter vessel into one vessel to thereby reduce the capital required to build an extraction system. In the combined vessel, a caustic solution enters the extractor section of the vessel and passes through this portion of the vessel in order to remove mercaptans from a hydrocarbon stream resulting in spent caustic rich in mercaptides. The spent caustic is then recovered from the extractor section of the vessel and regenerated in a downstream process. The regenerated caustic can then be recycled back to the extractor section of the vessel. Furthermore, spent caustic in the prewash section of the vessel that is rich in sulfide salts can be recovered. Part of the recovered caustic is recycled back to the prewash section of the vessel while the remainder is removed from the process.
In the above described mercaptan extraction system, the caustic is regenerated to allow reuse in the extraction vessel, thus limiting the amount of caustic needed. However, the need for a caustic regeneration necessitates additional capital to build a regeneration system.
Accordingly, what is needed is a "once-through" type extraction vessel, where the caustic is only used once before being sent to effluent treatment to thereby further reduce the capital required to build an extraction system. Also, there is a need for a "once-through" type extraction vessel which minimizes the amount of fresh and spent caustic that is needed.

Apparatus and process for removal of sulfur-containing compounds from a hydrocarbon stream


A radar system operates at various different frequencies, and routes power among various antennas by use of a hybrid arrangement. The system is precalibrated at each possible operating frequency by adjusting the phase shifts associated with the hybrid in a feedback manner to provide optimal performance, and the calibration values are stored. During normal operation, the calibration values of phase shift are selected and used for feedforward operation at each frequency.

Modern transmitter systems, such as television and radar systems, require generation and phase control of high power signals. In order to obtain sufficient power, multiple high-power signal sources are often combined by the use of hybrid combiners. Those skilled in the art know that hybrid combiners may also be used to split applied signals, and are not limited to combining.
In a radar context, the signals applied to a transmitting antenna must be steered, which requires phase control of the signals applied to each element of the antenna array. In some radar systems, the signals must be applied or "switched" to separate antenna arrays facing in different directions for transmission of electromagnetic signals in the selected directions. In the context of high-power signals such as radar pulses, the switching may be conveniently accomplished by control of the phase of signals applied to the various input ports of a hybrid combiner. Proper switching of signal by the use of a hybrid combiner requires that the phase relationship of the applied signals be closely controlled, as otherwise signals may "leak" away from the desired port to other, non-selected ports.
In the context of a radar system in which the transmission frequencies change from time to time, the frequency changes may result in undesired phase conditions at the hybrid ports, especially at the edges of a frequency band or range. These undesired phase conditions, in turn, may result in leakage of the signal away from the desired ports at some frequencies within a frequency band.
Improved or alternative phase control arrangements and/or methods are desired.

Optimization of radar antenna switching hybrid in response to operating frequency


Apparatus and method of combusting crude oil produced during testing of a subterranean well includes a primary nozzle for atomizing and spraying the primary feed of crude oil into a combustion chamber; a combustion chamber for receiving and combusting the atomized primary feed and confining the combustion so that the primary feed is completely combusted in the combustion chamber; and an ignitor for igniting the combustion. A secondary nozzle may be located in the combustion chamber for atomizing and spraying a secondary feed of crude oil into the combustion chamber so that the heat of combustion of the primary feed will vaporize the secondary feed and heat the secondary feed above its ignition temperature so that it will completely combust on contact with air. A heat exchanger may be provided which uses the heat from the combustion chamber for preheating the crude oil before the crude oil is supplied to the primary or secondary nozzle.

This invention relates to apparatus and method for combusting crude oil and, more particularly, relates to apparatus and method for combusting crude oil during oil well production tests.
The development and improvement of apparatus and methods for abating any pollution created during oil and gas exploration and production are a high priority for the industry. One source of such pollution is the hydrocarbon fluids produced during the well production tests which are conducted to provide an estimate of the maximum flow and composition of the fluids to be produced from a well. There are a number of uncertainties which create pollution-related problems during production tests. For example, some of the production tests are conducted after the well is drilled and before facilities are built to handle the produced fluids, since one purpose of the tests is to determine the type and capacity of equipment needed to process the produced fluids so that the fluids may be transported or stored. Once a production test is started, it must be allowed to continue for a known period of time to accurately predict the production capacity of a well; and, therefore, the disposal system must be able to accommodate the unknown, widely-fluctuating flow rates and unknown composition of the produced fluids. The oil produced during a well test often contains gas, contaminants, and particulate matter and is therefore difficult to store, transport, or burn, particularly on offshore platforms and in remote locations.
Because of these uncertainties, the current practice of the industry is to burn the produced fluids (hereinafter referred to as "crude oil"). To the best of applicant's knowledge, the crude oil produced during well tests has always been burned using open-air burners, i.e., flares in which the burner and flame are exposed to the open air. For examples see U.S. Pat. Nos. 3,565,562; 3,632,287; 3,797,992; 3,807,932; 3,914,094; 3,948,196; 3,980,416; 4,348,171; 4,412,811; and 4,452,583. These open-air burners are difficult to control and often produce large volumes of black smoke, volatile organic compounds, unburned hydrocarbons, carbon monoxide, nitrogen oxides, and unburned oil which is deposited on the land or water around the burner. This is attested to by some of the prior patents which disclose apparatus for reducing the smoke created during open-air burning.
Despite prior attempts to provide an environmentally acceptable open-air burner, none have proven entirely satisfactory. The present invention provides method and apparatus for burning the crude oil, as well as other hydrocarbon products, produced during a well test in a pollution abating, environmentally acceptable manner by enclosing a burner or nozzle and controlling the combustion of the crude oil so that a virtually pollution-free combustion is achieved. Although burners for commercial quality oil which enclose the flame are known, such as those disclosed in U.S. Pat. No. 2,701,608 and U.S. Pat. No. 3,603,711; as are burners for contaminated oil which partially enclose the flame to reduce noise levels during burning, as disclosed in U.S. Pat. No. 4,155,702; in the applicant's knowledge no attempt has been made to totally enclose the combustion of crude oil produced during well testing. Further, no attempt has been made to use the heat of combustion of the crude oil to enhance the combustion and produce a pollution abating combustion. It is contemplated that the wide range of flow rates and the unpredictable qualities of the crude oil encountered during well testing, as well as the extreme temperatures and the concern with keeping the size and cost of the disposal facilities at a minimum, have taught away from enclosing the combustion of crude oil produced during well tests.

Apparatus and method for combusting crude oil


When the distal end of a radiation detection probe (2) is directed toward a place to be measured, pointer light emitted by a light-emitting device (7) sequentially passes through a transmission window (5C) of a radiation detection element (5) and a projection window (3E) of a probe cover (3) to be emitted onto the place to be measured. This pointer light clearly indicates the place as a bright spot. The radiation from the place passes through the distal end of the probe cover (3) to be collimated by a radiation-introducing window (4A) of a side shield (4), and then enters the radiation detection element (5). The dose of the radiation is detected in this way.

A handheld medical radiation detector is disclosed in U.S. Pat. No. 6,236,880 B1. This radiation detector has a probe and a probe detachably mounted to the distal end of the probe.
Common radiation detectors with a radiation detection probe are designed to bring the tip of the probe into contact with a place to be measured or as close as possible to the place in order to detect the radiation. Therefore, when the tip of the probe is far from the place from which the radiation is being detected, it is difficult for the user to locate the place.


A manufacturing method of an ultrasonic generating device includes applying a compressive force to an attachment unit toward a first axial direction while a first end of a bolt-shaped member is a free end and the second end thereof is fixed, and thereby generating a first elastic force in the attachment unit. The manufacturing method includes attaching a fastening member to a bar portion of the bolt-shaped member in a balanced condition in which a second elastic force of the bolt-shaped member and the first elastic force are in balance, and thereby maintaining the balanced condition.

1. Field of the Invention
The present invention relates to a manufacturing method of an ultrasonic generating device which configured to generate an ultrasonic vibration when supplied with a current, and an assembling system of the ultrasonic generating device.
2. Description of the Related Art
Jpn. Pat. Appln. KOKAI Publication No. 64-36200 has disclosed an ultrasonic generating device which is configured to generate an ultrasonic vibration when supplied with a current. This ultrasonic generating device includes a bolt which includes a head portion, and a bar portion smaller in an outside diameter than the head portion. An attachment unit which includes piezoelectric elements configured to convert the current to the ultrasonic vibration is attached to the bar portion of the bolt. The attachment unit is fastened between the head portion of the bolt and a nut which is a fastening member, and is contracted. The piezoelectric element is contracted by the contraction of the attachment unit, and the conversion from the current to the ultrasonic vibration is properly performed by the piezoelectric elements.
In the manufacture of the ultrasonic generating device having the configuration described above, it is necessary to contract the attachment unit which includes the piezoelectric elements. In a general manufacturing method, the attachment unit is fastened by the nut to apply a compressive force to the attachment unit (piezoelectric elements) from the nut and contract the attachment unit. In the manufacturing method according to Jpn. Pat. Appln. KOKAI Publication No. 64-36200, a compressive force is applied to the attachment unit (piezoelectric elements) by a force applying unit separate from the nut to contract the attachment unit. When the attachment unit is contracted to a predetermined contraction state, the nut is attached to the bar portion of the bolt, and the attachment unit is fastened between the head portion of the bolt and the nut. As a result, the predetermined contraction state of the attachment unit is maintained. Here, when the compressive force is applied to the attachment unit from the force applying unit, both ends of the bolt are fixed in directions parallel to a longitudinal axis, and are fixed ends.

Manufacturing method and system for an ultrasonic generating device that includes an attachment unit to generate an ultrasonic vibration


The present invention provides an image correction method and a related image correction system which can correct images captured via a fisheye lens or a ultra-wide angle lens camera so as to alleviate geometrical distortion in the images, and geometrically adjust the images according to user's requirements. Wherein, the present invention further enhances the processing performance of image correction computation by a memory allocation technique.

1. Field of the Invention
The present invention relates to image processing, and more particularly, to an image processing method for correcting geometrical distortion caused by fisheye lens or ultra-wide angle lens and related image processing system.
2. Description of the Prior Art
Fisheye lens and ultra-wide angle lens are widely used in monitor cameras or general digital cameras. Though this type of camera may capture a scene that is in a quite large angle of view, the captured image is often accompanied with severe geometrical distortion, which will make a user unable to recognize some details in the captured image easily and clearly. In a worst case, the user may fail to recognize the image details due to the geometrical distortion. Therefore, images generated by fisheye lens and ultra-wide angle lens should be restored to images conforming to the original scenes for user's viewing by being processed by proper image processing techniques.

Image correction method and related image correction system thereof


There is provided a liquid lens in which a voltage is applied to control the shape of the interface between a polar liquid and a nonpolar liquid so as to control a transmitted light path at the interface. The liquid lens has a cavity with a polygonal upper side, into which the polar liquid and the nonpolar liquid are injected to form the interface.

The present disclosure relates to a liquid lens and particularly to a liquid lens with improved transmittance and light collection efficiency.
There are variable-focus liquid lenses of related art that use change in interface between two liquids whose wettability is changed by voltage application so as to change the focal length. For such variable-focus liquid lenses of related art, there has been proposed a method for forming a cavity to center the liquids, as shown in FIG. 1A (see JP-T-2002-540464, for example).
As shown in FIG. 1A, a liquid lens 1 includes ribs 13 and 14, lower electrodes 15 and 16, an insulating film 17, a nonpolar liquid 18, a polar liquid 19, and upper electrodes 20 and 21 in the space between a transparent substrate 11 and a transparent top plate 12. The upper electrodes 20, 21 and the lower electrodes 15, 16 of the liquid lens 1 are connected via a power supply 31 and a switch 32. That is, when the switch 32 is turned on, a voltage from the power supply 31 is applied between the upper electrodes 20, 21 and the lower electrodes 15, 16. This voltage application changes the wettability of the nonpolar liquid 19, so that the shape of the interface between the nonpolar liquid 18 and the polar liquid 19 is changed and shaped into a curved convex lens. This shape of the interface focuses light that passes through the two-liquid layer. The curvature of the interface between the two liquids can be adjusted by adjusting the value of the applied voltage, allowing the focal length of the liquid lens 1 to be changed.
JP-T-2002-540464 describes how to center the liquids by forming and using a center-axis symmetric truncated cone-shaped cavity or an elongated groove-shaped cavity. That is, as shown in FIG. 1B, a circular cavity 41 is formed when the liquid lens 1 shown in FIG. 1A is viewed from the transparent top plate 12 side.
There has been also proposed a method for arranging such variable-focus liquid lenses of the related art in an array for use, as shown in FIG. 1C (see JP-A-2000-356708, for example).
For example, liquid lenses 1, each having a cavity 41 with a circular upper side, as described in JP-T-2002-540464 are arranged in an array as described in JP-A-2000-356708, so as to form a liquid lens array 51 as shown in FIG. 1C.
When light enters the liquid lens array 51, part of the light enters the portion indicated by the dotted line 52, passes through the liquid lenses 1-1 to 1-3, and is focused as indicated by the arrows shown in FIG. 2A.
However, among the light incident on the liquid lens array 51, the light incident on the portion indicated by the dotted line 53 does not pass through the cavities 41 of the liquid lenses 1-4 to 1-6, but is blocked as indicated by the arrows shown in FIG. 2B. Therefore, light transmittance of the entire liquid lens array 51 could be reduced.
Even when the portion other than the cavity 41 of each of the liquid lenses 1 is made of a material transparent to light, among the light incident on the liquid lens array 51, the light incident on the portion indicated by the dotted line 53 does not pass through the cavities 41 of the liquid lenses 1-4 to 1-6, so that it is not focused as indicated by the arrows shown in FIG. 2C. Therefore, the light collection efficiency of the entire liquid lens array 51 could be reduced.


A torque transmission device includes an input shaft, an output shaft, a helical spring, a fixing member, and a stopping member. The helical spring has an input portion frictionally connected to the input shaft and an output portion frictionally connected to the output shaft, and rotatable together with the input shaft and the output shaft to transmit the torque of the input shaft to the output shaft. The stopping member is engageable with an input end portion of the spring at a predetermined engaging position and adapted for stopping the output shaft at a predetermined rotational position. The fixing member is used to fix an output end portion of the spring on the output shaft at such a position as to assure a predetermined phase relationship between the engaging position and the rotational position.

This invention relates to a torque transmission device capable of intermittently switching torque transmission between an input rotary member and an output rotary member to rotate and stop the output rotary member at a specified rotational position.
In copying machines in which document images are copied on copy sheets, it has been known to be necessary to feed sheets intermittently at specified intervals when a variety of processings are applied to the sheets being transported. Feed rollers have been generally used to feed the sheets intermittently. A pair of feed rollers are arranged opposed to each other. Sheets inserted manually or transported by another feeding means from an upstream side are introduced to a nip between the roller pair and are fed to a downstream side one by one, and a desired processing is applied to the sheets at the downstream side. In this case, in order to feed the sheets by means of the feed rollers reliably, the feed rollers are caused to stop at specified rotational positions, and the sheet is inserted into the nip between the pair of feed rollers while rotation of the feed rollers is suspended. After the sheet is completely inserted into the nip, the feed rollers are drivingly rotated by means of a manual operation or upon automatically detecting the insertion of the sheet, so that the sheet can be fed to the downstream side reliably. Since the feed rollers are rotated and stopped at the specified positions alternately in this way, there is normally employed a spring clutch structure for transmitting on and off a torque to a rotary shaft of the feed rollers.
FIGS. 6A and 6B show a construction of an exemplary spring clutch. FIG. 6A is an exploded front view showing a mounting relationship of basic components of the spring clutch including a helical spring 100, a coupler 120 fixedly attached to an input shaft (driving side), a coupler 110 fixedly attached to an output shaft (feed roller side), and a collar 130. FIG. 6B is a side view of the coupler 110 when viewed from the right side.
The helical spring 100 has a specified inside diameter in a free state (i.e. in a state where no force is acting on the helical spring 100), and has an output end portion 101 and an input end portion 102 bent in axial directions thereof so as to serve as engaging portions respectively. Normally, the helical spring 100 is fabricated such that the phase of the output end portion 101 coincides with that of the input end portion 102 before they are placed on respective outer circumferential surfaces of the couplers 110 and 120. The couplers 110, 120 are designed such that the outside diameters thereof are at least slightly larger than the inside diameter of the helical spring 100. The helical spring 100 has one side portion thereof pressingly fitted on an outer circumferential surface of the coupler 110 and has the other side portion pressingly fitted on an outer circumferential surface of the coupler 120. On an output end of the coupler 110 and an input end of the collar 130 are provided flanges having a large diameter. The collar 130 is rotatable on the coupler 120. In the flange of the coupler 110 is formed a groove 111 in which the output end portion 101 of the helical spring 100 is fitted. Likewise, in the flange of the collar 130 is formed a hole (or groove) 131 in which the input end portion 102 of the helical spring 100 is fitted. By fitting the output and input end portions 101. 102 in the groove 111 and the hole 131 respectively, the collar 130 and the helical spring 100 are prevented from idly rotating. The coupler 110 is formed with a D-shaped hollow having a fitting surface 112 as shown in FIG. 6B. To the fitting surface 112 is fitted an unillustrated rotary shaft of the feed roller (a mating portion of the rotary shaft has at least a similar D-shaped cross-section), thus enabling the coupler 110 and the unillustrated rotary shaft of the feed roller to rotate integrally. Indicated at 132 is a projection formed at a specified position on the flange of the collar 130. When the projection 132 is in a specified rotational position, the spring clutch is caused to be disengaged. More specifically, the projection 132 comes into contact with an unillustrated stopping member, and a force acts in a direction opposite to a winding direction of the helical spring 100. As a result, the helical spring 100 is loosened radially and only the coupler 120 rotates with sliding on the inside surface of the spring 100. Consequently, the clutch is disengaged and the transmission of the torque from the coupler 120 to the coupler 110 is interrupted. In this way, the feed roller is controllably caused to rotate and stop at the specified rotational position.
As described above, the feed roller can be stopped at the specified rotational position when an angular position of the collar 130 whose rotation is regulated by the combination of the projection 132 and the stopping member is held in specific corresponding relation to the phase of the feed roller mounted on the rotary shaft fitted to the fitting surface 112 of the coupler 110. Thereby, the sheets can be inserted into the nip between the stationary feed roller pairs reliably.
The phase relationship between the input end portion 102 of the helical spring 100 and the fitting surface 112 of the coupler 110 is determined by the phase relationship between the input end portion 102 and output end portion 101 of the helical spring 100. However, the phase relationship between both end portions 101, 102 is not in a fixed relationship and is liable to change with springs and couplers. Accordingly, the phase relationship between the input end portion 102 and the fitting surface 112 is not fixed. Consequently, it is difficult to control stopping of the rotary shaft fitted on the coupler 110 at a specified rotational position.
More specifically, the output and input end portions 101, 102 of the helical spring 100 have a specific phase relationship (for example, they are in the same phase in FIG. 6A) until the helical spring 100 is mounted on the couplers 110 and 120. However, since the outside diameters of the couplers 110, 120 are set slightly larger than the inside diameter of the helical spring 100, the diameter of the helical spring 100 is increased when the helical spring 100 is mounted on the couplers 110 and 120. Accordingly, the phase relationship between the output and input end portions 101, 102 changes with changes in the fitting or mating lengths of the helical spring 100 and the couplers 110 and 120. In FIG. 6A, for example, when the input end portion 102 is fitted in the hole 131, the collar 130 rotates, and the projection 132 consequently shifts. It should be noted that production of couplers and springs involve dimensional variations for various reasons. Accordingly, the phase relationship between the input end portion 102 and the output end portion 101 differs in individual products due to the dimensional variations. Thus, it will be impossible to assure a fixed phase relationship between the input end portion 102 and the fitting surface 112 of the coupler 110, and to then stop the output shaft or the feed roller at a specified rotational position.


An information signal reproducing apparatus for reproducing information signals from a recording medium on which several parallel tracks are formed, in which a tracking error signal is produced by use of signals reproduced by a head means for tracing the recording medium so as to reproduce signals, and the tracking error signal is sampled with periods which are determined, irrespective of a rotational period of a rotary head, so as to provide a tracking control signal. Further, upon reproduction of information signals from the recording medium on which plural kinds of pilot signal components are recorded at several parallel tracks together with the information signals, a first tracking error signal which is produced in accordance with the pilot signal components among signals reproduced by one of a plurality of heads for tracing the recording medium so as to reproduce signals, and a second tracking error signal which is produced by in accordance with the pilot signal components among signals reproduced by another of the plurality of heads, are selectively used.

1. Field of the Invention
The present invention relates to an information signal recording apparatus and an information signal reproducing apparatus for several tracks in parallel with one another formed on a recording medium, and in particular to those having features in tracking control for the tracks. For example, the tracking control is used in an apparatus such as a VTR having rotary heads through which video-signals from oblique tracks recorded and formed on a magnetic tape are reproduced.
2. Related Background Art
Heretofore, as a reproducing tracking system for home VTRs, a system (CTL system) in which a stationary magnetic head is provided in a part of a tape path so as to record vertical synchronization signals separated from recording signals upon recording, on an exclusive control track formed longitudinally of a tape, and a system (4fATF system) in which four kinds of pilot signals having relatively low frequencies are circulately recorded on a track, being superposed with main signals such as video signals and audio signals recorded on the same track, by a rotary head for recording and reproducing the main signals, so that cross-talk components reproduced from two adjacent reproducing tracks are compared with each other upon reproduction in order to obtain tracking error signals (ATF signals), have been proposed and put into practice.
However, the above-mentioned CTL system requires a space for the stationary head, and accordingly this system is unadvantageous in view of miniaturization. On the contrary, the 4fATF system is advantageous in view of miniaturization, but is disadvantageous since it requires a complicated circuit arrangement for the four kinds of pilot signals which require several analog circuit elements, and since the pilot signals superposed with digital signals occupy a relative wide band width so as to lower the reliability of the digital signals.
Meanwhile, recently, even for home VTRs, VTRs such as that picture signals in one field are divided and recorded on a plurality of tracks in order to record and reproduce a relatively large volume of information so as to cope with a high image quality and digitalization, have been developed, and accordingly, new tracking systems suitably used for these home VTRs have come under consideration. That is, one of these new tracking systems is such that recording signals are recorded so that frequency components corresponding to a specific kind of pilot signals are contained in modulated signals when digital signals to be recorded is modulated, and the tracking control pilot signals are superposed with the digital signals in a multiplex manner through the above-mentioned modulation.
Referring to FIG. 1A which is a plan view showing a drum of a VTR, a rotary drum 40 comprises a tape 41, a ch-1 head 42 of +azimuth, a ch-2 head 43 of -azimuth, a ch-3 head 44 of +azimuth, and a ch-4 head of -azimuth.
Referring to FIG. 1B which is a front view showing heads that can be seen upon rotation of the drum, for explaining the attachment heights of the heads 42, 45, the ch-1 and ch-2 heads, and ch-3 and ch-4 heads are, in pairs, arranged so as to be adjacent to each other. These pairs are arranged at intervals of an angle of 180 deg. so as to be opposed to each other. As is clear from this figure, the ch-2 and ch-4 heads are offset by a distance h which corresponds to one track pitch on the tape, with respect to the ch-1 and ch-3 heads. With this arrangement, two tracks can be simultaneously recorded or reproduced for every half rotation of the drum, that is, it can cope with a large volume of information.
Next, explanation will be made of the new tracking system with reference to FIG. 2 which is a view illustrating a recording pattern on the tape 41. In order to obtain a tracking error signal, two kinds of pilot signals having frequencies f1, f2 are used, and are superposed with main signals every other track. The rotation of generation of the pilot signals are such that one turn is made through four tracks, and no superposition of the pilot signals occurs on tracks belonging to the heads of +azimuth but pilot signals having f1, f2 are alternately superposed on tracks belonging to the heads of -azimuth. It is noted that reference numerals (1) to (10) denote frame numbers in each of the tracks, that is, signals in one frame are divided and recorded on ten tracks.
As mentioned above, in this example, since four tracks are recorded and reproduced per rotation of the drum, 2.5 turns are required for scanning tracks in one frame, and the pilot rotation and the frame are synchronized with each other by units of two frames (20 tracks).
FIG. 3 is a timing chart showing pilot signals which are superposed with main signals by the heads (ch-1 to ch-4), and the pilot signals which are reproduced from the heads. Explanation will be hereinbelow made with reference to this figure.
In FIG. 3, there are shown a frame signal (a) upon recording or reproduction, a head switch signal (b), pilot timing (c) which is recorded by the ch-1 and ch-3 heads, and which is shown so that it is not superposed, pilot timing (d) which is recorded by the ch-2 and ch-3 heads, which is shown so that pilot signals f1, f2 are alternately recorded, pilot signals (e) which are reproduced by the ch-1 and ch-3 heads in a satisfactory reproducing condition, and reproducing timing (f) of pilot signal components which are similarly reproduced by the ch-2 and ch-3 heads.
As understood from FIG. 2, by setting the head width of each of the heads to be wider than the track pitches, pilot signals recorded on two adjacent tracks can be reproduced in the form of crosstalk at the reproducing timing by the ch-1 and ch-3 heads, and accordingly, this system can provide a tracking error signal (ATF) with the use of such a fact that crosstalk components are equal to each other between the two adjacent tracks if the tracking condition is satisfactory.
FIG. 4 is a block diagram illustrating a circuit for detecting the above-mentioned ATF error signal during reproduction.
Referring to FIG. 4, a head switch signal (HSW) 70 changes over between the reproduced signals from the ch-1 and ch-3 heads in synchronization with the rotation of the drum, a switch circuit 79 changes over between reproduced signals from the ch-1 and ch-3 heads in response to the HSW signal 70, a band-pass filter (BPF) 71 extracts only the reproduced pilot signals f1, f2 from reproduction RF signals, and an amplifier 72 amplifies the reproduced pilot signals which are outputs from the BPF 71. Further, a band pass filter (BPF) 73 extracts only the component f2 from the output of the amplifier 72, a band pass filter (BPF) 74 extracts only the component f1 from the output of the amplifier 72, a detecting circuit for converting the component f2 which is the output of the BPF 73, into a d.c. level, a detecting circuit 76 similarly converts the component f1 into a d.c. level, a differential amplifier circuit 77 receives both detected outputs, and an invertor circuit 78 inverts the signals, and a switch circuit 80 changes over between the output of the differential amplifier 77 and the output of the invertor circuit 78 in response to the HSW 70. A process circuit 81 for reproduced signals in the video-audio system processes the reproduced RF signals so as to provide reproduced video-signals and reproduced audio signals.
Next, explanation will be made of operation. As mentioned above, in the system in this example, the reproduced pilot signals for providing the ATF error signal are included, as crosstalk components from two adjacent tracks (-azimuth track), in the reproduced signals by the ch-1 and ch-3 heads of +azimuth. Accordingly, only the reproduced signals from the ch-1 and ch-3 heads, among the four heads, are required, and the reproduced pilot signals are turned into reproduced signals for only a single system by means of the switch circuit 79. The reproduced signals which contain the main signals are naturally led to the video-audio system reproduction processing circuit 81, and are also applied to the BPF 71 as an ATF circuit for extracting the reproduced pilot signals. Thereafter, the crosstalk components f1, f2 are separated and detected, and are compared by the differential amplifier 77 so as to obtain the ATF error signal for a single system.
Thereafter, the switch circuit 80 selects the invertor circuit 78 upon selection of the ch-3 head, being synchronized with the HSW 70 so as to cope with fore-and-aft positional exchanges of the tracks for the components f1, f2 by the ch-1 and ch-3 heads.
The new tracking system has been hereinabove explained, which will be hereinbelow denoted as "2fATF" as necessary.
Further, as to conventional high speed reproduction such as high speed search of a VTR which carries out analog recording, since the reproduced picture directly corresponds to a position where the reproducing head traces a track, it is common to control the position of the head trace so as to fix a noise bar on an image plane. For this purpose, the magnification of the travel speed of a tape is set to be N (where N is an integer equal to or larger than 2), that is, the travel speed is set to be N times as high as that during reproduction, and a tracking error signal is sample-held in synchronization with the rotation of the head so as to control the rotational speed of a capstan.
That is, during high speed reproduction, a phase reference signal is produced in order to fix a noise bar on an image plane, and a sample-hold pulse is produced from the sample hold circuit for the ATF error signal in synchronization with the rotational phase of the drum. Accordingly, only high speed reproduction having a rotational speed which is N (N is an integer) times as high as that of the drum can be controlled.
On the contrary, more recently, VTRs which can record and reproduce digital signals have been put into practice, and those have been developed as consumer digital VTRs. It is difficult to use a DTF (which is a means in which a head is attached to an actuator such as a bimorph so as to compensate the inclination between a head trace and a track, for preventing lowering of the reproduction RF signal) in a consumer VTR, as is in a business use VTR since it causes the apparatus to be expensive and large-sized. Accordingly, similar to analog VTRs, during high speed search of a digital VTR, a drop of the reproduction signal periodically occurs due to that a head crosses a track.
FIG. 5 shows a head switch pulse HSW and a reproduction RF envelope during a search at a speed which is eleven times as high (in the positive direction). It has been well-known that the reproduction RF signal has a bead-to-bead shape envelope. Further, it has been known that the reproduction level and an error rate for reproduction data greatly affects in digital recording with a certain threshold value. When the above-mentioned threshold value is set to A in FIG. 5, there is a period T during which the reproduction data can be detected, with a period equal to one period (T.sub.0) of the reproduction RF envelopes.
In the digital VTR, video signals are digitalized, and synchronization data and ID information are added for every predetermined unit, and they are recorded on a tape in the form of an assembly of synchronized blocks in a small unit which can be demodulated. During reproduction, the signals are demodulated for every reproduced synchronized block, and are synthesized on a memory corresponding to a monitor screen, which are then delivered.
In consideration with the above-mentioned background, the control for the so-called fixation of a noise bar which has been carried out in the conventional VTR, is not required for the digital VTR, and further, no noise bar flows in a reproduction picture at a tape travel speed other than that of search which is an integer times (N times) as high. Further, on the contrary, an appropriate search speed is not always an integer times as high as that during recording. Accordingly, a problem such that stable control cannot be made when search having a high speed which is not an integer times as high is carried out, has been raised.
Further, in the above-mentioned new tracking system (2fATF system) or a 4fATF system, an ATF error signal having four track periods cannot be obtained, and in a case such that the above-mentioned two frames are recorded in twenty tracks, no tracking control can be made in such a way that a desired head traces a predetermined track in the two frames with a predetermined timing. Thus, there is proposed such a system that track number information in the two frames are mixed as ID with main signals and are recorded, and track jump is made in accordance with a reproduced track number so as to perform just-tracking on a predetermined track in the two frames with an ATF signal by 2fATF.
However, in a system in which a predetermined voltage is temporarily inserted in a tracking signal, as a track-jumping means, if the continuity between the above-mentioned ATF error and the above-mentioned predetermined voltage cannot be taken, stable control cannot be made, and accordingly, a problem such that a reproduced picture becomes unstable for a relatively long time has been raised.

Information signal reproducing apparatus having means for tracking control


Disclosed embodiments provide a renewable power generation apparatus. In embodiments, the renewable power generation apparatus is driven by wind. In other embodiments, the renewable power generation apparatus is driven by water. Disclosed embodiments utilize two cylindrical turbines placed adjacent to each other. A diverter directs wind towards both turbines, causing them to rotate about their respective longitudinal axis. The turbines are coupled to a driveshaft that drives a generator to generate power. Embodiments utilize an airfoil adjacent to each turbine. The airfoil causes air to move faster over the airfoil surface to create low pressure which increases the performance of the turbines. The renewable power generation apparatus of disclosed embodiments is relatively compact compared to a traditional wind turbine. This allows disclosed embodiments to have more flexibility in where they are installed, facilitating local power generation, off-grid applications, and other important environmental applications.

Wind power is one of the fastest-growing energy sources in the world because of its many advantages. The wind is a clean, free, and readily available renewable energy source. Around the world, wind power generation plays an increasingly important role in supplying energy in a clean and sustainable manner.
An additional benefit of wind power is that it is a sustainable source of energy, as wind turbine operation does not directly emit any CO2 or greenhouse gases, helping to meet emission reduction targets and combating climate change. Wind energy is plentiful, readily available, and capturing its power does not deplete our valuable natural resources.
In addition to wind, water can also be used to drive turbines in a clean and sustainable manner. The gravitational pull of the moon and sun along with the rotation of the earth create tides in the oceans. In some places, tides cause water levels near the shore to rise and fall considerably over the course of a tidal cycle. This change in water levels can be used to drive turbines. Tidal turbines are similar to wind turbines in that they have blades that turn a rotor to power a generator. They can be placed on the sea floor where there is strong tidal flow. Both wind and water provide opportunities for increased sustainable energy.


There are here provided a method for biodegrading trichloroethylene which comprises the step of bringing an aqueous medium containing trichloroethylene into contact with microorganisms having a trichloroethylene degrading ability derived from intestines of termites to degrade trichloroethylene; a method for obtaining the microorganisms; a method for remediating a soil by the use of the microorganisms; and a method for biodegrading an chlorinated organic compound with the microorganisms.

1. Field of the Invention
The present invention relates to a method for biodegrading a chloroethylene compound by the use of microorganisms derived from intestines of termites. More specifically, it relates to a biodegradation method useful for the purification of sewage or waste water containing trichloroethylene (TCE), a method for remediating a soil by the utilization of the microorganisms, and a method for obtaining the microorganisms useful for the biodegradation of TCE.
Furthermore, the present invention relates to a biodegradation method using microorganisms in which an chlorinated organic compound degrading activity can be induced with an inducer.
2. Related Background Art
In recent years, various environmental inspections have reported that harmful and less degradable aromatic chemical substances have been detected, and in consequence, much attention has now been paid to environmental pollution with these substances. The influence of these substances on ecological systems is feared.
Therefore, in order to prevent pollution with these less degradable chemical substances, it is required to rapidly develop a technique by which these substances are inhibited from getting into the environment. For example, it is strongly desired to establish a technique by which the less degradable harmful substances can be effectively removed from sewage or waste water. Furthermore, the pollution of a soil with the less degradable harmful substances not only hinders the reutilization of the soil but also causes further escalation of the pollution due to the running of the pollutant into groundwater, which is a serious social problem. Therefore, it is strongly desired to establish a technique by which the escalation of the pollution with the less degradable chemical substances can be prevented and the polluted environment can be remediated.
In particular, TCE is an chlorinated organic compound which has been used in IC industries, dry cleaning and the like, and it is a carcinogen. Thus, the environmental pollution with TCE inclusive of the problem of the soil pollution caused by the pollution of groundwater is a serious social problem. Accordingly, the removal and the degradation of TCE contained in the environment, the purification of sewage or waste water containing TCE, and the remediation of the polluted soil are important themes from the viewpoint of environmental protection.
As a removal treatment and a degradation treatment of TCE, there are an adsorption treatment using active carbon, a degradation treatment utilizing light or heat, and the like. However, a biodegradation treatment using microorganisms is attracting attention from the standpoints of cost and operability.
There is a technique by which the function of microorganisms in a soil is utilized to degrade pollutants in the soil and to thereby eliminate the environmental pollution, and this technique is called bioremediation, because of remediating the soil by the use of the microorganisms. Hence, it can be expected that the bioremediation technique is applied to the remediation of polluted soils such as the vacant lot of a semiconductor manufacturing factory, a site of a metal processing factory, the vacant lot of a chemical plant, and the like.
However, there are not many reports that microorganisms having a TCE degrading ability have been isolated. Examples of the microorganisms having TCE degrading ability are limited, and they include Welchia alkenophila sero 5 (U.S. Pat. No. 4,877,736, ATCC53570), Welchia alkenophila sero 33 (U.S. Pat. No. 4,877,736, ATCC53571), Methylosinus trichosprium OB3b [Whitenbury R. J., Gen. Microbiol, Vol. 61, pp. 205-218 (1970)], Acinetobacter sp. G4 [Nelson M J K et al., Appl. Eviron. Microbiol., Aug., pp. 383-384 (1986); Folsom B. R. et al., Appl. Eviron. Microbiol., May, pp. 1279-1285 (1990); and U.S. Pat. No. 4,925,802, ATCC53617; this bacterium has first belonged to Pseudomonas cepacia but then changed to Acinetobacter sp.], Methylomonas sp. MM2 [Henry S M et al., Appl. Environ. Microbiol., Jan., pp. 236-244 (1991)], Alcaligenes denitrificans ssp. Xylosoxidsans JE75 [Ewers J. et al., Arch. Microbiol., Vol. 154, pp. 410-413 (1990)], Alcaligenes eutrophus JMP 134 [Harker A R & Kim Y. Appl. Environ. Microbiol., Apr., pp. 1179-1181 (1990)], Pseudomonas putida F1 [Gibson D T et al., Biochem., Vol. 7, pp. 2653-2662 (1968); Wackett L. P. & Gibson D. T., Appl. Environ. Microbiol, July, pp. 1703-1708 (1988)], Mycobacterium vaccse JOB5 [Beam H. W. & Perry J. J., J. Gen. Microbiol., Vol. 82, pp. 163-169 (1974); Wackett L. P. et al., Appl. Environ. Microbiol., Nov., pp. 2960-2964 (1989), ATCC29678], Nitrosomonas europaea [Arciero D. et al., Biochem. Biophys. Res. Comm., Vol. 159, pp. 640-643 (1989)], Pseudomonas fluoescens PFL12 [Vandenbergh P. A. & Kunka B. S., Appl. Environ. Microbiol., Oct., pp. 2578-2579 (1988)], Lactobacillus fuctivorans RE [Kunkee, Int. J. Syst. Bact., Vol. 30, pp. 313-314 (1980), J. Appl. Bact., Vol. 34, pp. 541-545 (1971)], Lactobacillus vaginalis sp. nov. [Embley T. M. et al., Int. J. Syst. Bacteriol., Vol. 39, pp. 368-370 (1989), ATCC49540], and Methylosinus trichosprium (Japanese Patent Application Nos. 2-92274 and 3-292970).
In addition, none of the presently known bacteria can meet the practical requirements for the TCE degradation method using the microorganisms and do not possess sufficient degrading ability.
Particularly in the case the microorganisms are used in the soil, it must be considered that the treatment is carried out in a specific environment, i.e. in the soil. The microorganisms to be used are required to have a sufficient TCE degrading activity and to effectively show this activity in the soil, but in the conventionally known bacteria, these points are not sufficient.
Nowadays, the acquisition of the bacteria which can meet practically necessary characteristics is strongly desired.
Such microorganisms are those which preferably have sufficient TCE degrading ability, are different from known bacteria in growth conditions and the like, can be applied to a wide range, are rich in utilizable morphology, and particularly can be effectively utilized in the specific environment of the soil. Examples of such additional requirements include drug resistance and an ability to utilize sucrose.
For example, in the case that the waste water containing TCE is treated, it is required that the microorganisms to be used have a TCE degrading ability, are scarcely damaged in the waste water, and can grow in the severe environment of the waste water. That is, the microorganisms having resistance to many antibiotics and assimilability to various saccharoses can probably successfully grow even in the severe environment.
Thus, the bacteria having the TCE degrading ability and more practically advantageous characteristics than the conventionally known bacteria are strongly required.
Furthermore, in biodegrading chlorinated organic compounds such as TCE, tetrachloroethylene (PCE) and dichloroethylene (DCE) in an environment of a polluted site such as a polluted soil, i.e., an open system, the density of the administered microorganisms by which the biodegradation can be carried out is noticeably decreased owing to predation by protozoans and under the influence of other native bacteria. For this reason, it is often very difficult to increase the density of the microorganisms in compliance with a required treatment ability. In order to increase the density of the microorganisms, there are a method which comprises feeding air to the soil, and a method which comprises forwarding a nutritious solution under pressure. However, although requiring a great deal of energy, these methods cannot effectively increase the number of the bacteria per unit area, and so the treatment ability of these methods remains at a low level on the whole.
In the treatment in a reactor or the like, i.e., in the treatment in a closed system, a good deal of energy for nutrient feed and aeration is also required so as to maintain the density of the microorganisms, as in the above-mentioned open system.
The microorganisms which can degrade the chlorinated organic compounds express an enzyme capable of degrading these compounds, but in order to express this kind of enzyme, an inducer is necessary.
In this case, when a large amount of the inducer is used, the degradation activity of the microorganisms increases, and this fact is known only in an example of tryptophan (WO 90/06901). However, detailed reports regarding the amount of the inducer to be used have not been present at all.

Method for biodegrading trichloroethylene and method for biodegrading chlorinated organic compound by microorganisms


A semiconductor device comprising curable polyorganosiloxane composites is provided where the composites contain at least 0.1 wt % of the 4th and/or 13th group elements of the periodic table. The cured polyorganosiloxane composites may be catalyst-free, have increased stability, and can be used as encapsulation resin at a temperature far lower than 300° C., have excellent light transmission properties (colorless transparency) in a wavelength region of from ultraviolet light to visible light, light resistance, heat resistance, resistance to moist heat and UV resistance, and has excellent adhesiveness toward metal, ceramics, and plastic surfaces over a long period of time.

High brightness light emitting diodes (HBLEDs) offer enhanced energy efficiency thus making them suitable for specialty lighting applications. An LED device is usually composed of the LED chip fabricated onto a substrate and then encapsulated by a material acting as a lens and a luminescence conversion member. The following are the operational requirements of a material to be utilized as an encapsulant of LEDs: optical clarity, high temperature resistant, UV resistant, high refractive index and good adhesiveness toward LED packaging materials.
Encapsulant materials must be optically transparent (greater than 90% transmittance) and should be able to withstand high temperatures, for extended periods of time, without degradation in mechanical and optical performance. The LED device encounters high temperature conditions during the device fabrication (soldering up to 260° C.) and during the actual device operation (around 150° C. for thousands of hours).
Epoxy resins have conventionally been used as a transparent resin for the encapsulation (1, 2). Also, PMMA (polymethylmethacrylate-PMMA), polycarbonate, and optical nylon have been used. However, optical properties of such conventional resins degrade over time. Coloration, or "yellowing", occurs either by heat induced degradation (heat resistance) or via prolonged irradiation with short wavelength light (ultraviolet-resistance). The degradation results loss of mechanical and chemical properties. Due to the loss of physical properties water enters from the encapsulated portion to negatively effect the performance of the LED, and the resin discolors by ultraviolet light emitted from LED to decrease light transmittance of the encapsulated portion. Mechanical degradation of the encapsulant also results in cracking, shrinking and/or delamination from the substrate. Thus, it is desirable to have an encapsulant system that is tough and flexible enough to serve as a mechanical support for the LED component, and relieve internal stress during the device fabrication (prevent damage to LED chip or wires), and during temperature cycling (expansion and contraction of materials with different thermal expansion coefficients).
To overcome the above problems, a fluorine-containing cured product in transparent encapsulation of an emission element has been proposed (3). Although this fluorine-containing cured product has excellent colorless transparency, light resistance and heat resistance as compared with the epoxy resin, it has poor adhesion to LED's and it is liable to peel from the material to be encapsulated. The LED is generally made of the following materials (GaN chip, phosphors) and has higher refractive index in the visible light region from 2.5 to 3.0. The fluorine-containing cured encapsulant has low refractive index of light when compared to GaN, phosphor components in the same optical wavelength. Therefore, the pick-up efficiency of light in the same wavelength region has not always been sufficient in the fluorine-containing cured product.
To solve the above problems, LED encapsulated with a glass prepared with a sol-gel method was developed (4). This encapsulant material makes it possible to reduce hygroscopicity and decrease discoloration, and improve heat resistance. However, with sol-gel glass, fine pores are liable to remain and cracks can be easily generated. When water enters the fine pores or crack sites, it affects the performance of the LED. In general, the glass has poor adhesion when compared with a resin.
It has also been proposed that a low melting glass is heat melted, and LED is transparently encapsulated with the melt (5). However, where a low melting glass is generally heat melted, it is necessary to heat the glass to a temperature from 400 to 700° C. Therefore, a phosphor used in LED may undergo heat deterioration.
To overcome those problems, a silicone resin (polyorganosiloxane) having excellent heat resistance and ultraviolet resistance was used as a substitute of the epoxy resin. However, silicone resins up to now tend to scar easily, and are not yet sufficient when considering the combined characteristics: adhesion, colorless transparency, heat resistance, resistance to moist heat and UV tolerant (5, 6, 7, 8, 9).
With the recent development of GaN-based devices which emit short wavelength radiation such as blue light or ultraviolet light, and subsequently white light by combining these light emitting diodes with fluorescent phosphors, the material requirements for the encapsulant have significantly increased. Materials should be able to withstand exposure to radiation of high intensity UV light and temperature up to around 200° C. without degradation in optical and mechanical properties.
Therefore, there is a need for robust LED encapsulants with superior optical clarity, high temperature-resistance, UV-resistance, higher refractive index, and with variable elastic properties including adhesiveness toward the materials used on the surface of the LED packages (10, 11). The present invention allows such properties to be achieved. There is also a need for LED encapsulants with varying mechanical properties, without sacrificing their optical clarity, high temperature-resistance and UV-resistance. The present invention allows such properties to be achieved, as well.

Semiconductor device comprising high performance encapsulation resins

The Regents of the University of California


A system for computer-managing information of baggage to be loaded in an aircraft. The system comprises a response circuit attached to the baggage and a reader disposed at a classification point of the baggage. The response circuit operates to input and store baggage information indicative of at least a flight name of the aircraft and the owner of the baggage, and in response to a question electromagnetic wave, outputs a response electromagnetic wave containing the baggage information. The reader transmits the question electromagnetic wave to the response circuit means and to receive the response electromagnetic wave from the response circuit, thereby reading out the baggage information so that the baggage can be classified in accordance with the read baggage information. Also included is a computer for inputting and storing the baggage information read by the reader and for inputting and storing information representative of the owner of the baggage, the computer performing a verification between the baggage owner and the baggage on the basis of the inputted baggage information and the inputted owner information.

The present invention relates to an aircraft baggage managing system for managing baggages to be loaded into an aircraft.
In general, when baggages not brought into the cabin are encased of the aircraft, they container and loaded into a storage compartment of the aircraft. Under such a situation, decides to not get on the aircraft, the specified the fact that the passenger has checked a baggage, the specified baggage, once encased in the aircraft container, is required to be taken out from the aircraft. However, a conventional system does not have a function to sufficiently manage the baggage-loaded information, and hence difficulty is encountered in sorting out the baggage actually loaded into the aircraft.

Aircraft baggage managing system utilizing a response circuit provided on a baggage tag


A process for the development of an imagewise exposed photographic recording material containing more than 200 mg/m.sup.2 of silver comprises subjecting the photographic recording material to a development/amplification step using a developer/amplifier solution containing an oxidizing agent, and controlling the process temperature within the range of from 20 to 50.degree. C. and the process time between 5 and 20 seconds. After the development/amplification step, the photographic material can be immediately subjected to a bleach-fix step, and staining is avoided.

Redox amplification processes have been described, for example in British Specifications Nos. 1,268,126; 1,399,481; 1,403,418; and 1,560,572. In such processes color materials are developed to produce a silver image(which may contain only small amounts of silver) and treated with a redox amplifying solution (or a combined developer/amplifier) to form a dye image.
The developer/amplifier solution contains a color developing agent and an oxidizing agent which will oxidize the color developing agent in the presence of the silver image which acts as a catalyst.
Oxidized color developer reacts with a color coupler to form the dye image. The amount of dye formed depends on the time of treatment or the availability of the color coupler and is less dependent on the amount of silver in the image than is the case in conventional color development processes.
Examples of suitable oxidizing agents include peroxy compounds including hydrogen peroxide and compounds which provide hydrogen peroxide, e.g., addition compounds of hydrogen peroxide such as perborates and addition compounds of hydrogen peroxide with urea. Other oxidizing agents include cobalt (III) complexes including cobalt hexammine complexes; and periodates. Mixtures of such compounds can also be used.
In color photography development (whether redox or conventional) it is necessary at an appropriate stage to remove the silver image which, if left behind would darken the dye image. Also it is necessary to remove unused silver halide because it darkens on exposure to light. To remove the silver, the practice has been to convert the silver to silver halide with a suitable oxidizing agent known in the art as a bleach and then remove the silver halide with a fixing agent.
Suitable oxidizing agents are potassium ferricyanide, or ferric iron complexed with ethylene diamine tetraacetic acid acting in the presence of potassium bromide. The two steps may be combined using a solution called a bleach-fix or blix.
In the case of a bleach-fix employed after a redox amplification, the solution only needs small amounts of iron (III) and thiosulfate because there is usually only a small amount of silver to remove.
U.S. Pat. No. 5,200,301 relates to a color photographic silver halide material which is particularly suitable for colored machine-readable identification systems. Machine-readable detection systems normally operate by I.R. absorption of the data applied and this patent is concerned with the problem of providing a color photographic material which produces a clear brilliant dye image and also shows adequate I.R. absorption in the data part, the I.R. zones being photographically produced. Although directed to a different problem from that with which the present invention is concerned, a process for the redox development of photographic materials containing greater than 200 mg/m.sup.2 of silver is described in which the development stage is faster than conventional. A subsequent fixing step is disclosed but there is no bleaching step with the result that the silver is left in the developed photographic material.
Redox development/amplification is intended primarily for photographic materials containing low amounts of silver, especially for low silver photographic papers, i.e., containing less than 200 mg/m.sup.2 of silver. The time of development using a redox system with low silver photographic paper is broadly similar to that for a conventional development process applied to conventional, i.e., higher silver-containing materials.
However, it is very desirable to be able to reduce the development time because this enables more photographic material to be processed with existing processing equipment or for the processing equipment to be made smaller.

Process for the development of photographic materials


An N-wire interleaved differential multiplexer. The N-wire interleaved differential multiplexer may be formed by interleaving the channels and corresponding switches of N one-wire multiplexers. Each of the switches of the interleaved differential multiplexer may be controlled independent from the other switches to provide a signal path between a DUT stack and a measurement device. To test a first DUT, two switches of the interleaved multiplexer are closed to connect the terminals of the first DUT to the measurement device. To switch from testing the first DUT to testing a subsequent DUT, one of the previously activated switches is opened, one is kept closed, and a different switch is closed. The testing process may “walk” up or down the switch channels of the interleaved multiplexer one switch at a time to test each of the DUTs of the DUT stack.

1. Field of the Invention
This invention relates to switching devices and, more particularly, to an interleaved differential switching apparatus.
2. Description of the Related Art
Typically, a traditional 2-wire differential switch module is used to test circuits that include several devices under test (DUTs) linked in series, such as battery stacks and fuel cell stacks. Traditional 2-wire differential switch modules usually include 2-wire channels that connect to common nodes between the DUTs. In this design, the two wires of each channel connect to a common node between two of the DUTs; therefore, each of the common nodes has two redundant connections.
The 2-wire channels are typically implemented using double-pole, single throw (DPST) switches, which means that two switch contacts are controlled by a single coil and cannot be operated independently. When switching from testing one DUT to another, the two switch contacts corresponding to the active 2-wire channel need to be deactivated, and then two other switch contacts corresponding to another 2-wire channel need to be activated. Since DPST switches are used, each 2-wire channel in this configuration requires 2 switch contacts. Therefore, traditional 2-wire differential switches may contain redundant switch contacts, which increase the size and cost of the switch module.
Many other problems and disadvantages of the prior art will become apparent to one skilled in the art after comparing such prior art with the present invention as described herein.


A microlens has a surface with an effective index of refraction close to the index of air to reduce reflection caused by change in indices of refraction from microlens to air. The microlens having an index of refraction approximately the same as that of air is obtained by providing a rough or bumpy lens-air surface on the microlens. Features protrude from the surface of a microlens to create the rough surface and preferably have a length of greater or equal to a wavelength of light and a width of less than a sub-wavelength of light, from about 1/10 to ¼ of the wavelength of light. The features may be of any suitable shape, including but not limited to triangular, cylindrical, rectangular, trapezoidal, or spherical and may be formed by a variety of suitable processes, including but not limited to mask and etching, lithography, spray-on beads, sputtering, and growing.

Microlenses are used to funnel light of a larger area into a photodiode of an imager pixel, for example. Microlenses also can be used to trap light into a solar cell, as well as to project light from a light-producing component of a display. Advanced products and systems that utilize microlenses in these and other similar ways include, without limitation, digital cameras, flat-panel visual displays, and solar panels. Such products and systems are used in a wide variety of applications ranging from mobile phone displays and flat-screen televisions to mapping the solar system, and beyond.
The direction that light is propagated through two media, such as air and a lens, is based on the relationship between the refractive indices of the media. Snell's Law (Eq. 1) relates the indices of refraction n of the two media to the directions of propagation in terms of angles to the normal:n1 sin θ1=n2 sin θ2  (1)
The index of refraction (n) is defined as the speed of light in vacuum (c) divided by the speed of light in the medium (v), as represented by Eq. 2:n=c/v  (2)
The refractive index of a vacuum is 1.000. The refractive index of air is 1.000277. Representative materials used in microlens and semiconductor device fabrication include oxide, with a refractive index of 1.45, and nitride, with a refractive index of 2.0. FIG. 1 illustrates the relationship between the indices of refraction at the air-microlens interface. The graph on the right side of FIG. 1a shows a constant index of refraction in the air and a different constant index of refraction at all depths of the microlens, and therefore a sharp increase in the index of refraction at the air-microlens interface.
When light travels from a medium with a low refractive index, such as air, to a medium with a high refractive index (the incident medium), such as nitride, the angle of light with respect to the normal will increase. In addition, some light will be reflected. This will reduce the efficiency of the imaging system, since not all of the light hitting the lens will travel through the lens to the photodiode, for example.
Reflection at the interface of two different media can be quantified by the following formula (Eq. 3):R=(n1−n2)2/(n1+n2)2  (3)
Therefore, reflection from the interface between the two media can be reduced by matching their indices of refraction as closely as possible. As noted above, the refractive index of oxide is significantly closer to 1.0 than that of nitride. By providing an outer layer on a lens having an index of refraction closer to that of the surrounding medium, such as that of air, reflection is reduced and the efficiency and accuracy of the lens is improved.
Thus, it would be useful to have a microlens having a graded refractive index profile to reduce light reflection.

Method and apparatus for reducing microlens surface reflection


Systems, methods, and storage media for performing actions in response to a determined spoken command of a user are disclosed. Exemplary implementations may: output audio information representing sounds within audible range of a mobile client computing platform in an ongoing manner; cause the audio information to be wirelessly transmitted over a network; receive the audio information transmitted from the mobile client computing platform; perform speech recognition on the audio information to identify any spoken instances of a predetermined keyword; responsive to identification of a spoken instance of the predetermined keyword, identify a spoken command in speech temporally adjacent to the spoken instance of the predetermined keyword that is present in the sounds represented by the audio information; and effectuate transmission of instructions corresponding to the spoken command to the wireless transmitter of the mobile client computing platform to cause the mobile client computing platform to execute the spoken command.

Systems performing actions based on spoken commands are known (e.g., Siri, Alexa, Google, etc.). However, the known systems must first detect a wakeword (e.g., "Hey Siri") to initiate further detection of the spoken command. Detection of the wakeword is typically performed on a client device local to the user, and with further processing of the user's speech after detection of the wakeword being performed on a server. The uploading of the user's speech from the client device to the server may be responsive to detection of the wakeword.


An electric four wheel drive system of a dual clutch type includes dual clutches selectively preventing power from being transmitted to both driving wheels from a motor. A motor housing is mounted on the motor and a hydraulic valve assembly mounted on the motor housing providing operating hydraulic pressure to the dual clutches. The hydraulic valve assembly controls the dual clutches using the hydraulic pressure generated by a hydraulic pressure generator of a regenerative braking system.

An electric four wheel drive (e-4WD) system can achieve both of a 4WD function and a hybrid electric vehicle (HEV) function by driving the rear wheels of a front-engine in a front-wheel drive vehicle.
Vehicles equipped with an electric four wheel drive system have an engine and a transmission connected to the front wheels. The electric four wheel drive vehicles have a power generator which charges a high-voltage battery using the mechanical energy from the engine.
A motor and a reduction gear, that are driven by electrical energy, are connected to the rear wheels, and the output from the motor and the reduction gear can be transmitted to the rear wheels.
In a regenerative braking mode, braking and inertia energy can be recovered by the motor, and the high-voltage battery can be charged by the recovered energy.
As a type of the electric four wheel drive system, there is a dual clutch type equipped with a dual clutch selectively preventing power transmitted to the rear wheels from the driving elements of the reduction gear and the motor.
An electric four wheel drive system of the dual clutch type includes power transmission mechanisms at both sides of a drive shaft of a hollow motor and multi-plate clutches selectively connecting driving elements with the rear wheels.
The electric four wheel drive system of the dual clutch type can selectively connect the driving elements with the rear wheels by means of the multi-plate clutches and can achieve torque vectoring that actively distributes driving torque to the rear wheels.
The electric four wheel drive system of the dual clutch type is equipped with hydraulic pressure generators that operate the multi-plate clutches, respectively, in order to achieve torque vectoring. The hydraulic pressure generator includes a hydraulic pump disposed in a housing and generating hydraulic pressure, a hydraulic motor providing a driving force to the hydraulic pump, and hydraulic valves and hydraulic lines for supplying the hydraulic pressure to the clutches, respectively.
The electric four wheel drive system of the dual clutch type can control the hydraulic pressure generator in accordance with a torque vectoring duty calculated on the basis of conditions such as understeer and oversteer.
According to the related art, the electric four wheel drive system of an dual clutch type can distribute the torque of the driving elements to one of the rear wheels by controlling the multi-plate clutches by means of the hydraulic pressure generator in accordance with traveling conditions of the vehicle.
However, since the electric four wheel drive system of the dual clutch type includes the pump housing, the hydraulic pump, the motor, the valve housing, and the hydraulic valves, which are components of the hydraulic pressure generator for driving the multi-plate clutches, it is disadvantageous in terms of the entire weight, cost, size, fuel efficiency. In addition, the structure is complicated.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and, therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

Electric four wheel drive system of dual clutch type for providing torque vectoring and control method of the same