In a method of manufacturing a multi-nozzle ink jet head having a plurality of nozzles, cross talk between adjacent elements is suppressed. The head has the nozzles (12), pressure chambers (15), and bimorph drivers. The bimorph drivers have piezos (19) formed on a diaphragm (18). The diaphragm (18) has linear parts (18-1) that convert the generated force from the piezos (19) into displacement, and non-linear parts (18-2) that are provided between the linear parts (18-1) and diaphragm fixing parts. Due to the non-linear parts (18-2), transmission of strain energy to the fixing parts is suppressed, and hence cross talk is suppressed.

FIG. 14 is a drawing of the constitution of a conventional multi-nozzle ink jet head. This head 10 shows an example of the application of bimorph actuators in which a diaphragm 102 and a piezo elements 101 are laminated together as driving elements. Regarding the method of producing this head, a plurality of individual electrodes 100 are formed by sputtering on an MgO substrate, not shown, and the piezos 101 are further laminated on to a thickness of a few μm, and pattern formation is carried out. After this, a metal (for example Cr) that will become the common electrode cum diaphragm 102 is formed to a few μm over the whole surface, thus forming the bimorph structures.
A pressure chamber forming member (dry film resist) 103 and a nozzle forming member 105, which are prepared separately, are then joined on, with positional alignment being carried out with the individual electrodes 100 of the bimorph structures. After that, the MgO substrate is removed by etching, thus completing the multi-nozzle head plate 10.
Regarding the operation of this head 10, ink is fed to the head 10 from an ink tank, not shown, and then within the head 10, the ink is fed through a common channel and ink supply channels to pressure chambers 104 and nozzles 106. Driving signals are applied to the individual electrodes (the electrodes corresponding to the respective nozzles) 100 from a driving circuit, whereupon, due to the piezoelectric effects of the piezo 101, the diaphragm 102 bends towards the inside of the pressure chamber 104 as shown by the dashed line in FIG. 14, and hence ink is ejected from the nozzle 106. The ink forms dots on a printing medium, thus forming a desired image.
Regarding the deformation during driving shown by the dashed line in FIG. 14, a strain force due to the piezoelectric effects of the piezo 101 (in particular the transverse effect orthogonal to the electric field) acts as a bending moment at the bending section neutral axis due to differences in the sectional shape (in particular the thickness) and the Young's modulus between the electrode 100, the piezo 101 and the diaphragm 102, and hence the bimorph structure which comprises the electrode 100, the piezo 101 and the diaphragm 102 as a whole bends.
To make this bending act so that the ink in the pressure chamber 104 flows, it is necessary to fix the bimorph structure to the pressure chamber 104. As a result, it becomes possible for the surface of the diaphragm 102, which bends with the fixed part as a reference position, to change the volume of the pressure chamber 104, whereupon ink is ejected.
As shown in the schematic drawing of FIG. 15, in the multi-nozzle ink jet head 10 in which the volume of the pressure chambers 104 is changed by bending of the diaphragm 102, if the density of the nozzles 106 is made high, then the walls 103 between the pressure chambers 104 communicating with adjacent nozzles 106 (the pressure chamber walls) become thin. That is, the fixing parts of the diaphragm 102 become narrow. For example, in a 150 dpi head, the nozzle spacing is about 169 μm, and hence it is necessary to make the thickness of the pressure chamber walls 103 35 μm.
This reduces the rigidity of the fixing parts 103 of the diaphragm 102, and hence the fixing parts 103 no longer function sufficiently as fixed ends of the diaphragm 102. As a result, in the case of a structure in which adjacent pressure chambers 104 are covered by the same diaphragm 102, when a single part of the diaphragm bends (single-element driving), the part of the diaphragm for the adjacent element is pulled in in the direction A of the bending, i.e. it is difficult for local bending of only the driven part to occur. Moreover, as shown in FIG. 15, when various parts of the diaphragm 102, including the parts at adjacent elements, bend together (multi-element driving), the parts of the diaphragm 102 on either side of the fixing part 103 pull against one another in the directions of the arrows A and B, and the two pulls balance one another, and hence it is easy for local bending of only the driven parts to occur.
In this way, mechanical driving interference (cross talk) occurs in which the bending of the diaphragm 102 differs according to the driving state (single-element driving or multi-element driving). In the ink jet head, this manifests itself as fluctuations in the ink flight characteristics, resulting in a drop in printing quality.
Moreover, a technique is known for dividing a single diaphragm 102 into parts for each of the pressure chambers 104, but with thin pressure chamber walls 103, it is very difficult to secure the reliability of the diaphragm fixing parts (the structure that functions as fixed ends for the diaphragm and also seals the pressure chambers) if the nozzle density is high. Moreover, even if the diaphragm is divided, the strain energy that the piezos 101 exert on the fixed ends of the diaphragm 102 will not change, and hence the energy transmitted to adjacent elements via the pressure chamber walls 103 will not change. As a result, in a high-density head in which the pressure chamber walls are thin, dividing the diaphragm is not an effective measure for solving the problem, and cross talk cannot be prevented.

Method of manufacturing a multi-nozzle ink jet head


A bottle assembly is described having a battery-powered heated elongated spout. A heater embedded along the length of the spout is typically activated by a switch provided on the assembly. A LED indicator is also typically provided to indicate when the heater is activated. The LED can also function as a battery level indicator that changes color when the battery packs level of charge is depleted to a predetermined level. A charging port is provided through which the battery pack can be recharged using a suitable charger.

Traditionally, to maintain a beverage at an elevated temperature, an insulated bottle or container is used. The insulation often comprises an evacuated space maintained between the inner and outer shells of the bottle to slow heat transfer but not eliminate it. Accordingly, over time and depending on the surround ambient conditions, the beverage contained in the bottle cools. Essentially, the effective use time of the insulated bottle is limited to several hours before the liquid contents cool to a temperature below a desired minimum.
Actively heated bottles and containers are known but the amount of energy required to heat the liquid contents and maintain the liquid at a desired temperature is significant. Typically, these types of container are used with insulation and employ AC electric heaters that need to be plugged into an outlet to operate. Using batteries to power the heater is just not practicable given the size and weight of the battery or batteries required to heat and maintain the liquids temperature for any reasonable period of time.


A system for forming different types of clamshell components including a moveable base, a stationary base, and a squeezer assembly capable of accommodating different types of clamshell components having different lengths, shapes, locations of piercings. The squeezer assembly includes interchangeable squeezer elements. To switch between forming a first type of clamshell component and a second type of clamshell component, one of the two bases is moved relative to the other of the two bases and/or squeezer units for forming the first type of clamshell component are replaced with squeezer units for forming the second type of clamshell component. Reconfiguring the bases and interchanging the squeezers of a clamshell tool, instead of replacing an entire clamshell tool with a different clamshell tool, minimizes lost productivity time, reduces capital costs, and eliminates the problem of storing several different clamshell assembly tools.

In the automotive industry, vehicles are mass-produced using complex assembly line processes, in which each vehicle is assembled together as it passes through a plurality of different assembly stations. Separate assembly lines may also be provided for assembling vehicle sub-assemblies and components, which are subsequently incorporated into one of the vehicles that is being assembled on the main assembly line. Typically, a single type of vehicle includes many different types of clamshell components, which may be used in engine cradles, as frame cross-members, etc.
In the case of clamshell components, typically upper and lower shells, which may or may not be substantially identical to each other, are aligned and joined together along overlapping edge portions or flanges. A few specific and non-limiting examples of common joining techniques include metal inert gas (MIG) welding and spot welding. Different types of clamshell components may have different lengths, different contours along one or more of the outer surfaces, different spacing between piercings, etc. In order to ensure that the upper and lower shells are joined securely one to the other, overlapping edge portions of the upper and lower shells are pressed together using squeezers that are customized for the particular component being formed, and the joining is performed during squeezing. In particular, the squeezers are customized to conform closely to the contours along the overlapping edge portions of the upper and lower shells, so as to avoid forming any gaps along the resulting joint.
Prior art strongback machines have squeezers that squeeze the clamshell components along the weld face, in order to close gaps in clamshell components as described above. These machines are custom-built, and are not re-usable for different components. In particular, such strongback machines do not accommodate variable widths, heights, and/or lengths for manufacturing various clamshell components. Of course, high tooling costs are associated with the purchase of custom tools for forming each of a plurality of different clamshell components. Further, whenever a different clamshell component needs to be manufactured there is lost production time associated with switching out one strongback machine and replacing it with a different strongback machine that supports production of the different clamshell component. Further still, storing a plurality of different strongback machines consumes floor-space within manufacturing facilities and may contribute to unsafe working conditions.
It is desirable to provide a clamshell assembly fixture that overcomes at least some of the above-mentioned limitations of the prior art.


Steering logic for a self-propelled vehicle having a plurality of wheels includes the steps of receiving translational velocity and angular velocity commands, determining the resultant velocity and steer angle of each wheel, and determining the wheel offset correction for each wheel based on the scrub radius of each wheel and the angular velocity command.

Examples of self-propelled mowers are shown in U.S. Pat. Nos. 7,024,842 and 7,024,843 assigned to Deere & Company of Moline, Ill. The self-propelled mower frame supports wheel assemblies, a propulsion unit, and one or more mowing decks. Each wheel assembly may be associated with a corresponding wheel, electrical steering motor, and electrical drive motor. A controller controls a steering direction of orientation of the corresponding wheel via application of electrical energy to the corresponding drive motor consistent with maneuverable movement of the mower. The propulsion unit is capable of rotating at least one cutting blade housed under a mower deck. Self-propelled mowers may be riderless, or may provide an operator station on the vehicle platform.
Each wheel assembly may include a spindle assembly that is affixed to the frame or operably attached to the frame via a suspension component. The spindle assembly may provide a housing for bearings that receive a shaft. One end of the shaft may be associated with a yoke and the opposite end of the shaft may be associated with a steering assembly. The yoke may provide a mounting for a drive motor, a tire, and a drive encoder. The steering assembly may include a steering motor, a steering encoder, and a steering gearbox. The steering gearbox may provide gear reduction such that a lower torque motor (e.g., a lightweight durable motor) may be used as the steering motor. The steering motor may allow the shaft and yoke to pivot freely from zero to 360 degrees when no power or a certain control signal is applied to the steering motor. In an alternate embodiment, the steering gearbox may permit the steering motor to be disengaged from turning or changing the orientation of the wheel by a clutch, a gear mechanism or another mechanical or electromechanical structure.
When drive motors of wheels on a self-propelled vehicle such as a mower are at rest, operating the steering motors to steer the mower wheels in place may scuff the ground surface. Scuffing is a problem in areas where high quality mowing is important, including athletic fields. It is desirable to reduce or eliminate scuffing when steering while the mower wheels are not rotated by the drive motor.
Steering a self-propelled vehicle with the mower wheels in place also may require high steering torque. This requires higher torque motors and other components, and may be detrimental to the durability and performance of a self-propelled vehicle. It is desirable to reduce the required torque for steering a self-propelled vehicle when the drive motor for the wheel or wheels is at rest.
Steering a self-propelled vehicle with the mower wheels in place also may have a tendency to move the mower. It is desirable to keep the mower in a stationary position when steering the mower with the wheels in place.
In general, wheel assemblies on self-propelled vehicles such as mowers should be able to rotate continuously about a steer axis. This requires transmitting the power to drive the wheel across the steering joint for example, electric power for a propulsion motor must be transmitted from the vehicle frame down a tube or shaft and across the steering joint to a motor positioned on or adjacent the wheel hub. To transmit drive or traction power across the steering joint, slip rings, such as mercury wetted slip rings, may be required. For example, U.S. Pat. No. 5,450,320 relates to slip rings used to transmit power for the drive system in an automated guided vehicle. Slip rings may be expensive and may raise environmental concerns. It is desirable to eliminate the use of slip rings for steering self-propelled vehicles, and use less costly and more environmentally friendly alternative.


A webbing retracting device that may prevent entering of an end-lock state when a spool rotates in the pull out direction on rebound just after completion of taking up of the webbing belt. A restriction weight is provided on a V gear. The restriction weight moves in the pull out direction relative to the V gear by acceleration when the V gear is rotated in the take up direction, and furthermore, the restriction weight pivots about a support pin under centrifugal force due to rotation of the V gear and attains a contact position. In such a state, even if the inertial mass attempts to displace toward the lock activation direction, the restriction weight interferes with the inertial mass and restricts displacement of the inertial mass toward the lock activation direction.

1. Technical Field
The present invention is related to a webbing retracting device for taking up and storing a webbing belt for restricting the body of a vehicle occupant sitting in a seat.
2. Related Art
In webbing retracting devices that configure vehicle seat belt devices there are lock mechanisms provided that restrict rotation of a reel shaft in a pull out direction when a vehicle suddenly decelerates, for example as described in Japanese Patent Application Laid-open (JP-A) No. 05-193441 (Patent Publication 1). A lock gear configuring the lock mechanism described in Patent Publication 1 is coaxially rotatable relative to the reel shaft, and when the reel shaft rotates in the pull out direction relative to the lock gear, coupled to this relative rotation, the teeth of each of a main pawl and a backup pawl mesh with internal teeth formed on both side walls of a frame, and rotation of the reel shaft in the pull out direction is restricted. There are two types of configuration for generating relative rotation between the reel shaft and the lock gear, one being a deceleration detecting means. The deceleration detecting means is provided with an inertial body that moves with inertia when a vehicle suddenly decelerates, and an engaging pawl, pushed up by an inertially moved inertial body, engages with external teeth on the lock gear, thereby restricting rotation of the lock gear, and the lock gear rotates relative to the reel shaft that is rotating in the pull out direction.
Another configuration for generating relative rotation between the reel shaft and the lock gear is another inertial body, separate to the inertial body of the deceleration detection means, provided on the lock gear. This inertial body is connected to the lock gear by a spring, but when the reel shaft together with the lock gear suddenly rotates in the pull out direction, a rotational lag occurs of this inertial body against the biasing force due to the spring and relative to the lock gear. Along with the rotation relative to the lock gear due to the rotational lag, the inertial body moves to the outside in the rotational radial direction of the lock gear, and meshes with inner ratchet teeth that are formed on the inside of a cover, and rotation of the inertial body, and therefore rotation of the lock gear, is stopped. In this manner, by stopping the rotation of the lock gear, the lock gear rotates relative to the reel shaft that is rotating in the pull out direction.
However, just after completion of taking up the webbing belt by the reel shaft if the lock mechanism is unintentionally actuated, then the reel shaft is not able to rotate in the pull out direction from this state, entering a so-called "end-lock state". In such an end-lock state, since the reel shaft is not able to rotate in the pull out direction, pulling out of the webbing belt becomes difficult. Therefore, in the above Patent Publication 1, when taking up of the webbing belt is competed it is configured such that the external teeth of the lock gear and the engagement pawl of the deceleration detection means do not mesh together, so as to prevent an end-lock state arising.


An electrophotographic photoreceptor includes a conductive substrate, and a photosensitive layer provided on the conductive substrate, and an outermost surface layer of the electrophotographic photoreceptor is constituted with a polymerized product or crosslinked product of a composition including at least one selected from reactive compounds represented by the formulae (I) and (II) and a non-reactive charge transporting material, a content of the non-reactive charge transporting material in the composition is from 5% by weight to 40% by weight based on the weight of the outermost surface layer, and a content of the unreacted reactive compound in the outermost surface layer after forming the outermost surface layer is 3% by weight or less based on the weight of the outermost surface layer.

1. Technical Field
The present invention relates to an electrophotographic photoreceptor, a process cartridge, and an image forming apparatus.
2. Related Art
Generally, an electrophotographic image forming apparatus has the following configurations and processes.
That is, the surface of an electrophotographic photoreceptor is charged to desired polarity and potential by a charging unit, and the charge is selectively removed from the charged surface of the electrophotographic photoreceptor by image-wise exposure, thereby forming an electrostatic latent image. The latent image is then developed into a toner image by adhering a toner to the electrostatic latent image by a developing unit, the toner image is transferred onto an transfer medium by a transfer unit, and then the transfer medium is discharged as an image formed material.
Recently, electrophotographic photoreceptors have been increasingly used in the field of copying machines, laser beam printers, and the like in view of advantages of obtaining high printing quality with a high speed.
As electrophotographic photoreceptors used in image forming apparatus, electrophotographic photoreceptors used in the related art, using inorganic photoconductive materials such as selenium, selenium-tellurium alloy, selenium-arsenic alloy, and cadmium sulfide (inorganic photoreceptors) have been known, but recently, organic photoreceptors using organic photoconductive materials having superior advantages in views of low cost, manufacturability, and disposability (organic photoreceptors) are mainly used.
In order to attain a longer lifetime and higher reliability of the electrophotographic photoreceptor, it has been proposed to provide a protective layer on the surface of an electrophotographic photoreceptor to improve the strength.
The materials for forming a protective layer have been proposed.

Electrophotographic photoreceptor, process cartridge, and image forming apparatus


A plug-in logic board for use in an arbitration mechanism is disclosed. The disclosed arbitration mechanism includes two or more request processing units, two or more grant processing units and a common broadcast medium. The request processing units and the grant processing units use the common broadcast medium to control the coupling between requesters and resources on a first come, first served basis. The disclosed logic board includes a request processing unit coupled to the common broadcast medium, a grant processing unit coupled to the common broadcast medium, and an input/output unit coupled to an electronic operating device. The input/output unit passes a resource type request signal from the electronic operating device to the request processing unit, and passes a status signal received from the electronic operating device to the grant processing unit. The input/output unit further outputs a grant signal received from the request processing unit to the electronic operating device. The disclosed logic board further includes a means, responsive to said resource type request signal, said status signal, and said grant signal, for coupling a requester type electronic operating device to a resource type electronic operating device using a resource access path.

In modern electronic systems, resource arbitration is often required to determine the order in which requesters will have access to shared resources. As the size increases in electronic systems, for example computer systems, or for a second example, communication systems including telephone systems, or for a further example, computer local area networks and wide area networks, the number of requesters becomes large and also the number of resources becomes large. The resources may be divided into distinct types with multiple instances of many of the types. Arbitration for the resources becomes more difficult as the number of requesters and the number of resources both become large.
Also, in computer communications the arbitration process must be fast because the connect time for transmission of a data packet may be only a few microseconds to a few milliseconds. And the arbitration must be fast enough to provide efficient switching for such short connect times.
The combination of fast arbitration for large numbers of requesters and resources puts a severe strain on arbiter design, and present arbiters are either too slow or do not scale well to large numbers of requesters and large numbers of resource types, each with multiple instances.
Examples of known arbitration systems follow.
As a first example of a known arbitration system, one type of resource arbitration is known as round-robin polling. In the round-robin polling scheme, all requesters for the shared resource are either logically or physically arranged into a ring. The arbiter polls the requesters in the order in which they are arranged in the ring. The arbiter grants access to the shared resource to the first requester in the ring which has an active request. When a requester has finished with the resource, the arbiter resumes polling at the next requester in the pre-established order. An example of a distributed round-robin polling scheme is a token-passing local area network such as IEEE standard 802.5.
As a second example of a known arbitration system, another type of resource arbitration is known as fixed-priority polling. This scheme is similar to round-robin arbitration except that when the shared resource becomes free, the polling of the requesters always restarts at a constant pre-designated point, i.e., the requester having the highest priority.
As a third example of a known arbitration system, this fixed priority polling is also done with "request snapshots" which attempt to prevent any particular requester from being unable to obtain access to a shared resource for an extended period of time. This can happen, for example, to low priority requesters in the fixed-priority polling scheme.
In the snapshot scheme, a "snapshot" of all outstanding requests is taken after all requests of a previous "snapshot" have been serviced. All of the requests in the "snapshot" are then serviced according to the designated polling discipline. Any new requests which occur during the time period after the "snapshot" is taken are inhibited or ignored until the next snapshot is taken. The request snapshot scheme guarantees that even the lowest-priority requester will be serviced so long as its request appears in a snapshot. Further, all requesters will each receive the shared resource no more than once per snapshot. An example of a distributed fixed-priority polling scheme with snapshots is the IEEE P1196 NuBus scheme.
As a fourth example of a known arbitration system, another arbitration scheme, called contention arbitration, permits one or more requesters to attempt to seize the shared resource at any time when the requesters perceive that the resource is available. A potential problem with this scheme, however, occurs when two or more requests collide with each other without anyone gaining access to the shared resource. Schemes have been developed to overcome this obstacle so that when a collision does occur, the requesters involved follow a designated policy for re-attempting their request. This policy can include waiting for a random time interval after the collision is over before regenerating the request. An example of contention arbitration is the IEEE 802.3 standard Ethernet Carrier-Sense-Multiple-Access/Collision-Detect scheme.
As a fifth example of a known arbitration system, a still further method of resource arbitration is known as queuing. In the queuing scheme, all requests are entered into a storage area called a queue. Requests are serviced from the queue according to a designated queuing discipline with the most common queuing discipline being a first-come, first-served policy. There are a variety of ways to implement a queue scheme, including the use of shift register memories, circular buffers, and linked lists.
Arbitration schemes are further classified as either centralized or distributed arbitration schemes. In a centralized scheme, requesters are separate from the arbiter and the arbiter is solely responsible for implementing the designated arbitration scheme. In distributed arbitration, however, the arbiter logic is distributed or divided throughout the system so that logic is closely associated with each requester and or each resource. Therefore, each requester is responsible for implementing a designated portion of the arbitration protocol. Both centralized and distributed arbitration schemes have advantages depending upon the specific application. The main differences are in the number and type of signal paths between requesters and the arbiter and in their fault tolerance characteristics.
All of these arbitration schemes, however, tend to be limited and are not acceptable either in rapid arbitration for computer communications or when used with a computer system having a large number of requesters and resources, or systems with multiple types of resources. For example, in prior arbitration schemes, when multiple resources having multiple instances were involved, multiple arbiters were frequently duplicated for each resource type, thereby increasing the cost and resulting in burdensome redundancy in the system.

Fast arbiter having easy scaling for large numbers of requesters, large numbers of resource types with multiple instances of each type, and selectable queuing disciplines

395325
XCL DIG 1
XCL DIG 1
XCL DIG 1
XCL DIG 1
XCL DIG 1


A normalization circuit for a phase energization controller receives a rotor position value from a position encoder, and the normalization circuit obtains a normalized rotor position for each phase of a switched reluctance machine. Accordingly, the normalization circuit simplifies the detection of commutation positions for all the machine phases by reducing the commutation position determination to that of a single phase. Also, an initialization circuit for the phase energization controller energizes one or more phases of the switched reluctance motor to set the rotor of the switched reluctance motor to a preferred position to determine an offset value.

The switched reluctance machine is a simple electric machine with no electrical conductors or permanent magnets on the rotating part and only simple, switched coils, often carrying only unidirectional currents, on the stator. This attractive combination of a simple machine, coupled with the rapidly evolving capabilities and falling costs of power-electronic switches and control electronics has led to the continued development of switched reluctance drives.
FIG. 1 shows the principal components of a switched reluctance drive system 10. The input power supply 12 can be either a battery or rectified and filtered mains. The DC voltage provided by power supply 12 is switched across the phase windings of the machine 14 by the power converter 16 under the control of the electronic control unit 18. The switching must be correctly synchronized to the angle of rotation of the rotor for proper operation of the drive 10. As such, a simple rotor position encoder 20 is typically mounted on the machine shaft 22 to supply position signals to the controller 18 for determining the absolute angular position of the rotor. The encoder 20 can also be used to generate a speed feedback signal in the controller 18. FIG. 1 shows this being utilized to give closed-loop speed control.
FIG. 2 shows the elements of a typical four-phase switched reluctance machine 14. The machine 14 has eight salient poles 26a-h on the stator 28 and six poles 30a-f on the rotor 32. Each stator pole 26a-h carries a simple exciting coil 34a-h Opposite coils 34a and 34e, 34b and 34f, 34c and 34g, and 34d and 34h are connected to form the north/south pole pairs for the four "phases." Only one phase circuit 36 is shown for the opposite coils 34a and 34e. The opposite coils 34a and 34e are excited from a dc supply 38 through two switches or transistors (S1 and S2), and two diodes (D1 and D2) allow energy to return to the supply 38. Other switching circuits are well known in the art.
If it is desired to operate the machine as a motor, torque is developed in the machine 14 by the tendency for the magnetic circuit to adopt a configuration of minimum reluctance, i.e., for an opposing pair of rotor poles 30a and 30d, 30b and 30e, and 30c and 30f to be pulled into alignment with an excited pair of stator poles 26a-h, maximizing the inductance of the exciting coils 34a-h. By switching the phases in the appropriate sequence, the rotor 32 will continuously rotate in either direction so that torque is developed continuously in the appropriate direction. Moreover, the larger the current supplied to the coils 34a-h, the greater the torque. Conversely, if it is desired to operate the machine as a generator, the coils are excited as the motor poles move away from the stator poles. Power is then transferred from the shaft of the machine to the electrical supply.
FIG. 3 shows a rotor pole 41 approaching a stator pole 39 according to arrow 35 for the switched reluctance machine 14 of FIG. 2. FIG. 4 shows the phase circuit 47 for opposite coils 40 as partially depicted in FIG. 3. As the rotor pole 41 approaches the stator pole 39, an energization cycle commences for the phase associated with stator pole 39. When leading edge of the rotor pole 41 reaches position 36, represented by absolute rotor angle .THETA.1 ("on angle"), the phase transistors 44 are turned on, and the DC supply 42 is applied to the opposite coils 40, causing flux to build up. Consequently, the stator pole 39 attracts the rotor pole 41, thereby producing torque. When the rotor pole 41 reaches an absolute rotor position 37, represented by absolute rotor angle .THETA.2 ("freewheel angle"), only one transistor 44 is turned off. This causes the current to "freewheel" around the other transistor 44 and leads to an approximately constant-flux condition. When the rotor pole 41 reaches absolute rotor position 38, represented by absolute rotor angle .THETA.3 ("off angle"), both phase transistors 44 are held in the off state, and diodes 46 conduct, placing a voltage of reverse polarity across the winding and causing flux to decay to zero.
The on, freewheel, and off positions discussed above represent typical commutation points in the energization cycle for each phase of a switched reluctance machine. These three angles are controlled by the controller 18 to control the torque. The relationship between the angles and the torque is a nonlinear function of torque and speed. The controller 18 may interpolate from a look-up table of measured settings to obtain and update the proper commutation points for each phase of the switched reluctance machine.
Previous switched reluctance systems used a simple angular position sensor to control the energization of the motor phases. Typically, the sensor gives one pulse per phase for each energization cycle of the motor. The timing markers derived from the sensor are interpolated electronically to obtain adequate resolution. The advantage of this system is the low sensor cost. However, a substantial disadvantage exists with respect to the lack of information provided when running at slow speeds or high acceleration rates.
Absolute position encoders (e.g., resolvers, optical encoders) have been widely used in high performance drive systems for many years, particularly for position control systems. Absolute position encoders give angular resolution sufficient to remove the need for interpolation of angles, but, especially for higher resolution encoders, the absolute position encoders require more hardware, more software, or both to make adequate comparisons between the absolute rotor position and the required commutation points.
For the switched reluctance drive of FIG. 2, each phase undergoes six energization cycles per rotor revolution, one for each rotor pole. Since each energization cycle has three commutation positions (on, off, and freewheel), each phase requires eighteen comparisons between these required positions and the actual rotor position. For four-phase machine, this requires a total of seventy-two such comparisons. Such an arrangement would require seventy-two sets of, e.g., the circuitry of FIG. 5 which uses a twelve-bit resolver word. FIG. 5 includes a twelve-bit latch 49 storing a predetermined absolute rotor position, and a twelve-bit comparator 50 for comparing the predetermined absolute rotor position with the high resolution, absolute rotor position from the position encoder or resolver 48. These techniques are standard and are well known by those skilled in the art. Other implementations would be possible.

Control of a switched reluctance machine


A system for measuring an amount of microroughness of a surface of a substrate, wherein a first beam of electromagnetic radiation and a second beam of electromagnetic radiation are generated, the first and second beams being substantially parallel and spaced apart from each other so that the first and second beams are substantially non-overlapping, and the first and second beams are focused onto the substrate so that the beams impinge upon a selected area of the surface of the substrate having a surface contour, the surface contour of the substrate causing a scattering of both beams. The scattering of the first and second beams is detected, the amount of scattering corresponding to a microroughness value of the selected area of the substrate, and the microroughness value of the selected area of the substrate is determined from the amount of scattering of the first and second beams. The microroughness measuring system may also be used for controlling a fabrication process.

This invention relates generally to a system and method for measuring the roughness of a surface of a substrate, and in particular, to a system and method for measuring the microroughness of a surface of a substrate.
Various types of substrates are used today that require a flat surface. For example, a flat semiconductor substrate is needed to fabricate electrical devices on the substrate so that the devices have the desired properties. A disk drive media substrate also needs to have a flat surface so that data may be magnetically or optically encoded onto the surface of the substrate. Similarly, substrates for liquid crystal flat panel displays also require flat surfaces. As smaller devices are formed on the semiconductor substrate and as more data is encoded on the disc drive media substrate, the surfaces of the respective substrates must have less roughness overall, and the average size of the roughness must be reduced.
For example, as the size of the active devices, such as transistors formed on a semiconductor substrate is reduced, it is necessary to use correspondingly thinner gate dielectrics to separate the substrate from the gate electrode and achieve the desired performance of the transistor. For current 0.18 .mu.m transistor design rules, the gate dielectric must be only 50 angstroms thick. As a comparison, a single strand of human hair is 20,000 times wider than this gate dielectric. However, even through the thickness of these gate dielectric must be reduced, the breakdown voltage strength of these gate dielectrics must be maintained. For a gate voltage of only 2 volts, the gate dielectric must be able to withstand an electric field in excess of 4 megavolts/cm.
To meet these design requirements, it is necessary to minimize the roughness of the semiconductor substrate, especially at the interface between the gate dielectric and the substrate. The roughness at the interface between the gate dielectric and the substrate is known as microroughness because the size of the roughness is on the order of only 1 angstrom. The microroughness is usually characterized by an average size of all of the microroughness particles, known as an RMS value, and a number of microroughness particles that have a particular microroughness size, known as the size density. For a gate dielectric that is 50 angstroms thick, any roughness that is on the order of a few angstroms is not acceptable and must be removed, or the device may not meet its desired performance.
Thus, there is a need for measuring systems that effectively measure and control the microroughness of the surface of the substrate. There are two conventional methods for measuring microroughness. One is an atomic force microscopy (AFM) method in which a microscope moves an atom-sized measuring probe along the surface of the substrate, and the microroughness of the substrate is determined. This method is slow, and requires contact with the surface of the substrate, which is undesirable. Due to these limitations with this method, atomic force microscopy is not well suited for measuring the microroughness of substrates in real time in order to control a fabrication process.
Reflectance scatterometry is another conventional method that involves using a light source to reflect light off of the surface of the substrate, and measuring the scattering that occurs to the light due to the microroughness. From the scattering of the light, the microroughness may be determined. This method does not contact the surface of the substrate and is faster than atomic force microscopy, but requires a large portion of the substrate surface for testing. For real-time control of a fabrication process, only a small area of the substrate is available for testing since the gate dielectric, for example, may be only 0.5 micrometers long. In addition, this method does not have the range of sensitivity necessary to measure microroughness down to the angstrom size roughness level, which is needed for current fabrication processes.
Thus, there is a need for a system and method for real time monitoring and measurement of the microroughness of a surface of a substrate to control a fabrication process which avoid these and other problems of known devices, and it is to this end that the present invention is directed.

System and method for measuring the microroughness of a surface of a substrate


A method for unsupervised image segmentation based on a background likelihood estimation is described herein. The method includes calculating a distance for each pixel in an input image and transforming each distance into a probability of the distance of belonging to a background of an input image or a foreground of the input image. The method also includes transforming each probability into a log likelihood value to form a unary term and minimizing an energy function including the unary term to obtain a set of foreground labels and a set of background labels.

Multiple cameras are used to capture activity in a scene. The multiple cameras may be used to enable volumetric capture in which a scene is captured from a plurality of viewpoints. Segmentation may be used to locate objects and boundaries (lines, curves, etc.) in data obtained from multiple cameras for volumetric capture purposes.
The same numbers are used throughout the disclosure and the figures to reference like components and features. Numbers in the 100 series refer to features originally found in FIG. 1; numbers in the 200 series refer to features originally found in FIG. 2; and so on.

Unsupervised image segmentation based on a background likelihood estimation


A method for enabling a mailer to infer the amount of business reply that he/she is going to receive on a given day and determine the amount of postage that is due. The foregoing is accomplished by placing a planet code that references the mailer's permit number on the business reply so that when a scanner at the USPS reads the planet code, the postage for the business reply will be calculated, and the mailer will be notified of the calculation so that the mailer may deposit sufficient funds in a deposit account to pay for the postage. The mailer may deposit funds in the account by issuing a check, having funds automatically transferred from some account, or automatically having a check issued so that someone may take the check to the USPS and receive the business reply. Thus, the mailer will be able to determine the amount of postage that is going to be charged to his/her account.

Business mailers prepare and process various types of business mail utilizing inserters to collate the sheets and stuff the same into envelopes. Invoices, advertisements for the purchase of goods and/or services, prepaid post cards as well as business reply mail pieces, i.e., business reply envelopes, business reply cards. Business reply mail pieces sometimes are placed in outer envelopes mailed by business mailers to customers. Recipients of business mailers' mail may enclose a check and invoice and/or an advertisement order form in the business reply mail piece and mail it via the United States Postal Service (USPS) to the business mailer. Business mailer recipient customers may also mail the enclosed business reply card back to the business mailer.
The USPS allows a business mailer to receive first class business reply business reply from their customers and pay postage and a fee only for the returned to the mailer from the original distribution of the mailing. Postage and fees are collected when the mailer picks up the business reply mail pieces at his/her local USPS office. The mailer is unaware of how many business reply mail pieces are going to be returned to him/her by his/her customers. For instance, if a mailer mailed one million envelopes containing advertisements with business reply envelopes, the mailer may owe the USPS $9,700.00 if 10,000 business reply mail pieces were returned to the business mailer. If 100,000 business reply mail pieces were delivered to the mailer by the USPS, the mailer would owe the USPS $97,000.00; and if 1,000,000 business reply mail pieces were delivered to the mailer by the USPS, the mailer would owe the USPS $970,000.00.
The USPS has established deposit accounts in which the mailer may deposit money to pay for the business replies that are delivered to the mailer's local USPS office. Since the mailer does not know on a daily basis how many business replies will be delivered to the mailer's local post office, the mailer does not know how much money to keep in his/her deposit account.
Thus, one of the disadvantages of the prior art is that mailers are unaware of the amount of money they are required to place in their deposit accounts on a daily basis; hence, the mailers over fund their deposit accounts, adversely affecting their cash flow.


A pair of semicylindrical magnet segments are secured against the inner surface of a motor shell of a permanent magnet motor by wedging an elastic locking element into each space between the magnets. Each locking element has an enlarged head portion that extends beyond opposite ends of the magnet segments, the lock elements maintaining the magnet segments in position, circumferentially, radially and axially, within the motor shell to form a shell-magnet subassembly. An assembly fixture is used to support and align the elements during their assembly. A motor armature, including a commutator, is inserted within the subassembly, and end caps having bearings and brushes are bolted to respective ends of the motor shell to form a complete motor.

Some previously designed permanent magnet motors had permanent magnets affixed to the inner surfaces of associated motor shells with adhesive substances. The use of adhesives to secure magnets in place can present problems, however. Due to their application and/or curing times and the general mess sometimes attending their storage, handling and application, the use of adhesives can slow the overall process of motor assembly.
Depending on the adhesives used, especially under high ambient temperature and high-vibration conditions, the bonds secured therewith can be less than permanent. If toxic or flammable adhesives are used, there can also be safety problems involving personnel working with, or in the area of, the adhesives. Environmental and disposal problems are also a problematic consideration when such materials are used.
A number of methods have been developed to mount permanent magnets within motor shells without resorting to adhesives. For example, U.S. Pat. No. 5,216,306, to Nakazawa et al., teaches the use of magnet holders that resiliently apply force against one edge of a magnet, forcing the opposite edge against a fixed magnet-supporting piece and the magnet against the inner peripheral surface of an inner cylinder. The magnet holders are held in position, after assembly, by the reaction forces resulting from the resilient forces they exert on the magnets.
U.S. Pat. No. 5,276,375, to Hartel, and No. 5,391,063, to Hantle, are both generally similar to the Nakazawa patent in that they also teach the use of components, in their cases U-shaped springs, that resiliently apply force against one edge of a magnet, forcing the opposite edge against an unyielding magnet-supporting piece.

Method for securing magnets to a permanent magnet motor shell and a motor made therefrom


In one aspect, a method includes performing a fast discovery on a virtual network to obtain objects and attributes necessary to display the objects on a user interface, performing a full discovery on the virtual network after the fast discovery and performing rediscovery regularly on the virtual network after the full discovery comprising updating object data based on changes since the last discovery was performed.

Over time virtual environments have been used increasingly in storage environment and the scale of their deployment has also increased. For example, a virtual environment may include hundreds to thousands of objects. These objects are added, removed or changed over time. It is important for a host connected to the virtual environment to account for these objects.

Performing discovery of a virtual environment


The present invention relates to a continuous method for the preparation of an aromatic carbonate by reacting a dialkyl carbonate and an aromatic hydroxy compound in the presence of a heterogeneous catalyst, and a reaction apparatus for the same. The continuous method comprises the step of reacting dialkyl carbonate and an aromatic hydroxy compound in the presence of the heterogeneous catalyst in a loop-type, catalyst-containing reaction apparatus, wherein a reactor equipped with a filter in which the catalyst is contained is connected with a heat exchanger portion for providing necessary heat during the reaction, reaction solution is circulated between the catalyst-containing portion and heat exchanger via a circulation pump, and by-products can be eliminated via a distillation column connected with the reactor.

(a) Field of the Invention
The present invention relates to a method for preparing an aromatic carbonate and a reaction apparatus for the same, and particularly to a continuous method for preparing an aromatic carbonate using a heterogeneous catalyst and a reaction apparatus for the same.
(b) Description of the Related Art
Aromatic carbonates are used as starting materials in the preparation of several kinds of isocyanates and aromatic polycarbonates that do not use a very toxic phosgene gas, and they are synthesized mostly by the transesterfication of dialkyl carbonates and aromatic hydroxy compounds. In this reaction, typical reactants are dimethyl carbonate and phenol.
However, such transesterfication is a reversible reaction and its equilibrium constant is very small, and consequently the conversion rate after reaction is very low and the reaction rate is quite slow, and thus it has numerous difficulties in being used in commercial production.
Several attempts have been made to solve such problems, including attempting to increase the reaction rate by improving the performance of a reaction catalyst.
U.S. Pat. No. 4,182,726 disclosed a process of using an AlX3 such as AlCl3, UX3, TiX3, VOX3, VX3, ZnX2, FeX3, and SnX3 class reaction catalysts, wherein X refers to halogen group elements. Also, U.S. Pat. No. 4,045,464 disclosed using Ti class compounds such as titanium tetraphenate or Lewis acids.
Further, U.S. Pat. No. 4,552,704 disclosed Ti and Sn class reaction catalysts such as butyltin oxide hydroxide, U.S. Pat. No. 4,554,110 disclosed polymeric tin compounds as reaction catalysts, and U.S. Pat. No. 4,609,501 disclosed a reaction catalyst mixing at least one Lewis acid and at least one protic acid.
These prior arts can be said to try to improve the reaction rate by the action of the reaction catalyst rather than to improve reactivity by the reaction process, in order to increase efficiency in the preparation of DPC (diphenyl carbonate) from DMC (dimethyl carbonate).
However, all of the catalysts proposed in these patents are homogeneous catalysts, and thus when they are used they should be mixed with reactants in a certain ratio. Also, even though reaction by-products such as methanol, which are generated during reaction, were allowed to be continuously eliminated from the reaction system, the reaction rates shown in the examples were not high.
On the other hand, there have been attempts to use heterogeneous catalysts as reaction catalysts. U.S. Pat. No. 5,354,923 employed a stirring reactor using a catalyst in a powdered form having a surface area of not less than 20 m2/g, and U.S. Pat. No. 5,565,605 applied heterogeneous catalysts such as titanoalumino phosphate for reaction.
However, the heterogeneous catalysts prepared hitherto are in a powdered form and they are subject to reaction and separation processes together with the reactants, and thus they cause a problem of being adhered to the inside walls of pipes and equipment. They are also problematic in their re-use after separation because they co-exist with reaction products having a high boiling point.
Further, there have been attempts to increase efficiency in the preparation of DPC by designing unique reaction processes along with the development of reaction catalysts. U.S. Pat. No. 5,210,268 employed a multi-stage distillation column as a reactor, wherein two reactants having different boiling points were counter-currently contacted by injecting the reactant having a high boiling point to the upper portion of the column together with a homogeneous catalyst and by heating and evaporating the reactant having a low boiling point at the bottom portion of the column to synthesize an aromatic carbonate.
Also, U.S. Pat. No. 5,426,207 disclosed a reaction process using three reactors that were connected in series, and U.S. Pat. No. 5,523,451 disclosed a process of applying multiple bubble columns that were connected in series to a reactor. Also, U.S. Pat. No. 6,057,470 disclosed a reaction process using a reaction distillation method.
However, these processes have numerous difficulties in the separation of catalysts because they use homogeneous catalysts or catalysts in a powdered form, and they also have difficulties in economic aspects because a certain amount of catalyst must be continuously supplied to the reaction system in a continuous operation.

Continuous method for preparing aromatic carbonate using a heterogeneous catalyst and a reaction apparatus for the same


A variable damping shock absorber is disclosed. The shock absorber has a two-wire electrical lead extending into the piston rod. The electrical energy provided by the lead drives a drive motor, which rotates in alternating directions depending on the setting of an internal switch that switches upon occurrence of voltage spike, which occurs when the motor has driven an internal rotatable valve as far as the valve can go within the confines of rotation permitted by the valving. The drive motor then drives an internal valve between an open and closed position, which in turn opens and increases, or closes or reduces, a path in fluid flow from one cavity to another as the piston moves within the shock absorber.

This invention relates to dampers, such as shock absorbers or damping struts, for vehicles More particularly, this invention relates to shock absorbers and damping struts in which damping force provided by fluid flow is adjustable either manually or automatically in response to vehicle speed, load, acceleration, or road conditions.
In one typical suspension system for automobiles, shock forces experienced by the suspension system are "absorbed" by a spring and shock absorber combination. The shock absorber consists of a rod and piston mounted within a cylinder, and the spring urges rod to extend outwardly from the outer cylinder Vibrational shock energy within the suspension system is "absorbed" and stored by the compression and extension of the spring. That energy is, in turn, dissipated by the shock absorber or strut during the damping action that results from a valved piston reciprocating within the cylinder containing hydraulic fluid. The damping action converts the vibrational energy to heat which the cylinder wall conducts and transfers to the surrounding atmosphere.
One typical shock absorber has an oil cavity in the cylinder on each side of the rod piston within the cylinder. Compression of the shock absorber (as the spring and piston rod are compressed in response to contact of the wheel with the road) forces oil from one cavity into the other, and rebounding is subsequently damped by the resistance of oil flow in the "reverse direction as the piston is urged toward extension by the rebounding force of the spring. The valving within the piston and between the cavities thus provides the appropriate resistance to fluid flow between the two cavities.
For example, various types of check valves and variable flow restrictions have been developed to allow fluid flow in compression (from the cavity beneath the piston through or around the piston head and into the outer cylinder reservoir cavity) more freely, i.e., with less resistance, than in extension (from the outer reservoir cavity, and from the cavity surrounding the rod into the cavity beneath the piston). Such check valves thus provide greater damping when desired, during extension (rebound), rather than during compression shock absorption, when the shock absorber should compress relatively freely to minimize energy transfer to vehicle occupants.
Improvements on this basic arrangement have provided varying damping characteristics for varying road conditions or vehicle speed, load, or acceleration. As a vehicle goes faster, for example, the damping should often be increased to counteract the increased forces that tend to reduce contact between the tire and the surface of the road.
One such variable damping shock absorber is shown in U.S. Pat. No. 4,527,676 issued Jul. 9, 1985 to Emura et al. The Emura patent discloses a shock absorber with variable damping accomplished by a motor rotating a four-way check valve in the shock. The motor is either (1) a step motor with four steps, one for each of the possible orientations of a four-way check valve, or (2) a feedback-controlled motor, with four arcuate electrical leads contacted by brushes to determine the exact position of the motor drive. Both types of motors are relatively complicated and expensive, as is the four-way valving associated with each.
For example, the Emura device requires a four-wire harness. This results in an expensive and complicated vehicle harness.
Another problem with the Emura device is its relatively complicated and expensive motor mechanism In the embodiment utilizing a four-way step motor, such motors are inherently complicated and expensive because they must be adapted to stop at each of four points, with appropriate electronics to maintain control of the position of the step motor at each of its four stop positions.
In Emura's embodiment utilizing a feedback-controlled motor, the motor provides four-way stepping through a feedback control circuit which receives the feedback from mechanical wipers brushing over electrical contacts. These wipers and contacts wear and corrode over time, causing loss of electrical contact. Emura's variable damping mechanism can thus completely fail long before likely breakdown from any of the remaining components.


An aerodynamic noise measurement system for a vehicle uses sound reflectors to determine the sound wave propagation of aerodynamic noise of the vehicle. The vehicle is placed within a test section of a wind tunnel. The air flow of the wind tunnel generates the aerodynamic noise as it passes over the vehicle. An array of sound reflectors is placed outside of the air flow of the wind tunnel. Microphone arrays receive the aerodynamic noise directly from the source and from the sound reflectors. An analyzer system forms an acoustic image of the vehicle based on the aerodynamic noise. A viewing device displays an image of the vehicle with an overlay of aerodynamic noise data in real-time.

Engine noise, road noise, and aerodynamic noise are the primary sources of noise caused by a vehicle. As current efforts continue to decrease the engine and road noise, the relative contribution to noise from aerodynamic noise is increasing. Therefore, the aerodynamic noise must be reduced in order to reduce the overall amount of noise experienced in the vehicle or outside of the vehicle.
In order to determine the causes of aerodynamic noise from the vehicle, the aerodynamic noise from various point sources on the vehicle must be measured. A conventional method for measuring the aerodynamic noise uses an array of microphones stationed inside or outside the airstream at a fixed distance from the vehicle. However, limits on microphone size and geometry, as well as processing time, limit the effectiveness of this method. The microphone array also generates its own noise, which interferes with the measurement of the aerodynamic noise.

Aerodynamic noise source measurement system for a motor vehicle


A method of generating language model statistics for a new word added to a language model incorporating at least one class file containing contextually related words. The method can include the following steps: First, language model statistics can be computed based on references to at least one incorporated class file. Second, a new word can be substituted for each reference to a selected class file. Additionally, the language model statistics can be re-computed based on the new word having been substituted for the reference. Third, the re-computed language model statistics can be displayed in a user interface and modifications can be accepted to the re-computed language model statistics through the user interface. Fourth, the language model statistics can be further re-computed based on the modifications. In consequence, the language model statistics are re-computed for the new word without introducing contextual inaccuracies in the language model.

1. Technical Field
The present invention relates to the field of speech recognition software and more particularly to a method of augmenting a language model for a speech recognition vocabulary.
2. Description of the Related Art
Speech recognition is the process by which acoustic signals, received via a microphone, are "recognized" and converted into words by a computer. These recognized words may then be used in a variety of computer software applications. For example, speech recognition may be used to input data, prepare documents and control the operation of software applications. Speech recognition systems programmed or trained to the diction and inflection of a single person can successfully recognize the vast majority of words spoken by that person.
In operation, speech recognition systems can model and classify acoustic signals to form acoustic models, which are representations of basic linguistic units referred to as phonemes. Upon receipt of the acoustic signal, the speech recognition system can analyze the acoustic signal, identify a series of acoustic models within the acoustic signal and derive a list of potential word candidates for the given series of acoustic models. Subsequently, the speech recognition system can contextually analyze the potential word candidates using a language model as a guide.
The task of the language model is to express restrictions imposed on the manner in which words can be combined to form sentences. The language model can express the likelihood of a word appearing immediately adjacent to another word or words. Language models used within speech recognition systems typically are statistical models. Examples of well-known language models suitable for use in speech recognition systems include uniform language models, finite state language models, grammar based language models, and m-gram language models. Statistically, in an m-gram language model, all word sequences are deemed possible. As a result, in an m-gram language model, the probability of a word having been uttered by a speaker can be based only upon the (m−1) immediate predecessor words. Typical m-gram language models can include the unigram (m=1), bigram (m=2) and trigram (m=3) language models.
Trigram language models are formed by constructing all possible three word permutations for each word in a large corpus of text typically referred to as a training corpus. Subsequently, the frequency of each trigram appearing in the training corpus can be observed. Unigrams, bigrams, and trigrams appearing in the training corpus can be assigned the corresponding frequency values, appropriately discounted to leave some probability space for unseen bigrams and trigrams. The resulting collection of unigrams, bigrams and trigrams and their corresponding frequency values (language model statistics) form the trigram language model.
After a speech recognition vocabulary with its associated language model statistics has been created, there will arise a need to add new words. A language model developer might need to add new words when refining the speech recognition vocabulary or when building an extension to the vocabulary. An end-user of a speech recognition system might need to add his or her own personal words to the vocabulary. Hence, the needed language model statistics must be generated for each additional new word prior to adding the additional words to the speech recognition system vocabulary. However, in order to add a new word lacking language model statistics to a speech recognition system, a new training corpus containing therein the additional words must be analyzed to develop unigrams, bigrams, trigrams, and frequency data for the additional words.
Alternatively, a language model developer might edit a speech-dictated document to include the additional words by manually inserting each additional new word in a context-relevant location of the speech-dictated document. Although this alternative approach can produce adequate results when editing a small file or a small number of files, the process can become cumbersome when developing specialized speech recognition vocabularies for specialized topics such as medicine, law and travel. Such specialized topics implicate the modification of thousands of files. Moreover, typically those files exceed in size the maximum capacity of a conventional text editor.
It is sometimes possible to obtain language model statistics for a new word from contextually-related words or classes of words in the existing speech recognition vocabulary. For example, if the word "Midway", a reference the airport located in Chicago, Ill., is to be added to the speech recognition vocabulary, language model statistics must be developed for this additional new word. However, rather than developing completely new statistical information for the additional word, the language model statistics for "Midway" can be based upon existing language model statistics for the existing word "Heathrow" in reference to the airport located in London, England.
Present methods of adding new words to a speech recognition system by an end-user include (1) correction in a speech-dictated document or (2) analysis of user-supplied sample documents. The language model statistics generated in these two methods are limited. Adding a new word during correction will only yield one sample context for the new word. The contextual coverage attained by adding new words from sample documents depends on the amount of text present in the user-supplied documents. The number of documents typically supplied for analysis tends to be small and, therefore, leads to very few sample contexts for the new words. Finally, users might well want to simply add new words to the vocabulary in isolation without any accompanying context, especially if that user is a specialist in a field for which there are no specific language models (or topics) to purchase to extend the vocabulary.
Present methods of adding additional words to speech recognition systems based upon existing language model statistics utilize class files. Class files allow a language model developer to generate a file containing words having similar contextual properties. An example of a class file includes a list of airport names. Once created, the class file itself can be referred to in the language model in lieu of each component word contained in the class file. For example, if the class file "airport.cls" contained as constituent components, "O'Hare", "Heathrow", and "Midway", all instances of those specific airport names in the language model can be substituted with a generic reference to the class file "airport.cls". As such, the trigram "Heathrow in England" would be modified to "[airport.cls] in England".
Developers of speech recognition vocabularies, developers of speech vocabulary extensions (e.g., specialized topics) and end-users can benefit from methods that use class files to generate statistics for new words. However, new words cannot be blindly added to classes because this will often lead to contextual inaccuracies. For example, if 'Midway' were added to the airport class, from the perspective of the language model, 'Midway' in combination with 'in Chicago' can remain as likely a word sequence as 'Midway' in combination with 'in England'—an absurdity. Thus, there has arisen a need for a better way to ensure contextual accuracy when adding additional new vocabulary words to a speech recognition system.

Method for preserving contextual accuracy in an extendible speech recognition language model

International Business Machines Corporation


A method for manufacturing a honeycomb structured body including molding ceramic raw material to form a pillar-shaped honeycomb molded body having a multiplicity of cells disposed in parallel with one another in the longitudinal direction with a cell wall therebetween, and filling in either one of the end portions of each of the cells with a plug material paste, and firing the honeycomb molded body to manufacture a honeycomb structured body comprising a honeycomb fired body, wherein after having filled in either one of the end portions of each of the cells of the honeycomb molded body with the plug material paste, a plug material paste drying process to dry the plug material paste is conducted by blowing hot air to an end face of the honeycomb molded body using a hot air drying apparatus.

1. Field of the Invention
The present invention relates to a method for manufacturing a honeycomb structured body.
2. Discussion of the Background
Particulates such as soot and the like contained in the exhaust gas expelled by the internal combustion engines of vehicles such as busses, trucks and the like, and construction equipment, have become a problem of recent, in that they cause harm to the environment and the human body. To remedy this, there are currently being proposed numerous kinds of honeycomb filters using a honeycomb structured body of porous ceramic as a filter for capturing particulates contained in exhaust gasses, and thus purifying the exhaust gas.
Conventionally, when manufacturing a honeycomb structured body, for example, first, a ceramic powder, a binder, and a liquid dispersal medium are combined to prepare a wet mixture. Then, this wet mixture is further mixed using a screw mixer and the like, and furthermore, the wet mixture is continuously extrusion-molded with a die, and the extruded molded body is then cut to a prescribed length to manufacture a rectangular pillar-shaped honeycomb molded body.
Next, the honeycomb molded body attained above is dried using a microwave drying apparatus or a hot air drying apparatus to thereby (for example, see JP-A 2000-44326, JP-A 2005-131800) manufacture a dried honeycomb molded body having a consistent degree of strength and easy handleability.
After this drying process, a plug material paste layer is formed by filling in either one of the end portions of each of the cells of the honeycomb molded body with the plug material paste to achieve a sealed state of the cells. After the sealed state has been achieved, degreasing and firing treatment is carried out thereto, thus manufacturing the honeycomb fired body.
After this, a sealing material paste is applied onto the sides of the honeycomb fired bodies, and the honeycomb fired bodies are adhered together using a sealing material paste. This state of a multitude of honeycomb fired bodies being bonded by interposing a sealing material layer (adhesive layer) effectuates an aggregated body of honeycomb fired bodies. A cutting process is then carried out on the achieved aggregate body of honeycomb fired bodies using a cutting machine or the like to form a ceramic block of a prescribed form, such as a cylindrical form, a cylindroid form, and the like. Finally, a sealing material paste is applied over the outer periphery of the ceramic block to form a sealing material layer (coat layer), thus completing the manufacturing of the honeycomb structured body.
The contents of JP-A 2000-44326 and JP-A 2005-131800 are incorporated herein by reference in their entirety.

Method for manufacturing a honeycomb structured body


A personal datacenter system is described herein that provides a framework for leveraging multiple heterogeneous computers in a dynamically changing environment together as an ad-hoc cluster for performing parallel processing of various tasks. A home environment is much more heterogeneous and dynamic than a typical datacenter, and typical datacenter scheduling strategies do not work well for these types of small clusters. Machines in a home are likely to be powered on and off, be removed and taken elsewhere, and be connected by an ad-hoc network topology with a mix of wired and wireless technologies. The personal data center system provides components to overcome these differences. The system identifies a dynamically available set of machines, characterizes their performance, discovers the network topology, and monitors the available communications bandwidth between machines. This information is then used to compute an efficient execution plan for data-parallel and/or High Performance Computing (HPC)-style applications.

It is increasingly common for households to own more than one computer, and for these machines to be on a home network. Each of these computers has a substantial amount of computing power, memory, and storage capacity. Current popular operating systems allow you to use the resources of the local machine very easily, but it is difficult to make use of the resources of other machines on the network. Hence, when running a compute-intensive application the CPUs of remote machines are typically idle, and their memory is not accessible. Similarly, when running an I/O intensive application the local disk may be 100% utilized, but other storage devices are idle.
Home computational needs are increasing. For example, video editing and transcoding is increasingly common and can take hours to complete. Even with a high-end home computing system, tasks can take a long time to complete. On the other hand, most homes have multiple computers in the form of desktops, laptops, home theater PCs (HTPCs), as well as non-traditional computing devices that contain common computing hardware such as game consoles, mobile phones, and embedded devices (e.g., set top boxes, routers, and other equipment).
In datacenter settings, distributed systems software makes it possible to spread data across multiple storage devices, and to run computations in a parallel fashion across multiple machines. Data centers are often very homogeneous, meaning that each machine has a similar processor, amount of memory, network bandwidth, and other resources. Scheduling algorithms used in datacenters are typically greedy and do not consider machine differences, but rather quantity and availability of machines when scheduling. Various companies provide data-parallel frameworks for spreading job execution to multiple computers in data centers, such as MICROSOFT™ Dryad, Google MapReduce, and Yahoo! Hadoop. Some of these also provide toolsets and programming languages to make parallel computing easier, such as MICROSOFT™ DryadLINQ.
Similar functionality is increasingly useful in a home/personal setting, but much more complex due to issues of heterogeneity, connectivity, power management, and software version/update management. Assumptions that are valid in data centers completely fail in home environments. For example, home computers may come and go as a user takes a laptop or other mobile device into and out of the house. Home computers may use a variety of connection types for networking, such as a Wi-Fi connection when a user is roaming around the house and a wired Ethernet connection when the user docks a laptop. Home computers may also go to sleep or run out of battery power. Finally, home computers include a mish-mash of processors, graphical processing capabilities, memory quantity, disk space, disk speed, and so forth. These differences contribute to distributed computing being virtually non-existent in the home or other small cluster settings.

Scheduling and management in a personal datacenter


A dry etching method by a plasma etching forms a mask pattern, having an opening up to 1 .mu.m width on a silicon oxide layer formed on a silicon substrate. The substrate is laced into a reactive chamber having an etching gas introducing means and fluorocarbon gas and hydrogen gas as the etching gas are introduced such that a ratio of the hydrogen gas to the gas mixture satisfies 50% to 80%. The plasma is generated, and by using the plasma etching, the silicon oxide layer is etched according to the mask pattern to form an opening having an aspect ratio of more than 1 in the silicon oxide layer.

1. Field of the Invention
The present invention relates to a dry etching method, and more particularly, to a reactive ion etching (RIE) method.
2. Description of the Related Art
The RIE method conventionally is used as a dry etching method for various materials. In manufacturing a semiconductor device, for example, the RIE method is used for etching a material of an electrode, such as a polysilicon or an SiO.sub.2 layer. The RIE method is used because it can form a very accurate pattern in materials used in manufacturing semiconductor devices.
The RIE method is performed as described below. First, a substrate having a layer to be etched thereon is placed in a vacuum chamber having a pair of parallel plate electrodes. Second, an etching gas that will etch the layer but not the substrate is introduced into the chamber. The etching gas is discharged by applying a high frequency electric power to the parallel electrodes. As a result, the layer is etched by a gas plasma generated from the discharged gas.
Besides the RIE method, a plasma etching method, an Electron Cycrotron Resonance (ECR) type dry etching, an ion beam etching method, and a photo excited etching method are known as dry etching methods. These etching methods are similar to the RIE method with regard to chemically or physically etching the etching materials. In these etching methods, a gas containing fluorine and carbon elements, such as C.sub.2 F.sub.6, CF.sub.4, or CHF.sub.3 are used for etching a silicon oxide layer.
According to the following steps, etching of an SiO.sub.2 layer is performed and a contact hole is formed for connecting electrodes or wires in a semiconductor device such as a dynamic RAM (DRAM). If CHF.sub.3 gas is used as an etching gas to etch a contact hole or a via hole in an SiO.sub.2 layer on an Si substrate, CF.sub.3 radicals (CF.sub.3) are absorbed on the surface of the SiO.sub.2 layer. The CF.sub.3 absorbed on the surface are dissociated into C and F by an ion attack. As a result, C reacts with O in the SiO.sub.2 layer to form CO gas and F reacts with Si in the SiO.sub.2 layer form SiF.sub.4 gas.
The F contained in the CF.sub.3 absorbed on the surface of the Si substrate is extracted by H to form CF.sub.x (x=0, 1, 2, 3) as a polymer. The CF.sub.x polymers function to suppress the etching of the Si substrate. Accordingly, the selective etching of SiO.sub.2 to the Si substrate can be achieved
As the integration of a semiconductor device or circuit is increased, a high selectivity of SiO.sub.2 etching to Si is required. Moreover, as the etching pattern size becomes miniaturized according to the increase of integration formation of a contact hole having a small width and a large aspect ratio, which is the ratio of hole depth to hole width, also is necessary. Unfortunately, the conventional etching methods have not been able to accurately etch high integration patterns.
One method to improve selectivity of SiO.sub.2 to Si using CF.sub.4 and H.sub.2 as an etching gas was presented in "Selective Etching of Silicon Dioxide Using Reactive Ion Etching and CF.sub.4 -H.sub.2 ", L. M. Ephrath, J. Electrochem. Soc., Vol. 124, No. 284, 1977. This RIE method was performed under conditions described below. A 150 W of a high frequency electric power was supplied to parallel plate electrodes provided in the etching chamber. A 40 m Torr of pressure and a 20 sccm (standard cubic centimeter per minute) of CF.sub.4 gas was introduced into the chamber. The H.sub.2 gas flow was changed and a gas mixture rate of CF.sub.4 and H.sub.2 was used to measure the etching rate of SiO.sub.2 and Si.
The result of the measurement is shown in a graph of FIG. 14. As is apparent from FIG. 14, with an increasing of H2 gas flow being introduced, an etching rate of SiO.sub.2 shown by curve a increased and an etching rate of Si shown by curve b decreased. Therefore, the selectivity of SiO.sub.2 to Si was improved with the increase of H.sub.2.
However, when more H.sub.2 was introduced into the chamber, the etching of SiO.sub.2 stopped. This occurred at a 18 sccm of H.sub.2 gas flow, or when a mixture ratio of H.sub.2 to the gas mixture CF.sub.4 was about 47% because a polymer was formed on the surface of SiO.sub.2 and Si. Therefore, according to this etching method, the gas mixture ratio of CF.sub.4 and H.sub.2, which can achieve enough selectivity, is very small. Moreover, the etching rate of SiO.sub.2, or the selectivity, was decreased even with a small change in the gas mixture ratio. Therefore, it is very difficult to practically use this etching method.
An etching method having a large selectivity of SiO.sub.2 to Si, by setting a pressure in a chamber less than 10.sup.-2 Torr, was disclosed in Electro Communication Society, SSP 79-69, p55, 1981. The conditions of this etching method were a 7-8 m Torr of etching gas pressure, a 20 sccm of CF.sub.4 gas flow, and a changing H.sub.2 flow so as to change the mixture ratio of CF.sub.4 and H.sub.2. The etching was made and the etching rate of SiO.sub.2 and Si was measured as shown in FIG. 15. As is apparent from FIG. 15, if the H.sub.2 gas is increased such that a mixture ratio of H.sub.2 to the gas mixture of CF.sub.4 and H.sub.2 is 70%-100%, a high selective etching of SiO.sub.2 to Si can be achieved.
However, in the conventional RIE method of etching SiO.sub.2, if the selectivity of SiO.sub.2 to Si becomes more than 30, the etching ratio in forming a small opening contact hole is rapidly decreased. This phenomenon is generally known as a micro-loading effect. The result of this phenomenon is that, if the etching is continued to form the small contact hole completely, another portion of the substrate on which a large contact hole is formed would be etched so as to also etch the underlying Si substrate.
Moreover, if a contact hole has a small opening and has a large aspect ratio, it is difficult to accurately form the small contact hole.


An apparatus for manufacturing a semiconductor device is disclosed which comprises a chamber which holds a to-be-processed substrate having a film containing at least one kind of metal element which will become a component of a volatile metal compound, a heater which heats the substrate held in the chamber, and an adsorbent which is provided in the chamber and which adsorbs the volatile metal compound generated from the film by heating the substrate.

1. Field of the Invention
The present invention relates to a thermal treatment process in the manufacturing process of semiconductor devices. In particular, the present invention relates to apparatus and method for manufacturing a semiconductor device, which are applied to a heating process when forming electrodes of FeRAM capacitor devices using metal oxide.
2. Description of the Related Art
For instance, in one kind of semiconductor devices, that is, FeRAM (Ferroelectric Random Access Read Memory), the insulating film of capacitor device is formed using oxide ferroelectric material film in order to achieve the number of 1012 rewritable times or more. For example, PZT (Pb—Zr—Ti—O) is given as the above oxide ferroelectric material film. In addition, in the FeRAM, the electrode of the capacitor device is formed using metal oxide conductor in order to prevent the degradation of electrical characteristics of the oxide ferroelectric material film. For example, SRO (SrRuO3) is given as the above metal oxide conductor. The SRO is crystallized, thereby having conductivity. In order to crystallize the SRO, heat treatment process is required when forming SRO electrode.
However, one component of the SRO, that is, Ru is easy to generate a volatile substance, that is, RuO4 in the heat treatment process of the SRO electrode. The generated RuO4 is decomposed after adhering to the surface of the SRO electrode (SRO film); as a result, RuOX crystal particles (abnormal particles) are generated on the surface of the SRO film, as shown in FIG. 4. The above RuOX crystal particles have a diameter of about 0.5 μm or more. For this reason, it is almost impossible to remove the RuOX crystal particles from the SRO electrode by after-cleaning. As a result, the RuOX crystal particles on the SRO electrode has a possibility of causing the operation failure of the capacitor. In addition, the RuOX crystal particles have a possibility of reducing semiconductor device performance, quality and reliability. Consequently, the RuOX crystal particles are a factor of reducing semiconductor device yield, and thus, increasing the manufacturing cost of semiconductor devices.

Apparatus and method for heat treating thin film


An air flow accelerator for creating an air current. The air flow accelerator comprises an air inlet, an air outlet, an impeller, and a motor for rotating the impeller to create an air flow passing from the air inlet to the air outlet. The air outlet comprises a first elongate plenum having an interior passage for receiving the air flow, and a second elongate plenum connected to the first elongate plenum by a common wall between the first elongate plenum and the second elongate plenum. The common wall has a plurality of apertures therein. The second elongate plenum comprises a plurality of chambers such that one or more of the apertures connects to each of the chambers. The second elongate plenum further comprises a narrow slot for emitting the air flow. The air flow emitting from the slot forms a jet inducing a flow of air from outside the air flow accelerator.

Embodiments herein generally relate to fluid flow amplifiers, and in particular to a device that can be installed on a louvered cabinet to increase the volume of air provided to the cabinet.
Traditional methods of electronics cooling within photocopiers, and the like, rely on either passive (heat sink and buoyancy) or active (forced airflow using fans or blowers) methods. With the extended enterprise model of module supply, each supplier is responsible for the effective operation of their sub-system. When combining several distributed electronics modules into one zone within a machine there is a tendency to miss the opportunity to combine the cooling function, each module sticking with its own cooling strategy. This may result in a number of fans, all creating noise and using power, with reducing Ecolabel limits for both parameters, this is becoming a greater concern.
There remains a need for a new and useful air cooling device that avoids or minimizes the disadvantages of multiple fans and blowers. The embodiments herein provide such a new and useful device.


The invention provides methods of using protein trans-splicing for the production of bispecific molecule which has a first antigen recognition portion that binds a C3b-like receptor and a second antigen recognition portion that binds an antigenic molecule present in the circulatory system of a mammal. The invention also provides bispecific molecules produced by protein trans-splicing. The bispecific molecules of the invention can be used for the clearance of pathogenic antigenic molecules from the circulatory system of a mammal. The invention further provides methods of using protein trans-splicing for the production of polyclonal libraries of bispecific molecules, which comprise populations of bispecific molecules with different antigen recognition specificities. Such polyclonal libraries of bispecific molecules can be used for targeting multiple epitopes of a pathogenic antigenic molecule and/or multiple variants of a pathogenic antigenic molecule.

Primate erythrocytes, or red blood cells (RBC's), play an essential role in the clearance of antigens from the circulatory system. The formation of an immune complex in the circulatory system activates the complement factor C3 in primates and leads to the binding of C3 to the immune complex. The C3/immune complex then binds to the type 1 complement receptor (CR1), a C3 receptor, expressed on the surface of erythrocytes via the C3 molecule attached to the immune complex. The immune complex is then chaperoned by the erythrocyte to the reticuloendothelial system (RES) in the liver and spleen for neutralization. The RES cells, most notably the fixed-tissue macrophages in the liver called Kupffer cells, recognize the C3/immune complex and break this complex from the RBC by severing the C3 receptor-RBC junction, producing a liberated erythrocyte and a C3/immune complex which is then engulfed by the Kupffer cells and is completely destroyed within subcellular organelles of the Kupffer cells. This pathogen clearance process, however, is complement-dependent, i.e., confined to immune complexes recognized by the C3 receptor, and is ineffective in removing immune complexes which are not recognized by the C3 receptor.
Taylor et al. have discovered a complement independent method of removing pathogens from the circulatory system. Taylor et al. have shown that chemical crosslinking of a first monoclonal antibody (mAb) specific to a primate C3 receptor to a second monoclonal antibody specific to a pathogenic antigenic molecule creates a bispecific heteropolymeric antibody which offers a mechanism for binding a pathogenic antigenic molecule to a primate's C3 receptor without complement activation. (U.S. Pat. Nos. 5,487,890; 5,470,570; and 5,879,679). It is found that the Fc portion of the mAb specific to C3 receptor plays an important role in the transfer of the erythrocyte-immune complex to an acceptor cell and the subsequent proteolysis of the erythrocyte-immune complex (Nardin et al., 1999, Molecular Immunology 36:827-835). Taylor et al. have shown that this complement-independent process can remove over 99% of pathogens from the circulation as compared to about 10-15% by the normal, complement-dependent, process.
The Taylor method, however, has certain shortcomings. Firstly, the chemistry of the cross-linking reaction is not very efficient. Typically, the yields of such chemical cross-linking reactions are only about 10% to 20%. As a result, a significant amount of purified mAbs or pathogen-binding moieties is lost during the chemical cross-linking step of the manufacturing process. For example, using standard chemical cross-linking agents (such as Pierce's SATA and sulfo-SMCC), 1 mg of pure mAb1 cross-linked to 1 mg of pure mAb2 will generate only between 0.2 to 0.4 mg of pure product mAb1 X mAb2. Secondly, the bispecific molecule produced by chemical cross-linking contains a chemical cross-linker fragment which can be immunogenic. The immunogenicity of the cross-linker can be disadvantageous when re-administering Taylor's bispecific molecule to the same individual because the individual will generate an immune response against the cross-linker moiety and, upon re-exposure of the same individual to another dose of the bispecific molecule, the individual might mount a vigorous immune response against it, reducing potential therapeutic benefits that the bispecific molecule would otherwise provide. Thirdly, the cross-linking process described in the Taylor patents is not site-specific, and consequently, may decrease somewhat the functionality of the mAbs or pathogen recognition domains. Therefore, there is a need for a more efficient method for the production of bispecific molecules.
Protein splicing is a post-translational protein processing reaction that involves the excision of an intervening sequence, the internal protein domain or intein, from a precursor molecule and the concomitant ligation of the two flanking sequences, the N- and C-terminal external protein domains or N- and C-exteins, to form a functional new protein (see, for example, Paulus, 1998, Chem. Soc. Rev. 27:375-386). The excision and ligation are catalyzed by the amino acid residues within an intein plus the first residue at the N-terminus of the C-extein. The residues responsible for splicing are the approximately 100 amino acids at the intein N-terminus and the approximately 35 amino acids at the intein C-terminus (Lew et al., 1998, J. Biol. Chem. 273:15887-15890; Noren et al., 2000, Angew. Chem. Int. Ed. 39:450-466). A typical protein splicing reaction involves 4 nucleophilic displacements by the 3 conserved splice junction residues: a cysteine (Cys), serine (Ser), or threonine (Thr) at the intein N-terminus, an asparagine (Asn) at the intein C-terminus, and a Cys, Ser, or Thr at the downstream C-extein N-terminus (Perle et al., 1997, Nucleic Acids Res. 25:1087-1093; Southworth et al., 1998, EMBO J. 17:918-926). Other intein residues may also assist in the nucleophilic displacement (Perle et al., 1997, Nucleic Acids Res. 25:1087-1093; Southworth et al. 1998, EMBO J. 17:918-926). Protein splicing has been identified in a variety of species, including eucarya, eubacteria, and archaebacteria.
Inteins may also be split into N-terminal and C-terminal intein fragments that can reconstitute and undergo protein trans-splicing. A naturally occurring split intein system encoded in the DnaE gene of Synechocystis sp. PCC6803 (Ssp) was identified (Wu et al., 1998, Proc. Natl. Acad. Sci. USA 95:9226-9231). This split intein system was expressed in E. coli and was shown to exhibit trans-splicing activity in E. coli cells (Wu et al., 1998, Proc. Natl. Acad. Sci. USA 95:9226-9231). More recently, the Ssp DnaE split intein system has also been shown to mediate efficient in vivo and in vitro trans-splicing and cis-splicing in a foreign extein content (Evans et al., 2000, J. Biol. Chem. 275:9091-9094). Engineered split intein systems based on naturally occurring non-split intein systems have also been demonstrated, including the in vitro trans-splicing systems using purified N- and C-terminal fragments of the Mycobacterium tuberculosis (Mtu) RecA intein and the Pyrococcus sp. (Psp) Pol-1 intein (Mills et al., 1998, Proc. Natl. Acad. Sci. USA 95:3543-3548; Lew et al., 1998, J. Biol. Chem. 273:15887-15890; Southworth et al., 1998, EMBO J. 17:918-926). It is shown that the N- and C-terminal fragments of the Mtu RecA intein system can be reconstituted as an inactive disulfide-linked complex of the two intein fragments, which can subsequently undergo trans-splicing reaction by reduction of the disulfide bond.
Inteins and split inteins may also be modified for more efficient and/or controllable splicing and trans-splicing reactions. For example, splicing in chimeric precursors is usually less efficient than in native precursors, presumably due to impaired intein folding in a foreign extein content as evidenced by their temperature-dependent reactivity. (Noren et al., 2000, Angew. Chem. Int. Ed. 39:450-466) Evans et al. show that inclusion of 3 to 5 native extein residues in the N- and C-inteins of Ssp DnaE system may enhance trans-splicing and cis-splicing in a foreign extein content (Evans et al., 2000, J. Biol. Chem. 275:9091-9094). Alternatively, it may be desirable to choose exteins comprising proximal amino acid sequences that are similar to the native exteins. The inteins themselves may also be modified. For example, it is shown that splicing proficiency in E coli is increased when the proline residue adjacent to the N-terminal Cys in the ribonucleoside diphosphate reductase gene of Methanobacterium thermoautotrophicum is replaced with an alanine residue (Evans et al., 1999, J. Biol. Chem. 274:3923-3926). Inteins have also been modified by site-directed mutagenesis so that splicing reactions can be controlled by photochemistry (Cook et al., 1995, Angew. Chem. 107:1736-1737; Cook et al., 1995, Angew. Chem. Int. Ed. Engl. 34:1629-1630; Noren et al., 1989, Science 244:182-188).
Means for fusing proteins and/or synthetic polypeptides based on protein splicing and trans-splicing have been reported (see, for example, Evans et al., 1999, Biopolymer 51:333-341; Evans et al., 1999, J. Biol. Chem. 274:3923-3926; Evans et al., 1999, J. Biol. Chem. 274:18359-18363). In vitro trans-splicing generally offers a more controlled means in utilizing protein splicing in protein synthesis. Reconstitution and trans-splicing in vitro also allows ligation of exteins expressed in different cells. This has also allowed expression of proteins that are otherwise not possible in a single cell (Noren et al., 2000, Angew. Chem. Int. Ed. 39:450-466). On the other hand, in vivo trans-splicing may be more efficient in that the co-expressed inteins may be less prone to misfolding, due both to more efficient reconstitution and/or the assistance of the powerful protein folding machinery present in a cell (Southworth et al., 1998, EMBO J. 17:918-926).
Discussion or citation of a reference herein shall not be construed as an admission that such reference is prior art to the present invention.

Method of producing bispecific molecules by protein trans-splicing