A solar cell is composed of a semiconductive material having an active zone in which charge carriers are produced by photons which strike and penetrate into the solar cell. The cell is comprised of a semiconductive body having an electrically insulating laminate with metal contacts therein positioned on the semiconductor body in the active zone thereof. The insulating laminate is composed of a double layer of insulating material, with the layer in direct contact with the semiconductive surface being composed of SiO.sub.2 which is either natural or is produced at temperatures below 800.degree. C. and the layer superimposed above the SiO.sub.2 layer being composed of a different insulating material, such as plasma-produced Si.sub.3 N.sub.4. In certain embodiments of the invention, a whole-area pn-junction is provided parallel to the semiconductive surface. The solar cells of the invention exhibit a higher degree of efficiency due to a higher fixed interface charged density, and low surface recombination velocity, an increased UV sensitivity, improved surface protection and passivation and improved anti-reflection characteristics relative to prior art solar cell devices.

1. Field of the Invention
The invention relates to semiconductive solar cells and somewhat more particularly to solar cells composed of semiconductive materials having an active zone provided with an electric insulating coating with metal contacts therein so that charge carriers are produced in the active zone via energy striking and penetrating into such cell.
2. Prior Art
As an alternative to conventional solar cells having a flat pn-junction parallel to a semiconductor surface, the so-called MIS solar cell (metal-insulator-semiconductor) is known. In such devices, pairs of electron holes produced by the light energy are separated in an electric field of a Schottky contact, where metal and semiconductor are separated by a thin insulating layer (having a thickness of less than 5 nm). In instances where the semiconductive material is silicon, the thin insulating layer is a SiO.sub.2 layer. In comparison to normal Schottky contact solar cells, this oxide layer, through which electrons can tunnel, is characterized by a higher open-circuit under illumination without substantial increase in the series resistance of the cell. A MIS solar cell of this kind is disclosed for example, in an article by R. J. Stirn and Y. C. M. Yeh in "Applied Physics Letters," Vol. 27, No. 2, July 7, 1975, pages 95-98.
Advantages of such MIS solar cells, in comparison with conventional pn-cells include:
(a) no high-temperature manufacturing steps and thus lower production costs, in comparison with pn-cells;
(b) no crystal structure defects resulting from diffusion, which structures can act as recombination centers and can thus substantially reduce the efficiency of a device;
(c) higher efficiencies can be achieved for short wavelengths (UV) since the electric field extends to the semiconductor surface and consequently the absorption of the UV-light occurs in a zone of high field strength;
(d) a high radiation resistance;
(e) more adaptable for use of polycrystalline and amorphous semiconductive materials so that cheaper devices are attained.
However, difficulties are achieved in producing a uniform large-area MIS contact, including the required extremely thin light-permeable metal layer.
Another alternative in attaining relatively cheap solar cells which at least partially avoids the above mentioned difficulties, consists in using a so-called inversion layer solar cell. In such devices, the charge carriers are accumulated by using a conductor path grid composed of a relatively thick metal layer with an underlying pn-junction, such as disclosed by G. C. Salter and R. E. Thomas in "Solid State Electronics" Vol. 20, 1977, pages 95-104, or a MIS Schottky contact such as disclosed by P. van Halen, R. Mertens, R. Van Overstraeten, R. E. Thomas, J. Van Meerbergen in "Proceedings of the European Photovoltaic Conf." 1977, pages 280-288, D. Reidel Publishing Co., Dordrecht, Holland/Boston, U.S.A. The area between the metal paths is coated with a transparent dielectric layer which can simultaneously function as an anti-reflection layer. Fixed insulator charges on the interface between the insulator and the semiconductor produce an inversion layer (composed of minority charge carriers) followed by a space charge zone in the semiconductor, directly beneath the dielectric layer. The inversion layer forms one side of an induced pn-junction in which a high electric field exists and which promotes the collection of the photo-charge carriers. The resistance of such inversion layer is comparatively low; in such thin surface inversion layers, the minority charge carriers produced by the light diffuse, as in a metal film, toward the contacts where they are discharged.
Similar to the above-discussed MIS cells, inversion layer solar cells must also exhibit a higher UV sensitivity than pn-cells because of the lower surface recombination velocity. In order for the conductivity of the inversion layer and thus for the photo-current to be as high as possible, the interface charge density (Q.sub.SS) must be as high as possible and at the same time the density of the fast surface states (N.sub.SS) must be low. The fast surface states reduce the conductivity due to the capture of minority charge carriers (recombination).
Accordingly, the main requirements for inversion layer solar cells are:
(1) a high density of fixed interface charges in order to achieve a highly conductive inversion layer;
(2) a low density of fast surface states in order to keep the loss (recombination) of charge carriers low.
When a thermally produced oxide is used as a dielectric on silicon, apart from the disadvantageous use of high temperatures of above 1000.degree. C. (power consumption, crystal defects, etc.) which are required to form such a layer, an increase in interface charge density, Q.sub.SS and thus a reduction in the layer resistance of the inversion boundary layers is always coupled with an increase in the density of the fast surface states, N.sub.SS. The increase in Q.sub.SS can be achieved by annealing in oxygen at relatively low temperatures and by selecting (111)-silicon in place of (100)-silicon as a substrate material. In extreme instances, Q.sub.SS /q values of approximately 1.times.10.sup.12 cm.sup.-2 are achieved together with very high N.sub.SS values of approximately 10.sup.12 cm.sup.-2 eV.sup.-1.

Solar cells composed of semiconductive materials


The present disclosure is related in general to content management and a method and system for generating a notification for an event. A notification generation system receives a recovery notification that indicates recovery from the event and contextual data associated with the event from a service provider. The event is a disruption caused in delivering multimedia content such as audio, video, text, images etc. to a user interested to access the multimedia content from the service provider. Further, the notification generation system generates the notification upon analysis of the recovery notification, the contextual data and predefined profile settings of the user. The notification is generated and provided to the user to indicate recovery of the multimedia content from transient disruption so that the user is well informed for better usage of services provided by the service provider. Further, the notification is provided on the preferred electronic devices of the user.

Generally, playback of content, live streaming of content etc. are performed through various devices and applications. For example, streaming of media assets from a server computer to one or more devices over a network. Occasionally content related errors may occur during the playback of the content or the live streaming of the content over managed or unmanaged networks. The error may occur due to network failure while delivering the content, server failures or server application failures that serve the content to be delivered etc. This may result in substantial loss for the content/service provider in terms of time and resources. Further, there is a risk of losing reliability factor if the errors occur persistently due to which users/subscribers may subscribe with other service providers for future ventures who may be more reliable.
Existing techniques have network monitoring or operations monitoring services that run-on servers which uses information from application services such as streaming servers, Content Delivery Network (CDN), Points of Presence (PoPs), rights services, listing services, subscriber services etc. and error handling infrastructures to understand faults that occur within the ecosystem. This can isolate problems that may occur at the backend and diagnose faults either immediately or over an extended period. However, in the existing techniques, user may not be aware that the content is available for consumption after a certain time period, upon resolving the faults, due to unavailability of a notification or an alert to the user. Due to the unavailability of the notification, the user may not be able to access the content at right time, hence, the user may try to access the same content in other devices before the error is diagnosed and encounter the same errors which may lead to unnecessary distress, bandwidth consumption, loss of valuable time of the user, the user may lose interest in accessing the content, the user may subscribe to another service provider for accessing the same content.

Method and a system for generating a notification for an event


A suspension control device includes an actuator configured to change an up/down stroke of a suspension, a front sensor, and a control device configured to estimate a displacement in a vertical direction of a road surface based on a detection result of the front sensor, thereby controlling the actuator. When the control device determines that a step portion in which a wheel comes into contact with two points of the road surface viewed in a direction along a rotational axis of the wheel exists ahead of a vehicle, the control device controls a force generated by the actuator so that, when the wheel comes into contact with the two points, the wheel rolls about the point without substantially pressing the point toward the travel direction of the vehicle.

1. Technical Field
The present disclosure relates to a suspension control device for a vehicle, e.g., a motor vehicle.
2. Description of the Related Art
As a suspension of a vehicle, there is known a suspension including an actuator for controlling an up/down stroke of the suspension or a force applied to the suspension. As a control device for this type of the suspension, there is known a control device for predicting an undulation of a road surface ahead of the vehicle, estimating a displacement in a vertical direction of the road surface based on a result of the prediction, and controlling the actuator so that the up/down stroke of the suspension changes depending on the displacement in the vertical direction of the road surface.
For example, in Japanese Patent Application Laid-open No. Hei 4-342612, there is described a control device configured to estimate a relative displacement between a vehicle body and a road surface and an up/down acceleration of the vehicle body at a prediction position ahead of a front wheel by a prediction distance, and to output to an actuator a command value for an optimal force or stroke when the front wheel reaches the prediction position based on the estimations. With this type of the control device, for example, when the relative displacement between the vehicle body and the road surface and the up/down acceleration of the vehicle body are detected, and the actuator is controlled based on a result of the detection thereof, a delay in control can be decreased, thereby decreasing a force applied from the road surface to the vehicle body via the front wheel.
With the control device disclosed in Japanese Patent Application Laid-open No. Hei 4-342612, when the change in the up/down displacement of the road surface is continuous, and a change rate of the up/down displacement is not high, a position of the wheel in the up/down direction can be changed depending on the up/down displacement of the road surface, thereby effectively decreasing the force applied from the road surface to the vehicle body via the front wheel.
However, on a portion where the change in the up/down displacement of the road surface is discontinuous or a portion where the change rate of the up/down displacement of the road surface is high, such as a step that the vehicle needs to move over and pass, a change amount of the relative displacement between the vehicle body and the road surface and a change amount of the up/down acceleration of the vehicle body are high at the prediction position. Therefore, with the control device described in Japanese Patent Application Laid-open No. Hei 4-342612, the command value for the force or the stroke output to the actuator rapidly fluctuates, and the force applied from the road surface to the vehicle body via the front wheel cannot effectively be decreased.
When there exists roughness on the road surface, such as a step whose change in the up/down displacement is discontinuous and large, a state occurs where the wheel comes into contact with two portions of the road surface viewed in a direction along a rotational axis of the wheel, and a portion on a leading side in a travel direction of the vehicle out of the two portions is higher than the other portion. When the vehicle passes over this roughness, the actuator is controlled so that the command value for the force or the stroke output to the actuator does not rapidly fluctuate. For example, as illustrated in FIG. 12, when a wheel 200 comes into contact with a road surface 202 at two portions P1 and P2, the actuator is controlled so that the lowest point P0 of the wheel 200 moves along a target trajectory 204 connecting the two portions P1 and P2 of the road surface 202 with each other.
However, as indicated by the broken line of FIG. 12, when the lowest point P0 of the wheel 200 is between the two portions P1 and P2, the wheel 200 moves toward the travel direction of the vehicle while pressing the portion P2. Thus, the wheel 200 receives a reaction force Fr of a pressing force Fp from the portion P2, the reaction force Fr acts on the wheel 200, and this force is transmitted from the wheel 200 to the vehicle body, which is not shown in FIG. 12. Thus, the force applied from the road surface to the vehicle body via the wheel and a vibration of the vehicle body caused by this force cannot effectively be decreased.


The present invention discloses a technique of effecting recording on a recording medium by a plurality of recording elements, wherein recording density by the plurality of recording elements is varied. Further, the recording density by the plurality of recording elements is varied in accordance with a time required for electrical transmission of informations to be recorded for definite numbers of scanning lines. For example, when the time required for such electrical transmission is short, the recording is effected by small numbers of the recording elements, while, when the time required for the electrical transmission is long, the recording operation is effected by large numbers of the recording elements, thereby preventing the image quality from lowering.

1. Field of the Invention
The present invention relates to a method and apparatus for recording of informations on a recording medium, in which a recording member consisting of a plurality of recording elements which perform recording of the informations is used to vary the recording density and reduce possible lowering of the image quality, thereby shortening the time required for the information recording.
2. Description of the Prior Arts
There have heretofore been contemplated various methods for recording image informations on recording paper. One example of such recording method is a so-called heat-sensitive recording method which is inexpensive in cost of the recording paper and easy for maintenance, on account of which the method has been widely used in various kinds of printers, medium and low speed facsimiles, and so forth. Since, however, the recording speed by this method is rather slow, it is not used at present for high speed facsimiles and printers.
When the image recording is to be made by the conventional thermal recording head, a time required for a period of from start of electric conduction accompanied by temperature increase in the head upto completion of the recording on the recording medium is usually from 0.5 ms to 1.0 ms, and a time required for cooling the head in preparation for the subsequent recording is approximately from 10 ms to 15 ms.
On the other hand, in the high speed facsimile which is generally called "one-minute facsimile", the shortest time T.sub.MIN for the electrical transmission of one line (a single scanning line in the image scanning operation) in case of transmitting a simple image information is usually 10 ms. Accordingly, considering from the above-mentioned recording characteristic, even when one line is simultaneously recorded using a thermal multihead for one line, the cooling time of the head becomes short, and deterioration in the recorded image such as ghost, etc. cannot be avoided.

Method and apparatus for facsimile recording


An individual selective call receiving device including a receiver unit has an intermittent receiving unit for intermittently operating the receiver unit in association with a group of a calling number assigned to the device. A collating unit sequentially collates a received synchronizing code sequence with a code sequence of a predetermined synchronizing code pattern, and sequentially collates a received selective calling code sequence with a code sequence of a predetermined selecting calling code pattern. A counter sequentially counts a number of error bits resultant from each of the collations. An intermittent operation control unit controls the intermittent receiving unit when a numeric value counted by the counter becomes equal to a preset threshold value, thereby turning the power of the receiver unit off.

The present invention relates to an individual selective call receiving apparatus achieving an intermittent receiving operation.
Conventionally, there have been utilized individual selective call receiving apparatuses handling various kinds of signal formats. FIG. 1 shows a representative signal format which is applied to the individual selective call receiving apparatuses in the conventional technology and which has been described in an article "The book of the CCIR Radiopaging Code No. 1" (Radiopaging Code Standards Group; 1986).
In FIG. 1, a transmission code is constituted with a preamble (repeatedly including "1" and "0") and a plurality of batches (first and second batches) following the preamble. The first batch includes a one-word (32 bits) synchronizing code word (SC) and an 8-frame (16 words) selective calling or call code. Accordingly, the respective selective call receiving apparatuses are classified into eight groups such that the receiving apparatuses of a group achieve a receiving operation only for a selective calling code of a frame beforehand assigned thereto.
In order to efficiently receive the code in the format above, the selective call receiving apparatus conducts an intermittent receiving operation.
FIG. 2 shows the configuration of a conventional intermittent receiving apparatus. FIG. 2 includes a bit synchronization unit 701 for detecting a change point of received data represented in the non-return-to-zero (NRZ) code system to generate a clock signal corresponding to the transmission speed, a frame synchronization unit 702 for detecting a synchronizing signal in the received NRZ data to produce a signal associated with an intermediate operation, and an intermediate operation unit 703. In operation, NRZ data is supplied to the bit synchronization unit 701 and the frame synchronization unit 702. The bit synchronization unit 701 then detects a change point of the received data to output the clock associated with the transmission speed to the frame synchronization unit 702.
As a result, the frame synchronization unit 702 detects a frame synchronizing signal in the received NRZ data to output an intermittent operation signal to the intermittent operation unit 703, thereby delivering the signal to the receiver unit through an intermittent operation of the intermittent operation unit 703. Namely, while establishing a synchronization with the transmission signal, the apparatus controls the receiver unit.
On the other hand, during a frame synchronization, each selective call receiving apparatus receives a calling code of a frame (own frame) beforehand assigned thereto and then achieves the collation of the individual calling number (identification or identifier collation).
Subsequently, the conventional method of identifier collation will be described. FIG. 3 is a diagram showing the selective calling code format. A selective calling code includes 32 bits as shown in FIG. 3, namely, bit 1 is an address/message flag, bits 2 to 19 denote a selective calling number, bits 20 and 21 are function bits (specifying a calling tone or sound pattern), bits 22 to 31 are Bose-Chaudhuri-Hocquenghem (31, 32) parity bits, and bit 32 is an even parity.
In the code system of this type, the distance d between codes is six (d=6) and hence a 3-bit error correction is theoretically possible in the collation of the fixed pattern, for example, in the identifier collation. However, ordinarily, a 1-bit or 2-bit error correction is adopted to avoid a risk of an erroneous collation between the identifiers.
Next, the identifier collation method will be specifically described. FIG. 4 shows an example of a conventional ID collating apparatus. In FIG. 4, the configuration includes a number ROM 901 loaded with a selective call number, an BCH generator unit 902 for generating a 32-bit BCH code for the selective call number written in the number ROM 901, a shift register 903 for storing therein the 32-bit code created by the BCH generator 902, a shift register 904 for storing therein received data, a shift register 905 disposed to conduct an identifier collation for the data loaded in the shift register 904, an exclusive OR gate 906 for achieving an exclusive OR between outputs from the shift registers 903 and 905, and a counter 907 for counting signals outputted from the exclusive OR gate 906.
A description will now be given of the operation of the identifier collating apparatus of the prior art. First, a reset signal RES is inputted to the counter 907 to reset the counter 907.
Next, received data (in the NRZ code system) is stored in the shift register 904 in response to a clock CLK1 supplied from the bit synchronization unit 701 shown in FIG. 2.
When the 32-bit data is completedly loaded in the shift register 904, a data transfer takes place to move the data from the shift register 904 to the shift register 905.
Moreover, a code series or sequence produced by the BCH generator 902 depending on the selective call signal loaded in the number ROM 901 is transferred to the shift register. In the situation where the shift registers 903 and 905 are thus loaded with the data, when a clock CLK2 having a higher speed than the clock CLK1 is inputted to the shift registers 903 and 905, the identifier collation is accomplished.
Namely, in response to the clock CLK2, data are respectively read from the shift registers 903 and 905 such that these output items are compared by the exclusive OR gate 906. Resultant signals of the comparison are counted by the counter 907.
In this case, when 32 clocks CLK2 are supplied to the counter 907, the value of the counter 907 is referenced. If a threshold value preset thereto is exceeded by the count value, an identifier collation mismatching is assumed; otherwise, an identifier collation matching results. The operation above is repeatedly carried out for four functions to thereby finish the identifier collation.

Individual selective call receiving apparatus

Matsushita Electric Industrial Co., Ltd.


An ultrasonic imaging apparatus for obtaining a two-dimensional distribution of a predetermined characteristic parameter of a medium of the ultrasound at various points in a plane. The apparatus contains a unit for designating a region of interest in said plane, and a unit for obtaining and indicating statistical information on a dispersing characteristic of said predetermined characteristic parameter of the medium at the various points in the region of interest of said plane. In addition, the apparatus contains a unit for obtaining and indicating a recent history of the dispersing characteristics during the operation of obtaining the two-dimensional distributions which are most recently carried out. Further, the apparatus contains a unit for obtaining and indicating the plane for which the minimum standard deviation is obtained, and a unit for indicating the two-dimensional distribution for the plane.

(1) Field of the Invention
The present invention relates to an ultrasonic imaging apparatus which functions to display an image of a two-dimensional distribution of a tissue characterization parameter of a tissue, for example, an ultrasonic attenuation coefficient, in a realtime mode.
In the field of the ultrasonic diagnosis, the two-dimensional distribution of the tissue characterization parameters, for example, an ultrasonic attenuation coefficient, an ultrasonic reflection coefficient, an elasticity parameter, are used to diagnose a condition of the tissue. For example, the value of the ultrasonic attenuation coefficient of tissue of a liver suffering from hepatitis is small compared with a normal tissue, and the value of the ultrasonic attenuation coefficient of a fatty liver is large compared with a normal tissue. Since high accuracy is required in ultrasonic diagnosis, the tissue characterization parameters must be determined precisely.
(2) Description of the Related Art
Conventionally, the ultrasonic imaging apparatus which functions to display an image of a two-dimensional distribution of a tissue characterization parameter of a tissue in a realtime mode is disclosed in the Japanese Unexamined Patent Publication No.62-109553, and the U.S. Pat. No.4,836,210 of Shiba et al, dated Jun. 6, 1989.
In ultrasonic imaging apparatuses, a pulsed beam of an ultrasound is generated to inject the beam into a tissue in a certain direction, and ultrasound which is reflected at various depths of the tissue in the same direction are detected. The direction of the pulsed ultrasound is scanned so that a plane is scanned by the pulsed ultrasound during one plane scan cycle. Thus, a two-dimensional distribution of the tissue characterization parameter on the plane (cross section of the tissue) is obtained. The above injection and detection of the ultrasound is carried out through an ultrasonic transducer array. The operator (doctor) applies a probe containing the transducer array on a skin of a human body to diagnose the condition of the tissue under the skin.
However, the obtained values of the above tissue characterization parameters fluctuate due to subtle movements of the probe or the tissue which is subject to the diagnosis. Further, for example, the values of the ultrasonic attenuation coefficient, which are obtained as above, greatly vary when a structure which is different from the tissue which is to be diagnosed, e.g., a vascular tract, exists in the scanned cross section. Generally, it is considered that the obtained values of the tissue characterization parameters are significant only when the obtained values are stable. Thus, generally, the values of the tissue characterization parameters must be obtained on a cross section of the tissue where the obtained values are stable. Nevertheless, conventionally, it is difficult for the operator to determine whether or not an obtained value of a tissue characterization parameter is stable. Therefore, in conventional ultrasonic imaging apparatuses, the credibility of the obtained values of the tissue characterization parameters is low.

Ultrasonic imaging apparatus indicating dispersion of characteristic parameter of medium


In various aspects, the invention provides for processing a hydrocarbon feed having hydrocarbon and emulsified aqueous components demulsifying into hydrocarbon and aqueous phases over an initial demulsification time, with an active agent to form a treated feed. The active agent has an active agent solubility in the hydrocarbon component and in the aqueous component, the aqueous component has an aqueous component solubility in the hydrocarbon component. The active agent solubility in the hydrocarbon component is greater than the aqueous component solubility in the hydrocarbon component. The active agent solubility in the aqueous component is greater than the active agent solubility in the hydrocarbon component. The active agent solubility in the aqueous component is greater than the active agent solubility in the hydrocarbon component. A treated demulsified hydrocarbon phase separates from the active agent and the aqueous component in a modified demulsification time that is shorter than the initial demulsification time.

In tar sands operations, bitumen is generally found in reservoirs comprising high concentrations of saline water. During various stages of processing the bitumen in situ and ex situ, the bitumen and water are prone to forming emulsions comprising water droplets finely dispersed throughout the bitumen matrix. Such emulsions are stabilized by the presence of various surfactant species and fine solids dispersed in the bitumen matrix, including in the aqueous phase, which prevent or interfere with coalescence of the water droplets during processing of bitumen feeds.
The concentration of water and various salt species in the bitumen matrix must be reduced to an acceptable level prior to downstream processing of the bitumen due to equipment operational requirements and the detrimental effects of the salts on the equipment such as corrosion, catalyst poisoning, negative impact on processing efficiencies and cost. Certain hydrocarbon feeds from heavy oil and offshore oil operations may also present similar emulsion and salt content challenges depending on the source of the hydrocarbon feed, and on added water in the hydrocarbon feed which must be subsequently removed for downstream operations.
Various methods have been used in the art to achieve a reduction in the water and salt contents in hydrocarbon feeds. A reduction in both water and salt content in bitumen, for example, may be achieved by removing the water comprising salts, which may include addition of fresh water to the hydrocarbon feed with mixing in order to promote coalescence of the fresh water droplets with saline water droplets, and thereby sediment and remove the saline water. However, in such processes, water-in-oil emulsions generally result from the mixing, and require further processing to promote separation of the hydrocarbon phase from residual water. Examples of conventional separation processes include gravity separation with and without the addition of demulsifiers to break water-in-oil emulsions, centrifugation, and electrostatic field treatment technologies. These processes are, however, often unsuccessful at effectively removing substantially all of the water and salts due to stable micro-emulsion formation.
Therefore, there is a need in the industry for processing hydrocarbon feeds to effect emulsion breaking, desalting, dewatering or a combination thereof to obtain feeds having water and salt contents reduced to levels suitable for downstream processing operations including upgrading.


A method of producing a Schottky junction including a semiconductor substrate and a metal film includes successively producing on a semiconductor substrate a first insulating film, a second film having a different etching speed from that of the first insulating film, and a third insulating film having a different etching speed from that of said second film, exposing a part of the second film by dry etching the third insulating film, etching the second film using the third insulating film as a mask to expose part of the first insulating film, dry etching the first insulating film to expose part of the substrate, and producing a metal film forming a Schottky junction with the substrate on the exposed part of the semiconductor substrate.

FIGS. 5(a)-5(d) are cross-sectional views showing a prior art production method of a Schottky barrier diode. In FIG. 5(a) reference numeral 1 designates a semiconductor substrate. An insulating film 2 is produced on the semiconductor substrate 1. A metal film 3 is provided on the semiconductor substrate 1 to produce one electrode of the Schottky barrier diode. Reference numeral 7 designates an aperture of the insulating film 2. The other electrode of the Schottky barrier diode is not shown here.
The production method of the Schottky diode is described with reference to FIGS. 5(a) to 5(d).
As shown in FIG. 5(a), a semiconductor substrate 1 is prepared. As this semiconductor substrate 1, for example silicon monocrystal is used.
Next, as shown in FIG. 5(b), an insulating film 2 is produced on the semiconductor substrate 1 by such as thermal oxidation or chemical vapor deposition. As this insulating film 2 silicon dioxide (SiO.sub.2) is used.
Next, as shown in FIG. 5(c), an aperture 7 is produced on the insulating film 2 at a portion on the semiconductor substrate 1 corresponding a portion where a Schottky barrier diode is to be produced. The production of this aperture can be easily performed by, for example when the insulating film is silicon dioxide film, producing a pattern of photoresist film on the silicon dioxide film by photolithography and etching the silicon dioxide film with a hydrofluoric acid solution using this photoresist film as a mask. By removing the photoresist film with sulfuric acid or an oxygen plasma after the etching, an aperture 7 is produced at the silicon dioxide film 2.
Then, as shown in FIG. 5(d), a metal thin film 3 is produced on the semiconductor substrate 1 in the aperture of the insulating film 2 and a Schottky barrier diode is thus produced. As a production method of this metal thin film 3, an electron beam deposition or sputtering is employed.
When platinum silicide is used for the metal film 3 and silicon is used for the semiconductor substrate 1, when annealing is performed after the platinum film is produced on the entire surface, the platinum in contact with silicon is silicided to produce platinum silicide, and when it is immersed in aqua regia after the annealing, platinum which is not silicided on the insulating film 2 is dissolved by the aqua regia and a metal side electrode of Schottky junction is selectively produced only at the aperture where the silicon substrate is exposed.
Because the Schottky diode is an element having a junction between the surface of a semiconductor substrate and a metal film in contact therewith, it is strongly influenced by the state of surface of the semiconductor and the crystallinity of semiconductor substrate in the vicinity of the surface. Accordingly, processes producing low contaimination and damage are required to be used for producing the insulating film 2 on the semiconductor substrate 1, for producing an aperture on the insulating film 2, and for producing metal electrode 3 of the Schottky diode.
Wet etching methods which have been utilized conventionally are those for removing material by using chemicals utilizing a chemical reaction at the liquid phase-solid phase interface. Those methods etch selectively between materials, have good processing ability, and do not damage the substrate. However, when this method is employed for producing a pattern, so-called transverse etching in which the etching advances with the solution circulating below the etching mask is likely to arise. Particularly when a photoresist which is inferior in adhesiveness to respective kinds of films constituting a semiconductor device is used, such transverse etching cannot be avoided.
When a Schottky barrier diode of FIG. 5(d) is integrated in integrated circuit, the film thickness of the insulating film 2 has to be approximately 1 micron in thickness in order to reduce the parasitic capacitance. When an aperture is to be produced on such a thick insulating film by utilizing a wet etching, etching in the transverse direction is large and a fine pattern is not obtained.
In recent fabrication process of semiconductor devices dry etching is used especially for monocrystalline silicon, polycrystalline silicon, silicon dioxide films, and aluminum films. Of dry etching processes, those utilizing reactive ion etching are advancingly developed.
These methods permit etching close to the dimension of a mask pattern because an etching reaction arises with reactive ions being accelerated in a direction perpendicular to the substrate surface and the etching amount in the transverse direction is small, so that a wide range of application is possible including to photoresist which has less adhesiveness to respective kinds of films constituting the semiconductor device, and to miniaturization of a pattern. As a result of that, it is possible to use a positive type photoresist and an apparatus of the step and repeat type can be used as an exposure apparatus in the photolithography, thereby enhancing the mask alignment precision where different kinds of films in the semiconductor device are successively processed using photoresist as mask material.
However, in RIE, etching is performed by reactive ions colliding with the film to be etched and damage accompanying the collision of ions and contaminations due to attachment of ions which do not participate in etching occurs.
Schottky barrier diodes are quite weak to the contamination of surfaces and defects in the vicinity of surface because they use a junction at an interface between the surface of semiconductor and the metal in contact therewith. Particularly in a device using a thin film of platinum silicide about 50 angstroms thick as in an infrared detecting element using a Schottky barrier diode of platinum silicide and silicon, the interface between the silicide and silicon is likely to be influenced by the silicon surface and it may become impossible to detect the infrared due to damage in silicon substrate. Thus, in the prior art device it was impossible to employ RIE for aperturing the insulating film 2 which is produced on the substrate 1.
Further, methods utilizing the above-described wet etching method and RIE in which a hole is dug through the insulating film 2 and thereafter an aperture is provided by wet etching is thought of. However, the etching speed by RIE easily varies dependent on the process conditions such as pressure and is difficult to control. Therefore, it is likely to cause variations in the depth of the apertures 7a to 7d of the insulating film 2 which is produced by RIE as shown in FIG. 6 caused by non-uniformity of etching speed in wafer surface over the entirety of the etched material, non-uniformity of the film thickness, variations in the film thickness of the etched material whereby the wet etching after the RIE cannot be performed uniformly.
As discussed above, in the prior art production process of a semiconductor device, there is a problem in that when a wet etching is used to produce an aperture in an insulating film on a substrate, a fine pattern is not obtained because of etching in the transverse direction and there is also a problem in that the RIE is inappropriate for production of a Schottky barrier diode because it damages the surface of substrate at the interface of Schottky junction and deteriorates the element characteristics. Further, in a method using RIE and wet etching for the production of an aperture of an insulating film, the etching by RIE cannot be performed uniformly in wafer, and the wet etching process thereafter cannot be performed with high controllability.

Method of producing a semiconductor structure including a Schottky junction


An oil cooler includes a plurality of tubes having both ends each fixed to a pair of header tanks in the length direction to form channels. The oil cooler further includes heat radiation fins, a first flange having an inlet pipe and an outlet pipe each coupled thereto in the length direction, a second flange coupled to any one of the header tanks in the length direction, and a bypass valve installed between the first flange and the second flange. The fixing bolts bolt the first flange, the bypass valve, and the second flange together while penetrating through the first flange, the bypass valve, and the second flange in the length direction.

A cooling module of an automobile is configured to include a radiator, a condenser, a fan shroud, an oil cooler, and the like.
The radiator is a device cooling an engine through heat exchange between a coolant and atmosphere.
The condenser is positioned at a front end of an engine room of the automobile and serves to cool a high temperature and high pressure gas refrigerant transferred from a compressor through heat exchange with air to convert the high temperature and high pressure gas refrigerant into a liquid-phase coolant.
The heat exchange of the condenser discharges heat obtained by the evaporator in a vehicle on an air conditioner system to the outside of the vehicle.
The fan shroud is positioned at the rear of the radiator and the condenser, and serves to operate a fan to forcibly pass wind therethrough, thereby maintaining cooling performance of the radiator and the condenser.
The fan shroud includes a fan having a pinwheel shape, a motor rotating the fan, and a shroud serving to support the motor and guide air, and is operated depending on a temperature of a coolant, an operation state of an air conditioner, a pressure of a refrigerant, and the like.
The oil cooler, which is a cooling device appropriately maintaining a temperature of oil including engine oil and mission oil, is divided into an embedded type water cooling oil cooler mounted in a radiator tank and an external type air cooling oil cooler mounted in a carrier, a cooling module, or the like.
The embedded type oil cooler serves to lower a temperature of the oil through heat exchange with a coolant, and the external type oil cooler serves to lower a temperature of the oil through heat exchange with atmosphere.
In addition, the oil cooler is installed with a bypass valve bypassing a low temperature oil so that the low temperature oil is not introduced into the oil cooler to thereby be cooled.
FIG. 1 is a schematic view of an oil cooler according to the related art.
As illustrated in FIG. 1, an oil cooler 1 according to the related art is configured to include a pair of header tanks 10 installed so as to be spaced apart from each other by a predetermined interval in a length direction; tubes 20 having both ends each fixed to the pair of header tanks in the length direction to form channels; heat radiation fins 30 interposed between the tubes; a bypass valve 50 connecting the header tank 10 to an inlet pipe 41 and an outlet pipe 42 in the length direction and bypassing oil transferred from the inlet pipe 41 to the header tank 10 to the outlet pipe 42 when a temperature of the oil is a predetermined temperature or less; and fixing bolts 60 bolting the bypass valve 50 while penetrating through the bypass valve 50 so as to be perpendicular to the length direction.
However, in the related art, a direction in which the fixing bolts are bolted and a direction in which the bypass valve is connected to the header tank are different from each other, such that bolting force of the fixing bolts is significantly decreased due to vibrations generated by oil moving in the bypass valve.
Particularly, in the related art, fatigue is easily accumulated in the fixing bolts to damage the fixing bolts, such that leakage is generated in the bypass valve.
Therefore, development of various oil coolers for solving the above-mentioned problems has been demanded.
As a technology associated with these oil coolers, a heat exchanger including a plug bypass valve has been suggested in U.S. Pat. Appl. Pub. No. 2003-0019620 A1.


The present invention relates to electrostatically actuated device components and methods of making the same. In an embodiment, the invention includes a method of making an electrostatically actuated device component including providing a multilayered structure comprising a first layer comprising a first polymer, a second layer comprising a conductive material, the second layer disposed over the first layer, a third layer comprising a dielectric material, the third layer disposed over the second layer, positioning the multilayered structure within an injection mold, and injecting a second polymer into the mold and bonding the first layer to the second polymer to produce an electrostatically actuated device component. In an embodiment, the invention includes a method of injection molding a stator component for an electrostatically actuated valve.

Many industrial, commercial, aerospace, military and other applications depend on reliable valves for fluid (including gas) handling. For example, in a chemical plant valves are often used to control the flow of fluid throughout the facility. Likewise, in an airplane, valves are often used to control air and fuel delivery, as well as some of the hydraulic systems that drive the control surfaces of the airplane. These are just a few examples of the many applications that depend on reliable valves for fluid handling.
It is often desirable to minimize the power and/or voltage required to operate valves, particularly in wireless applications but also in other applications. Some low voltage/power valves are known in the art. However, many low voltage/power valves and their components have a relatively high fabrication cost.


A fuel injector comprising a nozzle body provided with a first bore and defining a first seating, a valve member engageable with the first seating to control fuel flow from the first bore towards an outlet opening located downstream of the first seating, the valve member being provided with a second bore defining a second seating. A valve needle is slidable within the second bore and is engageable with the second seating to control fuel flow from the second bore towards a second outlet opening provided in the valve member. The fuel injector also includes a transmission arrangement whereby movement of the valve needle beyond a predetermined position is transmitted to the valve member.

It has been found that, with compression ignition internal combustion engines, the levels of noise and particulate emissions produced by the engine can be reduced by varying the rate at which fuel is supplied during each fuel injection cycle. For example, an injection cycle may include an initial phase during which fuel is supplied at a relatively low rate and a subsequent phase during which fuel is delivered at a higher rate. Alternatively, or additionally, other fuel injection characteristics may be varied. It is an object of the invention to provide a fuel injector meeting these requirements.
According to the present invention there is provided a fuel injector comprising a nozzle body provided with a first bore and defining a first seating, a valve member engageable with the first seating to control fuel flow from the first bore towards a first outlet opening located downstream of the first seating, the valve member being provided with a second bore defining a second seating, a valve needle being slidable within the second bore and being engageable with the second seating to control fuel flow from the second bore towards a second outlet opening provided in the valve member, and a transmission arrangement whereby movement of the valve needle beyond a predetermined position is transmitted to the valve member.
The nozzle body may be provided with a plurality of first outlet openings and the valve member may be provided with a plurality of second outlet openings.
The first and second outlet openings may be located such that, when the valve member engages the first seating and the valve needle is lifted from the second seating, the first and second outlet openings are arranged in series with one another, movement of the valve member away from the first seating permitting fuel delivery through the first outlet opening, by-passing the second outlet opening. It will be appreciated, that depending upon the shape and size of the first and second outlet openings, the fuel delivery rate or other fuel injection characteristics may be varied by varying the distance by which the valve needle is moved.
The number of first outlet openings may be equal to the number of second outlet openings. Alternatively, fewer second outlet openings may be provided, in which case only some of the first outlet openings are used to deliver fuel whilst the valve member engages the first seating and the valve needle is lifted away from the second seating.
Alternatively the valve member may include a tip portion provided with an opening to allow passage of fuel from the second bore to the first outlet opening, the tip portion being arranged to partially cover the first outlet opening when the valve member engages the first seating and being moveable to a position in which the first outlet opening is not covered by the tip portion.
The second outlet opening in the valve member may be an axially extending opening. Movement of the valve needle away from the second seating by an amount which does not exceed a predetermined amount permits fuel to flow from the second bore in the valve member through an axially extending opening into the first outlet opening. As the first outlet opening is partially obscured by the tip portion, the rate at which fuel is delivered is limited. As movement of the valve needle is not transmitted to the valve member, fuel does not flow past the first seating directly to the first outlet opening. Thus, fuel delivery occurs at a relatively low fuel delivery rate. Further movement of the valve needle away from the second seating beyond the predetermined amount results in movement of the valve member away from the first seating and thus permits fuel to flow from the first bore, past the first seating, directly to the first outlet opening, therefore by-passing the axially extending opening in the valve member. The movement of the valve member results in the tip portion moving to a position in which it does not throttle fuel delivery, thereby permitting a higher fuel delivery rate.
The tip portion may be of truncated, conical form, the tip portion partially covering the first outlet opening in the nozzle body when the valve member engages the first seating such that fuel flow through the opening is throttled, thereby permitting a low fuel delivery rate.
This embodiment of the invention provides the advantage that accurate radial guidance of the valve needle is not essential. The construction of the fuel injector is therefore less complex and manufacture is simplified. Additionally, the first outlet opening can be located at a lower axial position in the nozzle body, as there are no openings in the valve needle with which the first outlet opening must align. Thus, the allowable pressure limit for the injector can be increased.
The fuel injector conveniently includes a sac formed downstream of the first seating and communicating with the first outlet opening formed in the nozzle body, the axially extending opening in the valve member communicating with the sac to enable fuel to flow through the axially extending opening into the sac and out through the first outlet opening in the nozzle body. Preferably, the sac is of truncated conical form so as to minimise the dead volume.


A nuclear fuel assembly includes guide tubes having integral ridges oriented and spaced to increase coolant flow in the gap between the guide tubes and adjacent fuel elements.

In water-cooled nuclear reactors, the reactor core in which the fission chain is sustained generally contains a multiplicity of fuel element assemblies, also known as fuel assemblies, that are identical in mechanical construction and mechanically interchangeable in any core fuel assembly location. Each fuel assembly is designed to maintain its structural integrity during reactor heatup, cool-down, shut-down and power operations including the most adverse set of operating conditions expected throughout its lifetime. Design considerations for reactor operation include the combined effects of flow induced vibration, temperature gradients, and seismic disturbances under both steady state and transient conditions.
Each fuel assembly typically contains a plurality of thin elongated fuel elements, a number of spacer grid assemblies, guide tubes, an instrumentation tube, and end fittings.
The fuel elements used in current applications are known as fuel rods and comprise cylindrical UO.sub.2 fuel pellets stacked end to end within a thin walled tube (cladding), often having spring loaded plenums at each end of the tube, that is hermetically sealed with end caps or plugs. The fuel rod cladding is made from a material, such as a zirconium alloy, which has good neutron economy, i.e. a low capture cross section. Depending upon the position of a fuel assembly within the core, a number of elongated cylindrical guide tubes, arranged in parallel with fuel rods, are used variously to provide continuous sheath guidance for axially translatable control rods, axial power shaping rods, burnable poison rods, or orifice rods. Sufficient internal clearance is provided to permit coolant flow through the guide tubes to limit the operating temperatures of the absorber materials which may be inserted therein, and to permit rod insertion and withdrawal motions therewithin during all phases of reactor operation. The guide tubes have a larger cross-section or diameter than the fuel rods.
Each fuel rod transfers nuclear fission generated heat to circulating coolant water, circulating through parallel flow passages or coolant channels between the adjacent parallelpiped fuel rods, guide tubes and the instrumentation tube. The coolant channels are associated with an effective flow area transverse to the channel length. The various types of coolant channels are alternatively defined by the flow area between adjacent fuel rods (known as unit channels), by the flow area between a guide tube or instrument tube and adjacent fuel rods (known as guide tube channels), or by the flow area between fuel rods and an adjacent flow barrier such as the thermal shield of the reactor. The flow area of a guide tube channel is smaller than the flow area of a unit channel due to the larger cross-section of the guide tubes.
In each fuel assembly, fuel rods, guide tubes and instrumentation tube are typically supported in a square array at intervals along their lengths by spacer assemblies that maintain the lateral spacing between these components in an open-lattice arrangement. Each spacer assembly is generally composed of a multiplicity of slotted rectangular grid plates arranged to intersect and interlock in an egg-crate fashion to form cells through which the fuel rods and guide tubes extend in a parallel array. Illustratively, the grid plates may be of the type, such as described in U.S. Pat. No. 3,665,586 by F. S. Jabsen and assigned to The Babcock & Wilcox Company, which have indentations that laterally extend essentially perpendicular to the longitudinal axes of the fuel rods into those cells which have fuel rods for engagement and support of the fuel rods. These spacer grids typically accommodate and support the larger control rod guide tubes and the instrument tube in cells not having such indentations. Despite the difference in the diameter of the fuel rods relative to that of the guide tubes or instrumentation tube, all of these parallelpiped components are arrayed in a uniform square pitch, that is have equal center to center distance, within the fuel assembly.
The spacer assemblies maintain a necessarily precise spacing between fuel rods in order to avoid neutron flux peaks and regions of abnormally high temperature (hot spots) where burnout, i.e. severe local damage to the fuel rods, could occur. The spacer assemblies assure the mechanical stability that is essential to preclude the distortions which may be otherwise caused by flow induced vibrations, pressure differences, and thermal stress.
Coolant typically flows upwardly through the flow channels parallel to the surrounding members. Since the flow areas of the channels differ, the flow rate is not the same in each type of flow channel.
The design of the reactor core is limited by the heat transfer rate from the fuel to the coolant. The limiting or "critical" heat flux is defined by the onset of the departure from nucleate boiling (DNB). This condition marks the transition into an area of low heat transfer coefficient and a very high fuel element surface temperature which can eventually lead to burnout. DNB can occur if the fuel element heat flux is too great for a given coolant flow. Reactor core design criteria, therefore, are partly based on the establishment of a maximum permissible heat flux in the so-called "hot channel" which is a fraction of the calculated burnout flux. Safety margins between the maximum permissible heat flux and the critical heat flux, characterized as "minimum DNB ratios," are set for the various flow channel types in order to provide an adequate margin of safety under all conditions.
Experimental studies indicate that critical heat flux values in fuel element assemblies are generally lower in the smaller guide tube channels than in unit channels. Thus, the guide tube channels are, in the sense, a limiting factor in reactor operation, particularly within the "gap" defining the closest spacing between a guide tube and adjacent fuel rod.

Nuclear fuel assembly guide tube with integral intermittent projections


Near-duplicate documents may be identified by processing an accepted set of documents to determine a first set of near-duplicate documents using a first technique, and processing the first set to determine a second set of near-duplicate documents using a second technique. The first technique might be token order dependent, and the second technique might be order independent. The first technique might be token frequency independent, and the second technique might be frequency dependent. The first technique might determine whether two documents are near-duplicates using representations based on a subset of the words or tokens of the documents, and the second technique might determine whether two documents are near-duplicates using representations based on all of the words or tokens of the documents. The first technique might use set intersection to determine whether or not documents are near-duplicates, and the second technique might use random projections to determine whether or not documents are near-duplicates.

§1.1 Field of the Invention
The present invention concerns information management and retrieval in general. More specifically, the present invention concerns detecting, and optionally removing, duplicate and near-duplicate information or content, such as in a repository of documents to be searched for example.
§1.2 Background Information
In the following, the term "document(s)" should be broadly interpreted and may include content such as Web pages, text files, multimedia files, object features, link structure, etc. Also, it should be noted that when near-duplicate documents are detected, exact duplicate documents will also be detected as a consequence (though such exact duplicates might not necessarily be distinguished from near-duplicates).
Detecting near-duplicate documents has many potential applications. For example, duplicate or near-duplicate documents may indicate plagiarism or copyright infringement. One important application of near-duplicate document detection is in the context of information storage and retrieval.
Efficient techniques to detect documents that are exact duplicates exist. Detecting whether or not documents are near-duplicates is more difficult, particularly in large collections of documents. For example, the Internet, collectively, includes literally billions of "Web site" documents.
Sources of duplicate and near-duplicate documents on the Internet are introduced in §1.2.1 below. Then, problems that these duplicate and near-duplicate documents raise, both for end-users and for entities assisting end-users, are introduced in §1.2.2 below. Finally, previous techniques for detecting duplicate and near-duplicate documents in the context of large document collections, as well as perceived shortcomings of such techniques, are introduced in §1.2.3 below.
§1.2.1 Sources of Duplicate and Near-Duplicate Documents on the Internet
On the Internet, the World Wide Web (referred to as "the Web") may include the same document duplicated in different forms or at different places. (Naturally, other networks, or even stand alone systems, may have duplicate documents.) Sources of such duplication are introduced here.
First, some documents are "mirrored" at different sites on the Web. Such mirroring is used to alleviate potential delays when many users attempt to request the same document at the same time, and/or to minimize network latency (e.g., by caching Web pages locally).
Second, some documents will have different versions with different formatting. For example, a given document may have plain text and HTML (hyper-text markup language) versions so that users can render or download the content in a form that they prefer. As more and more different devices (e.g., computers, mobile phones, personal digital assistants, etc.) are used to access the Internet, a given document may have more and more different versions with different formatting (text only, text plus other media, etc.).
Third, documents are often prepended or appended with information related to its location on the Web, the date, the date it was last modified, a version, a title, a hierarchical classification path (e.g., a Web page may be classified under more than one class within the hierarchy of a Web site), etc.
Fourth, in some instances a new document is generated from an existing document using a consistent word replacement. For example, a Web site may be "re-branded" for different audiences by using word replacement.
Finally, some Web pages aggregate or incorporate content available from another source on the Web.
§1.2.2 Problems Raised by Duplicate and Near-Duplicate Documents
Duplicate and near-duplicate documents raise potential problems for both people accessing information (e.g., from the Web) and entities helping people to access desired information (e.g., search engine companies). These potential problems are introduced below.
Although people continue to use computers to enter, manipulate and store information, in view of developments in data storage, internetworking (e.g., the Internet), and interlinking and cross referencing of information (e.g., using hyper-text links), people are using computers (or more generally, information access machines) to access information to an ever increasing extent.
Search engines have been employed to help users find desired information. Search engines typically search databased content or "Websites" or "Web pages" pursuant to a user query. In response to a user's query, a rank-ordered list, which typically includes brief descriptions of the uncovered content, as well as hyper-texts links (i.e., text, having associated URLs) to the uncovered content, is returned. The rank-ordering of the list is typically based on a match between words appearing in the query and words appearing in the content.
From the perspective of users, duplicate and near-duplicate documents raise problems. More specifically, when users submit a query to a search engine, most do not want links to (and descriptions of) Web pages which have largely redundant information. For example, search engines typically respond to search queries by providing groups of ten results. If pages with duplicate content were returned, many of the results in one group may include the same content. Thus, there is a need for techniques to avoid providing search results associated with (e.g., having links to) Web pages having duplicate content.
From the perspective of entities hosting search engines, duplicate and near-duplicate documents also raise problems—giving end-users what they want, being one of them. To appreciate some of the other potential problems raised by duplicate and near-duplicate documents, some search engine technology is introduced first.
Most search engines perform three main functions: (i) crawling the Web; (ii) indexing the content of the Web; and (iii) responding to a search query using the index to generate search results. Given the large amount of information available, these three main functions are automated to a large extent. While the crawl operation will associate words or phrases with a document (e.g., a Web page), the indexing operation will associate document(s) (e.g., Web page(s)) with words or phrases. The search operation then (i) uses that index to find documents (e.g., Web pages) containing various words of a search query, and (ii) ranks or orders the documents found in accordance with some heuristic(s).
Recall that the Web may include the same documents duplicated in different forms or at different places on the Web. For example, as introduced in §1.2.1 above, documents may be "mirrored" at different sites on the Web, documents may have a number of different formats so that users can render or download the content in a form that they prefer, documents may have a different versions with different information prepended or appended, some documents may have been generated from others using consistent word replacement, and some documents may aggregate or incorporate documents available from another source on the Web. It would be desirable to eliminate such duplicates or near-duplicates. Besides eliminating duplicate or near-duplicate documents to meet user expectations and wishes, eliminating duplicate or near-duplicate documents is desirable to search engine hosting entities to (i) reduce storage requirements (e.g., for the index and data structures derived from the index), and (ii) reduce the time and/or computational resources needed to process indexes, queries, etc.
In view of the foregoing, techniques to detect (and eliminate) near-duplicate documents are needed.
§1.2.3 Known Techniques for Detecting Duplicate and Near-Duplicate Documents and their Perceived Limitations
A naive solution would be to compare all pairs to documents. Since this is prohibitively expensive on large datasets, Manber (U. Manber, "Finding similar files in a large file system," Proc. of the USENIX Winter 1994 Technical Conference (January 1994)) and Heintze (N. Heintze, "Scalable Document Fingerprinting," Proc. of the 2nd USENIX Workshop on Electronic Commerce (November 1996)) proposed algorithms for detecting near-duplicate documents that reduced the number of comparisons. Both algorithms work on sequences of adjacent characters. Brin et al. (S. Brin, J. Davis, and H. Garcia-Molina, "Copy Detection Mechanisms for Digital Documents," 1995 ACM SIGMOD International Conference on Management of Data, pp. 398-409 (May 1995)) started to use word sequences to detect copyright violations. Broder et al. (A. Broder, S. Glassman, M. Manasse, and G. Zweig, "Syntactic Clustering of the Web," 6th International World Wide Web Conference, pp. 93-404 (April 1997), incorporated herein by reference) also used word sequences to efficiently find near-duplicate Web pages. Later, Charikar (M. S. Charikar, "Similarity Estimation Techniques from Rounding Algorithms," 34th Annual ACM Symposium on Theory of Computing (May 2002), incorporated herein by reference. See also U.S. Patent Application Publication 2006/0101060, also incorporated herein by reference.) developed an approach based on random projections of the words in a document. Recently Hoad and Zobel (T. C. Hoad and J. Zobel, "Methods for identifying versioned and plagiarised documents," Journal of the American Society for Information Science and Technology, 54(3), pp. 203-215 (2003)) developed and compared methods for identifying versioned and plagiarized documents. Unfortunately, however, the technique recommended by Hoad and Zobel is inefficient, having O(N2) computational complexity, where N is the number of documents to be compared with a document of interest.
§184.108.40.206 Introduction of the Broder and Charikar Algorithms for Document Similarity
In both the Broder and Charikar algorithms, each HTML page is converted into a token sequence. The two algorithms differ only in how they convert the token sequence into a bit string representing the page.
To convert an HTML page into a token sequence, all HTML markup in the page is replaced by white space or, in case of formatting instructions, ignored. Then every maximal alphanumeric sequence is considered a term and is hashed using Rabin's fingerprinting scheme (M. Rabin, "Fingerprinting by random polynomials," Report TR-15-81, Center for Research in Computing Technology, Harvard University (1981), incorporated herein by reference) to generate tokens, with two exceptions.
Both algorithms generate a bit string from the token sequence of a page and use it to determine the near-duplicates for the page.
Let n be the length of the token sequence of a page. Using the Broder algorithm every sub-sequence of k tokens (where the sub-sequences overlap) is fingerprinted using 64-bit Rabin fingerprints, which results in a sequence of (n−k+1) fingerprints, called "shingles". Let S (d) be the set of shingles of the page "d". The Broder algorithm makes the assumption that the percentage of unique shingles on which the two pages d and d′ agree. That is, the Broder algorithm assumes that
                        S                          (          d          )                    ⋂              S                          (                      d            ′                    )                                                S                          (          d          )                    ⋃              S                          (                      d            ′                    )                        is a good measure for the similarity of d and d′.
The foregoing may be approximated by fingerprinting every shingle with m different fingerprinting functions fi for 1≦i≦m. This leads to (n−k+1) values for each fi. For each i, the smallest of these values is called "the i-th minvalue" and is stored at the page. As a result, the Broder algorithm creates an m-dimensional vector of minvalues. Broder et al. showed that the expected percentage of entries in the minvalues vector that two pages d and d′ agree on is equal to the percentage of unique shingles on which d and d′ agree. Thus, to estimate the similarity of two pages, it suffices to determine the percentage of agreeing entries in the minvalues vectors. To save space and speed up the similarity computation, the m-dimensional vector of minvalues might be reduced to an m′-dimensional vector of supershingles by fingerprinting non-overlapping sequences of minvalues. Let m be divisible by m′ and let =m/m′. The concatenation of minvalue j * . . . , (j+1)*−1 might be fingerprinted for 0≦•j<m′ with yet another fingerprinting function. (Note that the notion of "megashingles" was also introduced in the Broder et al. paper in order to further speed up the algorithm. Megashingles are generated by fingerprinting every pair of supershingles, such that each megashingle is a fingerprinted pair of supershingles. Since, however, using megashingles does not improve precision or recall, they need not be used.) Two pages are near-duplicates under the Broder algorithm (referred to here as "B-similar") if and only if their supershingle vectors agree in at least two supershingles. The number of identical entries in the supershingle vectors of two pages is their "B-similarity". The parameters for the Broder algorithm are m, m′, and k.
As can be appreciated from the foregoing, the Broder algorithm is order dependent (e.g., since the shingles are fingerprints of overlapping sub-sequences), but is independent of the frequency of the shingles.
The Charikar algorithm is now described. Let b be a constant. Each token is projected into b-dimensional space by randomly choosing b entries from {−1, 1 }. The resulting b-dimensional vector may be referred to as a "token vector". The same tokens, whether occurring on the same page or on different pages, will have the same b-dimensional representation (i.e., the same "token vector"). For each page, a representative b-dimensional vector (which may be referred to as an "initial page vector") is created by adding the projections of all the tokens in the page's token sequence (i.e., adding all of the page's "token vectors"). The final vector for the page (which may be referred to as a "final page vector") is created by setting every positive entry in the vector to 1 and every non-positive entry to 0. The generates a random b-dimensional projection (i.e., a final page vector) for each page. The final page vectors have the property that the cosine similarity of two pages is proportional to the number of bits in which the two corresponding projections agree. That is, similarity in the Charikar algorithm (referred to as "C-similarity") of two Web pages is the number of bits their projections agree on. Two pages are near-duplicates in the Charikar algorithm (or are C-similar) if the number of agreeing bits in their projections is above a fixed threshold t.
As can be appreciated from the foregoing, given the definition of minvalues (from which supershingles, and perhaps even megashingles, are generated), Broder's technique uses representations based on a subset of the words (or tokens) of the original document being analyzed. On the other hand, Charikar's technique uses representations based on all words (not removed by preprocessing) (or tokens) of the original document being analyzed. That is, Charikar's technique might consider all words (or tokens) of documents accepted as inputs. Further, Broder's technique uses set intersection to determine whether or not documents are near-duplicates. On the other had, Charikar's technique uses random projections to determine whether or not documents are near-duplicates.
As can be appreciated from the foregoing, in both algorithms pages with the same token sequence are assigned the same bit string. The Charikar algorithm ignores the order of the tokens (given the additive aspect of generating a page vector from token vectors). The shingles of the Broder algorithm are based on the order of the tokens. However, the Broder algorithm ignores the frequency of shingles. On the other hand, the Charikar algorithm accounts for the frequency of terms (again, given the additive aspect of generating a page vector from token vectors). For both algorithms there can be false positives (non near-duplicate pairs returned as near-duplicates) as well as false negatives (near-duplicate pairs not returned as near-duplicates.)
Let T be the sum of the number of tokens in all documents and let D be the number of documents. The Broder algorithm takes time O(Tm+Dm′)=O(Tm). The Broder algorithm takes time O(Tb) to determine the vector for each page. As described below, the C-similar pairs might be computed using a trick similar to supershingles. It takes time O(D) so that the total time for the Charikar algorithm is O(Tb).
Some embodiments consistent with the present invention might further (d) process the set of documents to determine a third set of near-duplicate documents using the second document similarity technique, (e) determine a fourth set of near duplicate documents by determining the union of the second set of near duplicate document and the third set of near-duplicate documents.
§184.108.40.206 Evaluation of the Broder and Charikar Algorithms
The present inventor evaluated the Broder and Charikar algorithms on 1.6 B distinct Web pages, according to three criteria—(1) precision on a random subset, (2) the distribution of the number of term differences per near-duplicate pair, and (3) the distribution of the number of near-duplicates per page. All parameters in the Broder algorithm were set as suggested in the literature. The parameters in the Charikar algorithm were chosen so that it used the same amount of space per document and returned about the same number of correct near-duplicate pairs (i.e., had about the same recall).
The present inventor found that the Charikar algorithm achieved a precision of 0.50, while the Broder algorithm achieved a precision of 0.38. Both algorithms were found to perform about the same for near-duplicate pairs on the same site (low precision) and for near-duplicate pairs on different sites (high precision). However, over 90% of the near-duplicate pairs found by the Broder algorithm belonged to the same site, but only 74% of the near-duplicate pairs found by the Charikar algorithm belonged to the same site.
Thus, the Charikar algorithm found more of the near-duplicate pairs for which precision is high. The number of term differences per near-duplicate pair was found to be very similar for the two algorithms, but the Broder algorithm returned fewer pairs with extremely large term differences. The distribution of the number of near-duplicates per page was found to follow a power-law for both algorithms. However, the Broder algorithm was found to have a higher "spread" around the power-law curve. The present inventor believes that a possible reason for that "noise" is that the bit string representing a page in the Broder algorithm is based on a randomly selected subset of terms in the page. Thus, there might be "lucky" and "unlucky" choices, leading to false near-duplicate pairs or missing actual near-duplicate pairs. The Charikar algorithm does not select a subset of terms but is based on all terms in the page.
The present inventor found that neither of the algorithms worked well for finding near-duplicate pairs on the same Website, though both achieved high precision for near-duplicate pairs on different Websites.
In view of the foregoing, it would be useful to provide improved techniques for finding near-duplicate documents. It would be useful if such techniques improved the precision of the Broder and Charikar algorithms. Finally, it would be useful if such techniques worked well for finding near-duplicate pairs on the same Website, as well as on different Websites.

Detecting duplicate and near-duplicate files


A retrievable dental prothesis fabricated by using a special plastic cylinder using low-wax casting procedures for the purpose of eliminating the need for a visible titanium abutment cylinder typically used for conventional prostheses. This improves the appearance and functional features of the prosthesis. The prosthesis is connected by a titanium alloy screw directly to an implant embedded in a patient's underlying dental bone structure. Internal hexagonal surfaces formed at the base of the prosthesis which mate with hexagonal surfaces of an upward extension of the implant prevent loosening or rotation of the prosthesis due to rotational forces and vibrations and enable fabrication of single implant-supported restoration. However, the prosthesis may be used without such internal hexagonal surfaces if desired. Because an abutment cylinder is not used, the prosthesis provides increased working space between the implant and corresponding opposite upper or lower existing teeth. An access aperture may be provided at the back of the prosthesis for allowing access by an installation tool to the titanium alloy screw. The prosthesis is formed by shaping a wax pattern around the plastic cylinder to represent a patient's tooth to be replaced by the prosthesis. The prosthesis is then cast out of gold-palladium alloy. A bottom surface at the base of the prosthesis is polished using a lapping tool and guide pin. Cutting edges may be used on the lapping tool to facilitate deburring of the bottom surface.

The present invention relates generally to dental prosthesis and, more particularly, to a retrievable dental prosthesis fabricated by using a special plastic cylinder during lost-wax casting procedures for the purpose of eliminating the need for a visible titanium abutment cylinder typically used for a conventional prosthesis in order to improve the appearance and functional features of the prosthesis.
In the past, the development of osseointegrated implants has allowed dental restorations or prostheses to be used with conventional titanium implants placed in a patient's bone structure underlying missing teeth for the purpose of replacing the lost teeth. Osseointegration (or bonding between the bone and implant) occurs so that the implant functions as a secure base on which to support a prosthesis. A conventional titanium (transmucosal) abutment cylinder is connected to the implant. The abutment is typically cemented to the implant or attached to it by a screw. As such, the abutment cylinder emerges from a patient's soft tissue (gum) and provides a structure upon which to mount the prosthesis. A prosthesis shaped like a tooth usually having a conventional cylinder incorporated into it is typically connected to the abutment cylinder by a screw.
Some problems have resulted in the past when a conventional titanium abutment cylinder has been used. For example, the titanium abutment cylinder extends from a patient's gum tissue (from the gingival crest) presenting an undesirable appearance due to the visible metallic cylinder. Also, inadequate interocclusal space between the abutment cylinder and opposing dentition may result in insufficient space for a conventionally designed prosthesis. Even when the shortest titanium abutment cylinder (3 mm) is used, the conventional cylinder incorporated within the prosthesis may be too large for the available working space. The heights of the conventional cylinder and the head of the cylinder screw may be decreased to accommodate the reduced working space, but this may compromise the integrity of the prothesis.
A conventional prosthesis typically uses a titanium abutment cylinder that is either cemented to an implant or secured to it by a screw. Rotation of the abutment cylinder with respect to the implant is prevented by cementing the two parts together or using male and female mating surfaces (e.g., hexagonal extension from implant mating with internal hexagonal surfaces in abutment cylinder). However, the conventional cylinder is not cemented to the abutment cylinder, nor do these two parts have mating male and female surfaces that prevent rotation of the parts. A screw holds the conventional cylinder to the titanium abutment cylinder.
Loosening and rotation of the conventional and titanium abutment cylinders with respect to each other will take place when the cylinders experience sufficient rotational forces and vibration. Rotation and loosening would be less likely if the prosthesis is anchored to another prosthesis, or a natural tooth (or adjacent teeth). However, prostheses using such anchoring means to prevent loosening and rotation thereof are more expensive and less attractive in appearance than a prosthesis not using such anchoring means.
Another disadvantage of some conventional prostheses relates to the difficulty in treating infections or other dental problems that may develop in those dental cases where the titanium abutment cylinder is cemented to the implant. In such cases, surgery may be required to remove the cemented parts in order to treat the problem areas.
Many of these problems would be eliminated or improved by providing a prosthesis directly connected at its base to an implant that may be easily removed from the implant and that uses mating male and female surfaces to prevent rotation. The prior art does not disclose or suggest such a prosthesis, which would eliminate the need for an unsightly titanium abutment cylinder, provide increased working space between the implant and a corresponding upper or lower tooth due to elimination of the abutment cylinder, prevent rotation of the prosthesis with respect to the implant, and allow removal of the prosthesis for maintenance, oral hygiene, or when infections occur.
In addition, proper dental hygiene may be difficult when a titanium abutment cylinder is used because the titanium abutment cylinder may not provide appropriate hygiene access or desirable contours near soft tissue areas adjacent the cylinder required for oral hygiene and a healthy gingival response. Also, plaque tends to accumulate more readily on a machined metal surface, such as a titanium abutment cylinder, than on, for example, a polished porcelain surface.

Retrievable dental prothesis apparatus and method of fabrication


A method and device for avoiding manipulation of a data transmission. A message containing a message authentication code is received at a processing unit, the message from the processing unit is transferred to a hardware module, a check value as a function of the received message is computed in the hardware module, the received message authentication code and the check value are compared in the hardware module, a result of the comparison is transferred from the hardware module to the processing unit as an output variable, the message authentication code received in the message from the processing unit is checked in the processing unit based on the output variable.

German Patent Application No. DE 10 2009 002 396 A1 describes a method for protecting data transmissions in a vehicle from manipulation with the aid of message authentication code.
Messages which are transmitted in vehicles, for example, via a controller area network or FlexRay databus, are provided with a checksum, for example, for a cyclic redundancy check. Safety-critical messages are checked on the receiver side using this checksum.
The checksum may also be supplemented or replaced by the message authentication code.
The check is carried out with the aid of software and/or hardware specifically adapted for this purpose.
To prevent manipulations, the software and/or hardware may be developed according to the so-called principle of least privilege. Accordingly, each module, i.e., each processor or each program within the overall system only has access to the information or resource which is necessary for fulfilling the particular purpose.
If a special hardware module is used for checking the message authentication code, the principle of least privilege may be violated in that the special hardware module may also be used for generating a message authentication code. This makes it possible for a compromised recipient of a message to also send a falsified message having a valid message authentication code in the name of the original sender.

Method and device for avoiding manipulation of a data transmission


A plasma generator system for reducing the effects of impedance mismatch. The system has a variable frequency source having an output for emitting an RF signal. A plasma chamber has an input for receiving the RF signal. The variable frequency source modulates at least one of the frequency and phase of the RF signal to improve the system tolerance of impedance mismatches between the output of the variable frequency source and the input of the plasma chamber.

Radio frequency (RF) generators are used to drive plasma chambers for various applications such as etching, semiconductor fabrication, and flat panel displays. Industry specified frequencies for operating RF power generators include 2 MHz, 4 MHz, 8 MHz, 3.2 MHz, 13.56 MHz, 60 MHz, and 100 MHz.
Known RF generators use continuous wave (CW) single-tone narrow-band signals which fix an RF carrier frequency at a desired operating frequency. However, an input impedance of the plasma chamber as seen by the RF generator may change drastically during operation due to perturbations of the plasma. When the input impedance changes, a possibility exists for a mismatch between the input impedance of the plasma chamber and an output impedance of the RF generator. The mismatch may be so significant that reflected waves from the plasma chamber severely impact operation of the RF generator. Alternatively, the RF generator may be self-protected and designed to turn off or reduce its output power upon detecting the significant mismatch. Either of these responses by a self-protected RF generator may cause the plasma to extinguish, which is also undesirable.

Broadband techniques to reduce the effects of impedance mismatch in plasma chambers