Example scheduling assignment information transmission methods, systems, and devices are described. One example method includes obtaining, by a user equipment (UE), a multiplexing manner used to indicate a relationship between a time-frequency resource for transmitting scheduling assignment information and a time-frequency resource for transmitting data information. The UE receives downlink control information comprising scheduling assignment resource indication information sent by a network device, and obtains, based on the scheduling assignment resource indication information and the multiplexing manner, resource location information occupied to transmit the scheduling assignment information. The UE can then transmit the scheduling assignment information based on the resource location information occupied by the scheduling assignment information.

Device-to-device (D2D) communication is a communication mode in which two peer terminals directly communicate with each other without using a base station. The base station may perform resource configuration, scheduling, coordination, and the like, to assist in direct communication between the terminals. The D2D communication includes two characteristics: discovery and communication. The discovery means that a terminal periodically broadcasts information, so that a terminal surrounding the terminal may detect the information and discover the terminal. The communication means that direct data transmission is performed between terminals, and a mechanism of scheduling assignment (SA)+data is used. The SA is used to indicate status information of data sent by a transmit end, and the status information includes time-frequency resource information, modulation and coding scheme (MCS) information, frequency hopping indication information, timing advance information, and receiving group ID information, and the like of the data, so that a receive end can receive service data based on the formation indicated by the SA. The data is service data sent by the transmit end based on the time-frequency resource information indicated by the SA and in a format indicated by the SA.
If a terminal that performs D2D communication is within a coverage area of the base station, the base station configures a transmission resource pool (for example, an SA resource pool and a data resource pool) for the terminal, so that the terminal performs data transmission of the D2D communication. The terminal may perform D2D transmission by using a time-frequency resource configured by the base station for the terminal in the resource pool, or may independently and randomly select a time-frequency resource from a configured resource for D2D transmission.
The Internet of Vehicles (IOV) may implement interconnection and interworking of vehicle-to-vehicle (V2V), vehicle-to-roadside (V2R), vehicle-to-Internet (Vehicle-to-Internet, V2I), vehicle-to-human (V2H), and the like. Currently, a cellular network technology is used for V2V communication in the Internet of Vehicles, so that a base station may be fully used to dynamically schedule a transmission resource, a communication conflict probability is reduced, and a problem of delay uncontrollability is resolved. In Internet of Vehicles based on base station assistance, a base station mainly performs transmission resource configuration, interference coordination, and the like. Because vehicle-to-vehicle communication in an Internet of Vehicles system is also terminal-to-terminal communication, the V2V communication may be considered as the D2D communication.
However, not all D2D communications technologies are applicable to the V2V communication. For example, a method for indicating an SA time-frequency resource by the base station in D2D communication is not applicable to the V2V communication. There are a plurality of multiplexing manners for the SA and the data in the V2V communication, and the multiplexing manner is used to describe a relationship between a time-frequency resource for transmitting the SA and a time-frequency resource for transmitting the data. For example, the multiplexing manner is used to indicate whether the SA and the data are transmitted in different subframes or in a same subframe, or the like. However, the plurality of multiplexing manners for the SA and the data do not exist in the D2D communication. Therefore, if the method for indicating the SA time-frequency resource by the base station in the D2D communication is still used in the V2V communication, a resource occupied to transmit SA information cannot be accurately indicated or obtained, and transmission performance is affected.

Scheduling assignment information transmission method and system, and device


Scaffolding for supporting one or more rooftop workers engaged in installing roofing materials such as roof shingles on an inclined roof.

The present invention relates to supports and particularly to scaffolding for supporting one or more rooftop workers engaged in installing roofing materials such as roof shingles.
Slanted roofs are commonly used in construction of residential and in some commercial buildings with the roofs covered by shingling of one kind or another. During the course of installing or repairing shingles on such slanted roofs, workmen require supporting scaffolding that can be positioned and repositioned as work progresses.
The prior art reveals several patents disclosing roofworker support structures including U.S. Pat. No 5,908,083 which discloses a pair of peak adjustable elongate assemblies deployable independently in substantially parallel position. Each elongate assembly includes an overpeak member and an adjustment member for the overpeak member, as well as one or more crosspiece support members for supporting a crosspiece or plank. In this arrangement, the crosspiece support members are in fixed locations on the elongate assembly so that the plank must be repositioned on another set of cross piece support members as work progress along the roof surface. In addition, support structures lie on the roof so as to require movement of the support structures laterally along the roof surface for installation of shingles in the space occupied by the support structures.
U.S. Pat. No 5,624,006 discloses a support apparatus for use on an inclined roof consisting of a ladder which hooks at one end to the roof ridge and a support frame secured to the ladder. The ladder lies directly on the roof surface, and the entire assembly must be positioned and repositioned along the length and breadth of the roof to complete a roofing job.
U.S. Pat. No 3,842,934 discloses an apparatus for laying roofing materials on a sloping roof comprising spaced load supporting members each having a load supporting carriage. The spaced carriages support the ends of a plank extending across the roof surface. The carriages advance up the load supporting members by means of a conventional ratchet jack mechanism. The load supporting members are spaced above the roof surface. The supporting members and carriages appear as a relatively heavy and rigid assembly so as to maintain spacing of the support members above the roof without deflecting onto the surface under a workman's weight thereby impeding the laying of materials. The assembly of supporting members and carriages constitutes a bulky and heavy arrangement that must be hand carried up a ladder and pushed up along a roof incline into working position with one end over a ridge peak. In addition, the design is also limited by a relatively slow dual jacking action to advance a supporting plank up a roof incline.
There is need for a lightweight, easy to place roof supporting structure spaced from the roof surface to allow for laying of material under the support, with means for mounting a workman's plank that can quickly move upward along the roof surface, and with a safety block plate for securing the workman's plank in any desired position on the roof incline. There is need to provide spacers beneath the support structure so that light weight support components can be used without deflection under a workman.


A system including a base station and a plurality of stations. The base station is configured to estimate bandwidths used by the plurality of stations based on packets transmitted by the plurality of stations during a first period. The base station is further configured to selectively allocate timeslots to the plurality of stations for transmission of packets to the base station during a second period following the first period. Durations of the timeslots are based on the estimated bandwidths. The plurality of stations are configured to transmit packets to the base station in the timeslots during the second period.

1. Field of the Invention
The present invention relates to information communication systems. More particularly, the present invention relates to a system and method for estimating bandwidth requirements of and allocating bandwidth to communication devices operating in a network.
2. Background Information
A conventional wireless local area network (WLAN) is based on a cellular architecture in which the system is divided into cells. Each cell, referred to as a Basic Service Set (BSS), is controlled by a Base Station, referred to as an Access Point (AP). The APs of the cells are connected to each other through a suitable type of backbone, referred to as a Distribution System (DS). The entire interconnected WLAN, including the different cells, their respective APs and the DS is referred to as an Extended Service Set (ESS).
One or more clients or stations within a cell can communicate using a carrier sense multiple access with collision avoidance (CSMA/CA) protocol for medium access control. In a CSMA/CA protocol, a station desiring to transmit senses the channel. If the channel is busy (i.e., some other station is transmitting), then the station will defer its transmission to a later time. If the channel is sensed to be free at that time, then the station is allowed to transmit. The CSMA/CA protocol works well when the channel is not heavily loaded, allowing the stations to transmit with minimal delay. However, two or more stations may transmit at the same time, causing collisions, if the stations sense that the channel is free and decide to transmit at once.
To overcome such problems, conventional WLANs use a collision avoidance mechanism with a positive acknowledgment scheme. In such a scheme, a station desiring to transmit will sense the channel. If the channel is busy e the station will defer transmission. If the channel is free for a specified amount of time, then the station (the "sending station") is allowed to transmit. The receiving station will check the cyclic redundancy code (CRC) of the received frame and send an acknowledgment frame (ACK). If the sending station receives the ACK, then no collision has occurred. However, if the sending station does not receive the ACK, then the sending station will retransmit the frame until it is acknowledged or thrown away after a given number of retransmissions. However, in a WLAN, all stations may not be able to hear each other. Thus, a station may desire to transmit and senses the channel to be free, although the channel may not necessarily be free.
To reduce the probability of two or more stations colliding because they cannot hear each other, conventional WLANs use a virtual carrier sense mechanism. In such a mechanism, a station that desires to transmit will first transmit a short control frame, referred to as a Request to Send (RTS). The RTS includes the source, the destination and the duration of the frame to be transmitted and the respective ACK. If the channel is free, the destination station will respond with a response control frame referred to as a Clear To Send (CTS). The CTS includes the same duration information as the RTS. All stations receiving either the RTS and/or CTS will set their respective virtual carrier sense indication, referred to as Network Allocation Vector (NAV), for the given duration, and will use this information when sensing the channel. The virtual carrier sense mechanism reduces the probability of a collision in the receiver area by a station that cannot be heard by the transmitter to the short duration of the RTS transmission, because the station will hear the CTS packet and "back off" the channel until the end of the transaction. A backoff method is used to resolve contention between different stations desiring access to the channel. A binary exponential backoff algorithm requires each station, when the channel is busy, to choose a random number between zero and a given number, and wait for this number of time slots before accessing the channel, checking whether another station has accessed the channel before transmitting.
The above discussion applies to the Distributed Coordinated Function (DCF) mode. In the DCF node, there is no central control, and stations compete for transmission time. In contrast in the Point Coordinated Function (PCF) mode, the AP polls the stations, inquiring whether any of the stations have frames to transmit. Since transmission order is completely controlled by the AP in PCF mode, no collisions occur. In PCF mode, the AP broadcasts a beacon frame periodically. The beacon frame contains various system parameters. The beacon frame also invites stations to sign up for polling service. Once a station has signed up for polling service at a certain rate, the station is allocated a certain fraction of the total bandwidth available for transmission.
Conventional WLANs use an interframe time interval to allow the DCF and PCF modes to coexist within a cell. After a frame is transmitted, a given amount of dead time is required before any station can transmit a frame. The shortest interval is the Short InterFrame Spacing (SIFS) time. SIFS is used to allow stations in a single dialog the chance to go first, including letting the receiver send a CTS to respond to a RTS, letting the receiver send an ACK for a frame fragment or full data frame and letting the sender of a fragment burst transmit the next fragment without having to send a RTS again. There is always exactly one station that is entitled to respond after a SIFS interval. If the station fails to make use of its chance to transmit and a PCF InterFrame Spacing (PIFS) time elapses (equal to SIFS plus a specified slot time), the AP may send a beacon frame or a poll frame. Such a mechanism allows a station sending a data frame or frame fragment sequence to finish its frame without other stations interfering, but gives the AP a chance to access the channel when the previous sender is done without having to compete with the stations. If the AP has nothing to transmit and a DCF InterFrame Spacing (DIFS) time elapses (equal to PIFS plus one timeslot), any station may attempt to acquire the channel to send a new frame. Contention rules apply, and the binary exponential backoff algorithm may be needed if a collision occurs. The longest time interval is the Extended InterFrame Spacing (EIFS) time interval. EIFS is used only by a station that has received a bad or unknown frame to report the bad frame.
Thus, to allocate bandwidth in conventional WLANs, the stations must contend with substantial processing overhead to compete for available bandwidth when there is no central control (e.g., in DCF mode), or must make requests for bandwidth to the AP and wait for the allocation via polling (e.g., in PCF mode). Consequently, both the DCF and PCF modes reduce throughput, especially in upstream traffic, due to the overhead involved with allocating bandwidth amongst the stations.

This patent is subject to a terminal disclaimer.

System and method for estimating bandwidth requirements of and allocating bandwidth to communication devices operating in a network


There is provided a gas sensor element, including a solid electrolyte layer, a pair of sensor electrodes arranged on a front side of the solid electrolyte layer, a pair of sensor leads arranged on a rear side of the solid electrolyte layer and connected to the respective sensor electrodes; and insulating layers, one of which is arranged between one of the sensor leads and the solid electrolyte layer and the other of which is arranged between the other sensor lead and the solid electrolyte layer. The sensor electrodes have rear end portions located on the insulating layers and overlapping front end portions of the sensor leads, respectively. The sensor leads are denser than the sensor electrodes and have front ends located in the same positions as or positions rear of front ends of the insulating layers, respectively. There is also provided a gas sensor with such a gas sensor element.

The present invention relates to a gas sensor element and a gas sensor having the gas sensor element.
Hereinafter, the terms "front" and "rear" are used with respect to the axial direction of a gas sensor or the longitudinal direction of a solid electrolyte layer of the gas sensor for purposes of description. These terms are illustrative and are not intended to limit the scope of the present invention.
There has been used a gas sensor for combustion control of an internal combustion engine. The gas sensor includes a sensor element capable of outputting a detection signal responsive to the concentration of a specific gas component in gas under measurement, that is, exhaust gas flowing through an exhaust pipe of the internal combustion engine. Japanese Laid-Open Patent Publication No. 2010-38904 discloses one such type of sensor element that has a plate-shaped solid electrolyte layer formed predominantly of zirconia, a pair of electrodes arranged on a front side of the solid electrolyte layer, insulating layers formed on a rear side of the solid electrolyte layer and a pair of leads arranged on the insulating layers and connected to the electrodes, respectively, so as to generate a detection signal responsive to the concentration of the specific gas component (e.g. oxygen) in the exhaust gas in accordance with a potential difference developed between the electrodes by the exhaust gas and reference gas (air) and output the detection signal to an external control device. In this gas sensor element, it is necessary that each of the electrodes have a porous structure so as to take in and allow diffusion of the exhaust gas; whereas it is preferable that each of the leads has a dense structure so as to show low electrical resistance for use in signal transmission between the electrodes and the external control device.


Various systems and methods may benefit from determination of environmental signatures in recordings. For example, such signatures may aid forensic analysis and alignment of media recordings, such as alignment of audio or video recordings. A method can include extracting electric network frequency signals from an image sequence of a video recording or an audio recording. The method can also include synchronizing the video recording or the audio recording with at least one other datum based on the electric network frequency signals.

Field
Various systems and methods may benefit from determination of environmental signatures in recordings. For example, such signatures may aid forensic analysis and alignment of media recordings, such as alignment of audio or video recordings.
Description of the Related Art
Advancement in multimedia technologies has given rise to proliferation of such media recording devices as voice recorders, camcorders, digital cameras, and the like. A huge amount of digital information created using such devices can be stored on disks or uploaded on such social media platforms. Metadata describing such important information as the time and the place of recording may be manually added or can be embedded to a media recording using built-in clocks and global positioning system (GPS) in the recording devices. However, digital tools can be used to modify the stored information.
Forensic tools can be used to authenticate multimedia recordings using a signature, known as Electrical Network Frequency (ENF) signal, emanated from power networks. ENF is the supply frequency of electric power in power distribution networks, and its nominal value is 50 or 60 Hz depending on the geographic location. A property of the electric network frequency signal is that its value fluctuates around the nominal value: on the order of approximately 50-100 mHz in the United States. These fluctuations are due to variations in the load on the power grid and generally can be considered as random. Such randomly varying electric network frequency signal can be embedded in multimedia recordings due to the electromagnetic interference from nearby power lines in audio, and invisible flickering of electric powered indoor lightings.
Electric network frequency fluctuations based forensic analysis can thus be used for multimedia authentication tasks as time-of-recording estimation, timestamp verification, and clip insertion/deletion forgery detection. Electric network frequency can fluctuate due to dynamic changes in load demand and power supply, and these fluctuations travel over the power lines with a finite speed.
The electric network frequency signal can be extracted from power signals measured from a power outlet using a step-down transformer and a simple voltage divider circuit. The power signal is divided into time-frames, and frequency estimation algorithms are applied on each frame to determine its dominant frequency, thus estimating the instantaneous electric network frequency signal. The importance of the electric network frequency for multimedia forensics emerges because the electric network frequency can also be present in audio or video recordings due to electromagnetic influences in the place of recording. The electric network frequency variations extracted from a clean power signal match with the electric network frequency variations extracted from an audio signal recorded at the same time and in the same power grid as the power signal.
Digital video cameras have become increasingly popular, thanks to the rapid development of hardware and software technologies. As the amount of video data grows drastically every day, new applications arise for which multiple pieces of audio-visual data need to be analyzed and processed together.
When an event is recorded simultaneously by multiple independent video cameras and possibly from a variety of angles, combining the information in these videos may provide a better presentation and novel experience of the event than each recording alone. For example, a dynamic scene may be reconstructed that allows people to choose from different viewing angles of an event during playback. A video sequence of high space-time resolution can be obtained by combining information from multiple low-resolution video sequences of the same dynamic scene. Synchronization is a fundamental issue to enable these and other applications involving multiple pieces of audio-visual data, namely, the task of temporally aligning video or other multimedia signals.

Techniques to extract ENF signals from video image sequences exploiting the rolling shutter mechanism; and a new video synchronization approach by matching the ENF signals extracted from soundtracks and image sequences


A system may be configured to identify pedigree information associated with a drug. The system may include a structure with an RFID reader and a bar code reader. The system may also include a master control unit configured to receive product identification data from the RFID reader and the bar code reader. The system may also include a database system configured to store pedigree information associated with medicament containers. The system may also include a display unit disposed proximate to the support structure, and the display unit may be configured to receive and display the pedigree information to a user. In response to the movement of a medicament container proximate the RFID reader or the bar code reader, the master controller may submit a query to the database system, receive the pedigree information, and cause the display unit to display a portion of the pedigree information to the user.

According to the FDA, counterfeit pharmaceutical drugs pose a significant threat to the public safety and to the integrity of the overall drug supply chain. Drug counterfeiting has increased in recent years, which is potentially related to the increased number of access points that exist in the supply chain for many of these drugs. Prescription pharmaceutical drugs are typically transferred between a number of different parties before they are eventually dispensed to a consumer. For example, a drug may be produced by a manufacturer, then handed off to a distributor, and then delivered to a pharmacy or other retailer before finally being dispensed to a consumer. With each of these transfers, and with every additional handler of the drugs, there is an inherent risk of potential foul play.
In an attempt to prevent or at least minimize drug counterfeiting and other improper drug transfers, many federal and state government agencies now require, or may soon require, that records of these drug transfers be tracked and maintained—essentially creating a chain of custody for the drug from the time it is produced until it reaches the consumer. This chain of custody information is often referred to as the pedigree of a drug, and it was traditionally maintained via inefficient paper documentation. Paper-based drug pedigrees allowed agencies to more efficiently track and prosecute counterfeiting activities, but did little to prevent such activities due to intrinsic delays associated with a paper-based system. More recently, the pedigree information is increasingly being stored in electronic form. These electronic records are often referred to as the electronic pedigree, or e-pedigree, of a drug.


Provided is a method for producing a silica aerogel blanket having high thermal insulation and high strength, wherein an acicular metal-silica composite is added to a step of preparing a silica precursor solution during the production of the silica aerogel blanket to produce a silica aerogel blanket having characteristics of high thermal insulation, high strength, high thermal resistance and low dust.

A silica aerogel blanket is a product having strengthened structure and greatly improved usability by introducing an inorganic fiber into aerogel, and is used in various industrial fields due to very low thermal conductivity thereof.
However, there is a tendency in that the thermal conductivity of the silica aerogel blanket is rapidly increased at a high temperature of about 400° C. or higher, and at an ultra-high temperature of 650° C. or higher, severe shrinkage thereof occurs since the temperature exceeds the melting temperature of silica, which is the main component of the silica aerogel blanket.
Due to such problems, there is a disadvantage in that the silica aerogel blanket can be used only at a temperature of 600° C. or lower. In order to overcome the disadvantage, a method of increasing the overall density of the aerogel blanket by introducing an inorganic additive having a high specific gravity or increasing the density of a fiber used has been used. When the density of the aerogel blanket is increased, severe shrinkage thereof is prevented even at an ultra-high temperature, thereby preventing a rapid increase in thermal conductivity.
When the density of the aerogel blanket is increased through the above-mentioned method, it is possible to slow down the increase in thermal conductivity after heat treatment. However, there is a problem in that thermal conductivity at room temperature before the heat treatment is noticeably increased due to the influence of the inorganic additive and the fiber having a high density.
Therefore, in order to increase the utilization of an aerogel blanket and to broaden the usage range thereof, there is a need for the development of a method capable of increasing the density of the aerogel blanket while minimizing the deterioration of the thermal insulation performance thereof.

Method for producing silica aerogel blanket having high thermal insulation and high strength


A transporting and positioning device for tool magazine of a bridge type machine tool comprises a pair of parallel guide-ways on a plate, a seat slidably mounted on the guide-ways for supporting the tool magazine, a drive mechanism including a cylinder, an extendable positioning shaft, a connection block adjacent the plate the connection block including a top hole and being fixed to the table, and a second cylinder having an extendable second positioning shaft; In an operating state of the machine tool, the second positioning shaft is actuated by the second cylinder to project an adjustable distance through the plate to urge against the seat for fastening the seat and the tool magazine. A tool change is performed after fastening the positioning shaft in the hole. The invention is also applicable to EDM.

The present invention relates to machine tools and more particularly to a transporting and positioning device for tool magazine of a bridge type machine tool with improved characteristics.
A conventional machine tool of bridge type is shown in FIG. 1 wherein a spindle 1 is provided adjacent a side of a cross-rail 2. The spindle 1 is able to move along a Y axis with respect to the cross-rail 2 and a Z axis with respect to itself. A table 3 is able to move along an X axis. With such three-axis movement, the machine tool can work on a work piece (not shown). Two columns 4 at both ends of the cross-rail 2 do not interfere with the movement of the spindle 1 along the Y axis. Hence, a tool magazine 5 can be provided adjacent one of the columns 4. The spindle 1 can move to a position above the tool magazine 5 for tool change.
Another conventional bridge type machine tool is shown in FIG. 2 wherein a spindle 6 is provided on a cross-rail 7 and is moveable along a Y axis defined by the cross-rail 7 and along a Z axis with respect to itself. A table 8 is able to move along an X axis. A travel distance of the spindle 6 does not enable it to access a tool magazine since the movement of the spindle 6 is defined in the cross-rail 7. Once the tool magazine is disposed in the travel distance of the spindle 6 it will interfere with a normal operation of the spindle 6. A solution to this problem is to dig an opening in one of columns 9 for forming a tool magazine 10 therein. In a tool change operation, a cylinder is activated to push the tool magazine 10 to a position within the travel distance of the spindle 6. Next, the spindle 6 is activated to move to a position above the tool magazine 10 for tool change. However, the prior art suffered from several disadvantages. For example, the opening in the column 9 will adversely affect a structural strength of the column 9. Further, the number of tools contained in the tool magazine 10 is limited due to a narrow space in the opening. A prolonging of the length of the cross-rail 7 can decrease a harmonic frequency of the machine tool, resulting in a lower rigidity of the whole construction. A proposal is to form the tool magazine 10 in an outside position rather than in the column 9. However, an additional cylinder is required to push the tool magazine 10 to a position within the travel distance of the spindle 6. Such cylinder is typically not precise in positioning and lacks moving stability. Hence, it is not reliable. An additional servo driving axis without the above drawback of the cylinder can be used to push the tool magazine 10. However, it can significantly increase a manufacturing cost. Hence, a need for improvement exists.
It is therefore an object of the present invention to provide a transporting and positioning device for tool magazine of a machine tool. The transporting and positioning device is activated by a servo driving system of the machine tool without the installation of an additional drive device. By utilizing the present invention, it is possible of effecting a quick, high precision positioning of the tool magazine and reducing the manufacturing and maintenance costs.
In one aspect of the present invention, there is provided a machine tool comprising, in combination two side columns; a cross-rail interconnecting the columns, the cross-rail having a lengthwise channel; a spindle moveable along the channel and along a lengthwise direction of itself, the spindle having a changeable element at its open end; a moveable table under the cross-rail; a servo driving system below the table; a magazine containing a plurality of elements; and a transporting and positioning device including a plate at a side of one of the columns, a pair of parallel guide-ways on the plate, a sliding seat mounted on the guide-ways for supporting the magazine thereon, a drive mechanism including a cylinder on a side of the seat, a positioning shaft, a connection block adjacent one side of the plate by a predetermined distance, the connection block including a top hole and being fixed to the table, and a second cylinder having a second positioning shaft; wherein in an operating state of the machine tool, the second positioning shaft is actuated by the second cylinder to project an adjustable distance through the plate to urge against the seat for fastening the seat and the tool magazine; and in a tool change, slide the seat along the guide-ways by activating the cylinder until the magazine is below the cross-rail, activate the servo driving system to drive both the table and the connection block to move along a predetermined direction until the hole is aligned with the positioning shaft, drive the positioning shaft into the hole for fastening, activate the spindle to move along the channel until the spindle is aligned with the magazine and within an operable distance so as to change the element of the spindle with one of the elements of the magazine.
In another aspect of the present invention, each of the element of the spindle and the elements of the magazine is a tool.
In still another aspect of the present invention, each of the element of the spindle and the elements of the magazine is an attachment head.
In a further aspect of the present invention, there is provided an EDM comprising, in combination: two side columns; a cross-rail interconnecting the columns, the cross-rail having a lengthwise channel; a ram moveable along the channel and along a lengthwise direction of itself, the ram having a changeable tool at its open end; a moveable table under the cross-rail; a servo driving system below the table; a magazine containing a plurality of tools; and a transporting and positioning device including a plate at a side of one of the columns, a pair of parallel guide-ways on the plate, a sliding seat mounted on the guide-ways for supporting the magazine thereon, a drive mechanism including a cylinder on a side of the seat, a positioning shaft, a connection block adjacent one side of the plate by a predetermined distance, the connection block including a top hole and being fixed to the table, and a second cylinder having a second positioning shaft; wherein in an operating state of the machine tool, the second positioning shaft is actuated by the second cylinder to project an adjustable distance through the plate to urge against the seat for fastening the seat and the tool magazine; and in a tool change, slide the seat along the guide-ways by activating the cylinder until the magazine is below the cross-rail, activate the servo driving system to drive both the table and the connection block to move along a predetermined direction until the hole is aligned with the positioning shaft, drive the positioning shaft into the hole for fastening, activate the ram to move along the channel until the ram is aligned with the magazine and within an operable distance so as to change the tool of the ram with one of the tools of the magazine.

Transporting and positioning device for tool magazine of machine tool

Industrial Technology Research Institute


The present invention provides a hole profile gage comprising a probe that senses deviations in the contour of the inner surface of a bore while it is retracted through the bore. The profile gage includes a processing unit that samples the output from the probe, develops a profile for the hole, and evaluates whether the profile is within predetermined tolerance limits. In a preferred embodiment, the probe comprises a split ball probe coupled with a transducer. In use, the probe is retracted through the bore by a spring coupled with a damping device.

The invention provides a portable profile gage that senses the profile of a bore drilled through one or more layers of material and determines whether the bore is within required tolerance limits. The profile gage has great advantages over devices previously known in the art as it is hand held, easy to use, and provides a quick and accurate determination of whether a hole meets the required specifications.
The invention is particularly useful in operations where holes for rivets or other fasteners are drilled through one or more layers of material. Drilling holes through layers of different materials, and especially through stacks of composite materials and titanium, can be troublesome as the drill may chip or gouge one layer as it enters a second layer. Most fasteners are able to endure some flaws in the side surfaces of the drilled holes, but typical engineering specifications require that the overall sidewall surface of the hole be within 70-90% of the desired specification in order to ensure adequate support and resistance to shear forces on the shank of the fastener. Less than 70% contact between the fastener and the walls of the bore can result in lower joint fatigue endurance. If the hole is not within the desired tolerance range, corrective action must be taken before the fastener is inserted.
In automated drilling operations, it is difficult for the operator to determine accurately whether the inner surfaces of a bore are within acceptable tolerances simply by inspection. Some gaging device is necessary to provide an accurate profile. U.S. Pat. No. 4,290,204 to Possati describes a plug gage with "feelers" that move radially and contact the internal walls of a bore. U.S. Pat. No. 4,112,355 to Gibson et al. discloses a capacitance measuring device for detecting the quality and fit of tapered fastener holes. U.S. Pat. No. 3,757,569 to O'Brien et al. discloses a flaw or chip detector in which the gaging head is a roller element that moves over the internal surface of the bore. These devices are complicated and work in a different manner from the device of the present invention. The present invention provides a device that is easy and simple to operate and that quickly and accurately determines the profile of a hole and whether the hole is within prescribed tolerance limits.


The invention relates to the addition of α-methyl styrene, isobutanol and/or isopropanol to reduce vapor pressure, improve k-factor, enhance the solubility of the blowing agent in the premix and/or improve the processing characteristics of polyurethane and polyisocyanurate closed-cell foams prepared with a blowing agent comprising a hydrofluorocarbon selected from the group consisting of 1,1,1,3,3-pentafluoropropane, 1,1,1,2-tetrafluoroethane, 1,1,2,2-tetrafluoroethane, and mixtures thereof.

The class of foams known as low density rigid polyurethane or polyisocyanurate foam has utility in a wide variety of insulation applications including roofing systems, building panels, refrigerators and freezers. The methods of producing polyurethane and polyisocyanurate foams are generally known and consist in general of the reaction of an organic polyisocyanate and a polyol or mixture of polyols in the presence of a volatile blowing agent, which is caused to vaporize by the heat liberated during the reaction of isocyanate or isocyanurate and polyol. This reaction can be enhanced through the use of amine and/or other catalysts as well as surfactants. The catalysts ensure adequate curing of the foam, while the surfactants regulate and control cell size.
The foam industry has historically used liquid fluorocarbon blowing agents such as trichlorofluoromethane (CFC-11) and 1,1-dichloro-1-fluoroethane (HCFC-141b) because of their ease of use in processing conditions. Fluorocarbons act not only as blowing agents by virtue of their volatility, but also are encapsulated or entrained in the closed cell structure of the rigid foam and are the major contributor to the low thermal conductivity properties of rigid urethane foams. The escape of certain fluorocarbons, most notably chlorofluorocarbons, to the atmosphere is now recognized as potentially contributing to the depletion of the stratospheric ozone layer and to global warming. In view of the environmental concerns with respect to chlorofluorocarbon blowing agents, it is now generally accepted that it would be more desirable to use hydrochlorofluorocarbons (HCFCs) or hydrofluorocarbons (HFCs) rather than the chlorofluorocarbons. Exemplary hydrofluorocarbons suitable for use as blowing agents in the preparation of polyurethane and polyisocyanurate foams are 1,1,1,3,3-pentafluoropropane, 1,1,1,2-tetrafluoroethane and 1,1,2,2-tetrafluoroethane (known in the art as HFC-245fa, HFC-134a, and HFC-134, respectively). These materials, however, possess a lower boiling point and a correspondingly higher vapor pressure than the prior art materials. This difference becomes significant when any of HFC-245fa, HFC-134a or HFC-134 are incorporated into the B-side of a foam formulation that is either transported in or used directly from a low pressure rated container.
The use of a fluorocarbon as the preferred commercial expansion or blowing agent in insulating foam applications is based in part on the resulting k-factor associated with the foam produced. K-factor is defined as the rate of transfer of heat energy by conduction through one square foot of one inch thick homogenous material in one hour where there is a difference of one degree Fahrenheit perpendicularly across the two surfaces of the material. As is generally known in the art, the cell gas composition of the foam at the moment of manufacture does not necessarily correspond to the equilibrium gas composition after aging or sustained use. The gas in a closed cell foam frequently exhibits compositional changes as the foam ages leading to such known phenomena as increase in thermal conductivity or loss of insulation value (both measured in terms of k-factor) and thermal aging. Since the utility of closed-cell polyurethane-type foams is based, in part, upon their thermal insulation properties, it would be advantageous to identify materials which lower the k-factor of foams and reduce thermal aging of the foams over time.
Methods for improving the k-factor and/or thermal aging characteristics of polyurethane foam are disclosed in U.S. Pat. Nos. 5,696,306 and 5,837,742. There remains a need in the art for polyurethane and polyisocyanurate foams prepared from a blowing agent comprising a hydrofluorocarbon selected from the group consisting of HFC-245fa, HFC-134a, HFC-134 and mixtures thereof, which foams have improved processibility, k-factor and/or thermal aging characteristics. The instant invention meets this need by providing additives that reduce the vapor pressure of HFC-245fa and HFC-134a and/or reduce the k-factor of foams produced from blowing agents comprising these hydrofluorocarbons.

Hydrofluorocarbon blown foam and method for preparation thereof


An optical module is provided with a ferrule an optical fiber which penetrates a center thereof along an axis direction of the ferrule, a member inserted with the ferrule, a sealed container connected to the member and having an optical system which optically couples to the optical fiber, and a resin portion encapsulating the member and the sealed container. A communication path includes a first communication passage between the ferrule and the member, a space where the optical system and the optical fiber confront each other, and a second communication passage between the ferrule and the member, where the first and second communication passages are mutually independent.

This application claims the benefit of a Japanese Patent Application No. 2001-133675 filed Apr. 27, 2001, in the Japanese Patent Office, the disclosure of which is hereby incorporated by reference.
1. Field of the Invention
The present invention generally relates to optical modules and optical module producing methods, and more particularly to an optical module, having an optical connector, which is detachably and optically coupled and is covered by a molded resin for protection at the time of production, and to an optical module producing method for producing such an optical module.
2. Description of the Related Art
In optical communication apparatuses and information processing apparatuses which process optical signals, there are demands to realize a high-density optical signal transmission at a high speed and a high capacity. On the other hand, there are also demands to reduce the size and cost and to simplify the structure of a transmitter section and a receiver section of a terminal equipment which transmits and receives the optical signal. Hence, there are similar demands with respect to various kinds of optical modules.
In the optical module which is coupled to an optical fiber of the transmission line, it is desirable that the optical module is detachably connected directly by an optical connector. Hence, the so-called pig-tail type optical module, which has the optical connector at a tip end of an optical fiber having a suitable length, is popularly used. However, the provision of the optical fiber introduces various problems.
For example, when assembling the optical module by an automatic assembling process, the provision of the optical fiber interferes with the full automation of the assembling process. In addition, when transporting the optical module, it is necessary to accommodate the optical module within a transporting case and to handle the optical module with care. Furthermore, when mounting a main body of the optical module within an apparatus, it is necessary to take appropriate measures such as mounting the optical fiber by winding the optical fiber to a predetermined diameter.
In view of the above, it is possible to effectively reduce the size of the optical module, by providing an optical connector section without via an optical fiber, as shown in a cross sectional view of FIG. 1.
An optical module 1 has a projecting ferrule 2, for an optical connector, provided with an optical fiber at a central portion on a tip end portion on the left side of the optical module 1 in FIG. 1. The periphery of the ferrule 2 fits in a first cylindrical member 3, and the periphery of the first cylindrical member 3 fits in a second cylindrical member 4. An end surface of the second cylindrical member 4 is connected to an end surface of an optical device 5 which is made of a sealed container. An optical element, such as a laser diode which is used as a light emitting element, is provided within the optical device 5.
A plurality of terminals 6 for connecting to electrical circuits is provided on the right side of the optical device 5 in FIG. 1. The terminals 6 are connected to a circuit board 7 having various electrical circuits. Terminals 8 for connecting to an external circuit are provided on both sides of the circuit board 7.
A synthetic resin molded portion 9 covers, that is, encapsulates, the periphery of the optical module 1, excluding the tip end portion of the ferrule 2 and the ends of the terminals 8, to form the optical module 1.
The synthetic resin molded portion 9 has an engaging part 11 which projects on both sides in a direction perpendicular to an axis direction of the ferrule 2 and the first cylindrical member 3. The engaging part 11 includes a sloping surface 12 located on a left side in FIG. 1, an engaging surface 13 perpendicular to the axis direction located on the right of the sloping surface 12, a flat guide portion 14 located on the left of the sloping surface 12, and a constricted portion 15 located on the right of the engaging surface 13. These elements of the engaging part 11 form a connector section 16 of the optical module 1.
In FIG. 1, the cross section of the synthetic resin molded portion 9 is shown along the solid line to facilitate understanding of the positional relationship of the optical device 5 and the circuit board 7.
FIGS. 2A and 2B respectively show a plan view and a cross sectional view of an optical connector 21 of an optical fiber cord which forms an optical fiber transmission line that connected to the optical module 1. In the optical connector 21, a cylindrically coiled spring 24 having a slit 23 in the axis direction, and also referred to as a split sleeve, is fit into a central penetration hole in a synthetic resin molded housing 22. A ferrule 25 is press-fit within the cylindrically coiled spring 24 so as to push and spread the diameter of the cylindrically coiled spring 24.
A holder 26 is press-fit and connected to the left side of the ferrule 25 in FIGS. 2A and 2B. An optical fiber cord 27 is fixed to the holder 26. In addition, the optical fiber of the optical fiber cord 27 penetrates the center of the ferrule 25 and is connected to the ferrule 25. The end of the optical fiber is exposed at the end portion of the ferrule 25, and is optically polished.
A compressed coil spring 28 is inserted between the housing 22 and the holder 26. The compressed coil spring 28, together with the holder 26, pushes against the ferrule 25 and urges the ferrule 25 towards the rightward direction in FIGS. 2A and 2B.
A pair of engaging leaf springs 31 which project towards the axis direction are provided in parallel on the right side of the housing 22 in FIGS. 2A and 2B. Each engaging leaf spring 31 has an engaging projection 32 on a tip end thereof, and a guide portion 33 on an inner side of the engaging projection 32. The engaging projections 32 of the pair of engaging leaf springs 31 confront each other, and the guide portions 33 of the pair of engaging leaf springs 31 confront each other.
A sloping surface 34 and an engaging surface 35 which is perpendicular to the axis direction are formed on the tip end of the engaging projection 32. The engaging projection 32 and the guide portion 33 are separated by an intermediate space or gap which extends in a direction perpendicular to the paper in FIGS. 2A and 2B.
The optical connector 21 is known as an EZ type optical connector, and the diameter of the ferrule 25 is 1.25 mm. The housing 22 is made of a synthetic resin having mechanical resilience. The cylindrically coiled spring 24 is made of a resilient material such as zirconia ceramics or metal. The ferrule 25 is made of zirconia ceramics. The holder 26 is made of a molded synthetic resin, and the compressed coil spring 28 is made of a known metal coil.
When optically connecting the optical module 1 and the optical connector 21, the engaging projection 32 of the optical connector 21 is fit over the connector section 16 of the optical module 1, as shown in FIG. 3A which shows the optical connector 21 in cross section.
In other words, the optical connector 21 is pushed so that the guide portions 14 fit into the intermediate spaces of the upper and lower engaging projections 32. Hence, the sloping surfaces 12 and 34 contact each other, and the engaging leaf springs 31 of the optical connector 21 are spread on both sides against the spring force by this contact. As a result, the engaging projections 32 fit into the constricted portions 15 of the connector section 16 as shown in FIG. 3B, and the engaging leaf springs 31 are restored to their original states by the spring force.
During the above process, the tip end of the ferrule 2 fits into the cylindrically coiled spring 24 against the spring force of the cylindrically coiled spring 24. Hence, the tip end of the ferrule 2 is positioned to the central position of the cylindrically coiled spring 24, and the center of the tip end of the ferrule 2 matches the center of the tip end of the ferrule 25 of the optical connector 21. Furthermore, since the tip end of the ferrule 2 moves while compressing the compressed coil spring 28, the tip end of the ferrule 25 is pushed against the tip end of the ferrule 2 by the action of the compressed coil spring 28, to thereby realize a positive optical connection between the ferrules 2 and 25.
In addition, the guide portions 14 of the optical module 1 and the guide portions 33 of the optical connector 21 engage each other to maintain the optical module 1 and the optical connector 21 in a stable connected position. The engaging surfaces 35 of the optical connector 21 contact and engage the engaging surfaces 13 of the optical module 1, so as to positively prevent the optical module 1 and the optical connector 21 from slipping off from each other, and to provide the required optical coupling.
When disconnecting the optical module 1 and the optical connector 21, the engaging projection 32 on the tip ends of the engaging leaf springs 31 are spread with respect to the connector section 16 of the optical module 1, and the optical connector 21 is then pulled from the optical module 1. Since the optical connector 21 is small, the engaging leaf springs 31 are spread by use of an exclusive spreading jig.
Next, a description will be given of the method of assembling the ferrule 2 and the optical device 5 of the optical module 1, by referring to FIG. 4 which shows a cross section of these elements. In FIG. 4, the first cylindrical member 3 is press-fit and positioned on the periphery of the ferrule 2, and the second cylindrical member 4 is fit on the periphery of the first cylindrical member 3.
The end surface of the second cylindrical member 4 contacts and connects to the end surface of a sealed container of the optical device 5. A laser diode (LD, not shown) is provided as an optical element at a central bottom portion on the right end of the sealed container of the optical device 5. A light transmitting window is provided in the sealed container of the optical device 5 at a position confronting the optical fiber 36 which is provided at the center of the ferrule 2. A spherical lens 37 which forms a light transmitting optical system is mounted at the light transmitting window maintaining the sealed state of the sealed container of the optical device 5.
When assembling each of the above described elements, the second cylindrical member 4 and the first cylindrical member 3 are positioned along the axis direction so that the relative positional relationship via the spherical lens 37 optically match between the laser diode mounted on the sealed container of the optical device 5 and the end surface of the optical fiber 36 of the ferrule 2. In addition, the end surface of the second cylindrical member 4 and the end surface of the sealed container of the optical device 5 are positioned and fixed.
The above described positioning is made while measuring the optical output of the laser diode as the output from the optical fiber 36, so that the measured output becomes a maximum. In this state, a contact portion 38 between the first cylindrical member 3 and the second cylindrical member 4 and a contact portion 39 between the second cylindrical member 4 and the sealed container of the optical device 5 are welded by irradiating a welding laser beam from a plurality of symmetrical surrounding locations with respect to the center axis and instantaneously fixed with a satisfactory precision, without introducing positional error.
Thereafter, the circuit board 7 is connected to the above described assembled elements and placed in a cavity within a mold having a predetermined shape, so that the tip end of the ferrule 2 and the tip ends of the terminals 8 project by predetermined distances from the cavity. A synthetic resin such as an epoxy resin in a melted state is supplied into the cavity of the mold, and the synthetic resin molded portion 9 shown in FIG. 1 is removed from the mold after curing.
As shown in FIG. 1, the synthetic resin molded portion 9 covers the periphery of the first cylindrical member 3, the second cylindrical member 4 and the optical device 5, including the periphery of the ferrule 2. But when the melted synthetic resin is supplied into the cavity of the mold, volatile gas is generated from the melted synthetic resin which is at a temperature of 180xc2x0 C. and is in a high pressure state. This volatile gas enters into a minute gap between the first cylindrical member 3 and the second cylindrical member 4, a minute gap between the second cylindrical member 4 and the sealed container of the optical device 5, and a space between the ferrule 2 and the spherical lens 37 which confront each other.
When the synthetic resin molded portion 9 is removed from the mold, the volatile gas solidifies and forms a thin film on the surfaces of the optical fiber 36 and the spherical lens 37. An optical coupling loss occurs when such a thin film is formed, and consequently, a desired optical characteristic cannot be obtained.
Accordingly, it is a general object of the present invention to provide a novel and useful optical module and optical module producing method, in which the problems described above are eliminated.
Another and more specific object of the present invention is to provide an optical module and an optical module producing method, which can protect an optical coupling part so that the problems described above are eliminated, and a desired optical characteristic can be obtained.
Still another object of the present invention is to provide an optical module comprising a ferrule an optical fiber which penetrates a center thereof along an axis direction of the ferrule; a member inserted with the ferrule; a sealed container, connected to the member, having an optical system which optically couples to the optical fiber; a resin portion encapsulating the member and the sealed container; and a communication path including a first communication passage between the ferrule and the member, a space where the optical system and the optical fiber confront each other, and a second communication passage between the ferrule and the member, where the first and second communication passages are mutually independent. According to the optical module of the present invention, it is possible to use the communication path to supply a gas when molding the resin portion, so that fine particles of a volatile gas generated from the melted resin are prevented from adhering to the optical fiber and the optical system and forming a film when the volatile gas solidifies. For this reason, it is possible to prevent deterioration of the optical coupling between the optical fiber and the optical system, and the optical coupling part of the optical module is positively protected.
In the optical module, the first and second communication passages may be provided in at least one of the ferrule and the member.
A further object of the present invention is to provide an optical module producing method for producing an optical module which is provided with a ferrule an optical fiber which penetrates a center thereof along an axis direction of the ferrule, a member inserted with the ferrule, a sealed container connected to the member and having an optical system which optically couples to the optical fiber, a resin portion encapsulating the member and the sealed container, and a communication path including a first communication passage between the ferrule and the member, a space where the optical system and the optical fiber confront each other, and a second communication passage between the ferrule and the member, where the first and second communication passages are mutually independent and the optical module producing method comprises the step of (a) placing at least the ferrule and the member within a mold; and (b) supplying a gas to the first communication passage and exhausting the gas from the second communication passage when supplying melted resin into the mold to form the resin portion. According to the optical module producing method of the present invention, it is possible to use the communication path to supply a gas when molding the resin portion, so that fine particles of a volatile gas generated from the melted resin are prevented from adhering to the optical fiber and the optical system and forming a film when the volatile gas solidifies. For this reason, it is possible to prevent deterioration of the optical coupling between the optical fiber and the optical system, and the optical coupling part of the optical module is positively protected.
In the optical module producing method, the step (b) may supply pressurized dry air to the first communication passage.
Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.

Optical module and optical module producing method


A method and apparatus for associating an edge of a first object with a second object. An insert comprising a structure holding a fastener element may be positioned within a hollow portion at the edge of the first object. The structure may be configured to span an entire thickness of the first object at the edge of the first object. The structure may be adhesively bonded to the first object. The second object may be attached to the edge of the first object using the fastener element.

1. Field
The present disclosure relates generally to associating objects with each other. More particularly, the present disclosure relates to a method and apparatus for associating the edge of an object with another object using an insert that may be adhesively bonded to the object at the edge of the object.
2. Background
A composite object may be considered a sandwiched composite object when the composite object is comprised of a core layer of material that is sandwiched between a first layer of material and a second layer of material. The core layer of material may have a greater thickness than the first and second layers of material. In some cases, the core layer of material may be comprised of a honeycomb material, a foam material, or some other structure. A honeycomb material may be a material that has a honeycomb-like structure.
Oftentimes, all three of these layers may be exposed at the edge of a composite object. Attaching another object to the composite object at the edge of the composite object may require using one or more fastener components that have been installed at the edge of the composite object.
As one illustrative example, a bracket may be installed at the edge of the composite object. The bracket may surround a portion of the edge of the composite object and cover a portion of the outer surface of the first layer of material and a portion of the outer surface of the second layer of material. Consequently, in some cases, a bracket may change the shape of the outer surfaces of the composite object in an undesired manner. For example, without limitation, a bracket may change the evenness of these outer surfaces.
In another illustrative example, a fastener may be installed at the edge of the composite object using a cylindrical insert. For example, without limitation, a hole may be formed within the core layer of material at the edge of the composite object. The cylindrical insert may then be placed within this hole in the core layer of material. The fastener may then be installed within the cylindrical insert.
However, in some cases, the hole formed within the core layer of material may be rougher than desired. For example, without limitation, the edges of the hole may be uneven and rougher than desired. As a result, the cylindrical insert may not align with the hole in the core layer of material within selected tolerances. This type of misalignment may require additional processing of the hole, which may in turn, increase the overall time and/or effort needed to install the fastener. Further, in some cases, the cylindrical insert may increase the overall weight of the composite object more than desired.
Additionally, forming a hole within the core layer of material may have an undesirable effect on the structural integrity of the core layer of material. For example, without limitation, forming a hole within a honeycomb material may reduce the structural strength of the honeycomb material. Therefore, it would be desirable to have a method and apparatus that take into account at least some of the issues discussed above, as well as other possible issues.

Apparatus and method for associating the edge of a composite object with another object


The present invention provides a semiconductor device having a silicide thin film and method of forming the same. A semiconductor device comprises a gate insulation layer formed on an active region of a semiconductor substrate. A gate electrode is formed on the gate insulation layer. An impurity region is formed in the active region adjacent the gate electrode. A silicide thin film such as a cobalt silicide thin film is formed to a thickness of less than approximately 200 xc3x85 in the impurity region.

This application claims priority from Korean Patent Application No. 2001-14004, filed on Mar. 19, 2001, the contents of which are incorporated herein by reference in their entirety.
1. Field of the Invention
The present invention relates to a semiconductor device and method of forming the same, and more particularly to a semiconductor device having a silicide thin film and method of forming the same.
2. Description of the Related Art
Silicon generally has the properties of semiconductor, but acts as a conductor when impurities are implanted into it, as is the case when used in a semiconductor device. In addition, silicon and metal can be easily transformed into a metal silicide having high conductivity. Accordingly, in a highly-integrated semiconductor device in which resistance increases as the width of a conductive line such as a gate line and contact sizes are reduced, metal silicide is often used to form a portion of a contact interface or a signal line such as the gate line to enhance the conductivity and the performance of the device.
Also, as semiconductor devices are scaled down, the junction depths of source/drain regions are also reduced. To reduce the contact resistance of the source/drain regions, metal silicide can again be used. At this time, a layer of metal silicide is generally formed to a thickness of several hundred angstroms (xc3x85). However, for example, when the metal silicide layer having a thickness of 300 xc3x85 is formed on the source/drain regions having a thin junction depth of 1000 xc3x85, the metal silicide layer may be directly connected to the substrate beyond the source/drain regions. Consequently, various problems, such as a junction spiking phenomenon generating a leakage current, can occur. This junction spiking phenomenon is similar to the spiking problem in which the signal current leaks into the substrate when aluminum contact plugs are connected to the source/drain regions.
Cobalt or titanium (Ti) metals, having a low contact interface resistance such as are commonly used to form the metal silicide layer. With cobalt, however, the probability of encountering the junction spiking phenomenon is increased. The cobalt silicide layer is usually formed by coating a cobalt layer on the exposed surface of a substrate through sputtering. Sputtering is followed by a two-step heat treatment, in which a first step takes place at temperatures of 500 to 600xc2x0 C. and a second step takes place at more than 750xc2x0 C., or a one-step heat treatment that takes place at a high temperature of more than 750xc2x0 C. The heat treatment silicifies the cobalt layer. After the heat treatment, non-reacted portions of the cobalt layer are removed in a self-aligned manner by wet etching. Using this technique, it is difficult to control a speed of forming the cobalt silicide layer to form a thin layer. When the cobalt silicide layer is formed, the polysilicon layer and the cobalt layer are usually combined in a ratio of 360 xc3x85 to 100 xc3x85. It is further difficult to coat the cobalt layer uniformly at a thickness of less than 80 xc3x85 through sputtering and to re-form it repeatedly. The reliability of fabrication process is therefore deteriorated. Thus, forming the cobalt silicide layer of less than 300 xc3x85, as well as preventing the junction spiking phenomenon in the source/drain regions having the thin conjunction depth, is difficult.
When the signal current leaks into the substrate without being transmitted through channels, the consumption of the signal current is increased and the operation speed of transistors slows. Worst yet, the transistors may not operate properly. Particularly, in a low power SRAM device, it is necessary to prevent the generation of leakage current to obtain reliable operation of the device.
To prevent the spiking phenomenon that results from using the cobalt silicide layer, a titanium silicide layer (TiSi2) in the source/drain regions can be formed using titanium to reduce the spiking phenomenon. In this case, however, because titanium exhibits an amount of resistance that depends on the line width, the resistance is abruptly increased in most semiconductor devices having a line width of less than 0.2 xcexcm. Also, the resistance characteristics of the titanium may be degraded following heat treatment.
According to an aspect of the present invention, a semiconductor device comprises a gate insulation layer formed on an active region of a semiconductor substrate. A gate electrode is formed on the gate insulation layer. An impurity region such as a source/drain region is formed in the active region adjacent the gate electrode. A silicide thin film is formed to a thickness of less than approximately 200 xc3x85 in the impurity region.
According to another aspect of the present invention, there is provided a method of forming a semiconductor device comprising forming an isolation layer on a surface of a substrate to define an active region, forming at least one gate electrode by sequentially forming a gate insulation layer and a gate layer on the surface of the substrate in the active region and patterning them to expose source/drain regions, forming a metal layer such as a cobalt layer on the surface of the substrate in the exposed source/drain region, forming a low temperature type silicide thin film such as a cobalt silicide thin film by performing a heat treatment at a low temperature of 150 to 450xc2x0 C., preferably 300 to 400xc2x0 C. to the substrate on which the cobalt layer is formed, removing non-reacted portions of the cobalt layer from the substrate on which the low temperature type cobalt silicide thin film is formed, and forming a high temperature type metal silicide thin film such as a high temperature type cobalt silicide thin film by performing a heat treatment at a high temperature of more than 700xc2x0 C., preferably 850xc2x0 C. to the low temperature type silicide thin film.
In the invention, because the heat treatment after forming the cobalt layer is carried out at a low temperature, it is desirable that the low temperature type cobalt silicide thin film be formed in an in-situ method in a sputtering device after the sputtering. Also, instead of the cobalt layer, a layer of metal such as nickel, titanium and platinum can be used.

Semiconductor device having silicide thin film and method of forming the same


An approach to detecting objects in an image dataset may combine texture/color detection, shape/contour detection, and/or motion detection using sparse, generative, hierarchical models with lateral and top-down connections. A first independent representation of objects in an image dataset may be produced using a color/texture detection algorithm. A second independent representation of objects in the image dataset may be produced using a shape/contour detection algorithm. A third independent representation of objects in the image dataset may be produced using a motion detection algorithm. The first, second, and third independent representations may then be combined into a single coherent output using a combinatorial algorithm.

It is generally desirable for machine vision applications to be as accurate as possible while operating within reasonable computational constraints. Conventional systems generally rely on color/texture analyses that require targets objects to possess one or more highly distinctive, local features that can be used as distinguishing characteristics for a classification algorithm. Many objects, however, consist of materials that are widely prevalent across a wide variety of object categories. Much less effort has been made to characterize objects based on shape, or the particular way the component features are arranged relative to one another in two-dimensional (2D) image space. Accordingly, applying an approach that characterizes objects based on shape/contour may be beneficial. Moreover, less effort still has been made to characterize objects based on their motion properties, such as velocity. Applying an approach that characterizes objects based on perceived motion may also be beneficial. Furthermore, applying a single approach that characterizes objects using one or all of the three of the aforementioned methods may be beneficial.
It has been shown that hierarchical, or deep, models for solving computer vision problems are more generally advantageous than traditional flat architectures. Nearly all existing hierarchical approaches to computer vision are exclusively bottom-up or feed-forward in character. In such models, information flows in only one direction and each subsequent layer can be trained only after the previous layers have been completely learned. A fundamental disadvantage of this exclusively bottom-up or feed-forward approach is that the features that have been previously learned by a given layer in the hierarchy cannot be modified to take into account what is subsequently learned by succeeding layers. As a result, exclusively bottom-up/feed-forward networks contain a large amount of redundancy, with the same information being represented at each stage in the hierarchy. To reduce redundancy in the system, it may be preferable if instead, all of the layers in the hierarchy could be learned simultaneously in a competitive manner such that the information extracted by one layer was not redundant with any other layer, but rather encoded as unique information.
Another problem typically encountered in standard approaches to training hierarchical networks for solving computer vision tasks is that the dimensionality of underlying feature space will often increase from one layer to the next. This increase in dimensionality occurs because each subsequent layer in a hierarchical network receives convergent inputs from a spatial neighborhood of feature detectors located in the previous layer and because there are, in theory, a combinatorially large number of ways of combining spatially-distributed features. Thus the outputs of any given layer are typically of a higher dimensionality than its inputs. Spatial convergence is vital, however, for enabling hierarchical networks to learn feature detectors of increasing complexity and increasing viewpoint invariance at successively higher processing stages. Mathematically, hierarchical networks for solving computer vision tasks should, in general, need to contain progressively more neurons in each subsequent hierarchical layer in order to capture the increased dimensionality and complexity of their inputs. However, it is generally impractical to increase the size of each layer in a hierarchy ad infinitum, as the number of feature detectors in each subsequent layer would grow exponentially.
In a deep, hierarchical network, there is an incentive to introduce additional invariance at each subsequent layer. Traditionally, invariance is encoded into computer vision systems using a max or mean pooling operation, or some analogous procedure such as constructing a histogram of local activity levels. In this approach, layers are sub-divided into two sub-stages, a first stage including feature detectors that respond selectively to a particular pattern of inputs, and a second, typically smaller, stage of invariant detectors that pool over a small neighborhood of selective feature detectors in the first stage. Such pooling serves to reduce the dimensionality of the overall output of the layer and to introduce a small amount of additional invariance to local translations of the features or objects to be detected.
However, an approach based on max or mean pooling has been repeatedly shown to fail when scaling up from model datasets to real world problems. Additionally, max or mean pooling fails to account for any non-linear transformations that objects typically undergo, such as changes in viewpoint or shading. However, some mechanism for incrementally increasing invariance is desirable. A scalable, general scheme for incrementally increasing the invariance of the representations encoded at each layer in a visual processing hierarchy may be beneficial to the construction of computer vision systems for viewpoint invariant object detection.
Conventional computer vision solutions often perform color/texture analysis or shape/contour analysis. Traditionally, these solutions are viewed and compared independently. A composite approach that combines an improved shape/contour detection algorithm and an improved color/texture analysis algorithm may be more beneficial. Also, a single deep, sparse, hierarchical network that analyzes both color/texture and shape/contour features simultaneously may be desirable. Furthermore, conventional systems for solving computer vision problems generally require immense processing and memory resources. Accordingly, an approach that is amenable to hardware that requires less power to run while maintaining computational speed and accuracy may be beneficial.

Object detection approach using generative sparse, hierarchical networks with top-down and lateral connections for combining texture/color detection and shape/contour detection