An ultrasonic welding system, for welding together two workpieces wherein at least one of the workpieces includes a polymeric composite, comprising an energy applicator positioned along an action axis so that, in operation, ultrasonic vibrations transmitted from the energy applicator during a welding routine, are transmitted to the workpieces generally at and/or adjacent the axis. The system also includes a primary, course-control, actuator positioned along action axis so that a first load, output by the primary actuator, acts along the system action axis. The system further comprises a secondary, fine-control, actuator positioned along the system action axis so that a second load output, by the secondary actuator, acts along the axis. And the system comprises a controller for providing first command signals and second command signals to the primary actuator and second actuator to control them to effect loads on the workpieces, during the welding routine and along the axis.

In automotive manufacturing, polymeric composites are being used increasingly due to their favorable characteristics, such as being lightweight, highly-conformable or shapeable, strong, and durable. Some composites are further colorable and can be finished to have most any desired texture.
The increased use in automobiles includes, for instance, in instrument and door panels, lamps, air ducts, steering wheels, upholstery, truck beds or other vehicle storage compartments, upholstery, external parts, and even engine components. Regarding engine components, and other under-the-hood (or, UTH) applications, for instance, polymers are configured, and are being developed continuously, that can withstand a hot and/or chemically aggressive environment. Regarding external parts, such as fenders, polymers are being developed that have high heat, environmental, and chemical resistance over longer periods of time. And many other potential usages in automotive applications are being considered continuously.
With the increased use of polymers, polymer composites, and other low-mass materials, compression molding and post-mold joining techniques—e.g., ultrasonic welding—are also being used more commonly.
Some conventional ultrasonic welding techniques are open-loop controlled. Upon positioning of an ultrasonic energy applicator—e.g., ultrasonic tip, referred to as a sonotrode or horn—at a point of welding, the applicator is controlled, according to an open-loop program, to descend onto the part, transmit ultrasonic vibrations following contact, and continued to descend while transmitting the vibrations. Applicator kinematics, e.g., motion, is thus controlled in the same manner, according to the program, in each iteration of welding.
For some techniques, welding systems employ a sort of closed-loop feedback control to ensure that the horn vibration is maintained at a certain, constant resonance frequency—e.g., 20 kHz.
Due to variations in welding conditions, with parameters for each iteration being kept constant (i.e., constant horn vibration frequency, amplitude of vibration, and downward force on the workpiece), the same welding function does not yield the same results in each instance. Variations include, primarily, those related to the workpieces being welded together—e.g., workpiece material, workpiece size and shape, workpiece surface roughness, workpiece surface cleanliness, and workpiece positioning and securing (e.g., clamping). Environmental conditions, and condition, including cleanliness, of the energy applicator can also be factors.
Regarding component material, one or both workpieces may contain unintended contaminants. Or workpieces can include more or less basic material than desired, such as more or less carbon-fiber than specified. The contaminants, or surplus/deficiency in make-up materials, affect workpiece reaction to welding energy. The workpieces may melt slower, or more quickly, than usual, for instance.
Also regarding workpiece material, one or both workpieces might contain defects, such as unwanted porosity. Or there might be local differences in mechanical properties of workpiece material, such as due to changes in volume fraction or orientation of fibers (e.g., carbon fibers or glass fibers) in the case of fibrous composites—a fiber-reinforced polymer (FRP) composite.
Regarding workpiece size and shape, it has been found, for example, that a relatively-slight change in volume (e.g., 2%), or difference in a local thickness or contouring, can have a relatively large affect on material melting properties.
Regarding workpiece positioning and clamping, one or both workpieces sometimes becomes malpositioned originally or due to improper clamping. Even a slight malpositioning can affect welding. Less than optimal contact between the weld energy applicator (e.g., horn) and a proximate workpiece, for instance, can lower welding effectiveness significantly in a conventional open-loop system.
Surface-related characteristics—e.g., cleanliness, roughness (rougher or smoother than specified (e.g., in a specification)), and coatings (e.g., too little or too much of a coating)—also affect the efficiency with which the ultrasonic vibrations are transferred to and through the workpieces.
Because conventional, open-loop, techniques do not accommodate variations affecting the weld process—such as contaminants in the workpiece or an unclean workpiece surface, overwelding and underwelding is common in use of those techniques.
Overwelded parts may be undesirable cosmetically, for example. Over welded joints may be weaker, e.g., due to excessive heating/melting of the material, resulting in weaker mechanical properties in and around the joint.
And overwelding may require more energy and time than desired. In a contemplated scenario, for instance, in which a welding horn is lowered until the horn lowers to a pre-set depth of the workpiece, more energy and time will be expended if the workpieces are melting slower than expected.
Underwelded parts, of course, produce weaker joints due to an undesirably low amount of bonding between the workpieces.
Underwelded and overwelded parts may need to be repaired, recycled, or scrapped.
The present technology addresses these and other shortcomings of prior welding techniques.

Systems and methods for adaptive process control using a target kinematics profile in welding together multiple polymeric workpieces


A safety harness system to facilitate attachment and storage of a safety harness. The safety harness is secured to a garment to allow the safety harness to be removed and stored with the garment, thereby preventing entanglement and loss of the safety harness during removal and storage. By securing the safety harness to the garment, the safety harness is less likely to become tangled, lost or damaged during storage.

1. Field of the Invention
The present invention relates in general to an improved safety harness and, more particularly, to a safety harness releasably secured to a garment.
2. Description of the Prior Art
Safety harnesses are well known in the art. Such harnesses are used by hunters, construction workers, roofers, power line workers and others working at dangerous heights from the ground. Such safety harnesses typically secure around a user's waist and shoulders, and is coupled by a safety line to a tree, a pole, or similar structure to prevent the user from falling in the event the user loses footing. While such safety harnesses have saved hundreds of lives, they do include a drawback.
Prior art safety harnesses typically involve several straps which often become entangled with one another between removal, storage and reattachment to a user. This entanglement not only makes it difficult to secure the safety harness to the user, but also may decrease the effectiveness of the safety harness in the event that the safety harness is secured to the user with tangled lines. Additionally, given the difficulty associated with untangling the lines, and the possibility of losing the safety harness during storage, the user may decide not to use the safety harness, thereby putting the user at risk of death or serious injury. It would, therefore, be desirable to provide a safety harness which was easy to secure and remove from a user, which was easy to store, and which reduced the likelihood of becoming tangled. The difficulties encountered in the prior art discussed hereinabove are substantially eliminated by the present invention.


An apparatus for inline monitoring of transmit signals is disclosed. The apparatus includes a processor, and one or more fiber optic lines for supplying a transmit signal to/from a remote transmission station. The processor is configured to receive input for selecting one or more fiber optic lines for examination, determine at least one property of the transmit signal to be monitored, and retrieve information corresponding to the at least one property for a predetermined period of time. The processor is further configured to output a visual representation of the retrieved information, perform an analysis of the retrieved information and the visual representation, and facilitate identification of at least one status associated with the transmit signal based, at least in part, on the analysis.

Modern communication systems are complex and require the use of a great number of hardware components for proper operation. Hardware components, however, can be subject to malfunction and failure. Such failure can result in significant system downtime and/or customer dissatisfaction. Depending on the particular hardware, for example, customers may be unable to access some or all features of the system including data, voice, etc. Furthermore, customers may contact service centers to voice dissatisfaction, possibly resulting in a desire to change service providers. It is also necessary to staff sufficient representatives to address customer concerns, thereby resulting in additional costs for the service provider.
Identifying the cause of hardware malfunction can be difficult due to the overall complexity of the system. For example, an individual substation within a communication network can have a great number of hardware components that are susceptible to hardware and/or software failure. It is typically necessary to test hardware components individually in order to verify proper operation, thus requiring a significant amount of time. Furthermore, signals are received from and transmitted to different substations, and errors can be propagated from one substation to another, thereby making it increasingly difficult to identify the error source. Based on the foregoing, it would be desirable to provide an approach for improving the manner in which errors (e.g., hardware, software, configuration, etc.) are isolated in a communication system.

Apparatus and method for inline monitoring of transmission signals


A cartridge chip for use with a first type of imaging cartridge and a second type of imaging cartridge comprises a controller and a resistive element connected between the controller and a reference potential, the cartridge chip adapted for operation in a first mode of operation compatible with the first type of imaging cartridge when the controller detects the reference potential through the resistive element, the cartridge chip adapted for operation in a second mode of operation compatible with the second type of imaging cartridge when the controller cannot detect the reference potential through the resistive element.

The present invention generally relates to manufacturing and repairing replaceable imaging components, and more particularly to techniques for providing a cartridge chip comprising a memory element adapted for selectably operating in different types of imaging cartridges.
In the imaging industry, there is a growing market for the remanufacture and refurbishing of various types of replaceable imaging components such as toner cartridges, drum cartridges, ink cartridges, and the like. Imaging cartridges, such as toner cartridges, once spent, are unusable for their originally intended purpose. Without a refurbishing process, they would simply be discarded, even though the cartridge itself may still have potential life. As a result, techniques have been developed specifically to address this issue. These processes may entail, for example, the disassembly of the various structures of the cartridge, replacing toner or ink, cleaning, adjusting or replacing any worn components and reassembling the cartridge.
Some imaging cartridges may include a cartridge chip having a memory device which is used to store data related to the cartridge or the imaging device. An imaging device may include laser printers, copiers, inkjet printers, facsimile machines and the like, for example. The imaging device, such as the printer, reads this data stored in the memory device to determine certain printing parameters and communicate information to the user. For example, the memory may store the model number of the cartridge so that the printer may recognize the cartridge as one which is compatible with that particular printer. Additionally, by way of example, the cartridge memory may store the number of pages that can be expected to be printed from the imaging cartridge during a life cycle of the cartridge and other useful data. The imaging device may also write certain data to the memory device, such as the amount of toner remaining in the cartridge. Other data stored in the cartridge may relate to the usage history of the imaging cartridge.
For a given imaging device such as a printer, the appropriate cartridges may be available in a variety of styles. Lexmark, for example, may sell a "Use and Return" cartridge and a "Non Use and Return" cartridge for a given printer model. Both of these types of cartridges interface with the printer in different ways and may include differing physical characteristics, such as different encoder wheels. Different functionality may need to be provided the cartridge chip for each of these types of cartridges. Previously, a single cartridge chip having a switch was utilized for both types of cartridges. Based on the setting of the switch, the cartridge chip would be compatible with one of the cartridge types. However, these switches increase both the cost and size of the cartridge chip. Thus, it would be advantageous to provide systems and methods for selecting a mode of operation for a cartridge chip which is user friendly, cost effective and minimizes the space consumed on the cartridge chip.

Systems and methods for imaging components


An image processing apparatus includes: an image reading unit that reads image information; a generating unit that generates new additional information to be added to the image information read by the image reading unit; an extracting unit that extracts, in a case where the image information read by the image reading unit includes existing additional information, the existing additional information; and an additional information processing unit that embeds the existing additional information and the new additional information in the image information.

1. Technical Field
The present invention relates to an image processing apparatus, an image processing method, a computer readable medium, and a computer data signal.
2. Related Art
In recent years, in the case of performing output processing on an original, for example, outputting the original by a printer, or copying the original by a copier, there has been a fear of the possibility of leakage of secret information.

Image processing apparatus, image processing method, and computer readable medium, for generating and extracting image information


An improved step ladder of a type having at least one step and a corresponding number of step pads. The improvement includes each step pad being replaceably and interchangeably attached to an associated step, each step having a plurality of throughbores extending vertically therethrough, each step pad having a plurality of tits depending. therefrom that replaceably and interchangeably engage in the plurality of throughbores in the associated step, respectively, and each tit having a wide base coincident with the associated step pad, a pointed tip that facilitates entering into an associated throughbore, and a pinched waist which is releasably captured in the associated throughbore when the pointed tip passes into the associated throughbore, a distance requiring the tit to compress so as to allow the pinched waist to receive the step and then expand to releasably capture the step in the pinched waist, and as a result thereof, releasably lock the step pad onto the associated step.

1. Field of the Invention
The present invention relates to a step ladder. More particularly, the present invention relates to an improved step ladder.
2. Description of the Prior Art
Numerous innovations for step related devices have been provided in the prior art that will be described. Even though these innovations may be suitable for the specific individual purposes to which they address, however, they differ from the present invention.
FOR EXAMPLE, U.S. Pat. No. 4,029,280 to Golz teaches a pair of screen or storm sash supporting attachments in the form of wooden blocks that are releasably secured on the step of a step ladder by U-shaped brackets. The forward ends of the attachments being provided with a plurality of spaced sash-holding lugs with anti-slip treads therebetween for holding the lower end of a screen or storm window sash from outward sliding movement.
ANOTHER EXAMPLE, U.S. Pat. No. 5,103,608 to Andreo teaches an improved stair nosing device especially useful in temporarily darkened stairways which includes a plate member with an upper surface, at least a portion of which is covered by luminescent material. The stair nosing device includes non-slip material attached to the upper surface to provide increased frictional contact with foot traffic relative to the plate member. The non-slip material is attached as spaced apart strips with an upper surface of the non-slip material being higher relative to the plate member. In this way the luminescent material is protected from damage by foot traffic.
STILL ANOTHER EXAMPLE, U.S. Pat. No. 5,111,908 to Reiter et al. teaches a pipe step for providing a flat supporting surface on the top side of a horizontal pipe. The step includes a pair of channel members each having arcs cut in the flange portions thereof to meet with the pipe. U-bolts are provided for clamping the channel members to the pipe. A flat-supporting surface formed from square mesh grating is bolted to, and extends between, the upper web portions of the channel members and provides a non-slip flat supporting surface.
YET ANOTHER EXAMPLE, U.S. Pat. No. 5,587,218 to Betz teaches an improved surface covering that includes a base having a plurality of receiving grooves on one side and a plurality of working grooves on the other side. Each receiving groove includes gripping projections and is constructed to receive, and grip, a filler material. To assemble the surface material, the base material is flexed so that the size of the receiving grooves is enlarged thereby making insertion of the filler material easy. The base material is then returned to its original planar configuration, so that the size of the receiving grooves is retracted thereby causing the gripping projection to grip and hold the filler material.
STILL YET ANOTHER EXAMPLE, U.S. Pat. No. 6,088,976 to Roy teaches a removable non-skid pad that covers a portion of a corresponding step of an exterior stair or staircase so as to allow people to use it more safely. The pad includes a main section to be disposed on the upper horizontal portion of the step, a preformed substantially hooked-shaped form section having one end integrally connected to the front end of the main section so as to fit around the front edge and a part of the bottom portion of the step near the front edge, and a rear section having one end integrally connected to the rear end of the main section. A binding assembly is provided to removably attach the front and rear sections under the step. The pad may be easily installed and removed. Any snow or ice accumulations may be easily dislodged by removing the pad and skating it.
It is apparent that numerous innovations for step related devices have been provided in the prior art that are adapted to be used. Furthermore, even though these innovations may be suitable for the specific. individual purposes to which they address, however, they would not be suitable for the purposes of the present invention as heretofore described.
ACCORDINGLY, AN OBJECT of the present invention is to provide an improved step ladder that avoids the disadvantages of the prior art.
ANOTHER OBJECT of the present invention is to provide an improved step ladder that is simple and inexpensive to manufacture.
STILL ANOTHER OBJECT of the present invention is to provide an improved step ladder that is simple to use.
BRIEFLY STATED, YET ANOTHER OBJECT of the present invention is to provide an improved step ladder of a type having at least one step and a corresponding number of step pads. The improvement includes each step pad being replaceably and interchangeably attached to an associated step, each step having a plurality of throughbores extending vertically therethrough, each step pad having a plurality of tits depending therefrom that replaceably and interchangeably engage in the plurality of throughbores in the associated step, respectively, and each tit having a wide base coincident with the associated step pad, a pointed tip that facilitates entering into an associated throughbore, and a pinched waist which is releasably captured in the associated throughbore when the pointed tip passes into the associated throughbore, a distance requiring the tit to compress so as to allow the pinched waist to receive the step and then expand to releasably capture the step in the pinched waist, and as a result thereof, releasably lock the step pad on the associated step.
The novel features which are considered characteristic of the present invention are set forth in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of the specific embodiments when read and understood in connection with the accompanying drawing.


A door illumination apparatus directs light emitted by a string of diodes towards a face of an exterior door to enhance visual identification of a door lock. The apparatus positions on a periphery of a door jamb, such as in a recess in a jamb stop. The illumination apparatus actuates on demand from a user, lighting the door face through three-way switches that are operable from a position in proximity to the door, at least one of which three-way switches being a compatible electronic three-way switch which is operable remotely from a device configured to be carrier by a user.

1. Field of the Invention
The present invention relates to an illumination apparatus for the face of an exterior door. More particularly, the illuminating apparatus projects light onto the face of the door for enhanced visual identification of a door lock.
2. Brief Description of the Prior Art
The following background information may present examples of specific aspects of the prior art (e.g., without limitation, approaches, facts or common wisdom) that, while expected to be helpful to further educate the reader is not to be construed as limiting the present invention, or any embodiments thereof, to anything stated or implied therein.
In the dark, such as during the night or during a storm, the exterior of a door may not be clearly visible and a user may find it problematic to locate the door lock. While many homes have outside lights, they must be turned on when leaving the premises and must remain on until a person returns and turns the light off. This wastes energy if the user leaves during the day. In addition, exterior lights burning during the day may draw attention that the premises are unoccupied, thereby causing a security issue.
Light-emitting diodes (LEDs) are used as indicator lights in many devices and increasingly used for other lighting. LEDs have long service life, extreme vibration resistance and permit considerably shallower mountings compared to most bulb-type assemblies.
Even though porch lights address some of the needs of the market, there is need for an illumination apparatus that projects light on a door lock when needed under control of a user from the outside of the door.


Usage information of a user for a plurality of computing devices is identified. A usage pattern for each computing device of the plurality of computing devices of the user is developed based on the identified usage information of the user. An indication of the user accessing an application on a first computing device of the plurality of computing devices is received. The application requires one or more credentials for an authentication process associated with the application. A determination is made whether the user accessing the application using the first computing device is following the developed usage pattern of the user. Responsive to determining that the user accessing the application using the first computing device is not following developed usage pattern of the user, the authentication process associated with the application is interrupted.

The present invention relates generally to the field of multi-factor authorization, and more particularly to providing multi-factor authorization with more than one computing device.
Today, accessing your bank via a website is but a few touches away when using a smartphone. Often, all that is required is a username and a password. Once a user submits those credentials, the user is "in" and has access to their bank just as if they were standing in front of a teller. Some banks require multi-factor authorization (MFA). Stated simply, MFA is an authentication method in which two or more pieces of "evidence" (or factors) are presented by a user to an authentication mechanism before the user is granted access. The factors include (i) knowledge, i.e., something the user, and only the user, knows; (ii) possession, e.g., something the user, and only the user, possesses; and (iii) inherence, i.e., something the user, and only the user, is.

Multi-factor authentication via multiple devices

International Business Machines Corporation


A method for changing an effective capacitance of an amplifier circuit having a match transistor and a coupled cascode transistor includes changing an on-state of at least one of a plurality of sub-transistors of the match transistor. The method further includes changing a transconductance of the match transistor as a function of the change of the on-state. The method further includes changing an equivalent resistance, as measured between a source and a drain of the cascode transistor, as a function of the change of the transconductance of the match transistor.

Wireless technologies are of great importance in today's marketplace, and will continue to be so in the future. In wireless technologies, one figure of merit is a degree of impedance "match" between an antenna and amplifier of a wireless device.
A proper input matching has a great influence on both a gain and a noise factor of an amplifier. Components of wireless devices, such as surface acoustic wave ("SAW") filters, work properly only when a correct impedance is presented at its terminals. Typically, the amplifier should be able to maintain its performance even for a voltage standing wave ratio ("VSWR") of 3:1.
However, the input impedance, as seen by the wireless device, can change over time. Therefore, an impedance mismatch occurs. This impedance mismatch can occur due to an aging antenna, a change in an orientation of the antenna, or other things.
However, there are drawbacks with prior art approaches of compensating for impedance mismatches. For instance, one or a series of physical capacitors can be placed between a gate of the amplifier and ground, or various couplings of inductors between the gate of the transistor and an input of a device under test can be placed between a gate of the amplifier and ground to achieve impedance matching. However, significant complexity and noise of the switches can be added in this aspect, and significant integrated circuit area can be consumed.
Accordingly, what is needed in the art is a system and a method to match input impedances that addresses the drawbacks of the prior art.

Reconfigurable circuit to compensate for a low noise amplification input matching variation and a method for its configuration


A toilet paper roll holder with wet wipe is described. In one embodiment, a system includes an elongated container body, a first endcap, a second endcap, at least one connector, and a bias member. The elongated container body has a central first axis, an internal storage space, a first end, and a second end. The elongated container body fits within a toilet paper roll. The first endcap is coupled to the first end of the elongated container body. The second endcap is coupled to the second end of the elongated container body. The second endcap includes an access lid to provide access to the internal storage space. The at least one connector is to secure the system relative to a mounting location on a second axis. The bias member is on a third axis. The bias member is coupled between the at least one connector and the elongated container body.

Despite multiple attempts to improve the adoption of wet wipes by consumers, the disposable wipe industry has been slow to gain market share on the toilet paper field. One option for making disposable wipes accessible to a consumer is a package or container that typically sits on a counter top. However, this option does not fit within the typical bathroom experience of a consumer who is accustomed to sitting at the toilet and having ready access to toilet paper at a mounting location such as toilet paper brackets mounted on the wall or on a stand-alone unit placed within reaching distance from a seated position on the toilet.
Some proposed solutions have attempted to overcome this challenge by wholly replacing the toilet paper roll with a wet-wipe container hung from the toilet roll brackets. Though this places the wipes in a convenient location, it does so by eliminating traditional access to toilet paper. Market research suggests that the majority of wet-wipe consumers also use toilet paper while seated at the toilet.
Further systems have attempted to provide access to both wet wipes and toilet paper at the toilet roll bracket by limiting the size of the toilet paper roll or by providing a relatively small amount of wet wipes which are stored within the wet-wipe dispenser. The challenge with these options is that they create an experience that is much less convenient because the consumer is required to refill the toilet paper roll or the wet wipes on a much more frequent interval.
For example, some approaches use the core of the toilet paper roll to store wet wipes. U.S. Pat. No. RE45,809E attempts to provide a way to dispense wet wipes in a bathroom by utilizing the space in the core of the toilet paper roll. This design utilizes the existing installations of toilet roll brackets without requiring modification or new equipment. However, the design of RE45,809E does not resolve the concern of extremely limited storage space for wet wipes available inside the core of the toilet paper roll. The design further limits the wet wipe storage space by placing other mechanical features such as the spring (and other pieces required for the functionality of the device) inside the core of the toilet paper. Additionally, because of the opening on the end of the device for dispensing of wet wipes, it does not provide a complete barrier to prevent the loss of moisture from the wet wipes stored inside the device.

Toilet paper holder with a wet-wipe container body


In a traditional multi-port memory, the writing of a memory cell is performed only by the single port which is enabled for writing. Row contention occurs when other ports access the same memory cell, such as when ports share the same row address, and when the other ports are reading previously-stored data of opposite polarity. A parallel write capability is disclosed which eliminates such row contention by using the other ports of a multi-port memory to assist in writing the memory cell. By forcing the other ports into a write of the same data there can be no contention. Whenever a read port accesses the same row as a write port, the read port's bitline corresponding to the selected column for the write port is also forced into a write of the write port's data, along with the write port's bitline corresponding to the selected column of the write port. The read port's data is unaffected regardless of whether the selected column for the read port differs from the selected column for the write port. Row contention is also eliminated when multiple ports simultaneously write.

1. Field of the Invention
The present invention relates to read/write memory arrays, and more particularly to those arrays having multiple read/write ports thereto.
2. Description of the Related Art
In a traditional single-port memory array, a single address is presented to the array, and a memory cell identified by that address is either written with data presented to the port, or is read from the array and thus drives data outputs corresponding to the port. The single address may include a large number of individual address bits to fully specify each of the individual memory cells in the array. For example, a 20-bit address is required for a 1 megabit memory array which has a single data input/output bit (a 1MB.times.1 memory array). The number of memory cells selected by a particular address may be one, as in the above example, or may be more than one. Memory arrays which simultaneously address, for example, eight bits of data are frequently desirable to increase the amount of data which is either read or written during each memory operation. In such a "byte-wide" memory array eight memory cells are simultaneously selected for each particular address presented to the port. In a write cycle (i.e., write operation) each of the selected memory cells is written with a respective one of eight bits of data presented to the port. Conversely, in a read cycle (i.e., read operation) each of eight data outputs for the port is driven with data read from a respective one of the eight selected memory cells. Memory arrays as discussed above may be configured as part of a commodity memory product (such as the well known products of the type typically incorporated into a memory SIMM for a personal computer), or may be configured as part of a larger system, such as a processor, cache subsystem, DMA channel, network interface, or a wide variety of other systems or subsystems.
While the great bulk of memory used today is configured with a single port as described above, memory arrays which are addressed independently by more than one port, known as multi-port memory arrays, are increasingly used by system architects to achieve a variety of performance and/or functionality goals. For example, dual-port memory arrays are frequently used as buffers between two subsystems which are asynchronous to each other. FIFO's (first-in-first-out buffers) are specialized sequentially-accessed dual-port memories. Moreover, memories specially adapted for frame memory within a video system (e.g., VRAMs) allow simultaneous and independent access by both a processor as well as a video subsystem so that each is not interrupted when the other accesses the memory array. A register file of a processor may be configured with two read ports and one write port, so that two operands for a pending operation may be simultaneously retrieved while a result from a completed operation is written. Other sophisticated applications continue to require an even greater number of ports into a memory array. Achieving additional ports in a memory array has traditionally resulted in a significant penalty in chip area or die size (the layout size of the memory array) as well as a penalty in performance of the memory array. To achieve large numbers of ports, high-density high-performance memory array structures cannot be used, and structures resembling a logic gate implementation of the memory array are frequently used instead.
A traditional "4T-2R" single-port static memory cell (also sometimes known as a "4T" cell) is depicted in FIG. 1. Two cross-coupled N-channel transistors (transistors 116 and 118) form the basic storage element of the memory cell 101. These transistors 116 and 118 couple internal nodes 108 and 110, respectively, to a common terminal 100 which is typically connected to receive a reference voltage such as electrical ground. For descriptive convenience, such a common terminal 100 is commonly referred to as a ground terminal, and will hereinafter be referred to as ground terminal 100. Resistors 120 and 122 couple internal nodes 108 and 110, respectively, to a power supply terminal 105 which is typically connected to receive a positive power supply voltage which may typically be in the several volt range, with 3.3 volts and 5.0 volts being common examples. Such a positive power supply voltage is frequently referred to as a V.sub.DD voltage, and for descriptive convenience the power supply terminal 105 will hereinafter be referred to as V.sub.DD terminal 105. The resistors 120 and 122 are typically implemented using a high resistivity polysilicon film which is largely stacked above the transistors of the memory cell which are implemented in lower semiconductor layers. Consequently, use of such resistors 120 and 122 results frequently in a smaller memory cell layout than an alternative "6T" memory cell design which uses P-channel transistors for the load elements (See FIG. 3 and related discussion hereinafter). The two resistors 120 and 122 are designed to be extremely high magnitude resistors in order to minimize the static current flow (i.e., the "DC" current) through the memory cell 101.
The internal nodes 108 and 110 of the memory cell 101 are coupled through a pair of N-channel access transistors 112 and 114 to a pair of respective bit lines 104 and 106. These bitlines 104 and 106 are used for both reading and writing the memory cell 101 when the wordline 102 is enabled and provide for a single data port into the memory cell 101. One of the bitlines, such as bitline 104, is commonly referred to as the true bitline 104 and the other bitline, such as bitline 106, is commonly referred to as the complement bitline 106. Since the cell is symmetrical, such a designation is arbitrary at the cell level and in practice may result from product data polarity designations or designer preference. For convenience, the pair of bitlines 104 and 106 may hereinafter also be referred to as the true bitline 104 and the complement bitline 106. The operation of a such a memory cell 101 depicted in FIG. 1 is well known by those skilled in the art.
A traditional "4T-2R" dual-port static memory cell 151 is depicted in FIG. 2. As before, two cross-coupled N-channel transistors (transistors 166 and 168) form the basic storage element of the memory cell 151. These transistors 166 and 168 couple internal nodes 158 and 160, respectively, to the ground terminal 100. Resistors 170 and 172 couple internal nodes 158 and 160, respectively, to the V.sub.DD terminal 105. The resistors 170 and 172 are likewise typically implemented using a high resistivity polysilicon film and are designed to be extremely high magnitude resistors.
The internal nodes 158 and 160 of the memory cell 151 are coupled through a first pair of N-channel access transistors 162 and 164 to a first pair of bit lines 154 and 156, and are also coupled through a second pair of N-channel access transistors 163 and 165 to a second pair of bit lines 155 and 157. The first pair of bitlines 154 and 156 is used for both reading and writing the memory cell 151 when a first wordline 152 is enabled, and together provide for a first data port into the memory cell 151. The second pair of bitlines 155 and 157 is similarly used for both reading and writing the same memory cell 151 when a second wordline 153 is enabled, and together provide for a second data port into the same memory cell 151 . For convenience, the first pair of bitlines 154 and 156 may hereinafter also be individually referred to as the port 1 true bitline 154 and the port 1 complement bitline 156, respectively. Furthermore, the second pair of bitlines 155 and 157 may hereinafter also be individually referred to as the port 2 true bitline 155 and the port 2 complement bitline 157, respectively.
An alternative arrangement of a dual-port static memory cell is depicted in FIG. 3. Memory cell 151a has load elements fashioned from a pair of cross-coupled P-channel transistors rather than from high value polysilicon resistors. Cross-coupled P-channel transistors 174 and 176 couple internal nodes 158a and 160a, respectively, to the V.sub.DD terminal 105. As mentioned before, such a cell traditionally results in a larger cell layout not only due to the inclusion of two additional transistors, but also due to the requirement for providing N-well to P-well isolation within each memory cell of a memory array. Potential advantages of P-channel loads for a multi-port memory cell are discussed further herebelow.
A four-port memory cell having resistor loads is depicted in FIG. 4 as memory cell 201. It should be noted that such a four-port memory cell 201 has not been successfully implemented, although it is seemingly a straightforward extension of the two-port memory cell 151 shown in FIG. 2, for the reasons to be described below (and potentially for other reasons, as well). As before, two cross-coupled N-channel transistors 216 and 218 form the basic storage element of the memory cell 201 and couple internal nodes 208 and 210, respectively, to the ground terminal 100. Resistors 220 and 222 couple the internal nodes 208 and 210, respectively, to the V.sub.DD terminal 105. The resistors 220 and 222 are likewise typically implemented using a high resistivity polysilicon film and are designed to be extremely high magnitude resistors.
The internal nodes 208 and 210 of the memory cell 201 are coupled through a first pair of N-channel access transistors 212.1 and 214.1 to a first pair of bit lines 204.1 and 206.1, thus forming a first port. A second pair of N-channel access transistors 212.2 and 214.2 couples the internal nodes 208 and 210, respectively, to a second pair of bit lines 204.2 and 206.2, thus forming a second port. A third pair of N-channel access transistors 212.3 and 214.3 couples the internal nodes 208 and 210, respectively, to a third pair of bit lines 204.3 and 206.3, thus forming a third port. Lastly, a fourth pair of N-channel access transistors 212.4 and 214.4 couples the internal nodes 208 and 210, respectively, to a fourth pair of bit lines 204.4 and 206.4, thus forming a fourth port. A first wordline 202.1 is connected to the gate terminal of access transistors 212.1 and 214.1 to control the first port. Similarly, additional wordlines 202.2, 202.3, and 202.4 control the second, third, and fourth ports, respectively. Referring to the first port, the bitlines 204.1 and 206.1 may be defined to be the true and complement bitlines, respectively, for port 1, and for convenience may also be referred to as bitlines BL.sub.-- P1 and XBL.sub.-- P1 (the initial character "X" implying the complement polarity). Similarly, the bitlines 204.2 and 206.2 would follow as true and complement bitlines, respectively, for port 2, and may be referred to as bitlines BL.sub.-- P2 and XBL.sub.-- P2; bitlines 204.3 and 206.3 would follow as true and complement bitlines, respectively, for port 3, and may be referred to as bitlines BL.sub.-- P3 and XBL.sub.-- P3; and bitlines 204.4 and 206.4 would follow as true and complement bitlines, respectively, for port 4, and may be referred to as bitlines BL.sub.-- P4 and XBL.sub.-- P4.
A well designed memory cell (having an adequately high ratio of the cross-coupled transistors (e.g., transistor 218) to the access transistors (e.g., transistor 214.4)) is usually able to be read by virtually any number of read ports. However, a significant problem materializes as the number of ports which can write to the cell increases. This can be illustrated by first assuming that a logical "0" is stored within the memory cell 201. This results in a low voltage, V.sub.LO, on internal node 208, and a high voltage, V.sub.HI, on internal node 210, as indicated in FIG. 4. Next assume that ports 1, 2, and 3 are enabled to read the memory cell, while port 4 is enabled to write a logical "1" (being opposite data to that previously stored) into the memory cell 201. To write a logical "1" through port 4, bitline BL.sub.-- P4 is driven high and bitline XBL.sub.-- P4 is driven low. Since all 4 ports are active, all four wordlines 202.1, 202.2, 202.3, and 202.4 are active and thus driven high. A write current, I.sub.WR, flows from internal node 210 through access transistor 214.4 to the bitline XBL.sub.-- P4 to cause the memory cell 201 to change states. Such a state change occurs when the voltage on internal node 210 decreases sufficiently to turn transistor 216 substantially off, thus allowing access transistor 212.4 to charge internal node 208 to a higher voltage. Such a high voltage on internal node 208 turns on transistor 218 and causes the voltage of internal node 210 to remain well below the threshold voltage of transistor 216, even after the write operation has concluded and the access transistors 212.4 and 214.4 have turned off. The voltage of internal node 210 must be driven to a rather low voltage for transistor 216 to begin to turn off, which is necessary before the cell data can switch states.
Achieving a sufficiently low voltage on internal node 210 is made more difficult by the simultaneous reading of the same memory cell 201 through port 1, port 2, and port 3, however. As internal node 210 falls in voltage, a read current, I.sub.RD, flows from bitline XBL.sub.-- P1 through access transistor 214.1 to internal node 210. Likewise, a read current, I.sub.RD, also flows from bitline XBL.sub.-- P2 through access transistor 214.2, and from bitline XBL.sub.-- P3 through access transistor 214.3, all as shown in FIG. 4. The source of this read current I.sub.RD is two-fold. A first component originates from each of the bitline load devices 230 connected to each of the bitlines. But even if such load devices 230 are made smaller, a second component arises from the capacitance of the bitlines themselves. In the above example, each of bitlines XBL.sub.-- P1, XBL.sub.-- P2, and XBL.sub.-- P3 would have to be significantly discharged by the read current I.sub.RD before the memory cell 201 is written to a logical "1," and all of the current to discharge the three bitlines which are engaged in reading must be conducted through access transistor 214.4. This results in a huge variation in the write time of a cell depending upon the number of other ports which are reading the same cell. Moreover, the conditions described in the example above are true not only for other read ports accessing the same cell, but are also true for any other cell sharing the same wordlines: that is, whenever the row address of a port which is reading is the same as the row address of a port that is writing, even if the column addresses are different. Such a problem may be called row contention of a multi-port array.
As additional ports are added to a memory cell, it is possible that a single write port is unable to sufficiently discharge a cell to ever write the data, no matter how much time is allowed for the discharging of bitlines associated with ports which are reading. This occurs when the effective voltage divider formed between access transistors which are reading (in the above example, e.g., access transistors 214.1, 214.2, and 214.3 acting in parallel) and the access transistor which is writing (e.g., access transistor 214.4) is insufficient to drive the internal node of the memory cell (e.g., internal node 210) below the trip point of the memory cell.
This row contention phenomenon may be reduced by utilizing a memory cell having P-channel load devices, analogous to that shown in FIG. 3, because the trip point of such a memory cell can be made to be higher than a memory cell utilizing high resistance polysilicon load resistors. But the lengthening of write timing due to the necessary discharging of bitlines associated with ports which are reading still creates a tremendously undesirable characteristic for a user of the multi-port memory array to deal with.
What is needed is a memory structure which can support additional numbers of ports without either a static write incapability, nor a dynamic write timing penalty when row addresses on multiple ports happen to match. What is needed, in other words, is a memory structure which eliminates row contention.

Parallel write logic for multi-port memory arrays


A high rate, upflow filtration system is described in which a compressible, fibrous lump filtration media is compressed to adjust the porosity and collector size of the media in the bed and to provide a porosity gradient within the bed proceeding from more porous to less porous in a direction opposite to the flow of fluid so that filtration proceeds in a direction from a more porous to a less porous filter bed. Larger particles are removed by the more porous media and successively smaller particles are removed as the filter bed becomes less porous. The system is capable of reducing the turbidity of influent municipal wastewater from about 8 NTU to about 2 NTU at a wastewater flow rate of from about 820 to 1230 L/m2·min (20 to 30 gal/ft2·min), at a bed compression ration of from about 15 to 40 percent, and at a backwash rate of from about 1 to 6 percent based on the total wastewater passing through the filter.

Disposal and reuse of wastewater from raw municipal sewage is problematic. Stringent wastewater treatment requirements have been promulgated to protect human health, particularly in those areas having limited water supply or dense populations. For example, Title 22 of the California Administrative Code establishes stringent water reuse criteria where human contact is likely to occur with treated wastewater.
Typically, wastewater is disinfected by chlorination or ultraviolet irradiation where the treated wastewater is discharged to inland surface waters. Disinfection of this type typically achieves complete destruction of pathogenic bacteria and substantial deactivation of viruses, but does not provide complete virus destruction. Viruses have been detected in secondary effluents.
Title 22 of the California Administrative Code is directed to tertiary treatment requirements. Viral monitoring is not specified in Title 22 because viruses typically occur in low concentrations in treated wastewater. Viral monitoring is expensive. Viral assays require special expertise. Laboratory procedures usually are off line and time consuming. Analytical costs are high. Therefore, instead of imposing measurements of viral concentrations, Title 22 sets forth a tertiary treatment system that consists of chemical coagulation, sedimentation, filtration, and disinfection where the public may exposed to the treated wastewater, as in a recreational impoundment.
Under the provisions of Title 22, turbidity of the treated effluent normally cannot exceed an average operating value of 2 NTU after final filtration, and cannot exceed 5 turbidity units more than 5 percent of the time during any 24 hour period. Chlorination after this level of treatment typically insures effective virus destruction sufficient for the protection of public health. Direct filtration with chemical addition is allowed as an alternative to the complete treatment systems specified in Title 22 where it has been demonstrated that the results of the two treatment systems are comparable and meet the appropriate criteria.
It has been determined that disinfection rates typically correlate well with wastewater particle size distributions and that the ability to inactivate an individual wastewater particle is a function of the size of the particle. Direct tertiary filtration alone usually does not enhance the rate of disinfection unless the particle size distribution of the settled wastewater is modified. Tertiary filtration systems that operate to remove larger size particles should safely reduce the long contact times and high chlorine dosages typically employed in wastewater reclamation processes. Accordingly, granular filtration media is almost universally required as a part of wastewater reclamation. Granular filtration is somewhat time consuming and can be the limiting factor for a wastewater treatment system.
Masuda et al. U.S. Pat. No. 5,248,415 discloses an upward flow filtration apparatus that is said to be useful as a tertiary filter for wastewater treatment systems and to operate at a relatively high flow rate. An embodiment of the subject matter described in the Masuda patent is represented in FIG. 24 generally at 28 and is labelled Prior Art.
The filtration media described in the Masuda patent comprise a plurality of crimpy fibrous lumps. The fibrous lumps are disposed in the upward flow filtration apparatus 28 between first and second perforated panels 36 and 38, respectively. The wastewater flows in an upward direction through the fibrous lumps and suspended matter is captured by the individual fibrous lumps.
The first perforated panel 36 is immovably mounted within the apparatus and the second perforated panel 38 is movably mounted within the apparatus and spaced below the first perforated panel. The lower movable perforated panel 38, or bottom plate, is raised to compress the fibrous lumps to eliminate air gaps and to form a dense filter layer. The wastewater passes upwardly through the movable bottom plate and the filter layer and exits the top immovable plate 36. Fine solid materials in the upward flow are said to progressively adhere to the filter layer from the lower portion to the upper portion thereof in that order. With progressive filtration, resistance to filtration is increased. The movable bottom plate is lowered from time to time and is said to define a cleaning chamber when the filtration performance is reduced and it becomes necessary to clean the fibrous lumps.
However, the apparatus described in the Masuda et al. patent with the movable bottom plate has some difficulties associated with it. A ram or screw 40 for moving the bottom plate passes through the wastewater, the media, and the top stationary plate 36. The screw decreases the amount of room available for the media and potentially causes some channeling through the media in the region of the screw. The media are constructed of a loose fiber and can become entangled in the screw as it turns. A seal is used where the screw passes through the top plate, further complicating the operation of the device.
When the bottom plate is moved to compress the media, the lower layers of media become compressed. The compressed filter media in the lower portion of the bed is then the first portion of the media to contact the wastewater since the filter is operated in an upflow mode. The filter clogs up fast because large particles and fines are both trapped by the compressed initial layers of the filter media. The entire unit is shut down, usually before the upper filter layers are fully loaded, and the filter media is washed before the next cycle is begun.
The filter media is washed by moving the bottom plate downwardly away from the media to define a cleaning chamber. However, the flow rate of the wash water makes it difficult to achieve separation between the media and to obtain efficient cleaning. The Masuda device has typically required washing of the filter media on a frequent basis at a full flow rate of wash water equivalent to the flow rate of wastewater. Thus the overall efficiency of the apparatus described in the Masuda patent is greatly reduced.
It would be desirable to develop a filtration system suitable for tertiary wastewater treatment that substantially reduced or eliminated at least some of the problems associated with the Masuda device and yet provided a high rate filtration system as a suitable alternative to granular filtration media.


A bypass valve, particularly useful for allowing a tubing string to fill or drain during tripping in and tripping out, is disclosed. The bypass valve can be used in conjunction with a downhole motor operated through a tubing string. The bypass valve features a movable tapered valve member which has a smaller taper than the valve seat to prevent dragging the sealing element across sharp edges as the valve closes. Ports are provided through the valve to conduct upstream pressure in the valve behind the sealing element so that upon contact of the sealing element on the valve member with the seat, a boost force is applied to help retain the seal.

Directional drilling is frequently performed with fluid-powered downhole motors. The fluid-powered downhole motor is run-in on a tubing string which can be made of joints which are run-in from the surface in sequence. At the conclusion of the operation, the process is reversed. In order to put together the tubing string with the downhole motor so that the motor can be spotted in the appropriate location or advanced during the drilling operations, allowances have to be made for filling or emptying the tubing string as the tubing string is enlarged or shortened, respectively. That is, as additional stands are connected at the surface and run downhole, fluid in the wellbore needs to be admitted into the tubing string to prevent a pressure imbalance on the tubing string which would tend to put a collapse force on it. In essence, the bypass valve located adjacent the downhole motor admits well fluids into the tubing string as additional stands are added at the surface. Similarly, when the process is reversed, hydrostatically pressured fluid in the tubing string above the downhole motor drains into the wellbore as stands are removed from the top of the string.
Bypass valves have been used in the past which when in the open position, allow fluid communication between an annular space around the tubing string and the tubing string to facilitate filling and/or draining the tubing string during the operations of running in or tripping out of the hole. These bypass valves were designed to close if flow under pressure was applied in the tubing string so as to allow the downhole motor to operate. These valves presented reliability problems, primarily due to undesired leakage, which lessened the performance of the downhole motor. Accordingly, they have fallen into greater disuse due to their unreliability.
One such known bypass valve design is illustrated in FIGS. 1 and 2 of this application. A tubing string (not shown) is connected to the bypass valve 10 at thread 12. Inside of bypass valve 10 is a central bore 14 in communication with a sliding sleeve 16. Sleeve 16 is biased by spring 18 to the position shown in FIG. 1. In the FIG. 1 position, openings 20 are in fluid communication with annular space 22, which is in turn in communication with outlets 24. In the position shown in FIG. 1, the pressure drop without flow or with low flow across the sleeve 16 is insufficient to overcome the force of spring 18, and the sleeve 16 stays in the open position, allowing flow, represented by arrows 24, to go in either direction through openings 20. Below the lower end 26 of sleeve 16 is a seal bushing 28. Cylindrical seal surface 30 on sleeve 16 is pushed into bushing 28 when the spring 18 is compressed due to applied fluid pressures in bore 200 of sleeve 16. This position is illustrated in FIG. 2. At the lower end of the bypass valve 10 is thread 32 to which is connected a tubular 34, which ultimately supports the downhole motor (not shown).
Those skilled in the art will appreciate that rather than having a cylindrical sealing surface 30 being forced into a bushing such as 28, the body of the bypass valve 10, in the area of bushing 28, can have one or more O-rings and grooves or, alternatively, the cylindrical surface 30 can accommodate O-ring grooves and O-rings and have those rings forced into a seal bore which would be in place of the bushing 28. Regardless of the configuration, whether as shown in FIGS. 1 and 2, or through the use of O-rings, the problem of reliability of the seals has arisen. The primary reason for the problem is that the sealing medium, such as the seal bushing 28 of FIG. 1, is adversely affected by sharp corners, such as the edges of the openings 20 and the sharp corners 36 found at the lower end 26 of the sleeve 16. Grit in the mud is another source of potential seal problems. Another problem is that as soon as there is some sealing contact, such as between surface 30 and bushing 28, a differential pressure develops across the point of contact which further aggravates the interaction of sharp corners, such as 36, with the bushing 28. In essence, a shearing force acts across the seal which, if it is an O-ring, can rip it or yank it out of its groove.
For these reasons, the designs in the past, as shown in FIGS. 1 and 2, have proven not to be reliable and have gone into relative disuse. The absence of a bypass valve presents difficulties in tripping in and tripping out. While tripping out, a bypass valve is important so that fluid can drain back into the wellbore as stands are removed at the surface. Without such a bypass valve in the wellbore, when joints are unthreaded at the surface and if they're still full of mud, the mud will spill all over the rig floor. This creates environmentally unacceptable situations, particularly in offshore applications using oil-based muds. Without the bypass valve, each stand, as it is pulled out, is still full of mud which will spill out on the rig floor when a joint is broken. In running in, the bypass is important to allow the additional stands that are added to the string to fill as they are added. With no bypass valve, filling has to be done manually after every so many stands have been added to the string. If filling is not done manually and no bypass valve is operational to fill the string automatically, hydrostatic differential pressures can exist on the tubing which unduly stress it, possibly to the point of collapse if allowed to go uncorrected. Thus, in the past, operators have manually filled the string every 10 joints. This is a cumbersome procedure that takes time which creates cost for the operator.
Accordingly, the object of the present invention is to provide a reliably operating bypass which eliminates the design flaws of the prior art and presents, in a compact design, a valve which can reliably allow bi-directional flow until applied pressure from the surface closes it for operation of the downhole motor. Another objective in increasing the reliability of the bypass valve is to prevent dragging sealing members past sharp corners and to employ the pressures already existing in the valve for a boost force to ensure proper sealing once the sealing members have contacted. These and other features of the invention will become apparent to those skilled in the art from a review of the specification below.
Of general interest in the area of seals are U.S. Pat. Nos. 2,495,011; 4,256,314; 4,258,925; and 5,295,534.


A method is provided for forming films comprising Fe, Ru or Os employing the techniques of chemical vapor deposition to decompose a vapor comprising an organometallic compound of the formula (a): (CO).sub.4 ML or (b): M.sub.2 [.mu.-.eta.:.eta..sup.4 -C.sub.4 ](CO).sub.6 ; wherein L is a two-electron donor ligand and each R is H, halo, OH, alkyl, perfluoroalkyl or aryl; so as to deposit a coating comprising one or more of said metals on the surface of a substrate.

Vapor Deposition (to be referred to as "CVD" hereinafter) is a widely-used method for depositing a thin film on a substrate. CVD has been extensively described in the literature, including in the patent literature, and has been comprehensively reviewed by C. E. Morosanu in "Thin Films by Chemical Vapor Deposition", Elsevier, New York (1990).
In CVD, a heat decomposable volatile compound (often an organometallic compound), which may be called the precursor, is contacted with a substrate which has been heated to a temperature above the decomposition temperature of the compound. A coating forms on the substrate which may be a metal, metal mixture or alloy, ceramic, metal compound or mixture thereof and the like, depending on the choice of precursors and reaction conditions.
The desirable characteristics of CVD as a thin film formation method can include its ability to produce a thin film with good step coverage on a substrate having projections, the ability to readily control the composition of the thin film, and the ability to form a thin film without contamination of, or damage to, the substrate.
The deposition of metals from the vapor phase is important in many industries, including the electronics industry. In this industry, metallic depositions are often undertaken involving metals such as aluminum, copper, silver, gold, and tungsten. In particular, these metals are often used for interconnection lines for semiconductor chips, circuits, and packages. For microelectronic applications, it is often desirable to deposit films having high conductivity, which typically means that the films must have minimal carbon and oxygen contamination.
In the electronics and other industries, there is a growing need for volatile sources of different metals to be used in the CVD of metallic films, metal oxide films, metal silicide films, and the like. The key property required for such metal sources is that they readily evaporate or sublime to give a metal-containing vapor or gas, with or without the use of an additional carrier gas, which vapor or gas can be decomposed in a controlled manner to deposit a film onto a target substrate.
Another use of CVD is to deposit films of metals into vias, trenches, and other recesses or stepped structures. Since it is the situation that the deposition must often occur onto substrates which have irregular topography, a technique is needed to provide conformal deposition, i.e., deposition of continuous layers over irregular substrates. When conformal thin-film deposition is required, techniques such as evaporation and sputtering (which are line-of-sight techniques) cannot be used. Thus, CVD techniques are highly preferred for this purpose.
While CVD techniques have been described with reference to many transition metals and to certain other metals (such as copper) and metalloids (such as silicon), commercial use of CVD for the most part has been confined to deposition of a few metals and metal compounds, such as silicon, tungsten, and for the co-deposition of certain III-V and II-VI compounds (denoting, respectively, a compound of a Group III metal and a Group V element, and a compound of a Group II metal and a Group VI element) such as GaAs and ZnSe.
CVD of other metals has not been extensively practiced due to a variety of reasons including poor film quality, requirement of high processing temperatures, incorporation of impurities and other defects in the deposited film, lack of suitable precursor compounds, the inability to transport vapors of the metal complex without decomposition of the vapors, and the instability of the precursors used in the deposition systems. The availability of suitable volatile and heat decomposable compounds appears to be the greatest limiting factor in the application of CVD to the production of metal containing films.
In addition to the deposition of metal films, formation of transition metal oxide coatings on substrates by CVD is known. For example, see U.S. Pat. Nos. 3,914,515 and 4,927,670 describe depositing transition metal oxide films by contacting a cyclopentadienyl metal compounds with heated substrates in the presence of an oxidizing gas.
Chapter III-2 by W. Kern et al., in "Thin Film Processes", J. L. Vossen et al., eds., Academic Press, New York (1978) at pages 258-331 provides a general discussion of CVD of thin films with specific reference to metal oxide films on pages 290-297. Such metal oxide coatings are useful in photomasks, insulators, semiconductors, high temperature superconductors, and transparent conductors, and as protective coatings for high temperature materials.
A CVD method for forming films of refractory metals would overcome some of the problems associated with the use of volatile metals such as aluminum in the manufacture of high density circuitry. Ruthenocene, (C.sub.5 H.sub.5).sub.2 Ru, has been used in the CVD of ruthenium films (D.E. Trent et al. Inorg. Chem., 3, 1057 (1964)), but this precursor has a low volatility and requires a hydrogen carrier gas to deposit a pure film. U.S. Pat. No. 4,992,305 suggests the use of substituted ruthenocenes and osmocenes such as bis(isopropylcyclopentadienyl)ruthenium and bis(isopropylcyclopentadienyl)osmium as precursors for ruthenium and osmium CVD, but no examples are given.
Osmium tetrachloride has been used for the CVD of osmium films (S. Lehwald et al., Thin Solid Films, 21, S23 (1974)), but this precursor undergoes considerable decomposition at the temperatures required for its volatilization. Thus much of the precursor is lost in nonproductive reactions. Additionally, high substrate temperatures of about 1250.degree. C. are required for the osmium deposition.
Ruthenium films have been formed by a chemical spray deposition process (J.C. Viguie et al., J. Electrochem. Soc., 122, 585 (1975)). Tris(acetylacetonate)ruthenium in butanol is converted into an aerosol spray using a hydrogen/nitrogen mixture as the carrier gas. Triruthenium dodecacarbonyl, ruthenocene, and tris(acetylacetonate)ruthenium were compared as CVD precursors in the formation of ruthenium and ruthenium oxide films by M. Green et al., in J. Electrochem. Soc., 132, 2677 (1985). None of these precursors are very volatile and thus high deposition rates were not attained.
U.S. Pat. No. 4,250,210 discloses the use of tris(acetylacetonate)ruthenium and its fluorinated derivatives in the CVD of ruthenium films. The fluorinated ligands provide greater volatility and good deposition rates are achieved when the precursor is heated to over 200.degree. C. to assist its volatilization. However, difficulties due to the stabilities of the precursors are noted and freshly prepared precursors are preferred as aged samples yield inferior coatings. Organic byproducts, presumably oligomers of the acetylacetonate ligands, with very low vapor pressures are formed and collect in the reactor. These liquid deposits represent a serious contamination problem in a production scale application of the tris(acetylacetonate)ruthenium precursors. This reference also alludes to the use of ruthenium carbonyl chloride and penta(trifluorophosphine)ruthenium as precursors for ruthenium CVD. However, these compounds are said to be unsuitable for general use because the rates of deposition of ruthenium that can be obtained are very low. Therefore, these precursors can only be used to deposit very thin coatings which exhibit poor adhesion to substrates. Additionally, ruthenium carbonyl chloride corrodes certain substrates and it is difficult to obtain a consistent product in its preparation. This lack of consistency in the product can show up as a substantially nonvolatile form of the carbonyl chloride, which decomposes before it can volatilize.
Although ruthenium thin films have been difficult to prepare, ruthenium and ruthenium oxide have been shown to have utility as electrical contact materials (R.G. Vadimsky et al., J. Electrochem. Soc., 126, 2017 (1979)). Ruthenium oxide and ruthenium metal have similar electrical conductivities and both show good environmental stability. Films of ruthenium and ruthenium oxide deposited by CVD have been proposed to be useful for contact metallizations, diffusion barriers, and gate metallizations (M.L. Green et al., J. Electrochem. Soc., 132, 2677 (1985)).
Ruthenium oxide electrodes, some prepared by CVD, have shown utility as working electrodes in nonaqueous solvents (D.R. Rolison et al., J. Electrochem. Soc., 126, 407 (1979)). Thin film multilayer cobalt/ruthenium structures, prepared by sputtering techniques, can exhibit novel magnetic properties (S.S.P. Parkin et al., Physical Review Letters, 64, 2304 (1990)). In U.S. Pat. No. 4,250,210, CVD films of ruthenium on cutting tools can increase the cutting life of the tool.
CVD of iron using iron pentacarbonyl is well known in the art. This precursor is commercially available and is very volatile. However, its high volatility makes iron pentacarbonyl unsuitable for many applications, such as its use as a dopant in semiconductor manufacture (J.A. Long et al., J. Crystal Growth, 77, 42 (1986)).
As described by C. E. Morosanu on pages 460-475 in the previously cited book, iron CVD has shown utility in preparing garnets and ferrites useful as electronics, microelectronics, microwave electronics, optoelectronics, and the like. Additional utility has been shown in the preparation of Permalloy (Ni-Fe) magnetic films, photolithographic masks, and inorganic resists for laser and electron beam lithography.
Thus, a continuing need exists for improved organometallic precursors useful for the CVD of films of iron, ruthenium and osmium.

Chemical vapor deposition of iron, ruthenium, and osmium

Minnesota Mining & Mfg. Co./Regents of the University of Minnesota


Modified branch metrics for processing bit-soft decisions to account for phase noise impact on cluster variance (CV). The present invention is able to partition a modulation scheme's constellation into two or more regions, so that the bit-soft decision branch metrics may be adjusted based on the CV of the various constellation points. A confidence level may be attached to the various constellation points based on their particular CVs. There are a number of methods to ascertain the CV of the constellation's points, including finding characteristics of various components in a communication system (transmitter, communication channel and receiver), and any method may be used within various embodiments. The modification of the branch metrics/confidence level may be performed in a communication receiver; the communication receiver may be implemented in a communication system employing the vector orthogonal frequency division multiplexing (VOFDM) portion of the broadband wireless internet forum (BWIF).

1. Technical Field
The invention relates generally to communication systems; and, more particularly, it relates to a system and method that are operable to perform modification of branch metrics/decision metrics for processing bit-soft decisions to account for phase noise impact on cluster variance.
2. Related Art
Communication systems transmit digital data through imperfect communication channels. These symbols may undergo some undesirable corruption due to the imperfection of the communication channel. One effort to try to avoid such situations is focused on performing forward error correction (FEC) coding. However, there is typically some difficulty in extracting the information contained within these symbols after they have been undesirably altered within the communication channel. There exist some methods that seek to curb the effect that the communication channel has had on the data; one such method includes employing using Decision Feedback Equalizers (DFEs). However, even after the incoming signal has been equalized, the extraction of the data, that has undergone some alteration due to the channel effects, is still a probabilistic determination.
Many communication systems, particularly in a receiver, need to perform the analog to digital transformation of an incoming signal. In doing so, there is oftentimes an uncertainty in whether a sample of the incoming analog signal is properly transformed into a 1 or a 0 in the digital realm; for example, there is not a 100% certainty that an incoming signal is actually a 1 or actually a 0—there is some probability associated with the decision. In higher-level encoding/decoding systems, e.g., QPSK/4 QAM, 16 QAM, 64 QAM, 256 QAM, and 1024 QAM etc., there are several bits per symbol that need to be transformed to either a 1 or a 0. In 16 QAM applications, a receiver extracts 4 bits of data from each symbol. In the QAM modulation scheme, each symbol includes an in-phase component and a quadrature component. For the 16 QAM modulation type, the decision block maps the in-phase and quadrature components contained in the symbol to a 16 QAM constellation and decides the values of the four bits that are carried by the symbol. Within these various systems, the constellation points that are used to modulate/demodulate the data do not all have identical cluster variances (CVs).
The decisions made in extracting bits from a particular symbol are referred to as "bit-soft decisions." Bit-soft decisions not only map the symbol into bits but also produce a decision metric/branch metric related to the probability that the decision was correct based upon how well the received, in-phase, and quadrature voltages of a symbol correspond to the symbol in the constellation. The terminology of "branch metric" is often used interchangeably with "decision metric," and this convention will be followed in this document. The decoder operates based on the premise that there are only a finite number of possible states of the encoder and that given a certain number of consecutive states, the input bit may be predicted that would have caused a particular state transition. The decoder generates a "branch metric" (or "decision metric") for each of the possible "state transitions" from one state to another. The coding method maintains a "decision metric" associated with every state that is the sum of the metric at its predecessor state and the metric associated with the branch that caused the state transition. This metric may be termed the cumulative metric or accumulated metric, and the decoder generates the cumulative metric for all of the states. The different states and the transition from one state to another can be represented in a diagram, namely, a trellis diagram. For various possible allowable state transition sequences through the trellis (the allowable paths through the trellis), the decision metric associated with the sequence of branches of the trellis diagram are summed together, and the smallest sum is selected as the actual state transition and enables the identification of the best estimate of the decoded data. It is also noted, without loss of generality, the sign of the metrics may also be changed so that the largest sum would be the best estimate.
As mentioned above, the constellation points that are used to modulate/demodulate the data do not all have an identical cluster variances (CVs). Conventional and prior art commonly calculate the cluster variances of points within the constellations used to demodulate received data. Oftentimes, the cluster variance of the constellation points closer to the origin of the constellation is tighter than those further out from the constellation's origin for the same signal to noise ratio (SNR), particularly for higher SNR where phase noise is significant, and the larger energy constellation points are further from the constellation's origin.
Some communication systems are particularly susceptible to phase noise in the signal. When a communication receiver demodulates the data, the phase noise can be problematic, in that, the various points in the constellation may have significantly different cluster variances. In some communication systems, such as multi-tone modulation formats, the degradation of a transmitted signal, due to phase noise, is increased by the interaction of the various tones within the transmitted signal. Phase noise may also be introduced by inadequacies in the sampling portions of the receiver, including phase noise inherent in the generation of the LO (local oscillator) used for down-converting from the transmission frequency. (Similarly, phase noise is introduced at the transmitter as well.) In higher order modulation types such as 16 QAM, 64 QAM, etc., this phase noise has a large impact on the mapping of symbols into the constellations. Phase noise will often cause outer-constellation points to have a greater cluster variance than inner-constellation points for an equal phase noise contribution, again, in a situation where the SNR is relatively high. To illustrate this situation in one embodiment: for a 16 QAM implementation, outer constellation points will typically suffer nine times as large of a cluster variance (three times standard deviation) for a same amount of phase noise as compared to the inner constellation points. The bit soft decisions that are generated and provided to a decoder are ultimately significantly affected by any introduction of this phase noise.
Further limitations and disadvantages of conventional and traditional systems will become apparent to one of skill in the art through comparison of such systems with the invention as set forth in the remainder of the present application with reference to the drawings.

Modified branch metrics for processing soft decisions to account for phase noise impact on cluster variance


Appliance for preparing a froth from a milk-based liquid which includes a tank for receiving liquid that is to be frothed, and in which liquid a rotatable stirrer is positioned, a stand associated with the tank, and a system for driving the stirrer. The stirrer drive system and the stirrer include magnetic elements allowing the stirrer to be rotationally driven magnetically in the tank. At least one disturbance member is also provided to break or prevent symmetric circulation of the liquid about the median vertical axis of the tank.

The present invention relates to an appliance and to a method for preparing a froth from a food liquid such as milk and is intended, for example, to be used in the context of the preparation of beverages such as cappuccinos, milky coffees, cafe latte and macchiato, hot chocolate and other speciality hot beverages.
Speciality beverages in which at least a portion is made up of froth are increasingly becoming all the rage. The best-known beverage of this type is a coffee of the cappuccino type. It comprises a liquid portion consisting of coffee topped by a layer of frothed milk which, because of its very much lower density, floats atop the surface of the liquid. In general, preparing one takes time, manipulation operations and cleaning.
The most customary way of preparing a milk-based froth is to pour the desired amount of milk into the container, immerse a steam outlet pipe from a coffee machine in the container, agitating it up and down to introduce the air needed to form the froth.
A first disadvantage with this method is that it entails having a coffee machine equipped with a steam outlet, and not all machines are.
Another disadvantage lies in the fact that it is generally not possible to prepare the froth at the same time as preparing the coffee, unless a complex and expensive machine with two separate fluid circuits, one for extracting the coffee and the other for producing steam, is available.
Another disadvantage associated with the use of coffee machines with a steam outlet stems from the fact that the system for heating the water in these machines, most often a thermoblock, has to be kept constantly switched on in order to produce the steam without having to wait. These machines therefore consume large amounts of power, which makes them not very economical to operate. It must also be noted that steam pipes soon become scaled up when the water used is hard water and this entails regular maintenance in order to keep them in good condition.
Another disadvantage with this type of machine stems from the fact that the quality of the froth is dependent on the skill of the user which means that these machines do not allow the froth obtained to have reproducible properties and a uniform quality.
Another disadvantage stems from the fact that the pipes in contact with the milk are difficult and not very practical to clean.
There also exists mechanical stirring appliances which are usually intended for domestic use for beating froth from more or less viscous food products such as eggs, ice, juices or the like. The problem with these appliances is of several natures which means that they are ill-suited to producing froth from a milk-based liquid for making a beverage. One disadvantage, for example, stems from the fact that these appliances stir a liquid or a paste in the cold state, considerably limiting their potential use. In addition, milk does not froth as convincingly when cold or at ambient temperature.
Another disadvantage stems from the fact that these appliances are ill-suited to frothing the microbiologically sensitive liquids such as milk. Regular cleaning of the tank of the appliance needs to be envisaged in order to remove any solid food residue. In addition, heating the milk has a tendency to increase the extent to which cooked or burnt proteins are deposited on and adhere to the surfaces. The existing appliances are not, for the most part, well suited to reducing the encrustation of this solid residue, making cleaning troublesome.
These appliances also have a stirring and driving mechanism which is fixed and intrudes into the tank, and this presents several disadvantages: the removal/refitting time is not insignificant, they have a tendency to become soiled more quickly, they entail additional cost as a result of the multiplicity of components, and the stirring means are difficult to clean.
Another disadvantage with these appliances stems from the fact that frothing in these appliances is not optimal for reasons associated with the arrangement of the stirring means. Some appliances have a stirring means positioned in the middle of the tank. Such an arrangement is not efficient in quickly converting a volume of milk-based liquid into a rich froth.
Other appliances have several stirrers. These arrangements are generally mechanical with gearing means needed to coordinate the rotation of the stirrers, and this makes the system intrusive, and therefore less hygienic, increases the number of parts and makes cleaning a more painstaking operation.
U.S. Pat. No. 6,318,247 relates to an appliance for preparing hot beverages or food with stirring such as hot chocolate, for example. The appliance comprises a system for driving a stirrer of the magnetic effect type. It does, however, have several disadvantages. Firstly, in such an appliance, the liquid or froth is stirred coaxially with respect to the central axis of the tank, and this causes a circulation in which some layers of liquid or froth, particularly the peripheral layers, are not stirred as extensively as others, particularly the layers near the middle, because of the centrifuging effect produced by the stirrer. Such a circulation is therefore not suited to producing a froth of sufficient quality or to reducing the time needed to produce this froth. In addition, the structure of the appliance is not hygienic for treating a milk-based liquid and cleaning is not made any easier by such a construction.
Other devices for stirring food products which have more or less the same disadvantages are described in patent documents WO 2004/043213 A1 or DE 196 24 648 A1.
Other stirring systems of the magnetic engagement type are described in U.S. Pat. Nos. 2,932,493, 4,537,332 and 6,712,497 and in German patent application DE 1,131,372, but none of these provide solutions suited to producing a quality froth in a short time and hygienically.
German Utility model DE 89 15 094 relates to a refrigerated pot for dispensing a milk-based beverage. The pot comprises refrigerating means and forced-convection means in the form of a magnetic rotor. Such a device is not suited to converting the liquid into a froth but simply keeps the liquid uniformly at the refrigeration temperature for preservation.
U.S. Pat. No. 3,356,349 relates to a stirring device comprising a heated tank, magnetic driving mechanism positioned under the tank for driving a hub located in the middle of the tank. The hub is associated with a stirring element which is offset with respect to the hub, causing the element an oscillatory movement. Such a principle of stirring may create a loss in magnetic coupling because of the high moment of inertia generated by the offset position of the stirring means with respect to the axis of rotation of the driving mechanism. This problem increases with increasing speed. Such a stirring device can therefore work to stir certain liquids or other substances at low speed but may prove ill-suited to converting liquid into a froth at sufficiently high speed. Incidentally, the document does not mention the conversion of a liquid into a froth using this device.
Thus, there is a need for a device that overcomes the disadvantages of the prior art, and this is now provided by the present invention.

Appliance and method for preparing a froth from a food liquid